A follow-up study of workers from an asbestos factory

Our plain-English summary of A follow-up study of workers from an asbestos factory, by P.C. Elwood, A.L. Cochrane, I.T. Benjamin, et al (British Journal of Industrial Medicine, 1964).

The study

• Authors: P.C. Elwood, A.L. Cochrane, I.T. Benjamin, D. Seys-Prosser
• Journal: British Journal of Industrial Medicine
• Published: 1964;21(4):304-7
• Cited by: 26 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001553).

Abstract

Associations between exposure to asbestos and carcinoma of the lung, diffuse mesothelioma of the pleura, and diffuse abdominal tumours have been demonstrated. Only by an epidemiological approach can the total risks of exposure to asbestos be estimated, and such a study is reported here. This suggests that white asbestos (chrysotile) may not be a serious hazard as far as mesothelioma or abdominal tumours are concerned, though there is some evidence of an excess in the number of deaths from carcinoma of the lung and bronchus.

In plain English

This was a follow-up study of everyone who had worked six months or longer between 1936 and 1962 at an asbestos factory near Cardiff that made asbestos sheeting and pipe lagging. The authors reported that only chrysotile had been used since 1935, though some crocidolite may have been used in 1932-35. Of 1,165 men and 268 women, 1,024 men and 237 women were traced, and 133 men and 11 women had died. One man had died of pleural mesothelioma. He entered the industry in 1932, and it was not known whether he had been exposed to crocidolite. No deaths from diffuse abdominal tumours were found. Eleven other people had died of lung or bronchus cancer. Among men alive 15 years after first exposure, 7 deaths from neoplasms of the lung, bronchus and pleura were observed, against 3.02 expected from south-east Wales rates. Deaths from all causes numbered 46, against 47.87 expected. The authors concluded that chrysotile may not be a serious mesothelioma hazard but saw some evidence of excess lung cancer deaths. They noted small numbers, unknown smoking habits, mostly short exposures and short follow-up.

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: Follow-up (mortality) study of a factory workforce, comparing observed deaths with those expected from regional death rates
• Who was studied: 1,165 men and 268 women who had worked at least six months, between 1936 and 1962, at an asbestos factory near Cardiff, Wales. Of these, 1,024 men (88%) and 237 women (88%) were traced. The detailed analysis was confined to men.
• Exposure: Work in a factory making asbestos sheeting for the building industry and pipe lagging. Since 1935 only chrysotile from southern Africa and Canada was used. Some crocidolite may have been used from 1932 to 1935 in making high-pressure pipes. Most workers were exposed for relatively short periods.
• Main results:
  • Of those traced, 133 men (13%) and 11 women (5%) had died. The cause of death was ascertained for 127 of these deaths.
  • No death from a diffuse abdominal neoplasm was found. One man died of mesothelioma of the pleura. He had entered the asbestos industry in 1932, worked as a beater attendant for four years, and then worked in the drawing office until 1953.
  • Apart from the man with mesothelioma, 11 workers had died from carcinoma of the lung or bronchus.
  • Among men alive 15 years after first exposure, 7 deaths from neoplasm of the lung, bronchus and pleura were observed, against 3.02 expected from death rates for all men in south-east Wales.
  • In the same group of men: 46 deaths from all causes were observed against 47.87 expected; 10 deaths from all neoplasms against 9.10 expected; and 21 deaths from diseases of the circulatory system against 17.54 expected. The authors described these as no important excess overall, but some evidence of excess for neoplasms and circulatory causes.
  • Of the 21 men who died of circulatory disease 15 or more years after first exposure, only five had been exposed for 10 years or more. Cor pulmonale appeared on only one death certificate.
• The authors' conclusion: The authors concluded that white asbestos (chrysotile) may not be a serious hazard for mesothelioma or abdominal tumours, though there was some evidence of an excess of deaths from carcinoma of the lung and bronchus.
• Limitations the authors state:
  • The number of lung cancer deaths was very small and the smoking habits of those who died were unknown, so the importance of the excess could not be assessed.
  • Most workers had been exposed for relatively short periods, which the authors considered relevant to the risk of lung cancer.
  • Most workers were followed up only a little more than 15 years after first exposure, so the total risks of death from mesothelioma and lung cancer may have been considerably underestimated.
  • It was not known whether the one man who died of mesothelioma had been exposed to crocidolite during 1932-35.
  • The 15-year cut-off after first exposure was chosen in a largely arbitrary way.
  • Relatively few women were exposed, so the detailed analysis was confined to men.

Topics

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

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

Related studies

• Further follow-up study of workers from an asbestos cement factory — H.F. Thomas, I.T. Benjamin, et al. (1982)
• Cohort analysis of changes in incidence of bronchial carcinoma in a textile asbestos factory — J.F. Knox, R.S. Doll, et al. (1965)
• Adverse health effects of asbestos: solving mysteries regarding asbestos carcinogenicity based on follow-up survey of a Chinese factory — E. Yano (2018)
• Neoplasia among insulation workers in the United States with special reference to intra-abdominal neoplasia — E.C. Hammond, I.J. Selikoff, et al. (1965)
• Deciduoid mesothelioma: a report of 5 cases and literature review — J. Shia, R.A. Erlandson, et al. (2002)
• An attempt to use the WHO typing in the histological classification of lung carcinomas — A. Reinilä, K. Dammert (1974)

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