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

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

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT00749918

Enrollment

Registered

2008-09-09

Start date

2007-01-31

Completion date

2008-06-30

Last updated

2008-10-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Prediabetes, Vitamin D Deficiency

Keywords

vitamin D, Cholecalciferol, Insulin sensitivity, MinMod Millennium, FSIGT, modified frequently sampled IV glucose tolerance test

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.

Interventions

DIETARY_SUPPLEMENTCholecalciferol (vitamin D3)

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

Study design

Allocation

NON_RANDOMIZED

Intervention model

SINGLE_GROUP

Primary purpose

PREVENTION

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

18 Years to 65 Years

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

Design outcomes

Primary

Measure	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

Measure	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

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026