The epidermiologic relationship between pleural mesothelioma and asbestos exposure

Our plain-English summary of The epidermiologic relationship between pleural mesothelioma and asbestos exposure, by M. Nurminen (Scandinavian Journal of Work, Environment & Health, 1975).

The study

• Author: M. Nurminen
• Journal: Scandinavian Journal of Work, Environment & Health
• Published: 1975;1(2):128-37
• Cited by: 23 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. 002330).

Abstract

This paper describes an investigation of 85 notifications of either probable or possible mesothelioma to the Finnish Cancer Registry from 1953 through 1969. The investigation covers characteristic epidemiologic features and the possibility of the mesothelioma being connected with occupational or other exposure to asbestos. The incidence rate of pleural mesothelioma was estimated at 1.1 per million per year. The male/female ratio was 1.3:1, which greatly differed fsrom that for malignant neoplasms of the bronchus or lung in Finland in 1960. The mean age at dealth from mesothelioma was over 7 years lower than that for bronchial carcinoma. The ratio of the crude incidence rates for the urban and rural populations was 4.2; the corresponding ratio for cases of carcinoma oopulations was 4.2; the corresponding ratio for cases of carcinoma of the bronchus or lung was 1.2 in Finland in 1960. THE LAST OCCUPATIONS OF THE 82 DECEASED PERSONS, OBTAINED FROM THE DEATH CERTIFICATES, WERE DIVIDIED INTO THREE CATEGORIES ACCORDING TO POSSIBLE ASBESTOS EXPOSURE. Exposure was present or probable in 9 (11.0) cases, 28 (34.2 %) had a possible exposure, and in 33 (40.2 %) cases exposure was absent or unlikely. The occupation of 12 (14.6) persons was unknown. Additional information of possible exposure history was obtained by interviewing the relatives of 10 mesothelioma patients. For half of the persons a definite, although in some cases trivial, exposure to asbestos could be ascertained. For the other five persons no exposure, either occupational, neighborhood or domestic, to asbestos could be traced. The residental distribution of the 85 persons with mesothelioma revealed no clustering of cases.

In plain English

This article partly reviewed earlier research on pleural mesothelioma and asbestos and partly reported a national study in Finland. The author examined 85 cases of probable or possible pleural mesothelioma notified to the Finnish Cancer Registry from 1953 through 1969. Peritoneal mesothelioma was not included. The estimated incidence was 1.1 per million per year, and the number of notified cases rose over the period. The male-to-female ratio was 1.3:1. The ratio of urban to rural incidence rates was 4.2. Of all patients, 74% died within a year of symptom onset. Based on the last occupation on the death certificates of 82 deceased persons, asbestos exposure was judged present or probable in 9 (11.0%), possible in 28 (34.2%), absent or unlikely in 33 (40.2%), and unknown in 12 (14.6%). Relatives of 10 patients were interviewed. Five of these patients had a definite, though sometimes trivial, asbestos exposure, and for the other five no exposure could be traced. Cases showed no residential clustering. The author concluded that some association between asbestos and mesothelioma seemed likely but was not proven. The author noted that death-certificate occupations were often recorded too vaguely.

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: Partly a review of earlier studies, and partly a national case series (case-history study) of pleural mesothelioma cases taken from the Finnish Cancer Registry, with death certificates and interviews of relatives
• Who was studied: 85 persons with pleural mesothelioma (51 probable, 34 possible) notified to the Finnish Cancer Registry, Finland, 1953 through 1969. Death certificates were available for 81 persons, and occupations were analysed for 82 deceased persons. Relatives of a random sample of 10 patients were interviewed. Peritoneal mesotheliomas were excluded.
• Exposure: Possible occupational, neighborhood or domestic asbestos exposure. It was judged from the last occupation on death certificates (present or probable, possible, absent or unlikely) and, for 10 patients, from relatives' accounts of lifetime work and home history. Fiber types were not determined for the cases.
• Main results:
  • The annual incidence of pleural mesothelioma in Finland was estimated at 1.1 per million.
  • Notified cases increased over the period: cumulative totals were 9 up to 1957, 33 up to 1963, and 85 up to 1969.
  • The male-to-female ratio among the mesothelioma cases was 1.3:1, compared with about 12:1 for bronchus and lung cancer in Finland in 1960.
  • Age at death of the 82 persons ranged from 3 to 93 years. The median age at death was in the 55 to 59 year interval.
  • Mean age at death from mesothelioma was over 7 years lower than for bronchial carcinoma.
  • Mean survival from diagnosis was approximately 5 months. Of all patients, 74% died within a year of symptom onset, and only three survived more than 2 years.
  • The ratio of crude incidence rates for urban versus rural populations was 4.2 for pleural mesothelioma, compared with 1.2 for bronchus and lung cancer in 1960.
  • Among the 82 deceased persons, last occupation indicated asbestos exposure present or probable in 9 (11.0%), possible in 28 (34.2%), and absent or unlikely in 33 (40.2%). Occupation was unknown for 12 (14.6%).
  • Of the 10 patients whose relatives were interviewed, five had a definite, although in some cases trivial, asbestos exposure. For the other five, no occupational, neighborhood or domestic exposure could be traced.
  • Among the interviewed cases, there was no systematic pattern in smoking habits suggesting that cigarette smoking was an important factor.
  • The residential distribution of the 85 cases matched Finland's population density and showed no clustering.
  • No mesotheliomas were reported from the communes surrounding the anthophyllite asbestos mine at Paakkila.
  • Only one person in the series had asbestosis.
• The authors' conclusion: The author concluded that some association between asbestos and mesothelioma seemed likely, but that probability alone was not enough to prove it. The author called for deeper evaluation of the hypotheses. The author also raised the possibility that pleural mesothelioma might be caused by some unsuspected environmental agent.
• Limitations the authors state:
  • Occupations on death certificates were often too general or uninformative. The author said this may partly explain why only 11% of occupations could be linked to asbestos.
  • The rising number of notified cases could reflect wider use of the diagnosis. Pleural mesothelioma is difficult to diagnose and may be misclassified in either direction.
  • No systematic data were available on asbestos fibers or bodies in sputum, lungs or tumor tissue.
  • Relatives were hard to locate, so only 10 interviews could be completed.
  • Massive migration in Finland in recent decades limits what the absence of residential clustering can show.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Mesothelioma, Asbestos Exposure, Mesothelioma, Cancer Registry, Incidence, Neoplasm, Bronchus, Carcinoma.

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• Quantitative relationships of exposure to chrysotile asbestos and mesothelioma mortality — D. Loomis, D.B. Richardson, et al. (2019)

Browse more research in Scandinavian Journal of Work, Environment & Health, or return to medical research.