[Prevalence and distribution of asbestos lung residue in a Spanish urban population]

Pleural plaques by inhalation of asbestos fibers

Introduction

Asbestos fiber pleural plaque is characterized by lesions composed of fibrous tissue that are located in the parietal pleura. They usually appear in up to 3 to 58% of workers who were exposed to asbestos fiber, and 0.5 to 8% in the general population. The objective of this article is to present a case report of a patient whose chest x-ray showed pleural changes associated with exposure to asbestos fibers.

Case report

A 49-year-old male patient, construction worker with a history of exposure to asbestos fibers, underwent a chest x-ray performed according to International Labor Organization (ILO) standards, which revealed focal pleural changes. Subsequently, the presence of pleural plaques was confirmed by computed tomography (CT) scan of the chest.

Discussion

Chest x-ray with ILO technique is the basic instrument for the identification of diseases related to asbestos fiber exposure. The study should be completed with a CT scan of the chest, whose sensitivity is greater, allowing early detection of pleural abnormalities. It is essential to obtain a detailed occupational history, since it is the most reliable and practical method to measure asbestos fiber exposure.

Validation of an Asbestos Exposure Questionnaire (QEAS-7) for Clinical Practice

Introduction: The seven-item QEAS-7 questionnaire (exposure to asbestos questionnaire) has been designed as a useful and simple tool to establish the probability of exposure to asbestos. The objective of the present study is to validate the QEAS-7 following the recommended methodology. Methods: The QEAS-7 was prospectively administered to 90 subjects with and without asbestos-related disease (ARD), on two consecutive occasions by two independent researchers. Logical and content validity was evaluated by a committee of experts and construct validity through hypothesis testing. Intra- and interobserver reliability was assessed by calculating Cohen’s Kappa index (κ), which was estimated as weak if below 0.40, moderate if between 0.41 and 0.60 and good/very good if above 0.60. The comparison between proportions was examined using Pearson’s Chi-square test. Results: The majority of participants (88.9%) were male. Mean age was 70.8 years (SD = 8.4) and most of the sample had completed primary education but had not progressed further (62.2%). Forty-three had ARD. The logical, content and construct validity of the QEAS-7 was considered adequate both by a committee of experts and by the users interviewed. The mean administration time was 9 min and 25 s (SD = 3 min and 49 s). The verification of the five hypotheses confirmed the construct validity and the intra- and interobserver reliability to be κ = 0.93 and κ = 0.50 respectively. The concordance in the estimation of asbestos exposure was κ = 0.65. Conclusions: The QEAS-7 is a simple, valid and reliable tool for estimating the probability of exposure to asbestos. Its application in clinical practice appears justified. What is already known about this subject? No studies have been published to date on the validation of specific questionnaires designed to determine asbestos exposure for routine use by healthcare staff in the clinical setting. What are the new findings? This questionnaire can be considered a comprehensible, viable, valid and reliable instrument for identifying exposure to asbestos. Its brevity and simplicity of administration make it ideally suited for use in daily clinical practice. How might this impact on policy or clinical practice in the foreseeable future? This questionnaire can be of help for physicians attending to patients with suspected asbestos-related diseases both in the hospital and in the primary care setting.

Asbestos Bodies Burden in the Autopsy Lung Tissue from General Thai Population

Background

Chrysotile asbestos has been used in Thailand for over 30 years mainly in asbestos-cement wall and roof tiles. In non-exposed subject, asbestos fiber can contaminate in ambient indoor and outdoor environments.

Objective

The aim of the present study is to evaluate the current prevalence and volume of AB load in general Thai population.

Methods

Lung tissues were obtained from 200 autopsy cases. Asbestos Bodies (AB) were identified with light microscopy using the tissue digestion and membrane filtration method. Results are reported as AB/g wet lung tissue.

Results

AB was identified in 97(48.5%) out of 200 cases. The AB level ranged from 0.19-14.4 AB/g wet lung. Most of the positive cases (99%) have less than 10 AB/g wet lung. Only one case exhibited a high value at 14.4 AB/g wet lung. Age, gender, occupation and hometown were found to have no effect on AB burden in autopsy lung tissue from this study.

Conclusion

The prevalence of AB in autopsy lung tissue from general Thai population is 48.5% and the AB level ranges from 0-14.4 AB/g wet lung in consistent with non-occupational asbestos exposure level regarding several reference reports.

First Identification of Pulmonary Asbestos Fibres in a Spanish Population

INTRODUCTION

This study aimed to characterize, for the first time in Spain, the type of asbestos fibres (AF) in the lungs of exposed and non-exposed populations.

MATERIALS AND METHODS

Lung samples from 38 subjects living in Barcelona and Ferrol, Spain, were studied, which were divided into three groups: Group A-five subjects without known respiratory disease; Group B-20 ex-shipyard workers and Group C-13 patients with lung cancer. After eliminating the organic material, the inorganic residue was analysed using electronic microscopy (EM). To identify the type of fibre, the samples were analysed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX).

RESULTS

All the fibres identified corresponded to amphiboles (crocidolite 45%, anthophyllite 22%, tremolite 16%, amosite 15% and actinolite 3%). In 14 patients (37%), a single type of asbestos was found in the lungs (amosite in two, actinolite in one, anthophyllite in four, crocidolite in five and tremolite in two). Forty-six percent of the AF analysed had a length > 5 µm and a diameter < 0.2 µm.

CONCLUSIONS

The results of this study provide the first data on the type of asbestos retained in the lung of Spanish population. A particularly striking finding is the exclusive retention of amphiboles, which suggests that chrysotile is eliminated after inhalation. Our findings support estimations considering Spain and other southern European countries with similar asbestos imports and consumption at a high risk to develop asbestos-related diseases in the years to come.

Recommendations for the Diagnosis and Management of Asbestos-Related Pleural and Pulmonary Disease

Asbestos is the term used for a set of mineral silicates that tend to break up into fibers. Its use has been associated with numerous diseases affecting the lung and pleura in particular, all of which are characterized by their long period of latency. Asbestos, moreover, has been recognized by the WHO as a Group IA carcinogen since 1987 and its use was banned in Spain in 2002. The publication in 2013 of the 3rd edition of the specific asbestos health monitoring protocol, together with the development of new diagnostic techniques, prompted the SEPAR EROM group to sponsor publication of guidelines, which review the clinical, radiological and functional aspects of the different asbestos-related diseases. Recommendations have also been made for the diagnosis and follow-up of exposed patients. These recommendations were drawn up in accordance with the GRADE classification system.