Effects of vitamin D supplementation on metabolic and endocrine parameters in healthy premenopausal women: A randomized controlled trial

Abstract

Vitamin D supplementation may affect glycemic as well as hormonal regulation. Thus, the aim of the current study was to investigate whether vitamin D supplementation has any significant effects on metabolic and endocrine parameters in healthy premenopausal women. Primary outcome measure was the plasma glucose area under the curve (AUCgluc). The current study was a single-center, double-blind, randomized placebo-controlled trial that was conducted at the Medical University of Graz, Austria, between March 2013 and October 2017. One-hundred and fifty healthy premenopausal women with 25-hydroxyvitamin D [25(OH)D] concentrations <75nmol/L once weekly received either 20,000 IU of cholecalciferol or placebo (2:1 ratio) over a total of 24 weeks. In total, 127 women [age 36.2±8.7 years; BMI 25.3±5.6kg/m2; baseline 25(OH)D 55.8±19.7nmol/L] completed the study. Vitamin D supplementation had no significant effect on AUCgluc (mean treatment effect 11.70; p=0.069), while it had a significant treatment effect on homeostatic model assessment-insulin resistance (HOMA-IR; mean treatment effect 0.31; p=0.019) and quantitative insulin-sensitivity check index (QUICKI; mean treatment effect-0.019; p=0.013). There was no significant effect on the remaining secondary outcome parameters. In this randomized-controlled trial in healthy premenopausal women, there was a significant treatment effect of vitamin D supplementation on HOMA-IR and QUICKI, while there was no significant treatment effect on AUCgluc.