The Effects Are Seen As Reduced Scores on Mental Development Tests at Age Two
New York, NY — March 8, 2004 — The effect on mental development of prenatal exposure to second-hand smoke is magnified for children with socioeconomic disadvantage, according to a new study by the Columbia Center for Children’s Environmental Health, part of the Mailman School of Public Health at Columbia University.
The study found that children whose mothers are exposed during pregnancy to second-hand smoke have reduced scores on tests of cognitive development at age two, when compared to children from smoke-free homes. The reduction amounts to almost five developmental quotient points (out of an average score of 100). In addition, the children exposed to second-hand smoke are twice as likely to have developmental scores below 80, indicative of developmental delay.
The reduction in cognitive development is magnified for socioeconomically disadvantaged children whose mothers lived in inadequate housing or had insufficient food or clothing during pregnancy. The combined effect results in a deficit of about seven points in cognitive development. The study will be published in the peer-reviewed journal Neurotoxicology and Teratology.
“These findings reveal the dangers for pregnant women and their unborn children of multiple ‘toxic’ exposures — both chemical and socioeconomic,” said Dr.Virginia Rauh, a Deputy Director of the Center and Associate Professor at the Mailman School of Public Health and principal author of the study. “They show, for the first time, that urban children exposed to both conditions experience a kind of double jeopardy with consequences persisting into early childhood and possibly beyond.”
“This finding reinforces the need to prevent serious developmental problems in children by addressing harmful prenatal exposures,” said Dr. Frederica P. Perera, Director of the Center and the study team leader. “From a health policy standpoint, it is important both to limit exposure to second-hand smoke and to better the living conditions of pregnant women and their children.”
The research involved a sample of 226 infants of non-smoking African American and Dominican women in Washington Heights, Central Harlem and the South Bronx. Each of the women was interviewed during the third trimester of pregnancy, for approximately 45 minutes, by a specially trained bilingual interviewer. From those interviews, data were obtained on their exposure to second-hand smoke, also known as Environmental Tobacco Smoke (ETS), and on their socioeconomic status and living conditions. The ETS exposure was further validated using a short-term biomarker of exposure: the level of cotinine in the umbilical cord blood at the time of delivery.
This study is part of a broader, multi-year research project, “The Mothers & Children Study In New York City,” started in 1998, which examines the health effects of exposure of pregnant women and babies to air pollutants from vehicle exhaust, the commercial burning of fuels, and tobacco smoking, as well as from residential use of pesticides, and cockroach and mouse allergens.
This study was made possible by research grants from the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency, as well as a number of generous private foundations. Other co-authors of this study include Drs. Robin Whyatt, Robin Garfinkel, and Howard Andrews of the Center, as well as Lori Hoepner, Andria Reyes, and Diurka Diaz of CCCEH and David Camann from Southwest Research Institute.