Total Antioxidant Capacity of the Diet and Risk of Age-Related Cataract

IMPORTANCE: To our knowledge, no previous epidemiologic study has investigated the association between all antioxidants in the diet and age-related cataract. The total antioxidant capacity (TAC) concept aims to measure the capacity from all antioxidants in the diet by also taking synergistic effects into account. OBJECTIVE: To investigate the association between the TAC of the diet and the incidence of age-related cataract in a population-based prospective cohort of middle-aged and elderly women. DESIGN, SETTING, AND PARTICIPANTS: Questionnaire-based nutrition survey within the prospective Swedish Mammography Cohort study, which included 30,607 women (aged 49-83 years) who were observed for age-related cataract incidence for a mean of 7.7 years. EXPOSURE: The TAC of the diet was estimated using a database of foods analyzed with the oxygen radical absorbance capacity assay. MAIN OUTCOMES AND MEASURES: Information on incident age-related cataract diagnosis and extraction was collected through linkage to registers in the study area. RESULTS: There were 4309 incident cases of age-related cataracts during the mean 7.7 years of follow-up (234,371 person-years). The multivariable rate ratio in the highest quintile of the TAC of the diet compared with the lowest was 0.87 (95% CI, 0.79-0.96; P for trend = .03). The main contributors to dietary TAC in the study population were fruit and vegetables (44.3%), whole grains (17.0%), and coffee (15.1%). CONCLUSIONS AND RELEVANCE: Dietary TAC was inversely associated with the risk of age-related cataract. Future studies examining all antioxidants in the diet in relation to age-related cataract are needed to confirm or refute our findings.