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i ~ Iducation, ~( Health~ ~ fIea:lth, Advisorg p: Wash- Public Public Ilking. A ~ti, Ed'u- 11'ioati'on ~ bg: 1.968 kirttnent ,5hrvioe ~g. 1989 ~rtnient 5ervi~ce~ Iing. A 4, Eflu- [ ) Zi- ~ng: A Edn. ) 72'- j men ioine 1teki :. (2) i l4ue: rimo- >olic 458,. I

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Co~mtemts Page Introductiom-------------------------------------------- 67 ILiing Cancer-------------------------------------------- 68. Egidemiologieal St2idies-__-____________________-____-_ 68' E'x-Smokers----------------------------------------- 71 Lirdnium, Mining and Exposure to RadioactivztV _ _ _ _ _ _ _ _ - _ 72' Air Pollution---------------------------------------- 72 A'sbestos-------------------------------------------- 73 au,topsyand Cytol'ogical SGudies-__--_-_____-__-___-____ 73 nral Cancer -------------------------------------------- 74 Cancer of't.he Esophagus_________________________________ 76 Cancer of t'he Larynx ------------------------------------ 76 Cancer of'the Pancreas___________________________________ 77 C aneer of the Kidney andl Urinary Bladder_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 77 E_.perimentall Carcinogenesis-__________________________-__ 78' R'espzratory Tract Carcinogenesis'_ _-- _ _- _ _ _ _ _ _- _ _ _ _ _ _ _- _ 78' Experiments in Mice_________________________________ 80 Aryl Hydrocarbon Hydroarylase (AHH), _ _ _ _ _ _ _ _- _ _ _- _ _ _ _ 82 Cell an.d Tissue Culture Studies_____-__________________ 84! B~inding of ~Polycy,cli;aH'ydrocarb'onst~~o~~DNA~ dnd~RNA_ __- 86 AT-lVittosdmines in Toba.cco Smoke_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 87 Summary of Recent Cancer Findings_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _. 88 Referenees--------------------------------------------- 88 List of Figures Figure 1.-Standardized lung cancer mortality ratios of' Japanese by number of' cigarettes smoked (1966-70) ------- 69. Figure 2'.-Lung cancer mortality ratios of Ja.panese by age, at initiation of' cigarette smoking (1966-70) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 69 Figure 3.-The survivall of'~ ex-srnokers and continuing smokers who were treated for a primary cancer of the oral cavity, pharynx,orlarynx------------------------------------ 75. 65

List of Tables Page Table 1.-Age-standardized lung cancer death rates of' British physicians and the population of' England and `?Pales at various time geriods----------------------------------- 70 Table 2.-N-dimethylnitrosamine (DMNA) content of'~ con- densates obtained from several tobaccos grownn in both! . "high"' and "low" ni~~trogen soils------------------------- 87 ' 66

Introduction Tiiis introduction is a brief summary of' the major relationships brt weensmoking, and cancer which have been established in, previous nvl)orts on the healahi consequences of smoking', (;9~L,92,93,,94, 95, 961)~. ('i'(;arette smoking has been clearly identified as the major cause of 14u1- cancer in the TJ.nited S'tates:This conclusion is based on detailed vhi'kllniiological, clinical,autopsy„ and experimental data, which have :uccutnulated over a period of more than 20 years, For both men, and woxmeii,, the~ risk ofdevelopinglung; cancer is directly related to total klxpostu•e to cigarette smoke as measured by the number of cigarettes smoked per day,, the total lifetime number of cigarettes smokedl, the duration of' smoking in, years; the age at initiation of smokingy the depth of inhalation of tobacco smoke; and the "tar" and nscotine levels in the cigarettes smoked. Lung cancer death rates, however,,are lower for Nc•,omen than they are for men, ai finding due, in part;, tloa differencein exposure. `Vomen, smokers use fewer cigarettes a day, choose filtered cigarettes with lower"tar'''' and nicatine~ val!ues,, and also tend to inhale less. E-Iowever; even when women experience comparable levels of' ex- posure to cigarette smoke as men, their mortality rates for lung cancer stiill remain somewhat lower. Those who stop smoking experience a decline in the risk of'develop- ing lung cancer relative to continuing, smokers. The air, pollution! commonly found inan urban setting, appearsto result in elevatedllung cancerdleathi rates; however, thiseffect is relatively small comparedl to the overriding effect of cigarette smoking:. Certain occupational exposures have been found tio be associated with ani increased risk of dying from, lung cancer. Cigarette smoking interacts with many of theseexposures!.toproduce much higher death rates from lung cancer than would result from one e.xposure alone. Inte racting exposure factors may be : experiencedl simul'taneously or at~ different times. The uranium mining and asbestosind'ustries,are exam- ples of occupations in which this interaction occurs. The bronchial epithelium of smokers often shows premalignant changesincludingsquanlous,m!etahlasiay atypical squamous metaplasia,, and carcinoma in situ. Pipe and/or cigar sinokers experience a risk of developing lung cancer that is higher than t'herisk of nonsrn~o~kers;howe,ver, it,remains 495-028 Q'--73 M ,. , d

significantly lbwer than the risk of'cigarette smokers. A more complete discussion of the risks from pipe and cigar smoking, is found in another chapter of this report. Epidemaolbgical, experimental, and autopsy data have demonstrated that cigarette smoking is, a, significant factor in the development of cancer of the larynx, oral cavity, esophagus, and urinary bladder. B-naphthylamine, a carcinogen known to cause cancer of the urinary bladder in humans, has beenidentiified in cigarettesmoke. Thereisalsoe an association between cigarette smoking, and cancer of the pancreas. Experimental studies with animals in which cigarette smoke or one of it's const!ituent' compounds is administered in & variety of assays have confirmed the presence of'complete careinogens„ cocarcinogens such as tumor initiators and tumor promoters, and tumor accelerators in cigarette smoke. Reeent'1y, additional epademiological, autopsy,, and experirnental' studies have added to our understanding of these rel'ationships., Lung, Cancer Epidem,ialogical Sta.t,dies An ongoing prospective epidemiological study condtzcted in Japan provides a unique opportunity to examine the relationship of cigarette smoking ta death~ rates in a population: withgenetic, dietary, and other cultural' differences from previously examined Western popula- tions., Hirayama (37) has now reporte6 5-year foll'otivup data on 265,118 men and women aged40 y ears and older.. This represented 91' to 99 percent of the total' populatiotr in the area of' the 29 health districts where the study was conducted. A totali of' 11,858 deaths occurred dur- ing, the 5-year periodl which incUaded a total of 1,269,382 person-years of observation: Both men and' women wh.o sm.oked cigarettes experi- enced higher death rates from lung cancer than nonsmokers. Among smokers,the lung, cancer mort<alityratio«-as3'.85 ~ fbr men and 2:44 for women as,compared to nonsm~okers~ . (P < 0.001). Dose-response, relation- ships were demonstrated for the number of' eigarettes smoked per dayy andl the age at initiation of smoking (figs. 1 and 2). These mortality ratios,areconside-rablylower than those reported, forthehnited States, Canada,, and Great Bri~taQn, and may reflect ai lowerar-eragenumber of cigarettes smoked a da,y;an olcder.age at imitiation of smoking, or re- duced inhalntion ofe cigarettle smoke among the Japanese. In spite of these differences, thee overall results,of'thisstudy, includingthe dbse- responserelationships, are similar.toAhe resnlt&ofal'l the other major., 68

r'"`w I I l~lete. ~ rated~ it of Ider. h.ary i alsoo reas: ke of. Rave. ~11 as ~ in. I t~tal el,iiioiui,ological investigations. Thus,the rel'iabilityand accuracyof'the iictliods of' population selection and analysis used in previous studies h;r~e<i on population sa,rnples,and the conclnsion that cigarette srnok:- w,L, is the major cause of'lung cancer are again confirmed. Figure 1.-Standardized lung, cancer mort~aiity ratios of'Japanese by number of cigarettes smoked (1966'-1970),. 9'.0 S!.0 7.0' 6.0' 5:0 4.0 3~.0 2'.0 1.0'. 0 1.0 3.6 4.4 7.8' 4.3 Mlorn 1-14 15-24 >24 Ex, smoker cigarettes per day smoker SOURCE: HfFayamaj T. (37). Figure 2.-Lung, cancer mortality ratios of Japanese by age at initiation of cigarette smoking (1966-1970). 5,0 A~ 4.0~ r. 0 2 3',0! 2.0 11.0 ' 0 Non- >25' <24 <19 smoker Age at initiation of smoking SOURCE: Hirayama, T.,(37): 69 0 0 79

TABLE 1I.-Age-stand'ardized lungcan.cerdeath rates of Briti:'sh, physicians and the population of England and Wales at vdrinus time periods Lung cancer standardiied!deiath rate per 1,6C10 men per year in- Dootors. England and Wales Years------.--,-------------------------------------- 1953;-57 185741 196i-65 19M-57 19,58-611 1962-65 Death rate per 1,000~----------------- 1. 10 0. 85 0. 83 1l 49 1. 71 1. 88' Source: Doll, R., Fllee;D3.,C. (tt). Kennedy (~.45); studied primary lung cancer in 29 men and 11 `eomeni diagnosed before the age of 40 land found a strong association betweeni cigarette smoking and'the development of this disease. Boucot, et al. (11) further characterized the 121 cases of lung eancerdetected in the population of tiliePhiladelpllia pul'monaryneoplasm research project. Ti he risk of developing lung cancer in- creased with age, was higher ini nonn-hites than in whites, and increasedd sharply with, increased cigarette consumption. The relationship~ between cigarette smoking and lung cancer was investigated in a retrospective study by: Ferr.ara (25) in La Plata, Argentina. The: smoking,habits of 144' lung cancer patients were con- trasted with those of 386' controls. A dose-response relat'ionship, was found between cigarette usage measured by the number of cigaret.tess smoked per day and the durat'i'on of smoking,and the risk of'develbping lung cancer. A high incidence of' lung, cancer is reported from the island of Jersey in the Channel Isles compared to England and wales.. The island has no heavy industry and only minimal levels of air pollution. Cragg (16) ~ studied 144 patients who developed lung cancer on Jersey during a 4-year study period. Only three nonsmokers were found among the 113'patients for whom histories were available: Fingerland; et al. (26) determsned' the prev.alence of! 1'ung cancer and certain other diseases in an~ autopsy series of 1,338 adults in Czechoslovakia. Some 198 cases of primary lung cancer were identifiedl. In the autopsyy population, 1.4 percent of the nonsmokers, 14'.1 percent of'thosesmoking Tesst11~an200,,O0b'lifetime eigarettes,, and 33.3' percent of those smoking more than 500,000 lifetime cigarettes had lung, cancer. Rickard and Sampson~ (71)~ studied 94 Negro patients with lung, cancer in Washington, D.C.,, and found, that 57 (92 percent) of 63 patient's whose smoking history was available were: regular smokers. Epidemiological studie& conducted in Italy (10)i,, Swe,deni (48), Poland (46), Russia, (42), Cuba (73), 11Tiexico (13), and the Nether- lands (98) demonstrate an association between cigarette smoking and, lung eancer. 70 I # i

omen fween lung mary LC In- ~ased was lAta,, iCon- I was Oes ?ing ~ of T'he. :ion, hsey und icer li in led. ent ;ent tng [ng 63 irs. id Berg, et al. (5) examined the incidence of recurrent primary cancers following initiall prirnary~ cancers~ of~ the~ respiratory and upper di- 'restiti-e systems in New York. During 23,802 man-years of observation in .1,11i5 patients with an initial squamous cell cancer,, 518 second cancers developed at other sites. Patients whose first primary cancer ;nas in the lung had an observedl to~ expected relative risk rat'io~ of' 5'.:7~ ( P< 0.05 ) forr subsequent cancers of' the respiratory or upper GI ~,V:;tem~. Patlient'is, with the~~ first cancer in the~ oral cavity or~ laryna frea(luently developed a second cancer in the lung.. AIiedical records _ ontirnaed long sTnoking, histories among almost all of' these patients Nti IioAeveloped second cancers. C'uncer~~of the~ lung~, oral cavity, larynx, and esophagus were~~ reported !~v Schmidt and De~ Lint, (79)~ to be~comrnon~ causes, ~of~death~ amongg f,WN ' men and women who hadl received treatment~ for~ alcoholism~ in~ Toronto. The authors attributed this finding to the strong, associa- t irn.t that exists between alcohol and tobacco~ u~se~andnot bo~~ the~effect of zi Lcoholl alone. Carcinoma of the trachea is~ a relativeiy~ rare~ condition with, only ahout-1D0 cases~ha:ving~bee~n reported in the literature~.,lii a study~ of~41' l)atients~ w~ith, carcinomai of~ the trachea, I}Iaj'du,: et~al. (.31) found an, ~-,Pparent association between cigarette smoking and the development =4 'epidermoid cancers,of this st'ructure:~ An association between ci:garette~ smok~ing, and the development of~ broncliu:olo-alveolar~ carcinoma in~ 74 patients-~was, described~ by ~ Delarue;~ et al. (18). . Ex-sm;okers Those who stop smoking experience a decline in the ri'sk of dev.elop- ing lung, cancer relative to continuing smokers: Doll and Pike (2N) <<onducted a~~ st~udy~of~ the~ smoking habits and causes~~of death of 40,000~ Briti,sli physicians. Smoking ha.bi~tis, were~ surveyed in~~ 19~511, 1957',~ and . l:)6G., Durii,2;, the~ study ~ perio<l,, more~ than 3,500 physiicians~ becan:ze~ ex-~ .~niokers~., The age-standardized percentage of ex-sni,okers~~ among 1?hy~-~ sicians 65 to 64 years of age rose from 1I8',1 percent in 1951 to 26,5 per- cent in 195 1 and ~?~J~:5 hercent, in~ 1966. Concurrently, t~h,e~percentage~of hhy:sicians~ s~nioking, ci~,rnrettes~~ fell fi-om, 44.1 percent to 22.0 percent, while over ~ the~ same period estimates of' the~~ per capita ci'garet;te~ con- sttmption for the adiilt male population in the~ Linited! Kingdom su~g- (*este<1 ,t slir.ht increase in ciga~ret-te~~ consumption. Over this 15-year~ heriotl, the~ niorttility from hu2g,cancer arnor:7g,physicirans~~dlrophed con- sidera1hly: While~~ lung cancer death rates among,the nnale population in 1!ar,aand and Wales increased to~ some~ extent (tla~ble~ 1)~.: :llthougll cer~- 71

tain limitations apply to the interpretat,ions derived from secular data, analysis~ of the~ study ~ design and the~ magnitude of the results~ ihdi-~ cate that~this study constitutes important evidence~of~some~of'the~bene~-~ fits~~ tliat'~ result fi•onii the cessation of~ cigarette snsoking. Uranium Mining and Fxposure to Padioaetivity Epidemiological evidence supported by autopsy studies has estab- lished that'~airborne~radiationy~ particularly~ in synergi~stie~comb~imation «itlrcigarette smoking,,is the major cause of the excess of respiratoryy cancers among uranium miners. Lundin;, et al. ('53), considered quantitative~ and~~ temporal aspects! of radon.idaughter~exposure and respi'ratory~cancer ini a report'~~fromthe: Epi~d!emiologica1 Study ~ of~ United States~ Uranium Miners. They~ ob-~ served a stati~stiicalZy~ significant excess~~ of~ respilratory~ cancer among «hi~te~u~raniom mii7ers~~at each cu~mulative~~ radiation exposure category dow~n to~~ and' including~ 120-3W WL'M (w~ork~~ing~~ llevel montlLs)~_ The authors~ noted that although cigarette~ smokiirg~ alane~ entailed a risk of the~ dl;~veloprnent, of' eancer~ of~ the respiratory.~ tract in, miners just as it~ does in nonm~iners; cigarette~~ smoking, in combination wi'th; radion~ daughter exposure appeared to result in an even greater risk.~ Several authorsi (30, 44,~63„8/~~, 104) continuelo~ report the presence~~ of' polbni~um-~210 or~one~of the~th:oriurn isotopes in tobacco l~eaf;~ tlobacco~o smoke, or the l ungs of smokers. Air Pollution Data standard'ized, for~cigarette sm:oki~ng~~ind'icate~the existence:of an~ u~~rban factor~in the~develapm~ent of~lung carlc;er; it is~likelythat ai'r~po1- lution,,frequent,ly~ part~ofi the city.~ environment, is~ai component of~ the~ urban factor. Th~e~ National Academy of~ S'ci~ences,published a review (6r')~ of the~ biolbgicall effects of atmospheric polluti~on~ by~ particulate pol!ycyclic~c organic matter.~ Detailed epidemiological,,experimental, physicaI,,and chemical data were revie«-edi., It was concluded that air pollution„ as commonly ~ found in urban settings, was found to~be associated with: in- creased creased lung cancer~ mortality in cities, An examination of the data presented,~however, indicates that eigarette~ srnok~ing is,,i¢l, most~ cases, the~ overridia'ig factor~ in tihe~ development of lurrg, cancer. IPolycyclic hv~d~rocarbons~an~d relatedlcompourrds which~aire~known~to~cause,cancer of the~lhng and other organs in experimental animals were~ found t'~o~ 72 I

ftr data, ~indi- le hene- I estab- ~ation ratory i 'spects Im tlie. Ey ob- ~nong egory. ; The jsk of ist as ~adon ~ence laceo: be p resent in relatively high~ concentrations in cigarette smoke; inlarge ,1u,1ntities in: the~ air of industries in which workers have high-Tung, ,•~mcer rates,, and also in the air of urban communities. Sterling and Pollack(~86)~ reviewed theeffect!sof' air poldutionon, ,leath rates! from lung cancer. They suggested that partielesresulting, f rom the combustion of' organic fuels may be more strongly related to thc incidence of lung cancer in the populkation than cigarette smoking. 'Irhe eumulat'ed epiderniological dat'aregardiiircigarette smokangand ltnu; cancer were not considered by the authors in this report. Asbestas. Ogarettesmoking asbestos workershave, ma~rked2'yelev~ated Iung(I:uicer dleath rates compared to: nonsmoking asbestos workers. Berryi6) examniedt.he combined etfcct~of asbestos exposure~ and smoking on mortality from huig cancer among 1,300 male and 480 female asbestos f„lotory workers over a 10-year period. There was no significant i'n- cr.ease in llung cancer mortality amon~g smoking or nonsmokingn orkersn-ith a law-to-moderate exposure to asbestos. Ho«•ever; among smokers «-ho had heavy exposure to asbestlos,, 32'. lung cancer deaths occurred among 663 men (9.9 expected), and there were 1& deaths among 292 n-ouien (1'.4 expected). This confirms the greatly increased risk of de- veloping lung cancer among asbestos «~orkers who smoke cigarettes. Autops y and'Cy,tolog,icad Studies f'an pol'- 'the the 'clic and y as in- ata ?es„ sl'ic ser to! The respiratoryy tract of cigarette smokers examined at autopsy flre- qttentIy demonstrates epithelial changes consiidered to be precttrsors of bronchogenir; carcinoma. Such changes include squamous metaplasia, atypical squamous metaplasia, and carcinoma in situ. Herrold (35) studied histolog~ie~ types of prirnary~ lung cancer~in, U~.SL~ vete,rau& who .vere~ subj~ects~~ of~ the Horn study. Q!f~ a total of, 2,241 wh~ite~~ male~ vetr~ eraais who died of lung cancer over an 8-year period~ histologic mate- rial «-~as~ a-v~a~ilable~ fbr.~revie« in 1,477 7~ patients. Histologic types were~ rroul~~ed according to the~ Kreyberg classification of Gsoups~ I anld H tniil,ors. Group I tuaimors~, epidermoid and oat-cell carcinomas, were~ prePs{>>it in 2~7::3'~ percent o£~ the~ 55~ nonsmol.ers~ and were~ present in 57~.8~ hercei~it~of tlie~~4l72 "cnrrent~smoke,rs~~of cigarettes~only.?'Thedi'tfere.nce \v~as statli'stically~ sipnaifi~cant (P<0.01?1~):, confi~rming,tlic~strong, associa-~ tion behveen cigarette~ snioking~~ and Kreyberg'Group~ I tumors. 71 ;Q tj O

- ~i Auerbach et al. (2) examined epithelial changes in the bronchial tree ~ of 456 men, and 302' vr omen who had died of' a cancer other than lung ; cancer. There were 72 ex-smokers among the men, all of whom had '' smoked for 10 year&or more buti had'quit smoking for at least 5 years prior to death. Atypical ceils were present in 93'.2 percent of the current ~ The prevalence of atypical cells (hyperplastrc and metaplastic) in the sputum of 1221ma1e and 128 female «-orkers was examined by Rob- bins (72). These smokers, all under the age of' 10; were mat'ched' with a control group d~rawnfrom a population ofcollegestludents. Atypical cells were found in 14 percent of the smokers andl 5' percent of the non, smokers: smokers; 6.0 percent of the ex-smokers, and 1.2 percent of' the non- I smokers. Areas of epithelium composed entirely of'~ atypical cells devoid It of' cilia were found in the bronchial tree of'. 8 percent of'the current a smoke:rs, 0.2 percent of the ex-smokers, and none of the nonsmokers: ~ TJnusual cells withi di'sintegratiing or fading nuclei were found exclu- ~ sively in 15 percent of the ex-smokers. Oral Cancer Data from the large ,Tapanese prospective study by Hirayama (37), indicate that mortality rates from cancer of the: oral cavity among males are higher in smokers than nonsmokers; A dose-response rela- tionship: was demonstrated for, tiheageat initiation of'smoking. Thestlandardized mortality ratio among cigarette smokers was 10.0 for men (P<D.001) and 1.22I for women compared to nonsmokers. These ratiosare not stable due to the few deaths that occurred from oral can- cer in thss study. Certain relationships between cigarette smoking and' cancer of the oral cavity, pharynx, and larynx were investigated by Moore (59). Over a 15-year period', 1,000 patients with invasive squamous carci'- nomaat these, sites were, treated ini Kentucky. Of thesepatient~s; 203: . had a history of cigarette smoking and had had no recurrence of cancer for a period of 3 years or more. This group was further dividedi on the basis of' current' smoking habits. Of the 122 who continued to smoke,48 (40 percent) eventuallyy developed ai second cancer at these sites,, whereas onlyfive(6 percent) of'the81 who stopped smoking de- veloped a second malignancy.. This sixfold' difference is~ statistically significant (P<0:001).. The survival curves for t!hese two groups are presented in figure 3. 74

ii ial tree ~ n lung pm had ~5 years lurrent' le non- devoid urrent iokerss exelu- Lic) in F R'ob- wit'h ~pical! ~ non- I I I . (37) long rela- I The Ifor 2ese pan- t'he F9),. Fci- 1~03 Ii,o,f, L'ed t.o ese ~e- ~y ,re Figure 3.-The survival ofl ex-smokers and continuing smokers who were treated for a primary cancer of the oral cavity, pharynx, or larynx: 100 90 80, 70 60' 30 20 10 0 4' SOURCEt NAoore„ C. (59). 5 6 7 8' 9 Follow-Up (yr) 10 L 1i 12 13 Martinez (57), studied the~relationship~between smoking in various f orms and cancer of the oral cavity in a retrospective study of 153' p,rtientlswit!h this disease. Dose-response relationships were demon- strated for the amount smoked,,the amount of' alcohol consumed~ and tiliadevelopment of cancer of the oral cavity. TyIdesley(90) examined the prevalence o£' leukoplakiai among, 402 English coal miners of whom 280 smoked and chewed tobacco. Tobacco chewing was commonly found to be a substitute for smoking in under- ground' conditions where smoking was impossible. Leukoplakia wasf found in 3.6 percent of the chew.ers,,-whereas no leukoplakia was found among the nonchewers.. Nelison and Ship (62) determined the relative influence of eight vari'ablefactorson the development of oral cancer in relation toagEat t!heonset of disease ina population, of 191 patients.rithacanfirmed diagnosis of a primary squamous cell carcinoma of the oral cavity. The factors considered inclhzded age,sex;race~,, consumption ofalco- holandl tobacco„ certain systemic diseases,and oral trauma., Thelprevalence of'heavy tobacco use was more common among the younger patients. «'hsle 91 percent of the cancer patients under the age of 45 smoked more than 20! cigarettes a day; only 59 percent of t~hepatient!s, over 65 smoked this heavily. 75' ~ K.'w

Reverse smokihgis a~ common practice in some parts of India, whereby thelh ;htedl end of a homemade cigar isheld inside the mouth. Pindborg, et al. (64) conducted an epidenriological survey of 10,169 villagers, in the Srikakulam district of south India and~ found that. 43.8 percent of those interviewed practiced reverse smoking. TLeuko•, plakia was~ found' in 818 percent of reverse smokers compared to 0:1 percent in nonsmokers. The 10 patients found to have oral cancer were all reverse smokers. Reddy, et al. (68) found that rev.erse smoking rvaspracticed by73. of 100 patients with orali cancer. Reddy,, et al. (66, 67) reported characteristic histologic findings of' the oral' cavity in biopsies obtained from reverse smokers. In two other studies from India, changes in the ultrastructure of the oral' mucosa of chewers (5h), and smokers (G5) are described'. Cancer~ ofl' the~ Esophagus In the Japanese prospective study, Hirayama (3'7) reported that ~ ~ male smokers had' a mortality ratio for cancer of the esophagus of 2.24 compared to nonsmokers (P<0:001)'.. NTartinez (57) studied the relationshipbetween smoking in various, forms~ and the development of cancer of' the esophagus in a retrospective study of 179 patients. ~ Dose-response relationships were demonstrated for the amount smoked and alcohol consumption and! t3i~edeWel'opment of cancer of the esophagus. Cancer Qf' the Larynx The mortality ratios for cancer of the larynx in the large,Japanese prospective study were reported by Hirayama (37) to be 11.0 for male cigarette smokers and 9.0' for femalie cigarette smokers compared to nonsmokers (P'<Q.001).Stell (85)1 concluct~ed'' aretrospectii've study of 11W patients tiv~itlii carcinoma of' the larynx. Only 13 percent of the patients were non- smokers or ex-smokers compared with 4!1 percentof'the: controls. The relativerisk ratio for heavy cigarette smokers was 3.48 compared to nonsmokers. The relative risk was 1.34 for smokers of pipes and cigars. b'Toore (59) reportedi the occurrence of second primary cancers in 203'sol:okers whoAiad been surgically treated forcancer r oftheoralf cavi~ty;pharynx,orlarynx,,witkout recnrrencefor.a period~of'3 years. 76

yf Iindia, e mouth. bf' 10,169 tnd, that Leuko- ~d to. 0.1 cancer moking ~~ i; et ad: l cavity iEs f'rom. ~ Ihewers i I ' that, ~u~s' of 0 the ~ment xentsi ioked f the i nese, nale 1~ to. ¢ith~ ion- rhe red, nd «'i'tttin an aiverage~followup; period of'7~ years, 40~ pereent'~of t'he~ 122'. l,atieirts who continued to smoke developed second primary cancers „f t i,E.~ uhper~ respi~ratory or digestive~~ tract, but only~ 6~ percent, of the l,utirtits who stopped smoking developed second cancers. A total of :,oi l,utients «•ith cancer of'the larynx underwent lar3~•ngectomy. Of tl~t, ~ 16 «1'lo~ contli'ntied t~o~~ smoke,~ t'~ltree~ developed a second' cancer,~ wiu,reas, ~ none of the~ 34: ' ex-smokers~ without a larynx : developed a. -,,cor id primary malignancy.. Cancer, of Uhe Pancreas I I'iray.ama (37) reported a~ significant association between cigarette =m0king~andlthe~~develbpment~of'cancer of the~pancreas~, The~~mortality n,itios were 2.05 (PC0,001) for men and 1.91 (P<0.05) for women.. Krain (~,47')~ reviewed a number~ of~ environmental factors~that may~ lbr associated with the~~ 15~~ percenti~ annua~t increase~~ in~ the death rate f roni cancer of' the pancreas~ found in the Uhit~ed States. The strongest , n~<I~ociations~ appeared to~ be~ with cigarette smoking and certain „(Tupationali exposures.. Cancer of the Kidney andl Urinary Bladder Hlirayama (37) reported a mortality ratio of 2:71 f'or cancer off thekidneyand bIdder in women whosmokecigaretties(P<0:001,)~.The mortaIity ratio of 1.07 for men who smoked; compared' to non- smokers was not significant';,however; the fe.v deaths from this cancer atnongmen in theJapanese! study did not allow conclusions to: be dra~wn. Hoover and Cole (39) examined the strength of the associ'ation between cigarette smoking and': the development of bladder cancer in successive birth. cohorts of' men and «omen, in the United States, Denmark, F.ngland'y and Wales. Increasingrates, of bladder cancer wer.e observed in populations characterized by an increase in cigarette smoking among successive birth, cohorts.. The association was con, sistent in both men andl women, andl wasalsoconsistentf'or diffierent national'ities and urban and rural groups. These findings suggest aa causal role for cigarette smoking, in the desxelopment of bladder cancer: Iln a retrospective study from Germany, Fischer (27)examined thesni:okinghabi'tsof1,02 men with bladder cancer and a controLgroup of 198' men who had benign prostatichypertrophy.Ti'herelative risk 77

, ratio was 6.4 for smokers of fewer than 15' cigarettes a day, andl 27.5 for smokers using more than this amount. Only 3 percent of' the men~ ~ with bladder cancer were nonsmokers.. ~ Xipell~ (1Q3~~)studied renal nodules~ in 2~5Q~patients~ in AustralM who came to autopsy. Benign adenomas were the: niost common 1'esions f' and were found in 22 percent of the patients: The remaining nodules ~ were cysts, thrombosed veins, abscesses,, granulomas; and metastatic ~' lesions. A, statistically significant difllerence~ between the smoking habits'of those with adenomas and those with the miscellaneous lesions z ~! was~~ reported (P<0:012)1. All the adenomas were~ found in smokers. C~ole,~ et~ al. MY conducted a retrospective~~ study of~ 461 persons~ ~ with transitional or squamous cell carcinoma of the lower urinary ; tract., After the~~ data were~ controllled~: for cigaret'~te~ smoking, occupa~-~ tional exposure appeared to contribute to M percent of' the lower ~. urina~ry~ tract cancer among men aged 20 to 89~ compared to the~ 39 percent attlributedl to cigarette smoki~~ng~ in n7err~ in a~ previ'ous~~~ report (15). T Werf~-Mfessing~ and K~atnl~en, (100) examined the association of' occupational exposure~~ and smoking~~ ini t~he~ development of bladd'er cancer in 346 males in the Netherlands who had' this disease. The { sm~oking~ habi~tls, of cancer~~ and cont.rol' patients in each group~ «ere~ ~ nearly ident'ical ; however, patients with, bladder cancer had a longer ` exposure to hazard'ous~~ woi•king, conditi~ons~ th:an~ di'd~ controls. Experimental Carcinogenesis Experimental~ studies, ma~inlyy in animals; have, added t~o~ an under-~ stand4ng~of! m<Rny~ of'the processes~~ia7wolved, in ~tobacco~ carcinogenesi's~~. Possible~~ mechanisms~ of~ chemical carcinogenesis were~ reviewed by Miller and Miller~ (58)~, Ryser (76)~, and Leone~ (5l). Electroni spin resonance studies of carcinogenesis were reviewedl by Swartiz (87). Franke (28) discussed the posible rolle of hydrophobic interactions of~ polycyclic aromatie~~ hydrocarbons~ with, protein in~ chemical car- cinogenesis. Chemical carcinogenesis in Sy~~rianihamsters~wa~s,~revietiv.edl by Shubik (82) and'$omburger (38).. Re:spiratory Tract Carcinageneais E~pidemiological~~ cli~nical, and au~~tlopsy~ data from studnes~ of~~huma~~ns have established cigarette smoking as the major cause of lung cancer in the j'nited States. One: ofl the~ reasons~ it~ has~ not~ been possible~~ to 78

lia who lesions aodules ,astatic noking lesions iokers. ersons rinary ~cupa- !lower lie 39 . ioious ler- sis. by y'in. 7). ins lr -d rliaracterize fully the mechanisms responsible for this causal relation- ~k, iE> is the lack of an ideal anian.al model in,%vhi:ch to study respiratory t~ract~~carcinogenesis~in the laboratory. Exposing~~ animalsAo cigarette~ anokc~ in a closed chamber d'oes not~ repTica~te~ the~ kinds of~~ ex~~posure~~ .ru0l-ing ~ humans~ recei.-e,, although sorne~ recently dieveloped smoking , dr:mibers provide conditions similar to the exposure experienced by Iiuiiran smokers. 1Tany animals are obligatory nose breathers and,. irr tlrem. a large~ horti~on of tlli~e~ partienla~te~ phase~ of cigarette~ smoke ~ nri' V he removed by~ turbulent precipitation ioi~~ tiLe~ na~~sa~~U passages~ or l,I rN-nt: before reaching the sites~ in the lung, most c.ommonly~~ exposed irI liumans. ~V~uerbachy, et a1L (3~)~ first demonstrated that~ malignant~ liing tuai~lors~could be produce& in smokinh, d~ogs~w~ho «-ere~~ taught to~ ~runke through a, traeheostomEi. Severa~l investigators have~~ recently ,~xuuriiiried respiratory tract ca~rcinogenesis~ in aniinals~~ using~ intra- tr;i(•l'ie;rllinstilhiti~ons~of~chemiial carcinogens found in cigarette~smoke, irucludtinb benzo~~(a)pyrene~ and! 7H-di~benz~(dl,g)carbazole~. Tumors~ re,rilting from this type: of treatment are~ freduently ~ simila~r~~ to~ lun:g nuriors found in humans (wl~ 32. 33. 36, 77. 8l1).. H~arris,, et all, (33~)~ examined the~~ acute ultrastructural effects of herrio(a)~py,rene~ carripd~ oni ferric oxide particles, ~ on the~ tracheo~- !')r()uclniall epithelium~ of t~he~ Syrian Go~lden hamster. Test su~~bstances, . were adaninistered by intratracheal instillation. Fe.rri~c, ox~~idie~ alone rt"sultedl in some~ focal replacement of' columnar~ epitheliilm~ with laol,'.-gonal basal cells. This~ effect w~as~ reversed by t,erm~iinati~on of th:e~~ treatment: Aftler treatment with benzo(a)pyrene and ferric oxide, t:ncal replacement of the columnar cells with pleomorphic cells oc- 1,rrrredi These pleomorphic cell's~~ lcadl the~ ultrastructui:al f'eatures~ of' rtY~pica~l sq~uansous cells~,ancfi. were siiYlilar~ to~ t,he~ hy~~perplasti~c~epitlreli'al '-cl~ls~ described' in the~ bronchi of smoking , dogs and the~ neoplastic~ ,~lliuaanous eells~ found in human bronchogenic ca-rcinoma.. In an extension of this study, Harris,~ et al. (~32)~ reported that vita- nrin A deficiencY or~ the~ application of lienzo~~(a)pyrene~-f'erric ox~~i'de~ tiirourh ilitratraclieal! inctillation resulted in-squ~annous met~aplasia of tlie~ trachea. I3oth lesions~ appeared to~~ be~ morpliologicaldy~ similar~ by liglit naicroscol>tir,~ but~ at~ the ultrastructura~ll level si~,*nihcant d'iffer- 4~nces Ive~re~ observed. Squamous nnet<aplasia induced~ by benzo(a),py- rene-fcrric oside~ was~ characterized by~ defects~~ in tlhe~ basement me.ml5rane; enlarged nuclei with cy~t~~oplasmic invaginations, and pleomo~rphi'c~nuclcoli not~ seen followii<zg~vitamin A deficiency~.. Sellak~u~ma~r~ and S'hubik~ (~80)' treated' Golden Syriani hamsters w~ith~ %1:~eekly intr,ltracheall instiillationsof~ 7H-dibenz~(c,g)~carbaz~ole~~ (7iH1- UI3(')~~ suspend'ed with equal amounts~~ of~ ferric oxide~in~ a saline~ solu-~ ti~on. Une group ofl 35 hamsters was treated with 45 mr~. of' the~ Carcino~r;en and a second group was~ treated w~ith~ 15~~ mg: llore~ than ~s~'-) percent of~ the a~~ainra.Is~ in each group developed respiratlory~ tract. 79

tumors. Most of the tumors occurred in the major airways andi were;' single~ and' rnnltiple~ applications. A single administration of~~ 37.5 mg., ous concentrations of benzo(a)pyrene and ferric oxidW were used in~ , Saffintti,,et al. (7'7')~ eramined, the careinogeni'c~ effects of benzo (a) I pyrene prepared as~ a~ suspensioni of fi'ne~ crystal2ine: particles at- ~`,i tached t'o~ ferric~ oxide in a physiologic saline~~ solution and admimQs~ tered kiy~~ intratracheal applications to~ Syrian Golden hamsters, Vari were found less frequently. squa:mous cell carcinomas. Adenocarcinomas and anaplastic c.arcino~nas ofbenzo(a)py.rene, witli12.5 mg. of ferricoxideresulled in five broncTiogenic carcinomas and five histologically benign respiratory tumors in a total of 61 hamsters. Following multiple adn-vinistrations,, bronchogenic carcinomas inchtd'ing anaplasticandisquamouscell types were induced i ~ all dosage ~ groups and' a~ positive dose~-re~sponse~ rela- tionslii'p~~ was~ demonstrated. Feron (24)~ studied respiratory tract tumors~~ in S'yrian~~ Golden hamsters folloiving, tracheal instillati~ons~ of fizrfurall and/or benzo,(a), hy'rene. Of the 62' hamsters. 41 developed respiratory tract tumors of which squamous cell car.ci'noma, of the trachea wast~hemost freq,u~entt type observed: Fiarfurall it, combination with benzo ( a) pyrene resulted in a hinheryieldr of tumors than was seen with benzo (a)pyrenealbne. Furfural albne possessedd no carcinogenic activity. Shabad (8Z): andl oneof'his, _ col2aborators,. Y''anysheva,, produced benign and malignant epidermoid lung tumors inratsfollotivi~ngsinglea11d muiltip1Je administrationsof' benzo(a)pyrene byintra- t'racheal instillation. Dose-response relationshipswere demonstrated: E~'xperiments in Mice Cigarette smoke~~ condensate (CSC~)~,, various fractions of CSC, and, many chemical compoun& identified in CSC~ have been tested f4r~ tumorigenic activity~ in mice by~ aa variety of' methods,~ includi~ng~ skinn pa~inting~~ and snpcutaneoir:- inj~ectioirs. Complete~ carci~nogens~~ and in- complete~ carcinogens,, which i~~ncl'ude~ tumor initiators, tumor~ pro~-~ uioters, and tumor accelerators have been described. Several' recent.t studies~ h<nre~ been conducted using mice~ as~ tlhe~ eaperimental' animal which examine~ furt~her~ the~ mechanisms involved' in tobacco carcino-~ genesis.. T.ee~ and O'NeiIl (50)~ nleasurecl the, effect of duration~~ andi dosage of~ benzo (a) pyrene applicationson~ the rate~ of~ dev.e:lopnient~ of~ benign and malignant skin ttmiors~ in m~ire: 'Z'he~ incidence rate for tumor formation Nvas' d~itectlyy p~roportGonal~ to~ lioth, time~ and~ dose. q'hese~ data conf'ormedl quite~ closcly~~ to postulated mithematic<<I models of the rate of tumor dev elopment.. 80 ~. t ~ ' I c.

t n d were hcino~nas ~ enzo (a) tles at- dininis- s'. Vari- used in 7.5 mg; in 6r,eiratory ations, , 1 types e rela- t l'olden ,zo ( a) ors of' quent tulted' ilone. iluced' wi ng ntra, 6ited. land for >kin in- )ro- ;e.nt na1' no- tge gil ,or se of' I)ii~~-ies aiid «"hitehea.d (17) studiedi the effect of altering the "tar" ;iudi nicotine ratio of cigarettes on experimental carcinogenesis. No. ~i_nuiticaut difference in tumor yield was found between condensates 4)k,i;cined fronr the smoke of cigarettes containing 16.6 mg, "tar" and nig.~ nicotline and other cigarettes~ cvntaining~~ 10:0~~ ing:, "tar"~ andl 1~.a I~n1(r. nicotine.. '-~everal studies by Bock,,et al. (7, 8, 9) have examined the tumor prowoting- activity ofl a number of flractions~ of~ cigarette sm~oke~con-~ :iens,ite (CSC)~.~ A number of~ subfractinns~~ of the: neutral fraction ,if~ ('S(" were~tested for~tu~~rmor~ promoting~acti'vity in mice~~ pretreated %O~tli 1-1,1•3~-dimethyIbenz(n)antihracene~ as~ a tumor initiator~ (8).~ The, . niost, poTa~~r~~ subfract~ioiis~~ and the fraction: containing~~ benzo(a)Ipyrene~ «ere the most active tumor promoting fractions. In another stndy (,)). the weak acid fraction of CSC'' was found to be a very weak ('0uihl~ete~ carcinogen which probably ~ acts primarily as~ a tumor pro- inutiug~~ agent. The promoting activity depended primarily: on the nuriVolatile constituents of this fraction. ilTore recently,, B'ock, et al. reviewed the tumor~ promoting~ effects~ of CSC and extracts~ of' t~"b,u,co leaves. _V combi'nation of t~wo~ subfraetions~ of the~ tobacco~ ex-~ t ra(•ts. ~is wel2 as five majpr fractions of CSC, were foundi to have tininor promoting~ activity. Tlie~ fraction containing, the polynuclear~ ;re~otmitic~ hydrocarbons~ was~ found to~ be.~ a complete carcinogen. Tw~a. >+ii>fraetions~were~ found to~be~ strongly synergisti'c~in their~tumor~pro- u,ot~i~irg~ activity w~hen applied simultaneously to~ mouse~ skim Lazar, et al. (49) found that hy,droquinone applied to mouse skin in conj,iinction with the active fractions~ of CSC accelerated the early last.ologic changes that result from the application of "'tar" or its fractions., Van Duuren,~ et al. (97')~ have~ suggested that "'cocarcinogenesis"' be differentiated fromi "tumor~~ promotion"' defining~ "cocarcinogenesis'''~ ,ts~ tlhe~ production of ~malignant tumors by ~ t~~o~ on~ more~ agents a~pplied. simultaneously or~ alternately ~ in~ single~or~ repeated doses ta mouse~ skin and -''tumor~pr.omotion"~ as a single~ treatment with one agent foll'owed by single or~~ repeated treatment with a second agent.~ Using, these~~ defiiiiti~ons, the~ a-trthors, found severall tumor~ prom~oting, agents~ to: possesscoca~~rcinogeni'c actiivit~y..~ Roe, et al. (i:/) studied' mechanisi.ns of mouse skin carcinogenesis~ using benzo(a)~pytene~ and a~ neutral fraction of OSC applied singly or in various combinations with each, other: Skin tu¢nor~incidence~rates~ ialcreasedwitih the dose~ of applied niaterial for both~ the~ neutrall frac- tion and benzo(a)~hyrenef l~I1i'xtures~of the neut~zal~ fraction with benzo-~ ( a)~pyrene ~ (lid not act ind'ependently~ ini the production of~~ ma]lignant sk~izi~ ttuuors~ l'nut syncr-~istically;~ su(,gestiidh that some. of~ the~~ compo- nents~of the neutrail fraction act as~~cocancinorrtins~~ rather thEUi as conrl- plrt~e~carcinogens~. ar

Schmahl (78) found a direct relationship between the dosage aq duration, of subcutaneous injections of tobacco smoke condensates and! the development of sarcomas in rats. ~ Maenza, et al. (56) studied the efl'ects of a combination of nickel. subsulfide (~ i3Sz) and benzo (al) pyrene on sarcoma induction in rats. `' The interval between administration of the carcinogen andl the de-~ velopment of sarcomas was significantly shorter (IP'<0.001) ini male~ Fischer rats given injections of a combina,tion of 10 mg. of M;S'z and'T 5 mg. of' benzo (a) pyrene than in rats given either ingredient alone. ;. There appeared to be a synergistic interaction between nickell com- ~' pounds and the polycyclic aromatic hydrocarbons. ~ Healey;, et al. (34), added further refinements to a technique for v measuring, the nonspecific esterase activity of mouse ski¢xi following appli~cationsof various chemical compound's:~~°~~itlr few exceptions,, , changes in esterase activity reflected the known tumor prodbcing activity of a number, of polycyclic hydrocarbons and tobacco condensates.. ~ Sydnor, et alL (89) exaxni'ned' the effect of' an aqueous extract of' ,- cigarette smoke eondensate,on benzo(a~.)pyrene-induced sarcoma in, female Spra:gue-Dawley rats. Benzo(a)pyrene was~ injected subcu- „ taneously in various concentrations of' 12.5 µg: to 400 µg: per dose dis- ; solved in sesame oil. Injections were given on alternate days for 30 doses. The mean tumor induction time was accelerated in five of' `: seven groups given the aqueous extract of CSC' in their dirinking water. A:nimals given any benzo(a)pyre-ne eventually developed sar- ~ comas at the site of'injection. Dose-response rela:tionships were demon- strated for the concentration of benzo(a)pyrene administered. It appeared that aqueous extracts of CSC contained one or more com- ponents which functionedias cocarcinogens. Aryl Hydrocarbon Hytlroxylase (AHH) Certain of the~~ch~ernical componnds~ found in the ga~s,and particulate~ phase of cigarette smoke are absorbed through the lung or oral cavity into the general circulation. Possiblv through such absorption some chemical~: carcinogens are~ carried to~target~organs~~ not directly ~exposedl to cigarette smoke.~ S~ame~ of these chemical compound~~s~ are~ probably.~ excre~tedi unchanged while others are~ metabolized t'o~ v~ariousdegrees~ by~ enzyme~syst~ems present~in the~ liver andl many~ other tissues. Tlie~ ~ microsomal mised-function oxidases are~ key~ enzyme, systems~ for the metabolism~ of' a«id~e~ variety of chemical compound~s~~ ineluding~ the 82

of nick hinra ~ the de in ma1e~ rI3Sz an ' nt alone. Kel com~ ~ilue for' 111owing eptions, ; aducing' tobacco' ract of )ma in subcu- 'se dis. ys for ?ve of _ nki~ng d sar- ~mon- !d. It com- '•hensical carcinogens found in cigaret't'e smoke. Aryl hydroearbon. hnduoxylase(', AHH) is~ a part of the cytochrome P'-450~ containi'nguniccosomal enzyme system that is present in several tissues of humans ;1udl m~anyanimal species. The activity of this enzyme system is in-dured following exposure to the appropriate chemical stimulus. The ii N,dcoxylation ofpolycycliic liy,drocarbons~results in the detoxification id ~:oine and the, activation of others to reactive carcinogEnic forms. An understanding,ofthe role of AHH in the metabolism of chemical ir, 'i.nogens in man may help clarify some of'the mechanisms involved iut«baccocarcinogenesis. 1$ecentl'y„ several studiesexaminedl AHH :t,•c Wity in animals and man. Studies in Animals. .Sydnor; et al. (88) found that an aqueous extract of CSC adminis- tc+red in the. drinking water of rats potentiated benzo:(a)pyrene- iiicliaceA AHH actiuityinthe liver. TheliiverAHH activity was~I i;,rhtlyincreasedlbytheaqueousextract ofl OSC alone.Rondia and Gielen (75) reported that rats exposed to various levels of carbon monoxide developed a decrease in AHH activity in li'ver iirmiogenates, The reduction in AHH activity developed after 120 i1oiirs exposure to levels of carbon monoxide which prod'ucedl carboxy- heinog lobin levels belb«-. 15 percent. Welch, et al. (99) reported thatthe administ'ratli'on of benzo(a)- pvrenetopregna,nt rat& resulted in, an increase of the invitro, AHH', activity of maternal liver, placenta, and fetal liver.A twentyfold ]ii-her dose of'benzo(a)pyrene was necessary for stimulation of AHH nctivityin fetal li'verthan in the plaeentaor maternal liver. Studies in Man ulate Ivity some osed rees TI]ie the t~he. Levin, et al. (52) studied the induction ofAHH activity in human skin. Human foreskin obtained from circumcised childrenwas main- tained in~ tissue~ culture mediu~m: Exposure to~~101µ/D~T: of'benzo(a):py- rene, for 16~~hours led toi a twofold to fivefold increase in~ the activity~ of'~ AHH in the exposed skin over controll values. Whitlock, et all (101) reported the presence of AHH ini humann lymphocytes. The~~ AHH activity of lymphocytescompared torat liver~ or hanster ernbryo~ ce11's~ is relatively~ low. Treatmenti~ with~ pokeweed mitol;c,n albne, increased AHH activity about twofold. Holvever,~ aa threefold to eightfold rreater~ AHI+I~activity was~found inicells,treatedi witli the mitogen~ and benz~(a) <antlrracene~ than in resting cells. 495-028 P 0-737 83

Cell anttl'Tzssu,e Culture Studies In studies of tobacco carcinogenesis„ cigarette smoke condensate (CSC),~ subfra~ctions~~ of CSC, and individual chemical eompounds~ ~~ found in CSC~ haa-e, been adni~i~nistered to~ a variety of ~ animals~ using ~~ sereral'routes of administration. Tests on living animals are frequently "~ complicated~~ and t~~im~e~consuming. Cell and~tissuecul!t~ure~systems, offer ~~ an, alternate~ tool for the~ shid~~y of~ carcino;enesi~s~ -wliich,, in some~ in- stanees~,, is~~ relatively more ~ rapi~d' thani animal ~ test'ing~. Specific ~ enzyme ~~ systems~ and other cel!lular~ f'unctions~ can~ often be~~ st'tidiied'. in greater~ ~~ detai~l, using these~ systems. ~ Cells ~ obt~ained from a variety of ~ti~ssuesand n.~ animals can be~grown or~maintainedl in c'~ultu~re~~bottles~«-lien nourishedd with an appropriate nutritive medium in a supportive atmosphere. When these cullures are exposed to various chemical compounds; changes can occur which may range f'rom minor morphologic varia- tions to malignant transformation or cell death. Toxic effects on cell cultures must be differentiated from malignant transformation. Sev- eral stu'dies~~ liave~~ recently~ examined, the effect of' cigarette~ smoke conclensate or individual polycyclic hydrocarbons found in CSC on various cell andt'issue cult'ure~systems~.~ Benedict,, et', al. (4) studied polycyclic hydrocarbon produced cyto- toxicity, malignant transformation, and chi+omosome deformity in aa variety of~~ cell, lines~ derived from rats, hamstersY and~ human tumor, cells. The cytotoxic effect of benz~o~(a)~pyrene~ was found to~ lae~ related'' to the aryl hyelrocarboci, liydroxylase activity (AHH)~ of the given ceIl' culture. Benzo(a)pyrene was cytotoxic to fetal rat hepatocytes, but this effect was probably relftted'to the action o£ the hydroxylated' metabolite, 3'-hydroxy?benzo~(a)~pyrene,~ since th~e, cytotoxicity was~ blocked 'when t'he~ AHH~ systemi n-as~ overloaded with phenobarbital. Cell strains not possessing AHH activity showedi no cytotoxic effects from benzo(a)pyrene~ alone~;, ho«-eti=.er„ in the presence of~ fetal~ rat liepatocy~~tes possessing ~AHH ~acti<<ity; enough benzo (~a~) pyrene~ metabo-~ litles~ were! secreted into the~~ medium to~~ indkrce cytot'oxie effects~ in the normally r~esistlent, cell l~ines,~ In~ hamster~ seconda~ry~ cultures, at~ t'h~e~e chromosome leuel~~ cytot~oxicit~y~ «-as, associated «•~itlii cliromat,iidl breaks,, whereas malignant~ transformation was more~ closely~ rel~ated to aneuplbidy. Diamond ('19), studied't'h~e~metaboli~sm, of benzo~~(a)~ p'yrene~ and 7,12~- dimet'hy~lbenz(a~)~anthracene (~D-MII3'y1) iirmouse,~harnster,rat,monliey,~ and human cell cult~ures~ Metaboli~siu, of hy.drocarbonslo~ "alkali solu~~ ble''~ and"~`water solta~ble"~ dhrivatives, ~. ivas~~ measured'. Th~e~ results sug- gested gested that the~ pareut~ compounds ii-ere~ first metabolized~~ to~ "alkali extractalile~"~d'e~~rii,ati~ves~and t~lreii~to "Iwater~soluhl~e"~deriiN-ati~~%,es.~All tl.re~ cell cultures tested which were, sens~itive~ to, the g~ro%vth~-inliihi'tory~ effect's of benzo(',a~)~1>yr.euo- or Dl'fB~A were able~ to~ metabolize these~ 84

,•arcinogenic hydrocarbons~~ to~ "water soluble'"' derivatives.~ The~~ data~ MV Co~nsistent with the hypothesis that metabolism of the carci'nogen, nlq uired for (yrowth-inhibitory~or~cytatoxic effect& , -~evera1 authors~ have examined malignant transformation ini celd. 1,nltures. Inui' and! Takayama (41~)~ cultured hamster lun:g~ fibroblasts ;, nrL tlien esposedl themito~ crud'e~ cigarette~ "tar"' for a period of' 3~ hours. Between 3~~ to~~ 4K hours folliowi~ng~ this~ exposure, toxic effects of the rar''~, including cell necrosis,~ swelling;, vacuolization, and' disintegra- 6ut ofl cytoplasm were observed. The death of' 40 to 70 percent of rlw c•ells Nr~ithini 72 liou~rs~ was~ followed by~ the appearance~ of~ t~rans+~ i,)rined cell~s~AN-ltich grew ~ at rapid rates:~These~ transformed cells pro• ~ ii icedl nialignant tumors~ when inoculated in the~ cheek~ pouch of ham- -ters~. Controli cell lines produced no changes when inoculated in a~, <irnilhr fashion. In~ a similar study ~ by~ Di P~aolo,~ et al. (21), trans~formation~, of pri~- ru,try hamster cell cultures~wasindiuced by~benzo~(a)pyrene„3~-rnethyl~- 1'iu~l;uttlllrene„ or i;12~-dim:ethylbenz~(~a~)anthracene.~ Transformed cell 1 Mes were established and subsequently inoculatedl in hamsters pro- ~lncin,fr malignant tum~ors~at various sites. Characteristic cli~romosom~al~ rhaniges in~the transformed cellls~«-ers~alsod,escribedL. _1~n increase~ in proliferati~on~~ and tumor prodhxctiion rate~ of L-Strain ~ ellls ~ produ~cedl by treatment w~ith~ cigarette~ "`tar"~ was studied by~ liiai and Takayama~ (40). L-Straan~celd cultures not esposedl to~"'tar"' did not produce~ ttunors, wwn~ inoculated in~ C3H~ mice~. 'A:fter an rxposure t!olow concentrations,of' cigarette~ "tar" significant ch~anges~s occurred in the~ cultures characterized by~~ enlarged ce11s w~i'th~ vacuolated cytoplasm:, giant cell formation, and accelerated growth rates. These transformed cells, producedl tumors~~ in 70~ percent of injected C3HI Mice. -Nagata (60) treated cell culltures~ obtained from kidneys~~ of' new- ~ born mice Avith 20-methylcholanthrene in variou~s, concentrations. Con, trol! cullturesleould not be~ maintained for Iong~;~however; the~ treated cells formed two~ permanent~ cell lines which had a transformed'~ mor- phology~ and altered kasyotypes. F~pitTtelial carcinomas~~ .1 ere~ produ~cedl after~ the subcutaneou~s~ injection of these~ transformed cells i'nto~ un- conditioned newborn mice. Freeman, et~ a1L (29) isolated hamster-specifi~c~ C-ty-~pe~ RNA ~ v~i'ru~ses~ from tumors inducedl by~ cell cultures~ transforniedl by~ chemical car-~ cinogens. Cell~ cultures~ were~ prepared from~ earlti.~~~ passage hamster~ enibry.o cells~ anKl treated for 7~ days with 3!-metih~ylcholanthrene~or cer-~ tai~n~ fr.actions~ of~ cigarette~ srnoke~ condensate. Fo11owing~ treatment, niorphological~ly~ transformedl celll l~i'nes AN-ere~ isolated ai:tdl imtiirt~ainecl. Subsequent inoculation in newborn hamsters~~ produced malignant tumors~ at tlie~ sitle~ of inocuhttion. -N~eAl-~ cell liues~ were establi~shedl fromm sonie~of~the resulltine; tumons: N-o infectli'ous~~viruses~«-~ere isolated from celI lines~prior~to:iuocttlation; however.~C~-type R~~NA N-i~ruses~were iso-~ s S' WE

lated from~ tumors and from cell lines derived from tumors. The au- thors concLuded that the,chemiical treatment and activation of viruses appeared to be related events., Sivak and Van Duuren' (8-3) developed a cell' culture system thatt responded witli~ characteristic changes in cell morphology to the appli- cation of various fractions of tobacco leaf extract's. Certain dose- response characteristics were demonstrated, suggesting ai mechanism whereby various tobacco, fractions might be rapidily screened for tumor-promoting activity. Dietz and Fl!axmair (2Q)' studiedthe, toxicity of aromatic hydro carbonson normalhumani epidermal cells ini vi'tro.Pieces of adult human abdomi'nal skin were maintained' in tlissue culture medium andd exposed to3'-methylcholantihrene and' benzo (a)pyreneat, a concentra- tion of 1 µg./m1l for a periodd of' 4 days. The cultures were then kept for an additional3'monthsfollowing. exposure. No malignant transforma- tion~ oceurredl; h:owever, giant cells~ and a more disorderly pattern of'f growth .ti:ereobservedi i'mthe treated cultures «eeksearlier than silnilar changes in control cultures. Binding of PolycycZic Aydrocarbons to DNA and PNA There is evidence that some chemical carcinogens including certainn of the polycyclic hydrocarbons found' in: cigaretltle smoke condensate are~ active because: of the reaction of~ the carcinogen orr a~ reactive me~- tabolit_e~~ withi cellular m~acromolecules. Dun~can,~ et al: (23)! studied a series~ of' radioactive polycyclic~ hydrocarbons with respect to their~ metabolism and tendency~~ to bind with cel~luliir DNA and RNA in monolayer culltures, ~ of~ primary~ mouse~ embryo, cells. All the tested' hydrocar•bons~ were~ metabolized t'o~ "water soluble"~ metabolh'tes~ at approximately equal' rates. A "binding index" was caloulated' to db- tiermine the~~ binding of~ various~~ hy.drocarbons~ to~~ cellular DNA ~ and! RNA. group of hydrocarbons with a high "binding index"' con- sisted' of potent carcinogens, while another group «°ithi much lower values for the "binding index" were with but one exception non- carcinogens. Carlassare, et a~l~~, ~ (12) ~ studied the in v:ivo,bind~ing~ of ~benzo ~(~a) pyrene to~ D~,~~ A. Bonzo(a)~pyrene-3'H ~ «•as~ fed tomale~ and' female~ hTCT.i mice which were~ sacrificed after 15~~ hours. The DNA was~ extracted and purified'from tlie skin, spleen, and li'n-er: The binding of benzo(a)py` rene was greatest in tihe~ liver and somewhat less~ in the spleen and skin~., It was calculated that' the~~ average, molecular weight of DNA was.6 million and that 1 molecule of benzo(a)pyrene was bound to e~very~46~.8~~ molecules of~DNA ini the liver, suggesting~covalentl bindi~ng, of ~benzo~(ia ) ~pyre.ne t~~o~~ DNA.~ I I d ~. ~ I 86

he au- riruses p' that &'ppli- I dose- ~nism d for. ~ ydiro- adult ~ and ntra~. ~ ft for pq'rna- FP of 11i1ar tain. Pate kne- al a tieir Ited I at d'e- Ind. pn- ver un- ine jce hd! Y` Ld A ;o 9 .11Lsandrov andl Vendreliy (11) found that cigarette smoke conden, -ucc, the hexane-extracted fraction of' CSC, and benzo(a):pyrene all . uddbited,RNA synthesis inmouseskin. R?-Ni.trosamines in Tobacco, uSmoke `I'he~ largest'~number of chemica~li earciui!ogans~~ which~ have been iden- nrtiezli in cigarette smoke condensatle~ are pol~cyclic hydrocarbons. \'-nitirosanii2ie compounds known for many years to be potent car- ino_rens have produced malignant tumors in ai number of'organ sys- t~~i,.ms~ of~ a wide variet'y of~ animals. These~ compound~s~ were~ recently~ i~lhtttifiecll in~ cigarette smoke,~ O'~nl'.~~ recentl~y liias~ an association been frnnld between exposure tio~~ hTI-nitrosamines~ and malignant tumors~ i'nn hnuians (55).~ -N~-nitrosamines are~ formed chemi~cally~ by a~ reaction of \O! and NOs or nitrites with secondary amines: The chemical pre- 4•ua•sors of'the N-nitrosami'nes have been i'd'ent'ified in ci'garette smoke ('0ndensate~ (C~SC)~ by a~~ number of investigat'ors. These, studies .vere~ reviewed by Wynder and )8-Ioffmann (102) .~ AZlore recently, Rhoades andl lishnson (;69)~ developed a method for the~ determinat'ion of hr~-nitrosa- luiales i'Zr tobacco: smoke~ condensat'e~ using, gas chromotography. Two \-nitrosamihes~ were~ found in CS'C~: one «as~ identified as N-dimethyl-~ ioitrosamine~ (D.11~~NA)~ and the~ other~ was~ believed to~, be~ N-~methyl- (+th~ylilitrosamine~ (M~~EN..~)~ (43', 70). The concentration of~ DMINA 11er cigarette~in nanograms, was~determineds in condensates~ from ex- nerimr~ntal~ cigarettes made -from single tobacco~ varieties rath~er~ than a tobacco blend. Each tobacco tested was grown in both, a lon-- :uul high-~ni'trogen soil. High-nitrogen soil'~~ conditions~ resulted in a~ ~~onsid~erable~ inerease~ in nitrosamines~., A popul~r brand of nonfilter cigarettes~ was a1so tested. These~ resul~t's~ are~ presentedl in tabl~e~~ B. TABLE 2: .,V-dimetliylnitrosamine (DMNA) content' of' condensates obt~ained~ from several t~obaccos,gr~own, in~ botk "high" and~ "low"~~ nitro- gen~ soils Tobacco type Soil nlttogen DR4N,A (nano- grams per cigarette) R6bineon-____, --------- Low nitrogen----------------- 0 Cattertlon_____. -------------- db----------------------- 5 Bhrlev----- --do----------------------- 3 Robinson_-___-____-_ 1"•Iigh nitrogen----------------- 27 Cattiertom____________ ------------ do----------------------- 60! Bitrley -------------- ------------ do----------------------- 140 II.S'1 nonfilter--___,___ 8'. Source:,Jbhnson, ID. E., Rhoades, J. W. (4$), 0' 87 ~ ~ W f~

Summary of Recent Cancer Findings In addation to the summary presentedl in the introduction of'th2s' chapter, based on previous~reports of the health consequences'of smok- ing, the following statements are made to emphasize the recent devel- opments in the field :. 1. Recent epidemiological, andl autopsystudies from several coun-triesconffrmth<2t cigarette snioking"isthemagor cause of lung' cancer. 2. Continued cigarettesmoki'ng by patients fol9owi'ng successfull surgi~cali removal of' a~ cancer of the oral cavity, pharynx, or larynx wi'thout'tailor recurrence for a period of3yearsisasso- ciated'n°ithasignificant increase (P< 0:Q01)inith&riskof'devel~oping a~ second primary cancer of the u'pperrespiratoryor diges-tive tract compared!to similar patients who, discontinue smoking at the time of their surgery. 3.Theintratrachealadmini'stration ofcertiain polycyclic liydrocar- bons' found in cigarette smoke condensate result's in the forma- tion of' an<aplasticand sqqamons',cellcancers of theNngand re- spiratory tract in hamsters and rats.1'fany of' these tumors are histologically siinilarto the lung cancersfoundi most frequently in cigarette smokers. 4. The application of cigarette smoke condensate or polycyclic hy- drocarbons tovarious cell cu.ltures often results in transformation to cells with a more rapid and disorderly growt'h pattern. Trans- formed cell" linesfrequent'ly producebe.nign or malignant tumolrswheirtr.ansplantedtoetperimental aniina~ls.. 5. -N-nitrosamines havebeeli, identifedin cigarett'esmoke: These compounds are known to bee potent cancer causing chemicals for avarietyof'anima~ls. Theya~ppear to be formedirr higller concen- trationsfi•om tobaccos raised itndenhigJi-nitrogen soil conditions. Cancer Refierences. (1) ALExANDROV, K., VErroERLx, C. Action de condensats de fumee du tabac sur la synt'hese de R_\A dans Ia peau des souris. (Action of tobacco smoke condensate oni the synthesis of RNA in mouse skin.) Chemieo- Biological Interactions -1(3 ) : 1.55;-161, February 1972. (2.). AUERBACH, 0., IIAJSIIOND,. E. C., GABFINKEL, Ii, El)ltheliAll changes'S lnn e%~-cigarette smokers; Cancer Cytology 11i(1) :5-12;,1n71. (3Y AUESeaCfr, O:, HAuUMoso, E. ('., IiiaMAV, D:, GAxFINKEL, L. Effects of cigarette smoking on dogs. II. Pulmonary neok1asms: Archives of' En- vironmental, Health 21 (;6) :754--7CkR;,December 1970i. 88

I ( BE:rEDIOT, W'. F:, GIEr.EN, J~ E., NEBERT, D. W. Polcyclic hydrocarbon- I f' this produced toxicits, transformation, andi chromosomal aberrations as a function ofl aryl hydrocarbon hydroxylase activity in: cell cultures. InternationalJournalof'~Cancer9(2) : 435-451, Mar.5,1972. omok- level- I (5) BERC; Jl W:,, SCxarrIENF-ErD, D:,, RITrER,F. Inci'denceof' multiple primaryy cancers. III. Cancers of the respiratory and upper digestive system as multiple primary cancers. Journal of the National, Cancer Instit'ute. , 44(2) : 263-274, February 1970. 'oun- (6) BERRY, G.,, Nr".w$ousE, M. L., TuROK, M. Combined effect of asbestoss ;lung exposure and smokiing on mortality from lung cancer in factory workers. Lancet 2'(7775) ' : 476-47 9, Sept. 2, 1972. SsfLi1 (7) Bocx,,F: G. Tumor promoters in tobacco and cigarette-smoke condensate. 1, or Journal of the National Cancer Iinstitute 48(6) : 184'9-1553;, June 1972. 1 (1b) BoaK, F:,G.,,SsvAIN; A. P:,,STEDNCAN, R. L. Composition studies on tobacco. 4SSor we1- NLI: Carcinogenesis assay of subfractions of the neutraU fraction of cigarette smoke condensate: Journal of' the National Cancer Institute (geS, 44(6) : 1305-1310',, June 1970. (9): Bocx, F. XLIV. G.,, SWAIN, A. P., STEDacAN, R. L. Compositionistudies on tobacco. Tumor promoting activity of subfractions of the weak acid II fraction of cigarette, smoke condensate. Journal of the Nationall Cancer car- a- re- are. ~tily i ClY- ion k15- brs Institute 47('2) :4'29-436„Augnst,1971.(10.), BO'rr¢cEIELI.I„ R., DEI:NERr,. E., MosANaHINI, 0. Rapporti tra carcinoma, broncopolYnonare primitivo e fumo di tabacco. (Relationship between primary bronchopulmonary, carcinoma and tobacco smoking. ) 14IGnerva IlTedica Giuliana 90) : 289-291, November-December 1969. (II'), BOUCOT,, K. R.,, WEISS, W.,, SEIDMAN, H., CiARNAHAN,. W., J., C00PER, D:, A. The Philadelphia pulmonary neoplasm research project : Basic risk factors of lung cancer in older men. American Journal of Epidemiology 95 (1i) : 4-16. Januars 1972: (12) CARLASSARE, F., ANTONELDO;, C.,BACCICH,errl,. F.,, :4iAIFER, P. Onthe binding of benz(a)pyrene to DNA "in vivo". Zeitschrift fur Natur- forschung 27 (2) : 200-202, February 1972. (13) CARRADA BRAvo, T., NUNEZ JARQuIN, E. El diagnostico roentgenologico de las neoplasias bronchopulmonares primarias. (Reoentgenological diagnosis of primary bronchoplumonary neoplasms. ) Revista Mexicana de Radiologia 25 (5) : 1$5--196, September-October 1971. (11y) CoLE, P., HoovER;, Rl, FRIEDELi„ G, H. Occupation andl cancer of'the lower urinary tract. Cancer 291(5) : 1250-1260,, May 1972. (15)' Cor.E,, P., MoNSON, R. R., HANINO, HL, FRIEDEa.r, G. Hs Smoking, and cancer of the lower urinary tractl New England, Journal of Medicine 284(3') : 129-134,,Jan. 21,1971. (16) CRAOC, J. Lung cancer in Jersey: Its incidence and associated biochem- istrr. British Journal of' Clinical Practice 25'($) : 3G4}-3!6:i, August 1971. (17) DAVIES, R'. F., W'HITEIiEAD, J. K. A study of' the effects of' altering, the tar/nicotine ratio in experimental tobacco carcinogenesis. British. Journal ofCancer24(1) : 191-194, Mareh1 1970. (l8) DELARIIE, N. C., AIIDERSONy. W.,. SANDERS, D., STARR,. Jl BroDchlolbalR'.eolar' carcinomaL , A reappraisal after 24 years. Cancer 29(1) : 90-97, Janu- ars1972. (19:), D7AMotiD, L. JTetnbolism, of' polycsclfi.ch;vdrocarbons in mammalian cel'll cultures. International Journal' of Cancer 8(3'),: 451-462, 11iov.,15, 1971. (20)DiETZ, M~ II., Ft,AxaiAN,, B! A. Toxicit'y of' aromatic hydrocarbons on normali human epidermal cellb in vitro:, ('nace,rResearch 31(9) : 1206-120&, September 1971. 89

(21) DrPAoI:o, J. A., NELSON4 R. L., DONOVAN, P: JL Morphological; oncogenic, and karsolbgical characteristics of Syrian hamster embrfo cells trans- formed in vitro by carcinogenic polScyclic hydrocarbons,, Cancer Re- search 31(8) : 1118-11'27, August 1971. (22) DOLL,, R., PrKE, !L C. Trends in mortality among British doctors in re- lation to their smoking habits. Journall of the Royal College of' P'hysicians'.6'(2) 1: 216-222', January 1972. (23) DUNCAN, M., BeoaKES, P., DiPPnE, A. 3ietabolism and bind!ing to cellular macromolecules of a series of hydrocarbons by mouse embyro cells in. culture. International Journal of! Cancer 4(6),: 813-819, Nov. 15;, 1969: (24) FEROw, V. J. Respiratory tract t'umors: in hamsters after intratracheal instillations of'benzo (a) pSrene alone and witihifurfhlral. Caneer Research 32(1) : 28-36, January 1972'. (25) FERSARa„F: A. Ecolbgical analysis of'lung cancer in the city of La' Plata. In': Englund, H. 1T.,, Berry, W. T. ( Editors. ) Proceedings of! the Second International Cliean, Air Congress, Washington, D.C., Dec. 6i-11, 19701 Nevv'York„Academic Press,197'1, pp. 244-247. (26) FIrraERLAND, A., HuseK, T., BENDLOVA, J: Contributionito the investigation of the effect of cigarette smoking. S6ornik, Vedeckych, Praci' Lekarske. Fakulty Karlovy University v Hradcil Kralove 14(2) : 221-234, 19711 (27) FrsaxER, G. Rauchgewahnheiten und Blasentumoren. Eine klinische U'n- tersuehung. (Stnoking' habits and bladder tumors. A clinical study.) Zeitschrif't fur Urologie' und Nephrologie 64 (4), : 271'~-274,, April 1971. (28) FRANR•E, R. The' possible role of' hydrophobic interactions of' polycyclic aromat.ir'h5drocarbous with protein in:chemical careinogenesis. 1Talecu+ lar Pharmacology 5(6) : 640-6:i7, \'ovember 1969. (29) FREE]fAN, A.h7.,KELLOFF, G. JI,.GILDEN, R. V., LA'PTE,W. T....SM1KAIN, A. P.,. HuEBNER, R. J. Activation and isolation of hamster-specific'C-tSpe RNA viruses from tumors inducedl by cell cultures transformed' by chemical carcinogens. Proceedings of'the National Acadenly of Sciences (USA) 6'8('10):: 2386-2390; October 1971. (30) FuRNICA, G., TOADER, M. Continutul de z1OPo in diferite sorturi de tigari. (PoaOcontentl in different cigaretteblends.)Ilgiena 18!(8): 469-474, August 1969. (31) HA.IDU, S. I., Huvos, A. G'., GooDNER, J. T., FooTE,, F. W., Jr.,, BEAME, E. J., Jr., Carcinoma of the trachea. Clinicopatholog'ie study of 41 cases. Cancer 25(6) :~1448-1456; June 1970. (3`L) HARRI9,,C. C., .ry, PORWI,,:1'T. B:,. KAUFMAN, D. G., SMITH, J. M., JACKSON, F. E:,. SAFFIOTTI, l.J..I1.istiogeneSls.Of. sflllamousmetaplaSiainthe hamster'tra- cheal epithelium ~ caused by vitamin A deficiency or benzo (ia ) p;Frene-ferric oxide. Journalloft'lleNat9onal Cancer Inst9t'ute4'8~('3)~: 743-747, March. 1972. (:T3). HARRI6y C. C:,, SPORN, 2%IL. B'.,. KAUFMAN, D.. G!, S1'fITIr,. J. 'M.,. BAKER,. 111. , S.,SAFFroTTI, U. Acute ultrastructural effects of benzo(a)pyrene and'ferriic oxide on the hamster tracheobronehial epithelium. Cancer Researeh, 31(12) : 1977-1981, Decetnher 1971. (34)~ HEALEY, P:,. MAWDESLEY-THOMAS, L. E.,., BAHRY,D'.. H.. The' effectl of sOmee polycyclic hydrocarbons and, tobacco condensates omnonspeciflc esterasee activity in sebaceou5glanrdsof mouse'skin. Journal, ofPathol~ogp105(2) :147-152; October 1971. (35) FI>:RROLD, K. McD. Survey of histologic types of' primary lung' cancer in, ULS. veterans. Pathology Annual 7: 45-79; 1972. 90

Fenic; tansr I Re- ~ re- ~ of lalar ~S in ;9fi9. heali rrch i ata• ond! 9Z0: ion. ~`ske B., ~a- 'ic ch le ie n Iln;Ao, F., FuJISawa; T.,, Tsusuas, E., YansaMunA, Y. Experimentnll cancer of' the lung in rabbits induced by chemical carcinogens. Cancer Research 32(6) : 1209-1213;,June 1972. 1.t7) HiaAYaNrA, T. Smoking in relation to the death rates of'~ 265;118 men and! women in Japan, A report of' 5 years of' followupj , Presented at the American Cancer Society's Fourteenth Science Writers' Seminar, Clear- w,ater'Beach, Fla., Mar. 27, 1972, 15'pp. ;8) I3oasuxGES„ F. Chemical carcinogenesis in, Syrian hamsters. Ins I3om- burger, F: (Editor). Progress in Experimental Tumor Research. Path- ology oftheSyrian, Idamster: Vol. 16,, Basel, S. Karger, 1972, pp. 152-175. „U I, HOOVER, R.,, CoLF., P'. Population trends in cigarette smoking and bladder cancer. American~ Journal of Epidemiology 94(5) : 409-418, November 1971!, ioJ INui, N.,, TAnAYawcg, S! Acceleration of proliferatibn and, tumor produc- tion of rate of L-strain cells by treatment with ciga:rette tar. G'ann 62(4'.) : 315-320,August 1971. ~ fl) Ivua,, N., TaKArAnse, S. Effect of'~ cigarette tar upon~ ti'ssue, cul'taurecells, Neoplastic transformationi of'liannster lung cells by tobacco tar in tissue culture: British Journal' of Cancer 25(3)': 574-583, September 1971. u.1,?) IvaKmNo; G. I. 0 rolilkureniya v zabolevayemosti rakom legkogo. (Role of smoking, in, the incidence of lnng, eancer. )Vrachebnoe Delb 9: ~ 99-101;. 1971. (.+3) Jbnnso.N, D. E., B:HOAnES, J. W. N-nitrosamines in smoke condensate from several varieties of' tobacco,, Journal of the National Cancer Institute 481(6) : 1845-1847;, June:1972: JoYErr, G. The thorium-series in cigarettes and in,lungs of' smokers. Experi- entia 27 (1)~ : 85-89,,Jan. 15;,1971., i5) KeNvEnY,, A. Lung, cancer in young adults. British Journali of'~ Diseases oftheChest66'(2')~:147r154, April 1972. ( ~fi) KoszasowsKZ, T. 0 raku pluca-po 25 latach. (Lung; cancer in, the course of 25' years.) Pollikil Tygodhik Lekarskil 26(47) : 1805-1807, Nov. 22, 1971. i!F7) Kxaiv, L. S. Crossing of the mortality curves for stomach and pancreatic carcinoma. International Strrgery 57(4) : 307-310;,Apri11972. (~8) LAassoN, S. A;Idersspeciflk incidens av prinrar lungcancer i sverige. Trenden under periodeu 1959-66. (Age specific incidence of lung cancer in Sweden. The trend during the period 1959-66.) Lakartidningen 68(38) :, 4229- 4236; Sept. 15,1971'. (.~9) LAZAR, P., IzARn, C., _1TossiE-TESTA, J., CriouaounrNaov, I. Interaction entlre 1'liydroquinone et le condesat,de fumee de cigarette dans les tests eutanes a court terme du pouvoi'r carcinogene. (Interaction betweenn hydroquinone and cigarette smoke condensate in short-term skin tlests of! carCinogenicactivity.) Coniptes Rendus Hebdomadaires des Seances de l':>;•cademie des Sciences ; D: Sciences N aturelles 274 :-19('i-49:), Jan. 17,, 1972. (,50)! LEE, P. N., O'tiEiLL, J. A. The effect both of time and dose applied on tu- inour incidence rate in benzopyrene skin painting experiments. British Jlournal of'~ Cancer25'(~4) : 759:-77.0, December1197.1. (51)LeoNE, G. linportanza del ftittorii ambientalinella patogenesi dei t'~umori, dell' uomo. Ruolo dell fumo di sigaretta, (lmportanceof environmental . Eactorsin thepathogenesis of tumors i~n, man. The role of cigarette smoking.) 'Minerva Jlediiea. 62(49) : 2461-?.480,, June 20, 1971. 91'

(5`Z). LEVIN',W., 'G`ONNEY,.A. H., ALVARES,.A..P:,,jIERKATZ, L, KAPPAS, A. I71duc,~ tion of benzo(a) porene hydrox5lhse in llumani skin. Science 176, (4033) 419-420; Apr. 28,1972: (53), LuxDIN, F. E., Jr., WAGONER, J. K., ARCxER. V. F.. Radon daughter expa v sure and respiratory cancer quantitative and temporal aspects. National ` Instilt'uteforOccupationallSafety andHealth,NationalInstituteofEn=• viromental'Ilealt'h Stiences, Joint Monograph No. 1,:1971~ 177 pp: (54) LuTaRA, U. K.,, WooDS;, D. A., WAIIi, P. N., GIrPTA, M. Ultrastruoture of human oral mucosa after prolonged exposure to tobacco. Indiani Journab of Medical Research 59(11), :15i7-162, Jan. 1, 1971. (55)! ;1TcGLASaRN, N . D., WALTERS, C. II..,, JYcLEAw, A. E. \h Nitrosamines in African alcoholic spirits and oesophageall cancer.. Lancet 2:',1017, Nov. 9; 196& (56), riTaENZA, R. M., PRADaAN, A. D1.,St7vDExMAN, F. `R.,, Jr. Rapid induction of sarcomas in rats by combination of' nickel sulfide andl 3,4'-benzpyrene: Cancer Research 3'1(12) : 2067-2071. December 1971. (57) MaKrINEz, I. Retrospective and' prospective study of careinoma, of the, esophagus,,moutli, and pharynx in Puerto Rirn. Bnletinide la Asociacion Medica de Puerto Rico 62(6), : 170-178, June 1970! (58) lliLtER, J: A., McI:I:ER; FJ, C. Chemic•a:l carcinogenesis: Mechanisms andd approaches to its control. (Editorial.) Journal of the National Cancer Institute 47(3) : v-xiv, September 1971., (59) 111ooRE, C. Cigarettie smoking and'cancer of the mouth, pharynx, and larynx. A continuing study. Journal of the American Medical Association 218 (4) ~: 553-558,, Och 25, 1971. (60) NAGATA, T: Malignant transformation of' mouse kidney cells in vitro bs 20-methylcholanthrene: bledical Journal of Shinshu' University 15(3:) : 131-151, October 1970. (I61). NATIONAL ACADESIY OESCIE:V'GES. 1'articulate Polycyc1:iC Organic Matter. BioIogic' Effects of Atmospheric Polluta:nts; Committee on Biologic Ef- fect's ofA'tmosphericPoll~utants, Divi'sionofhledical Scienees, National Researchi Council, Washington, 1972.3611 pp. (;6,2)! NELSON;, J': F., Sclie, IL I. Intraoral c•arci'noma : I'redispo,ing factors andd their frequency of' incidence as related to age at~ onset:. Journal of the American Dental Association 82'(3) : 564-568, March 1971. (63) Ni'xOLOVA„ M.1'E. Ra<lioaktix•nyti• faktor tabachnogp dn-ma: (Radioactive factors in tobacco smoke:), Gigienai i Sanitariia 35(8) : 89-93. August 1970. (61/,) PINDBORG, J.,J.,, `I!EIITA,. F., S., GUPTA, I'.. L~.. DAETARY, D. K., S3fIT.II'., C. J. Reverse smoking in Andhra PradeSh, India : A study of palatal lesions among 10,169 villagers. British Journal of Cancer 250) : 10-20, March, 1971. (65). PI:AOKOVA, A., SIEDAK,, H.,, MEYER, J~. WATERTI4IISE,. J. P. Ultrastructnre'e of:surface cells of the oralJmucosa. Folia \Iorphologica 1i9('2) : 165-170, 1971. (66) R'EDDY„ C. R,. R'. M., Iiaa'IESwaRI. V. RI., RAscLu,, C., Rz=ijDy, I':, G. Il;isto- pathologiical' study of stomatitis nicotina. British Journal of' Cancer 25( 3) : 403-410; September 1971. (67) REDDY„ C. R. R. M., RAJU, 17. V. y;. RA.'IULU: C:, REDDY, P. G. Changesilnthe ducts of' the glands of'the hard palate in reverse srnokers. Cancer 30 (1): : 231-238, J u1y 1972. (16<4)RF.DDY, C..R.R: ~X, SEKII:4R. C1..RA'JII, M. V. S., RIEDDY,,.13. S+,KA'\1ESWARI', V. R. Relation of reverse smok,ing, to carcinoDia, of thehzTrdpalate. I'n- di'an Journal of Cancer 8'(4):'?Gd'-268, December'1J71. 92:

~ ezpo- ltional 6f' En- I pre of Purnal les: ini tov: 9, lter. I Ef, bna1. And the i ~ive fust ~ I J, pns hch are 70,, to- !er in er i 0;:+ 1 RaoADES,, J. W., JoHrrsoN, D:, E. Method for the determination, of' N-nitro- samines in tobaco smoke condensate. Journal of the National Cancer Institute 48(6) : 1841-1843i June 1972: ;0) RHOADES, J. W., JOHNSON, D. E. N-dimethvlnitrasamine in tobacco smoke condensate. Nature 236(5345) : 307-308, Apr. 7, 1972. ?I ) RicxARD; `'., D., SAMPSON, C: C: Incidence of bronchogenic carcinoma, in Negroes. Statistical analysis of 94 cases. Journal of the National Med- ical Association 63(1) : L0-12'; January 1971. ?.' ) RoBSINS, W. T. Bronchial epithelium in cigarette smoking college students: Journal ofl theAmericam College Health Association 20(3!)~: 209-211, February 1972. RODI2IGL?EZRYriTERA„ L.,. AcI-ION PoI:II.AJI:US,, a1.,, RODRIGUFy SII.vA, H., DE LAPAZ;, E.,. PITA. DE LA VEGA,H.,, DU6AIVD. OCIGAM'ENDI, R:,. SOLLET. GUILARTE, R. Habito de fumar y diagnostico at alta. Estudio de 453 casos. (Analysis of the smoking habit in discharged patients. Study of 453 cases.) Revist'a Cubana de 3,ledicina 8(6) : 561-:,67', Dec. 31, 1969. ')) RoE; F. J. C), PETO, R., KEARNS, F., BISIIO[;, D. The mechanism of carcino- genesis by the neutral fraction of' cigarette smoke condensat'e. British Journal of'Cancer 24(4), :~788-806, December 1970. 75 ) RbvDIA, D~, J., GIELEN, J. Influence in vivo de 1'oxSde de carbone a faible concentration sur 1'actlivit'e de la, benzopyrenehsdroxylase et de la choles teroL-7a-hydroxylase hepatique du rat. ( In vivo influence of carbon mon- oxide at low concentrations on the activity of'~ rat liver benzo (a) pSrene- hydrox5lase and cholesterol-7a-hydroxylase.)' In: Englund: H. M., Beery, W. T: (Editurs.)~ Proceedings of the Secondi International Clear Ailr, Congress, Washington, D:C., Dec. 6-11, 1J70: New York, Academic Press, 1971, pp. 234-237. i 76): RYSER, H. J.-P. Chemical carcinogenesis, New England Journal of hiedi- ci'tie 285'(13'J : 721-734, Sept. 23, 1971.. (77). SAFFIOTTI, LT':, AIOPITEBAPTo, RS, SF.LLA.K',UDTAR, A. R., CihFI6,. F., KAUFMANyDs G. Respiratory tractl carcinegenesis in hamsters' induced by different numbers of administrations of'benzo(a)psrene and, ferric oxide. Cancer Research 32~(5) : 1073-1081, 5iay 1972: (7S)~ ScIImaFIn„ D. Quantitative Versuche an Ratten liber die carcinogene Wirksamkeit von~ Tabakrauchk',ondensaten, (Q,uantitativeinvestigationsof' careinogeniceffects of tobacco smokecondensat'es in rats.), Zeit-sehrift fiir Krebsforschung und Klinische Onkologie 76(4)',:, 320-324. 1971., (79) SbIIaIDa, W., DE LINT, J: Causes of death of'alcobolics, Quarterly Journal of Studies~onAlcoho133!(1) :175-135i March4972:. (SD), SELLAKUMAR;,A., SiILBII:; P. Carcinogenicity of 7H-dibenzo (c,g) carbazole in the respiratlory tractl of hamsters. Journal of the National Cancer'In- stitu'te48(6) : 164'1'~1646', June1972. (81) SiLABAD,, L. M. Dose response studies in experimentally induced lung tu- mours. Environmental Research 4'(-1)': 305-315, October 1971. (;b2), :illunIK; P. The use of the Sp,rianGolden hamster in chronic toxicity test- ing. Irt: H'omburger, 1!': (Editor). ProgressiuExperiment'al, Tumor Re- search. Pathology of the Syrian Hamster, Volume 16, Basel, S. Karger, 1972', pp. 176-184. (83) SIVAK, A., VAaDuunEx, B. L. A cell culture sy,stemforthe assessment of tumor-iirom~otingactiR ity. Journal of the National Cancer Dnstitute44 (5):1091-1(YJu, .\laS1070:, 93

(84) SOL:vICxA, H., BisaxoF, R: Obsah "°'Pb a""'Po v nekterych druzich Ceskob slbvenskgch cigaret. (The assay of nOPb and T1°Po in a group of Czecho+ slovakian cigarettes:) Casopis Lekaru Ceskfch 1Q9(28) : 654, July 1970. (85) STELL, P'. ST, Smoking, and' laryngeal cancer. Lancet 1(7751) : 617-618, :i1ar.18, 1972: (86)' STERZ.I.a; T. D.,, PoLLAcx, S! V. The incidence of lung cancer in the U:S.. since 1955 in reiation to the etiology of'the disease. American Journal of Public Health 62'(2) : 152-158, February 1972. (87) SwAaTZ, H. X Electron spin resonance studies of' careinogenesis: In: Klein; G:, Weinhouse, S. (Editors),. Advances in Cancer Research, Vol- ume 15, New York, Academic Press, 1972, pp. 227-252. (188)' SxDxoR, K. L., ALLEN, C., Fi LESIiER, J. W. Potentiation of' benzo (a )pSrene- induced liver enzyme activity in Sprague-Dawley female rats by aqueous extract of'cigaretlte smoke condensate. Journal of the National Cancer Institute 48(4),: 911-919, Apri11972. (89) SYDNoR, K.,L., ALLEN, C., Hiaorss; B; Effect of an aqueous extract of ciga~ rette smoke condensate on benzo(a)pyrene-ind'uced sarcoma and body weight in the rat. Journal of'the liational Cancer Institute 48(4) : 893'- 909; April 1972. (90) TYLDESLEV; W. R. Tobaeeo chewing in English coal miners: A preliminary report. British Journal of Oral Surgery 9(1) : 21'-28',,July 1971. (91) U!S: PuaLlc HEALTH SERVICE. The Health Consequences of Smoking. A Public Health Service, Review : 1967. U.S; Department of Health, Educa- tion, and Welfare. Washington, Public Health Service Publication ho: 1696; Revised January 1968, 227 pp. (92) I'JIS: PuDLIC HkALTH SERVICE. The Health Consequences of'Smoking. 1968 Supplement to the 1967 Public Health Service Review. U.S. Department' of Health, Education, and Welfare: Washington, Public Health Service Publication 1696, 1968, 117 pp.. (93) U.S. PUBLIC HEALTH SERVICE. The Healthi Consequences of Smoking; 1969, Supplement to the 1'967' Public Health Service Review. U.S. Department of' Healtih~ Education, and Welfare. Washington+ Public Health Service Publication 1696-2, 1969, 98 pp. (94) U.S. PvRLIC HEALTH SERVICE. The Health Consequences of' Smoking. A Report of'the Sllrgeon G'eneral : 1971. U.S. Department of Health, Educa- tion, and' Welfare., Washington, DHEW Publication No. (HSM) 71- 7513; 19T1, 458 pp, (95) U.S. PuRLIC HEALTH SERVICE. The Health Conseclpences of Smoking. A Report of the Surgeon General: 1972'. U.S. Department of Health, Education, and Welfare. Washington, DHEWPublicati~on No. (HSM). 72-6516, 1972, 158 pp. (96) U!S: PUBLIC HeAnTII SERVICE. Smoking and Health. Report of the Advi« sory Committee to the Surgeon Gsneralof'thePublicI$ealthService. Washington. U.S. Department of Health, Education, and Welfare, Pub- lic Health Service PuhlicationNor 1103~ 19644. 387pp.. (9'Y~): VAlYDITi7RE1V,..B. L,,BrAZEJ, T., .('i.OL'DSCFI\fIDT,.13.:CTi.,..IC9TZ, C.1,3'IFLCIIIO.N':pEy S., Slvax, A. Cocarcinogenesis studies on mouse skin and inhibition of tum~orinduction. Journal of'the Xational Cancer Institute 46(5) :1(k39-104.4,.hTay 1971. (98) WAL, A. It. V. D:. LE:vDE; IR.: VAN DEx. Cara rookgewoentPn en bronchus carcinnom. (Chronicnonspecifie ltrng disease. smokine and innz cancer.) Jaarboek Kankeronderzoek enKankerbestrij'ding19;f37-436,1969;, 94'

'ko- 7ho- %19.70. r618,. I I ~ III1 S'. E~l of' In:: .Vol- [ene- eous pcer ('1()), WELCII,. R: -M., GO]'f3II, B'.,. ALVARES, A. F'.,. C41^PNEYy A. H. Dffectof enzyme induction on the metabolism of benzo('a)ipyreneand' 3-metlhyL--l-mono-methslanlinoazobenzene in thepregnant and: fetal rat. Cancer Rlesearch 3'2',(:i (5973'-978; 11ay 1972. i,l,9r )WERE--NIESSING; B. VAN nER; KAALEN, J. G. A. H. Beroepen en rook- gewoonten van Rbtiersdamse bltlascarcinoom-patienten. (Occupationss and smok5nghabits of'' blhddlercarcinomapatientsi~m Rotterdhm:), .Jaarboek Kankeronderzoek en Kankerikestrij(llig, 19:, 77-85; 1969'., 1+,1) WHITLOCK, J. P., Jr., COOPER, H, L,, Gnl:Roix, H. V. Aryl hydrocarbon (t,enzopsrene) hydrosylaseis stimulated: in human l_mnphocstesby initogens and benz(a)antllracene: Science 177 (4049) : 618-fi19: Aug:,18; 1072. 11'YNneR, E. L., HoFFMANN;, D. Tobacco and Tobacco Smoke. Studies in Experimental' C'arcinogenesis,, New York, AcademicI'ress,, 1967, 730pp: YICm:L„J.J'i. The, incidenceofe benign; renal nodules:, (A cliniocopathologicstudy: ) Journal of tinologs1I06'(-1):, 503'-506aOctober1971. I 10 j) 7.YJLSrRA, V. L. J. Roken, Iongkanher en radioactief Po"° (Smoking, lung cancer, and'razlioacti'vepoloniunr-210.)TijdlschriYt voor Sociale Genee- skunde 47(23) : 775-7v9„lov. 14, 1969.

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Contents A Page Iiltroduction-------------------------------------------- 103 Smoking and Birth Weight Epidemiological Studies Cigarette Smoking and the Low-Birth-Weight Infant- 105 Evidence for a Causal Association~ Between Cigarette Smoking and Small-for-Dates Infants------------ 106 EVidencei for~ an Indirect Association Between Cigar rette Smoking; and Small-for-Dates Infants------- 110! Experimental Studies Studies in Animals Tobacco Smoke----------------------------- 114. Nficotine----------------------------------- 115, Carbon Monoxide--------------------------- 116'. Polycyclic Hydrocarbons--------------------- 1'17 Studies in Humans Carbon Monoxide--------------------------- 118 Polycyclic Hyd'rocarbons--------------------- 119 Vitamin B12, and Cyanid'e; D'eto:xification-------- 119 Vitamin C---------------------------------- 1'19. Possible?1lechanisms--------------------------------- 114 Timing of t~heTnfluerr,ce ofC'igaret~te Smoking~ on: BirtJi~ Weight------------------------------------------- 120 r.S'ite of' Action at the Tissue and Cellular Level------------ 121 Signific¢n,ce of the: A'ssociation------------------------- 121 Birth IVei'ght Summary------------------------------- 1'2'2 Cigaret't'e Smoking and Fetal and Infant Mortality Introduction---------------------------------------- 123 Spontaneous; A.bortion'-------------------------------- 123 Spontaneous Abortion Summary------------------ 124 Stillbirth------------------------------------------- 124 St'illbirth Summary------------------------------ 125' 495-02S 0-73-8 99,

Page Cigarette Smoking and Infant Mortality-Con. Late Fetal and Neonatal Deaths------------------------ 126 Epiderniloiogical S'tudies-------------------------- 128' C~omparisons~ of t'he! Mortality Risks~ of' Losv-~ Birtli-W~eight Infants Born to Smokers and Nonsmokers------------------------------ 126 Recent Studies------------------------------ 128 Anal}-sis of'Previously Reported Studties-------- 130 Factors Which I'nfluenee~ Perinatal MortalityOt•her Than Smoking---------------------- 13'1 Experimental Studies Studies in Animals-------------------------- 132 S'tudfies in Humans-------------------------- 133 Significance:of' the Association-------------------- 133 LateFet'al and'~, Neonatal Death Summary---------- 134 Sex Ratio'---------------------------------------------- 135' Summary------------------------------------------- 135'. Congenital 1VI!alformations-------------------------------- 136' Congenital Malfor7reation Summary--------------------- 137' Lactation I'ntroduction---------------------------------------- 138 Epidemiological Studies------------------------------- 138 Experimentad' Studies--------------------------------- ' 138 Stud ies, in AnimalsNicot'ine----------------------------------- 13'8' Influence on the Lactation Process------------- 138' Presence of Nicotine in, the 1Vlilk-------------- 139 Evidence for an Effect Upon thei Nursing Off- spring ------------------------------------ 139 Nitrosamines------------------------------- 139 Studies in Hurnans Nicotine: and,ior Tobacco Smoke--------------- 139' Influence on the Lactation Proeess------------- 1'39. Presence of' Nicotine in the MiIk-------------- 140 Evidence for a Cliniical Effect Upon the Off - spring------------------------------------ 140~ Vitamin C---------------------------------- 14'1' Lactatibn; Summary'---------------------------------- ----------------- - - - - - - Preeclarnpsi'a-------------------------------------------- 142' Summary_------------------------------------------_ 142' R'eferences---------------------------------------------- 142

Page 126 126, 126 128 130, I 131 132 133 13'3 i 134 135 135'. 1' 3 6 137 l3'8 :38' 38 38' 38 39, 39 19 191 9 0 List of ~ Fngures Page Figure 1.-\Iean birth, weight for week of' gestation according to maternal smoking habit: control week singletons--------- 104~ Pi,ure 2.-Percentage distribution by birth, weight of' infants off mothers who did not smoke during pregnancy and of those Ncho smoked 1 pack of cigarettes or more per day---------- 105 Figtire 3.-Percentage of: pregnancies with infant weighing less than 2;5000 grams, by cigarette smoking category----------- 108~ Fi;ure 4.-Average birth weight by maternal smoking, habit (a) before current pregnancy and (b) during, current preg- nancy------------------------------------------------ 110 Figure 5.-Percent of'low birth «-eight white infants by smok- ing: status of'~ their motlhers------------------------------ 113' F'inure 6.-Neonatall mortal,'itu rates among, single white births in hospitals (by detailed birth weight and specified gestation groups: United States)'--------------------------------- 1128 Figure 7.-Perinatall mortality rate per 1,000, total births by cigarett~e smoking category----------------------------- 129' List of Tables Table 1.-fnfant birth weight by maternal andl paternal smok- ing habits-------------------------------------------- L11 'Table 2.-Effiect of carbon monoxide& exposure of pregnant rabbits on birth «-eigh't--------------------------------- 1117 T.able 3.-Compariaon of' the perinatal mortality for infants n-eighing less, than 2,500 grams, of smokers and nonsmokers- 127 Table 4:-Effect of carbon monoxide exposure of pregnant rab- bits on birth weight and neonatal' mortality---------------- 133' Table 5'.-Proportiion of: male infants delivered to smoking and' nonsmoking mothers----------------------------------- 136 Table 6.-Relative risk of congenital malformation for infants of' cigarette, smokers and nonsmokers, comparing available s~tudies with regard to study design, study populatibn,,sample size; number of infants «-irt,h~ malf'ormations, and definition of mal~formation----------------------------------------- 137 1011

Imtradiwction ('igarettesmoking isa commonhabitamong women: of'chil'd-bearin~g;i~,re in the United S'tates: Iln 1970, approximatielyone-third of Amer-ic,ul women of child-bearing age were cigarette smokers: The percent- ,z _-e of F.S. women who smoked throughout preYnancy is not definitely ;:alown, but is presumably,~ lo«-er„ probably in the neighborhood of 20, rr, •?5 percent. Witliia large fetal population at potential, but prevent- al~le, risk; t'lie relationship between cigarette smoking, and' the out- ('Olueof premlancyhas been the focus,ofconsiderableand continuing: research. Lver~.~ investigat'or who has examsnedithe relationship has confirmedl that the infants of women who smoke during pregnancy have a lower avenage birth weight than the infants of' women who do not smoke uluringpregnancy.: INIuclii evidence indi'catlesthat cigarettesmokin'g duringpregnancy causes this reductian, in infantf birth weight. Sw?v'eral investigators haved'emonstrated that tihefetal' and neonatal mortalitiy, rrate is significantly higher for the infants of' smokers than for the infants of nonsmokers; other investigators have not foundd higher mor- talityf'orsmokers' infants-Stu'dies~of the associntionbetween maternal cigarette smoking and congenital malformations have produced con-f[icting resullts,Thefollowing is a revieww of' «orkpreviiously reported and recent studies which -bear on therelat'ionshspsbet'ween ci~garettesmokingand, dilfferent outcomes~ of pregnancy. I'nadditi'on„ the chapter includes a review of the rellationship between cigarette smoking and lactatli'on. Smoking and Birth Weight Epri'demiologieal Studies LIGA'RETTE SMOKING t1ND THE LOw'-I3IRTH-WEIGHT INFANT In~ 1957, ~ Simpson (90');, using a retrospect~ive~ study~ designy, deter- mined that among 7,499 women in~ S'an Berna;rdiim County, Calif., the deliverv of infants weighing~less~than ~ 2~,5(l0 grams was~nearly t~«-ice~ as~~ 103

frequent among cigarette smokers as among,nonsmokers. Snlisequently, ~ Lowe (46) studied 2,042 women ini Birmingham, England, and, d'em- :~ onst'rated in his retrospective study that the i'nfants of smoking ~ mothers were del7vered only slightly earlier (1.4 days on the average) ~ than those of nonsmokers. He further noted that for gestations of 260! days and over, the infants of smokers «ere' consistently lighter in ~ «eiglatdnring, each«-eek of gestation~ than those of the nonsmokers. This finding' has been confirmed siilce; and figure 1 fromi the B'ritish ~ Perinatal Mortalit'y Study (13), provides illustration of this relat'ionship: Given thenearly constant disparity present betl«-eenthebirth . weights of the infants of'smokers and nonsmokers for gestations of' 260 days and over, but, absent prior to that time, and' giveni the similar birtliweight's ofi~nfant's,of' nonsn2okersands of wolnenwhogaveup smokingearly.in pregnancy and didi not begintosrnoke ag ain; ILoweinferred tliat, theidifluen:ce of' smoking upon birth weight miglitlie mainly in the later months of pregnancy. F'leemph~asized the tentative nature of this conclusion, sincetaie number ofinfants.ti-itlh a gestation of less than 260 days and the number of women whogan-e tip smoking early in the pregnancy' and' did not begin to smoke again were both small. Figure 1'.-Mean birth weight for week of gestation according to maternal smok- ing habit: control week singletons.' 125'. 2 85 75. 1 3650' 3400 2900' » (D 2650 ~ ~ 2400 12150 36 37 38 39 40' 41 42' 43+ Gestation in completed weeks ~ This term refers to singleton births In Engiand; Scotland, and wales occurring during the week of March 3-9; 1958, whichi are included in the Perinatall Mortality Survey. These comprise 97' percent of all births notified in England and Wales or registered in Scotland during this week. SOWRCEc Butler, N. R., Alberman, E. Dl (13). 704

ntly, lem- liing ige) 260 r in ters; tish this Irth ;260 ~ 1 lar lup ?we lie ion i ng ~th bk- I Lowe found that the infants whose mothers smoked throughout 1>regnancy «eibhed, on the average, 170 g~ranl~slessthan thoaewhosemothers did not smoke. In addition, he notedl thata'the ent'iredistiribu- rion of' weights of infant'sf ofl smokerswas shifted to the left (t~oward lower weights) relative to that for the infants of nonsmokers. This i6)xling, too, has been confirmed by other investigators, Figure 2 offers na)~illustration froml\TacATahon; etal. (49). Given that the infants of smokers andl nonsmokers differedi only .<li-(rhtly with respect to the duration of gestation, Lowe concluded that tiie lower birth «eight of smokers' infants must be attributed tol a iiirect retardation of fetal growth. In other words; on the basis of his ~l'ata,, the infants of smokers were sma11-for-dates rather than truly preznature. NDanyinvestigatorshavesubse,duentlly confiQ-rnedl this point (12, l4,,, 6a., 78,,83,123). Buncher (12), in a study of 40;89/ births among I-.S'. naval n ives, in the same popul6tioni studied byIlndemroodl, et al. (100), found that the imfants of smokers were,, on the average, de• llivered only 1' day earlier than those of nonsmokers. This finding accounted' for only 10: percent of the discrepancy in birth weight, be-t`veen the two groups of infants. The remainder of the studies resulted in t1xedetection of' either similar vari'ationsingestationall length or no ar.eragedsfference. In a recent study; Aiulcahyand A~furphyl Figure 2.-Percentage distribution by biith weight of infants of' mothers who did not smoke during pregnancy and of, those who smoked: 1 pack of cigarettes or more perday. I~NFANT1MEIGHT' AND: PARENTAL SMOKING, HABITS t 10 2 ~ ¢ 100, 6 il m o. 4 ~ P T ~ T r i 11 Nonsmokers ----- Smokers r". 4 5. 6 7 8~~ 9' 10 1i1 BIRTH WEIGHT (SCALE IN POUMDS; INTERVALS OF 4, OZ.). SOURCE: MacMahan, et al. (49). T 11 i 105

in a sample of 5,099 Irish mothers; concluded that although the babies born to cigarette smokers were delivered sliglitlyr earlier than those of nonsmokers, independent of age and parity, the direct effect of smoking in retardingfetal growth was more significant. The following points, based upon the results from manyy differentt studies, can be made about' the relationshi'p between cigarette smoking during pregnancy and lower infant birth weight: 1!. Women who smoke cigarettes during pregnancy have a higher proportion of low birth-weight infants than do nonsmokers. This excess of low-birth-weight infants among cigarette smokers pre- dominantly consists of infants who are smalI-for-gestational age rather than gestationally premature. 2. The ent!iredistributlion of birth, weights of' the infants of ci~ga~- rette srnoker& is~ shifted toward lower weiglits compared to the birth tivei;ghts of the infants of nonsmokers. 31 The birthi weights of' the infants of cigarette smokers are con- sistently lighter, than those of the infantis. of nonsmokers when the liirth weights of the two se.ts of infants are compared' R-i'thsnn groups of similar gestational age beyond the 36th week of gestation. The results of the studies which have beenconsidered so far identify a relationship between cigaret•te smoking, and loR-er infant birthh weight and' illustrate some aspects of' that relationship, but do not indicate whether the association is causal or indirect:The succeeding two sections ofl thi's chapter contain evaluations of the available evi- dence whi'ch bears upon tihe nature of' the association between cigar- ette smoking during pregnancy and the incidence of small4or-dates infants.. EvIDENCE FOR: A CAUSAL ASSOCIATION BETWEEN OGARETTE SDIOgING AND SMAII:L-FOR-DA'ITES INFANTS Evidence previouslyy reviewed in the 19711 and 1972 reports on the heaTthi conseqpences of smoking (101, 102) ) suggests that cigarette smoking, is causally associated withi the delivery of' slnalMor-dates infants. The following is a summaryy of this evidence : 1. The results from all 3b1studies in which the relationship between srnokingandl birth weight was examined havedemonstratedl a strong association between maternaT ci9arette smoking anddeli~-eryoflo~~-birth-weight infant~s. On t'heaverage; t'hesmoker has~nearh~-~ twice the risk of delivering a Iowbirth-«-eight infant as thatt of a nonsmoker 106

1:3, 17, 20, 25, 29, 35, 42, A 46, 47, 49, 57, 58,, 59, 65, 70, 72, 73,. ;7 . ,8: 80, 83,85, 90; 95, ,99y,1G10,113,1 18). , •?: The strong association between cigarette smoking and the de- li.\ ery of small for-dates infants first demonstrated with results from >ndtlies of retrospective design (3,13, 17, 35, 46; 47, 49, 57,68, 59, 65, ;6: 72, 73, 77, 80,85, 90„95, 99,100,118)~ has!been repeatedly confirmed >ul,,equentlybyd'atafram studies ofprospect'i!ve design (20,,25,,29, 42, ;'8. 83,113) . :;. A strong dose-response relationship has been established between c i_,r,urette smoking and the incidence of' low-birth-weight infants (25, ;.>. _~f:, 59;100,1'13). t. When a variety of known or suspected factors,ivhich, also exert an iiifluence upon birth weight have been controlled for, cigarette smok- ini-, has always been shown to be independently related to low birth ght (1,13,25,43,A13;78,83).:. The association has been demonstrated in many different coun- tries; among, different races and cultures,andl in different geographicall sott ings ('13„1~7,25, 29, 36,1f2,,13, 59; 73, 78~ 80„1 ~13) 1. G. Previous smoking, does not appear to inflluence birth weight if tliemother givesupthehabi't prior to the start of herpregnancy (25, i%y..f:9;113). ,. The infants of smokers experience an accelerat'ed, growth ratelurin,; the first 6 months after delivery, compared to infants of nciismokers. This finding is compatible with~ viewing birth as there- movaI of the smoker's infant from a toxi~cinfluence(',83). 5% Data from experimentsin animals hav~e: documented that ex- l,osuneto tobacco smoke, or someof' itsingredients results in the (lelivervof' low-birth-«eight off'spring(7, 8, 9, 23, 40, 87,117)'. Several recently published studies have provided' additional sup- porting evidence for a causal relationship between cigarette smoking, and smnll-flor-dates infants. The~ Ontario~ Perinatal' nl~ortality Study(66) was conducted among 10 teaching hospitals during 1960 andl 1961. 'The authors of this retrospective study of 50,267 births demon- strated ai significant excess of infants weighing less than 2,500 grams among cigarette smokers as compared with nonsmokers (P<0.001). Smoking was significantly dose-relatedl to the percentage of preg- nancies terminating in the delivery of a low-birth-weight infant(fig. 3). ti iswander andl Gordon (63) have recently reported data from the Collaborative Perinatal Study of the National Institute of Neuro- logical Diseases and Stroke., In this prospectiv~estudpof'3J,200~ preg- loancies„ which «°ere nearly equally divided among black and shite«-oinen, the authors found a significant dose-related exeessof low-birth-weight infants among smokers of both groups, compared to nonsmokers of'the same race. 107

Figure 3.-Percentage of pregnancies with infant weighing less than 2',500 grams, by cigarette smoking category. 12'.0 11.0 10.0 9:0 8.0 5.0 4!0 3.0 2:0 0.0 4.7 7:7 12.0 Nonsmoker <1 pack ?1 pack per day per dax. Number of infants weighing. <2,500 grams: 1,322 1,186 793 Total births: 28',358' 15,328: 6,581 (P <0.001). SOURCE: Ontario Department of Health (66). 108 '

Rantakallio (76)~ carried out a prospect'ive study of 11,005 single hirths in Finl'and. Gigarette smoking mothers hadsignifieantly moreinfants weighing less than 2;500 grams than did nonsmokers (1' <0.001).IP,'uslt and Kass (82'),, in a prospective study of' 1,040 pregnancies in E3o;~tony Massachusetts;, Domagala, et al. (19),, in ai retrospective study of 1.832' pregnanciesini Poland; and 'Mukherjee and :1lukherjee(51~), in a retrospective study of 2',886 pregnancies in India, each found a igiaificantly higher incidence of low-birth-weight infants among r i.*;irette smokers. Ilutler,et~ al. (15) have furtheranal'yzed the British Perinatal nlor- t;ulity Stud data. Analysis of the 16,994 questionnaires revealed that i? ):5 percent of the women were cigarette smokers before pregnancy. _1'fiter the fourtli, nzonth,thaspercentage had decreased to~ 27.4 per- ceiit. Given the large number of women in the study, andl the sig- iidficant changes in smokiiigbehavior«hich occurred~ Butler,, et al. f'cnmnd it possibl''e to consider the effect of a change in smoking be- havior on birth weight; bet~s~een the beginning ofl thepregnancyand the fourth month (after which smoking behavior -was reportedly ~table),. The authors stated, "If' smoking itself (rather than the type of woman «ho~ smokes) has a deleterious effect on~ the fet'us, it would be reasonable to expect the mothers who gave up smoking (1taring pregna.ncy to show differencesin: tlhebirthweight and peri- iiatal mortality of theiroffspri~ng compared with thosewho~contii2ued to smoke."' Their results are presented in figure 4. The birth~ weights hy smoking categorieswereestimat~ed byusingamain: effect model Withoutmediating ~~-ariabl'es. However, the authors reported that whenn the mediating variables (soeial' class, maternal age;, parity,, maternal lieight;, sex of infant, gestatiionalage, and perinatall mortality): were~ alloNvedl for,, theresultis: of' theanalysis were very.similar. The effect of cigarette sinoking, before pregnancy was insignificant compared to that of smoking regularly after the fourth~ month of gestationL Ti heauthors concluded, "The~ finding that a change~ in maternali smoking liabit~schlring, pregnancy had the effect of putting the baby intoabiu•th weight and perinatal mortality categoryassocia,ted withthe newsnlokiiig: habits points toward some kind of cause-effect,relationship. *~*'ll'hisfinding,is further strengthened by the birth .ti-eigl,itanaly.sis which shows that the diminution in birth weight of the offspring of sm:okingnaotherspersists and is indeed little changed .vlienallowance, has been made for a number of other social and obstetric mediating, factors."' 109

Figure 4-Average birth weight by maternal smoking habit, (a) before current' pregnancy and (b) dluing, current pregnancy. Number of cigarettesJda 3,400 9" E ~ 3;300. 3,100- 0 I~ . ,k,._. I I I I --L----- --., 0 20-30 1!Q-19 5-9 0 1-45-9, 10r-11920-30, tVumberof cigarettes/day before current pregnancy SOURCEc Adapted f'rom Butler;,et aii (15):. lbtal births: 21,671 . EVIDENCE FOR'AX YrTDIRECT ASSOCIA1Zo1'BETZ4'IIEN LIG.IR;E=S3IOIiI\G AND SMALL-FOR-DATES INFANTS Yerushalmy(113,114, ;110.)~ has suggested, that smoking isan indexto a particular type of rehroductive outcome and thus does not pl'ay a causal role in the productian of small~f'or-da,tes infants. He has de- veloped several, lines of support for this~ hypothesis, from an analy,sis, . of data from t!1ie prospective investigation of 13,083 mothers in the Oakland Child H'ealth and Development Study. H'e has emphasizedl that ineffecti've randomization and the phenomenon o' self-select!ion complicatetlied'eveloprnent of' appropriate inferenceswith~ regard to, causality-.Such difficulties d'o~ notpreve,ntthe identification of causal associations, but t1leydemand careful and criticall anal'ysis~ of the data. Yerushalmyhasquesti~aned the causal nature of the relaftian- shipbetween cig2rettestnokingand small-for-datesinfa,nts because of: (a)~ Therelationship~ betweenthesrnoking h.zbitof the father and low birth weight oftlie infant,, (b), behavioral d~iffererucesbetween smokersand' nonsmokers; and (c) comparison of' theNrth weihhts 110 in current' pregnancy; after the fourth month of gestation I

i current tes/da la ncyr; lanth i ~ I 'ptal jths: 67T ~ of a«oman's infants born during the periods when she smoked ciga- rettesand when she, did not. 1 eruslialiiny (114) has stated that the smoking habit of the father (,ou lil! not reasonably be related to the birth weight of the infant. From~ prel'iminarydata derivedl from t'hestudy, however,, hedetermined' t!iat there wasaiL increase& incidence: of' lo«-birt~h-weightinfants wlien thefathers~ smoked and, moreover, thereR-asan apparent,dbse- rnsponse relationship as found for maternall smoking. However, he noted that'onlywhen, both the husband and the~ wife smoked wa& the inridence: of low-birth-weigl'it babies increased. He felt that theselindings supported the conclusion that smoking was a marker of t~~pes of individuals and not a causal factor for low birth weight. t~)therinvestigatars have since examineds thisrelationship: (',49,, 100), hilt none hasconfi,rmed an independent association forpaternal;nloking. Theassociatiion between paternal srnokingand birth«eight :il)pears to be an indirect one. Paternal and maternal' smoking, be- li:ivior are higlilycorrelated and maternal smoking is strongly related to infant birth weig)1t: Underwood, et al. (100)~ studied 48,505: worn.en,t heir h2zsband's'smokingbehavior;and the relation with birth «.eight. (table 1). If the mother was a nonsmoker,, then the father's smoking liadl no influence on the birth weight of'the infant. 'I':L~B uF L.-I'nfant birth ~ weight ~~ by ~ maternal, and paternal~ smoking habits ~ Mothers: Fathers (nonsmoking mothers) Cigarettes per day Birthweight (grams) Birthweight, (grams) Number - Irlumber, Mean IDiHerenceI Mean DiSerenceI . lex ~ aa de- rsis t}le ;ed on ,rd of of h- se er !n tls \o ne------------------ , 24„86+i' 3, 395 0 9, 547 3, 396 0 1 to 10----,-,------------ 7,,609' 3, 2W 109 3,493 ' 3,389 7; 11 to~30---------------- 14„450 3, 19& 199 10,403 ' 3; 3911 5 >30---__-,---,-_-------- 1,570 3,182 ' 213' 1,330 3,393 3 I Nansmoker mihus smoker. Sdurce: Underwood, et al. (t0ll)1 Yerushalmy (115); pointed out that other investigators had found marked d~ifferencesbet'weensmokersand nonsmokers. In his own Audhr; hefound that nonsmokers used contraceptives sie ifiicantl'ymorefrcquently, than did smokers.BZloreover,ai significantlyhigherprrnhor.tion of smokers drank coffee; beer, and .Fhiskey.I3o«-ever,~ herlid not adj2ist for these variables in his, analysis of theassociation, between cigrtiret'tesmokingand lower infant birth weight. O'tlheri'n- vestigators have also found di'fferences between sanokers and non- smokers. Forexarnple; Frazier„et.al. (w5)found significant d~ifferenees in the distribution of parity, work history;, education, and psy¢ho= 11n

somatic complaint score between smokers and nonsmokers. However, «'hen smokers were compared with nonsmokers of' the same parity;, education,workhistory., and psy.chosomatic coniplaintscore, cigarette smokers still had ai significantly high~erproportioni of small infants than did nonsmokers. Asprevi~ouslymentioned, whenever otherflaetors known or suspected to influence birth weight havebeeai controlled, cigarette smoking, has always been dernonstratedl to have an inde- pendent and significant elfect: Ounsted (69)~ offered evidence that tlre~best~predictor~of'the~ birth, weight of a mother's. future offspring, was the birth weight of her previous children. Herriott, et al. (,35~)~ found~, prematurity rates for previous pre;nancies~ among smokers t'o~~ be~ markedly higher thann among: nonsmokers, independent of~ parity, height, and social elass:~ Ev~i'dentlx~ awomam whose~ previous! . infant!s~ have been small tends~ to continue~ to ha~ve~relativel''y~ smaller than a~verage~ infants in subsequent pregnancies: The question is, wil'1~ tliose~infants~~ be enen~ smaller than, expected if she smokes? Goklstein,~ et ~a~11 (2S) ~, in a~ comprehensive review, proposed a~~ research design i'n whichi a woman would serve as her own control to compare outcomes of pregnancies during which she smoked with those diiring, which she did not with consi~deration of~the~ eff'ect~ of' parit'y~~ on the~~ outcome. Yerushalirsy (1'12)' has~ recently tested this type of research design, usi'ng~d'ata fcom h~is~O~akland Gro~wth~Study: ~Pith~information on the~ age at which! awom~an began to~ smoke cigarettes„ her sm:oking~~ status~ d~u~ring, th~e~ pregnancy actually studied,, her~ prior~ reproductive experience, andi the outcome of' her present pregnancy, the author compared the outcomes of' pre,-nnncy during periods of smoking and nonsmoking using the woman as her own control'. As the author noted, "If smoking causes the increase in low-birth-weight infants, then the incidence of low birth we.ight for infant's born to smoking, mothers dizring the period before they acqu2red the smoking habit, should be relatively low. If, on the other hand, the high, incidence of' low birthh weight is due to the smoker; then it should!be high for infants of fut.uree smokers also when they were born before their, mothers started to smoke." Yerushalmy theni proceeded to compare the reproductive experiences of' four groups~ of women:(a)l Those who smoked in none of their preb ancies,, (ib), those who smoked in alli of their pregnancies~,, (c) thosewh:oweresmoking now but prez:iously bad not smoked dilring, some pregnancies (future smokers),and(id)thosewhowereex-smokers now but had previously smoked during some pregnancies.. These outcomes are shown in figure 5'. The incidence of low-bi'rtfi- weight infants, in the pregnancies of thefuture smokers, before theystartecl to smoke,, wassimilar tolha.tfor women~ who smoked in everypregnanc-y, which was~ significantly- higlierthan that ofinfantlsfrom. 1112

iwever, ~arity, rarette hfants actors ;o11ed;inrle- birth. 4 her ds for tbann class. ds to luent than arch pare ;ring 1 the. ~rch 6on King, tive thor and tedye the lers i be Irthb ure I to ces eir Fc), ng ~s'.. 11- 'y ~p. rn luothers «-ho had never smoked. He also noted that ex-smokers, during tfw period before they quit, gave birth to relatively few low-birth- v,~, . larl a iirfants ; the incidence~ was si~gnificantly~ lbwer than for mothers' Wim s~inoked during~ all of their p~regnancies. He~ concluded that the~ tinriin~rs cannot be~easily~ reconciled .vith~ a cause-effect basi~s~fbr~smok- ~a ~1,: ~,irid birth weight. ItIe~ said, "Rather the ev~i'dlence~ a'ppears,to ~ support ti iee hypothesis that the higher incidence ofl lotiv~-birt~hrweight~ infants is &w to~t~he snaok~er;~ nott the s~ntokin.g~"~~ -1'liere are several considerations' which limit the interpretations v.loiclr can be drawn from this study. The information on smoking LwIS,Ivi~or~ of' the women during, past pregnanci~es~ was~ apparently ~ dle- ri % cd from the woman's age when she began to smoke, her smoking, ',It-?tavior~~early~ in the~ studw~ pregnancy„and the~age~at which she had prior pregnanci'es. Thus, if~ the woman reported that she, began _1n0king at a certain age, an&that she was still smoking at the time of ; iw stud}-, it « as apparently inferred that she had smoked during all of h(,rprebziancies. Since~noquestibns~were~~spe~cifiically~asked~abou~tactua~l >+nokiug behavior d~urin,g~~ each previ~ous~ pregnancy, it is possible that t:w woman indeed had not smoked during~every~ pregnancy~ or that tl eamoudit or way she smoked had differed from current smoking Figure 51-Percent of low birth weight white infants by smoking status of' their mothers. Gravidas' smoking habits Percent low birthiweight infants in previous pregnancies Nonsmoker (during all pregnancies) Nonsmoker (future smoker)' Smoker (during all pregnancies) Smoker (future ex-smoker) 5.3' 1 2,529 9.5 I'- 210 8.9 *$ 2;(176~~ 6.0' 1 ~ 651 4 6 8 10 Percent. 'Difference is statistically significant (P <0.01). °°Difference is statistically significant (P <0'.02)'. SOURCE: Adapted from YerushalMy, J. (112). 113

habits. This would be important t'oknow given thest'rongdose- response relationship which has been established between cigarette sm:okingandlowbirtTr weight, and would tend tomakethereproduc- tive outcomes for ea-smokers similar to those of' nonsmokers; and different from those of' women who smoked in all' pregnancies.. For ex-smokers, the age at which, smoking began was not elicited. Hence, some of the infants of' es -smokers may have been born before theirmothersacquiredr t'he~ smoking habit. Thi's.vould alsot'end to make the reproductive experiences of es-smokers~ more like those of nonsmokers and dif£erent from those of women who smoked in all pregnancies. No direct adjustm:ent for age, parit!y.,, and other variables was reported~ although Yerushalmy stated that the stud'y population was limited to the births that occurred to women at age 25' years or less: He notedi that, "In order to adjust for parity, the same comparisons were performed for firstborn infants only. The numbers were reduced considerably, but the same tendencies as foundi above were noted."' However, no data were presented. Primiparous births and births in teenagers are stronglyy associated with: the delivery of low-birth, weight infants.. If the pregnancies which occurred among future smokers included a: predominance of very: young women and priini'parousbirths, the reproductive experiences of future smokers wouldl tend to be similar to those of women who smoked during all pregnancies, andl different from those of nonsmokers.. In the absence of more precise i'nformationi on actual smoking behavior during pregnancy and more rigorous adjustment for maternal age, this study does not provide acriticall test of'thehypothesis that it is the sm:oking, d'uring pregnancy which is responsible for the higli, proportion of small-for-dtLtes in- fants born to women who smoke. Expeximental Stucliea .,~TL7DIES I.x A~NI3PALS Tobacco Smoke Several investigators 1avediemonstlrat'ed that eaposure, of' pregnant. rats or rabbits to tobacco smoke lead5 to: a reduction of birth «-eig ht in the offspring, as comparedto controls (23,,8i, 117):. Younoszai, et al. (117) reported data fronm studies in, rats which indicated that some agent present in cigarette smoke other than nicotine was responsible for thereductiion in birth.veight observed. The aut~hors,suggest~ed that carbon monoxide might also not be responsible for the retardation of

I d'ose- kre.tte bduc- and i ~ited. efore id to. Be of' ti~ all liwas was less. sons ~ aced ;ed." ~ is inil ight ~ kers ~ous ~ d to ~. and' ; 6se ~, tore ~ ~ide. ~. ncy a nt' ;ht al. me ble: iat of fetall growth; however, the evidence~ presented was inadequate to support a firm, conclusion. Haworth and Ford (33) recently extended the experiments of Younoszai. A group of pregnant rats was exposed t'~o, cigarette tobaccosmoke for 6 to 8 miirutes; five times, a day, from, days 3 to 20' of ges- tation. These rats were compared with another group whose food intake was, restricted to the~ amount actually consumed bythe~tobacco~exposedrats, andl both, were compared to a welMed control group. The animals in both experiments were killed on the 21st day of' restation,, and weights of the entire body~„ theliver;and the kidney of each fetus were recorded' The total average fetal weightof the ;rroup exposed tJo, tobaccosmok~ewassi'gnifiicantlylowertlian that of both the food-restricted aud' control groups. Thef'etall weigTitsof the latter hwo~groups werequitesimil'ar: Protein and DNA analyseswere performed separately on the entire forebrains and hindbrains of the fetuses and on the entire carcass. I3othDNA and protein were sig- nificantly and proportionatelyy reduced in, the carcass and hi2idbrains of the animals exposed to tobacco smoke. This implies that cell number was reduced and cell size was normal, and suggestst'hat the exposure~ to tobaceo: smoke either inhibi'ted cellular proliferation or acceleratedl celluhar destruction. Nicotine Several workers have: demonstrated that chronic injections of large closesofnicotineinto pregnant rats resulted' in a reduction of' birth Wei!ght of the offspring(7;8,,9, 23, 40). Otherinvest'i:gatorshave, de- termined that trit'ium-labeIled nicotine injected into pregnant rabbits and' C1{-l'abelled nicotine injected into pregnant mice crossed the placenta~ tlo; thed'eveloping; embryo and fetus (89, 98)1. Kirschbaum; et al. (44 found no significant acute effects of small doses of nicotine, injectedl intravenously into near-term sheep, on blood gas composition, pH, blood pressure, or heart rate in either the: ewes or their fetuses. The authors concluded that the influence of' maternal smoking upon the fetus must result from chronic effects or through the effects of other variables which they did not study. Recently,, Suzuki, et al. (94) ~ evaluated the short-term effects of' in- jected nicotine on thecardiovascular performance, acid~basestatus, and oxygenation of pregnant female Rhesus monkey-s and their infants during, the second half of gestation using the mothers as thei'r own controls. Nicot'inew.as administered either asasingleintrav.enous: dose of 0.5 to 1.0 n1g. or as a continuous infusion of 100 µg./kg. over -105-028 0-73-0 1is

a 20-minute period. The' injection of nicot.ine in the larger, single dose into the mother produced a ri'se in maternal bIood'. pressure and aa falll in maternal heart rate, and an immediate fall in both fetal blbod pressure and fetal heart rate followed by persistent hypotension and tachycardi~al in the fetlus.Subsequent to theinj'ection of1!.0 mg./k~g. ofl nicotine into pregnant monkeys,, in~ a single dose, significant changes in the arterial blood of the older fetuses incllud'ed a fall in pH, a rise in base deficit, and afal'1 in oxygen tension. Carbon dfiox~idetensione remaanedunchanged.Nicotine inj ected directlyy int'othe fetus prompted an immediate rise ini fetal blood pressure and a faIl in fetal heart rate. These responses were similar to those previously seen in the motliers following a direct injection of' nicotine.. The changes were more prominent in older rather than in, younger fetu~ses.'TPhe authors sum- marized their findings by stating that: (a) fetuses in different ges- tational stages are~ differentially responsive to a given dbse of nico- tine, probably because of the different sta'gesof devel'opment of' the autonomic nervous system; (b) diminished intervillous space per- fusion resulting from vasoconstriction intlheuteri~necirculation ap-pears to be mainly responsible for the fetal asphyxia following the injection into the mother, because: fetal hypotension and bradycardia were not preceded by thet''ransient hypertension seen f'o1lowingthe direct administration of' nicotineto:thef'etus~;, (ie)the differences be-tween the results obtained' by Kirschbaumi and by Suzuki~ et A may reflect either the! considerabledosaged'ifferenees or species, differences; and (d) the doses which the authors employed were much larger than those which a human mother would absorb from usual cigarette smok- ing, but that differences ini tolerance t'o nicotine between the~ Rhesus monkey and'i humans would imply that the dosages were, in fact,, com- parable and that, "Hence, it cani be envisaged that the concentrationn of' nicotine which could be reached in the organism of a smoking mother would reduce oxygen availability: to the fetus." Carbon Monoxide Longo ('Jy5) has reviewed the work of several investigators which has demonstrated the transplacental' passage of' carbon, monoxide from mother to fetus in animals. A recent study which related CO, to birtlh weight was published by Astrup(2),. He found that continuous ex-posure throughout gestation of' pregpant rabbits' to different levels of'ambient , carbon monoxide resulted ini a stlatistically sirnificant dose-related' redkiction in bi~rth-weight (table 2). Theactua1 significance level was not reportedL 1116

TaBiE2'.-Effect of' carbon monoxide exposure of pregnant rabbits onb~irthu.eigTit f3roup 1, CkrouR2, Group 3, 0 percent 8 to 10 percent 16Ra 1B'percent COEItl CDnUCOlitx~ Number of' pregnant,rabbits---------- _- 17 14 17 T6tal, number of babies--------------- 116 81 123 Average weight ofi babies in grams----- 53. 7 51. 0 44. 7 JOti.ucE: Astrup, P: (E). Polycyclic' Hydrocarbona' Polycyclic aromatic hydrocarbons (P:,-~H) suchiasbenzo(a)pyrene(B'_1P)'~ are constituents of' cigarette smoke whicii, have been impli- cated in thegeneration of cancers in many animal species (111). N''o, st'udies! presently available relate benzo(a)pyrene to a reduction inn birth weight of exposed offspring. Evidence suggests, however, that BAP does reach and cross the placenta. Aryl hydrocarbon hy&oxy.lase (AHH)~ is a part of thecytlochrorneP`-45'Q:-contains'ng, microsomal enzyme system,, present in many t'issues of different species: This enzyme sy stem isindueed to hydroxylate polycyclic aromatic hydro- carbons after exposure of' cells to PAH. Several' investi'gators~ have utilized the inducibility of the enzyme system to demonstrate indirectly that benzo(a)pyreneand oth~erpolycyclic hydrocarbons reachths~ placenta and fetus. Welch, et al. (108) extended this work by administering the polly- cy-.clic liydh•ocarbon,3-metliy]chola'ntlirene(3-MC), to rats during late gestation. The metabolism of'benzo(a)pyrene'«as studied in vivo' (us- ing' trit,iumrlabelled benzo (a) pyrene) and in v itro,AHHI activity was increased in fetal livers to adult leveli; by pretreatment with 3-MC Since a relatiivelyhigh dose of poly cy.clic! hydrocarbon was: requiredd to stimulate enzyme activity in the fletus; compared to the dose which stimulated placental enzyme activity, theauthors, suggested that theplacentlai may protect the fat'us, from exposure to polycyclic hydro- carbons. However, immaturity of the fetal enzymesystlem might also account: for its apparent relat'iveinsensitivi'tyto polycyclic~ hydro- carbons. Therefore, an exposure of' the fetus to 1evels of pol'y- cycliehydrocarbon similar to those experienced by themot''her cannot be ruled out by the available data. 117 O ~'. ~ ,Dr O

Schlede and Merker (86), have studied the effect of benzo (a ) pyrene administration on aryl hydrocarbon hyd~roxylase activity in the mater- nal liv.er;, placentlay andl fetus oft1lerat during the latter half of gestation. The pregnant animals were treated with large oral doses of benzo (a) pyrene 24 hours prior to saerifice. Control rats had no detectable levels~ of' aryl hydrocarbon hydroxylase in their placentas. Treatment `vith benzo(a)pyrene resulted in barely detectable placentall lovelson gestation day 13, but steadily rising values~untlil d~ay1i5; andl then constant levels thereaf tier. N'oactivity was detectedlinthef'etusesof untireated controls. In the treated animals, the fetal enzyme activity rosest'eadilyfromthe 13thtotlhe18t17 day ofgestiation.Theauthorsf concluded that the stiinulaatory effect of benzo(a)pyrene treatment on aryl hydrocarbon hydroxylase activity in the fetus demonstrates thatt benzo(a)pyrene readily crosses the rat placenta. ST'L; DIEB' Ii1 HII3I:4\ S Carbon Monoxide Smokers~ andl their ~~new~born~ infants~ have~ siignificantly ~elevatedl llevels of' carbon, monoxide as compared with nonsmokers and' theiir infants (31, 84, 88;116). Recently,,I3aribaud',,et al. (5) studied 50 nonsmokers and' 27 c.igarette smokers and their neav.borns. Alli smokers inhaled. The authors foundlthat the~mean level of'C4 contentt in the~blood of non- smokers was 0'.2i1 volumes percent compared with 0.672 volumes per- cent in th:e~ blood of smokers~.. The vadues~ for, bl'ood sampl~es~ from the~ umbilacal cords~~ of~ their newborns~~ were 0!352 ' and 0.949 volumes~per- cent; respectively. AToreov.er, a definite: dose relationship was foundi betw~eeni CQ~~ levels~~ and number of ciga;rettes 'snioked. ~.'ounoszai,~ et al. (116) found,~ in ad~d~~i'tion to~elev.ated carboxyhemo- globin levels~ among~ the infant's, of smoking mothe~rs; significant elevation of' mean capillary hemotocrit's, and significant reduction of~ stan d4rdl bicarbonate levels,, as~ compare'to the~ infant's ~ of nonsmoking mothers.. Since no evidence for nicotine effects upon blood' glucose, seru,m~ FFA levels, or urinary catecholamines, or for hypoxia was~~ present„they concluded that the higher hematocrit levels in the infants of~ smoking mothers may~ have~ represented~~ al compensatory response~ to the decreased oxygen-carrying capacityy of' tlie blood due to the presence of'carlaoxyhemoglobin. Longo (45) pointed out that a level'ofl 9 percent carboxy~hemo„ l~obin in thefetus~ i~:s1he eqpivalent of~ a 41 percent~ decrease in fetal blood flow ~~ or~ fetal hemoglobin concentration. In revie.ving, tl)e~ studies of~ CQ~~ l'evels,in human mothers and theia•~new~borns, lse~ made~ the follow~-~ lie!

I ~'rene at~er- f of loses I noo itias. ,ntal and lzses wity hors t on that r Vels i lnts kers rhe ;on- >e r- the 5er- 4nd i lno- ant, ~ of i'ng bse, Lvas, ,nts Inse the ing comments: "These~ samples were obtained at the~ time of'vaginal. deh~-ery~or Cesareansection and may~not~accurately reflect the~ normal <<<il!ues of (~CrOHb)F~ for~ several reasons. The~~ number~ of cigarette.s~~ ~roioked by ~ the~ mothers dnring labor~ may~ be~~ lEss~ than their normal roidsumption an& was not~ specified in these~ studies. The~ blbod san7, p1cs~: were collected at varying time periods f?allowing~ the~ cessation of'sinok~ing~. In addition, many~ ofl the~~ samples were probably~ taken~ c;irly ~in the day before CG1Hb levels had built ulp to the~l~evels~~reaclTed ,ifter~prolbnged~ periods ofl smoking~. Thus actual l~evel~s~~of' (CQ'Hb),:;,~ and (~C~QHb~)~ F may be~hig)zer than the reported~ values."~~ Pblycy.clic Hydrocarbons The~ results of several studies~ concur~~ that'~ cigarette~ smok~ing, is~~ Arongly, associated with the induction of aryl' hydrocarbon hydrox- vlase~in the~hnma~~n placenta (18;,38; 61'~,~99,~ 1~09)i. This~ findingiQnplies that'~ benzo(a)ipyrene or other pol~rcyclic hydrocarbons, reac,h the placenta. To date, evidt;nce to support the passage ofl polycyclic hydro- ca~rbons~ through the~ placentai to the~~ human fetus has not'~ been published. Vitamin B. and Cyani'de Detoxification. -.NTcG'arry and Andi•ews (.l:8) determined serum vitamin Blp levels in 836women at their first, prenatal clinic visit. They found that the serumlel-elsfor smokers were signific<antly lower than for nonsmokers. After adjustment for gest'ationad age, parity, social class, hemoglobin llevel, hypertension, and maternal «~-eight,sm~okers, still had signifi- cantly lower levels of Bl,. They also foundl a direct, statistically sig- nifa'cant dose-response relationship between cigarettes smoked and serum vit:arni'n B12, level. They again confirmed the relationship be- tween smoking and low birth weight!. The authors suggested that the lowered vitamin~ B,z levels reflect a disorder of cyanidedetoxificati~on.. Cyanide is a~ demonstrable ingredient in cigarette smoke (39, 60, 62,, 6'~.'; 68. 74, 94. Vitamin G Venulet (1Q5;1~06yZ07)has~ demonstrated that the vitamin C' level is significantly lbwer in the serum ofl women who smoke cigarettes during pregnancy, comparedl to values for their nonsmoking counter- parts. Possible Mechan:isms. The following mechanisms, have been proposed for the production of' lo«• birth weight and other unfav.oralilie outcomes of pregnancy following exposure toci~ga:rettesmoke: 1119

11. Adirecttoxi~cinfiuenceof'constituentis,ofcigarettesmokeupon, the fetus (2; 45, 50; 51, 117). 2. Decreased placental'perfusion (94)... 3'. Decreased maternal appetite and diminished maternal weight gain, with secondary effects upon the fetus (B, 33,, 36,, 65, 75, 99- 117). 4. A direct effect upon the placenta (36, 57, 65, 110). 5. An osytocic effect on uterine activity (44). 6. A disturbance of vit'amin B'lp metabolism (48). 7. A disturbance of'vitamin C metabolism (105,106,107)~. Of the potential mechanisms, available evidence suggestls~ that neither decreased maternal appetiteand, decreased maternall weight gain nor a, direct effect upon the placenta are responsible for a sig- nificant reditction in, birth weight. Dxisting, evidence does not permit firm conclusions ~ concerning the relative significance of the remaining mechanisms. Timing of 'th-e Influenee of'Cig°arette Smoking on Birth Weiglzt Several investigators have published resullts which bear on the time. period during which exposure to cigarette smoke: most affects fetal growth. Low,e! (/'6)~ and Zabriskie(;118) have offered evidence whiehsuggests that cigarette smoking intiuences fetal growth most during thesecond!halfofpregnancy.Butl'er, et'al.(15)~ found thatthebirtlht weights. of infants of women who did not smoke after the fourth month of pregnancy were essentially the same as those of'the infants of' nonsmokers: Ti his implies that the influence is most probably exerted after the fourth montifl: of' pregnancy. Hlerriott, et al. (35), however,, found that women in lower socioeconomic classes who gave up smoking early in pregnancyt'~endedto have intermediate weight babies as com~-pared with nonsmokers and persistent smokers, but his numbers of' women were smallandtheresul't'swerenotst'atistica~llysi;gnQficant: Underwood, et al. ('100)found thatcigaret-tesrnokingin anysi'ngle trimester was associated with: a lower birth weight of the infant, although tliedifferencebetween th~ebirth~ wei~ghts, of infantsofs women who smoked only during a single: trirnester and infants of non- smokers was not statistically significant because of small numbers. Several investigatorshaved'etecteds a nearly constantdi'6ferencebe-tween the birth weights of the infants of smokers and nonsmkers; delivered dilring, the last month of pregnancy, following gestations ofl comparable length [fig. 1, (1~1)].Although this observation: is 17a.

eight y, 1 99= i compatible with the suggestion that the influence of cigarette smoking uponithe, fetus occurs prior to the last montli, of pregnancy, it is based upon data derived from cross-sectional rather than longitudinall studies. 'IL'heresult'sofm:anyhuman epidemiological studies~ suggest that maternal smoking prior to pregnancy does not influence fetal weight gain (15, 25,46,49;113). Site: of' Action at the Z'issue and' Celliud~ar Level rhat ight ~sig- tmit ling I I I I ; ;.~~. a W ch 6g th th. of ~d r, ~g n- bf r Tlie use of labelled nicotine (98) and the preparations of autoradio- grams have permitted the localization of nicot'inewitihinthe~ tissues of the fetus and mother. Tjalve,,et al. (98) found' high lievels of nico- tine in the respiratory tract, adrenal, kidney, and intestine of 16- to 18'- aiiy miee fetluses. The use of other labelled constituents during various parts of gestation might further the und'erstanding of how certain ingredients in cigarette smoke produce an impact upon birth weight. Ilatirorthand: Ford (33) havereported data which su~ggest that the reduction: of birth weight of rat fetuses caused by the action of the ingredient(s) of tobacco smoke results from~a reduction ini cell number, but not in cell size: Signiicance o ftlie Association Among all women, in the L nited States„ cigarette smokers are nearly twice as likely to deliver low-birth-weight infants as are non- smokers. Assuming that 20 percent of pregnant women in the United S'tates smoked cigarettes through the entire pregnancy (extrapolated from data on changes in smoking behavior during pregnancy collectiedd for the British Perinatal Mortality Study), taking, into account the apparently different risks of' delivering: ai small ~ for-dates inf'ant for Caucasian and non-Caucasian women: who smoke during, pregnancy; and considering the number of infants with a birth weight less than 2,500 grams born to Caucasian and non-CRucasian, «•omen,, an excess of '~ nearly 43,000 occurred in the 286,000, low-birth-wei'ght'infants among the3i500;000inflants born in the United Sta.tesin 1968, becausee of the increased risk among women who smoke of having small-for- dates infant's.Since neonatal mortality i~s~~ higherforlo-w-birth-weigth infants, n-ithgestationaI age held constant, the excess of small-for-dates infantsanaong, smoking mothers would imply a significant excess morta~lityy risk as we11. 121

Birth Weight Sunmm,a ry A causal association between cigarette smoking and fetal growth retardation is supportedl by the following evidence: 1. The results of all 42' studies in which the relationship between smoking and birth weight was exazn.ined have demonstrated a strong association: between cigarette smoking, and delivery of small4or-dia;tes infants. On the average, the smoker has nearlyy twice the risk of'delivering a low-birth-weight infant as that of' a nonsmoker. 2. This association has beeni confi'rmed~ by both retrospective andd prospective study designs. 3. A strong dose-response relationship has been established betw een cigarette smoking and, the incidence of' low-birth-weight infants. Available evidence suggests that the effect of smoking upon fetal growth reflects'. the number of cigarettes smoked daily during a pregnancy, and~ not the cumulative effect of' cigarette smoking whichi occurred before the pregnancy~~ began. 4.When a, . variety of known or suspected factors which also exert'an, influence upon birth weight have been controlded for, cigarette smoking has consistently been shown to be independently relatedl to low birth weight. 5. The association has been found in many different countries, among different populations, and in a variety of' geographicall settings. 6. New evidence suggests that if a woman gives up smoking by theh fourth month of pregnancy, her risk of delivering a low-birth- weight infant is similar to that of'a nonsmoker., 7. The infants of smokers experience a transient acceleration of growth~ rate d'uring the first 6 months after delivery, compared to infants of nonsmokers. This finding is compatible with viewing birth as the removal of the smoker's infant from a toxic infl'uenee. 8. The results of experiments in animals have shown that exposure to tobacco smoke or some of its ingredients results in the delivery of low-birth-weight offspring. New evidence demonstrates that chronic exposure of'rabbits.to carbon monoxide during gestation results in a dose-relatled reduction in the birth weight of their offspring. 9. Data from studies in, humans have demonst'rat'ed that smokers' fetuses are exposed directly to agents within tobacco smoke; such as carbon, monoxide, at levels comparable to those which have been shown to produce low-birth, weight offspring in animals: 122

Cigarette: Snnokiarg, and Fetal and Infant Mortality In,troduction Several previous studies of' the relationship between eig,arette smok- i71g and higher fetall and infant mortality among the.infantls of smokers have been reviewed in the 19711 and 1972 reports on, the health con- sequences of'smoking, (10 ; 102). In many of these studies; the authors combi'ned two or more cat:egoriesoffetal andl infant mortality., Differ- ent mortality outcomes,, such as spontaneous abortion, stillbirth, andd ileonatal death,, areinfl.uenced bydiffErent: sets of factors. Among other factors,, the frequency of' abortion is influenced by congenital infectipns,hormonal deficiencies,,and cervicall incompetency. In addi-tion to other factors, the frequency of stillbirth is infl'uenced by pre- matureseparation~ of~ t'heplacenta,, ut'erineinerti'a,,and dystocia. Along with other factors, the frequency of neonatal death is influenced by ,-estational maturity, birth injuries,, and delivery room and nursery care. Separate an:alysis ofl the relationship of cigarette smoking to each different mortality outcome; with control of the unique set of factors which influences~ it, mayfacilitatle~ understanding, of the rel'ationship.. Sp:ontaneous Aborti,an;. Previous epidemiologicall and experimental studies of the relation- ship between spontaneous abortion and cigarette smoking reviewedl in the 1971 and 1972 reports on the health: consequences of'smoking (101,. 102) fornrithe basis of the following;statements: The results of several studiesY both: retrospective and prospective, have demonstrated ai statistically significant association between ma- temlal' cigarette smokin; and spontaneous abortion (43, 65, 70, 99, 118). Data from some of these studies have documented a strong, dose- response relationship between the: number of cigarettes smoked and the incidence of spontaneous abortions (70, 99, 118).. In general, vari- ables other than cigarette smoking (!e.g., maternal age, parity,; health„ desire for the pregnancy,, and use of'medicat'ion), which may influence the incidenee of spontaneous abortions, have not been controlled. Tihe results of the one study, in which adjustment for the woman'ss desiree for the pregnancy was performed, indicated that after such adjjust- irnent cigarette smoking during the pregnancy retained an associ'ation with spontaneous abortion ofborderli~nesignificance (43). The time period during whsch~ cigarett',esmok~ing might'exertan influence on the incidence of spontaneous abortions has not been determined. Abor= 1 23'

tions have~ been prod!u~cedl in animals only witlilarge d~oses~ of nicoti'ne~ (w3; 96;,104); tlie, releva~nce~ of~ these ~~ stu~dies ! for huQnans~~ is uncertain. SPO\iTASEOOL•S ABORTIO1i'i SLM3L!:1RY Although several investigators have found a significantlyhigher, dose-related incidence of' spontaneous abortion~ amongcigarett'esnokers as compared to nonsmokers,, the Iack of control of'significant variables other than cigarette smoking does not permit a firm con- clusion to be drawn about the nature of the relationship. AStiZlb'irtJi Epidemiological: , studies of the~ association~ between czgarette smok- ing and stillbirth previouslW reviewed in the 1971 and! 1972 reports,on~ the lieal'th~ consequences of smoking (101, 102) form~ the basis for thee following stat'ements:. In one group of' retrospective and' prospective studies, a higher still~ birth rate was fonndl for the infants of smokers as compared to thosee of nansxiokers (14; 25, 43)'., In another group: of retrospective and prospective studies, no significant difference was detected in the still birth rate among the infants of'smokers and nonsmokers (16, ,20; 85,,99, 100) . Differences in study size, numbers of cigarettes smoked, or the presence or absence of' controli of variabl'es,suchas age and parity, which may influence stillbirth rates, were probably not sufficient to explain the differences in results olitained'. Several recent epid'emiological studies have added t'o our under- stand'ingof the: relationship between cigarette smoking, and stillbirthL Niswander and Gordon(63) have reported data from 39;2115 ' preg- nanciesfolllowed prospectively and collectedl between 196Jandl 196'Bat 12 university hospitals, in theUnitedl S'ta.tes.A random sample of women who presented to hospital prenatal clinics were:enrolled in the study. The authors reported no increase in stillbirths among whi~te smokers as compared with white nonsmokers.11: higher incidence of' sti'llbirths! was, foundl among, black women who smoked than among nonsmoking black women, and a dose-response relationship with eigarettessmoked was suggested, although thefind'ings did not attain statistical significance: Tkeresults~were~e not adjusted for other vari- ables. FR'ush and Kass, (82) flound, in a prospective study of 3,296 pregnancies at Boston CityHospital,, anonsignificantincreasein 1ziS

~-.ti1lbirthsamong white women who smoked, but a: statistically sig,-txifi- rant increase in stillbirths among,black women who smoked (P<0:02). 'f 1'iese findings are consistent wit1l, those previously outlined by Ir'r~irier,etl al. (25) and Underwood, et al., (99),., R.umeau-RRoquette (81), in a prospective study of 4,824 pregnancies n Paris, demonstratedd that the risk of stillbirth, was significantly Isi'grher for cigarette smokers than for nonsmokers (P<0.001). The :u,rthors, also presented evidencet'hat a woman with either a previous: . :,tiiillbirthi or at least one prior infant weighing less than 2,500': grams, at liirth was significantly more likely to have a future stillborn infant riian a woman witlioutsuch an, obstetrical history. After previous 0i,.,xetricalhistorywas controlled,smokerostill retained ai statistically: ~i(rsifiicant increased risk of subsequent stillbirth as compared to non- ~nu0ltiers (P<0.01). Of further interest was the, finding that among Nvomen who previously had delivered only living infants, weighing over 2,500 grams; cigarette smoking had no influence on the stillbirth~ ratie: Previous experimentall studies were reviewed in the 1971 and 1972 n-ports on the health consequences of smokin:g(101,,102),, Theauth:ors (lFinonstrated that exposure of' pregnant rabbits to, tobacco, srnokeand pregnant rats tc large doses of injpcted nicotine resulted in, a signiff- cant increase in stillbirths(7;8;,23; 87)., STILLBIRTH SVJibLARY 1. The results of recent studies suggest that cigarette smoking is most strongly associateell tiv ith a higher stillbirth rate among women who possess less favorable socioeconomic surroundings or an unfavorable previous obstetrical history. In the United States, black women have higher stillbirtli, rates than «hitewomen:. The finding that cigarette smoking is associated with an even greater difference between the stillbirth rates of the two groups merits speciall attention. These findings may provide at least a partial explanation for the lack of ai significant difference in stillbirth rates between smokers and nonsrnokers, which some investigators have found. 2. The results of'experiments in animals demonstrate that exposure to tobacco smoke and some of its ingredients, such as nicotine, can result in a significant increase in stillbirth rate. nzs

Late Fetal'anel Neonatal Death8 ConsidErable variation has~~ occurred~ in~ the definition of'the~ study~ population among the~ studies in which the relationship~ of~ cigarette~ smoki~ng~ to~~ fetaL mortality~ (other~ tHan~~ abortion) and~ early infant~ mortality was examinedL The most commonly identified study popula- ti'ens, ~ have been perima,ta~ll deaths, neonatal~~ dea~t'hs,, and late fetal plus neonatal deat~hs:~Perinatal deathsare a~combination of'late~fetal deat~hs~ (,i.e~.,,stillborn i'nfa.nts~)~~ and deat!h~s,occurrinb within the~fi'rst week of' life.~ Neonatal deaths include~ all~ deaths~~of~ liceborn infalYts~ within the first 28 days of life:. FJPIDEMIpI o('ICAL SrLTDIF,S tifost~of~the earlier~epi'demiological studies of the association between cigarette~ s:noking and late fetal plus ~~neonatali mortality w~ere~ reviewed in~ the: 1971 and' 1972'~ reports on t!h~e° health consequences~~ of smoking ('1n'1, 102). A revietiv~ of previously unreported' stud'~ies~ (67, 76), as~ weTli as~ reexamination of preu~~iou~~sly~ cited' studies,, forms~ tlre~ basis of' the~ following statements : The results~ of several prospective and' retrospective~ studies~ indicate~ a statlistically~~ s~ignificant~ higher 1at~e~ fetall and/~or~neonatal mortality~ for the infants of' smokers compared to those of' nonsmokers (~1:/; 17;. N:3~.¢3)~.~T'he results~of other~prospective~and'retrospective ~stud'nes iden- tified no significant difference~ in the~ mortality~~ rates~~ between: the in- fants fants of smokers and nonsmokers (20,~F~<5, 7'3;, 85, 100~~, 115~)~. If mortality rates.; ere compared' for those infants of smokers and' nonsmokers weighing less than 2.500 grams, the infants of nonsmokers apparently had a~ considerably ~ hi bher ~ risk ~ tli~an ! did those of ~ smokers.. Th~e~~ resu~ltsof recent st~udiesi~ coupled' with a critical revie«~ of~ the design and analysis~ of~ previous~ studies, and a reexamination of~ exist- ing data, m~ay~~ provide at~ least a partiali esplanation~ of~ discrepanciles~ between the results of previous studies.. Comparisonsaf' the lfortalit' v ~ kisks~ of Low-B'i'rth-Weiriht Infants Born toStnokersun~d Nonsmokers Theperinatal' perinatatmortaliinfantsn•eighing, less than 2,500 grams appears to be Iower for those infantsborn to women who smoke ditri~ng pregnancy than for those horiv t'o nonsmokers (table 1126

Iudy ~tte ~ant ilus hs I o f' klhe III I 3)., fIIoR-ever, available evidence shows that cigarette smokers'' i'nfants tend tohe, small4or-gest<ational age rather than gestationallypre- matlure. Hence, within a given birth .zeight group,, the infants of .fnokers are, on the average, gestationally more mature tlian those of' nonsYnokers. Data collected bytlie National Centerfor H'ealthSta- tisties (703)~ d'emonstirat'e that wit'hina given birth weight group, theluore gest~ationalIy mature an infant, the lower is its mortality risk (fig. 6). Thus; the difference in perinatal mortality ri'sks experienced 1,v theinfantsof cigarette smokers and nonsmokers, within~comparablelnrtli weight classes, reflect~s thefacts that the: two setsofl infants are not of the same average: gestational age, andi that gestat~ionall age is a major factlor infliiencing late fetali and neonatal mortality. An accu- rate est'iinate of' comparative mortality risks for the: infants of cig- arette smokers and nonsmokers~ requires adjustment for gestational af-T:e_. For infants of comparable gestational age, lower birth weight i's asr sociatedi with higher mortality (fig. 6). Since infants of cigarette ~mokers llave;, on the: average, lower birth weights than the infants of nonsmokers, within groups of comparabl'egestationall age, cigarettesutokers'' infants should experience higher mortality rates than nan- <nroke rs"Inf'antsof'simidar gestational ages-f n: a~~ recent review,A!Teyer.md Comstock (51) provided a more extensive discussion of these hoints. I 'I'ABLE 3.-Comporison of the: perinatal' mortality, for infants weighing less than 2,500 grams,, of smokers and: nonsmokers Perinatal mortality rate (deaths per.1,000 live births) Author, reference Smokers I+7dnsmoWers L'nderwood, et al. (100)---------------------- , 187 269 Ontario Department of' Health (67):------------ , 232' 300 Kullknder and Kallen (43)-------------------- 129, 139, IRantakallio (76)--------------------------,--- 288' 344 Yerushalmy1(112)~:Black women--------,---,---,------------- 114 202' White! women--------------,------------- 114 218. Butler and Alberman, (14)-------------------- 269 284 I' Reported neonatal mortality rates only. 127

Figure 6,-Neonatal mortality rates among single white' births in hospitals (by detailed birth weight and specified gestation groups: United States). ~. JANUARY 11 TO' MARCH 31,,1950' 1 ~~28'-3'1 weeks ` `. _ 32-35'~ weeks ~ ~ « . `~ 37 weeks and ouer : w • .M M « .~ ._ ..~~ 4, 11 u c c . . 1 ..i0~ .y~0, 0~. .~:0, -4O' a~.0'~ .yi O~~ ~p Ou'3~. ~ O O~tCJ: tCf~~.O~ O S ~[7h n0 ON NU) Ldh f~O' OiA .-i ,.;Ni NNi N N C11itlV~ N M~ fl7 c+'i BIRTH WEIGHT (ini grams)'. 400' 200 100 80' 60'. 10 8 SOURCE: U.S. PublicNealth Service„Wistional CenterfarHeatthiStatistics(103): Recent Studies The Ont'ario PerinataI bfortality Study (66;, 67) was conducted' among~ 10! teaching hospitals during~ 1960, and 1061.~ In this~ retrospec- tive~~ sthtdy~ of 51,490~~ pregnancies,, a statistieally~ significant increase in the perinatal mortality rate~ was, demonstrated for~ smokers" in- fants as compared with those of nonsmokers; the infants of smokers experienced an overallrel~atii-.e~ risk of 1.2'7~ (P<0~.001)~. 117foreover,,tli~e~ investigators found a,stati~stical2y~significant d~ose-response~ re'lat'ionship~~ between, the amount of~ ciga'rettes~smoked and the perinatall mortality ~ rate (P<0.001) (fig. 7). 128

Figure 7.-f?erinatal' mortality rate per 1,000' total births by cigarette smoking category. L" L 27.7 (0 t! O. r 23.2 Nonsmoker Number of periratall deaths: 659 <1i pack of cigarettess per day 425 33.4 ~_- 1 pack of cigarettes per daN 220. Total births:: 28;358! 15,328 6,581 (P C0:00T) , SOURCE: Ontario Department of Health (66). Recently ~ Butler„ et aL (15) further analtyzed the British Pdrinatali Mortality Study. They found' a highly significant association between maternal smoking after the fourth month, of pregnartcy and both late fetal and neonatal deaths. Infants of smokers had an increase in the late fetal~ mortality~ rate of' 30 percent',, and an increase~ in the~ neo~-- natall mortality rate of~ 26~~ percent„ compared to: the i:nfant,s, of' non- smokers.. The overall mortality ratio of late fetal plus neonatall deaths was 11.28 I (P<0.001I). Given the large number of women in the study; a~nd the, significant changes~ in smoking~ behavior which occurredyv they fonnd~ it~ possible t'oconsider~~ the~~ effect of a change in smoking 129

behavior between the beginning of' pregnancy and the fourth month on~ late fetal and neonatal' mortality. A statistically,~ significant and' dose-related increase in mortality occurredl among the infants, of inothers who~continued to~snioke~after~the fourt~hi month of pregnancy, as compared with the infants of nonsmokers and those of women who smoked prior to the: pregnancy but gave up smoking by the fourtlu month of gestation. Niswander and Gordon (63) reported dat'a, from the prospective Collaborative Perinatal S'tudy~ of the National Institut~e~ of Neurologi- cal cal Disease and Stroke. The 39;215 pregnancies registered at 12 uni- versity hospitials in~ the Unitedi States~~ .were~ almost equally ~ dividedl between black and white w.omen~,, Ti hey~ found a nonsignificant increase~~ in perinatall mortality among tiie inf ants of white smokers as compared t~~o~ those~ of w.hi~te: nonsmokers;~ the~ overall mortality ratio was: . 1.13 ~ ( P>Q:1)'.. The infants of' blacl: smokers, however, had a significantly highe~r~ mortality~~ risk than: did~ those~ of black~ nonsmokers'~;~~ the mor- tali'ty~ ratio~ was~~ 1,1'8 (P<~©.02)~. 'Moreov~~er,~ a defi'nQte~ dose-response re~-~ lationship~ between cigarettes smoked by pregnant mothers~ and mortality~risk was~shown for black infants. Bdack~ Nvomen were~not~ed ta smoke~ s~i;taificantly~ fewer cigarettes, on the~ a~v~erage~,~ than white~ women. Rush andi I%ass~~ (;82)~ found, iiYa prospective~~ study ~ of 3,276 ' preg- nancies folliowed, at Boston City IlIospital,~ a nonsignificant increase~ iiu late fetal plus neonatal mrtal~i'ty~ rate~ among~ the infants! ~ of wMilte~ women who~ sTnoked' as~ compared to~~ tlsose~ of u-hite~ nonsmokers, How-~ ever, the infants of'black women who smoked hadia statistically sig- ni~fica~nt, increase in mortality rate compared to~ the infants~ of' black~~k nons~mokers~ (P<~0.01)~. The overall mortali'ty~ ratio~ for bl~ack~ womeni w~~li~o~~ smoked was 1.86: Ti he difference in frequency~ of'stillbi'rt!h among~, the infants~~oY smokers~and!nonsmokers~~was~the prirnary~factor which contributed& to~~ the~ signi'fieance~ of the~ diffQrence, in~ mortali'ty~ rates. Analysis of Previously Reportedi S'tudies Prev~iously~report'~edstudoescanbe,div~~idedi~nt'o~~two~groups~: _t group in which the~ late~ fetal plus~ neonatal mortality~ rates~~ for~ iirfints born, to~~ cigarettle~ smokers, were significantly higher than those~ for, the infants born to nonsmokers, and, a group in which no significant ditferences~ we~re! detectedl in the~ mortaluty~ rates for the infants bornn to smoker.s, ~and, nonsmokers. The ~results°of~several stadies~~ (14. 17, 25, 55;,84; 92) yieldedi m~ortalitv~ ratios rangin(r ffarni L3'8~ to: 1.78. The result's of other~ studies (20. G-5.~ 7'6. 87, l00~;~ 115) yiel~ded'y mortali'ty~ ratiosrangisig~~ from 1.01 to 1.0i~: Both groups contained' retrospeetive~ and proshect~ive~studies:of~ comparable, size. The two groups did differ i'30

th W bf' e ~il<ruii3cantlyr; hotiti-ever,~ti•ith regardl to control of variablesother than (-i-;a•ettesniokinb whichintluenceperinatal mortality. 1'actors~ «'hich~ Influence~ P'erinatal \Iortality~ Other Than Smoking liutller and Alberman (13),: on da~ta from tlie~ British Porinatal' ylortttility~ Study, emhloyed a 1bgi~t transform~ation analysis of'variance;. ;ui~d dernonstrated that mate~rnall hei9lit, age„ parity, soeiall class, andl ~-cvere~ preeclampsi'a all had a significant independent effect on~ late fx>tal and neonatal mortality. Rumeau-Roquette (81~)~ provided evi- (lencetllatai previous~st~illb~i'rth or~l'o.v~-birtli, «•eightinfa,ntsign2ficantly~ increased the~~ risk of~ a future stillbirth. 'Mey,er and Comstock (51~~)' i)rov~ided exam~plles,of~ho.r the diffe~rentiall distribution of smoking and. ,>tlier~flactors«-hi~ch, are~related to:perinatal mortality, in a population L)f Nroznen, can bias data (e:g., black women have higher perinatal iu„~rtality rates tlhan~ do~~ white: women,~ but black~ women smoke, less t4ati white women do. 1-Ience„ nonsmokers will tend' to include more N)lack~ .v~oiuen,~ and slmke~rs, more~~ «-h~ite~~ women. Thu's~ will tend to~ reduce: any differences between the groups in mortality rates.) Meyer and C:omstock~ concluded,~ "Comparisons,of~ mortality~ rates of smokers'~~ and nonsmokers' babies should be made within subgroups according to parity, socioeconomic st!atus, and other appropriate risk factors, aud not separated by~ birth~ .veight."~ I'n three of~~ tlhe~ studies in which a~, sign~ificantly~ higher~ mortality risk ~ was demonstrated for the infants of smokers; adjustment for other variables~ was~ performed. The~ results~ indicated that, after such ad.-~ jitstment„ a significant independent association between cigarette sinoking and infant mortality persisted (l3' andl 15, 17,, 81). Of the studies Which revealed no significant increase~~ in mortality risks forr smokers'~ infants,~ one (115)~ controlded! for race~ alone. Hence, at least~~ part of'the: discrepancy~ in results~ between tihe~ two~~ gl•oups~ of~ studies may be etplai'ned by a: of'control of variables other than smoking. Another possible, at least partial, explanation of the discrepancy in results obtained by the two sets of studies is that cigarette smoke may be: more harmful to the fetusesof certain women than, others. Several de~velbping~lines~of evidence suggest that this!may~belhe case;~ 1~.~ Ciga~rettesmoking~andsociioeconomic~background.. Butler, et al. (15) noted that when data from the British Perinatal. lliortality~~'StudV ~ are~ groupedl by social class~~ of~ the~~ mother's~ husband, the late fetall plusneonatal mortality ratio for infants of smokers and nonsmol:ers in the upper social classes I and II i's 1.110; the mortality ratio for the: entire sample: was 1.28. Rus1i and Kass (82): reviewed the British Perinata~ll liortali'ty~ S~~tud3-,~ along, , R ith several ot~h~er~ studies, and noted that all have shown the strongest association between excess infant mortality and ci'garette smoking among the infants of those 495-028 0-73-10 1i31i

mothers with lower socioeconomic status. Comstock andi Lundin (16) found excess mortality among, smokers'' infants almost entirely con, fined to those whose fathers had a, grammar school education or less. Several of'the studies wliicli revealed no, significant difference in mor- tality among the, infants of smokers and nonsmokers were conducted in predominately middle class populations (20;100;115). 2. Cigarette smoking and previous obstetrical'egperience. Peterson, etal.(72) had rigidi criteria for entry into, his study population of 7,740 women. He included only those women who pre- viously had healthy infants with a birth weight greater than 2;500 grams. He found a significant decrease in birth weight among smokers' infants, but no significant increase in mortality rates. Rumeau- Foquette (81) found that among women who previously had delivered only healthy infants weighing more than 2,5C)0' grams, cigarette smok- ing was not associated with an increasedl risk of stililbirth ;~ among those, women with a previous stillbirth, smoking was significantly associated with increased risk of a f'uture stillbirthL 3. Cigarette, smoking and genetic diff'erences. T1ie eonsistentfind2ng that the mort'alit'y risk for tlie.infants of blackk smokers is higher than the risk for the inf'ants of' whi'te smokers, even when the socioeconomic background for both: is~ ostensibly similar, suggests that genetic factors also may interact: with smoking to pro- duce enhanced risk (82, 99, 115). A:vaiiable evidence suggests, that if' those women,, who are already likely to have small infants for reasons other than smoking, smoke during pregnancy, their infants willi be most unfavorably affected. This means that the women in the United States whose infants will be most aff'ected by cigarette smoking are:those who have an unfavor- able socioeconomic situation, ha:ve a history of previously unsuccessfull pregnancies, and are black. E%PPRIbfE _r'TAL ..~'rI'D3ES' Studies in AnimalS Studies previously reviewed in the 1971 and 1972 reports oni the health consequences of smoking (101, 102) demonstrate that exposure of'rabbits: and rats to tobacco smoke and& to~ injections of large doses. of nicotine resulted in significantlly increased late fetal' and neonatal mortality. Astrup (2) has recently studied the effect of continuous exposure of pregnant rabbits to carbon monoxide on stillbirth rates. He found a significantly higlier,, dose-related incidence of stillbirths and deaths within thefirst 24' hours of life among the offspring of the experimental rabbits('table 4'). T32

T:~I3t-E 4.-E-ffe~et~ of' carbon monoxide exposure~ of ~ pregnant rabb'i~ts~ on b'i,rth ~ we ight and ~ neonatal mortality Group 1, Group 2;, Group 3, 0percenG 8 to 10 percent 16to18pereentCOHb COHb COHb tudy , pre. 3,500' kers, leau, ered inok- hose ited *k wen ilar, )'ro- idy ake !ed. -Vi1'1. or- ful. ;he ire. 5es al us !s; iss le Number of' pregnant,rabbits------------ 17' 14 : 17~ 11,,ta1 number of'babiesL ---------------,- 1116' 81 1!23' rtillhorn and' ~ babies, ~ died with~infirst 24 huurs------------------------------ t 1 z' 8' a 44 (E<q:001) ~ 1. peree~,nt: :.10~ perc~~ent. - 36 peroent. 5uurce:: Astrup.:P• (I)i~ Studies in H'umTns Some investigatiors~ have~ examined' the~ causes o~f' death among the infants of'smokers as comlaared with those of nonsmokers. Comstock, ct al. (17) found that infants of smokers died more frequentlyy of' as- phyxia, atelectasis,,and immaturity. Kullander and Ka12en (43) ~ f'Gundd abruptlio placentae~~ signifi~cantly~ increased as a cause of~ death~ am~ong~ smokers' infants. Bntler~and Alberman~ (14)1 found' little~ difference~ in~ the~ death rat'es~ for the inflants~ of~ smoke~rsand nonsmokers from iso- immunization and malformations, but higher rates were found for srnokers'~ in~fants~~ in the~~ groups~ in~ which~ death occurred before~ or ~ d,ur- ing labor, or in which death resulted from massive pulmonary hemor- rhage, or pulmonary infection. As the authors noted, "The latter three: are conditions known to be associated with small-for-dates babies:''" They pointed out that distribution of causes, of'~ dea,th~ in the~~ sm~oking, group could be accounted for almost entirelyrby the exc.ess of low-birth- weight ba'bi'es., Th~is~support'sthe~ conclusion that the~ mechanism whieh~ a ffects birth weight al'so~influences mortality. SIG15i IFICANCE' OF. THE' ASSOCI ATION The fallowi~ng~calculation is offered to~gil•.esom,e~idea of t'he~order of magrn~itude~ of increased late fetal and neonata~l~~, mortal'ity~ associated w~it1l ci'garette smoking during~~pre~;ixancy. If Nvomelr who smoked dur-

ingpregrlancy in the United, States had an elevation in risk of 28 per- cent for late: fetal and' neonatal mortality, as dcrrionst'rated by Butler,, et a1. (15) for Britain, Scotland,, and' Wales, and if 20 percent of pregnant women smoked throughout the pregiiancyyl the higher risk of'stil'lbirth and neonatal death, for the infants of m'others who smoke cigarettes during pregnancy would account for approximately 4,600 of the 87,263 stillbirth and neonatal deaths in the United States in 11968. LATE FETAL AND rVTFO'ZV'ATAL DEATH SU3131A$Y A strong, probably causal association between cigarette smoking, and' higher late fetal andi infant mortality among smokers' infants is supported by the following evidence : 11. Twelve retrospective and prospective studies have revealed a sta- tistically significant relationship between cigarette smoking and anelevated mortalityrisk amongthe infantlsof smokers. In threeofl these studies, of sufficient size to permit adjustment for other risk factors, a highly significant independent association between smokng and'mortality was ~established. Part of the discrepancy in results between these studies and those in which ai significant association between smoking and infant mortality was not dem- onstrated may be explained by a lack of adjustment for risk fac- tors other than smoking. 2. Bvidence is convergingto suggest that cigarette smoking may be more harmful to the infants of some women than others; this may also, in part,,explain the discrepancies between the results of the studies in which a significantly higher mortality risk was shown for the, infants of smokers compared to those of nonsmokers and the results of those studies in which significant differences in mortality risk were not found. 3. Within groups of similar birth weight, tlie infants ofl nonsmokers appear to have a higher mortality risk than do the infants of' ciga- rette smokers. This results from the fact that the infants of non~- smokers within such similar birth weight groups are' on the average gestationally less mature than the infants of' cigarette smokers. Available evidence indicates that within groups of sim- ilar gestational age; infants of lower birth weight experience a higher mortality risk. Since the infants of cigarette smokers are I Based an extrapolatiom of data on smoking behavior change during pregnancy from the British Ferihatal Mortality 9tudy; which probably yields a conservative estimate.

er- ler,, of' isk ke of' 68. !g is smalMor-gestational age, one should expect that if theinfantsof' cigarette smokers and nonsmokers are compared within, similar gestational age~ classes, the~ infantsof' cigarette~ smokers would have the higher mortality rate. 1. The results of'recent studies have documented a statistically sig- nificant dose-response~relationship between the number or amount of cigarettes smoked and late fetal and neonatal mortality. 5. New data suggest that if a woman gives up smoking,by the fourth inonth of pregnancy, she will have: the same riskof~ incurring a fetal or neonatal loss as a nonsmoker. f,; Avai1'ableevidencestrongdysupports cigarette smoking as one cause of fetal growth retardation. The causes of' excess dea.t'hss anonb the infants of' smokers~ are those associated with small- for-dates babies. ;. Data fronl experiments in animals have demonstrated that expo- sure to tobacco~ smokeorsome~of its, ingredients, such as nicotine or carbon monoxide, results in a significantincreaseinl'atefetal and or neonatal' deaths. S. The results of studies in humans have shown that the fetus of a smoking mother may be directly exposed to agents such as carbon monoxide within tobacco smok~e;, at levels comparabletothosewhichIhavebeen shown to~prodh.tcestilllbirth inexperionental' animals. Sex Ratib, 9 0 _Ylthough a number of small studies have found a, slight, usuallystatisticallynonsigpificant,increasein the proportion of female infants born to snlokers„the three~largest studfiesof'Underwood,et al., (418;505F: pregnancies)~,Butller(15',791 pregnaneies),and Mac'M'~ahon (']i2,1155, pregnancies) have found similar infant sex ratios among, both smok- inm and nonsmokiilg: mothers, withtheetpected slight excess, of malesalnOn(r each (tlble5). Suonm-ary Arail'ahle~~ evidence strong~ly~ i'nd~icates that maternal cigarette smok~- iRig do:,s~ not inftnence the sexrat'ib~of newborn infants. 35 135 9 9 0

71`ASLE 5.-P'roportian of' made infants d'elivered' ta smokznq dnd' non, smoking rrcotfCers Author reference Pre na cie Proportion of male lntants Stat'istical i ifi , g n s Smokers rihon- smokers c gn cance Underwood, et al. (100)_--..-------_---- 48,505 .518 .519 None. Butler and,Alberv:nan (1'4)-------------- , 15,791 . 518 .516 Do. IG'1ac1VDahon,, et aii (49)-----,------------ 12, 155 .513 .512 Do. Kullander and Kallen (13) ------------- 6,363 ' .515 .501 Do. Reinke and I'lenderson, t(78)------------ 3,,156 .,49B .517 ' Do. Frazier, et al.t (2'~6)--------,---,-,--------- 2,915 . 472' . 505 Do., (P >-0.05) Kizer (4$)---------------------------- 2, 095 .502 A93 ' None. Herriott,,etlal. (36)-------------------- 2,745 .492 .517 Do. Ravenholt, et a1 (77)------------------- 2,052 .501 .533 P<0.05 Lowe (46)'---------------------------- 2,042 . 532 .529 None. Ritssell} et a1. (83)--------------------- 2, 002 .513 .512 Do. I Black women. Congenital Malformations Previous epidemiological stud7es which examinedi the relationship. Betw,een cigarette smokiiig and congenital malformations were re- viewed in the 1971 andi 19'72 reports on the health consequences of' srnoking (101,,102). Recently, the authors of the Ontario Perinatal Mortality Study (66, 67), a retrospective study of' 51,490 births, re- ported no, difference in malformation rate for the infants of' smokers and' nonsmokErs. The various studies of the association between ciga- rettesmokingand congenital malformation have differed'signifieantly with regard tostudydesign, the type of ' population sampled, sample size and number of infants with malformations, the deffnition of` mal forrnati~on, and results~ (;tabTe6')~. Previous experimental workk wasreviewed' in the 1971 and~ 1'972' reports on the health consequences of smoking (101, 102). The chsck embryo has been empioyed in recent studies, Thedi'reet application of' nicotine to tlhee embryo results in cephalic hematomas (26), , malforma- tions of the cervical vertebrae (93), and anomalies of the heart (27), depending, upon dose of' nicotine and period of incubation in which eaposureoecurs: Anomalies of't1ielimbs of chicken embryoscan~ alsobeinduce& byexposureofithe egg to high levels of carbon monox- ide U). 136

~al ce D5)' x 'fnBLE' 6'.-llelati.ue risk of congenital malforr>zati.on for infants of e~'rtarette~ smok'ers~ and nonsmokers, comparing available studies~ with rr~garrl to study , design, st~udy~ popula:tion,, sample~ size, numb~er~~ of ~ infants' with malfae•matinns,~ a'nd~~ defi,nitibn of malformati~on Author, Study~design~~ Study~ population~ re ference . Sample size Infants with malfor= mations Relative risk Definition,af' SSijNS malformations Lo,ve -------- Retros;pective. Stillborn plus 24-hour h dp 2,042 23 1:36, Major. at s. ('crostock, et al. ----- do--------- Neonatal deaths-----,.-, 230 37 .31 bfaJpr, cause of death 1'erushalmy(11E): Prospective.-- Infants,Iess than. 695 59 . .57, Illajon. 2,500 g. 0=1.tario D'epait- Retrospective-, Stillborn plus 1st« 51,,490 1,744 .97 c:ent of,Ilealth week deaths plus 7). survivdng infants;. P•,ulerand kl- do--------- Stillborn plus neo- 7;123 1,382 1.19 bia)or„cause of1 t;€•iman (14). natalldeaths. death.. liullsnder and Prospectit e---, (a) Stillborn pluss neo- natal deaths plus remainder 137 43I 1125' taJor' and minor Sslnn (.yJ). ofldeaths, to age malformations: 1. (b) Surviving infants to age 1. 4; 903 700 1.06 edrick, et al. etrospectlve_ (a) t!Stillborn plus neonatal deaths r and deaths to age l,t'sur- vlvors 3 to age T. 1'7,418 88' 1.55 (1). (b) i Neonatal deaths r (3-month study). 7,822 ' 204, 1107 (o). t kntopsyproven congenital cardiac malformationi %Clinically determined congenital heart disease. Congenital 3lal f'brmation Summary. Given the considerable variation in study desib y study population, sample size, number of' affected infants; definition of malformation, and results, no conclusions can be drawn about any relationship betcveen, maternal cigarette smokin;, and congenitaL malformation at thepresenttime: 137'

Lactation Introduotion The following, section is a review of available evidence which bears upon any interaction between cigarette smoki;ng and'] actation. Empha- sis is placed upon the relationship of cigarette smoking to the quantity, of milkproduced, tothe~ presenceof' constit'u~entsofcigaret'te,smokewithin the milk, and to effects upon the nursing infant medRatledd throughi changes, in either the quantity of milk available or the sub- stances within the milk. Epidemiological Studies: Underwood, et al., (99), in a study of 2,000 women from various sociall and economic strata, observed a d'effnite but statisticaldyy insig- nificant trend toward more frequent inadequacy of breast milk pro- duction among, those smoking mothers who attempted tla nurse compared to nonsmokers.Mi12s (52)1„ini a study of 520 women, found that among womenwho irid'hcatedi either a desire to nurse or no desire to nurse yet continuedl to nurse beyond 10 days, and who had delhuered their first 1i've-born infant, t'he! average period of nursing for mothers who smoked was significaiitly shorter than for nonsmokers,, 1i'oreover, among the 244 mothers w hohadgiven up smokingduring, at least the fina13! mont'hs of' their pregnancies,, the average length of' nursimg wasid'ent'iical to that of tlhe nonsmokers: There was no~ significant difference between smokers and nonsmokers with regardi to complete inability to nurse thei'roffspring. This study isdifl'icult to, interpret because the author did not determine the reason(s) for the discontinuation of nursing, among the women. Experimental Studies STiJDIEs! . I-N ~ A~riPI1MTAP,s~ Nicotine Infl'uence on the Lactation, Process Blake and'i S'awyer~ (12)~ studied the~ influence of subcutaneously i'njected& nicotine~ (4 mg~. total over a 5~~-minute~~ period) upon lactation in the rat.~ They found that nicotine inhibited the suckl2ng-ind'uced! 138

iears pha, itityaokey ated sub- ious sig- >ro- irse. ~ vho iied brni ,vas 24 ths l' to een ;rse hor ing Jy :)n ~d rise in prolactin, Noeffect of injected nicotine wasd'ernonstrat;ed for osytocin secretion since milk release was not blocked. Wilson (110) examined the effectis of nicotine supplied through ,lriillkingwater (0.5, 1.0, and 2.0 mg. daily) on the weight gain of nu2-sing rats. Apparently, the nicotine had been available throughout (restation as «-.ei'1„because tlie~authorcommented on a redluction in litter size among the experi2n.ental' groups; more or lpss proportionate to the (lose of nicotine; hence, a prenatal effect could not have been dis- tiiig-uished from a postnatal one. Average birth weight was similar for i-xperimentall and1control groups. No difference in weight gain was seen f„r any of' the groups. The lack of impact on birth weight suggests that dbse was lower than that used in other studies.. Presence of' Nicotine in the Milk Hatcher and Crosby~~ (32)~, using~a frog bioassay, reported traces~of'~ nicotine~ in cohv's~ milk ~~ 24~ hours~ after, the~ intramuscular~ injection of :0 mg:/kg. and 5~ hours after~the injection of'0.5~mg,/kg, Etridence for an Effect Upon the Nursing Offspring. Hatcher and Crosby (32). found that 0.5 mg./kg. nicotine injected into nursiing catls had no apparent harmful effect upon the kittens. _1;pparently4.0, mg:/kg: suppressed lactation. Kittens fed the milk fromf the cow which had been injected «ith~ 5J mg,/kgnicoti'ne were also apparently una ffectled. Nitrosamines Mohr (,53)found that , diethylnitrosamineand dibutylnitrosamine, when administered to lactating hamsters, were associated with the cllevelbpment'of' typical tracheal papillary tumors in the young; sug- gesting passage of' these compounds in -the milk. Although diethyl nitrosamine and dibutylnitrosamine have not been identified in ciga- rette smoke, many N-nitrosamines are potentcarcinogens, and some of them are present , in cigarette smoke (37, 79)':. Srun>Es i_N~ I+IIImAws Nicotine and/or Tobacco Smoke Influence on the Lactation Process Emanuel (22) noted no reduction in, milk production among 10 wett nurses who were encouraged to smoke seven to 15 cigarettes daily; 139

~ some were observed to inhale the smoke. Hatcher and Crosby (32) ; noted that after a mother smoked seven cigarettes within 2' hours, it "' was difficudt to obtain a specimen of breast milk. Ferlman, et al. (71) ` found that of' 55 women smokers with an adequate milk supply at the ~ beginning of his study;,11 (20 percent) of the women had an inade+ ~ qpate supply at the time of discharge from the hospital. No relatibn- ° ship: was reported between the nusnber of' cigarettes smoked andd the ` likelihood of developing an inadequate milk suppliy:. The authors' im- ~ pression was that there was no greater proportion with an inadequate milk supply amongsmokerstlian among nonsmokers, but no, cor- roborating datai were supplied. Presence of N'icotine in the Milk. Hatcher and' Crosby (32): found', using a frog bioassay, that the milk of' a woman collected after she had smoked seven cigarettes ini 2' hours contained approximately 0.6 mgr jliter nicotine: Emanuel (22), using a leech bioassay; studied excretion of'nicotine in the milk of' wet nurses who were encouraged to smoke for the experi'ment: After the subject's had smoked six to 15 cigarettes over a 1- to 2-hour period,,the author found nicotine in their milk 4 to 5 hours after smoking,,withia maximum concentration of 0.03 mg./liter. Bisdomi (70)i demonstrated' nicotine in the milk of a mother who smoked 20' cigarettes & day. Thompson (97) found approximately 0.1' mg./liter of nicotine in the milk of a mother, who smoked nine cigarettes a day (plus three pipe- ful's),. Ferltnany et al. (71), using, a Daphnia bioassay, demonstrated nicotine in the milk of all!women who smokediin their study. Moreover, they found a direct dose-relationship between concentration of nicotine and the number, of' cigarettes smoked. No comment is made by the authors on the possible inaccuracy introduced by egamining, only the residuall milk following nursing, but it is well known that the composi, tion of the fore milk and hind' milk is di~fferentand perhaps, t'heconcentration of nicotine also differs.. Evidence for a Clinical' Effect Upon the Offspring Emanuel (22) ' noted' that among the infants in his study, loose stool's were observed only in the one whose wet nurse had smoked 20 ciga- rettes in the previous 4 hours. Bisdom (10) observed a case of "nico- tine poisoning" in a 6-week-old infant whose mother smoked 20 ciga- rettes a, day. The symptoms ineludedi: restlessness, vomatin,g;,diarrhea, and tacliycardia. Nicotine was d'emonstrated in the milk„ and the symptoms abated when smoking was stopped! Greiner (30) also de- scribed a case of' possiblenicotinepoisoning in a 3-week-old nursling, 140

~ (32) ,. )urs, it ~. (71) at the nade+ a.tion- d the y'' iin- q;uate ~ cor- t the ~' lin 2 22), ~ ~ the ~ the ~ th~ ~ted ~ ~ay. t'he. ipe- lted ver, tine the ~Ghe tisi- :tlie ols ,>a I 10- .a- 'a, ze e- ig whose mother~smoked3~5~to~40ciga.rettes~a day. The~sy.rn~ptom,s,incl'uded A,..onliting~~ and l'oose~ stools~. Fallowing~ the~ curtailment of ~ slnoking, the~ s~-.inhtoms gradually abated over a 3 day period. Perlrrlan, et all (71) noted no effect of~ smoking, on the weight gain of the infants, of'the~ ~1nokers in their study., P'urtherrnore„ no untoward symptoms were ubserved. They therefore doubted an effect of smoking on lactation., 1'hcv~ noted' that the dose: recei'ved by the infantls~ was beneath the toxic I«vel as computed~ from adult experience; and this~~ accordedl with~ their clinical observatli'ons. The: fact that they admitted to the study only wonsen with an apparently~ ad'equate~ milk supply~ m~~ay~ have~ affected tiieir~ results. The~~authors~~ suggested that perhaps,the~laek of~effect of s~uioking ~ upon lactation might represent'~ the development of tolerance~e to ~ nicotine,, as botih the mother and the offspring hadl been egposedd thr.oughout'the pregnancy.. VITAIILIN C Venulet (105, 106, 107):, in a series of studies, demonstrated that flie level of v.itlaanin~ G was~~ reducedl in the m~ilk~ of smok~ing, mothers as conipa~red with nonsmokers. The~ clinical significance of this observaltion has not been evaluated., Lactation Swmmary~ 1. The two pertinent epidemiological studies suggest ai possible: in- fl'u~eneeofsmokingupontheadequacyof'milksupplyI+I'owever,, with onIylimit;ed numbersof'women and without control ofotherpotent'ially significant variables,, no conclusions can be drawn. 2: Studies iQi, rats have demonstrated that nicotine can interfere with suckling-induced rise in prolactin. The relevance for humans is uncertain. 3: Evidence exists that nicotine passes~ into breast milk. No: . clear evidence f©r ani acute effect upon the nursing infant i's available: Potential chronic effects havenot been studied. 4. ivenvevidencefrorra experiments with m ~ice suggests that nitros- ainines., known carcinogens, pass through themilkt'~osucklin,gyoun~:

Pneedampsia Previous epidemi'nlogical studies of the relationship betR-.een cig- arette smoking, and preeclampsia were reviewed in the 1971 and 1972 reports on the health consequences of'smoking (1tJ1;102) and form the, basis of thefollo«ing, statements':'The results, of several large prospective and retrospective studiess indicate a statistically significant lower incidence of' preeclampsiaamong smoking women (14, 43;.1fJ0). The results of one large retro- spective study d~emonstratedl a significant inverse relationship between the incidencee of preeclampsia and the number of' cigarettes smoked (10(J)~.When other risk factors,silchaspari'ty, social class, maternal weight before the pregnaney, and maternal weight gaiili during the pregnancy were controlled, smoking women retained a significantly decreased risk of preeclampsia (21),. The lower riskofpreeclampsiak for cigarette smoking women, has been demonstrated'' in Britain and Scotland' (14,, 21, /8, 83), The United States (100, 118),,Venezueia ('42)'.,andl Sweden (43);.1[f a maternal smoker doesdevelop preeclamp- sia, ho«ev.er, av.aiIable data suggest that her infant has a~ higher mor- tality risk thani does' the infant of' a nonsmoker with preeclampsia (21;,83). Sum,mary 1. Available evidence indicates that maternal, cigarette smokers have a significantly lower risk of developing preeclampsia as compared to nonsmokers.. 2. If'awoman w_hosmokes cigarettes, during,pregnancydoes developpreeclam:psia, her infant has a higher mortality risk than the infant of a nonsmoker with preeclampsia. Pregnancy B;eferences. (1~). ABERLPATHY,, J... R„ GBEENBERG„ B. G:,, WELLS, H... B..,FRAZTER;, T. K slnolCingg asans independentt variable in a multijllee regression anal.ysisupon birth weigfit, and gestation. American Journal of Public Health and the Nation's Health 56'(4) : 626'-633,' Apri1 1966.. (2) Asxatur; P. PathoIogische Wirkungen massiger Kohlenmonoxid-T{on¢en- trationen., (Pathological effects of'moderate carbon monoxide concentra- tions. ) staub-Reinhaltung der Luft 32(4) : 146~-150, 1972: (3Y BAtLEY, R. R. Theeffeetof maternal smoking on theinfanti birth weight_ i9ew Zealand Medical JournaD 71(456) : 293-294, May 1970. 142

n ¢'ig- I 1972 mi thee udies ~~' ~ rlpsia :, ~ etro- ~ tireen k . okedd ernal ~ ~ r the tntly lpsia and uela mp- uur- J rSm IS '"r. (4')i BeKER;, F. D:, TUMASONIS, C. E: Carbon monoxide and avian embryo- genesis. Archives of Environmental Health 24(1) : 53-61, January 1972. (5) BARisALD, L., YACOUB, M., FAURE, J., ~IALIYAS, Y., CAU, G. L'oxyacar- bonemi'e de Lenf'ant n@ de mere fumeuse. (Presence of' carbon monoxide in the blood of'a child born of' a smoking mother.): :ifedecine Legale et. Dommage Corporel 3(3) : 272-274',, Ju15-augusti-September 1970. (6)', Br;AL, V. A. Nutritionall studies during pregnancy. Journal of the Ameri- can Dietetic Association 58(4) : 321-326, April 1971. (7): BECKER, R. F., Kz:va, J. E. Studies on nicotine absorption during preg- nancy. II. The effects of' acute heavy doses on mother and neonates. . American Journal of Obstetrics andl Gynecology 95(3) : 515~-522;, June, 15,1966. (3) BECKER; R. F:, Liz-rLE„ C. R: D., KixG, J. E. Experimental studies on nicotine absorption in rats d'uring,pregnancy!: III. Effect of subcutaneous, injection of small ehronic doses uponimother,,fetus, and neonate. Ameri- can, JournalofObstetrics~and Gynecol'ogy,1100(7) : 957r968, Apr. ii, 19681(J) BECKER, R. F., riTARTIx, J. C. Vital effects of chronic nicotine absorption, andl chronic hypoxic stress during pregnancy and the nursing, period. American Journal of Obstetries andi Gynecology 110(4) : 522-533, June 15,19711 (10) BisDom4 C. J. W., Alcohol and, nicotine poisoning in infants (sucklings), ~Iaand§ehrift voor Kindergeneeskunde 6: 332-341, 1937L (11) BLAKE, C. A., SAWYER, C. H: Nicotine blocks the suckling-induced rise in, ci'rculating prolactin in lactat!ing, rats. Science 177(4049) : 619-621,, kug.18, 1972. (12) BUNCHERS, C. R. Cigarette smoking, and duration of! pregnancy. American. JOurnaUof Obstetrics and Gynecology 103(7) : 942-946;, Apr: 1, 1069„ (13) BUTLER, N. R.,,ALBERxAN, E: D. (Editors), Perinatal Problems: The Sec- ond Reportl of' the 1958' British Perinatal Mortality Survey. London, E. and S. Livingstone, Ltd1,1969, 395 pp~ (14) BUTLER; N. R.,, ALBERMAN, E. D. (Editors). The effects of smoking in ;'ers i as lop (ii5) (16) the M. 9is nd n-, t. pregnancy. Chapter 5:, In: Perinatal Problems. Edinburgh, E. and S. Livingstone,, Ltd., 1969,,pp. 72-84., BtTLEx, N. R., GoLDSrErv, H., Ross,, E. M. Cigarett'e smoking in preg- nancy: Its influence on birth weight and perinatal mortality. British Medical Journal 2'.,127=130; Apr. 15, 1972., Co.csrocK, G. W.,, LusDiw, F. E., Jr. Parental smoking, and perinatal mortality. American Journalof' Obstletricsandl Gyncology 9'8(5)~:708-r 718, July 1„19G7. (17) CoMsTocK, G. W., SaAH, F: K., MEYER, M. B., ABBEY, H. Low-birth weight and neonatal mortiality?rate related tomaternaI smoking, and socio- economic status. American Jburnal, of' Obstetrics and GSnecology 11i1( li) : 53--59, Septl 1, 1971. (18) CoxrEV; A. H., WEr,cH,, R., KuNTZStANS R., CHAqG, R., JACaasor, M., _lTUtiROFAURII,. A. D., PECK,, A. W.,, BYE, rL.,, POLAND, A..,, POPPER6, P'. J.,. FiNSrER, Woc.FF, J. A. Effects of environmental chemicals on the metabolism of drugs, carci'nogens;, and normal body constituents in man: AnnalS of the New York Academy of Sciences 179;~ 155-172, July 6, 1971. (19) DoMACALA„ J., DaacAaALA, L. Zachowanie sie wagil urodzeniowej oraz czestosc wystepowania wczesniactwa I wadl «•rodConych u noivorodkoxvkobietpadacychl tyton. (Birth weight and incideneeof' prematuritsand congenital anomalies in newborns of mothers smoking tobacco. ) Pedi- at'riaPolska, T.47(6) :735' 7'38;,1972.. 1'43

(20) DowN¢rPa, G. C., CHAPMAN, w., E. Smoking and pregnancy. A statistical studyy of 5,65Wpat'2ents. California Medicine 104(3) : 187, March 1966. (21)1 DuFSUa;, G., 3i., 3lacGu,LiVRAY„T.,The incidence.of preeclamptic toxaemia in smokers and nonsmokers. Lancet 1(7550) : 994-995, 3iay 11, 1968: (22) EMerruer., W. Uber das Vorkommen von Nicotin in, der Frauenmilch nach Zigarettengenuss. (On the presence of nicotine in breast milk fol- lowing the use: of cigarettes.) Zeitschrift fiir Kinderheilkunde 52':, 41~- 46,1931. (23) EssENnESG,, J. 14T., SCHWIND, J. V., PgTRAs, A. R'. The effects of nicotine andicigarette smoke oni pregnant'female albino rats andl their offsprings; Journal of' Laboratory and ClinicaP .1Tedicine 25 : 708-717, 1940. (24) FeniucK, J,, Ar.aEastart, E. D., GOLDSTEIN, H. Possible teratogenic effect of' cigarette smoking. Nature 231 : 529-530;, June 25,, 1971'. (25) FsAzax, T. M., DAVIS, G. H:, GbznsTEiN,, H., Goc,DHEan; 1: D: Cigarette smoking, and prematurity :, A prospective study. American Journal of'~ Obstetrics and G'y!necologg81(5) : 988-996, BTa91961. (26) GATSirra, R. R. Effeet of nicotine on chick embryo. Archives of'~ Pathology 78 :, 652-657, December 1964. (27) Gir.Amr, S! H. Nicotine andl cardiogenesis. An experimental study. Pathol- ogia et Microbiolbgia 37(5) : 383'-39io;1971. (28)~ Gbr.nsTm:r, H., GOLDBERG, 1. D., FhAZtEu, T. M., DAVIS, G. E. Cigarette smoking, andl prematurity. Journal of' the Ameriiran OBteopathic Asso- ciatibn 64 : 541i-549; January 1965. (29)~ GouJASn„ J., ETIENNE, C., EVRARD, F. Caracteristiques maternelles et poids de naissance. (Ji'aternal characteristics and bi',rt'h weight.) Revue dui Praticien19'(29,,Suppl'ement) : 54„59--62, 65;N'ov. 1, 1969. (30) GeeirrER,, I. Nikotinvergiftung, beobacbtet bei einem Saugling. (Nicotinee poisoning observed in a breast feeding infant.)' Jahrbuch f'ur Kinder- heilkunde 146: 131-132, 1936. (31) HADDON, W., Jr., NESBIT, R. E. L.,, GARCIA, R. Smoking and pregnancy : Carbon monoxide in blood during gestation and at term. Obstetrics and Gynecologyl8(3):: 262-267, September 1961. (32) HnTCaEB, R. A., Chosav, H. The elimination of' nicotin in the milk. Journal of' Pharmaceutical and Experimental Therapy 32(1) : 1-6, 1927. (33) HawoxTfr, J. C,,, FORD, J. D: Comparison of the effects of maternal under- nutrition and exposure to cigarette smoke on the cellulhr growth of the rat' fetus. American Journal of Obstetrics and Gynecology 112(5) : 653'- 656, riTar. 1, 1972. (34) HE$orr, H. J., The effects of smoking during pregnancy : A review withi a preview. New Zealand 1ledical JournaP 611: 545--548,, November 1962. (35) HesxzoTm, A., Bn.LUwiCZ, W. Z., HYTTEN, F. K Cigarette smoking in preg- nancy. Lancet 1: 771-773;,Apr. 14, 1962: (36)~ JAavrNEN, P: A., OsTExLUNn; K. Effect' of'smoking during pregnancy on the fetus, placenta and delivery. Annales Paediatriae Fenniae 9: 18-26, 19M (37I) JoHNsox; D. E., RHOADES, J. W N-nitrosamines in smoke condensate from several varieties of tobacco, Journal of the National Cancer In- stitlute 48(6) ~: 1845-1847, June 1972'. (38) JucxAu, bi: Rl Human placental hydroxylation of' 3,4-benzpyrene during, early gestation andi at term. Toxicology and Applied Pharmacology L8(3) :, 665•'-675, March 1971. (39)K£irrTr, C: H., TusHS P. G. Measurement of thetotal' smokeissu~ing, from a burning cigarette. Tobacco 160(15) : 26-29, Apr. %196r;. 744

titistical !h 1966. )xaemia 1„ 1968. !nmil'chi ilk fo1- i2': 41L KisG; J. E., BEOKER, R. F. Stud'ies oni nitoti'neabsorptiion d'uringpregnancy. I. LD. for pregnant and nonpregnant rats. American Journal of Ob- stetrics and Gsnecology 95(4) : 508-514; June 15, 1966. ( ~1) KiRscHnAuzi, T: H., DILTS, P. V., Jr.,, BRrVKMANy C. R., III: Some acute effects of smoking in sheep and their fetuses. Obstetrics and Gynecology 35 '(4) : 527-536, Apri11970: ~ti ) KrzER,, S. Influencia del habito de ftrmar sobre el embarazo, parto p recien nacido: (Etfect, of the smoking habit on pregnancy, delivers,, and the newborn.) Revista de Obstetricia y Ginecologia de Venezuela 27(4) : 59 r-6-43, 1967. i .;,3 ) KULLANDER, S., KALLEN, B'., A prospective study of smoking, and' pregnancy. Acta Obstetricia et Gynecologica Scandinavica 50 (1)~: 83-94; 1971. (~ y) KusiAR, D:,, ZoURZAS, P: A. S!tudies' on human~ premature births. II. In vivo effect of'smoking and in vitro effectl of' nicotine on human uterine contractility. American Journal of OO bstetrirs and Gsnecology 87(3) :' 413-417, , O c t. 11, 1963. (:~5') LONGO, L. D. Carbon monoxide in the pregnant mother andl fetus, and its exchange across the placenta. Annals of the New York Academy of Sciences174(1) : 313-341, Oct. 5, 1970.~ (aC) LOWE, C. R. Effect of' mothers' smoking habits on, birth weight of their children. British ltedical Journal, 21:, 673-676, Oct.10, 1959. (+7) McIDosaLO,, R. L., LArFoRn, C. F. Effects of smoking, on selected clinical ,x obstetric factors;, Obstetrics~ and Gynecology 26(4) :', 470-475; October poids 1965. h du . (48) '-NTcGARRY„ Jl `i., ANDREWS, J. Smoking in pregnancy and vitamin, Bi,: I metabolism. Btitishi Med'ital, Journal 2:74-77s Apr. 8~1972: Dtine (,j9) MACMAHON, B'., ALPERT, M., SALRER, E. J. Infant weight and' parentall ~der- Rc3':. smoking habits. American: Journal of' Epidemiology 82(3) : 247-261, November 1965. (50) MANTELL, C: D. Smoking, in pregnancy: The role played by carbonicanhy- ;and drase: New Zealand M'edicalJournal 63: 601-603, September 1964.. rnall (5i) .1TeYER, M. B., CoasTOCK, G. W. Maternal cigarette smoking,and perinatal mortalit'y: American Journal, of' Epidemiology 96'(1) :, 1-10, July 1972. (SZ )_11ILLe, C. A. Tobacco: smoking Some hints of its biologic hazards Ohio der- State: Jipdical! Journal! 46(12) : 1165-1170, December 1956: the F53- (53) ll'oHR, U.,,ALTHOFe, J. C'arcinogenic activity of aliphatic nitrosamines via the mother's milk in the offspring of Syrian Golden hamster% , Proceed- ings of the Society for Experimental Biology and Medicine 136(3D :' ;h a, 1007-1009, March 1971!. (5y): '.NlUK'.HERJEE,, S,,, 1'IUKHERJER,. E. N: A study of premat'urebiEths., Indifln: reg- Journal! ofl Pediatrics 38'(285):: 389-392, October 19711. ~ on (55) liUr,caHY; R:, KNAGGS, J. F. Effect of age, parity, and cigarette smol:kingg on outcome of'pregancy. American Journal of Obst'etrics and Gynecology 6, 101(6)1:844-849,,Ju'1y,15;,19fi8!, (56) MULCAHY, R., MURPHY, J. :Viaternall smokingandi the ti~mi'ng' of delivery. te Journal of theLri'sh Medical, Association 65(7) : 175w177; Apr. 1 , 1972, 11- ,, (57):iTrneA.Hr, R'., MURPHY, J~, 11iARriv, F. Placental changesandl maternal ig s weight in smoking and nonsmoking, mothers. American Journal of' Ob- stetrics and Gynecolbgy106!( 10f70$'-7Q4,,3Tar. 1„1970,. (.58) JILRnocH, D. E; Birth weight and smoking, Nebraska State Medical Joun- nal!48(111) : 604-606,ri'ovember 1~963. (59) MURPHY, J. F.,,JI'uccAHy; R. The effectl of age, parity, and cigarette smok- ing oni baby weight. American Journal of Obstetrics and Gynecology 111! (1) : 22-25, Sept. 11, 1971. 1'45

(60) NeLL, J. F. Complexed cyanide in collected' cigarette smoke. Abstracts of' 20th Tobacco Chemists Research Conference, Nov. 1-3, 1966, «'.inst'on- Salem, N.C., 1966', pp. 26'-27. (61) . NEHERT, D. W.,. WIPPKER;. 1, GELROIK, H. V. Aryll hfdrocarbonhy.dro%ylaSen activity in human placenta from cigarette smoking and nansmoking, women. Cancer Research 29 (10 ) 1: 1763-1769, October 1969. (62) NawsoalE; J. RR., NosalArry V., KEI2II, C. H. Vapor phase analysis of tobac- co smoke. Tobacco Science 9: 102-110, July 23, 1965. (63) NiswAnDER; K. R:,, GORDON, M. Section 1. Demographic characteristics. Cigarette smoking. In: The Women and Their Pregnancies. The Cbl- laborative Perinatal Study of the National Institute of Neurological Dis- eases and' Stroke. Philadelphia. W. B: Saunders Co., 1972,, pp: 72-80. (64) NoRMA.wV.,NiZwsoxiE; J. R., KeIrH, C.` H'. S'mokingmachines for the, analysis of' the vapor phase of cigarette smoke: Tobacco Science 12: 216-221, 1968. (65) O'LANE„ J: M, Some fetal effects of' maternal' cigarette smoking. Obstetrics and Gynecology 22(2): T81I-184; August1963. (66) ONTARIO DEPARTMENT oF'HEALTH. Second Report' of' the Perinatal :tior- talit5 Study in Ten C'nikersity Teaching Hospitals. Toronto, Canada, Ontario Department of Heal~th„OntarioPerinatal 'MortalitsStud'yCom- mit'tee,, vol. L, 19674 275 pp. (67) OSTARIo DePARTrsENT aF HEALTx. S1ipplement to the Second Report of the Perinat'at .l'Iortalit'y Stud'y in Ten University Teaching Hospitals. Toron-to;Canada, , Ontario Department of Health, Ontario Perinatal 'Mortality Study Cbmmittee, vol. 11, 1E167;.pp, 95-275_ (68) OsBORNE, J. S., ADAMEK, S., HOBBS, 3I. E. Some components of gas phase of cigarette smake. Analytical Chemistry 28(2) : 21T-215;, February 1956. (69) OUNSTED, M. JI9 t'ernal constraint of foetal growth inman. Developmental Medicine and Child Neurology 7: 479-491, October 1965. (70) PAybzcsEx, B., WALLANDER, B: Cigaret'tr6kning och abort. Konsekutiv pros- pektiv undersokning av 4312 graviditeter. (Cigarette smoking and abor- tion. Consecutive prospective study of 4,312 pregnancies:) Lakaratild+ ningen 6F(,22);: 2611-2616,~ May 26,, 1971'. (71) PERI,MAx, H. H., DANNENBERG, A. 1T.,, SoxoLOFF, N. The egcretion of nieotinee in breast milk andlurine from cigarette smoking. Journal of the American Miedicali Association 120 (13 )~: 1003-1009, Nov; 28, 1942. (72) PETERSOl\, W. F., ?IZOREBE,. K. N.,. I1,ALTREIDER;, D.. F: Smoking, an(1~ pre- maturity. maturits. A preliini'naryreport based on study- of 7,740 C'a~ucasians.Obstetricsand Gynecology 26(6) : 775-779;, December 1965. (73) PETERSsoev, F. Miedicinskai skadeverkningar av rokning. Rokning, och bv nek:ologisk-obstetriskatillstand. (Harmful clinical effects of' smoking. Smoking andl gyniPcologi'cai-obst'etrical condition.) Social-Medicinsk TidSkrifti 2( Speciai No. ): 78-82, February 1971l. (7h,)PxiLIPPe~ R. J., Honas;lf. E. Somecomponent§~ of thegasphaseotcigaret'te smoke. Analytical Chemistry 28(42):2002=2005~ December 1956'. (75) PRImRosE~ T.,HInoINS. A. Astudpin human antepartitm nutrilhioniJournal of Reproductive,:YTedicine 7(6) :257-264', December 1971. (76)R'ANTAKALLIO, P:,G'roups at Risk: in P.owBirth Weight Tnfants and'. Perina-taI Mortali'tc. A prospective stmd',r of tire biological characteristicsand socioeconomic ci'rcumstanceq of' mothers in 12;000 deliveries im North. Finland 1966. A discriminant function analysis. Acta Paediatlrica Soandinavica (S'upplement193)~: 1969, 71'pp: 146 6.

eristfics; 'he Col' cal Dis- :'-80. for the. ~Ce' 12: 6tetrics iI Dior- anada, ~ Com« i ,of the, 'poron- ,tality ase of. ! 1956. tental', pros, abor- rrtid- -otine rican i pre- dans. ~ by- king. !insk B of qber ion: Ina- !nd rth; ica (',i7). RAVENHOLT, R. T., LEFIN81f1; 1K'_J., NELLI6T,, D. J.,. TAKENAGA, M.. EffeCts'f of smoking, upon reproductioni American Journal: of Obstetrics and Gynecology 96(2) :, 267 ?&1, Sept. 15, 1966i, REi` xE, «'; A., HENDERSON, ai. Smoking and prematurity in the presence of' other variables Archives of Ehvironmental Health 121(5) : 600-606, May 1966. 179) RxoaDES, J: W., JoHNsoN, D.,E. ;tletbod for the determination of ti-nitro< samines in tobacco-smol:e condensate. Journal of the National Cancer Instlitute48 (6) : 1ti4'1'-184I3;,June1972. ii'~O) RanIxsaN;, P. 'Yshwn nshymi B'wrmmywtvzmn hhrswn wh~shp'tw '1 h,m, h'n br .vhyl«-d1 ( SinokdngbyBurm~ese women during pregnancy and its influence on the mot!her, the fetus and the newborn.) Harefuah. 69(2) :!37-39; 1965. (q'1)~ Rvv4e:au-RouQUETTE, C., Gotrs'ARO, J_ KA'MINsxr, M., SeaWAaxz;, D! Mortalite perinatale en relation avee les antecedents obstetricaux et l'usage dtr tabac. (Perinatal mortality in relation to obstetric antecedents and tobacco: usage.), I'aper' presented atl the Third European Congress of'Perinatal Medicine, Lausanne, Apr. 19-22,' 19~72',8'pp. (6') Rusii, D:,,IiAss, E. H. \iaternal smoking: A reassessment of the associa~ tion witihiperinatai mortality. AmericanJournallof Epidemiology 96(3) :183'-196,, September 1972'. (83) RUSSELL, C. S,, TAYI:oR;, R., LAW, CJ, E. Smoking in pregnancy, maternall blood pressure, pregnancyy outcome, baby weight and growth, and other related factors. A prospective study. British Journal' of Preventive and S'ocialA'ICdicine 221(.3) : 119;-1'26„July 1968:01'-~) RUSSELL, C. S., TAYLOR, R'., 31,AnnISO~, R: N. Some effects of' smoking im pregnancy. Journal of Obstetrics and Gynecology of the British Common- wealth 73 : 742-746, October 1966. (,85) SAVEL, L. E., Roxa„ E; Effects of smoking in pregnancy! : A continuing retrospective study. OO bstetriesand Gynecology 20(3) : 313-316, Septem- ber 1962. (SH)~ SCxcEnE; E., IEEeKEe, H.-J. Effect of benzo(a)py,renetreat!ment on the benzo(a)pyrene hydrox;T•lhse activity;' in maternal liver, placenta, andd fetus of' the rat during day 13 to day 18 of' gestation. tiaunSn-Schmiede- berg's ArchivesofP'harmacology272'(.1):R9-100, Dec. 21„1p71. (S7) CCIroE-NECK, F. I. Cigarette smoking in pregnancy. New York State Journal of V'IedLcine 41: 104:5r1948; Oct. 1, 1M1. (88) SCOPPETTA, V. Sul contennto di assido di~ carbonio nel sangue circolante digestantilf'umatrici;. (C'arbonimonoxidecontentin tbeblood ci'rculatingin pregnant smnker~s~.) Archi'M1•iodi Ostetricia e Ginecologia 73(3) : 369-375, Slac-June 1968'.. (8'9)SiEnQe; S. 35., E:aseo, S. Identification of dru'g9in thepreimplantation, blastocyst and inithepl'asmas uterine secretion andurilneof'the pregnant, rabbit. Journal of Pharmacology and, Ekperimental'Therapeutics 176(1):: 63-75; 1b71.(9/X)SY'xePso:v, W . J:, A preliminary report on cigarette smokingand' the incidence of prematuritg., American Journal of Obstetrics and Gyne- cology 73(4): 808-815. April1©57. (91) SPEARS. #'.W:.RouTii:, W. E. A, combined approach to thequantitativeanalrsis of tlieviolatilecomhonents,ofl cigarette smoke. Paper presented! at the1'8th TobaccoChemist's Research Conference, Raleiglt, N.C., 19641 495-028 0-73-11

~ (92) STEELEy Et., ILANGWORTH,, J. T. The relationship~ of! antenatal and post- natal factors to sudden unexpected death in infancy. Canadian Medical Association Journa194: 1165-1171, May 28; 1J66! (93) STRUDEL, G. Action teratogene du sulfatedenicotnne sur1'embrson d'ee poulet. (iTeratogenic aetion, of' nicotine sulphate on, chick embryo.). Comptes Rendus Hebdomadaires des~Seances de 1'Acadamie des Sciences;: D: Sciences Naturelles 272 (4) : 673-676, Jan. 25; 1971. (94,). SUZUKI,,K., HORSGUCIII,,T:, C.oNIAS-tiRRUTIA, A. C.,, IrUELLER+FIEUBACII, E.,. JiaRISaISIA, H. O'., ADA.IsoNS, K., Pharmacologic effects of nicotine upon the fet'us and mother in the Rhesus monkey. American Journai', of Obstet'rics and Gynecology 111(8) : 1092-1101i, Dec. 15; 1971. (95) TERRIS, M., GOLD, E. M. An epidemiologic stiudy of prematu:rity. I.,Relati;on t'o smoking, heart volume,, emplbyment; and! physinue. American Journal of'Obst!etricsand'GSnecolbgy 103(3) : 358'-370; Feb. 1, 1969! (196i)'TtiIENEB;, C. H., IAM:BARD, C. F:,, FIELDING, F:, J.,, LESSER;. A'., J.,ELLEN- HoRN, M. J. Alterations in reproductive functions of white rats asso- ciated with daily exposure to nicotine. Journal of'~ Pharmacology and'. Experimental Therapeutics 87: 1-10, 1946~ (97) THOMPSON, W. B. Nicotine in breast milk, American Journal of Obstetrics and Gynecology 26: 662-667', 1933. (98)~ T.YaLVE, H., bIANSSON, E., ScHaIITERLOw, C. G. Passage of "C-nicotine and its metabolites into mice foetnses and placentae: ActaBharmacolbgica et. Toxicologica 26(6) : 539-555; 1968. (i99)~ UiNDERWOOD;,P. B., HES'TER,P,,I..,.LAFITTE, T.,.Jr:,, GREGG, K.. V..The.relation, ship of' smoking to the outcome of pregnaney., American Journal of'~ Obstetrics and Gynecology 91(2) : 270-276, Jan. 15; 1965.. (a'00)i UNDERWOOD, P: Bl,, KF.SLER,. K. F., O'LANE, J...M., CALLAGAN, Dl. A.. Parentall smoking empirically related to pregnancy outcome. Obstetrics and' Gynecology 29(1) : 1-8, January 1967.. (101) U.S. PUBLIC HEALTH SERVICE. The Health Consequences of' Smoking. A Report of'the Surgeon, Gleneral : 1971. Washington, U.S, Department of, Health, Education„ and'Welfare,, DHEW Publication No. (HSMQ71-751% 1971, 458pp, (102) U'.S. PUBLIC HEALTH SExvrCE. The Health Consequencesi of' Smoking. A Report of' the Strrgeon General : 1972. Washington, U.S. Department of Health, Education, and Welfare, DHEW Publirationi No. (HSM) 72-7516, 1972, 158 pp. (IO8) U..S,. PUBLICHEALTH'. SERVICE. NATJONA'L, CENTER FOR. HEALTH, STATISTIC6. Weight at birth and survival of the newborn-United States;,early 1950. `Vashingt'on;, U.S: Departtnent af'HeaIth„Education, and!1Velf'are, Public Health Service Publication No: 1000, Series 21,, No. 3, July 1965,, 33 pp. (104) VABA, P., KiNNUNEN, O. The effect of nicotine on the female rabbit and develbping, foetus: An experimental study. Annal§ Medicinae Experi- mentalis et Biologica Fenniae 29 : 202-231, 1951. (105) VENULEm, F. Nastepstwa niedoboru witaminy c u palaczy. (Consequences of' vitamin C'de8ciency in smokers.) Poisltie Archiwum Medycyny Wewnetrznej' 26 : 393--402, 1956; (106) VE:vUI:ET, F., LAUSZ, H. Ubytek witaminy c w narzadachi zab podd'anychh dzialaniu dymu tytoniowego. (Influence of tobacco smoke on ascorbic acid' content in moth,ers' milk.) Acta Physibl'ogica, Pblonica 4(4) :351- 356, 19541 (107) VEVULET, F', DAxysz, A. Wplyw palenia tytoniu na poziom; witaminy c w mleku KobiecTln. (The influence of tobacco smoking on the level of vitamin C in human milk.) Pediatriai Polska 30(9) : 811-817, 1955! i4:8

I post- edi~call bn de' iryo. ) nees',, ~ btihee ial oL' lation tirnal k.LEN+ !asso- i and Ftrlhs IE and' ica et tion- IL of' fnthl and I g. A 't of 6,lIi) ~, AA it of' ~ ~res. f 950. 01ic f' pp.' ~nd p'erl- pces Oy lpch kbic' I I51- ew I of (108), li'Er.cH„ R: M., Go,&mir, B, ALVaRES, A. P'., CoNNEr, A. H: Effect'~ of enzyme induction on the metabolism of benzo ( a) pv!rene and 3-methgl-4- monomethy-lgminoazobeneene in the pregnant and fetal rat. Cancer Re- search 32(i5) : 973-978; May 1972. f, 109.), WELCH, R. =IT.,, HARRr60N,., Y.,E:., GoAY3['S,. B..W.,, POPPERSy P. J., FtN6TER,. M., CONNEY, A. H. Stimulatory effectaf' cigarette smoking on the hydroxyla- tion of 3;4-benzpyrene and the N-diemethviation of' 3-methyi-4-mono- methylaminoazotienzene by enzymes in~ human placenta. Clinical Phar- macology and Therapeutics 10(l)1:100-109, January-February 1969. (110) «'rLSaN, EJ W. The effect of'smoking in pregnancy on the: plaeental' coeffl- cient„New Zealand13iedical Journal 74I(475) : 384-385, 1972. (111) «'Y:vnFR,, E. L., HOFFMANN, D. Tobacco and Tobacco Smoke: Studies in Experimental Carcinogenesis. New York, Academic Press, 1967,, 730 pp. (112), YERUsHALarY,, J. Infants with low-bi'rth, weight born beforethei'r mothers started to smoke cigarettes. American Journal, of Obstetrics and Gyne- cology 112 (2) : 277-284, Jan. ].I5, 1972'.. (113 ): YEfaLSHALatY, J. Mother's cigarette smoking and surrivaU of infant. Ameri- can Journal of Obstetrics and Gynecology S8;(4) : 50;r518; Feb, 15,,1964,. YeRUsH Ar:My, J!: Statistical considerations and eralhiatiom of'epidemiolbgf~ eal evidence. In: James, G., Rosenthal, T. (Editors). Tobacco and Health. Springfield, Charles C. Thomas, 1962, pp. 208-230. (115) YERUsHALarr, J. The relationship of parents' cigarette smoking to outcome of'pre,gnancy-implications as to the problem,of inferring causation,fromn observed associations. American Journal ofl Epidemiology 93(6) : 443- 456;, June 1971. (116) YbuNaszAi,, M. K., KACLC, A., HAwoRTHSJ: C. Cigarette smoking~ during pregnancy: The effect upon the hematocritt and acid-base balance of the newborn infant: Canadian 3ledical Association Journal 99(5) : 197-200,~ Aug. 3, 196& (117 ) YocNOSZAi, JT. K., PELOSO, J~, HAWORTH, J. C. FetaU growth retardation in rats exposed to cigarette smoke during pregnancy. Americani Journal of' Obstetrics and GS necology 104(8) : 1207-1r?13, Aug, 15,,1969. (118) ZARRrsxrE, J. R. Effect of' cigarette smoking during, pregnancy. Study of 2;000 cases. Obstetrics and GynecolbgS 21(14)1:405-411, April 1963. 149'

Pe.ptic, Ulcer, Disease

Page Introduction-------------------------------------------- 155 Epid'emiological and Clinical Studies---------_---_--------- 155 Experimental Studies Grrstrie Seeretion _------------------------------------ 157 Pancreatic Secretiw ---------------------------------- 1159 Summary of Recent Peptic Ulcer Disease Findings-_-------- 162 References--------------------------------------------- 1163 List of Figures Figure 1.-Ga.strie ulcer mortality ratios of Japanese (men and Nromen combined) by age at initiation of cigarette smoking (1966-70) -------------------------------------------- 156' Figure 2'.-Effect of' cigarette smoking, on volume of secretin- stimulatedd pancreatic secretion in humans_--------------- 160 Figure 3.-Effect of cigarette smoking on seeretin-stimulated, pancreatic bicarbonate output in humans----------------- 161 ' 151

Introductim Previous epidemiological and experimental studies of'the relation- ship between cigarette smoking and peptic:ulcer disease were reviewed: in the 1971 and 19?2 reports on the health consequences of smoking ('Ii;.Z8)andlform! thebasisofthefolloaeingsummary: Tlieresults of epidcmiol'ogical studies indicate that cigaretit'esmok- i ng males have an increased prevalence of peptic ulcer disease , andl a -reater mortality from pept'icul'cer ascomlpared tononsrnoking males. Among males; the association betvveen cigarette smoking and peptic~~ ulcer disease is stronger for gastric than for duodenal ulcer, but sig- nificantfor bot'h.For males, cigarettestaoki'ngappears toreducetheeil'ectiveness of standard peptic ulcer treatment and to slow the rate of pepticulcerhealin~g. The: relationship: between cigarette smoking and t'.he prevalence of and mortality from peptic ulcer disease is less clear for females than for males.Experiment.al studies of'the effect of cigaret.te smoking ini man, and of'the effect of injection and infusion of nicotine in animals, on gastric eecnetion and motility have produced confti'ctin~g resul'ts: In dogs, an infusion of nicotine has been found to inhibit pancreatic and hepat'ic bicarbonate secretion, thus demonstrating a possible link betweenn cigarette sniokingand dhodenal ulcer:, R'ecently,, additional epideYniological,, clinical, autopsy,,and experi- mental studies have confirmed then association between: cigarette smok- in- and gastric ulcer mort.ality and have clarified a mechanism through which cigarette smoking might be linked to duodenal ulcer: EJpid'demiological an& Clinical Studies Previous studies of'the relationship between peptic uleer disease and cigarette smoking have been conducted in, predominantly white, West- ern populations. A large prospective epidemiological study is currently being conducted in Japan. From, thisstudy, Hirayama(6)' reported .5-year folloti<<up data on 263,118 menn and women, aged 40 years and old'er,,representing 91 to 99 percent of the totall popnlation in the area of the 29healthi districts in .vhieh the study was conducted. Both male A I 0 a I 0 I 0 a a 9 I

an& female cigarette smokers experienced higher d'Ieath rates from gastric ulcer as compared wi6.h~ nonsmokers: The mortality ratio for cigarettesmokers was 1.81 for males, (F'<O.QOl)and 2:15' for females(R'<O:fJ5).The morta:l'ityratioforsmokers(rnales' and femalescom- bined) was dose-dependent as measured by age at initiation of'smoking (fig. 1)., Theresultsofl this study, i'nthecontextof'the genetic and cul- tural differences between Japanese and lVestern populations, provide a significant confi rmation of the association~ between cigarette smoking and gastric ulcer mortality. Figure T.--Gastric~ulcer mortai'ity ratios of'Japanese (men and womenicombined)n bx age at' initiation oficigarette smoki'ng,(196Cr197t1), 5.00 4.00 1.00 0 Nonsmoker SOURCE: Hirayama, T. (6). 1156 >25 <24 <19 Age at initiation of'cigarette smoking (yrears).

i I from~ ;io for 4 Oales t com= oking 7' al cu1- ~' lovide '£ oking Alp, et al.(1) conducted a retrospective survey of 638 patients, admitted to two Australian teaching hospitals between 1954 andl 1963, with: chronic gastric ulcer confirmed by roentgenographic, endoscopic, or surgical examination. The findings in the patients were compared with information available about the South~ Australian populationn obtained at census in 119'51 and 1961, and with a~ control group of 233, subjects matched for age and sex with the ulcer patients. Cigaret'te, tise, a family history of peptic ulcer, domestic stress, and aspirin and alcohoL intake occurred significantly more freqpzently among ulcer patients. Alp, et al. (2)1 found that after surgical treatment, recurrence of the ulcer was significantly more likely to recur among those patients wllo continued to smoke, drink, and use aspirin (P'E0.001).Fingerland, et al. (5) compared the autopsy findings from, 76'5'males with their smoking history. The autopsies were performed without selectibn during 1965 and 1966' at the University of Hradec Kralove, (: zechoslovakia. P'ept'ic ulcer was significantly more frequent among male ex-smokers andi male lifelong smokers than among male non- smokers (P<0.02)~. Among males, a dose-response relationship was~ found between estimated total cigarette consumption and the presence of peptic ulcer at autopsy. Cooper andi Tolins (h) reported results from a retrospective study ofl the relationship betR een cigarette smoking andl postoperative eom- pliications arnong 2,988 :males, admitted to 19 V'eteransAdministration hospitals, for the su~rgicall treatmentof' duodenal ulcer. S4noking, his- tory was obtainedi for 1,4411 of the men,, and of' these 273 were non- smokers, 1,018 smoked cigarettes only, and 93 smoked' cigarettes plus a pipe and/or cigars. The authors found no evidence:of an association between either the number of cigarettes smoked per day;,or the number of years ofl cigarette smoking, and postoperative complicati'ons, opera- tive mortality, or length ofl hospital stay. They emphasized that their results, must be viewed with considerable caution and listed several potential sources of' bias. Iin addition, they noted, `'`* **' that these results apply only to the immediate postoperativefi'ndings and do not apply to the lbng-range effects of' smoking upon the patient after surgeryy f'or duodenal ulcer disease." Experimental Studies Gastric Secretion STL7DIES I.N HIID'iANS Morales,, et al. (10, 11) studied the effect of cigarette smoking on gastric secret'i'on in a group of 312 patients. The patients included 13~8'. O ~ 1i57 ~ ~ ~ ~ ~

with duodenal ulcer, 93 with gastric : ulcer, andl 81 with other gastro- intestinali disorders, who served as control§.. Cigarette smoking, was significantly more freq,uent among the patients with peptic uIcer than among the controls. The chronic effect of smoking on gastric secretion was quite variable. Male smokers among the controls and in the group with duodenal ulcers had ai significantly increased baseline acid output as compared with nonsmokers in the same groups ( P<0.05)., 'tlfter a subcutaneous injection of' histamine; only the group of maie smokers withi gastric ulcers had a significant increase in acid output over the values obtained' for nonsmokers in the same group (P<0:05'). 4mong the.smokers in the control group, the relationship between gastric acid output andithe: number of cigarettes smoked daily was dose dependlent. No such rela- tionship was obtained for either of the twolgroups with peptic ulcers.IIn. these experiments, the acute effect of'smoking on gastric secre- tion was slight. In one set of experiments, a group of eight smokers served as its own control. The smoking of two cigarettes prior to collection of gastric jiuice had no significant effect on acid output as compared to baseline values. After smoking twocigarettes, and~ alsoreceiving, a subcutaneous injection of histarnine,, the patients experi- enced no~ significant change in gastric acid output as compared to baseline values; 21 male patients, including members from t!he groups with ul'cers, and controls, smoked onecigaret'tel hour after an intra- venous infusion of histamine. A transient depression of' gastric acid, output was noted as, compared withi t'heval'uesobtained from ni'nepatient's who did not smoke. STAIDIFES IN ANI4IA7yS Konturek, et al'. (8), studied the effect of intravenous infusion of' nicotine on the formation of acute, experimental dkiodenal ulcers in cats. The authors infused nicotine intravenously in doses comparable to the smoking of four, eight„ and 16 cigarettes per hour into cats in whom near maximal gastric acid output had been stimulated~ with intravenous pentagastrin. The investigators found that nicotine in the~ two lower doses hadl no effect upon the gastric acid output stimulated by pentagastrin, but that the highest dose produced a significant de- crease in response, due to,a fall in botlhvolhime and acid concentration. Nicotine alone failed to alter a negligible basal gastric secretion. In control' animals (pentagastrin alone), duodenali udcer& were found in, eight of' 10 animals. Nicotine at the two lower dbses, in combination with pentagastrin, produced ulcers in alll 26~ animals. At theinter-mediatedose~ of nicotine, the mean ulcer area, was, twice that found in 158

i ~ast'ro- g, was n than i. ~iable.. denal pared, neous astric! n.ined ~rs in jcl the irela- lcers. lecre* ~kers ~ )r to, ut as I lal'so peri- d to )aps ltra- ! Rcid hine kof 6 in tble sin ~ith the ted de- on, i Inn inn on er- in the control group. At the: highest dose of nicotine, peptic ulcers ap- peared in only two of six animals and the areai of ulcer was reduced compared to controls. Shaikh, et al. (14) studied the acute and chronic effects of sub- cutaneously injected no:cotine on gastric secretion in rats.. Under basal conditions, the volume of gastric secretion was initially depressed, then stimulated, and depressed' again as the dose of' nicotine was increased. Acid output was decreased over the entire range of nicotine d''osage. Pepsin output reflected a similar triphasic response to in- cre.asiing nicotine doses as did gastric secretory volume. In the absence of nicotine, pentagastrin stimulated gastric volume, acid, and pepsin output. The inject'ion of nicotine„ in increasing doses, administered simultaneously with pentagast'rin, resulted in a gradual decrease in response for alli parameters.. `'olume of gastric juice, acid output, andid pepsin output werea1l increased significantly by chronic exposure to nicotine alone. Based on an average smoking dose of nicotine, the dose of nicotine employed in: the chronic experiments corresponded to the smoking of three to five cigarettes per day. Thompson, et al. (16) extended the study of rats described above by studying the effects of chronic nicotine injections in vagotomizedd rats and rats with discrete lesions in the hypothalamus. In sham- operated animals, chronic nicotine injections significantly increased baseline volume of gastric juice, acid output, and pepsin output. Fol- lowing vagotomy, the nicotine response was completely: suppressed. Caudall hypothalamic lesions did not influence the response to nicotine in the presence of intact vagus nerves. Anterior hypothalamic lesions,, ranging from the anterior hypothalamic area to the ventromedial hypothalamus, blocked the nicotine-induced gastric secretory stimula- tion in: the presenceof'intact vagi. The authors concluded that chronic nicotine-induced gastricseeretory stimulation is mediated via anterior hypothalamic, activation and intact vagus nerves. The importance of local effects remained uncertain. Pancreatic Secretion STIIDIES IN HUMANS Bynum; et al. (3)' studied the effect of cigarette smoking upon pan- creatic secretion in 23'healthyyoung,malesand females. Fi'vecontroli male nonsmokers: were compared with: seven malle and two female light smokers, (less t'~han one pack of cigarettes per day for less than 3years) and eight male andl one: female heavy smokers (more than one pack of 1~s9

cigarettes per day for more than 3' years). Pancreatic secretion was measured by the double secretin test, using Boots secretim The experiL ment was divided into two parts for the smokers: A basal collectionn period and an experimentall period during which the subjects smoked seven nonfiltered cigarettes at the rate of four per hour. Light', srnokerss had basal v.alues for pancreatiic secretory volume and bicarbonate out- put in response to secretin whi& were not significantly different from, contpols. After the subjects had smoked, significant depression of'both pancreatic volume and bicarbonate output was noted (P<.001). Heavy srnokers had basal values that were significantlyy l'ess than in the control subjiects (P<0.01). Stnmoking, however, did not further depress the response to secretin (figs. 2 and 3). Solomon, and Jacobsen (15) reviewed some possible rnechanisms whereby the increased prevalence and mortality from, duodenal ulcer among cigarette smokers might be produced'. They concluded that eviidencefromstud'ies in animals,,coupled with thefind'irrgs of' Bynum, et al. (3), supported the hypothesis that the mechanism active in humans involves impaired neutralization of acid secondary to the inhibition of pancreatic bicarbonate secretiom Figure 2.-Eff'ect of cigarette smoking,on volume of secretinrstimulMed pancre+ atic secretion in humans: N11ean volume of pancreatic fluid ini milliliters per Ikilbgram body weight 3,0 2~.5'. 2.0 11.5 11.0 0.5 0. ^ 2:9 1.51 00 1 2 bo ~.. E r" p Y E ~.. ~ E . c, 0 Z E co E W O~~ V~' lYaV)~. Z ae oa J .-1I 11 Significantly different ~ from i nonsmoking test, within group 1 of light: smokers (P <0.001). 2 Significantiy different from nonsmoking controls (P <0:01). SOURCE: Bynum~ et al. (3). 160 1.9'' 2,0'

~ was ?eri- Ition >ked. Iters& but- lnom both 01!). l! the iress I I Isms lcer tllat 6, b' in t'he I ~ (cre- i Fligure 3'. Effect of cigarette smking on secretin-stimulated pancreatic bicar= bonate output in humans. Mean hourly output of' bicarbonate in milliequiva- lents per hour 11.5' 84 551 8.1 7.12 r-1 m N ~C y~ pp Y: t16' J9 O'o c o' c o e a c 0 M ~•~ O U; Z~~~. ~~. O. VJ~ ~ Z 0~~. ~~. OI ~ E .•; N,m ~,~ u, ~ ~ z cc J J = _ i'Significantly different from nonsmoking test within group of' light smokers (P C0.001). "Significantly different, from nonsmoking controls (P <0.01). SQURCE Bynum, et, all (3). STUnrs ix ArrsMALs Konturek,, et al. (7) extended his research on the mechanism of nicotine-induced inhibition of pancreatic secretion in the dog, using the design previously emplbyedi (9)'. Infused secretin alone led to al sustained increase in pancreatic bicarbonate output. Intravenous nico- tine, at all four doses of infused secretin, produced a significant in- hibition of pancreatic volume and bicarbonate output (PG0.05). Infused nicotine appeared to inhibit competitively the effect of secre- tin on pancreatic secretion of fluid and bicarbonate. Topical (intraduo- denal) nicotine failedl to affect significantly the response to infused secretin. Stimulation of endogenous secretin by an acid infusion into the duodenum produced the expected pancreatic secretory response. Nicotine either applied to the duodenal mucosa or injjected intra- venously significantly inhibited the pancreatic secretory response to endogenous secretin. ~Ticotine had no significant effect on total pancrea- tic protein output. n?icotine did not alter the cholecystokinin-induced stimulation of pancreatic secretion. The authors concludedl that nico- tine may inhibit pancreatic secretion ofI flu'ud and' bicarbonate both 12 10 8' 6 2' 0 0 @ III 0 G

by a direct effect on pancreatic secretory mechanisms, acting as a com- petitive inhihitor of secretin,,and by a secondary effect on the duoden.al mucosa, depressing the endogenous release of secretini by acid. Robert (,12) studied' the potentiation of' active duodenal' ulcers by nic.otine adininistration in the rat. Subcutaneous infusion of pentagas- trin and carbachol resulted in the dose-dependent formation of duo- denal ulcers within 24 hours. Nicotine alone produced no, ulcers. Increasing doses ofl subcutaneously infused nicotine, in combination~ with the other two agents, resuIted' in a steadily: increasing dose-related incidence and' severity of the duodenal ulcers. Robert notedl that Konturek, et, al. (9) found, that nicotine inhibitedi pancreatic and biliary bicarbonate secretion ini dogs, and that Thompson, et al. (1Fi )~ foundl that acute dbses of nicotine in rats either depressedl or did not alter gastric secretion: He concluded that the most probable mechanism by which nicotine potentiated acute duodenal ulcer formation in the rat was via a suppression ofc pancreatic secretion. Robert, et al. (13)! further tested this hypothesis by infusing acid via the esophagus of rats in doses f'ound' to cause duodenal ulcers inn one-third of'the experimental animals. One group ~ofrats also received a, subcutaneou& infusion of nicotine. Another received nieotine;but only water was infused via the esophagus;, 31 percent of the animalb receiving acid but no nicotine had duodenal ulCers; 93 percent of the nicotine-acid group had duodenal ulcers,, whi1enoneof'~ the nicotine- water group had ulcers. The ulcers in the nicotine-acid group were more numerous,,extensive, andl deeper than those in the animals which received acid alone., Summary of Recent Peptic Ulcer Disease Findings. In addition to the findings relating cigarette smoking to peptic ulcer disease, summarized in previous reports on the health consequences of smoliing (17, 18) and cited in the introduction to this chapter, recent studies have! contributed further to our understandiitg of the association:, 1. The finding of' a significant dose-related excess mortality from gastric ulcers among both male and female Japanese cigarette smokers, in a large prospective study; andl in the context of the genetic and cultural differences between the Japanese and pre- viously investigated `Vestern populations, confirms and extends the association between cigarette smoking, and gastric ulcer mortaIity.

i I ~ Iom- ~na;i Ilby. wo. ~rs. ion ted 4at ~ndl r6), IIot sm the ;id iinn ledd fiut L'1a he le- J`e ~}1 i ~ i ar )f' a.t lie 2. Data from experiments in several different animal species sug- gest that nicotine potentiates acute duodenai ulcer formation by means of inhibition of pancreatic bicarbonate output.. 3. Cigarette smoking, has been demonstrated to inhibit pancreatic bicarbonate secretion in healthy young men and women. Peptic Ulcer Disease Refierences, (1) ALr, M. H., HisLor, L. G., GRANT, A. K., Gastric ulcer in South Australia, 1954-G3. 1. Epidemiological factors, Medical Journal of Australia 2'(24) : 1128-1132, Dec. 12, 1970. (2) ALP, M. HL, HIIBLOP, I. G., G$erT, A. K. Gastric ulcer in South, Australia, 195?i-63. 2l Symptomatology andi response to treatment. Medical Journal of'Australia 1(7) : 372-374, Feb. 13, 1971. (3) BrxuM, T. E.,, SaLOMorr,, T., E.,, JoHNsON, L R., JaCOSSON„ E. D. Inhibition of pancreatic secretion in man by eigarette smoking. Gut 13(15) : 361465, May 1972. (4) COaPES, P., TbLiNs,,S: H. Relationship betweeni smoking history and compli+ cations immediatelq following surgery for duodenal ulcer. Mount Sinai Journali of'.Medicine 39:(3) : 287,29'l; May-June 1972. (5) Fr'xaERLAND,, A., HusxK, T., BenDLOVA, J. Contribution to the investigation of the effect of cigarette smoking. Sbornik Vedeckych Pract Lekarske Fakulty Karlovy University v Hradci Kralove 14 ('l ): 221-234, 1971., (6) HtaAYAniA, T. Smoking in relation to the death rates of 265;118 men and women in Japan. A report af'5 years'of; followup. Presented at the Amer- ican Cancer Societ+VS 14th Science Writers' aeminar,' Clearwater Beach, Fla., Mar. 27;,1972, 15' pp. (7) Ko.rTUSEa, S. J., DALE, J., Jl&consaN, E. D:, JoHNsoN,,L~ R. biechanisms of' nicotine-induced inhibition of pancreatic secretion, of bicarbonate in thee dbg. Gastroenterology 62'(3) : 425-429, 1972. (8) KoxTUBEx,, S. J., ReDECSr, T., THOR, P., DEmBLNss:r; A., JACOBSOx, E. D: Effects of' nicotine on gastric secretion andi ulcer formation in, cats. Pro• ceedings of the Society for Experimental Biology and Medicine 138(2') : 6~.74-67i, November 1971. (9) Ko:vTUBEK, S. J., SbLOmo.rs T. E., bTCCaEiuH•r, W. G., JoHNsox, L. R., JXCOSSOx, E: D. Effects of nicotine on, gastrointestinal secretions: Gastro- enterology 60(6) : 1098-11Q5; June 1971. (10) ,lio$Ar.Es, A., SILVA, S:, ALCALDE, J., 1V AassBLUTH„ J., Rayos, Jl, BEY, H., SANz;, R, Cigarrillo y secrecion gastrica. I. Analisis de la secreeibnn gastrica en pacientes digestivos fumadores y no fumadores. (Cigarettes and!gastric secretion.,I. Analysis of'gastric secretion in smoking and non- smoking ulcer patients.) Revista Medica de Chile 99(4) : 271-274, April 1971L (11..). MORAI:ES, A., StI:VA'., .S!, OsOEIo, G.,,ALC,I.DF:, J.,WAI6BBLUTH, J..ClgarrllllDysecrecion gastrica., II. Efecto del' cigarrillo sobre Iai secreciSn, g§strdea. (Cigarettes and gastric secretion, II.. Effect of cigarettes on gastric secre- tioni) Rievi'stai Medica de Chil+e99~(4) : 275-279,,April 1971. . 495-0-8' 0-73 ~-12. MC z 8 Q ~ ~'. 1163' t ~ ~ ~ Ul . 0

(12), RosFaT„ A. Potentiation, by nicotine, of duodenal ulcers i'n the rat. Pro- ceedings of the Society for Experimental Biology and Medicine 139(1) : 318--322, January 1972. (13) RoBexT, A., STOZVE; D. E., NezAMis„ J. E1 Possible relationship between smoking and peptic ulcer. Nature 233(5320) : 497-498, Oct. 15, 1971. (14) SxAixH; 1Vi. 1.,, THompsoN, J. M, Ausss, D; Acute and chronic effects of nicotine on rat gastrie secretion. Proceedings of the Western Pharma- cology SocietF' 13: : 178-184„ 1970. (15) SoLobtoN, T. E., JACOSSON, E: D. Cigarette smoking and duodenal-uicer dis-, ease. New England Journal of' Medi:cine 28Fi(2'2) : 1212-1213; June 1„1972!. (16) THomrsoN, J. H., GEoaoE, R., AxauLO; M. Some effects of'nieotine o&gastrie secretion in rats. Proceedings of' the Western Pharmacology Society 14: 173-177, 1971. (1'7) U.S..Pusric HEAnTH SBSSZCE. The Health Consequences of Smoking. A Re- port of the Surgeon General: 1971. U.S. Department of Health, Etlucation, and' Welfare. Washington, DHEW Publication, No.. (HSM) 71.-7513;. 1971, 458 pp. (18)~ ITtS: Pusr,ic~ HEALTH SksvicE. The Health Consequences of Smoking, A Report of the Surgeon Generall: 1972. U.S. Department of Health~ Educa- tion, and Welfare., Washington, DF3EW Publication No, (HSM) 72-6516; 1972; 158 ' pp. 164'.

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