Document 2qjG5mwp1E5kpr6gaOg9n9b17

Occupations and Cigarette Smoking as Factors in Lung Cancer , cctm SRESLOW, M.O., F>.P.H>.. LsMAR HOAGUN. GLADYS ^SMUSSEN, end HERBERT JC ABRAMS. M.0,, P.A.P.H.A. studies have implicated cigarette sreok* fki wwdr Wrffc ft-fj wdeaea rending JO " i,,*rr a******* ******* with een* r+r. Im eddiiian, H HWa mrwrwl *rmpm*th*t MR I* h*t* mm* riHUmriml r*Uiiw**kl* t* the dls* r*+*. Tkrr aoed fttrikm uudf, as U i* mtgttMrd. ing *'* and certain occupations* -- ' pecially those involving exposure to radioactiveT and chromate ores * and asbestos *--in the causation of lung cancer. However, the number of per* sons known to have such occupational exposures in die United States is rela* tivcly small 11u* Harp increase in lung cancer fiuiity cn*utwt* one o( the moat iiaruljf disease phenomena of the i'jM iho dcradea. la the United State* ace-adjusted mortality rate for lung > r climbed from 2.7 per 100.000 : fuLtion in 1930 to 11.0 in 1948. a The present investigation was under* taken four years ago: (1) to determine whether any additional occupations might be involved in lung cancer and thus deserve intensive investigation, and (2) to obtain date on the role of tobacco usage in lung cancer. - than fourfold increase. In at least :ir Matr, California, pulmonary cancer Methodological Considerations < <** srTbiiuu for more deaths than does j ilutunary tuberculosis, and among 1 aped 45-84 it causes 4 per cent of j!! loath*. \ttmipu to explain this rising mor* rjlu) Hf <puriooa, tg., as due to ia* ' "l diagnosis of tbe disease, do not up. The lung cancer death rat*-- v>ii<h unfortunately is still our best Definitive study of whether an oeeu* pation or cigarette smoking is a cause* live factor in lung cancer requires that tlae incidence rate for the exposed group be determined. This rate is then com* pared with tliat of a control population, tite most acceptable control being all the rest of the population from which the ; ;>r*>viinaiion of incidence rata --has *>rr>-an.'tl two and a half times mom smoflg men than among women. K- 'jii liarJJy presume that physicians :'v u|*j>iicd diagnostic improvements * ' "k-U more completely to men than -"men. Likewise, Um increasing pro> >-<ri<.n of lung cancer found as a cause 1 `taih among autopsies supports tlie '< lui**n that we are dealing with a -il tocrease in the disease.1 J-m ir>>mncnt*l changes appear to -r the best explanation for lha : *' *"""**. Previously published Dr. Bmlsw chief. Boms ef Giresie Diirseaa. California Stele Deesnaeat ef Pub* lie Health. Berk#let. Calif.; sad Mr. Uesglia and Mrs. Raaaawa in alas associated with this depanmesi. Dr. Abram, whe was feniwwly chief. Bureaa ef Adult Health. California State D*?*iwn*m f Public Health, is aew medical direaer, Health sad Welfare Fund. Chicago Otter. Theeter sad Amuscmcat Buildieg janitor*1 Ueieo. Leesi 23. Oiicage. Ill This paper fa based se a study supported by s mnrrb mat (CS 9047) /rent ibe Ns* tienal Caaccr lastttaie. PUS, tad was pro* ented before tbe Industrial Hygiene S^etioa of the Americas Public Health Association at the igiity>fir*i Annual Meeting ia New York, N. Y, Nevoniw 10, 19S3. 171 171 FEB, !4 AMERICAN JOURNAL OK PUBLIC HEALTH urpimrt group came. Aauming the seme diagnostic and reporting standard* for both groups, one may thus deter* aim v:w the chance that a member of an ei^osed group will derelop lung earner compares with the chance that such a person would develop the dieease if he were not a member of the exposed group. H the likelihood of do* eloping lung eancer it substantially in* creased by being m the exposed group (e^, 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 rata for t suspect group and a control population. But first it is necessary to identify impact exposed groups. That was the aim of the present study. The to* portanee of pin pointing these groups arias from the fact that incidence studia require assembling liable populatioos and observing tbs occurrence of tha disease in them s large and ex* pensive task. If, for example, data were obtained implicating occupations beyond those abeady known to be causative factors in long cancer, one would be justified in assembling popu lations of the occupational groups and obeerring them for hing cancer inci dence rates--* 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 casa of lung cancer and some exposure, e.g., tibotoi. One defect of this method is that such clinical observation depends largely on chance and often involves such wnall numbers of casa that the validity questioned. Where made, of course, such observations are helpful Another common method of identi fying suspect occupation# in a highly fatal disease, such as lung cancer, is to note the frequency of the various occu pations on death eerti/icales wliere the disease appears a the cause of death. The frequencies of the occupations on uch death certifieata may then be com pared w'th those on all death certifieata for the general population. If certain occupations appear with much greater frequency on death certifieata 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 iatensively investigated. Important achievements may be credited to the use of this method. However, major diffeultia with this ua of death certificate data aria from the following circumstances: only one occupation may be recorded; while this is supposed to be the Musual occupation," it is often not correctly recorded and duration a the occupation is not recorded. All these circumstances lend to blur the ideatifi- 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 caneer 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,-* description of duties, and listing of products and haardou* materials knovm to the patient Oats Collection >y Patients observed during 1949-19S2 in 11 California hospitals (three eounty 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 from 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 sbout smoking were LUNG CANOS VOL. 44 173 .kuiasd and the mformatien about ^ wop.** vii highly detailed. A total o( SIS patients who fiaalty had hUiopatholofieally proved diagnoses of !un| eancer ware ultimately included is the analysis. for every patimt is the ease teries oother patient admitted to the hoepital thowt the *ame time of tl* same ago (within five yean), test, and raee--for condition other than cancer or a cheat wee ehoetn is a random manner cs a matched "control." Two inter* viewers, one working in Northers Call* fania and ora is Soothers California hospitals, obtained the data from the lung cancer patient and control patients wing the mom achedola in identical manner. That interviewer bias did not rater into tha uctermination of tobacco* UMgc bulory ictfli likely, among other tombs, bocaoee tha results closely parallel those obtained in other invaeti* gitions where inch bias apparently waa excluded,4* and became the reeolta for the two interviewed were very similar, h is difficult to conceive how inter* viewer bias might have affected the occupational data, tinea both long cancer pattesta and control patients mentioned hundreds of occupations and none of these wee suspected by the fm treviewer*. Preliminary findings were kept from the interviewer* until the end of the data collection. Method of Anoiytit Each record was reviewed by e physician, particularly with respect to the pathologic diagnosis. An industrial hygiene chemist completed the listing of materials usually involved in the occupations mentioned by the patients but not necessarily known to them. Thereafter, the data were coded and tabulationa prepared. Attempts to analyse the date concent* 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 e<L, 1949), prepared by the Diviaioa of Occupa tional Analysts, U. S. Employment Service, a code with 36? three-digit titles Particular attention wee devoted to the question of yean of exposure he* cause present knowledge of eareino* genesis doe to environmental agents in* dicstes that duration of exposure and e long latent period ere critical factors. Date on tobacco usage were analysed o aa to reveal tha type end degree of smoking, a* weQ as the feet of smoking itself. Finally, an attempt was made to sepa rate tha effects of tobeeeo usage and occupations which appeared implicated. Table 1--Ae Dfctrifeuite* at LSf Cmw Patterns n4 Cmteals A*s Tsui UaCcrte 40-49 M49 60*49 Aden* mrtinmm 44 *3 4 19 14 Casas Olbwfypss fCsiefema 473 23 34 194 m Tout 514 S 43 313 141 Caotrtis Tsui 311 36 39 213 149 174 FIB, 54 AMERICAN JOURNAL Of PUBUC HEALTH Table > Sw ih4 Ami DlefriWtloo el La Coo--r Paiieot* **d Ceotroli Sts cad Ran Total Tefal salt Whitt Ncgra Other . Taut Female White Nrp* Othr- Adww eafeiaetea 46 42 41 ,* 1 4 2 1 Caeca Odor Tyfc* el Careiacau 472 4S1 430 20 11 21 IS S 2 Tccal SIS m 461 20 12 2S 11 4 3 CoatrnJ* Tetal $12 493 461 20 12 2S 12 4 2 Findings on Smoking Tables 1 and 2 reveal the distribution of the lung eaitcer patients according to their biological characteristics -- age, sax, race, and the wsenriai similarity of the Batched control aoriea in respect to that characteristics. Tobacco wage by long cancer pa* tients and the control group k shown b Table 3. Here ooe may note that 484 (93 per cent) of the cases gave hie* lories of having smoked cigarettes; whereas only 394 (76 per cent) of the controls gsve a similar history. No such greater frequency of tobacco usage is other forms (pipe, cigar, chew, sad snuff) occurs imong the hmg cancer patients when compared with the eon* trol group. In feci, 68 of the control group used tobacco in a form other than cigarettes exclusively; whereas only IS of the lung cancer patients did to-- relative frequencies which are sot much Table 3--Tobacco Uoag* Derieg 30 Yean Prior to Seedy Reported by Loaf Caocoe Patieot* and CaotrcU Maaacrct Uamg Tehccca Tetal Tetal aat tmoking aigamicc Ne an el tobacco Tebecce ether thaa cigarettes, aoly Total waking eigsrcttec Ogwcttcs, ofliy Cigarette* and ether Adeae cemawea 46 6 4 2 40 31 9 Caeee Other Type* ef Cafeiaaau 472 22 IS 13 444 * 291 116 Tetal Sit 24 19 IS 4H 229 155 Ceotrelt Tetal $12 124 56 62 m 240 154 LUNG CANCEH VOL U Tr-- I Imnl W Qesrvtle 3oki Daria* 20 Yn Prior to Stagy tapecied Wy L*m* Cowcar Patients and Control 175 GpMW ^kad pvOcy Total None <* *12 or man Not neerM Com* Number Ptf emt SIS 100 M7 19 4 71 14 304 59 ao 15 10 1 Ceetrel* Number "KT 513 100 124 24 SO 10 IQS 199 38 22 4 It } different for the nouuacn of tobacco la the two aeries. ' Tliii suggestion of an effect by cig arette* only la conabtent with other in- vrstigsdons m the fidd. Soma rapport lot the hypothesis that dgurette smok ing aifeett the development of epithelial carcinoma of the long more than sds* uocimnotaa may be noted* Six out of 46 (13 per cent) of the earn of adenocarcinoma did not smoke cig arettes; whereas only 28 oat of 472 '<> per cent) of the patients with other >) pcs of carcinoma, described variously a> tquamooa, epithelial, ondifferea- tiatrd, did not smoke cigarettes. One commonly used measure of the amount of expoaare to cigarette smok ing, the average number of pecks smoked per day, appears in Table 4. Seventy-four per cent of all lung cancer patients 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. `Tirrams cigarette smoking'* (two or more packs per day) occurred sboost four times as commonly among the case series as among the control group. Other items which may indicate the mount of eigarette smoking include the age at which the individual began smoking, whether or not he smokes be fore breakfast, and whether or not be Hinhaks.'* Table 5 reveals that, by all ThU 5--At* *t fcfifuifaif Ostmi. Smoking, Smoking (Tahiti, and "Cigarette Coogk" Bepawed by Lang Center Patients and Cantenia Cinrcite e~nHag Quracttffetks Nok Caste Per etas Baaed ea Clserene Sreokan Oaly Par earn Breed on Tetel Number Cemrel* Par esat Baeed aa Cigarette Sawkan Oaly Tottl sit 100 SIS Total eieamte neokera 444 100 n 394 100 0**4* IS yean of age 146 34 32 116 29 Bcpi 15-24 m 59 55 243 62 Bnsa 25 yean ai age 32 7 4 35 9 "Inhale* 449 93 87 327 S3 "*eka More breakfast" 373 77 72 229 58 'Cavcttc eoogh" 304 42 39 112 28 PareaM Baaed tA 100 76 22 47 7 63 44 22 17* ITB, 19*4 AMERICA# JOURNAL OF PUBLIC HEALTH Table Estimated Piwalene* Rate* * of Lang Cww pr 100,000 Mala* W Selected Ayea aad Vm4m* Cigarette Smoktsy Hahita Nembef Le*i Caneae Coeirol Estimated Prevalence Rate* frontier Saeeked Daily t All Qaaa* Heavy tiiice Neaa Relative Pr*vtk*ee t Heavy AH Qwaa* tinea Paxketa seed SO-59 yean L Pell sad Hill 276 27S 94 42 7 13 6 2. Wynder iad Crahaa 258 210 117 47 4 2? 11 1 Sdewky. Gilliam, sad Cornfield 198 208 r 44 32 7 4 4 Present 215 213 102 46 6 17 7 Paliesu teed 60*69 yean L Doll tad HUl 197 199 137 63 0 ,* ,, 2. Vynder and Graham 117 160 138 70 5 29 IS 2. Sedowtky, Gillian. ad Cornfield 76 71 44 71 3 9 4 4. Present 168 169 433 73 17 25 5 twWwM mmOm i* IW MW W CmSM." 0w* Im MOM* tlMW I8i VrM mi CWi *W WiWi. CUttoM. mi Cm*ttot ka iW ton* *.>* QMUr mM twit, mw tot )mm Wr. to U tmmm M mW*< riwW m (Iimim M f*aa mi M|h finite it IWM mmlm <WMW m tort--II 1. 0W1 ta* HtU--l as. W Wan a <W a * na/rn* a Wrt L VrWtt --* Cwtiaw 1 W*m m * ilOMUt. 1 *WWW * tH iMmM: W 1. hlnii. *"1im mi C--lM--I *tm * I* W*mmmw t -- WW iMina a J* mmm k Tm )n--i Wr, yiautr MW WUr WMa <lpnm wi>! { ItWm riWwii to it* m>Wi Wt--y.Mt m| katt? iwWi/M mm MMatoni ^ (MtoW-Mt Mane MtniRu mm| mmmMw Own <aWlM to MW tw fad-fee mW M Im miw m wI'Imi W mm-- jar 4tri--4. BW1 mi mu-M Mttti S. VnM CrtoM n tr amI S. IWmW, CfUtoM. W CwlW rt m mmmt mi t pnM MatofM* am. of these criteria, the long cancer pa* tints smoked cigartttaa to a gTtater ex* teat than did the control group. Also, approximately two-fifths of the long cancer patients stated that they had had a "cigarette cough" usually antedating the onset of their ilioese by rainy yean; 120 said that they had had a cough for five years or more. The frequency of each "cigarette cough** was oniy about ooe*balf as great among the control group tod only 39 of the control pa* liests indicated that their cough had lasted five year* or more. Significance of Findings on Cigarette Smoking TTse data dearly 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, wU controlled studies; all indicate a positive correia* (ion between cigarette smoking and lung cancer, a correlation which increase* steadily with the amount of dgarette smoking. One can hardly escape the conclusion of Dolt and Hill4 that "smoking is a factor and an important factor in the production of carcinoma of the lung," and the more recent con* elusion of Doll,1* "The results amount, I believe, to proof that Booking is a cauv of bronchial carcinoma.** The cigarette smoker or prospective cigarette smoker may wish to know Uow 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 LUNG CANCER VOL 44 177 '.keiihood of lung cancer? Farther, .flux u that livelihood in sbaoiuta unaa? To eiawer these questions definitely would require that records of cigarette smoking for Urge namben of penous in the lung cancer age be atrembled. There persona would then be placed in categories with respect ta cigarette smoking, e.gt nonamokers, moderate smokers, and beery stokers. Finally they would be observed for w/Lcient length of time to determine the rote of lung cancer among the various .ategories of cigarette smokers and the noaunoken. (Such studies are now under way.) However, statistical devices have been developed for data such as those in the present investigation which, if one is willing to make certain assumptions, yield an answer to the question, how many times does cigarette smoking ia crease the likelihood of lung eaneer? Application of Cornfield's formula u-12 to tits 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 as great among smokers as among non* smokers, and from vevea to 27 times as great among heavy smokers as among nonsmokers. Similar ratios were found for the 60-49 age group. This formula involves the assumption that in so far as smoking history is concerned, the pa* tients are a representative sample of ell lung cancer cases sad the controls are a representative sample of all other per sona in the general population. Rndinps on Occupations Aa noted earlier, the records for lung cancer patient and controls showed all TaUa 7--Twemty per Mt haaple from Complete IiM eg OnepsUsaal Creeps ` ta Thick There Were u Lea* 5 Cem er S Cstrtreb Ewplsysd fee 4 Years er Mere OccepaUsa PmM Eaplayed ia Orcspstiea sc Least 5 Yetrs Ceas Ceatreis 006 Aethers, tditen, *d repsrters 081 Ship captaiat, wle\ pikes, ted eafjacm IQS Oerka, fCMsal sties 1S5 CiATwcn sad *eliciter* 180 Stli.iaim (a eeeseawrs m Vsitm sad waitresses, exevpt privste ftatty 266 Puliceetes ted deteerivw, pahlte awice 007 Aoiaui tad IWertack farmers 317 Ftrm heads, ia*l ttd ttvsaack 433 General veadwsrkiae secapatbes, aat dtewtos rlaiUsd S16 Ptiaisn, ocepl ceaatrsctiee sad msiataaaaae 524 Brick tad ummoomm sad til* tanas. 532 Coasuweitae secapsfises, set dwwfcms *-* 542 liicseiattvs Irenes 560 Atteedaau, Wile* nathae sad perktef tsu 583 Mcduaks tad rtpaimes, sot slawhers clamiied 7 < 2 5 7 14 6 6 10 I 5 $ 45 3 10 IS 9 8 I 11 4 10 5 $ 10 7 6 1 S * 9 16 m FF.fU l*St AMERICAN JOURNAL OF FULUC HEALTH TaUe --Occupation Croop* * In Which ihe Fr**f*rwr7 of X Y*mr Employment Amon* C***t Wa* *t Least Twice n Crest n Ammf Control* Onespotion Penas* V>npi7d ia Occapatuwi it Le*t 3 Yean Com* Central* 016 Eafincvn, <i*U ia Sleek clerk* 266 Policemen sad defective*, public ervice 4 Lumbermen, rafamea. sml weed ehappm 473 Machine tbep ad related eccepefteei, set almohua ritaaified $ alders and 6mm cutters 320 Occupations hi productiea ef petroleum m Corutradios machinal? epetatan, aet airewbera Homilcd 4 Brick and wimemaaam sod tile aettm S Brskcmea, railroad 570 Fires**, ether tboa peacaw Inam 573 Craacmm, derrkkistn. betstmea, and dtevclaco 375 Driller*, estrsetleo ad miacral* sod eooatrocuoo S 7 6 11 1 10 s 7 5 10 11 15 7 1 3 3 5 3 1 2 3 1 S 3 6 2 Or*e*eUm Hwti< w*t** m (* Pu.t--, tt flemiUiM T*t *.). a Cl U. S. I--Iiiwi W*im. m*. im**m mb i--mum* I* ** tee mm m Wo 1 *00 I fan m M t wlmM, . occupations followed tod their dure* lions in yean. A listing was prepared of the occupations pursocd by at least five patients or controls for five yean or more This luting revealed 81 occupotions in this arbitrary frequency-sodduration category. Table ? presents a random somple of these occupations and the number of patients and controls who st 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 workad as authors, editors, or reporters (occu pation) for five yesn or more, and among the 518 controls, nine had been similarly engaged. Relative frequencies of occupation would appear to !tnvc the same logical significanca as such fre quencies of cigarette smoking. The lat ter is, of course, much more common among both ease and control groups than is any single occupation. Hence, the numbers pertaining to any one oc cupation would ba less impressive than in the case of cigarette smoking. How ever, the frequency with which the lung cancer pttients had pnrsued 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 eommon exposures. For ex LUNG CANCER VOL 44 179 ample, one occupational group, number 530 (plumbers, ps fitters, tod steam fiticn) showed 16 cues tad 10 controls with t five-fear employment history. Elimination of these 26 individual records revealed thst substantially all ihe difference between case and control series waa dut to the steam fitters who Ud s heavy exposure to asbestos. It ,u itM noted that other types of work iavolving ubestos occurred more fre quently in the employment history of cases than among the employment hi* lury of controls. Thus, a new category, including steam fitters* asbestos workers, and boilermakers- all involving expotore 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 tigoificaat exposures. Although am bers in each of the categoric* are small, the differences between ease* and con trols appear to implicate the occupations listed. It is of interest to note that tcveral of those with the meet striking differences involve exposure to metallic particles and fumes and product* of metallic combustion. This observation lends to corroborate tbe suggestion of Wynder and Graham u that "hot metal* occupations may be involved in lung cancer. In recent data of Doll10 the only occupation with an important excess in the cancer group was thst directly con cerned with ihe production of gas. Little or no support was found indicating that other occupations suffer special risks. However, Doll's study wu based upon experience in England where tbe em ployment pattern differs from that in the United States, especially California. Also, Doll used an occupation code of only 76 enN-gorirs which may hare been too coarse to reveal the differences found in the present investigation where a code of 367 categories was used and analysts carried to subgroupingt of tlwfe. It may be noted that 77 persona with lung cancer had an exposure of more than five year* to suspect occupation* (unduplkatcd count in seven occupa tion groups) according to the data in Table 9. This number represents 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*Me -Gwea uH Caatrsl* Employed for it Lmm S Year* is Silwtd Qnspel-- Group* * Oi--pettso 1. '-VaJcr toil thrtt acta) rekm dow* wvldiof 1 Siftn fium, haiheonfcm, and abc*te worker* i Electric btides mm *pernor* acul ladsatry < Occupation* ia iSe extractioe ef Ired, liae. and copper ers S. Marine m-inem. firwwro. nil***. and wiam < (.'(Mka, -TwniMtTui (eaatsdiot esnacry cook*) Pereoaa Employed is Occapatie* at lrc*t S Yrsrs Ca*a Control* 14 2 10 l S1 91 12 $ 22 22 35 21 OTpMtaMi iiw* 180 ra. 1961 AMKMCAiN JOURNAL OK PUBLIC HEALTH TaWa 10--Example of Adjnatmmt far Smoking Applied to a*d Sbcet Met/l Torkers Doing V'tUiag Moot Packages si Cigarettes Smoked per Div <S >4- t- 2 er Not rm more corded Total All cases ted controls, auk* L Cases 22 X Cootrols no 1 Total 4. Proportioa pi 132 ease* among total cases aad eonrroU 0.16? Teiders aad sheet metal wwkars doing voiding. mole 5. Cases 0 L Controls 7. Total 8. Exported auxuher 1 1 W woldor esses t 0.167 16 69 296 80 45 105 193 22 61 174 489 102 0.26S 0.896 0.605 0.783 02 00 02 11 1 12 1 0 1 0.0 0.792 7.860 0.783 10 493 18 493 21 986 0.3S7 0 14 03 0 16 0.0 9.002 mo-Im pm mi 1 M 14 eMn s * s 4.SIS It 14 I: Ur th* mithi -- m 14 41?. 41W)- luimMilh OmIiM M It pm U Mto t nUm to IM ailm MUM (Um fc 4 X tta No- ?l. t JfaiS. A. liwuul T(*iM mS r--lw. M Ywii 1M Wilor. IKS. RMi TUi m M *ffttoO I *13 MM mMM pan Mm* to tMb *. MaMa Mm rntm* tSr MtMUa *1 uwml ii|iiliiiii m toe tf i mM Mn at ib* 44 pat na toM t mmmiwm TW tnnf "Mea tu*M M W*J. ha <t too * 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 an occupation operates as a factor distinct from cigarette smoking in relation to lung cancer (Table 10). Tbe group of steam fitters, boilermakers, and asbestos workers lias on the border* line of statistical significance when the .effect of cigarette smoking U controlled. In the other occupational groups the numlters are such that the differences might arise from chaoce 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, sad 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* mg tgt-sex group in the general population. One may thus determine LUNC CANCER VOL a 181 how bing in particular occupational -roup affects the chances of developing Ls cancer and likewise how cigarette .poking modifies these chance*. Conclusion The data in this study constitute still muiK-r link in the chain of evidence connecting lung cancer with cigarette 'lio'kjllg, evidence which the New Eng* IjiiJ Journal of Medicine notes to be >o ftmng as la be considered proof iiiiin tlw everyday meaning of the word." 14 It is time for those concerned kith health education; and with the ethic* of advertising, at least in health and medical journals, to take note. Further investigation should seek the .-tact component of cigarette smoko-- tar, arsenic, or other--which is respon* mLJc. The data also suggest that several <i upatioas (Table 9), m addition to thuse previously identified as having an biological relationship, may be involved in the development of long cancer. Tl.ve occupations should now be in* icnsively studied to determine to whet extent persona engaged in them suffer a special risk of lung cancer. Them* after, if an etiological relationship is < karly established, the precise exposure and roecltamstn responsible should be identified in order that protective meas ures may be introduced. ttiXKOCXS t. Ota. u. l. omi. a., im i. l. >t* t**< * S*Ui>h t !*,. ln. 1. Cimm 1:1. INI I. JmIwvS. K. Ifc*r. L A.. S*ll4>4. C. P.. t*4 Daif**. S. Tomii Jwk;, u 4J CiiuixirU Trt i \t Piw*. Cm<" lra.nl ltl& J. Vf*Srr. C. 1*. *+4 C,m*. C. a. TAk< SmS* >< m P*ubl* TM*i*tn Tttttr la It-- Gwaiat A V.il-* k t*V Prv**a C4M*. )~k.M-A. IUJ5S-8A. ISM. OWL 1.. m4 Hill. A. L A S<a4t W >k* AMIUMS W Camt W tk Um- *. U. 1. J mV-USt. 1*8. S. Lr,*. M. L. CaUH.i*. ftm m4 O-HwaUt. p. , Ca*t* tm4 TakMta 5ai>a- A P<ta<MfT pm*. ]A *A !:*-m, ISM. *. lMf, V. C Taa^n *#4 AUM rwu--i s**MM*f4. m.t twm. ho. 7. IimiiH. 0.. Imh. .. iM Srkwari, . 9fe SeftksMkrrf Pel Cukaul--aa U ><k,Sn la IwW |*ainm L--OMlMi"). Zxatftf. f. InUmuP OiMS m. ms. $. UaakJa. V.. -4 Cr.ti,IMk T. Cm W ita UaiaiT SrMia * :ka CaM*4 HaakS Rv*. UiUlWUn. ISM. Pfc. * Q^m. S. M. hiiaaaMii JlaiUaflul !mt W *--,! Uwwlat la UM Cm** Umh )), isn. IS. CM. t. IraaiHil Cawta--ai WiIhh aa4 Ail aiaay. P ( M P*k Jl. tw. U. J. 121*87. MS MS. ISIS. 11. CwaSUt J. A U,<U4 W (Mfiniin M*m bwa CUatraJ D*. AaaituiMa i Cjtnr 4 M* Uas. SfW. m4 Cm. J. Kat. Cwtr tak. llilSM-Un. tl. IS. SM--Mf. D.. CiOlaai. A, aaS CaaaiaU. J. TU I AmMmm Saii'wa !* aa4 Ca#> tkill at Ik, Uaf. 1V^ ISilST'IUS. ISO. 11. Siakr. L U. u4 Sfahak, C. a. Ctial*(i Pavtart W Smatfelaaaaa C<r*i**a <r<ik SmcmI >,Imiiw k MwiimI Cakawi*,-. S*a*t at Sir Pfr*A Cava. 4h. !*--. t Omt. Mai. 4U2I. Itil. It. UkartaL Caaan W tka Ua. Ma alaaA I. Uak. ttSMl-iM. ita. Journo! 25 Years Ago Addendum to the January, 19S4 "25 ^etrs Ago." In addition to the articles -n die ronuunn cold mentioned last month, the 19^9 Jwurnst (p. 4-191 drsetibes an eight-page booklet "That Mean Cold,' by prount-dsy apsociaie editor of the Journal, Raymond S. Patterson. It was reportedly Uis first production as director of health education for the John Hancock Mutual Life Insurance Company, the January issue (p. 9t) having reported his appointment as director of health 'duvuiion. Life Conservation Service of that company. Dr. Patterson had already k*T,` the author of AJ.P.H.'s "Annotated Public Health Bibliography ' for teversi . ars, it haring first appeared under his bydine in March. 1926.