Pollution and traffic noise could lead to heart failure

A new study published in the Journal of the American Heart Association found that exposure to air pollution and road traffic noise over the course of many years can increase the risk of heart failure. This association appears to be even stronger in former smokers and persons with high blood pressure.

The researchers examined the impact of long-term exposure to pollution and traffic noise on the development of heart failure in a group of 22,000 nurses in Denmark during a 15 to 20 years period.

The women were 44 years of age and older and lived in urban, sub-urban and rural areas in Denmark. At the time of enrollment in the study, participants answered questions regarding pre-existing cardiovascular conditions, body-mass index, lifestyle factors (dietary habits, smoking, alcohol consumption, physical activities), reproductive health, and working conditions.

Using a Danish air pollution modeling system, the scientists measured the annual average concentrations of two pollutants, fine particulate matter (PM_2.5) and nitrogen dioxide (NO₂). The road traffic noise levels within a three-kilometer radius from the participants’ homes were estimated through a modelling system called Nord2000.

“We found that long-term exposure to specific air pollutants and road traffic noise increased the risk of incident heart failure, especially for former smokers or people with hypertension, so preventive and educational measures are necessary,” said study lead author Dr. Youn-Hee Lim, an assistant professor of Environmental Health the University of Copenhagen. 

More specifically, the scientists found that for every 5.1 µg/m³ increase in PM_2.5 exposure over three years, the risk of incident heart failure increased by 17 percent; for every 8.6 µg/m³ increase in NO₂ exposure, the risk increased by 10 percent; and for every 9.3 dB increase in road traffic noise exposure, the risk increased by 12 percent. Moreover, former smokers exposed to fine particulate matter had a 72 percent higher risk of heart failure.

“We were surprised by how two environmental factors – air pollution and road traffic noise – interacted,” explained Dr. Lim. “Air pollution was a stronger contributor to heart failure incidence compared to road traffic noise; however, the women exposed to both high levels of air pollution and road traffic noise showed the highest increase in heart failure risk.”

“To minimize the impact of these exposures, broad public tactics such as emissions control measures should be implemented. Strategies like smoking cessation and blood pressure control must be encouraged to help reduce individual risk.”

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By Andrei Ionescu, Earth.com Staff Writer