Occupational exposure and laryngeal and hypopharyngeal cancer risk in central and eastern Europe

Our plain-English summary of Occupational exposure and laryngeal and hypopharyngeal cancer risk in central and eastern Europe, by O. Shangina, P. Brennan, N. Szeszenia-Dabrowska, et al (American Journal of Epidemiology, 2006).

The study

• Authors: O. Shangina, P. Brennan, N. Szeszenia-Dabrowska, D. Mates, E. Fabiánová, T. Fletcher, A. t'Mannetje, P. Boffetta, D. Zaridze
• Journal: American Journal of Epidemiology
• Published: 2006;164(4):367-75
• Cited by: 76 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A multicenter case-control study was conducted during 1999-2002 in four European countries (Poland, Romania, Russia, and Slovakia) to evaluate the role of occupational exposures in risk of laryngeal/hypopharyngeal cancer. Male cancer cases (34 hypopharyngeal, 316 laryngeal) with full data on occupational history and nonoccupational factors were compared with 728 hospital controls for occupational exposure to 73 suspected carcinogens. Occupational history was evaluated by industrial hygienists blinded to case/control status. Elevated risks for ever exposure to coal dust were found for both hypopharyngeal (odds ratio (OR) = 4.19, 95% confidence interval (CI): 1.18, 14.89) and laryngeal (OR = 1.81, 95% CI: 0.94, 3.47) cancer, with clear dose-response patterns. Inclusion of a 20-year lag in the analysis strengthened these associations. Hypopharyngeal cancer risk was also significantly associated with exposure to mild steel dust (OR = 3.04, 95% CI: 1.39, 6.64) and iron compounds and fumes (OR = 2.74, 95% CI: 1.29, 5.84), without clear dose-response relations. Laryngeal cancer was significantly associated with exposure to hard-alloys dust (OR = 2.23, 95% CI: 1.08, 4.57) and chlorinated solvents (OR = 2.18, 95% CI: 1.03, 4.61), without dose-response relations. A possible link between high formaldehyde exposure and laryngeal cancer was suggested. No association was found for exposure to asbestos or inorganic acid mists. These data indicate that occupational exposure to coal dust may play a role in laryngeal and hypopharyngeal cancer. Other possible relations need further evaluation.

In plain English

This multicenter case-control study was run in 1999–2002 at centers in Poland, Romania, Russia and Slovakia. It compared 34 men with hypopharyngeal cancer and 316 men with laryngeal cancer with 728 male hospital controls. Experts who did not know who was a case rated each man's jobs for exposure to 73 agents. Results were adjusted for age, country, smoking and alcohol. For laryngeal cancer, the odds ratio for ever exposure to asbestos in general was 0.86 (95% CI 0.51 to 1.45), and for chrysotile asbestos it was 0.78 (0.44 to 1.40). The authors found no association between any form of asbestos and these cancers. For laryngeal cancer, ever exposure to coal dust gave an odds ratio of 1.81 (0.94 to 3.47), which was not statistically significant, though risk rose with exposure. The authors said these associations were seen only in Poland. For hypopharyngeal cancer, the coal-dust odds ratio was 4.19 (1.18 to 14.89), based on only four exposed cases. The authors concluded that coal dust was associated with both cancers and that several other links need further evaluation. They noted that interviewers knew who was a case.

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: Multicenter hospital-based case-control study
• Who was studied: Men only: 34 with hypopharyngeal cancer, 316 with laryngeal cancer, and 728 male hospital controls, from centers in Poland, Romania, Russia and Slovakia, 1999–2002
• Exposure: Occupational exposure to 73 agents or groups of agents, including asbestos in general and chrysotile asbestos, assessed by experts from job histories
• Main results:
  • Laryngeal cancer, asbestos (general exposure): 65 exposed controls, 26 exposed cases, odds ratio 0.86 (95% CI 0.51, 1.45)
  • Laryngeal cancer, chrysotile asbestos: 54 exposed controls, 21 exposed cases, odds ratio 0.78 (95% CI 0.44, 1.40)
  • The authors observed no association between any form of asbestos and laryngeal or hypopharyngeal cancer
  • Laryngeal cancer, coal dust: 24 exposed controls, 26 exposed cases, odds ratio 1.81 (95% CI 0.94, 3.47)
  • For laryngeal cancer, only coal dust showed a clear dose-response pattern. The authors said the association was statistically significant only after a 20-year lag was included
  • The laryngeal cancer associations with coal dust were observed only for Poland, not the other countries
  • Hypopharyngeal cancer, coal dust: odds ratio 4.19 (95% CI 1.18, 14.89), based on only four exposed cases
  • Hypopharyngeal cancer, mild steel dust: 165 exposed controls, 14 exposed cases, odds ratio 3.04 (95% CI 1.39, 6.64)
  • Hypopharyngeal cancer, iron compounds and fumes: 180 exposed controls, 19 exposed cases, odds ratio 2.74 (95% CI 1.29, 5.84)
  • Laryngeal cancer, hard-alloys dust: odds ratio 2.23 (95% CI 1.08, 4.57). Chlorinated solvents: odds ratio 2.18 (95% CI 1.03, 4.61). No dose-response patterns were seen for either
  • Laryngeal cancer, formaldehyde: odds ratio 3.12 (95% CI 1.23, 7.91) at the highest level of cumulative exposure. There was no overall association
• The authors' conclusion: The authors concluded that the study showed an association between coal dust exposure and laryngeal and hypopharyngeal cancer. They said the other associations need further evaluation.
• Limitations the authors state:
  • Interviewers knew whether a subject was a case or a control, so interviewer bias cannot be excluded. The authors judged it probably not a major limitation because the expert assessors were blinded.
  • Some exposure misclassification is expected, which could weaken (attenuate) the odds ratios
  • The study may have lacked statistical power to detect moderate effects
  • Women were excluded because there were too few female cases

Topics

The National Library of Medicine indexes this study under subjects our site covers: Throat and laryngeal cancer.

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Case-Control Study, Occupational History, Odds Ratio, confidence interval, Dose-response relationship, Laryngeal Cancer.

Related studies

• Laryngeal and hypopharyngeal cancer and occupational exposure to asbestos and man-made vitreous fibers: results of a case-control study — J.L. Marchand, D. Luce, et al. (2000)
• Occupational exposure to polycyclic aromatic hydrocarbons and lung cancer risk: a multicenter study in Europe — A.C. Olsson, J. Fevotte, et al. (2010)
• Occupational exposure to asbestos and man-made vitreous fibres and risk of lung cancer: a multicentre case-control study in Europe — R. Carel, A.C. Olsson, et al. (2007)
• Occupation and larynx and hypopharynx cancer: a job-exposure matrix approach in an international case-control study in France, Italy, Spain and Switzerland — F. Berrino, L. Richiardi, et al. (2003)
• Exposure to cement dust, related occupational groups and laryngeal cancer risk: results of a population based case-control study — A. Dietz, H. Ramroth, et al. (2004)
• A case-control study of occupational risk factors for laryngeal cancer — P. Wortley, T.L. Vaughan, et al. (1992)

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