Clinical Approaches to Correcting Vitamin D Inadequacy and Maintaining Adequacy

Completed · Not applicable · Has a placebo group

Conditions studied: Vitamin D Inadequacy, Vitamin D Deficiency

In brief

Vitamin D is available in two forms, vitamin D2 and vitamin D3. It has previously been assumed that these two forms maintain blood vitamin D equally. However, this may not be the case. This study will evaluate whether D2 and D3 produce equal elevation of blood vitamin D. Additionally, it will evaluate whether once per month vitamin D dosing is as effective in maintaining blood vitamin D levels as daily dosing.

Key facts

Study ID

NCT00692120

Run by

University of Wisconsin, Madison

People needed

64

Starts

2007-02-01

Expected to finish

2008-11-01

Last updated by the study team

2015-10-05

Who can join

Age: 65 and older. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• Community dwelling men and women age ≥ 65 years.
• Able and willing to sign informed consent.
• Serum 25OHD concentration ≥ 10 and less than 60 ng/ml by HPLC.
• Willing to avoid use of cod-liver oil and non-study vitamin D supplementation; standard multiple vitamins containing ≤ 400 IU used no more than once daily will be allowed

You may not qualify if…

• Current hypercalcemia (serum calcium > 10.5 mg/dl) or untreated primary hyperparathyroidism.
• History of nephrolithiasis.
• Screening 25OHD concentration ≥ 60 ng/ml.
• Baseline 24-hour urine calcium > 250 mg if female, > 300 mg if male.
• Known risk factors for hypercalcemia, e.g., malignancy, tuberculosis, sarcoidosis, Paget's disease
• History of any form of cancer within the past five years with the exception of adequately treated squamous cell or basal cell skin cancer.
• Renal failure defined as a calculated creatinine clearance (Cockroft-Gault method) ≤ 25 ml/minute
• Severe end-organ disease, e.g., cardiovascular, hepatic, hematologic, pulmonary, etc., which may limit ability to complete the study
• Known malabsorption syndromes, e.g., celiac disease, radiation enteritis, active inflammatory bowel disease, etc.
• Use of medications known to alter bone turnover including bisphosphonates, estrogen, selective estrogen receptor modulators, PTH, testosterone or calcitonin
• Vitamin D intake greater than 5,000 IU daily
• Treatment with any active metabolites of vitamin D within six months of screening
• Treatment with any drug which may interfere with vitamin D metabolism, e.g., phenobarbital, phenytoin.

Where it is running

• UW Osteoporosis Clinical and Research Program — Madison, Wisconsin, United States

Full record on ClinicalTrials.gov

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