Traffic pollution triggers risk of heart attack for up to six hours after exposure, finds a new research published in the British Medical Journal.
Dr. Krishnan Bhaskaran and colleagues reviewed 79,288 heart attack cases from the year 2003 to 2006. Research team compared recorded time of each heart attack with information of their regional air pollution (taken from the U.K. National Air Quality Archive). Pollutant particles (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), sulphur dioxide (SO2) and ozone are the pollutants that were investigated. Amongst them higher levels of pollutant particles and nitrogen dioxide are the main markers of traffic related pollution.
Researchers found that traffic pollutant doesn’t increase overall risk of heart attack. Instead the risk was transient and remained only for one to six hours. After 72-hours period after exposure, none of the five pollutants were found associated with high risk of heart attack. However, risk of cardiac events precipitate in people who were already at risk.
High level of nitrogen dioxide exposure for 1–6 hours was associated with increase in short-term risk of myocardial infarction.
Researchers of the study say that traffic pollution can boost risk of heart attacks through various mechanisms. Pollutants increase inflammation, blood “stickiness” and increase blood pressure. As a result person becomes more prone to heart diseases.
Since pollution was not found to increase heart attack risk for broader timescale. Researchers of the study said that heart attacks in the research sample would have happened anyway but it was due to pollution that they happened earlier. Therefore the people with increased risk of heart attack are advised to avoid prolonged and frequent exposure to high traffic pollution.
Till now the established researches have seen traffic pollution to be responsible for premature death from heart disease. But there were only few studies that have studied level of exposure to heart diseases. This study has significantly contributed to this research area.
The study examined individual susceptibility to cardiovascular events during high PM10 levels.read more
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