The results of a new study appear to expand the link between traffic exposure and poor lung function among people with asthma.

In a study of 176 adults with asthma or rhinitis, Dr. John R. Balmes, of the University of California, San Francisco, and colleagues found “the closer adults with asthma live to roadways with heavy traffic…the lower their lung function.”

“Living close to any road was associated with lower lung function,” Balmes told Reuters Health.

Other studies have shown lung health effects from major roadways, Balmes and colleagues note in the Journal of Allergy and Clinical Immunology. “Ours is the first to show evidence that living near any road can do so,” said Balmes.

He and colleagues therefore advise asthma patients minimize their traffic exposures.

The researchers assessed lung function and quality of life measures among the 176 adults (71 percent female) who were about 43 years old, on average, and undergoing treatment for chronic asthma with rhinitis (145 individuals) or rhinitis alone (31 individuals). The groups had similar proportions of current and former smokers.

Balmes’ team found out how close each participant lived to the nearest roadway using road-location data provided by geographic information systems. They then compared lung function with the distance from a roadway of any type.

Those living the closest to a roadway had the lowest lung function (forced expiratory volume of 81.5 percent) while those living the farthest from a roadway had the highest lung function (forced expiratory volume of 89.7 percent).

Excluding individuals with rhinitis alone, factoring in the effects of lower socioeconomic status, smoking, and obesity, did not significantly alter the findings. However, the researchers found no association between traffic exposure and quality of life measures.

The investigators highlight the need for further confirmation of these findings, as well as continued research into the mechanisms by which traffic emissions impact lung function.

SOURCE: Journal of Allergy and Clinical Immunology, April 2009.