title: Environmental tobacco smoke exposure and children's intelligence at 8-11 years of age.
abstract: BACKGROUND
  Evidence supporting a link between postnatal environmental tobacco smoke (ETS) exposure and cognitive problems among children is mounting, but inconsistent.
  
  
  OBJECTIVE
  We examined the relationship between ETS exposure, measured using urine cotinine, and IQ scores in Korean school-aged children.
  
  
  METHODS
  The participants were 996 children 8-11 years of age recruited from five administrative regions in South Korea. We performed a cross-sectional analysis of urinary cotinine concentrations and IQ scores obtained using the abbreviated form of a Korean version of the Wechsler Intelligence Scales for Children. Associations were adjusted for potential confounders, and estimates were derived with and without adjustment for mother's Full-Scale IQ (FSIQ) score.
  
  
  RESULTS
  After adjusting for sociodemographic and developmental covariates, urinary cotinine concentrations were inversely associated with FSIQ, Verbal IQ (VIQ), Performance IQ (PIQ), vocabulary, math, and block design scores. Following further adjustment for maternal IQ, only the VIQ scores remained significantly associated with urinary cotinine concentration (B = -0.31; 95% CI: -0.60, -0.03 for a 1-unit increase in natural log-transformed urine cotinine concentration; p = 0.03).
  
  
  CONCLUSIONS
  Urine cotinine concentrations were inversely associated with children's VIQ scores before and after adjusting for maternal IQ. Further prospective studies with serial measurements of cotinine are needed to confirm our findings.
authors.affiliation: Department of Psychiatry, Seoul National Hospital, Seoul, Republic of Korea.
authors.forename: Subin
authors.initials: S
authors.lastname: Park
authors.forename: Soo-Churl
authors.initials: SC
authors.lastname: Cho
authors.forename: Yun-Chul
authors.initials: YC
authors.lastname: Hong
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Kim
authors.forename: Min-Sup
authors.initials: MS
authors.lastname: Shin
authors.forename: Hee Jeong
authors.initials: HJ
authors.lastname: Yoo
authors.forename: Doug Hyun
authors.initials: DH
authors.lastname: Han
authors.forename: Jae Hoon
authors.initials: JH
authors.lastname: Cheong
authors.forename: Bung-Nyun
authors.initials: BN
authors.lastname: Kim
mesh_terms: D002648:Child; D003367:Cotinine / Q000652:urine*; D003430:Cross-Sectional Studies; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000187:drug effects*; D008297:Male; D009035:Mothers; D011446:Prospective Studies; D056910:Republic of Korea; D014028:Tobacco Smoke Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data; D014888:Wechsler Scales
chemical_list: D014028:Tobacco Smoke Pollution; D003367:Cotinine