Lung cancer mortality among asbestos textile workers: a review and update

Our plain-English summary of Lung cancer mortality among asbestos textile workers: a review and update, by J.M. Dement, D.P. Brown (The Annals of Occupational Hygiene, 1994).

The study

• Authors: J.M. Dement, D.P. Brown
• Journal: The Annals of Occupational Hygiene
• Published: 1994;38(4):525-32, 412
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

In an update of the mortality of the cohort of 1200 South Carolina textile workers, of whom almost half died, there were 185 excess deaths (SMR = 1.44), which included 71 cardiovascular diseases (SMR = 1.37), 43 non-malignant respiratory diseases (SMR = 2.25) and 41 lung cancers (SMR = 2.25). Only two definite mesotheliomas were observed. Other possible cases may have occurred but no confirmatory pathology was available. Strong exposure-response relationships have been found for lung cancer and for non-malignant respiratory diseases. The data suggest a doubling of the lung cancer risk at an exposure of approximately 30 fibre years. Mortality from pneumoconiosis and other respiratory diseases was elevated at even the lowest cumulative exposure category (< 2 f ml-1 years). A nested case-control analysis failed to demonstrate a significant role for mineral oil exposure in the etiology of lung cancer. Differences in airborne fibre sizes may be important in explaining different lung cancer and pneumoconiosis risks in various industries. In particular, the data on airborne fibres in textile manufacturing industries suggested 11-27% were longer than 5 microns compared to 2-5% for mining and milling.

In plain English

This paper gave preliminary results from an updated mortality study, followed to the end of 1990. It covered white men who worked in textile production at a South Carolina plant that processed chrysotile asbestos. The authors also compared their findings with other asbestos textile cohorts. Of 1247 men, 607 had died. Deaths from all causes exceeded expectations based on U.S. death rates (SMR 1.44, 90% confidence interval 1.35-1.54). There were 74 lung cancer deaths (SMR 2.24, 90% CI 1.83-2.72) and 58 deaths from non-malignant respiratory disease (SMR 2.24, 90% CI 1.78-2.79). Two death certificates recorded mesothelioma, one pleural and one peritoneal. Among men with at least 15 years of latency, lung cancer risk rose with cumulative exposure, reaching an SMR of 10.00 (2 deaths observed, 0.2 expected) above 100000 fibres per cm3-days. A nested case-control analysis found no significant change in this exposure-response after adjusting for mineral oil exposure. The authors suggested that lung cancer risk estimates from chrysotile mining and milling would be inappropriate for industries using chrysotile, as the true risk could be greatly underestimated.

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: Update of a retrospective cohort mortality study, with a nested case-control analysis of lung cancer and mineral oil, plus a comparison with other asbestos textile cohorts
• Who was studied: 1247 white male workers employed at least 1 month in textile production at a South Carolina asbestos plant between 1 January 1940 and 31 December 1965. Vital status was followed to 31 December 1990, and 607 had died.
• Exposure: Chrysotile asbestos from Quebec, British Columbia and Rhodesia, the only asbestos processed as raw fibre at the plant. Exposure was measured as cumulative fibres (longer than 5 micrometres) per cm3-days. Mineral oil used in textile processing was assessed qualitatively.
• Main results:
  • All causes of death in the cohort (607 deaths): SMR 1.44, 90% confidence interval 1.35-1.54, compared with U.S. rates
  • All respiratory tract cancer: SMR 2.25 (90% CI 1.85-2.71), mainly lung cancer. The table lists 74 deaths from trachea, bronchus and lung cancer, SMR 2.24 (1.83-2.72).
  • Non-malignant respiratory disease (58 deaths): SMR 2.24 (90% CI 1.78-2.79). Pneumoconiosis was the underlying cause in 21 of the 41 deaths from pneumoconiosis and other respiratory disease.
  • An unexpected, statistically significant excess of liver, gall bladder and biliary tract cancer (6 deaths): SMR 4.04 (90% CI 1.76-7.97)
  • Mesothelioma (one pleural, one peritoneal) was recorded on the death certificates of two white males employed 25 and 32 years. One further death from 'cancer of the pleura' did not mention mesothelioma.
  • Among cohort members with at least 15 years of latency, lung cancer risk increased with cumulative exposure. It first became statistically significant at 1000-2500 fibres per cm3-days (15 observed vs 6.2 expected, SMR 2.42).
  • Among cohort members with at least 15 years of latency, the highest exposure group (over 100000 fibres per cm3-days) had a lung cancer SMR of 10.00, based on 2 observed vs 0.2 expected deaths.
  • In the nested case-control analysis, the lung cancer odds ratio for 40000 or more fibres per cm3-days was 7.33 without and 7.74 with control for mineral oil exposure. There was no significant change in the exposure-response slope.
• The authors' conclusion: The authors concluded that the update confirmed a steep lung cancer exposure-response and that mineral oil's contribution appeared insignificant. They wrote that the results suggest lung cancer risk estimates from chrysotile mining and milling would be inappropriate for chrysotile user industries, because the true risk could be greatly underestimated.
• Limitations the authors state:
  • The authors describe the results as preliminary

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestos textiles, Asbestosis, Chrysotile, Lung cancer.

Medical terms in this study, explained in our Lexicon: Lung Cancer, Mesothelioma, Pathology, Pneumoconiosis, Cumulative Exposure, Etiology.

Related studies

• Follow-up study of chrysotile asbestos textile workers: cohort mortality and case-control analyses — J.M. Dement, D.P. Brown, et al. (1994)
• Increased lung cancer mortality among chrysotile asbestos textile workers is more strongly associated with exposure to long thin fibres — D. Loomis, J.M. Dement, et al. (2012)
• Lung cancer mortality in North Carolina and South Carolina chrysotile asbestos textile workers — L. Elliott, D. Loomis, et al. (2012)
• Cause-specific mortality in a Chinese chrysotile textile worker cohort — X. Wang, S. Lin, et al. (2013)
• Cancer mortality among Chinese chrysotile asbestos textile workers — X.R. Wang, I.T. Yu, et al. (2012)
• Multistage modelling of lung cancer mortality in asbestos textile workers — N. Pearce (1988)

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