%0 Journal Article %J Neurology %D 2014 %T Vitamin D and the risk of dementia and Alzheimer disease. %A Littlejohns, Thomas J %A Henley, William E %A Lang, Iain A %A Annweiler, Cedric %A Beauchet, Olivier %A Chaves, Paulo H M %A Fried, Linda %A Kestenbaum, Bryan R %A Kuller, Lewis H %A Langa, Kenneth M %A Lopez, Oscar L %A Kos, Katarina %A Soni, Maya %A Llewellyn, David J %K Aged %K Alzheimer Disease %K Dementia %K Female %K Follow-Up Studies %K Humans %K Incidence %K Male %K Proportional Hazards Models %K Risk Factors %K United States %K Vitamin D %K Vitamin D Deficiency %X

OBJECTIVE: To determine whether low vitamin D concentrations are associated with an increased risk of incident all-cause dementia and Alzheimer disease.

METHODS: One thousand six hundred fifty-eight elderly ambulatory adults free from dementia, cardiovascular disease, and stroke who participated in the US population-based Cardiovascular Health Study between 1992-1993 and 1999 were included. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were determined by liquid chromatography-tandem mass spectrometry from blood samples collected in 1992-1993. Incident all-cause dementia and Alzheimer disease status were assessed during follow-up using National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association criteria.

RESULTS: During a mean follow-up of 5.6 years, 171 participants developed all-cause dementia, including 102 cases of Alzheimer disease. Using Cox proportional hazards models, the multivariate adjusted hazard ratios (95% confidence interval [CI]) for incident all-cause dementia in participants who were severely 25(OH)D deficient (<25 nmol/L) and deficient (≥25 to <50 nmol/L) were 2.25 (95% CI: 1.23-4.13) and 1.53 (95% CI: 1.06-2.21) compared to participants with sufficient concentrations (≥50 nmol/L). The multivariate adjusted hazard ratios for incident Alzheimer disease in participants who were severely 25(OH)D deficient and deficient compared to participants with sufficient concentrations were 2.22 (95% CI: 1.02-4.83) and 1.69 (95% CI: 1.06-2.69). In multivariate adjusted penalized smoothing spline plots, the risk of all-cause dementia and Alzheimer disease markedly increased below a threshold of 50 nmol/L.

CONCLUSION: Our results confirm that vitamin D deficiency is associated with a substantially increased risk of all-cause dementia and Alzheimer disease. This adds to the ongoing debate about the role of vitamin D in nonskeletal conditions.

%B Neurology %V 83 %P 920-8 %8 2014 Sep 2 %G eng %N 10 %1 http://www.ncbi.nlm.nih.gov/pubmed/25098535?dopt=Abstract %R 10.1212/WNL.0000000000000755