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At least 19 recordsLinked to original sources
PubMed1996

Retention of asbestos fibres in lungs of workers with asbestosis, asbestosis and lung cancer, and mesothelioma in Asbestos township.

OBJECTIVE: To conduct a mineralogical study on the particles retained in the necropsied lungs of a homogenous group of asbestos miners and millers from Asbestos township (and a local reference population) and to consider the hypothesis that there is a difference in size between fibres retained in the lungs of patients with asbestosis with and without lung cancer. METHODS: Samples of lung tissue were obtained from 38 patients with asbestosis without lung cancer, 25 with asbestosis and lung cancer, and 12 with mesothelioma, from necropsied Quebec chrysotile miners and millers from Asbestos township. Fibre concentrations in the lungs of these patients were compared with those in tissue from necropsies carried out on a local reference population: men who had died of either accidental death or acute myocardial infarction between 1990 and 1992. 23 were born before 1940 and 26 after 1940. RESULTS: Geometric mean (GM) concentrations were higher in cases than in the controls for chrysotile fibres 5 to 10 microns long in patients with asbestosis with or without lung cancer; for tremolite fibres 5 to 10 microns long in all patients; for crocidolite, talc, or anthophyllite fibres 5 to 10 microns long in patients with mesothelioma; for chrysotile and tremolite fibres > or = 10 microns long in patients with asbestosis; and crocidolite, talc, or anthophyllite fibres > or = 10 microns long in patients with mesothelioma. However, median concentrations of each type of fibre in the lungs did not show any significant differences between the three disease groups. Average length to diameter ratios of the fibres were calculated to be larger in patients with asbestosis and lung cancer than in those without lung cancer for crocidolite fibres > or = 10 microns long, for chrysotile, amosite, and tremolite fibres 5 to 10 microns long, and for chrysotile and crocidolite fibres < 5 microns long. However, there was no statistical difference in the median length to diameter ratios for any type of fibres across the disease groups when they were calculated in each patient. Cumulative smoking index (pack-years) was higher in the group with asbestosis and lung cancer but was not statistically different from the two other disease groups. CONCLUSION: Lung cancers occurred in workers with asbestosis from Asbestos township who had an equal concentration of retained fibres but a tendency to a higher length to diameter ratio of amphiboles. These workers had a 29% higher average cumulative smoking index.

Adult↗
PubMed1984

Immunological aspects of asbestosis: patients' neurological signs and asbestosis progression.

This study is a component of a long-term, follow-up study aimed at evaluation of immunological and neurological findings with regard to the early detection of malignancies among patients at high risk of developing cancer. One hundred fifteen patients with diagnosed asbestosis were examined neurologically and immunologically (rheumatoid factor, antinuclear antibodies, C3 and C4 and circulating immune complexes). Patients with nervous system involvement (63 cases; 55%) revealed no significant immunological differences when compared with the other patients except for a more common presence of antinuclear antibodies among patients without nervous system involvement (21% vs 6%, p less than .05). Significantly increased Wa-Ro titers (greater than 1/128) were found for 3-4% of the patients whose asbestosis was either progressive or not as to radiological fibrosis, whereas only 0.4% of the blood donors had a significantly increased Wa-Ro titer. The respective figures of latex agglutination (greater than 1/32) were found for 14-19% of the asbestosis patients whereas in 0.8% of the blood donors. The mean level of C3 was higher among progressive than nonprogressive asbestosis cases (1.48 vs 1.34, p less than .05). Patients with radiographic progression of asbestosis had higher IgG-antinuclear antibody titers than the patients without progression.

Adult↗
PubMed1995

CT quantification of interstitial fibrosis in patients with asbestosis: a comparison of two methods.

OBJECTIVE: The likelihood of interstitial lung disease being detected on high-resolution CT scans and having functional significance is often related to the severity of the disease. The extent and severity of the abnormalities seen on high-resolution CT are usually assessed subjectively. This study was undertaken to investigate whether a subjective semiquantitative scoring method or a method using a cumulation of the different high-resolution CT features of asbestosis were comparable in suggesting asbestosis in a group of patients with histopathologic confirmation of disease. A secondary objective was to compare the results of these two high-resolution CT methods with chest radiographs in the same population. MATERIALS AND METHODS: This study group consisted of 24 patients and six lungs obtained at autopsy. Histopathologic asbestosis was present in 25 of the 30 patients or lungs. The patients or lungs were imaged using selected high-resolution CT scans. The high-resolution CT scans were assessed in two ways. One used a subjective semiquantitative extent and severity score consisting of four levels of severity, while the other was a cumulative score adding the different types of high-resolution abnormalities in asbestosis. The commonest high-resolution CT abnormalities in the cases with confirmed asbestosis were interstitial lines (84%), parenchymal bands (76%), and architectural distortion of secondary pulmonary lobules (56%). Subpleural lines and honeycombing were less frequent. The histopathologic severity of asbestosis was independently graded on a four-point scale. Chest radiographs, when available, were classified according to the International Labor Organization (ILO) classification of pneumoconioses. RESULTS: With the subjective semiquantitative high-resolution CT severity score, asbestosis was suggested in 16 (64%) instances, all with disease. With the cumulative method, any one type of abnormality was present in 88% of cases with asbestosis, two types in 78%, and three in 56%. However, to include only cases with asbestosis, three different abnormalities had to be present. The high-resolution CT scans were normal or near normal in five instances of asbestosis. Chest radiographs using the ILO classification predicted asbestosis with a lesser frequency than high-resolution CT in this selected population. CONCLUSION: We conclude that a subjective semiquantitative grading system of the extent and severity of asbestosis and a method using a cumulative addition of the different findings in asbestosis give similar results in suggesting the presence of disease. Thus, for the high-resolution CT detection of asbestosis, a combination of the cumulative number of different findings and an assessment of the extent and severity of the abnormalities could be complimentary. We also conclude that asbestosis can be present histopathologically with a normal or near normal high-resolution CT scan.

Aged↗
PubMed1997

Asbestos, asbestosis, and lung cancer: observations in Quebec chrysotile workers.

One prospective epidemiologic study of asbestos cement workers with radiological small opacities has been cited as a rationale for attributing excess lung cancer to asbestosis. This approach could have considerable practical value for disease attribution in an era of decreasing exposure. However, a recent International Agency for Research on Cancer review concludes that the mechanism of production of asbestos-related lung cancer are unknown. Asbestosis, therefore, cannot be a biologically effective dose marker of lung cancer susceptibility. Asbestosis nonetheless would be useful in identifying asbestos-attributable lung cancer cases if it could be proven an infallible exposure indicator. In this study, we tested this hypothesis in the chrysotile miners and millers of Quebec, Canada. We examined exposure histories, autopsy records, and lung fiber content for 111 Quebec chrysotile miners and millers. If the hypothesis of an asbestosis requirement for lung cancer attribution were accurate, we would expect as asbestosis diagnosis to separate those with lung cancer and high levels of exposure from those with lower levels of exposure in a specific and sensitive manner. This is the first such study in which historical job-based individual estimates based on environmental measurements, lung fiber content, exposure timing, and complete pathology records including autopsies were available for review. We found significant excesses of lung tremolite and chrysotile and estimated cumulative exposure in those with lung cancer and asbestosis compared to those with lung cancer without asbestosis. However, when the latter were directly compared on a case-by-case basis, there was a marked overlap between lung cancer cases with and without asbestosis regardless of the measure of exposure. Smoking habits did not differ between lung cancer cases with and without asbestosis. In regression models, smoking pack-years discriminated between those with the without lung cancer, regardless of asbestosis status. Most seriously, the pathologic diagnosis of asbestosis itself seemed arbitrary in many cases. We conclude that although the presence of pathologically diagnosed asbestosis is a useful marker of exposure, the absence of this disease must be regarded as one of many factors in determining individual exposure status and disease causation.

Aged↗
PubMed2004

Mortality, morbidity, and asbestosis in New Zealand: the hidden legacy of asbestos exposure.

AIMS: To examine the morbidity and mortality patterns of patients with asbestosis in New Zealand to determine (more fully) the overall health impact of past exposure to asbestos. METHODS: Individual mortality, cancer and hospital records for all New Zealand men diagnosed with asbestosis between 1974-2001 were examined. Mortality data were analysed for time trends, cause of death, and occupation. Trends for patients diagnosed with asbestosis were compared with those diagnosed with lung cancer. Hospital discharge data for men with asbestosis were examined to determine reasons for hospitalisation, resource utility, and recent hospitalisation trends. RESULTS: Death rates for New Zealand males dying with asbestosis increased between 1974-1999. Only 17% of deaths of males dying with asbestosis were directly attributed to this cause; the remainder were attributed to other non-malignant and malignant respiratory disease. Deaths from asbestos-related lung disease were grossly underestimated. Death certificates of men dying with asbestosis were found in all major occupational groups. Trends in hospital discharges may provide additional information for the overall modelling of the current epidemic of asbestos related disease. CONCLUSION: The number of men dying with asbestosis in NZ has increased in line with mesothelioma. There is some indication that asbestosis prevalence may have peaked for the most serious cases of asbestosis. Some level of asbestos exposure, as indicated by asbestosis, may be present in all major occupational groups.

Adult↗
PubMed1997

Radiographic asbestosis is not a prerequisite for asbestos-associated lung cancer in Ontario asbestos-cement workers.

In recent years, controversy has developed about whether pre-existing asbestosis is a prerequisite for the diagnosis of asbestos-related lung cancer. This paper presents the results of a prospective study, in a cohort of Ontario asbestos-cement workers, of lung cancer in relation to radiographs obtained 20 and 25 years from first exposure to asbestos. Radiographs were interpreted by a single NIOSH-certified "B" reader, and asbestosis was defined to mean an ILO code of 1/0 or greater. There were 143 subjects (123 without asbestosis, 20 with asbestosis), with a radiograph available for interpretation at 20 years from first exposure or later. The lung cancer standardized mortality ratio (SMR) among men without asbestosis at 20 years latency was 5.53 (95% CI: 2.9-9.7). There were 128 subjects (114 without asbestosis, 14 with asbestosis) with a radiograph available for interpretation at 25 years from first exposure or later. The lung cancer SMR among men without asbestosis at 25 years latency was 5.81 (95% CI 2.7-11). The results of this study are consistent with those of epidemiologic studies of asbestos-exposed populations in a variety of exposure situations. These studies have demonstrated that lung cancer risk is elevated in the presence of radiographic asbestosis, but they have also shown that lung cancer risk may be elevated in the absence of radiographic asbestosis.

Asbestos↗
PubMed1999

Carboxyterminal propeptide of type I procollagen in ELF: elevation in asbestosis, but not in pleural plaque disease.

Markers of collagen metabolism may possibly be used in the assessment of pulmonary involvement in asbestosis-related pulmonary diseases. In this study the levels of the carboxyterminal propeptide of type I procollagen (PICP) and the aminoterminal propeptide of type III procollagen (PIIINP) were evaluated in bronchoalveolar lavage fluid (BALF), epithelial lining fluid (ELF) and serum from patients with asbestos related pulmonary and pleural involvement. Forty-two consecutive patients with occupational exposure to asbestos fibres, who underwent bronchoscopy and bronchoalveolar lavage (BAL) at the time of the diagnosis were investigated. Five patients were diagnosed as having asbestosis, while 37 showed no parenchymal involvement. Of the latter group, 25 had pleural plaques, while 12 had no detectable changes in chest radiographs. The patients were followed-up for an average of 7 yrs. The PICP in BALF and ELF was detectable in all patients with asbestosis and in 8/37 subjects without parenchymal involvement. The levels of PICP in BALF and ELF were significantly higher in the asbestosis group compared to the patients without asbestosis (9.8+/-1.8 microg x L(-1) versus 0.6+/-1.3 microg x L(-1), p<0.001 and 488.9+/-208.8 microg x L(-1) versus 22.6+/-50.6 microg x L(-1), p<0.001, respectively). Only 1 patient with asbestosis and 3 patients without parenchymal involvement had detectable levels of PIIINP in BALF. The serum levels of PICP and PIIINP did not differ between the patients with asbestosis and those with exposure to asbestos fibres without asbestosis and were within the normal range. None of the 37 patients exposed to asbestos fibres without parenchymal involvement at the baseline developed asbestosis during the follow-up period of 7 yrs. In conclusion, the data show that the carboxyterminal propeptide of procollagen type I, but not the aminoterminal propeptide of type III procollagen is highly elevated in bronchoalveolar lavage fluid and epithelial lining fluid in patients with asbestosis, but not in those without parenchymal involvement. This suggests that the determination of carboxyterminal propeptide of procollagen type I in bronchoalveolar lavage fluid could be used as a marker of parenchymal involvement in patients exposed to asbestos fibres.

Asbestos↗
PubMed2003

The clinical diagnosis of asbestosis in this century requires more than a chest radiograph.

Asbestosis can cause significant impairment and even death. It is also a well-recognized risk factor for the development of lung cancer. However, asbestosis is usually diagnosed on clinical grounds without the aid of pathology. Many physicians and researchers believe that in asbestos-exposed individuals with adequate latency, chest radiographic findings that are compatible with asbestosis are sufficient for the diagnosis. In order to determine whether this approach is reasonable, the positive predictive value of the chest radiograph for the diagnosis of pathologic asbestosis must be determined. This requires information about the prevalence of asbestosis, and the sensitivity and specificity of the chest radiograph in its diagnosis. In this article, the sensitivity and specificity of the chest radiograph in diagnosing asbestosis is determined from a literature analysis. The prevalence of asbestosis among present-day cohorts, such as construction workers and petrochemical workers, is assessed based on the relative risk of lung cancer in patients with asbestosis and the overall relative risk of lung cancer in these occupationally asbestos-exposed cohorts. The results indicate a positive predictive value for abnormal chest radiograph findings alone to be significantly < 50%. Therefore, the chest radiograph is inadequate as the sole clinical tool to be used to diagnose asbestosis in these cohorts. However, when rales and a low diffusing capacity of the lung for carbon monoxide are also present, the diagnosis of asbestosis on clinical grounds can be made with reasonable confidence.

Asbestosis↗
PubMed1990

Does asbestosis increase the risk of lung cancer?

The question of whether asbestos workers with or without asbestosis have the same risk of lung cancer has not been adequately addressed in the literature. Studies of asbestos workers indicate that clinical symptoms and abnormal lung X-rays are more frequent among smokers than non-smokers, and some studies show that workers with asbestosis compared to those without asbestosis are more likely to be smokers or ex-smokers. Since smoking has a large affect on the risks of lung cancer, smoking habits should be considered when evaluating the risk of lung cancer among persons with and without asbestosis. Some studies show that the risk of lung cancer is higher for persons with asbestosis compared to persons without asbestosis, but none of these studies also considered the combined effects of smoking and asbestos exposure on the risk of lung cancer. It is unlikely that the higher risk of lung cancer to persons with asbestosis is only due to their higher prevalence of smoking. Some studies have suggested that asbestos workers with asbestosis may have a higher risk of lung cancer, but no definite conclusions can be drawn since dose-response relations were not evaluated. Further studies are needed to evaluate the interrelationships of smoking, asbestosis and the risk of lung cancer.

Asbestosis↗
PubMed1988

A clinical diagnostic model for the assessment of asbestosis: a new algorithmic approach.

Asbestosis, one of the pneumoconioses that is defined by a set of clinical, radiographic, and pathologic findings, occurs as a result of exposure to asbestos fibers. Several approaches have attempted to describe the presence, progression, or extent of asbestosis. However, these approaches have attempted to describe the presence, progression, or extent of asbestosis. However, these approaches have limitations or lack correlations with other diagnostic modalities. We propose a comprehensive clinical diagnostic model that uses the sensitivities and specificities of the various clinical, radiographic, and pathologic findings to generate a set of "likelihood numbers." These likelihood numbers, contribute to the calculation of a value that can indicate the probability of asbestosis. The clinical diagnostic model is heuristic in that a specific feature supportive of the diagnosis of asbestosis may be tested as to its sensitivity and specificity, and new features may be added to the model. The model also indicates how probabilistic a given set of findings is in the diagnosis of asbestosis and suggests what additional data may make the diagnosis more or less statistically probable. Regarding the radiologic considerations of asbestosis, the strength of the clinical diagnostic model is that it is capable of supporting a diagnosis of asbestosis in the presence of a normal chest radiograph and, conversely, may reject the diagnosis of asbestosis despite the radiographic finding of pulmonary fibrosis.

Algorithms↗
PubMed1992

High resolution computed tomographic assessment of asbestosis and cryptogenic fibrosing alveolitis: a comparative study.

BACKGROUND: The aim of this study was to compare the distribution and configuration of lung opacities in patients with cryptogenic fibrosing alveolitis and asbestosis by high resolution computed tomography. METHODS: Eighteen patients with cryptogenic fibrosing alveolitis and 24 with asbestosis were studied. Two independent observers assessed the type and distributions of opacities in the upper, middle, and lower zones of the computed tomogram. RESULTS: Upper zone fibrosis occurred in 10 of the 18 patients with cryptogenic fibrosing alveolitis and in six of the 24 patients with asbestosis. A specific pattern in which fibrosis was distributed posteriorly in the lower zones, laterally in the middle zones, and anteriorly in the upper zones was seen in 11 patients with cryptogenic fibrosing alveolitis and in four with asbestosis. Band like intrapulmonary opacities, often merging with the pleura, were seen in 19 patients with asbestosis but in only two with cryptogenic fibrosing alveolitis. Areas with a reticular pattern and a confluent or ground glass pattern were the commonest features of cryptogenic fibrosing alveolitis (15 and 14 patients respectively) but were uncommon in asbestosis (four and three patients). Pleural thickening or plaques were seen in 21 patients with asbestosis and in none with cryptogenic fibrosing alveolitis. CONCLUSION: Apart from showing pleural disease high resolution computed tomography showed that confluent (ground glass) opacities are common in cryptogenic fibrosing alveolitis and rare in asbestosis whereas thick, band like opacities are common in asbestosis and rare in cryptogenic fibrosing alveolitis.

Adult↗
PubMed2003

High-resolution CT of asbestosis and idiopathic pulmonary fibrosis.

OBJECTIVE: We studied high-resolution CT of asbestosis and idiopathic pulmonary fibrosis to determine whether differences-other than the frequency of associated pleural changes-could be discerned between the two diseases. MATERIALS AND METHODS: High-resolution CT scans of 80 patients with asbestosis and 80 patients with idiopathic pulmonary fibrosis were retrospectively reviewed. Two chest radiologists assessed the type and distribution of parenchymal and pleural abnormalities on high-resolution CT. RESULTS: Subpleural dotlike or branching opacities (65/80), subpleural curvilinear lines (55/80), mosaic perfusion (39/80), and parenchymal bands (38/80) were more common in patients with asbestosis (p < 0.0001). Visible intralobular bronchioles (62/80), bronchiolectasis within fibrotic consolidations (47/80), and honeycombing (61/80) were more common in patients with idiopathic pulmonary fibrosis (p < 0.0001). The frequencies of interlobular septal thickening, ground-glass opacities, fibrotic consolidation, and emphysema were similar in both groups. Parenchymal bands and fibrotic consolidation were more commonly seen (p < 0. 05) in patients with asbestosis associated with pleural disease (n = 66) than in patients with asbestosis without pleural disease (n = 14). Also, statistically significant differences were noted between high-resolution CT findings of patients with asbestosis without pleural disease and those of patients with idiopathic pulmonary fibrosis, except for parenchymal bands. CONCLUSION: Specific combinations of high-resolution CT findings strongly suggest either asbestosis or idiopathic pulmonary fibrosis. We found that CT findings that might have represented bronchiolar obstruction in the subpleural region were more prominent in patients with asbestosis than in those with idiopathic pulmonary fibrosis, whereas bronchiolar dilatation was more prominent in patients with idiopathic pulmonary fibrosis than in those with asbestosis.

Asbestosis↗