Air pollution nanoparticles have been linked to brain cancer for the first time.
Results from a Canadian study suggest ambient ultra-fine particles (UFPs) may be a previously unrecognised risk factor for incident brain tumours.
UFPs are less than 0.1 micrometre in diameter and in an urban setting are particular prevalent from vehicle emissions, in particular from diesel engines.
Dr Scott Weichenthal at McGill University in Montreal said: “Brain cancers are rare but often fatal. When you multiply these small risks by lots of people, all of a sudden there can be lots of cases. In a large city, it could be a meaningful number.”
Dr Weichenthal analysed medical records and pollution exposure of 1.9 million adult Canadians in Toronto and Montreal from 1991 to 2016. Pollution exposure was based on residential locations and was updated to account for the adults’ residential mobility within cities.
The study found that each 10,000/cm3 increase in average nanoparticle concentration contributes to one new case of brain cancer in a population of 100,000 people.
Combustion-related air pollutants, particularly those from vehicles, are present in urban areas but still little is known about their long-term health impact.
A study from 2016 dicovered magnetic nanoparticles carrying carcinogenic chemicals in the brain. But this new paper, published in Epidemiology, is the first to suggest a relationship with the incidence of brain tumours.
The results are not conclusive, however, and Dr Weichenthal encourages future studies to be conducted with the aim of replicating these results, given the high prevalence of UFP exposures in urban areas around the world.