Heart attack death rates higher when patient lives near highway

Major highways pose a considerable risk to heart attack survivors living in close vicinity. Findings of the study, published in the May 7 issue of Circulation, report that researchers from the Beth Israel Deaconess Medical Center conclude that housing developments need to be isolated from areas with heavy traffic. The study demonstrated that the risk for heart attack survivors living within 100 meters (328 feet) or less from a roadway is 27% higher over a period of 10 years, as compared with those who live at least 1,000 meters away. This risk is reduced to 13% for survivors living between 200 and 1,000-meter (656 to 3,277-feet) from the roadway. Murray Mittleman, MD, DrPH, a physician in the CardioVascular Institute at Beth Israel Deaconess Medical Center, who is also an Associate Professor of Medicine at Harvard Medical School and a director of BIDMC's cardiovascular epidemiological research program, explained: "Living close to a highway is associated with adverse cardiovascular outcomes in those with underlying cardiac disease. Besides air pollution, exposure to noise could be a possible mechanism underlying this association." Over a 10-year period, researchers from the Onset study that included 3,547 heart attack survivors in 64 community hospitals and tertiary care medical centers recorded 1,071 deaths, of which 63% were due to cardiovascular disease, whilst 12% died of cancer and 4% from respiratory disease. Factors including the deceased's personal, clinical and neighborhood-level characteristics, such as income and education were evaluated. Mittleman says: "People with lower levels of education and income are more likely to live in communities closer to a major roadway, so they are bearing a larger burden of the risk associated with exposure than people with more resources." Mittleman led a study published earlier this year, which provided evidence that air pollution, even at levels generally deemed as safe according to federal regulations, increases the risk of stroke by 34%. His study furthermore revealed that exposure to ambient fine particulate matter, commonly from vehicle traffic, was linked to a considerably higher risk of ischemic strokes on days when the EPA's air quality index for particulate matter was yellow instead of green. These results offer new evidence that a higher mortality risk of patients with underlying cardiovascular disease is linked to long-term exposure to roadways. Mittleman declares: "Clinicians need to educate their patients on the risks posed by particulate matter pollution and encourage patients with cardiovascular disease to avoid unnecessary exposure to traffic. On a public policy level, city planners should consider locating housing developments away from the most heavily trafficked roadways." Dan Costa, ScD, DABT, National Program Director for Air Climate & Energy Research in U.S. Environmental Protection Agency Office of Research and Development Research concludes: "This study adds to the growing knowledge linking roadways and traffic to health problems, even death, especially among those with pre-existent disease - in this case a previous heart attack."