Polluted cities pose increased Alzheimer’s risk to children

By Johntarantino1 [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons

Children living in the world’s most polluted cities are at increased risk of Alzheimer’s and suicide, claims a University of Montana study.

Researchers studied 203 autopsies of Mexico City residents ranging in age from 11 months to 40 years. Mexico City is home to 24 million people who are exposed daily to concentrations of fine particles and ozone above U.S. regulations.


They tracked two abnormal proteins that indicate development of Alzheimer’s, and also detected the early stages of the disease in babies less than a year old. The research team was led by Dr. Lilian Calderón-Garcidueñas,a physician and Ph.D. toxicologist in the university’s Department of Biomedical and Pharmaceutical Sciences.

She said: “Alzheimer’s disease hallmarks start in childhood in polluted environments, and we must implement effective preventative measures early – it is useless to take reactive actions decades later.” The research was published in the Journal of Environmental Research and is available online.

Risk factor

The scientists found heightened levels of the two abnormal proteins – hyperphosphorylated tau and beta amyloid – in the brains of young ‘urbanites’ – city dwellers – with lifetime exposures to fine-particulate-matter pollution (PM2.5). They also tracked Apolipoprotein E (APOE 4), a well-known genetic risk factor for Alzheimer’s, as well as lifetime cumulative exposure to unhealthy levels of PM2.5  – particles which are at least 30 times smaller than the diameter of a human hair and frequently cause the haze over urban areas.

Their findings indicate that Alzheimer’s starts in early childhood, and the disease progression relates to age, APOE 4 status and particulate exposure. The team also discovered hallmarks of the disease among 99.5 per cent of the subjects they examined in Mexico City. In addition, APOE 4 carriers have a higher risk of rapid progression of Alzheimer’s and 4.92 higher odds of committing suicide versus APOE 3 carriers, controlling for age and particulate exposure.


Overall, the team documented an accelerated and early disease process for Alzheimer’s in highly exposed Mexico City residents. They believe the detrimental effects are caused by tiny pollution particles that enter the brain through the nose, lungs and gastrointestinal tract, and these particles damage all barriers and travel everywhere in the body through the circulatory system.

Their conclusion is that ambient air pollution is a key modifiable risk for millions of people across the globe, including millions of Americans who are exposed to harmful particulate pollution levels.

“Neuroprotection measures ought to start very early, including the prenatal period and childhood,” added Calderón-Garcidueñas. “Defining pediatric environmental, nutritional, metabolic and genetic risk-factor interactions are key to preventing Alzheimer’s disease.”

Author: Simon Weedy

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