@article {7017, title = {Vitamin D and the risk of dementia and Alzheimer disease.}, journal = {Neurology}, volume = {83}, year = {2014}, month = {2014 Sep 2}, pages = {920-8}, abstract = {

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{\textquoteright}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.

}, keywords = {Aged, Alzheimer Disease, Dementia, Female, Follow-Up Studies, Humans, Incidence, Male, Proportional Hazards Models, Risk Factors, United States, Vitamin D, Vitamin D Deficiency}, issn = {1526-632X}, doi = {10.1212/WNL.0000000000000755}, author = {Littlejohns, Thomas J and Henley, William E and Lang, Iain A and Annweiler, Cedric and Beauchet, Olivier and Chaves, Paulo H M and Fried, Linda and Kestenbaum, Bryan R and Kuller, Lewis H and Langa, Kenneth M and Lopez, Oscar L and Kos, Katarina and Soni, Maya and Llewellyn, David J} } @article {7126, title = {Vitamin D and Risk of Neuroimaging Abnormalities.}, journal = {PLoS One}, volume = {11}, year = {2016}, month = {2016}, pages = {e0154896}, abstract = {

Vitamin D deficiency has been linked with an increased risk of incident all-cause dementia and Alzheimer{\textquoteright}s disease. The aim of the current study was to explore the potential mechanisms underlying these associations by determining whether low vitamin D concentrations are associated with the development of incident cerebrovascular and neurodegenerative neuroimaging abnormalities. The population consisted of 1,658 participants aged >=65 years from the US-based Cardiovascular Health Study who were free from prevalent cardiovascular disease, stroke and dementia at baseline in 1992-93. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were determined by liquid chromatography-tandem mass spectrometry from blood samples collected at baseline. The first MRI scan was conducted between 1991-1994 and the second MRI scan was conducted between 1997-1999. Change in white matter grade, ventricular grade and presence of infarcts between MRI scan one and two were used to define neuroimaging abnormalities. During a mean follow-up of 5.0 years, serum 25(OH)D status was not significantly associated with the development of any neuroimaging abnormalities. Using logistic regression models, the multivariate adjusted odds ratios (95\% confidence interval) for worsening white matter grade in participants who were severely 25(OH)D deficient (<25 nmol/L) and deficient (>=25-50 nmol/L) were 0.76 (0.35-1.66) and 1.09 (0.76-1.55) compared to participants with sufficient concentrations (>=50 nmol/L). The multivariate adjusted odds ratios for ventricular grade in participants who were severely 25(OH)D deficient and deficient were 0.49 (0.20-1.19) and 1.12 (0.79-1.59) compared to those sufficient. The multivariate adjusted odds ratios for incident infarcts in participants who were severely 25(OH)D deficient and deficient were 1.95 (0.84-4.54) and 0.73 (0.47-1.95) compared to those sufficient. Overall, serum vitamin D concentrations could not be shown to be associated with the development of cerebrovascular or neurodegenerative neuroimaging abnormalities in Cardiovascular Health Study participants.

}, issn = {1932-6203}, doi = {10.1371/journal.pone.0154896}, author = {Littlejohns, Thomas J and Kos, Katarina and Henley, William E and Lang, Iain A and Annweiler, Cedric and Beauchet, Olivier and Chaves, Paulo H M and Kestenbaum, Bryan R and Kuller, Lewis H and Langa, Kenneth M and Lopez, Oscar L and Llewellyn, David J} }