New research suggests that exposure to air pollution increases the chances of developing meningioma, a tumour that forms in the protective membranes that surround the brain and spinal cord.
Researchers in Denmark followed nearly 4 million adults from 1991 onward, to see whether long-term exposure to air pollution around people’s homes was linked to a higher risk of developing central nervous system (CNS) tumours, including gliomas, meningiomas and tumours of the cranial nerves.
The researchers calculated people’s average exposure to ultrafine particles (UFPs), PM2.5, NO₂ and elemental carbon and compared people with the lowest exposure to those with the highest by dividing people into three groups for each pollutant.
In terms of ultrafine particles, people in the lowest group had an average exposure of 11,041 particles per centimeter cubed (cm³) compared to people with the highest exposure of 21,715 particles/cm³. In these groups, 0.06% of people in the group with the lowest exposure developed meningiomas compared to 0.20% of people with the highest exposure.
Over a 21 year period, 16,596 people developed a tumor of the central nervous system, 4,645 of who developed meningioma.
The results showed that people with higher exposure to air pollutants had a greater risk of developing meningioma:
- For UFP, every increase of 5,747 particles/cm³ increased the risk of developing meningioma by 10%
- For PM2.5, every increase of 4.0 μg/m³ increased the risk of developing meningioma by 21%
- For NO2, every increase of 8.3 μg/m³ increased the risk of developing meningioma by 12%
- For EC, every increase of 0.4 μg/m³ increased the risk of developing meningioma by 3%
The study did not find a clear link between air pollution and other types of brain tumours like gliomas or cranial nerve tumors.
Study author Ulla Hvidtfeldt, PhD, of the Danish Cancer Institute in Copenhagen said: ‘Various types of air pollution have been shown to have negative effects on health, and ultrafine particles are small enough to cross the blood-brain barrier and may directly affect brain tissue.
‘Our study suggests that long-term exposure to air pollution from traffic and other sources may play a role in the development of meningioma and adds to the growing body of evidence that air pollution can affect the brain – not just the heart and lungs.
‘While research on the health effects of ultrafine particles is still in its early stages, these findings point to a possible link between traffic-related ultrafine particle exposure and the development of meningioma.
‘More research is needed to confirm these results, but if cleaning up our air can help lower the risk of brain tumors, that could make a real difference for public health.’
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