Traffic fumes advance heart attacks: Study

The researchers have based their findings on an analysis of almost 80,000 heart attack cases and the level of pollution to which they were exposed.

In the study, they found rising air pollution was linked to a rise in heart attacks up to six hours after exposure. But there was no increased risk after the six-hour period, with the number of heart attacks then falling to a lower level than expected, the Daily Mail reported.

The researchers reviewed 79,288 heart attack cases from 2003 to 2006 and exposure, by the hour, to pollution levels. They used the UK National Air Quality Archive to investigate the levels of specific pollutants in atmosphere.
These included pollutant particles (PM10), carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ozone.

Higher levels of PM10 — tiny toxic particles — and NO2 are well-known markers of traffic related pollution from vehicle exhaust fumes, said Dr Bhaskaran.

He estimated there would be an extra five per cent risk of a heart attack caused by a change in air pollution from “low” to “moderate” in the following six hours.

The risk would increase further during “high” and “very high” episodes but they’re uncommon in Britain,says the study.

Dr Bhaskaran said the data suggested that after the first six hour period following pollution peaks, the number of heart attacks was lower than expected.

He added: “Some people who were going to have a heart attack in that later period may have simply had their heart attack brought forward by a few hours as result of the pollution exposure.

“We know from many studies that there are more deaths when pollution levels are higher, but whether heart attacks make a major contribution to this is not clear.

“Although we found a short period of increased risk of heart attacks in the few hours after air pollution peaks, the risk was small and had little net impact on the overall number of heart attacks.”