Vitamin D Deficiency, Insulin Resistance and FGF-23

Study Results

Results available

Outcome measurements, participant flow, baseline characteristics, and adverse events have been published for this study.

View full results

Basic Information

Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.

Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

92 participants

Study Classification

INTERVENTIONAL

Study Start Date

2006-05-31

Study Completion Date

2008-02-29

Brief Summary

Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.

The purpose of this project is to determine if treating vitamin D deficiency decreases insulin resistance and improves insulin secretion in healthy volunteers. Additionally, this project will investigate if treating vitamin D deficiency affects a new phosphate-regulating hormone called FGF-23.

Related Clinical Trials

Explore similar clinical trials based on study characteristics and research focus.

Different Vitamin D Preparations & FGF23 in Humans

NCT00957879

Vitamin D Deficiency

COMPLETED NA

Vitamin D Deficiency in Adolescent Girls

NCT01180946

Healthy Vitamin D Deficiency

COMPLETED NA

Effect of Vitamin D Supplementation in Patients With Heart Failure and Vitamin D Deficiency

NCT02087683

Heart Failure Vitamin D Deficiency

UNKNOWN NA

Effect of Vitamin D Repletion on Insulin Resistance and Systemic Inflammation

NCT01354964

Insulin Resistance

COMPLETED PHASE2

Vitamin D, Insulin Resistance, and Cardiovascular Disease

NCT00736632

Vitamin D Deficiency Insulin Resistance Type 2 Diabetes Mellitus +2 more

COMPLETED NA

Detailed Description

Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.

Vitamin D deficiency or hypovitaminosis D, defined as serum 25 hydroxyvitamin D \< or = 20 ng/mL, is prevalent in several populations in the United States, specifically minorities and the elderly. Causes of vitamin D deficiency include lack of exposure to sunlight, malnutrition, and drugs that alter vitamin D metabolism and absorption.

Vitamin D is an essential factor for many organ systems. Data suggest that vitamin D is required for normal insulin secretion by the pancreas. Specifically, animal studies demonstrate that treatment of vitamin D deficiency improves insulin secretion. In humans, there is less consensus about the impact of vitamin D deficiency on insulin resistance. In one study of middle-aged patients with Type 2 diabetes mellitus, no association was seen between serum 25 hydroxyvitamin D levels and a measure of insulin resistance. However, in a larger study of younger glucose tolerant subjects, serum 25 hydroxyvitamin D levels were associated with both insulin secretion and insulin resistance. These data suggest that treatment of vitamin D deficiency may delay or prevent the development of insulin resistance, and thus diabetes mellitus type 2. Repletion of this common vitamin deficiency could therefore have major public health implications for the prevention of diabetes mellitus.

Fibroblast growth factor 23 (FGF-23) is a newly discovered phosphaturic hormone that is regulated by both dietary and serum phosphate. Hormonal regulation of FGF-23, however, is largely unknown. Recent data suggest that vitamin D plays an important role in the regulation of FGF-23. Some groups have shown that inactivation of the vitamin D receptor gene decreases serum FGF-23 levels in mice; administration of 1,25 dihydroxyvitamin D stimulates the transcription of the FGF-23 gene in vitro. Little is known, however, about the regulation of FGF-23 by vitamin D in humans.

Phosphate is critical for bone mineralization, muscle function, signal transduction, and the creation and utilization of energy. Vitamin D deficiency can result in phosphate malabsorption, osteomalacia and increased risk of fractures. Enhanced understanding of the regulation of this new phosphate-regulating hormone, FGF-23, will advance the field of phosphate metabolism.

Conditions

See the medical conditions and disease areas that this research is targeting or investigating.

Vitamin D Deficiency

Study Design

Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.

Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

TRIPLE

Participants Caregivers Investigators

Study Groups

Review each arm or cohort in the study, along with the interventions and objectives associated with them.

Ergocalciferol group

Ergocalciferol 50000 international units once a week for 12 weeks

Group Type EXPERIMENTAL

Ergocalciferol

Intervention Type DIETARY_SUPPLEMENT

Ergocalciferol 50000 international units once a week for 12 weeks

Ergocalciferol Placebo group

Matching placebo once a week for 12 weeks

Group Type PLACEBO_COMPARATOR

Ergocalciferol placebo

Intervention Type DIETARY_SUPPLEMENT

Ergocalciferol placebo once a week for 12 weeks

Interventions

Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.

Ergocalciferol

Ergocalciferol 50000 international units once a week for 12 weeks

Intervention Type DIETARY_SUPPLEMENT

Ergocalciferol placebo

Ergocalciferol placebo once a week for 12 weeks

Intervention Type DIETARY_SUPPLEMENT

Eligibility Criteria

Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.

Inclusion Criteria

* Age 18 to 45 yrs
* Serum 25-OHD \< or = 20 ng/mL
* At least 1 menses in the last 3 months (females) and normal serum testosterone (males)

Exclusion Criteria

* Significant cardiac, hepatic, oncologic, or psychiatric disease
* History of diabetes mellitus, malabsorption, kidney stones, or recent alcohol excess/abuse (15 drinks per week in the last month)
* Fasting glucose \> 126 mg/dl or 2 hour OGTT \> 200 mg/dl
* Use of medications known to affect serum phosphate levels including phosphate-binding antacids, sodium etidronate, calcitonin, excessive doses of vitamin D (\> 1000 units per day), excessive doses of vitamin A (\> 20,000 units/day), calcitriol, growth hormone, or anti-convulsants
* Use of metformin or insulin sensitizing agents
* Serum calcium \< 8 or \> 11 mg/dL, creatinine \> 1.5 mg/dL, or Hgb \< 11 gm/dL
* Liver function tests \> 2 times the upper limit of normal
* TSH \< 0.1 or \> 7 uU/mL
* WBC \< 2,000 or \> 15,000/cmm
* Platelet count \< 100,000 or \> 500,000/cum
* Hormone replacement therapy or testosterone use
* Urine uhCG positive (females), testosterone \< 270 ng/dL (males)

Minimum Eligible Age

18 Years

Maximum Eligible Age

45 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes