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.     

Lung mechanics in relation to radiographic category of coalworkers'' simple pneumoconiosis

ABSTRACT The maximal expiratory flow/static transpulmonary pressure relationship and the maximal expiratory flow response to breathing oxyhelium were used to distinguish between loss of elastic recoil and narrowing of small airways in 36 lifelong non-smoking non-bronchitic South Wales coalminers. On average the miners showed significantly (p < 0·05) reduced lung elastic recoil when compared with 10 healthy similarly aged non-miners. The mean forced expiratory volume in one second and the forced expiratory flow response to oxyhelium at 50% of the vital capacity were significantly (p < 0·05) lower in 12 miners with radiographic categories 2 or 3 when compared with 24 similarly aged miners with radiographic categories 0 or 1. The miners with categories 2 or 3 coalworkers' simple pneumoconiosis (CWP) had worked underground for 10 years longer, and their mean residual volume, residual volume/total lung capacity ratio, volume of isoflow and critical transmural pressure were significantly higher (p < 0·05). The results indicate that in the prodromal and early stages of simple CWP (categories 0 and 1), the dominant pathophysiological abnormality is loss of elastic recoil suggesting the presence of “focal emphysema.” As simple CWP progresses to categories 2 and 3, the loss of recoil is maintained, and the small airways become narrower. These findings are consistent with the hypothesis that progression of simple CWP is associated with the development of both centrilobular emphysema and intrinsic narrowing of small airways.     

肿瘤坏死因子-α与尘肺、肺结核关系的研究进展

肿瘤坏死因子-α的表达水平及其基因多态性与尘肺、结核的发病及进展程度有一定的联系.可通过对肿瘤坏死因子-α的进一步了解来逐步揭示尘肺与尘肺结核之间的关系,为尘肺、结核的一级预防提供线索.     

Coalworkers' pneumoconiosis: correlation between opacity profusion and number and type of dust lesions with special reference to opacity type.

The relation between the profusion and predominant type of small rounded opacities on chest radiographs taken within four years of death and the postmortem counts of dust lesions in four classes (macules, "pinhead" fibrotic nodules, nodules 1-3 mm, and nodules greater than 3-9 mm in diameter) has been examined for 71 coalworkers without progressive massive fibrosis. The radiographs were categorised by four readers independently, according to the ILO classification. For subjects considered by each reader to present predominantly p type opacities, increasing opacity profusion was exclusively and significantly associated with an increase in the number of pinhead fibrotic nodules. Numbers of nodules measuring 1-3 mm and greater than 3-9 mm in diameter both showed significant linear associations with opacity profusion category in subjects presenting predominantly q opacities, the closer association being observed with the smaller lesions. These observations held true for all readers. Opacities of type r were rarely considered to be the predominant type. For the reader who recorded the maximum number of such cases, opacity profusion was not significantly related to the numbers of dust lesions in any of the lesion classes. Nevertheless, the closest association was observed with nodules measuring greater than 3-9 mm in diameter. An overall significant linear association between total lung dust content and opacity profusion was found to be due mainly to subjects presenting predominantly p type opacities and to a lesser extent to those with predominantly q opacities.     

Lung gas exchange in simple pneumoconiosis of coal workers

Cotes, J. E., and Field, G. B. (1972).Brit. J. industr. Med.,29, 268-273. Lung gas exchange in simple pneumoconiosis of coal workers. Indices of lung function and gas exchange, including some based on measurement of the arterial blood gases and physiological response to exercise, were obtained in 19 coal workers with simple pneumoconiosis of the pinhead or micronodular type, of whom 11 also had bronchitis. p-Type pneumoconiosis differed from the m-type in being associated with a smaller transfer factor, larger physiological deadspace relative to tidal volume (Vd/Vt), and increased ventilation during submaximal exercise. Vd/Vt was also raised in patients with bronchitis. The venous admixture effect (including physiological shunt) was within normal limits. Breathing oxygen increased Vd/Vt in patients with bronchitis but not with p-type pneumoconiosis. The findings are evidence for p-type pneumoconiosis being associated with abnormal function of the lung parenchyma; the changes are consistent with cystic lung.     

The radiographic categorization of coal workers' pneumoconiosis by lay readers

An investigation was carried out to show whether lay readers could be trained to interpret chest radiographs for coal workers' pneumoconiosis. It was shown, first, that lay readers can be trained for this purpose, and second, that they are no more prone to interobserver variation than are physicians. Once again, the extent of the interobserver variation among experienced readers in the categorization of the films for coal workers' pneumoconiosis was shown to be greater than is commonly realized.     

尘肺期别及小阴影类型对煤工尘肺的肺部感染影响

目的了解煤工尘肺不同期别、不同的小阴影类型对煤工尘肺肺部感染的影响,为早期干预、诊断、治疗煤工尘肺肺部感染提供早期科学依据。方法收集从2006年6月—2008年6月住院的所有的煤工尘肺患者,并按照不同的尘肺期别、不同的小阴影类型进行分类,根据分类情况分析其肺部感染发生的情况,找出尘肺期别及小阴影类型与尘肺肺部感染之间关系的规律性。结果①Ⅰ期煤工尘肺患者318人,出现肺部感染人数194人,感染率61.00%（194/318）;Ⅱ期煤工尘肺患者134人,出现肺部感染人数86人,感染率64.18%（86/134）;Ⅲ期煤工尘肺患者28人,出现肺部感染人数26人,感染率92.85%（26/28）。3组相互比较,差异有统计学意义（P〈0.01）。②按照尘肺小阴影类型分类,具有类圆形小阴影人数321人（包括p178、q133、r10）;其中出现肺部感染人数186人,具有不规则形小阴影人数159例（包括s78、t59、u22）,其中出现肺部感染人数120人。两组比较,差异有统计学意义。同时又分别对具有类圆形小阴影中3组小阴影人数和具有不规则形小阴影中3组小阴影人数进行统计学分析,差异均无统计学意义。结论①煤工尘肺期别对煤工尘肺肺部感染有影响,尘肺期别越高尘肺合并肺部感染人数越多,合并肺部感染的危险性越高。②煤工尘肺小阴影类型对尘肺合并肺部感染有影响,不规则小阴影较类圆形小阴影更容易合并肺部感染。③同一类型小阴影对尘肺肺部感染的影响差异无统计学意义。     

煤工尘肺患者肺通气功能障碍的影响因素

目的分析煤工尘肺(CWP)患者肺功能障碍的可能影响因素。方法采用病例-对照研究,分别选择141名CWP患者为病例组,200名非CWP的接尘矿工为接尘组,75名非从事接尘作业的健康者为对照组,均为男性。对研究对象调查接尘工种、接尘工龄、肺部疾病、吸烟及职业卫生防护情况等,并测定肺通气功能,根据对照人群特征建立相应肺功能指标的预计回归方程计算预计值,以各指标的实测值和预计值之比对肺功能障碍进行分型,采用非条件Logistic回归模型对影响因素进行分析。结果病例组及接尘组FVC、FEV_(1.0)实测值及FVC、FEV_(1.0)实测值与其预测值的比值均明显低于对照组,差异有统计学意义(P<0.05);随煤工尘肺分级增加,限制性和混合性通气功能障碍发生率明显增高(x~2=67.46,51.19,P<0.05);佩戴口罩情况、CWP分期、吸烟程度、接尘工龄等指标均被选入非条件Logistic回归模型。结论影响煤工尘肺患者肺功能障碍的因素可能有CWP晋级、是否坚持佩戴口罩、吸烟、接尘工龄等。     

煤工尘肺潜在结核感染的化学预防

目的观察煤工尘肺潜在结核感染联合服用异烟肼、利福平化学预防尘肺结核的效果。方法将448例煤工尘肺潜在结核感染患者按尘肺期别、年龄分为两组,一组为投药组,采用异烟肼、利福平联合服用3个月,间断3个月,再服3个月,晨起顿服,另一组为同期对照组,观察5年中两组尘肺结核发病情况。结果通过5年临床观察,有效观察例数421例,投药组213例患者中尘肺结核7例(3.29%),对照组208例患者中尘肺结核29例(13.94%),两组比较差异有非常显著性(P<0.01)。其中Ⅰ期投药组尘肺结核0例,对照组8例(7.34%),差异有显著性(P<0.05);Ⅱ期投药组尘肺结核1例(1.45%),对照组9例(13.64%),差异有显著性(P<0.05);Ⅲ期投药组尘肺结核6例(16.22%),对照组12例(36.36%),差异无显著性(P>0.05)。结论对煤工尘肺潜在结核感染的化学预防可以降低各期煤工尘肺结核的患病率,Ⅰ、Ⅱ期效果显著。     

煤工尘肺肺动脉病变的定量分析

[目的]研究煤工尘肺(CWP)肺细小动脉病变与肺心病的关系.[方法]取48例矿工尸检肺组织和12例非矿工手术标本进行了病理观察.对外径＜200μm的细小动脉在光镜观察的基础上用德国Kontron公司IBAS/Ⅱ图象分析仪进行测试.[结果]尘肺组细小动脉壁增厚与对照组相比EA/TA、WA/TA、WD/TD三项比值,Ⅰ期尘肺差异有显著性(P＜0.05),ⅡⅢ期差异有非常显著性(P＜0.01),ⅡⅢ期与Ⅰ期相比60～200μm小动脉差异有显著性(P＜0.05)说明CWP肺血管病变范围随尘肺病变加重而加重,CWP肺细小动脉壁尘细胞沉积及尘性纤维化是造成肺血管硬化使其顺应性降低的主要原因之一.与年龄因素相比,尘肺细小的动脉病变与粉尘破坏作用有更大关系.吸烟也不足以掩盖粉尘对血管这的损伤作用.[结论]尘性气管炎和尘斑气肿是导致煤工尘肺肺动脉高压的主要原发疾病.     

An elaboration of small opacity types (p, m, and n) in simple pneumoconiosis

Lindars, D. C. (1971).Brit. J. industr. Med.,28, 131-142. An elaboration of small opacity types (p, m, and n) in simple pneumoconiosis. According to the I.L.O. classification (International Labour Office, 1959), radiographs showing pneumoconiosis may be classified as p, m or n according to the greatest diameter of predominant (small) opacities. Recent work has revealed pathological and physiological differences associated with these appearances.     

煤工尘肺肺心病肺小动脉病理改变观察

为探讨煤工尘肺肺心病病例肺小动脉的病理变化，我们选择30例煤工尘肺尸检病例进行观察研究，报告如下。