title: Risk of cancer among workers exposed to trichloroethylene: analysis of three Nordic cohort studies.
abstract: BACKGROUND
  Trichloroethylene (TCE) is a widely used chlorinated solvent with demonstrated carcinogenicity in animal assays. Some epidemiologic studies have reported increased risk of cancer of the kidney, cervix, liver and biliary passages, non-Hodgkin lymphoma, and esophageal adenocarcinoma.
  
  
  METHODS
  We established a pooled cohort, including 5553 workers with individual documented exposure to TCE in Finland, Sweden, and Denmark. Study participants were monitored for the urinary TCE metabolite trichloroacetic acid from 1947 to 1989 and followed for cancer. Standardized incidence ratios (SIRs) were calculated based on cancer incidence rates in the three national populations. Cox proportionate hazard analyses were used for internal comparisons. Tests of statistical significance are two-sided.
  
  
  RESULTS
  Overall, 997 cases of cancer (n = 683 in men; n = 314 in women) were identified during 154 778 person-years of follow-up. We observed statistically significant elevated standardized incidence ratios for primary liver cancer (1.93; 95% confidence interval [CI] = 1.19 to 2.95) and cervical cancer (2.31; 95% CI = 1.32 to 3.75). The standardized incidence ratio for kidney cancer was 1.01 (95% CI = 0.70 to 1.42) based on 32 cases; we did not observe a statistically significant increased risk of non-Hodgkin's lymphoma (SIR = 1.26; 95% CI = 0.89 to 1.73) or esophageal adenocarcinoma (SIR = 1.84; 95% CI = 0.65 to 4.65). Tobacco- and alcohol-associated cancers were not statistically significantly increased.
  
  
  CONCLUSIONS
  Our results suggest TCE exposure is possibly associated with an increased risk for liver cancer. The relationship between TCE exposure and risks of cancers of low incidence and those with confounding by lifestyle and other factors not known in our cohort require further study.
authors.affiliation: Danish Cancer Society Research Center, Copenhagen, Denmark. johnni@cancer.dk
authors.forename: Johnni
authors.initials: J
authors.lastname: Hansen
authors.forename: Markku
authors.initials: M
authors.lastname: Sallmén
authors.forename: Anders I
authors.initials: AI
authors.lastname: Seldén
authors.forename: Ahti
authors.initials: A
authors.lastname: Anttila
authors.forename: Eero
authors.initials: E
authors.lastname: Pukkala
authors.forename: Kjell
authors.initials: K
authors.lastname: Andersson
authors.forename: Ing-Liss
authors.initials: IL
authors.lastname: Bryngelsson
authors.forename: Ole
authors.initials: O
authors.lastname: Raaschou-Nielsen
authors.forename: Jørgen H
authors.initials: JH
authors.lastname: Olsen
authors.forename: Joseph K
authors.initials: JK
authors.lastname: McLaughlin
mesh_terms: D000230:Adenocarcinoma / Q000139:chemically induced / Q000453:epidemiology; D000328:Adult; D000368:Aged; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D004938:Esophageal Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007680:Kidney Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D008113:Liver Neoplasms / Q000139:chemically induced / Q000453:epidemiology; D008228:Lymphoma, Non-Hodgkin; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000139:chemically induced* / Q000453:epidemiology*; D009784:Occupational Diseases / Q000139:chemically induced* / Q000453:epidemiology*; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012997:Solvents / Q000506:poisoning*; D013548:Sweden / Q000453:epidemiology; D014238:Trichloroacetic Acid / Q000652:urine; D014241:Trichloroethylene / Q000378:metabolism / Q000506:poisoning*; D002583:Uterine Cervical Neoplasms / Q000139:chemically induced / Q000453:epidemiology
chemical_list: D012997:Solvents; D014241:Trichloroethylene; D014238:Trichloroacetic Acid