A 16-Week Randomized Clinical Trial of 2000 International Units Daily Vitamin D3 Supplementation in Black Youth: 25-Hydroxyvitamin D, Adiposity, and Arterial Stiffness
Journal of Clinical Endocrinology & Metabolism , doi:10.1210/jc.2010-0606
Submitted on March 15, 2010, Accepted on June 14, 2010
Yanbin Dong*, Inger S. Stallmann-Jorgensen, Norman K. Pollock, Ryan A. Harris, Daniel Keeton, Ying Huang, Ke Li, Reda Bassali, De-huang Guo, Jeffrey Thomas, Gary L. Pierce, Jennifer White, Michael F. Holick, and Haidong Zhu
Georgia Prevention Institute, Department of Pediatrics (Y.D., I.S.S.-J., N.K.P., R.A.H., D.K., Y.H., K.L., D.G., J.T., G.L.P., H.Z.); General Pediatrics, Department of Pediatrics (R.B.), and Endocrinology, Department of Medicine (J.W.), Medical College of Georgia, Augusta, Georgia 30912; and Endocrinology, Department of Medicine (M.F.H.), Boston University Medical Center, School of Medicine, Boston, Massachusetts 02118 E-mail: ydong at mail.mcg.edu.
Objective: The aim was to determine 25-hydroxyvitamin D 25(OH)D in response to 2000 IU vitamin D supplementation over time; to evaluate the relation between 25(OH)D concentrations and total body fat mass by dual-energy x-ray absorptiometry; and to determine whether vitamin D supplementation improves arterial stiffness measured by pulse wave velocity (PWV).
Design: We conducted a randomized, blinded, controlled clinical trial.
Setting and Participants: Forty-nine normotensive black boys and girls, aged 16.3 ± 1.4 yr, were randomly assigned to either the control group (400 IU/d; n = 24) or the experimental group (2000 IU/d; n = 25).
Results: Plasma 25(OH)D values at baseline and at 4, 8, and 16 wk were 34.0 ± 10.6, 44.9 ± 9.4, 51.2 ± 11.1, and 59.8 ± 18.2 nmol/liter, respectively, for the control group; and 33.1 ± 8.7, 55.0 ± 11.8, 70.9 ± 22.0, and 85.7 ± 30.1 nmol/liter, respectively, for the experimental group. The experimental group vs. the control group reached significantly higher 25(OH)D concentrations at 8 and 16 wk, respectively. Partial correlation analyses indicated that total body fat mass at baseline was significantly and inversely associated with 25(OH)D concentrations in response to the 2000-IU supplement across time. Furthermore, carotid-femoral PWV increased from baseline (5.38 ± 0.53 m/sec) to posttest (5.71 ± 0.75 m/sec) in the control group (P = 0.016), whereas in the experimental group carotid-femoral PWV decreased from baseline (5.41 ± 0.73 m/sec) to posttest (5.33 ± 0.79 m/sec) (P = 0.031).
Conclusion: Daily 2000 IU vitamin D supplementation may be effective in optimizing vitamin D status and counteracting the progression of aortic stiffness in black youth. Plasma 25(OH)D concentrations in response to the 2000 IU/d supplementation are negatively modulated by adiposity.