Predictions of mortality from mesothelial tumours in asbestos factory workers

Our plain-English summary of Predictions of mortality from mesothelial tumours in asbestos factory workers, by M.L. Newhouse, G. Berry (British Journal of Industrial Medicine, 1976).

The study

• Authors: M.L. Newhouse, G. Berry
• Journal: British Journal of Industrial Medicine
• Published: 1976;33(3):147-51
• Cited by: 84 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. 002304).

Abstract

Using the accumulated data on deaths from mesothelial tumours among cohorts of male and female factory workers at a London asbestos textile factory, the mortality from this cause up to the year 2000 AD has been predicted. The limitations of the methods used are pointed out, but it is estimated that for men the mortality due to mesothelial tumours will be between 7% and 11% of the total mortality and somewhat higher for women. The highest number of deaths from mesothelial tumours will occur during the 1980s, thereafter the numbers will decline because of the decreasing size of the cohort resulting from general mortality.

In plain English

The authors followed deaths among past workers at an east London asbestos factory that made textiles and heat insulating materials, using chrysotile, amosite and crocidolite, with mixed exposures the rule. The groups were about 3000 men first employed from 1933 to 1964, excluding laggers, and about 700 women first employed from 1936 to 1942. Up to 30 September 1972, among men who survived at least 10 years after first employment, 31 of 426 deaths (7.3%) were from mesothelial tumours. Among women the figure was 14 of 158 (8.9%). Of these 45 tumours, 23 were pleural and 22 peritoneal. The tumour death rate rose with time since first exposure, and it was higher with more severe and longer exposure. Using a mathematical model, the authors projected 121 to 194 tumour deaths in men and 42 to 59 in women over 1971 to 2000, with the peak in the 1980s. They predicted that by 2000 these tumours would account for 7.3% to 10.8% of deaths in men and 9.1% to 12.0% in women. The authors called such projection hazardous. They cited imprecise estimates from limited data and possible changes in dust levels and death rates.

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 follow-up of two factory worker cohorts, with mathematical projection of future mesothelioma deaths up to the year 2000
• Who was studied: About 3000 men first employed from 1933 to 1964 (laggers excluded) and about 700 women first employed from 1936 to 1942 at an asbestos factory in the east end of London, followed to 30 September 1972
• Exposure: Work making asbestos textiles and asbestos heat insulating materials. Chrysotile, amosite and crocidolite were all used, and mixed exposures were the rule. Workers were grouped as severe or low-moderate exposure, and as employed less than two years or two years or more.
• Main results:
  • Men who survived at least 10 years after first employment: 31 of 426 deaths up to 30 September 1972 were from a mesothelial tumour (7.3%)
  • Women: 14 of 158 deaths were from a mesothelial tumour (8.9%)
  • Of the 45 mesothelial tumours in both groups, 23 were pleural and 22 peritoneal
  • The mesothelioma death rate per 100 000 subject years rose from 6 at 10 to 15 years after first exposure to 318 at 30 or more years
  • Those with low-moderate exposure and short employment had a mesothelioma rate about one-sixth of that of those with severe and long exposure. These rates were not adjusted for differences in follow-up.
  • Men: predicted 121 to 194 mesothelial tumours for 1971 to 2000. By 2000 AD, these tumours were predicted to make up between 7.3% and 10.8% of deaths.
  • Women: predicted 42 to 59 mesothelial tumours for 1971 to 2000. By 2000 AD, these tumours were predicted to make up between 9.1% and 12.0% of deaths.
  • Even with the lowest estimates, the peak was predicted for the 1980s. Incidence at the turn of the century was predicted to be similar to the level at the time of writing.
  • For men, the alternative model estimate (k = 2) raised projected tumours by about 35%. Assuming half the risk for men first employed after 1950 lowered them by about 15%.
• The authors' conclusion: The authors concluded that the conditions responsible were not those that should be achieved today. They stated that the dose response evidence shows improved control of factory environments should markedly reduce risks.
• Limitations the authors state:
  • The authors described projecting 30 years ahead, based on 45 tumours observed over 20 years, as a hazardous process
  • The model's parameter estimates were imprecise because of limited data
  • National death rates will probably change over the next 30 years
  • The dust hazard in the factory may have changed during the period of exposure
  • The rates by severity and length of exposure (Table 3) were not adjusted for differences in length of follow-up between groups

Topics

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

Related studies

• Mortality of factory workers in east London 1933-80 — M.L. Newhouse, G. Berry, et al. (1985)
• Combined effect of asbestos exposure and smoking on mortality from lung cancer in factory workers — G. Berry, M.L. Newhouse, et al. (1972)
• Mortality from all cancers of asbestos factory workers in east London 1933-80 — G. Berry, M.L. Newhouse, et al. (2000)
• Combined effect of asbestos and smoking on mortality from lung cancer and mesothelioma in factory workers — G. Berry, M.L. Newhouse, et al. (1985)
• A study of the mortality of workers in an asbestos factory — M.L. Newhouse (1969)
• A study of the mortality of female asbestos workers — M.L. Newhouse, G. Berry, et al. (1972)

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