82(Suppl. 1).
doi:
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Objectives: In their 2022 classification of firefighting as carcinogenic, the International Agency for Research on Cancer deemed the evidence of the association with prostate cancer (PC) ‘limited’, citing an inability to rule out that a medical surveillance bias fully explained firefighters’ excess PC incidence compared to the general population. Our aim was to compare PC risk within a firefighter cohort, applying indicators of exposures.
Methods: We used employment duration and the indicators fire exposure score, inhalation score and diesel exhaust exposure score to examine PC risk among men in the Norwegian Fire Departments Cohort (n=4251). Incident PC cases, including clinical characteristics, were obtained from the Cancer Registry of Norway (1960–2021). Cox regression was used to estimate hazard ratios (HRs) by cumulative exposure in tertiles (reference: lowest) for all, aggressive, and indolent PCs, with adjustment for age and birth cohort. The cumulative incidence of PC across birth cohorts and diagnostic periods was examined.
Results: During 123,835 person-years of follow-up, there were 268 PC cases (61 aggressive, 69 indolent, 138 unclassifiable). No clear associations emerged for any of the exposure indicators, although elevated HRs were observed for aggressive PCs in the highest tertile of fire exposure score compared to the lowest (1.51, 95% CI 0.63–2.72), and for indolent PCs in the highest tertile of inhalation score compared to the lowest (1.31, 95% CI 0.60–2.89). Assessment of cumulative incidence by stage demonstrated a greater number of diagnoses of indolent and unclassifiable PC at younger ages from 1990.
Conclusions: We did not observe clear associations between our exposure indicators and PC risk. However, our study had few cases in analyses by clinical stage. Studies of PC risk among firefighters remain challenged by difficulties in exposure characterization and a limited understanding of PC etiology, as well as the unclear magnitude of a medical surveillance bias.
Funding: This work was funded by the Foundation Dam (grant no: 2019/FO247424), Cancer Society of Norway, Norwegian Firefighters Fight Cancer, Norwegian Union of Municipal and General Employees, Norwegian Union of Marine Engineers, and the Fire Union in Delta.
Acknowledgements: We wish to thank Jarle Jakobsen (Nordland Hospital, Bodø, Norway) for his work in the early stages of this study. We also wish to thank the fire departments that collected and shared their data that constitutes the Norwegian Fire Departments Cohort, as well as our project reference group (comprising representatives from firefighters’ unions, employers’ organisations, the volunteer organisation ‘Norwegian Firefighters Fighting Cancer’, the Norwegian Directorate for Civil Protection, the Norwegian Labour Inspection Authority, and the Norwegian Cancer Society) for their contributions to the project.
