Air Pollution Particles Linked to Alzheimer's Found in Young People's Brain Stems

It is believed these nanoparticles can cause damage to molecules in a similar way to conditions such as Alzheimer's and Parkinson's.

More than nine in ten people worldwide live in areas where the air is deemed unsafe due to pollutants, the Daily Mail reported.

Previous studies have also found air pollution is correlated with rates of neurodegenerative diseases but there has never been a confirmed causal link.

Researchers hope this study can shed light on a possible physical mechanism that could explain how high levels of pollution leads to a heightened risk of Alzheimer's.

Brains of 186 deceased young people from Mexico City who died suddenly were dissected as part of the study.

They range in age from 11 months old up to 27 years of age.

All of the studied individuals had evidence of pollution in the grey matter and the researchers believe they entered the organ after being inhaled into the bloodstream.

The nanoparticles were discovered in the substantia nigra, an area which is crucial to the progression of Parkinson's disease.

It is also possible the particles wormed their way into the human organs via the nose or gut.

However, in the brains of people who lived in unpolluted areas, and not the smoggy capital of Mexico, there was no sign of the toxic pollutants.

Professor Barbara Mather from Lancaster University told The Guardian that the study is still observational, and it does not imply causality.

'But how could you expect these nanoparticles containing those metal species to sit inert and harmless inside critical cells of the brain?,' she says.

'That's the smoking gun – it seriously looks as if those nanoparticles are firing the bullets that are causing the observed neurodegenerative damage.'

Children are useful for this field of research despite not normally suffering from Alzheimer's or Parkinson's, because their brains are unaffected by other factors, such as alcohol, which can be seen in adult organs.

While the study is concerning and opens up the possibility for future research, it is being taken with some skepticism.

David Dexter, associate director of research at Parkinson’s UK says that although the study builds on research linking air quality with neurodegeneration, the damage to the brains is significantly different to those that have been previously studied.

The authors of the latest study believe the difference in molecular damage might be down to the fact that the study's specimens were from Mexico City, while the Parkinson's UK brain bank houses organs primarily from the UK.

Dr Susan Kohlhaas, director of research at Alzheimer's Research UK, said: 'Air pollution is linked to many adverse health conditions and a growing body of evidence suggests this includes our risk of developing dementia.

'Proteins do build up in the brain years before we see visible dementia symptoms, but more research is needed before we can suggest air pollution drives brain changes associated with disease in children.'