Where You Recover From a Heart Attack Matters

It you're unfortunate to suffer a heart attack, pray it's in a city with clean air. That's the message from a pair of epidemiologists at the Harvard School of Public Health. How long you survive upon release from the hospital, and how well you recover, they find, can both be greatly affected by the amount of fine dustlike particles suspended in the air.

Antonella Zenobetti and Joel Schwartz collected Medicare data on 196,000 heart-attack survivors 65 and older who had been discharged from hospitals 1985 and 1999. They resided in 21 U.S. cities that ranged in size from Chicago to Youngstown, Ohio, and spanned the country from Honolulu to New Haven, Conn. The researchers then correlated long-term air-pollution data for each city--throughout the period following each individual's release from the hospital and for years afterward--with that individual's survival and any subsequent heart attacks or hospital admissions for congestive heart failure.

The scientists took into account factors that might affect survival--independent of any effect of pollution--such as age, type of heart attack suffered, the presence of diabetes or any of several other co-existing diseases, and time spent in the hospital during recovery.

In the May Environmental Health Perspectives, the authors note that theirs is the "first long-term study that investigated persons discharged alive following an acute myocardial infarction [heart attack]." The chief finding: survival was significantly diminished by coming home to breathe air polluted with substantial concentrations of particulates. They focused on values for particulates 10 micrometers in diameter or smaller, since these are the ones that are small enough to be inhaled deeply and to lodge in the lungs' tiniest airways--those that transfer oxygen to the bloodstream.