title: Vitamin B12 and folate deficiency and elevated plasma total homocysteine in workers with chronic exposure to chromate.
abstract: OBJECTIVE
  Chronic occupational exposure to chromium can result in a broad range of adverse effects including multiple organ damage, genotoxicity and carcinogenesis. However, the metabolic consequences of chromium exposure have not been fully investigated. This study was designed to examine vitamin B12, folate and homocysteine metabolic changes in workers chronically exposed to chromate. The potential association between metabolic alteration and renal impairment induced by chromate exposure was also assessed.
  
  
  METHODS
  The level of chromium exposure was evaluated by measuring chromium concentrations in red blood cells (RBC-Cr) and urine (U-Cr). Renal impairment was assessed with serum cystatin C (Cys-C) and urinary β2-microglobulin (β2M). Serum vitamin B(12), folate and plasma total homocysteine (tHcy) were measured and correlations analysed.
  
  
  RESULTS
  Significant increases in RBC-Cr, U-Cr, serum Cys-C, plasma tHcy and urinary β2M concentrations were observed in workers chronically exposed to chromate compared to controls. In the exposed workers, serum vitamin B12 and folate levels were decreased and significantly inversely correlated with RBC-Cr concentrations, and increased plasma tHcy concentrations were mirrored by decreased serum vitamin B12 and folate levels. Elevated plasma tHcy concentrations were positively related to serum Cys-C concentrations.
  
  
  CONCLUSIONS
  Hyperhomocysteinemia in chronically exposed workers was primarily induced by vitamin B12 and folate deficiency. This metabolic change might be associated with renal dysfunction in chromate processing workers after long term exposure.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Health Science Center of Peking University, Beijing 100191, PR China.
authors.forename: Tian-Cheng
authors.initials: TC
authors.lastname: Wang
authors.forename: Guang
authors.initials: G
authors.lastname: Jia
authors.forename: Ji
authors.initials: J
authors.lastname: Zhang
authors.forename: Yan-Hui
authors.initials: YH
authors.lastname: Ma
authors.forename: Lan-Zheng
authors.initials: LZ
authors.lastname: Liu
authors.forename: Ning
authors.initials: N
authors.lastname: Zhang
authors.forename: Wei-Yue
authors.initials: WY
authors.lastname: Feng
authors.forename: Jing-Wen
authors.initials: JW
authors.lastname: Zhou
authors.forename: Yan-Shuang
authors.initials: YS
authors.lastname: Song
authors.forename: Lei
authors.initials: L
authors.lastname: Yan
authors.forename: Xian-Mei
authors.initials: XM
authors.lastname: Du
mesh_terms: D000328:Adult; D002681:China / Q000453:epidemiology; D002840:Chromates / Q000378:metabolism / Q000633:toxicity*; D005260:Female; D005492:Folic Acid / Q000097:blood; D005494:Folic Acid Deficiency / Q000097:blood / Q000453:epidemiology*; D006710:Homocysteine / Q000097:blood; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood / Q000453:epidemiology*; D016273:Occupational Exposure / Q000009:adverse effects*; D014805:Vitamin B 12 / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D002840:Chromates; D006710:Homocysteine; D005492:Folic Acid; D014805:Vitamin B 12