WEDNESDAY, May 23, 2007 (HealthDay News) -- Severe, persistent asthma is more likely to strike obese individuals than people who are not overweight, U.S. researchers report.
In their study, a team at Emory Crawford Long Hospital in Atlanta examined data from the U.S. National Asthma Survey.
"Our analysis showed that out of more than 3,000 patients with asthma, obese patients were 66 percent more likely to report continuous symptoms, 36 percent more likely to miss more days of work and 52 percent more likely to be classified as having either moderate or severe persistent asthma when compared to non-overweight people," Dr. Brian Taylor, a pulmonary fellow, said in a prepared statement.
These findings held true after the researchers adjusted for factors including gender, race, age, smoking status, and family history of asthma.
Taylor said he and his colleagues, "noted that obese patients were more likely to have less education, be unemployed and be African-American."
They also found that obese people with asthma made more frequent emergency room visits and used daily controller and as-needed rescue medications more often. The association between obesity and asthma severity seemed slightly stronger in women than in men, which has been noted in previous studies.
The study was to be presented Wednesday at the American Thoracic Society's international conference in San Francisco.
The exact link between obesity and asthma severity is not clear, but it may be that severe asthma leads to reduced physical activity, which results in weight gain. The researchers also suggested that the hormone leptin may be a factor.
Leptin is produced by fat cells and plays a role in weight regulation. Previous research has suggested that leptin may also contribute to airway inflammation in asthma patients.
The U.S. National Heart, Lung, and Blood Institute has more about asthma.