Tea and coffee and risk of endometrial cancer: cohort study and meta-analysis

Background: Previous reports, mostly from retrospective studies, suggested possible protective effects of both tea and coffee against endometrial cancer, but recent reports from prospective studies generally showed weaker or null associations. Objectives: We investigated endometrial cancer risk in relation to tea and coffee consumption in a large prospective study and did a meta-analysis of published results. Design: Daily consumption of tea and coffee was recorded in 560,356 participants (without a hysterectomy) in the UK Million Women Study of whom 4067 women developed endometrial cancer during 5.2 million person-years of follow up (average: 9.3 y per woman). Results: With the use of Cox proportional hazards regression, we showed no significant association between endometrial cancer risk and consumption of either tea (multivariate adjusted RR per cup daily: 1.00; 95% CI: 0.98, 1.02) or coffee (RR per cup daily: 0.98; 95% CI: 0.96, 1.01). Our meta-analyses showed no significant association between endometrial cancer risk and tea consumption and a weak association for coffee consumption in prospective studies, but there may have been selective publication of only part of the evidence. Conclusions: There is little or no association between tea consumption and endometrial cancer risk. If there is any association with coffee consumption, it appears to be weak.