title: Manganese in teeth and neurodevelopment in young Mexican-American children.
abstract: BACKGROUND
  Manganese (Mn) is an essential nutrient but higher exposure has been associated with poorer neurodevelopment in children.
  
  
  METHODS
  We measured Mn levels in prenatal (Mnpre) (n=197) and postnatal (Mnpost) dentin (n=193) from children's shed teeth using laser ablation inductively coupled plasma mass spectroscopy and examined the relationship with children's scores on the Mental Development Index (MDI) and Psychomotor Development Index (PDI) on the Bayley Scales of Infant Development at 6, 12, and 24-months. We explored non-linear associations and interactions by sex, blood lead concentrations and maternal iron status during pregnancy.
  
  
  RESULTS
  A two-fold increase of Mnpost levels in dentin was associated with small decreases in MDI at 6-months and 12-months of age. We also observed a non-linear relationship between Mnpost levels and PDI at 6-months. We found effect modification by sex for Mnpost levels and neurodevelopment at 6-months with stronger effects among girls for both MDI (-1.5 points; 95% Confidence Interval (CI): -2.4, -0.6) and PDI (-1.8 points; 95% CI: -3.3, -0.3). Girls whose mothers had lower hemoglobin levels experienced larger decreases in MDI and PDI associated with Mnpre levels than girls whose mothers had higher hemoglobin levels (pinteraction=0.007 and 0.09, respectively). We did not observe interactions with blood lead concentrations or any relationships with neurodevelopment at 24-months.
  
  
  CONCLUSIONS
  Using Mn measurements in tooth dentin, a novel biomarker that provides prenatal and early postnatal levels, we observed negative transient associations between postnatal Mn levels and early neurodevelopment with effect modification by sex and interactions with prenatal hemoglobin.
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Robert B
authors.initials: RB
authors.lastname: Gunier
authors.affiliation: Exposure Biology, Lautenberg Environmental Health Sciences Laboratory, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA; Faculty of Dentistry, University of Sydney, 2 Chalmers Street, Surry Hills, Sydney, NSW 2010, Australia.
authors.forename: Manish
authors.initials: M
authors.lastname: Arora
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Jerrett
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Asa
authors.initials: A
authors.lastname: Bradman
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Kim G
authors.initials: KG
authors.lastname: Harley
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA; Central American Institute for Studies on Toxic Substances (IRET), Universidad Nacional, P.O. Box 86-3000, Heredia, Costa Rica.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Mora
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Kogut
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Alan
authors.initials: A
authors.lastname: Hubbard
authors.affiliation: Exposure Biology, Lautenberg Environmental Health Sciences Laboratory, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, New York, NY 10029, USA; Faculty of Dentistry, University of Sydney, 2 Chalmers Street, Surry Hills, Sydney, NSW 2010, Australia.
authors.forename: Christine
authors.initials: C
authors.lastname: Austin
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA.
authors.forename: Nina
authors.initials: N
authors.lastname: Holland
authors.affiliation: Center for Environmental Research and Children's Health (CERCH), School of Public Health, University of California, 1995 University Avenue, Suite 265, Berkeley, CA 94707, USA. Electronic address: eskenazi@berkeley.edu.
authors.forename: Brenda
authors.initials: B
authors.lastname: Eskenazi
mesh_terms: D000293:Adolescent; D000328:Adult; D002657:Child Development; D005260:Female; D006801:Humans; D007223:Infant; D008345:Manganese / Q000032:analysis* / Q000633:toxicity; D017058:Mexican Americans; D008875:Middle Aged; D009420:Nervous System / Q000254:growth & development*; D014070:Tooth / Q000737:chemistry*; D055815:Young Adult
chemical_list: D008345:Manganese
keywords: Bayley Scales of Infant Development; Manganese; Neurodevelopment; Pesticides