Exposure to traffic pollution and noise can in the long run lead to atherosclerosis, according to a German study which for the first time explored the links between the two.
The study, which was based on data from the German Heinz Nixdorf Recall Study, calculated the long-term exposure to particle pollutants of 4,814 participants who live nearby roads with high traffic volume.
The results were presented at a European Society for Cardiology event in Rome on Thursday (18 April).
For the first time, the cardiological study also took account of road traffic noise and its effect on cardiovascular diseases, as recorded by validated tests.
The test group's level of atherosclerosis was then evaluated by measurement of vascular vessel calcification in the thoracic aorta by computed imaging.
Results showed that in 4,238 subjects small particulate matter and proximity to major roads were both associated with an increasing level of aortic calcification. For every increase in particle volume up to 2.4 micrometres, the degree of calcification increased by 20.7% and went up an extra 10% for every 100 metre of proximity to heavy traffic.
Traffic noise associated with increased risk of heart attack
The study also found a increase in atherosclerosis associated with night time noise.
Dr Hagen Kälsch from the West-German Heart Centre in Essen said that long-term exposure to fine particle matter air pollution and to road traffic noise are both independently associated with subclinical atherosclerosis.
"These two major types of traffic emissions help explain the observed associations between living close to high traffic and subclinical atherosclerosis. The considerable size of the associations underscores the importance of long-term exposure to air pollution and road traffic noise as risk factors for atherosclerosis," Kälsch said.
The association between road traffic and heart disease has been suggested in previous studies.
In 2012 a study from Denmark showed that traffic noise was significantly associated with risk of heart attack. For every 10 decibel increase in noise exposure, there was a 12% increased risk, the study found.
Fine particle matter and traffic noise are believed to act through similar biologic pathways, thereby increasing cardiovascular risk.
They both cause an imbalance in the autonomic nervous system, which feeds into the complex mechanisms regulating blood pressure, blood lipids, and glucose level.