In reference to Asbestos exposure and laryngeal cancer mortality

Our plain-English summary of In reference to Asbestos exposure and laryngeal cancer mortality, by M.M. Finkelstein (The Laryngoscope, 2017).

The study

• Author: M.M. Finkelstein
• Journal: The Laryngoscope
• Published: 2017;127(3):E114
• Type of article: Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a letter to the editor, not a new study of workers. The author re-ran a 2016 meta-analysis by Peng and colleagues, which pooled studies of asbestos exposure and deaths from laryngeal (voice box) cancer. According to the author, that meta-analysis left out a 1997 study by Liddell and colleagues of some 11,000 Canadian chrysotile miners. That study reported 30 laryngeal cancer deaths and a standardized mortality ratio (SMR), which compares observed deaths with expected deaths, of 1.04. In the re-analysis the Canadian study carried 14.6% of the weight. Adding it lowered the pooled SMR from 1.69 (95% CI 1.45–1.97) to 1.56 (95% CI 1.35–1.80). The pooled SMR stayed significantly elevated, and there was still no significant variation between studies. The author also compared fiber types, using chrysotile as the baseline. The relative SMR was 1.22 (95% CI 0.85–1.75, P 0.26) for mixed chrysotile and amphibole, and 1.57 (95% CI 0.96–2.56, P 0.07) for crocidolite. The author concluded that including the Canadian study gave a more complete result but did not substantially change Peng and colleagues' findings.

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: Letter to the editor reporting an updated random-effects meta-analysis: one cohort study was added to a previously published meta-analysis, followed by a meta-regression by fiber type
• Who was studied: The studies listed in Table I of Peng and colleagues' 2016 meta-analysis (the letter does not say how many), plus the 1997 Liddell and colleagues cohort of some 11,000 Quebec chrysotile miners (and millers, per the cited title) followed for mortality
• Exposure: Asbestos exposure in the pooled cohorts, grouped by fiber type: chrysotile, mixed chrysotile and amphibole, and crocidolite
• Main results:
  • The added Canadian study (Liddell and colleagues) had reported 30 laryngeal cancer deaths and an SMR of 1.04 among the chrysotile miners
  • The Canadian study contributed 14.6% of the weighted data in the model, second only to the 24.9% from the English study of Harding and colleagues
  • Adding the Canadian study lowered the pooled laryngeal cancer SMR from 1.69 (95% CI 1.45–1.97, Peng et al.) to 1.56 (95% CI 1.35–1.80, updated), described as an 8% effect
  • The updated pooled SMR remained significantly elevated, and there was still no significant heterogeneity among studies (updated Q 18.7, I2 0.0%)
  • Compared with chrysotile as baseline (1.0), the relative pooled laryngeal cancer SMR was 1.22 (95% CI 0.85–1.75, P 0.26) for mixed chrysotile and amphibole
  • Compared with chrysotile as baseline, the relative pooled laryngeal cancer SMR was 1.57 (95% CI 0.96–2.56, P 0.07) for crocidolite; the letter did not comment further on these fiber-type figures
• The authors' conclusion: The author concluded that including the Canadian study produced a more complete result, but that there were no substantial changes to the findings published by Peng and colleagues

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: Asbestos Exposure, Laryngeal Cancer.

Related studies

• Chrysotile fibers in tissue adjacent to laryngeal squamous cell carcinoma in cases with a history of occupational asbestos exposure — S.K. Wronkiewicz, V.L. Roggli, et al. (2020)
• Exposure to nitrosamines, carbon black, asbestos, and talc and mortality from stomach, lung, and laryngeal cancer in a cohort of rubber workers — K. Straif, U. Keil, et al. (2000)
• Asbestos exposure and laryngeal cancer mortality — W.J. Peng, J. Mi, et al. (2016)
• Diet and other risk factors for laryngeal cancer in Shanghai, China — W. Zheng, W.J. Blot, et al. (1992)
• Asbestos and laryngeal carcinoma — P.M. Stell, T. McGill (1973)
• Occupational exposure and laryngeal and hypopharyngeal cancer risk in central and eastern Europe — O. Shangina, P. Brennan, et al. (2006)

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