title: Blood mercury concentrations in CHARGE Study children with and without autism.
abstract: BACKGROUND
  Some authors have reported higher blood mercury (Hg) levels in persons with autism, relative to unaffected controls.
  
  
  OBJECTIVE
  We compared blood total Hg concentrations in children with autism or autism spectrum disorder (AU/ASD) and typically developing (TD) controls in population-based samples, and determined the role of fish consumption in differences observed.
  
  
  METHODS
  The Childhood Autism Risk from Genetics and the Environment (CHARGE) Study enrolled children 2-5 years of age. After diagnostic evaluation, we analyzed three groups: AU/ASD, non-AU/ASD with developmental delay (DD), and population-based TD controls. Mothers were interviewed about household, medical, and dietary exposures. Blood Hg was measured by inductively coupled plasma mass spectrometry. Multiple linear regression analysis was conducted (n = 452) to predict blood Hg from diagnostic status controlling for Hg sources.
  
  
  RESULTS
  Fish consumption strongly predicted total Hg concentration. AU/ASD children ate less fish. After adjustment for fish and other Hg sources, blood Hg levels in AU/ASD children were similar to those of TD children (p = 0.75); this was also true among non-fish eaters (p = 0.73). The direct effect of AU/ASD diagnosis on blood Hg not through the indirect pathway of altered fish consumption was a 12% reduction. DD children had lower blood Hg concentrations in all analyses. Dental amalgams in children with gum-chewing or teeth-grinding habits predicted higher levels.
  
  
  CONCLUSIONS
  After accounting for dietary and other differences in Hg exposures, total Hg in blood was neither elevated nor reduced in CHARGE Study preschoolers with AU/ASD compared with unaffected controls, and resembled those of nationally representative samples.
authors.affiliation: Department of Public Health Sciences, University of California-Davis, Davis, California 95616-8638, USA. ihp@ucdavis.edu
authors.forename: Irva
authors.initials: I
authors.lastname: Hertz-Picciotto
authors.forename: Peter G
authors.initials: PG
authors.lastname: Green
authors.forename: Lora
authors.initials: L
authors.lastname: Delwiche
authors.forename: Robin
authors.initials: R
authors.lastname: Hansen
authors.forename: Cheryl
authors.initials: C
authors.lastname: Walker
authors.forename: Isaac N
authors.initials: IN
authors.lastname: Pessah
mesh_terms: D000818:Animals; D001321:Autistic Disorder / Q000097:blood* / Q000209:etiology; D002140:California; D016022:Case-Control Studies; D002675:Child, Preschool; D002658:Developmental Disabilities / Q000097:blood / Q000209:etiology; D004781:Environmental Exposure; D005260:Female; D005399:Fishes; D005506:Food Contamination / Q000032:analysis; D006801:Humans; D008297:Male; D008628:Mercury / Q000097:blood*; D008954:Models, Biological; D018570:Risk Assessment
chemical_list: D008628:Mercury