MONDAY, May 10, 2010 (HealthDay News) -- There's growing proof that air pollution is associated with heart attack, stroke and cardiovascular death, says an updated American Heart Association (AHA) scientific statement released Monday.
Of the different types of air pollution, the evidence is strongest for fine particulate matter (called PM2.5 by scientists because the particles have a diameter of 2.5 micrometers or less). Its tiny size makes it more likely to infiltrate even the smallest airways, and according to the experts who wrote the updated statement, it's the type of air pollution most likely to cause cardiovascular disease.
Major sources of PM2.5 include fossil fuel combustion from industry, traffic and power generation.
"Particulate matter appears to directly increased risk by triggering events in susceptible individuals within hours to days of an increased level of exposure, even among those who otherwise may have been healthy for years," statement lead author Dr. Robert D. Brook said in an AHA news release.
"Growing evidence also shows that longer-term PM2.5 exposures, such as over a few years, can lead to an even larger increase in these health risks," he added. As a result, the AHA stated that fine particulate matter "should be recognized as a 'modifiable factor' that contributes to cardiovascular morbidity and mortality."
Those at highest risk from PM2.5 exposure include the elderly, people with existing heart diseases (for example, heart failure or coronary artery disease), and possibly those with diabetes.
"The foremost message for these high-risk groups remain that they should work to control their modifiable traditional risk factors -- blood pressure, cholesterol, diabetes, [and] smoking," said Brook, a cardiovascular medicine specialist at the University of Michigan, Ann Arbor. In addition, he wrote, people can limit their exposure to PM2.5 pollution "by decreasing their time outside when particle levels are high and reducing time spent in traffic."
He and colleagues also concluded that there is:
- Strong level of evidence of a link between air pollution and ischemic heart disease (a narrowing of the coronary arteries that prevents adequate blood supply to the heart).
- Modest level of evidence that air pollution is associated with peripheral vascular diseases, irregular heartbeats and cardiac arrest.
- A "moderate, yet growing link" between air pollution and heart failure and ischemic stroke (a stroke caused by an interruption on the blood flow to the brain).
- A "small yet consistent" association between short-term exposure to air pollution and premature death.
The updated statement appears online May 10 in the journal Circulation.
The U.S. Environmental Protection Agency has more about particulate matter and health.