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

Sponsor

University of Minnesota (Other)

Overall Status

Completed

CT.gov ID

NCT00749918

Collaborator

Hennepin Healthcare Research Institute (Other)

Enrollment

Location

Arm

Duration (Months)

0.7

Patients Per Site Per Month

Study Details

Study Description

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.

Condition or Disease	Intervention/Treatment	Phase
Prediabetes Vitamin D Deficiency	Dietary Supplement: Cholecalciferol (vitamin D3)	N/A

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.

Study Design

Study Type:

Interventional

Actual Enrollment :

12 participants

Allocation:

Non-Randomized

Intervention Model:

Single Group Assignment

Masking:

None (Open Label)

Primary Purpose:

Prevention

Official Title:

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

Study Start Date :

Jan 1, 2007

Actual Primary Completion Date :

Jun 1, 2008

Actual Study Completion Date :

Jun 1, 2008

Arms and Interventions

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

Arm

Intervention/Treatment

Experimental: 1

Each subject was evaluated and data was collected before and after the intervention

Dietary Supplement: Cholecalciferol (vitamin D3)

Oral capsules of cholecalciferol, 5000 IU/ capsule, two capsules daily for one month.

Other Names:

Cholecalciferol by BIO-TECH Pharmacal, Inc.

Outcome Measures

Primary Outcome Measures

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

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]

Eligibility Criteria

Criteria

Ages Eligible for Study:

18 Years to 65 Years

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

Yes

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