Co-exposure to manganese and lead and pediatric neurocognition in East Liverpool, Ohio

Kaitlin Vollet Martin; Heidi Sucharew; Kim N Dietrich; Patrick J Parsons; Christopher D Palmer; Robert Wright; Chitra Amarasiriwardena; Donald R Smith; Erin N Haynes

doi:10.1016/j.envres.2021.111644

Co-exposure to manganese and lead and pediatric neurocognition in East Liverpool, Ohio

Environ Res. 2021 Nov:202:111644. doi: 10.1016/j.envres.2021.111644. Epub 2021 Jul 8.

Authors

Kaitlin Vollet Martin¹, Heidi Sucharew², Kim N Dietrich³, Patrick J Parsons⁴, Christopher D Palmer⁴, Robert Wright⁵, Chitra Amarasiriwardena⁵, Donald R Smith⁶, Erin N Haynes⁷

Affiliations

¹ Department of Epidemiology, College of Public Health, University of Kentucky, Lexington, KY, USA. Electronic address: kaitlin.vollet.martin@uky.edu.
² Division of Biostatistics and Epidemiology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
³ Department of Environmental Health, College of Medicine, University of Cincinnati, Cincinnati, OH, USA.
⁴ Wadsworth Center, New York State Department of Health, Albany, NY, USA; Department of Environmental Health Sciences, School of Public Health, University of Albany, Rensselaer, NY, USA.
⁵ Icahn School of Medicine at Mount Sinai, New York, USA.
⁶ Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA, USA.
⁷ Department of Epidemiology, College of Public Health, University of Kentucky, Lexington, KY, USA.

Abstract

Exposure to metal mixtures may lead to health impacts greater than the effects associated with singular exposures. Two common childhood environmental exposures, manganese (Mn) and lead (Pb), are associated with similar adverse neurodevelopmental effects; however, the effects surrounding concurrent exposure to both metals remain unclear. We study the impact of joint exposure to Mn and Pb on cognitive performance in school-aged children participating in the Communities Actively Researching Exposure Study (CARES) based in East Liverpool, Ohio. Blood Pb levels were measured for each child (geometric mean (GM) = 1.13 μg/dL, range 0.30 μg/dL - 6.64 μg/dL). Mn was measured in participant blood, hair, and toenails with GMs of 10.1 μg/L, 360 ng/g, 0.974 μg/g, respectively. Trained team members administered the Wechsler Intelligence Scale for Children-IV (WISC-IV) to assess intelligence quotient (IQ). The WISC-IV provides scores for Full Scale IQ, Perceptual Reasoning, Processing Speed, Working Memory, and Verbal Comprehension. Interactions between blood Pb and all Mn biomarkers were tested in linear models adjusted for child sex, household income, and serum cotinine. Separate regression models were run for each of the Mn biomarkers. The cohort was comprised of 106 children with a mean age of 8.4 years. Interactions between blood Pb and hair Mn were significant (p < 0.05) for four out of the five IQ domains. The effect of blood Pb on IQ was more pronounced at higher levels of hair and toenail Mn. No significant associations were observed when characterizing the main effect of Mn using blood. Uncovering the health impacts associated with exposure mixtures is critical to understanding the impact of real-life conditions. Our findings suggest that joint exposure to Mn and Pb may produce heightened neurocognitive impacts even at blood Pb levels below the CDC reference concentration of 5 μg/dL.

Keywords: Lead; Manganese; Metal mixtures; Neurocognition; Pediatric environmental health.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Child
Environmental Exposure / analysis
Environmental Exposure / statistics & numerical data
Humans
Intelligence Tests
Lead* / toxicity
Manganese* / toxicity
Ohio

Substances

Lead
Manganese

Abstract

Publication types

MeSH terms

Substances

Grants and funding