Stroke is the second most prevalent cause of mortality and a major cause of disability worldwide. There is mounting evidence that air pollution increased the risk of stroke. Air pollution levels have been steadily rising over the past few decades, and it is currently thought that 14% of all deaths from stroke are related to air pollution.
It is challenging to interpret prior literature since stroke was frequently not differentiated by cause, ischaemic, or hemorrhagic. People with cardiovascular disease and stroke brought on by major artery disease or small vessel disease will experience this effect the most strongly.
A man in stripes wearing facemask in a city with polluted air
Strokes and air pollution have previously been connected. The goal of Hualiang Lin and his team at Sun Yat-sen University in China was to comprehend the risk among those who had never had a stroke. Additionally, they were curious about how air pollution would affect any post-stroke consequences like cardiovascular disease.
More than 318,000 residents of the UK had their exposure to air pollution evaluated by the researchers. This was based on air pollution testing done between January 2010 and 2011 within 100 square meters of the participants' residences by independent researchers.
The individuals, who ranged in age from 40 to 69 at the outset of the study, were a part of the UK Biobank investigation. They had no history of ischemic heart disease, which are cardiovascular issue brought on by a constriction of the heart's arteries, cancer, or strokes or mini-strokes, which are described as brief interruptions in the blood flow to the brain.
Over an average 12-year follow-up period, the individuals experienced 5967 strokes, 2985 cases of cardiovascular disease, and 1020 total fatalities.
The researchers discovered that every increase in fine particulate matter (PM2.5) exposure of 5 micrograms per cubic meter (g/m3) over the course of a year among the participants was associated with a 24% increase in their risk of having a stroke after controlling for additional variables that can affect stroke risk, such as physical fitness levels.
PM2.5, which has a diameter of fewer than 2.5 micrometers, is mostly emitted via exhaust pipes. According to the World HealthOrganization, our yearly PM2.5 exposure shouldn't be higher than 5 g/m3.
The average annual PM2.5 exposure for study participants who experienced a stroke was 10.03 g/m3, compared to 9.97 g/m3 for individuals who did not.
The observational study is based on an examination of 318,752 UKBiobank participants' health records and many years' worth of air pollution data.
For 3,765,630 person-years of follow-up, the researchers monitored these people's health changes. 5,967 persons had their first or incident strokes during that time. Additionally, 2,985 people experienced post-stroke cardiovascular complications, and there were subsequently 1,020 fatalities.
In order to calculate exposure based on where people resided, the researchers also analyzed 1-year worth of air pollution data. Based on information about terrain, population, transportation, and land use, they modeled each person's exposure to contaminants.
According to the findings, those who suffered strokes during the trial had an average PM 2.5 exposure of 10.03 g/m3. The exposure for those who did not get a stroke was 9.97 g/m3.
In essence, this is another demonstration of the long-term harmful effects of pollution, and in particular of fine particles and nitrogen oxides, on [the] cardiovascular system. This new study tries to evaluate the ‘dynamic’ effects of pollution on stroke risk and mortality in a large population during a very long follow-up period.- Dr. Folino
In the US, websites like the federal government's AirNow offer an evaluation of the current regional air quality. If you have an iPhone, the Weather app can allow you to view a broad evaluation of the air quality in your neighborhood.
The authors of the study advise people to limit their outside activities, including exercise, on days when the air quality reaches moderate to dangerous levels and to think about using masks and using HEPA air purifiers.
All people, but especially those with a high cardiovascular risk, should avoid exposure to high pollution levels. We have to carry out physical activities in healthy areas and pay attention to the possible polluting sources inside [the] home.- Dr. Folino
Dr. Iyer acknowledged that residents in densely populated urban regions may not always be able to avoid air pollution.
Take care of your health in other ways to make sure that you have strong lungs by exercising, staying physically fit, having a good diet, and not smoking. Those are all things to mitigate and offset the exposure to particulate matter, air pollution.- Dr. Adi Iyer, neurosurgeon
The current understanding of air pollution increased the risk of stroke is based on observational big-data studies, which are typically restricted to specific geographic regions, lack adequate clinical information, and produce, at best, ambiguous results.
Future studies ought to concentrate on reducing this possible exposure misclassification. Wearable sensors have been available in recent years.
These sensors track individual exposure and have the ability to account for variations in metabolic activity by, among other things, tracking breathing rate and step count. The use of these portable sensors to pinpoint patient populations most at risk seems promising.