International Meeting for Autism Research (London, May 15-17, 2008): The Tooth Fairy Project: Heavy Metal Concentrations in the “Baby Teeth” of Children with Autism Spectrum Disorders (ASD)

The Tooth Fairy Project: Heavy Metal Concentrations in the “Baby Teeth” of Children with Autism Spectrum Disorders (ASD)

Saturday, May 17, 2008
Champagne Terrace/Bordeaux (Novotel London West)
11:30 AM
M. M. Abdullah , Department of Psychology and Social Behavior, University of California, Irvine, Irvine, CA
A. R. Ly , Department of Psychology and Social Behavior, University of California, Irvine, Irvine, CA
W. A. Goldberg , Department of Psychology and Social Behavior, University of California, Irvine, Irvine, CA
K. A. Clarke-Stewart , Department of Psychology and Social Behavior, University of California, Irvine, Irvine, CA
T. Chan , Department of Environmental Health, Science and Policy, University of California, Irvine, Irvine, CA
E. Kent , Department of Environmental Health, Science and Policy, University of California, Irvine, Irvine, CA
J. Dudgeon , Department of Anthropology, California State University, Long Beach, Long Beach, CA
M. A. Spence , Pediatrics, University of California, Irvine, Irvine, CA
J. E. Ericson , Department of Environmental Health, Science and Policy, University of California, Irvine, Irvine, CA
Background:   The growing literature on exposure to heavy metals during sensitive periods of development is equivocal regarding the risk of neuropsychological disorders.  Recent reports have suggested mercury exposure as a potential contributor to the development of ASD (e.g., Bernard et al., 2002); others have not found an association (e.g., Fombonne et al., 2007).  Previous studies have been limited by the choice of biomarkers of blood, hair, and tooth dentin, which are redeveloping organic tissues that address only current levels of metals.  The current study focuses on tooth enamel, which does not regenerate, yielding archival records during two important periods:  prenatal and early postnatal brain development.
Objectives:   To evaluate differences in concentrations of heavy metals in shed deciduous teeth of children with ASD and matched typically developing children.
Methods:   Shed “baby teeth” were collected from 22 children with ASD and 22 typically developing children matched on gender (86% male) and chronological age (M = 11.7 years).  Study children were participants in one of two multi-site studies and received comprehensive developmental and psychological evaluations.  Trace metal spatial distributions of lead, mercury, manganese and other elements in tooth enamel were analyzed using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).  
Results:   Initial analyses do not indicate higher concentrations of lead, manganese, or mercury in either prenatal or postnatal regions of the teeth among children with ASD as compared to matched controls.  The presentation will include final analyses and interpretations on the full sample and on other elements.
Conclusions:   Based on preliminary results, concentrations of heavy metals do not seem to be higher in children with ASD. The type of biomarker used may be important, and it is also possible that prenatal and early postnatal exposure to heavy metals contributes to the development of ASD in some children, but not others.