Short-term Exposure To Polluted Air Raises Stroke Risk, Says Research

A long weekend break in a big city could trigger a stroke, suggests a new study.

Researchers found that being exposed to polluted air for just a few days can increase the risk by up to 60 percent.

Jordanian scientists collated data from more than 18 million cases of stroke to explore the risk of people suffering strokes within five days of being exposed to polluted air.

They found higher concentrations of nitrogen dioxide, carbon monoxide and sulfur dioxide, as well as different sizes of particulate matter, to lead to an increased risk of stroke.

The authors of the study, published in the journal Neurology, also saw that the risk of dying as a result of a stroke also rose with higher levels of pollution.

The scientists ominously warned that their results reinforced the importance of global efforts to reduce pollution.

The researchers, from the University of Jordan in the country’s capital city of Amman, reviewed 110 studies involving a collective figure of more than 18 million strokes from mainly high-income countries.

They focused on pollutants such as nitrogen dioxide – formed when fossil fuels such as coal, oil, methane gas or diesel are burned at high temperatures – ozone gas emitted as a result of UV light and electrical discharges within the Earth’s atmosphere; carbon monoxide which mainly derives from burning material containing carbon compounds and sulfur dioxide, again formed when sulfur-containing fuel such as coal, petroleum oil, or diesel is burned.

The scientists found that the risk of death from stroke also rose alongside higher pollution levels.

Higher concentrations of nitrogen dioxide were linked to a 33 percent increased risk of death from stroke, whilst higher levels of sulfur dioxide saw a massive 60 percent increase in death risk.

The study team also looked at different sizes of particulate matter, including PM1 (air pollution less than one micron in diameter), and larger matter, such as PM2.5 and PM10.

Particles PM2.5 and smaller include inhalable particles from motor exhaust, fuel burning by power plants and other industries, and forest and grass fires, whilst larger PM10 particles comprise dust from roads and construction sites.

The researchers found that those exposed to higher concentrations of air pollution had an increased risk of stroke.

Higher concentrations of nitrogen dioxide were linked to a 28 percent increased risk of stroke; higher ozone levels were linked to a 5 percent increase; carbon monoxide had a 26 percent increase and sulfur dioxide had a 15 percent increase.

A higher concentration of PM1 was also linked to a nine percent increased risk of stroke, with PM2.5 at 15 percent and PM10 at 14 percent.

Higher concentrations of PM2.5 saw a nine percent increase in death by stroke, and PM10 a two percent increase.

Study author Dr. Ahmad Toubasi, a medical researcher at the University of Jordan, said his team’s research proved how deadly pollution is, and how important it is that we aim to reduce it across the globe.

“Previous research has established a connection between long-term exposure to air pollution and an increased risk of stroke,” Dr. Toubasi said.

“However, the correlation between short-term exposure to air pollution and stroke had been less clear.

“For our study, instead of looking at weeks or months of exposure, we looked at just five days and found a link between short-term exposure to air pollution and an increased risk of stroke.

“There is a strong and significant association between air pollution and the occurrence of stroke as well as death from stroke within five days of exposure.

“This highlights the importance of global efforts to create policies that reduce air pollution.

“Doing so may reduce the number of strokes and their consequences.”

Dr. Toubasi and his team did admit, however, to their study being limited by their meta-analysis mostly comprising of studies conducted in high-income countries, whilst limited data was available from low and middle-income countries that may be exposed to worse pollution.

Produced in association with SWNS Talker