Study of occupational lung cancer in asbestos factories in China

Our plain-English summary of Study of occupational lung cancer in asbestos factories in China, by R.W. Morgan, K.E. Zhao (Occupational and Environmental Medicine, 1994).

The study

• Authors: R.W. Morgan, K.E. Zhao
• Journal: Occupational and Environmental Medicine
• Published: 1994;51(10):719
• Type of article: Comment, Letter
• Read it: PubMed · Publisher · Free full text

In plain English

This item was a letter to the editor, not a research study. The authors questioned findings in a 1993 article by Huilan and Zhiming on occupational lung cancer in asbestos factories in China. They noted that table 6 of that article showed 19 of 57 lung cancer cases (33%) among non-smokers. They called this very high, since most series find under 10%. They asked why table 6 listed 57 lung cancers when the text reported 67 (including two pleural mesotheliomas). They observed that lung cancer incidence in women was under half that in men, apparently without adjustment for age or smoking. Their main concern was a relative risk of only 1.8 for smokers without asbestos exposure, against usual values of 5 to 25. The authors concluded this raised serious questions about the credibility of any of the findings. In a reply printed alongside, the original article's author, Huilan Zhu, said table 6 used data from seven factories only. The reply suggested that lower cigarette consumption in China before 1982 might explain the low figure.

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 (correspondence) commenting on a previously published study; no new data were collected
• Who was studied: No population was studied by the letter's authors; the letter discusses the lung cancer cases reported in Huilan and Zhiming's 1993 study of asbestos factories in China (Br J Ind Med 1993;50:1039-42)
• Exposure: Work in asbestos factories in China, as studied in the earlier article; no fiber types are named in the letter. Smoking is also discussed.
• Main results:
  • The letter pointed out that table 6 of the earlier study showed 19 of 57 (33%) lung cancer cases among non-smokers. The authors called this very high, since in most series less than 10% of cases occur in non-smokers.
  • The letter noted that the earlier study's text reported 67 lung cancers (including two pleural mesotheliomas), but table 6 showed only 57.
  • The letter noted that table 3 of the earlier study showed lung cancer incidence in women less than half that of men, with rates apparently not adjusted for age or smoking. The authors argued that male and female rates ought to be closer if asbestos caused a high percentage of the lung cancers.
  • The letter noted that table 6 of the earlier study gave a lung cancer relative risk of only 1.8 for smokers without asbestos exposure. The authors compared this with usual relative risks of 5 to 25 for populations of smokers.
  • In the printed reply, the original study's author said that 15 of the 19 non-smoking lung cancer cases were exposed to asbestos, so four cases were neither exposed to asbestos nor smoked.
  • In the reply, the original study's author said table 6 used data from only seven factories, because smoking questions were not asked in the control groups of the eighth asbestos factory.
  • In the reply, the original study's author said the relative risk of 1.8 for smoking alone was lower than expected. The author suggested this might be due to much lower average cigarette consumption before 1982 in China than in some western countries.
• The authors' conclusion: The letter's authors concluded that a study finding a relative risk this low for smokers raises serious questions about the credibility of any of its findings.

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: Lung Cancer.

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• Epidemiology of occupational asbestos-related diseases in China — S.X. Cai, C.H. Zhang, et al. (2001)
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