How does obesity increase the risk of developing asthma in adulthood?

A summary of research published in ERJ Open Research

Asthma is a complex disease that affects people in different ways. Obesity, when a person has a BMI of over 30 kg/m2 combined with large stores of body fat rather than muscle, can increase the risk of developing a type of asthma that is not seen in other groups of people. This study looked at what happens in the body when people who are obese develop asthma, to try and understand the increased risk.

What did the study look at?

The researchers compared the lungs of four groups of people: people in a healthy weight range without asthma, people in a healthy weight range with asthma, people who are obese without asthma and people who are obese with asthma. This was a small study and each group contained 10 or 11 people.

Researchers took measurements using different tests to look at how much air the lungs could hold and how well the lungs were working. Using these measurements and making comparisons between the different groups, the researchers built up a picture of how the lungs were affected by obesity and by asthma. 

What do the results show?

The results found that people who are obese with asthma had differences  in their breathing system compared to the other groups.

The main differences found were:

  • The total amount of air they could breathe out of their lungs during the tests was much lower than the other groups
  • The volume of air that was left in the lungs after breathing out was much lower than the other groups

The people with asthma who were obese struggled to open their lungs fully when they took a deep breath. They were also more likely to experience lung compression. This is when the airways in the lungs collapse or do not expand properly.

Why is this important?

These results suggest that there are abnormalities in the way the lungs work for people who are obese with asthma. Additionally, these abnormalities were different to people who were obese without asthma and to people in a healthy weight range with asthma. The findings could help us understand more about this type of asthma help us to find treatments that are tailored to this group of people.

Read the original research paper

Title: Physiological signature of late-onset nonallergic asthma of obesity