Improving the Understanding of the Response to Vitamin D Supplementation
试验速览
- 阶段
- 3 期
- 状态
- 已完成
- 入组人数
- 62
- 试验地点
- 1
- 主要终点
- Change in Serum 25-hydroxy Vitamin D3
研究概览
简要总结
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.
详细描述
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:
- 25(OH)D
- cholecalciferol
- 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.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Diagnostic
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 50 Years 至 100 Years（Adult, Older Adult）
- 性别
- Female
- 接受健康志愿者
- 是
入选标准
- •Healthy, community-dwelling ambulatory postmenopausal White, non-Hispanic women
- •Able and willing to sign informed consent
- •Baseline serum 25(OH)D concentration of 10-29 ng/mL
- •Willing to not alter the amount of their baseline vitamin D supplementation during the course of this study
- •Willing to use sunscreen (SPF ≥15) when sun exposure of > 15 minutes is expected
排除标准
- •Presence of any measurable circulating 25(OH)D2 on screening measurement
- •Current hypercalcemia (serum calcium > 10.5 mg/dl) or untreated primary hyperparathyroidism
- •History of nephrolithiasis
- •Known risk factors for hypercalcemia, e.g., malignancy, tuberculosis, sarcoidosis
- •History of any form of cancer within the past five years with the exception of adequately treated squamous cell or basal cell skin carcinoma
- •Renal failure; defined as a calculated creatinine clearance (using the Cockroft-Gault approach) of ≤ 35 ml/minute
- •Severe end-organ disease, e.g., cardiovascular, hepatic, hematologic, pulmonary, etc., which might limit the ability to complete this study
- •Known metabolic bone disease, e.g., Paget's disease, osteomalacia
- •Treatment with any drug known to interfere with vitamin D metabolism, e.g., phenytoin, phenobarbital
- •Treatment with high dose vitamin D (≥ 50,000 IU weekly) or any active metabolites of vitamin D, e.g., calcitriol, within six months of screening
- •Use of tanning beds or salons or unwillingness to utilize sunscreen during periods of sun exposure of 15 minutes or longer
- •Planned trips/vacations likely to be associated with substantial amounts of sun exposure during the course of the study
研究组 & 干预措施
Placebo
Non-matching placebo, gelatin filled capsules
干预措施: Placebo (Dietary Supplement)
2000 IU vitamin D3
Cholecalciferol 2,000 IU capsules
干预措施: cholecalciferol (Dietary Supplement)
结局指标
主要结局
Change in Serum 25-hydroxy Vitamin D3
时间窗: Baseline, 1 and 4 months post supplementation
Our primary outcome variable is the effect of supplementation on change in serum 25(OH)D3;
次要结局
- Change in Parameters of the Vitamin D Assay Panel(Baseline, 1 and 4 months post supplementation)