Risk remains elevated even up to six hours after exposure

Sep 22, 2011 07:14 GMT  ·  By

Despite the fact that, with each year, automakers turn their attention to developing cleaner engines and even zero-emission vehicles, air pollution associated with traffic fumes is still a real concern, especially for people living in heavily concentrated urban areas.

This means people are still exposed to higher daily levels of air pollutants, which are associated with increased mortality. A recent study from the British Medical Journal now comes to further strengthen the idea that inhaling vehicle emissions increases the risk of myocardial infarction - also known as heart attack - even up to 6 hours after exposure.

While previous findings revealed that exposure to air pollution affect the human cardiovascular system 1 hour earlier, longer lags were not included, so it was not possible to say whether there would have been a subsequent reduction in risk.

The purpose of the researchers from London's School of Hygiene and Tropical Medicine was to quantify the association at an hourly temporal resolution between the risk of heart attack and exposure to traffic fumes.

The study was performed on nearly 80,000 cases of heart attacks recorded in 15 conurbations in England and Wales between 2003-2006.

As said, study results showed that higher levels of traffic related pollution were associated with short-term increases in heart attack risk 1-6 hours later. The researchers also found reductions in risk at longer lags, with no evidence of risk associated with traffic pollution over a 72 hour period after exposure.

"Given other evidence that exposure to air pollution increases overall mortality and morbidity, the case for stringent controls on pollutant levels remains strong," wrote Prof. Richard Edwards and Dr. Simon Hales from the University of Otago in New Zealand in an editorial accompanying the study.

The researchers have also revealed a number of limitations of their study, explaining that future studies will be needed to confirm their conclusions and rule out that their findings were due to chance.