The Health Watch Study

Chief Investigators

Health Watch logoProject staff

Funding

Australian Institute of Petroleum

Estimated completion date

This is an ongoing project, it has been funded since 1981, and is currently funded through until 2022.

Summary

This is 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 is investigating the relationship between cancer incidence and causes of death in the industry.

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

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

The Health Watch project has a long-standing history with MonCOEH, with the Centre administering the project since 2005.The latest report (15th) was published in 2018, and the Health Watch team have been funded to conduct another data linkage round in 2022.

Impact

Careful, individualised exposure assessment for 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 lead 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 findings

Overall, the Study clearly shows that petroleum industry employees are 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 no greater than that of the general population.

One leukaemia type known to be associated with benzene exposure is Acute Myeloid Leukaemia (AML). There are 18 cases of this type of leukaemia in the Health Watch cohort, but this is lower than the 25 cases which would be expected, based on rates in the Australian population.

There have been 49 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.

Key outputs

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

Contact

healthwatch@monash.edu

References

  1. German Government ordinance on Occupational diseases, OD No. 1303 "diseases of the blood, the hematopoietic and lymphatic system caused by benzene". Beelte S, Haas R, Germing U, Jansing PJ. Med Klin (Munich). 2009 Mar 15;104(3):197-203. doi: 10.1007/s00063-009-1032-8. [Paradigm change in the assessment of myeloid and lymphoid neoplasms associated with occupational benzene exposure]. Article in German.
  2. Degen G (2012) Presentation: Exposure-risk relationship for benzene. Position paper of the German AGS. Brasilian Benzene Seminar 6th December 2012. https://de.slideshare.net/radarrt/07-gisela-degen