Researchers at Duke plan to answer this by conducting a study — Vitamin D Add-On Therapy Enhances Corticosteroid Responsiveness in Asthma (VIDA) — to see if patients who are given a vitamin D supplement see improved corticosteroid response and, consequently, achieve better asthma control.
Inhaled corticosteroids are currently the most effective treatment for targeting persistent asthma in children and adults. However, despite the success of this therapy, many patients do not respond to the corticosteroids, even when the medication dosage is increased.
Resistance to corticosteroids has been related to altered corticosteroid cellular sensitivity which could be the result of a reduced number of corticosteroid receptors, reduced corticosteroid receptor binding, increased corticosteroid receptor expression, and increased nuclear transcription factors.
Recent immunologic studies have shown that low vitamin D levels are related to high levels of inflammation and asthma.
“This leads us to believe that, by supplementing vitamin D levels in asthma sufferers, we can help them control their asthma symptoms more effectively,” says Monica Kraft, MD, principal investigator of the study and director of the Duke Asthma, Allergy, and Airway Center.
The 28-week study will enroll adults (18 years or older) who have vitamin D deficiency and asthma with persistent symptoms despite taking a low-dose inhaled corticosteroid (ICS).
Participants on low-dose inhaled corticosteroid will be randomly assigned to one of two groups. One group will receive an add-on therapy with a placebo and the other will receive a high-dose of vitamin D (100,000 IU load followed by 4,000 IU/day).
Kraft notes that study results could have important implications for clinicians who treat asthma. “Given the high prevalence of both vitamin D insufficiency and asthma, this trial has high potential to impact daily asthma management. If we show a conclusive link between vitamin D deficiency and loss of asthma control, then we can make firm recommendations about how to replace vitamin D effectively for asthma sufferers.”
This study is being conducted by AsthmaNet, a clinical research network established by the National Heart Lung and Blood Institute to develop and conduct clinical trials that explore new approaches to treating asthma.
Duke is one of nine adult centers in the U.S. who is part of this network.