Carbohydrate intake, glycemic index and glycemic load in relation to risk of endometrial cancer: A prospective study of Swedish women

The associations of carbohydrate intake, glycemic index and glycemic load with endometrial cancer risk were examined among 61,226 participants of the Swedish Mammography Cohort who were cancer-free at enrollment between 1987 and 1990 and completed a food frequency questionnaire. During a mean follow-up of 15.6 years, through June 2005, 608 incident cases of endometrial adenocarcinoma were diagnosed. We observed no overall association between carbohydrate intake, glycemic index or glycemic load and incidence of endometrial cancer; the rate ratios (RRs) for the highest versus the lowest quintile were 1.12 (95% CI, 0.85-1.47) for carbohydrate intake, 1.00 (95% CI, 0.77-1.30) for glycemic index and 1.15 (95% CI, 0.88-1.51) for glycemic load. However, among obese women (body mass index, BMI > or =30 kg/m2), endometrial cancer incidence was nonsignificantly elevated in the top versus bottom quintiles of carbohydrate intake (RR, 1.68; 95% CI, 0.86-3.29) and glycemic load (RR, 1.57; 95% CI, 0.82-2.99). In a subanalysis of women who completed a follow-up questionnaire in 1997, which collected information on physical activity, carbohydrate intake and glycemic load were positively related to endometrial cancer risk among overweight women (BMI > or =25 kg/m2) with low physical activity. In this subgroup, the multivariate RRs comparing extreme quartiles were 1.90 (95% CI, 0.84-4.31) for carbohydrate intake and 2.99 (95% CI, 1.17-7.67) for glycemic load. Results from this cohort study suggest that a high carbohydrate intake and a high glycemic load may increase the risk of endometrial cancer among overweight women with low physical activity.