New York, Sep 17 (IANS): People with one of the most common heart disorders or atrial fibrillation (AFib) 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, say researchers.

For the study, published in the journal JAMA Network Open, the research team followed more than 31,000 people living in Allegheny County since 2007 with atrial fibrillation.

"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 study author Jared W Magnani, from the University of Pittsburgh in the US.

"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 added.

Using suitcase-sized air pollution monitors mounted on telephone poles, the team was able to measure the exact levels of fine particulate pollution.

The researchers found that stroke risk steadily increased with higher daily exposure to air pollution.

People with AFib are already at five times the risk of stroke, so the additional risk posed by fine particulate pollution is particularly concerning, the study noted.

"Our results advance the understanding of how air pollution impacts public health and strengthens the argument for continued advocacy to curb pollution," Magnani said.

"Fine particulate pollution is very small -- it is able to get into our bodies through our lungs and into our bloodstream where it can trigger heart events," he added.

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 line versus above.

"Our study indicates the importance of modifying pollution as a risk factor for adverse health outcomes," the study authors wrote.

The researchers noted that 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 AFib.