People who are exposed to fine particle matter (PM) air pollution from traffic pollution for a prolonged period of time are at an increased risk of developing atherosclerosis, according to a new study presented at the EuroPRevent 2013 congress in Rome.

This isn’t the first time that road traffic has been linked with heart disease, a previous study conducted in Denmark in 2012 identified that traffic noise is significantly associated with risk of heart attack.

The aim of this study, as described by Dr Hagen Kälsch from the West-German Heart Center in Essen, Germany, was to see whether the increased heart risks associated with traffic came from either noise, particle pollution, or both.

The researchers used data from the German Heinz Nixdorf Recall Study, which included a total of 4,814 participants. They used street maps to calculate how near the participants were to roads with lots of traffic, chemistry transport models to estimate their exposure to pollutants, and validated tests to measure traffic noise.

Through the use of computed tomography imaging they measured vascular vessel calcification in the thoracic aorta, which revealed the patient’s level of atherosclerosis.

Increased proximity to major roads with traffic was associated with an increased level of aortic calcification in the 4,238 participants of the study. The degree of calcification increased by 20.7% as particle volume increased by 2.4 micrometers, and increased by 10% for every 100 meter proximity to heavy traffic.

Dr Kälsch confirmed that both exposure to PM air pollution as well as road traffic noise are associated with subclinical atherosclerosis.

He said:

“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.”

Traffic noise and fine PM are thought to increase cardiovascular risk by acting through similar biological pathways and causing an imbalance in the autonomic nervous system.

TAC is one of the most reliable markers of subclinical atherosclerosis, along with coronary artery calcification (CAC).

All air pollutants, including carbon monoxide (CO), nitrogen dioxide (NO2), sulphur dioxide (SO2), and particulate matter (measured as PM10) were associated with an increased risk of heart attack, except for ozone (O3).

Traffic air pollution may be particularly harmful for infants – researchers from the Karolinska Institutet, Stockholm, Sweden, reported in the American Journal of Respiratory and Critical Care Medicine, that traffic air pollution exposure during infancy harms the lungs for many years.

Written by Joseph Nordqvist