title: Tooth lead levels and IQ in school-age children: the Port Pirie Cohort Study.
abstract: The relation between lead concentration in deciduous central upper incisor teeth and intellectual functioning was examined in 262 children who were followed from birth to age 7 years in the lead smelter town of Port Pirie, South Australia, and its environs. Intellectual functioning of the children was assessed over the 3-year period from 1986 to 1989 with the revised Wechsler Intelligence Scale for Children (WISC-R) while each child was in his or her eighth year. There was an inverse relation between tooth lead concentration and intellectual development; the intelligence quotient declined by 2.6 points (90% confidence interval (CI) 0.13-4.9) for each natural-log unit increase in tooth lead concentration, expressed in parts per million. Some WISC-R subscales were more strongly associated with lead exposure than others. In particular, tooth lead was significantly negatively associated with scores for the "Block Design" test (partial regression coefficient -1.25 points per unit of natural-log tooth lead; 90% CI -0.61 to -1.89). No statistically significant interaction between a child's sex and tooth lead concentration was found for any of the WISC-R scales. These findings are in agreement with previously published results from this cohort for which serial blood lead concentrations were used to estimate lifetime lead burden.
authors.affiliation: Department of Community Medicine, Medical School, University of Adelaide, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: McMichael
authors.forename: P A
authors.initials: PA
authors.lastname: Baghurst
authors.forename: G V
authors.initials: GV
authors.lastname: Vimpani
authors.forename: N R
authors.initials: NR
authors.lastname: Wigg
authors.forename: E F
authors.initials: EF
authors.lastname: Robertson
authors.forename: S
authors.initials: S
authors.lastname: Tong
mesh_terms: D002648:Child; D015331:Cohort Studies; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D006801:Humans; D007360:Intelligence / Q000502:physiology*; D007854:Lead / Q000032:analysis*; D007855:Lead Poisoning / Q000503:physiopathology*; D008297:Male; D015999:Multivariate Analysis; D012044:Regression Analysis; D013021:South Australia; D014070:Tooth / Q000737:chemistry*; D014888:Wechsler Scales
chemical_list: D007854:Lead