As Pounds Go Up, So Does Risk of Asthma
Precise role weight plays in the disease remains unclear

(HealthDay News) -- People who are overweight or obese are 50 percent more likely than their normal-weight peers to develop asthma, research has shown, prompting a call for public health efforts aimed at controlling asthma to highlight the need for weight management.

The finding came from an analysis of data from seven studies that looked at asthma and body mass index (BMI) in more than 333,000 people with severe asthma. The studies were conducted between 1966 and 2006 in Canada , Europe and the United States .

The review found that the risk of asthma increased by at least 50 percent among people who were overweight (a BMI of 25 to 29) or obese (BMI greater than 30). The heavier the person, the greater their risk of asthma -- a finding that proved true in both men and women. The results were published in the American Journal of Respiratory and Critical Care Medicine .

"The bottom line is that being overweight appears to significantly increase the risk of asthma," Dr. E. Rand Sutherland, of the National Jewish Medical and Research Center in Denver , told HealthDay . "But the caveat is that until further studies are done, it won't be clear exactly what type or severity of asthma is present in obese people."

More than two-thirds of American adults are believed to be overweight or obese, which means that millions more adults in the United States may be at risk of developing asthma than was previously thought. Sutherland and a study colleague suggested that "significant weight loss" could potentially reduce asthma cases by as many as 250,000 a year.

They also said asthma should join diabetes, sleep apnea, stroke, arthritis and cardiovascular diseases on the list of health problems for which excess weight is a risk factor.

The finding that weight might increase asthma risk in both men and women was most interesting, said Dr. Norman H. Edelman, chief medical officer for the American Lung Association and a professor of preventive medicine at Stony Brook University in New York .

"There's a lot of work that suggested the [obesity] effect was there in women and not in men," Edelman told HealthDay . "Certainly, in terms of my own clinical practice, I see people -- men and women -- with asthma that's difficult to manage, and many of them are overweight. But for men, it's something that wasn't clear before, and that's why this analysis is valuable."

However, it' still not clear whether being overweight or obese actually causes asthma.

"The problem with asthma is that, unlike many other diseases, it's not like flipping a switch. It's not that you have it or don't have it. There are a lot of people walking around with a little bit of asthma, and they don't even know it," Edelman said. "So it's not clear if obesity is actually causing the disease or perhaps converting a pre-existing undiagnosed asthma into a severe asthma. So, I don't know if I would say that obesity causes asthma. But certainly, it's a risk factor for clinically significant asthma."

On the Web

To learn more about asthma, visit the American Academy of Allergy, Asthma & Immunology.

SOURCES: HealthDay News ; E. Rand Sutherland, M.D., National Jewish Medical and Research Center, and assistant professor of medicine, University of Colorado, Denver; Norman H. Edelman, M.D., chief medical officer, American Lung Association, and professor of preventive medicine, Stony Brook University, Stony Brook, N.Y.; April 2007, American Journal of Respiratory and Critical Care Medicine
Author: Robert Preidt
Publication Date: April 30, 2008
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