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[Pilot study of the prevalence of a hyperreactive bronchial system in various occupationally-induced lung diseases].

A pilot study was performed to assess the prevalence of hyperreactive bronchial system (HBS) in various occupational lung diseases. 204 patient records were evaluated with the following diagnosis: Allergic rhinitis: (N = 25, 12%), allergic bronchial asthma (N = 70, 34%), toxic asthma (N = 22, 11%), silicosis (N = 12, 6%), asbestosis (N = 15, 7%), farmer's lung (N = 12, 6%), chronic unspecific respiratory syndrome (N = 48, 24%). In each case an inhalative methacholine test (MCHT) was performed. HBS was considered to be present whenever there was a resistance increase of more than 100% of the baseline values. The prevalence of HBS varied between 50% (asbestosis) and 77% (toxic asthma); the average was 68%. Allergic diseases showed a higher prevalence of 71% in comparison to nonallergic diseases with 65%. Patients with silicosis or asbestosis and without additional chronic bronchitis or emphysema demonstrate a "normal" prevalence of HBS of 11%. Age, gender, smoking, alcohol, family history of allergy and repeated bronchitis, the number of eosinophils in the blood. IgE concentration in serum showed no significant association with an increased prevalence of HBS. The coincidence of anamnestically affirmed or denied bronchial hypersensitivity to environmental factors, and the positive or negative result of the MCHT test, was relatively low, being only 43% in case of a "positive" test and 17% in case of a "negative" test.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Issues and controversies in the plain-film diagnosis of asbestos-related disorders in the chest.

This article reviews the chest radiographic manifestations of asbestos exposure. While the chest radiograph (CXR) is a highly valuable tool in the evaluation of asbestos-related disease, there are ongoing controversies regarding the sensitivity and specificity of the plain film in diagnosing asbestos-related disorders. Autopsy series indicate that at least 60% of pleural plaques may be overlooked. Conversely, such series indicate that up to 20% of plaques are falsely diagnosed. The significance of visceral pleural thickening and the definition and positive predictive value of diffuse pleural thickening as they relate to asbestos exposure are unresolved issues. Data suggest that the CXR may fail to reflect significant asbestosis in 10% to 20% of cases. On the other hand, the presence of overlying pleural abnormalities as well as technical factors may contribute to overreading of interstitial disease. Data on the rate of false positive readings for asbestosis are limited. Considered alone, the CXR can support but not specifically establish nor exclude the diagnosis of asbestosis. In practice, an ILO grade of less than 1/0 implies that the diagnosis is unlikely. A constellation of positive CXR findings may increase specificity, although the diagnosis rests on a combination of multiple clinical criteria.

Asbestos↗

Evaluation for compensation of asbestos-exposed individuals. I. Detection and quantification of asbestos-related nonmalignant impairment.

An objective method for measuring nonmalignant respiratory impairment caused by inhaled asbestos has been devised. Three standard physiologic tests (the forced vital capacity [FVC], the forced expiratory volume in 1 s [FEV1], the single-breath diffusing capacity for carbon monoxide [DCO]) and the posteroanterior chest roentgenogram are utilized. The age-, height-, and sex-specific normal ranges of the FVC%, the DCO%, and the FEV1/FVC% have been used in the method. The theory and rationale are described. The resulting algorithm can be presented using a nomogram. Data on 586 asbestos-exposed subjects were analyzed by the proposed method. Empirical evaluation showed the sensitivity to be greater than 90% in definitive diagnosis of asbestosis without airflow obstruction, and the specificity to be greater than 80% for those cases judged eligible for nomographic evaluation. Exceptions were found in 15 cases diagnosed clinically as asbestosis, none of whom had any evidence of pulmonary fibrosis. In addition, 50 cases diagnosed as "no asbestosis" did have evidence of pulmonary fibrosis and would have qualified for some compensation by the proposed method. In summary, this approach has been shown to yield a reliable final asbestos-related lung impairment index that, when taken together with individual societal data, can provide a reliable basis for determining compensation.

Aged↗

[Current occupational respiratory pathology in Switzerland].

The main features of occupational industrial respiratory diseases in Switzerland can be summarized as follows: -Silicosis: 9750 cases from 1930 to 1979. At present low annual incidence (less than 100 cases), age at first diagnosis over 40 years, at death almost 70 years. - Asbestosis: 130 cases from 1939 to 1979. 30 cases of mesothelioma (21 without asbestosis; 9 with), 9 of bronchial carcinoma and 1 of gastric cancer in the 130 cases of asbestosis. - Acute toxic lung (irritant gases such as chlorine, phosgene, nitrous gases), occupational asthma, extrinsic alveolitis and finally occupational chronic bronchitis are the principal diseases also observed.

Adult↗

[Occupational risk of asbestos injuries among workers in the asbestos cement industry].

Dustiness in the asbestos-cement production department of the "Vulkan" plant in Dimitrovgrad was studied. The assay included concentration, dispersion, substance composition, morphology, asbestos content. Two types dustiness were encountered: In the storage and mixing shops the aerosol contained 7 to 78 percent asbestos needles, free from agglomeration; in the moulding and turnery shops the asbestos content rangeal from 2 to 21 percent. Considerable part of the needles were amalgamated by the cement and could be detected only on electron-microscopic observation. The total amount of inhaled asbestos exceeded the amount inhaled at threshold concentration of 0.2 mg pure asbestos aerosol 9 times in the preparatory division and from 2 to 14 times in other shops. In the moulding shop the content was lower than the threshold one. Elevel cases of asbestosis were established: 3 in the preparatory, 4 in the turnery and 3 in other shops. In five cases there were pleural plaques in addition to the parenchymal changes. The minimal length of service to develop asbestosis was 13-14 years at the preparatory division (more free asbestos in the aerosol) and 20-21 years at the turnery shop (less, but agglomerated asbestos). Work with asbestos-cement exposes the workers to a serious risk of development of asbestosis. No principal difference was established in the biologic activity of the two aerosol types; there only is a difference in the degree of their aggressiveness.

Air Pollutants, Occupational↗

[Evolution of radiologic changes in lungs of workers occupationally exposed to asbestos dust].

The dynamic of radiological changes in lungs of 458 workers exposed to chrysotile asbestos dust and in 65 retired workers previously exposed to the same dust was assessed. There was a 5-year interval between initial and control examinations in the group of acting workers and an 8-year interval in the group of retired workers. The control examination of workers with employment below 10 years did not reveal radiological changes which could indicate asbestosis. In the group of 400 workers with employment over 10 years new cases of asbestosis were diagnosed in 34 persons (8.5%) during the control examination. During the control examination progress of pleural changes was observed in 4% of males and 3.8% of females. As the period of exposure to asbestos had expanded the occurrence of small, irregular shadows, especially in persons working longer than 15 years, was more often noticed. The aforesaid aberrations have progressed in 11.7% of males and 9.5% of females when compared with the results of the initial examination. In the group of retired workers 15 (23.1%) new cases of asbestosis were detected 8 years after the termination of occupational exposure. Small, irregular shadows, limited in number as well as pleural changes have progressed in approximately 22% of retired males and females.

Asbestos↗

[A 5-year before-and-after comparison of lung function in asbestos workers].

A 5-year before-and-after comparison of lung function was carried out in 119 male asbestos workers. Of them 50 were healthy workers (0), 25 were patients with suspectable asbestosis (0+), 36 with Stage I asbestosis (Ias) and 8 with Stage II asbestosis (II as). The findings measured for before and after 5 years revealed that FVC, FEV and DLco declined in the four groups over the whole period of observation. The decrease in FVC and DLco was most marked and the differences were statistically significant (P < 0.05). Comparison among four groups showed that all indices of lung function in Group II as reduced significantly after 5 years (P < 0.01), indicating a rapid decrease of lung function in Group II as. It is suggested that FVC and DLco are the most sensitive indices in detecting very early abnormalities of lung function in asbestos workers.

Adult↗

Increased sensitivity to asbestos-induced lung injury in mice lacking extracellular superoxide dismutase.

Asbestosis is a chronic form of interstitial lung disease characterized by inflammation and fibrosis that results from the inhalation of asbestos fibers. Although the pathogenesis of asbestosis is poorly understood, reactive oxygen species may mediate the progression of this disease. The antioxidant enzyme extracellular superoxide dismutase (EC-SOD) can protect the lung against a variety of insults; however, its role in asbestosis is unknown. To determine if EC-SOD plays a direct role in protecting the lung from asbestos-induced injury, intratracheal injections of crocidolite were given to wild-type and ec-sod-null mice. Bronchoalveolar lavage fluid (BALF) from asbestos-treated ec-sod-null mice at 24 h, 14 days, or 28 days posttreatment showed increased inflammation and total BALF protein content compared to that of wild-type mice. In addition, lungs from ec-sod-null mice showed increased hydroxyproline content compared to those of wild-type mice, indicating a greater fibrotic response. Finally, lungs from ec-sod-null mice showed greater oxidative damage, as assessed by nitrotyrosine content compared to those of their wild-type counterparts. These results indicate that depletion of EC-SOD from the lung increases oxidative stress and injury in response to asbestos.

Animals↗

Emphysema findings associated with heavy asbestos-exposure in high resolution computed tomography of finnish construction workers.

Asbestos fibers are known to cause lung fibrosis, but their role in emphysema is unclear. We wanted to evaluate the relationship between asbestos exposure and emphysema by using high-resolution computed tomography (HRCT). Conventional and high resolution CT was performed on 600 smoking construction workers with an asbestos-related occupational disease. Emphysema subtypes (centrilobular, paraseptal, panlobular emphysema and bullae) were separately scored on a semiquantitative scale from 0 to 5, which scores were added up to yield the total emphysema score. Occupation, exposure duration, age, pack years and asbestosis diagnosis were analyzed in general linear models for possible associations with emphysema. The inter- (quadratic weighted kappa, kappa(qw)=0.46-0.72) and intraobserver (kappa(qw)=0.78-0.94) agreements for the subtype-scores and the reliability of the total score (Cronbach's alpha=0.87) were good. Insulators had a significantly higher paraseptal, panlobular and total score than the other occupational groups when adjusted for age and smoking. An asbestosis diagnosis was also a significant independent predictor of a higher total score. Emphysema was more common when workers had asbestosis or were heavily exposed to asbestos (insulators), but due to confounding factors the causative role of asbestos in emphysema needs further study.

Adult↗

Effects of asbestos and smoking on gas diffusion in people exposed to crocidolite.

OBJECTIVE: To examine the effects of asbestos exposure and tobacco smoking on the level and rate of change of the diffusing capacity of the lung for carbon monoxide (DLCO). DESIGN AND PARTICIPANTS: A cohort study of 934 people (including both mine workers and town residents) exposed to crocidolite (blue asbestos) at the asbestos mines and in the town of Wittenoom, Western Australia, between 1943 and 1966. DLCO measurements were taken during a follow-up period from 1992 to 2002. MAIN OUTCOME MEASURES: Baseline levels of DLCO and change in levels over time. RESULTS: 2980 DLCO measurements were done on 934 people (of whom 818 were men and 724 were workers) who underwent a median of 2 (range, 1-17) measurements during the follow-up period. Radiographic asbestosis at baseline and asbestos exposure at a younger age were associated with lower DLCO values. The average rate of decline in DLCO was 0.33 (95% CI, 0.31-0.35) units per year, plus an additional decrement of 0.22 (95% CI, 0.12-0.32) units per year if the participant had radiographic asbestosis at the beginning of the follow-up period. Compared with never-smokers, current smokers and ex-smokers had lower DLCO at baseline, but smoking status did not affect the change in DLCO during the follow-up period. CONCLUSIONS: Our results confirm a continuous deleterious effect of crocidolite on DLCO, especially on people with asbestosis. Smoking was associated with lower DLCO levels, but was not a significant predictor of rate of change in DLCO. Smoking status did not affect the relationships between crocidolite exposure and the level or rate of change of DLCO in this population.

Age Distribution↗

Mortality from malignant neoplasms among workers of an asbestos processing plant in Poland: results of prolonged observation.

OBJECTIVES: The study on mortality from cancer among workers of an asbestos plant manufacturing asbestos yarn, cloth, cords, packings, stuffing, brake linings and asbestos-rubber sheets was launched in the 1980s. The present paper discusses the results of further tracing of asbestos workers of the same plant. MATERIALS AND METHODS: The study cohort covered 4497 workers employed at the asbestos plant in 1945-1980. The follow-up of the cohort continued until 31 December 1999. Deaths by causes were analyzed using standardized mortality ratio (SMR) calculated by the person-years method. The mortality pattern of the general population of Poland was used as reference. RESULTS: The availability of the cohort was 93.1% (2805 men and 1382 women were traced). Mortality from malignant neoplasms in total (281 deaths among men, SMR = 118, 95%CI: 105-133 and 135 deaths among women, SMR = 159, 95%CI: 133-188) as well as that from lung cancer (102 deaths among men, SMR = 126, 95%CI: 103-153 and 18 deaths among women, SMR = 259, 95%CI: 153-409) were significantly higher than in the general population. Unlike earlier stages of analysis, the present study revealed an increased risk of pleural mesothelioma (2 deaths among men, SMR = 510, 95%CI: 62-1842 and 3 deaths among women, SMR = 2033, 95%CI: 419-5941). Mortality analysis among workers with asbestosis and in those without diagnosed asbestosis, did not reveal direct association between the risk of asbestos-induced lung cancer and previously diagnosed asbestosis. CONCLUSIONS: The prolonged cohort tracing showed an increased risk of asbestos-related cancers. It concerned mainly workers hired by the plant between 1945-1955, when the working condition were most strenuous.

Adult↗

[Lung cancer in a female non-smoker with occupational exposure to asbestos: a case report].

BACKGROUND: Until recently, asbestos was widely used in a variety of industrial processes. Workers exposed to asbestos may develop lung and pleural diseases such as asbestosis, lung cancer, benign pleural effusion, pleural plaques and mesothelioma. OBJECTIVE: To describe a clinical case of lung cancer in a female non-smoker with occupational exposure to asbestos. METHODS: The clinical and occupational history was based on the information kindly provided by the Occupational Unit of the National Health Service and on the case history of a hospital admittance in 2001, when the patient underwent surgery for lung cancer. RESULTS: The patient worked for 6 years in an asbestos manufacturing industry where she was exposed to high concentrations of asbestos, and then worked for 14 years in a sugar refinery only during the summer. She had benign pleural effusion, pleural plaques, asbestosis and lung cancer. CONCLUSIONS: We concluded that a six-year exposure to high doses of asbestos may induce lung cancer and asbestosis in a female non-smoker.

Asbestos↗

Spectrum of occupational disease in an academic hospital-based referral center in Connecticut from 1979 to 1987.

The inability to characterize the extent of occupational disease in the United States limits clinical diagnosis and public health interventions. We present an 8-year (1979 to 1987) experience with clinic-based reporting in Connecticut. Altogether, 3566 cases were sequentially coded for demographics, diagnoses, workplace identification, and exposures at two academic occupational medicine clinics. The lungs were the principal organs of diagnosed effect, with asbestos-related disorders predominating, whereas the urinary tract, endocrine organs, and cardiovascular systems were rarely involved. Of all diseases, 64.8% were diagnosed as chronic and irreversible. Three common disorders, lead intoxication (acute and chronic), asbestosis, and occupational asthma were selected for illustration. Patients with lead poisoning and asbestosis, although collectively numerous (40 and 504, respectively), came from a small number of worksites and industries. Occupational asthma was more variable: 141 diagnosed cases came from 56 different trades and industries and were caused by 28 recognized agents. While we recognize that clinic-based reporting suffers from obvious problems with referral bias and misclassification, our experience shows that it provides an important index of disease burden. Our data document the effects of legislation and litigation on lead poisoning and asbestosis, and correspondingly helps characterize diseases that will respond to broad intervention. On the other hand, occupational asthma is more pervasive and would require a more specialized, partially clinical approach.

Adult↗

[CT findings of diffuse pleural disease--alteration of pleura and extrapleural fat].

This is a comprehensive study on the usefulness of CT in the evaluation of diffuse pleural diseases in 114 patients. Alterations of the pleura and extrapleural fat were analyzed. The pleural changes were classified into five groups: no thickening (group 1), focal thickening (group 2), diffuse smooth thickening (group 3), diffuse nodular thickening less than 10 mm (group 4), diffuse nodular thickening more than 10 mm (group 5), CT findings of group 1 were mostly found in patients with transudatory effusion; group 2 in all patients with asbestosis; group 3 in those with empyema; and group 4 and 5 in those with malignant pleural diseases. In some cases with malignant pleural diseases and asbestosis, mediastinal and/or fissural thickening was present. Circumferential pleural thickening (pleural rind) was only seen in malignant pleural diseases. Pleural calcification was present in chronic empyema and asbestosis. Increased thickness of the extrapleural fat was seen in malignant pleural diseases and empyema, but homogeneous increased attenuation of the extrapleural fat might be a specific finding in acute empyema. The author concludes that CT is useful in the evaluation of pleural changes and alterations of extrapleural fat with diffuse pleural diseases, particularly in the pattern recognition based on CT classification.

Adipose Tissue↗

Hospital records: an underutilized source of information regarding occupational diseases and exposures.

A 1993 study examined the association between pneumoconiosis and cor pulmonale using a computerized data base of hospital records in Ontario (Hospital Medical Records Institute, HMRI). The present investigation was undertaken to confirm the coding of the diagnoses of a subset of the hospital discharges from that study, to determine the validity of the coding of the diagnoses of coal workers' pneumoconiosis (CWP), and to identify work exposure (occupation and industry) information available in hospital records. We sent abstraction forms to hospitals for 521 subjects who were hospitalized for pneumoconiosis, cor pulmonale, or both conditions, requesting information regarding diagnoses, occupation and industry data, and X-ray results. Abstracts were received for 720 (76%) of 944 discharges that were sought. The hospital abstractions confirmed the HMRI coding for 90% of the charts with these conditions, including 63%, 97%, and 96% discharges for CWP, silicosis, and asbestosis, respectively. Specific dust exposures were indicated in 42% of the charts with a code indicating a diagnosis of CWP, and of these, 67% indicated exposure to coal dust. Of charts with a code indicating a diagnosis of silicosis, 73% with specific dust information indicated silica exposure, and 95% of those for asbestosis indicated exposure to asbestos. Of 34 individuals in this data set known from the Ministry of Labour's Chest Clinic X-ray Surveillance Program of miners to have silicosis, 33 (97%) were diagnosed by the hospitals as having pneumoconiosis, and all but two were silicosis. Hospital records, as reflected by HMRI data, are reliable indicators of cor pulmonale and pneumoconiosis. The agreement with the Chest Clinic's X-ray diagnoses provides additional objective confirmation of the accuracy of the hospital information. There were relatively few cases of silicosis miscoded as CWP. At least for pneumoconioses, hospital records contained information about the exposures that led to these diseases in approximately 50% of the cases. However, whether hospital records would prove useful for detecting other work-related conditions that are not pathognomonic of occupation is not known. The importance of taking occupational histories needs continued emphasis in medical education and training.

Asbestosis↗

Latency of asbestos disease among insulation workers in the United States and Canada.

Two thousand two hundred seventy-one deaths were recorded among 17,800 asbestos insulation workers observed from January 1, 1967-December 31, 1976. There was little increase in cancer deaths or of asbestosis in less than 15-19 years from onset of employment. In general, though, the period of clinical latency was 2-4 decades or more and there were important differences among the several asbestos-associated diseases. Lung cancer peaked at about 30-35 years from onset and asbestosis at 40-45 years. Each tended to decline in incidence afterwards. Pleural and peritoneal mesothelioma reached their highest incidence later than lung cancer, but the incidence did not decline. In studies of effects of asbestos exposure, it appears advantageous to observe for at least 35-40 years or more from onset of exposure and to analyze the experience in duration-from-onset categories. If this is not possible, only the very limited early effects will be identified and the full import of the exposure may not be appreciated.

Adolescent↗

Previously undetected silicosis in New Jersey decedents.

BACKGROUND: Despite a reported decline in mortality and hospitalizations associated with silicosis [U.S. Department of Health and Human Services, 1999], this decline may be artifactual, stemming in part from underdiagnosis by physicians. METHODS: This study estimates, through radiological confirmation, the prevalence of unrecognized silicosis in a group of silica-exposed New Jersey decedents whose cause of death was chronic obstructive pulmonary disease (COPD), tuberculosis, or cor pulmonale. Two expert readers re-evaluated the chest X-rays of this group to determine the presence or absence of silicosis. The study population was considered to be presumptively exposed to silica dust by virtue of their usual industry of employment as listed on the death certificate. RESULTS: Radiographic evidence of silicosis was found in 8.5% of this population, and evidence of asbestosis was found in another 10.7%, for a total of 19.2%. CONCLUSIONS: The existence of previously unrecognized silicosis and asbestosis in 19.2% of this study group suggests that occupational lung disease is under-recognized and, hence, undercounted.

Aged↗

The British approach to asbestos standard setting: 1898-2000.

BACKGROUND: The asbestos industry started in the late 1870s, and the first accounts of severe respiratory disease in its workers were published in England (1898, 1906), France (1907), and Italy (1908). For a hundred years, a series of increasingly lower standards were set for asbestos in Britain: initially they purported to prevent asbestosis, and latterly to reduce asbestosis and malignancies to acceptable levels. METHODS: Published accounts of how British asbestos exposure standards came to be derived are reviewed in the light of archival materials originated by industry and government. RESULTS: The earliest standard, of necessity, was not evidence based and while subsequent standards purported to relate doses to effects, the indifferent quality of the measurement of dose, and the poor discrimination of effects, militated against arriving at a standard in which trust should be placed. Each successive standard that was accepted, conformed to what could be achieved in production processes, as far as it was reasonably practicable on technological and economic grounds. CONCLUSIONS: For the better part of a hundred years, confidence was misplaced in the ability of process engineers and physicians to protect workers against asbestos. Finally, deciding that asbestos was neither technologically nor economically essential, and was unsafe in use, Europe issued a Directive, to which Britain will conform, that will virtually ban it use throughout the Community by 2006.

Asbestos↗