Coffee consumption and risk of prostate cancer: a meta-analysis of prospective cohort studies.

Observational studies and animal evidence suggest an association between coffee consumption and the risk of prostate cancer. However, the results are inconsistent. We evaluated the association by conducting a meta-analysis of prospective cohort studies. PubMed and Embase were searched through June 2013 to identify studies that met predetermined inclusion criterion. A random-effects model was used to calculate the pooled risk estimates. Ten prospective cohort studies involving 8973 patients with prostate cancer and 206 096 participants were included in this systematic review. Compared with individuals who seldom or never drink coffee, the pooled relative risk of prostate cancer was 0.88 (95% confidence interval: 0.82-0.95) for regular coffee drinkers. Exclusion of any single study did not materially alter the combined risk estimate. Visual inspection of a funnel plot and Begg's and Egger's tests did not indicate evidence of publication bias. In summary, integrated evidence from prospective cohort studies supports the hypothesis that coffee consumption may decrease the risk of prostate cancer.