The new study found that living within 50 m (164 ft) of a major roadway increases risk of sudden cardiac death by 38% in women.
The researchers - led by Jaime E. Hart from Brigham and Women's Hospital and Harvard Medical School in Boston, MA - publish their findings in the journal Circulation.
According to the Centers for Disease Control and Prevention (CDC), heart disease is the leading cause of death for women in the US and killed over 292,000 women in 2009 - accounting for 1 in every 4 female deaths.
Additionally, around 64% of women who die suddenly of coronary heart disease have not had any previous symptoms, which means that even in the absence of symptoms, many women may be at risk for heart disease.
"It's important for health care providers to recognize that environmental exposures may be under-appreciated risk factors for diseases such as sudden cardiac death and fatal coronary heart disease," says Hart.
As such, he and his colleagues studied data from over 107,000 women who had an average age of 60 and who were mostly white, as part of the Nurses' Health Study from 1986-2012.
'Exposure to roadways comparable to smoking, diet or obesity'
The researchers say previous studies have found a slight increase in coronary heart disease risk among individuals living near major roadways, but theirs is the first to examine the effect of roadway proximity on sudden cardiac death risk.
After calculating the participants' distance to roadways and adjusting for other factors, the researchers found that living within 50 m (164 ft) of a major road increased sudden cardiac death risk by 38%, compared with those who lived at least 500 m (0.3 miles) away.
Additionally, each 100 m (328 ft) closer a participant lived to major roadways increased her risk for sudden cardiac death by 6%.
"On a population level," says Hart, "living near a major roadway was as important a risk factor as smoking, diet or obesity." The researchers note that the Environmental Protection Agency (EPA) reported 35 million people in the US lived within 300 m (984 ft) of a major road in 2009.
Though their study involves a large number of participants, the researchers say they were unable to measure all possible risk factors associated with living near major roadways. As such, they say more research is needed that includes men and women of different ages, races and income levels, given their limitation that most participants were middle-aged or elderly, white and in the middle- and upper-socioeconomic classes.
Commenting on their study, Hart says:
"Regardless of where you live, adopting heart-healthy habits, such as maintaining a healthy weight, being physically active, eating nutritious foods, quitting smoking and managing stress can help decrease your risk of heart and blood vessel disease."
He adds that they next plan "to determine what specific exposures, such as air pollution, are driving the association between heart disease and major roadway proximity."
Medical News Today recently reported on a study that suggested trees save 850 American lives each year by directly removing air pollutants.