Foods and beverages in relation to urothelial cancer: case-control study in Japan.

Abstract

The roles of several foods and beverages in the development of bladder cancer remain unclear. We undertook a hospital-based case-control study at Aichi Cancer Center Hospital, Japan. Subjects included 124 men and women (bladder cancer cases) with newly diagnosed cancers of the renal pelvis (n = 5), ureter (n = 6) or bladder (n = 113) and 620 age- and sex-matched, cancer-free outpatients (controls) presenting at the hospital in the period from 1994 to 2000. Smoking-adjusted odds ratios (OR) were estimated to assess the strength of associations between self-reported intake of foods or drinks and bladder cancer risk, using conditional logistic models. We found a decreased risk in relation to frequent intake of green-yellow vegetables; the OR for the highest intake score compared with the lowest was 0.54 (95% confidence interval [CI] 0.29-0.99). The OR for carrot intake of >/=5 times/week compared with </=1-3 times/month was 0.41 (95% CI 0.16-1.01) and a decreasing risk with increasing consumption of green vegetables was also detected (P for trend = 0.063). Inverse associations between black tea, eggs and meat and risk were also suggested, whereas moderate drinkers of green tea (5-9 cups/day) showed an elevated risk. Coffee and milk consumption did not appear to exert any influence. Those with an increased risk of bladder cancer, such as smokers, may benefit from increasing their consumption of green-yellow vegetables.