Cigarette smoking, alcohol use, and colorectal adenoma in Japanese men andwomen

PURPOSE: The aim of this study was to examine the relationships between smo king and alcohol use and risk of colorectal adenoma. METHODS: Information a bout smoking, alcohol use, and other lifestyle variables mere obtained pros pectively from 14,427 male and 17,125 female residents in a city of Gifu Pr efecture, Japan, by a self-administered questionnaire in September, 1992. C olorectal adenomas mere newly diagnosed in 181 men and 78 women in this coh ort between January, 1993 and December, 1995 by colonoscopic examination at two major hospitals of the city. Gender-specific and site-specific relativ e risks and 95 percent confidence intervals adjusted for age and for age pl us other potential confounding factors were calculated by using logistic re gression models. RESULTS: Thirty or more years of smoking was significantly associated with risk: of adenoma in general compared with never having smo ked in both men and women (relative risk, 1.60; 95 percent confidence inter val, 1.02-2.62 and relative risk, 4.54; 95 per cent confidence interval, 2. 04-9.08, respectively). Effect of smoking was stronger in the proximal colo n. After adjusting for age and carbohydrate intake, total alcohol intake wa s not associated with risk of adenoma in any site in the colon in men. Sake drinkers were at significantly increased risk of adenoma in general, but t he dose-response relationship was not statistically significant. Risk of ad enoma in the rectum was not significantly increased for those who consumed >30.3 g/day of ethanol (relative risk, 5.7). CONCLUSION: These data suggest that smoking is a risk factor of adenoma in Japanese men and women. The ro le of alcohol, however, is less clear.