Retracted: Effects of vitamin D supplementation on glucose metabolism, lipid concentrations, inflammation, and oxidative stress in gestational diabetes: a double-blind randomized controlled clinical trial
Authors: Teibeh Hashemi
Ahmad Esmaillzadeh
Mansooreh Samimi
Zatollah Asemi
Maryam Karamali
Journal: American Journal of Clinical Nutrition (2013)
Discipline: CLINICAL MEDICINE
Keywords: Vitamin D supplementation; gestational diabetes mellitus; metabolic profiles; high-sensitivity C-reactive protein; oxidative stress
Affiliations: Research Center for Biochemistry and Nutrition in Metabolic Diseases (ZA) and the Department of Gynecology and Obstetrics, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran (TH and MS); the Department of Gynecology and Obstetrics, School of Medicine, Arak University of Medical Sciences, Arak, Iran (MK); and the Food Security Research Center, and the Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran (AE)., Department of Gynecology and Obstetrics, School of Medicine, Kashan University of Medical Sciences, Kashan, Iran, Department of Gynecology and Obstetrics, School of Medicine, Arak University of Medical Sciences, Arak, Iran, Food Security Research Center, and the Department of Community Nutrition, School of Nutrition and Food Science, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract:  Background: To our knowledge, there is no study that has examined the effects of vitamin D supplementation on metabolic status in gestational diabetes mellitus (GDM). Objective: This study was designed to assess the effects of vitamin D supplementation on metabolic profiles, high-sensitivity C-reactive protein, and biomarkers of oxidative stress in pregnant women with GDM. Design: This randomized, double-blind, placebo-controlled clinical trial was conducted in 54 women with GDM. Subjects were randomly assigned to receive either vitamin D supplements or placebo. Individuals in the vitamin D group (n = 27) received capsules containing 50,000 IU vitamin D₃ 2 times during the study (at baseline and at day 21 of the intervention) and those in the placebo group (n = 27) received 2 placebos at the same times. Fasting blood samples were collected at baseline and after 6 wk of the intervention to quantify relevant variables. Results: Cholecalciferol supplementation resulted in increased serum 25-hydroxyvitamin D concentrations compared with placebo (+18.5 ± 20.4 compared with +0.5 ± 6.1 ng/mL; P &lt; 0.001). Furthermore, intake of vitamin D supplements led to a significant decrease in concentrations of fasting plasma glucose (-17.1 ± 14.8 compared with -0.9 ± 16.6 mg/dL; P &lt; 0.001) and serum insulin (-3.08 ± 6.62 compared with +1.34 ± 6.51 μIU/mL; P = 0.01) and homeostasis model of assessment-insulin resistance (-1.28 ± 1.41 compared with +0.34 ± 1.79; P &lt; 0.001) and a significant increase in the Quantitative Insulin Sensitivity Check Index (+0.03 ± 0.03 compared with -0.001 ± 0.02; P = 0.003) compared with placebo. A significant reduction in concentrations of total (-11.0 ± 23.5 compared with +9.5 ± 36.5 mg/dL; P = 0.01) and low-density lipoprotein (LDL) (-10.8 ± 22.4 compared with +10.4 ± 28.0 mg/dL; P = 0.003) cholesterol was also seen after vitamin D supplementation. Conclusions: Vitamin D supplementation in pregnant women with GDM had beneficial effects on glycemia and total and LDL-cholesterol concentrations but did not affect inflammation and oxidative stress. This trial was registered at www.irct.ir as IRCT201305115623N7. 

Retracted: No

PubPeer comments:
 There are many concerns about the integrity of 172 publications by this research group, including this one. Some of the concerns are published 1. Anaesthesia 2020;75:1683u201392, see Supplementary data. This paper is A7 2. Account Res 2020; 28:149-61. 3. J Clin Epidemiol 2021;131:22-29. Journals and publishers were notified of these concerns in July 2019. 23 publications have an expression of concern. To our knowledge there has been no public response about any of the concerns. We think these publications are unreliable , 
 Retracted 8 May 2021 concerns about the validity of participant data in the study ,