The association of tea consumption and the risk and progression of prostate cancer: a meta-analysis.

Many studies have focused on the association of tea consumption and the risk and progression of prostate cancer (PCa). However, the evidence is inadequate to draw robust conclusions. To shed light on these inconclusive findings, we conducted a meta-analysis. We searched the database of PubMed and Web of Science for eligible articles. The relevant data were abstracted by two independent reviewers and performed with Stata 11.0. 21 studies were included. The pooled outcomes showed that there was a significant association between tea consumption and PCa risk (OR=0.84, 95% CI (0.71-0.98)); tea consumption could reduce PCa risk in China and India (OR=0.40 and 0.48, 95% CI (0.25-0.66) and (0.24-0.97), respectively); both green and black tea consumption showed no significant effect on PCa risk (OR=0.73 and 0.95, 95% CI (0.52-1.02) and (0.82-1.11), respectively); the highest level tea consumption showed significant protective effect on the low-grade PCa (OR=0.66, 95% CI (0.46-0.93)); no significant effect was found in both localized and advanced PCa in stage subgroup analyses (OR=1.12 and 0.85, 95% CI (0.82-1.54) and (0.62-1.16), respectively). The results show that regardless of tea type, tea consumption might be a potential protective factor for the PCa, especially in China and India. Tea consumption might be the protective factor for low-grade PCa. However, more relevant studies are needed to further explore this association.