Vitamin D Deficiency Linked to Severe Asthma in Children
A vitamin D deficiency could be the reason why some children with asthma experience worse lung function and more severe symptoms. London researchers believe insufficient vitamin D levels may cause structural changes in the airway muscles of children who have severe therapy-resistant asthma (STRA), which impairs their breathing.
Vitamin D study could lead to new treatments
Childhood asthma is a major problem, affecting 10% of children, according to the Centers for Disease Control and Prevention (CDC). Among non-Hispanic black children, however, the rate is 17%, a segment of the population that has seen nearly a 50% increase in asthma from 2001 through 2009.
Standard treatment for childhood asthma is low doses of corticosteroids, which is effective in most cases, yet 5 to 10 percent of children are resistant to this approach. These children have severe therapy-resistant asthma, and as a result suffer more asthma attacks, need more healthcare services, and experience more asthma-related problems than do children with less severe asthma.
The researchers reached their conclusions about vitamin D after conducting a study of 86 children (mean age, 11.7 years), 36 of whom had STRA, 26 with moderate asthma, and 24 who were asthma-free. Vitamin D levels, lung function, use of medication, and symptoms were tabulated for all the participants, while airways tissue samples were collected from 22 of the 36 children with severe asthma.
Analysis of the data showed that children with STRA had significantly lower levels of vitamin D, a greater use of asthma medications, more exacerbations of symptoms, and worse lung function when compared with children in the other two groups. In addition, the tissue samples revealed an increase in airway smooth muscle.
According to Atul Gupta, MRCPCH, MD, a researcher from Royal Brompton Hospital and the National Heart and Lung Institute at Imperial College and King’s College London, their findings “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.”
The positive news to derive from the study is that “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,” noted Dr. Gupta.
Seventy percent of school-age children do not get enough vitamin D, according to a recent report in Pediatrics. In addition to placing children at risk for heart disease, weak bones, and high blood pressure, a vitamin D deficiency now appears to be detrimental for children with severe asthma.
Centers for Disease Control and Prevention, Vital Signs May 2011
Gupta A et al. Relationship between serum vitamin D, disease severity and airway remodeling in children with asthma. American Journal of Respiratory and Critical Care Medicine 2011; doi: 10.1164/rccm.201107-1239OC
Melamed ML et al. Prevalence and associations of 25-hydroxyvitamin D deficiency in children and adolescents in the United States: results from NHANES 2001-2004. Pediatrics 2009 Aug 3