Health hazards of asbestos exposure

Our plain-English summary of Health hazards of asbestos exposure (Annals of the New York Academy of Sciences, 1979).

The study

• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:1-814
• Cited by: 16 articles, as counted by NIH iCite
• Read it: PubMed

In plain English

This conference paper followed asbestos insulation union members in the United States and Canada. It analyzed 12,051 men who reached 20 or more years since entering the trade: 77,391 man-years and 1,946 deaths, 1967 to 1976. Expected deaths were based on 73,763 men from an American Cancer Society study, accounting for smoking, and on U.S. white males. All-cause mortality ratios were 1.70 against the control group and 1.41 against U.S. white males. Lung cancer mortality ratios ranged from 4.24 to 5.51. By best available evidence, 61 men died of pleural mesothelioma, 109 of peritoneal mesothelioma and 160 of asbestosis. Against men with neither asbestos exposure nor a cigarette smoking history, age-standardized lung cancer death rates were 5.17 times as high in asbestos workers who never smoked regularly and 10.85 times as high in men without asbestos exposure who had a cigarette smoking history. The authors concluded that asbestos dust and cigarette smoking had a strong synergistic effect on lung cancer, and that smoking increased the risk of asbestosis death. They stressed only one group of asbestos workers was studied.

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: Cohort study of union members who answered a 1966 questionnaire and were traced for deaths through 1976. Death certificates were checked against further medical evidence. Observed deaths were compared with expected deaths from a control group and from U.S. white males.
• Who was studied: 17,800 members of the asbestos insulation workers' union in the United States and Canada were alive on January 1, 1967. The report was limited to the 12,051 men who reached 20 or more years from onset of asbestos exposure during the study period. These men contributed 77,391 man-years and 1,946 deaths. The control group was 73,763 white, non-farmer men with no more than a high school education and a history of occupational exposure to dust, fumes, vapors, gases, chemicals or radiation.
• Exposure: Occupational exposure to asbestos dust in insulation work; fiber types were not specified. Cigarette, pipe and cigar smoking were also studied, as reported on the 1966 questionnaire.
• Main results:
  • Deaths from all causes among the asbestos workers had a mortality ratio of 1.70 compared with the control group and 1.41 compared with U.S. white males.
  • Lung cancer mortality ratios among the asbestos workers ranged from 4.24 (U.S. white males, death certificate causes) to 5.51 (control group, best evidence causes).
  • By the best available evidence, 61 asbestos workers died of pleural mesothelioma and 109 of peritoneal mesothelioma.
  • Asbestosis was the underlying cause of death for 76 men according to death certificates, and for 160 according to the best available evidence.
  • 46 deaths were attributed to pancreatic cancer on death certificates. Of these, 15 were found to be due to peritoneal mesothelioma.
  • Age-standardized lung cancer death rates (Table 8, death certificate causes) were compared with men who had neither asbestos exposure nor a history of cigarette smoking (ratio 1.00). 'No' smoking history meant never smoked regularly, and pipe or cigar only smokers were excluded. The ratio was 5.17 for asbestos workers who never smoked regularly and 10.85 for men without asbestos exposure who had a history of cigarette smoking.
  • Asbestos workers with a cigarette smoking history had a lung cancer death rate of 601.6 per 100,000 man-years. If the two exposures had acted independently, the expected rate would have been 169.7. The authors attributed the difference of 431.9 per 100,000 man-years to a synergistic effect.
  • Lung cancer deaths among asbestos workers with known smoking habits were compared with lung cancer death rates of control group men who never smoked regularly. This gave a mortality ratio of 46.23 overall, 87.36 for current smokers of 20 or more cigarettes a day, and 5.33 for asbestos workers who never smoked regularly.
  • Among asbestos workers who never smoked regularly, there were 5 asbestosis deaths against 13.3 expected (ratio .38). The asbestosis death rate of current smokers of 20 or more cigarettes a day was 2.8 times that of men who never smoked regularly.
  • For esophageal cancer, mortality ratios ranged from 2.64 to 3.34, and the mortality differences were statistically significant.
  • For stomach cancer, the mortality differences were not statistically significant.
  • The authors judged that pancreatic cancer death rates may be slightly elevated in asbestos workers, but that this was far from certain.
• The authors' conclusion: The authors concluded that the study indicates a strong synergistic effect between asbestos dust exposure and cigarette smoking on the risk of lung cancer. They also concluded that cigarette smoking increases the risk of death from asbestosis.
• Limitations the authors state:
  • Only one group of asbestos workers, members of the insulation workers union, was studied. The authors would not expect the exact figures to be duplicated in other groups of asbestos workers.
  • Control group death rates were known only to September 30, 1972, so they were extrapolated to cover the rest of the study period.
  • Causes of death on death certificates are not always accurate.
  • For the control group, additional cause-of-death information could not be obtained for deaths after 1965.
  • Mesothelioma death rates were not available for either comparison group, so expected numbers could only be presumed to be very low.
  • Small numbers limited some estimates. These included the lung cancer ratio for non-smoking asbestos workers and the identification of which other cancer sites are involved.

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestos Exposure.

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