The Health Watch Study

Project Team

• Professor Karen Walker-Bone
• Emeritus Professor Malcolm Sim AM
• Professor Deborah Glass
• Research Officer, Ms Elisa Wood
• Statistician, Mr Stephen Vander Hoorn

Contact

healthwatch@monash.edu

Funding

This project was funded from 1981 to 2023 by the Australian Institute of Petroleum.

Summary

Health Watch was an internationally heralded prospective cohort study of about 20,000 petroleum industry employees recruited since 1981, following them throughout their employment and beyond into retirement or other careers. It investigated the relationship between cancer incidence and causes of death in the industry.

Participation was voluntary; however, the employee participation rate was around 95% – clearly demonstrating the interest in and value of the Study to employees.

Cohort members were enrolled by completing a survey covering job details, lifestyle factors and health status, and remained enrolled for life. Cohort members were matched against data contained in the National Death Index and Australian Cancer Database to establish mortality and cancer incidence. This was then compared to expected sex- and age- matched rates from the general Australian population. Periodic reports were issued, and papers are published in peer-reviewed medical journals.

Health Watch had a long-standing history with MonCOEH, with the Centre administering the Study since 2005. The recent (16th) report was published in 2023.

Key findings

Overall, the Study clearly showed that petroleum industry employees were less likely to die from cancer and from heart, respiratory and digestive diseases than the general population.

Leukaemia has been a cancer of special concern in this industry because of its association with benzene exposure. Earlier Health Watch reports indicated a higher-than-expected number of leukaemia cases. However, more recent reports show that the risk of leukaemia is now lower than that of the general population.

One leukaemia type known to be associated with benzene exposure is Acute Myeloid Leukaemia (AML). There were 24 cases of this type of leukaemia in the Health Watch cohort, but this is lower than the 32 cases which would be expected, based on rates in the Australian population.

There have been 63 cases of mesothelioma diagnosed among Health Watch members. This cancer is strongly associated with asbestos exposure. According to Monash University, it is likely that several of these cancers are related to asbestos exposure in refineries in the 1950s and 1960s, although it is possible that some could be from asbestos exposure outside the petroleum industry. It can take 30–40 years between exposure to asbestos and mesothelioma diagnosis.

Melanomas are diagnosed in petroleum industry workers at a higher rate than the background population, but the death rate is consistent with the general Australian population. The rate does not increase with increasing duration of employment. Prostate cancer rates follow a similar pattern.

Impact

Careful, individualised exposure assessment for a nested case control study looking at lymphohematopoietic cancer in the Health Watch cohort identified that leukaemia was associated with lower benzene exposures than previously thought.

The work led to a pooled analysis with Canadian and UK data. The consequent 2012 myelodysplastic syndrome paper has been used as one of two epidemiological studies as the basis for the Dutch Occupational Exposure Limit for benzene (2013). It is also used in the World Health Organization’s International Agency for Research on Cancer (IARC) monograph 120 as a basis for the Group 1 carcinogenicity designation of benzene.

The work also resulted in the petroleum industry reporting a new occupationally related disease to the United States Environmental Protection Agency.

The benzene exposure metrics published in the Glass et al 2003 and 2005 papers were used by the German Government as thresholds of occupational exposure for the purposes of compensation¹. The European Union’s Registration, Evaluation, Authorisation and Restriction of Chemical Substances (REACH) Regulations 2007 require the development of Derived No-Effect Levels (DNELs). The Glass et al (2006) paper is used as the point of departure for the benzene DNEL².

Key outputs

REPORTS

• Health Watch Wrap Up Report (PDF)
• 16th Report and Final Analysis, 2023 Health Watch (PDF)
• 15th Report, 2018 Health Watch (PDF)
• 14th Report, 2013 Health Watch (PDF)
• 13th Report, 2007 Health Watch (PDF)
• Reports produced prior to 2007 are available here

PUBLICATIONS

Glass DC, Wood E, Del Monaco A, Sim MR (2016). Cohort Profile: Health Watch – a 30-year prospective cohort study of Australian petroleum industry workers. International Journal of Epidemiology, 45(3):700-6. doi: 10.1093/ije/dyv121.

Rushton L, Schnatter AR, Tang G, Glass DC (2014). Acute myeloid and chronic lymphoid leukaemias and exposure to low-level benzene among petroleum workers. British Journal of Cancer, 110(3), 783–787. doi: 10.1038/bjc.2013.780.

Glass DC, Schnatter AR, Tang G, Irons RD, Rushton L (2014). Risk of myeloproliferative disease and chronic myeloid leukaemia following exposure to low-level benzene in a nested case-control study of petroleum workers. Occupational and Environmental Medicine, 71(4), 266–274. doi: 10.1136/oemed-2013-101664.

Schnatter AR, Glass DC, Tang G, Irons RD, Rushton L (2012). Myelodysplastic syndrome and benzene exposure among petroleum workers: an international pooled analysis. Journal of the National Cancer Institute, 104(22), 1724–1737. doi: 10.1093/jnci/djs411.

Vlaanderen J, Portengen L, Rappaport SM, Glass DC, Kromhout H, Vermeulen R (2011). The impact of saturable metabolism on exposure-response relations in 2 studies of benzene-induced leukemia. American Journal of Epidemiology, 174(5), 621–629. doi: 10.1093/aje/kwr118.

Glass DC, Armstrong TW, Pearlman ED, Verma DK, Schnatter AR, Rushton L (2010). Ensuring comparability of benzene exposure estimates across three nested case-control studies in the petroleum industry in support of a pooled epidemiological analysis. Chemico-Biological Interactions, 184(1-2), 101–111. doi: 10.1016/j.cbi.2009.11.003.

Glass DC, Gray CN, Jolley DJ, Gibbons C, Sim MR (2006). The Health Watch Case-Control Study of Leukemia and Benzene: The Story So Far. Annals of the New York Academy of Sciences, 1076, 80–89. doi: 10.1196/annals.1371.024.

Glass DC, Gray CN, Jolley DJ, Gibbons C, Sim MR (2005). Health Watch exposure estimates: do they underestimate benzene exposure? Chemico-biological interactions, 153-154, 23–32. doi: 10.1016/j.cbi.2005.03.006.

Glass DC, Gray CN, Jolley DJ, Gibbons C, Sim MR, Fritschi L, Adams GG, Bisby JA, Manuell R (2003). Leukemia risk associated with low-level benzene exposure. Epidemiology (Cambridge, Mass.), 14(5), 569–577. doi: 10.1097/01.ede.0000082001.05563.e0.