Residing near major routes may impact heart attack survivors
MedWire News: Living too close to a major road at the time of a heart attack may shorten the life expectancy of survivors, suggest study results published in Circulation.
"Living close to a highway is associated with adverse cardiovascular outcomes in those with underlying cardiac disease," said lead author Murray Mittleman (Harvard Medical School, Boston, Massachusetts, USA) in a press statement.
"Besides air pollution, exposure to noise could be a possible mechanism underlying this association," he suggested.
Mittleman and co-authors enrolled 3886 US patients admitted to hospital for acute myocardial infarction (AMI) between 1989 and 1996 to take part in the Onset Study. Of these, 3547 provided details of a home address and were included in the analysis.
The patients were followed up for 10 years after their initial AMI. The researchers assessed whether the proximity of the participants' residential address to a major road influenced their mortality rate.
After 10 years follow up, 1071 patients had died. Of these, 63% were from cardiovascular disease, 12% from cancer, and 4% from respiratory disease.
After adjusting for age, gender, education, distance to nearest acute care hospital, smoking status, body mass index, number of comorbidities, and prescribed medications, among other factors, the team found that people who lived within 100 m of a major road at the time of AMI were a significant 27% more likely to die during the follow-up period than those who lived 1000 m or more away from a major road.
The risk decreased with increasing distance between the dwelling and the road. For example, people who lived 100-200 m away from a major road had a 19% increased mortality and those living 200-1000 m away a 13% increased mortality over 10 years compared with those living 1000 m away or more, although these increases were only of borderline significance.
"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," commented Mittleman.
These findings add to those of previous studies that have shown an increased risk for stroke and other cardiovascular events in patients living close to major roads.
"On a public policy level, city planners should consider locating housing developments away from the most heavily trafficked roadways," suggested Dan Costa, US Environmental Protection Agency, who was not involved with the research.
"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," he added.
By Helen Albert