Vitamin D Supplementation Requirement in Obese Subjects

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00996866
Recruitment Status : Completed
First Posted : October 16, 2009
Last Update Posted : December 15, 2014
Information provided by (Responsible Party):
Winthrop University Hospital

October 15, 2009
October 16, 2009
December 15, 2014
December 2008
June 2011   (Final data collection date for primary outcome measure)
Mean level of 25(OH)D during calorie restricted weight loss from the placebo group. [ Time Frame: baseline and at 8 weeks ]
Same as current
Complete list of historical versions of study NCT00996866 on Archive Site
Dose response curve (the 'slope' i.e. the ratio of ∆ 25(OH)D/ initial vitamin D3 dose) in vitamin D supplemented group. [ Time Frame: 8 weeks ]
Same as current
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Vitamin D Supplementation Requirement in Obese Subjects
Vitamin D Supplementation Requirement in Obese Subjects
Vitamin D deficiency is common in obese patients. Most of vitamin D supplementation studies were done with non-obese subjects. This study looks at vitamin D supplementation requirements in obese patients as compared to non-obese subjects. This study also looks at changes in vitamin D level in obese patients undergoing medical weight loss. It is thought that obese patients have vitamin D deficiency through storage of vitamin D in the fat compartment not readily available for blood measurement. The investigators' hypothesis is that with medical weight loss vitamin D levels will increase in obese subjects.

We intend to study changes in serum 25(OH)D level with calorie restricted weight loss in obese subjects. This will be a double dummy, placebo controlled randomized trial. Subjects whose serum 25(OH)D level is below 80 nmol/L will be assigned randomly to either the vitamin D supplemented or the placebo group. Those who are assigned to the placebo group will be weighed on a weekly basis and serum 25(OH)D level will be followed every 8 weeks for a minimum of 16 weeks and extended to the duration of weight loss along with serum calcium level. Changes in serum 25(OH)D level will be obtained with weight loss through restricted caloric intake.

To study the 25(OH)D dose-response curve with vitamin D supplementation in obese subjects, vitamin D supplemented group will receive initial daily vitamin D3 supplementation dose based on their baseline serum 25(OH)D level as described in Methods and Procedures section. Serum 25(OH)D levels will be drawn at 8 weeks and adjustments to the dose will be made based on the an algorithm to achieve serum 25(OH)D levels between 80 and 140 nmol/L. The dose-response curve obtained at 8 weeks will be compared to the one already established with non-obese subjects. Serum 25(OH)D level will be obtained at 16 weeks and compared with the data available from non-obese subjects.

Not Applicable
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary Purpose: Treatment
Vitamin D Deficiency
  • Drug: Vitamin D3
    Vitamin D supplementation will follow an algorithm for initial vitamin D dosing and for dose changes. Subjects will receive 100 ug/day of vitamin D3 if their 25(OH)D level is less than 50nmol/L and 50 ug/day if their 25(OH)D level is between 50 and 80 ug/day.
  • Drug: placebo
    The placebo group will receive sugar pills appearing similar to the vitamin D capsules.
  • Placebo Comparator: Placebo
    Half of subjects will be randomized to the placebo group.
    Intervention: Drug: placebo
  • Active Comparator: Vitamin D3
    This is the study group that receives Vitamin D supplementation.
    Intervention: Drug: Vitamin D3
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*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
August 2011
June 2011   (Final data collection date for primary outcome measure)

Inclusion Criteria:

  • Healthy men or women between the ages of 18 and 70 years old who are enrolled in our Weight Management Program with baseline BMI > 30 Kg/m2.

Exclusion Criteria:

  • Pregnancy,
  • Serum 25(OH)D level greater than 80 nmol/L,
  • Hypercalcemia (serum calcium level greater than the upper limit of normal),
  • Recent surgery or illness,
  • Those with chronic use of medications that influence calcium/vitamin D metabolism such as anti-convulsants, lithium and steroids. Thiazide diuretics for hypertension will be acceptable.
  • Subjects with sarcoidosis will be excluded.
  • Those who do not qualify to participate in the Weight Management Program will be excluded. They include subjects with active substance abuse and unstable cardiac disease.
Sexes Eligible for Study: All
18 Years to 65 Years   (Adult)
Contact information is only displayed when the study is recruiting subjects
United States
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Not Provided
Winthrop University Hospital
Winthrop University Hospital
Not Provided
Principal Investigator: John Aloia,, MD Winthrop-Unviersity Hospital
Winthrop University Hospital
December 2014

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP