Short-term asbestos work exposure and long-term observation

Our plain-English summary of Short-term asbestos work exposure and long-term observation, by H. Seidman, I.J. Selikoff, E.C. Hammond (Annals of the New York Academy of Sciences, 1979).

The study

• Authors: H. Seidman, I.J. Selikoff, E.C. Hammond
• Journal: Annals of the New York Academy of Sciences
• Published: 1979;330:61-89
• Cited by: 92 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 001051).

Summary of the article

The authors examined how the duration of work exposure to amosite asbestos related to later mortality, extending earlier follow-up of a factory cohort to 35 years. Between June 1941 and December 1945, 933 men were recruited to an amosite asbestos insulation factory in Paterson, New Jersey, that supplied the U.S. Navy. Many worked only briefly. After exclusions, 820 men were studied. Twenty were excluded for prior asbestos work, and 93 because they took asbestos work elsewhere, died, or were lost to follow-up within 5 years. Using generation life table methods, the authors compared observed cumulative probabilities of death from 5 through 35 years after onset of work, through 1977, with those expected from New Jersey white male rates, by length of time worked. Causes were coded from death certificates and from 'best evidence'; additional information was obtained for 413 (78%) of 528 deaths. Men who worked under one month had favorable all-cause mortality. In the other groups excess mortality appeared later, and was smaller, the shorter the work. There were 30 asbestosis deaths and 7 each of pleural and peritoneal mesothelioma. Among men aged 40-59 who had worked 9 months or more, lung cancer was about 10 times expected within 5-14 years. The authors concluded that lower dosage lengthened latency and reduced excess mortality, and that latency also depended on age at exposure.

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 men who began work at an amosite asbestos factory in Paterson, New Jersey, between 1941 and 1945. Many of them worked there only briefly. Of 933 men recruited, 820 were studied from 5 to 35 years after they started work, through 1977. The authors compared deaths in these men with deaths expected from the death rates of New Jersey white males, grouping the men by how long they had worked. There were 528 deaths. The 61 men who worked less than a month had lower than expected deaths from all causes throughout. In the other groups, excess deaths appeared later and less often the shorter the work. For lung cancer, observed probabilities of death were 2.94 times expected in the under-one-month group and 6.50 times expected in the two-years-or-more group. Among men in their forties and fifties who worked 9 months or more, large excesses appeared within 5 to 14 years. The authors concluded that lower dosage delayed adverse mortality and made it smaller. They noted that the factory had no dust measurements and that some subgroup figures were sparse.

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: Retrospective cohort mortality study. The authors used life-table methods to compare observed and expected cumulative probabilities of death. Expected values came from death rates for New Jersey white males. Men were grouped by length of time worked.
• Who was studied: 933 men recruited June 1941 through December 1945 to an amosite asbestos factory in Paterson, New Jersey, that supplied the U.S. Navy. 113 were excluded: 20 had prior asbestos work, 14 took up asbestos work elsewhere within 5 years, 41 died within 5 years, and 38 were lost to follow-up. That left 820 men, followed from 5 through 35 years after onset of work, up to December 31, 1977. The group was almost entirely white and older than usual for new workers. Mean age at the 5-year point was 41.9.
• Exposure: Work exposure to amosite asbestos in insulation manufacture, measured by length of time worked. Of the 820 men, 61 worked less than a month, 90 one month, 82 two months, 149 three to five months, 125 six to eleven months, 125 one year and 188 two years or more. There were no dust counts at this factory. In another plant of the same company making the same product with the same fibers, fiber counts in samples taken in October 1971 averaged as high as 23 fibers/ml.
• Main results:
  • All 820 men: 528 died between 5 and 35 years after onset of work. Their cumulative probability of death from all causes was 66.09%, against 49.72% expected.
  • The 61 men who worked less than a month had favorable (lower than expected) all-cause mortality for the entire observation period.
  • In the other length-of-work groups, unfavorable mortality became evident later, and with lesser frequency, the shorter the work exposure.
  • Men who worked two years or more (188 men): 157 died. Their cumulative probability of death over 5 to 35 years was 85.19%, against 59.06% expected. The authors described them as close to extinction at 35 years.
  • Using best available evidence, 30 deaths were assigned to asbestosis, 7 to pleural mesothelioma and 7 to peritoneal mesothelioma. Of these 44 deaths, only 1 was among men who had worked less than 6 months (out of 215 deaths in that group). Thirty-one were among the 157 deaths in men who had worked two years or more.
  • Lung cancer (best-evidence coding), men who worked less than one month: over 5 to 35 years, the ratio of observed to expected cumulative probability of death was 2.94. This figure rests on small numbers.
  • Lung cancer (best-evidence coding), men who worked two years or more: over 5 to 35 years, the ratio of observed to expected cumulative probability of death was 6.50.
  • The authors grouped several conditions as all 'asbestos' diseases: asbestosis and other noninfectious lung disease, lung cancer, mesothelioma, and cancers of the esophagus, stomach, colon-rectum, larynx, mouth, pharynx and kidney. This category did not account for all of the excess deaths among the workers.
  • Men in their forties and fifties who worked 9 months or more, 5 to 14 years after onset: the probability of death was almost double the expected for all causes. It was 6 times expected for all 'asbestos' diseases, 4 times expected for total cancer and about 10 times expected for lung cancer.
  • Men in their forties and fifties who worked less than 9 months: little or no excess mortality appeared before the 15-year point after onset. After that, observed probabilities of death for all 'asbestos' diseases, all cancer and lung cancer were about two or three times expected.
  • Men in their twenties at the 5-year point had few deaths in the following ten years, regardless of exposure level.
• The authors' conclusion: The authors concluded that, using length of time worked as a measure of dose, in general the lower the dosage, the longer adverse mortality took to appear and the smaller it was. They stated that asbestos retained in the tissues ('residence' exposure) continues after direct exposure stops, and that lighter exposure requires prolonged follow-up. They also concluded that the length of the latency period depends on both dosage and age at exposure.
• Limitations the authors state:
  • There were no direct dust measurements at this factory. Exposure was inferred from length of time worked and from counts taken at another plant of the same company.
  • The authors questioned whether the general population was a suitable comparison. They noted that New Jersey cancer rates are among the highest in the United States.
  • Results for small groups are subject to substantial sampling variability. Some subgroup figures are very sparse.
  • The data are subject to selective mortality, interaction with cigarette smoking, and competing causes of death. Unknown confounding factors may also be present.
  • General-population death data for 1977 were not available and were extrapolated from 1970 to 1976.

Topics

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

Medical terms in this study, explained in our Lexicon: Amosite, Death Certificate, Peritoneal Mesothelioma, Lung Cancer, Latency.

Related studies

• Mortality experience of amosite asbestos factory workers: dose-response relationships 5 to 40 years after onset of short-term work exposure — H. Seidman, I.J. Selikoff, et al. (1986)
• Mesothelioma continues to increase even 40 years after exposure - Evidence from long-term epidemiological observation — B. Świątkowska, N. Szeszenia-Dąbrowska (2017)
• Further observations on the short-term retention and clearance of asbestos by rats, using UICC reference samples — A.P. Middleton, S.T. Beckett, et al. (1979)
• Long term radiological effects of short term exposure to amosite asbestos among factory workers — R. Ehrlich, R. Lilis, et al. (1992)
• Long-term mortality experience of chrysotile miners and millers in Thetford Mines, Quebec — W.J. Nicholson, I.J. Selikoff, et al. (1979)
• Different Cellular Response of Human Mesothelial Cell MeT-5A to Short-Term and Long-Term Multiwalled Carbon Nanotubes Exposure — L. Ju, W. Wu, et al. (2017)

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