title: Interaction of occupational manganese exposure and alcohol drinking aggravates the increase of liver enzyme concentrations from a cross-sectional study in China.
abstract: BACKGROUND
  Over exposure to manganese (Mn) can damage the human central nervous system and potentially cause liver toxicity. Alcohol drinking is also one of the well-known harmful factors to hepatic organism. The interaction between Mn exposure and alcohol consumption to liver function was investigated in this study.
  
  
  METHODS
  A total of 1112 on-the-spot workers were included in the cross-sectional survey from a large scale of manganese exposed workers healthy cohort (MEWHC) in a ferro-manganese refinery company. A questionnaire was used to collect the demographic information, occupational history, and alcohol drinking habits. Occupational health examination was carried out for each worker. The five key serum indices, including total bilirubin (TBILI), direct bilirubin (DBILI), indirect bilirubin (IBILI), alanine transaminase (ALT), and aspartate transaminase (AST), were determined to evaluate the liver function of each subject.
  
  
  RESULTS
  Workers exposed to high levels of Mn had significantly elevated serum concentrations of liver enzymes (DBILI: 3.84±1.20 μmol/L, ALT: 27.04±19.12 IU/L, and AST: 29.96±16.68 IU/L), when compared to those in the low-exposure group (DBIL: 3.54±0.85 μmol/L, ALT: 20.38±10.97 IU/L, and AST: 26.39±8.07 IU/L), all P<0.01. These serum indices had a significantly increasing trend with the elevation of Mn exposure level (Ptrend <0.01). In addition, the workers with alcohol drinking also showed higher concentrations of liver enzymes than those non-drinkers, especially, and there was significant interaction between Mn exposure and alcohol consumption in terms of these three indices (P<0.001).
  
  
  CONCLUSIONS
  Occupational exposure to Mn can lead to a dose-dependent increase of liver enzyme concentrations, and interact with alcohol drinking to potentially aggravate the liver damage. It will be important for Mn exposed workers to control drinking and also assess liver function in the occupational health examination.
authors.affiliation: Department of occupational health and environmental health, School of Public Health, Guangxi Medical University, Guangxi, Nanning, China. email_zyf@163.com
authors.forename: Qi
authors.initials: Q
authors.lastname: Deng
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Kangcheng
authors.initials: K
authors.lastname: Chen
authors.forename: Zhenfang
authors.initials: Z
authors.lastname: Liu
authors.forename: Yuefei
authors.initials: Y
authors.lastname: Shen
authors.forename: Piye
authors.initials: P
authors.lastname: Niu
authors.forename: Yiping
authors.initials: Y
authors.lastname: Yang
authors.forename: Yunfeng
authors.initials: Y
authors.lastname: Zou
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Yang
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D001774:Blood Chemical Analysis; D002681:China; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D004784:Environmental Monitoring; D000431:Ethanol / Q000378:metabolism / Q000633:toxicity*; D005260:Female; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008345:Manganese / Q000032:analysis / Q000633:toxicity*; D008669:Metallurgy; D016273:Occupational Exposure; D011446:Prospective Studies; D013054:Spectrophotometry, Atomic; D011795:Surveys and Questionnaires
chemical_list: D015415:Biomarkers; D000431:Ethanol; D008345:Manganese