Preliminary results from a cohort of workers exposed to wollastonite in a Finish limestone quarry

Our plain-English summary of Preliminary results from a cohort of workers exposed to wollastonite in a Finish limestone quarry, by M.S. Huuskonen, J. Järvisalo, H. Koskinen, et al (Scandinavian Journal of Work, Environment & Health, 1983).

The study

• Authors: M.S. Huuskonen, J. Järvisalo, H. Koskinen, J. Nickels, J. Räsänen, S. Asp
• Journal: Scandinavian Journal of Work, Environment & Health
• Published: 1983;9(2 Spec No):169-75
• Type of article: Case report
• Cited by: 8 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. 001749).

Abstract

Wollastonite metasilicate fibers are rather similar in form, length, and diameter, but mineralogically different, to amphibole asbestos fibers. We have studied immunologic findings from 46 men exposed to wollastonite at a limestone quarry for at least 10 years. These workers showed a higher prevalence of positive serum rheumatoid factors than blood donors did. This finding resembles the one detected among asbestos workers. The group of wollastonite workers with radiological signs of pulmonary fibrosis had activities of serum angiotensin-converting enzyme that were similar to those of wollastonite workers without fibrosis. A mortality study of 238 quarry workers with 5,769 person-years was, as expected, nonpositive. It was interesting that one woman with 20 years of exposure to wollastonite and with no other known exposure to fibers revealed a malignant retroperitoneal mesenchymal tumor 30 years after the initial exposure. This kind of very rare tumor is difficult to distinguish from mesothelioma. However, this is only one case, and it is impossible to draw any definite conclusions.

In plain English

This Finnish report studied wollastonite-exposed workers at a limestone quarry. The authors describe this mineral as similar in size and shape to amphibole asbestos fibers but mineralogically different. First, 46 men exposed for at least 10 years had blood tests. Positive rheumatoid factor was more common in these workers than in blood donors. By one method (enzyme immunoassay) it was positive in 30% of quarry workers and 19% of donors. Levels of angiotensin-converting enzyme did not differ significantly between workers with and without lung fibrosis. Second, deaths from 1923 to 1980 among 238 workers (192 men, 46 women) were compared with national rates. There were 79 deaths against 96 expected, with no significant deviation for cancers or other cause groups. Third, the authors described a woman who worked at the quarry from 1933 to 1949 and had a malignant retroperitoneal tumor in 1963. It was first diagnosed as a malignant mesenchymal tumor; a British mesothelioma panel later called it a poorly differentiated epithelial tumor but could not rule out mesothelioma. The authors said this was only one case, allowing no definite conclusions.

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: Cross-sectional study of blood tests (immunologic findings and serum angiotensin-converting enzyme) in a group of workers, plus a retrospective mortality study of a quarry cohort, plus a description of one tumor case
• Who was studied: 46 men (mean age 48.0 years, range 32 to 64) exposed to wollastonite for at least 10 years (average 21.5 years) in a Finnish limestone quarry, compared with an earlier random sample of 504 healthy blood donors. The mortality cohort was 238 workers (192 men and 46 women) on the payroll for at least one year, followed 1923 to 1980.
• Exposure: Wollastonite, a naturally occurring acicular or fibrous metasilicate, in a limestone quarry. Workers were grouped by job title into four exposure groups: drilling and blasting; loading, transport and crushing; sorting; and others.
• Main results:
  • The 46 wollastonite-exposed men had a higher prevalence of positive serum rheumatoid factors than the blood donors. No difference in rheumatoid factor was found between quarry workers with and without signs of lung fibrosis on chest radiographs.
  • Rheumatoid factor measured by enzyme immunoassay was positive in 30% of the quarry workers and 19% of the blood donors.
  • Antinuclear antibodies at a titer of 1/10 or higher were found in 9% of the wollastonite workers and 11.0% of the blood donors.
  • Mean serum angiotensin-converting enzyme activity was not significantly different between workers with and those without pulmonary fibrosis.
  • In the mortality cohort from 1923 to 1980 there were 79 deaths, at ages 42 through 93, against 96 expected from general Finnish mortality rates. Among males there were 67 deaths against 79 expected; among females, 12 against 17 expected.
  • Death certificates showed no significant deviations from expected numbers for malignancies, cardiovascular diseases, all natural causes, or all causes of death. With a 10-year latency period applied, no difference was found between observed and expected cancer deaths.
  • The cancers found were four bronchial cancers, two ventricular cancers, one cancer of the rectum, one cancer of the lower lip, one melanoma and one malignant retroperitoneal mesenchymal tumor.
  • One woman was a nonsmoker with no known dust exposure other than her quarry work. She did various quarry jobs between 1933 and 1949 and had a malignant retroperitoneal tumor first observed in 1963, at age 73. Light microscopy led to a diagnosis of malignant mesenchymal tumor. The British Mesothelioma Panel later concluded it was a poorly differentiated epithelial tumor but that mesothelioma could not be ruled out.
• The authors' conclusion: The authors concluded that their rheumatoid factor results suggest a finding similar to that seen in asbestos workers. They said that the tumor case was only one case and that it was impossible to draw any definite conclusions from it.
• Limitations the authors state:
  • Past exposure could not be determined in detail, particularly in the early years of operation. Hygienic measurements describe only present exposure and probably underestimate earlier exposure levels.
  • Reliable information on smoking habits could not be obtained because many of the workers had died long ago.

Topics

Medical terms in this study, explained in our Lexicon: Wollastonite, Amphibole Asbestos, Pulmonary Fibrosis, Fibrosis, Mesenchymal Tumor, Mesothelioma.

Related studies

• Wollastonite exposure and lung fibrosis — M.S. Huuskonen, A. Tossavainen, et al. (1983)
• Mortality among a cohort of US man-made mineral fiber workers: 1985 follow-up — G.M. Marsh, P.E. Enterline, et al. (1990)
• Relative effects of asbestos and wollastonite on alveolar macrophages — W.H. Pailes, D.J. Judy, et al. (1984)
• The biological reactivity of calcium silicate composites: in vivo studies — R.J. Richards, T.D. Tetley, et al. (1981)
• Biological reactivity of calcium silicate composites--in vitro studies — J. Hunt, F.D. Pooley, et al. (1981)
• Genotoxicity of dimethylnitrosamine in the presence of chrysotile asbestos UICC B and xonotlite — F. Denizeau, M. Marion, et al. (1985)

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