Vitamin D supplementation in early childhood and risk of type 1 diabetes: a systematic review and meta-analysis

Arch Dis Child. 2008 Jun;93(6):512-7. doi: 10.1136/adc.2007.128579. Epub 2008 Mar 13.

Abstract

Objectives: To assess whether vitamin D supplementation in infancy reduces the risk of type 1 diabetes in later life.

Methods: This was a systematic review and meta-analysis using Medline, Embase, Cinahl, Cochrane Central Register of Controlled Trials and reference lists of retrieved articles. The main outcome measure was development of type 1 diabetes. Controlled trials and observational studies that had assessed the effect of vitamin D supplementation on risk of developing type 1 diabetes were included in the analysis.

Results: Five observational studies (four case-control studies and one cohort study) met the inclusion criteria; no randomised controlled trials were found. Meta-analysis of data from the case-control studies showed that the risk of type 1 diabetes was significantly reduced in infants who were supplemented with vitamin D compared to those who were not supplemented (pooled odds ratio 0.71, 95% CI 0.60 to 0.84). The result of the cohort study was in agreement with that of the meta-analysis. There was also some evidence of a dose-response effect, with those using higher amounts of vitamin D being at lower risk of developing type 1 diabetes. Finally, there was a suggestion that the timing of supplementation might also be important for the subsequent development of type 1 diabetes.

Conclusion: Vitamin D supplementation in early childhood may offer protection against the development of type 1 diabetes. The evidence for this is based on observational studies. Adequately powered, randomised controlled trials with long periods of follow-up are needed to establish causality and the best formulation, dose, duration and period of supplementation.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Adolescent
  • Age Factors
  • Case-Control Studies
  • Child
  • Child, Preschool
  • Diabetes Mellitus, Type 1 / diet therapy
  • Diabetes Mellitus, Type 1 / prevention & control*
  • Dose-Response Relationship, Drug
  • Humans
  • Infant
  • Vitamin D / administration & dosage*
  • Vitamin D Deficiency / diet therapy
  • Vitamin D Deficiency / immunology*
  • Vitamins / administration & dosage*

Substances

  • Vitamins
  • Vitamin D