Documents crystalline silica 49 results

"Objectives
Crystalline silica is found in many construction materials. Although it is one of the oldest known occupational exposures, new exposure contexts have emerged in recent years. In 2021, France classified work involving exposure to respirable crystalline silica (ie, silica dust) generated by a work process as carcinogenic. In order to assess exposure in the French workforce between 1947 and 2020, we developed a silica job-exposure matrix (JEM) for the Matgéné program.
Method
The JEM was linked with occupational data from different population censuses (1982, 1990, 1999, 2007 and 2017). The proportions and numbers of workers exposed to silica dust in France at these various census time points were estimated and described by sex and industry for 2017.
Results
After decreasing between 1982 and 1999, the proportion of workers exposed to silica dust remained stable at 4%, representing 975 000 workers in 2017. Exposed workers were mostly men (93%), and most worked in the construction industry (64%). This was also the industry where the majority of workers were exposed to a level above the French 8-hour time weighted average occupational exposure limit (TWA-OEL).
Conclusion
A large number of workers in France were still exposed (some highly) to silica dust in 2017 so this agent still poses an occupational health concern. The results of this study provide key information about the continued surveillance of the evolution of exposure to silica dust. In a few years, it will be possible to quantify the impact of the 2021 regulation in terms of proportions and number of workers exposed to silica dust."

"Objectives
The quantitative job-exposure matrix SYN-JEM consists of various dimensions: job-specific estimates, region-specific estimates, and prior expert ratings of jobs by the semi-quantitative DOM-JEM. We analyzed the effect of different JEM dimensions on the exposure–response relationships between occupational silica exposure and lung cancer risk to investigate how these variations influence estimates of exposure by a quantitative JEM and associated health endpoints.
Methods
Using SYN-JEM, and alternative SYN-JEM specifications with varying dimensions included, cumulative silica exposure estimates were assigned to 16 901 lung cancer cases and 20 965 controls pooled from 14 international community-based case-control studies. Exposure–response relationships based on SYN-JEM and alternative SYN-JEM specifications were analyzed using regression analyses (by quartiles and log-transformed continuous silica exposure) and generalized additive models (GAM), adjusted for age, sex, study, cigarette pack-years, time since quitting smoking, and ever employment in occupations with established lung cancer risk.
Results
SYN-JEM and alternative specifications generated overall elevated and similar lung cancer odds ratios ranging from 1.13 (1st quartile) to 1.50 (4th quartile). In the categorical and log-linear analyses SYN-JEM with all dimensions included yielded the best model fit, and exclusion of job-specific estimates from SYN-JEM yielded the poorest model fit. Additionally, GAM showed the poorest model fit when excluding job-specific estimates.
Conclusion
The established exposure–response relationship between occupational silica exposure and lung cancer was marginally influenced by varying the dimensions of SYN-JEM. Optimized modelling of exposure–response relationships will be obtained when incorporating all relevant dimensions, namely prior rating, job, time, and region. Quantitative job-specific estimates appeared to be the most prominent dimension for this general population JEM."

"Objectives:
To quantify, after extending follow-up 15 years, the relationship between occupational respirable crystalline silica (RCS) exposure and risk of silicosis diagnosis and lung cancer mortality in the German Porcelain Workers Cohort Study, and to estimate possible exposure thresholds for these.
Methods:
Porcelain workers enrolled between January 1, 1985, and December 31, 1987, in a mandatory medical surveillance program including triennial chest x-rays and alive at the end of the previous study follow-up (2005) were followed through December 2020, for lung cancer mortality and silicosis incidence. Cause of death was determined from death certificates. Silicosis cases were identified by re-reading x-rays of individuals remaining in the medical surveillance program or filing insurance claims for silicosis. RCS exposure was estimated for each cohort member using a job exposure matrix (JEM) based on about 8,000 historical industrial hygiene RCS measurements. Cause-specific standardized mortality ratios (SMRs) and Cox proportional hazards ratios (HRs) and their 95% confidence intervals (95% CIs) were estimated by cumulative and average exposure groups, controlling for age, sex, smoking status and employment duration. Exposure-response analyses were performed to identify possible exposure thresholds for lung cancer and silicosis risk.
Results:
Total deaths increased from 1,610 (9.1%) to 4,586 (26%) over 537,129 total person-years at risk. All-cause mortality was elevated among men (SMR = 1.10, 95% CI 1.06–1.14); however, a deficit was seen among women (SMR = 0.93, 95% CI 0.89–0.98). No statistically significantly increased mortality was seen due to lung cancer, renal cancer, or non-malignant renal disease – conditions reportedly associated with RCS exposure. Lung cancer mortality was unrelated to RCS exposure level. However, for silicosis cases classified using International Labor Organization (ILO) categories ≥1/1 or 1/0, risk was strongly associated with estimated average exposure >0.10 mg/m3 and 0.15 mg/m3, and cumulative exposure >3.0 mg/m3-years and > 1.0 mg/m3-years, respectively.
Conclusion:
Despite the large number (n = 284) of lung cancer deaths and high historical RCS exposures, no excess risk and no relationship with exposure level were seen. However, RCS exposure was strongly associated with silicosis risk, with clear exposure thresholds. This study further confirms the lack of increased lung cancer risk at RCS levels historically prevalent in the German porcelain industry and that exposures exceeding estimated thresholds clearly increased silicosis risk. Occupational exposure levels in the German porcelain industry in recent decades have remained well below these thresholds; therefore, few additional silicosis cases are expected."

This work is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

"Silicosis, a debilitating occupational lung disease caused by inhaling crystalline silica, continues to be a significant global health issue, especially with the increasing use of engineered stone (ES) surfaces containing high silica content. Traditional diagnostic methods, dependent on radiological interpretation, have low sensitivity, especially, in the early stages of the disease, and present variability between evaluators. This study explores the efficacy of deep learning techniques in automating the screening and staging of silicosis using chest X-ray images.
Utilizing a comprehensive dataset, obtained from the medical records of a cohort of workers exposed to artificial quartz conglomerates, we implemented a preprocessing stage for rib-cage segmentation, followed by classification using state-of-the-art deep learning models. The segmentation model exhibited high precision, ensuring accurate identification of thoracic structures. In the screening phase, our models achieved near-perfect accuracy, with ROC AUC values reaching 1.0, effectively distinguishing between healthy individuals and those with silicosis.
The models demonstrated remarkable precision in the staging of the disease. Nevertheless, differentiating between simple silicosis and progressive massive fibrosis, the evolved and complicated form of the disease, presented certain difficulties, especially during the transitional period, when assessment can be significantly subjective. Notwithstanding these difficulties, the models achieved an accuracy of around 81% and ROC AUC scores nearing 0.93.
This study highlights the potential of deep learning to generate clinical decision support tools to increase the accuracy and effectiveness in the diagnosis and staging of silicosis, whose early detection would allow the patient to be moved away from all sources of occupational exposure, therefore constituting a substantial advancement in occupational health diagnostics."

This work is licensed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/).

"Background:
Crystalline silica is a human carcinogen and its use is widespread among construction, mining, foundries, and other manufacturing industries.
Purpose:
To evaluate occupational exposure to crystalline silica in Italy.
Methods:
Data were collected from exposure registries and descriptive statistics were calculated for exposure-related variables. The number of potentially exposed workers was estimated in a subset of industrial sectors. Linear mixed model analysis was performed to determine factors affecting the exposure level.
Results:
We found 1387 cases of crystalline silica exposure between 1996 and 2012. Exposure was most common in construction work (AM?=?0·057 mg/m3, N?=?505), and among miners and quarry workers (AM?=?0·048 mg/m3, N?=?238). We estimated that 41?643 workers were at risk of exposure in the selected industrial sectors during the same period.
Conclusions:
This study identified high-risk sectors for occupational exposure to crystalline silica, which can help guide targeted dust control interventions and health promotion campaigns in the workplace."

"Research suggests that in Britain nearly 800 people die a year from lung cancer caused by breathing in silica dust at work. In the European Union, around 7,000 cases of lung cancer are caused by this carcinogen annually. Worldwide, it's estimated that millions of employees are exposed to silica dust.
Silica dust is created when the ‘crystalline silica' in materials such as stone, mortar or tiles is broken down and released. It happens when you drill, saw, cut, grind or sand the products – or work on them in any way that disturbs the natural silica content."

"This Volume 100C covers Arsenic, Metals, Fibres, and Dusts, specifically Arsenic and Arsenic Compounds, Beryllium and Beryllium Compounds, Cadmium and Cadmium Compounds, Chromium (VI) Compounds, Nickel and Nickel Compounds, Asbestos (Chrysotile, Amosite, Crocidolite, Tremolite, Actinolite and Anthophyllite), Erionite, Leather Dust, Silica Dust, Crystalline, in the form of Quartz or Cristobalite, and Wood Dust.
Because the scope of Volume 100 is so broad, its Monographs are focused on key information. Each Monograph presents a description of a carcinogenic agent and how people are exposed, critical overviews of the epidemiological studies and animal cancer bioassays, and a concise review of the agent's toxicokinetics, plausible mechanisms of carcinogenesis, and potentially susceptible populations, and life-stages. Details of the design and results of individual epidemiological studies and animal cancer bioassays are summarized in tables. Short tables that highlight key results are printed in Volume 100, and more extensive tables that include all studies appear on the Monographs programme website (http://monographs.iarc.fr).

It is hoped that this volume, by compiling the knowledge accumulated through several decades of cancer research, will stimulate cancer prevention activities worldwide, and will be a valued resource for future research to identify other agents suspected of causing cancer in humans. "

"The objective of this guide is to give producers and users of products and materials that contain crystalline silica guidance on the practical application of a programme to manage respirable crystalline silica and guidance on the safe use of crystalline silica containing products in the workplace. The silica producing and using industries stress that employees should be protected against potential health effects caused by occupational exposure to respirable crystalline silica in the workplace. Therefore efforts should be focused on minimising potential personal exposure to respirable crystalline silica in the workplace.This is a dynamic guide, which concentrates on the aspects that are considered the most significant. Although comprehensive, it has not been possible to cover in detail all areas of concern. Users, customers, workers, and readers are advised to consult occupational health professionals and other experts concerning all matters regarding control of respirable crystalline silica in each specific workplace."
(Extract from the Preamble)