Allergy may foretell breathing trouble.

The dust that makes you sneeze today may give you breathing problems in the future, says a new report.

Daniel J. Gottlieb and George T. O'Connor of the Boston University School of Medicine knew that smoking can lead to chronic obstructive pulmonary disease (COPD), a permanent narrowing of the lung's airways. So they examined people who react to common allergens to see whether they also risk acquiring this disorder.

Gottlieb, O'Connor, and their colleagues analyzed data collected from 1,025 male veterans who had been participating in a study of aging. The researchers tested the men for allergies to house dust, ragweed, and pollen from trees or grasses. They also measured the veterans' lung function periodically. While everyone loses some lung function with age, the team found that the men with allergies lost more than the average older person's 30 milliliters per year. Lung function, measured by the volume of air a person can expel in a second, fell by an additional 9.45 milliliters among these veterans, the investigators report in the February American Journal of Respiratory and Critical Care Medicine. The correlation persisted even after the researchers factored out smoking, which results in a loss of about 28 milliliters. This finding suggests that allergies may prove to be an independent risk factor for chronic obstructive pulmonary disease.

Will that small drop in lung function make a difference? Over 20 or 30 years, even small losses start to add up, O'Connor says.

The researchers speculate that allergies cause inflammation, which, in turn, may cause permanent damage and narrowing of the airway.