Effect of Vitamin D Deficiency and Vitamin D Supplementation on Glucose Metabolism

Study Overview
=================
Brief Summary
-----------------
This study was intended to evaluate the effect of vitamin D supplementation on insulin sensitivity and pancreatic islet beta-cell function. Our hypothesis was that vitamin D supplementation to normal levels in patients with impaired fasting glucose will result in improved insulin sensitivity and improved beta cell function.

Detailed Description
-----------------
A modified frequently sampled intravenous glucose tolerance (mFSIGT) test was used. On day 0, baseline 22 time point mFSIGT was performed. Subjects were then treated with cholecalciferol (vitamin D3) supplementation - 10,000 IU/day - for 28 consecutive days. mFSIGT was then repeated measuring glucose, insulin and c-peptide at all time points. 25-OH vitamin D, PTH, and calcium were also measured at time point 0 pre and post vitamin D supplementation. Data was analyzed using the Bergman/Boston minimal model for insulin homeostasis with MinMod Millennium software.

Official Title
-----------------
Improved Insulin Sensitivity With Therapeutic Vitamin D Replacement in Pre-Diabetic Vitamin D Deficient Individuals

Conditions
-----------------
Prediabetes, Vitamin D Deficiency

Intervention / Treatment
-----------------
* Dietary Supplement: Cholecalciferol (vitamin D3)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Impaired fasting glucose Adult, age between 18 and 65 Serum vitamin D level below 30 ng/mL Exclusion Criteria: History of nephrolithiasis Any medications that can effect insulin sensitivity or beta cell function (i.e. antipsychotics, metformin) Pregnancy Liver disease Renal disease

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: 1<br>Each subject was evaluated and data was collected before and after the intervention | Dietary Supplement: Cholecalciferol (vitamin D3)<br>* Oral capsules of cholecalciferol, 5000 IU/ capsule, two capsules daily for one month.<br>* Other names: Cholecalciferol by BIO-TECH Pharmacal, Inc.;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Assessment of insulin sensitivity before and after oral vitamin D3 supplementation with 10,000 IU/day for one month. |  | At baseline and after 4 weeks of vitamin D supplementation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Monitor effect of vitamin D supplementation with 10,000 IU/day for one month on serum calcium and parathyroid hormone levels. |  | One month | 
| Assess effect of vitamin D supplementation on beta cell function as measured by analysis of data collected through a modified FSIGT test. |  | One month | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
vitamin D, Cholecalciferol, Insulin sensitivity, MinMod Millennium, FSIGT, modified frequently sampled IV glucose tolerance test