P-324 Benzene exposure and risk of lung cancer in the Norwegian offshore petroleum workers cohort

Background

The International Agency for Research on Cancer has classified benzene as carcinogenic to humans. However, the evidence for an association between benzene exposure and lung cancer risk is unclear. The Norwegian Offshore Petroleum Workers (NOPW) cohort contains individual data on smoking history, benzene and other occupational exposures, which may elucidate this relationship.

Methods

Among the 25 347 male offshore workers in the NOPW cohort employed during 1965–1998, we conducted a prospective case-cohort study with 399 lung cancer cases diagnosed in 1999–2021 and 2035 randomly drawn non-cases. Personal work histories were linked to job-exposure matrices for benzene and other occupational exposures. Weighted Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for overall lung cancer and histological subtypes, adjusted for age, smoking, welding fumes, asbestos, and crystalline silica.

Results

Compared to unexposed workers, no statistically significant increased risk of lung cancer overall was found in the highest quartile of cumulative benzene exposure (HR=1.05, 95% CI 0.57–1.94), exposure duration (HR=1.42, 95% CI 0.79–2.57), and average intensity (cumulative divided by duration) (HR=1.18, 95% CI 0.69–2.02). Moreover, no significant associations were found for the histological subtypes. A positive dose–response relationship was found between cumulative smoking exposure and risk of overall lung cancer: HR=4.09, 95% CI 2.79–5.98 for tertile 2, and HR=11, 95% CI 7.33–15 for tertile 3, compared to tertile 1.

Conclusion

We did not find evidence of an association between benzene exposure and lung cancer risk overall, nor for any major histological subtypes.