Vitamin D Oral Replacement in Asthma (VDORA1)

The overall objective of the study was to determine the pharmacokinetics of Vitamin D supplementation in children who have asthma and are overweight or obese. This study had two parts. In part 1, study participants were randomized to receive one of four doses of vitamin D supplementation in international units (IU) over at 16-week period: 1) Single 50,000 IU loading dose + 6000 IU daily dose; 2) Single 50,000 IU loading dose + 10,000 IU daily dose: 3) 6000 IU daily dose; or 4) 600 IU daily dose. Based on pharmacokinetic analysis, one of the doses (1-3) was selected to use in part 2. In part 2, study participants were randomized to the dose selected in part 1 or the 600 IU daily dose of vitamin D supplementation which were administered over a 16-week dosing period. Across both parts, safety of each dose regimen of vitamin D supplementation was evaluated, and the effectiveness of each dose to achieve a serum level of 25(OH)D greater than or equal to 40 ng/ml was assessed.