PM2.5 in air pollution linked to sudden cardiac arrest

Credit: Benjamín Gremler/Unsplash.

PM2.5 category of particulate matter in the air is known to strongly increase the risk of cardiovascular, respiratory, and even ocular diseases.

In a study from Duke-NUS Medical School, scientists found that these small particles in air pollution might have caused sudden cardiac arrests in some people who were not in hospital but simply going about their normal lives.

The study team examined whether there was a correlation between out-of-hospital cardiac arrests (OHCA) and the levels of tiny air pollution particles that are at least 25 times smaller than the width of a human hair.

The team found 492 out of 18,131 OHCA events that the researchers were able to attribute to an increase in PM2.5 concentrations either on the day of the cardiac arrest or up to two days before.

The study also found a clear reduction in risk from three to five days after exposure to the pollutant, suggesting a relatively short-term effect.

The average PM2.5 concentration during the study period was 18.44 micrograms per cubic meter, and a decrease of just one microgram resulted in an 8% reduction in the number of OHCA events, while a decrease of three micrograms brought a 30% reduction.

The team says these results make it clear that efforts to reduce the levels of air pollution particles in the 2.5 micrograms or lower range, and steps to protect against exposure to these particles, could play a part in reducing sudden cardiac arrests in Singapore’s population.

They emphasize the relevance of this research to many cities around the world where air pollution is an everyday problem.

Less common but extreme events, such as haze and wildfires, can also lead to sudden and dramatic increases in PM2.5 particles.

Despite the consistency in study findings with those elsewhere and a biologically plausible mechanism of the effect of PM2.5 on OHCA events, the team cautions that this was an observational study and does not imply direct causation.

If you care about heart health, please read studies that eating whole eggs bad for your heart, and Flu and COVID-19 vaccines may increase heart disease risk.

For more information about heart health, please see recent studies about artificial sweeteners linked to a higher risk of heart disease, and results showing which is bad for your heart health: Coconut oil, olive oil, or butter?

The study was conducted by Joel Aik et al and published in The Lancet Public Health.

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