THURSDAY, June 4, 2009 (HealthDay News) -- New research suggests that obesity may not worsen asthma, as many experts have thought, but it could dampen the response to medications commonly used to manage the chronic condition.
Inhaled corticosteroids are the most widely prescribed drugs to treat a burgeoning number of people with asthma, many of whom are overweight or obese.
"It raises the concern that obese people with asthma may not respond as well to guideline-based treatments," said Dr. E. Rand Sutherland, lead author of a study published in a recent issue of the Journal of Allergy and Clinical Immunology and an associate professor of medicine at National Jewish Health and the University of Colorado, in Denver. "If doctors don't reassess obese patients after they've started treatment with inhaled steroids, ask if they're working effectively or don't make appropriate modifications, then obese people with asthma could be less effectively treated than their counterparts."
Another expert agreed with the assessment.
"This may mean we need to give these patients more medication," said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City. "If they respond less well, then we may have to dose more by body weight, and now most asthma medications are standardly dosed."
Asthma is becoming more prevalent, and previous research has hinted that there may be a link between being overweight or obese and asthma.
"There has been a suggestion that obesity and asthma may be related, particularly with regard to obesity increasing one's risk of developing asthma or making asthma more severe or difficult to treat," Sutherland said.
One study from last year reported that obese people who have asthma are nearly five times more likely to be hospitalized for the problem and to have a lower quality of life and worse control of the disease than those with asthma who are normal weight.
But more recently, studies have been coming in suggesting that this may not be not the case, Sutherland said.
For this latest study, Sutherland and colleagues looked at body mass index (BMI) and treatment data on 1,256 individuals with mild-to-moderate asthma.
Overweight and obese participants fared slightly worse on standard measures of asthma severity, such as lung function and predisposition to airway constriction, Sutherland said, but not enough to result in any real clinical difference.
"Having a high BMI doesn't really appear to be associated with more severe forms of asthma," he added.
Horovitz did point out that heavier people tend to have more shortness of breath. "We might have assumed it was worse asthma," he said.
Response to medications, however, took a different tilt.
When analyzing a subgroup of 183 people, lean people using inhaled corticosteroids showed a 55 percent lower level of one measure of airway inflammation.
The exact reasons for these findings are unclear, indicating the need for more studies, the researchers said.
More information
The National Heart, Lung, and Blood Institute has more on asthma.
