Air Pollutants Promote Heart Attacks

Long-term exposure to particulate matter is associated with an increased risk for heart attack. Moreover, this association can already be observed in levels of particulate exposure below the current specified European limit values.  Annette Peters, of Helmholtz Zentrum Munchen (Germany), and colleagues analyzed data collected on 100,166 men and women residing in Finland, Sweden, Denmark, Germany, and Italy.  At the study’s start, all participants were free from cardiovascular diseases. The participants were followed for incident coronary events for an average period of 11.5 years.  The researchers then compared event incidence to concentrations of particulate matter with a diameter less than 10 micrometers (PM10) and inhalable particles smaller than 2.5 micrometers (PM2.5), and nitrogen oxides (NOx) at the residence location.  During the study period, a total of 5,157 individuals suffered a heart attack or unstable angina pectoris, both generally caused by calcification of the coronary vessels. An increase of 5 micrograms/m2 of annual concentration of PM2.5 or 10 micrograms/m2 of PM10 in the ambient air led to a 13 and 12% increased risk of heart attack, respectively. Importantly, the risk remained elevated even at levels below the current EU limit values of 25 micrograms /m2 for PM2.5 and 40 micrograms /m2 for PM10.  The study authors write that: “Long term exposure to particulate matter is associated with incidence of coronary events, and this association persists at levels of exposure below the current European limit values.”