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.
|Study Design:||Allocation: Randomized
Endpoint Classification: Pharmacokinetics/Dynamics Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator)
Primary Purpose: Treatment
|Official Title:||Vitamin D Supplementation Requirement in Obese Subjects|
- Mean level of 25(OH)D during calorie restricted weight loss from the placebo group. [ Time Frame: baseline and at 8 weeks ] [ Designated as safety issue: Yes ]
- 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 ] [ Designated as safety issue: Yes ]
|Study Start Date:||December 2008|
|Study Completion Date:||August 2011|
|Primary Completion Date:||June 2011 (Final data collection date for primary outcome measure)|
Placebo Comparator: Placebo
Half of subjects will be randomized to the placebo group.
The placebo group will receive sugar pills appearing similar to the vitamin D capsules.
Active Comparator: Vitamin D3
This is the study group that receives Vitamin D supplementation.
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.
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.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00996866
|United States, New York|
|Winthrop University Hospital|
|Mineola, New York, United States, 11501|
|Principal Investigator:||John Aloia,, MD||Winthrop-Unviersity Hospital|