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A p 1i9aE Elsevier Science Publishers B.V. (Biomedical Division) Smokin=and health 1'9D7.N1. Aoki eCal;,editors 279.., PASSIVE SMOKINC I5' A RISK' FAGTOR FOR LUNG CAIVCER' IN NEVER SMOKINO' WC?MEN'' . IN HONGI KONC TAII H I'!G ' LAt4, XAR KEUNG CtiENG.,: Department of' Cbmmunity Medicine, Glniversity of:.Hon'g, Kong, Li; Shu Fan Building,, 5 Sassoon Road, Hong.Xong,. ..: : INTR©DfOCTION' rates among men are not particUlarly. higto;, in-.Hbng Xongw'- However,:. the. rates in women are among thei bighcst ; in `the w©rld~ Four, case :control''" aa,l~ignant neoplasms in both . sexes: On, a world' scale;;• lung caricer. ,deat In Hong,Kong, Aung cancer is,;the, leading,.cause,of:death due to studies have been carried out in :Hong~- .Kongi"to investigate the' risk . ; . ~ ' ft f l in, prt acorsorungi cancer women xar:.uy•.,smng: an. passive ? ilarlokid smoking. They are reviewed as follows: L. 1976-19'77r S71UIDk' The first major stud,y, on risk factors -for.lung cancer' was a case . c . , .. . . . , : ses y In females the RR for smoking was onl 27 51! 3 '48 44'41 o' f the a found to, be a major risk factor .1 n males with• a. relative risk (R3I) of .: 204 male andi 1189 female hospital.::orthopaeddc-ipatients: - Snok'img 'was control' study on 208 male and 18Jt female :patients. ,. ~Tfie controls • were =':~ were non-smokers whose tumours, were predaninantly~ adenocarcinomas The role of passive smoking was,,studied', ty•'simpl~y asking the question !_- of •Are you exposed to the tot~a!ccm;smoke ,of~ o;thers at home or' at .work?'". For non-smoking women, 40.5%of the cases and 47.5% of the controls had~.` passive sm'oking,. The RR'for'passive smokin'g-was.8.75~(P=0.38).2' slsuctured questionnaire. e RR:for ever.snioking.was:7.77 ti;44.0t of&J; fema,Ue controls matched' forr age:uere. interviewed-'.in dept'h dsang-a`sem In the second case control' stiddy,_ 200 female,'~cases•and .2i00i.district IIi. 1981-1!9'83 STUDY the cases had never smoked. ' hysband was 1.4'9 (P-0L10'.3;. controls had smoking husband. The RR-for passive.smoking'dwe to'smokin yaong, the never-smoked wi'vesr'-. 6'1.4'1 of ttie cases •and 5'1.81 of the_ u,cluded. A standardized questionnaire rras':uSed: fbc :;intervieming.,: The''~ studies, only histologically and,(or ~cytologicaily.confirmed _cases_ were;, <. cpntro,ls from hospital orthopaedi'c gat3ents, 't1n13'ke the"previous two The third case control stu(*.. i'ncluded:163 female'._cases: and'-185 female IIT. 1981-1984 STUDY vas'46.0t. ~~• , !tR for smoking was 4'.1!2 The prop4raion of cases.whol we,re'non-smokers :_?. The role of pas'$i've smokillg was,. skUdied'oniy on'''tne ade'nocarcfnema.. ease&; For non-smoking women.'61i:7t bf ..`t}oe adeniocarciiooina cases and

R ~,- due to smoking husband.' The' 4% of' the controls hadi'passive.'smoking 44 . . , RR for passive.smoking was.•2.01.('P<0.05). Analysis..was also carried out by the site of the tumour. For, centrally sitedl tumour,, the ttR for passive smoking was 1.61 (P>0.05). For peripheral tumour, the RR was 2.64 (P<0,05I) .4 280 IV. 1983-1'9i86 STUDY This was the largest case control study on lung cancer in women in Hong Kong. -A standardized!:s!tructvred, questionnaire was designed for interviewing. All the ,cases vere conf i;rmed ` pathologically. . They were.. compared with 445 feinale healthy neighbourhoodlcontrols.matched.for age.:.- ,._: .... ... The RR of ever smoking was=3.81.:, 45'.51 of the,cases :were never, smokers. For mever smoking.women, 57.8% of the cases and 4S.4t,of-t3ie controls. had passive smoki'ngi diue to a smoking husband. TheItR for=,•passive smokings was 1.65` (P<0'.01, 95% C. L. w1.16, 2,35) . When broken down byscelili;type,::the propor'tion of never smokers of 62.4&' was the highest`;;in arlenocarcinoma and it was,.oniy in this cell ;-.. . typelthat the.:RR for passive smoking was statistllcally.signi,filcant - (RRp1.87, P<0.01, 95I~ ,C I.*1 23,;,2 85) :: Signdf icant :trends for RR _with amount smoked daily by husband were observedl.for:.all'ceil.types combined : andl for adenocarcinioi'na only.: TABLE I SUMMARY ' OF RESLlbTS` ON PASS3'WE' SMOKING 11Nf0'NG' NON-SMOKING "IEN' IN 4 CASE ~.h"~24i0,/353 „ 191/402,,. 223 •. 225 204 1186; : P - value 0.004`• * Zfie study by' Lam,.;W1C Included only adenocarcinomai.whereas the other three studies :includad-;_al1 cell types. . **'Summary,:.relative;ri'sk by,;;Mantel Haenszel's method: ODWI'ROb STLiDIES IN:-IK)NG KOtJG' ::.;: Passive::,.No,passive smokingr;'; sinoking. 1976-1977 _ ,,34/66 ,:.50,/7'3:.; Chan & Fung, 1983 " '. 1!9'81-1983 54/71 '. ,34;/66.. Koo et: a1', 1985 ; 1981-1984° . 37/64 .•23/80 :,. Lam WK, 1i985 ~.3 > •. 1983-1986 ~ ~~~f15%152~~ ~ 84~1'83 sv Lam TH et~al, Total no. ` of cases. & Rel.ative cdntrols-. risk

, SUMMARY OF RESULTS ON PASSIVE SMOKING Table I,shows the summary of results of the above four studies. Apart stat st ca s1gn icance was reached in the recent two. The Mantel- ~~ , froca ene eiisr.Laese scuoy in wnsen. only one.simplc`ques'tion.,was asked t*ti about pas'sdve smoking, they all showed a RR greater than un4ty: s summary RR was 1.4 Naensze (B<8.01, 95S C.I.=1.12, 1.83). In a review of epidemiological and other evidence on passive smoking and lung cancer, Blot and Fraumeni estimated a,3ieR excess risk6 while Kaild et al calculated a relative risk of1.35 by pooling the results of • ' 1`. _ . .. - - ten case control studies and three prospective studies. The svmmary RR of the four case control studies in Hong.Kong~as close.to-these estimates. Because the local prevalence ofsmoking, among women was low (4.11),g the influence by misclassificatioriibias iaouldir'tae much less than ~ in western countries and could not account for` the~rellatively hiigh :RR »y .. Z+h~e results in Hong Kong therefore stronglyi>,;'sticggest tha~t:.passive:sinokiia, is a risk.factor for lung eancer,innever smoking-Chi'niese women. , ACKNA+ILEDCEMENT r , We thank the International Deyelolnent Researchentre•and the..: ~ , Medicai Faculty Research Grant. Fand) for •financinl the~-rescarch- project-. 4 University of Hong Kong (Committee on.Research:,and Conference Grant and .• ,. ,.. .,, : - . -~ .. , . :J.. .: ~~..... Thanks are also due to Dr. -DW;.Han and Dr.,;:Reith.•A-rnold ..for their... support, to Roche Asian Research''Foundation'.for Msponsoring oyr ~.f . . presentation of the paper and to:Mr. Richard..Peto for his comments.- REF'ERENCES 1,. Chan WC, Colbourne PLT, Fung SC, Ho HC -(1979),Br J Cancer.39:182-1192: 2'. than WC, Fung SC (1982) In:. Grunrimann E:(ed)-~,.~Cancet Campaign, Vol Cancer Epidemiology, Fischer Verlag,, Stuittgart•.and New.York, pp`199~ 281 3. Koo LC, Ho JiHC, Lee N(1!985) Int J Cancer.35s149-155 4. LamiWK (1985) A clinical and epidemiol©gicalstudy of carcinioma of lung in H©ng, Kong. M. Ds Thesis, University of: Horog, Rong, : Hong Kongi;..: 5. Lam TH, Kungi ITM, Wong CM,. Lam WK, Kleevens •JWL, Saw' D, Hsu C, Seneviratne S, Lam SY, Lo KK, Chan WC`: (1987')"•: Br J Cancer 56:67'3-678 6. Blot WJ, Fraumeni JF Jr (1986) J, Natl.Can'ccr:Inst 77:99'3-1i0iei0 7, Wald W, Nanchahali K, Thompson SG,,;.Cuckle°H5 (,1986) 'Br Med J 293'~' 1217-1222' ~ . _ .. , Hong Kong Census and Statistics Departmenf (1985)? SpeicialTopics: Report III, Social Data,Collectedby thetGeneral RouseholdSurve . . . c t t -• . . tt. twlK•.,. t Government Printer, - Horg ..Kong 1.. , . .. ...i:;i/iV.V*.;Y~'1:~\Y`~ ..