Improving the Understanding of the Response to Vitamin D Supplementation

Completed · Phase 3 · Has a placebo group

Conditions studied: Vitamin D Deficiency

In brief

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.

Key facts

Study ID

NCT01465178

Run by

University of Wisconsin, Madison

People needed

62

Starts

2011-12-01

Expected to finish

2014-12-01

Last updated by the study team

2016-11-25

Who can join

Age: 50 and older, up to 100. Sex: female. Healthy volunteers: accepted.

You may qualify if…

• 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

You may not qualify if…

• 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

Where it is running

• University of Wisconsin — Madison, Wisconsin, United States

Full record on ClinicalTrials.gov

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