Obesity linked to poorer asthma treatment response

NEW YORK (Reuters Health) - Lab experiments indicate that people with asthma who are overweight or obese have a reduced response to steroid treatment, compared with their lean counterparts.

Inhaled steroids are the mainstay of asthma treatment, because they reduce airway inflammation that can lead to an asthma attack.

"This study identifies what could be a significant issue for the 20 million Americans with asthma; specifically, the main controller medication might be less effective if you are overweight or obese," lead author Dr. E. Rand Sutherland, from National Jewish Medical and Research Center in Denver, said in a statement.

The study involved 45 non-smoking adults, including 33 with asthma and 12 without. It looked at the response of the participants' blood cells and lung cells to a steroid, dexamethasone, by measuring the production of an enzyme called MKP-1.

Steroid-induced expression of MKP-1 in both cell types was significantly lower in overweight/obese asthmatics than in lean asthmatics. For example, MKP-1 production by blood cells increased 5.27-fold in the lean group but only 3.11-fold in the overweight group, the researchers report in the American Journal of Respiratory and Critical Care Medicine.

By contrast, weight did not influence the MKP-1 response in subjects without asthma.

Further research, the authors conclude, is needed to clarify the mechanisms by which an elevated body mass index blunts the response to steroids in people with asthma.

SOURCE: American Journal of Respiratory and Critical Care Medicine, October 2008.