Serum α-tocopherol, concurrent and past vitamin E intake, and mild cognitive impairment

Abstract

Associations of past dietary vitamin E intake, past and current vitamin E supplement use, and current serum alpha-tocopherol levels, with memory (amnestic) and mixed-domain cognitive impairment in older women, ascertained from an in-depth neuropsychological assessment, were explored. This analysis used baseline data from 526 participants in a single-site ancillary study to the Women's Health Initiative, the Cognitive Change in Women study. In bivariate analyses, neither past dietary vitamin E intake (<8 mg/day vs more) nor current vitamin E supplement use was associated with impairment. Women who did not use vitamin E supplements at Women's Health Initiative baseline had an increased risk of mixed-domain impairment (odds ratio [OR] 1.88; 95% CI 1.09 to 3.23). This association lost significance when adjusting for age, education, American National Adult Reading Test (ANART) score, and time between measurement of past vitamin E use and cognitive testing. Concurrent serum alpha-tocopherol had significant cross-sectional associations with both memory and mixed impairments, with women in the lowest quartile of serum alpha-tocopherol nearly twice as likely to show signs of memory (1.92; 1.24 to 2.97) and mixed-domain (2.01; 1.13 to 3.57) impairments. In multivariable models adjusting for age, education, and ANART score, the lowest quartile of serum alpha-tocopherol was associated with increased odds of memory impairment (OR 2.02; 1.27 to 3.20) and mixed impairments (OR 2.00; 1.04 to 3.85). Additional adjustment for APOE e4 did not affect these results. There was weak or no evidence of a protective effect of previous vitamin E intake on cognitive function. However, the association of low concurrent serum alpha-tocopherol with memory and mixed impairment merits further exploration.