Introduction In a previous analysis of a case–control study of testicular cancer nested in a cohort of automobile workers, we observed an increased risk for testicular cancer among workers who had ever been involved in occupational metal-cutting tasks. We investigated whether this risk increase was due to exposure to metal-working fluids (MWF).
Methods Occupational exposure to MWF was assessed in detail using a job-specific questionnaire for metal-cutting work. We calculated ORs and associated 95% CIs individually matched for age (±2 years) and adjusted for a history of cryptorchidism by conditional logistic regression.
Results The prevalence of exposure to MWF was 39.8% among cases and 40.1% among controls. For total germ cell tumours and seminomas we did not observe risk increases for metal-cutting tasks or occupational exposure to MWF (OR 0.95; 95% CI 0.69 to 1.32 and OR 0.88; 95% CI 0.58 to 1.35, respectively). However, dermal exposure to oil-based MWF was associated with an increased risk for non-seminomatous testicular cancer. Dermal exposure to oil-based MWF for more than 5000 h showed particularly high risk estimates (OR 4.72; 95% CI 1.48 to 15.09).
Discussion Long-term dermal exposure to oil-based MWF was a risk factor for the development of non-seminomatous testicular germ cell cancer. Possible measures to reduce exposure include the introduction of engineering control measures such as venting or enclosing of machines, and enforcing the use of personal protective equipment during metal cutting.
- metal industry
- metal-cutting fluids
- testicular cancer
- hygiene/occupational hygiene
- exposure assessment
- mortality studies
- biological monitoring
- public health
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Funding This work was funded by the ‘Vereinigung der Metall-Berufsgenossenschaften’ and the German Social Accident Insurance association (DGUV). We received supplementary funding from the company where the study was performed.
Competing interests We received supplementary funding from the company where the study was performed. We are independent of the company regarding study design, access to the collected data, responsibility for data analysis and interpretation, and the right to publish. The views expressed in this paper are those of the authors and not necessarily those of the sponsors.
Ethics approval Ethics approval was provided by the University of Bremen Ethics Committee.
Provenance and peer review Not commissioned; externally peer reviewed.