Obesity is a risk factor for asthma, and new research shows the excess of fatty tissue in obese persons also helps clog up the lungs.

The study published in the European Respiratory Journal found that fatty tissue can accumulate in the airway walls of obese people, possibly contributing to asthma and other respiratory problems. It finally explained how this link might be problematic for overweight or obese people because it may contribute to the development of respiratory conditions.

"Our research team studies the structure of the airways within our lungs and how these are altered in people with respiratory disease," John Elliot, study first author from Sir Charles Gairdner Hospital in Perth, Australia, said.

"Looking at samples of lung, we spotted fatty tissue that had built up in the airway walls. We wanted to see if this accumulation was correlated with body weight."

To answer this question, researchers analyzed lung samples collected post-mortem from 52 lungs people had donated for research. Of this number, 15 had not had asthma, 21 had had asthma but died due to unrelated causes, and a further 16 died due to asthma-related causes.

Researchers used special dyes to study the structure of 1,373 airways to identify how much fatty tissue was present in them. They also looked at each donor's BMI, or body mass index.

What the team found is that fatty tissue really does accumulate in airway walls. They also found the higher a person's BMI, the more fat accumulates in the airways.

More alarmingly, they confirmed the fat buildup might affect the normal structure of the airways by blocking them, and causing inflammation in the lungs. This outcome might contribute to asthma and other respiratory problems.

"Being overweight or obese has already been linked to having asthma or having worse asthma symptoms," according to Dr. Peter Noble, Ph.D., study co-author.

asthma inhaler
The number of people with asthma continues to grow every year, the CDC reports. Photo courtesy of Pixabay

"Researchers have suggested that the link might be explained by the direct pressure of excess weight on the lungs or by a general increase in inflammation created by excess weight. This study suggests that another mechanism is also at play."

Dr. Noble said they've found that excess fat accumulates in the airway walls where it takes up space and seems to increase inflammation within the lungs. The team believes this causes a thickening of the airways that limits the flow of air in and out of the lungs. This will at least partly explain an increase in asthma symptoms.