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

Abstract

Coffee, tea, and fluid consumption have been thought to influence bladder cancer incidence. In a large prospective study, these associations were investigated. In 1986, cohort members (55-69 years) completed a questionnaire on cancer risk factors. Follow-up was established by linkage to cancer registries until 1992. The multivariable case-cohort analysis was based on 569 bladder cancer cases and 3,123 subcohort members. 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 >7 cups/day, although no clear dose response 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 >5 cups/day compared to the median consumption category (3-<4 cups/day). Men and women who abstained from drinking tea had a RR of 1.3 (95% Cl 0.97-1.8) compared to those consuming 2-<3 cups of tea per day (median consumption category). The RR for men and women comparing highest to lowest quintile of total fluid consumption was 0.87 (95% CI 0.63 1.2). The data suggest a possible positive association between coffee consumption and bladder cancer risk in men and a probable inverse association in women. Tea consumption was inversely associated with bladder cancer. Total fluid consumption did not appear to be associated with bladder cancer.