31-05-06

Children exposed to high levels of city air pollution while in the womb are nearly three times more likely to have mental deficiencies than other kids, an explosive Columbia University study has found.
The analysis compared the learning ability of 183 3-year-olds from Harlem, Washington Heights and the South Bronx with the level of pollutants they were exposed to before birth. The moms wore air monitors while they were pregnant, and the kids are being studied over a number of years.

The study found that 42 kids exposed to the highest readings of polycyclic aromatic hydrocarbons in utero -- mostly exhaust fumes from cars, buses and trucks, as well as power generators -- scored 5.7 points lower on cognitive tests than did kids in the sample who were subjected to lower levels of pollutants. The scores were 6 % lower than the other kids -- but that means the risk of being developmentally disabled for the most-exposed 3-year-olds was 2.9 times greater, because the kids tended to fall below a crucial cut-off score.
Such delays in cognitive development could lead to academic difficulties in literacy and math when the youngsters attend school, the study authors claim.

The researchers said the findings were groundbreaking because they were unaware of any other inquiry linking exposure of pollutants in the womb to the mental development of kids several years later. Prior studies have shown that pollutants can reduce foetal growth.
In-utero exposure to pollutants did not have a significant impact on mental development at ages 1 and 2, the report said, and researchers do not know why it took time for the problems to appear.

"This is the first time it's been shown that in-utero exposure to air pollutants is linked to delayed cognitive development at age 3," said chief researcher Dr Frederica Perera, director of the Columbia University Centre for Children's Environmental Health. "They had a significant drop in scores."
She added, "These findings are of concern, because compromised mentalperformance in the preschool years is an important precursor to subsequent educational performance deficits”.

The researchers said they enrolled the affected children in state preschool "intervention" programs to help correct the developmental delays they had found. The Columbia study focused on moms and kids in neighbourhoods surrounding the university, and most of the participants were black and Latino. But Perera said the results were consistent across the race and gender of the kids.
Environmental advocates have long complained that kids in these neighbourhoods suffer from higher rates of asthma because of air pollutants caused by bus and truck traffic. But Perera said the type of urban air pollutants cited in the study are "very pervasive" throughout much of the city.

The mothers who participated in the study were non-smokers, and the researchers controlled for second-hand smoke. The moms carried air monitors during the third trimester of pregnancy.
Umbilical-cord blood was also collected during delivery, to be tested for pollutants.