A new study has found that obese people are significantly more likely to have persistent or severe persistent asthma than their slimmer counterparts.
The study was conducted by a team of researchers led by Brian Taylor at Emory Crawford Long Hospital in Atlanta.
As part of the study, researchers took data from the National Asthma Survey, which includes 5,741 asthmatics and looked at 3,059 adults with asthma, who were divided into three groups: non-overweight, overweight and obese, based on their body mass index (BMI).
Researchers found that compared to non-overweight asthma patients, obese patients (BMI=30) were more likely to report having continuous symptoms, had more ER visits, missed more days of work, used more rescue inhaler medications and used inhaled steroids to control asthma.
"There have been a number of studies on obesity and asthma prevalence, but until now there has been little data on obesity and asthma severity," Taylor said.
"We had enough data to adjust for other factors, such as gender, race, income and employment status, and ensure that these factors were not playing a role in the results. Even after taking these variables into account, the association between obesity and asthma severity still held," he added.
Like many previous studies, this research also shows the link between asthma and obesity is more prominent in women.
"A big part of that is simply that 70% of the study subjects were women. We did find a statistically significant association between obesity and asthma severity in men, too," he said.
Researchers conclude that while it's not known for sure how asthma and obesity are linked, one potential mechanism seems to be an association between the hormone leptin, which is produced by fat cells and plays a role in body weight regulation, and inflammation of airways seen in asthma. Obesity also may impact the lungs in other ways to increase the risk of asthma.
The findings of the study were presented at the American Thoracic Society 2007 International Conference.