Total fluid and specific beverage intake and risk of renal cell carcinoma in Canada

Background: Intake of total fluids and specific beverages may be associated with the risk of renal cell carcinoma (RCC) through a diluting effect of carcinogens. However, total fluid consumption and RCC risk has not received sufficient examination. In this study, we assessed the roles of total fluid intake and type of beverage intake in the risk of RCC. Methods: Mailed questionnaires were completed by 1138 newly diagnosed, histologically confirmed RCC cases and 5039 population controls between 1994 and 1997 in 8 Canadian provinces. Data collection included information on socio-economic status, physical activity, smoking habits, alcoholic and non-alcoholic beverage use, diet, residential history and occupational history. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived through unconditional logistic regression. Results: Higher total fluid intake was associated with risk of RCC; the OR for the highest versus the lowest quartile was 1.49 (95% CI 1.20–1.85). Intake of total juices and coffee was also related to the risk of RCC; for the highest versus the lowest quartile, the ORs were 1.53 (95% CI 1.18–1.99) and 1.33 (95% CI 1.07–1.66), respectively. These positive associations were stronger in men, but not in women. Higher coffee intake was more strongly associated with RCC in normal weight subjects. In contrast, total intake of alcohol was inversely associated with the risk of RCC. Intake of tap water (not in coffee or tea), bottled water, tea, soft drinks and milk was not related to RCC. Conclusions: The risk of RCC for higher intake of total fluids, coffee and juices might involve gender differences.