Alzheimer's disease 30 percent more likely in the 30 years after a low vitamin D test – July 2013

Reduced 25-hydroxyvitamin D and risk of Alzheimer's disease and vascular dementia.

Alzheimers Dement. 2013 Jul 18. pii: S1552-5260(13)02425-4. doi: 10.1016/j.jalz.2013.05.1765.
Afzal S, Bojesen SE, Nordestgaard BG.
The Department of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital, Herlev, Denmark.

BACKGROUND: Vitamin D deficiency has been implicated as a risk factor for dementia in several cross-sectional studies.
We tested the hypothesis that reduced plasma 25-hydroxyvitamin D (25[OH]D) is associated with increased risk of Alzheimer's disease (AD) and vascular dementia in the general population.

METHODS: We measured baseline plasma 25(OH)D in 10,186 white individuals from the Danish general population.

RESULTS: During 30 years of follow-up, 418 participants developed AD and 92 developed vascular dementia.
Multivariable adjusted hazard ratios for AD were 1.25 (95% confidence interval [CI], 0.95-1.64) for 25(OH)D less than 25 nmol/L vs. greater than or equal to 50 nmol/L, and 1.29 (95% CI, 1.01-1.66) for less than the 25th seasonally adjusted 25(OH)D percentile vs. more than the 50th seasonally adjusted 25(OH)D percentile.

Multivariable adjusted hazard ratios for vascular dementia were 1.22 (95% CI, 0.77-1.91) for 25(OH)D less than 50 nmol/L vs. greater than or equal to 50 nmol/L, and 1.22 (95% CI, 0.79-1.87) for less than or equal to the 50th vs. more than the 50th seasonally adjusted 25(OH)D percentile. Last, multivariable adjusted hazard ratios for the combined end point were 1.28 (95% CI, 1.00-1.64) for 25(OH)D less than 25 nmol/L vs. greater than or equal to 50 nmol/L, and 1.27 (95% CI, 1.01-1.60) for less than the 25th vs. more than the 50th seasonally adjusted 25(OH)D.

CONCLUSIONS: We observed an association of reduced plasma 25(OH)D with increased risk of the combined end point of AD and vascular dementia in this prospective cohort study of the general population.

Copyright © 2013 The Alzheimer's Association. Published by Elsevier Inc. All rights reserved.

PMID: 23871764

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This study ignores the many things which can happen in 30 years, and yet still finds an association

• Get a disease, take a medicine, or change behaviour (such as taking up smoking) which decreases vitamin D levels
• Start taking vitamin D supplements
• Spend more/less time out in the sun
• Spend more/less time on suncations (vacations in sunny climates)

See also VitaminDWiki

• Overview Alzheimer's-Cognition and Vitamin D
• All items in category Cognition and vitamin D 391 items
• Brain (Alzheimer’s) worked better with Vitamin D intervention – meta-analysis July 2013
• Cognitive decline associated with low vitamin D in 72 percent of studies – meta-analysis June 2013
• Alzheimer's disease most likely will need more than monotherapy such as vitamin D – May 2013
• Overview Deficiency of vitamin D which has the following chart