Vinyl chloride

From

Summary

TBD.

Studies and Reports

• Sahmel J et al., The use of multizone models to estimate an airborne chemical contaminant generation and decay profile: occupational exposures of hairdressers to vinyl chloride in hairspray during the 1960s and 1970s, Risk Anal. 29(12):1699-725, December 2009.
  • Abstract. "Vinyl chloride (VC) was used as a propellant in a limited percentage of aerosol hairspray products in the United States from approximately 1967 to 1973. The question has arisen whether occupational exposures of hairdressers to VC-containing hairsprays in hair salons were sufficient to increase the risk for developing hepatic angiosarcoma (HAS). Transient two-zone and steady-state three-zone models were used to estimate the historical airborne concentration of VC for individual hairdressers using hairspray as well as estimated contributions from other hairdressers in the same salon. Concentrations of VC were modeled for small, medium, and large salons, as well as a representative home salon. Model inputs were determined using published literature, and variability in these inputs was also considered using Monte Carlo techniques. The 95th percentile for the daily time-weighted average exposure for small, medium, and large salons, assuming a market-share fraction of VC-containing hairspray use from the Monte Carlo analysis, was about 0.3 ppm, and for the home salon scenario was 0.1 ppm. The 95th percentile value for the cumulative lifetime exposure of the hairdressers was 2.8 ppm-years for the home salon scenario and 2.0 ppm-years for the small, medium, and large salon scenarios. If using the assumption that all hairsprays used in a salon contained VC, the 95th percentile of the theoretical lifetime cumulative dose was estimated to be 52-79 ppm-years. Estimated lifetime doses were all below the threshold dose for HAS of about 300 to 500 ppm-years reported in the published epidemiology literature."
• Sherman M, Vinyl chloride and the liver, J Hepatol. 2009 Dec;51(6):1074-81. Epub 2009 Oct 1.
  • Abstract. "Vinyl chloride monomer is a known cause of angiosarcoma of the liver. It also has other toxic effects on the liver, and it has recently been suggested that exposure to vinyl chloride also causes hepatocellular carcinoma. However, the data on which this conclusion is based is incomplete. There is inadequate ascertainment of unequivocal diagnoses. In the largest studies lack of data meant that confounding diseases such as viral hepatitis or alcoholic liver disease could not be assessed. At best, the increase in risk is minimal, based on more than 22,000 exposed workers and more than 640,000 person years of observation. However, based on the available data the hypothesis that vinyl chloride causes or contributes to the development of hepatocellular carcinoma remains unproven."
• Dragani T and Zocchetti C, Occupational exposure to vinyl chloride and risk of hepatocellular carcinoma, Cancer Causes Control. 2008 Dec;19(10):1193-200. Epub 2008 Jun 17.
  • Abstract. "Hepatocellular carcinoma (HCC) is a common form of cancer that arises from hepatocytes and whose risk may be affected by several known factors, including viruses, alcohol, cigarette smoking, and several genetic conditions. Liver angiosarcoma is a rare cancer that develops from endothelial cells and whose most relevant known risk factor is occupational exposure to vinyl chloride (VC). Since occupational exposure to high levels of VC may still occur, we reviewed the epidemiological and experimental evidence supporting the notion that inhalation exposure to VC is a risk factor for HCC. We find that available epidemiological evidence is based on a dose-risk study with 10 HCC cases and on a partially overlapping study reporting similar results: neither study provided controls for known non-occupational confounders for HCC. Carcinogenesis bioassays of VC inhalation in rodents indicate that angiosarcomas account for nearly all liver tumors induced. Thus, the role of inhalation exposure to VC in HCC risk remains unclear, awaiting further studies and the integration of results from epidemiological studies and animal models."
• Scelo G et al., Occupational exposure to vinyl chloride, acrylonitrile and styrene and lung cancer risk (Europe), Cancer Causes Control. 2004 Jun;15(5):445-52.
  • Abstract. "Several industry-based cohort studies have addressed the risk of lung cancer following exposure to vinyl chloride, acrylonitrile and styrene, with inconsistent results and usually without smoking adjustment. These exposures are addressed here in a large case-control study with full adjustment for smoking. Almost 6000 subjects were included in a case-control study conducted in seven European countries. For each job they held, local experts assessed the exposure to a number of occupational agents, including vinyl chloride, acrylonitrile and styrene, on the basis of detailed occupational questionnaires. Information on tobacco consumption and other risk factors was also collected. The odds ratio (OR) for ever exposure to vinyl chloride was 1.05 (95% confidence interval, CI: 0.68-1.62) and a modest, non-significant increase in the risk of lung cancer was found in the highest exposed subgroup. The OR for ever exposure to acrylonitrile was 2.20 (95% CI: 1.11-4.36) with a positive dose-response relationship between estimated cumulative exposure and lung cancer risk. No association between exposure to styrene and lung cancer risk was found. In conclusion, we cannot exclude a weak association between occupational exposure to vinyl chloride and lung cancer risk. Exposure to acrylonitrile was associated in our study with risk of lung cancer. Exposure to styrene does not seem to increase lung cancer risk."
• Bocetti C et al., Occupational exposure to vinyl chloride and cancer risk: a review of the epidemiologic literature, Eur J Cancer Prev. 2003 Oct;12(5):427-30.
  • Abstract. "Occupational exposure to vinyl chloride (VC) is causally related to liver angiosarcoma, whereas there is inconsistent epidemiologic evidence for other neoplasms. Two pooled analyses of worker cohorts from 56 plants in North America and Europe provide the most comprehensive and updated data on cancer risk among workers exposed to VC. These included over 22,000 workers, with a total of 640,000 person-years of observation, followed-up for up to 50 years. Overall, a total of 1,778 cancer deaths were observed versus 1,829.46 expected, corresponding to a standardized mortality ratio (SMR) of 0.97 (95% confidence interval (CI)=0.93-1.02). Excluding 71 confirmed angiosarcomas, there were 60 deaths from liver cancers versus 44.35 expected (SMR=1.35, 95% CI=1.03-1.74). Lung and laryngeal cancer mortality were significantly lower than expected (SMR=0.88 and 0.59, respectively). The SMRs for soft tissue sarcoma, brain, lymphoid and haematopoietic system cancers were not materially different from unity. Thus, the aggregate data from over 20,000 VC workers in North America and Europe exclude any excess mortality from lung, laryngeal, soft tissue sarcoma, brain, lymphoid and haematopoietic neoplasms. There appears to be a slight excess of liver cancer other than angiosarcoma, which is difficult to interpret and is likely due to residual misclassification of angiosarcomas."
• Boffetta P et al., Meta-analysis of studies of occupational exposure to vinyl chloride in relation to cancer mortality, Scand J Work Environ Health. 2003 Jun;29(3):220-9.
  • Abstract. "Apart from the known risk of ASL, workers exposed to vinyl chloride may experience an increased risk of hepatocellular carcinoma and soft-tissue sarcoma; however, these results may have been influenced by the underdiagnosis of true ASL. Increased mortality from lung and brain cancers and from lymphatic and hematopoietic neoplasms cannot be excluded; mortality from other neoplasms does not appear to be increased."
• Lewis R et al., Vinyl chloride and liver and brain cancer at a polymer production plant in Louisville, Kentucky, J Occup Environ Med. 2003 May;45(5):533-7.
  • Abstract. "Studies of overlapping cohorts in the United States have shown an excess mortality from brain cancer in vinyl chloride (VC)-exposed workers. One plant located in Louisville, Kentucky, is included in many of these studies. We separated this plant from the large US cohort and re-analyzed the mortality experience. Louisville experienced significantly elevated liver (standardized mortality analyses [SMR] = 400) and brain cancer (SMR = 229) mortality. Liver cancer mortality remained significantly elevated (SMR = 344) in the remaining cohort; however, brain cancer mortality was markedly reduced (SMR = 112) when Louisville was removed. In contrast with liver cancer, a preliminary review of work assignments did not suggest that the brain cancer excess was related to VC exposure. The Louisville brain cancer cluster has had a significant impact on the reported literature. Although unrelated to VC, the cause of this cluster remains uncertain."
• McLaughlin J and Lipworth L, A critical review of the epidemiologic literature on health effects of occupational exposure to vinyl chloride, J Epidemiol Biostat. 1999;4(4):253-75.
  • Abstract. "We have attempted to critically review and summarise the collective epidemiologic evidence concerning the association of occupational vinyl-chloride exposure with human health outcomes, including cancer, liver cirrhosis, cardiovascular disease, nonmalignant respiratory disease and acroosteolysis. Based on data from individual reports, qualitative and, where possible, quantitative summaries are presented. With respect to cancer, which has been extensively studied, angiosarcoma of the liver is the only malignancy causally related to vinyl-chloride exposure. Hypothesised associations between vinyl chloride and cancers of other sites, namely lung, brain and lymphohaematopoietic system, are not consistently supported by the available data. Similarly, the epidemiologic data relating vinyl chloride to nonmalignant disease, while quantitatively limited and qualitatively suboptimal, do not support a causal association for any of the studied disorders. In summary, a comprehensive review of the relevant epidemiologic literature revealed that occupational vinyl-chloride exposure has not been conclusively or causally linked to any adverse health outcome, with the exception of angiosarcoma of the liver."
• Simonato L et al., A collaborative study of cancer incidence and mortality among vinyl chloride workers, Scand J Work Environ Health. 1991 Jun;17(3):159-69.
  • Abstract. "A large European multicentric cohort study has been coordinated by the International Agency for Research on Cancer with the objectives of investigating the dose-response relationship between liver cancer and exposure to vinyl chloride and assessing cancer risk for sites other than the liver. A nearly threefold increase in liver cancer was detected on the basis of 24 observed deaths and 8.4 expected (standardized mortality ratio 286, 95% confidence interval 186-425). The excess from liver cancer was clearly related to time since first exposure, duration of employment, and estimated ranked and quantitative exposures. Other cancer sites investigated on the basis of a priori hypotheses were either not in excess (lung) or apparently unrelated to the exposure variables (brain and lymphoma)."
• Wong O et al., An industry-wide epidemiologic study of vinyl chloride workers, 1942-1982, Am J Ind Med. 1991;20(3):317-34.
  • Abstract. "The cohort consisted of 10,173 men who had worked for at least one year in jobs involving exposure to vinyl chloride prior to 1 January 1973. These men were employed at 37 plants in the U.S., belonging to 17 companies. Observation of the mortality experience of the cohort was updated from 31 December 1972 to 31 December 1982 (the study now covering 1942-1982). A total of 1,536 cohort members were identified as having died. The observed mortality, by cause, was compared with the expected based on U.S. mortality rates, standardized for age, race, and calendar time. Analyses by length of exposure, latency, age at first exposure, calendar year of first exposure, and type of products were performed. The study confirmed that the vinyl chloride workers experience a significant mortality excesses in angiosarcoma (15 deaths), cancer of the liver and biliary tract (SMR = 641), and cancer of the brain and other central nervous system (SMR = 180). In addition, the study also found a significant mortality excess in emphysema/chronic obstructive pulmonary disease (COPD) (SMR = 179). On the other hand, the study did not find any excess in either respiratory cancer or lymphatic and hematopoietic cancer. This study also found an increase in biliary tract cancers, independent from liver cancer."
• Wu W et al., Cohort and case-control analyses of workers exposed to vinyl chloride: an update, J Occup Med. 1989 Jun;31(6):518-23.
  • Abstract. "The mortality in a cohort of workers at a vinyl chloride polymerization plant has been updated, extending the period of observation in the original study from 1974 to 1986. Workers at this plant may have been exposed to vinyl chloride monomer and/or polyvinyl chloride dust, or may have had no exposure to either substance. Seventy-six percent of the work force worked in jobs with potential exposure to vinyl chloride monomer. Among the total cohort, statistically significant excess risks were observed for liver, lung, and brain cancer. For the subcohort of workers exposed to vinyl chloride monomer, the standardized mortality ratio (SMR) for liver cancer was 333 (90% confidence interval (CI) 202 to 521). However, there were no significant excesses of either brain (SMR = 145, 90% CI 78 to 249) or lung cancer (SMR = 115, 90% CI 96 to 141). To investigate dose response, nested case-control studies for liver, brain, and lung cancer were conducted among the total cohort (including the nonexposed). For these studies there were two exposure variables, cumulative dose of vinyl chloride monomer and cumulative dose of polyvinyl chloride dust. Cumulative dose was defined as the product of level and duration of exposure. The only significant association between disease risk and cumulative dose was for liver cancer and cumulative dose of vinyl chloride monomer. Further division of the liver cancers into angiosarcoma (n = 12) and other liver cancers (n = 7), based on review of death certificates and medical records, showed that the dose response existed only for angiosarcomas."
• Jone R et al., A mortality study of vinyl chloride monomer workers employed in the United Kingdom in 1940-1974, Scand J Work Environ Health. 1988 Jun;14(3):153-60.
  • Abstract. "The mortality experience of 5,498 male workers employed for at least one year during 1940-1974 in the vinyl chloride industry of the United Kingdom was followed through to 31 December 1984. There was a significant excess of nonsecondary liver tumors with 11 deaths, of which seven were angiosarcomas. All the angiosarcoma deaths occurred in autoclave workers with a median latency of 25 years from date of first exposure. A strong healthy worker effect was seen. Other than that for liver cancer, no increased incidence of cancer deaths attributable to vinyl chloride monomer exposure was found. There was no evidence of increased mortality from chronic liver disease. The incidence of death from respiratory disease was low and was not affected by polyvinyl chloride dust exposure."
• Doll R, Effects of exposure to vinyl chloride. An assessment of the evidence, Scand J Work Environ Health. 14(2):61-78, April 1988.
  • Abstract. "This paper reviews the possible effects of vinyl chloride on the mortality of occupationally exposed men and the carcinogenic effects that might be observed in the general population as a result of environmental pollution with vinyl chloride. The results of four studies fulfilling the criteria of providing substantial numbers of observations more than 25 years after first exposure and covering a period long enough for more than 10% of the workers to have been expected to die constitute the basis for the assessment of the occupational hazards. Other studies provide only supplementary information. The data permit two conclusions. First, men occupationally exposed to vinyl chloride have experienced a specific hazard of angiosarcoma of the liver. Second, any other occupational hazards that may have existed have been small. No positive evidence of a hazard of any nonmalignant disease or any type of cancer other than angiosarcoma of the liver has been found except possibly for a small hazard of lung cancer when exposure was heavy. More definite conclusions might be reached if those who have studied exposed employees could present their results in appropriate and comparable ways. A very small risk of angiosarcoma may have occurred as a result of vinyl chloride escaping into the environment around plants handling vinyl chloride in the past, but the evidence indicates that the current risk to the general public (if any) must be negligible."
• Forman D et al., Exposure to vinyl chloride and angiosarcoma of the liver: a report of the register of cases, Br J Ind Med. 42(11):750-3, November 1985.
  • Abstract. "The Association of Plastic Manufacturers in Europe maintains a register of all cases of angiosarcoma of the liver (ASL) resulting from exposure to vinyl chloride monomer (VCM). This register has recorded all known VCM related cases of the disease worldwide that have been histologically confirmed. Although likely to be incomplete, it is the most comprehensive tabulation of such cases available and, by the end of 1984, 118 men had been registered. The information from analysis of the cases currently on the register is used to make an approximate projection of the number of cases to be expected in the future. The conclusion from this projection is that the industry is reaching the halfway stage in the appearance of VCM related ASL."