Association between vitamin D status and the risk of gestational diabetes mellitus: a meta-analysis

Vitamin D is widely used for bone growth and normal insulin secretion; however, the association between vitamin D status and gestational diabetes risk is controversial. This meta-analysis aimed to quantitatively evaluate the association between vitamin status and risk of gestational diabetes. We performed a systematic search on the PubMed, EmBase, and Cochrane Library databases in January 2015 to obtain observational studies studying gestational diabetes risk in relation to vitamin D status. Odds ratios (ORs) with 95 % confidence intervals (CIs) were used to measure the association between vitamin D status and the risk of gestational diabetes. A total of 20 observational studies were included in the final analysis containing 16,515 individuals. Overall, maternal vitamin D insufficiency was found to be associated with a greater risk of gestational diabetes (RR 1.45; 95 % CI 1.15-1.83; P < 0.001). Subgroup analysis indicated that this association might differ based on countries, study design, assessment of vitamin D levels, sample size, age at baseline, adjusted models, and study quality. This meta-analysis revealed that maternal vitamin D insufficiency is associated with increased risk of gestational diabetes.