Associations of tea and coffee consumption with prostate cancer risk.

PURPOSE: Tea and coffee contain bioactive compounds and both beverages have recently been associated with a reduced risk of prostate cancer (PCa).
METHODS: We studied associations of tea and coffee consumption with PCa risk in a population-based case-control study from King County, Washington, USA. Prostate cancer cases were diagnosed in 2002-2005 and matched to controls by 5-year age groups. Logistic regression was used to generate odds ratios (ORs) and 95 % confidence intervals (CIs).
RESULTS: Among controls, 19 and 58 % consumed at least one cup per day of tea and coffee, respectively. The analysis of tea included 892 cases and 863 controls, and tea consumption was associated with a reduced overall PCa risk with an adjusted OR of 0.63 (95 % CI: 0.45, 0.90; P for trend = 0.02) for men in the highest compared to lowest category of tea intake (≥2 cups/day vs. ≤1 cup/week). Risk estimates did not vary substantially by Gleason grade or disease stage. Coffee consumption was not associated with risk of overall PCa or PCa in subgroups defined by tumor grade or stage.
CONCLUSIONS: Our results contribute further evidence that tea consumption may be a modifiable exposure that reduces PCa risk.