City pollution affects children's memory, IQ

Children living in cities with significant air pollution are at an increased risk of detrimental impacts to the brain, including short-term memory loss and lower IQ, says a study.

Air pollution interacts with a gene called apolipoprotein epsilon 4 allele to lower children's IQ by as much as 10 points, the findings showed.

"A IQ difference of 10 points will likely have a negative impact on academic and social issues, including bullying and teen delinquency," said Lilian Calderon-Garciduenas, professor at the University of Montana in the US.

Those with lifetime exposures to high level of air pollutants, including fine particulate matter, are at an increased risk for brain inflammation and neurodegenerative changes, including Alzheimer's and Parkinson's diseases, the findings showed.

Children, who live in a polluted environment and also carry the apolipoprotein epsilon 4 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 epsilon 3 allele.

The study matched two groups of children living in Mexico City using multiple variables, including age, gender, socio-economic status and education, among others.

They then compared children carrying the epsilon 4 allele to children carrying the epsilon 3 allele and found that those with the former 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 study appeared in the Journal of Alzheimer's Disease.