title: Vitamin D deficiency and depression in adults: systematic review and meta-analysis.
abstract: BACKGROUND
  There is conflicting evidence about the relationship between vitamin D deficiency and depression, and a systematic assessment of the literature has not been available.
  
  
  OBJECTIVE
  To determine the relationship, if any, between vitamin D deficiency and depression.
  
  
  METHODS
  A systematic review and meta-analysis of observational studies and randomised controlled trials was conducted.
  
  
  RESULTS
  One case-control study, ten cross-sectional studies and three cohort studies with a total of 31 424 participants were analysed. Lower vitamin D levels were found in people with depression compared with controls (SMD = 0.60, 95% CI 0.23-0.97) and there was an increased odds ratio of depression for the lowest v. highest vitamin D categories in the cross-sectional studies (OR = 1.31, 95% CI 1.0-1.71). The cohort studies showed a significantly increased hazard ratio of depression for the lowest v. highest vitamin D categories (HR = 2.21, 95% CI 1.40-3.49).
  
  
  CONCLUSIONS
  Our analyses are consistent with the hypothesis that low vitamin D concentration is associated with depression, and highlight the need for randomised controlled trials of vitamin D for the prevention and treatment of depression to determine whether this association is causal.
authors: Department of Psychiatry and Behavioural Neurosciences, St Joseph's Hospital, 50 Charlton Avenue E, Hamilton, Ontario, Canada. anglinr@mcmaster.ca
authors: Rebecca E S
authors: RE
authors: Anglin
authors: Zainab
authors: Z
authors: Samaan
authors: Stephen D
authors: SD
authors: Walter
authors: Sarah D
authors: SD
authors: McDonald
mesh_terms: D000328:Adult; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D003866:Depressive Disorder / Q000150:complications / Q000453:epidemiology*; D016021:Epidemiologic Studies; D006801:Humans; D016017:Odds Ratio; D014808:Vitamin D Deficiency / Q000150:complications / Q000453:epidemiology*