First posted on 04-18-2013
Over the years, a number of studies described various associations between road traffic and heart disease. Last year, one such study even demonstrated a link between traffic noise and the probability of suffering a heart attack.
The latest study shows that long-term exposure to the type of fine particulate matter produced by traffic is directly linked to atherosclerosis, even when traffic noise is discounted.
Dr. Hagen Kälsch from the West-German Heart Center said that the study was designed to establish the causal relationship between vehicle traffic and heart attack risk. Researchers wanted to know whether particle pollution, noise, or some combination of the two were to blame.
The newest study used data from the German Heinz Nixdorf Recall Study, which included detailed information on over 4000 participants with a mean age of 60. The new study considered the participants’ proximity to roads with high traffic, exposure to particle pollutants, and exposure to traffic noise. Doctors measured the amount of calcification in the participants’ blood vessels, a common marker of atherosclerosis.
Results showed that proximity to roads and exposure to small particulate matter increased calcification. In fact, every increase in particle volume resulted in calcification going up by 20.7 percent. In addition, each 100 foot distance closer to traffic increased calcification by 10 percent. Evening traffic noise levels impacted calcification by 3.2 percent for every 5 decibel increase.
According to Kälsch, the study confirms that long-term exposure to fine particle pollutants and to traffic noise are independently connected to blood vessel calcification.
“These two major types of traffic emissions help explain the observed associations between living close to high traffic and subclinical atherosclerosis,” Kälsch said. “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.”
Researchers believe that both traffic noise and fine particle pollutants effect similar biological pathways in the human body. Both appear to disrupt the autonomic nervous system, causing an imbalance. The autonomic nervous system is part of a complex series of mechanisms the body uses to regulate blood pressure, glucose levels, blood clotting and blood viscosity.
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