Vitamin D Research Today is a free monthly online journal that collates and summarizes the latest research about Vitamin D, including details on sources, melanin, benefits, deficiency, supplements, calcium absorption.

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

Zipitis CS, Akobeng AK

Department of Paediatrics, Stockport NHS Foundation Trust, Poplar Grove, Stockport SK2 7JE, UK. czipitis@hotmail.com

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.

Published 22 May 2008 in Arch Dis Child, 93(6): 512-7.
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