Air pollution linked to dangerous heart conditions in major study

·3-min read
Air pollution linked to dangerous heart conditions in major study

Exposure to air pollution has been linked to an increased risk of irregular heartbeat, in a large study of 322 Chinese cities.

Two common irregular heartbeat conditions - known as arrhythmia - are atrial fibrillation and atrial flutter, both of which can progress to more serious heart disease. They affect an estimated 59.7 million people around the world.

Evidence linking air pollution with arrhythmia has been inconsistent, but a new study published in CMAJ (Canadian Medical Association Journal) has found there is an association between air pollution and increased risk of the conditions.

To find this link, Chinese researchers evaluated hourly exposure to air pollution and the sudden onset of symptoms of arrhythmia using data from 2,025 hospitals in 322 Chinese cities.

Air pollution in China is well above the World Health Organization's (WHO) guidelines for air quality, and the researchers conducted their analysis using air pollutant concentrations from monitoring stations closest to the reporting hospitals.

"We found that acute exposure to ambient air pollution was associated with increased risk of symptomatic arrhythmia," said Dr Renjie Chen, of Fudan University’s School of Public Health in Shanghai.

"The risks occurred during the first several hours after exposure and could persist for 24 hours".

The study included 190,115 patients with acute onset of symptomatic arrhythmia, including atrial fibrillation, atrial flutter, premature beat, and supraventricular tachycardia - a heart condition which causes abnormally fast heart rate.

Air pollution was most strongly linked to atrial flutter and supraventricular tachycardia, followed by atrial fibrillation and premature beats. Among six pollutants, nitrogen dioxide (NO2) had the strongest association with all four types of arrhythmias. The greater the exposure, the stronger the association.

"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 wrote.

"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".

The authors noted that the association was immediate and underscored the need to protect at-risk people during heavy air pollution.

"Our study adds to evidence of adverse cardiovascular effects of air pollution, highlighting the importance of further reducing exposure to air pollution and of prompt protection of susceptible populations worldwide," they concluded.

Air pollution kills 1,200 children each year in Europe

Serious issues with air pollution are also apparent in Europe.

The European Environment Agency (EEA) last month warned air pollution kills more than 1,200 children and teenagers each year in Europe

In a report, it also warned that it can significantly increase the risk of disease later in life.

Despite improvements made in recent years, the level of key air pollutants in many European countries remain “stubbornly above” WHO guidelines, the report warned.

Younger people are particularly susceptible to air pollution because their bodies and immune systems are still developing.

The report estimated that air pollution causes more than 1,200 premature deaths each year among the under 18s across the EEA’s member countries, which don’t include the UK or Switzerland.