Effect of Vitamin D Supplementation on Oral Glucose Tolerance in Individuals at Risk for Developing Type 2 Diabetes
Year: 2018
Type: dissertation
Study designs: Randomized Controlled Trial, Clinical Trial
Abstract: Vitamin D status is inversely associated with insulin resistance, β-cell dysfunction, and an increased risk for type 2 diabetes (T2D). Clinical trials examining the effect of vitamin D supplementation on various glycemic outcomes and incident T2D have been equivocal. The objectives of this thesis were to determine the effect of weekly vitamin D3 supplementation on oral glucose tolerance, indices of insulin resistance/sensitivity and β-cell function and inflammatory markers in individuals at an increased risk for T2D. We conducted a 24-week, double-blind, randomized, placebo-controlled trial to examine the effect of 28,000 IU of vitamin D3 once weekly on plasma glucose 2 hours after a 75g oral glucose tolerance test (2hPC glucose) and additional glucose-related outcome measures. Seventy-one participants with serum 25-hydroxyvitamin-D [25(OH)D] ≤65 nmol/L, impaired fasting glucose, and/or elevated glycated haemoglobin (HbA1c) were randomly assigned to receive 28,000 IU of vitamin D3 (vitD, n=35) or placebo (n=36) cheese once weekly. The primary outcome was the change in 2hPC glucose. Additional outcomes of interest included fasting glucose, fasting and postprandial insulin, insulin resistance/sensitivity and β–cell function, HbA1c, fasting lipids and inflammatory biomarkers. Participants underwent an oral glucose tolerance test at baseline and week-24. Mean±SD baseline 25(OH)D was 48.1±14.3 and 47.6±14.3 nmol/L in the vitD and placebo groups, respectively; vitamin D3 supplementation increased 25(OH)D to 98.7±36.8 nmol/L (p
Source: TSpace (University of Toronto)
Author: Tracy Moreira‐Lucas
Language: English
Topic: Vitamin D Research Studies
Subfield: Endocrinology, Diabetes and Metabolism
Field: Medicine
Domain: Health Sciences
Open Access status: green
Funder: University of Toronto
OpenAlex ID: W3133719173