ST. LOUIS, MO. – A new study following nearly 800 asthmatic patients over 15 years shows the progression toward worse lung function in those who become obese as they age.
None of the participants of the Washington University School of Medicine study were obese at the beginning of the research project (ages 5-12), yet 25 percent were obese by the end of the study (early twenties).
Researchers reported that pediatric asthma patients who had become obese by their early twenties had measurably worse lung function than those with asthma who didn’t become obese by the end of the study.
Surprisingly, both groups showed no difference in the severity of their asthma symptoms.
“In extreme situations in adults (morbid obesity), the chest wall is so thick that it interferes with movement and there are decreases in lung function on that basis,” explained Robert C. Strunk, MD, a pediatrics professor at Washington University, who treats patients at St. Louis Children’s Hospital in St. Louis, Mo. “This is a different kind of abnormality (a restriction because of the interference with movement) than we found, which was obstruction due to the airways being more narrow and nothing to do with the chest wall. Others have shown in adults with asthma and obesity (and the same obstruction we found) that there’s likely to be some connection between the airways being narrow and molecules that come from fat tissue and cause inflammation. We didn’t collect data to examine this possibility in our study population, but the obstruction in those who became obese is likely to be related to some type of increased inflammation related to the fat tissue.”
Study findings differ from research in older obese patients with asthma, who have more difficulty controlling their symptoms and as a result, need more medications.
“Our study suggests that younger obese patients can expect worsening lung function as they age,” said Strunk. “We want to emphasize that doctors and patients need to pay attention to weight.”
Strunk noted it’s encouraging that obese young adults in the study don’t report worse asthma symptoms.
“But it’s worrisome that their lung function has clearly gotten worse,” he quickly added.
The CAMP (Childhood Asthma Management Program) research group has published more than 150 articles on the study results, with many publications focusing on the genetics of asthma and/or clinical outcomes.
“We’re now working on determining characteristics of the children when they were school age that were associated with the onset of smoking cigarettes,” he said. “In spite of our best efforts and their asthma, yes, some 20 to 25 percent were smokers.”
Strunk noticed no difference in outcomes by gender. “Young men and women gained weight and had decreased lung function,” he said.
When asked about indications whether asthma symptoms had any effect on gaining weight, Strunk said many thought participants with more asthma symptoms might exercise less and therefore gain more weight. “Or that those who gained weight were the sickest and took more steroid medication,” he said. “Neither symptoms nor steroids were related to the changes in lung function … and thus on gaining weight.”
Trial patients were enrolled in CAMP, a nationwide study originally designed to determine best practices in treating asthmatic pediatric patients. In 2000, the study produced a landmark paper in The New England Journal of Medicine that altered the standard of care for children with asthma when it demonstrated that a regular medication routine was superior to as-needed asthma treatments.
“That paper launched a whole new approach to childhood asthma management, changing the guidelines for physicians treating those patients,” Strunk pointed out. “We were fortunate to be able to continue following this group of children all the way to their mid-twenties. Nobody had been able to do that before. We could answer a lot of questions with data gathered over such a long period of time.”
Because CAMP study patients were only their twenties, they weren’t old enough to have developed COPD. “Good studies show that childhood asthma is a clear risk factor the development of COPD,” he said.
Research from the Washington University study was published in a 2015 edition of The Journal of Allergy and Clinical Immunology.
LINKS:
Dr. Robert Strunk, Washington University School of Medicine: https://wuphysicians.wustl.edu/for-patients/find-a-physician/robert-c-strunk
The Journal of Allergy and Clinical Immunology: http://www.jacionline.org/
The New England Journal of Medicine: http://www.nejm.org/
Washington University School of Medicine: http://medicine.wustl.edu/