Bad Air Days Send Elderly to Hospitals

March 7, 2006 -- Bad air days drive elderly people to the hospital, a new study shows.

The culprit: microscopic air pollution particles that work their way deep into the lungs. The study, by Johns Hopkins researcher Francesca Dominici, PhD, and colleagues, links this fine-particulate air pollution to hospital admissions for heart failure and lung disease in Americans over age 65.

The highest risk was for heart failure. Nationwide, hospital admissions for heart failure went up 1.28% for every 10 units of fine-particulate air pollution. Air pollution containing more than 40 units of this kind of pollution triggers an "unhealthy for sensitive groups" or higher warning on the U.S. Air Quality Index.

"Our findings indicate an ongoing threat to the health of the elderly population from airborne particles," Dominici and colleagues write.

The study appears in the March 8 issue of The Journal of the American Medical Association.

Fine-Particulate Air Pollution: Threat and Menace

Air pollution is mostly ozone and specks of grime. The smaller these specks of particulate pollution, the more deadly they appear to be. That's because they penetrate deep into the body.

Since 1999, the U.S. has tracked the smallest of these particles using monitors scattered throughout the nation. Dominici's team cross-referenced these data with hospital admissions reported to Medicare in 204 urban counties.

Among people over age 65, fine-particulate air pollution was linked to hospitalization for many different kinds of heart disease, heart-rhythm problems, heart failure, chronic obstructive pulmonary disease (such as emphysema), and respiratory infections.

"Overall, we found evidence of an association between recently measured [fine-particulate] concentrations and daily hospitalizations on a national scale," Dominici and colleagues write.

The researchers call for further research to find out exactly what it is about these particles that make them so toxic. And they call on the U.S. to set air-quality standards that, for elderly people, "is as protective of their health as possible."