A new study shows that aspirin appears to reduce the chances of developing asthma. At least that is what happened in a randomized study of 22,071 healthy male physicians. Some took a low dose of aspirin every other day while others took a placebo. Neither group knew which they were taking, but the people in the group that got aspirin were less likely to develop asthma during the course of the study.

The findings of the double-blind Physicians' Health Study appear in the January 2007 issue of the "American Journal of Respiratory and Critical Care Medicine."

More than 20 million Americans were estimated to have asthma in 2004. The chronic inflammatory disease causes obstructive lung problems. Breathing difficulties from asthma usually occur during "attacks." At that time the airways narrow, the lining swells, respiratory muscles tighten and mucus secretions increase, making breathing difficult.

Tobias Kurth, M.D., Sc.D., of the Division of Aging at Brigham and Women's Hospital in Massachusetts, and five associates studied physicians ages 40 to 84 over a period of 4.9 years.

"Aspirin reduced the risk by 22 percent of newly diagnosed adult-onset asthma," Kurth said in the statement. "These results suggest that aspirin may reduce the development of asthma in adults. They do not imply that aspirin improves symptoms in patients with asthma."