Document 50DNrg8ZgqoqRj61qaELmO5vN

FILE NAME: Foster Wheeler (FW) DATE: 1954 DOC#: FW102 DOCUMENT DESCRIPTION: Journal Article - Occupations and Cigarette Smoking as Factors in Lung Cancer 'm /s Occupations and Cigarette Smoking as Factors in Lung Cancer liSTER BRESLOW, M.O., F-A.P.H.A., LeM A R H O A G L IN , G L A D Y S RASMUSSEN, and HERBERT K. A B R A M S, M.D^ F.A.P.H.A. . studies have implicated cigarette smok 71th four-year ttu d y offer* addi tional eridene* tending to connect Ira rj rigarrtto im olting with eonfrf. In addition, it list* several ortupulinni that teem to hava tom e etiological reta tio a th lp to thm die- They need further ttu dy, at it it tuggrited. ing *' and certain occupations a -- es pecially those involving exposure to radioactive1 and chromate ores * and asbestos *--in the causation of lung cancer. Hoxvcver, the number of per sons known to have such occupational exposures in the United States is rela tively smalL The sharp increase in lung cancer Tlie present investigation was under nurultly constitutes one of the most taken four years ago: (1) to determine -j-rtarular disease phenomena of the whether any additional occupations al two decades. In the United States might be involved in lung cancer and it.'wa- ae^ec-adujusted mortality rate for lung thus deserve intensive investigation, and . ' V Jjiiii'cTr fl-ilnimibbed from 2.7 per 100,000 (2) to obtain data- on the role of f L |>u-Lit'inn irn 1930 to 11.0 in 1948, a tobacco usage in lung cancer. n.-rctluni ffooiurfold increase. In at least ae Mate, California, pulmonary cancer i.w arrounts for more deaths titan does I'ulntiirtary tuberculosis, and among aged <15-64 it causes 4 per cent of all (U-atllS. Methodological Considerations Definitive study of whether an occu pation or cigarette smoking is a causa tive factor in lung cancer requires that Attempts to explain this rising mor tality as spurious, e.g., as due to imwed diagnosis of the disease, do not ManJ up. The lung cancer death rate-- hi*h unfortunately is still our best the incidence rate for the exposed group be determined. This rate is then com pared with that of a control population, the most acceptable control being all the rest of the population from which the -`|>r..\itnalion of incidence rate -- has merra>cd two and a half times more rapidly among men than among women. | can liardly presume that physicians o\e apjilied diagnostic improvements ' inch more completely to men than w.mwn. Likewise, the increasing proI--fti,.n of lung cancer found as a cause -ail among autopsies supports the `'a usi,,n that we are dealing with a 'I increase in the disease.1 Lnir,.,,mental changes appear to r the Lost explanation for the wmnwnon. Previously published Dr. Breslow is chief. Bureau of Chronic Disrases, California Slate Department of Pub lic Health, Berkeley, Calif.; and Mr. Ifosglin and Mrs. Rssmusscn are also associated with this department. Dr. Abrams, who was formerly chief. Bureau of Adult Health, California State Department of Public Health, is now medical director, Health and Welfare Fund, Chicago Office, Theater and Amusement Building Janitora' Union, Local 25, Chicago, 111. This paper is based on a study supported by a research grant <CS 9047) from the Na tional Cancer Institute, PUS. and was pre sented before the Industrial Hygiene Section of the American Publie Health Association at the Eiglily-fi Annual Meeting in New York. N. Y-, November 10, J9S3. ( L - //- .ZJtGZZt. .J tX S S S .a .; 172 F E D , 1954 AMERICAN JOURNAL OK PUBLIC HEALTH exposed group came. Assuming the same diagnostic and reporting standards for both groups, one may thus deter mine how the chance that a member of an exposed group will develop lung cancer compares with the chance that such a person would develop the dis ease if he were not a member of the exposed group. If the likelihood of de veloping lung cancer is substantially in creased by being in the exposed group (e.g., a certain occupation) one may conclude that the exposure is a causative factor in the disease. The key to this analysis lies in determining comparative incidence rates for a suspect group and a control population. But first it is necessary to identify suspect exposed groups. That was the aim of the present study. The im portance of pin pointing these groups arises from the fact that incidence studies require assembling sizable popu lations and observing the occurrence of the disease in them--a large and ex pensive task. If, for example, data were obtained implicating occupations beyond those already known to be causative factors in lung cancer, one would be justified in assembling popu lations of the occupational groups and observing them for lung cancer inci dence rotes--a study which would de velop more definite proof of the presence or absence of an etiological relationship. Several methods of investigation have advanced our knowledge in this sphere. First, is clinical observation of associa tion between a case or a few cases of lung cancer and some exposure, e.g., asbestos. One defect of this method is that such clinical observation depends largely on chance and often involves such small numbers of cases that the validity is questioned. Where made, of course, such observations are helpfuL Another common method of identi fying suspect occupations in a highly fatal disease, such as lung cancer, is to note the frequency of the various occu pations on death certificates where the disease appears as the cause of death. The frequencies of the occupations on such death certificates may then be cora- pare4 w*th those on all death certificates for the general population. If certain occupations appear with much greater frequency on death certificates for lung cancer than on certificates where death is due to other causes, one may conclude that the occupation may be involved and should be intensively investigated. Important achievements may be credited to the use of this method. However, major difficulties with this use of death certificate data arise from the following circumstances: only one occupation may be recorded; while this is supposed to be the "usual occupation," it is often not correctly recorded and duration in the occupation is not recorded. All these circumstances tend to blur the identifi. cation of suspect occupations from death certificates. * The method selected in the present study was to determine the lifelong occupational and tobacco-usage history of lung cancer patients (and a control group) by actual interview with the patients. The work history included the number of years engaged, name of com pany, industry,-a description of duties, and listing of products and hazardous materials known to the patient. Dale Collection Patients observed during 1949-1952 in 11 California hospitals (three county general hospitals, five veteran or mili tary, two university, and one. private hospital) comprised the study group. An interviewer especially qualified in occupational analysis obtained the data frotn^ each patient in the cooperating hospitals whose condition permitted the interview. The session with each pa tient often lasted two hours or more, since many details about smoking were obtained ad the information about every occupation was highly detailed. A total o{ 518 patients who finally had hbtopathologically proved diagnoses of lung cancer were ultimately included in the analysis. For every patient in the case series another patient admitted to the hospital about the same time--of the same age (within five years), sex, and race--for a condition other than cancer or a chest disease was chosen in a random manner as a matched "control." Two inter viewers, one working in Northern Cali fornia and on in Southern California hospitals, obtained the data from tho lung cancer patient and control patients using the same schedule in identical manner. That interviewer bias did not enter into the determination of tobaccousage history seems likely, among other reasons, because the results closely parallel those obtained in other investi gations where such bias apparently was excluded,44 and because the results for the two interviewers were very similar. It is difficult to conceive how inter viewer bias might have affected the occupational data, since both lung cancer patients and control patients mentioned hundreds of occupations and none of these was suspected by the in terviewers. Preliminary findings were kept from tha interviewers until the end of the data collection. Method of Analysis Each record was reviewed by a physician, particularly with respect to the pathologic diagnosis. An industrial hygiene chemist completed the listing of materials usually involved in tho occupations mentioned by the patients but not necessarily known to them. Thereafter, the data were coded and tabulations prepared. _ Attempts to analyze the data concern ing type of industry and exposure to materials already identified as toxic or carcinogenic did not prove fruitfuL Hence the major analytical effort with respect to work history went into the data on occupation itself. This had been coded according to the Dictionary of Occupational Titles (2nd ed., 1949), prepared by the Division of Occupa tional Analysis, U. S. Employment Service, a code with 367 three-digit titles. Particular attention was devoted to the question of years of exposure be cause present knowledge of carcino genesis due to environmental agents in dicates that duration of exposure and a long latent period are critical factors. Data on tobacco usage were analyzed so as to reveal the type end degree of smoking, as well as the fact of smoking itself. Finally, an attempt was made to sepa rate the effects of tobacco usage and occupations which appeared implicated. Taltl 1 Age D istribution o f Lung Cancer Patients and Controls Cases Controls Aj caArcdiennoom- a oOf tChaerrcTinyopmesa Total T ottl Total 46 472 518 518 Votier 40 * 3 22 25 26 .'4- 4049 6 56 62 59 50-59 19 194 213 213 60-69 H 154 168 169 70 tn d over 4 46 50 51 &MM Sex and Race Total Total male White Negro Other Total Female White Negro Other Adeno* carcinomi 46 42 41 1 4 3 1 * Other Types of Carcinoma 472 4SI 420 20 11 21 IS 3 3 Total 513 493 461 20 12 2S 13 4 3 Control* Total 513 493 461 20 12 25 18 4 3 Findings on Smoking Tables 1 and 2 reveal the distribution of the lung cancer patients according to their biological characteristics -- age, sex, race, and the essential similarity of the matched control series in respect to these characteristics. Tobacco usage by lung cancer pa tients and the control group is shown in Table 3. Here one may note that 4SI (93 per cent) of the cases gave his- tories of having smoked cigarettes; whereas only 394 (76 per cent) of the controls gave a similar history. No such greater frequency of tobacco usage in other forms (pipe, cigar, chew, and snuff) occurs among the lung cancer patients when compared with the con trol group. In fact, 68 of the control group used tobacco in a form other than cigarettes exclusively; whereas only 15 of the lung cancer patients did so-- relative frequencies which are not much T a b le 3-- T o b a c c o U sage D u rin g 2 0 Y ears P rio r to Study R e p o rte d by L ung C ancer Patients and Controls - Manner of Uting Tobacco Total Total not smoking - cigarette* ...... No use of tobacco Tobacco other than cigarettes, only Total amoking cigarette* Cigarettes, only Cigarette* and other Adeno* carcinoma 46 6 4 2 40 31 9 Case* Other Types of Carcinoma 472 28 15 13 446 * 208 116 Total 518 34 19 15 431 329 155 Control* Total 518 124 56 68 394 240 154 LUNC CANCER V OL 44 17S T ahla -- Am ount o f O g arett Sm oking D uring 20 Year P rio r to Stody R eported by L ung Cancer P atien ti and Control Package e l Cigarette Smoked per Day Number Per cent ' _________ Control Number Per cent Total 518 100 518 100 Nona 34 7 124 24 <V4 19 4 50 10 Vi - 71 M 105 20 1 - 30 59 199 38 2 or more 80 15 22 4 Not recorded 10 2 18 3 different for the nonusers of tobacco in the two series. ' TItis suggestion of on effect by cig- arctics only is consistent with other in* vrstigations in the field. Some support for the hypothesis that cigarette smok* ing affects the development of epithelial carcinoma of the lung more than ade nocarcinoma may be noted. Six out f 46 (13 per cent) of the cases of adenocarcinoma did not smoke cig arettes; whereas only 28 out of 472 i6 per cent) of the patients with other t;pcs of carcinoma, described variously a* squamous, epithelial, undifferen tiated, did not smoke cigarettes. One commonly used measure of the amount of exposure to cigarette smok ing, the average number of packs smoked per day, appears in Table 4. Seventy-four per cent of all lung cancer putients reported smoking one or more packs of cigarettes on the average per day over the preceding 20 years, com pared with a frequency of only 42 per cent among the controls. " Excessive cigarette smoking" (two or more packs per day) occurred almost four times as commonly among the case series as among the control group. Other items which may indicate the uinount of cigarette smoking include the age at which tire individual began smoking, whether or not he smokes be fore breakfast, and whether or not he " inhales." Table 5 reveals that, by all la id 5-- Age o f B eginning C ig arette Sm oking, Sm oking IToblta, an d " Cignretto C ough" R eported by L ung C ancer Patient and Control Cljrarelto Smoking Characteristic Number Total 518 Total cigarette smokers 484 15 yeir* of age 166 15-24 286 ... 2S year* of aso 32 inhale* 449 Brooke before Lreakfait'" 373 >-`gir.1te cough" 204 Casea Per cent Based on Cigarette Smoker Only 100 34 59 7 93 77 42 Percent Baaed on Total 100 93 32 55 6 87 72 39 Number Contrla Per cent Based on Cigarette Smoker Only 518 394 100 116 29 243 62 35 9 327 83 229 58 112 28 Per cent Bated on Total 100 76 22 47 7 63 4-1 22 176 F E B , 1954 AMERICAN JOURNAL OF PUBLIC HEALTH T abi 6-- E stim ated P revalence lites * o f Lung C ancer p er 100,000 Malea ( Selected A(e* and V arious C igarette Smoking flahit* Number Lang Cancer Control Estimated Prevalence Rate* Quantity Smoked Daily t All QuanHeavy titiea None Relative Prevalence t Heavy AB Quantit ie* Patienta aged 50-59 yeara 1. Doll and Hill 276 275 94 42 7 13 6 2. U'ynder and Graham 258 210 117 47 27 11 3. Sadowsky, Gilliam, and Cornfield 198 208 87 44 12 7 4 4. Present ` 213 213 102 46 6 17 7 Patienta aged 60-69 yeara 1. Doll and Hill 197 199 137 63 0 . 2. V ynder and Graham 187 160 138 70 5 29 IS 3. Sadowsky, Cilliam, and Cornfield 76 71 44 71 5 9 4 4. Present 168 169 433 78 17 25 5 * L *U j*ttrd accordici t * tb *1 C radU.u D *U l r ad* I I M I *d K M ; V f d r u 4 C a lu m i u 4 W w U , G U IU a . u d C s tv ia id in m ih U t ic r h h <u ' Q m o titf M i d d a ilr, scapi fa* f r m a i a ta d f. U il fa m a of tmafaiaf r r g raiw d a cifaratta*. witkp+paa ami tir a la aa*ri*d la tb alr aq a iv ala * u ifarwttaa aa fo lla at 1. D all aad HIU--I oa. al tab acca a waafc s s 4 iftrvUa a 4 r i 2. W radar u d CraKav i ti f a r = 1 d e tra tte * , & pi p alai = 2*-4 d fa ra tta a ; ad )> S a d w a f , CiUUaa. a ad CaniAald--l c ita r = 10 ii|ir H M , 1 aa. pipa tabacca = 20 ciparetta*. 4. F ar praacst ta d f, fm a a liif -- a ed dall? laelada oaly elftratta auakiaf* I Relativa prcralaaca la fba ra lla ! H * * v f -- tsia aaiang k ia r y raakara/rata a a a a g W M a b n | ZI f ta a iiila a -- m a aataaf Miokara/rata a a a f aaam akar H ta v y aaiaU a f ia daftaad aa tk a fa lla ta la ! b a r a l c lf t r a t ta t ar a * * *Ita ta a l c ifa rctta a par 4 f *--t . D a ll aad H i ll--0 a a r a i 2. W ra d a r ad Crabam --SS a r a r a ; 9. Sadaw*ky, C lU la u , aad C c n l < l i * 4 1 ac a r a i ad 4* pr rcaal lady--44 a r a ra . of these criteria, the lung cancer pa tients smoked cigarette* to a greater ex tent than did the control group. Also, approximately two-fifth* of the lung cancer patients stated that they had had a "cigarette cough" usually antedating the onset of their illness by many years; 120 said that they had had a cough for five years or more. The frequency of such "cigarette cough" was only about one-half as great among the control group and only 39 of the control pa tients indicated that their cough had lasted five years or more. Significance of Findings on Cigarette Smoking The data clearly show cigarette smok ing to be more frequent and intense among lung cancer patients than among the control group. Our data parallel that of other recent, well controlled studies; all indicate a positive correla tion between cigarette smoking and lung cancer, a correlation which increases steadily with the amount of cigarette smoking. One can hardly escape the conclusion of Doll and H ill4 that "smoking is a factor and an important factor in the production of carcinoma of the lung," and the more recent con clusion of Doll,10 "The results amount, I believe, to proof that raoking is a cause of bronchial carcinoma." The cigarette smoker or prospective cigarette smoker may wish to know how much his chances of developing lung cancer are increased by such smoking. Acknowledging that a correlation exists, one may still inquire how many times does cigarette smoking increase the LUNC CANCER VOL 177 likelihood of lung cancer? Further, what is that likelihood in absolute terms? To answer these questions definitely would require that records of cigarette smoking for large numbers of persous in the lung cancer age be assembled. These persons would then be placed in categories with respect to cigarette smoking, e.g., nonsmokers, moderate smokers, and heavy smokers. Finally they would be observed for a sufficient length of time to determine the rate of lung caucer among the various categories of cigarette smokers and the nonsmokers. (Such studies are now under way.) . However, statistical devices have been developed for data sucii as those in the present investigation which, if one is willing to make certain assumptions, yield an answer to the question, how many times docs cigarette smoking in* crease the likelihood of lung cancer? Application of Cornfield's formula n ' iS to die data from four studies, including the present one (Table 6 ), indicates that for men aged 50-59 the prevalence of lung cancer is from four to 11 times aa great among smokers as among non smokers, and from seven to 27 times as great among heavy smokers as among nonsmokers. Similar ratios were found for the 60-69 age group. This formula involves the assumption that in so far as smoking history is concerned, the pa tients are a representative sample of all lung cancer cases and the controls are a representative sample of all other per sons in the general population. Findings on Occupations As noted earlier, the records for lung cancer patient and controls showed all Tablo 7-- Twenty P er cent Sam ple from Complete List of O ccupational Group* 1 In W hich T here W ere at L eatt 5 Case* o r 5 C ontrols Em ployed fo r 5 Y ears o r M ore Occupation Persons Employed in Occupation st L en t _______ S Years______ Cases Controls 006 Authors, editors, snd reporters 7 9 088 SUip captains, mates, pilot*, sn d engineers 8 8 10S Clerks, general office 2 8 1SS Canvasser* a n j solicitors 3 11 180 Salesmen to consumers 7 4 227 Waiters and waitresses, except private family 14 10 266 Policemen and detectives, public service 6 3 307 Animal sad livestock farmers 6 S 317 Farm ltanda, animal snd livestock 10 10 433 General woodworking occupations, not elsewhere classified 0 7 516 Painters, except co tu tn clk m and maintenance 3 6 524 Brick sn d stonemasons and tile setters 5 1 532 Construction occupations, not elsewhere classified 45 25 542 ljucomotive firemen 3 6 560 Attendants, filling stationsand parking lots 10 9 583 Mechanics and repairmen, not elsewhere classified 15 16 * * * * * S u s * ! * n u l J r * r U c l*4 (ra n Ik * S I * a * a t l* a f r o s t s s h ir k last Ik s r lr l . t t n e s s a r y . 4 s *slla a a < a ln a . . l . (at k a n l ra sa , s r S c a s u a ls with S fo a TM -a la rsira i). O ar***- Haas cla a a U r* s m n S la * ta X 4 i rt u l a i s r k s la Ik s O k lla a a ry a! O tta fa lia a a l TltW a < l l4 #4.). W a . M * ( i* a . O . C l U . 3 , E * * * U r n a * l S a r r k a . 1SIV. 178 FF.I1., 1954 AMF.RICAN JOURNAL OF PUDI.IC HEALTH TuUlc 8-- O ccupation Croup* * In W hich th e F m pjcncy of S Year E m p lo y m e n t A m on* Case* W m at Lenst Twice a* Great aa Amon* Control* Occupation Person F.inployed in Occupation at Least 5 Years Cates Controls 016 Engineers, civil 5 1 138 Stock clerk* 7 3 266 Policemen and detective*, public service 6 3 430 Lumbermen, raftsmen, and wood chopper* 11 5 478 Machine hop and related occupation*, not elsewhere classified 8 3 483 Welders and flame cutters 10 1 520 Occupations in production of petroleum 5 2 523 Construction machinery operators, not elsewhere classified 7 3 524 Brick and stonemasons and tile setters 5 1 538 BraIcemen, railroad 10 5 570 Firemen, other than process firemen 11 2 573 Cranemen, derrickmen, hoistmen, and shovelmen 15 6 575 Drillers, extraction of minerals and construction 7 2 O rrpiiM rc* U n r 1 |Im D k tU aary W OccapaUe**! TttU ( 2*4 #4. ) . T h in iu u D. C .i U. S. Eaptoyiftvat Sarvlca, I W i lacU rfat aaly * a * p e iia e e 1 b ltia t h i n a m a t WiM S u w with S j m i i t r o ra #J aiayiayaiaat, . occupations followed and their dura* tions in years. A listing was prepared of the occupations pursued by at least five patients or controls for five years or more. This listing revealed 81 occu pations in this arbitrary frcqucncy-andduration category. Table 7 presents a random sample of these occupations and the number of patients and controls who at some time during their work history had been en gaged in them for five years or more. It will be noted that among the 518 lung cancer patients seven had worked as authors, editors, or reporters (occu pation) for five years or more, and among the 518 controls, nine had been similarly engaged. Relative frequencies of occupation would appear to have the same logical significance as such fre quencies of cigarette smoking. The lat ter is, of course, much more common among both case and control groups than is any single occupation. Hence, the numbers pertaining to any one oc cupation would be less impressive than in the case of cigarette smoking. How ever, the frequency with which the lung cancer patients had pursued certain oc cupations was substantially greater than the frequency with which control pa tients had pursued these same occupa tions. The occupations for which the fre quency among cases was at least twice as great as among controls, using the same frequency-duration category as before, appear in Table 8. Such a tabu lation, of course, shows the occupations classified according to an arbitrary code which was not devised to reflect com mon occupational exposures that might be responsible for lung cancer. Further analysis therefore included the de tailed examination of records of in dividual cases and controls and re grouping of occupations according to possible common exposures. For ex- LUNG CANCER VOL. 44 179 ample, one occupational group, number 530 (plumbers, gas fitters, and steam fitters) showed 16 cases and 10 controls with a five-year employment history. Examination of these 26 individual records m ealed that substantially all the difference between case and control scries was due to the steam fitters who lmd a heavy exposure to asbestos. It was also noted that other types of work involving asbestos occurred more fre quently in the employment history of cases than among the employment his tory of controls. Thus, a new category, including steam fitters, asbestos workers, and boilermakers--all involving expo sure to asbestos--was found to occur 10 times among the cases and only one lime among the controls. Table 9 presents the data for occupa tions grouped according to possibly significant exposures. Although num bers in each of the categories are small, the differences between cases and con trols appear to implicate the occupations listed. It ts of interest to note that several of those with the most striking differences involve exposure to metallic particles and fumes and products of metallic combustion. This observation tends to corroborate the suggestion of Wynder and Graham13 that "hot metal" occupations may be involved in lung cancer. In recent data of D oll10 the only occupation with an important excess in the cancer group was that directly con cerned with the production of gas. Little or no support was found indicating that other occupations suffer special risks. However, Doll's study was based upon experience in England where the em ployment pattern differs from that in the United States, especially California. Also, Doll used an occupation code of only 76 categories which may have been too coarse to reveal the differences found in the present investigation where a code of 367 categories was used and analysis carried to subgroupings of these. It may be noted that 77 persons with lung cancer had an exposure of more than five years to suspect occupations (unduplicatcd couut in seven occupa tion groups) according to the data in Table 9. This number represents a not insignificant proportion of the total (518) lung cancer patients in the entire study. # A further question upon which the present data might be expected to throw some light is the extent to which ciga rette smoking and occupations operate T able 9-- Cases and C ontrols Employed fo r at Least S Years la Scleeted O ccupation G roups Occupation 1. Welders snd sheet metsl workers doing welding 2. S te m filters boilerm akers snd asbestos workers 3. Electric bridge crane operators--metal industry 4. Occupations in the extraction of lead, rinc, a n j copper ore . 5. Marine m -incars. firemen, o ilers an wipers Construction and maintenance paintersj 1 Cooks commercial (exciudm* cannery cooks! nOMsisi MSS'*1 '* *' i m irtlils4 hmihIm 1 rsearis. Persons Employed ia Occupation at Least S Years Cues Controls 14 2 10 1 S 1 9 3 12 6 ->*> 12 35 21 M r e p t l l M i l i p M i n i ft 180 F E B , 1951 AMERICAN JOURNAL OK PUBLIC HEALTH T abla 10-- E xam ple o f A d jin im rn t fo r Sm oking Applied lo Welder mnd Sbect Melai W orker D oing W elding None Pack*M of Cigarette, Smoked per Day < 1 4 14 -- 1 -- 2 or more Not re* corded Total All cases and controls, male L Cases 2. Controls 3. Total 4. Proportion of cases among total cases and controls Welders and sheet metal workers doing welding, male 5. Cases 6. Controls 7. Total 8. Expected number of welder cases t 22 110 132 0.167 0 1 1 0.167 16 69 296 80 45 105 193 22 61 174 489 102 0.263 0.396 0.605 0.783 0 2 11 1 0 0 1 0 0 2 12 1 0.0 0.792 7.260 0.783 10 493 18 493 23 986 0.357 0 14 0 2 0 16 0.0 9.002 Expctt4 f.OW ! ( m i m m | v U m zz .....n I .K 1 1* 1 1ft n . O karrvrJ pprtsMi ! r u n n * | wrUIr* = -- s s .STS N iM ty - iv a p * r ce l r n i J m Um * | f r Ik p r v p w iU * -- = : (0.41T, # . tW ) -- u tfa ik a lly i l p l i u a i n (I * F *W K l a M fv t l f r w p , l*c M i r Ir art U c U d W 1 f r* *p 1 w k k b (rat u a p p M , O b u i fcp a p y ly t* * Ik * p*p*n l -- I u m u i m ( ta ta l t i M i n i U M k M *klm | caU farf * k ti 1 w IJr* la tk*t B a kia e a lrfo rp (tiaa N * . 4 X Urn* No. ?] | K iU , A . S titiM lc il T akU * m 4 F n i U i. N t * Yarkc J*ha V iliy , l i y , N***: Tki* Mat *Jw * n applied la all aik ar acrap atiaa croup aka la TakJ* 9. TV* fra a p " u aja kfUra*k*ra aakauaa w arkm** waa a a th a k ard attlaa of uttatical a lf il r a te al tha W par ao a t U raL Mo m d o r (roup* a t ik* tS par r r a ( iv| af a(a4(ari<`al affaificaac*. M M M Itu n , a! tk* as separate factors in lung cancer. For example, both cigarette smoking and welding appear to be related to the disease, but do welders get lung cancer more frequently merely because as a group they are heavy cigarette smokers? Although data from the present study involve small numbers for many of the occupations, analysis does indicate that welding as art occupation operates as a factor distinct from cigarette smoking in relation to lung cancer (Table 10). The group of steam fitters, boilermakers, and asbestos workers lies on the border* line of statistical significance when the .effect of cigarette smoking is controlled. In the other occupational groups the numbers are such that the differences might arise from chance variation more than five times in a hundred. However, all the occupations listed in Table 9 deserve intensive study to determine their precise relationship to lung cancer. One important step is to assemble populations of individuals em ployed in these occupations, and with varied smoking histories, in order to observe their lung cancer incidence rates. These rates may then be com pared with the rate for the correspond ing age-sex group in the general population. One may thus determine LUNG CANCER V O L 44 181 how being in a particular occupational roup aiTccta the chances of developing lung cancer and likewise how cigarette .linking modifies these chances. Conclusion The data in this study constitute still another link in the chain of evidence connecting lung cancer with cigarette smoking, evidence which the New Eng land Journal of Medicine notes to be "io strong as to be considered proof within the everyday meaning of the word." M It is time for those concerned with health education- and with the ethics of advertising, at least in health and medical journals, to take note. Further investigation should seek the exact component of cigarette sm o k e tar, arsenic, or other--which is respon sible. The data also suggest that several occupations (Table 9 ), in addition to those previously identified os having an etiological relationship, may be involved in the development of lung cancer. Tlicse occupations should now be in tensively studied to determine to what extent persons engaged in them sutler a special risk of lung cancer. There after, if an etiological relationship is clearly established, the precise exposure and mechanism responsible should be identified in order that protective meas ures may be introduced. REFERENCES 1. Dtff, M. L , Doll, R., K ra n w if, . 1. Cancer of tb* Lung la ReUlina l a Tabacca B ri. J . C ascar 3:1, 1931. 2. Schrrk. R - Dakar. L. A., Ballard, C. P.. and Dolgo!!. S* Tobacco Stocking a t aa Cflylocieal F ac tor la Dtaaaao. Caocer Rracarcb 10:49*34. 1930 1 Wjrodcr, E . L .. end G ra tin i, L A. Tobacco Suok log m Poaaiblo FtloU gic Factor In B roocbiograio Carcinoma. A Sts)? of 661 Proved Ca*ao. J.A.U.A 1 0 J : i * 3 J 6 . 1930. Dofl. X-, aad H ill. A. B. A Study of ttaa Avtlotogy o f Catrin o oso od tb o L o a f. B rit. M. J . Z 1271-1296, 1932. 5. Lavia, U . L . CoM tteio, !(., and C rrhardt, P, R. Caocer and Tobacco Smoking. A ftaU rain aty Ra* port. J.A .M .A . 143:336-331. 1950. 6. H a tp e r, XT. C. O ceopatlnnol Tsmoco and AUiod Dleeaaoo. S p rlag leld . U t.i Tbomaa. 1913. 7. Rootoeki, 0 - , Saapa, ., aad Srhmoel. C . Dio UrrgL/ofikhet ter CribcrgU oto la Srhneebery la Bocbaen ( " Scbneobcrger Loogeobraba" ) . Ztocbr. f. KrabMoracb 23-J66-<4l. 1929 I . M arkU . W ., aod Cregorloas, F . C ascar od tbo Respiratory Syetem ia tb a Lotted Stole. Pub. Hooltb Rep. 43:1114-1127, 1 9 0 . 4. Cloy*, S. R . Psoumoroalooi} Biatoloylcol Surrey od Neoropey M aterial la 1293 Coaea. L aarel 1:410, 1951. 10. Doll, B. Broacblol C orrlaotnot Zaoidroeo aad AetU oloyy. Port I aod P art II. B rit. M. J . S21-52T, 593-590, 1933. 11. Cocmtald. A U etbod ad C etlao tlag C o m p rali* Rateo (rota CUoleal Dato. Appllcotioa to Caeccr ol tbo U i f , Broom, ad C orri*, j . J i.i. Caocer !aat. 11:1:69 1273. 1951. 12. Sadovreky, D.. C iJIU a. A., aod Coroftold. J . Tbo Statletieol Aaooolotioa Between Smoking and Car rinomo of tbo Lung. fb ld . 13:1237-125. 1953. 13. V p id e r . . and C rabara. . A . Eliologtc Factor* la BroneMoymio Carcioomo witb Special Referaoce la loduairioi Eapowirva; Report ol 137 Proved Coo*. Arab, In d u rt. llyg. A Oc* up. Mod. 4:22!. 1951. I t . Edltoriol. Caocer ol tb a Laa. New England J . Med. I I H i l - l f A , 1933. Journal 25 Years A g o Addendum to the January, 1954 "25 Years Ago." In addition to the articles n the common cold mentioned last month, the 1929 Journal (p. 419) describes an eight-page booklet "That Mean Cold," by present-day associate editor of the Journal, Raymond S. Patterson. It was reportedly his first production as director of health education for the John Hancock Mutual Life Insurance Company, the January issue (p. 94) having reported his appointment as director of health lueation, Life Conservation Service of thnt company. Dr. Patterson had already been the author of A.J.P.H.'s "Annotated Public Health Bibliography" for several .ears, it having first appeared under his by-line in March, 1926.