Older adults with long-term exposure to higher levels of pollution are at higher risk for hospitalization for pneumonia, according to researchers in Canada.
"Our study found that among older individuals, long-term exposure to traffic pollution independently increased their risk of hospitalization for pneumonia," said principal investigator, Mark Loeb, M.D., of McMaster University.
The research will be published in the January 1 issue of the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
Pneumonia is a leading cause of sickness and death among older adults, and rates of hospitalizations for pneumonia among patients 65 and older have been increasing in recent years.
In addition to traffic pollution associated with roads, Hamilton has a large industrial steel-making complex in the north end of the city, creating a large exposure zone for residents. The researchers recruited 365 older adults from Hamilton, Ontario, who had been hospitalized with radiologically confirmed pneumonia in one of Hamilton's four emergency departments between 2003 and 2005. Control subjects from the same catchment areas as the patients were enrolled contemporaneously, and then compared their exposures to nitrogen dioxide (NO2), sulfur dioxide (SO2), and fine particulate matter less that 2.5 μm (PM2.5) using data from air-quality monitoring stations and land use regression models.
The researchers found that long-term (more than 12 months) exposures to NO2 and PM2.5 were each associated with a more than doubled risk of hospitalization from pneumonia. Individuals with long-term exposure to NO2 had 2.3 times the risk for hospitalization with pneumonia; for PM2.5, the odds ratio was 2.26.
"We postulate that long-term exposure to air pollution may have increased individuals' susceptibility to pneumonia by interfering with innate immune defenses designed to protect the lung from pathogens;
|Contact: Keely Savoie|
American Thoracic Society