Prenatal secondhand smoke harder on poor children

AORN Journal, May, 2004

The effects of prenatal exposure to secondhand smoke on mental development are exacerbated in children who experience socioeconomic hardships during the first two years of life, according to a March 15, 2004, news release from the National Institutes of Health. Though study data indicate that prenatal exposure to secondhand smoke can be harmful to unborn children regardless of socioeconomic conditions, they also suggest that children from lower-income families may be less able to compensate for these effects during the next few years of life.

The study, conducted by researchers at the Columbia Center for Children's Environmental Health, part of the Mailman School of Public Health at Columbia University, New York, found that children whose mothers were exposed to secondhand smoke during pregnancy had lower scores on tests of cognitive development at age two than children from smoke-free homes. The difference amounted to almost five developmental quotient points out of an average score of 100. Further, the children who were exposed to secondhand smoke in utero were approximately twice as likely to have developmental scores of less than 80, which is indicative of developmental delay. These differences were magnified for children whose mothers lived in inadequate housing or had insufficient food or clothing during pregnancy. The combined effect was a developmental deficit of approximately seven points in tests of cognitive performance. Although the influence of material hardship on the association between secondhand smoke and cognitive development was measured during the postnatal period, the test results show that the children's postnatal exposure to secondhand smoke did not confer any additional risk for developmental deficit over and above that caused by prenatal exposure alone.

The research involved a sample of 226 infants of nonsmoking African American and Dominican women in Washington Heights, Central Harlem, and the South Bronx, New York. Each of the women was interviewed during the third trimester of pregnancy for approximately 45 minutes by a specially trained bilingual interviewer. From the interviews, data were obtained on participants' exposure to secondhand smoke and on their socioeconomic status and living conditions. Secondhand smoke exposure was validated further using a short-term biomarker of exposure--the Level of cotinine in the umbilical cord blood at the time of delivery.

Study Shows Effects of Prenatal Exposure to Secondhand Smoke Greater for Socioeconomically Disadvantaged Children (news release, Bethesda Md: National Institutes of Health, March 15, 2004) http://www.nih .gov/news/pr/mar2004/niehs-15.htm (accessed 25 March 2004).