Personalized Vitamin D Supplementation in European and African Americans
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The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. |
ClinicalTrials.gov Identifier: NCT02362269 |
Recruitment Status :
Completed
First Posted : February 12, 2015
Results First Posted : November 13, 2020
Last Update Posted : December 1, 2020
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Condition or disease | Intervention/treatment | Phase |
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Vitamin D Deficiency | Dietary Supplement: Vitamin D | Not Applicable |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 169 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Double (Participant, Investigator) |
Primary Purpose: | Treatment |
Official Title: | Personalized Vitamin D Supplementation in European and African Americans |
Actual Study Start Date : | October 30, 2015 |
Actual Primary Completion Date : | May 3, 2019 |
Actual Study Completion Date : | May 3, 2019 |

Arm | Intervention/treatment |
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Active Comparator: Control Group
The control group will receive 2500 IU of vitamin D3 daily.
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Dietary Supplement: Vitamin D
Gelcaps containing 1000, 2500, and 4000 IU of vitamin D3 will be obtained from Tischon corporation (Westbury, NY). The gelcaps will be protected from light and not stored above 25° C. Participants will be instructed to take their vitamin D3 gelcaps with supper daily. Compliance with study supplementation will be documented by pill count at the time of each study visits. |
Experimental: Dosing Algorithm Group
The dosing algorithm group will initially receive 1000, 2500, or 4000 IU of vitamin D3 daily based on the baseline 25(OH)D. This group's dosing may be adjusted at the 3-month visit.
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Dietary Supplement: Vitamin D
Gelcaps containing 1000, 2500, and 4000 IU of vitamin D3 will be obtained from Tischon corporation (Westbury, NY). The gelcaps will be protected from light and not stored above 25° C. Participants will be instructed to take their vitamin D3 gelcaps with supper daily. Compliance with study supplementation will be documented by pill count at the time of each study visits. |
- Efficacy of the Dosing Algorithm in Achieving Total 25(OH)D as Measured by the Percentage of Participants Ending With Concentrations of 35-50 ng/mL [ Time Frame: 3 and 6 months ]To validate the proposed vitamin D3 dosing algorithm, a vitamin D panel consisting of serum concentrations of vitamin D3 (cholecalciferol; an indicator of vitamin D3 absorption), 25(OH)D3, 25(OH)D2, the C3-epimer of 25(OH)D3 and 24,25(OH)2D as well as an assay to directly measure free serum 25(OH)D will be run on all the blood samples collected at the baseline, 3 month and 6 month visits.

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Ages Eligible for Study: | Child, Adult, Older Adult |
Sexes Eligible for Study: | Female |
Accepts Healthy Volunteers: | Yes |
Inclusion Criteria:
- Healthy, community-dwelling postmenopausal woman of self-reported European (Madison site) or African (Milwaukee site) descent
- Able and willing to sign informed consent
- Baseline serum 25(OH)D concentration of 10.0-29.9 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 during the months of May through September
Exclusion Criteria:
- Diagnosis of kidney or liver disease (organs that metabolize vitamin D)
- Current hypercalcemia (serum calcium ≥ 10.5 mg/dL) or other disorders that may affect vitamin D metabolism and predispose to hypercalcemia, i.e., sarcoidosis, active tuberculosis or other granulomatous disease.
- Other chronic diseases or conditions potentially affecting vitamin D metabolism or absorption (inflammatory bowel disease, cystic fibrosis, ulcerative colitis, and malabsorptive surgery)
- History of nephrolithiasis
- Current use of medications that affect vitamin D metabolism (glucocorticoids, anticonvulsants, antifungals, and HIV/AIDS medications)
- History of any form of cancer within the past two years with the exception of basal or squamous cell skin lesions, in situ tumors or thyroid cancer
- Terminal illness/on hospice
- Severe end-organ disease (e.g., cardiovascular, pulmonary, etc.), which may limit the ability to complete the study
- 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; current use of multiple vitamins and other vitamin D supplements will be allowed.
- Use of tanning beds or salons or unwillingness to utilize sunscreen during periods of sun exposure of 15 minutes or longer from May through September
- Planned trips/vacations likely to be associated with substantial amounts of sun exposure during the course of the study (i.e., more than 500 miles south of Madison/Milwaukee)

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02362269
United States, Wisconsin | |
University of Wisconsin Osteoporosis Clinical Research Program | |
Madison, Wisconsin, United States, 53705 | |
Medical College of Wisconsin | |
Milwaukee, Wisconsin, United States, 53226 |
Principal Investigator: | Corinne Engelman, PhD | University of Wisconsin, Madison |
Documents provided by University of Wisconsin, Madison:
Responsible Party: | University of Wisconsin, Madison |
ClinicalTrials.gov Identifier: | NCT02362269 |
Other Study ID Numbers: |
2015-0047 A538500 ( Other Identifier: UW Madison ) SMPH\POP HEALTH SCI\POP HLTH ( Other Identifier: UW Madison ) |
First Posted: | February 12, 2015 Key Record Dates |
Results First Posted: | November 13, 2020 |
Last Update Posted: | December 1, 2020 |
Last Verified: | November 2020 |
Vitamin D Deficiency Avitaminosis Deficiency Diseases Malnutrition Nutrition Disorders |
Vitamin D Vitamins Micronutrients Physiological Effects of Drugs Bone Density Conservation Agents |