Abnormal lung function in obese asthmatic children increases the risk of uncontrolled asthma

Published: September 28, 2021

Obesity in children is a risk factor for developing asthma. Furthermore, obesity in those with asthma is associated with poor asthma control, decreased responsiveness to asthma controller medication, and increased emergency department visits and hospitalizations. The mechanism whereby obesity affects more severe asthma is not completely understood. Previous studies have shown that children with asthma have large airways with obstruction of the conducting airways, a pattern called dysanapsis, as well as obstruction of the small or peripheral airways, referred to as peripheral airway impairment or PAI. Both dysanapsis and PAI have been associated with poor asthma outcomes. The purpose of this study was to further establish whether the poor asthma outcomes associated with obesity in children were related to these lung function abnormalities.    

As described in The Journal of Allergy and Clinical Immunology in Practice, Galant et.al. evaluated 206 children with asthma, ages 4 to 18 years with moderate to severe asthma, for their weight category ranging from normal weight to obese, determined by their body mass index (BMI) percentile. Also determined was the presence of uncontrolled asthma, defined by NIH asthma guidelines. Lung function was measured by spirometry and impulse oscillometry, the latter well suited to detect PAI.

Children with asthma who were overweight and obese had evidence of significantly increased dysanapsis and PAI. The relationship of obesity to uncontrolled asthma appeared to be based on the presence of dysanapsis and PAI. In fact, without these abnormal lung functions, the authors found that obesity alone was not significantly related to uncontrolled asthma.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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