Freeway proximity can put you on the road to heart health issues
Living near a freeway can help commuters get where they're going faster, but new research suggests that it's also likely to put people on the fast track toward heart disease. A new study by scientists at USC, UC Berkeley and research centers in Spain and Switzerland is the first to link exposure to car and truck exhaust with increased public health risk of atherosclerosis, a condition that causes artery walls to grow thick and hard. The results “suggest that air pollution may contribute to the acceleration of cardiovascular disease development – the main causes of morbidity and mortality in many countries.”
The study was performed in the Los Angeles area, where the scientists recorded the correlation between subjects' proximity to traffic-related pollution, and the progression of common carotid artery intima-media thickness (CIMT). Ultrasounds were used to measure artery wall thickness in almost 1,500 people living within 100 meters of L.A. Freeways, every six months for three years. The progression of the participants' arterial wall hardening was found to happen at about double the average rate.
In addition to possibly causing heart disease and stroke, Southern California freeways and traffic have long been thought to be responsible for high rates of asthma and respiratory diseases. According to the California Department of Public Health, “Over five million Californians have been diagnosed with asthma in their lifetime and more than half of them have an asthma attack each year. Asthma reduces the quality of life for millions of people and causes considerable economic costs for California.”
The Environmental Protection Agency has launched a major study into the health effects of children living near freeways and major roadways in the Detroit area, in conjunction with the University of Michigan, that plans to address, among other questions: “Which measures of traffic-associated pollution are most closely associated with asthma aggravation? Which characteristics of roadway-associated pollution are most strongly associated with markers of inflammation and oxidative stress in asthmatic children, and do these relationships vary by the type of traffic or characteristics of the child? Does traffic exposure influence the likelihood or severity of respiratory viral infections? What degree of exposure misclassification is attributable to the use of community monitoring as a surrogate for individual exposures, as compared to the use of indoor monitoring and individualized exposure modeling, and what impact does this have on point estimates and confidence intervals for measures of association between exposures and key health outcomes?”
But this latest study confirms that we need to begin looking at the other public health effects of freeways – and not just asthma and breathing problems. The study ends with this warning: “Future studies should investigate whether atherogenic effects of air pollution may be larger in women, among the socially deprived or poorly educated, and possibly among those under treatments that interact with atherogenic pathways. The issue is of substantial public health relevance due to the high burden of morbidity and mortality related to atherosclerosis, and the very high number of people exposed to ambient air pollutants through the entire lifecourse.”