Vitamin D intake and cognitive decline in Blacks and Whites: The role of diet and supplements.

INTRODUCTION: To determine the role of vitamin D intake on cognitive decline among Blacks and Whites. METHODS: Using data from the population-based Chicago Health and Aging Project, we studied 2061 Blacks and 1329 Whites with dietary vitamin D data and cognitive testing over 12 years of follow-up. Multivariable linear mixed-effects models were used to determine the association of vitamin D intake with cognitive decline. RESULTS: Vitamin D intake, particularly dietary vitamin D, was associated with a slower rate of decline in cognitive function among Blacks. In Blacks, comparing individuals in the lowest tertile of dietary intake, those in the highest tertile had a slower cognitive decline of 0.017 units/year (95% confidence interval 0.006, 0.027), independently of supplementation use. In Whites, vitamin D intake was not associated with cognitive decline. DISCUSSION: Dietary vitamin D may help to slow the decline in cognitive abilities among Blacks as they age.

Vitamin D Intake and Brain Cortical Thickness in Community-Dwelling Overweight Older Adults: A Cross-Sectional Study.

BACKGROUND: Vitamin D is critical to brain health and a promising candidate to prevent cognitive decline and onset of Alzheimer disease (AD), although the underlying brain mechanisms are unclear. OBJECTIVES: This study aimed to determine the association between vitamin D intake and brain cortical thickness in older adults. METHODS: This was a cross-sectional investigation of 263 cognitively unimpaired participants, aged 65 y and older, participating in the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) trial (an ongoing study testing the effects of a 3-y diet intervention on cognitive decline). Vitamin D intake, from diet and supplements, was ascertained from an FFQ. Linear regression analysis, adjusted for age, sex, race, education, income, cognitive and physical activities, and cardiovascular disease risk factors, was used to determine the association between vitamin D intake and cortical thickness of the whole brain, lobes, and AD signature. RESULTS: Total vitamin D intake was associated with cortical thickness of the temporal lobe and AD signature. Compared with individuals in the lowest quartile of total vitamin D intake [median: 140 international units (IU)/d], those in the highest quartile (median: 1439 IU/d) had a 0.038-mm (95% CI: 0.006, 0.069 mm) thicker temporal lobe and 0.041-mm (95% CI: 0.012, 0.070 mm) thicker AD signature. Most vitamin D intake was from supplements, and supplemental intake was also associated with cortical thickness. Compared with those who used no supplement, individuals taking 800-1000 IU/d and >1000 IU/d of supplemental vitamin D had a 0.039-mm (95% CI: 0.013, 0.066 mm) and 0.047-mm (95% CI: 0.013, 0.081 mm) thicker temporal lobe and a 0.037-mm (95% CI: 0.013, 0.061 mm) and 0.046-mm (95% CI: 0.015, 0.077 mm) thicker AD signature, respectively. Dietary vitamin D was not related to brain cortical thickness in our sample. CONCLUSIONS: In cognitively unimpaired older adults, total and supplemental vitamin D intakes were associated with cortical thickness in regions vulnerable to AD.This trial was registered at clinicaltrials.gov as NCT02817074.

Toward a theory-based specification of non-pharmacological treatments in aging and dementia: Focused reviews and methodological recommendations.

INTRODUCTION: Non-pharmacological treatments (NPTs) have the potential to improve meaningful outcomes for older people at risk of, or living with dementia, but research often lacks methodological rigor and continues to produce mixed results. METHODS: In the current position paper, experts in NPT research have specified treatment targets, aims, and ingredients using an umbrella framework, the Rehabilitation Treatment Specification System. RESULTS: Experts provided a snapshot and an authoritative summary of the evidence for different NPTs based on the best synthesis efforts, identified main gaps in knowledge and relevant barriers, and provided directions for future research. Experts in trial methodology provide best practice principles and recommendations for those working in this area, underscoring the importance of prespecified protocols. DISCUSSION: We conclude that the evidence strongly supports various NPTs in relation to their primary targets, and discuss opportunities and challenges associated with a unifying theoretical framework to guide future efforts in this area.