Fluid consumption and the risk of bladder cancer: results of a multicenter case-control study.

A number of studies suggest a relation between fluid consumption and the risk of bladder cancer but results are contradictory. Different theories involving the quantity or the type of fluid consumed have been put forward to explain these relations but mechanisms remain unclear. We conducted a multicenter case-control study in several hospitals in France including 765 cases and 765 matched controls. Information collected by face-to-face interview included quantity and type of beverages consumed from the age of 18 until age at diagnosis, as well as smoking habits. Among men, we observed a slight non-significant increased risk of bladder cancer associated with total fluid intake, irrespectively of tobacco use. This was essentially due to intake of non-alcoholic drinks, coffee and bottled juice or water. Relative risks greater than 1 were observed in relation with coffee consumption. On the other hand, alcohol consumption, especially wine, was associated with relative risks less than unity. No relation could be identified between bladder cancer risk and fluid consumption among women. Our results do not support an association between total fluid consumption and bladder cancer risk. The role of the different types of fluid consumed, confounding factors and bias in the present analysis are discussed.