Secular changes in asbestosis in an asbestos factory

Our plain-English summary of Secular changes in asbestosis in an asbestos factory, by W.J. Smither (Annals of the New York Academy of Sciences, 1965).

The study

• Author: W.J. Smither
• Journal: Annals of the New York Academy of Sciences
• Published: 1965;132(1):166-81
• Cited by: 22 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. 002510).

Summary of the article

The author examined how asbestosis had changed over about 30 years in a single London East End factory that had made asbestos products since 1913. He compared earlier published series from this factory (Hunter, 1930-34; Wyers, 1949; Williams and Hugh-Jones, 1958-59; Thomson et al.) with 26 new cases certified since 1960. He also compared 71 post-mortem examinations since 1957, 51 attended by the writer, with Wyers' 115 post-mortem cases. Mean exposure before certification rose from 7 years (Hunter) to 10.4, then 14.5, and 17.5 years in the present series (range 4-35), although many present cases were found early through lung function testing. Breathlessness was reported by 69 per cent of new cases, against nearly all earlier cases. Mean DLCO was 19.3, against 13.9 in the Thomson series. Among deaths, mean age rose from 40.8 to 56.5 years and mean duration of disease from 6.4 to 7.25 years. Tuberculosis at death fell from 31.3 per cent to four cases, all with old healed lesions. Lung carcinoma rose from 14.8 to 36.6 per cent, and there were two pleural mesotheliomas or endotheliomas (2.8 per cent). Smoking habits were not recorded, so the author stated that the link between these cancers and asbestos could not be indicated. He concluded that better working conditions had lengthened exposure before certification despite earlier case finding.

PubMed has no abstract for this study, and the article doesn't print one. We wrote this summary from the full article with the help of AI. It is not the authors' wording.

In plain English

The author compared asbestosis cases from one asbestos products factory in London's East End over about 30 years. Twenty-six cases certified since 1960 were set against earlier published series drawn wholly or partly from this factory. Seventy-one post-mortems since 1957 (50 males, 21 females) were compared with Wyers' earlier series of 115. The factory processed chrysotile, crocidolite and amosite. Average exposure before certification was seven years for cases in the early 1930s and 17.5 years for the present cases. The author concluded that improved working conditions had lengthened this period despite earlier case finding. Only 69 per cent of the new cases complained of breathlessness. Mean age at death in the post-mortem series was 56.0 years for men and 57.7 for women, against 46.5 and 37.5 in Wyers' series. Tuberculosis at death fell from 36 cases (31.3 per cent) to four, all with only old healed lesions. Lung carcinoma rose from 14.8 to 36.6 per cent. Endothelioma of the pleura rose from one case (0.8 per cent) to two (2.8 per cent). Smoking was not recorded, so the link between these cancers and asbestos could not be gauged.

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: Descriptive comparison of a current series of certified asbestosis cases and post-mortem examinations from one factory with earlier published series, which were drawn wholly or partly from the same factory
• Who was studied: Workers from a single asbestos factory in the East End of London. The present study covered 26 new asbestosis cases certified since 1960 and 71 post-mortem examinations since 1957 (50 males and 21 females). These were compared with several earlier series. Hunter's series had 30 cases (1930-34), most of whom had worked at this factory. Wyers' series (1949) had 53 cases, 28 of them under his care at the factory, plus 115 post-mortems. The 1958-1959 series came from this factory.
• Exposure: Work in asbestos product manufacture. Chrysotile, crocidolite and amosite were all processed in the factory in amounts and proportions that varied over the years. Fiber type was not recorded for individual workers.
• Main results:
  • Cases certified in the early 1930s (Hunter's series) had an average exposure of seven years before certification.
  • The 26 cases certified since 1960 had an average exposure of 17.5 years before certification, ranging from four to 35 years.
  • 69 per cent of the new cases complained of breathlessness, although all met modern diagnostic criteria.
  • Mean age at death for males was 46.5 years in Wyers' series and 56.0 in the present post-mortem series.
  • Mean age at death for females was 37.5 years in Wyers' series and 57.7 in the present post-mortem series.
  • Tuberculosis at death fell from 36 cases (31.3 per cent) in Wyers' series to four cases in the present post-mortem series, all with only old healed lesions.
  • Carcinoma of the lung rose from 14.8 per cent of post-mortem cases in Wyers' series to 36.6 per cent in the present series.
  • Endothelioma of the pleura: Wyers reported one case (0.8 per cent). The present post-mortem series contained two cases (2.8 per cent).
  • In the present post-mortem series, mean age at death was four years higher in males with malignancy than in those without. This difference was not statistically significant.
  • The longest interval between exposure and development of asbestosis among the 71 post-mortems was 38 years.
  • Ten recently diagnosed men with asbestosis were matched with 10 men without the disease. Before diagnosis, eight of the cases had a total of 346 days of absence for nontuberculous respiratory illness. Six of the controls had a total of 180 days. The author called this evidence quite inconclusive.
• The authors' conclusion: The author concluded that improvement in working conditions had extended the exposure period before certification, in spite of earlier case finding.
• Limitations the authors state:
  • Smoking habits were not recorded, so the author could not indicate how far the malignancy in the series related to asbestos exposure.
  • Records of dust levels over the past 30 years were inadequate for comparison.
  • None of the earlier authors reported the type of asbestos fiber to which workers were exposed.
  • Records of the numbers employed were incomplete for the prewar period, so figures before 1942 were estimated.
  • Earlier series were certified on definite clinical and radiological findings. The present group included many picked up with minimal findings but impaired pulmonary function, so the series are not directly comparable.

Topics

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

Medical terms in this study, explained in our Lexicon: Autopsy, Diffusing Capacity (DLCO), Carcinoma, Pleural Mesothelioma, Habit.

Related studies

• Cohort analysis of changes in incidence of bronchial carcinoma in a textile asbestos factory — J.F. Knox, R.S. Doll, et al. (1965)
• Study of the secular trend in asbestos bodies in lungs in London 1936-66 — C.H. Um (1971)
• Mortality of factory workers in east London 1933-80 — M.L. Newhouse, G. Berry, et al. (1985)
• Combined effect of asbestos and smoking on mortality from lung cancer and mesothelioma in factory workers — G. Berry, M.L. Newhouse, et al. (1985)
• Mortality from all cancers of asbestos factory workers in east London 1933-80 — G. Berry, M.L. Newhouse, et al. (2000)
• Radiographic Changes in Colombian Asbestos Factory Workers — A.L. Frank, G. Villamizar, et al. (2020)

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