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.

Researchers reach contradictory results when trying to assess the potential harm of e-cigarettes. This study investigated whether the findings and conclusions in papers published on e-cigarettes and health differ depending on whether the authors had a financial conflict of interest (COI) or not. A total of 94 studies (identified in a previous systematic review) that investigated the content of fluid/vapor of e-cigarettes or in vitro experiments were included. The type, level and direction of the financial COI were coded. Abstracts were blinded and evaluated by two assessors. Fischer's Test and Logistic regression analyses were used to investigate the associations between findings of harm/conclusions and COI. All three dimensions of COI showed the same tendency: studies with industry-related COI found potential harm significantly less often than studies without a COI. 95.1% of papers without and 39.4% of papers with a COI found potential harmful effects/substances. Only 7.7% of tobacco industry-related studies found potential harm. The odds of finding of no harm were significantly higher in studies with an industry-related COI (OR 66.92 (95% CI 8.1-552.9)) than in studies without a COI. A strong/moderate COI was associated with very high odds (OR 91.50 (95% CI 10.9-771.4)) of finding of no harm compared with studies with no/weak COI. This blinded assessment showed that almost all papers without a COI found potentially harmful effects of e-cigarettes. There was a strong association between industry-related COI and tobacco- and e-cigarette industry-favourable results, indicating that e-cigarettes are harmless.

Occupational exposure to vinyl chloride monomer (VCM) has been established as a cause of hepatocellular carcinoma (HCC) and liver angiosarcoma (ASL). However, some controversy remains due to conflicting results on liver cirrhosis, and to evidence on HCC based on few confirmed cases. The aim of the study is to clarify the association between VCM exposure and mortality from liver diseases.

In a cohort of 1658 workers involved in VCM production and polymerization, Poisson regression was adopted to estimate rate ratios (RR) across categories of VCM exposure for mortality due to ASL (n = 9), HCC (n = 31) confirmed by histological/clinical records, and the combination of deaths from liver cirrhosis and from liver cancer with clinical/histological evidence of cirrhosis (n = 63).

Cumulative VCM exposure was associated with study outcomes; RRs in the highest compared to the lowest exposure category were: ASL 91.1 (95%Confidence Interval 16.8-497), HCC 5.52 (2.03-15.0), liver cirrhosis 2.60 (1.19-5.67).

The risk of death from liver cirrhosis, as well as from HCC in the largest available series of confirmed cases, increased with VCM exposure.

Liver cancer is the second leading worldwide cause of cancer‑associated mortalities. Hepatocellular carcinoma, which accounts for the majority of liver tumors, ranks fifth among types of human cancer. Well‑established risk factors for liver cancer include the hepatitis B and C viruses, aflatoxins, alcohol consumption, and oral contraceptives. Tobacco smoking, androgenic steroids, and diabetes mellitus are suspected risk factors. Current knowledge regarding non‑infective occupational risk factors for liver cancer is inconclusive. The relevance of liver disorders to occupational medicine lies in the fact that the majority of chemicals are metabolized in the liver, and toxic metabolites generated via metabolism are the predominant cause of liver damage. However, their non‑specific clinical manifestations that are similar in a number of liver diseases make diagnosis difficult. Furthermore, concomitant conditions, such as viral hepatitis and alcohol or drug abuse, may mask liver disorders that result from occupational hepatotoxic agents and block the demonstration of an occupational cause. The identification of environmental agents that result in human cancer is a long and often difficult process. The purpose of the present review is to summarize current knowledge regarding the association of non‑infective occupational risk exposure and HCC, to encourage further research and draw attention to this global occupational public health problem.

Hepatocellular carcinoma (HCC) is the most common type of liver cancer. The main risk factors for HCC are alcoholism, hepatitis B virus, hepatitis C virus, nonalcoholic steatohepatitis, obesity, type 2 diabetes, cirrhosis, aflatoxin, hemochromatosis, Wilson's disease and hemophilia. Occupational exposure to chemicals is another risk factor for HCC. Often the relationship between occupational risk and HCC is unclear and the reports are fragmented and inconsistent. This review aims to summarize the current knowledge regarding the association of infective and non-infective occupational risk exposure and HCC in order to encourage further research and draw attention to this global occupational public health problem.