SOURCE: Intermountain Medical Center Heart Institute, news release, Nov. 8, 2015
SUNDAY, Nov. 8, 2015 (HealthDay News) -- Air pollution increases the risk of a serious heart attack for those who have heart disease, a new study suggests.
Researchers examined data on thousands of people treated for heart attack in and around Salt Lake City between 1993 and 2014. Their aim was to see how air pollution affects heart attack risk and which type of heart attack in particular.
The study found a strong association between bad air quality -- above 25 micrograms of fine particulate matter per cubic meter of air -- and increased risk of STEMI heart attack, the most dangerous type of heart attack. But the study did not prove that poor air quality causes this type of heart attack.
STEMI heart attack occurs when a heart artery is completely blocked and a large portion of the heart muscle can't receive blood. Without quick treatment, a patient can suffer irreparable heart damage or death, the researchers explained.
"Our research indicated that during poor air quality days, namely those with high levels of PM2.5, patients with heart disease are at a higher risk of suffering from a STEMI heart attack," study author Dr. Kent Meredith, a cardiologist at the Intermountain Medical Center Heart Institute in Salt Lake City, said in an institute news release.
"By making this association, physicians can better counsel their heart patients to avoid exposure to poor air quality, and thus decrease their chances of suffering a heart attack on days that they are potentially at highest risk," he added.
The researchers advised heart patients to become familiar with the color-coded Air Quality Index. Yellow means the air is moderately healthy, orange is unhealthy for sensitive groups, and red is unhealthy.
"The study suggests that during many yellow air quality days, and all red quality air days, people with known coronary artery disease may be safer if they limit their exposure to particulate matter in the air by exercising indoors, limiting their time outdoors, avoiding stressful activities, and remaining compliant with medications," Meredith said.
"These activities can reduce inflammation in the arteries, and therefore make patients less sensitive to the fine particulate matter present on poor air quality days," he concluded.
The study was to be presented Sunday at the American Heart Association's annual meeting in Orlando, Fla.
Data and conclusions presented at meetings have not been through the rigorous peer review required of published studies and should be considered preliminary.
The American Heart Association has more about air pollution and heart disease.