High-dose antioxidant supplements and cognitive function in community-dwelling elderly women

Background: Experimental data suggest that oxygen free radicals are probably involved in the deterioration of cognitive processes. Objective: Our objective was to investigate the relation of high-dose antioxidant supplements to cognition. Design: Information on the use of specific supplements containing vitamins E and C was collected biennially via mailed questionnaires beginning in 1980 from 14 968 community-dwelling women who participated in the Nurses' Health Study. From 1995 to 2000, telephone tests of cognitive function [Telephone Interview of Cognitive Status (TICS), delayed recall of the TICS 10-word list, immediate and delayed recall of a short paragraph, a test of verbal fluency, and a digit span backwards test] were administered to the women, who were 70-79 y of age at that time. We used linear and logistic regression models to calculate multivariate-adjusted mean differences in test scores and relative risks of a low score for specific supplement users compared with nonusers. Results: Long-term, current users of vitamin E with vitamin C had significantly better mean performance, as judged by a global score that combined individual test scores, than did women who had never used vitamin E or C (P = 0.03); there was a trend for increasingly higher mean scores with increasing durations of use (P = 0.04). These associations were strongest among women with low dietary intakes of alpha-tocopherol. Benefits were less consistent for women taking vitamin E alone, with no evidence of higher scores with longer durations of use. Use of specific vitamin C supplements alone had little relation to performance on our cognitive tests. Conclusion: The use of specific vitamin E supplements, but not specific vitamin C supplements, may be related to modest cognitive benefits in older women.