While this case-control study includes the Arnsberg area, several other regions are included as well, where the source of the trichloroethylene and chlorinated solvent exposures are much less well defined. As a result, most subjects identified as exposed to trichloroethylene probably had minimal contact, averaging concentrations of about 10 ppm or less.
This pair of studies evaluated mutations in the von Hippel-Lindau gene in subjects drawn from the Vamvakas et al. (1998) cohort. The findings were analyzed with the combination-exposure index that uses both exposure duration and severity of neurological symptoms.
This is an appropriate use of the Vamvakas et al. (1998) exposure assignments for the individual cases evaluated. These workers had substantial, sustained high exposures to trichloroethylene at concentrations of 400-600 ppm during hot dip cleaning and greater than100 ppm overall.