Traffic fumes may trigger heart attack: Study

Washington, March 15: A new study has given evidence that inhaling the ultra fine particles of traffic pollution can trigger a heart attack in susceptible people.

Researchers from Germany analyzed 1,500 heart attack cases and discovered that most of the heart patients had been in heavy traffic under an hour before experiencing a heart attack.

They were either driving, riding public transport or cycling. In short, those who spent time in traffic, irrespective of the mode of transportation, faced a 3.2 times higher risk of heart attack.

Annette Peters, head of the Institute of Epidemiology in Helmholtz Zentrum Munchen, Germany, and an associate professor in Harvard's School of Public Health, said, "For someone with a very low risk for a heart attack, this doesn't mean much. But for someone already at a higher risk for a heart attack -- because of lifestyle issues such as smoking or being overweight or perhaps because of genetic makeup -- then traffic might be an additional stressor that could cause a heart attack to occur at this time."

Exposure to traffic was particularly harsh on patients with a history of angina, women, elderly men and the unemployed. Women appeared to face a five times higher risk. However, the researchers admitted that the elevated risk in women may be because of physiological differences, or due to the smaller number of women included in the study.

The link between air pollution and heart problems has been established by previous studies as well. Pollution produced by car engines can get past the normal defense mechanisms in the lungs and penetrate deeply into the air exchange regions.

Dr. Gregg C. Fonarow, a professor of cardiology at the University of California, Los Angeles stated, "This data is very consistent with reports that this kind of exposure leads to inflammation, cholesterol build-up in the arteries and heart attacks, although there's also a lot of data about stress and its connections to heart attacks. So, probably both of these factors are working synergistically to raise the cardiovascular risk."

However, Fonarow also suggested that although the relative risk for heart attack was high following traffic exposure, it's important to keep in perspective the absolute risk, which was actually very, very small. “Meaning, that given the number of times individuals are exposed to traffic and do not have heart attacks, these findings should not alarm the average person, because in absolute terms, the risk that being exposed to traffic every day will provoke a heart attack is exceptionally low.”

The results of the study were presented at the American Heart Association's 49th Annual Conference on Cardiovascular Disease Epidemiology and Prevention in Florida.