Vitamin D and Osteoporosis Prevention in Elderly African American Women (NIHD)
Vitamin D is a hormone that is produced when sunlight is absorbed by the skin. Vitamin D insufficiency has been recognized as a problem in areas where sun exposure is limited, especially in the wintertime. In addition, the more pigmented the skin is, the less capable it is of utilizing sunlight to make vitamin D. Vitamin D plays an important role in helping the body absorb calcium and in building strong bones. It has also been shown to improve muscle function in the elderly. As we get older, our vitamin D levels in the blood go down and this may increase the risk for falls and fractures. If we can improve vitamin D status as we age, we may be able to improve muscle strength and decrease the risk of falls and fractures.
Determining if Vitamin D Can Decrease Bone Loss and Inhibit the Decline Physical Performance in Elderly African American Women.
Dietary Supplement: Vitamin D 3
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
|Official Title:||Vitamin D and Osteoporosis Prevention in Elderly African American Women: A 4-year Randomized, Double-blind, Placebo-controlled Study to Investigate the Effect of Vitamin D Status in Elderly African American Women|
- 1. To determine if vitamin D supplementation sufficient to raise serum 25(OH)D levels above 75 nmol/L (30 ng/mL) for four years will reduce bone density loss, markers of bone turnover, and serum PTH in elderly black women [ Time Frame: 4 years ] [ Designated as safety issue: No ]2. To determine whether such supplementation will inhibit the decline in physical performance with aging.
- To evaluate the harms of vitamin D intakes that raise 25(OH)D levels above 75 nmol/L for four years in a calcium sufficient population [ Time Frame: 4 years ] [ Designated as safety issue: No ]This research will fill an important gap in knowledge about the potential benefit of vitamin D supplementation in elderly black women. While many experts agree that vitamin D intake should be increased in the elderly, few pertinent studies have included black participants, who represent a vulnerable population due to their low serum 25(OH)D. If vitamin D supplementation proves to be beneficial in this minority group, that would suggest the appropriateness of intake recommendations similar to those proposed for white populations.
|Study Start Date:||August 2010|
|Estimated Study Completion Date:||April 2017|
|Estimated Primary Completion Date:||August 2015 (Final data collection date for primary outcome measure)|
|Placebo Comparator: Placebo||
Experimental: Vitamin D 3
Vitamin D3 will be available in doses of 60, 90, 120, and 150 µg
Dietary Supplement: Vitamin D 3
Patients will bew given a single capsule to take once daily
The long-term goal of this project is to develop strategies for the prevention of osteoporotic fractures in African Americans. Most intervention studies have excluded African Americans because of the erroneous belief that osteoporosis is not a major health problem in this population. In fact, the incidence rate of hip fracture in blacks is 50% of the rate in whites. Since longevity is increasing in the black population, osteoporotic fractures will become an even greater problem for this ethnic minority in the future. Furthermore, morbidity and mortality from osteoporotic fractures is greater in blacks. The elderly require higher intake of vitamin D to prevent bone loss resulting from secondary hyperparathyroidism. Calcium with sufficient vitamin D supplementation may decrease fractures in elderly white populations as a result of reduction in bone loss and falls (improved physical performance). The only fracture intervention study to include African Americans—the Women's Health Initiative—used an inadequate dose of vitamin D (400 IU), a dose unlikely to achieve the vitamin D status proposed by U.S. experts: serum 25 hydroxyvitamin D [25(OH)D] concentration above 75 nmol/L. No calcium/vitamin D intervention studies on fall prevention or physical performance have included African Americans.
As a result of increased skin pigmentation, blacks synthesize less vitamin D from sun exposure. As a result, serum 25(OH)D levels are often in the "insufficient" range. This is accompanied by secondary hyperparathyroidism, but adult blacks have a relative skeletal resistance to PTH, so that they have lower bone turnover. They also have more efficient renal conservation of calcium starting in childhood. Addition of vitamin D3 to a calcium-sufficient African American postmenopausal population does not prevent bone loss. The calcium/vitamin D requirements of black adults may be lower than white adults through midlife. However, the elderly require more vitamin D to produce the higher 25(OH)D levels required to overcome the hyperparathyroidism associated with aging. The skeleton of elderly African Americans appears to be susceptible to the increasing parathyroid hormone levels of old age. Bone loss accelerates and bone turnover markers increase in elderly African Americans just as in whites. The specific aims of this project are to determine if dietary supplementation with calcium/vitamin D will safely reduce bone loss and bone turnover and improve physical performance in elderly African Americans. We will enroll 250 African American women in a four-year vitamin D3 intervention trial where serum 25(OH)D will be maintained at an optimum level above 75 nmol/L. Adequate calcium intake will be ensured. Functional markers of vitamin D including bone density, serum PTH, and bone turnover will be measured. The NIH Conference on Vitamin D and Health in the 21st Century, September 5-6, 2007 concluded that research in this population is a high priority.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01153568
|United States, New York|
|Winthrop University Hospital|
|Mineola, New York, United States, 11501|
|Principal Investigator:||John F. Aloia, MD||Winthrop University Hospital|