Long-term exposure to air pollution has been associated with an increased risk of arrhythmia, or irregular heartbeat, according to a large study conducted in 322 Chinese cities. The study evaluated hourly exposure to air pollution and the sudden onset of arrhythmia symptoms using data from 2025 hospitals.
The research, led by Renjie Chen from Fudan University in Shanghai, found that acute exposure to ambient air pollution was linked to an increased risk of symptomatic arrhythmia. The common arrhythmia conditions atrial fibrillation and atrial flutter, which can lead to more severe heart disease, affect an estimated 59.7 million people globally.
Air pollution is a modifiable risk factor for heart disease, but the evidence linking it with arrhythmia has been inconsistent. The new findings, which were published in the European Heart Journal, provide further evidence that reducing air pollution could help to prevent heart disease.
Air pollution has become a growing concern globally, with increasing evidence linking it to a range of health problems. The World Health Organization estimates that air pollution causes seven million premature deaths each year.
The study highlights the need for policymakers to take action to reduce air pollution levels, particularly in densely populated areas. Measures such as promoting public transportation, reducing emissions from factories and vehicles, and increasing the use of clean energy sources could all help to improve air quality and prevent heart disease.
The researchers note that further studies are needed to confirm their findings and to explore the mechanisms by which air pollution may affect the heart. However, the new research adds to the growing body of evidence suggesting that reducing air pollution could be an important way to improve public health and reduce the burden of heart disease.
"The risks occurred during the first several hours after exposure and could persist for 24 hours. The exposureresponse relationships between six pollutants and four subtypes of arrhythmias were approximately linear without discernable thresholds of concentrations," Chen said.
The study included 1,90,115 (over 1.9 lakh) patients with acute onset of symptomatic arrythmia, including atrial fibrillation, atrial flutter, premature beats and supraventricular tachycardia.
Exposure to ambient air pollution was most strongly associated with atrial flutter and supraventricular tachycardia, followed by atrial fibrillation and premature beats, the researchers said.
Among six pollutants, nitrogen dioxide (NO2) had the strongest association with all four types of arrythmias, and the greater the exposure, the stronger the association, they said.
"Although the exact mechanisms are not yet fully understood, the association between air pollution and acute onset of arrhythmia that we observed is biologically plausible," the authors said.
"Some evidence has indicated that air pollution alters cardiac electrophysiological activities by inducing oxidative stress and systemic inflammation, affecting multiple membrane channels, as well as impairing autonomic nervous function," they added.
The researchers noted that the association was immediate and underscores the need to protect at-risk people during heavy air pollution.
(With inputs from PTI)