Researchers reported at the American Heart Association's 49th Annual Conference on Cardiovascular Disease Epidemiology and Prevention that people who have had a heart attack are likely to report having been in traffic shortly before their symptoms began.
In the German study of patients who had a heart attack, researchers found the patients to be more than three times as likely to have been in traffic within an hour of the onset of their heart attack.
The researchers also observed small but statistically significant increases in the chance that a heart attack occurred within six hours after exposure to traffic.
Time spent in any mode of transportation in traffic was associated with a 3.2 times higher risk than time spent away from this trigger. Females, elderly males, patients who were unemployed, and those with a history of angina were affected the most by traffic.
"Driving or riding in heavy traffic poses an additional risk of eliciting a heart attack in persons already at elevated risk," said Annette Peters, Ph.D., lead author of the study and head of the research unit at the Institute of Epidemiology, Helmholtz Zentrum Muchen, Germany.
"In this study, underlying vulnerable coronary artery disease increased the risk of having a heart attack after driving in traffic," the expert added.
To reach the conclusion, researchers reviewed cases of heart attack through the KORA registry in Augsburg, Southern Germany between February 1999 and December 2003. They used a standardized interview with 1,454 patients to collect data on potential triggers of heart attack, including exposure to traffic in the four days prior to heart attack symptom onset.
The patients had a known date and time of heart attack and all had survived 24 hours after the heart attack. Participants were asked what they did the day of the heart attack, where they went, the means of transportation and time spent in traffic.
he average age of the participants was 60 years and about 25 percent were women.
The study showed that about 8 percent of the heart attacks in the group were attributable to traffic, Peters said.