Tobacco Documents Online

1427 ' . PAPERS AND ORIGINALS ' Changes of smoking habits aud coughirn mien smoking cigarettes with 30%p1 N~S'hVI, tobacco substiitute. S F'REEDMiAN,, C M FLETCHE'R Bririai Sf.diuurf7ournef,1976, 1,1427-1N10 Summary The etiects of smoking cigarettes with 20'; of the tobacco replaeed'by NS1VYtobaoeo substitute, which lowered''their tar and nicotine: delivery, were studied by eomparistg them with the effects of, conventional cigarettes iit a oontrolled' crossover' trial lasting 20 months. Chest symptoms, cigarette eonsumption, and forced expiratory volume in one second QFEV;) were measured each month. Two-hundred men began the trial and 159 completed it. 79>;etest',cigarettes were acceptable to all but one of,the men. In a subsample of 35 men, estimates of; nicotine intakrwere obtained'from monthly analyses of cigarette' stubs. On changing from NSM to control I cigarettes six of the 14i men, who were accustomed to low nicotine, kept their'nicotine intake downiby'some change in smoking, habit. Before the crossover andithis change in smokingg habit the men smoking'NSM cigarettes had a small but significant reduction of cough. Cigarettes containing 30% NSM and delivering only I, mg of nicotine are likely, to be acceptable to,smokers and' may reduce coughing. Further, trials are neededi to confirm these findings and establisli what long-term effects such cigarettes may have on smokers' health. Introduction Despite th0', conclusive epidemiological and experimental evidence incriminating cigarette smoking an' a main cause of chronic bronchitis with airways obstruction and the'considerable publicity given to this and'to the other dangers of this habib there has been noi appreciable fall in cigarette salts'escept in sociall classes I and 11,1 and, even if improved methods of dissuading people from smoking cigarettes are developed, many. Depnrtmentof MediHne,: Royal Postgraduate Medical School, Hammerssnith.Hospital, London W12 OHS S FREL•D111AT7,. rtm,, atav, leeturer. (present , address: Departmmr of Medicine, Chase Farm Hospital, Enfieltl, Nidtllesex)C. M FLET('.HER;,am„yner; professor ofe6nial epidemiology williprobablycontinue to,indulge in this habit. It is therefore important to develop Icss harmful cigarettes to combat smoking- related diseases, and we welcomed the'op;portunityto soewhether respiratory syntptonss w ventilatory capacity were atiected' in the shoro ternt by cigarivucs containing an artificial non-tobaceo substitute. This SiiSM tobacco substitute was developed by New SmokingNtaterials Ltrl and is madefrom:cellulox. The effect of adtling this ao tobaceo',is to dilute the products of pyrolysis of the tobacco and,thus reduce the amount of nicotine and, to a lesserdt:gree, the tar dcli vered,by each cigarette. We report here acontrolled crossover'trial in which conventional eigarettes wete compared with cigarettes containing 30"; NSM and 70% tobacco. 1Vlethods. MKtti I sA'Mt9.a ~~. The volunteen'for our study were recruited by sending a simple questionnaine,toall.men agqd 25-577 on thelists.of six.lbcal general practitioners. The questionnaire contained' 12 questions about smoking habits, andifromthe.rep4ics we'sulected all.those menavho smoked at least,1q cigarettes a day,,most:of.whom.admined :o some cough. Thesee men weree then visitedd in.their homes by trained ficldworkers . twice over three months in the summer of 1972. At each visitt the fieldworkersadministerad I a detailed questionnaire about smoking habits, respiratory symptoms„and chest :disease; based on rthe MRC questionnaire on resp'uatory, symptoms,t and' measured ventilatory rapaeity,, coughfrequeney, and sputum volume using techniques described below. They, also tried to persuade the men to stop smoking:. Some men had participated i in similir'studies of other cigarettes and had originallybeen recruited inrthesame way. Afterr.the second visit we wrote to over'94°.a, of,the men~(aboun30o) who.had saidd they ~were unwilling or unablb to stop smoking andwhod had,no history of ch'est.diseaseuther.than.bronchitis oremphysemaaskingr them to co-operate!inthe rest of',the.study,:Theyagreed,to.smoke only cigarettes provided by us withoun ctiargefor about onee year. This was'the first oecasion on which!the question of cigarette supplies were raiud: From those who were willing to participate 300 1men were, selected and.matched into.pairs, as described below,.The.men wcre: regularly supplied withicigarettes and were visited every four weeks; fonairepeat of the measurements performed!at the initial'visits. The study continued for'_0raonths. MEASI/REMF.H7SAreachvisit forced expiratory volume in one.second(FFF,)e andi vital capacity (VC) wvc measured using;a porrable:dry sFiromrter , O I`sYJ' t~ . t

1428 BRITISH Msutcet.lot671-.iAt. - 12 JttNg 1976 ' E I The,frequency ofeoughing.(cough'seore); was estimated usinga mtthod described by' Field" based onn a techniquee developedby. . Inghame for quantifyingsymptoms. This's technique.e consistedd of CI'GARE7-tE..COrsvAtPnox (Ganw'I1td).'14treemeasuzemrntssveremadearealyies ""`outo(thetrcighbtiuihood. Only one.ofthem found'the tcst..cigarette' wereall recorded and the maxima subsequentljr . selectediand used. unacceptable. Theresultsaregiven.for.the remaining1G'0.men. devising a series of statements's on' etrughfrequency and amount of pDlbgmsanging,,for cough„ftom "Iidonk',remembercoughing at alll today^'to'9haven'tstopped,coughing all day," and, forphlegm,, from '9~e have not't brought up phlegm since this time yesterday" to. "I have'brought up more than an Iegg-cupful 'of phlegm,since this time yesterday." There were intermediate statemenn, . representing very, sntallgradations:ofdrequencyof,atugh oramount.of phelkrtt. Thesestatements.were.typed in adjacent'.pairson cards and.presentediin random orderto: each subjecq who:was ask'ed'to ~sayy which of the: tsvo: statements'on the card:waselosen to.his.eough during the past day, or h'is:phlegm on each day during thepast week. A..aossover point was recorded when the subjeet'.ch'anged from choosing thehigher'to ohoosingthe lower, of ~thepaired questions and thiss point wms'taken ashisscore. The eough soore provided a srale of 11 points and the phltgtrt scxxeoneof:eight points... aUB1LtMPLETwentymen~fromeaehgroup,wereFicked.outiatrandomandasked to save their eigarettee stubs on thee day before the fieldworkers' monthly visit. The tips were subsequently analysedd for nic:otine content byy theresearchdepartment:of' Imperial Tobacco: Ltdl,The stnokerr doseof'.ni¢otine was calculated from thetipeontent.and a "tip retention factor." TAisw•as based on the.proportion of the.total _nieotine retained by the tip when the cigarettes wxre.smoke& in a , standard way'by a machine. CIGARETTES The control cigarette wasa 7(1-mm long 25:-mmeircumferenecSlter-tippcJ ci&arette. The test cigarette was,a blend of 70"'o,tobaeco: and.30'7o NSM. Prelimitcuy trials had slruwntliat cigarettes containing a~higher'percerttage of li:SNtwere unaeccptablo.to most:smokers: - largely' berruse of .. th_it eatrvmely tine . ash, which wass difficult too control. "flhetestcigarerte,had alrr",,, rs-rlhctKxtiin tar(total parti¢ulate , tautter#ree of water and nicotine) and n 27P;,, reduction in nicotine deliveryeomparedwiih'i the corrtroll cigarette (table 1). Carbon ttronoxide andlacroleindeliveries of the.two cigarettes were identical, but otherr eonstituentsof the vapuur'p,hise, inchwlingg acetic acid and aaetaldelydeq were reduced in ~the tcu ug.trrtc. 1The.eigarettes'were identical in appeamnceand packaging, T;hey weredeliveredito.the.men everytwo-vcks: lach man was initially supplied with.slightly nrorecigarettcs' th.urn his average consumptionn in thepretrial period, and'subscquont deliveries inercased ordkereased , aecording to the previous ciiyarette eonsurnpt ioni t lrr.aim being always'. - to'.supply about three.packetsaformight tnorethan the.number.said I to.have been smokedl,Any unsmokedeigarettes wcrereclaimedlat thce next delivery.. EXPERIMENTAL , DESIGN ~~ AND ~. ANALY515 _ Out of about 300men,who.wereavailuble.forindusionim the trial 200wereseleetedand matehedliitpairs by~a~computerprogramme. Thematching.was on nfie.basisof five initial characteristics: age,, cigarette . consumption,FLV i, cough scwre, and i sputum score:. For eachiof these indiecs', r.vo or three gradeswcre eho'sen; and the matching', wassuch that each pairh.rd the samte graelds ofiall.initial~eharacteritticS. Eachrnembecof a matched,pair was •allucatod at random~to.either the test (group 1).or control (group 2)'.eigarcttcs. After nine months,, inchtding a complete wintrr, thee eigarrttes supplied were ~erossediover, . so that thce men in gaoup1who. had tnxnsmokingn tt-st'cigarettes' smoked kontrol ciparettas nnd!vueevcrsa. "Ilhe :men were then told lonly that'.tticy might noti.e sorne differenns in the.eigarettes whieh wcrec to.bc suppliea. 'I'he ezperiment continued for a further.12 months in thee.hope thacsignihcant.ditferenoes in cough score.might reappean We are concerned hcre mainly with resulis obtained at the 2nd'to 8thand. 111th.to.l7th surveys:. Rcsults During the trial~~41'men (20from gmup~.1, 21 from group~.2)ilapsed from~the trial for~various~reasons,,most of them~because.they,moved The men ~ were heavy~ smokers. Before the trial they smoked an average ofi33'cigarettes a ~day. Those in group I averaged one cigarette a: dayy more than those in group 2. In spite of.the fact that,alf rnen were receivingfreeg eigarettes„ average consumption remained almost't constant throughout'the,trial and.vvas no greater than thatrobserved' beforrfree cigarettes were issued (fig 1). There~were temporary small'~ increases.each Januuyattributabk to slightly heavier smoking over the preceding Christmas holiday. There was little difference in the average,:consumption of the two ei);arettes'in the fiks[ ~ 15 months, but in the last'.fuve months thcre: was a small but insigniRcant'.incrrrset in consumption of the test cigarettes. 3B i ' 0 MS14 otqnntttrs 11/' • Control eiqorettes & Pictrtullvalucs. t ••••• Group.I - Group 2 O Jonuort197b ' July laauart 1974 , lul7nu l+-Meaa monthlycigarcue,oonsumption of.'men in.groups I and.2'hforeandiduringstudy. . . ACCI:II'rAHILITY OF'lQSM CIGARETirFS'~. ~ The pretrial smoking habits hadi beem recorded at thee initial interview and.analysis.oftltese data,from'30 men, chosen at random, showed'that'.they had smoked an average of 34-3'cigarettes'per dayy with.average tar andlnicotineyieldtof 194 and;1-40'.mg respectively pereis:arette (caleulated from the tar and'.nicotine table issued by'the Department of Healthand Social Security). Theseyiehissveresimilar-to thosec of the eontroJcigarette (table 1): There were no significant di[ferences:between the ty,pess of eigarettepreviou.sly smoked by men in,group.t.and.those.smoked by men in group:21 A't,thetimeofthet crossovere no: onee complained or even ~ commented on, thee change. AA questionnaireac'the enatiof.the trial, returned by1511~of.the 175 menavailable,n showed that 649 ; , of men on N}SW and 1561" J; on controll eiguretteshad occasionally, smoked otherr brands . off cigarettes . during .. the trial. Scventy.pereent ofitbesemenionl*ISMcigaretres and 7P'a on control cigarettes had preferred the trial cigarettes toother cigarettes. A more detailed study was tnadeof the elfects:oflsmoking the test and control,cigarettes on mean eigarette eonsumption.and estimated nicotine intake in , 35: oGthe 40 imen' who were:asked to: save their: stubs for analysis each mosrth and did so before and after the.crossoveroften enough for reliab!ee analysis. Reliable . results were available only for thesevenmonthsbeforc and for thk3rd and 10th~months.aftertheerossover: Mcniit group.2'in this sample, who star2cd':with the control eigarette, obtainedan average oC1-4lmg,nicotine par, cigarette bcforethecrossovec, and when thcy,changed to.the.hdSAt cigarettes thcirnieotineintakefill.eommensuratelyand.uniformly.to an average of'. 7AStt t-A4erurr yirUrer eirarrrrr rehctt muchinr-mnker! (Jn nrf /r uff vofnme), 6.ticalatt m]tter, Nicoune Ifreens.are.arms~'Carbon~monua:de tmg): ` ni<~)e~ _I,, tv;s) NsXtirie,ren- .. ~ bot ; 1664 cumuol cis-rsrtn .. 1-39 . 19+aY ^pry ur.^ 4'.7• ~. 4'7",.

etI1f16H MEDICAL'IOURYAL 12JUECE 1976 '. ~ rABlt'st-tfrax aim+fint inlale„Ligartlreeoaruonpriwr, :JtimatnJtar inrakl,aad,ranjksterrinisxb.wnrplrr.oJwrnbefwe'arxfafiertrosruu~r,. :3ioptine int.ke,cig.reue (mg). 4.: .C3t+mette., das" ~ \imtime inr.ke day tdqt) Fsti inated• tar intake day (ma) . . - Jifeanvrugh+core I'. t Befwe «osanver After -er c ~. Cipnenel Sampk Sdmpk, ., group Vatucs., group~. Values \SiN 1 103 Itla {~. CnntruL I 2 140 1-12 NS.N 1 r 325 31;6 Con ud I I~. ~ NS:~s 2 1 318 : 339 ! 7Pt1 341 Gnuo/ 2 us : 367 NS:N 1' 552 i 573 Cunrru/ 2~ 636 I ji 524 NSM 1I 422 2, 4 -81' { Control 2~~ Su!6 . 11 4.00 •Eaimatederiredifrao (niepine inuke nicoti-yield) aa tar ddtik•erya: ciprertn • per Jay. I-08 img pervigarette',(table,1l and fig 2). Thase',twointakes were close m'~ those expected from, the', nicotine delivery of~ the two~o cigarettes (l•39'~and 1-01 mg) measured byy a~.smoking'.maohine and~suggest that these men' made no change ~in the way, they smoked theit cigarettes. Simoe',their~.cigarette consumption remained ronstany.they.ap,pear.to~i h'ave accepted withoutdemur~a~eonsiderable decline~.in their dailyy nicotine intake. Tlu~~ men in group~.1 ~ behaved'~.in ~a similar fashion'in~ ehanging'.jront ~the cigarettes they, hadd previously'smoked, with a mean~ nicotine delivery of'..1i4~.mg',per~cigarettesy,to~.th'e NS1VS~~cigarenes,. diopping!their meannicotinrinraketo d'0a.mg (il<06'mg excluding~two men who had~.exceptionally~low~~intakes):~.When~they.ch'anged~to the wntrol'~cigarettes~~.1I kep,t~to~,theirprevious'~.smoking habits and thus~~s increased their mean intake to.1h35 mg~percigarette: The~.other six~~ men~dropped their mean intake~.to~.0i9'mg. Theoverall mean'intake~~ of the men~ in group 1.I sample while they were smoking :the control ~' ~ cigarettes was ~,thus ~~.kept ~, down to only ~ 1-12Img. (or 1~• 18 mg excluding the two memwith exoeptionally low nieotine~.intakes). Since the~ - measured dclivery~of'.the cigarettes war~a•39'~mg~and thc.men did not~~t change their average.number of~, eig•arettes~a day,,about'.one-third,of't them,,acetrstorned to a low nieotine'.intake for nine months;~kept'their ~ intake.down on changing to eigarettes'~ with a~ higher nicotine delivery_. 'I'his must have been ~~done ~by some change in~theirsmoking',hahits- ~ for example, by taking fewer puffs drom each cigarette to leave a dmnger ~~ . stub ~or'takingshonerr putfs. I 74ris change in smoking~.habitsg must atso hevc',redueed the extx+cted.d inoreasc.of tar intake on changing~,to the.contro6 cigarettes. These~ intakes may~~be estimated from theratio.bertwecwthc intake au&the~ delivery~of nicotineinthe~.two halves af the trial (socctable tll)~.and indicvte shat men imgroup 2 may well have had a higher daily intakr.of tar by,about15". .in~the first half~~and 9';,u in the~second hatf'of.the study. SY'Mp7oMSDuring the first halfof.the srudya significanrdi(Tcrence.wasfound in cough score from the third Imonth otltlle trial till the month before the crossover (fig 3). Thereafter there were'.no signifrcant ditferences in the.eoughseoresbetween the.tsvo groups. There'as an expected seastuwl'.increase in cough scures in the first winter of the experiment, which~had. been observed in a similar srudy,' hut thisnvasabsent in the second winter„after, the'crossover, Notigniflcant di}ferencerwere found.between,monthly ralr,esof groupl and.g,roup 2 men either in matched p,airs.orin 211 meninsputuns score, frequency of chest ill- nesses, F1;V;, VC, orFL•ViVC. Discussion andlconclusions Two mai:i findings from oursurvey are of practical interest. Firstly,,.eigYrcttcs made of 30°n.11':SA1 and.70°„ tohaccow'creaeceptable to all hut one of thc 200 men i iiarlinntrials of cigarettes , containing 45",.;, or more of NSVl'shocvodlthaothey were much less aeceptablc,,largely becausc;ufltheir,fragile ash. The free issue of~cigarettes'.docsnut sccnt'to have affected their aceeptancee muehi for cigarette consumption did not increase during 2h'e trial. Secondly, changing to cigarettes with a 30";, lower nicotine yield at the beginning ofthc trial and at the crossover resulted in no suhjectivrcompl9int or apparent change in smoking habits• 1429 Groupldt7men) I .. r+. : ~~io.p 211Eanenl NSM Conreol: Co trolNSM 06j i Crouo.er r o~NS'M-qprettes ~~ ••^• Group,t! •~Control-eiqorettes -~ Group 2~~ ..Pretrfol:ralves Jonuory1973. July Jnnuor,7197, Julry, rto 3-Ataan munthly cough scoresof man in groups I and 2.during study. aSignihcant'.diRorenccs in cough scorr.(P<0-0n). Our findings are different from those of previous reports of short-term trials in which greater changes inmieatine yield did affect smokers' habits in ways which increased their nicotine intakea-r Only one longer-term study has' been i published." Guillerm et aJ'pe.rsuaded.75'peoplewithan averagesmoking~historyof3(f pack-years toswiteh~ front cigarettesyielding. 1r7mg~ of nicotine to othcrs yielding Q-7 mg. "Seventy-thrce of their subjects were'.ablb to'.kecp this-up forfive w•eeksand; althoughaltnost half of them increased their,cigarette consumption„xhe average change was only from 32 to 34 cigarettes aday: \`Ohcn our men changed from control to test cigarettes with nicotine yiclds of 1139'and 1-01 mg respectively theirnicotine intake, as measured by, stubb analysis,, dropped proportionately. This analysis measures only' nicotine drawn through the stub and the men might have kept upp theirnicotine intake'.by deeperinhalation of the same amount of smoko drawn through the filtcroCthe lowcr nicotine cigarettos, bur this would require a complex change of smoking habit, which is not very tikely, It isremarkablcthzt when ~ the 17 men who had I been smoking,thc lower nicotine NSM cigarettes stvitched back tu,thrhigher nicotine'cigarettes six of tliem seemod'toihavrchanged Itheirsmoking,hahits so that they kept their.intake.of nicotinedow•n.to the.lower levets'to which thcy,had become accustomed.'llhese findings indicate that many smokers, woulfl'bc quite content with cigarettes yielding only I mg of nicotine. \Crc eonsidbr'that a study,un cigarettes supplied frce is relevant rl0'.2-F.stimitednieutinc intake of'subsample.of inen fromgruups 1 land ~2 ahil¢ smukiirg.l7Ss\t andd conuoL cigarcnes.

., to smoking habits of the generalipopulationfor although this could have encouraged accep[ance,of NSM cigarettes at the beginning:ol the study it could not have been responsible for thrabsence of any awareness of the change of cigarettes at the aossover. 'I'he uide range of'estimated nicotine deliveries cralculatedl from stub analyses (fig'2) indicates that indicidual,intakes of nicotine and other substances in cigarette smoke cannot be safely deduced from measurements of their yields when the cigarettes are smoked in a standard'wayby machines. Methods . for accurate quantification of individual smoking habits without affecting them, are essential in further studies of this kind. Measurements of carboxyhaemoglobin might prove valuable for this purpose. The reduction of' cough score of the men smoking NSNL cigarettes before the crossover was temporary and small. The largesrdifference was between a score of 4'and'5,,which repre- sented!roughly the difference between "I can only remember coughing a couple of,timcs today" and "I have coughed a few times' today." A larger difference might perhaps have been, observed if the average'score had'been higher. The lack ofany divergences of score after the crossovecmay, have been due,to the small difference in estimated itar-and presumablyof compounds of the smoke that cause cough-between the'two groups (see table, I1). That spiromerrio tcsts showed no difference is not surprising since there is now evidence that about seven years arc required to establish rates of change of these values with sutfyciont confidence to distinguish even between smokers and non-smokers; ' and I it has been reported that the immediate increase of airways resistance on smoking,NSM or conventionul' cigarettes is simil3r:!'' Our'main.conclusions are: firstly, since cigarettes containing. 30";,,b7SWi were acceptable.to 199 out of 200 heavy cigarette smokers, it is reasonable to suppose such cigarettes are likely, to be generallj' acceptable and those who smoke them may benefit atJeast by some decrease in cough; secondly, cigarettes with a nicotine dolivery of'no more than 1-0 mg,are also likely to be widely acceptable andlsmokcrs who chnnge to,this lower level from cigarettes delivering neariy, 1•4 ntg are unlikcly'to have'anye increased exposure to tobacco smoke, as prcvious studies have suggestedie-• Furthermore, since uu the reverse change some men changed their smoking habits tu .l vwid a significant'intrease of nicotine intake, many smokers mii;ht in,tituc become aecus- tomed to an evenlowery,ield of nicotine. eRtVsH ntEolcnt. JouRHAt. 12 Jtr.as 1976 These conclusionsarc based on small samples but are unlikely to be grossly misleading. If correct they are important, for 79 ouoof 109 brandsJisted by the Departmentof Health and Social! Security in their tar and nicotine tables in February 1976 delivered more than 1°0 mg nicotine and, w•ith ii; a larger dose of'tar than most cigarettes delivering,less'nicotine. According to our'findingsi many smokers would be quite'content and might suffcrless harm to their health than at present if'strc~nger'brands of cigarettes were',notavailable. Inclusion of'I+:SMi in cigarettes night makc',it easier for the manufacturers to reduce the tar and nicotine. Further studies of'this question are undoubtedly necessary, for'our'results are basod!onsmokers who were nora random sample,of any defined population, langer,trials lasting foras much as five to 10 years would be,needed to assess the elfects of: smoking such cigarettes on lung function or mortality rates from smoking-related diseases. Our tindings show bo.v important it is that in such studies careful lassessments should be madeot any changes in smoking habits that may follow changes in the types ofleigarettes smokedl We would like'c to thank New ~ Smoking~ Materials Ltdd for ~ their~ support and, in partieular~. Dr David Conning andM'r J I V~G regg ~,fur~r help with the~analysis:~lWe.are grateful to Mr Michael Healy~of, the Clinieal Research Centre at'~NorthwickPark J iospiial for the statiitical . design of~the study, We~would alsodike~.to~afiank.Mrs~~M S'tuart,,Mrs~ M Asher-Rclf, and Mrs Maryitieyfus~for~all the helb~they~gave in~ running~theitudy., . . , References I7bddt, G F,,Chanper in Svroking Parttr.ru in the.UK. London„TobaceoRescareh Council, 1975. a l.te+Gca Rcsea ch. t:ouncihs . Committee on Researeh into. Chronic Itronchitis: Q,nrraionnoircon Rl.piratory.rympromrand fn,rrvrtionr/or its Urr. London, btRC, 1966: ° Fiadd, G S, InrrrnarionalJoornaf oF'Fpidemiolcgy,, 1974, 1;,135.. t ingh:nn, J.G, 8•itith)ournal~ofSociaf ondlC(inira! PryrlulogY„1965, 4,.131. - Froedman, S, Iilcteha; C M, and Field, , GB, ]au.nalof tha. IJarional Ca«rlntlitar 1972,48,1505 Iy.i • Ashr tf,and lC'atson, D K R eirhMrd cat)ov.nol„1970„3, 679:j. r Ruasoll, M A H, tral' BN+i hAfed cn!)o a!; 1973. 4„5'.12 /. • Frithi CID, PiyrhophannacuforrS, 1971„19„1P_B_ _~. f- RGuiBerm~,R,,rt,al,LrrBronder,1974;24,,2111 " ' t~ Fletuher, C, enal, 7Vu.A"anna! Hirroy,of Chronic Brenchiti, and Emphyrema:. L.,maton, Oxfurd Universiiy.Frcns, 1976. - Is CostatW,,J. F, tr ol, Lanctt, 1975,,2, 678:, Low-tar medium-nicotine cigarettes: a new approach to safer smoking M A Ii RUSSELL Biitish6trJica77uurnu1,,1976„1,.1 13o-t1n3 , reductiom of tar intake is limited.d by the reluctance of smokers to.tolerate similar reductions in nieotine: A new approach wouldl be to aim at lowering tar yields of cigarettes fTom the present average of IS mg to around . 6 mg but maintaining nicotine yields at around 1-0~to.1•2 mg, which would be acceptable to most smokers. This approach requires thatt emphasiss bee placed on tar: nicotine ratios as well as on the absolute yields. These ratios for'brands on sale In Britain today average 14-2 and'range from 9-6 to 20-8. They provide an additional' guide'for comparing,the relative harmfulness of different brands. For example, 35"„ of cigarette smokers i n,6trltain Addictiomfbesotch'Unit-,tnstituteotl'syohiatry,SyaudsyeyHuspital„ smoke.either L"mbassy.Filteror.Players 11Fo~6.Filteri,by' t.ondon SES. M' AH'RCSSELL. NRCf•, changing, to. John I'lay,rr Canlton King Si2ee theyoould NRCI'6yCtt,,srniorIc+rturer and honoraryredueetheirtar,intakeby.more.thaa20"o,withouthavingy conaultant psychiatrist Summary' The logic of expectiny; people.vhn caunotstop'.smoking to switch too cirarettesthat have hardly anynicotiney is questionable. Tar and niootine yields of cigarettesavailnble in ~ Britain today correlate 0-93, and further to suffer any nicotine deprivation.