Vitamin D Status and Intakes and Their Association With Cognitive Trajectory in a Longitudinal Study of Urban Adults

Context: Serum 25-hydroxyvitamin D [25(OH)D], and dietary and supplemental vitamin D may influence cognitive outcomes. Objectives: Sex-, age-, and race-specific associations of vitamin D status and intake with longitudinal change in various cognitive domains were examined in a large sample of ethnically and socioeconomically diverse US urban adults. Design: Two prospective waves of data from the Healthy Aging in Neighborhoods of Diversity across the Life Span study were used. Participants: Adults in Baltimore, Maryland, aged 30 to 64 years at baseline (n = 1231 to 1803), were followed for a mean (+/- standard deviation) of 4.64 +/- 0.93 years. Visit 1 occurred between 2004 and 2009; visit 2, between 2009 and 2013; there were 1.5 to 2.0 visits per participant. Main outcome and exposure measures: Cognitive performance was assessed using 11 test scores covering domains of global cognition, attention, learning/memory, executive function, visuospatial/visuoconstruction ability, psychomotor speed, and language/verbal. Serum 25(OH)D, vitamin D intake, and use of supplements containing vitamin D were the key exposures. Results: A consistent relationship was found between vitamin D status (overall) and supplemental intake (older women and black adults), with a slower rate of decline in the domain of verbal fluency. Higher dietary intake of vitamin D was linked to slower rate of decline in verbal memory among younger women, and a slower rate of decline in visual memory/visuoconstructive abilities among white adults. All other associations were inconsistent. Conclusions: Vitamin D status and intakes were inversely related to domain-specific cognitive decline in US urban adults.