Effects of 6-month vitamin D supplementation on insulin sensitivity and secretion: a randomised, placebo-controlled trial. Issue 3 (September 2019)

• Record Type: Journal Article
• Authors: Lemieux, Patricia; Weisnagel, S John; Caron, Annabelle Z; Julien, Anne-Sophie; Morisset, Anne-Sophie; Carreau, Anne-Marie; Poirier, Jonathan; Tchernof, André; Robitaille, Julie; Bergeron, Jean; Marette, André; Vohl, Marie-Claude; Gagnon, Claudia
• Is Part Of: European journal of endocrinology. Volume 181:Issue 3(2019)
• Page Start: 287
• Page End: 299
• Publication Date: 2019-09
• Subjects: Endocrinology -- Periodicals; 616.4005
• DOI: 10.1530/EJE-19-0156
• Languages: English
• ISSNs: 0804-4643

Abstract

Abstract : Objective: To determine whether vitamin D3 supplementation improves insulin sensitivity, using the hyperinsulinemic-euglycemic clamp. Design: This single-centre, double-blind, placebo-controlled trial randomised 96 participants at high risk of diabetes or with newly diagnosed type 2 diabetes to vitamin D3 5000 IU daily or placebo for 6 months. Methods: We assessed at baseline and 6 months: (1) primary aim: peripheral insulin sensitivity (M-value using a 2-h hyperinsulinemic-euglycemic clamp); (2) secondary aims: other insulin sensitivity (HOMA2%S, Matsuda) and insulin secretion (insulinogenic index, C-peptide area under the curve, HOMA2-B) indices using a 2-h oral glucose tolerance test (OGTT); β-cell function (disposition index: M-value × insulinogenic index); fasting and 2-h glucose post OGTT; HbA1c ; anthropometry. Results: Baseline characteristics were similar between groups (% or mean ± s.d. ): women 38.5%; age 58.7 ± 9.4 years; BMI 32.2 ± 4.1 kg/m 2 ; prediabetes 35.8%; diabetes 20.0%; 25-hydroxyvitamin D (25(OH)D) 51.1 ± 14.2 nmol/L. At 6 months, mean 25(OH)D reached 127.6 ± 26.3 nmol/L and 51.8 ± 16.5 nmol/L in the treatment and placebo groups, respectively ( P < 0.001). A beneficial effect of vitamin D3 compared with placebo was observed on M-value (mean change (95% CI): 0.92 (0.24–1.59) vs −0.03 (−0.73 to 0.67); P = 0.009) and disposition index (mean change (95% CI): 267.0 (−343.4 to 877.4) vs −55.5 (−696.3 to 585.3); P = 0.039) after 6 months. No effect was seen on other outcomes. Conclusions: In individuals at high risk of diabetes or with newly diagnosed type 2 diabetes, vitamin D supplementation for 6 months significantly increased peripheral insulin sensitivity and β-cell function, suggesting that it may slow metabolic deterioration in this population.