The prevalence of pleural plaques and/or pulmonary changes among construction workers in Okayama, Japan

Environmental asbestos exposure and nonmalignant pleural findings: a retrospective evaluation of a five-year chest CT repository

This registry-based case-control study aimed to assess the association between asbestos deposits in the birthplace and/or residence and nonmalignant pleural findings, namely pleural plaques (PPs) and pleural thickening (PT), on chest CT scans. In total, 39,472 CT scans obtained over five years in a tertiary referral hospital in Ankara, Turkey, were evaluated. Cases involving patients with PP (n = 537), PT (n = 263), PP&PT (n = 69), and controls (n = 543) from the same study base without those conditions were included. Each case group was compared to controls using unconditional logistic regression. The presence of asbestos deposits in the district of birthplace (adjusted OR = 2.13, 95% CI: 1.35-3.37) and both birthplace and residence (aOR = 4.32, 95% CI: 2.26-8.27) was significantly related to the PPs. As the importance of environmental asbestos exposure in Turkey continues, future prospective studies could contribute to developing screening strategies.

Malignant mesothelioma in construction workers: the Apulia regional mesothelioma register, Southern Italy

Objective

Asbestos was widely used in construction in both a friable and a compact form until the 1990s, before its use was banned. Today, many of these materials are still in situ and represent a source of risk for construction workers. The objective of the study was to analyse the cases of mesothelioma arising among construction workers registered in the Apulia regional register of mesothelioma.

Results

For the period 1993–2018, there were 178 male cases, and 10.2% of the cases were present in the regional register. The average age at diagnosis was 64.7 years. The site was pleural in 96.06% of cases, with a diagnosis of certainty in 86.5% of the total cases and 61.8% of cases with epithelial histology. The average latency is 43.9 years. In 75.2% of cases, the exposure began between 1941 and 1970, with an average duration of 24.3 years. The age at the start of exposure in 68.5% of cases is between 8 and 20 years. The ORs were 2.5 (C.I. 95% 1.01–6.17) for the epithelioid histotype and the high duration of exposure. The data underline the need for prevention and information on all activities involving construction workers in which asbestos-containing materials are still used.

Prevention of Asbestos Exposure in Latin America within a Global Public Health Perspective

Background:

Asbestos consumption in Latin America (LA) amounts to 10% of yearly global production. Little is known about the impact of asbestos exposure in the region.

Objective:

To discuss scientific and socio-economic issues and conflicts of interest and to summarize epidemiological data of asbestos health effects in LA.

Discussion:

Recent data on chrysotile strengthened the evidence of its carcinogenicity and showed an excessive risk of lung cancer at cumulative exposure levels as low as 1.5 fibre-years/ml. Technology for substitution is available for all asbestos-containing products and ceasing asbestos production and manufacturing will not result in unemployment and loss of income, except for the mining industry. The flawed arguments used by the industry to maintain its market, both to the public and in courtrooms, strongly relies on the lack of local evidence of the ill effects and on the invisibility of asbestos-related diseases in LA, due to the limited number of studies and the exposed workers’ difficulty accessing health services. The few epidemiological studies available show clear evidence of clusters of mesothelioma in municipalities with a history of asbestos consumption and a forecasted rise in its incidence in Argentina and Brazil for the next decade. In Brazil, non-governmental organizations of asbestos workers were pivotal to counterbalance misinformation and inequities, ending recently in a Supreme Court decision backing an asbestos ban. In parallel, continuous efforts should be made to stimulate the growth of competent and ethical researchers to convey adequate information to the scientific community and to the general public.

Progressive plasterer's pneumoconiosis complicated by fibrotic interstitial pneumonia: a case report

BACKGROUND

Although the prevalence of pneumoconiosis has been decreasing due to improvements in working conditions and regular health examinations, occupational hygiene measures are still being established. Plasterers encounter a number of hazardous materials that may be inhaled in the absence of sufficient protection.

CASE PRESENTATION

A 64-year-old man who plastered without any dust protection for more than 40 years was referred to our hospital with suspected interstitial pneumonia. Mixed dust pneumoconiosis and an unusual interstitial pneumonia (UIP) pattern with fibroblastic foci were diagnosed by video-assisted thoracoscopic surgery, and an elemental analysis detected elements included in plaster work materials. Despite the cessation of plaster work and administration of nintedanib, the patient developed advanced respiratory failure.

CONCLUSION

Plasterers are at an increased risk of pneumoconiosis and may have a poor prognosis when complicated by the UIP pattern. Thorough dust protection and careful monitoring are needed.

Pleural abnormalities in the Framingham Heart Study: prevalence and CT image features

BACKGROUND

The prevalence of pleural abnormalities in the general population is an epidemiologically important index of asbestos exposure, which has not been investigated since a radiography-based study in 1980.

METHODS

We examined 2633 chest CT scans (mean 59.2 years, 50% female) from the Framingham Heart Study (FHS) for the presence and image characteristics of pleural plaques and diffuse pleural thickening. Demographics and pulmonary function were stratified by the presence of pleural abnormalities in association with interstitial lung abnormalities.

RESULTS

Pleural abnormalities were present in 1.5% (95% CI 1.1% to 2.1%). Pleural lesions were most commonly bilateral (90.0%), multiple (77.5%), calcified (97.5%) and commonly involved posterior (lower: 92.5%, middle: 87.5%), anterior (upper: 77.5%, middle: 77.5%) and diaphragmatic areas (72.5%). Participants with pleural abnormalities were significantly older (75.7 years, p <0.0001), male (92.5%, p <0.0001), former or current smokers (80.0%, p <0.001) with higher pack-years (33.3, p <0.0001). No significant reduction was noted in pulmonary function measures (p=0.07-0.94) when adjusted for the associated covariates, likely due to small number of cases with pleural abnormalities. Information about prior history of asbestos exposure and occupation was not available.

CONCLUSIONS

Pleural plaques and diffuse pleural thickening are present on CT in 1.5% of the FHS cohort. The current prevalence of the pleural abnormalities is smaller than that reported in the previous population-based study using chest radiography, likely representing lower asbestos exposure in recent decades. The posterior portion of the pleura is most frequently involved but the anterior portion is also commonly involved.

Pleural irregularities and mediastinal pleural involvement in early stages of malignant pleural mesothelioma and benign asbestos pleural effusion

OBJECTIVE

To elucidate differences in the level and localization of pleural irregularities in early malignant pleural mesothelioma (eMPM) and benign asbestos pleural effusion (BAPE) using CT.

STUDY DESIGN

Retrospective assessment of CT findings of consecutive patients with BAPE at a single centre and patients with eMPM reported in Japanese vital statistics.

METHODOLOGY

Thirty-six patients with confirmed diagnoses of BAPE and sixty-six patients with confirmed diagnoses of eMPM (mesothelioma stages T1 or T2) were included. Informed consent, CT scans, and clinical and pathologic details were obtained for all patients and were reviewed by one radiologist, two pathologists, and two pulmonologists. Asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening were assessed in all patients.

RESULTS

Prevalence of asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening was significantly higher in the BAPE group. Low-level irregularity was more common in the BAPE group (p<0.001), whereas high-level irregularity, mediastinal localization, and interlobar fissure were more prevalent in the eMPM group (p<0.001). Interlobar pleural irregularity was not observed in any patients in the BAPE group, although 55% of patients in the eMPM group showed interlobar pleural irregularity. Mediastinal pleural involvement was observed in 74% of patients in the eMPM group and had a positive predictive value of 89%.

CONCLUSION

This study demonstrates that the level and localization of plural irregularities significantly differed between patients with BAPE and eMPM. Large-scale prospective studies are needed to fully establish the diagnostic utility of such differences.

Use of Anti-Noxa Antibody for Differential Diagnosis between Epithelioid Mesothelioma and Reactive Mesothelial Hyperplasia

OBJECTIVES

The histological differential diagnosis between epithelioid mesothelioma (EM) and reactive mesothelial hyperplasia (RMH) is not always straightforward. The aim of the present study was to search for new immunohistochemical markers to distinguish EM from RMH.

METHODS

We evaluated and compared the expression of apoptosis-related genes in EM and RMH by real-time RT-PCR array analysis followed by clustering of significant gene expression. Immunohistochemical staining and statistical analysis of Noxa expression in 81 cases of EM and 55 cases of RMH were performed and compared with the utility of other previously reported antibodies such as Desmin, EMA, GLUT-1, IMP-3 and CD146.

RESULTS

Noxa mRNA expression levels were found to be increased in EM when compared to RMH by RT-PCR array analysis. In the immunohistochemical analysis, Noxa showed sensitivity of 69.0%, specificity of 93.6% and positive predictive value of 93.0% as a positive marker of EM in distinguishing it from RMH, and these values were almost similar to IMP-3.

CONCLUSION

Noxa is a marker with relatively high specificity, and can be used to distinguish EM from RMH. It would be a valuable addition to the current antibody panel used for the differential diagnosis of EM and RMH.

Environmental asbestos exposure in rural Turkey and risk of lung cancer

The aim of this study was to determine the risk of lung cancer in a cohort of villagers with environmental asbestos exposure. The study was carried out as a field-based epidemiological study. Information from 3143 individuals in 15 asbestos exposed villages and 2175 individuals in 12 control villages was obtained. Asbestos fiber type to which villagers were exposed mainly was tremolite or tremolite, actinolite, chrysotile mixtures. The cumulative fiber count of the villagers during their lifespan ranged from 0.19 to 4.61 fiber-years/ml. The annual average incidence ratio of lung cancer was 135.21/100,000 persons/year in men and 47.28 in women in the asbestos exposed villages. For the control villages, this ratio was 60.15/100,000 person/year in men and 15.06 in women. Being a male, advanced age, smoking and asbestos exposure were established to increase the risk of lung cancer. Environmental asbestos exposure in rural area is a risk factor for lung cancer independent of smoking.

Chest imaging and lung function impairment after long-term occupational exposure to low concentrations of chrysotile

The aim of the present study was the investigation of radiographic findings in relation to lung function after occupational exposure to permissible levels of relatively pure chrysotile (0.5-3% amphiboles). We studied 266 out of the total 317 employees who have worked in an asbestos cement factory during the period 1968-2004 with chest x-ray, high-resolution computed tomography (HRCT) and lung function tests. Sensitivity of chest x-ray was 43% compared to HRCT. Abnormal HRCT findings were found in 75 subjects (67%) and were related to age, occupational exposure duration, and spirometric data. The presence of parenchymal or visceral pleural lesions (exclusively or as the predominant abnormality) was being accompanied by lower total lung capacity and diffusion capacity. HRCT was much more sensitive than chest x-ray for occupational chrysotile exposure. Lung function impairment was related with parenchymal but not with pleural HRCT abnormalities.

Pleural plaque profiles on the chest radiographs and CT scans of asbestos-exposed Japanese construction workers

Pleural plaques are asymptomatic focal thickenings of the pleura and considered the hallmark of asbestos exposure. However, it is often difficult to detect pleural plaques on chest x-rays (CXR). In a retrospective study, using chest CT scans of 140 Japanese asbestos-exposed construction workers who have probable or definite findings of pleural plaque on CXR; firstly, we proposed plaque morphology-based classification for CXR findings, and then we examined if those classified findings could be confirmed as pleural plaques on CT scans. Our morphology-based classification of pleural plaque findings included nine types. The percentages of confirmed pleural plaques on CT scans by type (number of confirmed pleural plaque on CT/number of observed on CXR) were 93% (40/43) for straight, 89% (56/63) for diamond, 88% (7/8) for double, 83% (19/23) for tapered medially, 80% (20/25) for parallel, 77% (23/30) for crescent, 79% (11/14) for tenting, 72% (18/25) for tapered-laterally (long type), and 0% (0/9) for tapered-laterally (short type). When added to the ILO classification, morphology-based classification of CXR pleural plaque findings makes its detection easier and hence chest radiograph continues to be a suitable tool for screening asbestos-related pleural plaques based on its simplicity, low radiation exposure, wide availability and cost-effectiveness.

[What are the tools for post-occupational follow-up, how should they be performed and what are their performance, limits and benefit/risk ratio? Chest X-Ray and CT scan]

Chest radiography and computed tomography (CT) are the two radiological techniques used for the follow-up of people exposed to asbestos. Since the last conference of consensus (1999), the scientific literature has primarily covered high-resolution CT and high-resolution volume CT (HR-VCT). We consider in turn the contribution of digital thoracic radiography, recommendations for the performance of HR-VCT to ensure the quality of examination while controlling the delivered radiation dose, and the need to refer to the "CT atlas of benign diseases related to asbestos exposure", published by a group of French experts in 2007, for interpretation. The results of the published studies concerning radiography or CT are then reviewed. We note the great interobserver variability in the recognition of pleural plaques and asbestosis, indicating the need for adequate training of radiologists, and the importance of defining standardized, quantified criteria for CT abnormalities. The very low agreement between thoracic and general radiologists must be taken into account. The reading of CT scans in cases of occupational exposure to asbestos should be entrusted to thoracic radiologists or to general radiologists having validated specific training. A double interpretation of CT could be considered in medicosocial requests. CT is more sensitive than chest radiography in the detection of bronchial carcinoma but generates a great number of false positive results (96 to 99%). No scientific data are available to assess the role of imaging by either CT or chest radiography in the early detection of mesothelioma.

Refractory ceramic fiber (RCF) toxicity and epidemiology: a review

This paper provides a review of the relevant literature on refractory ceramic fibers (RCFs), summarizing relevant data and information on the manufacture, processing, applications, potential occupational exposure, toxicology, epidemiology, risk analysis, and risk management. RCFs are amorphous fibers used for high-temperature insulation applications. RCFs are less durable/biopersistent than amphibole asbestos, but more durable/biopersistent than many other synthetic vitreous fibers (SVFs). Moreover, as produced/used, some RCFs are respirable. Toxicology studies with rodents using various exposure methods have shown that RCFs can cause fibrosis, lung cancer, and mesothelioma. Interpretation of these animal studies is difficult for various reasons (e.g., overload in chronic inhalation bioassays). Epidemiological studies of occupationally exposed cohorts in Europe and the United States have demonstrated measurable effects (e.g., mild respiratory symptoms and pleural plaques) but no disease (i.e., no interstitial fibrosis, no excess lung cancer, and no mesothelioma) to date. The RCF industry, working cooperatively with various government agencies in the United States, has developed a comprehensive product stewardship program (PSP) to identify and control risks associated with occupational exposure. One provision of the PSP is the adoption of a voluntary recommended exposure guideline (REG) of 0.5 fibers/milliliter (f/ml). Selected on the basis of prudence and demonstrated feasibility, compliance with the REG should reduce risks to levels between 0.073/1000 and 1.2/1000, based on extrapolations from chronic animal inhalation studies.

Value of immunohistochemistry in the differential diagnosis of pleural sarcomatoid mesothelioma from lung sarcomatoid carcinoma

AIMS

The differential diagnosis of pleural sarcomatoid mesothelioma (SM) from lung sarcomatoid carcinoma (LSC) invading parietal pleura and chest wall is a challenging issue. The aim of this study was to identify useful antibodies that can be used for the differential diagnosis of pleural SM from LSC.

METHODS AND RESULTS

Forty-five cases of pleural SM and 27 cases of LSC were immunohistochemically analysed by using 15 commercially available antibodies, including D2-40 and antibodies to calretinin, thrombomodulin, Wilms' Tumour 1, carcinoembryonic antigen (CEA), Napsin A, thyroid transcription factor (TTF)-1, pan-cytokeratin, CAM5.2, epithelial membrane antigen, Ber-EP4, MOC-31, alpha-smooth muscle actin, h-caldesmon and desmin. The results revealed that D2-40 positivity was significantly higher in pleural SM (86.7%) than in LSC (25.9%). The positivity of the adenocarcinoma markers, including CEA, Napsin A, and TTF-1, was low even in LSC.

CONCLUSIONS

Evaluating the positivity and degree of staining of the well-known mesothelial marker D2-40 could be applied to differentiate pleural SM from the sarcomatoid component of LSC, in addition to assessing clinical and radiological information.

Accuracy of pathological diagnosis of mesothelioma cases in Japan: clinicopathological analysis of 382 cases

Incidences of mesothelioma are on the rise in Japan. However, the accurate frequency of mesothelioma occurrence is still unknown. The aim of this study is to clarify the accuracy of pathological diagnosis of mesothelioma. Among the 2742 mesothelioma death cases extracted from the document "Vital Statistics of Japan" for 2003-2005, pathological materials were obtained for 382 cases. After these materials were reviewed and immunohistochemical analyses were conducted, mesothelioma was diagnosed by discussions based on clinical and radiological information. Sixty-five cases (17.0%) were categorized as "definitely not/unlikely" mesotheliomas, and 273 cases (71.5%) were categorized as "probable/definite" mesotheliomas. The percentage of "probable/definite" pleural and peritoneal mesothelioma cases in males was 74.3% and 87.5%, respectively, and that of pleural cases in females was 59.2%; however, the percentage of "probable/definite" peritoneal cases in females was only 22.2%. These results suggest that the diagnostic accuracy of mesothelioma is relatively low in females and in cases of peritoneal and sarcomatoid subtype mesotheliomas; furthermore, approximately 15% of cases of deaths due to mesothelioma in Japan are diagnostically suspicious.

Non-malignant occupational respiratory diseases in Germany in comparison with those of other countries

OBJECTIVE

To present recent data on the occurrence of non-malignant occupational airway diseases in Germany and to compare mainly affected occupations of obstructive airway diseases caused by allergens and irritants with available surveillance data from other countries.

METHODS

Sources of German data were statistics for the year 2003 of the Ministry of Labour and Social Affairs and of the federation of statutory accident insurance institutions for the industrial sector.

RESULTS

Confirmed cases of non-malignant occupational respiratory diseases in Germany are mainly benign asbestos-associated diseases (occupational disease no. 4103: 1,975 cases), silicosis/coal worker's pneumoconiosis (occupational disease no. 4101: 1,158 cases), obstructive airway diseases due to allergens (occupational disease no. 4301: 935 cases), chronic obstructive bronchitis and/or emphysema in hard coal miners (occupational disease no. 4111: 414 cases), obstructive airway diseases due to irritants and toxic agents (occupational disease no. 4302: 181 cases), diseases caused by ionising radiation (171 cases), diseases due to isocyanates (occupational disease no. 1315: 55 cases), and 22 cases of other rare occupational lung and airway diseases. Miners, bakers, chemical workers, hairdressers and health care workers are mostly affected. Bakers were also frequently affected by occupational asthma in Finland, France, Sweden, the United Kingdom, the Piedmont region in Italy, South Africa, and New Zealand. Further, high frequencies of occupational asthma were reported for health care workers in France, Italy, New Jersey, Michigan, and South Africa.

CONCLUSION

Despite completely different legal definitions and regulations, comparably high numbers of occupational obstructive diseases in western countries require better primary and secondary prevention in industries with high incidence, especially in bakeries, the health care sector, farming, and mining. Furthermore, there is a urgent need for harmonization of recognition and compensation systems for occupational diseases as well as of respective preventive strategies within the European Union.

The usefulness of computed tomography in detecting asbestos-related pleural abnormalities in people who had indeterminate chest radiographs: the Libby, MT, experience

This epidemiological study was conducted to determine whether high-resolution computed tomography (HRCT) is useful to screen for pulmonary abnormalities in people exposed to vermiculite containing asbestos. During June-September 2001, we evaluated HRCT of 353 people in Libby, MT, who had been exposed to asbestiform minerals associated with vermiculite. Of these, 334 participants of the summer 2000 medical testing program underwent HRCT of the chest at St. John's Lutheran Hospital and 19 eligible people who recently had undergone an HRCT scan at the same facility and under the same testing protocol allowed the study reviewers to use that scan. All 353 study participants were former vermiculite mine/mill workers (n = 55), their household contacts (n = 99), and people exposed to vermiculite through recreational or other activities (n = 199). Participants' 2000 medical testing results indicated only one of the three B-reader chest radiograph reviewers had reported a pleural abnormality (indeterminate chest radiograph). Three expert computer tomography (CT) scan evaluators reviewed the HRCT scans and identified pleural abnormalities in 98 (27.8%) of the 353 participants whose previous chest radiographs were classified indeterminate. Of these 98 people, 69 (70.4%) were either former vermiculite mine/mill workers or household contacts, and 40 (40.8%) showed pleural calcification on HRCT. Thirty out of the 40 people with pleural calcification reported having no occupational exposure to either Libby vermiculite or asbestos. Our findings indicate that low-dose HRCT can be considered for screening certain former vermiculite mine/mill workers and their household contacts who have indeterminate chest radiographs and may be useful for diagnosing a suspicious finding on a chest radiograph, particularly in a high-risk person.

Radiographic abnormalities among construction workers exposed to quartz containing dust

BACKGROUND

Construction workers are exposed to quartz containing respirable dust, at levels that may cause fibrosis in the lungs. Studies so far have not established a dose-response relation for radiographic abnormalities for this occupational group.

AIMS

To measure the extent of radiographic abnormalities among construction workers primarily exposed to quartz containing respirable dust.

METHODS

A cross sectional study on radiographic abnormalities indicative of pneumoconiosis was conducted among 1339 construction workers mainly involved in grinding, (jack)-hammering, drilling, cutting, sawing, and polishing. Radiological abnormalities were determined by median results of the 1980 International Labour Organisation system of three certified "B" readers. Questionnaires were used for assessment of occupational history, presence of respiratory diseases, and symptoms and smoking habits.

RESULTS

An abnormality of ILO profusion category 1/0 and greater was observed on 10.2% of the chest radiographs, and profusion category of 1/1 or greater on 2.9% of the radiographs. The average duration of exposure of this group was 19 years and the average age was 42. The predominant type of small opacities (irregularly shaped) is presumably indicative of mixed dust pneumoconiosis. The prevalence of early signs of nodular silicosis (small rounded opacities of category 1/0 or greater) was low (0.8%).

CONCLUSIONS

The study suggests an elevated risk of radiographic abnormalities among these workers with expected high exposure. An association between radiographic abnormalities and cumulative exposure to quartz containing dust from construction sites was observed, after correction for potentially confounding variables.