Exposure to Environmental Tobacco Smoke and Cognitive Abilities among U.S. Children and Adolescents Kimberly Yolton,1,2 Kim Dietrich,1,3 Peggy Auinger,4 Bruce P. Lanphear,1,2 and Richard Hornung1,3,4 1Cincinnati Children's Environmental Health Center, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; 2Department of Pediatrics and 3Department of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA; 4Department of Pediatrics, University of Rochester School of Medicine and the American Academy of Pediatrics Center for Child Health Research, Rochester, New York, USA; 5Institute for Health Policy and Health Services Research, University of Cincinnati, Cincinnati, Ohio, USA Abstract We used the Third National Health and Nutrition Examination Survey (NHANES III) , conducted from 1988 to 1994, to investigate the relationship between environmental tobacco smoke (ETS) exposure and cognitive abilities among U.S. children and adolescents 6-16 years of age. Serum cotinine was used as a biomarker of ETS exposure. Children were included in the sample if their serum cotinine levels were 15 ng/mL, a level consistent with ETS exposure, and if they denied using any tobacco products in the previous 5 days. Cognitive and academic abilities were assessed using the reading and math subtests of the Wide Range Achievement Test-Revised and the block design and digit span subtests of the Wechsler Intelligence Scale for Children-III. Analyses were conducted using SUDAAN software. Of the 5,365 6- to 16-year-olds included in NHANES III, 4,399 (82%) were included in this analysis. The geometric mean serum cotinine level was 0.23 ng/mL (range, 0.035-15 ng/mL) ; 80% of subjects had levels < 1 ng/mL. After adjustment for sex, race, region, poverty, parent education and marital status, ferritin, and blood lead concentration, there was a significant inverse relationship between serum cotinine and scores on reading (ß = -2.69, p = 0.001) , math (ß = -1.93, p = 0.01) , and block design (ß = -0.55, p < 0.001) but not digit span (ß = -0.08, p = 0.52) . The estimated ETS-associated decrement in cognitive test scores was greater at lower cotinine levels. A log-linear analysis was selected as the best fit to characterize the increased slope in cognitive deficits at lower levels of exposure. These data, which indicate an inverse association between ETS exposure and cognitive deficits among children even at extremely low levels of exposure, support policy to further restrict children's exposure. Key words: children, cognition, environment, environmental tobacco smoke, epidemiology. Environ Health Perspect 113:98-103 (2005) . doi:10.1289/ehp.7210 available via http://dx.doi.org/ [Online 7 October 2004] Address correspondence to K. Yolton, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., MLC 7035, Cincinnati, OH 45229-3039 USA. Telephone: (513) 636-2815. Fax: (513) 636-4402. E-mail: kimberly.yolton@cchmc.org This paper was presented in part at the annual meeting of the Pediatric Academic Society, May 2002. The authors declare they have no competing financial interests. Received 27 April 2004 ; accepted 7 October 2004 . The full version of this article is available for free in HTML or PDF formats. |