Approximately 250,000 people per year in the U.S. develop asthma because of weight gain. Asthma is often thought of as a disease of children, who have difficulty breathing when their airways constrict in response to infections, exercise and allergies – and that is one type of asthma. However, we live in a time when many people (all over the world) are struggling with their weight. Gaining weight is now a major risk factor for the development of asthma, and the majority of people with severe asthma in the United States also suffer with obesity.
This would be alarming enough, but work we’ve done here at the University of Vermont has shown that people who are overweight tend to suffer with more severe asthma, and do not respond as well to the usual asthma treatments as people who are lean, and may even get worse on some of the treatments that work well in lean people. Perhaps this is not surprising, as asthma medications were not developed to treat asthma in people who are overweight, and airway narrowing in people who are overweight may differ from airway narrowing in response to allergies and infections in people who are lean.
We’ve been working very hard at the University of Vermont to try and understand what causes asthma in people who gain weight, so that we can find better treatments for them. One of the first questions we asked, was what happens to asthma if you lose weight? We followed a number of people with asthma as they went through the weight loss surgery program here. We found they had dramatic improvements in their asthma symptoms, but the tendency of their airways to be reactive, or twitchy, differed depending on whether they had childhood onset allergic asthma, or had developed asthma without allergies later in life. Those who had childhood onset allergic asthma had fewer symptoms after surgery, but their airways still tended to be twitchy and narrow more easily than normal. The group of people who tended to be older without allergies when they developed asthma not only felt much better, but the tendency of their airways to be twitchy got much better.
This helped us to refocus our efforts to find treatments and understand the causes of asthma in people who gain weight: we realized there were different types of asthma in people that were overweight – some had childhood onset asthma that was complicated and worsened by weight gain, and others developed asthma only because of the weight gain.
We now have a multidisciplinary team of doctors in radiology, surgery and pulmonary medicine, working with bioengineers in the College of Medicine trying to understand what happens to the airways of people who develop asthma when they gain weight – not everybody does. Those who do develop asthma with weight gain seem to have outer airways that collapse more easily. Collapsed airways make it more difficult to breathe. By understanding why this happens, we hope to develop customized treatments that might be effective to treat this form of asthma.
The obesity epidemic has had a major impact on people suffering with asthma. At the University of Vermont a number of scientists and doctors are working together to understand how weight gain and diet affect asthma. We are trying to find better ways to treat this form of asthma. This fall, we will host our 3rd Scientific Conference on “ Obesity and Metabolism: An Emerging Frontier in Lung Health and Disease” at UVM’s Davis Center, this will be attended by physician and scientists from around the world. We hope to accelerate and prioritize research in this area, with the ultimate goal of improving patient care for individuals suffering with obesity and lung disease.
Anne Dixon, MD, pulmonologist, is medical director of Pulmonary Disease and Critical Care Medicine at The University of Vermont Medical Center. She is also Professor at the Larner College of Medicine at UVM.