Asbestos-associated deaths among insulation workers in the United States and Canada, 1967-1987

Our plain-English summary of Asbestos-associated deaths among insulation workers in the United States and Canada, 1967-1987, by I.J. Selikoff, H. Seidman (Annals of the New York Academy of Sciences, 1991).

The study

• Authors: I.J. Selikoff, H. Seidman
• Journal: Annals of the New York Academy of Sciences
• Published: 1991;643:1-14
• Type of article: Review
• Cited by: 101 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Summary of the article

After reviewing the history of how asbestos disease was recognized, including among insulation workers, the authors reported 20 years of mortality follow-up of insulators. The cohort comprised 17,800 men enrolled in the insulators' union in the United States and Canada on January 1, 1967. They were followed from 1967 through 1986, giving 301,592.6 person-years of observation. Causes of death were taken from death certificates and were also assigned by "best evidence" after review of clinical, X-ray and pathology material. Mesothelioma was counted only when histopathology was verified by the authors' pathologist. Expected deaths were based on U.S. white male rates. There were 4,951 deaths against 3,453.5 expected. By best evidence there were 1,168 lung cancer deaths (268.66 expected), 173 pleural and 285 peritoneal mesotheliomas, 189 gastrointestinal cancer deaths (135.69 expected) and 427 asbestosis deaths. Cancers of the oropharynx and buccal cavity, larynx, kidney, pancreas (54 observed, 39.52 expected), and gallbladder and bile ducts were also increased. Apparent excesses of brain and liver cancer on death certificates disappeared after review, mainly because metastases had been misdiagnosed as primary tumours. No increase was found for cancer of the urinary bladder, prostate, testis, primary liver or brain, or for melanoma, leukemia or lymphoma. Little or no excess occurred within 15 years of onset of work, and most excess risk appeared 25 to 35 or more years after onset. The authors concluded that each organ appears to have its own neoplastic response to asbestos.

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

This study followed 17,800 men in the insulation workers' union in the United States and Canada from 1967 through 1986. Deaths were compared with numbers expected from U.S. white male death rates. Causes were counted from death certificates and also as "best evidence" after review of medical and pathology records. Mesothelioma was counted only when the authors' pathologist verified the tissue. In all, 4,951 men died, against 3,453.5 expected. By best evidence there were 1,168 lung cancer deaths (268.66 expected), 173 pleural and 285 peritoneal mesotheliomas, and 427 asbestosis deaths. Cancers of the oropharynx and buccal cavity, larynx, kidney, pancreas, and gallbladder and bile ducts were also increased. For pancreatic cancer there were 54 best-evidence deaths against 39.52 expected. Apparent excesses of brain and liver cancer on death certificates were not confirmed after review. The authors tentatively concluded there was no increase in bladder, prostate, testis, primary liver or brain cancer, leukemia or lymphoma. Little or no increase appeared within 15 years of starting work. Most excess risk came 25 or more years later.

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: Prospective cohort mortality study with 20 years of follow-up (1967-1986). Observed deaths were compared with deaths expected from U.S. white male death rates.
• Who was studied: 17,800 men enrolled in the insulators' union (International Association of Heat and Frost Insulators and Asbestos Workers) in the United States and Canada as of January 1, 1967, followed to December 31, 1986. The follow-up totalled 301,592.6 person-years.
• Exposure: Work as asbestos insulation workers. Time since onset of insulation work was taken from union records. The article does not name the fiber types or give measured doses for this cohort.
• Main results:
  • Over the 20 years, 4,951 men in the cohort died. The expected number, based on all U.S. white males, was 3,453.5.
  • Lung cancer: 268.66 deaths were expected. There were 1,008 by death certificate (SMR 375) and 1,168 by best evidence (SMR 435), both p less than 0.001. The authors note that the best-evidence SMR was calculated for information only.
  • Pleural mesothelioma: 89 deaths by death certificate and 173 by best evidence. No expected rates were available.
  • Peritoneal mesothelioma: 92 deaths by death certificate and 285 by best evidence. No expected rates were available.
  • Mesothelioma was counted only when tissue was verified at Mount Sinai. Cases not so verified were excluded, even if others had called them mesothelioma.
  • Asbestosis: 201 deaths by death certificate and 427 by best evidence. No expected rates were available.
  • Gastrointestinal cancer (stomach, esophagus, colon/rectum): 135.69 deaths were expected. There were 188 by death certificate and 189 by best evidence (SMR 139 for each, p less than 0.001).
  • Cancers of the oropharynx and buccal cavity, larynx, kidney, pancreas, and gallbladder and bile ducts were also increased in incidence.
  • Pancreatic cancer: 39.52 deaths were expected and 54 were found by best evidence. The authors described this as a statistically significant increase.
  • Brain neoplasms: death certificates listed 40, against 26.35 expected. By best evidence there were 33, including 27 malignant, and there was no statistically significant increase.
  • Liver cancer: death certificates listed 31, against 11.06 expected. After review, only 12 were primary liver cancer; the authors attributed the excess to metastases misdiagnosed as liver cancer.
  • The authors tentatively concluded there was no increased incidence of cancer of the urinary bladder, prostate, testes, primary liver cancer, primary brain neoplasms, leukemia or lymphoma.
  • Latency: little or no increase in cancer and asbestosis was seen in fewer than 15 years from onset of work. Most of the increased risk was found 25 to 35 or more years from onset.
• The authors' conclusion: The authors concluded that asbestos insulation work was associated with increased cancer at a variety of sites but not others. In their words, each organ and tissue apparently has its own neoplastic response to asbestos. They also concluded that the increases were strongly related to time since onset of work.
• Limitations the authors state:
  • The authors note it is always difficult to obtain enough data to support the absence of increased risk. They call the negative findings tentative and limited to this group, at this time, under these circumstances.
  • SMRs using best-evidence counts were calculated for information only. The expected deaths come from death certificate rates, and the two are not strictly comparable.
  • In about 10% of cases no clinical or histopathological material was available, so the death certificate served as best evidence.
  • The authors acknowledge that some death certificate diagnoses may be faulty.

Topics

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

Medical terms in this study, explained in our Lexicon: Insulator, Death Certificate, Pathology, Mesothelioma, Histopathology, Lung Cancer, Peritoneal Mesothelioma.

Related studies

• Mortality experience of insulation workers in the United States and Canada, 1943--1976 — I.J. Selikoff, E.C. Hammond, et al. (1979)
• Mortality of brain tumors among asbestos insulation workers in the United States and Canada — H. Seidman, I.J. Selikoff, et al. (1982)
• Decline in death rates among asbestos insulation workers 1967-1986 associated with diminution of work exposure to asbestos — H. Seidman, I.J. Selikoff (1990)
• The occurrence of asbestosis among insulation workers in the United States — I.J. Selikoff, J. Churg, et al. (1965)
• Neoplasia among insulation workers in the United States with special reference to intra-abdominal neoplasia — E.C. Hammond, I.J. Selikoff, et al. (1965)
• Influence of age at death on accuracy of death certificate disease diagnosis: findings in 475 consecutive deaths of mesothelioma among asbestos insulation workers and asbestos factory workers — I.J. Selikoff (1992)

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