Tobacco Documents Online

.eY .:,.r;. :.. t~ , .4 Sociaily Tolerable Cigarette Smoke? To the Editor.-The Wio1l Street Jour-nat'(Nov 1, 1978, p 18) suggests that "because of news aocounts of a' study 4 by Gio B. Gmrf... much of the public A - [was left] with the impression that some cigarettes are'relatively safe to smoke in limited quantity." The arti- cle reports that because of' this, "Smok'ers of extremely low-tar ciga- rettes, who ~ were once largely igllored by' the industry, are the targets of' intensifying market competition." This calls for a' close look at the arti- cle by Gori and Lynch ('240:1255, 1978), who conclude that smokers who would' not exceed certain levels of intake of tar, nicotine, carbon monox- ide, nitrogen oxides, hy,drogen cy a- nide, and acrolein would subject themselves to a risk which could be considered "socially tolerable."' Before 1960; smoking two cigarettes per day exposed the smoker to amounts of the aforementioned sub- stances, which were tolerated without demonstrable epidemiologic effiect: G'oril and Lynch calculated the num- ber of today's cigarettes that could expose the smoker to similar amounts of these same substances. Such num- bers of modern cigarette& were assumed to be' permissible without adverse health effects. This was corrected for the low nicotine content of some contemporary cigarettes, which could lead to the smoking of a greater number of cigarettes by those smokers who unconsciously titrate their smoke intake. ,_ . Such, extrapolation from pre-1960 cigarette smoke to today's smoke of low tar and low nicotine cigarettes would only be justi'6ed if the composi- tion of the diltited' smoke remained basicallyy the same. However, the complex manipulations necessary to obtain lower yields of the six sub- stances studied' by Gori and Lynch alter the' proportions of other smoke ingredients and thereby may well change' the biologic activity of the smoke, not to mention the possible introduction of new smoke compo- nents that may conceivably result from addition of' new flavoring agents or other new tarbacco, additives or ingredients that are not regulated in the United St.atess Only a valid and' practical in vivo bioassay of smoke itself, as it is inhaled by human smokers, can discriminate between hazardous and less hazardous smoke:. Bernfeld et al' described the induc- tion of leryngeall cancer in 20% of carcinogen-susceptible inbred Syrian hamsters exposed to cigarette smoke, an incidence twice as high as~ previ- ously reported by German workers in randomly bred Syrian hamsters, but too low, for comparison of' different cigarettes. More intensive exposure' caused laryngeali cancer in 47% ' of smoking animals. With smoke dilu- tion, laryngeal cancer incidence 2142' JAMA. May 19,, 1979+-Vul 241~ No. 20 dropped' in a dose-related fashion. Cigarettes made of a cellulose-based tobacco supplement, causedl no can- eers. Various proportions of this m'aterial' mixed with tobacco reduced smoke carcinogenesis. The cancer-causing potency of'vari- ous cigarettes can thus be measured, and' commercially available smoking products must be b'sologically evalia- ated before conclusions are drawn on theirrelatfive hazards. Only such smoke inhalation studies could estab- lish whether the carcinogenic effects of'smoke have indeed been reduced, as impliedl by Gori' and Lynch. P. r+ou««,oe.. 110 - e1p,Rqeeran MaUWU Gmsndm.. wea 1:Bernfeld P...HomburIIerF: Ruasfiela.AB,strai. ditferenees in the response of'inbred IS)ran hamsnre,to eiqaretta smoke inhal.ation.. J. Natl Casxer hut!S&s7_K 1974. iBernfeld P. Hcmburger P C;Qarette.smoke iehasr• tii.nstudies'fniinhred.3vrian hamstert 1. Methods and dosimetry:. Tuaieoi,App1Pltara.eeat 45:784,1Y$In Reply.-The first issue raised, by Dr Homburger on our recent article . in Txe JouttNat, is the possible altera- tion in the proportion of toxic smoke constituents of today's cigarettes compared with pre-1960 cigarettes. The formulation of today's low tar and, low nicotine cigarettes is carried out by processes that reduce quanti- tatively, and largely nonselectively, the amount of smoke produced' in both the particulate phase (which contains tar, nicotine, and water) and the gas phase (which contains the other smoke constituents). Table 3'of' our article suggests this overall quan- titative reduction, in that the sixx constituents addressed'l are reduced for each ofthe'cigarette brands listed. The constituents considered were cho- sen because these have been impli- cated in human d'isease'incidence. These and other constituents have D; been addressed by the National Can- O, cer Institute's Smoking and Health CA Program, where over 130 types of' Q experimental cigarettes have been ~ tested forpotentiall~+ lower toxicity. Results to date confirm that today's ~ cigarette processing reduces known toxic constituents quantitatively. ~ There is no scientific evidence that (~ the reduction, of these constituents is accompanied by an increase in other suspected!toxic constituents. Further- more, there is evidence that today's cigarettes produce not only lower quantities of' toxic constituents, butt less active ones as well. For example, on a grarn-to-gram' basis, the tar of certain present-day cigarettes is less :' tumorigenic than pre-1960 tar.' The reader is referred to chapter 14 of the 1979 Surgeon General's Report on

Smoking and Health for a detailed description ~ of ' cigarette smoke" Dr Homburger also raises the issue of flavor additives, some of which he ' suggests may not have been present in pre-1960 cigarettes. We know, of no scientific evid'ence that today's addi- tives increase the t'oxicityof'cigarette smoke, and' we have uncovered' no such evidence thus far in, ongoing analyses of the Smoking and! Health Program. However, this remains a possibility that future investigations may qualify. Dr Homburger states that only an in, vivo bioassayy of smoke itself, as inhaled by human smokers, can diseriminate between hazardous and less hazardous eigarettes. We agree. This is why the Smoking and Health Program conducts studies of human smokers on, an international basis.. However, it takes 15 or more years to accumulate sufficient applicabie data for meaningful anallyses. In the mean- time, we believe that a gradual reduc- tion in, exposure to toxic constituents, as suggestedlin our paper, is a reason- able approach for the millions of smokers who persist in, their habit despitp its known adverse health effects. aao e. cw.. a,a li,eNe Maamh's.a.o. I . . . Na1qM1 MflautH o11W1Mn {anNSAc ,11A I Co.raius J. Ls.o-. VR.O (ro/ro ConYOl..h10. _... ' - -... . . /leeav,w. Md L Hoffmann D: Sehmrltz,4 Hecht SS. et aL• To6aeco . nrainoRaneaia, ieGeldioa iHV, Ti 0 PtD (eder. Po(yeydae' Npdtcearbonu a.d Caweer. L• Eaoiro+.e+t, CAa,.utry *, po lYaebotisse. ha- Yort; Ae.damie Pn.n,' 1M pp i sius: L S.roiY.p ar1', hldalrk d ReOD" of' Gr SYryeos' F i`G.aral. , public.tion 1979 281-109/5618. Public Hnlth ` s...;n.,m. challenge the validity of their conclu- sion. Here I' will note only two such assumptions. First, the vast majority of current regular (eg, pack-a-day) smokers in- hale. Hence, for a' meaningful com- parison between present-day low tar and nicotine cigarette smoking' and the pre-1960 ingestiarn of smoke con- stituents, the latter must be associ- ated with inhalation. Yet, assuming inhalation, as the authors implicitly have done, seems unreasonable. Smokers of one or two cigarettes per day, often, do not inhale. Many off those who do soon become regular (ie, heavier) smokers and hence drop out of' the two-a-day class. Consequently, their increased risks also drop out of the data the authors have examinedi For a meaningful comparison, a necessary (although not sufficient) ; condition is that the authors study a cohort of smokers who (1) smoked for a long,period'(preferably lifetime), (2) never deviated substantially from I their two-a-day habits, and (3) always izlhaledi From correspondence with the authors, I' know that they have not met this necessary condition. The second problem also relates to' smoking histories. Many current low tar and nicotine cigarette smokers have switched' from lengthy histories of high tar and nicotine cigarette' smoking. If many of the pre-1960 two- cigarettes-a-day smokers were never heavier smokers; are the relativee health risks ofithe two groupsAirect- ly comparable? The authors' implicit assumption is that they are; bbth, scientific evidence and, logic suggest otherwise. It is important to note, as Dr Gori observed in a personal communica- tion, that the authors were "address- ing the general smoking population, not specific subgroups. The effects of smoking, on an individual depend ... on several factors " Thus, even if one believed the authors' analysis, it says Gori's continuing efforts to develop and' promote less hazardous smoking materials and behaviors. And I recog- nize that throughout his work, he is careful'i to'avoid the term "safe" ciga-' rettes and that he and Dr Lynchh acknowledge that even the "critical' levels" of'smoking, "could still1i!mply an important risk,"' although they believe "it may be difficult to detect."' Like the authors, I regret the Iay' media's predictable misinterpretation of the research, which may conceiv- ably induce potential quitters to adopt an alternative smoking behav- ior having deleterious healt'h, conse- quences. I also regret that, for their professional audience, the authors failed to qualifyy their findings ade- quately by emphasizing their critical dependence on highly questionable assumptions. The Gori-Lynch article offers some interesting calcula'tions, But it does not provide any' scientifi- cally meaningful evidence that cer- tain present-day smoking behaviors will' result in statistically nondetect- able health, risks. I hope that physi- cians will keep this in mind as they counsel their patients on the conse- quences of cigarette smoking. -_ Kn..rn E: w..r.: P+ounn.ron ut W4nw.n selwol of Vuane:W.nn AM ArDat ln Reply.-We appreciate Dr War= ner's perceptive comments on our recent article in 'IHE Jourtt.*1A[.. Dr Warner states that it is unreasonable to~ assume that' the majority of two- a-day smokers inhale. Scientific data on itlhalationi practices of two-a-dayy smokers are sparse, because of rela, tively few' such smokers in the gener- al population. However, an ongoing epidemiologic study sponsored! by the National Cancer Institute's Smoking and , Health Program in eight US ci'ties"has found'that of 2741two-a-day smokers, 157 (577r) inhale. A' similar study in, Western D'urope' has thus far identified only 47 two-a-day smokers, but 29 (62%) of them inhale. Although the sample sizes of these studies are small, we believe they represent some of the most compre- hensive data available on the inhala- 1*n :practices of two-a-day smokers. ~Yqrt#er, respondents to tobacco ques- 3~in~lres frequently understate'. eir tobacco consumption practices„ so the actual percentage of'iinhalers is. likely to be larger than the aforemen- tioned values. We believe these data supparrt' our assumption that the majority of two-a-day smokers in- hale. Toward Less Hazardous ClgareRtes To the Editor.-In a recent issue of' THE Jou~x.*rA4 GIo Gori, PhD'; and Cornelius Lynch, PhD, report on "[c]ritical levels of selected cigarette' smoke constituents ... expressed in terms of' pre-1960 cigarettes that a smoker may consume without' in- creasing his mortality risk substan- tially above that of a nonsmoker." These critical levels are tr'anslatedl. into equivalent numbers of present day low tar and nicotine cigarettes ln I order to provide information to help "the smoker to wean himself to.~', progressi vely less hazardous ciga- rettes." While the authors' motivation is bey,ond' reproach, their analysis is predicated on some highly' question- a!ble assumptions that, if' wrong, JA'MA. May 18. 1979-VoI 241, No. 20 nothing about the relative risks, of' certain high-risk groups, such as women who are pregnant or taking j birth control pills, asbestos workers, I and persons with histories of'cardia vascular problems. - - My .puq)ose i~l ;,rsrsitjpg is1 pqt, ~'. _ questiot tha: Yl'aslci kesnzse.-P, that,, 'und'eiiie Ae'authors' study,-tba;' -sntak.i''ng[ tn~ t;ar~sn~?~'cn~e~~'4 'gw' retti~es is pro~ablj*-l+L~•'K~ardoes `Go' health thanvrpey<cigth~ sa tm num- ber of highei ta!td and nica',in~ ciga- rettes and that encouraging the former may be the most effective health-enhancing strategy for a cer= taim group ~ of' smokers. I applaud Dr.