Link Between Obesity and Asthma Discovered

Obesity may cause asthma by altering the immune system, study says.

There are studies that have looked into the links between asthma and obesity, but until now, the reason for the link has been unknown. Boston Children’s Hospital officials say that both conditions have become more common over the last several decades. A new study led by Dr. Dale Umetsu and Hye Young Kim of the Division of Allergy and Immunology at Boston Children’s, explored obesity’s effects on the immune system.

“Since it’s been a puzzle to understand why obesity predisposes people to asthma, our goal was to find the connection between these two problems, which occur in both children and adults and to explore possible new treatments,” Umetsu says in a press release.

The research conducted at Boston Children’s Hospital indicates that obesity might cause asthma due to factors in the immune system, and the study suggests a new way of treating asthma in obese people. Boston Children’s says that obese people often respond poorly to standard asthma medications.

The study, conducted in a mouse model of asthma and in human lung fluid, was published online December 15th in the journal Nature Medicine. The researchers studied mice that were fed a high-fat diet causing them to become obese. Unlike mice fed normal diets, the obese mice developed airway hyper-reactivity or constricted and twitchy airways, the predominant feature of asthma.

In the study, obesity appeared to alter the immune system—the body’s first responder to infection—in several ways to cause lung inflammation. “We have discovered an inflammatory pathway to asthma that previously had not been recognized,” Umetsu says. “This pathway may be resistant to standard asthma medications such as corticosteroids.”

Note: After the study concluded, Umetsu accepted the position of principal medical director at Genentech. He is no longer affiliated with Boston Children’s Hospital.