Does alcohol consumption modify the risk of endometrial cancer? A dose–response meta-analysis of prospective studies

Background Epidemiological studies have provided controversial evidence of an association between alcohol intake and endometrial cancer (EC) risk. The World Cancer Research Fund/American Institute for Cancer Research classifies alcohol as having a “limited-no conclusion” grade of evidence in the Endometrial Cancer 2013 Report (the latest version). Objective The purpose of this meta-analysis is to systematically analyze the effect of alcohol intake on EC risk. Methods We conducted a dose–response meta-analysis of prospective cohort studies identified from the PubMed, Embase, Cochrane Library and China Biological Medicine databases. Categorical and dose–response meta-analyses were conducted to estimate the effects of alcohol on EC risk. Results A total of 10 studies involving 9766 cases and 1,612,798 participants were included in this meta-analysis. Overall, the relative risk(RR) for alcohol intake on EC was 1.04 (95% CI 0.88–1.22). The RRs for alcohol intake from wine, beer, and liquor were 1.10 (95% CI 0.80–1.51), 0.94 (95% CI 0.72–1.22), and 1.04 (95% CI 0.86–1.27), respectively). When alcohol consumption was stratified by drinking level, the RRs for moderate and heavy alcohol intake were 0.95 (95% CI 0.89–1.01) and 1.00 (95% CI 0.88–1.13), respectively. In the subgroup analyses, this association was not modified by other lifestyle factors or the characteristics of the study design and population. No significant associations were detected in the dose–response meta-analyses. Conclusions Alcohol intake is not associated with EC regardless of the beverage choice and alcohol consumption level. More studies are warranted in other populations, such as Asians and Africans.