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Dementia risk factor is increased by 1.5 if low vitamin D – meta-analysis Jan 2017

Vitamin D deficiency as a risk factor for dementia: a systematic review and meta-analysis.

BMC Geriatr. 2017 Jan 13;17(1):16. doi: 10.1186/s12877-016-0405-0.

VitaminDWiki Summary

This is a meta-analysis of observational studies
Test vitamin D then wait 5-30 years and see who gets dementia
They did not look at vitamin D levels at time of dementia
   Vitamin D levels will drop over the decades due to Diabetes, Multiple Sclerosis, Stroke, etc
Dementia risk factor 1.54 times higher if < 10 ng vs > 20 ng
Important confounders ignored included genes (Alzheimer’s, VDR, etc.), obesity, skin color, etc
See also VitaminDWiki

Items in categories Cognition and Meta-analysis

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Sommer I1, Griebler U2,3, Kien C2,3, Auer S4,5, Klerings I2,3, Hammer R6, Holzer P6, Gartlehner G2,3,7.
1Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria. isolde.sommer at donau-uni.ac.at.
2Department for Evidence-based Medicine and Clinical Epidemiology, Danube University Krems, Dr.-Karl-Dorrek-Straße 30, 3500, Krems, Austria.
3Cochrane Austria, Danube University Krems, Krems, Austria.
4Department for Clinical Neurosciences and Preventive Medicine, Danube University, Krems, Austria.
5MAS Alzheimerhilfe, Bad Ischl, Austria.
6Institute of Building Research & Innovation ZT-GmbH, Vienna, Austria.
7RTI-UNC Evidence-based Practice Center, Research Triangle Institute International, North Carolina, USA.

Sunlight exposure and high vitamin D status have been hypothesised to reduce the risk of developing dementia. The objective of our research was to determine whether lack of sunlight and hypovitaminosis D over time are associated with dementia.

We systematically searched MEDLINE (via PubMed), Cochrane Library, EMBASE, SCOPUS, Web of Science, ICONDA, and reference lists of pertinent review articles from 1990 to October 2015. We conducted random effects meta-analyses of published and unpublished data to evaluate the influence of sunlight exposure or vitamin D as a surrogate marker on dementia risk.

We could not identify a single study investigating the association between sunlight exposure and dementia risk. Six cohort studies provided data on the effect of serum vitamin D concentration on dementia risk. A meta-analysis of five studies showed a higher risk for persons with serious vitamin D deficiency (<25 nmol/L or 7-28 nmol/L) compared to persons with sufficient vitamin D supply (=50 nmol/L or 54-159 nmol/L) (point estimate 1.54; 95% CI 1.19-1.99, I2 = 20%). The strength of evidence that serious vitamin D deficiency increases the risk of developing dementia, however, is very low due to the observational nature of included studies and their lack of adjustment for residual or important confounders (e.g. ApoE e4 genotype), as well as the indirect relationship between Vitamin D concentrations as a surrogate for sunlight exposure and dementia risk.

The results of this systematic review show that low vitamin D levels might contribute to the development of dementia. Further research examining the direct and indirect relationship between sunlight exposure and dementia risk is needed. Such research should involve large-scale cohort studies with homogeneous and repeated assessment of vitamin D concentrations or sunlight exposure and dementia outcomes.

PMID: 28086755 DOI: 10.1186/s12877-016-0405-0

Attached files

ID Name Comment Uploaded Size Downloads
7666 Dementia.jpg admin 15 Jan, 2017 31.26 Kb 719
7665 risk factor for dementia.pdf admin 15 Jan, 2017 526.15 Kb 694