Traffic air pollution has been linked to poor health in the past - with wheezing, coughing, and watery eyes just the tip of the iceberg. Later studies have also established a relationship between pollution and a host of heart problems, including left ventricular hypertrophy and heart failure, among others. However, a new study, from the University of Washington's Medical Center in Seattle, has now found that air pollution emitted from traffic sources also changes the structure of the heart's right ventricle - further increasing the risk of heart failure for residents' of pollution-dense areas. 

"Although the link between traffic-related air pollution and left ventricular hypertrophy, heart failure, and cardiovascular death is established, the effects of traffic-related air pollution on the right ventricle have not been well studied," said the study's lead author Peter Leary, MD, MS, of the UW Medical Center in a press release. "Using exposure to nitrogen dioxide as a surrogate for exposure to traffic-related air pollution, we were able to demonstrate for the first time that higher levels of exposure were associated with greater right ventricular mass and larger right ventricular end-diastolic volume. Greater right ventricular mass is also associated with increased risk for heart failure and cardiovascular death."

The study observed the health patterns of 3,896 individuals who participated in the Multi-Ethnic Study of Atherosclerosis, each of whom had no prior history of cardiac disruption or disease. All of the test subjects had previously undertaken magnetic resonance imaging (MRI) scans, with authors observing their levels of exposure to pollutant nitrogen oxide in the year leading up to the scan.

On average, the study found that a higher incidence of exposure to nitrogen oxide coincided with a five percent increase (around one gram) in right ventricular mass and a three percent increase (4.1 mL) in  right ventricular end-diastolic volume. The researchers combed through a range of differentiating factors that could have skewed the data before confirming their findings, including variations in lung disease, socioeconomic standing, inflammation, and left ventricular mass and volume. 

"The morphologic changes in the right ventricle of the heart that we found with increased exposure to nitrogen dioxide add to the body of evidence supporting a connection between traffic-related air pollution and cardiovascular disease," said Leary. "The many adverse effects of air pollution on human health support continued efforts to reduce this burden." 

It should be noted, however, that while increased exposure to nitrogen oxide led to a notable change in the heart's structure, the findings have not definitively been linked to traffic air pollution. However, the researchers are confident that these recent findings are aligned with previous studies on the matter, and serve to strengthen beliefs that traffic air pollution is detrimental to cardiovascular health. 

The study was published in the American Journal of Respiratory and Critical Care Medicine.

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