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

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.