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The Effect of Vitamin D Repletion on Insulin Resistance

This study has been completed.
Information provided by:
Rockefeller University Identifier:
First received: January 22, 2008
Last updated: October 12, 2011
Last verified: October 2011

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
Dietary Supplement: Vitamin D3 (cholecalciferol)

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Effect of Vitamin D Repletion on Insulin Resistance

Resource links provided by NLM:

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 ]

Estimated Enrollment: 10
Study Start Date: January 2008
Study Completion Date: May 2009
Primary Completion Date: May 2009 (Final data collection date for primary outcome measure)
Intervention Details:
    Dietary Supplement: Vitamin D3 (cholecalciferol)
    Vitamin D will be taken orally, 10,000 IU (0.25 mg) three times per week.

Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

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
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Please refer to this study by its identifier: NCT00606957

United States, New York
Rockefeller University
New York, New York, United States, 10021
Sponsors and Collaborators
Rockefeller University
Principal Investigator: Allegra Grossman, MD The Rockefeller University
  More Information

Responsible Party: Allegra Grossman, MD, The Rockefeller University Identifier: NCT00606957     History of Changes
Other Study ID Numbers: RUH IRB# AGR-0623
Study First Received: January 22, 2008
Last Updated: October 12, 2011

Keywords provided by Rockefeller University:

Additional relevant MeSH terms:
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents processed this record on April 26, 2017