The Effect of Vitamin D Repletion on Insulin Resistance - Full Text View

Sponsored by:	Rockefeller University
Information provided by:	Rockefeller University
ClinicalTrials.gov Identifier:	NCT00606957

Purpose

The reason for doing this study is to learn whether raising a person's vitamin D level from below normal to normal levels will improve his or her body's ability to use sugar. Vitamin D is well known to be an important vitamin for the development and maintenance of bones. Recently, scientists have learned that vitamin D may have a role in the prevention of cancer, diabetes, and autoimmune diseases. The investigators are specifically interested in studying this question in the overweight/obese population as they are at greater risk for both vitamin D deficiency and impaired ability to metabolize sugar (glucose intolerance).

Primary Hypotheses:

Vitamin D repletion (increasing the serum 25(OH)D level from ≤ 20 ng/ml to ≥ 30 ng/ml) will improve insulin sensitivity in individuals who are overweight/obese and insulin resistant.

Secondary Hypotheses:

1.Vitamin D repletion will improve biomarkers of cardiovascular risk and inflammation (directly altering macrophage cytokine production and/or indirectly as a result of improvement in insulin sensitivity.) 2.30,000 IU (0.25 mg) weekly of cholecalciferol (vitamin D3) will raise serum 25(OH)D levels from ≤ 20 ng/ml to ≥ 30 ng/ml overweight/obese population.

Condition	Intervention
Obesity	Dietary Supplement: Vitamin D3 (cholecalciferol)

MedlinePlus related topics: Obesity

Drug Information available for: Ergocalciferol Cholecalciferol Insulin Vitamin D

U.S. FDA Resources

Study Type:	Interventional
Study Design:	Treatment, Open Label, Active Control, Single Group Assignment
Official Title:	The Effect of Vitamin D Repletion on Insulin Resistance

Further study details as provided by Rockefeller University:

Primary Outcome Measures:

The primary outcome is change in insulin sensitivity over time, as measured by the glucose clamp, HOMA and OGTT. [ Time Frame: 14 weeks ] [ Designated as safety issue: No ]

Estimated Enrollment:	10
Study Start Date:	January 2008
Estimated Primary Completion Date:	February 2009 (Final data collection date for primary outcome measure)

Intervention Details:

Vitamin D will be taken orally, 10,000 IU (0.25 mg) three times per week.

Eligibility

Ages Eligible for Study:	18 Years to 65 Years
Genders Eligible for Study:	Both
Accepts Healthy Volunteers:	Yes

Criteria

Inclusion Criteria:

Nonsmoking men and women, ages 18-65
Body mass index (BMI) ≥ 28 kg/m² and within 10% of maximum weight
Serum 25(OH)D level ≤ 20 ng/ml
Serum insulin level ≥ 7.2 mU/l
Willingness to maintain current body weight for the duration of the study
Willingness to maintain baseline lifestyle activities and routines for the duration of the study
Willingness to avoid the use of non-steroidal anti-inflammatory drugs (NSAIDS), including low-dose daily aspirin, for at least ten days prior to each admission (due to the potential effects of these agents on inflammatory markers.)
Willingness to avoid the use of all over-the-counter or prescription vitamins, dietary supplements, and herbal products during the study, with the exception of a basic multivitamin supplement.
If of childbearing potential, willingness to use highly effective contraception for the duration of the study.

Exclusion Criteria:

Current tobacco smoking
History of bleeding or coagulation disorders
Gastrointestinal disease resulting in significant gastrointestinal dysfunction or malabsorption
History of diabetes, or diagnosed during screening OGTT
Current treatment with hypertensive medications
History of cardiovascular disease
Renal disease, as evidenced by a serum creatinine above the upper limit of normal on more than one screening visit
History of kidney stones
History of chronic hepatitis, or liver enzymes (AST or ALT) more than 2.5 times the upper limit of normal
Primary hyperparathyroidism or baseline hypercalcemia from any cause
Current treatment with over-the-counter or prescription weight loss medications, such as orlistat or sibutramine
History of bariatric surgery
Current treatment with any cholesterol-lowering medications, such as statins, niacin, fibrates, or ezetimibe
Blood pressure ≥ 145/90 after ten minutes of rest on more than one screen visit
Hyperthyroidism or untreated hypothyroidism. Subjects with chronic, treated, stable hypothyroidism may be included in the study at the discretion of the Principal Investigator.
Pregnancy, desired pregnancy, or lactation within the study period.
HIV, Hepatitis B and C
Medical conditions requiring daily calcium supplementation or antacid use
Use of medications known to interact with calcium or vitamin D metabolism (bisphosphonates, corticosteroids, thiazide diuretics, cholestyramine, colestipol, mineral oil, phenytoin, barbituates, dititalis glycosides, antacids)
Subjects with known hypersensitivity to cholecalciferol
Participation in an investigational drug study within one month of screening
History, physical, or laboratory findings suggestive of any other medical or psychological condition that would, in the opinion of the principal investigator, make the candidate ineligible for the study

Contacts and Locations

Please refer to this study by its ClinicalTrials.gov identifier: NCT00606957

Locations

United States, New York
Rockefeller University
New York, New York, United States, 10021

Sponsors and Collaborators

Rockefeller University

Investigators

Principal Investigator:

Allegra Grossman, MD

The Rockefeller University

More Information

Related Info This link exits the ClinicalTrials.gov site

Responsible Party:	The Rockefeller University ( Allegra Grossman, MD )
Study ID Numbers:	RUH IRB# AGR-0623
Study First Received:	January 22, 2008
Last Updated:	July 1, 2008
ClinicalTrials.gov Identifier:	NCT00606957
Health Authority:	United States: Food and Drug Administration

Keywords provided by Rockefeller University:

Obesity
Metabolism

Study placed in the following topic categories:

Cholecalciferol
Obesity
Metabolic Diseases
Ergocalciferols
Overweight
Insulin
Body Weight
Hyperinsulinism

Signs and Symptoms
Vitamin D
Nutrition Disorders
Overnutrition
Insulin Resistance
Glucose Metabolism Disorders
Metabolic disorder

Additional relevant MeSH terms:

Growth Substances
Vitamins
Physiological Effects of Drugs

Bone Density Conservation Agents
Micronutrients
Pharmacologic Actions

ClinicalTrials.gov processed this record on February 11, 2009