Manganese burden of deciduous teeth and childhood behavioral deficits

Attention Deficit/Hyperactivity Disorder (ADHD) affects 5--8% of children and 4--8% of adults in the U.S. The contributions of metals exposure to the behavioral deficits observed in children is unclear although particular metals have been implicated through their neurotoxic effects. The objective of this study is to test the hypothesis that the body burden of Mn is positively correlated with ADHD symptoms. We also investigated the putative roles of Ca, Fe, Pb, and Hg.;Shed molars were collected from 266 children (138 boys and 128 girls) who lost a tooth between 11 and 13 years of age. All subjects are participants of a national NICHD Study. The molars were analyzed for metals using ICP-OES. Teacher's Disruptive Behavior Disorders Rating Scale (DBD) was completed by the third grade teacher of each child, producing a score for Total Disruptive Behavior and subscale scores for ADHD, Hyperactivity/Impulsivity, Inattention, and Oppositional/Defiant.;The mean Mn, Fe, Pb and Ca concentrations found in teeth was 6.1 +/- 5.7 microg/g, 22.7 +/- 24.1 microg/g, 0.9 +/- 1.4 microg/g, and 6 x 105 +/- 1.6 x 105 microg/g respectively. Hg was not detected in the tooth samples. Ca showed a significant negative association with the behavioral measurements and Pb showed a significant positive association with Hyperactivity/Impulsivity, Inattention, and Oppositional/Defiant Disorders.;These findings call into question the putative independent association of manganese exposure and behavioral deficits in children, when the balance of other metallic burden, particularly Ca and Pb may play a role.