title: Impacts of prenatal exposures to polychlorinated biphenyls, methylmercury, and lead on intellectual ability of 42-month-old children in Japan.
abstract: BACKGROUND
  The age-specific impacts of perinatal exposures to polychlorinated biphenyls (PCB), methylmercury (MeHg), and lead on child neurodevelopment remain controversial. Since we have already reported the prenatal effects of these chemicals on neurodevelopment in 3-day-old and 30-month-old children of a birth cohort, the following effects were analyzed in the 42-month-old children in the same cohort.
  
  
  METHODS
  The Kaufman Assessment Battery for Children (K-ABC), comprised of four scales, was used to assess their intelligence and achievement. The relationships between the chemicals and K-ABC scores were analyzed using multivariate analyses.
  
  
  RESULTS
  The median values of chemicals in cord blood of 387 children were 46.5 (5th and 95th percentiles, 16.7-115.7)ng/g-lipid for total PCB, 10.1 (4.3-22.2)ng/g for total mercury (THg), and 1.0 (0.5-1.8) μg/dL for lead. Of the highly chlorinated PCB homologs, 9 CBs was negatively correlated with the sequential and mental processing score of the K-ABC (p<0.05). There were no significant correlations between any K-ABC score and either THg or lead. The negative effect of 9 CBs remained even after adjusting for THg, lead, and other confounders. The K-ABC scores were significantly lower in the boys than in the girls, and the standardized β of 9 CBs for the sequential and mental processing scores in multiple regression analysis was statistically significant in boys.
  
  
  CONCLUSIONS
  These findings suggest that intellectual ability in the developmental stage may be impaired by prenatal exposures to highly chlorinated PCB homologs, especially in Japanese boys.
authors.affiliation: Development and Environmental Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Miyagi, Sendai 980-8575, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Tatsuta
authors.affiliation: Development and Environmental Medicine, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Miyagi, Sendai 980-8575, Japan. Electronic address: nakaik@med.tohoku.ac.jp.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Nakai
authors.affiliation: Environmental Health Sciences, Akita University Graduate School of Medicine, Akita 010-8543, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Murata
authors.affiliation: Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.
authors.forename: Keita
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Iwai-Shimada
authors.affiliation: Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kurokawa
authors.affiliation: Human Development and Disabilities, Tohoku University Graduate School of Education, Sendai 980-8576, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Hosokawa
authors.affiliation: Environmental Health Sciences, Tohoku University Graduate School of Medicine, Sendai 980-8575, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Satoh
mesh_terms: D002657:Child Development / Q000187:drug effects; D002675:Child, Preschool; D003071:Cognition / Q000187:drug effects*; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D007564:Japan; D007854:Lead / Q000009:adverse effects* / Q000097:blood; D008297:Male; D008767:Methylmercury Compounds / Q000097:blood / Q000506:poisoning*; D011078:Polychlorinated Biphenyls / Q000097:blood / Q000506:poisoning*; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects
chemical_list: D008767:Methylmercury Compounds; D007854:Lead; D011078:Polychlorinated Biphenyls
keywords: Child intellectual ability; Highly chlorinated PCB; Lead; Methylmercury; Polychlorinated biphenyls