title: Cognitive function and plasma BDNF levels among manganese-exposed smelters.
abstract: OBJECTIVE
  To explore the potential dose-response relationship between manganese (Mn) exposure and cognitive function and also plasma brain-derived neurotrophic factor (BDNF) levels in occupational Mn exposure workers.
  
  
  METHODS
  A total 819 workers were identified from our Mn-exposed workers, and 293 control workers were recruited in the same region. All exposed workers were divided into three groups based on Mn cumulative exposure index. The Montreal Cognitive Assessment (MoCA) test was applied to estimate cognitive function for all subjects. Plasma BDNF levels were determined by ELISA in 248 selected exposed workers and 100 controls.
  
  
  RESULTS
  Mn-exposed workers had significantly lower MoCA scores than those in the control group (25.62 ± 0.25): those in high-exposure group had the lowest scores (21.33 ± 0.32), compared with the intermediate-exposure group (23.22 ± 0.30) and low-exposure group (23.57 ± 0.23). Mn exposure levels were inversely associated with MoCA total scores, all p<0.05. A positive correlation was found between plasma BDNF levels and MoCA total scores (r=0.278, p<0.01). Moreover, compared with the control group (288.7 ± 181.7 pg/mL), BDNF levels were lower in the high-exposure group (127.5 ± 99.8 pg/mL), and in the intermediate-exposure (178.2 ± 138.1 pg/mL) and low-exposure groups (223.4 ± 178.3 pg/mL). Additionally, plasma BDNF levels decreased significantly as Mn exposure levels increased (ptrend<0.01).
  
  
  CONCLUSIONS
  Mn exposure may be associated with decreased plasma BDNF levels and cognition impairment in this large cross-sectional study.
authors.affiliation: Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning, Guangxi, People's Republic of China.
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Zou
authors.forename: Li
authors.initials: L
authors.lastname: Qing
authors.forename: Xiaoyun
authors.initials: X
authors.lastname: Zeng
authors.forename: Yuefei
authors.initials: Y
authors.lastname: Shen
authors.forename: Yaoqiu
authors.initials: Y
authors.lastname: Zhong
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Qin
authors.initials: Q
authors.lastname: Li
authors.forename: Kangcheng
authors.initials: K
authors.lastname: Chen
authors.forename: Yingnan
authors.initials: Y
authors.lastname: Lv
authors.forename: Damin
authors.initials: D
authors.lastname: Huang
authors.forename: Guiqiang
authors.initials: G
authors.lastname: Liang
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Lang
authors.initials: L
authors.lastname: Chen
authors.forename: Yiping
authors.initials: Y
authors.lastname: Yang
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Yang
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000032:analysis; D019208:Brain-Derived Neurotrophic Factor / Q000097:blood*; D016022:Case-Control Studies; D003071:Cognition / Q000187:drug effects*; D003072:Cognition Disorders / Q000097:blood / Q000139:chemically induced*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007221:Industry; D019570:Inhalation Exposure / Q000009:adverse effects; D008297:Male; D008345:Manganese / Q000009:adverse effects*; D009784:Occupational Diseases / Q000097:blood / Q000139:chemically induced* / Q000523:psychology; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D009790:Occupations
chemical_list: D000395:Air Pollutants, Occupational; D019208:Brain-Derived Neurotrophic Factor; D008345:Manganese