Coexposure to asbestos, mineral wool, crystalline silica and refractory ceramic fibres and risk of lung cancer and mesothelioma.

BACKGROUND

Asbestos, mineral wool (MW), refractory ceramic fibres (RCF) and silica are among the most common exposures to mineral particles in the workplace.

OBJECTIVE

To study the effect of coexposure to asbestos and MW, crystalline silica or RCFs and the risk of lung cancer and mesothelioma.

METHODS

The Asbestos-Related Diseases Cohort is a surveillance programme in retired workers exposed to asbestos during their working life. Complete job histories were collected and occupational exposure to asbestos was assessed by an expert, while occupational exposure to MW, RCFs and silica was assessed using French job-exposure matrices. Cox proportional hazards models were used to estimate HR and 95% CI for lung cancer mortality and lung cancer incidence and for mesothelioma mortality or mesothelioma incidence.

RESULTS

In this population of workers exposed to asbestos, in the mortality study, exposures to MW, crystalline silica and RCFs were not found to be associated with lung cancer after adjustment for smoking and asbestos, nor with mesothelioma after adjustment for asbestos. In the incidence study, there was an association between exposure to crystalline silica (ever exposed) and mesothelioma (HRa=1.75, 95% CI 1.17 to 2.62).

CONCLUSION

Crystalline silica is not known to induce mesothelioma but coexposure to asbestos could increase the effect of asbestos on the mesothelial cells.