Cross sectional and longitudinal study on selenium, glutathione peroxidase, smoking, and occupational exposure in coal miners

OBJECTIVES—To understand the variations of selenium (Se) concentration relative to changes in occupational exposure to coal dust, taking into account age and changes in smoking habits in miners surveyed twice, in 1990 and 1994. To better understand the relation of Se concentration with glutathione peroxidase activities (GSH-Px) in these miners.
METHODS—In 1994, blood samples were obtained from active (n=131) and retired (n=40) miners without coal worker''s pneumoconiosis, in whom Se concentration was available at both surveys and in whom International Labour Organisation (ILO) profusion grade had not been changed. Active miners were exposed to high dust concentrations (n=48) or low dust concentrations (n=83). Miners were classified into three subgroups according to their estimated cumulative exposure to dust, and into three subgroups according to their smoking habits.
RESULTS—Selenium concentration and GSH-Px activities were significantly lower in active than in retired miners (Se adjusted means: 62.6 v 72.2 ng/ml p=0.01). Moreover, Se concentration was lower in miners exposed to high compared with those exposed to low dust concentrations (adjusted means: 59.4 v 65.8). In miners exposed to high dust concentrations, Se concentration was significantly lower whereas erythrocyte GSH-Px activity was significantly higher in the subgroup with estimated cumulative exposure >68 mg/m³.y. In all miners, plasma GSH-Px activity was correlated with Se concentration (r=0.22, p<0.005). The 4 year Se changes were negatively related to exposure to high dust concentrations and positively related to change in exposure from high to retirement and to change from smoker to ex-smoker (p=0.01).
CONCLUSION—The variations of Se concentration in relation to changes in occupational exposure to coal dust and in smoking habits, and the close correlation found between plasma Se concentration and GSH-Px activity suggest that both are required in antioxidant defence. These results agree well with the hypothesis that the decrease in Se concentration reflects its use against reactive oxygen species generated by exposure to coal mine dust and by smoking.


     

Epidemiological evaluation of release of monocyte TNF-alpha as an exposure and effect marker in pneumoconiosis: a five year follow up study of coal workers.

OBJECTIVES--To determine (a) reproducibility with previous cross sectional findings, and (b) the predictive value of initial release of tumour necrosis factor-alpha (TNF-alpha) towards later progression of coalworkers' pneumoconiosis (CWP). METHODS--Release of monocyte TNF-alpha after in vitro stimulation with coal mine dust, silica, and endotoxin was measured in 104 retired miners and was related to stage of CWP (chest radiograph) and cumulative exposure. A subgroup of 46 miners was screened by high resolution computed tomography (HRCT). Prospective analysis of TNF-alpha (40 out of 104 miners involved in the previous TNF-alpha study) was done by relating initial TNF-alpha to five year progression of CWP measured by comparison of paired chest radiographs. RESULTS--As observed previously, dust stimulated release of TNF-alpha was increased in miners, especially in the early stages of pneumoconiosis. Cumulative exposure was related to pneumoconiotic stage but not to release of TNF-alpha. This excluded TNF-alpha as an exposure marker. Initial concentrations (1987) of TNF-alpha were related to later progression of CWP. Miners who showed abnormally high dust stimulated release of TNF-alpha had an increased risk of progression in CWP (relative risk 8.1). CONCLUSIONS--These results show (a) the significant involvement of TNF-alpha in pneumoconiosis in humans induced by coal dust and (b) that this routine test possibly constitutes a powerful tool to estimate individual prognosis of pneumoconiotic disease, even after the end of occupational exposure.     

Blood antioxidant enzymes as markers of exposure or effect in coal miners.

OBJECTIVE--To investigate if blood Cu++/Zn++ superoxide dismutase, glutathione peroxidase, catalase, and total plasma antioxidant activities could be markers of biological activity resulting from exposure to respirable coal mine dust in active miners, and of pneumoconiosis in retired miners. METHODS--Blood samples were randomly obtained from active surface workers (n = 30) and underground miners (n = 34), and from retired miners without (n = 21), and with (n = 33) pneumoconiosis. Antioxidant enzyme activities and total plasma antioxidants were measured in erythrocytes and plasma. Non-parametric tests were completed by analyses of covariance to compare antioxidants between groups, taking into account potential confounding factors (age, smoking history (pack-years)). RESULTS--Erythrocyte Cu++/Zn++ superoxide dismutase activity was significantly higher in the group of underground miners than the group of surface workers. The differences in total plasma antioxidants and plasma glutathione peroxidase activity between both groups were related to age. Glutathione peroxidase activity increased in the plasma of retired miners with pneumoconiosis, compared with retired miners without pneumoconiosis. No differences were found either in erythrocyte antioxidant enzyme activities or in total plasma antioxidants between the groups of retired miners without and with pneumoconiosis. CONCLUSIONS--In this study, erythrocyte Cu++/Zn++ superoxide dismutase activity may be considered as a marker of effect of respirable coal mine dust in exposed workers. This result is in agreement with the hypothesis that reactive oxygen species are involved in cell injury induced by coal mine dust, and may be predictive of the degree of inflammation and pneumoconiosis induced by coal mine dust. The increase in glutathione peroxidase activity in the plasma of retired miners with pneumoconiosis may be the result of a response to the increasing hydrogen peroxide (H2O2) production due to the disease process.     

Prevalence of pneumoconiosis and its relationship to dust exposure in a cohort of U.S. Bituminous coal miners and ex-miners

Information on radiographic evidence of coal workers' pneumoconiosis (CWP) is presented for a group of 3,194 underground bituminous coal miners and ex-miners examined between 1985 and 1988. Prevalence of CWP was related to estimated cumulative dust exposure, age, and rank of coal. On the basis of these data, miners of medium to low rank coal, who work for 40 years at the current federal dust limit of 2 mg/m³, are predicted to have a 1.4% risk of having progressive massive fibrosis on retirement. Higher prevalences are predicted for less severe categories of CWP. Miners in high rank coal areas appear to be at greater risk than those mining medium and low rank coals. Ex-miners who said that they left mining for health-related reasons had higher levels of abnormality compared to current miners.     

Evaluation of serum type III procollagen peptide as an exposure marker in retired coal workers

Serum type III procollagen peptide (PIIIP), a degradation product of the type III collagen precursor, has been put forward as an exposure marker for mineral dust. We evaluated PIIIP levels as a marker of exposure to and effects of coal dust in retired coal miners (n = 104). To this end: (a) the individual cumulative dust exposure was calculated from job-exposure matrices, and (b) in addition to routine chest radiography (CR) of all miners according to the criteria of the International Labour Organisation (ILO), a subgroup (n = 46) was screened by high-resolution computed tomography (HRCT). Profusion score (CR and HRCT) tended to increase with cumulative dust exposure, even in the absence of CR evidence for pneumoconiosis (i.e. CR , 0/1, n = 35). In contrast to our previous findings in active miners, PIIIP levels were not increased in miners as compared with non-dust-exposed controls (n = 29), and no differences were observed between miners without (ILO = 0/0) and miners with coal workers' pneumoconiosis (CWP; ILO 0/1). No trend in PIIIP versus pneumoconiosis stage was present, either by CR or by the more sensitive HRCT score. PIIIP was also unrelated to any lung function parameter (FEV₁, FVC, impedance, diffusion capacity). Age, medication, medical history and smoking habits had no significant effect on PIIIP levels. In the miners with CWP (i.e. ILO > 0/0, n = 28) a significant negative correlation was present between PIIIP values and (log) cumulative dust exposure. This decrease in serum PIIIP levels with increasing cumulative exposure may be due to chronic adaptive changes in type III collagen deposition and/or breakdown. Other relations between exposure and PIIIP were not observed. In conclusion, the present findings do not support the use of serum type III procollagen peptide as a marker of exposure to and (early) interstitial or respiratory effects of coal dust.     

Antioxidant response at early stages and low grades of simple coal worker's pneumoconiosis diagnosed by high resolution computed tomography

In miners exposed to coal dusts, coal worker's pneumoconiosis (CWP) can occur. The purpose of the present study is to better understand the relations between coal dust exposure and activities of blood plasma antioxidant enzymes, namely, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and lipid peroxidation end product malondialdehyde (MDA) concentration in coal workers with early and low grade simple CWP diagnosed by high resolution computed tomography (HRCT). Forty-three coal workers who had profusions of 0/1-2/2 according to ILO 1980 chest X-ray (CXR) classification, 43 coal workers without CWP (control group 1) and 44 healthy subjects (control group 2) who were randomly selected from the population register or recruited from the hospital staff were enrolled. Coal workers were reevaluated by HRCT (Hosoda-Shida classification) due to its higher sensitivity than standard CXR. Then, blood plasma SOD and GSH-Px activities and MDA plasma levels were measured. CWP was found positive in 46 of 89 coal workers by HRCT evaluation. Profusion 0 (P0, CWP not present), profusion 1 (P1, early CWP) and profusion 2 (P2, low grade CWP) were found in 43, 23 and 19 of patients found to have CWP by HRCT, respectively. We had no worker with profusion 3 (P3). Complicated CWP was shown in four of 46 patients and thesecases were excluded as the study was restricted to early and low-grade pneumoconiosis. In respect to the plasma levels of MDA and plasma activities of SOD and GSH-Px, statistically significant differences were found between CWP cases and control groups (p < 0.01, p < 0.01, p < 0.001 respectively). Statistical differences were also obtained for the plasma activities of SOD and GSH-Px and levels of MDA in relation to HRCT profusions (p < 0.05). In conclusion, these findings suggest an oxidative stress due to increased free radicals and reactive oxygen metabolite production in early stages and low grades of simple CWP diagnosed by HRCT.     

Rapidly progressive coal workers' pneumoconiosis in the United States: geographic clustering and other factors

Background: Despite significant progress made in reducing dust exposures in underground coal miners in the United States, severe cases of coal workers'' pneumoconiosis (CWP), including progressive massive fibrosis (PMF), continue to occur among coal miners. Aims: To identify US miners with rapidly progressive CWP and to describe their geographic distribution and associated risk factors. Methods: Radiographic evidence of disease progression was evaluated for underground coal miners examined through US federal chest radiograph surveillance programmes from 1996 to 2002. A case of rapidly progressive CWP was defined as the development of PMF and/or an increase in small opacity profusion greater than one subcategory over five years. County based prevalences were derived for both CWP and rapidly progressive cases. Results: A total of 886 cases of CWP were identified among 29 521 miners examined from 1996 to 2002. Among the subset of 783 miners with CWP for whom progression could be evaluated, 277 (35.4%) were cases of rapidly progressive CWP, including 41 with PMF. Miners with rapidly progressive CWP were younger than miners without rapid progression, were more likely to have worked in smaller mines (<50 employees), and also reported longer mean tenure in jobs involving work at the face of the mine (in contrast to other underground mining jobs), but did not differ with respect to mean underground tenure. There was a clear tendency for the proportion of cases of rapidly progressive CWP to be higher in eastern Kentucky, and western Virginia. Conclusions: Cases of rapidly progressive CWP can be regarded as sentinel health events, indicating inadequate prevention measures in specific regions. Such events should prompt investigations to identify causal factors and initiate appropriate additional measures to prevent further disease.     

Erythrocyte antioxidant enzyme activities in coal miners from three French regions

This study investigated whether differences in the prevalence and severity of coal workers' pneumoconiosis (CWP) between three coal mines could be related to differences in oxidative stress exposure as evaluated in vivo through red-blood-cell antioxidant enzyme activities. Blood samples were obtained from 229 miners selected according to their occupation and their pneumoconiotic status. The following biomarkers were evaluated: erythrocyte catalase, Cu²⁺/Zn²⁺ superoxide dismutase (Cu²⁺/Zn²⁺ SOD), and glutathione peroxidase activities. Antioxidant enzyme activities did not differ significantly between the group of surface workers in Lorraine and the group of underground miners without CWP in Lorraine and in the other coal mines. Erythrocyte Cu²⁺/Zn²⁺ SOD activity was slightly decreased in the group of active underground miners with simple pneumoconiosis as compared with the group of miners without CWP in Nord/Pas-de-Calais. No effect was seen between retired miners at different stages of CWP. Our findings indicate that differences in the prevalence and severity of CWP do not seem to be related to various oxidative activities of coal dust particles, at least as reflected by measurements of antioxidant enzyme activities in circulating erythrocytes in this study. Received: 3 March 1997 / Accepted: 14 October 1997     

Gallium-67 citrate imaging in underground coal miners

Twenty-two underground coal workers with 27 or more years of coal dust exposure were studied with gallium-67 citrate (Ga-67) imaging. Radiographic evidence of coal workers pneumoconiosis (CWP) was present in 12 subjects. The Ga-67 scan was abnormal in 11 of 12 with, and 9 of 10 without, CWP. The Ga-67 uptake index was significantly correlated with total dust exposure (p less than 0.01) and approached significant correlation with the radiographic profusion of the nodules (0.10 greater than p greater than 0.05). There was no correlation between Ga-67 uptake and spirometric function, which was normal in this group of patients; furthermore, increased lung uptake of gallium did not indicate a poor prognosis in subjects no longer exposed to coal dust. While coal dust exposure may be associated with positive Ga-67 lung scan in coal miners with many years of coal dust exposure, the scan provided no information not already available from a careful exposure history and a chest radiograph. Since Ga-67 scanning is a relatively expensive procedure we would recommend that its use in subjects with asymptomatic CWP be limited to an investigative role and not be made part of a routine evaluation.     

An investigation into the relationship between coal workers' pneumoconiosis and dust exposure in U.S. coal miners.

The National Study of Coal Workers' Pneumoconiosis (NSCWP) is a large, continuing epidemiologic study of the respiratory health of U.S. coal miners. By using information from the study, prevalence of coal workers' pneumoconiosis (CWP) was related to indexes of dust exposure obtained from research and compliance sampling data. Clear relationships between prevalences of both simple CWP and progressive massive fibrosis (PMF) and estimated dust exposure were seen. Additional effects independently associated with coal rank (% carbon) and age were also seen. Logistic model fitting indicated that between 2% and 12% of miners exposed to a 2-mg/m3 dust environment in bituminous coal mines would be expected to have Category 2 or greater CWP after a 40-yr working life; PMF would be expected for between 1.3% and 6.7%. The risks for anthracite miners appeared to be greater. There was a suggestion of a background level of abnormality, not associated with dust exposure, but increasing with age. Although there are certain weaknesses in the data used to derive these exposure estimates, the results are in general agreement with, but somewhat greater than, some recent findings for British coal miners.     

CT和高分辨CT对煤工尘肺小阴影和阴影融合及肺气肿诊断的价值

目的 探讨CT和高分辨CT(HRCT)早期检测煤工尘肺小阴影、阴影融合与肺气肿的敏感性和准确性.方法 77例煤工尘肺患者、36例无尘肺煤工和37例健康非煤工接受多层螺旋CT机无间隔胸部容积扫描及HRCT扫描,对所获得的CT图像进行煤工尘肺小阴影密集度分级、平均肺密度值和肺气肿指数测定,并与其X线胸片诊断结果对照.结果 对77例煤工尘肺患者CT和HRCT诊断的尘肺小阴影密集度分级与X线胸片尘肺分期一致性较好(Kappa=0.771,P＜0.01).CT和HRCT诊断尘肺的敏感性达到98.70％,在X线胸片确诊的77例煤工尘肺患者中,CT和HRCT评估76例为煤工尘肺,可疑1例.CT和HRCT从36例X线胸片无尘肺煤工中检出8例(22.22％)达到小阴影密集度1级;从73例Ⅰ～Ⅱ期煤工尘肺患者中,检出26例(35.62％)阴影密集度≥3级,其中3级密集度阴影20例,4级密集度阴影6例;对4例X线胸片Ⅲ期煤工尘肺患者,CT和HRCT与X线胸片诊断结果相同.从113例煤工中,X线胸片检出肺气肿7例(6.19％),CT检出36例(31.86％).CT尘肺小阴影密集度1～2级组的CT平均肺密度值最高,明显高于健康对照组、无尘肺组和小阴影密集度4级组,差异有统计学意义(F1=-45.73、F2=-23.00和F3=57.72,P＜0.01或P＜0.05).结论 从多层螺旋CT获得的CT和HRCT影像,与X线胸片比较,对煤工尘肺小阴影、阴影融合与肺气肿识别的敏感性和准确性均较高,可为煤工尘肺及其并发症的早期诊断提供更先进的手段.     

Pneumoconiosis and advanced occupational lung disease among surface coal miners--16 states, 2010-2011

Coal workers' pneumoconiosis (CWP) is a chronic occupational lung disease caused by long-term inhalation of dust, which triggers inflammation of the alveoli, eventually resulting in irreversible lung damage. CWP ranges in severity from simple to advanced; the most severe form is progressive massive fibrosis (PMF). Advanced CWP is debilitating and often fatal. To prevent CWP, the Coal Mine Health and Safety Act of 1969 established the current federal exposure limit for respirable dust in underground and surface coal mines. The Act also established a surveillance system for assessing prevalence of pneumoconiosis among underground coal miners, but this surveillance does not extend to surface coal miners. With enforcement of the exposure limit, the prevalence of CWP among underground coal miners declined from 11.2% during 1970-1974 to 2.0% during 1995-1999, before increasing unexpectedly in the last decade, particularly in Central Appalachia. Exposure to respirable dust is thought to be less in surface than underground coal miners. Although they comprise 48% of the coal mining workforce, surface coal miners have not been studied since 2002. To assess the prevalence, severity, and geographic distribution of pneumoconiosis among current surface coal miners, CDC obtained chest radiographs of 2,328 miners during 2010-2011 through the Coal Workers' Health Surveillance Program of the National Institute for Occupational Safety and Health (NIOSH). Forty-six (2.0%) of 2,257 miners with >1 year of surface mining experience had CWP, including 37 who had never worked underground. Twelve (0.5%) had PMF, including nine who had never worked underground. A high proportion of the radiographs suggested silicosis, a disease caused by inhalation of crystalline silica. Surface coal mine operators should monitor worker exposures closely to ensure that both respirable dust and silica are below recommended levels to prevent CWP. Clinicians should be aware of the risk for advanced pneumoconiosis among surface coal miners, in addition to underground coal miners, to facilitate prompt disease identification and intervention.     

Presence of stable coal radicals in autopsied coal miners' lungs and its possible correlation to coal workers' pneumoconiosis.

Stable coal radicals (SCRs) were detected by electron spin resonance (ESR) spectroscopy in the lung tissue of autopsied coal miners. The SCR concentrations were measured in the lung tissues from 98 coal miners with and without (a) coal workers' pneumoconiosis (CWP), (b) cancer, and (c) a history of cigarette smoking. Concentrations of SCRs were also determined in the lungs of nonminer controls. The SCR concentration was related to longer mining tenure, CWP disease severity, lung cancer, and cigarette smoking. The mean concentration of SCRs in the lung tissues of miners with 30 +/- 1.4 y of coal mining exposure was 5.3 +/- 1.3 x 10(17) spins/g versus controls who had a nondetectable level (less than 10(15) spins/g). An increase in disease severity was accompanied by a progressive increase in SCR concentration. A SCR concentration of 4.8 +/- 0.7 x 10(17) spins/g was found for simple CWP (with moderate coal macules) versus 7.8 +/- 4.6 spins/g lung tissue for complicated CWP (with progressive massive fibrosis). Significantly higher (i.e., 10 x 10(17] concentrations of SCR in the coal miners' lung tissues were associated with an exposure history in the anthracite regions of northeastern Pennsylvania. These results indicate a possible role for SCRs in the disease process. Furthermore, ESR appears to be an adequate methodology for the quantitation of coal dust retained in the lung and for distinguishing exposures to anthracite and/or bituminous coal.     

Genetic polymorphisms of MnSOD, GSTM1, GSTT1, and OGG1 in coal workers' pneumoconiosis

Little is known about the genetic susceptibility to coal workers' pneumoconiosis (CWP). We investigated the association between genetic polymorphisms of MnSOD, GSTM1, GSTT1, or OGG1 and susceptibility to CWP. The study population was composed of 259 Chinese retired coal miners who had similar dust exposure histories. Of these, there were 99 cases with International Labor Organization chest radiologic criteria for CWP and 160 controls (with no radiologic criteria for CWP). Individual dust exposure variables were estimated from work histories, and smoking information was obtained from interviews. Polymerase chain reaction-based techniques evaluated the genotypes of all study subjects. There were no differences in genotype frequency of MnSOD, GSTM1, GSTT1, and OGG1 between miners with CWP and miners without CWP, by logistic regression analysis. Cumulative dust exposures, but not genetic polymorphisms, were associated significantly with the presence of CWP. This study illustrates the complexity of factors that may contribute to the development of CWP.     

Respiratory outcomes among South African coal miners at autopsy

BACKGROUND: Studies of dose-response relationships between respiratory outcomes at autopsy and coal dust exposure are limited. The Pathology Automation System (PATHAUT) database of South African miners, is one of the largest autopsy databases of occupational lung disease. This study described the prevalence of respiratory outcomes among South African coal miners at autopsy, and determined whether dose response relationships existed between emphysema and exposure. METHODS: Autopsies conducted from 1975 to 1997 on coal miners with exclusive coal mining exposure and having exposure duration information (n = 3,167) were analyzed from PATHAUT. Logistic regression was used to determine relationships between exposure and outcomes, controlling for race, smoking and age on a subset for whom smoking history was available (n = 725). RESULTS: The mean duration of exposure was 11.0 years. Most were black miners (75.3%) with significant differences in the mean ages of black and white miners (37.9 and 55.3 years, respectively). Only 22.9% of cases had information on smoking. The prevalence of silicosis, tuberculosis (TB), coal workers' pneumoconiosis (CWP), and moderate and marked emphysema were 10.7%, 5.2%, 7.3%, and 6.4%, respectively. All diseases, except TB, were associated with exposure duration. Black miners had 8.3 and 1.2 fold greater risks for TB and CWP, respectively, than white miners. White miners had an increased risk of 1.4 and 5.4 for silicosis and moderate to marked emphysema, respectively. In models unadjusted for age, and including smoking, moderate to marked emphysema was strongly associated with exposure duration (OR = 3.4; 95% CI = 1.9-5.9 for highest tercile of exposure duration). Exposure-related risk estimates were reduced when age was introduced into the model. However, age and duration of exposure were highly correlated, (r = 0.68) suggesting a dilution of the exposure effect by age. CONCLUSIONS: There were significant dose related associations of disease, including emphysema, with coal dust exposure.     

Exposure-response analysis of mortality among coal miners in the United States

The quantitative relationship between exposure to respirable coal mine dust and mortality from nonmalignant respiratory diseases was investigated in a study of 8,878 working male coal miners who were medically examined from 1969 to 1971 and followed to 1979. Exposure-related mortality was evaluated using Cox proportional hazards modeling for underlying or contributing causes of death and modified lifetable methods for underlying causes. For pneumoconiosis mortality, the lifetable analyses showed increasing standardized mortality ratios (SMRs) with increasing cumulative exposure category. Significant exposure-response relationships for mortality from pneumoconiosis (P < 0.001) and from chronic bronchitis or emphysema (P < 0.05) were observed in the proportional hazards models after controlling for age and smoking. No exposure-related increases in lung cancer or stomach cancer were observed. Pneumo coniosis mortality was found to vary significantly by the rank of coal dust to which miners were exposed. Miners exposed at or below the current U.S. coal dust standard of 2 mg/m³ over a working lifetime, based on these analyses, have an elevated risk of dying from pneumoconiosis or from chronic bronchitis or emphysema.     

Polymorphisms in the promoter of the tumor necrosis factor-α gene in coal miners

Tumor necrosis factor-α (TNF) is recognized as a central mediator of mineral dust-induced lung fibrosis, and genetic polymorphisms of the TNF promoter have been reported to influence levels of TNF production. To assess whether polymorphisms within the TNF promoter gene are associated with susceptibility to coal workers' pneumoconiosis (CWP), the DNA of 78 coal miners was typed for G-to-A transitions at positions −238 and −308. Our results show that frequency of A⁻³⁰⁸ genotype (T2) is significantly overpresented in coal miners with CWP (50%), as compared with miners without CWP (25%) and controls (29%). After correction for cumulative dust exposure and smoking, the A⁻³⁰⁸ transition genotype is still associated with the presence of CWP (OR = 3.0, 95%CI = 1.0–9.0). Both A⁻²³⁸ and A⁻³⁰⁸ transition genotypes were related to TNF release from endotoxin-stimulated blood monocytes; only the A⁻²³⁸ transition and not the A⁻³⁰⁸ transition was associated to coal dust-induced TNF release. In summary, this study shows that the A⁻³⁰⁸ transition is related to CWP, but this relation is not paralleled by a different TNF release in this genotype. A larger number of patients coupled to frequent TNF release are required to evaluate genotype screening to estimate individual health risks for effects of coal mine dust exposure. Am. J. Ind. Med. 34:318–324, 1998. © 1998 Wiley-Liss, Inc.     

煤尘职业接触者和早期煤工尘肺BAL液中表面活性物质研究

目的 探讨煤尘职业接触者和早期煤工尘肺患者BAL液中表面活性物质含量改变特点及其意义。方法 采煤工人23人,按X线诊断煤工尘肺期别分为0期（煤尘接触者）组7人、0^ 组8人和I期组8人,并取健康农民7人为对照组。经纤维支气管肺泡灌洗（BAL）收集BAL液,测定表面活性蛋白A(SP－A）和磷脂（PL）及其组分含量。结果 0期组BAL液中SP－A含量、SP－A／PL和PG／PI明显高于对照组（P＜0．01）,且随煤工尘肺期别增加而有降低趋势。结论 BAL液中SP－A含量、SP－A／PL和PG／PI升高可能是煤尘接触的早期效应指标。     

Association between lymph node silicosis and lung silicosis in 4,384 German uranium miners with lung cancer

This study investigates the association between lymph node-only and lung silicosis in uranium miners with lung cancer and exposure to quartz dust. Tissue slides of 4,384 German uranium miners with lung cancer were retrieved from an autopsy archive and reviewed by 3 pathologists regarding silicosis in the lungs and lymph nodes. Cumulative exposure to quartz dust was assessed with a quantitative job-exposure matrix. The occurrence of silicosis by site was investigated with regression models for exposure to quartz dust. Miners with lung silicosis had highest cumulative quartz exposure, followed by lymph node-only silicosis and no silicosis. At a cumulative quartz exposure of 40 mg/m(3) × years, the probability of lung silicosis was above 90% and the likelihood of lymph node-only silicosis and no silicosis do not differ anymore. The results support that lymph node silicosis can precede lung silicosis, at least in a proportion of subjects developing silicosis, and that lung silicosis strongly depends on the cumulative quartz dose.     

Mortality of Dutch coal miners in relation to pneumoconiosis, chronic obstructive pulmonary disease, and lung function.

OBJECTIVES: To analyse the mortality patterns of former Dutch coal miners, focusing on coal workers' pneumoconiosis (CWP) and chronic obstructive pulmonary diseases (COPD) in relation to pre-existing impairment of lung function. METHODS: 3790 selected miners, medically examined between 1952 and 1963, were followed up to the end of 1991 with the municipal population registries and the causes of death from the death certificates were ascertained and converted to the codes from the ninth revision of the international classification of diseases (ICD-9). Mortality comparisons were made with the male population in The Netherlands, resulting in standardised mortality ratios (SMRs). 3367 miners had radiological manifestation of CWP at medical examinations. RESULTS: 80% of the miners died during the follow up period. Excess mortalities from CWP (SMR 4523) and COPD (SMR 179) were found. Coal miners without CWP also showed an increased mortality from COPD (SMR 2913). A diminished lung function (forced expiratory volume in one second (FEV1), or FEV1/FVC (forced vital capacity) ratio) at medical examination resulted in a significantly increased SMR for COPD (322 and 212 respectively) whereas normal lung function yielded expected mortalities from COPD. A positive correlation also emerged between diminished lung function and the SMR due to CWP. The body mass index (BMI) at the moment of medical examination was correlated with the risk of dying of COPD and CWP: a decreasing BMI resulting in an increased SMR. CONCLUSIONS: Not only infectious diseases and CWP but also COPD is an important cause of occupational mortality in miners with extensive exposure to coal mine dust. No obvious connection between pre-existing CWP and the COPD mortality exists. Impaired FEV1 and FEV1/FVC ratios are predictors of an increased risk of COPD death. The BMI seems to indicate the severity of the COPD, resulting in premature death.