Air pollution has long been linked to a higher risk of stroke. A recent study examines the effect of air pollution on the stroke trajectory, including cardiovascular events following the first stroke and death.
The study was published on September 28th, 2022, in the medical journal of the American Academy of Neurology’s Neurology.
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We found that high levels of air pollution were associated with increased risks of transitions from being healthy to a first stroke, cardiovascular events after stroke and death, but with a stronger effect on the transition from being healthy to having a stroke.
Hualiang Lin PhD, Study Author, School of Public Health, Sun Yat-sen University
Hualiang Lin adds, “These results indicate that understanding and reducing the effects of air pollutants on different transition stages in stroke will be beneficial in managing people’s health and preventing the occurrence and progression of stroke.”
The investigation included 318,752 adults with an average age of 56 from the UK biobank database. At the commencement of the trial, none of the patients had a history of stroke or heart disease. The authors investigated people’s exposure to air pollution based on where they resided at the beginning of the study. The subjects were tracked for an average of 12 years.
There were 5,967 strokes throughout the period. Of those, 2,985 had cardiovascular disease, and 1,020 passed away.
Individuals exposed to high levels of air pollution were more susceptible to experiencing a first stroke, post-stroke cardiovascular disease, or mortality.
After taking into account other variables like smoking and physical activity level, scientists discovered that for every 5 micrograms per cubic meter (µg/m3) increase in fine particulate matter, for instance, the likelihood of transitioning from being healthy to experiencing a first stroke increased by 24% and the risk of transitioning from being healthy to dying increased by 30%.
Particulate matter is made up of liquids or solids that are suspended in the air. PM2.5, or fine particulate matter, has a diameter of less than 2.5 microns and contains fly ash from burning coal. Individuals who suffered a stroke during the research had an average PM2.5 exposure of 10.03 µg/m3, compared to 9.97 µg/m3 for those who did not.
In addition, the scientists discovered that the pollutants nitrogen oxide and nitrogen dioxide were linked to a greater risk of stroke and mortality.
More research is needed, but it’s possible that decreasing exposure to heavy levels of air pollution could play a role in reducing the progression of stroke. People can reduce their exposure by staying indoors on heavy pollution days, reducing their outdoor exercise, wearing masks to filter out particulate matter and using air purifiers.
Hualiang Lin PhD, Study Author, School of Public Health, Sun Yat-sen University
Lin pointed out that the findings do not establish that air pollution triggers stroke, cardiovascular disease, or mortality; rather, it indicates a connection.
One limitation of the research was that air pollution exposure was only assessed at the start of the study and only based on where people lived.
Journal Reference:
Fei Tian, et al. (2022). Air Pollution Associated With Incident Stroke, Poststroke Cardiovascular Events, and Death: A Trajectory Analysis of a Prospective Cohort. Neurology. doi: https://doi.org/10.1212/WNL.0000000000201316