Objectives Trichloroethylene, a chlorinated solvent widely used for metal degreasing, is classified by the International Agency for Research on Cancer as a kidney carcinogen. Other chlorinated solvents are suspected carcinogens, most notably the cleaning solvent perchloroethylene, although it is unclear whether they are associated with kidney cancer. We investigated kidney cancer associations with occupational exposure to 6 chlorinated solvents (trichloroethylene, perchloroethylene, 1,1,1-trichloroethane, carbon tetrachloride, chloroform, and methylene chloride) within a case–control study using detailed exposure assessment methods.
Methods Cases (n=1217) and controls (n=1235) provided information on their occupational histories and, for selected occupations, on tasks involving potential exposure to chlorinated solvents through job-specific interview modules. Using this information, an industrial hygienist assessed potential exposure to each solvent. We computed ORs and 95% CIs for different exposure metrics, with unexposed participants as the referent group.
Results 1,1,1-trichloroethane, carbon tetrachloride, chloroform, and methylene chloride were not associated with kidney cancer. Among jobs with high exposure intensity, high cumulative hours exposed to perchloroethylene was associated with increased risk, both overall (third tertile vs unexposed: OR 3.1, 95% CI 1.3 to 7.4) and after excluding participants with ≥50% exposure probability for trichloroethylene (OR 3.0, 95% CI 0.99 to 9.0). A non-significant association with high cumulative hours exposed to trichloroethylene was observed (OR 1.7, 95% CI 0.8 to 3.8).
Conclusions In this study, high exposure to perchloroethylene was associated with kidney cancer, independent of trichloroethylene. Additional studies are needed to further investigate this finding.
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Contributors JSC, FD, JR, KS, BIG, NR and W-HC contributed to the design, enrollment and/or data collection of the case-control study. PAS, MPP, MCF, SJL, MJH and MAW contributed to the exposure assessment. MPP, BIG, and JNH conducted or advised on the creation of study complex sampling weights and/or statistical analysis for this project. MPP drafted the manuscript. All authors contributed to the writing of the manuscript.
Funding This research was supported by the Intramural Research Program of the NIH and the National Cancer Institute.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Intramural Research Boards at the National Cancer Institute Wayne State University and University of Illinois-Chicago.
Provenance and peer review Not commissioned; externally peer reviewed.
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