Background: In 2012, the International Agency for Research on Cancer classified tetrachloroethylene, used in the production of chemicals and the primary solvent used in dry cleaning, as “probably carcinogenic to humans” based on limited evidence of an increased risk of bladder cancer in dry cleaners.
Objectives: We assessed the epidemiological evidence for the association between tetrachloroethylene exposure and bladder cancer from published studies estimating occupational exposure to tetrachloroethylene or in workers in the dry-cleaning industry.
Methods: Random-effects meta-analyses were carried out separately for occupational exposure to tetrachloroethylene and employment as a dry cleaner. We qualitatively summarized exposure–response data because of the limited number of studies available.
Results: The meta-relative risk (mRR) among tetrachloroethylene-exposed workers was 1.08 (95% CI: 0.82, 1.42; three studies; 463 exposed cases). For employment as a dry cleaner, the overall mRR was 1.47 (95% CI: 1.16, 1.85; seven studies; 139 exposed cases), and for smoking-adjusted studies, the mRR was 1.50 (95% CI: 0.80, 2.84; 4 case–control studies).
Conclusions: Our meta-analysis demonstrates an increased risk of bladder cancer in dry cleaners, reported in both cohort and case–control studies, and some evidence for an exposure–response relationship. Although dry cleaners incur mixed exposures, tetrachloroethylene could be responsible for the excess risk of bladder cancer because it is the primary solvent used and it is the only chemical commonly used by dry cleaners that is currently identified as a potential bladder carcinogen. Relatively crude approaches in exposure assessment in the studies of “tetrachloroethylene-exposed workers” may have attenuated the relative risks.
1Section of Environment and Radiation, and 2Section of IARC Monographs, International Agency for Research on Cancer, Lyon, France; 3National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, Ohio, USA; 4Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Maryland, USA; 5Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark; 6Department of Public Health, University of Copenhagen, Copenhagen, Denmark; 7Université de Lyon/Unité Mixte de Recherche Epidémiologique et de Surveillance Transport Travail Environnement (IFSTTAR/UCBL), Lyon, France; 8Finnish Institute of Occupational Health, Helsinki, Finland; 9Finnish Cancer Registry, Institute for Statistical and Epidemiological Cancer Research, Helsinki, Finland; 10School of Health Sciences, University of Tampere, Tampere, Finland; 11Cancer Registry of Norway, Oslo, Norway; 12Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden; 13Department of Community Medicine, Faculty of Health Sciences, University of Tromsø, The Arctic University of Norway, Tromsø, Norway; 14Folkhälsan Research Center, Samfundet Folkhälsan, Helsinki, Finland
Recommended Citation:
Jelle Vla,eren,1 Kurt Straif,et al. Tetrachloroethylene Exposure and Bladder Cancer Risk: A Meta-Analysis of Dry-Cleaning-Worker Studies[J]. Environmental Health Perspectives,2014-01-01,Volume 122(Issue 7):661