Fluid intake and incidence of renal cell carcinoma in UK women

Background:It has been suggested that the apparent protective effect of alcohol intake on renal cell carcinoma may be due to the diluting effect of carcinogens by a high total fluid intake. We assessed the association between intakes of total fluids and of specific beverages on the risk of renal cell carcinoma in a large prospective cohort of UK women.Methods:Information on beverage consumption was obtained from a questionnaire sent 3 years after recruitment into the Million Women Study. Cox proportional hazards models were used to estimate relative risks (RRs) and 95% confidence intervals (CIs) for renal cell carcinoma associated with beverage consumption adjusted for age, region of residence, socioeconomic status, smoking, and body mass index.Results:After an average of 5.2 years of follow-up, 588 cases of renal cell carcinoma were identified among 779 369 women. While alcohol intake was associated with a reduced risk of renal cell carcinoma (RR for 2 vs 1 drink per day: 0.76; 95% CI: 0.61-0.96; P for trend0.02), there was no association with total fluid intake (RR for 12 vs 7 drinks per day: 1.15; 95% CI: 0.91-1.45; P for trend0.3) or with intakes of specific beverages.Conclusions:The apparent protective effect of alcohol on the risk of renal cell carcinoma is unlikely to be related to a high fluid intake.