The researchers enrolled 86 children in the study, including 36 children with STRA, 26 with moderate asthma and 24 non-asthmatic controls, and measured the relationships between vitamin D levels and lung function, medication usage and symptom exacerbations.The researchers also examined tissue samples from the airways of the STRA group to evaluate structural changes in the airway's smooth muscle.
At the conclusion of the study the researchers found children with STRA had significantly lower levels of vitamin D, as well as greater numbers of exacerbations, increased use of asthma medications and poorer lung function compared to children with moderate asthma and non-asthmatic children. Airway muscle tissue mass was also increased in the STRA group.
"The results of this study suggest that lower levels of vitamin D in children with STRA contribute to an increase in airway smooth muscle mass, which could make breathing more difficult and cause a worsening of asthma symptoms," Dr. Gupta said.
The findings suggest new treatment strategies for children suffering from difficult-to-treat asthma, he added.
"Our results suggest that detecting vitamin D deficiency in children with STRA, and then treating that deficiency, may help prevent or reduce the structural changes that occur in the airway smooth muscle, which in turn may help reduce asthma-related symptoms and improve overall lung function," Dr. Gupta said.
Before any widespread treatment recommendations can be made, however, larger studies will
"The determination of the exact mechanism between low vitamin D and airway changes that occur in STRA will require intervention studies," Dr. Gupta said. "H
|Contact: Brian Kell|
American Thoracic Society