Background: Vitamin D deficiency is common in pregnancy, leading to increase in the frequency of preeclampsia, cesarean delivery, neonatal bacterial vaginosis, and gestational diabetes. The current study was designed and implemented to investigate the effect of vitamin D during the first and second trimesters of pregnancy in reducing the risk of gestational diabetes mellitus (GDM) in women who are at high risk [history of GDM, birth macrosomia, family history, and high body mass index (BMI)]. Materials and Methods: In a randomized, double-blind, and placebo-controlled trial, 90 pregnant women who had at least one risk factor for GDM were randomized into intervention (46 participants) and control (44 participants) groups. Participants in the intervention group took 5000 units of vitamin D daily and the control group took placebo until the 26th week of pregnancy. Then the glucose challenge test (GCT) and the glucose tolerance test (GTT) were performed to evaluate GDM. Results: Mean ± standard deviation (SD) age was 31.28 ± 6.38 years and 29 ± 6.24 years for the intervention group and the placebo group, respectively, (P > 0.05). In addition, there were no significant differences between two groups in terms of vitamin D levels and GCT (P > 0.05), and the difference was not significant. The incidence of diabetes in the intervention groups was statistically lower than in control group (11.4% vs 34.8; P < 0.01). The results showed that abnormal GCT in the placebo group was statistically higher than in intervention group (35.9% vs 10.9 P < 0.005). Conclusion: The results of the current study showed that the prescription of vitamin D supplementation in the first and second trimesters of pregnancy was effective in reducing GDM and controlling GTT and GTC.

Background: The prevalence of vitamin D deficiency is higher in end-stage renal disease (ESRD) patients compared to healthy populations. This deficiency could lead to several complications with different mechanisms and might result in reduced survival in patients. Leptin and adiponectin are messenger proteins with endocrine secretion from adipocytes and various effects in cellular mechanisms. The goal of this study was to find the effect of vitamin D administration on serum levels of leptin and adiponectin in ESRD patients. Materials and Methods: This double-blind randomized placebo-controlled clinical trial was carried out on 64 ESRD patients on hemodialysis in the Amin and Noor hospitals of Isfahan, Iran. Patients were categorized into two groups, on control and intervention; serum levels of vitamin D, leptin, and adiponectin were measured in both groups before and after the study. The intervention group was treated with vitamin D pearls, while the control group received placebo in the same manner. Results: The mean [standard deviation (SD)] ages of the patients were 62 (21) years and 60 (19) years in the control and treated groups, respectively. Conclusion: The change in serum level of vitamin D was statistically significant in the treatment group but not in the control group. The serum level of leptin was reduced in the treatment group, while the serum level of adiponectin increased significantly, but none of these changes were statistically significant in the control group. This study showed that vitamin D administration is associated with an increase in adiponectin and a decrease in leptin level in ESRD patients.