Vitamin D for the Prevention of Diabetes Type 2

Prevention of Type 2 Diabetes With Vitamin D Supplementation in Subjects With Reduced Glucose Tolerance Detected in the Tromso Study 2007/2008

The prevalence of type 2 diabetes is increasing, which for most societies has considerable consequences not only regarding health but also economy. Type 2 diabetes develops through a "prediabetic" stage with impaired glucose tolerance. Intervention at this stage with change in lifestyle or with medication may prevent such progression. There are indications that vitamin D is of importance in glucose metabolism, and that supplementation with vitamin D may increase both insulin secretion and insulin sensitivity. Accordingly, supplementation with vitamin D may improve glucose tolerance and potentially prevent the development of type 2 diabetes in subjects at risk. However, this has so far not been demonstrated in a prospective, randomised clinical study. In the present study we will therefore include 600 subjects with impaired glucose tolerance (or impaired fasting glucose) detected in the Tromso study 2007/2008 and randomize to supplementation with vitamin D 20.000IU per week or placebo for 5 years. A glucose tolerance test will be performed each year, and development of type 2 diabetes will be the main endpoint.

Oral glucose tolerance response to vitamin D supplementation in relation to polymorphisms in the vitamin D system

The response to oral glucose tolerance test (fasting and 2 h blood glucose, serum insulin, C-peptide, measures of insulin resistiance as well as metabolic parameters (lipids, blood pressure)) will be evaluated in the results at the 1-year visit in relation to genetic polymorphisms in the vitamin D system

Inclusion Criteria: Impaired glucose tolerance Exclusion Criteria: Serious heart disease Renal stone disease Hypercalcemia Sarcoidosis

Jorde R, Sollid ST, Svartberg J, Schirmer H, Joakimsen RM, Njolstad I, Fuskevag OM, Figenschau Y, Hutchinson MY. Vitamin D 20,000 IU per Week for Five Years Does Not Prevent Progression From Prediabetes to Diabetes. J Clin Endocrinol Metab. 2016 Apr;101(4):1647-55. doi: 10.1210/jc.2015-4013. Epub 2016 Feb 1.