The Copenhagen case-control study of bladder cancer. II. Effect of coffee and other beverages.

During the years 1979-1981 a population-based case-control study of bladder cancer including papilloma was performed in greater Copenhagen. A total of 371 patients (280 males; 91 females), and a comparable age- and sex-stratified group of 771 controls (577 males; 194 females) remained for logistic regression analysis. Controls were selected at random from the general population of the study area. All persons were questioned about their drinking habits with respect to coffee, tea and other beverages, as well as their exposure to a number of known or suspected risk factors for bladder cancer. After adjustment for tobacco smoking, the relative risk of bladder cancer in relation to coffee drinking was not statistically significant among either men or women. A significant association was found between bladder cancer and tea drinking among men, but with no regular trend for increasing consumption. An association was found between risk of bladder cancer and both total daily liquid intake and non-cola soft drinks. This population-based case-control study provides no evidence of an isolated influence of coffee drinking or caffeine intake on bladder cancer risk.