Air pollution may increase stroke risk in AF
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Excess exposure to fine particulate matter measuring 2.5 µm or less may increase the risk for stroke in patients with atrial fibrillation, researchers found.
“The findings contribute to our understanding of an environmental exposure — pollution — and its hazardous effect on our patients’ health,” Jared W. Magnani, MD, MSc, associate professor of medicine at University of Pittsburgh School of Medicine, told Healio. “Our study confirms the intersection of multiple social determinants on health-related exposure; we saw racial differences in pollution exposure. We need more comprehensive programs to address social and environmental exposures in disadvantaged populations.”
Effects of pollution
In this cohort study published in JAMA Network Open, Zachary J. Rhinehart, MD, cardiologist at University of Pittsburgh, and colleagues analyzed data from 31,414 patients (mean age, 74 years; 50% women) with AF from a regional health care system in Pittsburgh.
“The results are particularly relevant to the region, as Pittsburgh is one of the 10 most polluted cities in the U.S.,” Magnani said in an interview. “The paper references the American Lung Association’s annual report.”
Researchers geocoded their addresses to determine annual estimates of particulate matter exposure on a residential level. This was also done to obtain neighborhood-level income and educational level.
The primary independent variable for this study was the annual mean exposure to fine particulate matter measuring 2.5 µm or less (PM2.5) at individual residential locations. Hospitalization for ischemic stroke was the primary outcome. The date of the stroke was considered the initial date of hospitalization. The time to event was defined as the start of observation, or the earliest identification of AF in the electronic health record, to the first stroke event during the study. Follow-up was conducted for a median of 3.5 years.
The mean annual PM2.5 exposure during the study was 10.6 µg/m3.
Each 1 standard deviation increase in PM2.5 was linked to an increased risk for stroke after adjusting for clinical and demographic variables (HR = 1.08; 95% CI, 1.03-1.14). This was also observed after full multivariable adjustment for educational level and household income (HR = 1.07; 95% CI, 1-1.14).
Compared with the lowest quartile of PM2.5 exposure, the highest quartile had an increased risk for stroke (HR = 1.36; 95% CI, 1.18-1.58). Although attenuated, this increased risk persisted after adjusting for clinical covariates, educational level and income (HR = 1.21; 95% CI, 1.01-1.45).
Advocating for public health
“A large literature informs us that social determinants and environmental factors contribute immensely to our patients’ health,” Magnani told Healio. “We need to advocate for public health to improve the welfare of our patients, particularly disadvantaged populations. We also need to educate our patients about their neighborhood and the environment, and how exposures such as pollution might increase their health risks. We need to make determination of social determinants like pollution exposure readily available to clinicians and teach them how to use this information to assist their patients.”
For more information:
Jared W. Magnani, MD, MSc, can be reached at magnanij@pitt.edu; Twitter: @jared_w_magnani.
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