Dietary glycemic index, glycemic load, and endometrial cancer risk: The Japan Public Health Center-based Prospective Study.

Evidence supporting the association of glycemic index (GI) and glycemic load (GL) with the risk of endometrial cancer is controversial and reports from Asia were limited. Therefore, we aimed to investigate the association in Japanese women. We evaluated 52 460 women in the Japan Public Health Center-based Prospective Study aged 45-74 years who responded to the 5-year follow-up survey. GI and GL were calculated from a validated food frequency questionnaire, and the participants were divided into three groups by GI and GL. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with the Cox proportional hazard model adjusted for potential confounding factors. As a result, within 15.5 years of follow-up, 166 new cases of endometrial cancer were identified. Compared with the lowest GI and GL tertile groups, the HR of the risk of endometrial cancer in the highest GI tertile group was 0.80 (95% CI, 0.53-1.20; Ptrend  = .33), and that of the highest GL tertile group was 0.79 (95% CI, 0.52-1.19; Ptrend  = .82). The results were unchanged after stratification by body mass index, coffee consumption, and history of diabetes. In conclusion, we did not find any significant association between GI and GL with the risk of endometrial cancer. Further research is required to clarify the association.