Assessment of environmental asbestos exposure in Turkey by bronchoalveolar lavage

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.

Update of in vitro, in vivo and ex vivo fluoro-edenite effects on malignant mesothelioma: A systematic review (Review)

Fluoro-edenite (FE), asbestiform fiber found in Biancavilla (Sicily, Italy), presents various characteristics similar to the asbestos group, in particular two fibrous phases tremolite and actinolite. Indeed, epidemiological studies have shown that FE fibers have similar effects to those of asbestos fibers. Such studies have reported a high incidence of malignant mesothelioma (MM), an aggressive neoplasm of the serosal membranes lining the pleural cavity, in individuals residing there due to FE exposure in Biancavilla related to environmental contamination. Evidence has led to the classification of FE as a Group 1 human carcinogen by the International Agency for Research on Cancer (IARC). The aim of this systematic review is to compare the results achieved in in vitro, in vivo and ex vivo experimental studies involving FE in order to update the current knowledge on the pathogenesis and molecular mechanisms responsible for FE-mediated MM development as well as the availability of effective biomarkers for MM prevention and diagnosis. This review is focused on the pathophysiological mechanisms mediated by inflammation induced by FE fiber exposure and which are responsible for MM development. This review also discusses the discovery of new diagnostic and prognostic biomarkers for the management of this pathology. It is known that the risk of cancer development increases with chronic inflammation, arising from enhanced reactive oxygen species (ROS) and NO^• production stimulated by the body to remove exogenous agents, causing DNA damage and enhanced signal transduction that may lead to activation of oncogenes. Studies concerning MM biomarker discovery indicate that several biomarkers have been proposed for MM, but mesothelin is the only Food and Drug Administration (FDA)-approved biomarker for MM, with limitations. In recent studies, in silico analysis to identify selected miRNAs highly deregulated in cancer samples when compared with normal control have been developed. This in silico approach could represent an effort in the field of biomarker discovery for MM.

Modulation of microRNA expression levels after naturally occurring asbestiform fibers exposure as a diagnostic biomarker of mesothelial neoplastic transformation

Fluoro-edenite (FE) is a silicate mineral identified in the lava products of Monte Calvario from stone quarries located in the southeast of Biancavilla, a small city of the Etnean volcanic complex (Sicily, Italy). Inhalation of FE fibers has been associated with a higher incidence of Malignant Mesothelioma (MM), a highly aggressive neoplasm of the serosal membranes lining the pleural cavity. Only 5% of MM patients are diagnosed at an early stage and the median survival is approximate 6-12 months. Many diagnostic biomarkers have been proposed for MM. Several studies demonstrated that microRNAs (miRNAs) may be used as good non-invasive diagnostics, as well as prognostic biomarkers for various human diseases, including cancer. On these bases, the aim of the present study was to identify a set of miRNAs involved in the development and progression of MM and potentially used as diagnostic biomarkers. For these purposes, in silico analyses were performed on healthy/exposed to asbestos fibers subjects vs. patients with MM. These analyses revealed a set of miRNAs strictly involved in MM by merging the lists of miRNAs found differentially expressed in the three miRNA expression datasets analyzed. The result of these computational evaluations allowed the execution of functional in vitro experiments performed on normal pleural mesothelial cell line (MeT-5A) and MM cell line (JU77) in order to test the carcinogenetic effects and epigenetic modulation induced by FE exposure. The in vitro results showed that the expression levels of hsa-miR-323a-3p vary significantly in both supernatant- and cell-derived miRNAs derived from treated and untreated cells. Secreted and cellular hsa-miR-101-3p in MeT-5A treated with FE fibers and JU77 cells showed different trends of expression. As regard hsa-miR-20b-5p, there was no differential expression between secreted and cellular hsa-miR-20b-5p. This miRNA has been shown a significant up-regulation in JU77 cells vs. control and treated MeT-5A. As a future plan, translational analyses will be performed on a subset of patients chronically exposed to FE fibers to further verify the clinical role of such miRNAs in high-risk individuals and their possible use as biomarkers of FE exposure or MM early onset.

Comparison of serum biochemical markers in patients with mesothelioma and pleural plaques versus healthy individuals exposed to environmental asbestos

Background

In this study, we aimed to compare serum biochemical markers in patients with malignant pleural mesothelioma and pleural plaques versus healthy individuals exposed to environmental asbestos.

Methods

Between September 01, 2010 and March 31, 2011, a total of 540 participants (354 males, 186 females; mean age 61.4 years; range, 35 to 89 years) were included in the study. The participants were divided into four groups as follows: (1) patients with pleural plaques (n=277); (2) healthy individuals with normal chest X-rays who were exposed to environmental asbestos (n=121); (3) healthy individuals with normal chest X-rays who were not exposed to environmental asbestos (n=118); and (4) patients with malignant pleural mesothelioma (n=24). Serum levels of carcinoembryonic antigen, cancer antigen 125, 15-3, 19-9, free T3, free T4, thyroidstimulating hormone, vitamin B12, folate, and ferritin were measured.

Results

Serum cancer antigen 125, 15-3, folic acid, vitamin B12, and ferritin levels were higher with lower free T3 levels in Group 4 than the other groups. The areas under the curve for cancer antigen 125 and 15-3 were 0.78 and 0.67, respectively in the differential diagnosis of mesothelioma from other pathologies (p<0.001 for both). Optimal limits of these biomarkers were 13.63 and 18.43 ng/mL, respectively with 83% and 75% sensitivity and 69% and 48% specificity, respectively.

Conclusion

The combination or individual use of serum cancer antigen 125, 15-3, folic acid, vitamin B12, and ferritin levels may be helpful for early diagnosis and treatment of malignant pleural mesothelioma.

Ovarian cancer in a former asbestos textile factory worker: a case report

Background

The International Agency for Research on Cancer (IARC) defined that asbestos is a group 1 substance that causes lung cancer, mesothelioma (pleura and peritoneum), laryngeal cancer, and ovarian cancer in humans. Many studies on lung cancer, and mesothelioma caused by asbestos exposure have been conducted, but there was no case report of ovarian cancer due to asbestos exposure in Korea. We describe a case of ovarian cancer caused by asbestos exposure in a worker who worked at an asbestos textile factory for 3 years and 7 months in the late 1970s.

Case presentation

A 57-year-old woman visited the hospital because she had difficulty urinating. Ovarian cancer was suspected in radiologic examination, and exploratory laparotomy was performed. She was diagnosed with epithelial ovarian cancer. The patient did not undergo postoperative chemotherapy and recovered. She joined the asbestos factory in March 1976 and engaged in asbestos textile twisting and spinning for 1 year, 2 years and 7 months respectively. In addition, she lived near the asbestos factory for more than 20 years. There was no other specificity or family history.

Conclusion

Considering the patient’s occupational and environmental history, it is estimated that she had been exposed to asbestos significantly, so we determined that ovarian cancer in the patient is highly correlated with the occupational exposure of asbestos and environmental exposure is a possible cause as well. Social devices are needed to prevent further exposure to asbestos. It is also necessary to recognize that ovarian cancer can occur in workers who have previously been exposed to asbestos, and the education and social compensation for those workers are needed.

Environmental asbestos exposure and risk of mesothelioma

Mesothelioma is commonly considered an occupational disease occurring as a result of asbestos exposure in the workplace. Several avenues for environmental asbestos exposures have been described and may be associated with asbestos related disease, including mesothelioma. Worker take-home asbestos, or para-occupational exposure, has been well documented and is the most commonly reported pathway for asbestos exposure among mesothelioma cases that do not have history of occupational asbestos exposure. Observational studies have evaluated several communities with elevated mesothelioma incidence and environmental exposures attributed to local asbestos-related industries. Potential, but uncertain, mesothelioma risk also may be associated with general population asbestos exposure through contact with asbestos-containing commercial products, particularly housing materials that can be easily disturbed through normal activity. Finally, studies have described elevated mesothelioma incidence in several areas where populations are exposed to naturally occurring asbestos materials. These various environmental asbestos exposure pathways are poorly understood, and further studies should be pursued to evaluate their respective importance for population mesothelioma risk.

The utility of electron microscopy in detecting asbestos fibers and particles in BALF in diffuse lung diseases

Background

In patients with diffuse lung diseases, differentiating occupational lung diseases from other diseases is clinically important. However, the value of assessing asbestos and particles in bronchoalveolar lavage fluid (BALF) in diffuse lung diseases by electron microscopy (EM) remains unclear. We evaluated the utility of EM in detecting asbestos fibers and particles in patients with diffuse lung diseases.

Methods

The BALF specimens of 107 patients with diffuse lung diseases were evaluated. First, detection of asbestos by EM and light microscopy (LM) were compared. Second, the detection of asbestos using surgically obtained lung tissues of 8 of 107 patients were compared with the results of EM and LM in BALF. Third, we compared the results of mineralogical components of particles in patients with (n = 48) and without (n = 59) a history of occupational exposure to inorganic dust.

Results

BALF asbestos were detected in 11 of 48 patients with a history of occupational exposure by EM; whereas asbestos as asbestos bodies (ABs) were detected in BALF in 4 of these 11 patients by LM. Eight of 107 patients in whom lung tissue samples were surgically obtained, EM detected BALF asbestos at a level of >1,000 fibers/ml in all three patients who had ABs in lung tissue samples by LM at a level of >1,000 fibers/g. The BALF asbestos concentration by EM and in lung tissue by LM were positively correlated. The particle fractions of iron and phosphorus were increased in patients with a history of occupational exposure and both correlated with a history of occupational exposure by a multiple regression analysis.

Conclusions

EM using BALF seemed to be superior to LM using BALF and displayed a similar sensitivity to LM using surgically-obtained lung tissue samples in the detection of asbestos. Our results also suggest that detection of elements, such as iron and phosphorus in particles, is useful for evaluating occupational exposure. We conclude that the detection of asbestos and iron and phosphorus in particles in BALF by EM is very useful for the evaluation of occupational exposure.

Natural carcinogenic fiber and pleural plaques assessment in a general population: A cross-sectional study

Natural carcinogenic fibers are asbestos and asbestiform fibers present as a natural component of soils or rocks. These fibers are released into the environment resulting in exposure of the general population. Environmental contamination by fibers are those cases occurred in: rural regions of Turkey, in Mediterranean countries and in other sites of the world, including northern Europe, USA and China. Fluoro-edenite(FE) is a natural mineral species first isolated in Biancavilla, Sicily. The fibers are similar in size and morphology to some amphibolic asbestos fibers, whose inhalation can cause chronic inflammation and cancer. The aim of the current study is to assess the presence and features of pleural plaques (PPs) in Biancavilla's general population exposed to FE through a retrospective cross-sectional study. All High-Resolution Computed Tomography (HRCT) chest scans carried out between June 2009 and June 2015 in Biancavilla municipality hospital site (exposed subjects) were reviewed. The exposed groups were 1:1 subjects, matched according to age and sex distributions, with unexposed subjects (n.1.240) randomly selected among HRCT chest scans carried out in a Hospital 30km away from Biancavilla. Subjects from Biancavilla with PPs were significantly more numerous than the control group ones (218 vs 38). Average age of either group was >60 years; the age of exposed subjects was significantly (p=0.0312) lesser than the unexposed group. In exposed subjects, in most PPs thickness ranged between 2 and 4.9cm(38%, n=83); while in unexposed ones PPs thickness was less than 2cm (55%, n=21). As to the size of PPs in exposed subjects, in most cases it ranged between 1cm and 24% of chest wall (53%, n=116); while in unexposed ones the size of PPs was lesser than 1cm (23%, n=58). Among exposed subjects, 36 cases (17%) PPs were detected with calcification, whereas in unexposed ones only three (8%) presented calcification. 137 lung parenchymal abnormalities were observed in exposed group; whereas, 12 lung parenchymal involvement were registered in unexposed subjects. The RR for PPs is 6,74 CI 95% (4,47-9,58) p<0,0001 in the exposed population. These findings, suggested the urge to extend the screening on the possible involvement of the respiratory tract to all Biancavilla's population, particularly in those aged more than 30. Besides, it seems essential to start indoor monitoring Biancavilla's municipality.

Serum biomarkers in patients with mesothelioma and pleural plaques and healthy subjects exposed to naturally occurring asbestos

PURPOSE

This study investigated the diagnostic accuracy of the serum biomarkers osteopontin and mesothelin in discriminating mesothelioma patients from those with other, benign conditions and whether levels of the biomarkers differed in subjects who had inhaled naturally occurring asbestos compared with a non-exposed control group.

METHODS

This cross-sectional study studied 24 subjects with mesothelioma, 279 subjects with pleural plaques, 123 "healthy exposed," and 120 control subjects. The Kruskal-Wallis test was performed to compare mesothelin and osteopontin levels of the groups, and receiver operating characteristics curves were generated to determine diagnostic yields of both biomarkers. Multiple linear regression analyses were used to identify associated covariates with osteopontin and mesothelin levels.

RESULTS

Serum osteopontin and mesothelin levels were higher in mesothelioma than in benign asbestos-related diseases and healthy exposed subjects. Both biomarker levels were independently associated with mesothelioma, age and smoking pack years. Mesothelin levels were also associated with body mass index. The sensitivity and specificity of osteopontin in distinguishing mesothelioma from the three other groups were 75 and 86 %, respectively; those of mesothelin were 58 and 83 %, respectively. The sensitivity and specificity to discriminate mesothelioma from pleural plaques and healthy subjects were 93 and 73 %, respectively, if osteopontin and mesothelin levels were higher than their optimal cut off levels.

CONCLUSIONS

The combination of serum osteopontin and mesothelin levels can help to distinguish mesothelioma from benign asbestos-related diseases and asbestos-exposed subjects.

Is living close to ophiolites related to asbestos related diseases? Cross-sectional study

OBJECTIVE

To determine the rate of pleural plaques and malignant mesothelioma and other factors that affect people living close to ophiolites.

METHODS

The study population was comprised of 2970 volunteers who resided <10 km from an ophiolitic unit. Control group comprised of 157 residents >25 km from ophiolites. Information gathered from the patients included presence of pleural plaques on chest X-ray, distance from ophiolites, gender, smoking status, duration of asbestos exposure, and body mass index (BMI). Mineralogical analysis of soil and rock samples was performed by X-ray diffraction.

RESULTS

Among the 2970 study participants, those who lived close to ophiolites, 9.8% had asbestos related disease (3 malignant mesothelioma, 289 pleural plaques). No asbestos related disease (ARD) was identified in the control group. Male gender (OR: 2.63, 95% 1.9-3.5, p < 0.001), advanced age (5% increase for every year p < 0.001), residential proximity to ophiolites (for every 1 km proximity, a 12% increase p < 0.001), and low BMI (for every 1 unit decrease, 3.6% increase p < 0.001) were associated with increased risk of ARD.

CONCLUSION

The rate of ARD is higher in residents living close to ophiolites. Important risk factors for developing ARD were age, male gender, proximity to an ophiolite site, and low BMI.

Therapeutic antitumor efficacy of anti-epidermal growth factor receptor antibody, cetuximab, against malignant pleural mesothelioma

Epidermal growth factor receptor (EGFR) is commonly overexpressed in malignant pleural mesothelioma (MPM). Cetuximab is a chimeric mouse-human antibody targeted against EGFR and induces potent antibody-dependent cellular cytotoxicity (ADCC). The action of cetuximab against MPM cells has not been well studied. Therefore, in this study, we investigated the antitumor activity of cetuximab against MPM cell lines, particularly with respect to ADCC activity in vitro and in vivo. EGFR expression of MPM cells was measured by a quantitative flow cytometric analysis and immunohistochemistry. The effect of cetuximab on growth inhibition was assessed using a modified MTT assay. The ADCC activity was measured by a 4-h ⁵¹Cr release assay using fresh or IL-2-activated peripheral blood mononuclear cells. In vivo antitumor activity of cetuximab was evaluated using an orthotopic implantation mouse model. Cetuximab-mediated ADCC activity against MPM cells was observed at low concentration (0.25 mg/ml) and was enhanced by IL-2, whereas no direct effect on growth inhibition was detected. A logarithmic correlation was observed between the number of EGFRs on MPM cells and ADCC activity. Low EGFR expression on the MPM cells, which was weakly detectable by immunohistochemistry, was sufficient for maximum ADCC activity. In the mouse model, cetuximab treatment with or without IL-2 significantly inhibited intrathoracic tumor growth and prolonged their survival. Our study shows that cetuximab has potent anti-MPM activity both in vitro and in vivo, mainly through the immunologic mechanism of ADCC. Cetuximab has the potential to be used as a novel therapy for MPM patients.

Asbestos exposure during uncontrolled removal of sprayed-on asbestos

Asbestos-containing materials in place in buildings, especially sprayed-on asbestos, are still an important health threat. Clearance of these materials has to be operated by specifically trained workers wearing specific individual protection suits after containment of the contaminated area. Good work practices are, however, not always applied. We report the case of two workers hired for ∼1 week to remove sprayed-on amosite asbestos during the remodeling of a former industrial hall. Regulatory protective equipments were not used. A legal action was initiated after disclosure of the working conditions. Medical examinations were performed 18 and 22 months after exposure. Workers denied any other asbestos exposure. Lung function tests and chest computed tomography scans were normal. Very high levels of asbestos fibers and bodies were discovered on mineralogical analysis of bronchoalveolar lavage fluid (BALF) by phase contrast light microscopy and analytical electron microscopy. All fibers were amosite. An extrapolation considering duration of exposure, breathing pattern, and BALF fiber content suggests that the workers were exposed to airborne fiber concentrations in the range from several tens to about a hundred World Health Organization fibers per milliliter air. In conclusion, exposures to historical airborne fiber levels prevailing half a century ago may still occur today when the work regulations are not applied. In these conditions, even very short exposures may result in considerable lung fiber retention in case of amphibole exposure with the subsequent risk for developing asbestos-related diseases. Fiber analysis in BALF is useful to clarify such exposures.

Bronchoalveolar lavage fluid cellular profile in workers exposed to chrysotile asbestos

The cellular profile of bronchoalveolar lavage fluid (BALF) in asbestos-exposed population remains controversial. We, therefore, aimed to investigate BALF in apparently healthy individuals that were exposed in asbestos-related work for a long period of time. Participants were selected among employees of a car brakes and clutches factory that used chrysotile asbestos. Selection criteria were an employment history of ≥15 years and the absence of severe respiratory disease. The total number and type of BALF cells, the existence of dust cells, iron-laden macrophages and asbestos bodies were assessed. Thirty-nine workers (25 men), with a mean age of 46.2 ± 4.2 years and a mean employment time of 23.5 ± 4 years, participated. Asbestos bodies were observed in 14 out of 39 (36%) specimens, dust cells in 37 and iron-laden macrophages in all. Those with asbestos bodies had at least 3 times higher probability to have lymphocytosis (lymphocytes > 11%: 64% vs 28%, p = 0.027) and had an increased percentage of iron-laden macrophages compared to those without asbestos bodies (median values: 42% vs 13%, p = 0.08). Smokers (36%) had less lymphocytes compared to non and ex-smokers (median values: 6% vs. 13%, p = 0.002), and iron-laden macrophages count had a positive relation (r = 0.31, p = 0.05) to lymphocyte count. Asbestos-exposed asymptomatic individuals with the presence of asbestos bodies in the BALF are more likely to have lymphocytic alveolitis while concurrent dust exposure and smoking habits hold a significant role.

Endemic malignant mesothelioma: exposure to erionite is more important than genetic factors

The village of Karain, Turkey, has the world's highest prevalence rate of malignant mesothelioma (MM). Environmental exposure to erionite is thought to cause the disease. However, it has also been suggested that the disease is mainly genetic. Residents in Karain village were traced from 1990 to 2006. Mineral samples were obtained from stones used in construction of their houses and any fibers present were identified. All women who had moved to the village as brides were traced and their cause of death determined. MM was the cause of death in 52 of 322 villagers, representing 50.5% of all deaths. Only 2 of 8 types of stones used in construction contained erionite, and these stones had been used almost exclusively in the mid-sections of the village, where MM was common. In houses not containing erionite, no cases of MM were observed. Sixty-four women came as brides to Karain from villages where erionite or asbestos is not found. Of the 16 women who have died, 11 (69%) died from MM. The extreme risk of MM in Karain is due to indoor exposure to erionite. The effect of genetic factors on mesothelioma development cannot be evaluated in this study, but is likely to be minor.

The health impact of nonoccupational exposure to asbestos: what do we know?

The objective of this study was to examine the epidemiological data that confirm the risks of pleural mesothelioma, lung cancer, and other respiratory damage associated with nonoccupational exposure to asbestos, in circumstances where exposure levels are usually lower than those found in the workplace: domestic and paraoccupational exposure to asbestos-containing material among people living with asbestos workers or near asbestos mines and manufacturing plants, environmental exposure from naturally occurring asbestos in soil, and nonoccupational exposure to asbestos-containing material in buildings. Studies concerning natural asbestos in the environment show that the exposure that begins at birth does not seem to affect the duration of the latency period, but the studies do not show whether early exposure increases susceptibility; they do not suggest that susceptibility differs according to sex. Solid evidence shows an increased risk of mesothelioma among people whose exposure comes from a paraoccupational or domestic source. The risk of mesothelioma associated with exposure as result of living near an industrial asbestos source (mines, mills, asbestos processing plants) is clearly confirmed. No solid epidemiological data currently justify any judgment about the health effects associated with passive exposure in buildings containing asbestos. Most of the studies on nonoccupational sources reported mainly amphibole exposure, but it cannot be ruled out that environmental exposure to chrysotile may also cause cancer. Nonoccupational exposure to asbestos may explain approximately 20% of the mesotheliomas in industrialized countries, but it is does not seem possible to estimate the number of lung cancers caused by these circumstances of exposure.

Tumor suppressor gene alterations in patients with malignant mesothelioma due to environmental asbestos exposure in Turkey

BACKGROUND

Environmental asbestos exposure can cause the grave lung and pleura malignancies with a high mortality rate, and it is also associated with increased rate of other organ malignancies. Asbestos exposure can develop genotoxic effects and damage in the pleura and lungs.

OBJECTIVE

In this study, we aimed to determine tumor suppressor gene (TSG) loss in genomic DNA which was isolated from pleural fluid and blood samples of patients with Malignant Pleural Mesothelioma (MPM) due to environmental asbestos exposure.

DESIGN AND PATIENTS

Prospective study of period from 2001 to 2003 in 17 patients with MPM.

METHODS

A total of 12 chromosomal regions were researched by comparing genomic DNA samples isolated from blood and pleural effusion (using PCR, and polyacrylamide gel electrophoresis denaturizing), on 2 different chromosomes which have 9 different polymorphic determinants at 6q and 3 different polymorphic determinants at 9p using molecular genetic methods on 13 patients clinico-pathologically diagnosed MPM.

RESULTS

Loss of Heterozygosity (LOH) was determined at D6S275 in one patient, at D6S301 in another, at D6S474 in 2, at ARG1 in 2, at D6S1038 in 2 and at D6S1008 in 3 patients. In 7 (54%) of the 13 patients, we found LOH in at least one site. No LOH was determined at any informative loci in 6 patients. Of the 13 patients, no investigated markers were determined at 9p.

CONCLUSION

In this study, genomic DNA samples obtained from MPM patients with asbestos exposure revealed that they contained important genotoxic damage. We found no other study on this subject at molecular level in pleural effusion either in Turkey or in the Med-line literature. We believe that this study will provide important support for other research into molecular-genetic variations, both on this subject and other malignancies, and may also constitute a base for early diagnosis and gene therapy research in the future.

Respiratory health in Turkish asbestos cement workers: the role of environmental exposure

AIM

Benign and malignant pleural and lung diseases due to environmental asbestos exposure constitute an important health problem in Turkey. The country has widespread natural deposits of asbestos in rural parts of central and eastern regions. Few data exists about the respiratory health effects of occupational asbestos exposure in Turkey. A cross-sectional study was conducted to investigate respiratory health effects of occupational asbestos exposure and the contribution of environmental asbestos exposure.

METHODS

Investigations included asbestos dust measurements in the workplace and application of an interviewer-administered questionnaire, a standard posteroanterior chest X-ray and spirometry. Information on birthplace of the workers was obtained in 406 workers and used to identify environmental exposure to asbestos, through a map of geographic locations with known asbestos exposure.

RESULTS

Asbestos dust concentration in the ambient air of the work sites (fiber/ml) ranged between 0.2 and 0.76 (mean: 0.25, median: 0.22). Environmental exposure to asbestos was determined in 24.4% of the workers. After the adjustment for age, smoking, occupational asbestos exposure, and potential risk factors environmental asbestos exposure was associated with small irregular opacities grade > or = 1/0 (44.2% vs. 26.6%, P < 0.01), FVC% (97.8 vs. 104.5, P < 0.0001), and FEV1% (92.4 vs. 99.9, P < .0001). Occupational exposure to asbestos was associated with small irregular opacities grade > or = 1/0 (OR: 2.0, 95% CI: 1.3-3.1, per 1 unit increase in the natural logarithm of fiber/ml) and FEV1/FVC% (beta: 1.1, SEM: 0.54; P < 0.05, per 1 unit increase in the natural logarithm of fiber/ml).

CONCLUSIONS

Environmental exposure to asbestos could increase the risk of asbestosis and lung function impairment in workers occupationally exposed to asbestos, independent from occupational exposure and smoking.

Determination of environmental exposure to asbestos (tremolite) and mesothelioma risks in the southeastern region of Turkey

In this study, the authors examined the concentrations and mineralogical analyses of asbestos, and investigated mesothelioma risk in southeastern Anatolia, Turkey. They used a gravimetric dust sampler to collect samples from 2 villages and 2 asbestos mines (1 active). Samples were then evaluated by an X-ray diffractometer and an electron microscope. The authors found high concentrations of asbestos in an active mine (4.9 fibers[f]/cm3) and at a house that was plastered with asbestos (1.24 f/cm3) and had a very active population. They found a low concentration (0.0042 f/cm3) in indoor measurements taken in Armutova village, and an even lower concentration (0.000081 f/cm3) in the inactive mine environment. Outdoor measurements included a low concentration of 0.007 f/cm3 in the village environment, and a high concentration of 1.17 f/cm3 on the mine road during the passing of a sheep herd. The people in the region are continuously exposed to asbestos during normal activities. This cumulative exposure to asbestos carries sufficient risks for mesothelioma development.

Malignant pleural mesothelioma in Turkey, 2000–2002

Both asbestos and erionite related malignant pleural mesothelioma (MPM) is a serious health problem in Turkey. Erionite has a higher potency in the lung than asbestos and familial clustering of malignant mesothelioma suggests a genetic predisposition to this cancer among affected individuals. Neither Simian virus 40 (SV40) nor human herpes virus 8 (HHV-8) are co-factors in the pathenogenesis of environmentally induced mesothelioma. A survival advantage has been demonstrated in patients with asbestos-induced mesothelioma compared with erionite-induced mesothelioma. This together with the proliferation index (PI) can be used as an independent prognostic factor for patients with malignant pleural mesothelioma. It is envisaged that the application of these prognostic approaches together with the new TNM staging system will allow investigations to be more precisely carried out and evaluated.

Assessment of Environmental and Domestic Exposure to Tremolite in New Caledonia

In this study, the authors characterized exposure to asbestos in the population of New Caledonia, an area where a high mesothelioma incidence was found to be associated with the use of a tremolite-containing whitewash on dwellings. The authors collected airborne samples from various sources. Lung tissue samples or bronchoalveolar lavage fluids were available for 80 subjects, who were interviewed regarding their residential and occupational histories. The authors analyzed all samples by analytical transmission electron microscopy. Results indicated that the use of the tremolite-based whitewash may generate high airborne fiber levels and result in asbestos lung contents comparable with those observed in occupational settings. The highest airborne tremolite concentrations were reached during sweeping in whitewashed houses. Lung concentrations of tremolite fibers were significantly higher in subjects exposed to the whitewash than in unexposed subjects, and the concentrations increased with the duration of exposure.

Malignant mesothelioma due to environmental exposure to asbestos: follow-up of a Turkish cohort living in a rural area

STUDY OBJECTIVES

This study examines the incidence of malignant pleural mesothelioma (MPM) in a rural population of Turkey with environmental exposure to asbestos-contaminated soil mixtures (white soil).

DESIGN

A field-based epidemiologic study.

SETTING AND SUBJECTS

A cohort of villagers (the "Eskisehir" cohort) from 11 villages around Eskisehir in central Anatolia, who had been environmentally exposed to asbestos due to the use of white soil.

MEASUREMENTS

The mineral content and asbestos contamination of the white soil used in these villages was determined, as well as airborne fiber concentrations. Cohort members' details of age, sex, ambient exposure data, duration of residence in the villages, and hospital records, including pathologic diagnosis, were recorded.

RESULTS

The Eskisehir cohort consisted of 1,886 villagers. During the observation time, 377 deaths occurred and 24 MPM cases were diagnosed. Average annual mesothelioma incidence rates were 114.8/100,000 for men and 159.8/100,000 for women.

CONCLUSIONS

These data indicate that the risk of mesothelioma is 88.3 times greater in men and 799 times greater in women, respectively, in comparison to world background incidence rates.

Lung diseases due to environmental exposures to erionite and asbestos in Turkey

Asbestos deposits have been used locally by the rural inhabitants of Central and Southeastern Anatolia for domestic purposes for many years. Mineralogical analysis revealed that tremolite is the most prominent asbestos type found in the region. There is in addition another mineral fiber found particularly in three villages located in the Cappadocian region of Central Anatolia (zeolite villages). This is a non-asbestos mineral, which has been identified as the fibrous zeolite, erionite. This fiber is present in the volcanic tuffs, which are used as building stone. Hence, exposure to erionite fibers is always possible in the houses, annexes, and streets of the villages. It has been demonstrated that both asbestos and erionite cause a variety of benign and malignant chest diseases. Among the diseases, calcified pleural plaques (CPP) are the most frequently seen and may be used as an indicator of mineral fiber exposure. Asbestos and erionite exposure are the main causes of malignant mesotheliomas in Turkey. In zeolite villages malignant mesothelioma is responsible for more than 50% of the total deaths. A recent study showed that simian virus 40 is not a cofactor in the pathogenesis of environmental malignant mesothelioma in Turkey. An additional recent genetic-epidemiological study showed that there are some families, which are genetically predisposed to mesothelioma.

Prognostic significance of flow cytometric DNA analysis in patients with malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) due to environmental exposure to asbestos and erionite is a relatively common cancer in Turkey. In this study, we investigated the value of flow cytometric (FCM) DNA analysis and other prognostic factors such as age and etiologic factor in the patients with MPM, treated with surgery+/-combination chemotherapy+/-radiotherapy. A total of 40 patients with a median age of 50 (range 30-68) were included in the study. Twenty-nine patients had asbestos exposure in etiology, while 11 had fibrous zeolite (erionite). Paraffin-embedded tumor specimens were studied by FCM for DNA analysis. Twelve patients (30%) had aneuploid tumors and 28 (70%) had diploid ones. Mean S-phase fraction (SPF; %) was 9.1+/-1.1 and proliferation index (PI, SPF+G2/M phase; %) was 11.3+/-0.9. While the median overall survival (OS) was 10+/-2 months (6-14; 95% CI), 1-year survival rate was 45.2%. Only PI was found to be statistically significant for OS in univariate analysis (P=0.013). PI was also found to be an independent prognostic factor for all patients (P=0.035). Aneuploidy was significantly higher in erionite group compared with asbestos group. Male predominance and poor survival were also prominent in erionite group, though not statistically significant. In conclusion, PI is an independent prognostic factor for patients with MPM and the biologic features of the disease may show differences with respect to different etiologies.

p53, p21 and metallothionein immunoreactivities in patients with malignant pleural mesothelioma: correlations with the epidemiological features and prognosis of mesotheliomas with environmental asbestos exposure

The aim of this study is to investigate immunoreactivity for p53, p21 and metallothionein in diffuse malignant pleural mesothelioma (DMPM) and to determine the relationships between the age, sex, asbestos exposure time, survival of DMPM patients with environmental asbestos exposure and immunoreactivity to p53, p21 and metallothionein. Sixty-seven histopathologically-confirmed DMPMs, 38 of whom had environmental and 29 had occupational asbestos exposure, were included. The tumour tissue samples were immunostained with antibodies against p53, p21 and metallothionein. Epidemiological data and the survival times for the DMPM patients with environmental asbestos exposures were obtained from hospital records. Thirty-three per cent of the DMPMs were positive for p53, 35% for p21 and 52% for metallothionein. There was no statistical difference between the histological subtypes of DMPM in terms of immunoreactivity for p53, p21 and metallothionein. For p21 and metallothionein there was a statistically significant difference between the exposure characteristics: patients with environmental asbestos exposure had shown more immunopositivity. There were statistically significant differences between age groups and between asbestos exposure times for metallothionein, and between asbestos exposure times and p21. The patients with positive immunostaining had longer exposure times and were older than those having negative immunostaining. The differences between survival of the patients were not statistically significant in terms of the immunohistochemical results for p53, p21 and metallothionein.

The role of environmental and occupational exposures in Turkish immigrants with fibre-related disease

Environmental exposure to tremolite and erionite causes endemic diseases of the lung and pleura in Turkey. This study aimed to evaluate the impact of these exposures and further occupational exposures on fibre-related diseases in Turkish immigrants living in Belgium. The study included 51 males and 17 females that emigrated < 1-38 yrs ago. Most of them (n=46) had nonmalignant pleural lesions, one had asbestosis and one had mesothelioma. Environmental asbestos exposure was likely for the majority of patients (60%), but there were also reports of possible occupational asbestos (n = 14) and erionite (n = 2) exposure. Tremolite was the main fibre type in bronchoalveolar lavage fluid (BALF). Elevated concentrations of amosite or crocidolite were detected in only two patients. The delay elapsed since the end of the environmental exposure had no influence on the asbestos body or the tremolite fibre concentrations in the BALF of Turkish immigrants. Most fibre-related diseases in Turkish immigrants are probably due to environmental rather than occupational exposure. Precise information about geographical origin and occupation should be obtained when investigating these patients. Mineralogical analysis of bronchoalveolar lavage fluid gives valuable information on the type and intensity of exposure, especially in patients with both environmental and occupational exposure.

Erionite bodies and fibres in bronchoalveolar lavage fluid (BALF) of residents from Tuzköy, Cappadocia, Turkey

OBJECTIVES

The high incidence of malignant mesothelioma in some villages of Cappadocia (Turkey) is due to environmental exposure to erionite fibres. The aim was to evaluate the fibre burden in bronchoalveolar lavage fluid (BALF) from inhabitants of an erionite village and compare it with Turkish subjects with or without environmental exposure to tremolite asbestos.

METHODS

Ferruginous bodies (FBs) and fibres were measured and analyzed by light and transmission electron microscopy (TEM) in the BALF of 16 subjects originating from Tuzköy.

RESULTS

FBs were detected in the BALF of 12 subjects, with concentrations above 1 FB/ml in seven of them. Erionite was the central fibre of 95.7% of FBs. Erionite fibres were found in the BALF of all subjects, by TEM, and these fibres were low in Mg, K, and Ca compared with erionite from Tuzköy soil. The mean concentration of erionite fibres in BALF was similar to that of tremolite fibres in Turks with environmental exposure to tremolite. The proportion of fibres longer than 8 microm in BALF represented 35.6% for erionite compared with 14.0% for tremolite. The asbestos fibre concentrations in erionite villagers was not different from that in Turks without environmental exposure to tremolite.

CONCLUSION

Analysis of BALF gives information about fibre retention in populations environmentally exposed to erionite for whom data on fibre burden from lung tissue samples are scarce. This may apply to exposed Turks having emigrated to other countries.

The past and present of pneumoconioses

Pneumoconioses are still a common cause of chronic lung disease. In industrialized countries, improvements in working conditions and dust control measures have led to a decrease in the incidence of severe forms of silicosis, coal worker pneumoconiosis, and parenchymal asbestosis. However, the diversity of settings in which silica and asbestos are used fuels a continued input of cases, and the burden of cases related to remote exposures is still considerable. Overall, the clinical picture of the classic pneumoconioses and their complications has not changed substantially. However, their limits and links have expanded toward systemic and connective tissue disease, idiopathic pulmonary fibrosis, and antineutrophil cytoplasmic autoantibody-positive vasculitides. Immunologically mediated occupational lung diseases have emerged, such as berylliosis and hard-metal disease. Advances in imaging, mineralogic analysis of bronchoalveolar lavage fluid, and immunologic techniques have been instrumental in describing new patterns of disease and are helpful in litigious or difficult cases.