Occupational exposure to wood dust and risk of lung cancer: the ICARE study

Our plain-English summary of Occupational exposure to wood dust and risk of lung cancer: the ICARE study, by M. Matrat, L. Radoï, J. Févotte, et al (Occupational and Environmental Medicine, 2019).

The study

• Authors: M. Matrat, L. Radoï, J. Févotte, F. Guida, S. Cénée, D. Cyr, M. Sanchez, G. Menvielle, A. Schmaus, E. Marrer, D. Luce, I. Stücker, ICARE Study Group
• Journal: Occupational and Environmental Medicine
• Published: 2019;76(12):901-907
• Cited by: 6 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: In a previous analysis of data from a French population-based case-control study (the Investigation of occupational and environmental CAuses of REspiratory cancers (ICARE) study), 'having ever worked' in wood-related occupations was associated with excess lung cancer risk after adjusting for smoking but not for occupational factors. The present study aimed to investigate the relationship between lung cancer risk and wood dust exposure after adjusting for occupational exposures.

Methods: Data were obtained from 2276 cases and 2780 controls on smoking habits and lifelong occupational history, using a standardised questionnaire with a job-specific questionnaire for wood dust exposure. Logistic regression models were used to calculate ORs and 95% CIs adjusted for age, area of residence, tobacco smoking, the number of job periods and exposure to silica, asbestos and diesel motor exhaust (DME).

Results: No significant association was found between lung cancer and wood dust exposure after adjustment for smoking, asbestos, silica and DME exposures. The risk of lung cancer was slightly increased among those who were exposed to wood dust more than 10 years, and had over 40 years since the first exposure.

Conclusion: Our findings do not provide a strong support to the hypothesis that wood dust exposure is a risk factor for lung cancer. This study showed the importance of taking into account smoking and occupational coexposures in studies on lung cancer and wood dust exposure. Further studies evaluating the level and frequency of exposure during various tasks in woodwork are needed.

© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.

In plain English

This French population-based case-control study, part of the ICARE study (10 areas, 2001 to 2007), examined whether on-the-job wood dust exposure was linked to lung cancer. It included 2276 men with lung cancer and 2780 men without; women were excluded because only 14 were exposed. Adjusted for age, area, number of jobs and smoking, ever-exposure was linked to higher odds of lung cancer (OR 1.29, 95% CI 1.06 to 1.56). When further adjusted for workplace asbestos, silica and diesel motor exhaust, the link was not statistically significant (OR 1.13, 95% CI 0.86 to 1.48). Duration and timing were assessed only in the 153 cases and 166 controls who answered a detailed wood-dust questionnaire, which was given to men exposed over 5% of their worktime in a job. In that group, raised risks for over 10 years of exposure and over 40 years since first exposure also lost statistical significance after the extra adjustment. Men in this group who only sawed wood had an OR of 3.30 (95% CI 1.26 to 8.66) after that adjustment. The authors concluded that their findings do not strongly support wood dust as a lung cancer risk factor.

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: Multicentre population-based case-control study (the ICARE study)
• Who was studied: Men only: 2276 lung cancer cases and 2780 population controls from 10 French 'départements', 2001 to 2007. Women were excluded because only 14 were exposed to wood dust.
• Exposure: Self-reported occupational wood dust exposure. Participants exposed for more than 5% of their worktime answered a job-specific questionnaire on wood species (hardwood, softwood, composite, exotic) and tasks (sanding, sawing, manual or mechanical). Analyses were also adjusted for asbestos (task-exposure matrix index), silica and diesel motor exhaust.
• Main results:
  • 390 cases and 447 controls had ever been exposed to wood dust.
  • Ever exposed to wood dust, all men: OR 1.29 (95% CI 1.06 to 1.56) adjusted for age, area, number of jobs and smoking. OR 1.13 (95% CI 0.86 to 1.48) when further adjusted for asbestos, silica and diesel motor exhaust.
  • Duration of exposure and time since first exposure were assessed only among the 166 controls and 153 cases who completed the specific wood-dust questionnaire.
  • In that questionnaire group, increased risks for exposure over 10 years (OR 1.51, 95% CI 1.03 to 2.22) and over 40 years since first exposure (OR 1.60, 95% CI 1.07 to 2.40) were no longer statistically significant after adjustment for asbestos, silica and diesel motor exhaust (OR 1.29, 95% CI 0.79 to 2.13, and OR 1.47, 95% CI 0.89 to 2.43).
  • Among the questionnaire group, workers who only sawed (32 cases, 27 controls): OR 1.92 (95% CI 0.98 to 3.77) without adjustment for coexposures, and OR 3.30 (95% CI 1.26 to 8.66) with it. Workers who only sanded were too few to draw conclusions.
  • The association did not differ by histological type: OR 1.11 (95% CI 0.66 to 1.86) for adenocarcinoma and OR 1.10 (95% CI 0.66 to 1.85) for squamous cell carcinoma, both adjusted for occupational exposures.
  • Odds ratios were not higher among men who worked indoors or had no suction system.
  • Odds ratios were similar for the different wood types and not statistically significant after adjustment for occupational factors. Most exposed men (74%) had been exposed to both hardwood and softwood.
• The authors' conclusion: The authors concluded that their results do not provide strong support for the hypothesis that wood dust exposure is a risk factor for lung cancer. They also concluded that the study shows the importance of accounting for coexposures to other occupational carcinogens.
• Limitations the authors state:
  • Wood dust exposure was self-reported, so over-reporting by cases could not be fully ruled out.
  • The level of wood dust exposure was not available.
  • The authors could not isolate exposure to a single wood species because few workers had such exposure.
  • There was no information on airborne dust from cleaning machines with compressed air.

Topics

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

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Lung Cancer, Case-Control Study, Habit, Occupational History.

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