New US research has found that growing up in a city with a high level of air pollution could increase the risk of Alzheimer’s disease and progression of the disease.
Carried out by researchers at the University of Montana, the study looked at the effects of air pollution in Mexico City, where 24 million people in the metropolitan area are exposed daily to concentrations of fine particulate matter (PM2.5) and ozone pollution above US Environmental Protection Agency standards.
The team looked at 203 autopsies of Mexico City residents, who ranged in age from 11 months to 40 years, to measure the levels of two abnormal proteins which indicate the development of Alzheimer’s — hyperphosphorylated tau and beta amyloid.
The results showed that 99.5 percent of the subjects examined showed signs of Alzheimer’s disease, with the early stages of the disease even found in babies less than a year old.
The young adult city dwellers, who had had a lifetime of exposure to PM2.5, also showed high levels of both proteins in the brain.
In addition to the proteins tau and amyloid, the team also looked at the gene apolipoprotein E (APOE 4), which is a well-known risk factor for Alzheimer’s.
This time the team found that not only was the progression of Alzheimer’s related to age and PM2.5 exposure, but it was also linked with APOE 4, with APOE 4 carriers showing a higher risk of rapid progression of the disease as well as 4.92 higher odds of committing suicide compared to those who don’t carry the gene.
The team concluded that exposure to PM2.5 had a negative effect on the progression of the disease due to the tiny pollution particles entering the brain through the nose, lungs and gastrointestinal tract from where they can travel everywhere in the body through the circulatory system causing damage.
They added in their conclusion that air pollution is one of the key modifiable risk for millions of people across the world, including millions of Americans exposed to harmful particulate pollution levels.”Alzheimer’s disease hallmarks start in childhood in polluted environments, and we must implement effective preventative measures early,” said lead researchers Dr. Lilian Calderón-Garcidueñas. “It is useless to take reactive actions decades later.”
“Neuroprotection measures ought to start very early, including the prenatal period and childhood. Defining pediatric environmental, nutritional, metabolic and genetic risk-factor interactions are key to preventing Alzheimer’s disease.”
The results can be found published online in the journal of Environmental Research.