Kumar, AbhaiChaurasia, Rameshwar NathSingh, SmitaSingh, Anup2025-01-302025-01-302021978-042931931-0; 978-036733322-5https://dl.bhu.ac.in/ir/handle/123456789/25521The incidence of vitamin D deficiency is more than 40% in American and European elderly population. This chapter summarizes the neurological role of vitamin D and its implication in neuroprotection during age-associated progressive neurodegeneration resulting in cognitive impairment among the elderly. The US endocrine society has reported that the prevalence of vitamin D deficiency is almost one-third of the US population. Vitamin D induces amyloid clearance through phagocytosis, thereby leading to neuroprotection. Annweiler et al. analyzed the data based on a regression model and reported that in older adults vitamin D deficiency was associated with dementia and that vitamin D supplementation has a protective effect. A meta-analysis involving cross-sectional studies could not explain whether vitamin D deficiency leads to cognitive decline, or whether people with cognition disorder have lower exposure to sunlight or lower vitamin D intake; moreover, the seasonal fluctuation of vitamin D status was clear. � 2021 Taylor & Francis Group, LLC. All rights reserved.Book chapter