Living next to a city park significantly reduces the risk of a stroke

On the other hand, it is better not to have your house next to a busy highway.

Stroke is still one of the leading causes of death in the Netherlands. About 30,000 people have a stroke every year, while around 120,000 people live with its consequences. It is known that exposure to air pollutants, such as particulate matter, can increase the risk of stroke. But researchers have now also discovered what can significantly reduce the chance, namely: living next to a piece of greenery.

Study

In the study the researchers studied the exposure to air pollutants of more than 3.5 million people living in Spain’s Catalonia. Very concretely, they analyzed the amount of nitrogen dioxide (NO2), particulate matter below 2.5 microns (PM2.5) and soot particles in the place of residence of the persons studied. These are all substances that can be associated with car traffic. It was also examined whether there was a park or green strip within a radius of 300 meters from the house. They then mapped out the consequences of this for health and, more specifically, for the risk of a stroke. “As the number of people who will suffer and die from stroke is predicted to increase in the coming years, it is important to understand all the risk factors involved,” said study researcher Carla Avellaneda.

Bandage

The findings are quite worrying. “We found a strong association between NO2 emissions and the risk of stroke,” Avellaneda told Scientias.nl† “Every 10 µg/m3 increase in NO2 in the air leads to a 4 percent increase in the risk of stroke.” The same happens when the PM2.5 content increases by 5 µg/m3. For soot particles, the risk increases by 5 percent for every 1 µg/m3 increase in the atmosphere. Why do these substances increase the risk of stroke? “Exposure to NO2, for example, can lead to systemic inflammation,” explains Avellaneda. “It can also cause an accelerated progression of atheromatosis (a complicated and slowly progressing disease in which fatty substances are deposited in the walls of arteries, ed.) and a predisposition to cardiac arrhythmias; three things that play an important role in the development of a stroke.”

city ​​park

At the same time, the findings show that living next to a city park significantly reduces the risk of a stroke. People who live next to green areas have a whopping 16 percent lower risk of stroke. It therefore seems very likely that more nature in the area is beneficial to health. “There is mounting evidence that green areas have health benefits,” Avellaneda says. “Both for your mental health, your well-being, the risk of cardiometabolic disease and even the risk of death – just to name a few. To date, however, available data on the impact of green spaces on stroke risk has been scarce. But our findings seem to confirm the protective effect of green areas.”

According to the researchers, the findings underscore the need to think about the level of air pollution that is considered safe. The World Health Organization has recently tightened its guidelines for air pollution. It means that air pollution levels have to be drastically reduced to prevent harmful health effects and death in humans. Since September 22, 2021, the WHO has recommended the following standards: 15 g/m PM10 and 5 μg/m³ PM2.5. That is half the EU standard. For many countries – including the Netherlands – such limit values ​​are still a long way off. For example, high particulate matter concentrations are still measured in many places in the Netherlands. And the nitrogen concentration also leaves a lot to be desired, especially in urban areas.

Safe Levels

What is alarming, however, is that the levels measured during the current study were on average lower than the values ​​set by the European authorities, but apparently still increase the risk of stroke. “This study shows that the risk of stroke is therefore present even at levels that meet European air quality standards,” Avellaneda said. This means that levels labeled safe may not be so safe after all. So the health impacts could potentially be even more serious where these ‘safe levels’ are exceeded.

Measures

The research team states that ‘daring measures’ are therefore needed to reduce car use in particular. “It’s important to reduce air pollution from all sources,” Avellaneda says. However, it should be noted that road traffic in an urban environment is the main source of air pollutant emissions. It is therefore necessary to implement policies to reduce air pollution even more drastically.” When asked if she thinks people will be willing to leave their cars parked more often, she is short. “I think if their health is at stake, yes.”

The study shows how important the environment is for stroke risk. And to further curb that opportunity, Avellaneda would like to see more urban parks and green belts in cities. “More than 75 percent of Europe’s population lives in urban areas,” she says. “However, city dwellers often have limited access to natural environments. We believe the results of this study support the need for greener cities, given the important health benefits they can deliver.” In addition, the researchers argue that we should strive to realize more sustainable towns and cities, where living no longer entails an increased risk of disease.