Are coffee, tea, and total fluid consumption associated with bladder cancer risk? Results from the Netherlands Cohort Study

Objectives: Coffee, tea, and fluid consumption have been thought to influen ce bladder cancer incidence. In a large prospective study, these associatio ns were investigated. Methods: In 1986, cohort members (55-69 years) completed a questionnaire on cancer risk factors. Follow-up was established by linkage to cancer regist ries until 1992. The multivariable case-cohort analysis was based on 569 bl adder cancer cases and 3123 subcohort members. Results: The incidence rate ratios (RR) for men consuming <2 cups of coffee /day was 0.89 (95% CI 0.51-1.5) using the median consumption category (4-<5 cups/day) as reference. This RR increased to 1.3 (95% CI 0.94-1.9) for men consuming greater than or equal to7 cups/day, although no clear dose-respo nse association was found. The RRs decreased from 1.2 (95% CI 0.56-2.7) for women consuming <2 cups of coffee/day to 0.36 (95% CI 0.18-0.72) for women consuming greater than or equal to5 cups/day compared to the median consum ption category (3-<4 cups/day). Men and women who abstained from drinking t ea had a RR of 1.3 (95% CI 0.97-1.8) compared to those consuming 2-<3 cups of tea per day (median consumption category). The RR for men and women comp aring highest to lowest quintile of total fluid consumption was 0.87 (95% C I 0.63-1.2). Conclusion: The data suggest a possible positive association between coffee consumption and bladder cancer risk in men and a probable inverse associat ion in women. Tea consumption was inversely associated with bladder cancer. Total fluid consumption did not appear to be associated with bladder cance r.