WEDNESDAY, Feb. 20 (HealthDay News) Exposure to smog is linked to higher death risk among people admitted to the hospital for a heart attack, a new study suggests.
British researchers found death rates for these patients increased following exposure to air pollution from fine "particulate matter" measuring 2.5 micrometers in diameter or less. They calculated that death rates would drop by 12 percent among heart attack survivors if they were not exposed to higher concentrations of air pollution.
In conducting the study, the researchers examined the medical records of more than 150,000 people who were hospitalized for a heart attack between 2004 and 2007. They also analyzed the average air pollution concentrations from 2004 to 2010.
The participants were followed until the study ended in 2010, or until they died. Researchers took into account their gender, age, medical history, treatments, medications and whether they smoked. Participants' income, education, job and where they lived were also considered.
Over the course of the study, nearly 40,000 people died. The researchers found exposure to fine particulate matter, caused primarily by auto emissions and industry, was associated with an increase in death rates among people who had earlier survived heart attacks.
The study was published online Feb. 20 in the European Heart Journal.
"We found that for every 10 microgram per cubic meter increase in [fine particulate matter] there was a 20 percent increase in the death rate," Dr. Cathryn Tonne, a lecturer in environmental epidemiology at the London School of Hygiene & Tropical Medicine, said in a journal news release.
The highest average exposure to fine particulate matter was in London. Meanwhile, the lowest average exposure was found northeast of England. The researchers noted that exposure to air pollution varied widely within each region examined.
However, after considering o
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