Inter-reader agreement in HRCT detection of pleural plaques and asbestosis in participants with previous occupational exposure to asbestos.

OBJECTIVES: To investigate inter-reader agreement for the detection of pleural and parenchymal abnormalities using CT in a large cross-sectional study comprising information on individual cumulative exposure to asbestos. METHODS: The project was approved by the hospital ethics committee, and all patients received information on the study and gave their written informed consent. In 5511 CT scans performed in a cohort of retired workers previously exposed to asbestos and volunteering to participate in a multiregional survey programme (Asbestos Related Diseases Cohort, ARDCO), double randomised standardised readings, triple in case of disagreement, were performed by seven trained expert radiologists specialised in thoracic imaging and blind to the initial interpretation. Inter-reader agreement was evaluated by calculating the κ-weighted coefficient between pairs of expert readers and results of routine practice and final diagnosis after expert reading. RESULTS: κ-Weighted coefficients between trained experts ranged from 0.28 to 0.52 (fair to good), 0.59 to 0.86 (good to excellent) and 0.11 to 0.66 (poor to good) for the diagnosis of asbestosis, pleural plaques and fibrosis of the visceral pleura, respectively. κ-Weighted coefficients between results of routine practice and final diagnosis after expert reading were 0.13 (poor), 0.53 (moderate) and 0.11 (poor) for the diagnosis of asbestosis, pleural plaques and fibrosis of the visceral pleura, respectively. CONCLUSIONS: Interpretation of benign asbestos-related thoracic abnormalities requires standardisation of the reading and trained readers, particularly for participants asking for compensation, and with a view to the longitudinal survey of asbestos-exposed workers.

Differential mutation profiles and similar intronic TP53 polymorphisms in asbestos-related lung cancer and pleural mesothelioma.

Given the interest in defining biomarkers of asbestos exposure and to provide insights into asbestos-related and cell-specific mechanisms of neoplasia, the identification of gene alterations in asbestos-related cancers can help to a better understanding of exposure risk. To understand the aetiology of asbestos-induced malignancies and to increase our knowledge of mesothelial carcinogenesis, we compared genetic alterations in relevant cancer genes between lung cancer, induced by asbestos and tobacco smoke, and malignant pleural mesothelioma (MPM), a cancer related to asbestos, but not to tobacco smoke. TP53, KRAS, EGFR and NF2 gene alteration analyses were performed in 100 non-small cell lung cancer (NSCLC) patients, 50 asbestos-exposed and 50 unexposed patients, matched for age, gender, histology and smoking habits. Detailed assessment of asbestos exposure was based on both specific questionnaires and asbestos body quantification in lung tissue. Genetic analyses were also performed in 34 MPM patients. TP53, EGFR and KRAS mutations were found in NSCLC with no link with asbestos exposure. NF2 was only altered in MPM. Significant enhancement of TP53 G:C to T:A transversions was found in NSCLC from asbestos-exposed patients when compared with unexposed patients (P = 0.037). Interestingly, TP53 polymorphisms in intron 7 (rs12947788 and rs12951053) were more frequently identified in asbestos-exposed NSCLC (P = 0.046) and MPM patients than in unexposed patients (P < 0.001 and P = 0.012, respectively). These results emphasise distinct genetic alterations between asbestos-related thoracic tumours, but identify common potential susceptibility factors, i.e. single nucleotide polymorphisms in intron 7 of TP53. While genetic changes in NSCLC are dominated by the effects of tobacco smoke, the increase of transversions in TP53 gene is consistent with a synergistic effect of asbestos. These results may help to define cell-dependent mechanisms of action of asbestos and identify susceptibility factors to asbestos.

Pleural plaques and the risk of pleural mesothelioma.

BACKGROUND: The association between pleural plaques and pleural mesothelioma remains controversial. The present study was designed to examine the association between pleural plaques on computed tomography (CT) scan and the risk of pleural mesothelioma in a follow-up study of asbestos-exposed workers. METHODS: Retired or unemployed workers previously occupationally exposed to asbestos were invited to participate in a screening program for asbestos-related diseases, including CT scan, organized between October 2003 and December 2005 in four regions in France. Randomized, independent, double reading of CT scans by a panel of seven chest radiologists focused on benign asbestos-related abnormalities. A 7-year follow-up study was conducted in the 5287 male subjects for whom chest CT scan was available. Annual determination of the number of subjects eligible for free medical care because of pleural mesothelioma was carried out. Diagnosis certification was obtained from the French mesothelioma panel of pathologists. Survival regression based on the Cox model was used to estimate the risk of pleural mesothelioma associated with pleural plaques, with age as the main time variable and time-varying exposure variables, namely duration of exposure, time since first exposure, and cumulative exposure index to asbestos. All statistical tests were two-sided. RESULTS: A total of 17 incident cases of pleural mesothelioma were diagnosed. A statistically significant association was observed between mesothelioma and pleural plaques (unadjusted hazard ratio (HR) = 8.9, 95% confidence interval [CI] = 3.0 to 26.5; adjusted HR = 6.8, 95% CI = 2.2 to 21.4 after adjustment for time since first exposure and cumulative exposure index to asbestos). CONCLUSION: The presence of pleural plaques may be an independent risk factor for pleural mesothelioma.

Nuclear morphology for the detection of alterations in bronchial cells from lung cancer: an attempt to improve sensitivity and specificity.

OBJECTIVE: To identify which morphologic or densitometric parameters are modified in cell nuclei from bronchopulmonary cancer based on 18 parameters involving shape, intensity, chromatin, texture, and DNA content and develop a bronchopulmonary cancer screening method relying on analysis of sputum sample cell nuclei. STUDY DESIGN: A total of 25 sputum samples from controls and 22 bronchial aspiration samples from patients presenting with bronchopulmonary cancer who were professionally exposed to cancer were used. After Feulgen staining, 18 morphologic and DNA content parameters were measured on cell nuclei, via image cytom- etry. A method was developed for analyzing distribution quantiles, compared with simply interpreting mean values, to characterize morphologic modifications in cell nuclei. RESULTS: Distribution analysis of parameters enabled us to distinguish 13 of 18 parameters that demonstrated significant differences between controls and cancer cases. These parameters, used alone, enabled us to distinguish two population types, with both sensitivity and specificity > 70%. Three parameters offered 100% sensitivity and specificity. When mean values offered high sensitivity and specificity, comparable or higher sensitivity and specificity values were observed for at least one of the corresponding quantiles. CONCLUSION: Analysis of modification in morphologic parameters via distribution analysis proved promising for screening bronchopulmonary cancer from sputum.

Do asbestos-related pleural plaques on HRCT scans cause restrictive impairment in the absence of pulmonary fibrosis?

BACKGROUND: It is uncertain whether isolated pleural plaques cause functional impairment. OBJECTIVE: To analyse the relationship between isolated pleural plaques confirmed by CT scanning and lung function in subjects with occupational exposure to asbestos. METHODS: The study population consisted of 2743 subjects presenting with no parenchymal interstitial abnormalities on the high-resolution CT (HRCT) scan. Asbestos exposure was evaluated by calculation of an individual cumulative exposure index (CEI). Each subject underwent pulmonary function tests (PFTs) and HRCT scanning. Variables were adjusted for age, smoking status, body mass index, CEI to asbestos and the centres in which the pulmonary function tests were conducted. RESULTS: All functional parameters studied were within normal limits for subjects presenting with isolated pleural plaques and for those presenting with no pleuropulmonary abnormalities. However, isolated parietal and/or diaphragmatic pleural plaques were associated with a significant decrease in total lung capacity (TLC) (98.1% predicted in subjects with pleural plaques vs. 101.2% in subjects free of plaques, p=0.0494), forced vital capacity (FVC) (96.6% vs. 100.4%, p<0.001) and forced expiratory volume in 1 s (FEV(1)) (97.9% vs. 101.9%, p=0.0032). In contrast, no significant relationship was observed between pleural plaques and FEV1/FVC ratio, forced expiratory flow at 25-75% FVC and residual volume. A significant correlation was found between the extent of pleural plaques and the reduction in FVC and TLC, whereas plaque thickness was not related to functional impairment. CONCLUSIONS: The results show a relationship between isolated parietal and/or diaphragmatic pleural plaques and a trend towards a restrictive pattern, although the observed decrease in FVC and TLC is unlikely to be of real clinical relevance for the majority of subjects in this series.

Cancer incidence within a cohort occupationally exposed to asbestos: a study of dose--response relationships.

OBJECTIVES: The aim of our study was to analyse the dose-response relationship between occupational asbestos exposure and risk of cancer. METHODS: Our study was a retrospective morbidity study based on 2024 subjects occupationally exposed to asbestos, conducted over the period 1 January 1978 to 31 December 2004. Analysis of the dose-response relationship between occupational asbestos exposure, as a time-dependant variable, and risk of cancer was performed using a Cox model. In order to account for the effect of latency, we conducted the analysis with a lag of 10 years. RESULTS: 285 cases of cancers were observed in our cohort. The relative risk of pleuro-peritoneal mesothelioma, lung cancer and colorectal cancer associated with asbestos exposure, adjusted for age as a time-dependant variable and for sex, was correlated with exposure intensity (or average exposure level, AEL). The risk of cancer, whatever the anatomical site, did not increase with the duration of exposure to asbestos. CONCLUSION: While confirming the established relationship between asbestos exposure and pleuropulmonary and peritoneal cancers, this study also suggests a causal relationship between asbestos exposure and colorectal cancer.

CT scan screening is associated with increased distress among subjects of the APExS.

BACKGROUND: The aim of this study was to assess the psychological consequences of HRCT scan screening in retired asbestos-exposed workers. METHODS: A HRCT-scan screening program for asbestos-related diseases was carried out in four regions of France. At baseline (T1), subjects filled in self-administered occupational questionnaires. In two of the regions, subjects also received a validated psychological scale, namely the psychological consequences questionnaire (PCQ). The physician was required to provide the subject with the results of the HRCT scan at a final visit. A second assessment of psychological consequences was performed 6 months after the HRCT-scan examination (T2). PCQ scores were compared quantitatively (t-test, general linear model) and qualitatively (chi²-test, logistic regression) to screening results. Multivariate analyses were adjusted for gender, age, smoking, asbestos exposure and counseling. RESULTS: Among the 832 subjects included in this psychological impact study, HRCT-scan screening was associated with a significant increase of the psychological score 6 months after the examination relative to baseline values (8.31 to 10.08, p < 0.0001, t-test). This increase concerned patients with an abnormal HRCT-scan result, regardless of the abnormalities, but also patients with normal HRCT-scans after adjustment for age, gender, smoking status, asbestos exposure and counseling visit. The greatest increase was observed for pleural plaques (+3.60; 95%CI [+2.15;+5.06]), which are benign lesions. Detection of isolated pulmonary nodules was also associated with a less marked but nevertheless significant increase of distress (+1.88; 95%CI [+0.34;+3.42]). However, analyses based on logistic regressions only showed a close to significant increase of the proportion of subjects with abnormal PCQ scores at T2 for patients with asbestosis (OR = 1.92; 95%CI [0.97-3.81]) or with two or more diseases (OR = 2.04; 95%CI [0.95-4.37]). CONCLUSION: This study suggests that HRCT-scan screening may be associated with increased distress in asbestos-exposed subjects. If confirmed, these results may have consequences for HRCT-scan screening recommendations.

Does asbestos exposure cause airway obstruction, in the absence of confirmed asbestosis?

RATIONALE: Whether occupational exposure to asbestos causes airway obstruction remains controversial. OBJECTIVES: This study evaluated lung function in relation to cumulative exposure to asbestos in a large cohort of retired or unemployed workers exposed to asbestos. METHODS: The study population consisted of 3,660 volunteer subjects. An individual cumulative exposure index to asbestos was calculated for each subject, and information was obtained on smoking status. Pulmonary function tests were performed in all subjects; high-resolution chest computed tomography was also performed in 3,335 subjects. MEASUREMENTS AND MAIN RESULTS: Values of FEV(1)/FVC and FEF(25-75%) did not differ between five classes (quintiles) of cumulative exposure to asbestos, and no significant correlation was observed between cumulative exposure to asbestos and pulmonary function parameters, after adjustment for sex, tobacco consumption, emphysema, and body mass index. Furthermore, the proportion of abnormal pulmonary function tests did not differ between the five classes of cumulative exposure to asbestos. CONCLUSIONS: The results do not support a causal relationship between asbestos exposure alone and airway obstruction. However, the study sample may not be representative of all people occupationally exposed to asbestos, because a fraction of subjects with previously diagnosed asbestosis probably did not participate in this screening program.

p16INK4A inactivation mechanisms in non-small-cell lung cancer patients occupationally exposed to asbestos.

Epidemiological studies have shown that asbestos fibers constitute the major occupational risk factor and that asbestos acts synergistically with tobacco smoking to induce lung cancer. Although some somatic gene alterations in lung cancer have been linked to tobacco smoke, few data are available on the role of asbestos fibers. P16/CDKN2A is an important tumor suppressor gene that is frequently altered in lung cancer via promoter 5'-CpG island hypermethylation and homozygous deletion, and rarely via point mutation. Many studies suggest that tobacco smoking produces P16/CDKN2A promoter hypermethylation in lung cancer, but the status of this gene in relation to asbestos exposure has yet to be determined. The purpose of this study was to investigate the mechanism of P16/CDKN2A alterations in lung cancer in asbestos-exposed patients. P16/CDKN2A gene status was studied in 75 human non-small-cell lung cancer (NSCLC) cases with well-defined smoking habits, and detailed assessment of asbestos exposure, based on occupational questionnaire and determination of asbestos bodies in lung tissue. The results of this study confirm published data on the effect of tobacco smoke on P16/CDKN2A gene alterations, characterized by significantly higher P16/CDKN2A promoter hypermethylation in heavy smokers (more than 40 pack-years (P-Y)) than in smokers of less than 40 P-Y. These results also demonstrate a higher incidence of loss of heterozygosity and homozygous deletion in asbestos-exposed cases, after adjustment for age and cumulative tobacco consumption, than in unexposed cases (P=0.0062). This study suggests that P16/CDKN2A gene inactivation in asbestos-exposed NSCLC cases mainly occurs via deletion, a feature also found in malignant mesothelioma, a tumor independent of tobacco smoking but associated with asbestos exposure, suggesting a possible relationship with an effect of asbestos fibers.

The French medico-legal concept of aptitude and fitness appraisal by occupational physicians: an ethical issue?

For many years, medical aptitude in occupational health, a French exception, did not raise any particular issue. However, from the 1980's onwards, this concept has been approached from a more critical point of view, authors questioning its compatibility with personal liberty. The increase in precarious working conditions have but reinforced such criticism, raising the question of the confrontation of such a concept with due respect of the right to work and the right for health protection. Special decrees, in particular the CMR decree (relating to carcinogenic, mutagenic and toxic substances for reproduction), issued in 2001, have added further force to the debate, particularly with regard to the problematic compatibility between the notice of aptitude and the respect of medical ethics and deontology. After having exposed the reasons behind the debate on aptitude in occupational health, and having identified the associated ethical issues, we will discuss the eventuality of the concept's abolition, together with possible replacement solutions.

Reliability of the proposed international classification of high-resolution computed tomography for occupational and environmental respiratory diseases.

PURPOSE: We have developed a classification of high-resolution computed tomography (HRCT) images for screening, surveillance and epidemiological studies of respiratory diseases caused by occupational and environmental factors. The proposed classification consists of three parts: a guideline explaining the elements of the classification scheme, a reading sheet, and reference films to aid in assessing thin-section CT films. We assessed the reliability of the proposed classification system by blinded, independent trial reading. MATERIALS AND METHODS: Seven independent radiologists and pulmonologists performed a trial reading to measure the reliability of the classification system using HRCT films from 27 pneumoconiosis patients and 7 normal controls. RESULTS: The agreement was moderate to good for rounded opacities (weighted kappa=0.68 and 0.64), irregular opacities (0.59, 0.48), honeycombing (0.65, 0.47), emphysema (0.76, 0.62) and large opacities (0.48, 0.52). Ground glass opacities (0.16, 0.20) showed poor to fair agreement. Intra-reader agreement of each of the seven readers was moderate to good (mean: weighted kappa=0.52-0.80) for parenchymal findings, but the agreement was relatively low (mean weighted kappa=0.52) for ground glass opacities. CONCLUSION: The proposed classification is able to describe early dust-related fibrotic changes and provide a semi-quantitative description of the HRCT features of major fibrotic changes in the parenchyma and pleura. Reliability, as measured by inter-reader agreement, was satisfactory.

Factors associated with cancer distress in the Asbestos Post-Exposure Survey (APEXS).

OBJECTIVES: CT-scan screening programs for lung cancer detection have been proposed in high-risk subjects, and more recently in former asbestos-exposed subjects. However, to date no data are available on psychological impact of such programs. The aim of this study is to examine the risk factors of psychological distress at baseline of a CT-scan screening program among asbestos-exposed subjects. METHODS: The Asbestos Post-Exposure Survey (APEXS) was carried out in France between October 2003 and December 2005 in order to screen asbestos-related diseases by CT-scan. Volunteers underwent self-administered questionnaires including an asbestos exposure assessment and, for a large sub-sample, a validated psychological distress scale. Non-exposed subjects were used as reference group. RESULTS: At baseline, a significant higher level of distress was observed in exposed subjects (n = 3,122) relative to the reference group (n = 486) after adjustment on age, sex, and tobacco status. This distress is associated independently with the self-perception of (i) intensity of asbestos exposure and (ii) the risk of current or future disease related to the asbestos exposure. The perception of the cancer risk related to asbestos seems to play a fundamental role in this psychological distress. CONCLUSION: In this study, asbestos-exposed subjects experienced a higher significant cancer distress than previously described in literature. These findings may be of potential public health importance. First, the impact of such occupational exposures on quality of life of patients who suffer from cancer related to these exposures has to be appraised. Secondly, the assessment of psychological impact of CT-scan screening programs among asbestos-exposed subjects is also required.

Children employed in the performing arts, advertising and fashion industry: what legal protection do they have?

Ill-treatment can sometimes take on an unfamiliar face. Particularly, this is the case for certain types of child employment. In France, as in most European countries, there are laws for protecting children and guaranteeing their right to schooling. Over and above the frequently observed apprenticeship contracts, obtained by eligible under 16 years, there is also the dispensatory case of children employed in the performing arts, advertising and the fashion industry. In France, legislators take the child's vulnerability into account when developing legislative and regulatory mechanisms, concerning the modalities of his/her professional activity, particularly in artistic fields and in fashion modelling. Since both may employ very young children, or even infants, one essential question ought to be raised: from a legal point of view, are these children sufficiently protected, with regard to the potential physical and psychological consequences of their particular professional activities?

Comparative analysis of medicolegal compensation for occupational cancers in France and other western European countries: development proposals.

In France, contemporary medicolegal reparation system of occupational diseases--in particular occupational cancer--has been questioned, constantly, due to changes in the state's legal system. For a long time, associated legislation was considered as a genuine social breakthrough. However, it shall remain acknowledged that over the past 15 years, it has been the French legal system itself that generated a certain level of inequality among victims of occupational diseases.. This inequality came to exist following certain jurisdictional understandings of legal matters, as well as the creation of exceptional schemes for granting compensation for physical injuries. It is agreed by both, courts and compensatory funds, that full compensation must be granted for particular group of victims. Yet, this is not the case as for granting compensation over occupational diseases, where reparation is on a set lump sum basis. In light of this proved inequality in the France legal system, with regard to the medicolegal reparation for loss or damage, associated with a claimant's occupational activity, we aim at investigating the procedures as practiced in various European countries occupational cancer in order to identify optimal compensation for these disorders.

Modelling prevalence and incidence of fibrosis and pleural plaques in asbestos-exposed populations for screening and follow-up: a cross-sectional study.

BACKGROUND: CT-Scan is currently under assessment for the screening of asbestos-related diseases. However, to date no consensus exists as to how to select high-risk asbestos-exposed populations suitable for such screening programs. The objective of this study is to select the most relevant exposure variables for the prediction of pleural plaques and asbestosis in order to guide clinicians in their use of CT-Scan. METHODS: A screening program of non malignant asbestos-related diseases by CT-scan was conducted among asbestos-exposed volunteers in France. Precise assessments of asbestos exposure were obtained by occupational hygiene measurements and a job-exposure matrix. Several parameters were calculated (time since first exposure, duration, intensity and cumulative exposure to asbestos). Predictive parameters of prevalence and incidence were then estimated by standard logistic and a complementary log-log regression models. RESULTS: 1011 subjects were recruited in this screening program among them 474 (46.9%) presented with pleural plaques and 61 (6.0%) with interstitial changes compatible with asbestosis on CT-scan. Time since first exposure (p < 0.0001) and either cumulative or mean exposure (p < 0.0001) showed independent associations with both pleural plaques and asbestosis prevalence and pleural plaques incidence. Modelling incidence of pleural plaques showed a 0.8% to 2.4% yearly increase for a mean exposure of 1 f/ml. CONCLUSION: Our findings confirmed the role played by time since first exposure and dose but not duration in asbestos-related diseases. We recommend to include these parameters in high-risk populations suitable for screening of these diseases. Short-periodicity of survey of pleural plaques by CT-Scan seemed not to be warranted.

Professional photosensitive eczema of fishermen by contact with bryozoans: disabling occupational dermatosis.

Eczema associated with bryozoans is a form of occupational dermatosis caused by a living animal, involving contact eczema, occasionally associated with photosensitivity and concerning fishermen on a quasi-elective basis. This affection can prove to be extremely disabling, frequently generating disastrous social consequences, since the eviction of the responsible allergen is very often synonymous to occupational reclassification, a measure which fishermen, highly attached to their profession, have great difficulty in accepting. Based on the description of three cases of photosensitive eczema associated with contact with the bryozoan, Alcyonidium gelatinosum, identified in fishermen from the English Channel coastline, we describe the characteristics and the specificities of this occupational dermatosis, then approach the issue of its prevention, which, unfortunately, remains limited.

Utility of osteopontin and serum mesothelin in malignant pleural mesothelioma diagnosis and prognosis assessment.

PURPOSE: Malignant mesothelioma is a highly aggressive tumor and is often diagnosed too late for a curative treatment. We compared diagnostic and prognostic values of mesothelin and osteopontin in 172 patients suspected of malignant pleural mesothelioma (MPM) and in a control group of 112 asymptomatic asbestos-exposed subjects. EXPERIMENTAL DESIGN: Osteopontin and mesothelin were assayed with commercial ELISA kits in a series of 43 patients with pleural metastases of various carcinomas, 33 patients with benign pleural lesions associated with asbestos exposure, 96 patients with MPMs, and 112 asbestos-exposed healthy subjects. Results were correlated with patient's diagnosis and survival. RESULTS: Serum osteopontin level was higher in MPM patients compared with healthy asbestos-exposed subjects and had a good capability to distinguish between these two populations. However, osteopontin was unable to distinguish between MPM and pleural metastatic carcinoma or benign pleural lesions associated with asbestos exposure. Neither plasma nor pleural fluid osteopontin were more powerful in this respect. Serum mesothelin had a good ability for diagnosing MPM but was unable to identify patients with nonepithelioid mesothelioma subtypes. Survival analysis identified tumor histologic subtype along with serum osteopontin and serum mesothelin as independent prognostic factors in mesothelioma patients. CONCLUSIONS: Osteopontin has a lower diagnostic accuracy than mesothelin in patients suspected of MPM. Insufficient specificity limits osteopontin utility as diagnostic marker. Both molecules have a potential value as prognostic markers.

Factors associated with early-stage pulmonary fibrosis as determined by high-resolution computed tomography among persons occupationally exposed to asbestos.

OBJECTIVES: Asbestosis remains difficult to diagnose, particularly in its early stages. The aim of this study was to determine criteria for independently associated features of pulmonary fibrosis in high-resolution computed tomograms among persons occupationally exposed to asbestos. METHODS: Retired persons with documented occupational asbestos exposure and no known asbestos-related diseases were assessed for occupational, clinical, functional respiratory, and chest X-ray criteria. In addition, they all underwent high-resolution computed tomography (HRCT) in the prone position. RESULTS: Altogether 51 (7.2%) of the 706 enrolled participants had features of pulmonary fibrosis consistent with asbestosis in the HRCT. Among those with small irregular opacities of <1/0 according to the 1980 International Labour Office Classification (ILO-C) in their X-rays, 5% had asbestosis in the HRCT. In a multivariate analysis, only age [odds ratio (OR) per year 1.08, 95% confidence interval (95% CI) 1.02-1.14], cumulative-exposure index (CEI) for asbestos (OR 6.4, 95% CI 1.5-28.4 for a CEI of > or =100 fibers/ml x years), and the presence of small irregular X-ray opacities of > or =1/0 ILO-C (OR 3.0, 95% CI 1.6-6.0) were independently associated with HRCT asbestosis. No combinations of these criteria simultaneously yielded high sensitivity and specificity for the diagnosis of early-stage HRCT asbestosis. Moreover, only 2% of the persons with a CEI of <25 fibers/ml x years had HRCT asbestosis, the finding confirming the low incidence of asbestosis for such low exposure, as previously reported on the basis of X-ray data. CONCLUSIONS: Additional research is needed to better identify the persons most likely to benefit from HRCT screening for asbestosis.

Asbestos exposure and radiological abnormalities among maintenance and custodian workers in buildings with friable asbestos-containing materials.

OBJECTIVES: Few studies have been carried out to evaluate the respiratory effects of asbestos exposure of custodian and maintenance workers. METHODS: By a multicentre cross-sectional study, 277 custodian and maintenance employees working in buildings with friable asbestos-containing materials and 87 unexposed subjects were studied for radiological abnormalities by use of the International Labour Office (ILO) classification of radiographs of pneumoconiosis, in relation to parameters of asbestos exposure. RESULTS: The cumulative asbestos exposure index was generally low (fewer than 5 fibres/ml x years in 82.3% of exposed workers). On multivariate analysis, pleural thickening was significantly related to latency since onset of exposure to asbestos in exposed workers, after adjustment for age, body mass index and tobacco smoking. CONCLUSIONS: Asbestos exposure of custodian and maintenance employees in buildings with friable asbestos-containing materials might be associated with an excess of pleural thickening on chest X-rays.