Exposure to air pollution nanoparticles produced by fuel-burning could increase people’s chances of getting brain cancer, according to a study from McGill University in Canada.
The study, which was published in the journal Epidemiology is the first study to suggest a relationship between air pollution and brain tumours.
The research was done in collaboration with investigators at Health Canada and Statistics Canada and researchers analysed the medical records and pollution exposure of 1.9 million adult Canadians across the country from 1991 to 2016.
They assigned ultrafine particle (UFP) exposures to residential locations using land-use regression models with exposures updated to account for mobility within and between cities.
Models which accounted for age, sex and immigration status were also used to estimate hazard ratios.
The researchers found that a 10,000 cubic centimetre (cm3) increase in UFPs was positively associated with incidences of brain tumours.
They then followed up cohort members for malignant brain tumours between 2001 and 2015, which identified 1,400 during each follow-up period.
The researchers have therefore concluded that ambient UFPs may represent a previously unrecognised risk factor for brain tumours in adults.
Scott Weichenthal, lead author of the study from the Department of Epidemiology, Biostatistics and Occupational Health at McGill University 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 a lot of cases. In a large city, it could be a meaningful number.’
There is now a growing body of evidence that suggests air pollution damages how the brain works.
A study in May suggested a link between transport-related air pollution and childhood anxiety.
They found that children who had been exposed to higher levels of transport-related air pollution there were significant increases of the hormone myo-inositol in the brain due to inflammation, which they believe was caused by air pollution, compared to those with a low exposure.
In August, researchers found a ‘significant link’ between exposure to air pollution in childhood and developing mental illnesses such as bipolar disorder, schizophrenia and depression later in life.
The study found that the US counties with the worst air quality had a 27% increase in cases of bipolar disorder and a 6% increase in cases of major depression when compared to those with the best air quality.