Researchers at Lancaster University in the United Kingdom studying the effects of lifelong exposure to air pollution have found markers for Alzheimer's, Parkinson's and motor neurone disease, or MND, among children as young as 11 months old.

The study focused on residents of Mexico City, and was led by Lilian Calderon-Garciduena of the Universidad del Valle de Mexico, along with researchers from Germany, India and the United States.

It examined the brainstems of 186 people aged between 11 months and 27 years old, and followed up previous research linking pollution to Alzheimer's disease, and the discovery of nanoparticles from air pollution in the brain's frontal cortex.

The latest study also found them in the brainstem, the area at the back of the brain that controls functions including balance, heart and breathing rates. This has led researchers to say that such pollution, however ingested, can put people at risk of potential harm.

"Not only did the brainstems of the young people in the study show the neuropathological hallmarks of Alzheimer's, Parkinson's and MND," said Barbara Maher from the Lancaster Environment Centre, "they also had high concentrations of iron, aluminum and titanium-rich nanoparticles in the brainstem."

Lancaster has long-established teaching, student exchange and research links with institutions including the Chinese Academy of Sciences, Guangdong University of Foreign Studies and South China University of Technology.

The particles discovered were described as being "strikingly similar" to those produced by pollution from engines and braking systems, and were also found in the gut wall, suggesting they can be absorbed by the digestive system and then work their way up to the brain.

"Different people will have different levels of vulnerability to such particulate exposure but our new findings indicate that what air pollutants you are exposed to, what you are inhaling and swallowing, are really significant in development of neurological damage," Maher added.

Brainstem samples from a control group of similarly aged and gendered people from a less-polluted area did not show the same levels of degeneration.

Figures published by the World Health Organization in September 2020 showed that around 50 million people worldwide are living with forms of dementia, with Alzheimer's accounting for between 60 and 70 percent of cases. Of those patients, around 10 million are in China.