Tobacco Documents Online

I .r 0% Effects of Srnoking, 1Nloditied' Cigarettes on Respiratory Symptoms~ and Ventiliato,ry Caipacity'-1 ' S. Freedrnan, Pb.D., M.R.CP., C. M: Fletcfier, CBE, F.R.C:P. ond G: B. Field,s Department of'Medicine, RbyaJlPostgraduate Medical Scliool; HamrnenmithHrsspitol, London, England IT IS' well established that cigarette smoking is the primary factor in the pathogenesis of'disabling chronic bronchitis. Despite the large amount of recent publicity about this and! other dangers to health which arise from cigarette smoking, most cigarette smokers, even, those with symptoms of bronchitis, continue to smoke., _ _ . We were therefore interested to see if we could detect any difference in the symptoms of bronchitis in a group of men who changed to smoking, modi- fied' cigarettes. We have been conducting a study on this quest2on~ for the past 22 months. The men were recruited from lists of 6 general practitioners in the London Borough of Hammer- smith. Short questionnaires: about smoking, habits, cough, and expectoration were sent to 6f000 men. Of these, about 600, men fulfilled the following criteria for inclusion in the trial: 1') age 25'-34 yeats;, 2), smokers of at least 10 cigarettes per day; and 3) a persistent cough and expectoration as dtfined by affirmative answers to question 10 in the Medical Research Council's questionnaire on. <. respiratory symptoms. Men with a, history of chest disease other than bronchitis were excluded~ as were those with other conditions which might have affectedl the results. Over 300 of these men who said they were willing to cooperate in! the study were visited by trained field workers twice danring the summer of 11969: On these: visits, the: field workers administered a detailed questionnaire about smoking habits, respiratory symptoms, and' other illnesses. They also measured one second forced expiratory volume (F.E:V.t) and vital capacity (V'.C.), using a portable dry spirometer, collectedl & sputum specimen (the subject having previously been ptovided with a container in which he ~ was ~ asked to collect all the sputum he: coughed up in the first hour of the day), and measuredi cough fre- quency by a technique described below. On each visit, the field worker tried to persuade the man to stop smoking; 45 ' men did so. Those of the remaining men who indicated their willingness to continue being visitedl regularly by the field workers were then asked to smoke ex- dusively cigarettes~ provided by us for a miniinum, of a year. This was the first occasion on which cigarette supply was mentioned. Tlie.men were placed into 75 groups of 3 each. Each group consisted of individuals closely matched for age, cigarette consumption, cough frequency, andi F.E'.V.t. Each, member of a group was ran- domly allocated to I of 3 test cigarettes. The cigarettes were specially manufactured and were identical in appearance and in packaging. They were designed to, provide a standard nicotine content with varying amounrcs of tar and of con- stituents of vapor phase. The clgairettes were designated "A," "B,11 and °`C:" All delivered about 1.65 mg nicotine. "A" delivered about 22 mg "tar'° and "B" and "C" about 17 mg. In addition,, "°C"' had approxi4. mately a 50% reduction in the vapor-phase con. t Presented' at a woricshwp of the Second World Con- ference on Smoking and Health+ sponsored by the United Kingdom Heasth Education Council, held in Londbn,. September24-24, 1971. = Supporned by the Tobacco Research Council. = Prsssnt addresa: Prince Henry Hospital, Little Bay., New South Wales, 2036; ,Australia. 1805 A r7•-t : ..

MEEDMLAN,, FLETGFIEA, AMID F1ELD order. For each card, he was' asked to indicate which statement was closest to his own experience on that day. The answers were marked in on a proforma. The number of'the card on which the answers changed from the more severe to the less severe statement indicated the "cough score" (text-fig. 2). The cards were presented' twice, and ':~' the results accepted! only ' if the answers were ° consistent. Each man was asked to collect the butts of all ~ the cigarettes he had smoied' in 24 hours in a box specially provided. These butts .were analyzed aR the 'T1obacco Itesearch' Council's laboratories to estimate nicotine dose. Of the original 225 men, 30 dropped out for ::, various reasons: 2 died, 3 were told to stop smoking by their doctors, 5 failed to cooperate, and! 20 moved away. Of the 45 lex-smokers; all but 12 started ..,„a smoking again wirchin 3 months, and we have therefore not included any data from this group in, the results. Consumption of cigarette "C" 1~. ~ T~. CYI ~~. WRT ADmOa'..ODOKKIp A, ODQlfi ot ~~ TDR!'.20G47 .6 I~~.. CLI ~. oA1LI~ tLlDan '.000®q Otl= 20Mt , ~wM FwO~~M 1l! 2 t 1 2 7 {I {' ) • • t 1 1 112 2 ! f<' DA'TA CODE SMEET' . stituents that were measured, as compared with the other 2. The trial began in November 1'9169 and ended in September 197'1i. Every month since the trial began, each subject has been visited' by a field worker'wlto administers a questionnaire and' makes the same measurements as on the pre-trial visits. Cough frequency was measured with a special -m form of questionnaire (text -fiig. 1) based on a technique devised by Dr. J. G: Inghazn of the Medical Research CouEicil; Fneumoconiosis' R'e+ search Unit. The questionnaire was placed on 1'1 cards. Each card contained 2 statements about the frequency ofcoughing: One of these statements indicated a greater fixqueney than the other. The statements indicated a progressiwely greater frequency of cough from cardil to card 11„ and on each card the more severe' statement was alternately labeled 1 or 2. The subject was first presented wit;h, card' 3', 6, or 7 and'then with all the other cards ira tandom. OW.y r~r Q Ta~cr-rteuRz 2.-A completad cough fre+ queney prolbrma. Co„y, fma..,,y tl II 21 2 a f. I ~I 2 ! I o toi ~~tt _' I t ? 1 2, IX'I }CI X1 IX IXi J6 X~.IXI X'X~ x~ 1' t 2~ n [ 2T Dat. i 2' / JOtl¢LUAL OF THE YATIONAL CANCER LYSTPPUTE

EFFECTS OF' SMO1=G increasedi sharply at the start but then leveled off (text-fig. 3). Consumption did not change in' the , other 2' groups. Of course, this does ~ not neces- sarily indicate the dose to the smoker of various constituents for, although the original composition of'the cigarettes was known and we could measure nicotine concentration in' samples of butts each month, wewere unable to:quantify any differences or changes in the way in which the cigarettes were smoked, (text-fi'g: 4). , We could, however, make some sort of estimate. : of'dose of nicotine to eachiman, and t,tiere were wide ;'differences between individuals smoking the same cigarette. Cough frequency varie& markedly with the seasons (text-fig. 5). The average scores were N 0 J a01 r M A M J J~ A~ •~. O~. N~ 0'~ J~. I M~ A' Mi J~. JI A N70 HA VOL. 48, NO. 6, JLPNE 19n JYOD[FMD' QGARE1TE5 1807 higher in' the wiiater than in the summer and were higher in the winter of'1969-70 than in the excep- tionally mild'winter of I97U-71. This supports the validity of'the technique. After about 4 months, men smoki'ng cigarette. "C" began to, have lower average cough frequency scores than the others, and on several individiaall months their scores were significantly lower. These differences were clearer if the results were displa}•ed' as deviations from the mean value (text- fig. 6). An analysis of variance of the mean scores for each man throughout the trial indicated that this~ dili'rnsnce, was significant; this significance became more marked when the results were adjusted for differences in cigarette consumption, The results for sputum~ volume were disappoint-' TszT-stcuxz 3:-Averagr consumption of'eaeh of' the 3 types of,cigarette between the start of the arial,(November, 1969) and May 1971. TtxT-nczzxt 4:-AveragF nicodne con- tent of cigarette tips of 60, men; 20 smoking each type of cigarette.

1808 FREEDMAN, FLETCfiER, AND FIEL.D TtxT-natrnz 5.-Average coug#s frequency scores on the types of eigarette: DEVIATItDNS'. F4OMMEAN -08 -O• 00 J L A N O~ J F~ M A' Mi J J. A. S' o~ N o~ J F~ M1A M J. Ji 1969'' 1070 19711 ing, (text.fig. 7),. First, the 3 groups had d'ifferentt initial values, though we had hoped that these values would be similar once the men had been matched so closely in other ways. Second, there was a gradual decline in, mean vabues with no seasonal! variaition. By comparing, individual results wich the.answets in the monthly questionnaire, we concluded that this decline in volume of sputum representedl the increasing, failltre of the subjects to produce the specimens- There was no signifiicano difference between the groups for F:E.Va or F.E.V./V.C- ratiio, (text-fig. 8), A recent large-scale survey of over 7 years showed& that the difference in the annual rate of decline in F:E.V., between smokers of over 15 cigarettes per day and nonsmokers was only about 30, ml/year. The trial would have to be continued for much longer laefone differences between men smoking only slightly modified ciga- rettes couldi be detected. JpURNrtL OF THE NATIONAL CANCER L"VSTrrU'rE 1005052'95~9

.- I -4 7 tFFECrs oF sstoxtNtS UOD2FMa ctaiARE2*rEs We ended this trial in September 1971. VMany problems are: involved in trials such as the one we conducted'. The first and foremost problem is the ethical question. In this regard, none of' the cigarettes used in the experiments exceeded in tar and nicotine content the brands commercially available, and about half the men smoked cigarettes of lower strength, during the trial than they had' been smoking previously. Secondy two-thirds of the men showed little or no change in consumption of cigaaettes during the trial. One-third 'uncreased cigarette consumption, and we estimate from VOL, 48, , NO. 6, JUNE 1972 r8 1809 TuT-Ftctras 7:-Average, sputum production (measured as mm on an,arbitrary7inear seale). 'I'Ex2-novna 8: Average values,of F.E:V.I. chemical analysis of the butts that the dose of nicotine and tar to the smoker was unchanged. Thirdi since, at the start of the triau all the men were advised to stop smoking, we think that few, if any, of' the subjects would have spontaneously given up cigarette smoking if they had, not been included in the trial. The: second probiem is the measurement off response: Few of our subjects ha& objective evidence of airway obstruction as assessed by spirometry, and they were abnormal only by virtue 1005OS2960

1 ~J. I'81i0 FREEnMe\N; FLETCHERy A,YD F'IEL•D of their symptoms of' cough and production of sputumi These symptoms are di 'fficult to quantify, as our experience with measurement of sputum production showed. However, our method of assessing cough frequency is valid and sensitive, as shown by the seasonal changes, though this still awaits validation by some independent means of counting coughs. We have had limitert success with several methods tried. It is now becoming well recognized that spirom« etry is not a sensitive method for detection of early airway obstruction and that newer tech- niques, such as measurement of closing volume, flow-volume curves, or radi©active gas distribution at different speeds of'inspirat4on, are more sensitive. As yet, these techniques are unsuitable for use in targe•scale epidemiologic or field studies, for they must be further simiplifiedL Iat conclusion, we have shown that modification of the composition of cigarettes and their filters can reduce smokers' cough, an important and earl sym tom of bronchitls y p . ~~~,^^~+ry~ ` '~ ~~ ~y • *, ~.: , ~- ~I ~