Vitamin E, Vitamin C, Beta Carotene, and Cognitive Function Among Women With or at Risk of Cardiovascular Disease

Abstract

Background— Cardiovascular factors are associated with cognitive decline. Antioxidants may be beneficial. Methods and Results— The Women’s Antioxidant Cardiovascular Study was a trial of vitamin E (402 mg every other day), beta carotene (50 mg every other day), and vitamin C (500 mg daily) for the secondary prevention of cardiovascular disease. From 1995 to 1996, women ≥40 years of age with cardiovascular disease or ≥3 coronary risk factors were randomized. From 1998 to 1999, a cognitive function substudy was initiated among 2824 participants ≥65 years of age. With 5 cognitive tests, cognition was assessed by telephone 4 times over 5.4 years. The primary outcome was a global composite score averaging all scores; repeated-measures analyses were used to examine cognitive change over time. Vitamin E supplementation and beta carotene supplementation were not associated with slower rates of cognitive change (mean difference in change for vitamin E versus placebo, −0.01; 95% confidence interval, −0.05 to 0.04; P =0.78; for beta carotene, 0.03; 95% confidence interval, −0.02 to 0.07; P =0.28). Although vitamin C supplementation was associated with better performance at the last assessment (mean difference, 0.13; 95% confidence interval, 0.06 to 0.20; P =0.0005), it was not associated with cognitive change over time (mean difference in change, 0.02; 95% confidence interval, −0.03 to 0.07; P =0.39). Vitamin C was more protective against cognitive change among those with new cardiovascular events during the trial ( P for interaction=0.009). Conclusions— Antioxidant supplementation did not slow cognitive change among women with preexisting cardiovascular disease or cardiovascular disease risk factors. A possible late effect of vitamin C or beta carotene among those with low dietary intake on cognition warrants further study.