Air pollution linked with brain shrinkage in older women

18 November 2020

New research published today (Wednesday 18 November) in Neurology suggests women living in areas of high pollution in the US are at increased risk of brain shrinkage.

What the researchers did

The researchers looked at women free of dementia at the start of the study.

The scientists worked out the levels of particulate matter – a mixture of solid particles and liquid droplets from the burning of fossil fuels – people living at certain ZIP codes were exposed to three years before a first MRI brain scan.

A total of 712 women had a repeated the MRI brain scans five years later.

What did the researchers find?

Researchers then used machine learning to measure patterns of brain shrinkage seen in the MRI scans to work out whether the women were at increased risk of Alzheimer’s disease.

Scientists found increased exposure to air pollution was linked with more brain shrinkage over five years. They worked out this was equivalent to a 24% increased risk of Alzheimer’s disease.

The increased risk remained even after considering other factors that could have affected brain shrinkage.

What did our expert say?

Sara comments on morning sleep and dementiaDr Sara Imarisio, Head of Research at Alzheimer’s Research UK, said:

“Dementia isn’t an inevitable part of getting older, with factors including age, genetics and the environment affecting the risk of developing the condition. A growing body of research now suggests air pollution is linked with our dementia risk, particularly in later life.

 

“In this study, scientists found increased brain shrinkage in older women exposed to higher levels of a type of air pollution. The study only looked at older women and did not consider all types of air pollution, but this is a well-conducted piece of work and worryingly found some areas where pollution levels exceeded levels deemed safe by the US government.

“Alzheimer’s Research UK is committed to better understanding how lifestyle and environmental factors throughout our lives can help reduce the risk of dementia, and having clean air for all to breathe should remain a critical public health goal.”

 

Want to read more?

Neurology: PM2.5 associated with grey matter atrophy reflecting increased Alzheimers risk in older women