title: Association of cord blood levels of lead, arsenic, and zinc and home environment with children neurodevelopment at 36 months living in Chitwan Valley, Nepal.
abstract: BACKGROUND
  Inconsistent results continue to be reported from studies linking low-level prenatal lead exposure and child development. Because of limited earlier epidemiological studies with birth cohort follow up design, it still remains inconclusive that either the associations of cord blood level of toxic, and essential elements, and postnatal raising environment on neurodevelopment of children remains constant throughout childhood or change over time.
  
  
  OBJECTIVE
  This study aims to investigate the influence of in utero toxic [lead (Pb) and arsenic (As)] and essential elements [zinc (Zn)] levels on neurodevelopment of 36 months children in Chitwan valley, Nepal taking the postnatal environment into account.
  In this birth cohort study, participants (N=100 mother-infants' pairs) were recruited in Chitwan district, Nepal. We measured Pb, As and Zn concentrations in cord blood. Postnatal raising environment (i.e., Home score or home environment hereafter) was evaluated using Home Observation for Measurement of Environment (HOME) scale. Neurodevelopment of children at 36 months of age (n=70) were assessed using Bayley Scale of Infant Development, Second Edition (BSID II). Multivariate regression was performed (n=70) to see the association of in utero toxic and essential elements level and home environment with neurodevelopment score adjusted for covariates.
  
  
  RESULTS
  Cord blood levels of Pb, As and Zn were not associated with any BSID II cluster scores of 36 months children. The children with relatively superior HOME score and concurrent nutritional status (weight at 36 months) showed better cognitive development (i.e., MDI scores) and motor functions than their counterparts, respectively.
  
  
  CONCLUSIONS
  In this general population in Nepal, prenatal Pb, As and Zn levels are not important determinants of the neurodevelopment of 36- month-old children while a consistent beneficial effect of a stimulating home environment on neurodevelopmental indicators is continued.
authors: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan; International Institute for Child Rights and Development (IICRD), PO Box 8646 Victoria Main, Victoria, British Columbia, V8W 3S2, Canada; Basu Laboratory, CINE Building, Macdonald Campus, Faculty of Agricultural and Environmental Sciences, McGill University, Montreal, Quebec, Canada, H9X 3V9.
authors: Rajendra Prasad
authors: RP
authors: Parajuli
authors: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors: Masahiro
authors: M
authors: Umezaki
authors: Department of Social Medicine, National Research Institute for Child Health and Development, 2-10-1, Okura, Setagaya-ku, 157-8535 Tokyo, Japan.
authors: Takeo
authors: T
authors: Fujiwara
authors: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors: Chiho
authors: C
authors: Watanabe
mesh_terms: D001151:Arsenic / Q000097:blood* / Q000633:toxicity; D002657:Child Development / Q000187:drug effects; D002675:Child, Preschool; D003071:Cognition / Q000187:drug effects; D015331:Cohort Studies; D003943:Diagnostic Techniques, Neurological; D004785:Environmental Pollutants / Q000009:adverse effects / Q000097:blood*; D005195:Family Relations; D005260:Female; D005312:Fetal Blood / Q000737:chemistry; D006801:Humans; D007223:Infant; D007854:Lead / Q000097:blood* / Q000633:toxicity; D018811:Maternal Exposure / Q000009:adverse effects*; D009390:Nepal / Q000453:epidemiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000097:blood / Q000175:diagnosis*; D015032:Zinc / Q000097:blood* / Q000633:toxicity
chemical_list: D004785:Environmental Pollutants; D007854:Lead; D015032:Zinc; D001151:Arsenic