A randomized trial of vitamin D₃ supplementation in children: dose-response effects on vitamin D metabolites and calcium absorption
| Autor: | R D, Lewis, E M, Laing, K M, Hill Gallant, D B, Hall, G P, McCabe, D B, Hausman, B R, Martin, S J, Warden, M, Peacock, C M, Weaver |
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| Rok vydání: | 2013 |
| Předmět: |
Male
Indiana Georgia Adolescent Endocrine Care Vitamin D Deficiency Models Biological White People Black or African American Calcium Dietary Child Development Calcitriol Double-Blind Method Intestinal Absorption Parathyroid Hormone Dietary Supplements Sunlight Humans Female Seasons Child Calcifediol Cholecalciferol |
| Zdroj: | The Journal of Clinical Endocrinology and Metabolism |
| ISSN: | 1945-7197 |
| Popis: | Context: Changes in serum vitamin D metabolites and calcium absorption with varying doses of oral vitamin D3 in healthy children are unknown. Objective: Our objective was to examine the dose-response effects of supplemental vitamin D3 on serum vitamin D metabolites and calcium absorption in children living at two U.S. latitudes. Design: Black and white children (n = 323) participated in a multisite (U.S. latitudes 34° N and 40° N), triple-masked trial. Children were randomized to receive oral vitamin D3 (0, 400, 1000, 2000, and 4000 IU/d) and were sampled over 12 weeks in winter. Serum 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) were measured using RIA and intact PTH (iPTH) by immunoradiometric assay. Fractional calcium absorption was determined from an oral stable isotope 44Ca (5 mg) in a 150-mg calcium meal. Nonlinear and linear regression models were fit for vitamin D metabolites, iPTH, and calcium absorption. Results: The mean baseline 25(OH)D value for the entire sample was 70.0 nmol/L. Increases in 25(OH)D depended on dose with 12-week changes ranging from −10 nmol/L for placebo to 76 nmol/L for 4000 IU. Larger 25(OH)D gains were observed for whites vs blacks at the highest dose (P < .01). Gains for 1,25(OH)2D were not significant (P = .07), and decreases in iPTH were not dose-dependent. There was no dose effect of vitamin D on fractional calcium absorption when adjusted for pill compliance, race, sex, or baseline 25(OH)D. Conclusion: Large increases in serum 25(OH)D with vitamin D3 supplementation did not increase calcium absorption in healthy children living at 2 different latitudes. Supplementation with 400 IU/d was sufficient to maintain wintertime 25(OH)D concentrations in healthy black, but not white, children. |
| Databáze: | OpenAIRE |
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