Air pollution exposure multiplies risk of stroke in AF patients

Jared Magnani

Sufferers of atrial fibrillation (AF) who are exposed to greater levels of pollution have a 1.2-fold higher risk of stroke than their peers who live with less pollution, according to a JAMA Network Open study.

The study carried out by researchers at the UPMC Heart and Vascular Institute and University of Pittsburgh School of Medicine, Pittsburgh, USA is the largest of its kind to include neighbourhood-specific pollution data—rather than simply hospitalisation data—according to the study team.

“We measured pollution exposure at people’s doorsteps by using geocoding and then determined their annual exposure to particulate matter. This approach and the sample size make our study particularly powerful,” said Jared W Magnani, UPMC cardiologist and associate professor of medicine. “We can use this information to guide our patients by advising them to limit exposure to pollution. For example, we can notify those with atrial fibrillation to avoid being outside on days with unhealthy air quality, which may reduce their risk of stroke.”

Magnani and his colleagues followed more than 31,000 people living in Allegheny County since 2007 with AF. Using air pollution monitors mounted on telephone poles, the team measured levels of fine particulate pollution (PM2.5) that the participants were breathing on a daily basis.

The researchers found that stroke risk steadily increased with higher daily exposure to air pollution. People with AF already are at increased risk of stroke, Magnani noted.

“Our results advance the understanding of how air pollution impacts public health and strengthens the argument for continued advocacy to curb pollution,” he said. “Fine particulate pollution is very small—it is able to get into our bodies through our lungs and into our blood stream where it can trigger heart events.”

The team went on to examine the impact of pollution on different demographic and socioeconomic groups. They found that fine particulate exposure is 1.5-fold higher in blacks compared to whites, and 1.3-fold higher in those living below poverty versus above.

“Pollution exposure correlates with socioeconomic position, as people living closer to industrial sources tend to be lower income and minoritised. Hence, air pollution worsens racial disparities in health outcomes, due to the increased residential exposure,” Magnani said. “Our study indicates the importance of modifying pollution as a risk factor for adverse health outcomes.”

Magnani said future research will explore how individual factors—such as physical activity, diet, health care access and medication—might interact with pollution levels to modify stroke risk for people with AF.


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