Vitamin D intake and cognitive decline in African Americans and European Americans: The role of diet and supplements

Abstract

AbstractBackgroundVitamin D intake and supplementation has received considerable interest in dementia research because the prevalence of vitamin D deficiency is higher among older adults, particularly among older African Americans and cognitively impaired individuals. We prospectively examined the role of vitamin D intake, from both diet and supplements, in association with cognitive decline in African Americans and European Americans.MethodUtilizing data from the population‐based Chicago Health and Aging Project, we studied 2,061 African Americans and 1,329 European Americans with dietary vitamin D data and cognitive testing over 18 years of follow‐up. Multivariable linear mixed‐effects models adjusted for age, sex, education, APOE e4, body mass index, late‐life cognitive activities, physical activity, comorbidities, total energy intake, and their respective interactions with follow‐up time were used to determine the association of vitamin D intake with cognitive decline.ResultOn average, the vitamin D intake was lower in African Americans than European Americans (210.2 IU/d vs. 348.7 IU/d). In African Americans, participants in the highest tertile had a slower cognitive decline of 0.019 units/year (95%CI 0.009, 0.030) compared to those in the lowest tertile of dietary intake. The use of vitamin D supplementation was not associated with cognitive decline in African Americans (β 0.004, 95%CI ‐0.006, 0.013). In European Americans, vitamin D intake was not associated with cognitive decline.ConclusionDietary vitamin D may help slow the rate of cognitive decline in African Americans as they age.