Study shows link between air pollution, stress and heart health risk

Study shows link between air pollution, stress and heart health risk

A study of more than 3,000 U.S. counties with 315 million residents found that air pollution is linked to stress and depression and increases the risk of death from cardiovascular disease in those under 65. The research will be presented today at ESC Preventive Cardiology 2024, a scientific congress of the European Society of Cardiology (ESC).

Our study shows that the air we breathe affects our mental wellbeing, which in turn impacts heart health.”

Dr. Shady Abohashem, lead author of the study Harvard Medical School, Boston, USA

According to the World Health Organization, air pollution caused an estimated 4.2 million premature deaths worldwide in 2019. Mental illness is also associated with premature death. This study examined whether air pollution and poor mental health are related and have a common influence on death from cardiovascular disease.

The study focused on particles smaller than 2.5 micrometers in diameter, also called fine particles or PM2.5. They come from vehicle exhaust, power plant combustion, and wood burning and pose the highest health risk. To conduct the study, data on annual county-level PM2.5 levels was obtained from the Centers for Disease Control and Prevention (CDC).4 PM2.5 exposure was classified as high or low according to World Health Organization (WHO) standards. Researchers collected data from the CDC on the average number of days (age-standardized) that county residents experienced mental health problems — including stress, depression and emotional problems. Each county was then divided into three groups based on these numbers. Counties in the top third reported the most poor mental health (PMH) days.4 Age-adjusted premature cardiovascular mortality rates (under age 65) per county were determined by the CDC. County characteristics were obtained from the County Health Rankings project.

The study covered 3,047 U.S. counties with 315,720,938 residents (with over 207 million ages 20 to 64 and 50% women) in 2013. Between 2013 and 2019, approximately 1,079,656 (0.34%) participants died from cardiovascular disease before age 65. Researchers analyzed the links between pollution, mental health and premature cardiovascular mortality after taking into account factors that could influence the links.

Counties with dirty air (high PM2.5 concentrations) were 10% more likely to report high PMH days than counties with clean air (low PM2.5 concentrations). This risk was significantly greater in counties with a high prevalence of minority groups or poverty. The association between PMH and premature cardiovascular mortality was strongest in counties with higher air pollution levels (above WHO recommended levels: ≥10 µm2). In these counties, higher PMH levels were associated with a threefold increase in premature cardiovascular mortality compared to lower PMH levels. Furthermore, one-third of the pollution-related risk of premature cardiovascular death was explained by increased PMH exposure.

Dr. Abohashem said: "Our results show a double threat from air pollution: not only does it worsen mental health, but it also significantly increases the risk of heart-related deaths, which are associated with poor mental health. Public health strategies are urgently needed to combat both when it comes to air quality." and mental wellness to maintain cardiovascular health.”

The pollution levels in the ESC countries can be viewed in the ESC Atlas of Cardiology:

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