Environmental tobacco smoke in relation to bladder cancer risk--the Shanghai bladder cancer study [corrected].
BACKGROUND
Environmental tobacco smoke (ETS) contains tobacco carcinogens. Hepatic cytochrome P450 (CYP) 1A2 and N-acetyltransferase (NAT2) are important isoenzymes in activation and detoxification, respectively, of tobacco carcinogens. Data on ETS and bladder cancer risk are sparse.


METHODS
We examined the effects of ETS alone and combined with NAT2/CYP1A2 on bladder cancer risk among lifelong-nonsmokers in a case-control study involving 195 patients and 261 controls in Shanghai, China. A comprehensive history of ETS exposure was determined through in-person interviews while CYP1A2 and NAT2 phenotypes by a caffeine-based urinary assay.


RESULTS
ETS exposure was related to an overall statistically nonsignificant 38% increased bladder cancer risk. The risk increased with increasing number of cigarettes smoked by household members or number of hours per day at workplace where coworkers smoked. Compared with no ETS exposure, subjects living with smoking parents during childhood had an OR of 2.43 (95% CI = 0.99-5.96) for bladder cancer. When all ETS sources were combined, the risk increased with increasing total ETS score (P(trend) = 0.03). The OR for high versus nil ETS exposure was 3.00 (95% CI = 1.24-7.26). The increased risk with ETS was mainly seen among individuals possessing a CYP1A2 high efficiency and/or a NAT2 slow acetylation phenotype (P(trend) = 0.04).


CONCLUSIONS
ETS was associated with an increased bladder cancer risk for lifelong-nonsmokers. The association was stronger for people possessing the at-risk phenotypes of CYP1A2 and/or NAT2.


CONCLUSIONS
Reducing exposure to ETS for children and genetically more susceptible individuals could be more effective for bladder cancer prevention.
Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Li
L
Tao
Yong-Bing
YB
Xiang
Renwei
R
Wang
Heather H
HH
Nelson
Yu-Tang
YT
Gao
Kenneth K
KK
Chan
Mimi C
MC
Yu
Jian-Min
JM
Yuan
D001191:Arylamine N-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002681:China; D019388:Cytochrome P-450 CYP1A2 / Q000235:genetics / Q000378:metabolism; D004781:Environmental Exposure / Q000009:adverse effects*; D004785:Environmental Pollutants / Q000009:adverse effects; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D012307:Risk Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D001749:Urinary Bladder Neoplasms / Q000201:enzymology* / Q000453:epidemiology* / Q000235:genetics
D004785:Environmental Pollutants; D014028:Tobacco Smoke Pollution; C504573:CYP1A2 protein, human; D019388:Cytochrome P-450 CYP1A2; D001191:Arylamine N-Acetyltransferase; C478900:NAT2 protein, human