Mortality and morbidity among the working population of anthophyllite asbestos miners in Finland

Our plain-English summary of Mortality and morbidity among the working population of anthophyllite asbestos miners in Finland, by L.O. Meurman, R. Kiviluoto, M. Hakama (British Journal of Industrial Medicine, 1974).

The study

• Authors: L.O. Meurman, R. Kiviluoto, M. Hakama
• Journal: British Journal of Industrial Medicine
• Published: 1974;31(2):105-12
• Cited by: 83 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 nos. 001283, 001310).

Abstract

Meurman, L. O., Kiviluoto, R., and Hakama, M. (1974).British Journal of Industrial Medicine,31, 105-112. Mortality and morbidity among the working population of anthophyllite asbestos miners in Finland. A study has been made in Finland of the effects of anthophyllite asbestos on mortality and morbidity of 1 092 asbestos workers first employed at two mines between 1936 and 1969; 95% of workers were traced, 248 of whom had died. A similar number of age-sex-matched controls was selected from a township 60 km from the mines. The causes of death included an excess due to lung cancer and asbestosis, but cancers of the digestive system occurred in equal frequency, and neither the cases nor controls had any confirmed mesotheliomas. Assuming a multiplicative effect of asbestos and smoking, the relative risk of lung cancer was 17 for an asbestos worker who smokes in terms of a non-exposed non-smoker. The corresponding figures were 12 for a smoker without asbestos exposure and 1·4 for an asbestos worker who did not smoke. More heavy smokers were found among the asbestos workers than among the controls. A threefold excess of dyspnoea and a twofold excess of cough were recorded for the asbestos workers compared with the controls after adjustment for smoking.

In plain English

This paper summarized a study of people who worked three months or more between 1936 and 1967 at two anthophyllite asbestos mines, Paakkila and Maljasalmi, in North Savo, Finland. Age- and sex-matched controls came from an agricultural municipality about 60 kilometres away. Of 1092 employees, 1041 were fully followed up; 248 had died before 1 July 1967. Causes of death came from death certificates, symptoms from mailed questionnaires. Lung cancer was the main cause of death for 21 deceased employees and 13 controls, a difference that was not statistically significant. Against national figures, there was a significant excess (8 observed, 2.4 expected) among workers exposed more than 10 years. Asbestosis caused 13 deaths. No mesothelioma was confirmed, though one was suspected. After smoking adjustment, cough was 2.2 times as common in 787 living employees who answered questionnaires as in controls, and 4.4 times as common in 110 miners and mill workers exposed 10 years or more. Dyspnoea at rest was about three times as common. The authors concluded it was too early to draw far-reaching conclusions about cancer and anthophyllite.

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 and morbidity study of mine employees compared with age- and sex-matched controls. Deaths came from death certificates, and symptoms from mailed questionnaires, with rates adjusted for smoking.
• Who was studied: 1092 people who had worked for three months or more between 1 January 1936 and 1 July 1967 at the Paakkila and Maljasalmi anthophyllite asbestos mines in North Savo province, Finland. 1041 had complete follow-up and 51 were lost to follow-up. Of those followed, 248 had died before 1 July 1967, 6 died between 1 July 1967 and 20 May 1969, and questionnaires were received from 787 living employees. Controls came from the electoral lists of an agricultural municipality about 60 kilometres west of the mines.
• Exposure: Anthophyllite asbestos at two mines. A high-risk sub-group of 110 living employees consisted of miners and mill workers with 10 years or more of exposure. The main group included workers in jobs that were not particularly dusty, such as office or forest workers.
• Main results:
  • Lung cancer was the principal cause of death for 21 of 248 deceased asbestos employees and for 13 controls. The authors stated this excess was not significant.
  • The 13 lung cancer deaths among controls closely matched the 12.6 expected from national mortality statistics.
  • A proportional mortality comparison with the national population of Finland showed a significant excess of lung cancer deaths among workers with more than 10 years' exposure to anthophyllite: 8 observed, 2.4 expected.
  • Among living employees, 66.7 percent were smokers, compared with 60.1 percent of controls.
  • The authors calculated relative risks of lung cancer against a non-smoker without asbestos exposure. They assumed that the smoking difference among the living also applied to the dead, and that the asbestos and smoking risks multiply. On that basis the relative risk was 1.4 for a non-smoking asbestos worker.
  • Under the same assumptions, the calculated relative risk of lung cancer was 12 for a smoker without asbestos exposure and 17 for an asbestos worker who smokes.
  • Asbestosis was the primary cause of death in 13 asbestos employees.
  • No case of mesothelioma could be established with certainty. One was suspected on the basis of chest X-ray and long exposure to asbestos dust.
  • Of the nine deceased employees who had worked 20 years or more, six had asbestosis at the time of death and five died of lung cancer.
  • There was no excess risk of cancer of the digestive organs or of other cancers.
  • Cough was twice as common in the whole group of living asbestos employees (787 questionnaire respondents) as among controls (relative risk 2.2), with prevalence rates adjusted for smoking.
  • Cough was more than four times as common in the heavily exposed sub-group of 110 miners and mill workers with 10 years or more of exposure as among controls (relative risk 4.4).
  • After adjusting for smoking, dyspnoea at rest showed a three-fold risk for asbestos workers compared with controls. The authors found no trend in dyspnoea with increasing exposure. They stated that the excess could be assumed to be due to asbestos and might indicate more or less advanced asbestosis.
  • Self-rated state of health showed no effect of asbestos exposure in either the main group or the heavily exposed sub-group.
• The authors' conclusion: The authors concluded it was still too early to draw far-reaching conclusions about the association of malignancy with anthophyllite asbestos exposure in Finland, and that the material should be re-examined in 5 to 10 years. They also stated that the effects of asbestos in this study likely appeared more modest than in most other studies, mainly because of the type of reference population and the relatively short duration of exposure.
• Limitations the authors state:
  • The number of deaths was rather small, especially among those who had worked 10 years or more: there were only 43 such deaths, of which 34 were miners or mill workers with heavy exposure.
  • Smoking habits of the deceased employees and their controls were not obtainable.
  • For 10 of the 32 deaths certified as pulmonary tuberculosis, the authors considered the evidence incomplete. Some of these may have been lung cancer, other cancers or mesothelioma.
  • Several employees had died of lung cancer after the study ended.
  • The main group of living employees included many people who could not be considered actual asbestos workers.
  • The authors judged self-rated health too subjective a method to give reliable results.
  • The type of reference population and the relatively short duration of exposure may have made the effects appear more modest.

Topics

Medical terms in this study, explained in our Lexicon: Anthophyllite, Lung Cancer, Mesothelioma, Relative Risk, Asbestos Exposure.

Related studies

• Incidence of cancer among anthophyllite asbestos miners in Finland — L.O. Meurman, E. Pukkala, et al. (1994)
• Combined effect of asbestos exposure and tobacco smoking on Finnish anthophyllite miners and millers — L.O. Meurman, R. Kiviluoto, et al. (1979)
• The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part II. Mortality — H.E. Amandus, R. Wheeler (1987)
• The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part III. Radiographic findings — H.E. Amandus, R. Althouse, et al. (1987)
• Four cases of mesothelioma among Finnish anthophyllite miners — A. Karjalainen, L.O. Meurman, et al. (1994)
• The morbidity and mortality of vermiculite miners and millers exposed to tremolite-actinolite: Part I. Exposure estimates — H.E. Amandus, R. Wheeler, et al. (1987)

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