A higher risk of stroke has frequently been linked to air pollution. In a recent study, the impact of air pollution on the progression of stroke—including cardiovascular complications after the initial stroke and mortality—was examined. The research was published online in Neurology®, the medical journal of the American Academy of Neurology, on September 28, 2022.
Hualiang Lin, PhD, of the Sun Yat-sen University School of Public Health in Guangzhou, China, is the study’s lead author. “We found that high levels of air pollution were associated with increased risks of transitions from being healthy to having a first stroke, cardiovascular events after stroke, and death, with a stronger effect on the transition from being healthy to having a stroke,” she said. “These results show that understanding and reducing the effects of air pollution on the different stages of stroke progression will help people’s health and prevent strokes from happening or getting worse.
The study included 318,752 participants from the UK Biobank database, with an average age of 56.At the beginning of the study, none of the participants had a history of heart disease or a stroke. Based on participants’ residences at the start of the study, researchers examined participants’ exposure to air pollution. The participants lasted an average of 12 years.
A stroke occurred in 5,967 people during that time. 2,985 of them went on to develop cardiovascular diseases, and 1,020 of them passed away.
People who were exposed to high levels of air pollution had a higher risk of dying, having their first stroke, or developing cardiovascular disease after having one.
Researchers discovered that for each increase in fine particulate matter of 5 micrograms per cubic meter (g/m3), for instance, the risk of going from being healthy to having a first stroke increased by 24% and the risk of going from being healthy to dying increased by 30% after adjusting for other factors that could play a role, such as smoking and level of physical activity. Particulate matter is made up of liquids or solids suspended in the air. Fly ash from the combustion of coal is included in fine particulate matter, or PM2.5, which has a diameter of less than 2.5 microns. Those who experienced a stroke during the course of the study experienced an average PM2.5 exposure of 10.03 g/m3, as opposed to 9.97 g/m3 for those who did not.
The researchers also discovered a link between the pollutants nitrogen dioxide and oxide and an increased risk of stroke and death.
According to Lin, decreased exposure to high levels of air pollution may help slow the progression of stroke. However, more research is required. Staying inside on days with high pollution, limiting outdoor activity, donning masks to filter out particulates, and using air purifiers are all ways that people can lessen their exposure.
Lin says that the results only show a link between air pollution and stroke, heart disease, or death. They do not prove that air pollution causes stroke, heart disease, or death.
A weakness of the study was that air pollution exposure was only looked at at the beginning and was only based on where the participants lived.
