8285912 Exposure to dust and fibres and risk of lung cancer in 25,000 offshore oil industry workers

<h3>Objective</h3> In the offshore working environment, exposure to crystalline silica dust (CSD), asbestos and refractory ceramic fibres (RCF) may occur during offshore maintenance and drilling activities. Yet, no assessment of lung cancer risk according to job exposure matrices (JEMs) of these agents has been performed in offshore petroleum workers. Considering the ongoing debate about banning CSD-containing engineered stone products, we aimed to investigate the relationship between CSD and lung cancer risk using causal inference methodology. <h3>Material and Methods</h3> A case-cohort study was conducted on 475 lung cancer cases and 2015 randomly drawn non-cases in the Norwegian Offshore Petroleum Workers cohort followed up for cancer in the Cancer Registry of Norway 1999–2022. CSD, asbestos, and RCF exposure were assessed with expert-made JEMs. Cumulative incidence of lung cancer with 95% confidence intervals (CIs) was estimated, with death as a competing event, adjusted for age, first year of offshore employment, tobacco smoking, asbestos, and welding fumes using inverse probability of treatment weights. Additional analyses for histological subtypes were conducted. <h3>Results</h3> Among workers with the highest cumulative CSD exposure, an increased absolute risk of overall lung cancer was found after 5 years (0.8%, 95% CI: 0.4–2.1%) and 22 years of follow-up (4.2%, 95% CI: 2.6–6.7%). In workers unexposed to CSD, the corresponding estimates were 0.3% (95% CI: 0.2–0.4%) and 1.9% (95% CI: 1.6–2.4%). Similar results were found for squamous cell carcinoma (SCC) and small cell lung cancer (SCLC) after 5 years (SCC=0.2% (95% CI: 0.03–1.7%), SCLC=0.3% (95% CI: 0.09–1.2%)) and 22 years (SCC=1.1% (95% CI: 0.5–2.3%), SCLC=0.8% (95% CI: 0.3–1.8%)). No increased risk was found for asbestos or RCF. <h3>Conclusion</h3> High cumulative exposure to CSD may increase the absolute risk of lung cancer, overall and by histological subtypes, in offshore petroleum workers.