Dose responses of vitamin D3 supplementation on arterial stiffness in overweight African Americans with vitamin D deficiency: A placebo controlled randomized trial
What this study found
Vitamin D3 improved arterial stiffness in a dose-dependent manner, with the largest benefit seen at 4,000 IU/day. Carotid-femoral PWV changed from 6.71 to 6.01 m/s in the 4,000 IU/day group (change -0.70, 95% CI -1.07 to -0.32), compared with 0.02 (-0.34 to 0.38) in the 600 IU/day group and -0.11 (-0.50 to 0.27) in the 2,000 IU/day group; the group-by-time interaction was P<0.01. Carotid-radial PWV also favored the higher dose, with a group-by-time interaction of P=0.03. Serum 25(OH)D increased with dose, and no significant blood pressure changes or adverse events were reported.
- Study & population
- Placebo-controlled randomized trial in overweight African American adolescents and young adults with vitamin D deficiency/suboptimal status (25[OH]D <20 ng/mL), aged 13 to 45 years, conducted in Augusta, Georgia.
- Intervention
- Oral vitamin D3 capsules were given under supervised monthly dosing for 16 weeks at 18,000 IU/month (~600 IU/day), 60,000 IU/month (~2,000 IU/day), or 120,000 IU/month (~4,000 IU/day), with placebo as the comparator.
- Key limitation
- The trial was small, with only 17 to 18 participants per active dose arm, and lasted only 16 weeks.
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Open PDFOriginal abstract
Background Clinical trials are scant and equivocal on whether vitamin D can ameliorate arterial stiffness, particularly in populations at high risk for vitamin D deficiency and cardiovascular disease (CVD). This study determined the dose-response effects of vitamin D3 supplementation on arterial stiffness in overweight African Americans with vitamin D deficiency. Methods Seventy overweight African Americans (aged 13–45 years) with serum 25-hydroxyvitamin D [25(OH)D] levels ≤ 20 ng/mL were randomized to monthly oral supplementation of 18,000 IU (~600 IU/day, n = 17), 60,000 IU (~2000 IU/day, n = 18), or 120,000 IU (~4000 IU/day, n = 18) of vitamin D3 or placebo (n = 17) for 16-weeks. The arterial stiffness measurements, carotid-femoral pulse wave velocity (PWV) and carotid-radial PWV, were assessed by applanation tonometry at baseline and 16 weeks. Results Vitamin D3 supplementation demonstrated a dose-response increase in serum 25(OH)D concentrations between groups (P<0.01). A significant downward linear trend was observed for carotid-femoral PWV (P<0.01), as the mean changes in carotid-femoral PWV across the four treatment groups were 0.13 m/s (95% CI: -0.24, 0.51 m/s) for placebo, 0.02 m/s (95% CI: -0.34, 0.38 m/s) for 600 IU/day group, -0.11 m/s (95% CI: -0.50, 0.27 m/s) for the 2,000 IU/day group, and -0.70 m/s (95% CI: -1.07, -0.32 m/s) for the 4,000 IU/day group. Findings were similar for carotid-radial PWV (P = 0.03), as the mean changes in carotid-radial PWV across the four treatment groups were 0.24 m/s (95% CI: -0.45, 0.92 m/s) for placebo, 0.09 m/s (95% CI: -0.54, 0.73 m/s) for 600 IU/day group, -0.57 m/s (95% CI: -1.20, 0.07 m/s) for the 2,000 IU/day group, and -0.61 m/s (95% CI: -1.25, 0.02 m/s) for the 4,000 IU/day group. Conclusion Arterial stiffness was improved by vitamin D3 supplementation in a dose-response manner in overweight African Americans with vitamin D deficiency.