Mortality in the cohort of talc miners and millers from Val Chisone, Northern Italy: 74 years of follow-up

Our plain-English summary of Mortality in the cohort of talc miners and millers from Val Chisone, Northern Italy: 74 years of follow-up, by C. Ciocan, E. Pira, M. Coggiola, et al (Environmental Research, 2022).

The study

• Authors: C. Ciocan, E. Pira, M. Coggiola, N. Franco, A. Godono, C. La Vecchia, E. Negri, P. Boffetta
• Journal: Environmental Research
• Published: 2022;203:111865
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To update the analysis of mortality of a cohort of talc miners and millers in Northern Italy.

Methods: We analyzed overall mortality and mortality from specific causes of death during 1946-2020 of 1749 male workers in a talc mine where asbestos was not detected (1184 miners and 565 millers) employed during 1946-1995.

Results: The overall standardized mortality ratio (SMR) was 1.21 (95 % confidence interval [CI] 1.14-1.28); no deaths were observed from pleural cancer. Mortality from lung cancer was not increased (SMR = 1.02 95 % CI 0.82-1.27), while mortality from pneumoconiosis was (SMR 9.55; 95 % CI 7.43-12.08), especially among miners (SMR 12.74; 95 % CI 9.79-16.31). There was a trend in risk of pneumoconiosis with increasing duration of employment in the overall cohort, and the SMR for 25+ years of employment was 15.12 (95 % CI 10.89-20.43).

Conclusions: This uniquely long-term follow up confirms the results of previous analyses, namely the lack of association between exposure to talc with no detectable level of asbestos and lung cancer and mesothelioma. Increased mortality from pneumoconiosis among miners is related to past exposure to silica.

Copyright © 2021. Published by Elsevier Inc.

In plain English

The authors updated a mortality study of 1,749 men (1,184 miners, 565 millers) employed in 1946 to 1995 at a talc mine and mill in Val Chisone, Northern Italy, followed to January 2020. The authors describe this talc as having no detectable asbestos; samples collected in 2017 to 2020 showed no asbestos fibers. Workers were also exposed to silica, and miners to radon. Deaths from all causes were higher than expected (SMR 1.21, 95% CI 1.14 to 1.28). No pleural cancer deaths occurred, against 2.8 expected. Two peritoneal cancer deaths were one peritoneal carcinomatosis and one retroperitoneal tumor. Lung cancer deaths were not increased (SMR 1.02, 95% CI 0.82 to 1.27). Pneumoconiosis deaths were raised (69 deaths; SMR 9.55, 95% CI 7.43 to 12.1), especially among miners (SMR 12.75, 95% CI 9.80 to 16.31), and rose with years worked. The authors concluded that talc with no detectable asbestos was not associated with lung cancer or mesothelioma, and attributed pneumoconiosis to past silica exposure. Stated limitations included no individual exposure data, little information on alcohol drinking, and unvalidated causes of death.

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: Retrospective cohort mortality study (updated follow-up of a previously studied cohort). Observed deaths were compared with expected deaths from national and regional male death rates (standardized mortality ratios).
• Who was studied: 1749 men (1184 miners and 565 millers) employed for at least one month at a talc mine or mill in Val Chisone, Northern Italy, between 1946 and 1995. They were followed from 1946 (or first employment) to January 31, 2020, with follow-up stopped at age 85. 37 women were excluded. At the end of follow-up, 321 were alive, 1346 had died (90 from an unknown cause), and 82 were lost to follow-up.
• Exposure: Talc described by the authors as having no detectable level of asbestos. Miners were also exposed to silica, mining gases and radon, and from 1991 to diesel engine emissions. Millers were exposed to talc and to silica as a potential contaminant of talc. 25 talc samples collected in 2017 to 2020 and examined by scanning electron microscopy showed no asbestos fibers; the stated limit of detection was 569 fibers per mg.
• Main results:
  • Whole cohort: mortality from all causes was higher than expected, SMR 1.21 (95% CI 1.14 to 1.28), based on 1174 observed vs 969.6 expected deaths. All cancers combined were not in excess (SMR 1.00, 95% CI 0.89 to 1.12 in Table 1).
  • Whole cohort: no deaths from pleural cancer were observed (2.8 expected). Two deaths from peritoneal cancer were observed (1.4 expected); on review of medical records, one was a peritoneal carcinomatosis and one a retroperitoneal tumor. Among men who died after age 85, who were excluded from the analysis, there were no pleural or peritoneal cancer deaths.
  • Whole cohort: lung cancer mortality was not increased, SMR 1.02 (95% CI 0.82 to 1.27), based on 85 observed vs 83.0 expected deaths. Miners had an SMR of 1.01 (0.76 to 1.31) and millers 1.06 (0.71 to 1.52).
  • Whole cohort: pneumoconiosis mortality was increased, based on 69 observed vs 7.2 expected deaths. Table 1 and the abstract give SMR 9.55 (95% CI 7.43 to 12.1); the results text gives SMR 9.58 (95% CI 7.43 to 12.08).
  • Pneumoconiosis by job: miners SMR 12.75 (95% CI 9.80 to 16.31; 63 observed deaths); millers SMR 2.63 (95% CI 0.96 to 5.73; 6 observed deaths); p for heterogeneity less than 0.0001.
  • Pneumoconiosis by duration of employment: SMR 4.19 (2.09 to 7.50) for less than 15 years, 8.78 (5.02 to 14.3) for 15 to 24 years, and 15.1 (10.9 to 20.4) for 25 or more years (p for trend less than 0.0001).
  • Non-malignant respiratory diseases: the excess was mainly due to pneumoconiosis. After excluding pneumoconiosis deaths, the SMR was 0.85 (95% CI 0.68 to 1.06). For chronic obstructive pulmonary disease, the SMR was 0.92 (0.66 to 1.26).
  • Whole cohort: excess mortality was found for oral and pharyngeal cancer (SMR 3.65, 95% CI 2.52 to 5.10), esophageal cancer (SMR 1.91, 95% CI 1.04 to 3.21) and liver cirrhosis (SMR 1.88, 95% CI 1.46 to 2.39). The authors considered this likely related to increased alcohol consumption.
• The authors' conclusion: The authors concluded that they confirmed earlier findings of no association between exposure to talc with no detectable level of asbestos and lung cancer or malignant mesothelioma. They wrote that the increased mortality from non-malignant respiratory diseases can likely be attributed to past silica exposure.
• Limitations the authors state:
  • There were no individual exposure data.
  • There was a lack of detailed information on potential confounders such as alcohol drinking.
  • Causes of death were not validated, and there was no information on illness (morbidity).
  • 4.7% of subjects were lost to follow-up, and 6.7% of deceased subjects had an unknown cause of death.
  • The cohort included no women, so the study cannot address ovarian cancer.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Talc and vermiculite.

Medical terms in this study, explained in our Lexicon: Talc, standardized mortality ratio (SMR), confidence interval, Lung Cancer, Pneumoconiosis, Mesothelioma.

Related studies

• Mortality of Talc Miners and Millers From Val Chisone, Northern Italy: An Updated Cohort Study — E. Pira, M. Coggiola, et al. (2017)
• An update of a mortality study of talc miners and millers in Italy — M. Coggiola, D. Bosio, et al. (2003)
• An update of cancer mortality among chrysotile asbestos miners in Balangero, northern Italy — G. Piolatto, E. Negri, et al. (1990)
• Absence of mesothelioma risk maintained in an expanded international cohort of cosmetic talc miners and millers — A.M. Ierardi, G.M. Marsh (2020)
• Confidence interval function analysis to evaluate the risk of mesothelioma among an expanded international cohort of cosmetic talc miners and millers — G.M. Marsh, A.M. Ierardi (2020)
• Mortality among talc miners and millers in New York State — M. Kleinfeld, J. Messite, et al. (1967)

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