Air Pollution Rivals Exertion and Booze as a Trigger of Heart Attacks
By Matthew Heller on February 25, 2011
European researchers have concluded that air pollution directly leads to about as many heart attacks as better-known triggers such as physical exertion and excessive drinking.
In a study published in the journal The Lancet, researchers said that the main reason for the widespread impact of air pollution is its pervasiveness. Everyone is exposed to dirty air. So, even though air pollution poses a relatively low risk to any single person, it was estimated to be the trigger for 5 percent to 7 percent of all heart attacks.
Cocaine, by contrast, increases an individual’s immediate heart attack risk by an alarming 2,400 percent. Still, given the comparatively small numbers of people exposed to cocaine, the study found that it accounted for only 0.9 percent of heart attacks.
“The important message here is that while an individual’s risk from air pollution is moderate or small, each of us is exposed, making the amount of risk intolerable for the entire community,” Dr. Andrea Baccarelli of the Harvard School of Public Health, who wrote an editorial that accompanied the study, told The Boston Globe.
Baccarelli said air pollutants may trigger heart attacks by promoting inflammation and increasing blood clotting. Pollutants also appear to attach to lung cell receptors, sending a signal to the heart that the body is in trouble.
The researchers from Belgium and Switzerland who conducted the study reviewed 36 epidemiological assessments to assess the importance and relevance of “final straw” risk factors for heart attacks — as opposed to their longer-term causes.
Traffic exposure was judged to be the top factor, accounting for 7.4 percent of heart attacks. Researchers acknowledged that the traffic figure could be related to exposure to air pollutants, or to other commuting issues such as stress and noise, but said they lacked the data to clarify the possible connections.
Along with traffic exposure and air pollution, physical exertion, alcohol and coffee were rated among the leading triggers, all thought to account for 5 percent or more of heart attacks. As for sexual activity, it rated well behind, accounting for 2.2 percent.
The study was published Thursday, a day after the U.S. Environmental Protection Agency announced that it was easing rules to crack down on air pollution from industrial boilers and incinerators