It seems people still use the intelligence quotient (IQ) test even though minorities in America claim there is cultural bias that invalidates it as a measure of intelligence.
Researchers at the Columbia Center for Children's Environmental Health (CCCEH) at the Mailman School of Public Health have gone even further than cultural bias; they say prenatal exposure to environmental pollutants called polycyclic aromatic hydrocarbons (PAHs) can affect a child's IQ, according to their study of black and hispanic women living in New York City.
PAHs are chemicals released into the air from the burning of coal, diesel, oil and gas, or other organic substances such as tobacco. In urban areas motor vehicles are a major source of PAHs.
The study found that children exposed to high levels of PAHs in New York City had full scale and verbal IQ scores that were 4.31 and 4.67 points lower, respectively than those of less exposed children. High PAH levels were defined as above the median of 2.26 nanograms per cubic meter (ng/m3).
The study included children who were born to non-smoking Black and Dominican American women age 18 to 35 who resided in Washington Heights, Harlem or the South Bronx in New York. The children were followed from in utero to 5 years of age. The mothers wore personal air monitors during pregnancy to measure exposure to PAHs and they responded to questionnaires.
"These findings are of concern because these decreases in IQ could be educationally meaningful in terms of school performance," says Frederica Perera, DrPH, professor of Environmental Health Sciences and director of the CCCEH at Columbia University Mailman School of Public Health and study lead author. "The good news is that we have seen a decline in air pollution exposure in our cohort since 1998, testifying to the importance of policies to reduce traffic congestion and other sources of fossil fuel combustion byproducts."
At 5 years of age, 249 children were given an intelligence test known as the Wechsler Preschool and Primary Scale of the Intelligence, which provides verbal, performance and full-scale IQ scores. The researchers developed models to calculate the associations between prenatal PAH exposure and IQ. They accounted for other factors such as second-hand smoke exposure, lead, mother's education and the quality of the home caretaking environment.
Study participants exposed to air pollution levels below the average were designated as having "low exposure," while those exposed to pollution levels above the average were identified as "high exposure." A total of 140 children were classified as having high PAH exposure.
"The decrease in full-scale IQ score among the more exposed children is similar to that seen with low-level lead exposure," noted Dr. Perera. "This finding is of concern because IQ is an important predictor of future academic performance, and PAHs are widespread in urban environments and throughout the world. Fortunately, airborne PAH concentrations can be reduced through currently available controls, alternative energy sources and policy interventions."
Mailman School of Public Health's Li Zhigang, Robin Whyatt, Lori Hoepner, Shuang Wang, David Camann, and Virginia Rauh were co-authors of the study.
Funded by the National Institute of Environmental Health Sciences (NIEHS), a component of the National Institutes of Health, the U.S. Environmental Protection Agency and several private foundations.
The study findings are published in the August 2009 issue of Pediatrics.
- PHYSICAL SCIENCES
- EARTH SCIENCES
- LIFE SCIENCES
- SOCIAL SCIENCES
Subscribe to the newsletter
Stay in touch with the scientific world!
Know Science And Want To Write?
- Will Aspartame Critics Now Be Less Bitter?
- New Ice Age Is Coming, By 2030, Says Analysis
- (Well)-Paid PhD Position In Physics Offered In Padova, Italy
- New Results From The LHC At 13 TeV!
- An Anti-Aging Pill Is Still A Long Way Off
- People Are Not Scared Of GMO Warning Labels
- Scientists Discover First 'DNA Ambulance'
- "Thanks doc bloom for the thoughtful article, but I still prefer sugar vs aspartame because of taste..."
- "Methanol (wood alcohol) is 11% of aspartame, so one can diet drink gives 22 mg methanol, which..."
- "Josh, this is one of best articles I've read!..."
- "There are two zero-entries data points not shown (semi-log graph).Nobody gets excited by two events..."
- "That was a pun! Excesses usually appear toward the end of a spectrum... and the energy being 1..."