What is the link between pollution and Alzheimer's disease?

In recent years, much progress has been made on Alzheimer's disease. Neuroscientists have in particular highlighted various factors contributing to the appearance and evolution of the disease. Recently, a new study found a new factor associated with cognitive decline and memory loss: fine particle pollution. This would lead to long-term brain changes, altering cognitive functions.

According to USC researchers, 70- and 80-year-old women who have been exposed to higher levels of air pollution have experienced greater reductions in memory and brain atrophy similar to Alzheimer's compared to their counterparts who breathed cleaner air. The study was published in the journal Brain.

" This is the first study that actually shows, in a statistical model, that air pollution was associated with changes in people's brains, and that these changes were then linked to a decrease in memory performance, " says Andrew Petkus. , neurologist at the Keck School of Medicine at USC.

" We hope that through a better understanding of the underlying brain changes caused by air pollution, researchers will be able to develop interventions to help people with cognitive decline or at risk of developing one ."

A link between fine pollution particle  and Alzheimer's disease

Fine particles, also called PM2.5 particles, are about 1/30 the width of a human hair. They come from the exhaust of traffic, smoke and dust. Their small size allows them to stay in the air, to enter buildings, to be easily inhaled, and to accumulate in the brain. Particulate matter pollution is associated with asthma, cardiovascular disease, lung disease and premature death.

Previous research has suggested that exposure to fine particle pollution increases the risk of Alzheimer's disease and related dementias. However, scientists did not know if PM2.5 alter brain structure and accelerate the decline of memory.

For this study, researchers used data from 998 women aged 73 to 87, who had up to two brain exams five years apart, as part of the Women's Health Initiative . The Women's Health Initiative was launched in 1993 by the National Institutes of Health. More than 160,000 women have been recruited to treat issues related to heart disease, cancer and osteoporosis.

Brain changes are independent of origin, education or income

These brain scans were scored on the basis of their similarity to Alzheimer's disease patterns by a machine learning tool "trained" via brain scans of people with the disease. The researchers also collected information on the place of residence of the 998 women, as well as environmental data from these sites to estimate their exposure to fine particle pollution.

When all this information was combined, researchers found the link between increased exposure to pollution, changes in the brain, and memory problems, even after adjusting for differences in income, education, origin, region, smoking and other factors.

" This study provides another piece of the puzzle of Alzheimer's disease by identifying some of the brain changes that link air pollution and memory decline. Each research study brings us closer to a cure for Alzheimer's disease, "concludes Petkus.


Particulate matter and episodic memory decline mediated by early neuroanatomic biomarkers of Alzheimer’s disease

Diana Younan, Andrew J Petkus, Keith F Widaman, Xinhui Wang, Ramon Casanova, Mark A Espeland, Margaret Gatz, Victor W Henderson, JoAnn E Manson, Stephen R Rapp, Bonnie C Sachs, Marc L Serre, Sarah A Gaussoin, Ryan Barnard, Santiago Saldana, William Vizuete, Daniel P Beavers, Joel A Salinas, Helena C Chui, Susan M Resnick, Sally A Shumaker, Jiu-Chiuan Chen

Brain, awz348,


Published: 20 November 2019

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