Heart attack risk increased by air quality, study reveals

Coronary heart disease takes the lives of about 380,000 people yearly according to The Heart Foundation, and for those who have a preexisting condition, they are more at risk for a heart attack if they are living in polluted area, or a place where air quality is often low, researchers find.

Eurekalert reports that researchers from the Medical Center Heart Institute in Salt Lake City presented a major new study at the American Heart Association Scientific Session in Orlando, where they found that those with heart disease are at higher risk for a heart attack on days when air quality is poor.

Researchers studied over 16,314 patients who have suffered three types of heart attacks, STEMI (ST-segment elevation myocardial infarction), non-STEMI, and unstable angina from 1993 to 2014, and identified which type was more common on days when the air was filled with pollutants. Considered the most severe type of heart attacks, STEMI is when a whole artery is blocked, causing a large portion of the heart muscle to thicken and possibly die of lack of oxygen.

Medical Daily reports that according to lead author Dr. Kent Meredith, "Our research indicated that during poor air quality days, namely those with high levels of PM 2.5, patients with heart disease are at a higher risk of suffering from a STEMI heart attack."

PM2.5 is when air pollution contians fine particles that are tinier than 2.5 millimeters in diameter, like soot and car exhaust. Researchers claim that exposure to this type of pollutions is linked to chronic health problems and premature death.

Through the data gathered, researchers determined the air quality of the area in which patients experienced heart attacks. Researchers found no links between air quality and the occurrence of heart attack in patients with no history of coronary artery disease (CAD), but found that patients who had a history of CAD were at 15% more risk for a STEMI heart attack when they were exposed to over 25 micrograms of fine particulate matter per cubic meter of air.

"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," Dr. Meredith explained. "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."

The Salt Lake Tribune reports that according to cardiologist John Ryan from the University of Utah, "These are important findings that are additive to what we've found previously on heart disease and air quality."