Review of the Epidemiology of Man-Made Mineral Fibres

Our plain-English summary of Review of the Epidemiology of Man-Made Mineral Fibres, by J.W. Hill (1980).

The study

• Author: J.W. Hill
• Published: BIOLOGICAL EFFECTS OF MINERAL FIBRES (J.C. WAGNER, EDITOR), LYON: IARC SCIENTIFIC PUBLICATIONS, VOLUME 30, PP. 979-983 (1980)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library. The article is still under copyright, so we describe it here rather than post it.

In plain English

This was a short review of research on the health of workers exposed to man-made mineral fibres (MMMF), written by the Group Medical Adviser of Pilkington Brothers Ltd. The author grouped the evidence into early case reports, cross-sectional studies and cohort studies. The author wrote that the cross-sectional studies had shown no evidence of disease attributable to MMMF. In a cohort of 1448 white male glass-fibre insulation wool workers (Bayliss et al., 1976), 376 deaths were observed versus 404.24 expected, and respiratory malignancy deaths numbered 16 versus 20.23 expected. Deaths from non-malignant respiratory disease, excluding influenza and pneumonia, were 19 versus 10.04 expected. This excess was reported as statistically significant, but the author questioned it. In a study of 3400 employees of a plant making mineral fibres from rock or slag (Ness et al., 1979), overall mortality was as expected, and the excesses found did not reach statistical significance. The author concluded that no case of mesothelioma had been reported and that evidence on bronchitis was open to doubt and needed further study. The author noted small numbers and missing smoking histories.

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: review of epidemiological studies (case reports, cross-sectional prevalence studies, cohort studies)
• Who was studied: Studies reviewed included 1448 white males with five or more years of employment in US glass-fibre insulation wool production between 1940 and 1949, followed to 1972 (Bayliss et al., 1976), and 3400 employees who worked between 1940 and 1948 at a plant making mineral fibres from rock or slag (Ness et al., 1979)
• Exposure: Man-made mineral fibres (glass-fibre insulation wool; mineral fibres from rock or slag). In the Bayliss study, the reported mean concentration was 0.08 respirable fibres/ml.
• Main results:
  • The author reported that cross-sectional prevalence studies (chest X-rays, lung function, bronchitis questionnaires) had shown no evidence of disease attributable to MMMF.
  • Bayliss et al. cohort (glass-fibre wool workers): 376 deaths observed versus 404.24 expected.
  • Bayliss et al. cohort: respiratory malignancy 16 observed versus 20.23 expected, with no excess risk found.
  • Bayliss et al. cohort: non-malignant respiratory disease, excluding influenza and pneumonia, 19 deaths observed versus 10.04 expected. This was reported as significant; the author argued the comparison may be biased.
  • Ness et al. (rock or slag mineral fibre plant): no departure from the expected level of overall mortality in 3400 employees.
  • Ness et al.: excesses in cancers of the digestive tract, lymphatic and haemopoietic malignancy, and non-malignant respiratory disease, none statistically significant.
• The authors' conclusion: The author concluded that cohort studies showed no clear evidence of an excess risk of bronchogenic carcinoma related to MMMF exposure, that no case of mesothelioma had been reported, and that evidence on a risk of bronchitis was open to doubt and required further study.
• Limitations the authors state:
  • Smoking history was not available in the Bayliss study.
  • The excesses in the Ness study were based on small numbers.
  • The subjects were town-dwellers but were compared with the total white male US population.
  • The author stated that further information is needed.

Topics

Medical terms in this study, explained in our Lexicon: Epidemiology, Statistical Significance, Mesothelioma.

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