MANGANESE EXPOSURE AND NEURODEVELOPMENT AMONG ITALIAN ADOLESCENTS RESIDING NEAR FERRO-ALLOY INDUSTRY

摘要

Introduction: Growing epidemiologic evidence suggests that environmental exposure of children to manganese (Mn) is associated with decrements in neurobehavior. However, substantial gaps remain in our understanding of Mn health risks among adolescents and in relation to developmental timing of exposure, child sex, and varying biomarkers of exposure. Methods: As part of the Public Health Impact of Manganese Exposure (PHIME) study, we measured Mn concentrations in blood, hair, nails, saliva, and urine collected from 11-14 year old Italian children (N-720) living near ferromanganese industry. Mn levels were also measured in deciduous teeth to represent prenatal, postnatal, and cumulative early childhood exposure periods. Neurobehavioral assessments, conducted concurrent with biological sample collection, included the Wechsler Intelligence Scale for Children, Conners Behavior Rating Scale, Virtual Radial Arm Maze, and California Verbal Learning Test. Multivariable models were used to evaluate associations between Mn and neurobehavior. Results: We observed inverse associations between childhood Mn with cognition (e.g., saliva and verbal IQ, β=-1.4, p=0.004) and memory (e.g., saliva and short recall, B=-0.3, p=0.001). In contrast, early life Mn (teeth) was associated with improved scores of cognition (e.g., digit span backward, β=0.4, p=0.05), behavior (e.g., teacher-reported inattention, p=-0.07, p=0.04), and memory (e.g., sum of intrusions, β=-1.8, p=0.03). We also observed sex-specific associations: a U-shaped association was seen only among girls for prenatal Mn and visual learning (p_(GAM)=0.009-0.02). Conclusions: These results suggest a complex relationship between Mn and neurobehavior, whereby associations may differ by timing of exposure and sex.