You are here:
Manganese in Air: Associations in Residents with Tremor and Motor Function
Citation:
Bowler, R., C. Beseler, V. Gocheva, E. Kornblith, M. Colledge, Y. Kim, M. Lezak, C. Wright, AND D. Lobdell. Manganese in Air: Associations in Residents with Tremor and Motor Function. Presented at International Neuropsychological Society, Denver, CO, February 04 - 07, 2015.
Impact/Purpose:
This study addresses research questions under Sustainable and Healthy Communities (2.2.1.6 lessons learned, best practices and stakeholder feedback from community and tribal participative case studies). This Regional Applied Research Effort project is a joint effort between Region 5 and ORD Scientists that examined neurotoxic effects of Mn within two communities: a high level air exposure community (East Liverpool, Ohio) and a mid to low range air exposure community (Marietta, Ohio). This work is important in that either positive results (differences between the high level air Mn exposure community and comparison communities) or negative results (little or no differences among communities) inform the issue of potential health effects of residential airborne Mn exposure, a recognized gap in Mn health effects literature. Both outcomes can also help inform the need for greater airborne Mn control.
Description:
Objective: An environmental study examined air manganese (Mn) exposed residents of two towns in Ohio: Marietta (near a ferro-manganese smelter) and East Liverpool (EL)(adjacent to an open-storage ore packaging facility). Air Mn inhalation is associated with neuropsychological/neurological sequelae. Positive relationships between air Mn and neuropsychological/neurological dysfunction were hypothesized. Participant and Methods: AERMOD dispersion modeling and ten years of fixed-site outdoor air monitoring data were used to estimate air Mn inhalation exposures. Motor tests of Finger Tapping, Hand Dynamometer, Grooved Pegboard, and CATSYS Tremor were administered bilaterally to 186 adult Mn-exposed residents (Marietta: n=100; East Liverpool: n= 86). Bayesian modeling was used to assess associations between tremor and motor function and air Mn. Results: Air Mn exposure was significantly correlated with CATSYS hand tremor intensity (p=0.02), center frequency (p<0.0001) and harmonic index (p<0.0001) in bivariate analyses. Center frequency (β=1.04, p<0.0001) and harmonic index (β=-0.08, p<0.0001) left hand showed strong and significant associations with air Mn in a Bayesian path analysis model. This model was significantly associated with lower Finger Tapping dominant (rs=-0.26, p<0.001) and non-dominant (rs=-0.16, p=0.03) hand T scores. Exposure to other metals (Pd, Cd, Hg and Fe) did not explain these results. Household income was significantly associated with motor dysfunction but not with tremor. Conclusions: Tremor and motor function were negatively associated with higher exposure to airborne Mn. Tremor scores showed stronger associations in the Bayesian model than the motor function scores. This may be due to the higher prevalence of subtle effects of long-term Mn exposure.Disclaimer: This abstract does not necessarily reflect EPA or ATSDR policy.