Incidence, mortality, and disability-adjusted life years due to silicosis worldwide, 1990-2019: evidence from the global burden of disease study 2019.

Silicosis is an occupational lung disease because of exposure to silica dust in the workplace. Evidence on the spatiotemporal change of silicosis burden worldwide remains limited. This study utilized data extracted from the Global Burden of Disease Study 2019 to examine the numbers and age-standardized rates of incidence (ASIR), mortality (ASMR), and disability-adjusted life years (DALYs) caused by silicosis between 1990 and 2019. Average annual percentage changes (AAPCs) were calculated to evaluate the temporal trends of age-standardized indicators by sex, region, and socio-demographic index (SDI) since 1990. Results indicated an increase in new silicosis cases globally, rising by 64.61% from 84,426 in 1990 to 138,971 in 2019, with a sustained high number of DALYs attributed to this disease. Although the global age-standardized rates of incidence, mortality, and DALYs of silicosis have decreased since 1990, the number of new cases has increased in 168 countries and territories, and the ASIR of silicosis has also risen in 118 countries and territories, primarily in developing countries. Since 1990, the burden of silicosis among the elderly has significantly increased. Countries with higher SDI experienced a more rapid decline in the silicosis burden. Silicosis remains a public health problem that requires significant attention. Programs for prevention and elimination of this public health issue need to be established in more countries and territories. Protecting young workers from silica dust exposure is crucial to prevent the onset of silicosis in their later years and to reduce the disease burden among older workers.

Lung cancer risk and occupational pulmonary fibrosis: systematic review and meta-analysis.

BACKGROUND: Molecular pathways found to be important in pulmonary fibrosis are also involved in cancer pathogenesis, suggesting common pathways in the development of pulmonary fibrosis and lung cancer. RESEARCH QUESTION: Is pulmonary fibrosis from exposure to occupational carcinogens an independent risk factor for lung cancer? STUDY DESIGN AND METHODS: A comprehensive search of PubMed, Embase, Web of Science and Cochrane databases with over 100 search terms regarding occupational hazards causing pulmonary fibrosis was conducted. After screening and extraction, quality of evidence and eligibility criteria for meta-analysis were assessed. Meta-analysis was performed using a random-effects model. RESULTS: 52 studies were identified for systematic review. Meta-analysis of subgroups identified silicosis as a risk factor for lung cancer when investigating odds ratios for silicosis in autopsy studies (OR 1.47, 95% CI 1.13-1.90) and for lung cancer mortality in patients with silicosis (OR 3.21, 95% CI 2.67-3.87). Only considering studies with an adjustment for smoking as a confounder identified a significant increase in lung cancer risk (OR 1.58, 95% CI 1.34-1.87). However, due to a lack of studies including cumulative exposure, no adjustments could be included. In a qualitative review, no definitive conclusion could be reached for asbestosis and silicosis as independent risk factors for lung cancer, partly because the studies did not take cumulative exposure into account. INTERPRETATION: This systematic review confirms the current knowledge regarding asbestosis and silicosis, indicating a higher risk of lung cancer in exposed individuals compared to exposed workers without fibrosis. These individuals should be monitored for lung cancer, especially when asbestosis or silicosis is present.

Premature Deaths Due to Silicosis in Turkey, 2006-2017: A Twelve-Year Longitudinal Study.

BACKGROUND: Deaths due to epidemics of silicosis still continue to be reported both in developing and developed countries, and silica exposure from different sectors remains an important occupational health concern. AIMS: To identify characteristics of silicosis cases by focusing on a developing country and evaluate the frequency of and factors related to premature deaths and also reveal preventable causes of premature deaths in silicosis. STUDY DESIGN: Retrospective cohort. METHODS: We reviewed the records of 9769 patients who were diagnosed with occupational diseases in Istanbul Occupational Diseases Hospital between 2006 and 2017. According to International Classification of Diseases (ICD)-10 codes, 1473 silicosis cases were detected. The sociodemographic characteristics, job characteristics, comorbidities, serological, functional, and radiological data, and follow-up time were obtained from the medical records. Mortality data were gathered from The National Death Notification System of Ministry of Health. RESULTS: The study examined 9769 cases diagnosed with an occupational disease, and 15.0% (n = 1473) of them were diagnosed with silicosis. The median age of silicosis patients was 40.0 years, and 26.9% of them were child labor when they started to work in dusty industries. Child labor was mostly seen among dental technicians (57.7%), denim sandblasters (46.4%), and miners (37.0%). In the follow-up period, 26.3% of Teflon sandblasters, 11.1% of coal miners, 8.6% of denim sandblasters had died before their average life expectancy, and the years of loss of life was 26.0 ± 11.6 years all over the group. Premature death was associated with occupation [hazard ratio (Teflon sandblasting): 3.93, CI: 1.43-10.78; hazard ratio (marble production): 4.4, CI: 1.02-19.21]; large opacities in posterior anterior chest X-ray [hazard ratio: 2.14, CI: 1.18-3.86]; tuberculosis [hazard ratio: 2.60, CI: 1.42- 4.76]; and reduction in forced vital capacity (forced vital capacity% ≤80) during diagnosis [hazard ratio: 4.43, CI: 2.22-8.83]. CONCLUSION: More than a quarter of silicosis cases are those who start working in dusty industries at an early age. Factors associated with premature death in patients with silicosis are patient occupation, large opacities on chest X-ray, tuberculosis, and pulmonary function loss at diagnosis.

Mortality from silicosis in Brazil: Temporal trends in the period 1980-2017.

BACKGROUND: Silicosis is the most prevalent pneumoconiosis in Brazil. We aimed to estimate mortality rates and temporal trends for silicosis, and to identify areas of highest mortality. METHODS: Records of silicosis as the underlying (1980-2017) or contributory (2000-2017) cause of death in adults aged 20 years and older were retrieved from the Brazilian Mortality Database. Age-standardized mortality rates (ASMR) were calculated. The annual trend in ASMR was analyzed by joinpoint regression. Mortality rates per 100,000 person-years were calculated for each municipality. We analyzed temporal trends in municipalities where similar activities with exposure to silica were performed. RESULTS: There were 3164 death records (96.6% men) distributed over 14% of the municipalities. Mean age of death was 59.2 (SD 15.1) and mean ASMR was 0.085/100,000 (confidence interval 0.080-0.091). Joinpoint regression showed a significant increase in ASMR from 1980 to 2006 and a significant decrease after 2006 driven by a decline in deaths of individuals younger than 70 years. The highest mortality rate was 21.83/100,000 person-years, in a municipality with small mining operations for gems. Gold mining municipalities showed the highest composite death rate, 4.0/100,000 person-years. Tuberculosis was the main cause of death when silicosis was a contributing cause. CONCLUSIONS: In contrast with developed countries, silicosis mortality in Brazil increased to 2006 and subsequently started to drop, mostly from a plateau or decrease in deaths occurring in municipalities which regulated economic activities. However, this decrease did not occur in the older age group nor in the unregulated sector, the latter being the main challenge for exposure control and surveillance.

Transplantation for work-related lung disease in the USA.

OBJECTIVES: Work-related lung diseases (WRLDs) are entirely preventable. To assess the impact of WRLDs on the US transplant system, we identified adult lung transplant recipients with a WRLD diagnosis specified at the time of transplant to describe demographic, payer and clinical characteristics of these patients and to assess post-transplant survival. METHODS: Using US registry data from 1991 to 2018, we identified lung transplant recipients with WRLDs including coal workers' pneumoconiosis, silicosis, asbestosis, metal pneumoconiosis and berylliosis. RESULTS: The frequency of WRLD-associated transplants has increased over time. Among 230 lung transplants for WRLD, a majority were performed since 2009; 79 were for coal workers' pneumoconiosis and 78 were for silicosis. Patients with coal workers' pneumoconiosis were predominantly from West Virginia (n=31), Kentucky (n=23) or Virginia (n=10). States with the highest number of patients with silicosis transplant were Pennsylvania (n=12) and West Virginia (n=8). Patients with metal pneumoconiosis and asbestosis had the lowest and highest mean age at transplant (48.8 and 62.1 years). Median post-transplant survival was 8.2 years for patients with asbestosis, 6.6 years for coal workers' pneumoconiosis and 7.8 years for silicosis. Risk of death among patients with silicosis, coal workers' pneumoconiosis and asbestosis did not differ when compared with patients with idiopathic pulmonary fibrosis. CONCLUSIONS: Lung transplants for WRLDs are increasingly common, indicating a need for primary prevention and surveillance in high-risk occupations. Collection of patient occupational history by the registry could enhance case identification and inform prevention strategies.

Estimation of the number of workers exposed to respirable crystalline silica by industry: Analysis of OSHA compliance data (1979-2015).

BACKGROUND: Respirable crystalline silica (RCS) can potentially cause silicosis, lung cancer, and renal failure. The current study estimates the percentages of workers potentially overexposed to concentrations of RCS dust and silicosis proportional mortality rates (PMRs) by industry. METHODS: Occupational Safety and Health Administration compliance inspection sampling data for RCS collected during 1979 to 2015 were used to estimate percentages of workers exposed. The results were used in combination with US Census Bureau estimates to produce industry specific worker population estimates for 2014. Estimates of the numbers and percentages of workers exposed to RCS concentrations at least 1, 2, 5, and 10 times the National Institute for Occupational Safety and Health recommended exposure limit (REL) were calculated by industry using the 2002 North American Industry Classification System. Silicosis PMRs by industry were estimated using National Center for Health Statistics multiple cause of death data. RESULTS: RCS concentrations/workers exposed were highest in the poured concrete foundation and structure contractors; commercial and institutional building construction; and masonry contractors. Approximately 100 000 workers were exposed above the RCS REL, and most (79%) worked in the construction industry. Tile and terrazzo contractors (12%); brick, stone, and related construction merchant wholesalers (10%); masonry contractors (6%) and poured concrete foundation and structure contractors (6%) were the highest percentages of workers potentially overexposed. PMRs were highest for the structural clay product manufacturing and the foundries industries. CONCLUSION: Percentages of workers exposed to RCS varied by industry and in some industries workers are exposed over 10 times the REL. Exposures can be reduced below the REL by implementing the hierarchy of controls.

Silico-tuberculosis, silicosis and other respiratory morbidities among sandstone mine workers in Rajasthan- a cross-sectional study.

BACKGROUND: Exposures to respirable crystalline silica causes silicosis, pulmonary tuberculosis, chronic obstructive pulmonary disease, lung cancer, autoimmune disorders and chronic renal disease. The aim of this study was to find out the prevalence of silico-tuberculosis, silicosis and other respiratory morbidities in sandstone mine workers in Jodhpur district of Rajasthan. METHODS: It was a cross-sectional study done in sandstone mines in Jodhpur. A total of 15 mines were selected. The sample size was calculated and fixed to 174 mine workers. Chi-square and t-test were applied to draw inferences. RESULTS: The mean age of the mine workers was 39.13 ± 11.09 years. Three fourth (75.3%) of the workers were working for more than ten years in mines. Around 30.0% had a history of tuberculosis. Abnormal spirometry was found in 89.2% of workers. Around 42% of mine workers were found with abnormal chest x-rays. Prevalence of silicosis was 37.3%, silico-tuberculosis was 7.4%, tuberculosis was 10.0%, and other respiratory diseases like emphysema and pleural effusion were diagnosed among 4.3% workers. CONCLUSION: Prevalence of silico-tuberculosis, silicosis and other respiratory morbidities are high among sandstone mine workers.

Asbestosis and silicosis hospitalizations in Italy (2001-2015): results from the National Hospital Discharge Registry.

BACKGROUND: This work is aimed at evaluating the quality of Italian hospitalizations data about asbestosis and silicosis, assessing the impact of these diseases on the national health system and providing advice related to public health. METHODS: Italian hospital discharge data (2001-15) with diagnosis of asbestosis or silicosis were analysed by the multiple correspondence analysis and diseases epidemics were evaluated through hospitalization rates. RESULTS: Hospitalizations were concentrated in the northwestern area, referred mainly to males and oldest people, the most treated tumors were lung cancer and mesothelioma (for asbestosis) and cares were aimed at reducing symptoms and increasing blood oxygenation. Overall adjusted Italian hospitalization rates of asbestosis and silicosis were, respectively, 25.2 and 74.9 per 1 000 000 residents. With respect to asbestosis, hospitalizations treating silicosis reported doubled mortality (10.5 vs. 5.7%), longer stays (10.4 vs. 8.6 mean days) and older patients (77 vs. 72 years on average). Diseases rates reduced over time (with a steeper slope for silicosis) and in both fibroses increased hospital mortality (92.1% in asbestoses, 59.5% in silicoses) and percentage of urgent hospitalizations (116.0% in asbestoses, 56.6% in silicoses). CONCLUSION: Hospitalizations data regarding asbestosis and silicosis are consistent. Silicosis had a higher impact than asbestosis on the Italian health system. Although data show decreasing incidence of both fibroses, multiple correspondence analysis highlights that levels of illness severity were higher in silicosis and increased over time in both diseases. Further studies investigating the effectiveness of the current health surveillance programs concerning these diseases are suggested.

La prueba de la marcha de 6 minutos como factor pronóstico y de capacidad de ejercicio en pacientes con silicosis / The 6-Minute Walk Test as a Tool for Determining Exercise Capacity and Prognosis in Patients with Silicosis

Objetivo: Evaluar la capacidad de ejercicio, utilizando la prueba de la marcha de 6 minutos (6MWT), en pacientes con silicosis complicada, e identificar factores relacionados con dicho resultado, así como su valor pronóstico de hospitalización y mortalidad. Método: Estudio observacional prospectivo en 143 pacientes diagnosticados de silicosis complicada atendidos en consulta de neumología desde 2009 hasta diciembre 2016, sin limitación para hacer la 6MWT. Se evaluaron las pruebas de función pulmonar, los hallazgos de la tomografía computarizada y los parámetros de la 6MWT (distancia caminada y desaturación de oxígeno). Resultados: Los pacientes con silicosis complicada caminaban una media de 387 ± 92m. Los resultados fueron peores al aumentar la gravedad de la enfermedad; en silicosis A: 407 ± 97; B: 370 ± 88, y C: 357 ± 68 (p=0,022). La 6MWT mostraba una correlación positiva con la función pulmonar e inversa con la disnea (p < 0,001). Los pacientes con enfisema moderado/severo y un mayor tiempo con saturación nocturna de oxígeno por debajo del 90% presentaban resultados significativamente peores en la 6MWT. Los pacientes que caminaban < 350 m tenían más hospitalizaciones (3,7 ± 4,0) que los que caminaban>350 (1,1 ± 2,9). Los fallecidos al final del seguimiento caminaron 327,9 ± 73,0 frente a los que sobreviven, que caminaron 404,5 ± 89,7 m (p < 0,001). Conclusiones: Los valores de la espirometría y la categoría de la silicosis se relacionan con el resultado de la 6MWT, que resultó ser factor pronóstico para hospitalización y mortalidad. La 6MWT se perfila como una herramienta útil en salud ocupacional para el seguimiento de pacientes con silicosis

Objective: To evaluate exercise capacity using the 6-minute walk test (6MWT) in patients with complicated silicosis, and to determine how results shape the prognostic value of 6MWT for hospitalization and mortality. Method: Prospective observational study in 143 patients with complicated silicosis who performed the 6MWT in our outpatient pulmonology clinic between 2009 and the end of 2016. Lung function tests, computed tomography findings and 6MWT parameters (distance walked and oxygen desaturation) were evaluated. Results: Patients with complicated silicosis walked 387±92m. Results deteriorated as silicosis severity increased; category A: 407 ± 97m, B: 370±88m, and C: 357 ± 68m (P=.022). The 6MWT correlated positively with lung function and inversely with dyspnea determined by mMRC (P < .001). Patients with moderate/severe emphysema and greater CT90 presented a worse result on 6MWT. Patients who walked < 350m had more hospitalizations (3.7 ± 4.0) than those who walked > 350m (1.1 ± 2.9). There was an impact on survival: non-survivors walked 327.9 ± 73.0m, while survivors walked 404.5 ± 89.7m (P < .001). Conclusions: Spirometry values and category of complicated silicosis correlated with 6MWT and distance walked was a prognostic factor for hospitalization and mortality. The 6MWT is a useful tool in occupational health for monitoring patients with silicosis

The 6-Minute Walk Test as a Tool for Determining Exercise Capacity and Prognosis in Patients with Silicosis. / La prueba de la marcha de 6 minutos como factor pronóstico y de capacidad de ejercicio en pacientes con silicosis.

OBJECTIVE: To evaluate exercise capacity using the 6-minute walk test (6MWT) in patients with complicated silicosis, and to determine how results shape the prognostic value of 6MWT for hospitalization and mortality. METHOD: Prospective observational study in 143 patients with complicated silicosis who performed the 6MWT in our outpatient pulmonology clinic between 2009 and the end of 2016. Lung function tests, computed tomography findings and 6MWT parameters (distance walked and oxygen desaturation) were evaluated. RESULTS: Patients with complicated silicosis walked 387±92m. Results deteriorated as silicosis severity increased; category A: 407±97m, B: 370±88m, and C: 357±68m (P=.022). The 6MWT correlated positively with lung function and inversely with dyspnea determined by mMRC (P<.001). Patients with moderate/severe emphysema and greater CT90 presented a worse result on 6MWT. Patients who walked<350m had more hospitalizations (3.7±4.0) than those who walked>350m (1.1±2.9). There was an impact on survival: non-survivors walked 327.9±73.0m, while survivors walked 404.5±89.7m (P<.001). CONCLUSIONS: Spirometry values and category of complicated silicosis correlated with 6MWT and distance walked was a prognostic factor for hospitalization and mortality. The 6MWT is a useful tool in occupational health for monitoring patients with silicosis.

Precarious transition: a mortality study of South African ex-miners.

BACKGROUND: Despite their burden of a triple epidemic of silicosis, tuberculosis and HIV infection, little is known about the mortality experience of miners from the South African mining industry once they leave employment. Such information is important because of the size and dispersion of this population across a number of countries and the progressive nature of these diseases. METHODS: This study included 306,297 South African miners who left the industry during 2001-2013. The study aimed to calculate crude and standardised mortality rates, identify secular trends in mortality and model demographic and occupational risk factors for mortality. RESULTS: Crude mortality rates peaked in the first year after exit (32.8/1000 person-years), decreasing with each year from exit. Overall mortality was 20% higher than in the general population. Adjusted annual mortality halved over the 12 year period. Mortality predictors were being a black miner [adjusted hazard ratio (aHR) 3.30; 95% confidence interval (CI) 3.15-3.46]; underground work (aHR 1.33; 95% CI 1.28-1.39); and gold aHR 1.15 (95% CI 1.12-1.19) or multiple commodity employment (aHR 1.15; 95% CI 1.11-1.19). CONCLUSIONS: This is the first long-term mortality assessment in the large ex-miner population from the South African mining industry. Mortality patterns follow that of the national HIV-tuberculosis epidemic and antiretroviral treatment availability. However, ex-miners have further elevated mortality and a very high mortality risk in the year after leaving the workforce. Coordinated action between the mining industry, governments and non-governmental organisations is needed to reduce the impact of this precarious transition.

Clinical features of secondary spontaneous pneumothorax complicated with silicosis.

BACKGROUND: Few studies have focused on the management of secondary spontaneous pneumothorax (SSP) as a complication of pneumoconiosis. The aim of this study was to investigate the clinical features and therapeutic course of SSP associated with silicosis. METHODS: Between April 2005 and March 2015, 17 patients with silicosis underwent chest tube drainage for SSP in our institution. We retrospectively analyzed patient characteristics, type of treatment, clinical course, rate of recurrence, and survival time, and compared them with those of 30 patients diagnosed with chronic obstructive pulmonary disease (COPD) during the same period. RESULTS: Fourteen patients with silicosis had performance status score ≥ 2 and modified Medical Research Council Grade ≥ 2; these were significantly different from those in patients with COPD (P = 0.047, P = 0.026). Patients with silicosis had a significantly longer duration of chest tube placement and hospital stay. Recurrent pneumothorax occurred in 47.1% of patients with silicosis, which was not significantly different from the proportion of patients with COPD (40.9%, P = 0.843). However, in the silicosis group, patients treated with chest tube drainage alone tended to have a higher rate of ipsilateral recurrence than those who had pleurodesis, although this was not statistically significant. The median overall survival time of patients with silicosis was 82.6 months, while that of patients with COPD was 104.1 months. CONCLUSIONS: Patients with silicosis had worse physical status and respiratory functions at the time of occurrence of pneumothorax than those with COPD. Pleurodesis could be an effective treatment for SSP complicating silicosis.

What is expected in lung function after lung transplantation due to end-stage pulmonary silicosis?

In this study, we aimed to determine the impact of lung transplantation (LTx) on pulmonary function tests (PFTs) and survival among patients with end-stage silicosis. We included patients with end-stage silicosis on the wait list for LTx, between January 1989 and July 2015 (N = 26). Sixteen of these patients received LTx; 10 were eligible, but did not undergo LTx (non-LTx) during the study period. Retrospective information on PFTs (spirometry [volumes and flows], 6-minute walking test [6MWT], and DLCO) was retrieved from patients' medical charts, including baseline information for all patients and follow-up information for the LTx. At baseline, most patients presented with spirometric and 6MWT values that were suggestive of severe disease (FEV1 /FVC 76.5 ± 29.7; 6MWT 267.4 ± 104.5 m). Significant increases in these values were observed at follow-up in the LTx (P = .036 and .151, respectively). The overall median survival of patients in the LTx and non-LTx was 3.35 years (95% CI: 0.16-14.38) and 0.78 years (95% confidence interval [CI]: 0.12-3.65) (P = 0.002), respectively. For patients with end-stage silicosis, LTx offers significant benefits regarding pulmonary function and survival when compared to non-LTx, and is a reliable tool to help this critical population of patients, whose only treatment option is LTx.

Mortality of Talc Miners and Millers From Val Chisone, Northern Italy: An Updated Cohort Study.

OBJECTIVE: The aim of this study was to update the analysis of mortality of a cohort of talc miners and millers in Northern Italy. METHODS: We analyzed the mortality during 1946 to 2013 of 1722 male workers in an asbestos-free talc mine (1166 miners and 556 millers) employed during 1946 to 1995. RESULTS: The overall standardized mortality ratio (SMR) was 1.24 [95% confidence interval (95% CI) 1.17 to 1.32]; no deaths were observed from pleural cancer; mortality from lung cancer was not increased. Mortality from pneumoconiosis was increased (SMR 26.62; 95% CI 20.71 to 33.69), in particular among miners, and was associated with duration of employment and time since first employment. CONCLUSIONS: We confirmed the lack of association between exposure to asbestos-free talc, lung cancer, and mesothelioma. Increased mortality from pneumoconiosis among miners is attributable to past exposure to silica.

Surveillance for Silicosis Deaths Among Persons Aged 15-44 Years - United States, 1999-2015.

Silicosis is usually a disease of long latency affecting mostly older workers; therefore, silicosis deaths in young adults (aged 15-44 years) suggests acute or accelerated disease.* To understand the circumstances surrounding silicosis deaths among young persons, CDC analyzed the underlying and contributing causes† of death using multiple cause-of-death data (1999-2015) and industry and occupation information abstracted from death certificates (1999-2013). During 1999-2015, among 55 pneumoconiosis deaths of young adults with International Classification of Diseases, Tenth Revision (ICD-10) code J62 (pneumoconiosis due to dust containing silica),§ 38 (69%) had code J62.8 (pneumoconiosis due to other dust containing silica), and 17 (31%) had code J62.0 (pneumoconiosis due to talc dust) listed on their death certificate. Decedents whose cause of death code was J62.8 most frequently worked in the manufacturing and construction industries and production occupations where silica exposure is known to occur. Among the 17 decedents who had death certificates listing code J62.0 as cause of death, 13 had certificates with an underlying or a contributing cause of death code listed that indicated multiple drug use or drug overdose. In addition, 13 of the 17 death certificates listing code J62.0 as cause of death had information on decedent's industry and occupation; among the 13 decedents, none worked in talc exposure-associated jobs, suggesting that their talc exposure was nonoccupational. Examining detailed information on causes of death (including external causes) and industry and occupation of decedents is essential for identifying silicosis deaths associated with occupational exposures and reducing misclassification of silicosis mortality.

The social costs of uranium mining in the US Colorado Plateau cohort, 1960-2005.

OBJECTIVES: Long-term social costs associated with underground uranium mining are largely unknown. This study estimated health costs of Native American and white (Hispanic and non-Hispanic origin) uranium miners in the US Public Health Service Colorado Plateau cohort study. METHODS: Elevated uranium miner person-years of life lost (PYLL) were calculated from the most recent study of the Colorado Plateau cohort over 1960-2005. Nine causes of death categories were included. Costs to society of miner PYLL were monetized using the value of a statistical life-year approach. RESULTS: Costs over 1960-2005 totaled $2 billion USD [95% CI: $1.8, $2.2], or $2.9 million per elevated miner death. This corresponds to $43.1 million [95%: $38.7, $48.7] in annual costs. Lung cancer was the most costly cause of death at $1.4 billion [95%: $1.3, $1.5]. Absolute health costs were largest for white miners, but Native Americans had larger costs per elevated death. Annual excess mortality over 1960-2005 averaged 366.4 per 100,000 miners; 404.6 (white) and 201.5 per 100,000 (Native American). CONCLUSIONS: This research advances our understanding of uranium extraction legacy impacts, particularly among indigenous populations.

Silicosis mortality in Italy: temporal trends 1990-2012 and spatial patterns 2000-2012.

INTRODUCTION: The objective of this contribution is to describe, for the first time, occurrence, temporal trends and spatial patterns of mortality from silicosis in Italy in recent decades. METHODS: Mortality data on pneumoconiosis due to silica or silicates (ICD-9 code 502, ICD-10 code J62) were extracted from the Italian National Mortality Database. Temporal trends were analysed in the period 1990-2012; standardized rates per 100 000, spatial distribution, including cluster analysis, were computed for eleven years, i.e. 2000-2012 (2004-2005, data non available). RESULTS: In the period 1990-2012, a general decline in mortality was found with a total decrease of 74% and an estimated three year percentage change of -7.72. 4590 deaths from silicosis were observed in eleven years, 98% of them among men. The average age at death was 79.8 years. The mean age standardized rate was 0.33 (95% CI: 0.32 to 0.34). The Regions of Aosta Valley, Abruzzo and Sardinia had the highest rates. The assessment of risk at municipality level showed a significant excess of risk in 804 out of 8057 municipalities. Clusters of municipalities with a risk higher than expected were 34, observed in 18 out of 21 Regions. CONCLUSIONS: The study shows that mortality due to silicosis in Italy has steadily declined in the last decades, with differences among Regions. Clusters of municipalities with an excess of risk should be verified with Local Health Units in order to assess the need of targeted preventive actions.

Occupational exposure to silica dust and risk of lung cancer: an updated meta-analysis of epidemiological studies.

BACKGROUND: Crystalline silica is considered as one of the most common and serious occupational hazards to workers' health. Although its association with lung cancer has been studied for many decades, the conclusion remains somewhat controversial. Our objectives are to review and summarize the epidemiological evidence on the relationship between occupational silica exposure and risk of lung cancer and to provide an update on this major occupational health concern. METHODS: Eligible studies up to 29 April 2016 were identified. Pooled effect estimates were calculated according to the reported outcome and the study design. Cohort, case control and proportional mortality studies were examined separately. Studies reporting results according to silicotic status were grouped together and analyzed. Due to the significant amount of heterogeneity expected, random effects models were implemented. Subgroup and meta-regression analyses (both univariate and multivariate) were performed in an attempt to explain heterogeneity. Studies which had adequate exposure characterization were selected to find out whether there was an exposure-response relationship between silica and lung cancer. RESULTS: The risk of lung cancer was found to be elevated in both silicotics and non-silicotics. The pooled standardized mortality ratio (SMR) was 2.32 with a 95 % confidence interval (95 % CI) of 1.91-2.81 and 1.78 (95 % CI 1.07-2.96) respectively. The pooled standardized incidence ratio (SIR) was 2.49 (95 % CI 1.87-3.33) and 1.18 (95 % CI 0.86-1.62) respectively. Subgroup analysis showed that workers in the mining industry had the highest risk of lung cancer with a pooled SMR of 1.48 (95 % CI 1.18-1.86) and the weakest association was seen in potteries with a pooled SMR of 1.14 (95 % CI 1.05-1.23). A positive exposure-response relation was found between cumulative silica exposure and risk of lung cancer. CONCLUSION: The results of our meta-analysis supported the carcinogenic role of silica on the lungs, which was more pronounced at higher levels of exposure, in the presence of silicosis and in the mining industry. Further research is needed to evaluate whether non-silicotics are truly at risk, whether a predisposing factor would explain this potential risk, and to determine the mechanism of carcinogenicity of silica in humans.

38 years of autopsy findings in South African mine workers.

BACKGROUND: South African miners have a statutory right to autopsies for occupational lung disease compensation. These autopsies also provide information for research and surveillance. METHODS: Cardio-respiratory organs are removed where miners die and are examined at the National Institute for Occupational Health. We extracted data from the PATHAUT database and described key demographic, exposure and disease trends (1975-2013). RESULTS: Of 109,101 autopsies, 72,348 (66.3%) were black, and 34,794 (31.9%) were white miners. Autopsies declined from over 3,000 (1975-1998) to 1,118 in 2013. Most were gold miners (74.0%). 78.6% black and 13.2% white miners died while in employment. Overall proportions of silicosis and pulmonary tuberculosis were 12.0% and 13.0% in black, and 20.5% and 2.4% in white miners, respectively. Disease increased over time. CONCLUSIONS: High levels of disease persist. Black ex-miners are underrepresented, indicating a need for strategies to improve awareness and provision of autopsy facilities in labor-sending areas.

An approach to adjust standardized mortality ratios for competing cause of death in cohort studies.

PURPOSE: The calculation of standardized mortality ratios (SMRs) is a standard tool for the estimation of health risks in occupational epidemiology. An increasing number of studies deal with the analysis of the mortality in employees suffering from an occupational disease like silicosis or coal-worker pneumoconiosis (CWP). Their focus lies not on the mortality risk due to the occupational disease itself, but on other diseases such as lung cancer or heart diseases. Using population-based reference rates in these studies can cause misleading results because mortality rates of the general population do not reflect the elevated mortality due to the occupational disease investigated. Hence, the purpose of the present paper is to develop an approach to adjust the risk estimates for other causes of death with respect to the effect of an occupational disease as a competing cause of death in occupational mortality cohort studies. METHODS: To overcome the problems associated with SMRs, the paper makes use of proportional mortality ratios (PMR), which are a further approach for the estimation of health risks in occupational epidemiology. The cause-specific SMR can be rewritten as a product of PMR times the overall SMR. The PMR can be adjusted by ignoring the competing cause of death. Hence, an adjusted cause-specific SMR can be derived by multiplying this adjusted PMR with the overall SMR. This approach is applied to studies concerning lung cancer risk in coal miners suffering from CWP. RESULTS AND CONCLUSIONS: The usual approach for calculating SMRs leads to an underestimation of the real lung cancer risk in subgroups of miners suffering from CWP. The same effect can be observed in workers exposed to respirable silica already suffering from silicosis. The presented approach results in more realistic risk estimation in mortality cohort studies of employees suffering from an occupational disease. It is easily calculable on the basis of usually published values of observed cases and the corresponding cause-specific SMR.