Calcium plus vitamin D supplementation influences biomarkers of inflammation and oxidative stress in overweight and vitamin D-deficient women with polycystic ovary syndrome: a randomized double-blind placebo-controlled clinical trial (Publication with Expression of Concern. See FEB, 2023)

Objective This study was conducted to determine the effects of calcium plus vitamin D supplementation on inflammatory factors and biomarkers of oxidative stress among overweight vitamin D-deficient women with polycystic ovary syndrome (PCOS). Design, Patients and Measurements This randomized double- blind placebo-controlled clinical trial was performed among 104 overweight vitamin D-deficient women diagnosed with PCOS aged 18-40 years. Participants were randomly divided into four groups. Group A received 1000 mg calcium daily and vitamin D placebo weekly (N = 26), group B 50000 IU vitamin D weekly and calcium placebo daily (N = 26), group C 1000 mg calcium daily plus 50000 IU vitamin D weekly (N = 26) and group D calcium placebo daily plus vitamin D placebo weekly (N = 26) for 8 weeks. Fasting blood samples were taken at baseline and 8 weeks after intervention to measure inflammatory factors and biomarkers of oxidative stress. Results After 8 weeks, individuals taking calcium plus vitamin D supplements had greater decreases in homoeostatic model assessment beta-cell function (HOMA-B) score (-11.1 vs -8.6, -3.4 and 13.7, respectively, P = 0.03), serum high-sensitivity C-reactive protein (hs-CRP) (-948.3 vs 802.3, -383.8 and 618.2 ng/ml, respectively, P = 0.04) and plasma malondialdehyde (MDA) concentrations (-0.6 vs -0.5, -0.1 and 0.6 mu mol/l, respectively, P = 0.009), and significant increases in plasma total antioxidant capacity (TAC) (35.2 vs 21.1, 22.5 and 153.8 mmol/l, respectively, P = 0.006) and glutathione (GSH) levels (216.0 vs 3.9, -47.5 and -160.8 mu mol/l, respectively, P = 0.001) compared with calcium alone, vitamin D alone and placebo groups. Calcium plus vitamin D cosupplementation did not influence plasma NO and catalase levels. Conclusions We found that calcium plus vitamin D cosupplementation for 8 weeks among overweight and vitamin D-deficient women with PCOS had beneficial effects on inflammatory factor and biomarkers of oxidative stress.