Air Pollution Triggers Heart Attacks
The dirtier the air, the more likely people are to suffer sudden cardiac arrest.
Particulate matter - tiny specks of soot, dust, and other pollutants in the air that can be breathed deep into the lungs - has been consistently linked to increases in deaths from heart disease and clogged arteries. But studies looking at whether air pollution specifically raises the risk of heart attack or cardiac arrest have had mixed results. Airborne particles are harmful to people with existing health problems but they could also trigger heart attack or even sudden death in people with no apparent symptoms of cardiovascular disease.
To investigate, researchers looked at 8,434 cases of sudden cardiac arrest among people 35 years and older that occurred in metropolitan Melbourne between 2003 and 2006.
After a rise in concentration of the tiniest airborne particles (particles less than 2.5 microns across, known as PM2.5), the likelihood of cardiac arrest rose, and stayed higher than average for two days. For every 4.26 micrograms per cubic meter increase in PM2.5 concentrations, the risk of cardiac arrest was 4 percent higher than average for the next 48 hours.
Carbon monoxide levels also were associated with increases in cardiac arrest risk, although the effect wasn't as strong as it was for PM2.5. None of several other pollutants the researchers measured, including larger airborne particles, affected risk. The effect was strongest for people 65 to 74 years old, and weakest for those 75 and older.
June 16, 2010