Occupational exposure to flour dust and the risk of head and neck cancer

Our plain-English summary of Occupational exposure to flour dust and the risk of head and neck cancer, by M. Carton, G. Menvielle, D. Cyr, et al (American Journal of Industrial Medicine, 2018).

The study

• Authors: M. Carton, G. Menvielle, D. Cyr, M. Sanchez, C. Pilorget, A.V. Guizard, I. Stücker, D. Luce, Icare Study Group
• Journal: American Journal of Industrial Medicine
• Published: 2018;61(10):869-873
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Background: To investigate the association between head and neck squamous cell cancer (HNSCC) risk and occupational exposure to flour dust in women and men, using data from ICARE, a French population-based case-control study.

Methods: The analysis included 2053 cases of HNSCC and 3507 controls. Lifelong occupational history was collected. A job-exposure matrix was used to assess exposure to flour dust. Odds-ratios (ORs) and 95% confidence intervals (CI), adjusted for smoking, alcohol drinking, and asbestos exposure, were estimated with logistic regression models.

Results: Ever exposure to flour dust was associated with elevated ORs in women (OR = 2.15, 95%CI: 1.01 4.55) and in men (OR = 1.55, 95%CI: 1.11 2.17). In women, the risk increased with the probability, the duration, and the cumulative level of exposure. No dose-response relationships were observed in men.

Conclusions: Although the results were less conclusive in men than in women, overall, these findings provide some support to the hypothesis of a role of flour dust in the occurrence of HNSCC.

© 2018 Wiley Periodicals, Inc.

In plain English

This French case-control study, using ICARE data, examined whether work exposure to flour dust was associated with squamous cell head and neck cancers. It compared 275 women and 1778 men with these cancers, diagnosed between 2001 and 2007, with 762 women and 2745 men randomly selected from the general population as controls. Flour dust exposure was estimated from each person's job history using a job-exposure matrix. Results were adjusted for age, area, smoking, alcohol and asbestos exposure. For women ever exposed to flour dust, the odds ratio was 2.15 (95% CI 1.01-4.55), and 3.15 (1.34-7.43) for women with a probability of exposure of at least 90%. For men ever exposed, it was 1.55 (1.11-2.17). In women there were some signs of risk rising with more exposure, but tests for trend were not statistically significant. In men no such pattern was seen. Asbestos was only an adjustment factor; adjusting for it raised odds ratios in men but had virtually no effect in women. The authors concluded that flour dust may increase head and neck cancer risk, with less conclusive results in men.

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: multi-center, population-based case-control study (analysis of the ICARE study), using unconditional logistic regression
• Who was studied: Squamous cell head and neck cancer cases diagnosed 2001-2007 in 10 areas of France: 275 cases and 762 controls in women, 1778 cases and 2745 controls in men (2053 cases and 3507 controls in total). Controls were randomly selected from the general population of the same areas.
• Exposure: Occupational flour dust exposure, assessed from lifetime job histories with a French job-exposure matrix giving the probability and average level (mg/m3) of exposure. Asbestos exposure was included only as an adjustment variable.
• Main results:
  • Women ever exposed to flour dust: 22 cases and 27 controls, OR 2.15 (95% CI 1.01-4.55)
  • Men ever exposed to flour dust: 122 cases and 126 controls, OR 1.55 (95% CI 1.11-2.17)
  • Women certainly exposed (probability of exposure at least 90%): 18 cases and 17 controls, OR 3.15 (95% CI 1.34-7.43)
  • Men certainly exposed: 77 cases and 83 controls, OR 1.46 (95% CI 0.97-2.20)
  • In women, there were some indications of a dose-response, particularly with cumulative exposure. The p for trend was 0.320 for duration and 0.069 for cumulative exposure, against a significance threshold of 0.05.
  • In men, no relationship was observed between head and neck cancer and duration of exposure or cumulative exposure
  • Hypopharynx cancer in women: ever exposed 4 cases, OR 5.18 (95% CI 1.26-21.22); certainly exposed 3 cases, OR 10.67 (95% CI 2.30-49.47)
  • Adjusting for asbestos exposure increased the ORs among men and had virtually no effect in women
• The authors' conclusion: The authors concluded that, although results were less conclusive in men than in women, overall their findings suggest that exposure to flour dust may increase the risk of head and neck cancer
• Limitations the authors state:
  • The job-exposure matrix was not gender specific, so differences in exposure between men and women with the same job titles were not captured
  • Residual negative confounding by other occupational exposures is possible, and likely stronger in men
  • The reference group included men in other jobs at increased risk of head and neck cancer, which may make ORs appear lower in men
  • Gender differences in risk estimates may be due to chance

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Squamous Cell Carcinoma, Case-Control Study, Occupational History, confidence interval, Asbestos Exposure, Dose-response relationship.

Related studies

• Occupational dust exposure and head and neck squamous cell carcinoma risk in a population-based case-control study conducted in the greater Boston area — S.M. Langevin, M.D. McClean, et al. (2013)
• Occupational exposure to chlorinated solvents and risk of head and neck cancer in men: a population-based case-control study in France — C. Barul, A. Fayossé, et al. (2017)
• Systematic screening for occupations and occupational exposures in head and neck squamous cell carcinoma patients — S. Deneuve, B. Charbotel, et al. (2019)
• Occupational exposure to rock wool and glass wool and risk of cancers of the lung and the head and neck: a systematic review and meta-analysis — L. Lipworth, C. La Vecchia, et al. (2009)
• Occupational exposure to wood dust and risk of lung cancer: the ICARE study — M. Matrat, L. Radoï, et al. (2019)
• Occupational exposure to textile dust and lung cancer risk: Results from the ICARE Study — S. Ben Khedher, M. Neri, et al. (2018)

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