Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 7, 2019; 25(33): 4885-4891
Published online Sep 7, 2019. doi: 10.3748/wjg.v25.i33.4885
Occupational exposure to vinyl chloride and liver diseases
Ugo Fedeli, Paolo Girardi, Giuseppe Mastrangelo
Ugo Fedeli, Paolo Girardi, Epidemiological Department, Azienda Zero, Padova 35131, Italy
Giuseppe Mastrangelo, Department of Cardiac, Thoracic and Vascular Sciences, University of Padova, Padova 35128, Italy
Author contributions: Fedeli U, Girardi P, Mastrangelo G reviewed the literature and wrote the manuscript.
Conflict-of-interest statement: All the Authors have no conflict of interest related to the manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Ugo Fedeli, MD, Senior Scientist, Epidemiological Department, Azienda Zero, Veneto Region, Passaggio Gaudenzio 1, Padova 35131, Italy.
Telephone: +39-49-8778542 Fax: +39-49-8778235
Received: March 26, 2019
Peer-review started: March 26, 2019
First decision: May 30, 2019
Revised: June 10, 2019
Accepted: June 25, 2019
Article in press: June 26, 2019
Published online: September 7, 2019

Portal hypertension, liver fibrosis, and angiosarcoma of the liver (ASL) have been reported among workers exposed to vinyl chloride monomer (VCM) since the 1970s. In 2007, the International Agency for Research on Cancer established the association of VCM with hepatocellular carcinoma (HCC), though only on the basis of the few cases available. Thereafter, recent reports from the United States cohort and a European sub-cohort of vinyl chloride workers provided compelling evidence of a strong association between cumulative VCM exposure and HCC risk. Further areas of research include the risk of liver cancer at lower levels of exposure and different patterns of risk of ASL and HCC with the time since exposure. The evidence of interaction between VCM exposure and other known liver carcinogens such as alcohol and chronic viral infection provides clues for the health surveillance of exposed workers. Notably, also the risk of VCM-associated chronic liver disease is modulated by alcohol consumption, viral infection, and genetic polymorphism. A counter-intuitive finding from cohort studies of exposed workers is the lower mortality from liver cirrhosis with respect to the general population; this can be attributed to the healthy worker effect and to the selection of liver cancer as the cause of death in the presence of concomitant chronic liver disease. Studies designed to overcome these intricacies confirmed an association between cumulative VCM exposure and the risk of liver cirrhosis.

Keywords: Vinyl chloride, Occupational exposure, Epidemiology, Liver cancer, Angiosarcoma, Hepatocellular carcinoma, Liver cirrhosis

Core tip: Occupational exposure to vinyl chloride monomer (VCM) causes chronic liver disease, liver angiosarcoma, and hepatocellular carcinoma. VCM exposure has a synergistic effect with other known risk factors of liver diseases such as alcohol consumption and chronic viral infection. Further research is warranted to assess the risk of liver cancer at low levels of exposure and to investigate the patterns of risk with time since exposure.