Sorensen and her team also studied how much air pollution the study participants experienced, but Sorensen said those results will be published in a separate study later on.
The people who had heart attacks in the study were at greater risk from other factors as well: They smoked more, were less physically active and had poorer diets. Although the researchers tried to rule out those factors in their statistical analysis, it's often difficult for researchers to rule out absolutely every variable that might affect an association between two factors, even when using the best statistical methods. Dr. David Frid, a cardiologist at the Cleveland Clinic, said it's hard to discount how other cardiovascular risk factors may have affected the study participants who had heart attacks.
"Cardiovascular disease is a complex process and there are multiple factors that could lead to a heart attack," Frid said. "As we identify these various factors, we have to then be cognizant of what we can do to ultimately reduce our risk of developing heart disease."
It may not always be possible for people to escape the noisy environment they live in, so those who hear lots of horns honking and brakes squealing night and day may need to step up their efforts to get regular exercise and eat a healthy diet to compensate for that risk.
"Ultimately, if you're living in a place with a lot of noise, it could potentially put you at higher risk, but we don't know whether reducing that noise reduces your risk," Frid said.