Air pollution directly linked to increased dementia risk

"An analysis of 56 million people has shown that exposure to air pollution increases the risk of developing a particular form of dementia, the third most common type after Alzheimer's disease and vascular dementia. The study, published in Science on 4 September, suggests that there is a clear link between long-term exposure to PM 2.5 - airborne particles that are smaller than 2.5 micrometres in diameter - and the development of dementia in people with Lewy body dementia or Parkinson's disease."

"Lewy body dementia is an umbrella term for two different types of dementia: Parkinson's disease with dementia, and dementia with Lewy bodies. In both cases, dementia is caused by the build-up of α-synuclein (αSyn) proteins into clumps, called Lewy bodies, in the brain's nerve cells, which cause the cells to stop working and eventually die. Studies have suggested that long-term exposure to air pollution from car-exhaust, wildfires and factory fumes, is linked with increased risks of developing neurodegenerative illnesses, including Parkinson's disease with dementia."

"Study co-author Xiaobo Mao, who researches neurodegenerative conditions at Johns Hopkins University in Baltimore, Maryland, says he and his colleagues wanted to determine if PM 2.5 exposure also influenced the risk of developing Lewy body dementia. They analysed 2000-2014 hospital-admissions data from 56.5 million people with Lewy body dementia and Parkinson's disease with or without dementia. The data served to identify people with severe neurological diseases."

Long-term exposure to PM2.5 is associated with increased risk of hospitalization for Lewy body dementia, Parkinson's disease with dementia, and related neurodegenerative conditions. PM2.5 does not necessarily cause Lewy body dementia but can accelerate symptom development in individuals with genetic predisposition. Lewy body dementia includes Parkinson's disease with dementia and dementia with Lewy bodies; both are driven by accumulation of α-synuclein into Lewy bodies that damage and kill nerve cells. Common PM2.5 sources include vehicle exhaust, wildfires, and industrial emissions. Hospital-admissions data from 56.5 million people (2000–2014) were analysed to identify associations between long-term PM2.5 exposure and severe neurological disease. The associations were observed across varied exposure sources and suggest environmental contributions to progression of synuclein-driven neurodegeneration.

Read at Nature