Coffee drinking and endometrial cancer risk: a metaanalysis of observational studies.

We conducted a metaanalysis of published studies on the relation between coffee drinking and endometrial cancer risk, which included 2 cohort (201 cases) and 7 case-control studies (2409 cases). The summary relative risk (RR) for coffee drinkers vs nondrinkers was 0.80 (95% confidence interval [CI], 0.68-0.94), with significant heterogeneity between studies. Compared with nondrinkers, the summary RR was 0.87 (95% CI, 0.78-0.97) for low-to-moderate coffee drinkers and 0.64 (95% CI, 0.48-0.86) for heavy coffee drinkers. The summary RR for an increase of 1 cup/d was 0.93 (95% CI, 0.89-0.97), which suggests an inverse relation between coffee and endometrial cancer. However, the causality must be confirmed.