Mortality of asbestos workers in England and Wales 1971-81

Our plain-English summary of Mortality of asbestos workers in England and Wales 1971-81, by J.T. Hodgson, R.D. Jones (British Journal of Industrial Medicine, 1986).

The study

• Authors: J.T. Hodgson, R.D. Jones
• Journal: British Journal of Industrial Medicine
• Published: 1986;43(3):158-64
• Cited by: 44 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. 000402).

Abstract

A national study of British asbestos workers is briefly described and the mortality experience of 31 150 male asbestos workers in England and Wales who had been medically examined at least once as part of that survey is presented. The survey population is divided into workers with occupational exposure to asbestos before the inception of the 1969 Asbestos Regulations and those who worked with asbestos only after 1969. Of the 1128 who had died, 897 had worked before 1969; 34 of the death certificates received for these men mentioned mesothelioma and for another nine asbestosis was reported in the absence of mesothelioma or lung cancer. A statistically significant excess of lung cancer (SMR 136) was found. For the post-1969 workers, one case of asbestosis and one case of mesothelioma were reported, but further investigation of these cases showed probable occupational exposure to asbestos many years before 1969. The time from first exposure for this section of the population is too short to exclude an excess of asbestos related disease. The most noticeable excess of asbestos related disease was seen among the insulation workers who had more than twice (SMR 256) the expected number of deaths from lung cancer, and for whom almost 10% of all death certificates mentioned mesothelioma. No excess of any alimentary tract cancer was found and the population showed a significant deficit of large bowel cancer mortality (SMR 54).

In plain English

This study reported deaths up to the end of 1981 among 31 150 men in England and Wales who had joined a national survey of asbestos workers set up alongside the 1969 Asbestos Regulations, and who had been medically examined and traced. Deaths were compared with those expected from national male death rates. Men who had worked with asbestos before 1969 had 157 lung cancer deaths against 121.0 expected (SMR 129.7), an excess that was statistically significant. Thirty-four of their death certificates mentioned mesothelioma, and 11 mentioned asbestosis without mesothelioma or lung cancer. Men exposed only after 1969 showed a small, non-significant increase in lung cancer. Their one asbestosis death and one mesothelioma death were in men whose work histories showed probable earlier shipyard exposure. Insulation workers had 43 lung cancer deaths, more than twice the number expected (SMR 256). The authors found no excess of cancer of the oesophagus, stomach, colon or rectum, and fewer colon cancer deaths than expected. The authors concluded that insulation workers bore a much heavier burden of asbestos related disease than other sectors. They added that it was too soon to see effects of exposure that began only after 1969.

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: Mortality analysis (standardised mortality ratios against England and Wales male death rates) of a national survey of asbestos workers. The survey population was a mix of workers already in post when recruitment began (cross-sectional) and workers who joined later (cohort).
• Who was studied: 31 150 traced and medically examined male asbestos workers in England and Wales, out of 33 079 men entered into the survey by the end of 1981. They were followed from first examination to death, emigration or 31 December 1981.
• Exposure: Employment in factories or workplaces covered by the 1969 Asbestos Regulations. Workers were split into those exposed before 1969 and those exposed only after 1969, and analysed by cumulative years of exposure and by industry sector (e.g. insulation, construction, textiles, cement). Exposure levels and fiber type were not analysed.
• Main results:
  • Both groups had fewer deaths than expected overall: 897 observed against 1011.8 expected (SMR 88.7) in the pre-1969 group, and 231 against 273.7 (SMR 84.4) in the post-1969 group. The authors attributed this mainly to fewer deaths from circulatory and respiratory disease, consistent with a 'healthy worker effect'.
  • Men exposed before 1969 had 157 lung cancer deaths against 121.0 expected (SMR 129.7, significant at the 1% level). Excluding the first 10 years after first exposure, they had 152 against 112.1 expected (SMR 135.6).
  • Men exposed only after 1969 had 29 lung cancer deaths against 26.9 expected (SMR 108.0), a small increase that was not statistically significant.
  • 34 of the death certificates of men in the pre-1969 group mentioned mesothelioma.
  • 11 of the 12 death certificates mentioning asbestosis without mesothelioma or lung cancer were in the pre-1969 group.
  • The one man in the post-1969 group with asbestosis on his death certificate had worked as a carpenter in dockyard towns since 1932. The authors judged that he had probably been exposed to asbestos during his long career as a shipyard carpenter.
  • The one man in the post-1969 group who died of mesothelioma had worked in ship repairing and fitting out from 1942 until 1959. He was considered to have probably been exposed for a substantial period before 1969.
  • Insulation workers were the only sector in which all measures of asbestos related disease reached statistical significance. Their 43 observed lung cancer deaths were compared with the expected number.
  • Insulation workers had more than twice the expected number of deaths from lung cancer (SMR 256).
  • Asbestosis or mesothelioma, or both, was recorded in every industry sector.
  • There was no excess of cancer at the four main alimentary tract sites examined (oesophagus, stomach, colon, rectum), either overall or with increasing exposure. Colon cancer deaths in the pre-1969 group were 6 against 16.7 expected (SMR 36.0), a deficit significant at the 1% level.
  • The authors estimated that differences in smoking habits would predict a lung cancer SMR of only about 105. They stated that the lung cancer excess in the pre-1969 group and among insulators could not be put down to smoking differences.
• The authors' conclusion: The authors concluded that asbestos insulation workers bore a much heavier burden of asbestos related disease than workers in other sectors. They also concluded that, at least in this population, asbestos exposure was not associated with an increase in alimentary tract cancer.
• Limitations the authors state:
  • The follow-up of men exposed only after 1969 was too short to expect to see any effect of their exposure, even if such an effect existed.
  • The only part of the population in which asbestos disease could sensibly be looked for was cross-sectional, made up of survivors with pre-1969 exposure. The picture may therefore be biased, and the effects of time since first exposure, duration and changing exposure levels could not be separated.
  • No analyses were made by exposure level or fiber type, because the available measurements and fiber information covered only the period since the survey began.
  • The cross-sectional nature of the population would tend to raise the number of mesotheliomas recorded relative to lung cancers, by an amount that could not be quantified.
  • Mentions of asbestosis on death certificates were hard to interpret because the term was sometimes used loosely.
  • The estimate of 1961 smoking prevalence was based on information recalled later and may be subject to recall bias.

Topics

Medical terms in this study, explained in our Lexicon: Occupational Exposure, Death Certificate, Mesothelioma, Lung Cancer, Insulator.

Related studies

• Mortality from mesothelioma of the pleura during 1968-78 in England and Wales — M.J. Gardner, E.D. Acheson, et al. (1982)
• Work-related mortality in England and Wales, 1979-2000 — D. Coggon, E.C. Harris, et al. (2010)
• Trends in mortality from occupational hazards among men in England and Wales during 1979-2010 — E.C. Harris, K.T. Palmer, et al. (2016)
• Mesothelioma of the peritoneum during 1967-82 in England and Wales — M.J. Gardner, R.D. Jones, et al. (1985)
• Women's occupation and cancer: preliminary analysis of cancer registrations in England and Wales, 1971-1990 — J. Simpson, E. Roman, et al. (1999)
• Cancer in electrical workers: an analysis of cancer registrations in England, 1981-87 — N.T. Fear, E. Roman, et al. (1996)

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