The relationship between vitamin D and gestational diabetes

Background: Gestational diabetes is one of the common causes of maternal and fetal complications. Due to fetal and maternal complications of diabetes, it is very important to reduce the prevalence of diabetes and its consequences. The relationship between vitamin D deficiency and type 2 diabetes has been reported. There is little information about the relationship between serum vitamin D levels and the risk of gestational diabetes mellitus (GDM). The aim of this study was to determine the relationship between the levels of vitamin D and gestational diabetes. Methods: This case-control study was conducted in health centers of Urmia University of Medical Sciences in May 2015 until March 2016. A total of 100 pregnant women with gestational diabetes and 100 healthy pregnant women were entered into the study by nonrandom and available sampling. The level of vitamin D was measured and levels were divided into three levels. Vitamin D levels were considered less than 20 ng/ml, 20-30 ng/ml and more than 30 ng/ml as deficiency, insufficiency and sufficient, respectively. Exclusion criteria include pre-pregnancy glucose tolerance, history of medical disease, and supplementation with vitamin D. Results: The mean age of women in the study group was 30.31±5 years and in the control group was 28.83±4.95 years (P=0.06). The vitamin D levels in GDM and control groups were 7.25±4.76 ng/ml and 11.93±16.12 ng/ml, which is lower in the gestational diabetes than the control group (P=0.01). The severe deficiency of vitamin D in the gestational diabetes group and in control group were 34% and 27% respectively (P<0.0001). There was a significant difference in mean fasting plasma glucose level between gestational diabetes group and healthy pregnant group (P<0.001). There was no relationship between vitamin D levels and body mass index of pregnant women (P=0.1). Conclusion: In this study, the majority of patients had vitamin D deficiency and in the gestational diabetes group, vitamin D deficiency was significantly higher than the control group. The severe deficiency of vitamin D in the gestational diabetes group was higher than patients without gestational diabetes.