Total fluid intake and use of individual beverages and risk of renal cell cancer in two large cohorts.

Moderate alcohol consumption has been inversely associated with risk of renal cell cancer in recent prospective studies, and increased total fluid intake has been hypothesized to be a possible mechanism. We prospectively examined the associations between total fluid and beverage intakes and risk of renal cell cancer. Among 88,759 women followed for 20 years in the Nurses' Health Study, and 47,828 men followed for 14 years in the Health Professionals Follow-up Study, we documented 248 incident cases of renal cell cancer. We assessed consumption of beverages every 2 to 4 years using a validated semiquantitative food frequency questionnaire, and total fluid intake was derived from the frequency of consumption of 18 to 22 beverage items. Cox proportional hazards regression was used to estimate study-specific multivariate relative risks (RR), which were pooled using a random-effects model. We found no association between total fluid intake and risk of renal cell cancer; the pooled multivariate RR for the highest quartile versus the lowest was 0.99 (95% confidence interval, 0.63-1.55; P, test for trend = 0.78). Alcohol intake was marginally inversely associated with renal cell cancer risk; compared with nondrinkers, the pooled multivariate RR for > or = 15 g/d was 0.66 (95% confidence interval, 0.43-1.00; P, test for trend = 0.07). We did not find clear associations between intakes of coffee, tea, milk, juice, soda, punch, and water and risk of renal cell cancer. Our data suggest an inverse association between alcohol intake and risk of renal cell cancer, but do not support the hypothesis that greater total fluid intake reduces the risk of renal cell cancer.