Severity of parkinsonism associated with environmental manganese exposure

Authors

Brad A. Racette, Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8111, 63110, St. Louis, Missouri, USA. racetteb@wustl.edu.
Gill Nelson, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, 2193, Parktown, South Africa.
Wendy W. Dlamini, Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8111, 63110, St. Louis, Missouri, USA.
Pradeep Prathibha, Department of Energy, Environmental, and Chemical Engineering, Washington University, Campus Box 1180, One Brookings Drive, 63130, St. Louis, Missouri, USA.
Jay R. Turner, Department of Energy, Environmental, and Chemical Engineering, Washington University, Campus Box 1180, One Brookings Drive, 63130, St. Louis, Missouri, USA.
Mwiza Ushe, Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8111, 63110, St. Louis, Missouri, USA.
Harvey Checkoway, Department of Family Medicine & Public Health, University of California, 9500 Gilman Drive, # 0725, La Jolla, 92093-0725, San Diego, California, USA.
Lianne Sheppard, Departments of Biostatistics and Environmental and Occupational Health Sciences, University of Washington, Box 357232, Washington,, 98195, Seattle, USA.
Susan Searles Nielsen, Department of Neurology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8111, 63110, St. Louis, Missouri, USA.

Document Type

Article

Abstract

BACKGROUND: Exposure to occupational manganese (Mn) is associated with neurotoxic brain injury, manifesting primarily as parkinsonism. The association between environmental Mn exposure and parkinsonism is unclear. To characterize the association between environmental Mn exposure and parkinsonism, we performed population-based sampling of residents older than 40 in Meyerton, South Africa (N = 621) in residential settlements adjacent to a large Mn smelter and in a comparable non-exposed settlement in Ethembalethu, South Africa (N = 95) in 2016-2020. METHODS: A movement disorders specialist examined all participants using the Unified Parkinson Disease Rating Scale motor subsection part 3 (UPDRS3). Participants also completed an accelerometry-based kinematic test and a grooved pegboard test. We compared performance on the UPDRS3, grooved pegboard, and the accelerometry-based kinematic test between the settlements using linear regression, adjusting for covariates. We also measured airborne PM-Mn in the study settlements. RESULTS: Mean PM-Mn concentration at a long-term fixed site in Meyerton was 203 ng/m in 2016-2017 - approximately double that measured at two other neighborhoods in Meyerton. The mean Mn concentration in Ethembalethu was ~ 20 times lower than that of the long-term Meyerton site. UPDRS3 scores were 6.6 (CI 5.2, 7.9) points higher in Meyerton than Ethembalethu residents. Mean angular velocity for finger-tapping on the accelerometry-based kinematic test was slower in Meyerton than Ethembalethu residents [dominant hand 74.9 (CI 48.7, 101.2) and non-dominant hand 82.6 (CI 55.2, 110.1) degrees/second slower]. Similarly, Meyerton residents took longer to complete the grooved pegboard, especially for the non-dominant hand (6.9, CI -2.6, 16.3 s longer). CONCLUSIONS: Environmental airborne Mn exposures at levels substantially lower than current occupational exposure thresholds in the United States may be associated with clinical parkinsonism.

Medical Subject Headings

Accelerometry; Adolescent; Adult; Aged; Air Pollutants, Occupational (analysis, toxicity); Biomechanical Phenomena; Child; Child, Preschool; Environmental Exposure (adverse effects, analysis); Female; Humans; Infant; Infant, Newborn; Male; Manganese (analysis, toxicity); Mental Status and Dementia Tests; Metallurgy; Middle Aged; Parkinsonian Disorders (chemically induced, physiopathology); Particulate Matter (analysis, toxicity); South Africa; Young Adult

Publication Date

3-15-2021

Publication Title

Environmental health : a global access science source

E-ISSN

1476-069X

Volume

20

Issue

1

First Page

27

PubMed ID

33722243

Digital Object Identifier (DOI)

10.1186/s12940-021-00712-3

Recommended Citation

Racette, Brad A.; Nelson, Gill; Dlamini, Wendy W.; Prathibha, Pradeep; Turner, Jay R.; Ushe, Mwiza; Checkoway, Harvey; Sheppard, Lianne; and Nielsen, Susan Searles, "Severity of parkinsonism associated with environmental manganese exposure" (2021). Neurology. 1180.
https://scholar.barrowneuro.org/neurology/1180