Early radiographic pneumoconiosis is associated with impaired exercise gas exchange among coal miners with normal resting spirometry.

RATIONALE: We sought to determine if radiographic pneumoconiosis predicts abnormal gas exchange during exercise in coal mine workers with preserved resting lung function. METHODS: We analyzed data from former coal miners seen between 2006 and 2014 in a single clinic specializing in black lung evaluations. We limited the analysis to those with normal resting spirometry and an A-a gradient at peak exercise ≥10 mmHg. We used multivariable logistic regression to estimate predictors of A-a gradient widened to >150% of the reference value. We focused on chest radiographs consistent with pneumoconiosis, taking into account higher silica exposure mining activities and years underground, and adjusting for cigarette smoking, obesity, and coronary artery disease. RESULTS: Of 5507 miners, we analyzed data for 742 subjects with normal spirometry and all key clinical variables available, of whom 372 (50.1%) had radiographic evidence of pneumoconiosis. All but 21 had small opacity profusion of less than 2/1. The median A-a gradient at peak exercise was 108% of reference value (interquartile range, 81%-141%). In the multivariable analysis, radiographic pneumoconiosis was associated with increased odds of widened A-a gradient (odds ratio [OR], 2.47; 95% confidence interval [CI], 1.7-3.7). Limited to 660 subjects with normal diffusing capacity for carbon monoxide, the odds were similarly increased (OR, 3.20; 95% CI, 1.5-3.6). DISCUSSION: Among coal miners with preserved resting lung function, radiographic evidence of early pneumoconiosis more than doubled the odds of abnormal exercise physiology. Impairment in pneumoconiosis occurs in early disease and may only be evident on exercise testing.

Respiratory traits and coal workers' pneumoconiosis: Mendelian randomisation and association analysis.

OBJECTIVES: Susceptibility loci of idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease were also significantly associated with the predisposition of coal worker's pneumoconiosis (CWP) in recent studies. However, only a few genes and loci were targeted in previous studies. METHODS: To systematically evaluate the genetic associations between CWP and other respiratory traits, we reviewed the reported genome-wide association study loci of five respiratory traits and then conducted a Mendelian randomisation study and a two-stage genetic association study. RESULTS: Interestingly, we found that for each SD unit, higher lung function was associated with a 66% lower risk of CWP (OR=0.34, 95% CI: 0.15 to 0.77, p=0.010) using conventional Mendelian randomisation analysis (inverse variance weighted method). Moreover, we found susceptibility loci of interstitial lung disease (rs2609255, OR=1.29, p=1.61×10-4) and lung function (rs4651005, OR=1.39, p=1.62×10-3; rs985256, OR=0.73, p=8.24×10-4 and rs6539952, OR=1.28, p=4.32×10-4) were also significantly associated with the risk of CWP. Functional annotation showed these variants were significantly associated with the expression of FAM13A (rs2609255, p=7.4 ×10-4), ANGPTL1 (rs4651005, p=5.4 ×10-7), SPATS2L (rs985256, p=1.1 ×10-5) and RP11-463O9.9 (rs6539952, p=7.1 ×10-6) in normal lung tissues, which were related to autophagy pathway simultaneously according to enrichment analysis. CONCLUSIONS: These results provided a deeper understanding of the genetic predisposition basis of CWP.

Medicare Claims Paid by the Federal Black Lung Benefits Program: US Medicare Beneficiaries, 1999 to 2016.

OBJECTIVE: To establish the burden of totally disabling respiratory impairment among coal miners, we identified the healthcare utilization and cost for Medicare claims where the Federal Black Lung Program (FBLP) was the primary payer. METHODS: We extracted FBLP claims from 1999 to 2016 institutional Medicare data along with beneficiary, comorbidity, and claim cost information. Healthcare utilization was evaluated and compared to the 2016 Medicare population. RESULTS: The FBLP was the primary payer on 75,690 claims from 19,700 beneficiaries and paid an increasing percentage of the total paid to providers annually. Claims decreased from 1999 to 2016 but cost per claim increased. Beneficiaries were hospitalized and visited the ER for respiratory and cardiovascular conditions. CONCLUSIONS: Medicare beneficiaries with FBLP primary payer claims have higher healthcare utilization and comorbidities compared with Medicare enrollees, indicative of increased financial and healthcare burden.

Assessment of subclinical right ventricular systolic dysfunction in coal miners using myocardial isovolumic acceleration.

OBJECTIVE: Several studies have been conducted regarding the effects of coal mining on the respiratory system. However, there is a lack of data concerning potential effects of coal mining on the cardiovascular system. In this study, we aimed to evaluate the potential subclinical right and left ventricular dysfunction in coal miners. METHODS: This single-center, prospective study included a total of 102 patients. Patient and control groups consisted of 54 coal miners and 48 healthy men, respectively. All patients underwent 12-lead electrocardiography, transthoracic echocardiography, and pulmonary function test. RESULTS: As compared to control group, coal miners had significantly higher right ventricular myocardial performance index (RVMPI) (0.41 ± 0.03 vs 0.37 ± 0.02, P < .001), lower right ventricular fractional area change (RVFAC) (33.55% ± 6.70% vs 37.04 ± 9.26 P < .05), lower tricuspid annular plane systolic excursion (TAPSE) (1.54 ± 0.17 vs 1.73 ± 0.25, P < .001), lower myocardial isovolumic acceleration (IVA) (2.13 ± 0.16 vs 2.56 ± 0.36 P < .001) and decreased aortic distensibility (AD) (4.14 ± 2.18 vs 6.63 ± 3.91 P < .001). All of the echocardiographic parameters were positively correlated with exposure time to coal mine dust, except IVA. CONCLUSION: Echocardiographic parameters of both right and left ventricular dysfunction, including RVMPI, RVFAC, TAPSE, IVA, and AD, are impaired in coal miners.

Increasing Severity of Pneumoconiosis Among Younger Former US Coal Miners Working Exclusively Under Modern Dust-Control Regulations.

BACKGROUND: Coal workers' pneumoconiosis (CWP) steadily declined among US miners following dust control regulations in 1970. In 2000, severe forms of this disease reemerged among young miners, and are well described among working-but not former-miners. METHODS: Black lung benefits program (BLBP) data (2001 to 2013) were used to estimate respiratory disease burden among former miners including: (1) CWP (simple; advanced CWP, and progressive massive fibrosis [CWP/PMF]); and (2) respiratory impairment (FEV1 percent reference: mild, moderate, ≥moderately-severe). RESULTS: Among 24,686 claimants, 8.5% had advanced CWP/PMF; prevalence was highest among younger (less than or equal to 56 years: 10.8%) and older (greater than 70 years: 8.4%) miners and those who began work after versus before 1970 (8.3% vs. 4.0%). CONCLUSIONS: BLBP claims provide potentially useful data for monitoring the burden and severity of coal mine dust lung disease, and assessing efficacy of protective regulations.

Cross-section analysis of coal workers' pneumoconiosis and higher brachial-ankle pulse wave velocity within Kailuan study.

BACKGROUND: Brachial-ankle pulse wave velocity (baPWV) is an independent predictor of cardiovascular events and mortality. However, there is no related data on the association of baPWVwith coal workers' pneumoconiosis (CWP). We explored the baPWV in subjects withCWP and the associated risk factors. METHODS: Thiscase-control study included 1,007 male CWP cases without a history of stroke and coronary heart disease and 1,007 matched controls from the Kailuan cohort study. All of the participants underwent assessment for baPWV and traditional cardiovascular risk factors. The cumulative silica dust exposure (work history linked to a job-exposure matrix) was estimated for the CWP cases. RESULTS: Compared with the controls, the CWP cases had higher baPWV (1762.0 ± 355 cm/s vs. 1718.6 ± 354 cm/s, P = 0.006) and a higher risk of increased baPWV (defined as more than the median baPWV of the population distribution; odds ratio 1.43, 95% confidence interval 1.11-1.83) after adjusting for traditional cardiovascular risk factors. Age ≥60 years, body mass index, heart rate, and hypertension were all significantly associated with increased baPWV in the CWP cases. Compared to non-CWP subjects without hypertension, the odds ratios for increased baPWV gradually increased (P for trend, 0.001) across the CWP subjects without hypertension (odds ratio 1.20, 95%confidence interval 0.90-1.61), subjects with hypertension alone (odds ratio 2.54, 95% confidence interval 1.95-3.30), and CWP subjects with hypertension (odds ratio 3.34, 95% confidence interval 2.56-4.37). We detected a significant positive exposure-response relationship between silica dust-exposure quartiles and increased baPWV in CWP cases (P for trend < 0.001). CONCLUSIONS: For patients with CWP, increased baPWV was associated with traditional cardiovascular risk factors and long-term silica dust exposure.

Ocular findings in coal miners diagnosed with pneumoconiosis.

OBJECTIVE: Our study aimed at evaluating ocular findings and structural changes in coal mine workers who were chronically exposed to coal mine dust and diagnosed with pneumoconiosis. METHODS: Ocular findings of 161 eyes of 81 patients diagnosed with pneumoconiosis who had previously worked or are currently working in coal mines were analyzed. Forty-six coal mine workers and sex matched healthy people (n = 20) participated in the study. Workers who had early changes of pneumoconiosis were included in Group 1 (n = 17), workers diagnosed with pneumoconiosis were included in Group 2 (n = 29), and healthy subjects were included in Group 3 (n = 20). Outcome measures were the difference in peripapillary retinal nerve fiber layer (RNFL) thickness, choroidal thickness (CT), central macular thickness (CMT) and tear function tests between the groups. RESULTS: RNFL thickness values in Group 1 and 2 were lower than in Group 3, the control group, in all quadrants except the temporal quadrant. However, there was no statistically significant difference in peripapillary RNFL thickness values in any quadrants among the three groups (p > 0.05). Central subfoveal choroidal thickness and CMT measurements were thinner in Group 1 and 2 than in the control group. However, this difference among groups was not statistically significant (p > 0.05). Mean schirmer's test result was 8.8 ± 1.6 mm in group 1, 7.1 ± 1.8 mm in Group 2 and 11.5 ± 3.6 mm in the control group. Mean tear break up time (BUT) test result was 7.1 ± 1.3 seconds (sec) in Group 1, 6.5 ± 1.8 sec in Group 2 and 10.4 ± 2.9 s in the control group. The Schirmer's test and BUT test results were both statistically significantly lower in coal mine workers (Group 1 and 2) compared to the control group. Group 1 and Group 2 did not show statistically significant difference in terms of Schirmer's test and BUT test results. DISCUSSION: The association between pneumoconiosis and coal mine dust contiguity is thought to be due to the effect of coal dust by producing chronic inflammation. In addition, there are several trace elements in coal dust which are toxic to vital tissues. In this study, ocular findings suggest that systemic levels of trace elements and chronic inflammation may not reach to a level that influences ocular structures. Nonetheless, tear functions seem to be affected in coal mine workers. CONCLUSION: This study suggests that the systemic effect of coal mine dust in ocular structures is not evident. However, direct contact with coal mine and fume leads to a decrease in tear function tests.

Emphysema and Airflow Obstruction in Non-Smoking Coal Miners with Pneumoconiosis.

BACKGROUND Accumulating evidence shows that functional impairment in subjects with coal workers' pneumoconiosis (CWP) is principally due to emphysema and airflow obstruction, rather than underlying restrictive mechanisms. However, cigarette smoking has remained a major confounder. The aim of this study was to assess whether coal dust exposure was associated with emphysema and/or airflow obstruction in the absence of smoking history. MATERIAL AND METHODS The subjects evaluated for possible pneumoconiosis between 2013 and 2015 were retrospectively enrolled into this study. After excluding those with history of smoking, tuberculosis, or lung cancer, the study population was a total of 57 subjects. The emphysema severity and airflow obstruction were quantified by computed tomographic densitometry analysis and spirometry, respectively. For comparability regarding emphysema, 9 age- and sex-matched nonsmoker (n=9) control subjects without known lung disease were randomly selected from a radiology database. RESULTS Emphysema severity was significantly higher in the CWP group compared with the control group (15% vs. 4%, p<0.001). The median percent emphysema and percentage of those with FEV1/FVC <0.7 was 13% and 37% in subjects with simple CWP and 18% and 67% in subjects with complicated CWP, respectively. Percent emphysema and Perc15 (15th percentile of the attenuation curve) was correlated with FEV1/FVC (r=-0.45, r=-0.47) and FEF25-75 (r=-0.36, r=-0.56), respectively, but not with perfusion score. A linear regression analysis showed that factors associated with emphysema were FEV1/FVC (ß=-0.24, p=0.009) and large opacity (ß=-3.97, p=0.079), and factors associated with FEV1/FVC were percent emphysema (ß=-0.51, p=0.018) and tenure (ß=-0.63, p=0.044). CONCLUSIONS Our results support the observation that coal dust exposure is associated with emphysema and airflow obstruction, independent of smoking status.

Relationship of cumulative dust exposure dose and cumulative abnormal rate of pulmonary function in coal mixture workers.

To investigate the dose-response relationship between cumulative dust exposure (CDE) and cumulative abnormal rate of pulmonary function in coal mixture workers. Three hundred and twenty eight coal mixture workers (exposed group) and 169 nondust-exposed workers (control group) were recruited. Basic information data were collected and pulmonary function tests were performed. Pulmonary function was compared between the two groups after comparing smoking behaviors. Pulmonary function indices [forced vital capacity in 1 second after full inspiration (FVC)%, forced expiratory volume (FEV)1%, and FEV1/FVC%] were compared among groups stratified by service length (exposure duration). The relationship between CDE dose and cumulative abnormal rate of pulmonary function in coal mixture workers was analyzed. Abnormal rate of pulmonary function in the exposed group (35.1%) was significantly higher than the control group (10.1%; p < 0.001); FVC%, FEV1%, and FEV1/FVC% in the exposed group decreased significantly compared with the control group (all p < 0.05). Differences in FVC%, FEV1%, and FEV1/FVC% among coal mixture workers stratified by exposure duration in the exposed group were statistically significant (all p < 0.05). The discernible increase in the cumulative abnormal rate was observed, from ≥ 1000 mg/m(3)·years group to ≥ 1700 mg/m(3)·years group. Correlation analysis revealed a positive correlation between the CDE dose and the cumulative abnormal rate of pulmonary function. Higher abnormal pulmonary function rate was found among coal mixture workers, characterized by decreased pulmonary function indices. Our results suggested a positive relationship between CDE dose and cumulative abnormal pulmonary function rate, and a rapid increase in cumulative abnormal rate within a certain range of CDE dose. A lower limit value of 1000 mg/m(3)·years has reference significance.

Lung transplantation is increasingly common among patients with coal workers' pneumoconiosis.

BACKGROUND: The prevalence of coal workers' pneumoconiosis (CWP) in U.S. coal miners has increased, and severe presentations are increasingly common. METHODS: We describe trends in lung transplantation during 1996-2014 for recipients with a primary diagnosis of CWP or pneumoconiosis unspecified, and we summarize recipient characteristics and estimate survival. RESULTS: A total of 47 transplants were included; nearly three-quarters were performed during 2008-2014. All recipients were male, 96% were white, and the mean age was 56 years. Mean FEV1 % was 35%; mean FVC% was 53%. Mean time on a waitlist was 155 days, and 60% of transplants were bilateral. Median survival was 3.7 years. CONCLUSIONS: These transplants reflect the use of a scarce resource for an entirely preventable disease, and highlight the need for enhanced efforts to reduce coal mine dust exposures.

Prevalence Characteristics of Coal Workers' Pneumoconiosis (CWP) in a State-Owned Mine in Eastern China.

Coal Workers' Pneumoconiosis (CWP) is the primary occupational disease in China. However, information about the definite prevalence of CWP is only partially available. The aims of our study were to assess the prevalence characteristics of CWP in a state-owned coal mine, evaluate the effects of control measures and develop further preventive strategies for CWP. The total study population included 495 cases who were diagnosed with CWP from the construction of this coal mine to the end of October 2014. Individuals' information, including duration of dust exposure, job titles, age as first diagnosis, stages of CWP, CWP progress, complications with pulmonary tuberculosis, death and others were collected and analyzed. The results showed that 71.11% of 495 CWP cases were stage I and 90.71% were involved in tunneling or coal mining. The mean dust exposure period in CWP patients was 26.7 years, the mean latent period was 29.3 years and the mean diagnosed age was 50.3 years old. The proportion of CWP diagnosed after ending dust exposure were remarkably increased with the time passing. Among the CWP cases, 36 (7.27%) were complicated with pulmonary tuberculosis. The mortality of patients with stage III was the highest (60.71%) (p < 0.0001). Our data obviously show that more strict policies to protect coal miners are needed to be implemented in China, especially for tunneling and mining workers.

Impairment of pulmonary function and changes in the right cardiac structure of pneumoconiotic coal workers in China.

INTRODUCTION: Information on the changes of pulmonary function and the right cardiac structure in patients with coal worker's pneumoconiosis in China is very scarce. This study was performed to clarify the changes of pulmonary function and right cardiac structure in patients with coal worker's pneumoconiosis in China. MATERIAL AND METHODS: Pulmonary function, pulmonary artery systolic pressure, and the right cardiac structure were evaluated by spirometry and color Doppler echocardiography. RESULTS: The pulmonary artery systolic pressure of patients with coal worker's pneumoconiosis was increased with disease severity. Patients with coal worker's pneumoconiosis also exhibited an impaired pulmonary function and altered right cardiac structure compared with control subjects. A significant linear correlation of the variables of pulmonary ventilation and diffusion function with the indicators of the right cardiac structure was found in patients with coal worker's pneumoconiosis in China. CONCLUSIONS: This study elucidated a deterioration of pulmonary function and right cardiac structure in patients with coal worker's pneumoconiosis in China.

Profusion of Opacities in Simple Coal Worker's Pneumoconiosis Is Associated With Reduced Lung Function.

BACKGROUND: A large body of evidence demonstrates dose-response relationships of cumulative coal mine dust exposure with lung function impairment and with small-opacity profusion. However, medical literature generally holds that simple coal worker's pneumoconiosis (CWP) is not associated with lung function impairment. This study examines the relationship between small-opacity profusion and lung function in US underground coal miners with simple CWP. METHODS: Miners were examined during 2005 to 2013 as part of the Enhanced Coal Workers' Health Surveillance Program. Work histories were obtained, and chest radiographs and spirometry were administered. Lung parenchymal abnormalities consistent with CWP were classified according to International Labor Organization guidelines, and reference values for FEV1 and FVC were calculated using reference equations derived from the third National Health and Nutrition Examination Survey. Differences in lung function were evaluated by opacity profusion, and regression models were fit to characterize associations between profusion and lung function. RESULTS: A total of 8,230 miners were eligible for analysis; 269 had category 1 or 2 simple CWP. Decrements in FEV1 % predicted were nearly consistent across profusion subcategories. Clear decrements in FVC % predicted and FEV1/FVC were also observed, although these were less consistent. Controlling for smoking status, BMI, and mining tenure, each 1-unit subcategory increase in profusion was associated with decreases of 1.5% (95% CI, 1.0%-1.9%), 1.0% (95% CI, 0.6%-1.3%), and 0.6% (95% CI, 0.4%-0.8%) in FEV1 % predicted, FVC % predicted, and FEV1/FVC, respectively. CONCLUSIONS: We observed progressively lower lung function across the range of small-opacity profusion. These findings address a long-standing question in occupational medicine and point to the importance of medical surveillance and respiratory disease prevention in this workforce.

Small airways involvement in coal mine dust lung disease.

Inhalation of coal mine dust results in a spectrum of symptoms, dysfunction, and pathological changes in the respiratory tract that collectively have been labeled coal mine dust lung disease. Recent reports from periodic health surveillance among underground and surface coal miners in the United States have demonstrated an increasing prevalence and severity of dust diseases, and have also documented that some miners experience rapid disease progression. The coal macule is an inflammatory lesion associated with deposited dust, and occurs in the region of the most distal conducting airways and proximal respiratory bronchioles. Inflammatory changes in the small airways have long been recognized as the signature lung pathology among coal miners. Human and laboratory studies have suggested oxidant injury, and increased recruitment and activity of macrophages play important roles in dust-induced lung injury. However, the functional importance of the small airway changes was debated for many years. We reviewed published literature that documents a pervasive occurrence of both physiologic and structural abnormalities in small airways among coal miners and other workers exposed to airborne particulates. There is increasing evidence supporting an important association of abnormalities in the small peripheral airways with the development of respiratory symptoms, deficits in spirometry values, and accelerated declines in ventilatory lung function. Pathologic changes associated with mineral dust deposition in the small airways may be of particular importance in contemporary miners with rapidly progressive respiratory impairment.

[The effect of pneumoconiosis observation object and coal workers' pneumoconiosis in one stage again in the dust exposure work after whole lung lavage].

OBJECTIVE: To investigate the effects of secondary dust exposure after whole-lung lavage (WLL) on the clinical symptoms, arterial blood gas parameters, and pulmonary function in subjects with pneumoconiosis and patients with stage I coal workers' pneumoconiosis (CWP). METHODS: The subjects with pneumoconiosis and patients with stage I CWP who underwent WLL in our hospital during the study period were selected. All patients were divided into postoperative dust exposure group (n = 86) and lavage control group (n = 86) according to whether they were exposed to dust after conventional operation. In addition, their workmates with similar age, history of dust exposure, and type of dust exposure were selected as non-lavage control group (n = 86). Follow-up was performed before and at one month and one year after WLL to evaluate clinical symptoms, arterial blood gas parameters, and pulmonary function. RESULTS: One month after operation, the clinical scores of the postoperative dust-exposure group and lavage control group were significantly reduced compared with their preoperative scores and the clinical score of the non-lavage control group (P < 0.01). One year after operation, the clinical scores of the postoperative dust-exposure group and lavage control group were significantly reduced compared with their preoperative scores and the clinical score of the non?lavage control group (P < 0.01), and the lavage control group had a significantly lower clinical score than the postoperative dust exposure group (P < 0.01). One month after operation, the arterial partial pressure of oxygen (PaO2) of the postoperative dust-exposure group and lavage control group were significantly higher than their preoperative values and the arterial PaO2 of the non-lavage control group (P < 0.01). One year after operation, the lavage control group had significantly higher arterial PaO2 than the postoperative dust exposure group and the arterial PaO2 of the non-lavage control group was significantly lower than its preoperative value and the arterial PaO2 of the postoperative dust exposure group and lavage control group (P < 0.05 or P < 0.01); the postoperative dust exposure group showed a significant decrease in arterial PaO2 (P < 0.01), while the lavage control group showed a significant increase in arterial PaO2 (P < 0.01). The partial pressure of carbon dioxide showed no significant differences between the three groups before and at one month and one year after operation (P > 0.05). CONCLUSION: Dust exposure should be avoided after WLL to ensure the treatment outcome.

[Ventilatory function in patients with silicosis or coal workers' pneumoconiosis]. / Výskyt ventilacní poruchy plic u osob se silikózou a pneumokoniózou uhlokopa.

OBJECTIVES: The aim of the study was to determine ventilatory function in a group of patients with silicosis and coal workers pneumoconisos (CWP) newly granted as occupational disease. METHODS: The authors have undertaken the analysis of all cases of occupational silicosis and CWP which were diagnosed in men in the South Moravia region. Information on ventilatory function, chest symptoms, age, working and smoking history was collected during the medical surveys, including spirometry testing and chest radiography. Diagnosis was based on history of occupational exposure to coal or silica dust, chest x-ray findings, using International Labour Office classification. RESULTS: In the years 1997-2014, 116 occupational silicosis and coal workers´ pneumoconiosis have been notified. There were diagnosed 42 cases of simple and 17 cases of complicated silicosis, 40 cases of the simple and 17 cases of complicated CWP. Duration of exposure to respiratory hazards, smoking history and prevalence of ventilatory impairment were not significantly different between these groups. The mean age of persons at diagnosing occupational disease was 61.0 (SD 11.2) years, the mean duration of exposure to respirable dust was 24.7 (SD 10.2) years. Abnormal spirometry results were detected in 51.7% of pneumoconiotics--8.6% with restrictive, 11.2% with obstructive, and 31.9 with mixed impairment. The prevalence of ventilatory function impairment was found to be significantly associated with chronic obstructive pulmonary disease and age. CONCLUSIONS: Testing of ventilatory function has an important role in the evaluation of lung disease in employees exposed to various respirable hazards. Although such testing was not useful for diagnosing silicosis or CWP, it was important for evaluating compensation amount for occupational disease in 51.7% pneumoconiotic patiens.

Serum levels of TGF-ß1 and MCP-1 as biomarkers for progressive coal workers' pneumoconiosis in retired coal workers: a three-year follow-up study.

Various cytokines activated by the inhalation of coal dust may mediate inflammation and lead to tissue damage. Objective of this study was to examine the relationships between coal workers' pneumoconiosis (CWP) progression over a 3 yr period and the serum levels of cytokines in 85 retired coal workers. To investigate the relevance of serum cytokines in CWP, serum levels of interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta1 (TGF-ß1), and monocyte chemotactic protein-1 (MCP-1) as progressive CWP biomarkers were studied in relation to the progression of pneumoconiosis over a 3 yr period in 85 patients with CWP. CWP progression was evaluated through paired comparisons of chest radiographs. Median levels of TGF-ß1 and MCP-1 were significantly higher in subjects with progressive CWP than in those without CWP progression. The area under the ROC curve for TGF-ß1 (0.693) and MCP-1 (0.653) indicated that these cytokines could serve as biomarkers for the progression of CWP. Serum TGF-ß1 levels were related to the progression of CWP (ß=0.247, p=0.016). The results suggest that high serum levels of TGF-ß1 and MCP-1 are associated with the progression of CWP.

Rapid decline in lung function in coal miners: evidence of disease in small airways.

BACKGROUND: Coal mine dust exposure can cause both pneumoconiosis and chronic airflow limitation. The contributions of various pathophysiologic mechanisms to dust-related lung function decrements remain unclear. METHODS: Clinical and physiological findings were assessed for 15 underground coal miners who had demonstrated accelerated FEV1 losses (decliners) over 6-18 years. Decliners' findings were evaluated in comparison to a group of 11 miners who had shown relatively stable lung function (referents) during the same period. RESULTS: At follow-up examination, the decliners showed significantly greater mean airway resistance (10.47 vs. 6.78 cmH2 O/L/s; P = 0.05) and more air trapping (RV/TLC = 37.5 vs. 29.1%; P < 0.01) compared to the referents. Decliners also demonstrated more evidence of small airways dysfunction and tended to have more bronchospasm than the referent group. Total lung capacity, lung compliance, diffusing capacity, and chest radiography did not differ significantly between the two groups. After cessation of mine dust exposures, the decliners' mean rate of FEV1 loss normalized. CONCLUSION: In a series of working coal miners, accelerated lung function declines were associated with air trapping and evidence of small airways dysfunction. A preventive benefit from controlling dust exposures was suggested.