title: Vitamin D and cognitive function.
abstract: The role of vitamin D in skeletal health is well established, but more recent findings have also linked vitamin D deficiency to a range of non-skeletal conditions such as cardiovascular disease, cancer, stroke and metabolic disorders including diabetes. Cognitive impairment and dementia must now be added this list. Vitamin D receptors are widespread in brain tissue, and vitamin D's biologically active form [1,25(OH)(2)D3] has shown neuroprotective effects including the clearance of amyloid plaques, a hallmark of Alzheimer's Disease. Associations have been noted between low 25-hydroxyvitamin D [25(OH)D] and Alzheimer's disease and dementia in both Europe and the US. Similarly, the risk of cognitive impairment was up to four times greater in the severely deficient elders (25(OH)D < 25 nmol/L) in comparison with individuals with adequate levels (≥ 75 nmol/L). Further studies have also shown associations between low 25(OH)D concentrations and cerebrovascular events such as large vessel infarcts, risk of cerebrovascular accident and fatal stroke. Cross-sectional studies cannot establish temporal relationships because cognitive decline and the onset of dementia itself may influence vitamin D concentrations through behavioural and dietary changes. However, two large prospective studies recently indicated that low vitamin D concentrations may increase the risk of cognitive decline. Large, well designed randomized controlled trials are now needed to determine whether vitamin D supplementation is effective at preventing or treating Alzheimer's disease and dementia.
authors.affiliation: Epidemiology and Public Health Group, Institute of Biomedical and Clinical Science, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter, UK.
authors.forename: Maya
authors.initials: M
authors.lastname: Soni
authors.forename: Katarina
authors.initials: K
authors.lastname: Kos
authors.forename: Iain A
authors.initials: IA
authors.lastname: Lang
authors.forename: Kerry
authors.initials: K
authors.lastname: Jones
authors.forename: David
authors.initials: D
authors.lastname: Melzer
authors.forename: David J
authors.initials: DJ
authors.lastname: Llewellyn
mesh_terms: D000375:Aging / Q000502:physiology; D000544:Alzheimer Disease / Q000209:etiology; D000818:Animals; D001921:Brain / Q000502:physiology; D003071:Cognition; D003704:Dementia / Q000209:etiology; D006801:Humans; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood / Q000502:physiology*; D014808:Vitamin D Deficiency / Q000150:complications
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D