Milestone as 40 year worker cancer and mortality project wraps up

The landmark Australian study on workplace health, Health Watch, has concluded after more than 40 years monitoring the health of around 20,000 petroleum industry workers recruited since 1981.

With the release of the study’s 16th and final report this week, the study – funded by the Australian Institute of Petroleum – has ultimately provided independent reassurance around occupational cancer and mortality among petroleum workers, in particular leukaemia and mesothelioma. It’s also clearly shown that petroleum industry employees were less likely to die from cancer and from heart, respiratory and digestive diseases than the general population.

The study followed the health of those who enrolled, throughout their employment and beyond into retirement or other career fields. The researchers investigated the relationship between cancer incidence, and causes of death across the industry. Since 2005 the study has been administered by the Monash Centre for Occupational and Environmental Health (MonCOEH), housed within the University’s School of Public Health and Preventive Medicine.

Participation was voluntary, however the 95 per cent enrolment rate by workers underscored the incredible engagement and interest among those working in the sector.

Study spokesperson Professor Deborah Glass says, “Leukaemia – and in particular Acute Myeloid Leukaemia (AML) – has previously been shown to be associated with exposure to benzene, a by-product of petroleum processing, so there were understandably concerns among petroleum workers that they might be at higher risk of these cancers. I’m sure that probably drove great interest in the study in its earlier days.”

Since the start of Health Watch, there have been 24 diagnoses of AML. This is lower than the 32 instances that would be expected, based on rates among the general Australian population.

Sixty-three cases of mesothelioma were found among study participants. This cancer is strongly associated with asbestos exposure, and it is likely these developed among refinery workers exposed in the 1950s and 1960s.

Melanomas were diagnosed in male petroleum industry workers at a higher rate than seen in the background population, but the melanoma death rate was consistent with the general Australian population. The melanoma incidence rate does not increase with increasing duration of employment. This may suggest that cohort members are screened more often than the general population and so their melanomas are more likely to be treated successfully.

Study participants undertook an extensive survey upon enrolment, gathering information about their job details and lifestyle factors. Over time they were periodically matched against data drawn from Australia’s National Death Index and the Australian Cancer Database, to establish incidence of death and cancer diagnosis. This was then compared to expected sex- and age-matched rates from the general Australian population, with findings published in peer-reviewed medical journals.

Prof Glass says, “It’s a proud moment to close the book on such a long-lasting study. There’s been some very complex analysis over the years, which has contributed to important new understandings around the health risks of working in the field, and how to better protect petroleum industry workers from occupational diseases.

“The study has shown that leukaemia is actually associated with lower exposure to benzene than previously thought, which has changed practice for the better. We’ve collaborated with colleagues in Canada and the UK to produce a large data pool, the analysis of which underpinned updated safety standards in European countries, and in the World Health Organization’s decision to list benzene as a Group 1 carcinogen.

“Findings have driven the USA to add new occupational-related diseases to their reporting procedures, and have supported Germany’s decision to update thresholds of occupational exposure for worker’s compensation purposes in the industry.

“It’s been very rewarding to conduct this work over the years, and to see it drive changes to global practice and policy that have in turn driven better health outcomes for these workers.”

See more of MonCOEH’s research into at-risk worker health here.

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