Case-control study on renal cell cancer and occupational exposure to trichloroethylene. Part I: Exposure assessment

Our plain-English summary of Case-control study on renal cell cancer and occupational exposure to trichloroethylene. Part I: Exposure assessment, by J. Fevotte, B. Charbotel, P. Muller-Beauté, et al (The Annals of Occupational Hygiene, 2006).

The study

• Authors: J. Fevotte, B. Charbotel, P. Muller-Beauté, J.L. Martin, M. Hours, A. Bergeret
• Journal: The Annals of Occupational Hygiene
• Published: 2006;50(8):765-75
• Cited by: 11 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A method for a semi-quantitative retrospective assessment of exposure to trichloroethylene (TCE) was implemented for a case-control study conducted in the Arve valley (France), an area with a widely developed screw-cutting industry, where teams of occupational physicians have collected a large quantity of well-documented measurements. A task-exposure matrix was developed to link the main working circumstances in a screw-cutting workshop to corresponding TCE-exposure levels: a 'basic level' was assigned to each task, standing for usual working procedures; exposure circumstances, such as duration or distance from the TCE source, were introduced as corrective factors. In parallel, a detailed occupational questionnaire was designed, setting subjects' descriptions of their successive jobs and working circumstances against levels assessed in the matrix. Possible exposure to TCE, plus some other occupational compounds (other solvents, oils, some metals, asbestos, welding fumes and ionizing radiations), were assessed for any job in all job histories. An average level of exposure to TCE, related to an 8 h usual working day, was attributed to each job period in turn, which was then categorized into six classes: 0; 1-35; 35-50; 50-75; 75-100; and >100 p.p.m. A total of 402 study subjects described their occupational life (average 3.7 jobs/subject, from 1924 to 2003). About 19% of the 1486 job periods described were assessed as being exposed to TCE; of these, 72.2% involved levels<35 p.p.m., 13.2% involved levels>50 p.p.m. and 5.4% above the French occupational exposure limit of 75 p.p.m. (TWA 8 h). A total of 41 job periods included exposure with peaks. Compared with levels encountered in other studies, the more severely exposed part of our study population seemed more exposed than most other populations previously studied, owing to vapor degreasing practices.

In plain English

This was Part I of a hospital-based case-control study of renal cell cancer in France's Arve Valley, a screw-cutting area. It described how past workplace exposure to the solvent trichloroethylene (TCE) was estimated; it did not report cancer risks. The 402 subjects (86 cases, 316 controls) described 1341 jobs in questionnaires; the authors split some, giving 1486 job periods. These were combined with a task-exposure matrix built from local air and urine measurements. Other exposures, including asbestos, were rated only low, medium or high. Asbestos was assigned to 164 job periods (11.0%), 143 of them at the low level. TCE exposure was assigned to 295 job periods (19%). Expressed as 8-hour averages, 72.2% of these were below 35 p.p.m., 13.2% above 50 p.p.m., and 5.4% above the French occupational exposure limit of 75 p.p.m. The number of TCE-exposed job periods was highest in the 1970s. Local occupational physicians agreed with the authors' ratings for 23 of 32 job periods checked. The authors concluded their population could not be regarded as a typical general population. They called their distance corrections very crude estimates.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Exposure-assessment methods paper (Part I) for a hospital-based case-control study of renal cell cancer; does not report cancer risk results
• Who was studied: 402 subjects (86 renal cell cancer cases and 316 controls) in the Arve Valley, France. They described 1341 jobs held between 1924 and 2003, which the authors split into 1486 job periods.
• Exposure: Mainly trichloroethylene (TCE), estimated as 8-hour average levels with a task-exposure matrix. Other solvents, oils, some metals, asbestos, welding fumes and ionizing radiation were also assessed, and these other exposures were rated only qualitatively (low, medium or high).
• Main results:
  • Asbestos exposure was assessed for 164 of the 1486 job periods (11.0%): 143 (9.6%) low, 20 (1.3%) medium, 1 (0.1%) high
  • 295 of 1486 job periods (19%) were assessed as TCE-exposed; 120 of these were outside the screw-cutting industry
  • Of the 295 TCE-exposed job periods, 72.2% were below 35 p.p.m., 13.2% above 50 p.p.m. and 5.4% above the French occupational exposure limit of 75 p.p.m. (8-hour time-weighted average)
  • 41 job periods included exposure peaks; all but one of the highest exposure levels and peaks occurred before 1980
  • The number of TCE-exposed job periods was highest in the 1970s (146, or 19.8% of job periods). The share fell to 14.8% in the 1980s and 7.1% in the 1990s.
  • Local occupational physicians independently assessed 32 screw-cutting job periods and agreed with the authors' assessment for 23 (72%)
• The authors' conclusion: The authors concluded that, with 13.2% of exposed jobs above 50 p.p.m. and frequent peaks, their study population could not be regarded as a typical general population
• Limitations the authors state:
  • The corrections for distance from the TCE source were very crude estimates, because many parameters such as ventilation were not available
  • Unusual tasks outside screw-cutting were harder for subjects to describe, so their exposure may have been underestimated or overestimated
  • Additional skin uptake during peaks could not be quantified, so peaks were not given numerical levels

Topics

Medical terms in this study, explained in our Lexicon: Case-Control Study, Occupational Exposure, Standing.

Related studies

• Occupational risk factors for renal cell carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter urothelial and renal cancer study — B. Pesch, J. Haerting, et al. (2000)
• Occupational risk factors for renal cell cancer: a case--control study in northern Italy — S. Mattioli, D. Truffelli, et al. (2002)
• Occupational exposure to dusts and risk of renal cell carcinoma — S. Karami, P. Boffetta, et al. (2011)
• International renal-cell cancer study. IV. Occupation — J.S. Mandel, J.K. McLaughlin, et al. (1995)
• Renal cell carcinoma — P.A. Godley, M.A. Escobar (1998)
• Carbonic anhydrase IX is expressed in mesothelioma and metastatic clear cell renal cell carcinoma of the lung — M.L. Ramsey, B.J. Yuh, et al. (2012)

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