P049 Cancer incidence in western australian miners (1996–2013)

Objectives The mining industry is associated with exposures to a range of established and potential carcinogens (e.g. radiation and particulates from metals, crystalline silica, diesel exhaust, etc.). We aimed to assess the full spectrum of cancer incidence in miners relative to the general population and to identify specific subgroups at risk. Methods Cancer registry data identified cancer incidence in a cohort of 222,899 mine workers (87% male, mean age: 34 ± 11 years) in Western Australia during 1996–2013. Indirectly standardised incidence ratios (SIRs) were calculated and multivariable Poisson models were used to evaluate ever-underground work, employment commencement year and employment tenure as predictors of cancer incidence within miners after adjusting for age, sex, ever-smoker status and socioeconomic status. Results Among miners, 4,884 cancers over 1,826,498 person-years were identified. Both female (SIR: 0.81, 95% CI: 0.73–0.90) and male (SIR:0.89, 95% CI:0.87–0.92) miners had lower cancer incidence than the general population. Significantly greater risks were observed for cancers of the bones (SIR:2.10, 95% CI: 1.36–2.84), larynx (SIR: 1.42, 95% CI: 1.05–1.80) and melanoma (SIR: 1.16, 95% CI: 1.08–1.24) in males. Within miners, those commencing employment before 1996 had elevated risks for any cancer (Incidence Rate Ratio (IRR):1.11, 95% CI: 1.02–1.22) than their counterparts, in particular mesothelioma, brain, lung, liver and colorectal cancers. With the exception of testicular cancer (trend IRR: 1.27, 95% CI: 1.06–1.51), risks for mesothelioma and brain, bone, lung, pharyngeal, stomach, colorectal and any cancer (trend IRR: 0.92, 95% CI: 0.89–0.95) declined with increasing employment tenure. Ever working underground was positively associated with lung (IRR:1.60, 95% CI: 1.11–2.32) and renal (IRR: 1.79, 95% CI: 1.03–3.12) cancer. Conclusion The healthy worker effect possibly explains miners’ lower incidence of most cancers compared with the general population. Short-tenured and underground miners were at risk of certain cancers, not limited to the lung. Forthcoming studies will need to evaluate the role of mining exposures in these cancers in the occupational sub-groups.