Risk of Mortality from Respiratory Malignant and Non-Malignant Diseases among Talc Miners and Millers: A Systematic Review and Meta-Analysis

Our plain-English summary of Risk of Mortality from Respiratory Malignant and Non-Malignant Diseases among Talc Miners and Millers: A Systematic Review and Meta-Analysis, by C. Ciocan, A. Godono, S. Stefanin, et al (Toxics, 2022).

The study

• Authors: C. Ciocan, A. Godono, S. Stefanin, P. Boffetta, E. Pira, M. Clari
• Journal: Toxics
• Published: 2022;10(10)
• Type of article: Review
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

There is contrasting data on the association between talc exposure and lung and pleural cancer. Given the potential importance of this aspect, we performed a systematic review and meta-analysis to investigate the association between working in the talc extractive industry and mortality from malignant and non-malignant respiratory diseases. We followed PRISMA guidelines to systematically search for pertinent articles in three relevant electronic databases: Pubmed, Scopus, and WebOfScience, from their inception to 30 November 2021. The methodological quality of included articles was evaluated using the US National Institutes of Health tool. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) for malignant and non-malignant respiratory diseases as well as respective 95% confidence intervals (CIs) were extracted or calculated for each included cohort. Six articles comprising 7 cohorts were included in the metanalysis. There was increased mortality for pneumoconiosis, especially in the miner's group (SMR = 7.90, CI 95% 2.77-22.58) and especially in those exposed to higher quartz concentration and for non-malignant respiratory diseases in the overall analysis (SMR = 1.81, CI 95% 1.15-2.82). The risk for lung cancer mortality was slightly increased in the overall analysis (SMR = 1.42, CI 95% 1.07-1.89). The risk for malignant mesothelioma could not be calculated due to an insufficient number of studies assessing this outcome. This systematic review and meta-analysis provides evidence that men working in the talc mining industry have increased mortality for non-malignant respiratory diseases including pneumoconiosis. The small excess in lung cancer mortality may be, in part, explained by the high prevalence of the smokers in some of the analyzed cohorts or by the exposure to other carcinogens like radon decay products and diesel engine exhaust.

In plain English

This was a systematic review and meta-analysis that pooled earlier studies rather than collecting new data. The authors searched three databases up to 30 November 2021 and combined mortality results from six articles covering 7 cohorts: 5394 male talc miners and millers in Italy, Norway, France, Austria and the USA. Talc in some cohorts contained asbestos fibers such as tremolite and anthophyllite. Deaths from pneumoconiosis were higher than expected (pooled SMR 5.62, 95% CI 2.83–11.14), especially among miners (SMR 7.90, CI 2.77–22.58) and where quartz exceeded 1% of dust. Deaths from non-malignant respiratory diseases were also raised (SMR 1.81, CI 1.15–2.82). Lung cancer deaths were slightly raised (SMR 1.42, CI 1.07–1.89), with no dose-response pattern for quartz. The authors suggested smoking, radon decay products and diesel exhaust might partly explain this. Mesothelioma risk could not be calculated, and five mesothelioma deaths were reported across all cohorts. The authors concluded that talc mining and milling was positively associated with pneumoconiosis and non-malignant respiratory disease mortality. They noted the small number of studies and unreliable smoking data.

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: systematic review and meta-analysis of cohort studies and case-control studies nested in cohorts, using random-effects pooling of standardized mortality ratios (SMRs)
• Who was studied: 6 articles (published 1980 to 2022) covering 7 cohorts, a total of 5394 male talc miners and millers in Italy, Norway, France, Austria and the USA (2 cohorts from New York State, 1 from Vermont), with follow-up ranging from 28 to 74 years; databases searched up to 30 November 2021
• Exposure: work in the talc extractive industry (mining and milling), with exposure to talc dust and quartz (crystalline silica). Some cohorts' talc contained tremolite and anthophyllite, and the Norwegian cohort's talc contained only trace amounts of tremolite and anthophyllite. Polarized light microscopy of Austrian samples indicated asbestiform tremolite, chrysotile and anthophyllite.
• Main results:
  • Pneumoconiosis mortality, all cohorts pooled: SMR 5.62 (95% CI 2.83–11.14)
  • Pneumoconiosis mortality among miners: SMR 7.90 (95% CI 2.77–22.58); among millers the table gives SMR 2.64 (95% CI 1.40–4.96)
  • Pneumoconiosis mortality by quartz concentration: SMR 9.55 (95% CI 7.48–12.19) where quartz was above 1%, versus SMR 5.82 (95% CI 3.11–10.91) where quartz was below 1%
  • Non-malignant respiratory disease mortality, all cohorts pooled: SMR 1.81 (95% CI 1.15–2.82)
  • Lung cancer mortality, all cohorts pooled: SMR 1.42 (95% CI 1.07–1.89). There was no dose-response relation with quartz: SMR 1.56 (95% CI 0.60–4.02) where quartz was above 1%, versus SMR 1.27 (95% CI 1.01–1.60) where quartz was below 1%.
  • The authors suggested the slight lung cancer excess may in part be explained by high smoking prevalence in some cohorts, or by exposure to radon decay products and diesel engine exhaust
  • Mesothelioma risk could not be calculated because too few studies assessed it. Five mesothelioma deaths were reported across all cohorts. The authors stated the available data do not suggest an increased risk among talc miners and millers.
• The authors' conclusion: The authors concluded that the study supports a positive association between talc mining and milling and mortality from pneumoconiosis and non-malignant respiratory diseases
• Limitations the authors state:
  • The results rest on a small number of studies, because only a few cohorts of talc miners and millers exist worldwide
  • Smoking prevalence was high in the cohorts and smoking data covered only a reduced number of workers, so the data may not be reliable enough to assess whether smoking influenced the results

Topics

Medical terms in this study, explained in our Lexicon: Talc, Systematic Review, Meta-Analysis, Standardized Incidence Ratio (SIR), standardized mortality ratio (SMR), confidence interval, Pneumoconiosis, Lung Cancer.

Related studies

• Mortality in the cohort of talc miners and millers from Val Chisone, Northern Italy: 74 years of follow-up — C. Ciocan, E. Pira, et al. (2022)
• Mortality of Talc Miners and Millers From Val Chisone, Northern Italy: An Updated Cohort Study — E. Pira, M. Coggiola, et al. (2017)
• The association between occupational asbestos exposure with the risk of incidence and mortality from prostate cancer: a systematic review and meta-analysis — A. Godono, M. Clari, et al. (2022)
• An update of a mortality study of talc miners and millers in Italy — M. Coggiola, D. Bosio, et al. (2003)
• Evaluation of respiratory effects in miners and millers exposed to talc free of asbestos and silica — D.H. Wegman, J.M. Peters, et al. (1982)
• Mortality among talc miners and millers in New York State — M. Kleinfeld, J. Messite, et al. (1967)

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