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PubMed1986

Outcome of asbestos exposure (lung fibrosis and antinuclear antibodies) with respect to skin reactivity: an 8-year longitudinal study.

Two hundred seventy asbestos workers were examined during an 8-year period. During this time five consecutive surveys were completed. Skin tests with streptokinase-streptodornase (SK-SD), tuberculin (PPD), and phytohemagglutinin (PHA) were performed in the middle of this period. The results of these tests were related to X-ray chest film results and the appearance of antinuclear antibodies (ANA). In all surveys, except the first, X-ray films with small irregular opacities with a profusion greater than or equal to 1/1 belonged more frequently to asbestos workers who did not respond to SK-SD or PHA. Thirty-one cases of asbestosis were diagnosed at that time, 23 of them became asbestotic after the skin tests were performed. Asbestotic cases contributed more frequently to the group with anergy as compared to asbestos workers lacking asbestosis. Furthermore, asbestosis was correlated with lack of response to second strength of SK-SD in males and PHA in both sexes. Lack of response to these activators was predictive of asbestosis. Asbestos workers with ANA frequently displayed a lack of response to the first strength of SK-SD, PPD, and PHA. This was partly due to the presence of asbestotic cases in the group. However, low responders to all these activators were found more frequently in the group with ANA independent of the presence of asbestosis.

Adult↗
PubMed1990

Airway obstruction in asbestos-exposed shipyard workers: with and without irregular opacities.

Airway obstruction was measured by spirometry in 296 boilermakers with 15 or more years shipyard exposure to asbestos. Percent of predicted was used to adjust each worker's pulmonary function values for height (mean 174 cm), age (mean 52.5 years) and cigarette smoking (mean 23.3 years). Mean values were significantly (P less than 0.05) below predicted for FVC 4.23 l 94.2% FEV1 3.06 l 89.3%, FEF25-75 2.51 l sec-1 82.3% and FEF75-85 0.574 l sec-1 77.8%. Corresponding values for the 106 men with pulmonary asbestosis (ILO profusion of opacities 1/0 or greater), were below these levels. Those without radiographic signs of asbestosis had intermediate values significantly below predicted. Correlation coefficients for pulmonary functions with ILO categories of asbestosis (profusion of irregular opacities) were: FVC -0.2381, FEV1 -0.2494, FEF25-75 -0.2403 and FEF75-85 -0.1629. All were significant P less than 0.05. The subgroup with radiographic asbestosis (ILO 1/0 or greater), had more functional loss. Data on this large cohort of asbestos-exposed workers establish that airway obstruction occurs after 15 years of exposure and before the slightest profusion of asbestosis scarring in the lungs of shipyard workers, and worsens progressively with greater profusions of irregular opacities.

Airway Obstruction↗
PubMed1999

Incidence of cancer among Finnish patients with asbestos-related pulmonary or pleural fibrosis.

OBJECTIVES: To study the asbestos-associated risk of lung cancer according to the histological type of cancer, the time of and time since diagnosis of asbestosis, the asbestos-associated risk for cancers other than lung cancer or mesothelioma, and the predictive value of asbestos-related pleural abnormalities as regards the risk of cancer. METHODS: Finnish patients with asbestosis (n = 1,376) or asbestos-related benign pleural disease (n = 4,887) notified as an occupational disease since 1964 were followed-up through the Finnish Cancer Registry for cancer in 1967-95. RESULTS: Compared with the total cancer incidence in Finland, men with asbestosis had a raised risk of lung cancer (standardized incidence ratio [SIR] = 6.7; 95% confidence interval [CI] = 5.6-7.9), mesothelioma (SIR = 32, CI = 14-60) and cancer of the larynx (SIR = 4.2, CI = 1.4-9.8). The risk of lung cancer was similarly raised for all histological types of lung cancer (the highest in insulators) and did not change markedly over time of notification or duration of follow-up. Men with benign pleural disease had a raised risk of mesothelioma (SIR = 5.5, CI = 1.5-14) and a slightly elevated risk of lung cancer (SIR = 1.3, CI = 1.0-1.8). Among women with asbestosis, significant excess was found for lung cancer and mesothelioma. CONCLUSION: Asbestosis and asbestos-related benign pleural disease seem to possess different predictive values as regards the risk of lung cancer.

Adult↗
PubMed1985

Lymphocyte subpopulations in bronchoalveolar lavage fluid in asbestos workers.

We examined peripheral blood and bronchoalveolar lavage (BAL) fluid lymphocyte subpopulations in 29 asbestos workers, 10 with and 19 without clinical or radiologic evidence of asbestosis. Peripheral blood lymphocyte subpopulations were also measured in 13 control subjects. The mean OKT4:OKT8 (T-helper/inducer:T-suppressor/cytotoxic lymphocyte) ratio in BAL fluid in the 29 asbestos workers was 0.96 (range, not detected to 3.33), significantly less than 1.76 (1.33 to 2.67) in peripheral blood (p less than 0.001). There were no significant differences in OKT4:OKT8 ratios in peripheral blood between the 10 patients with asbestosis, the 19 asbestos workers without asbestosis, and the 13 normal control subjects or in the OKT4:OKT8 ratios in BAL fluid between patients with asbestosis and asbestos workers without asbestosis. In the group as a whole, 83% of those who had suffered more than 5 yr of exposure to asbestos showed OKT4:OKT8 ratios less than 1.2, whereas in those who had suffered fewer than 5 yr of exposure, 80% showed ratios greater than 1.2 (p less than 0.02). No other relationships between OKT4:OKT8 ratios and clinical, radiographic, or physiologic variables were observed.

Adult↗
PubMed1990

Human disease consequences of fiber exposures: a review of human lung pathology and fiber burden data.

Inhalation of asbestos fibers results in a variety of neoplastic and nonneoplastic diseases of the respiratory tract. Some of these diseases, such as asbestosis, generally occur after prolonged and intensive exposure to asbestos, whereas others, such as pleural mesothelioma, may occur following brief exposures. Inhalation of nonasbestiform mineral fibers can occur as well, and these fibers can be recovered from human lung tissue. Thus, there has been considerable interest in the relationship between mineral fiber content of the lung and various pathologic changes. Techniques for fiber analysis of human tissues have not been standardized, and consequently results may differ appreciably from one laboratory to another. In all reported series, extremely high fiber burdens are found in the lungs of individuals with asbestosis. Although there is a correlation between the tissue concentration of asbestos fibers and the severity of pulmonary fibrosis, further studies of the mineralogic correlates of fiber-induced pulmonary fibrosis are needed. Mesothelioma may occur with fiber burdens considerably less than those necessary to produce asbestosis. More information is needed regarding the migration of fibers to the pleura and the numbers, types, and dimensions of fibers that accumulate at that site. Patients with asbestosis have a markedly increased risk for lung cancer, but the risk of lung cancer attributable to asbestos in exposed workers without asbestosis who also smoke is controversial. Combined epidemiologic-mineralogic studies of a well-defined cohort are needed to resolve this issue. In addition, more information is needed regarding the potential role of nonasbestos mineral fibers in the pathogenesis of lung cancer.

Asbestos↗
PubMed2000

Asbestos content of lung tissue and carcinoma of the lung: a clinicopathologic correlation and mineral fiber analysis of 234 cases.

The aim of this study was to investigate the asbestos content of lung tissue in a series of patients with lung cancer and some history of asbestos exposure. This information was then correlated with demographic information, occupational and smoking history, presence or absence of pathologic asbestosis or pleural plaques, and pathologic features of the cancer. The pulmonary concentration of asbestos fibers in 234 cases of primary carcinoma of the lung was determined by means of a tissue digestion technique. Asbestos body counts were performed in 229 cases and fiber analysis by scanning electron microscopy in 221 cases. Asbestos content was recorded as total asbestos fibers, commercial amphibole fibers, noncommercial amphibole fibers, and chrysotile fibers 5 microm or greater in length per gram of wet lung tissue. The study group included 70 patients with asbestosis (Group I), 44 patients with parietal pleural plaques but without asbestosis (Group II), and 120 patients with neither (Group III). The median asbestos body content of Group I was more than 35 times greater than Group II and more than 300 times greater than Group III. The total asbestos fiber count for Group I was nearly 20 times greater than Group II and more than 50 times greater than Group III. The difference was due almost entirely to commercial amphiboles. In a series of primary lung cancer cases with some history of asbestos exposure, a markedly elevated asbestos content was identified among those with pathologic asbestosis as compared with patients with pleural plaques alone or with neither plaques nor asbestosis.

Aged↗
PubMed2004

[Apoptosis of bronchoalveolar lavage lymphocytes (L-BAL) in pneumoconiosis].

BACKGROUND: The appearance and extension of apoptosis phenomenon in lymphocytes originated from the lower airways of patients with pneumoconioses, including silicosis and asbestosis, as well as its relation to the clinical data, remains unclear. METHODS: Bronchoalveolar lavage (BAL) was carried out in 11 patients with silicosis, 8 with asbestosis and in 7 control subjects. L-BAL were a) studied for CD95 and CD95 Ligand expression, b) permeabilized and stained with PI (flow cytometry, ModFit software) for apoptosis/cell cycle analyses and c) stained with Annexin V FITC/PI. RESULTS: The low number of L-BAL enter apoptosis. No significant changes between studied groups were found in PI determined apoptosis (silicosis: 1.8 +/- 0.7%, asbestosis: 3.1 +/- 0.9%, controls: 1 +/- 0.7%, median +/- SEM). Similar results were obtained, if tested with Annexin V FITC. However, the asbestosis group was characterized by higher CD4/CD8 ratio and increased percent of L-BAL CD95 Ligand expression (21.0 +/- 4.5 vs 13.7 +/- 3.3 in controls). In silicosis L-BAL apoptosis was inversely correlated with FEV1/VC values (r=-0.26, p<0.05). Surprisingly the majority of BAL lymphocytes expressed CD95, the marker of cell susceptibility to apoptotic stimuli; no difference between studied groups was found. CONCLUSIONS: Lower airways lymphocytes seem to be prevented from excessive apoptosis. Tendency to slightly increased percent of apoptotic and/or Fas Ligand cells reflects likely the local immunity alterations in asbestosis patients.

Adult↗
PubMedDate not supplied

Diagnosis of asbestos-related pleuropolmonary diseases.

A revision of criteria for diagnosis of asbestos-related pathological conditions was performed studying specially asbestosis, pleural plaques and malignant mesothelioma, also taking into account the problems connected with histopathology. As regards the histological diagnosis of asbestosis, it requires the presence of diffuse interstitialfibrosis in a well inflated tissue remote from the site of a tumour or other large lesion, plus the presence of two or more asbestos bodies in a 1 cm2 section. As regards the imaging diagnosis, the HRTC 4-point scale proposed by Paris et al. (2004) has been adopted:--0 images not suggestive of interstitial pneumonia;--1 modest unilateral or bilateral interstitial abnormalities, involving restricted areas if bilateral;--2 interstitial abnormalities of limited extent, but consistent with a diagnosis of asbestosis, i.e. honeycombing, even without other parenchymal changes and even though unilateral, or else any two abnormal findings among thickened interlobular septa, intralobular lines or subpleural curved lines;--3 numerous bilateral changes on several slices involving more than 2/3 of the posterior third of each hemi thorax. Only points 2 and 3 were considered consistent with the diagnosis of lung fibrosis. Such HRCT findings are not specific for asbestosis, changes in the pleural wall such as diffuse plaques and thickenings contribute to the diagnosis of asbestosis. As regards the pleural plaques and asbestos bodies we remark that they are merely exposition markers. We also discussed the problems the pathologist may encounter in diagnosing mesothelioma; in this field the prospects are encouraging as microarray analysis are beginning to identify new molecular markers for mesothelioma.

Asbestos↗
PubMed1991

Scanning electron microscopic analysis of mineral fiber content of lung tissue in the evaluation of diffuse pulmonary fibrosis.

The mineral fiber content of lung parenchyma in 24 cases of diffuse pulmonary fibrosis of unknown cause was determined by scanning electron microscopy and compared with that of 36 autopsy cases of histologically confirmed asbestosis and 20 autopsy cases of patients with normal lungs. Fibers were isolated from the lung using a hypochlorite digestion technique and collected on the surface of a polycarbonate filter. In addition, the types of fibers present (asbestos vs. other mineral fibers) were determined by energy dispersive x-ray analysis (EDXA). When the histologic grade of fibrosis in the cases of asbestosis was compared with the uncoated fiber content by means of linear regression analysis, it was determined that the fiber content of the 24 cases of diffuse pulmonary fibrosis of unknown cause was below the 95% confidence limit for asbestosis in every instance. Furthermore, the majority of fibers analyzed by EDXA were not asbestos in the cases with diffuse pulmonary fibrosis of unknown cause, whereas more than 90% of the fibers from the asbestosis cases were commercial amphiboles (amosite or crocidolite). It was concluded that most patients with advanced pulmonary fibrosis whose tissue samples do not meet histologic criteria for asbestosis do not have asbestos-induced fibrosis, even though there may be some history of exposure to asbestos. In such cases, scanning electron microscopic analysis of mineral fiber content and EDXA of the types of fibers present often provide useful information with regard to the correct classification of these cases.

Adult↗
PubMedDate not supplied

Asbestos and cancer in Finland.

Cancer mortality of men with diagnosed asbestosis was studied in Finland. Of the 174 men registered as having asbestosis, 56 had died before 1977, whereas the number of expected deaths based on the Finnish male population was only 23.4. The respective figures for lung cancer were 19 observed and 2.1 expected. The mean age of these 19 lung cancer patients was 57.8 yr, and lung cancer was the cause of death (underlying cause) in 35% of all diseased men with asbestosis. The proportion of lung cancer mortality from all deaths among Finnish men 55-64 yr old is 10.8%, which is clearly lower than that among the men with asbestosis. No excess of other malignancies was found in Finland among workers with asbestosis.

Asbestos↗
PubMed1986

Correlation between fibre content of the lungs and disease in naval dockyard workers.

In the period 1966-82 lungs from 333 workers who had been employed at a Royal Naval dockyard were referred to the MRC Pneumoconiosis Unit where they were investigated for the severity of asbestosis, the presence of tumours, and an assessment of mineral fibre content and the type and amount of mineral present. The occupational exposure to mineral dust has been coded for 189 of these cases. There is good correlation between the severity of asbestosis and the coded exposures, electron microscopic mineral fibre count, and the fibre count as seen under the light microscope. The information collected showed that mesotheliomas occurred in those who had had minimal or slight asbestosis, by contrast with the pulmonary carcinomas found in those with moderate to severe asbestosis. The amphibole (crocidolite and amosite) lung content correlated with severity of asbestosis.

Aged↗
PubMed2004

Concentration of hydroxyproline in blood: a biological marker in occupational exposure to asbestos and its relationship with Pi*Z and Pi*S polymorphism in the alpha-1 antitrypsin gene.

BACKGROUND: Hydroxyproline (OHP) is one of the most abundant amino acids in collagen and, in general, it provides a good measure of overall collagen catabolism. METHODS: Asbestos workers suffering from asbestosis (cases n = 85); asbestos exposed workers without asbestosis (exposed controls, EC, n = 86), and non-exposed population (non-exposed controls, NEC, n = 122) were studied. The concentration of free OHP in whole blood was measured following the Pico-Tag procedure. RESULTS: Concentration of OHP in blood was significantly different in the three groups studied (P < 0.001), being higher in cases (19.8 +/- 14.7 micromol/L) than in EC (16 +/- 12.4) and NEC (13.5 +/- 6.7). When all individuals were grouped and stratified by the Pi*S and Pi*Z polymorphisms in the alpha-1-antitrypsin gene, the highest OHP levels were detected in the Pi*S homozygotes, one of the asbestosis-at risk-genotypes (Pi*S homozygotes, x = 24.5 +/- 11.7; Pi*S heterozygotes, x = 16.6 +/- 10.0; wild type, wt, x = 15.9 +/- 11.8). CONCLUSIONS: Blood OHP concentration could be used for monitoring human exposure to asbestos, either as a marker for occupational monitoring or as an additional clinical parameter in diagnostic exploration of asbestosis.

Alleles↗
PubMed1992

Hyaluronan (hyaluronic acid) in lung lavage of asbestos-exposed humans and sheep.

The concentration of hyaluronan was measured in the bronchoalveolar lavage fluid (BALF) of 18 control subjects and 27 workers from the asbestos mills and mines of Québec, 9 without asbestosis and 18 with asbestosis. Hyaluronan was also measured in the BALF of 9 control sheep exposed to 100 ml phosphate-buffered saline (PBS) at 10 day intervals for 39 months, and 13 sheep exposed at the same intervals to 100 mg chrysotile in 100 ml PBS for 24 months. At month 24, the asbestos-exposed sheep were classified into 3 groups: (A) 4 sheep exposed to PBS alone, (B) 4 sheep exposed to 10 mg chrysotile asbestos every 10 days, and (C) 5 sheep exposed to 100 mg chrysotile asbestos every 10 days for 15 months. The BALF hyaluronan averaged 53.9 +/- 7.4 ng/ml in human controls, 67.5 +/- 10.3 ng/ml in asbestos-exposed workers without asbestosis, and 206 +/- 83 ng/ml in workers with asbestosis (p less than 0.05 vs. normal). In the control sheep, BALF hyaluronan was 34.7 +/- 6.9 ng/ml, and it was 31.5 +/- 17.8 ng/ml in the low-dosage asbestos-exposed group (A), 83.0 +/- 27.7 ng/ml in the intermediate-dose group (B), and 248.0 +/- 134.7 ng/ml in the high-dosage group (C) (p less than 0.05 vs. controls). In contrast, the release of plasminogen activator, a protease that may play a role in limiting the fibrotic process, was increased in group A, but not in groups B and C. In conclusion, BALF hyaluronan constitutes an indicator of lung interstitial tissue changes that may reflect the activity of the fibrosing alveolitis associated with chronic asbestos exposure.

Adult↗
PubMed1992

The prevalence of enlarged mediastinal lymph nodes in asbestos-exposed individuals: a CT study.

Patients with cryptogenic fibrosing alveolitis have a higher prevalence of enlarged mediastinal lymph nodes compared with the normal population. To determine whether or not this observation applies to individuals with asbestos-induced pulmonary fibrosis the high resolution computed tomography (CT) scans of 14 patients with definite asbestosis and 11 age-matched cases with benign asbestos-induced pleural disease, but no lung disease, were re-imaged on soft tissue settings. The site, size and number of mediastinal lymph nodes equal to, or greater than, 1.2 cm were recorded. In the asbestosis group 14 out of 14 patients had at least one enlarged lymph node with an average number per individual of four (range 1-10). In the control group two out of 11 patients each had one minimally enlarged lymph node. We conclude that mediastinal lymph node enlargement occurs frequently in asbestosis: awareness of this is important in the investigation of malignant disease in patients with asbestosis.

Aged↗
PubMed1980

The follow-up study of skin reactivity to recall antigens and E- and EAC-RFC profiles in blood in asbestos workers.

We have determined cutaneous DTH reactions to SK-SD and PPD and peripheral blood lymphocyte profiles in a group of asbestos workers in two consecutive surveys. It was found that asbestosis and, to a lesser extent, the presence of ANA are significantly correlated with the lack of response to the above antigens. 83% of asbestos workers when tested at a 4 year interval fell into the same two categories of responsiveness (lack of response or response at least to one antigen). The asbestosis cases had lower total lymphocyte count as well as proportions and absolute number of E-RFC as compared to asbestos workers without asbestosis and/or ANA. Furthermore, the latter group showed the lower percentages and absolute number of E-RFC than the matched controls. The presence of ANA is also correlated with lower proportions of E-RFC. However, this is related at least in part to asbestosis.

Antibodies, Antinuclear↗
PubMed2003

Synchronous diffuse malignant mesothelioma and carcinomas in asbestos-exposed individuals.

AIMS: The development of synchronous diffuse malignant mesothelioma and carcinoma in individuals exposed to asbestos is rare. We report nine cases and discuss the medico-legal implications. METHODS AND RESULTS: Five hundred patients seeking compensation for asbestos-related diffuse malignant mesothelioma were reviewed with access to post-mortem data. The study group comprised cases in which a second (non-mesothelial) neoplasm was identified. The study group comprised eight males, one female, mean age 68 years (range 60-75). All individuals gave a history of asbestos exposure. Synchronous malignant mesothelioma with carcinoma was identified in 9/500 (1.8%). Eight malignant mesotheliomas were pleural, one was primary peritoneal in origin. By morphological subtyping there were four epithelioid, three biphasic and two sarcomatoid mesotheliomas. In 6/9 (67%) the second tumour was a primary bronchogenic carcinoma (three adenocarcinomas, two squamous cell carcinomas and one small-cell carcinoma). In 3/9 (33%) the second tumour was a non-bronchogenic carcinoma (colonic, pancreatic and breast ductal adenocarcinoma). No other neoplasms were identified in the cohort of malignant mesotheliomas studied. Five persons had pathological evidence of asbestosis (four had bronchogenic carcinomas, one colorectal adenocarcinoma). Two persons with non-bronchogenic carcinomas had identifiable asbestos bodies but no interstitial fibrosis. In two cases the second neoplasms (primary bronchogenic squamous cell and small-cell carcinomas) were associated with diffuse interstitial fibrosis but no asbestos bodies were seen on light microscopy. In each case transmission electron microscopic mineral analysis revealed an asbestos fibre burden within the background population range for control subjects and well below that seen in cases of established asbestosis. These cases were considered to represent cryptogenic fibrosing alveolitis in subjects with a history of asbestos exposure. CONCLUSIONS: Synchronous malignant mesothelioma with carcinomas in asbestos-exposed workers is rare and identified in 1.8% of 500 malignant mesotheliomas in this series. In most cases the carcinoma represents a primary bronchogenic neoplasm. Primary lung carcinomas are recognized to be asbestos related only when occurring in association with asbestosis. In this series this combination (bronchogenic carcinoma and asbestosis) was seen in four (0.8%) cases. In post-mortem cases for possible malignant mesothelioma it is important to identify any other neoplasia and determine whether it is related to asbestos. Their presence impact upon anticipated life expectancy and in the presence of malignant mesothelioma will affect the compensation settlement.

Adenocarcinoma↗
PubMedDate not supplied

Malignant mesothelioma in Japan: analysis of registered autopsy cases.

In the Annual of the Pathological Autopsy Cases in Japan, issued by the Japanese Society of Pathology from 1958 to 1996, a total of 1,846 (0.17%) malignant mesothelioma cases (1,287 male, 558 female, 1 unknown) were registered among 1,056,259 autopsy cases. The frequency of mesothelioma (number of cases/total autopsy cases) was 0.10% (461/440,334) for the term 1958-1979, 0.18% (716/390,124) for 1980-1989, and 0.30% (669/225,801) for 1990-1996; the frequency of cases increased significantly over the time periods (p < .0001). Among 1,785 cases for which tumor sites were ascertained, there were 1,213 pleural mesothelioma (68.0%), 431 peritoneal (24.1%), 108 pericardial (6.1%), 6 tunica vaginalis testis (0.3%), and 28 "others" (1.6%). Histological cell type was noted in 598 cases; 245 (41.0%) were epithelial, 168 (28.1%) were biphasic, and 185 (30.9%) were sarcomatous. Seventy-three (0.007%) cases of malignant mesothelioma with asbestosis were found during the entire 39-y period. The frequency of those with asbestosis (number of cases/total autopsy cases) was 0.001% (5/440,334) for the term 1958-1979, 0.006% (27/390,124) for 1980-1989, and 0.018% (41/225,801) for 1990-1996; this increase over time was statistically significant (p < .0001). Researchers expect that cases of asbestos-related mesothelioma will increase in Japan in the future. Tumor sites and histological cell types of mesothelioma with asbestosis did not differ from those in individuals without asbestosis.

Adolescent↗
PubMed1993

Radiographic abnormalities and mortality in subjects with exposure to crocidolite.

Plain chest radiographs from a one in six random sample of the workforce of the asbestos industry at Wittenoom, Western Australia between 1943 and 1966 have been classified for degree of profusion and pleural thickening by two independent observers according to the 1980 UICC-ILO Classification of Radiographs for the pneumoconioses to clarify the effect of degree of radiological abnormality on survival. A total of 1106 subjects were selected. Each subject's age, cumulative exposure to crocidolite, and time since first exposure were determined from employment records, the results of a survey of airborne concentrations of fibres > 5 mu in length conducted in 1966, and an exposure rating by an industrial hygienist and an ex-manager of the mine and mill at Wittenoom. By the end of 1986 193 subjects had died. Conditional logistic regression was used to model the relative risk of death in five separate case-control analyses in which the outcomes were deaths from: (1) all causes, (2) malignant mesothelioma, (3) lung cancer, (4) asbestosis, and (5) other causes excluding cancer and asbestosis. Up to 20 controls per case were randomly chosen from all men of the same age who were not known to have died before the date of death of the index case. After adjustment for exposure and time since first exposure, there were significant and independent effects of radiographic profusion and pleural thickening on all cause mortality. The effect of profusion was largely a result of the effect on mortality from malignant mesothelioma and asbestosis but not lung cancer. The effect of pleural thickening was greatest on mortality from other causes, mainly ischaemic heart disease. This study has shown that degree of radiographic abnormality has an independent effect on mortality from malignant mesothelioma, asbestosis, and all causes even after allowing for the effects of age, degree of exposure, and time since first exposure.

Asbestos, Crocidolite↗