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Neuromotor Effects of Manganese Exposure in Adolescents

McBride, Danielle
http://orcid.org/0000-0003-2965-6444
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1637055651732617

Abstract Details

2021, PhD, University of Cincinnati, Medicine: Epidemiology (Environmental Health).
Background: Manganese (Mn) toxicity is most often a result of industrial point sources, as Mn compounds are emitted from metal processing factories. Environmental Mn exposure has been linked to deficits in neuromotor function. Marietta, Ohio is home to the longest operating ferromanganese refinery, the top source of ambient Mn in North America. In this community-based longitudinal cohort study of children living near the refinery, we investigate the relationship between childhood and adolescent exposure to Mn and adolescent neuromotor function. Methods: A literature review was conducted to evaluate the current body of knowledge surrounding pediatric Mn exposure and neuromotor function. Participants in the Communities Actively Researching Exposures Study (CARES) provided biological specimens of blood, hair and toenails at a childhood visit conducted at ages 7-9 years. Blood was analyzed for manganese (Mn), lead (Pb) and serum cotinine, a marker of environmental tobacco smoke. Hair and toenails were analyzed for Mn. Study participants returned during adolescent years 13-17 for collection of biological specimens of blood and hair and evaluation of neuromotor function through postural balance testing. Blood was analyzed for Mn, Pb and serum cotinine and hair for Mn. Geometric means (GM) and geometric standard deviations (GSD) were calculated for biomarker concentrations and arithmetic means and standard deviations (SD) and frequencies for sociodemographic information of participants. Multivariable regression models were employed to examine the relationships between childhood and adolescent Mn exposure and adolescent postural balance, adjusting for covariates. Secondary analyses were conducted to visually examine plots with fitted splines and gender-by-Mn interaction effects on postural balance. Results: The CARES participants who completed adolescent postural balance testing were 54% female and 98% Caucasian. The mean age was 16 years old (range 13-17). Biomarkers of Mn exposure collected in childhood and adolescence are presented GM (range): childhood blood Mn: 9.74 µg/L (5.3-18.8); adolescent blood Mn: 9.95 µg/L (5-30); childhood hair Mn: 408.08 ng/g (63.19-7,379.09; adolescent hair Mn: 189.18 ng/g (29.9-3,330); childhood toenail Mn: 0.65 µg/g (0.06-9.66). After adjusting for covariates, hair Mn was consistently associated with increased sway area (ß=0.16, 95% CI: 0.05, 0.26), medial-lateral sway (ß=0.07, 95% CI: 0.002, 0.15) and anterior-posterior sway (ß=0.08, 95% CI: 0.02, 0.14) for the test condition Eyes Open on Foam. For a number of test conditions, childhood Mn was associated with better body stability in boys only. During adolescence, higher concurrent blood Mn was significantly associated with increased sway area for test conditions Eyes Open (ß=0.46, 95% CI: 0.07, 0.84) and Eyes Closed (ß=0.45, 95% CI: 0.05, 0.86). Secondary analyses did not reveal the presence of non-linear associations between Mn exposure in childhood and adolescence and postural balance in adolescence. Conclusion: Findings from this study suggest childhood Mn exposure may manifest subclinical developmental neurotoxicity during adolescence as impaired motor function, with specific gender effects. Further evidence supports the subclinical neurotoxicity of adolescent Mn exposure on concurrent postural instability. This study has implications for Mn-exposed children as a vulnerable population for increased risk of occupational slips, trips, and falls as they age into the labor force.
Amit Bhattacharya, Ph.D. (Committee Chair)
Heidi Sucharew (Committee Member)
Erin Haynes, Dr.P.H. (Committee Member)
Kelly Brunst, Ph.D. (Committee Chair)
169 p.
Epidemiology
Manganese; Environmental Health; Pediatric Neurodevelopment; Motor function; Exposure Science; Marietta

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Citations

  • McBride, D. (2021). Neuromotor Effects of Manganese Exposure in Adolescents [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1637055651732617

    APA Style (7th edition)

  • McBride, Danielle. Neuromotor Effects of Manganese Exposure in Adolescents. 2021. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1637055651732617.

    MLA Style (8th edition)

  • McBride, Danielle. "Neuromotor Effects of Manganese Exposure in Adolescents." Doctoral dissertation, University of Cincinnati, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1637055651732617

    Chicago Manual of Style (17th edition)

ucin1637055651732617
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