JOIN USChildren living in cities with significant air pollution are at an increased risk for detrimental impacts to the brain, including short-term memory loss and lower IQ, a new study has found.
Researchers show that children with lifetime exposures to concentrations of air pollutants above the current US standards, including fine particulate matter, are at an increased risk for brain inflammation and neurodegenerative changes, including Alzheimer's and Parkinson's diseases.
The study found that clinically healthy children who live in a polluted environment and who also carry a gene - the apolipoprotein e4 allele, already known to increase a person's risk of developing Alzheimer's disease - demonstrated compromised cognitive responses when compared with children carrying a gene with apolipoprotein e3 allele.
Metropolitan Mexico City is an example of extreme urban growth and serious environmental pollution, where 8 million children are involuntarily exposed to harmful concentrations of fine particulate matter in the air every day beginning at conception, researchers said.
The study matched two groups of children living in Mexico City by multiple variables, including age, gender, socioeconomic status and education, among others.
Researchers then compared children carrying the e4 allele to children carrying the e3 allele and found that those with the e4 allele had three significant alterations.
They had short-term memory shortfalls, an IQ that while within the normal limits measured 10 points less, and changes in key metabolites in the brain that mirror those of people with Alzheimer's disease.
"The results add to growing data suggesting e4 carriers could have a higher risk of developing early Alzheimer's disease if they reside in a polluted urban environment," said Dr Lilian Calderon-Garciduenas from the University of Montana.
She said the study also raises concerns about important educational issues. Since Mexico City children mostly attend underprovided public schools, children do not build cognitive reserves that serve as a defence to pollution impacts.
"An IQ difference of 10 points will likely have a negative impact on academic and social issues, including bullying and teen delinquency," she said.
The authors argue that sustained exposures to urban air pollution result in cognitive underperformance and metabolic brain changes that could lead to an acceleration of neurodegenerative changes.
Air pollution is a serious public health issue, and exposures to concentrations of air pollutants at or above the current standards have been linked to neuroinflammation and neuropathology. The study was published in the Journal of Alzheimer's Disease