Risk of testicular cancer and exposure to welding fumes

The incidence of germ-cell testicular cancer (TC) has increased in recent decades. Current evidence does not indicate a unanimous association between occupational exposure to welding fumes and TC risk. However, most publications do not provide information on exposure levels to welding fumes. We investigated the association between occupational exposure to welding fumes and the risk of TC in a German case-control study (268 cases and 797 control subjects). A measurement-based welding-exposure matrix was used to estimate year-specific exposure values which were linked to job-task descriptions. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated via logistic regression, conditional on study area and 5-year age groups. ORs were adjusted for a history of cryptorchidism, a family history of TC, and ever exposure to metal-working fluids (MWF). Regular welding was associated with an elevated TC risk (OR: 2.26, CI: 0.92-5.53) compared to occasional welding (OR: 1.14, CI: 0.78-1.69). For non-seminoma, there was an indication of a strong association among regular welders (OR: 3.71, CI: 1.08-12.80) and for non-welders using MWFs (OR: 3.39, CI: 1.21-9.53). However, these estimates were based on few exposed cases. We did not observe dose-effect relationships with increasing lifetime exposure to welding fumes, duration, or average intensity. We found an association between regular welding and TC risk based on standardized job-task descriptions, but not when using the year-specific exposure values.