Silicosis and coal workers' pneumoconiosis

Exposure to coal mine dust and/or crystalline silica results in pneumoconiosis with initiation and progression of pulmonary fibrosis. This review presents characteristics of simple and complicated coal workers' pneumoconiosis (CWP) as well as pathologic indices of acute and chronic silicosis by summarizing results of in vitro, animal, and human investigations. These results support four basic mechanisms in the etiology of CWP and silicosis: a) direct cytotoxicity of coal dust or silica, resulting in lung cell damage, release of lipases and proteases, and eventual lung scarring; b) activation of oxidant production by pulmonary phagocytes, which overwhelms the antioxidant defenses and leads to lipid peroxidation, protein nitrosation, cell injury, and lung scarring; c) activation of mediator release from alveolar macrophages and epithelial cells, which leads to recruitment of polymorphonuclear leukocytes and macrophages, resulting in the production of proinflammatory cytokines and reactive species and in further lung injury and scarring; d) secretion of growth factors from alveolar macrophages and epithelial cells, stimulating fibroblast proliferation and eventual scarring. Results of in vitro and animal studies provide a basis for proposing these mechanisms for the initiation and progression of pneumoconiosis. Data obtained from exposed workers lend support to these mechanisms.     

Recent trends of age-specific pneumoconiosis mortality rates in the United States, 1985-1996: coal workers' pneumoconiosis, asbestosis, and silicosis

The authors examined the temporal trends of age-specific pneumoconiosis mortality from coal worker's pneumoconiosis (CWP), asbestosis, and silicosis in the United States in 1985-1996. Mortality data were derived from the National Center for Health Statistics multiple causes of death files for the period. Age-specific mortality rates were computed for three age groups (15-44, 45-64, and > or = 65 years) among decedents with mention of CWP, asbestosis, or silicosis. Linear regression analysis was performed to examine the annual changes in age-specific mortality rates, by age group, with each specific condition. The CWP mortality rates declined significantly (p = 0.0001) in the groups 45 years old and older, but not in the age group 15-44. Asbestosis mortality rates declined significantly (p = 0.005) for the age group 45-64, while increasing (p = 0.0001) for those aged 65 years and older. However, in the younger age group 15-44, the rates showed no significant trend. Silicosis mortality rates declined significantly (p = 0.0001) for all groups. The continued occurrence of deaths from CWP, asbestosis, and silicosis among young adults may be the result of high levels of exposure to occupational risks. These results suggest that pneumoconiosis surveillance may help to evaluate the temporal pneumoconiosis mortality patterns in the United States.     

Progression on the prevention of coal workers' pneumoconiosis

通过收集、分析国内、外相关的文献资料,了解煤工尘肺的预防及治疗进展.我国煤工尘肺职业病防治形势严峻.煤工尘肺防治技术还需提高.必须提高煤工尘肺预防与治疗技术水平,增强用人单位及劳动者的防护意识,达到降低煤矿职业病发病率、提高煤工尘肺患者生存质量目的.     

各期煤工尘肺病患者骨密度变化分析

目的 分析不同期别煤工尘肺病患者全身不同部位骨密度变化情况.方法 晋城煤业集团Ⅰ～Ⅲ期煤工尘肺病患者120例,均为男性,年龄55～80岁,平均67岁.采用全身双能X线骨密度仪进行全身各部位骨密度测定及T值,分析各组骨密度值变化情况,并根据T值观察各组患者骨质流失及骨质疏松发生率.结果 与对照组比较,Ⅱ期煤工尘肺组仅胸部骨、骨盆、脊柱较对照组骨密度明显下降,差异有统计学意义(P＜0.05);Ⅲ期煤工尘肺组全身各个部位骨密度均较对照组明显下降,差异有统计学意义(P＜0.05).结论 随着煤工尘肺严重程度增加,患者全身骨密度值明显下降,且骨质流失及骨质疏松发生率明显升高.     

鄂尔多斯市煤工尘肺发病情况

目的 探讨鄂尔多斯市煤工尘肺发病情况,为进一步加强煤工尘肺防治和管理提供科学依据.方法 选择从事煤炭行业一线作业工人,采用x2检验、秩和检验分析不同接尘工龄、工种尘肺病发生情况.结果 该市煤类行业2011年进行企业健康检查,资料完整的共9 230人,检出尘肺病61例,煤工尘肺发生率为0.66％;掘进工种煤工尘肺发生率(1.11％)明显高于采煤工(0.64％)和辅助工(0.10％),差异有统计学意义(P＜0.05);接尘工龄≥30 a的煤工尘肺发生率最高,差异有统计学意义(P＜0.05).结论 该市煤炭行业尘肺发生率较低,从事掘进工作和接尘工龄长的煤矿工人煤工尘肺发生率高.     

Longitudinal study of the radiology of coal workers' pneumoconiosis

Summary In fifteen hundred sixty-one radiographs from 318 coal workers with different grades of pneumoconiosis, the prevalence of perinodular, perinodal, and generalized emphysema has been examined. Furthermore, the prevalence of enlarged hili was determined. These data have been correlated with age and the type, number and density of small pneumoconiotic opacities and with the size and localization of large pneumoconiotic opacities.Some form of emphysema was found in 86.7% of all radiographs, most frequently in the form of generalized emphysema (63.6%). The prevalence increases with severity of pneumoconiosis. The same holds for enlarged hili.With support of the European Communities, Luxembourg     

Gene polymorphisms of fibrinolytic enzymes in coal workers' pneumoconiosis

The authors assessed the gene polymorphisms of missense C/T polymorphism in exon 6 of the urokinase-plasminogen activator (PLAU) gene (PLAU P141L), Alu-repeat in intron 8 of the tissue-type plasminogen activator (PLAT) gene (PLAT TPA25 Alu insertion), and 4G/5G in the promoter region of the serine proteinase inhibitor, clade E (SERPINE) or plasminogen activator inhibitor type 1 gene (SERPINE1 -675 4G/5G) in 153 healthy volunteers and 154 retired coal miners with coal miners' pneumoconiosis (CWP). The CWP subjects included 94 individuals with simple pneumoconiosis and 60 individuals with progressive massive fibrosis presenting with worse pulmonary function. The distributions of genotypes of these three genes did not differ between the control and CWP subjects or between subjects with simple pneumoconiosis and those with progressive massive fibrosis. However, by assessing duration of work and its interaction with genotypes by means of logistic regression, the authors found the missense C/T polymorphism in exon 6 of the PLAU gene to be an effect modifier of the association between work duration and the development of progressive massive fibrosis.     

山西某煤矿煤工尘肺发病规律分析

目的通过分析大同某煤矿不同工种、不同开始接尘年代的接尘工人档案资料, 揭示煤工尘肺发病规律。方法收集该煤矿1970年以来进入研究队列的4 771名煤矿工人作为研究对象, 随访42年, 分析不同工种、不同开始接尘年代的接尘工人发病率及各队列累计发病率。结果符合纳入标准共4 771人, 其中患者193人, 非患者4 578人, 粗发病率为4.05%;掘进工、采煤工、混合工及辅助工的发病率依次为25.10%、8.50%、3.60%、0.19%, 不同工种之间差异有统计学意义(χ²=644.12, P<0.001);在相同的42年观察期内, 掘进工、采煤工、混合工和辅助工的累计发病率分别为84.25%、41.04%、33.60%及1.03%, 不同工种间累计发病率差异有统计学意义(χ²=543.73, P<0.001);在相同32年观察期内, 1970～及1980～开始接尘年代累计发病率分别为13.56%及13.51%, 不同开始接尘年代累计发病率之间差异有统计学意义(χ²=217.12, P<0.001)。结论掘进工累计发病率高于采煤工、混合工和辅助工;随着开始接尘年代的推移, 接尘工人累计发病率有下降趋势。     

某煤矿煤工尘肺合并肺结核现况调查及发病影响因素研究

目的 调查淮南矿业集团下属某煤矿煤工尘肺(CWP)合并肺结核的流行状况及其影响因素,为CWP结核的防治提供依据.方法 收集最近3个月内417例健在CWP患者的健康监护资料,采用统一的调查袁对患者进行问卷调查.受检率为85.61%.将所得资料用Excel 2003建立数据库,以SPSS 13.0 for windows统计软件包进行统计学分析.结果 ①该矿CWP合并肺结核的患病率为5.3%;②CWP合并结核与尘肺期别呈正相关(r=0.26,P<0.001),随着CWP期别增加,结核合并率亦增加;③该矿最大发病年龄为83.1岁,最小26.2岁.4个发病年龄组χ3检验差异无显著性(P>0.05);④单因素奈件logistic回归分析显示文化程度、蛋类摄入、卡痕和肺结核接触史等具有显著意义.其OR值分别为0.56、0.54、0..13、0.30(P<0.05);⑤多因素条件logistic回归分析,除肺结核接触史外,上述因素进入回归方程.结论 CWP易并发结核,CWP合并结核的发生与病人的文化程度、蛋类摄入、卡痕数密切相关.     

Exercise capacity in coal workers' pneumoconiosis: an analysis using causal modelling

Miners disabled from black lung disease (coal workers' pneumoconiosis, CWP) are entitled to disability benefits under United States federal and state laws. The determination of disability currently involves several scientific controversies. The Federal Department of Labor states that one second forced vital capacity (FEV1) is an important marker of disability from CWP. The Department of Labor also states that disability may occur in simple CWP, in the absence of progressive massive fibrosis (PMF). Both these contentions may reasonably be challenged. To investigate these issues, and to investigate the relation between exercise tolerance and several other variables, including age, weight, radiographic findings, and exposure to mining and smoking, we studied 690 miners. Simple correlation analysis was not helpful because many variables were correlated with each other. Linear regression analysis led to conclusions that were thought to be misleading. Causal modelling provided an analysis that appeared to be most explanatory. In the model tested years of coal mining did not affect FEV1; if this conclusion is substantiated by others FEV1 should be eliminated as an indicator of disability from CWP as it is not related to mining experience. On the other hand, the Department of Labor's position that disability may occur in simple CWP seems reasonable, as years of underground coal mining does affect forced vital capacity (FVC), which in turn impairs exercise capacity, even in the absence of PMF. FVC should be the major spirometric value used in determining disability from CWP because it alone is seen to decrease in relation to mining, and a decrease in FVC does affect exercise capacity. Thus this analysis addresses issues in determining black lung disability and shows the value of casual modelling.     

Presence of acute phase response in coal workers' pneumoconiosis.

To evaluate the role of personal factors in pneumoconiosis, several acute phase proteins were studied in 62 coal miners without acute illnesses and classified as having no pneumoconiosis (n = 19), simple pneumoconiosis (n = 23), or complicated pneumoconiosis with progressive massive fibrosis (n = 20). Groups were similar for age, years of work at high risk jobs, chronic bronchitis, and forced expiratory volume in one second (FEV1). C-reactive protein concentration was significantly higher in the simple and complicated pneumoconiosis groups in comparison with the no pneumoconiosis group. The C-reactive protein concentration was above the upper normal value in 12 (27.9%) out of 43 cases with simple and complicated pneumoconiosis. On the other hand only one case of no pneumoconiosis was above the upper normal range (5.3%), a significant difference taking into account a stratified analysis for chronic bronchitis. Fibrinogen concentration was significantly increased in the simple pneumoconiosis group compared with the no pneumoconiosis group. The value of fibrinogen was above the upper normal limit in 17 out of the 43 cases with pneumoconiosis (39.5%) by contrast with two cases in the no pneumoconiosis group (10.5%). No significant differences in alpha 1-antitrypsin and ceruloplasmin concentrations were found between groups. In conclusion, an alteration in some acute phase proteins related to pneumoconiosis was found in miners. This could be used as a marker of disease activity and personal response against the pathogenic agent.     

Presence of acute phase response in coal workers' pneumoconiosis.

To evaluate the role of personal factors in pneumoconiosis, several acute phase proteins were studied in 62 coal miners without acute illnesses and classified as having no pneumoconiosis (n = 19), simple pneumoconiosis (n = 23), or complicated pneumoconiosis with progressive massive fibrosis (n = 20). Groups were similar for age, years of work at high risk jobs, chronic bronchitis, and forced expiratory volume in one second (FEV1). C-reactive protein concentration was significantly higher in the simple and complicated pneumoconiosis groups in comparison with the no pneumoconiosis group. The C-reactive protein concentration was above the upper normal value in 12 (27.9%) out of 43 cases with simple and complicated pneumoconiosis. On the other hand only one case of no pneumoconiosis was above the upper normal range (5.3%), a significant difference taking into account a stratified analysis for chronic bronchitis. Fibrinogen concentration was significantly increased in the simple pneumoconiosis group compared with the no pneumoconiosis group. The value of fibrinogen was above the upper normal limit in 17 out of the 43 cases with pneumoconiosis (39.5%) by contrast with two cases in the no pneumoconiosis group (10.5%). No significant differences in alpha 1-antitrypsin and ceruloplasmin concentrations were found between groups. In conclusion, an alteration in some acute phase proteins related to pneumoconiosis was found in miners. This could be used as a marker of disease activity and personal response against the pathogenic agent.     

Basic mechanisms leading to focal emphysema in coal workers' pneumoconiosis

Coal miners develop focal emphysema characterized by dilatation of second- and third-order respiratory bronchioles with coal mine dust-laden macrophages infiltrating the wall. A reticulin network with small amounts of collagen and atrophy of smooth muscle occurs. To evaluate the mechanisms of lung injury associated with this lesion, 17 long-term non- or ex-smoking West Virginia underground coal miners underwent bronchoalveolar lavage (BAL) and were compared to healthy nonsmoker and smoker controls. The coal miners had evidence of an alveolar macrophage-neutrophil alveolitis with a significant increase in neutrophils/microliter of epithelial lining fluid and an increased gallium lung scan index (206 +/- 26 units). Alveolar macrophages lavaged from coal miners spontaneously released exaggerated amounts of superoxide anion and hydrogen peroxide in vitro compared to nonsmoking controls. Coal workers had significantly elevated levels of neutrophil elastase in BAL fluid complexed with alpha 1-antitrypsin (P less than 0.01) and normal levels of alpha 1-antitrypsin. An accumulation of activated, dust-laden inflammatory cells with increased release of oxidants and elastase may contribute to the development of focal emphysema identified at postmortem in miners with coal workers' pneumoconiosis.     

Continued increase in lung transplantation for coal workers’ pneumoconiosis in the United States

Background

Severe coal workers’ pneumoconiosis (CWP) is increasingly common, and sometimes requires lung transplantation.

Methods

Using Organ Procurement and Transplantation Network data, we updated the trend for CWP‐related lung transplants, described CWP patients who have been waitlisted but not transplanted, and characterized the primary payer of medical costs for CWP‐related and other occupational lung disease transplants.

Results

There have been at least 62 CWP‐related lung transplants; 49 (79%) occurred in the last decade. The rate of these procedures has also increased. Twenty‐seven patients were waitlisted but did not receive a transplant. Compared to other occupational lung diseases, transplants for CWP were more likely to be paid for by public insurance.

Conclusions

The increase in the frequency and rate of lung transplantation for CWP is consistent with the rising prevalence of severe CWP among U.S. coal miners. Effective exposure controls and identification of early stage CWP remain essential for protecting these workers.