Effects of vitamin D2 or D3 supplementation on glycaemic control and cardiometabolic risk among people at risk of type 2 diabetes: results of a randomized double-blind placebo-controlled trial

Diabetes Obes Metab. 2016 Apr;18(4):392-400. doi: 10.1111/dom.12625. Epub 2016 Feb 4.

Abstract

Aims: To investigate the effect of short-term vitamin D supplementation on cardiometabolic outcomes among individuals with an elevated risk of diabetes.

Methods: In a double-blind placebo-controlled randomized trial, 340 adults who had an elevated risk of type 2 diabetes (non-diabetic hyperglycaemia or positive diabetes risk score) were randomized to either placebo, 100,000 IU vitamin D2 (ergocalciferol) or 100,000 IU vitamin D3 (cholecalciferol), orally administered monthly for 4 months. The primary outcome was change in glycated haemoglobin (HbA1c) between baseline and 4 months, adjusted for baseline. Secondary outcomes included: blood pressure; lipid levels; apolipoprotein levels; C-reactive protein levels; pulse wave velocity (PWV); anthropometric measures; and safety of the supplementation.

Results: The mean [standard deviation (s.d.)] 25-hydroxyvitamin D [25(OH)D]2 concentration increased from 5.2 (4.1) to 53.9 (18.5) nmol/l in the D2 group, and the mean (s.d.) 25(OH)D3 concentration increased from 45.8 (22.6) to 83.8 (22.7) nmol/l in the D3 group. There was no effect of vitamin D supplementation on HbA1c: D2 versus placebo: -0.05% [95% confidence interval (CI) -0.11, 0.02] or -0.51 mmol/mol (95% CI -1.16, 0.14; p = 0.13); D3 versus placebo: 0.02% (95% CI -0.04, 0.08) or 0.19 mmol/mol (95% CI -0.46, 0.83; p = 0.57). There were no clinically meaningful effects on secondary outcomes, except PWV [D2 versus placebo: -0.68 m/s (95% CI -1.31, -0.05); D3 versus placebo -0.73 m/s (95% CI -1.42, -0.03)]. No important safety issues were identified.

Conclusions: Short-term supplementation with vitamin D2 or D3 had no effect on HbA1c. The modest reduction in PWV with both D2 and D3 relative to placebo suggests that vitamin D supplementation has a beneficial effect on arterial stiffness.

Keywords: intervention; placebo; pulse wave velocity; randomized; trial; type 2 diabetes; vitamin D2; vitamin D3.

Publication types

  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 25-Hydroxyvitamin D 2 / blood
  • Adult
  • Aged
  • Calcifediol / blood
  • Cardiovascular Diseases / blood
  • Cardiovascular Diseases / epidemiology
  • Cardiovascular Diseases / prevention & control*
  • Cholecalciferol / administration & dosage
  • Cholecalciferol / adverse effects
  • Cholecalciferol / therapeutic use*
  • Cohort Studies
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / epidemiology
  • Diabetes Mellitus, Type 2 / prevention & control*
  • Dietary Supplements* / adverse effects
  • Double-Blind Method
  • England / epidemiology
  • Ergocalciferols / administration & dosage
  • Ergocalciferols / adverse effects
  • Ergocalciferols / therapeutic use*
  • Feasibility Studies
  • Female
  • Follow-Up Studies
  • Glycated Hemoglobin A / analysis
  • Humans
  • Male
  • Middle Aged
  • Pulse Wave Analysis
  • Risk
  • Vascular Stiffness

Substances

  • Ergocalciferols
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human
  • Cholecalciferol
  • 25-Hydroxyvitamin D 2
  • Calcifediol