Obesity might be to blame for about a quarter (23% to 27%) of asthma in children who are obese.
This is according to researchers at Duke University and collaborators with the National Pediatric Learning Health System (PEDSnet), published by the journal Pediatrics.
Jason E. Lang, M.D., associate professor of pediatrics at Duke, is the study’s lead author. Other authors include H. Timothy Bunnell, Jobayer Hossain, Tim Wysocki, John J. Lima, Terri H. Finkel, Leonard Bacharier, Amanda Dempsey, Lisa Sarzynski, Matthew Test and Christopher B. Forrest.
For the study, researchers analyzed data for 507,496 children from more than 19 million doctor’s visits at six major children’s health centers. The data were entered into a clinical research data network called PEDSnet between 2009 and 2015.
Those classified as having asthma had been diagnosed at two or more doctor’s appointments and had also received a prescription, such as an inhaler. Tests of their lung function also confirmed they had the disease.
Children classified as obese – those with a body-mass index (BMI) in the 95th percentile or above for their age and sex – had a 30% increased risk of developing asthma than peers of a healthy weight. Asthma did not affect just those with obesity. Children who were overweight but not obese (BMI in the 85-94th percentile) also had a 17% increased asthma risk compared to healthy-weight peers.
The researchers calculated asthma risk using several models and adjusted for risk factors such as sex, age, socioeconomic status and allergies. The results remained similar.
“Asthma is the No. 1 chronic disease in children and some of the causes such as genetics and viral infections during childhood are things we can’t prevent,” said Lang. “Obesity may be the only risk factor for childhood asthma that could be preventable. This is another piece of evidence that keeping kids active and at a healthy weight is important.”
The study has limitations, Lang admitted, including that the data were collected during doctor’s visits and not in a controlled clinical research setting. Lang said more experiments are needed to prove overweight and obesity directly cause changes that lead to asthma because scientists don’t completely understand how or why this would occur.