Study Links Risk of Stroke to Air Pollution Exposure

New research highlights the potential stroke risk linked to air pollution exposure, even for a short period of time, indicating that areas with higher levels of pollution may increase the risk of hospitalization due to a stroke. 

In a study published last week in the medical journal BMJ, formerly known as the British Medical Journal, researchers from Edinburgh University determined pollution of all different types was directly associated with an increased risk of stroke. The higher the level of pollution, the more strokes people experienced.

Increased levels of pollution from nitrogen dioxide, sulfur dioxide, carbon monoxide and particulate matter were associated with increases in strokes and hospital admissions.

The strongest associations were most detectable on the day of exposure and with particulate matter of 2.5 parts per million (ppm), finer particles compared to coarse particles. However increases in particulate matter had longer lasting effects.

Researchers did a meta-analysis of reviewing nearly 3,000 observational studies from 28 different. More than 200 studies were reviewed in-depth and 100 of those met the criteria to be included in the analysis. A total of 6.2 million events were reviewed overall.

The study linked admission to the hospital for stroke or death from stroke, as being associated with an increase in concentrations of carbon monoxide, sulfur dioxide and nitrogen dioxide. The weakest association was linked to ozone.

The reasons for the association were unclear, and the study did not determine a cause and effect. More so, it revealed people were more likely to have strokes in the immediate aftermath of episodes of raised air pollution.

Researchers said, the air pollution can constrict blood vessels, increase blood pressure, and increase the risk for clots. A study published late last year also suggested that air pollution increased a person’s risk of developing heart disease. Researchers of the study called it an avoidable heart risk factor.

Strokes kill approximately 5 million people each year worldwide. Typically, conditions and habits such as obesity, smoking and high blood pressure are considered primary risk factors.

Another study published last year linked exposure to air pollution in children to changes in the brain and an increased risk of the development of autism, schizophrenia and other neurological disorders.

Other research has linked air pollution to a higher risk of heart attacks, stroke and other illnesses. However, once air pollution spikes, there is little a person can do to protect themselves from the harmful effects.

Air pollution accounts for 3.1% of global disability adjusted life years and more than 3 million deaths worldwide were attributed to ambient air pollution in 2010.

Research published in the American Journal of Public Health indicates minority families may be more likely to live in the path of harmful air pollution than white families. Data indicates energy manufacturers pollute in or around minority communities, leaving many to conclude the government is less likely to advocate for the communities.

Concerns over the intentional decision by some companies to pollute over minority communities has led to environmental justice lawsuits in recent years.

Authors of the latest study are calling for policies to be implemented to reduce air pollution and lead to cleaner air. This can have a substantial impact on a person’s risk and reduce the burden of stroke.