Mortality from all cancers of asbestos factory workers in east London 1933-80

Our plain-English summary of Mortality from all cancers of asbestos factory workers in east London 1933-80, by G. Berry, M.L. Newhouse, J.C. Wagner (Occupational and Environmental Medicine, 2000).

The study

• Authors: G. Berry, M.L. Newhouse, J.C. Wagner
• Journal: Occupational and Environmental Medicine
• Published: 2000;57(11):782-5
• Cited by: 70 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Objective: To give the observed and expected deaths due to cancer at all separate sites in asbestos workers in east London, and to analyse these for overall effect and exposure-response trend.

Methods: The mortality experience of a cohort of over 5000 men and women followed up for over 30 years since first exposure to asbestos has been extracted.

Results: There was a large excess of deaths due to cancer (537 observed, 222 expected). Most of these were due to cancer of the lung (232 observed, 77 expected) and pleural (52) and peritoneal (48) mesothelioma. The exposure-response trend for all these three causes was highly significant. There was also an excess of cancer of the colon (27 observed, 15 expected) which was significantly related to exposure. There were significant excesses of cancer of the ovary, of the liver, and of the oesophagus but with no consistent relation to exposure.

Conclusions: The excess risk of cancer after exposure to asbestos was mainly due to cancer of the lung and mesothelioma. An exposure related excess of cancer of the colon was also detected but the possibility that some of these deaths may have been peritoneal mesotheliomas could not be excluded. There was no consistent evidence of exposure related excesses at any other site.

In plain English

This study followed about 3000 men and 700 women from an east London asbestos factory, plus 1400 laggers (insulators) who worked on contracts outside the factory. Crocidolite was used until the mid-1950s, along with amosite and chrysotile, and much of the exposure was to mixed fiber types. The authors compared deaths from 1951 to 1980, excluding each worker's first 10 years after first employment, with numbers expected from England and Wales death rates. There were 537 cancer deaths against 221.58 expected. Lung cancer accounted for 232 deaths against 76.96 expected, and there were 52 pleural and 46 peritoneal mesotheliomas. Lung cancer, both mesothelioma types and colon cancer (27 observed, 14.78 expected) increased significantly with exposure. The colon excess occurred only in laggers and in men severely exposed for more than 2 years. Cancers of the ovary, liver and oesophagus were also in excess, but without a significant exposure trend. The authors concluded the excess was mainly lung cancer and mesothelioma. Because some colon cancer deaths might have been peritoneal mesotheliomas, they said an asbestos-related colon cancer excess could not be accepted without support from other studies.

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: Cohort mortality study comparing observed deaths with deaths expected from national (England and Wales) rates, with analysis of exposure-response trend
• Who was studied: About 3000 men and 700 women factory workers and 1400 laggers (insulators) at an east London asbestos factory. Men were first employed between May 1933 and 1964 and worked at least 30 days. Women were first employed between 1936 and 1942. Follow-up ran to June 1980 (women) and December 1980 (men). Mortality was analysed from 1951 onwards, and the first 10 years after first employment were excluded.
• Exposure: Manufacture of asbestos textiles and products such as prefabricated cement pipes. Crocidolite was used until the mid-1950s, as well as amosite and chrysotile, and much exposure was to mixed fiber types. Exposure was classified as low to moderate versus severe, and by duration (2 years or less versus more than 2 years). Laggers were kept as a separate group.
• Main results:
  • All men and women, all cancers (neoplasms): 537 observed vs 221.58 expected; observed/expected ratio 2.42 (95% CI 2.22 to 2.64)
  • All men and women, lung cancer: 232 observed vs 76.96 expected; observed/expected ratio 3.01 (95% CI 2.64 to 3.43)
  • Mesothelioma, all men and women: 52 pleural (rate 61 per 100 000 person-years, 95% CI 46 to 80) and 46 peritoneal (rate 54 per 100 000 person-years, 95% CI 40 to 72)
  • Significant trend with exposure for lung cancer (p<0.001), peritoneal mesothelioma (p<0.001), pleural mesothelioma (p=0.011) and colon cancer (p=0.017)
  • All men and women, colon cancer: 27 observed vs 14.78 expected; observed/expected ratio 1.83 (95% CI 1.20 to 2.66). The excess was confined to laggers and men severely exposed for more than 2 years.
  • Ovarian cancer: 9 observed vs 3.56 expected; ratio 2.53 (95% CI 1.16 to 4.80). The exposure trend was not significant (significance level 0.18), but there was a significant excess in women with severe exposure of more than 2 years.
  • Liver, gall and bile duct cancer: 10 observed vs 3.76 expected; ratio 2.66 (95% CI 1.28 to 4.89); exposure trend not significant (p=0.77). Oesophageal cancer: 12 observed vs 5.78 expected; ratio 2.08 (95% CI 1.07 to 3.63); exposure trend not significant (p=0.98).
  • In the lowest (low to moderate) exposure group there were 49 lung cancer deaths observed vs 29.8 expected, and 16 mesotheliomas
• The authors' conclusion: The authors concluded that the excess cancer risk after asbestos exposure was mainly due to lung cancer and mesothelioma. Because some deaths certified as colon cancer may have been peritoneal mesotheliomas, they stated that an asbestos-attributable excess of colon cancer cannot be accepted without support from other studies of asbestos workers.
• Limitations the authors state:
  • The results depend on the accuracy of cause-of-death information from death certificates.
  • Not all cancer deaths could be checked against pathology. It is not known how many of the 27 colon cancer deaths were checked.
  • Some deaths certified as colon cancer may have been peritoneal mesotheliomas.
  • For rare cancers, an excess risk is difficult to establish from a single study, and a meta-analysis is needed.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Ovarian Cancer, Peritoneal Mesothelioma.

Related studies

• Mortality of factory workers in east London 1933-80 — M.L. Newhouse, G. Berry, et al. (1985)
• Correlation between fibre content of the lung and disease in east London asbestos factory workers — J.C. Wagner, M.L. Newhouse, et al. (1988)
• Correlation between fibre content of lung and disease in east London asbestos factory workers — R.M. Rudd (1989)
• Combined effect of asbestos and smoking on mortality from lung cancer and mesothelioma in factory workers — G. Berry, M.L. Newhouse, et al. (1985)
• Predictions of mortality from mesothelial tumours in asbestos factory workers — M.L. Newhouse, G. Berry (1976)
• Mortality of workers in a French asbestos cement factory 1940-82 — A.M. Alies-Patin, A.J. Valleron (1985)

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