Tea and other beverage consumption and prostate cancer risk: a Canadian retrospective cohort study.

Using participants in the 1970-1972 Nutrition Canada Survey (NCS), a retrospective cohort study was conducted to assess the relationship between tea, as well as coffee, cola and alcohol, and the risk of developing prostate cancer. The mortality and cancer experience of male NCS participants aged 50-84 years was determined up to 31 December 1993. Among the 3400 survey participants included in the study, 145 developed prostate cancer. No association was observed between tea (predominantly black tea) intake and prostate cancer. Subjects who drank more than 500 ml of tea per day experienced virtually the same risk as those who reported no tea consumption (rate ratio (RR) 1.02, 95% confidence interval (CI) 0.62-1.65). Compared to those who reported no coffee drinking, men who averaged more than 250-ml per day experienced a 40% increase in risk (95% CI 0.84-2.32). Cola consumption was not associated with an increased risk of prostate cancer. Total alcohol consumption was not related to subsequent development of prostate cancer, although very moderate consumption of wine (< 10 g per day), relative to no consumption, showed an RR of 1.48 (95% CI 1.05-2.09). These data do not support an association between consumption of tea and prostate cancer risk.