Coffee consumption and risk of endometrial cancer: Findings from a large up-to-date meta-analysis

Several epidemiological studies have examined the association between coffee drinking and risk of endometrial cancer. To provide a quantitative assessment of this association, we conducted a meta-analysis of observational studies published up to October 2011 through a search of MEDLINE and EMBASE databases and the reference lists of retrieved article. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using a random-effects model, and generalized least square trend estimation was used to assess doseresponse relationships. A total of 16 studies (10 casecontrol and six cohort studies) on coffee intake with 6,628 endometrial cancer cases were included in the meta-analysis. The pooled RR of endometrial cancer for the highest versus lowest categories of coffee intake was 0.71 (95% CI: 0.620.81; p for heterogeneity = 0.13). By study design, the pooled RRs were 0.69 (95% CI: 0.550.87) for casecontrol studies and 0.70 (95% CI: 0.610.80) for cohort studies. By geographic region, the inverse association was stronger for three Japanese studies (pooled RR = 0.40; 95% CI: 0.250.63) than five studies from USA/Canada (pooled RR = 0.69; 95% CI: 0.600.79) or eight studies from Europe (pooled RR = 0.79; 95% CI: 0.630.99). An increment of one cup per day of coffee intake conferred a pooled RR of 0.92 (95% CI: 0.900.95). In conclusion, our findings suggest that increased coffee intake is associated with a reduced risk of endometrial cancer, consistently observed for cohort and casecontrol studies. More large studies are needed to determine subgroups to obtain more benefits from coffee drinking in relation to endometrial cancer risk.