Nonmalignant respiratory disease mortality among woodworkers participating in the American Cancer Society Cancer Prevention Study-II (CPS-II)

Our plain-English summary of Nonmalignant respiratory disease mortality among woodworkers participating in the American Cancer Society Cancer Prevention Study-II (CPS-II), by P.A. Demers, S.D. Stellman, D. Colin, et al (American Journal of Industrial Medicine, 1998).

The study

• Authors: P.A. Demers, S.D. Stellman, D. Colin, P. Boffetta
• Journal: American Journal of Industrial Medicine
• Published: 1998;34(3):238-43
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Nonmalignant respiratory disease (NMRD) mortality was examined among woodworkers participating in the American Cancer Society's CPS-II cohort study. During the 6-year prospective follow-up there were 97 NMRD death's among 11,541 men reporting employment in wood-related occupations and 1,338 NMRD deaths among 317,424 men reporting no exposure to wood dust or wood-related jobs. Relative risks, adjusted for age and smoking, were calculated using Poisson regression. A small excess of NMRD was observed among woodworkers. However, the relative risk was higher among woodworkers who did not report exposure to wood dust (RR = 1.52, 95% CI = 1.18-1.97) than those who did (RR = 1.27, 95% CI = 0.91-1.77), and no clear trend with duration of exposure was observed. An excess of NMRD was observed among woodworkers reporting exposure to asbestos (RR = 1.59, 95% CI = 0.85-2.96), as well as the small number of woodworkers reporting exposure to formaldehyde (RR = 1.95, 95% CI = 0.63-6.06), but men not reporting exposure to these substances also had an excess risk. Although limited by a short follow-up period and crude indicators of exposure, the strengths of this analysis were the ability to compare woodworkers to a similar, healthy population and to adjust for the effects of smoking. Cohort studies with better exposure information are needed to examine the role of occupational exposures among woodworkers in the etiology of respiratory disease.

In plain English

This prospective cohort analysis used the American Cancer Society's Cancer Prevention Study II, begun in 1982. Over about 6 years, the authors compared deaths from nonmalignant (non-cancer) respiratory disease between 11,541 men reporting wood-related jobs and 317,424 men reporting neither wood jobs nor wood dust exposure. The analysis was adjusted for age and smoking. Woodworkers had 97 such deaths and the comparison group had 1,338, giving a rate ratio of 1.42 (95% CI 1.15–1.74). Compared with other blue-collar workers, the ratio was 1.15 (0.91–1.44). Compared with the 317,424 non-woodworkers, woodworkers reporting asbestos exposure had a ratio of 1.59 (0.85–2.96), and woodworkers not reporting it also had an excess (1.43, 1.15–1.77). The excess was not higher among men reporting wood dust exposure, and no clear trend with duration of wood dust exposure was seen. The authors concluded that woodworkers had a clear excess of these deaths, but that it did not appear closely related to self-reported wood dust, asbestos or formaldehyde exposure. They noted possible recall bias from the short follow-up, and that self-reported exposure data may be of low reliability.

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: Prospective cohort study: an analysis of men in the American Cancer Society's Cancer Prevention Study II, with rate ratios adjusted for age and smoking
• Who was studied: 11,541 U.S. men who reported a wood-related job as their current, last, or longest-held occupation, compared with 317,424 men who reported no wood-related job and no wood dust exposure; about 6 years of follow-up
• Exposure: Employment in wood-related occupations. Self-reported exposure (from a questionnaire checklist) to wood dust, asbestos (no fiber type given) and formaldehyde
• Main results:
  • Compared with the non-woodworker reference group, woodworkers had a rate ratio for all nonmalignant respiratory disease deaths of 1.42 (95% CI 1.15–1.74)
  • Compared with other blue-collar workers, woodworkers' rate ratio for nonmalignant respiratory disease was 1.15 (95% CI 0.91–1.44)
  • Among woodworkers, compared with the non-woodworker reference group, the rate ratio was higher for those who did not report wood dust exposure (1.52, 95% CI 1.18–1.97) than for those who did (1.27, 95% CI 0.91–1.77)
  • Compared with the non-woodworker reference group, woodworkers reporting asbestos exposure had a rate ratio for respiratory disease deaths of 1.59 (95% CI 0.85–2.96). Woodworkers not reporting asbestos exposure had a rate ratio of 1.43 (95% CI 1.15–1.77)
  • The exposure-specific comparisons all used the same reference group of 317,424 men who reported neither a wood occupation nor regular wood dust exposure
  • Ten woodworkers who reported asbestos exposure died of respiratory disease
  • Among woodworkers reporting asbestos exposure, risks of obstructive lung disease and of the 'other' respiratory disease category (which includes asbestosis) were higher, but these were based on small numbers of cases
  • The small number of woodworkers reporting formaldehyde exposure had a rate ratio of 1.95 (95% CI 0.63–6.06)
  • No clear association was seen with duration of wood dust exposure. In the longest-duration category (20 or more years), the rate ratio was 1.37 (95% CI 0.92–2.06)
  • Adjusting for whether men reported being sick when surveyed slightly reduced the risk estimates
• The authors' conclusion: The authors concluded that woodworkers had a clear excess of nonmalignant respiratory disease deaths. In their view, the excess did not appear closely related to self-reported wood dust, asbestos or formaldehyde exposure
• Limitations the authors state:
  • Recall bias was possible because the follow-up period was short
  • Self-reported checklist exposure data may have low validity and reliability
  • There were no detailed job descriptions or complete work histories

Topics

Medical terms in this study, explained in our Lexicon: Cohort Study, Relative Risk, Occupational Exposure, Etiology.

Related studies

• Cancer mortality and wood dust exposure among participants in the American Cancer Society Cancer Prevention Study-II (CPS-II) — S.D. Stellman, P.A. Demers, et al. (1998)
• Dose-response associations of silica with nonmalignant respiratory disease and lung cancer mortality in the diatomaceous earth industry — H. Checkoway, N.J. Heyer, et al. (1997)
• Cancer mortality among woodworkers — S.D. Stellman, L. Garfinkel (1984)
• Re: "Dose-response associations of silica with nonmalignant respiratory disease and lung cancer mortality in the diatomaceous earth industry" — G.W. Gibbs (1998)
• Re: "Dose-response associations of silica with nonmalignant respiratory disease and lung cancer mortality in the diatomaceous earth industry" — M.J. Mirliss (1998)
• Role of chest computed tomography in prevention of occupational respiratory disease: review of recent literature — D.N. Weissman (2015)

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