Air Pollutants linked to risk of cardiac arrest: Study finds
Air pollutants have been found to increase the risk of cardiac arrest by an Italian study. The study research found that short-term exposure to air pollutants such as carbon monoxide, sulfur dioxide, and benzene raised the risk of cardiac arrest outside the hospital.
Air pollution has been proved as a possible trigger for out-of-hospital cardiac arrest3 but the relationship with specific air pollutants remains controversial because of the number of mechanisms involved. This study examined the associations between short-term exposure to particulate and gaseous pollutants and the incidence of out-of-hospital cardiac arrest.
“In addition to being a threat to the ecosystem, evidence is accumulating that dirty air should be considered a modifiable factor that contributes to cardiovascular disease,” the paper’s first author, Francesca Romana Gentile of the University of Pavia Fondazione and the IRCCS Policlinico San Matteo, said in a press statement.
Gentile and her colleagues described the relationship between out-of-hospital cardiac arrest and air pollution as “controversial.” Different studies have reached conflicting conclusions about the role of ozone.
Due to this quandary, the researchers set out to clarify whether and how air pollution impacts the risk of cardiac arrest outside the hospital.
The researchers focused on people living in the southern half of Italy’s Lombardy region. They analyzed 1,582 out-of-hospital cardiac arrest incidents that occurred during 2019.
After finding that cardiac arrest happened outside the hospital at a median daily rate of 0.3 cases per 100,000 inhabitants, they divided days into low and high. Low out-of-hospital cardiac arrest days had rates below the median daily rate, while high incidence days had rates above that median value.
To gauge air pollution, they used information from Italy’s environmental protection agency. In addition to benzene, carbon monoxide, and sulfur dioxide, the scientists looked into levels of fine particulate matter, nitrogen dioxide, and ozone.
The team found that most pollutants were present at higher levels on higher incidence days. Ozone, however, exhibited the opposite trend, with greater ozone levels being linked to lower rates of out-of-hospital cardiac arrest.
But after correcting for temperature, relative humidity, and day-to-day changes in pollutant concentrations, they found that every pollutant they tested, including ozone, raised the risk of out-of-hospital cardiac arrest. Sulfur dioxide had the strongest impact.
“We studied seven common pollutants and found that as the concentration of each rose, the risk of cardiac arrest increased,” Gentile said.
The research said, “confirmed that meteorological factors have to be taken into account when speaking about air pollution,” as cardiac arrest outside the hospital was more frequent during winter, when temperatures are colder.”
The pollutants they studied were also present at higher levels in colder weather as a result of home heating and transportation, among other factors.
Gentile hopes her team’s results can translate to better health care.
“The observed relationships between concentrations of individual pollutants and the likelihood of cardiac arrest could be used in future to predict the incidence of this life-threatening condition in specific geographical areas,” Gentile said. “We hope that air pollutant monitoring can improve health service efficiency by being factored into ambulance forecasting models and warning systems.”