Vitamin D Inadequacy, Vitamin D Deficiency
Conditions
Brief summary
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.
Interventions
DIETARY_SUPPLEMENTCholecalciferol (vitamin D3)
50,000 IU once monthly for 12 months
DIETARY_SUPPLEMENTErgocalciferol (vitamin D2)
oral capsule 50,000 IU once monthly for 12 months
DIETARY_SUPPLEMENTPlacebo
oral placebo capsule once daily for 12 months
Sponsors
University of Wisconsin, Madison
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
65 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
1. Community dwelling men and women age ≥ 65 years. 2. Able and willing to sign informed consent. 3. Serum 25OHD concentration ≥ 10 and less than 60 ng/ml by HPLC. 4. 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
Exclusion criteria
1. Current hypercalcemia (serum calcium \> 10.5 mg/dl) or untreated primary hyperparathyroidism. 2. History of nephrolithiasis. 3. Screening 25OHD concentration ≥ 60 ng/ml. 4. Baseline 24-hour urine calcium \> 250 mg if female, \> 300 mg if male. 5. Known risk factors for hypercalcemia, e.g., malignancy, tuberculosis, sarcoidosis, Paget's disease 6. History of any form of cancer within the past five years with the exception of adequately treated squamous cell or basal cell skin cancer. 7. Renal failure defined as a calculated creatinine clearance (Cockroft-Gault method) ≤ 25 ml/minute 8. Severe end-organ disease, e.g., cardiovascular, hepatic, hematologic, pulmonary, etc., which may limit ability to complete the study 9. Known malabsorption syndromes, e.g., celiac disease, radiation enteritis, active inflammatory bowel disease, etc. 10. Use of medications known to alter bone turnover including bisphosphonates, estrogen, selective estrogen receptor modulators, PTH, testosterone or calcitonin 11. Vitamin D intake greater than 5,000 IU daily 12. Treatment with any active metabolites of vitamin D within six months of screening 13. Treatment with any drug which may interfere with vitamin D metabolism, e.g., phenobarbital, phenytoin.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| The primary outcome measure is change in 25OHD with various D2 and D3 dosing regimens. | 12 months |
Secondary
| Measure | Time frame |
|---|---|
| Determine whether once monthly vitamin D2 or D3 dosing is as effective as daily dosing in attainment, and subsequent maintenance, of 25OHD status | 12 months |
| Delineate the effect of these vitamin D regimens on other parameters of skeletal relevance | 12 months |
Countries
United States
Outcome results
None listed