The surgical removal of tonsils and adenoids in children with sleep apnea may mitigate asthma, reveals a new study published in PLOS Medicine.

"Several small studies have described a strong association between obstructive sleep apnea and asthma: two common inflammatory conditions that impair breathing in children,” lead author Rakesh Bhattacharjee, assistant professor of pediatrics at the University of Chicago, said in a news release. “But we wanted to test the strength of the connection when studied in a much larger population.”

Researchers from the University of Chicago analyzed data from more than 40,000 children between the ages of 3 and 17. About 13,500 of those children who had asthma had their adenoids and tonsils removed to improve obstructive sleep apnea. Researchers compared their asthma symptoms from the year before surgery to the year after.

The data showed that one year after the operation, children who underwent the procedure saw a 30 percent reduction in acute asthma exacerbations and a 38 percent decrease in acute status asthmaticus— a condition that doesn’t respond to traditional treatments such as inhalers or steroids.

They compared the data to that of more than 27,000 children who had asthma but still had their tonsils and adenoids, which constituted the second part of the 40,000 study group. The comparison group was carefully matched to the first group for age, sex and location, researchers noted.

Authors also observed that surgery patients had a 37 percent reduction in asthma-related hospitalizations and a 26 percent decline in asthma-related emergency room visits. Participants who did not undergo the operation did not have apparent reductions.

Asthma is the third-most common chronic disease among U.S. children and third-most common cause of hospitalization of American children under age 15, according to the news release. The Centers for Disease Control and Prevention (CDC) estimates that it impacts 7.1 million children.

The condition is also one of the most costly respiratory diseases in the U.S.— the direct health care costs of childhood asthma exceeded $50 billion a year, according to previous research.

While researchers of the new study found the link between the surgery among children with sleep apnea who had less severe asthma symptoms, they noted that a prospective, randomized and controlled clinical trial is still needed to indicate a direct, causal relationship.

They also noted that they drew the study participants from a database that only included children with insurance— not those with government coverage or without health insurance.

Despite those limitations, the study authors said their findings may hold promise for the development of future asthma treatments.

"Our study adds weight to the growing sense that obstructive sleep apnea aggravates asthma and further tips the balance toward early identification of obstructive sleep apnea," Bhattacharjee said. "This will help physicians advocate for surgical intervention, not just to eradicate sleep-disordered breathing, but also to reduce asthma severity and decrease reliance on medications in asthmatic children."