Alcohol and endometrial cancer risk in the NIH-AARP diet and health study

Previous investigations have provided conflicting results regarding whether alcohol consumption affects endometrial cancer risk, although in many of these studies the highest category of alcohol intake examined was limited. Further, most were unable to resolve how alcohol associations are affected by beverage type, the presence of other endometrial cancer risk factors, or tumor characteristics. To address these issues, we prospectively evaluated the association between alcohol intake and incident endometrial cancer (n = 1,491) in a cohort of 114,414 US women enrolled in the NIH-AARP Diet and Health Study. We calculated relative risks (RR) and 95% confidence intervals (CI) using Cox proportional hazards regression. After adjustment for age, body mass index (BMI), smoking and other potential confounders, the multivariable RRs (and 95% CIs) compared with nondrinkers were 0.97 (0.87-1.09) for >0-<12 g of alcohol/day, 1.06 (0.87-1.31) for 12-<24 g/day and 0.93 (0.71-1.20) for ≥ 24 g/day (p trend = 0.90). There was, however, some suggestion of higher risks associated with alcohol consumption among lean women (BMI, <25) and users of menopausal hormone therapy, with significant interactions with both parameters (respective interaction p-values of 0.002 and 0.005). The relationship was also enhanced, albeit nonsignificantly so, for low grade cancers. Our results do not support that alcohol is a strong contributor to endometrial cancer risk, but slight risk increases may prevail among some users or for selected tumor characteristics.