Europe’s Air Pollution–Related CVD Deaths 4x Those of US

LONDON — Cardiovascular disease (CVD)–related deaths in Europe due to air pollution far exceeded those in the United States, according to experts at the European Society of Cardiology (ESC) Congress 2024.

“Europe is so far behind, with almost four times the level of deaths due to cardiovascular disease as compared to North America,” said Thomas Münzel, recently retired cardiologist from the University Medical Center Mainz, Mainz, Germany, speaking to Medscape Medical News after presenting at a session on environmental health concerns, in particular on noise and air pollution, for cardiologists.

Münzel and his colleagues from the Atmospheric Chemistry Department, Max Planck Institute, Mainz, Germany, generated a global heat map showing estimated global excess mortality with cardiovascular causes attributable to air pollution. Published online in 2023, it showed data from Europe that surprised the experts.

As expected, Asia is a major contributor to global deaths from air pollution with excess CVD-related deaths at 3.06 million. “What surprised us most and is very worrying is that Europe has the second highest mortality from CVD attributable to air pollution, with nearly half a million cardiovascular deaths per year [484,000],” said Andreas Daiber, professor of molecular cardiology also based at the University Medical Center Mainz. 

By comparison, North America has about one quarter of the European total, at 135,000 excess CVD deaths. “You would not expect this figure in North America when you look at the population there, which is not very dissimilar to Europe,” said Daiber. 

The differences in figures between the various regions are largely due to variations in the legal limits for particulate matter with a diameter of 2.5 µm (PM_2.5), the researchers explained.

“It’s a political matter, and air pollution is not something that doctors and patients can influence directly,” Münzel said. However, he added, “as the cardiovascular community, we should be inviting atmospheric chemists and environmental health scientists onto our guidelines committees and change the legal limits for exposure to particulate matter with a diameter of 2.5 µm or less, which is the leading cause of air pollution–related cardiovascular disease.”

The World Health Organization (WHO) recommends that the annual average concentration of PM_2.5 should not exceed 5 µg/m³. The legal annual limit is 12 µg/m³ (aiming for 9 µg/m³ by 2032) in North America, 8 µg/m³ in Australia, 10 µg/m³ in Canada, and 25 µg/m³ (aiming for 10 µg/m³ by 2030) in Europe.

“Australia and Canada are doing so much better than Europe,” said Daiber, adding that “the population density also has an important impact, and this is lower in the United States, Canada, and Australia.”

Daiber pointed out that there is also a growing concern around unregulated ultrafine particles (UFPs). “More worrisome still is recent mechanistic and health impact insight into air pollution showing that the smaller particles, the nano-sized UFPs, carry the highest potential to cause CVD and deaths…So far UFP-exposure concentrations are completely unregulated.”

We’re All at Risk

It’s not only people with existing CVD who are at a risk for pollution-related death.

High concentrations of air pollutants can stimulate the atherosclerotic process, leading to the buildup of plaques over many years. 

Diabetes and arterial hypertension — risk factors for CVD — can also be attributed to air pollution and can manifest by living in an area of high air pollution.

“It’s clear that two thirds of all chronic disease is triggered by environment stressors and is not due to genetic predisposition, as clearly shown in twin studies. Around 65% of these are cardiometabolic in nature,” stressed Daiber.

Noise Pollution Impact on CVD: Often Forgotten but Important

Münzel also spoke about the impact of noise pollution on CVD. He highlighted epidemiologic studies that show a close association between transportation noise and cardiometabolic diseases: Ischemic heart disease, heart failure, arrhythmia, stroke, diabetes, and obesity. Experimental studies also show noise exposure causes high blood pressure, neurohormonal activation, and oxidative stress. “In particular, nighttime noise is more damaging,” he noted. “Traffic noise is highly connected to air pollution (PM_2.5), probably leading to additive health effect.”

From a practice perspective, cardiologists should ask some patients about their living arrangements. “If managing a patient who has chest pains, I often ask them if they are exposed to noise and to air pollution, or if their bedroom is directly onto the street or to a garden, and whether they sleep with the window open or closed, bearing in mind noise and high PM_2.5 levels,” Münzel explained. 

Mechanistically, NOX2 (the phagocytic isoforms of this important source of oxidative stress) knockout prevents CVD damage, indicating the central role played by immune cells that become activated by noise to infiltrate cardiovascular tissues, causing damage by detrimental chronic inflammation and oxidative stress, Münzel explained. 

He added that animal studies have shown that activating endothelial AMP kinase pharmacologically or via physical exercise and intermittent fasting can mitigate the negative impacts of noise, providing a rationale for lifestyle changes that everyone can do.

He concluded, saying, “We have to communicate the importance and significant impact of including environmental noise as a cardiovascular risk factor in clinical guidelines.”

Session co-moderator and clinician scientist Franz Weidinger of Landstrasse Clinic, Vienna, Austria, commented saying, “The talks really summarized the multiple pieces of evidence on the detrimental effects of various environmental health factors, including air and noise pollution and climate change.”

“We did see evidence on surrogate parameters, but there is no proof of a causal relationship between air pollution and clinical outcomes. But, as said, we cannot expect many randomized trials in this area. So I think, with the evidence we have, it is enough for us to call on policymakers and scientists to take action and mitigate the risk.”

Reflecting the calls from Münzel and Daiber, Weidinger also called for collaboration. “We really need to team up with the WHO and the World Heart Federation to spread the message globally. It’s a message for the entire world.”

Daiber, Münzel, and Weidinger had no financial disclosures.