Work-related lung cancer concentrate among lower status workers: a quantification approach

Abstract

Background/Aim: Although the concentration of carcinogenic exposures within specific socio-occupational groups is widely acknowledged, most burden of disease (BOD) approaches focus on the general population, missing the dimension of occupational health inequities. This raises social justice issues as those quantification tools are increasingly used for discussing cancer prevention priorities and occupational disease compensation rules. Our general aim was to explore ways by which population health metrics could integrate occupational inequities, and to identify eventual data gaps. Our specific aim was to compare the burden of work-related lung cancer between different socio-economic groups taking into account three known occupational carcinogens (asbestos, silica and DME) and smoking. Methods: We conducted a secondary analysis of the population-based case-control study ICARE (Investigation sur les Cancers Respiratoires et l’Environnement). The study included 2926 lung cancer cases and 3555 frequency-matched controls covering 13% of the French population. Lifelong occupational exposures were assessed by job-exposure matrices and self-report. We compared sources of variation in the attributable fractions (AF) estimates, including interaction with socio-economic position (SEP) and SEP indicator (education or occupation-based), using STATA. Results: The analysis was based on men-only due to the limited number of exposures among women. The AF for the combined indicator of asbestos, silica and DME exposures was 29.4% (95%CI [23.9-34.4]) overall, while the AF for exposed blue-collar workers compared to non-exposed groups regardless of SEP was 26.9% (95%CI [21.9- 31.7]). AFs were slightly higher when capturing SEP through education. Our results provide quantified evidence that the burden of work-related lung cancer attributable to these 3 known carcinogens concentrates massively (over 90%) among manual workers. Conclusion: They exemplify the need for integrating indicators of occupation and industry sector into BOD estimates to inform decision-making in cancer prevention and compensation. More broadly, they plead for information systems linking SEP, environmental and occupational health.