Vitamin D deficiency, cognitive impairment and dementia: a systematic review and meta-analysis

Dement Geriatr Cogn Disord. 2012;33(5):297-305. doi: 10.1159/000339702. Epub 2012 Jul 2.


Background: Recent preventive strategies for patients with cognitive impairment include the identification of modifiable somatic risk factors like vitamin D deficiency.

Methods: A systematic literature research and meta-analysis were conducted to assess the association of cognitive impairment and vitamin D deficiency.

Results: Data from cross-sectional and longitudinal studies suggest an association between cognitive impairment and vitamin D deficiency. Meta-analysis of 5 cross-sectional and 2 longitudinal studies comprising 7,688 participants showed an increased risk of cognitive impairment in those with low vitamin D compared with normal vitamin D (OR 2.39, 95% CI 1.91-3.00; p < 0.0001).

Conclusions: Methodological limitations of these studies comprise heterogeneity of study populations, different forms of cognitive assessment, the problem of reverse causality, different definitions of vitamin D deficiency and inconsistent control for confounders. As the value of vitamin D substitution in cognitive impairment remains doubtful, a long-time major placebo-controlled randomized trial of vitamin D supplementation in participants with mild cognitive impairment (MCI) should be started.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Cognitive Dysfunction / etiology
  • Cognitive Dysfunction / physiopathology*
  • Dementia / etiology
  • Dementia / prevention & control*
  • Humans
  • Risk Factors
  • Vitamin D / metabolism*
  • Vitamin D / therapeutic use
  • Vitamin D Deficiency / physiopathology*


  • Vitamin D