Effects of vitamin D supplementation on glycaemic control and lipid profiles in gestational diabetes mellitus: a Meta-analysis of randomized controlled trials

Objective To systematically evaluate the effects of vitamin D supplementation on glucose homeostasis parameters and lipid profiles in gestational diabetes patients. Methods Four main databases including PubMed, Web of Science, CNKI and Wanfang were searched to collect randomized controlled trials (RCTs) about vitamin D supplementation for gestational diabetes mellitus from inception to February 1, 2018.Two investigators were chosen to search, extract and evaluate the data independently. Software RevMan 5.3 and Stata 15.0 were used for meta-analysis. Results Results A total of 6 randomized RCTs were included including 409 patients totally which were divided into two groups as study group(n=204) and control group(n=205). The results showed that compared with the control group, patients in study group had lower fasting plasma glucose(FPG)[MD=-11.43, 95% CI=(-15.24-7.61), P=0.000 01], fasting insulin(FIns)[MD=-4.8, 95% CI=(-5.99, 3.62), P<0.000 01], insulin homeostasis model assessment of insulin resistance(HOMA-IR)[MD=-1.48, 95% CI=(-1.81, 1.16), P<0.000 01], total-cholesterol(TC)[MD=-14.09, 95% CI=(-22.09, 5.2), P=0.002], low-density lipoprotein(LDL)[MD=-10.54, 95% CI=(-18.18, 2.89), P=0.007] and high-density lipoprotein(HDL)[MD=2.11, 95% CI=(0.36, 3.86), P=0.02]. No significant difference was found in triglycerides level(TG) between the two groups. Conclusion Vitamin D supplementation in patients with gestational diabetes can improve FPG, insulin, TC, LDL, insulin resistance and HDL, but has no effect on TG. Key words: Vitamin D; Gestational diabetes mellitus; Meta-analysis; Randomized controlled trials