Metsovo lung outside Metsovo. Endemic pleural calcifications in the ophiolite belts of Greece

Review on the adverse health effects of asbestiform antigorite, a non-regulated asbestiform serpentine mineral

BACKGROUND

Although antigorite is generally described as platy, its fibrous (asbestiform) variant is present widespread in serpentinite rocks. In addition to its primarily fibrous occurrence, asbestiform antigorite may also be formed from serpentinite with massive appearance during tunneling and mining. It is not of commercial interest, but exposure may occur in the certain environments.

METHODS AND RESULTS

Detailed studies of the structural features of this antigorite type revealed characteristics closely related to those of chrysotile. Therefore, it is plausible that this serpentine mineral may present a similar health risk for exposed subjects. This is in agreement with results from clinical and animal studies, as well as in vitro experiments showing the cytotoxic, fibrogenic, and carcinogenic potential of antigorite, similar to that of chrysotile and amphibole asbestos.

CONCLUSIONS

Current evidence supports a need for an update to existing regulations to include unregulated asbestiform antigorite, similar to regulatory measures taken for asbestos.

Carving of non-asbestiform tremolite and the risk of lung cancer: a follow-up mortality study in a historical nephrite processing cohort

Objectives

The health risks associated with exposure to non-asbestiform asbestos minerals, including nephrite, are unclear. In 1965 nephrite processing began in the town of Fengtian in Taiwan, and the majority of inhabitants were involved in the industry from 1970 until 1980. The objectives of this study were to examine lung cancer deaths and assess the carcinogenic effects of nephrite carving.

Methods

We studied mortality due to lung cancer (ICD-9 code 162 for cancers of the trachea, bronchus and lung) from 1979 to 2011. We calculated the standardised mortality ratio (SMR) for lung cancer using the age- and sex-specific cancer mortality rates in eastern Taiwan as the standard rates. Air samples, bulk samples and a surface sample were analysed.

Results

Nephrite is a non-asbestiform asbestos mineral composed of microcrystalline tremolite. During nephrite processing, in personal air samples the average concentration of elongated mineral particles with the morphological characteristics of asbestos fibres was 1.4 f/cm³, with rough grinding generating the highest concentrations (4.7 f/cm³). Transmission electron microscopy (TEM) confirmed that the air samples contained intact asbestiform tremolite fibres. The ambient air samples and the wipe sample indicated paraoccupational contamination. The crude mortality rates for lung cancer were higher in Fengtian than in Taiwan for all age groups and both genders. The SMR for lung cancer was 1.28 (95% CI 1.12 to 1.45).

Conclusions

Nephrite carving may increase the risk of lung cancer. Appropriate medical monitoring is warranted for workers who are exposed to similar materials.

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.

Compensation for environmental asbestos-related diseases in South Africa: a neglected issue

Background

Environmentally acquired asbestos-related diseases (ARDs) are of concern globally. In South Africa, there is widespread contamination of the environment due to historical asbestos mining operations that were poorly regulated. Although the law makes provision for the compensation of occupationally acquired ARDs, compensation for environmentally acquired ARDs is only available through the Asbestos Relief Trust (ART) and Kgalagadi Relief Trust, both of which are administered by the ART. This study assessed ARDs and compensation outcomes of environmental claims submitted to the Trusts.

Methods

The personal details, medical diagnoses, and exposure information of all environmental claims considered by the Trusts from their inception in 2003 to April 2010 were used to calculate the numbers and proportions of ARDs and compensation awards.

Results

There were 146 environmental claimants of whom 35 (23.9%) had fibrotic pleural disease, 1 (0.7%) had lung cancer, and 77 (52.7%) had malignant mesothelioma. 53 (36.3%) claimants were compensated: 20 with fibrotic pleural disease and 33 with mesothelioma. Of the 93 (63.7%) claimants who were not compensated, 33 had no ARDs, 18 had fibrotic pleural disease, 1 had lung cancer, and 44 had mesothelioma. In addition to having ARDs, those that were compensated had qualifying domestic (33; 62.2%) or neighbourhood (20; 37.8%) exposures to asbestos. Most of the claimants who were not compensated had ARDs but their exposures did not meet the Trusts’ exposure criteria.

Conclusions

This study demonstrates the environmental impact of asbestos mining on the burden of ARDs. Mesothelioma was the most common disease diagnosed, but most cases were not compensated. This highlights that there is little redress for individuals with environmentally acquired ARDs in South Africa. To stop this ARD epidemic, there is a need for the rehabilitation of abandoned asbestos mines and the environment. These issues may not be unique to South Africa as many countries continue to mine and use asbestos.

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.

Mesothelioma mortality in Greece from 1983 to 2003

OBJECTIVE

To present summary statistics of the Greek mesothelioma epidemic including summaries by occupation and geographical area.

METHODS

The National Statistics Service provides our data, which contain all deaths from 1983 to 2003 where mesothelioma was mentioned on the death certificate.

RESULTS

The annual number of mesothelioma deaths has increased from 9 in the 3-year period of time 1983-1985 to 53 in 2001-2003. Current deaths in males account for about 72% of the cases. The area of Epirus in Greece has the highest cause-specific mortality rate over the period 1983-2003. The occupational group which is related to the higher number of mesothelioma deaths was clerks and those occupied in business; following farmers, workers-technicians and drivers.

CONCLUSION

Our data suggest a change in the balance of risk away from traditional asbestos exposure industries to industries where one could describe the exposure as secondary such as plumbers, technicians, drivers, farmers. Also, we found out that the higher cause-specific mortality rate was 0.38/100,000 population in Epirus, the lower was 0.025/100,000 in Thessalia and the national average rate was 0.10/100,000 population.

Epidemiology and Etiology of Mesothelioma

Unequivocally the history of mesothelioma parallels that of asbestos exposure. The estimation that the asbestos cancer epidemic will cause 10 million deaths past and present renders the need to reach urgently a global ban on asbestos an issue of highest priority, so that the asbestos cancer epidemic will not become more devastating and will not continue indefinitely.

Decreasing Prevalence of Pleural Calcifications Among Metsovites With Nonoccupational Asbestos Exposure

STUDY OBJECTIVES

Twenty years ago, we reported on a very high prevalence of pleural calcifications (PCs) and malignant mesothelioma among inhabitants of Metsovo, in northwestern Greece. It was shown that both abnormalities were related to asbestos exposure from a whitewash containing tremolite. The fading use of this material has resulted in a decreased incidence of mesothelioma (one third of the original incidence). The aim of the present study was to examine whether PCs among Metsovites has followed a similar trend.

DESIGN

Retrospective study.

SETTINGS

University Hospital of Ioannina, a tertiary teaching hospital, "G. Hadjikosta" Hospital, a tertiary hospital in Ioannina, and Metsovo Health Center, a primary care center in the town of Metsovo.

PATIENTS

Chest roentgenograms of 307 Metsovites, obtained between from 1998 to 2002 were examined. The prevalence of PCs was compared to the one noted 20 years ago.

RESULTS

A significantly lower prevalence of calcifications was observed now among younger Metsovites (< 60 years of age). In both studies, there was an increasing rate of PC with age.

CONCLUSIONS

The findings of the present study strengthen the incrimination of the whitewash containing tremolite in the development of PCs in Metsovites. The withdrawal of its use in the area has resulted in a null prevalence of PCs in individuals < 40 years old.

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.

Exposure to tremolite asbestos and respiratory health in Swedish dolomite workers

OBJECTIVES

Deposits of carbonate rock like limestone and dolomite may contain tremolite asbestos. This study assessed the exposure to tremolite asbestos and the respiratory health of Swedish dolomite workers.

METHODS

95% of 137 eligible workers at two dolomite producing companies completed a self administered questionnaire that included questions on respiratory symptoms and were examined with spirometry as well as chest radiography. Total exposure to dust was gravimetrically measured and the tremolite asbestos content of the dust was assessed with polarisation and phase contrast microscopy.

RESULTS

Dolomite dust concentrations were moderate (median 2.8 mg/m3) and tremolite asbestos concentrations were generally below the limit of detection (<0.03 fibres/ml). Somewhat higher values, around 0.1 fibres/ml, were obtained in manual stone sorting and bagging. Respiratory symptoms suggestive of chronic bronchitis were more related to smoking than to estimates of individual exposure to dust. The mean vital capacity was 0.2 l lower than expected after adjustment for sex, age, height, and smoking but the decline in lung function was not associated with current or cumulative exposure to dust in a clear cut way. Two definite cases of pleural plaques and one possible case of simple pneumoconiosis were noted, but the plaques could not be attributed exclusively to exposure to tremolite asbestos.

CONCLUSIONS

Dolomite mining and milling may indeed entail low levels of exposure to tremolite asbestos, but this exposure was not a strong determinant of respiratory symptoms, lung function, or pneumoconiosis in exposed Swedish workers. This was true also for dolomite dust. The hazards of exposure to tremolite asbestos may vary across deposits, however, and additional studies at other sites of carbonate rock exploitation are warranted.

Environmental asbestos exposure and malignant pleural mesothelioma

Asbestos-related benign and malignant pleural diseases are endemic in some rural parts of central Turkey because of environmental exposure to asbestos fibres. We report here epidemiological data on 113 patients with diffuse malignant pleural mesothelioma (DMPM) diagnosed in our clinic in Eskişehir, located in central Turkey. Of the 113 patients, 59 were men and 54 women (male:female ratio = 1). Ninety-seven patients (86%) had non-occupational asbestos exposure; all were living in villages. Their mean age was 56 years. As the patients had been exposed to asbestos from birth, the latency period was equivalent to the age of the patients. Twenty-eight patients (29%) had lived in villages their entire lives. The other 69 (71%) had been born in a village but migrated to the city or had given up white-soil usage for various reasons. The mean exposure time was 55 years for those with a long exposure period and 25 years for those with a short exposure period, but there was no significant difference between the age of the disease appearance for both groups (55 and 56 years, respectively). Thus, the latency time of mesothelioma due to environmental exposure to asbestos was longer than that due to occupational exposure, but independent of the length of exposure. Soil samples from 67 villages were analysed, comprising a population of 10,120 villagers. Tremolite and some other types of asbestos were found. In conclusion, DMPM in our region is due to mainly to environmental exposure to asbestos. The risk is substantial as a large proportion of the villagers are exposed. After smoking, asbestos exposure is one of the most serious health hazards in our rural population.

Environmental exposure to tremolite asbestos: pleural mesothelioma in two Turkish workers in Germany

This report concerns two Turkish immigrant workers, aged 50 and 59, who developed histologically confirmed diffuse malignant mesothelioma in the absence of obvious occupational exposure to asbestos in Germany. Both patients had spent their childhood in central Anatolia, Turkey, where the presence of tremolite asbestos in the environment has been described. In both patients, the lung-dust burden showed a high concentration of amphibole fibers (186 x 10(6) resp. 59 x 10(6) per gram dry tissue), mainly classified as actionolite/tremolite fibers in scanning transmission electron microscopy. In both patients, the disease was thus attributed to early environmental exposure to tremolite asbestos.

Round atelectasis and Metsovo lung

Round (helical) atelectasis is one of the benign sequelae of occupational asbestos exposure. Environmental asbestos exposure does not differ from occupational in its pleural manifestations, but to our knowledge, round atelectasis has not been reported yet. In the present study, we present the clinical and radiologic findings of five individuals with round atelectasis. They were all born in the Metsovo area, northwest Greece, where environmental exposure to asbestos (tremolite) has been documented. All five had negative evaluation for malignancy. In addition, they have been followed up for one to four years and four of them are in good health, thus confirming round atelectasis as a benign, nonpremalignant condition. The fifth patient died of malignant pleural mesothelioma two years later, while the previously detected round atelectasis remained unchanged. We therefore consider that his mesothelioma was not related to the round atelectasis, although both were certainly related to the same environmental asbestos exposure.

Malignant pleural mesothelioma due to environmental mineral fiber exposure in Turkey. Analysis of 135 cases

We reviewed data from 135 patients with environment-associated malignant pleural mesothelioma (MPM) from the Central Anatolian region of Turkey. The most significant factors suggesting the diagnosis of MPM were the village where the patient resided and the typical presenting symptoms and signs of unilateral exudative pleural effusion associated with nonpleuritic chest pain. Computed tomography and ultrasonography were very useful for evaluating the extension of the tumor in the thoracic and abdominal cavities and chest wall. The tissue diagnosis was established by either thoracoscopy (39 percent) or pleural biopsy (39 percent) in the majority of the cases. The median survival after diagnosis was 13.52 months for erionite-associated MPM and 21.56 months for asbestos-associated MPM. The actuarial survival curves for the fibrous minerals were significantly different for survival computed both from onset of the symptoms and after diagnosis. Medical or surgical treatment or both did not change the outcome of the disease.