Obesity is Associated with Airway Dysanapsis in Kids With or Without Asthma

FORNO_ERICK_MD_PDP_20120821_One of my main research interests is on childhood asthma, and in particular why and how obesity can make childhood asthma more severe. A few years ago we reported that obese children with asthma do not respond well to inhaled steroids, the main controller medication for asthma.

In a recent study published in the American Journal of Respiratory and Critical Care Medicine, we evaluated one potential reason: whether obese children have anatomical or developmental changes in their airways, which are relatively more narrow when compared to their larger lungs. This may explain why they have more symptoms, and why they don’t respond less to asthma medications.

We analyzed information from over 4,500 children from six different studies (one in Pittsburgh, one in Boston, one in Puerto Rico, one across the United States, one clinical trial in the United States and Canada, and one study from the Netherlands) to determine if being overweight or obese is associated with “airway dysanapsis” in children and adolescents.

Dysanapsis means that, while the lungs are of normal size or even larger than in other children, the airways are too narrow compared to the lungs. We found that overweight and obese children had 2 to 4 times higher risk of dysanapsis; in other words, that their lungs tend to be larger than in other children, but their airways tend to be smaller. This can make it more difficult to breathe, even in obese children without asthma. In children with asthma who are overweight or obese, dysanapsis led to more symptoms of asthma, more need for medications, 2 to 3 times more asthma flare-ups, more hospitalizations, and more frequent need for steroids.

Our results show that being overweight or obese may lead to changes in the size of the airways, which may be too narrow for the size of the lungs. This can be associated with worse lung function. In children with asthma who are obese, these changes can lead to more symptoms, more flare-ups, and lower response to asthma medications. Studies like these improve our understanding of “obese asthma”; our hope is that this will help us better treat these patients and improve their quality of life.

Obesity in children can worsen lung function, place children at higher risk of asthma, and make their asthma more severe. This is yet another reason to maintain a healthy weight and lifestyle.

For more information, please visit www.chp.edu/our-services/pulmonology/services/asthma.