Dietary total antioxidant capacity in relation to endometrial cancer risk: a case–control study in Italy

Purpose: To investigate the role of the overall antioxidant activity of diet, we estimated the relation between three dietary indices of total antioxidant capacity (TAC) and endometrial cancer risk Methods: We analyzed data from an Italian case–control study including 454 women with incident, histologically confirmed endometrial cancer, and 908 frequency-matched controls admitted to the same hospitals as cases for acute non-neoplastic conditions. A reproducible and valid food frequency questionnaire was used to assess subjects’ habitual diet. TAC was measured using Italian food composition tables in terms of Ferric-reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC), and total radical-trapping antioxidant parameter (TRAP). We computed odds ratios (OR) and corresponding 95 % confidence intervals (CIs) using conditional multiple logistic regression models, including terms for recognized endometrial cancer risk factors and total energy intake. Results: TAC was inversely related to endometrial cancer risk with ORs for the highest versus the lowest quartile of 0.69 (95 % CI 0.47–1.00) for FRAP, 0.68 (95 % CI 0.46–0.99) for TEAC, and 0.68 (95 % CI 0.47–0.98) for TRAP. The relations appeared consistent in strata of selected risk factors and decreased when considering TAC without the contribution of coffee. Conclusions: Our findings suggest a favorable role of a diet high in TAC on endometrial cancer risk, which can be partially driven by coffee consumption.