Abstract
OBJECTIVE: There has been no prospective study that examined intramuscular injection of high-dose vitamin D in Korean adults. The aim of this study was to assess the efficacy and safety of high-dose vitamin D(3) after intramuscular injection in Korean adults with vitamin D deficiency. METHOD: This study was a 24-week, prospective, multicenter, randomized, double-blind, placebo-controlled trial. A total of 84 subjects ≥19 and <65 years of age were randomly allocated to either the vitamin D(3) or placebo group in a 2:1 ratio. After randomization, a single injection of plain vitamin D(3) 200,000 IU or placebo was intramuscularly administered. If serum 25-hydroxyvitamin D (25[OH]D) concentrations were <30 ng/mL on week 12 or thereafter, a repeat injection was administered. RESULTS: After a single intramuscular injection of vitamin D(3) to adults with vitamin D deficiency, the proportion of subjects with serum 25(OH)D concentrations ≥30 ng/mL within 12 weeks was 46.4% in the vitamin D(3) group and 3.6% in the placebo group (p < 0.0001). The proportion of subjects with serum 25(OH)D concentrations ≥30 ng/mL within 24 weeks was 73.2% in the vitamin D(3) group and 3.6% in the placebo group (p < 0.0001). Mean change in serum 25(OH)D concentrations at weeks 12 and 24 after vitamin D(3) injection was 12.8 ± 8.1 and 21.5 ± 8.1 ng/mL, respectively, in the vitamin D(3) group, with no significant changes in the placebo group. Serum parathyroid hormone concentrations showed a significant decrease in the vitamin D(3) group but no change in the placebo group. CONCLUSION: Intramuscular injection of vitamin D(3) 200,000 IU was superior to placebo in terms of its impact on serum 25(OH)D concentrations, and is considered to be safe and effective in Korean adults with vitamin D deficiency.