Exposure to air pollution and traffic noise over time may increase the risk of developing heart failure

Exposure to air pollution and road traffic noise for many years may be associated with an increased risk of developing heart failure, and the correlation appears to be even greater in people who are older. smokers or who suffer from high blood pressure, according to a new study. published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

We have found that long-term exposure to specific air pollutants and road traffic noise increases the risk of incident heart failure, especially for former smokers or people with high blood pressure, so preventive and educational measures are needed. . To minimize the impact of these exposures, broad public tactics such as emission control measures should be implemented. Strategies like smoking cessation and blood pressure control should be encouraged to help reduce individual risk. “

Youn-Hee Lim, PhD, lead study author and assistant professor, Section of Environmental Health, Department of Public Health, University of Copenhagen

This analysis examined the impact of long-term environmental exposure, in particular to air pollution and road traffic noise, on the development of heart failure in a group of nurses in Denmark on a period of 15 to 20 years.

The researchers collected data from a prospective study of more than 22,000 members of the Danish All-Female Nursing Cohort Study. The women were aged 44 and over at the time of enrollment in the study and lived in Denmark. The participants were recruited in 1993 or 1999, and upon registration, each woman completed a comprehensive questionnaire on body mass index, lifestyle factors (smoking, alcohol consumption, physical activity and habits. food), pre-existing health problems, reproductive health and working conditions. . Information on heart failure diagnoses was gathered throughout the 20-year follow-up by linking study participants to the Danish National Patient Register, which includes records of all healthcare provided in Danish hospitals. . Patient data was collected up to December 31, 2014.

The study group lived in rural, urban and suburban areas across Denmark. To best measure individual exposure to air pollution and road traffic noise, the researchers kept records of each individual’s residential addresses, including any moves to new residences between 1970 and 2014. For determine the levels of air pollution, the annual average concentrations of two components, fine particles matter (PM_2.5) and nitrogen dioxide (NO₂), were measured using a Danish air pollution modeling system. Road traffic noise levels within a three-kilometer radius of participants’ residential addresses were estimated using a validated model system called Nord2000 and measured in decibels (dB), the standard unit for the sound intensity.

Analysis of various pollutants and their effects on incident heart failure revealed:

• For each 5.1 µg / m³ increased exposure to fine particles over three years, the risk of incident heart failure increased by 17%;
• For each 8.6 µg / m³ NO increase₂ exposure over three years, the risk of incident heart failure increased by 10%;
• For every 9.3 dB increase in exposure to road traffic noise over three years, the risk of incident heart failure increased by 12%; and,
• Increased exposure to fine particles and former smoker status were associated with a 72% increased risk of incident heart failure.

“We were surprised at how two environmental factors – air pollution and road traffic noise – interacted,” Lim said. “Air pollution was a more important factor in the incidence of heart failure than traffic noise; however, women exposed to both high levels of air pollution and traffic noise showed the greatest increased risk of heart failure. In addition, approximately 12% of the total number of study participants had hypertension at the time of enrollment in the study. However, 30% of nurses with an incidence of heart failure had a history of hypertension, and they were the population most susceptible to exposure to air pollution. “

The study has several limitations. The researchers did not have information on other variables that may have affected the results of the analysis, such as measures of individual exposure to indoor air pollution or occupational noise; time spent outdoors; glass thickness of their home windows, which can influence noise pollution levels; if they had a hearing impairment; or individual socio-economic status. In addition, almost a quarter of the initial participants in the Danish nursing cohort were excluded from the final analysis because information was missing at the start or end of the study, so selection bias may be a contributing factor. The researchers also note that, since they studied the exposure levels and health effects of Danish nurses, a generalization of the results to men or other populations warrants caution.

Previous research has shown an association between air pollution and cardiovascular disease, and the American Heart Association detailed a collection of research on pollution risks in a science statement in 2004, with additional updated results. added in 2010. In 2020, the American Heart Association American Heart Association released a scientific statement and policy guidance to address the implications of air pollution amid the COVID-19 pandemic and beyond. The policy statement discusses policy directions at the local, state and federal levels to improve the health of our communities. Short-term exposure to high levels of certain air pollutants has also been linked to heart failure.