Vitamin D Supplementation Does Little to Improve Asthma Control

In patients with asthma, lower serum levels of 25-hydroxyvitamin D have been associated with more-frequent exacerbations, airway hyper-responsiveness, and decreased lung function. Low vitamin D levels theoretically could exacerbate pro-inflammatory states and reduce corticosteroid responsiveness. To determine whether vitamin D supplementation improves responsiveness to corticosteroid therapy, investigators randomized 408 adults (mean age, 40) with asthma and 25-hydroxyvitamin D levels <30 ng/mL (mean, 18.8 ng/mL) to high-dose oral vitamin D₃ supplementation (initial dose of 100,000 IU followed by 4000 IU daily) or placebo for 28 weeks. All participants received the inhaled corticosteroid ciclesonide (320 μg daily). During the study period, …