There is a growing body of research that suggests a link between particulate matter (PM) 2.5 exposure and an increased risk of stroke. PM 2.5 is a type of air pollution that is composed of very small particles, less than 2.5 micrometers in diameter. These particles can penetrate deep into the lungs, and exposure to them has been linked to a variety of health problems, including increase the risk of cardiovascular disease and stroke.
A recent study published in the journal Stroke found that exposure to PM 2.5 was associated with a significantly increased risk of stroke, even at levels below the current national air quality standards. The study included data on more than 3.2 million people living in California between 2000 and 2010. The researchers found that for every increase of 5 micrograms per cubic meter of PM 2.5 exposure, the risk of stroke increased by 8%.
Another study, published in the American Heart Association (AHA), found long-term exposures
(eg, ≥1 year) posed an even greater risk to cardiovascular mortality than short-term exposures.
the studies of long-term PM2.5 exposure and risk of ischemic heart disease (IHD) and stroke events, including incident of acute myocardial infarction (AMI), recurrent AMI, IHD mortality, incident of stroke, recurrent stroke, and cerebrovascular mortality via meta-analyses.
This study reviewed 69 published articles examining the effect of long-term PM2.5 exposure on risks of IHD and stroke events. The study found that a 10-μg/m3 increase in long-term average PM2.5 exposure was associated with a 23% increased risk of IHD mortality, a 24% increased risk of cerebrovascular mortality, and a 13% increased risk of incident stroke.
The link between PM 2.5 exposure and stroke is still being studied, oxidative stress and inflammation are key mechanisms by which PM2.5 acts to increase risk of CVDs.
- exposure to particulate air pollution activates of reactive oxygen species can affect vascular inflammation, atherosclerosis, basal vasomotor balance, coagulation and thrombosis, and platelet activation.
- Inflammatory cytokines are activated in response to air pollution exposures.
- Inhibited vascular repair after PM2.5 exposure via depletion of circulating endothelial progenitor cells.
- air pollution is altered autonomic nervous system balance which changes in heart rate variability.
People who are most at risk of exposure to PM2.5 include those who live in areas with high levels of air pollution, those who work outdoors, and those who have cardiovascular disease or other health conditions that make them more sensitive to air pollution. There are several things that people can do to protect themselves from exposure to PM2.5, including:
- Limiting time spent outdoors when air pollution levels are high
- Using a face mask when outdoors
- Avoiding high-traffic areas
- Keeping windows and doors closed when air pollution levels are high
- Installing an air purifier in your home
- Eating a healthy diet that is low in processed foods and saturated fat.
Compiled by Sirinat Puengcharoen, M.D., Neurologist.
- Stacey E. Alexeeff , PhD; Noelle S. Liao, MPH ; Xi Liu, MPH; Stephen K. Van Den Eeden , PhD; Stephen Sidney , MD, MPHReview of Long-Term PM2.5 Exposure and CVD Events J Am Heart Assoc. 2021;10:e016890. DOI: 10.1161/JAHA.120.016890
- The Harvard Six Cities Study: This study found that exposure to PM2.5 was associated with an increased risk of heart attack, stroke, and other cardiovascular diseases.
- The Intermountain West Study: This study found that exposure to PM2.5 was associated with an increased risk of death from cardiovascular disease.
- The Beijing Heart Study: This study found that exposure to PM2.5 was associated with an increased risk of stroke.
- The California Air Pollution Study: This study found that exposure to PM2.5 was associated with an increased risk of death from cardiovascular disease and stroke.