Beverage use, fluid intake and renal cell carcinoma: Results from a case-control study

Background: The effects of various beverages on the incidence of renal cell carcinoma (RCC) remain inconclusive, while recent studies have suspected protective effects for high fluid intake. This study evaluates the role of common beverages and fluid intake using a case-control design. Methods: Incident cases (n = 335) were identified from Florida hospital records and the state cancer registry, and population controls (n = 337) were identified from random-digit dialing. Interviews assessed one-year intake of coffee, tea, soda, juice, milk, beer and wine. Odds ratios and 95% confidence intervals were calculated using logistic regression, controlled for age, sex, race, smoking, and BMI. Results: A significant protective trend was found for coffee consumption (all types) when measured in lifetime cup-years (Wald χ2 = 5.603, p = 0.018). Drinking four cups of coffee per day for approximately 40 years significantly reduced risk for RCC (OR: 0.35; 95% CI: 0.20, 0.62), an association that was stronger among men and whites. Controls were more likely than cases to consume wine once a week or more, although this association was only marginally significant among whites (OR: 0.68; 95% CI: 0.45, 1.02). Consuming 48 ounces or more of fluid per day was associated with reduced risk only among men (OR: 0.63; 95% CI: 0.39, 1.00). No associations were found for tea or diet sodas. Conclusion: Heavy coffee consumption and overall fluid intake may reduce risk for RCC by decreasing the concentration of carcinogens in contact with renal cells. Gender-specific differences in these associations warrant further study.