Evaluation of liver enzyme levels in workers exposed to vinyl chloride vapors in a petrochemical complex: a cross-sectional study

BACKGROUND: Polyvinyl chloride is used in production and manufacturing of many essential tools (e.g. plastic pipes, photography films, etc.). Its production is impossible without the use of vinyl chloride monomer (VCM), which can cause liver damage in long-term. In this study we intend to assess the effects of mild to moderate long term exposure to VCM on liver and to assess the importance of liver enzyme measurements as a screening tool. METHODS: In this study, liver enzyme levels of 52 workers were compared to 48 control workers using the T-test. The cases all worked in a PVC production unit in a petrochemical complex and the controls were randomly selected from office personnel of the same complex. A questionnaire was also filled in about information such as age, weight, work history, etc. in both groups. RESULTS: Mean comparisons for ALP and GGT using T-test showed statistically significant differences between the two groups. For AST, ALT and bilirubin (total, direct) the mean was higher in the case group but this difference was not statistically significant. DISCUSSION: This study showed that mild exposure to VCM can cause mild liver cholestasis. So, using cholestasis assessment tests such as ALP and GGT should be considered in periodic assessment of liver function in PVC producing units.