T1-weighted brain magnetic resonance imaging (MRI) of the basal ganglia provides a noninvasive measure of manganese (Mn) exposure, and may also represent a biomarker for clinical neurotoxicity.
We acquired T1-weighted MRI scans in 27 Mn-exposed welders, 12 other Mn-exposed workers, and 29 nonexposed participants. T1-weighted intensity indices were calculated for four basal ganglia regions. Cumulative Mn exposure was estimated from work history data. Participants were examined using the Unified Parkinson's Disease Rating Scale motor subsection 3 (UPDRS3).
We observed a positive dose–response association between cumulative Mn exposure and the pallidal index (PI) (β = 2.33; 95% confidence interval [CI], 0.93 to 3.74). There was a positive relationship between the PI and UPDRS3 (β = 0.15; 95% CI, 0.03 to 0.27).
The T1-weighted pallidal signal is associated with occupational Mn exposure and severity of parkinsonism.
Department of Neurology, Washington University School of Medicine, St. Louis, Missouri (Dr Criswell, Dr Nielsen, Mr Warden, Mr Flores, Mr Lenox-Krug, Ms Racette, and Dr Racette); Department of Environmental and Occupational Health Sciences, University of Washington, School of Public Health, Seattle, Washington (Dr Sheppard); Department of Biostatistics, University of Washington, School of Public Health, Seattle, Washington (Dr Sheppard); Department of Family Medicine and Public Health, UC San Diego School of Medicine, La Jolla, California (Dr Checkoway); Department of Neurosciences, UC San Diego School of Medicine, La Jolla, California (Dr Checkoway); School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Parktown, South Africa (Dr Racette).
Address correspondence to: Susan R. Criswell, MD, MSCI, Washington University School of Medicine, 660 South Euclid Ave., Box 8111, St. Louis, MO 63110 (email@example.com).
This work was supported by the following National Institutes of Health grants: K23ES021444, R01ES021488, K24ES017765, P42ES004696, and R01ES013743.
Criswell, Nielsen, Warden, Flores, Lenox-Krug, Racette, Sheppard, Checkoway, and Racette have no relationships/conditions/circumstances that present potential conflict of interest.
The JOEM editorial board and planners have no financial interest related to this research.