Low Serum Vitamin D Concentrations in Alzheimer's Disease: A Systematic Review and Meta-Analysis.

J Alzheimers Dis. 2012 Oct 5.
Annweiler C ceannweiler at chu-angers.fr., Llewellyn DJ, Beauchet O.
Department of Neuroscience, Division of Geriatric Medicine and Memory Clinic, Angers University Hospital, UPRES EA 2646, University of Angers, UNAM, Angers, France Department of Medicine, Division of Geriatric Medicine, Parkwood Hospital, St. Joseph's Health Care London, Lawson Health Research Institute, Western University, London, ON, Canada.

Vitamin D has been investigated in association with cognitive function in older adults. It is unclear whether hypovitaminosis D could be associated with Alzheimer's disease (AD). Our objective was to systematically review and quantitatively synthesize the association of low serum 25-hydroxyvitamin D (25OHD) concentrations with AD in adults.

A Medline and PsycINFO® search was conducted on May 2012, with no limit of date, using the MeSH terms "Vitamin D" OR "Hydroxycholecalciferols" combined with the MeSH terms "Alzheimer disease" OR "Dementia" OR "Cognition" OR "Cognition disorders" OR "Memory" OR "Memory Disorders" OR "Executive Function" OR "Attention" OR "Neuropsychological Tests".

Of the 284 selected studies, 10 observational studies (including 9 case-controls and 1 cohort study) met the selection criteria. All were of good quality. The number of AD cases ranged from 20 to 211 (40%-100% female). Finally, 7 case-control studies were eligible for fixed and random-effects meta-analyses of bias-corrected effect size of the difference in serum 25OHD concentrations between AD cases and controls using an inverse-variance method.

The pooled effect size in random-effects meta-analysis was 1.40 (95% CI: 0.26;2.54), a 'large' effect size that indicates that serum 25OHD concentrations were 1.4 standard deviation units lower in AD cases compared to cognitively healthy controls (p = 0.016).

In conclusion, AD cases had lower serum vitamin D concentrations than matched controls. This reinforces the conceptualization of vitamin D as a 'neurosteroid hormone' and as a potential biomarker of AD.

PMID: 23042216
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See also VitaminDWiki

• Dementia 19X more likely if low vitamin D – Jan 2012 also by Annweiler
• Alzheimer’s 4X less likely with high level of vitamin D – 2 studies April 2012 one article co-authored by Annweiler
• Overview Cognition and vitamin D
• Dementia 19X more likely if < 10 ng of vitamin D – Jan 2012
• 'Senior moment" 25X more likely with low vitamin D – Feb 2012
• Alzheimer's patients are genetically 70 percent more likely to be vitamin D in-efficient – Feb 2012
• Brain lesions might be associated with vitamin D deficiency – March 2012 co-authored Annweiler
• Alzheimer disease associated with 2.5 ng less vitamin D – meta-analysis Sept 2012
• All items in category Cognition and Vitamin D 391 items
• Dementia risk increases 60 percent if have low vitamin D – Nov 2012
• Vitamin D reduces Alzheimer’s disease in at least 11 ways – Jan 2013