Vitamin D Intake and Risk of Type 1 Diabetes: A Meta-Analysis of Observational Studies

Nutrients. 2013 Sep 12;5(9):3551-62. doi: 10.3390/nu5093551.

Abstract

Vitamin D is suggested to have protective effects against type 1 diabetes. However, the results from observational studies have been inconsistent. We aimed to examine their association by conducting a meta-analysis of observational studies. Multiple databases were searched in June 2013 to identify relevant studies including both case-control and cohort studies. Either a fixed- or random-effects model was used to calculate the pooled risk estimate. We identified eight studies (two cohort studies and six case-control studies) on vitamin D intake during early life and three studies (two cohort studies and one case-control study) on maternal vitamin D intake during pregnancy. The pooled odds ratio for type 1 diabetes comparing vitamin D supplementation with non-supplementation during early life was 0.71 (95% confidence interval [CI], 0.51-0.98). Similar results were observed in the case-control subgroup analysis but not in the cohort subgroup analysis. The pooled odds ratio with maternal intake of vitamin D during pregnancy was 0.95 (95% CI, 0.66-1.36). In conclusion, vitamin D intake during early life may be associated with a reduced risk of type 1 diabetes. However, there was not enough evidence for an association between maternal intake of vitamin D and risk of type 1 diabetes in the offspring.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Databases, Factual
  • Diabetes Mellitus, Type 1 / prevention & control*
  • Dietary Supplements*
  • Humans
  • Observational Studies as Topic
  • Odds Ratio
  • Risk Factors
  • Vitamin D / administration & dosage*
  • Vitamin D / blood
  • Vitamins / administration & dosage*
  • Vitamins / blood

Substances

  • Vitamins
  • Vitamin D