title: Pallidal index on MRI as a target organ dose of manganese: structural equation model analysis.
abstract: We have used a structural equation model (SEM) to analyze the interrelationships among exposure markers, magnetic resonance imaging (MRI) signal index, and neurobehavioral effects. Based on exposure groups, we assessed blood manganese, MRI measurements of pallidal index (PI), and neurobehavioral core test battery (WHO-NCTB) on 111 male workers occupationally exposed to manganese, including welders, smelter workers, and welding rod manufacturing workers. Latent variables were constructed to represent the neurobehavioral effects in an integrated way. The structural equation model revealed that airborne manganese and blood manganese contribute to PI significantly. Manganese exposure in the ambient air may lead to an increase in the internal dose, not only indirectly, by increasing blood manganese level, but also directly, independent of blood concentration. PI significantly contributed to a decrease in neurobehavioral test scores. We found that airborne manganese contributed to PI, and that PI is the most effective predictor of neurobehavioral performance, after adjusting for age and level of education. In conclusion, PI on MRI reflects target organ dose of occupational manganese exposure.
authors.affiliation: Occupational Safety and Health Research Institute, Korea Occupational Safety and Health Agency, Incheon, Republic of Korea.
authors.forename: Euna
authors.initials: E
authors.lastname: Kim
authors.forename: Yangho
authors.initials: Y
authors.lastname: Kim
authors.forename: Hae-Kwan
authors.initials: HK
authors.lastname: Cheong
authors.forename: Sungil
authors.initials: S
authors.lastname: Cho
authors.forename: Yong Chul
authors.initials: YC
authors.lastname: Shin
authors.forename: Joon
authors.initials: J
authors.lastname: Sakong
authors.forename: Kyoo Sang
authors.initials: KS
authors.lastname: Kim
authors.forename: Jung Sun
authors.initials: JS
authors.lastname: Yang
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Jin
authors.forename: Seong-Kyu
authors.initials: SK
authors.lastname: Kang
mesh_terms: D000062:Accidents, Occupational / Q000706:statistics & numerical data; D000328:Adult; D000339:Affect / Q000187:drug effects; D001288:Attention / Q000187:drug effects; D001519:Behavior / Q000187:drug effects; D003430:Cross-Sectional Studies; D005917:Globus Pallidus / Q000473:pathology*; D006801:Humans; D019570:Inhalation Exposure; D008279:Magnetic Resonance Imaging; D008297:Male; D008345:Manganese / Q000032:analysis / Q000097:blood; D020149:Manganese Poisoning / Q000473:pathology* / Q000523:psychology; D008568:Memory / Q000187:drug effects; D008875:Middle Aged; D009483:Neuropsychological Tests; D016273:Occupational Exposure / Q000009:adverse effects*; D011597:Psychomotor Performance / Q000187:drug effects; D012044:Regression Analysis; D012959:Socioeconomic Factors
chemical_list: D008345:Manganese