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Dose response to vitamin D supplementation in African Americans: results of a 4-arm, randomized, placebo-controlled trial.
- Source :
-
The American journal of clinical nutrition [Am J Clin Nutr] 2014 Mar; Vol. 99 (3), pp. 587-98. Date of Electronic Publication: 2013 Dec 24. - Publication Year :
- 2014
-
Abstract
- Background: Association studies have suggested that lower circulating 25-hydroxyvitamin D [25(OH)D] in African Americans may partially underlie higher rates of cardiovascular disease and cancer in this population. Nonetheless, the relation between vitamin D supplementation and 25(OH)D concentrations in African Americans remains undefined.<br />Objective: Our primary objective was to determine the dose-response relation between vitamin D and plasma 25(OH)D.<br />Design: A total of 328 African Americans in Boston, MA, were enrolled over 3 winters from 2007 to 2010 and randomly assigned to receive a placebo or 1000, 2000, or 4000 IU vitamin D₃/d for 3 mo. Subjects completed sociodemographic and dietary questionnaires, and plasma samples were drawn at baseline and 3 and 6 mo.<br />Results: Median plasma 25(OH)D concentrations at baseline were 15.1, 16.2, 13.9, and 15.7 ng/mL for subjects randomly assigned to receive the placebo or 1000, 2000, or 4000 IU/d, respectively (P = 0.63). The median plasma 25(OH)D concentration at 3 mo differed significantly between supplementation arms at 13.7, 29.7, 34.8, and 45.9 ng/mL, respectively (P < 0.001). An estimated 1640 IU vitamin D₃/d was needed to raise the plasma 25(OH)D concentration to ≥ 20 ng/mL in ≥ 97.5% of participants, whereas a dose of 4000 IU/d was needed to achieve concentrations ≥ 33 ng/mL in ≥ 80% of subjects. No significant hypercalcemia was seen in a subset of participants.<br />Conclusions: Within African Americans, an estimated 1640 IU vitamin D₃/d was required to achieve concentrations of plasma 25(OH)D recommended by the Institute of Medicine, whereas 4000 IU/d was needed to reach concentrations predicted to reduce cancer and cardiovascular disease risk in prospective observational studies. These results may be helpful for informing future trials of disease prevention.
- Subjects :
- Adult
Black or African American
Aged
Aged, 80 and over
Boston epidemiology
Cardiovascular Diseases epidemiology
Cardiovascular Diseases ethnology
Cardiovascular Diseases etiology
Cholecalciferol administration & dosage
Cholecalciferol adverse effects
Cohort Studies
Double-Blind Method
Female
Humans
Intention to Treat Analysis
Lost to Follow-Up
Male
Middle Aged
Neoplasms epidemiology
Neoplasms ethnology
Neoplasms etiology
Patient Dropouts
Risk Factors
Seasons
Vitamin D Deficiency blood
Vitamin D Deficiency ethnology
Vitamin D Deficiency physiopathology
Calcifediol blood
Cardiovascular Diseases prevention & control
Cholecalciferol therapeutic use
Dietary Supplements adverse effects
Neoplasms prevention & control
Vitamin D Deficiency diet therapy
Subjects
Details
- Language :
- English
- ISSN :
- 1938-3207
- Volume :
- 99
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The American journal of clinical nutrition
- Publication Type :
- Academic Journal
- Accession number :
- 24368437
- Full Text :
- https://doi.org/10.3945/ajcn.113.067777