Tobacco Documents Online

bgen qrea~ent igaretteaWd Icnow of no ntiflt evidenue that today's addi- aesinereasethe toxicity of aigarette and tive have uncovered no ei~idence thus far in ongoing t dysea of the'Smoking and Health However, , this remains a' j,~iiity tltat futpre inveBtigations tl6alify. )tHomburger states that only an ~civ8 bioassay of amoke itself, as' ~dded by fiuman smokers, can secriiminate between hazardous and ' Ss har,ar . us cigarettes. We agree. tia ie -Why the Smoking and Health am conducts studies of human iokers on an international basis. ever, it takes 15 or more yeitrs to mulate sufficient applicable data i meaningful analyses. In the mean- ms, we believe that agradualreduc- m in exposure to toxic c~wtituents, ®uggested in our paper, is a reason- approach for the millions of okers who persiaY'm their habit espi.te its 3cho / adverse health Coeta.:._. ._..~.. ~. - do B. Fioa. PrO T~ ".ft : lhpoa.l pntIDrtu m HqM e+~n..a.. Md ob~.J. Lvxq6 PHD ,'-6Mmcairod,M4• ,. amHw., / ~ . ~'m'~k`'' rora a~4/ Tolnm aa c..... t a..wva Nw Yrci..Wde®ic in pp pt~.p ElLatioe 7,7NE87-10y/ !!abik Hu1W wwd tass. ttazerd4us, ~e~l~tor, in a reeefit iasue of x I n1 yt c[, Gio Go~ and I ynCh PhD ~t on ~ lsvels of ejected,. nSai~taents : . . in ,~.,. ~tay1960 cigaretfe:d" at a een@ume an ` ot `isj= mortality , - tl~at of a namoker ~i~levele tranalated num of piresent- ~iaep ? dzarpttRS in ormgtion;to,helg. .-- ouailenm't3ie validity o~ r aouclu- I aiou Here 3:will note ~two such 5s6umptions. '' .. . . . First, the vast majoritqof curren,t. reguiat (eg. pgcic~ake~ fii= bale. ~ienee, for a meaningful com= parison between present-day low tar and nicotine cigarette smokingait$ the pre 1960 ingestion' of ~gmoke con- stituents,. the latteYmust be aapoci= ated with inhalation. Yet, assuming inhalation, as the authors implicitly have -done,se,ems unreasonable. Smokers of'on~'.sr two Cigarettes~per day often Oo not inhale. Many of those who,do soon become regulaz heavier) smokers an~l. henee d~ep dt of the,two-a-day clasa._Consequently, their increased risks also drop out of the data the authors have examined: For a meaningful co{nparison, a necessary (alldfoughnot sufficient) condition is'that the authors study a cohort of smokers who (1) smoked for a long period (preferably lifetime), (2) never d~aviated substantially from -theirtao-a-day habits, and (3) always inhaled.-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 pne-1960 two- Cigsrettes-a-day, smokersiwere never heavier smokers, are the relative health risks of the two groups direct- "ly comparable? The authbrs' implicit assumption is that they are; both scientific evidence and logic suggest otherwise. It is important to note, as Dr Gori observed in a personal communica- tively few such smokers in tb,e gener- tion, that the authors were "address- ai population. However, an ongoing ing the general smoking population, epidemiologic study sponsored by the not'specific subgroups. The effects of National Cancer Institute's Smoking smoking on an individual depend ... and .4-Iealth Program in eight US on several factors." Thus, even if one cities has found that-of 274 two-a-day believed the authors' analysis, it says smokers, 157 (57%) inhale. A similar nothing about the relative risks of study in Western Europe' has thus certain high-risk groups, such as far identified only 47 two-a-day women who are pregnant or taking smokers, but 29 (62%) of them inhale: birth control pills, asbestos workers, Although the sample sizes of these and personp with histories of cardio- studies are small, we believe they .r probleme. _ represent some of the most oomtpre- purpese 3s writing is. not to. he~SSive data aviiiable on t}gs inhala- queatlen the hasic premises that tion praetadsa of t~ro-n d~ s]noierd. underlie the • study-that b'.urther, reslwn~a#stp~atrmoev ainokfng low karniaoCSno ciRa- fapit8eiris u~a}st~lb n '~" Gorl a contztSUmg efforW to and promote less haxardous a materialsandbehaviors A'ndlreeogs nize that throughout hia`v+ark; he-$s cateful to avoid the texm 'safe" ciga-. rettes-and that be and Dr yneh aeknowludgVthfit.,nven the "~tica levels" of smoking "could ptiU.imply , an important risk," alll}ou~h` they. -believe "it may be ,flitficult , to detect." Like the authors, Iregret the lay-media's predictable miaintegpretation of the researdh, which mayAconesiX. '. ably induce potential quitters;-to adopt an alternative smoking behav- ior having deleterious healtbopnse- quences. I also regret that, for Cheir• professlonal audience, the authors failed to qualify theirfindingA ade- quately by emphasizing their critical dependence on highly questionable assumptions. The Gori-Lynch article offers some interesting calculations. - 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.aa.they. counsel their patients onthe conse= quences of cigarette smoking. Kw.[p E. W~. PHO UnHa,iM/ of N4~Ipm--- ' sqwoi ol PuElk iN.IM Mn Arber In Reply.-We appreciate Dr War- ner's perceptive- c9mments oil_-0urrecent article in '1'Its Jooxx,u.. Dr Warner states that it is unreasonable to assume that the majority of` two- a-day smokers inhale. Scientific data on inhalation practicea. two-a-day smokers are sparse, because la- -:i E1 0 ee 'Vao11&_MMn a ^ ~-5~-+?6 e~ ,a... a~•~~ ~ a 8 l3 a 0 edr • N) O ~ rn