In a novel study of 717 children between ages 6 and 17, researchers have identified major factors associated with asthma severity in children from inner-city communities. They found that poor lung function, sensitivity to certain inhaled allergens, and exposure to second-hand smoke were important factors affecting asthma severity. The National Institute of Allergy and Infectious Diseases (NIAID) funded the work with additional support from the National Center for Advancing Translational Sciences, both parts of the National Institutes of Health (NIH).
The researchers gathered information on the children’s symptoms and response to guidelines-based asthma therapy, their environment, and other known risk factors bimonthly for one year. They observed that difficult-to-control cases of asthma were marked by persistently poor lung function and symptom exacerbations in the spring and fall, despite the use of high-dose medications. Difficult-to-control asthma was identified based on asthma control surveys and physical assessments.
By modeling the collected data, researchers examined how a variety of factors contribute to the severity of a child’s asthma. Sensitivity to a large number of inhaled allergens was linked to the presence of allergy-driven inflammation, which, in turn, is associated with poor lung function that results in severe asthma. Researchers also found that inflammation in the nasal passages, known as rhinitis (a common symptom of colds and hay fever) and second-hand smoke were both associated strongly with asthma severity. The researchers’ model will help clarify how various risk factors directly and indirectly affect asthma severity and may help prioritize efforts to manage difficult cases.
Based on computer analyses, the researchers identified five clusters of children distinguished by their asthma characteristics. Notably, one cluster experienced few allergy problems and, therefore, the investigators say, requires further study to understand the cause of their severe asthma. The researchers plan to continue working with this inner-city population to investigate appropriate interventions tailored to specific groups of children.
The Inner City Asthma Consortium (ICAC), a nationwide clinical network supported by NIAID, conducted the research in nine U.S. cities. Study participants were provided high-quality asthma and rhinitis care. The findings appear in three new reports published in the Journal of Allergy and Clinical Immunology.
Pongracic JA et al. Distinguishing Characteristics of Difficult-to-Control Asthma in Inner-City Children and Adolescents. Journal of Allergy and Clinical Immunology DOI: 10.1016/j.jaci.2016.06.059 (2016).
Liu AH et al. Pathways through which Asthma Risk Factors Contribute to Asthma Severity in Inner-City Children. Journal of Allergy and Clinical Immunology DOI: 10.1016/j.jaci.2016.06.060 (2016).
Zoratti EM et al. Asthma Phenotypes in Inner-City Children. Journal of Allergy and Clinical Immunology DOI: 10.1016/j.jaci.2016.06.061 (2016).
Peter Gergen, M.D., medical officer within the Allergy, Asthma and Airway Biology Branch in NIAID’s Division of Allergy, Immunology and Transplantation is available for comment.