title: Home environment and prenatal exposure to lead, arsenic and zinc on the neurodevelopment of six-month-old infants living in Chitwan Valley, Nepal.
abstract: BACKGROUND
  We have previously reported the inverse associations between in utero levels of lead (Pb), arsenic (As) (i.e., toxic elements), and neurodevelopmental indicators (i.e., motor and state regulation cluster score) measured by the Brazelton Neonatal Behavioral Assessment Scale, third edition (NBAS III) in this cohort at birth. Using additional follow-up, this study investigated the effects of cord blood levels of Pb, As, and zinc (Zn) (an essential element) and the postnatal environment on the neurodevelopment of 6-month-old infants in Chitwan Valley, Nepal.
  
  
  METHODS
  In total, 100 mother-infant pairs were recruited from Chitwan District, Nepal. Pb, As, and Zn concentrations in cord blood were measured. Postnatal raising environment (i.e., HOME score or home environment hereafter) was evaluated using the Home Observation for Measurement of Environment (HOME) scale. Neurodevelopment of infants at 6 months (n=94) was assessed according to the Bayley Scale of Infant Development, second edition (BSID II). Multivariable regression adjusting for covariates was performed to determine the associations of in utero levels of toxic and essential elements and the home environment with neurodevelopment scores.
  
  
  RESULTS
  Cord blood levels of Pb, As, and Zn were not associated with any BSID II cluster scores in 6-month-old infants. The total HOME score was positively associated with the Psychomotor Development Index (PDI) score (coefficient=0.59, 95% confidence interval [CI]=0.04 to 1.13).
  
  
  CONCLUSIONS
  In this cohort, detrimental effects of in utero Pb and As on neurodevelopmental indicators observed at birth did not persist at 6 months of age, while it showed an association between the neurodevelopment and home environment.
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, Japan. Electronic address: parajulirp@humeco.m.u-tokyo.ac.jp.
authors.forename: Rajendra P
authors.initials: RP
authors.lastname: Parajuli
authors.affiliation: Department of Social Medicine, National Research Institute for Child Health and Development, Tokyo, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Umezaki
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, Japan.
authors.forename: Hana
authors.initials: H
authors.lastname: Furusawa
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Watanabe
mesh_terms: D001151:Arsenic / Q000097:blood; D020261:Arsenic Poisoning / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D002658:Developmental Disabilities / Q000097:blood / Q000209:etiology*; D004785:Environmental Pollutants; D005260:Female; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D007223:Infant; D007855:Lead Poisoning / Q000097:blood / Q000453:epidemiology* / Q000503:physiopathology; D008297:Male; D009390:Nepal / Q000453:epidemiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000453:epidemiology / Q000503:physiopathology*; D015032:Zinc / Q000097:blood
chemical_list: D004785:Environmental Pollutants; D015032:Zinc; D001151:Arsenic
keywords: Bayley Scale of Infant Development; HOME scale; Nepal; Neurodevelopment; Toxic and essential elements