Air pollution is known to harm the heart and lungs, but a new study suggests it may also increase the risk of developing certain types of brain tumours.
Researchers have found a possible link between air pollution and meningioma – a common, usually noncancerous tumour that grows in the lining of the brain and spinal cord.
The study, published in the journal Neurology, involved nearly 4 million adults in Denmark, with an average age of 35. These individuals were observed over a 21-year period.
During that time, 16,596 people developed brain and spinal cord tumours, and 4,645 of them had meningioma. The researchers observed that individuals more exposed to air pollutants, particularly those from traffic, had a higher risk of developing this type of tumour.
The study focused on air pollutants such as nitrogen dioxide and ultrafine particles, which are commonly found in urban areas. These tiny particles can be small enough to enter the brain by crossing the blood-brain barrier, possibly harming brain tissue.
“Long-term exposure to pollution, especially from traffic, may play a role in the development of meningioma,” said Ulla Hvidtfeldt, a researcher from the Danish Cancer Institute. “This adds to growing evidence that air pollution can affect not just the heart and lungs, but the brain as well.”
However, the study did not find a strong link between air pollution and more aggressive brain tumours, such as gliomas.
The researchers emphasised that their findings indicate a connection, rather than a direct cause. Further studies are necessary to fully understand the exact impact.
Still, experts believe that reducing air pollution could have important benefits for public health. As Hvidtfeldt noted, “If cleaning up our air can help lower the risk of brain tumours, that could make a real difference.”
