Improving the Understanding of the Response to Vitamin D Supplementation
It is the investigators hypothesis that the current method of evaluating vitamin D status, measuring circulating 25-hydroxy vitamin D is not providing the full metabolic picture, and is therefore inadequate. The investigators liken this concept to the evolution of cholesterol where initially, total cholesterol was the only measurement, and have since determined the importance of HDL, LDL and triglycerides in evaluating patient status. Similarly, the investigators feel measurement of other vitamin D components such as sulfated vitamin D, circulating vitamin D3 and 3-epi 25-hydroxy vitamin D will offer more comprehensive information about a patient's vitamin D status.
It is our overarching hypothesis that a "vitamin D assay panel," will enhance understanding of vitamin D status. It is our expectation that the enhanced understanding based on improved measurement capability will ultimately translate to improved definition of vitamin D status and need for supplementation on an individual level.
|Vitamin D Deficiency||Dietary Supplement: cholecalciferol Dietary Supplement: Placebo||Phase 3|
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Diagnostic
|Official Title:||Improving the Understanding of the Response to Vitamin D Supplementation|
- Change in Serum 25-hydroxy Vitamin D3 [ Time Frame: Baseline, 1 and 4 months post supplementation ]Our primary outcome variable is the effect of supplementation on change in serum 25(OH)D3;
- Change in Parameters of the Vitamin D Assay Panel [ Time Frame: Baseline, 1 and 4 months post supplementation ]Secondary outcomes are change in cholecalciferol, 24,25(OH)D3 and free 25(OH)D3.
|Study Start Date:||December 2011|
|Study Completion Date:||December 2014|
|Primary Completion Date:||December 2014 (Final data collection date for primary outcome measure)|
Active Comparator: 2000 IU vitamin D3
Cholecalciferol 2,000 IU capsules
Dietary Supplement: cholecalciferol
2000 IU cholecalciferol gelcaps by mouth daily
Placebo Comparator: Placebo
Non-matching placebo, gelatin filled capsules
Dietary Supplement: Placebo
This hypothesis is supported by several observations. First, recent work finds previously unappreciated vitamin D metabolites, notably 3 epi-25(OH)D348 and sulfated 25(OH)D3, in virtually all human sera and circulating in amounts that vary widely between individuals. These compounds may be measured by current "25(OH)D" assays,46, 63 and thereby confound accuracy of such measurements. Secondly, substantial but inadequately understood variability of 25(OH)D response to supplementation and UV exposure exists.15, 42-44 It is likely that currently unappreciated genetic and/or physiologic factors, e.g., differences in absorption or degradation, underpin these observations. Our panel will allow definition of these differences. Finally, the inadequacy of our current approach to classify vitamin D status (singular 25(OH)D measurement) is exemplified by the great between-individual variability in the PTH/25(OH)D relationship as noted above.8, 64 Thus, the investigators believe that exploration of a "vitamin D assay panel," consisting of measurements that reflect input (cholecalciferol and ergocalciferol) and confounders to the 25(OH)D assay [3 epi-25(OH)D and sulfated 25(OH)D] is essential to accurately define optimal vitamin D status and to determine the ideal approach for vitamin D repletion.
To begin testing this hypothesis, the Specific Aims of this research are to document the vitamin D profile response defined as change in serum concentration of:
- 3 epi-25(OH)D
- Sulfated 25(OH)D following four months of supplementation with 2,200 IU of daily vitamin D3 in postmenopausal women. Our primary outcome variable is the effect of supplementation on serum 25(OH)D3; secondary outcomes are change in cholecalciferol, 3 epi-25(OH)D3 and sulfated 25(OH)D3.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01465178
|United States, Wisconsin|
|University of Wisconsin|
|Madison, Wisconsin, United States, 53705|
|Principal Investigator:||Neil Binkley, M.D.||University of Wisconsin, Madison|