Mortality Experiences Among Talc Workers: A Follow-Up Study

Our plain-English summary of Mortality Experiences Among Talc Workers: A Follow-Up Study, by M. Kleinfeld, J. Messite, M.H. Zaki (1974).

The study

• Authors: M. Kleinfeld, J. Messite, M.H. Zaki
• Published: Journal Of Occupational Medicine 16(5):345-349, May (1974)
• Type of article: Journal article
• Our copy: from Johns-Manville's own medical library, J-M no. 002356. The article is still under copyright, so we describe it here rather than post it.

In plain English

The authors followed 260 talc workers with 15 or more years of exposure to commercial talc dust, recording deaths from 1940 to 1969. This updated an earlier study. The dust was mainly talc, tremolite, anthophyllite and carbonate dusts. For lung and pleural cancer, gastrointestinal and peritoneal cancer, and cardiac disease, the authors compared observed shares of deaths with those expected among United States white men. Of 108 deaths, 13 were lung and pleural cancers (12 lung carcinomas, 1 pleural fibrosarcoma). These made up about four times the expected share of deaths, with a significant increase at ages 60 to 79 rather than 40 to 59. The excess was significant in 1950-54, not in 1960-64 or 1965-69. Gastrointestinal and peritoneal cancers (9, including 1 peritoneal mesothelioma) did not differ significantly from expected. Twenty-nine deaths were from pneumoconiosis and its complications, 20 from cor pulmonale. The share of cardiac deaths was below expected in every five-year period except 1940-1944, when there were records of only 3 deaths. The authors concluded that the threshold limit for tremolite and anthophyllite needed reevaluation. Adequate smoking data were lacking.

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: Follow-up mortality study using proportional mortality. For lung and pleural cancer, gastrointestinal and peritoneal cancer, and cardiac disease, the share of deaths was compared with the expected share among United States white men. The reference year was 1955 for the total group and the median year for each five-year period.
• Who was studied: 260 talc workers in talc mines and mills. Each was employed in 1940 with 15 or more years of exposure to commercial talc dust, or reached 15 years of such exposure between 1940 and 1969. The authors were from the New York State Department of Labor. Autopsy or biopsy records were obtained for 38 of the 108 deaths.
• Exposure: Commercial talc dust, mainly talc, tremolite, anthophyllite and carbonate dusts, with a small amount of free silica. Among the 97 deaths with exposure data, mean exposure was 24.1 years (range 15 to 47 years).
• Main results:
  • There were 108 deaths among the 260 talc workers.
  • Of the 13 cancers of the lung and pleura, 12 were lung carcinomas and 1 was a fibrosarcoma of the pleura.
  • For lung and pleural cancer, overall proportional mortality was approximately four times that expected.
  • A significant increase in lung and pleural cancer appeared in the 60 to 79 age group rather than the 40 to 59 age group.
  • The difference between observed and expected lung and pleural cancer mortality was significant in 1950-54 (P<0.01) and not significant in 1960-64 and 1965-69.
  • For cancer of the gastrointestinal tract and peritoneum, there was no significant difference between observed and expected values, either overall or within age groups.
  • One of the 9 gastrointestinal and peritoneal cancers was a peritoneal mesothelioma.
  • There were 29 deaths from pneumoconiosis and its complications: 20 from cor pulmonale, 5 from advanced tuberculosis and 4 from bronchopneumonia. All 29 had first been exposed before 1945.
  • The percentage of deaths from pneumoconiosis and its complications fell by more than 50% in 1965-69 compared with the preceding period.
  • Observed proportional mortality from cardiac disease was lower than expected in every five-year period except the first (1940-1944).
  • Most respiratory cancers (10 of the 13) occurred in workers exposed 15 to 24 years.
• The authors' conclusion: The authors concluded that lung and pleural cancer mortality improved in 1960-69 after dust controls reduced dust counts, although fiber counts remained high. They stated that the present threshold limit for tremolite and anthophyllite needed reevaluation.
• Limitations the authors state:
  • Because of limits in the available data, a study by person-years of exposure was not feasible, so proportional mortality was used instead.
  • Without adequate smoking data, the role of smoking could not be assessed.
  • The number of gastrointestinal cancer deaths was too small to support any conclusion about risk by years of exposure.
  • No valid conclusion could be drawn about cardiac deaths in 1940-1944, because records of only 3 deaths were found for that period.
  • A longer interval is needed before the effect of dust controls on pneumoconiosis can be judged.

Topics

Medical terms in this study, explained in our Lexicon: Talc, Tremolite, Anthophyllite, Carcinoma, Peritoneal Mesothelioma, Pneumoconiosis, Cor Pulmonale.

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