Relationship between exposure to asbestos and pleural malignancy in Belfast

Our plain-English summary of Relationship between exposure to asbestos and pleural malignancy in Belfast, by P.C. Elmes, O.L. Wade (Annals of the New York Academy of Sciences, 1965).

The study

• Authors: P.C. Elmes, O.L. Wade
• Journal: Annals of the New York Academy of Sciences
• Published: 1965;132(1):549-57
• Cited by: 39 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001522).

Abstract

A study of 43 cases in Belfast has revealed a relationship between exposure to asbestos at work and the development of mesothelial tumor of the pleura.

Evidence has been produced which indicates that the exposure associated with this tumor need not be severe or prolonged, and that as many as a quarter of the male population of this area may have received sufficient exposure.

Among asbestos workers carcinoma of the lung is at least as frequent a cause of death as mesothelioma but the increasing widespread use of asbestos may be exposing a wide section of the population to the risk of secondary neoplasia.

PubMed has no abstract for this study. This is the authors' abstract, copied from the article.

In plain English

This interim report from Belfast, Northern Ireland, studied pleural mesothelioma and asbestos. By July 1964, 45 cases had been found, including 15 reported earlier. Three were excluded because enough clinical details could not be obtained. Patients' work histories and lung tissue were compared with matched controls of the same age and sex. About three-quarters of mesothelioma patients had a history of asbestos exposure, versus about a quarter of controls, a statistically significant difference. Most had intermittent or casual exposure, as in shipyard plumbers and boiler repairers, rather than full-time insulating work. Over three-quarters of the mesothelioma lungs examined contained asbestos bodies, versus a quarter of control lungs. In 200 autopsies on men without lung cancer, one in five had asbestos bodies. Among 30 insulation workers' deaths with reliable information, over half were from malignant disease. The authors said the meaning of this could not be judged without a control series. The authors concluded that exposure linked to this tumor need not be severe or prolonged, and that as many as a quarter of local men may have received sufficient exposure.

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: Interim report combining a case-control comparison of pleural mesothelioma patients with matched controls (occupational histories and lung asbestos bodies), autopsy surveys of asbestos bodies, a survey of causes of death among members of an insulation workers' union branch, and a study of Belfast as an environment
• Who was studied: 45 cases of pleural mesothelioma detected in Belfast up to July 1964, including 15 reported earlier by McCaughey. Three died before 1950 and were excluded from the rest of the investigation. Patients were diagnosed at ages 38 to 88 (mean 59 years), and only 2 were women. Matched controls of the same age and sex came from biopsy or autopsy registers. Further groups were: 20 autopsy patients with asbestos bodies and 20 matched controls; lungs from 200 autopsies on men aged 50 to 69 without malignant lung disease; lungs from 100 men dying of carcinoma of the bronchus, with matched controls for the most recent 50; and men who were members of a single Transport and General Workers Union branch of insulation workers in 1957.
• Exposure: Asbestos exposure, assessed by occupational history and by asbestos bodies in lung tissue. Fiber types were not specified. Occupational exposure was classed as 'Heavy' (full-time insulating work) or light (intermittent exposure, for example shipyard plumbers and boiler repairers). The insulation workers handled asbestos and other heat and fire insulation materials, including boiler composition, a powder of 85 per cent magnesia and 15 per cent asbestos fiber.
• Main results:
  • Significantly more patients in the mesothelioma group than in the matched control group had been exposed to asbestos. About three-quarters of mesothelioma patients had an exposure history, versus one in four controls.
  • Combining the light and heavy exposure groups, the difference between mesothelioma patients and controls was significant (P less than 0.001).
  • Among mesothelioma patients versus controls, the numbers employed full time on insulating work ('Heavy') were not enough to be statistically significant.
  • Most mesothelioma patients had a history of only intermittent or casual exposure, sometimes many years earlier. The majority were not directly employed in the insulating industry.
  • Over three-quarters of the mesothelioma lungs examined contained asbestos bodies, compared with only a quarter of matched control lungs. The authors described this difference as highly significant.
  • In a blind comparison, about three-quarters of the 20 autopsy patients with asbestos bodies had a positive history of exposure, compared with a quarter of the 20 matched patients without asbestos bodies.
  • Of the 200 autopsies on men without pulmonary malignancy, one in five had asbestos bodies in the lung.
  • Among these 200 autopsies, asbestos bodies were more frequent in men aged 60 to 69 than in men aged 50 to 59.
  • The 100 men with carcinoma of the bronchus showed about the same incidence of asbestos bodies as the control groups. The authors stated that their other statistics failed to show asbestos exposure was a significant cause of lung carcinoma in the Belfast population.
  • When the homes of mesothelioma patients without more than light industrial exposure were plotted on a map, there was no grouping to suggest an environmental cause.
  • Of 43 deaths recorded in the union branch in the last seven years, reliable information was available for 30 so far. Of those 30, 16 deaths were from malignant disease and 14 from nonmalignant disease.
  • The 30 insulation workers had a mean age at death of 55.3 years, with a range of 37 to 66 years.
  • The worker survey found three cases of peritoneal tumor. The authors judged these consistent with peritoneal mesothelioma, though complete autopsies were lacking for two of them.
  • Among the insulation workers' deaths there were two cases of classical fibrosis and cor pulmonale in men who started work before the dangers of asbestos were appreciated. One other man died of cor pulmonale after only 18 years in the industry.
• The authors' conclusion: The authors concluded that their data showed an association between asbestos exposure and pleural mesothelioma in Belfast. They concluded that the exposure needed to induce mesothelioma is much less than that of insulation workers and need not be severe or prolonged, and that as many as a quarter of the male population of the area may have received sufficient exposure. They also concluded that among asbestos workers, carcinoma of the lung is at least as frequent a cause of death as mesothelioma.
• Limitations the authors state:
  • The investigations were not complete; this was an interim report.
  • The methods for detecting past exposure and lung asbestos were not very efficient. About a quarter of patients were wrongly recorded as negative, which the authors said underestimated the correlation.
  • Without a proper control series, the significance of the high rate of malignant disease among insulation workers could not be determined.
  • The information on insulation workers' deaths was incomplete.
  • Complete autopsies were not available for two of the three peritoneal tumor cases, so a sure diagnosis could not be made.
  • Accurate information on the number of men employed in different industries over the past 50 years could not be obtained.
  • The investigation was not advanced enough to confirm a relationship between asbestos and other alimentary tumors.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Pleura, Carcinoma, Mesothelioma.

Related studies

• Insulation workers in Belfast. 3. Mortality 1940-66 — P.C. Elmes, M.J. Simpson (1971)
• Insulation workers in Belfast. A further study of mortality due to asbestos exposure (1940-75) — P.C. Elmes, M.J. Simpson (1977)
• Insulation workers in Belfast. 1. Comparison of a random sample with a control population — W.F. Wallace, J.H. Langlands (1971)
• Asbestos, mesothelioma and the legacy of shipbuilding in Belfast — P.J. Morrison (2008)
• Intraperitoneal chemotherapy for peritoneal surface malignancy: experience with 1,000 patients — E.A. Levine, J.H. Stewart, et al. (2014)
• What made hyperthermic intraperitoneal chemotherapy an effective curative treatment for peritoneal surface malignancy: A 25-year experience with 1,125 procedures — G. Passot, D. Vaudoyer, et al. (2016)

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