title: Home environment and cord blood levels of lead, arsenic, and zinc on neurodevelopment of 24 months children living in Chitwan Valley, Nepal.
abstract: In a birth cohort living in Chitwan Valley, lowland Nepal, we have previously reported inverse associations between in utero levels of lead (Pb), arsenic (As) and neurodevelopment at birth measured by the Brazelton Neonatal Behavioral Assessment Scale, third edition (NBAS III). In the present paper, a follow-up of the same cohort was made on 24-month-old infants regarding the neurodevelopmental effects of these metals, taking the postnatal environment into account. In total, the same100 mother-infant pairs as the previous study, whose Pb, As, and Zn concentrations in cord blood were known, were recruited. Postnatal raising environment was evaluated using the Home Observation for Measurement of Environment (HOME) scale. Neurodevelopment of children at 24 months of age (n=74) was assessed using 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. Unlike the NBAS III conducted for newborns, none of the BSID II cluster scores in 24-month-old infants were associated with cord blood levels of Pb, As, and Zn. The total HOME score was positively associated with the mental development scale (MDI) score (coefficient=0.67, at 95% CI=0.03 to 1.31). In this cohort, a detrimental effect of in utero Pb and As on neurodevelopmental indicators observed at birth disappeared at 24 months, while an association between neurodevelopment and home environment continued.
authors.affiliation: 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, BC, Canada V8W 3S2. Electronic address: parajulirp@humeco.m.u-tokyo.ac.jp.
authors.forename: Rajendra Prasad
authors.initials: RP
authors.lastname: Parajuli
authors.affiliation: Department of Social Medicine, National Research Institute for Child Health and Development, 2-10-1, Okura, Setagaya-ku, 157-8535 Tokyo, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Fujiwara
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Umezaki
authors.affiliation: Department of Human Ecology, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Chiho
authors.initials: C
authors.lastname: Watanabe
mesh_terms: D001151:Arsenic / Q000097:blood*; D002657:Child Development; D002675:Child, Preschool; D003710:Demography; D004777:Environment; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D007854:Lead / Q000097:blood*; D008297:Male; D009390:Nepal; D009420:Nervous System / Q000254:growth & development*; D055815:Young Adult; D015032:Zinc / Q000097:blood*
chemical_list: D007854:Lead; D015032:Zinc; D001151:Arsenic
keywords: Bayley scale; HOME scale; Nepal; Neurodevelopment; Toxic and essential elements