Anthophyllite Mining And Milling As A Cause Of Asbestosis

Our plain-English summary of Anthophyllite Mining And Milling As A Cause Of Asbestosis, by K. Ahlman, T.J. Partanen, E. Rintala, et al (1973).

The study

• Authors: K. Ahlman, T.J. Partanen, E. Rintala, M. Wiikeri
• Published: Biological Effects Of Asbestos (J.C. Wagner, Editor), Lyon: Iarc Scientific Publications, Volume 8, Pp. 165-168 (1973)
• Type of article: Conference paper
• Our copy: from Johns-Manville's own medical library, J-M no. 002374. The article is still under copyright, so we describe it here rather than post it.

In plain English

This report described the authors' clinical and epidemiological experience with workers at Finland's only anthophyllite asbestos quarry and mill, at Paakkila. The cohort comprised 1249 people (1044 men and 205 women) who had worked there at least three months, followed from 1936 to 1972. Dust surveys from 1965 to 1971 found nearly all count concentrations above the threshold limit values. Earlier dust data were not available. There were 105 known cases of asbestosis (89 men, 16 women). In a 1967 examination of 140 current and retired workers, chest X-rays showed asbestosis in 37. Among workers exposed more than 25 years, 47 per cent had asbestosis, as had one-third of the 286 people exposed six years or more. A mortality study cited by the authors (Nurminen, 1972) counted 24 of 222 deaths with asbestosis as the underlying cause, and 31 observed versus 12 expected deaths from respiratory tuberculosis. The authors concluded that exposure at this quarry and mill causes asbestosis, with incidence appearing to correlate with exposure duration. They noted small numbers, missing early dust data and likely missed cases.

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: Descriptive clinical and epidemiological report on a cohort of mine and mill workers. It includes a 1967 cross-sectional medical examination and mortality and survival data from a separately cited study (Nurminen, 1972).
• Who was studied: 1249 people (1044 men, 205 women) registered as workers or employees for at least three months at the Paakkila anthophyllite mine and mill in Finland, followed 1936 to 1972. Of the 1676 people registered, 423 with under three months' exposure were excluded. The 1967 examination covered 140 workers: 116 employed and 24 retired.
• Exposure: Anthophyllite asbestos dust in mining and milling. In four surveys between 1965 and 1971, nearly all count concentrations exceeded threshold limit values. No dust data exist before 1965.
• Main results:
  • 105 known cases of asbestosis in the 1249-person study cohort: 89 men and 16 women.
  • In the 1967 sample of 140 workers, X-rays showed asbestosis in 37: 18 mild, 12 moderate and 7 marked.
  • In the 1967 sample, those with asbestosis complained of significantly more symptoms of bronchitis and shortness of breath. They also had lower vital capacity and forced vital capacity values than those without asbestosis.
  • Among the 87 workers without asbestosis in the 1967 sample, lung function did not differ significantly by duration of exposure.
  • Of cohort workers with more than 25 years' exposure, 47% had asbestosis.
  • Asbestosis was diagnosed in one-third of the 286 individuals employed six years or more.
  • Sixty-six per cent of all known asbestosis cases had over 11 years of exposure.
  • Mortality study of workers employed at least three months between 1936 and 1966 (Nurminen, 1972), using death certificates. Of 222 deaths, 24 had asbestosis as underlying cause, and 17 more had asbestosis listed alongside another underlying cause.
  • In the same mortality study, there were 31 observed deaths from respiratory tuberculosis as underlying cause, compared with 12 expected.
  • Among 56 asbestosis patients diagnosed 1937 to 1952 who filed insurance claims (Nurminen, 1972), the 5-, 10- and 15-year survival rates were 78.5, 71.3 and 55.4.
• The authors' conclusion: The authors concluded that exposure to anthophyllite asbestos dust at this quarry and mill causes asbestosis. They found its incidence seemed to correlate with exposure duration, and they attributed the common occurrence to high dust concentrations.
• Limitations the authors state:
  • Small numbers in the 1967 sub-groups meant statistical significance was infrequently reached.
  • No information on dust concentrations was available before 1965.
  • Exposure to other contributing factors was hard to measure.
  • Some asbestosis cases must have been missed over more than 30 years of follow-up.
  • The survival group was selected (insurance claimants diagnosed 20 to over 30 years ago) and may not reflect all registered cases today.
  • Non-occupational pleural plaques are common in the district, so pleural findings alone could not be evaluated as diagnostic.
  • The clinical aspects of anthophyllite asbestosis had not been studied sufficiently to draw conclusions, owing to the small long-employed group and cases spread over more than 30 years.

Topics

Medical terms in this study, explained in our Lexicon: Anthophyllite, Threshold Limit Value (TLV), Chest X-Ray.

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