Objective: Vitamin D may have protective effects against type 1 diabetes (T1D). However, the results of current cross-sectional studies have been inconsistent. We aimed to examine the association of serum vitamin D and T1D by conducting a meta-analysis.
Methods: Multiple databases were searched until April 2014 to identify relevant studies. The search term was "serum vitamin D" and "type 1 diabetes". Random effects model was used to calculate the pooled risk estimate. The data were accessed by software Review manager 5.2.
Results: We included a total of 23 studies (11 studies with 1900 participants of children or adolescents and 13 studies with 3494 participants of adults) in our meta-analysis. In children or adolescents, serum 25(OH) D in T1D was 5.69 ng/ml [95% confidence interval (CI) (2.82-8.55, P<0.0001) lower than in healthy controls. In adults, serum 25(OH) D in T1D was 2.61 ng/ml [95% confidence interval (CI) (1.13-4.09, P=0.0005) lower than in healthy controls. We did not find evidence of publication bias.
Conclusion: Serum 25OHD is significantly lower in patients with T1D than in healthy controls.
Keywords: Meta-analysis; Serum vitamin D; Type 1 diabetes.
Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.