Occupational dust exposure and head and neck squamous cell carcinoma risk in a population-based case-control study conducted in the greater Boston area

Our plain-English summary of Occupational dust exposure and head and neck squamous cell carcinoma risk in a population-based case-control study conducted in the greater Boston area, by S.M. Langevin, M.D. McClean, D.S. Michaud, et al (Cancer Medicine, 2013).

The study

• Authors: S.M. Langevin, M.D. McClean, D.S. Michaud, M. Eliot, H.H. Nelson, K.T. Kelsey
• Journal: Cancer Medicine
• Published: 2013;2(6):978-86
• Cited by: 24 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Head and neck cancers account for an estimated 549,000 global cancer diagnoses each year. While tobacco use, alcohol consumption, and HPV16 infection are considered to be the major risk factors for this disease, occupational risk factors, including exposure to asbestos, have also been described, although dust exposures other than asbestos have been historically understudied. We have investigated the relationship between occupational exposures to five types of dusts, including sawdust, concrete dust, leather dust, metal dust, and chimney soot, and head and neck squamous cell carcinomas (HNSCC) in the greater Boston area. We report findings from a population-based case-control study involving 951 incident HNSCC cases and 1193 controls, frequency matched on age (±3 years), sex, and town/neighborhood of residence. Multivariable logistic regression was used to assess the association between occupational exposure to each type of dust and HNSCC, overall and by primary tumor site. After adjusting for age, sex, race, smoking, alcohol consumption, education, and HPV16 serology, laryngeal carcinoma risk increased for each decade of occupational exposure to sawdust (OR = 1.2, 95% CI: 1.0, 1.3) and metal dust (OR = 1.2, 95% CI: 1.0, 1.4); and HNSCC risk increased for each decade of occupational leather dust exposure (OR = 1.5, 95% CI: 1.2, 1.9). We have provided evidence for an association between occupational sawdust and metal dust and laryngeal squamous cell carcinoma, and leather dust and HNSCC, with increasing risk with longer duration at the exposed occupation.

© 2013 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

In plain English

This Boston-area population-based case-control study examined whether work exposure to sawdust, concrete dust, leather dust, metal dust or chimney soot was associated with head and neck squamous cell carcinoma. It analyzed 951 cases and 1193 controls, recruited 1999 to 2003 and 2006 to 2011. Results were adjusted for age, sex, race, smoking, alcohol, education and HPV16 antibodies. Each decade of sawdust exposure was associated with higher laryngeal cancer risk (OR = 1.2, 95% CI: 1.0, 1.3). So was each decade of metal dust exposure, which the authors called borderline (OR = 1.2, 95% CI: 1.0, 1.4). Each decade of leather dust exposure was associated with higher risk of squamous cell carcinoma of the oral cavity, pharynx and larynx combined (OR = 1.5, 95% CI: 1.2, 1.9) and of the pharynx alone (OR = 1.7, 95% CI: 1.2, 2.2). Concrete dust and chimney soot showed no significant associations. Asbestos was not one of the dusts studied. Adjusting for self-reported asbestos exposure did not significantly change the sawdust or metal dust results. The authors concluded they had provided evidence for these associations.

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: Population-based case-control study, analyzed with multivariable logistic regression
• Who was studied: Incident head and neck squamous cell carcinoma cases enrolled through major Boston teaching hospitals, and controls selected from town records and frequency matched on age (within 3 years), sex and town or neighborhood. All lived in Boston or 162 nearby cities and towns. Recruitment ran from December 1999 to December 2003 and from October 2006 to June 2011. Participation was 78% for cases and 47% for controls. After excluding people with no dust responses, 951 cases (355 oral cavity, 437 pharynx, 159 larynx) and 1193 controls were analyzed.
• Exposure: Self-reported work exposure to sawdust, concrete dust, leather dust, metal dust and chimney soot, collected by questionnaire with job start and end dates. Exposure was modeled as ever versus never and by years worked in exposed jobs. Self-reported asbestos exposure was examined only as a possible confounder.
• Main results:
  • Laryngeal squamous cell carcinoma and sawdust: ever exposure gave a borderline OR = 1.4 (95% CI: 1.0, 2.2). Each decade of exposure gave OR = 1.2 (95% CI: 1.0, 1.3). A footnote gives the lower confidence limit as 1.0004 (P = 0.049).
  • Leather dust, per decade of exposure: OR = 1.5 (95% CI: 1.2, 1.9) for head and neck squamous cell carcinoma overall (oral cavity, pharynx and larynx combined), and OR = 1.7 (95% CI: 1.2, 2.2) for pharyngeal squamous cell carcinoma. Ever exposure to leather dust was not significant for head and neck squamous cell carcinoma overall (OR 1.2, 95% CI 0.7, 2.1; 40 cases and 33 controls exposed).
  • Among people exposed to leather dust, cases had worked longer in exposed jobs than controls: a median of 24 years among 37 cases versus 7 years among 26 controls (P = 0.007).
  • Laryngeal cancer and metal dust: each decade of exposure gave a borderline increase in risk, OR = 1.2 (95% CI: 1.0, 1.4).
  • No significant associations were found between concrete dust or chimney soot and head and neck squamous cell carcinoma, either overall or for any tumor site.
  • Self-reported sawdust exposure was moderately correlated with self-reported asbestos exposure (r = 0.46). Adding asbestos and other correlated exposures as covariates did not significantly alter the laryngeal cancer estimates for sawdust or metal dust (data not shown).
  • No effect modification was observed between the dust exposures and history of asthma, allergies, heavy smoking or drinking, or HPV16 serostatus.
• The authors' conclusion: The authors concluded that they had provided evidence for an association of occupational sawdust and metal dust with laryngeal squamous cell carcinoma, and of leather dust with head and neck squamous cell carcinoma, with risk increasing with longer duration in the exposed occupation.
• Limitations the authors state:
  • Exposures were self-reported, which could lead to differential misclassification or recall bias.
  • The study was underpowered to detect associations with rarer exposures, particularly by tumor site or by duration.
  • There were no data on how often or how intensely people were exposed. Duration of employment was used as a stand-in for dose.
  • Self-reported asbestos exposure was controlled for, but residual confounding could not be ruled out.

Topics

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

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