Tea Consumption and Endometrial Cancer Risk: Meta-Analysis of Prospective Cohort Studies

Several lines of evidence suggest that tea consumption may reduce the risk of endometrial cancer due to antioxidant properties of tea, but the results of prospective data to date are inconsistent. We thus conducted a meta-analysis of prospective cohort studies to examine the relationship between tea consumption and endometrial cancer risk, using a random-effects model. We identified 5 eligible cohort studies, which included 231,870 female participants and 1831 cases for endometrial cancer. The pooled relative risk (RR) for the highest (median 2 cups/day) vs. no/lowest category of tea consumption on endometrial cancer risk was 0.95 [95% confidence interval (CI): 0.80-1.12] with no significant heterogeneity (P for heterogeneity = 0.68, I(2) = 0.0%). By country of origin, the pooled RR of 3 studies conducted in the United States was 1.00 (95% CI: 0.83-1.21), in which black tea was consumed by most people. Because of limited data on Asian population, the association of green tea on endometrial cancer was not calculated separately. There was no indication of publication bias (Begg's P = 0.46; Egger's P = 0.43). Our findings from prospective data do not support a role of tea consumption in endometrial carcinogenesis. More prospective cohort studies with green tea consumption should be conducted.