Medical monitoring of asbestos-exposed workers: experience from Poland

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.

Asbestiform Amphiboles and Cleavage Fragments Analogues: Overview of Critical Dimensions, Aspect Ratios, Exposure and Health Effects

The term asbestos refers to a group of serpentine (chrysotile) and amphibole (amosite, crocidolite, anthophyllite, tremolite and actinolite) minerals with a fibrous habit. Their chemical-physical properties make them one of the most important inorganic materials for industrial purposes and technological applications. However, the extraction, use and marketing of these minerals have been prohibited due to proven harmful effects, mainly involving the respiratory system. In addition to the known six minerals classified as asbestos, the natural amphiboles and serpentine polymorphs antigorite and lizardite, despite having the same composition of asbestos, do not have the same morphology. These minerals develop chemical and geometric (length > 5 μm, width < 3 μm and length: diameter > 3:1), but not morphological, analogies with asbestos, which is regulated by the WHO. The debate about their potential hazardous properties is open and ongoing; therefore, their morphological characterization has a key role in establishing a reliable asbestos hazard scenario. This review focuses on evaluating the most relevant papers, evidencing the need for a reappraisal. Different in vitro, in vivo and epidemiological studies report information about cleavage fragments with critical dimensions similar to asbestos fibres, but very few works target fragments below 5 µm in length. Breathable smaller fibres could have deleterious effects on human health and cannot be disregarded from the risk assessment process. Furthermore, a few studies suggest that the carcinogenic nature of short fibres is not excluded. This review highlights that it is worth investigating the effects of this size range of elongated mineral particles and fibres.

Characterization of Demolition Construction Waste Containing Asbestos, and the Release of Fibrous Dust Particles

This paper focuses on the characterization of demolition construction waste containing asbestos fibers and the monitoring of fibrous dust released from asbestos–cement products (ACPs) during their removal from a three-story industrial building. Asbestos-containing products removal was carried out according to a demolition management system in terms of protection of workers. The results of a chemical analysis, X-ray diffraction analysis, infrared analysis and scanning electron microscopy of demolition waste samples confirmed the same material quality of asbestos–cement (AC) elements used throughout the building. In addition, a MgO/SiO2 ratio corresponding to a serpentine silicate mineral of chrysotile was detected by means of X-ray fluorescence analysis. Also, crystalline phase calcium silicates and calcium carbonates from the cement matrix were identified in the AC waste. The relatively large differences in the elemental analysis between the sample area and the individual points found by energy-dispersive X-ray spectroscopic mapping are related to the composition heterogeneity. The highest content of magnesium occurs where asbestos fibers predominate in the cement matrix. The measured number concentrations of asbestos fibers before, during, and after asbestos–cement products removal were compared to outdoor concentrations. Indoor concentrations of asbestos fibers during the removal of AC materials did not exceed the permissible limit for a working environment (1000 fibers per one m3), except in three spots out of all the working sites inside the building. A relationship between the number and mass concentrations of asbestos dust is shown.

Comment on Małgorzata Krówczyńska and Ewa Wilk. Environmental and Occupational Exposure to Asbestos as a Result of Consumption and Use in Poland. Int. J. Environ. Res. Public Health 2019, 16, 2611

Krówczyńska M [...].

Environmental and Occupational Exposure to Asbestos as a Result of Consumption and Use in Poland

Asbestos is harmful to human health; exposure to asbestos causes a wide range of asbestos-related diseases.

AIM

Malignant mesothelioma (MM) is unique to occupational and environmental asbestos exposure.

METHODS

Environmental asbestos exposure was examined in relation to asbestos use and manufacturing, the quantity of the asbestos-containing products still in use, the concentrations of asbestos fibres in the air and the number of MM cases diagnosed each year per county.

RESULTS

The correlation coefficient of the measurements of the asbestos fibre concentrations in the air and the quantity of asbestos-cement products in use is high and amounts to 0.68. Meanwhile, the correlation coefficient of the measurements of asbestos fibre concentrations in air and MM morbidity rate resulting from environmental exposure calculated for particular counties in provinces is low and amounts to 0.37. The highest MM morbidity rate was observed for Małopolskie and Śląskie, a typical industrial area of Poland.

CONCLUSIONS

There are MM cases which are still attributable to occupational asbestos exposure, although MM cases resulting from environmental exposure to asbestos have an increased MM risk. Poland is among those countries with a low MM incidence rate, which seems to be an underestimation of environmental asbestos exposure. As long as asbestos-cement products are used in the environment, actions should be undertaken to protect public health.

Impact of low-dose computed tomography screening on lung cancer mortality among asbestos-exposed workers

Background

We previously showed that low-dose computed tomography (LDCT) screening in asbestos-exposed workers is effective in detecting lung cancer (LC) at an early stage. Here, we evaluate whether LDCT screening could reduce mortality from LC in such a high-risk population.

Methods

Within a cohort of 2433 asbestos-exposed men enrolled in an Occupational Health surveillance programme, we compared mortality between the participants in the ATOM002 study (LDCT-P, N  =  926) and contemporary non-participants (LDCT-NP, N  =  1507). We estimated standardized mortality ratios for the LDCT-P and LDCT-NP populations using regional and national rates (SMR_FVG and SMR_ITA, respectively). We compared survival for all causes, all neoplasms, LC and malignant neoplasm of pleura (MNP) between LDCT-P and LDCT-NP using Cox proportional hazard models adjusted for age, smoking history, asbestos exposure level and comorbidities.

Results

A reduction in mortality from LC was observed in the LDCT-P group compared with regional and national figures (SMR_FVG  =  0.55, 95% confidence interval (CI) 0.24-1.09; SMR_ITA  =  0.51, 95% CI 0.22-1.01); this was not the case for the LDCT-NP group (SMR_FVG  =  2.07, 95% CI 1.53-2.73; SMR_ITA  =  1.98, 95% CI 1.47-2.61). A strong reduction in LC mortality was observed for the LDCT-P compared with the LDCT-NP [hazard ratio (HR)  =  0.41, 95% CI 0.17-0.96]. Mortality was also reduced for all causes (HR  =  0.61, 95% CI 0.44-0.84), but not for all neoplasms (HR  =  0.97, 95% CI 0.62-1.50) and MNP (HR  =  0.86, 95% CI 0.31-2.41) within the LDCT-P population.

Conclusions

In our cohort, participation in the LDCT screening study was associated with reduced mortality from LC. This finding supports the use of LDCT in surveillance programmes for asbestos-exposed workers.

Airborne asbestos fibres monitoring in tunnel excavation

Tunnelling across ophiolitic formation with Naturally Occurring Asbestos (NOA) can release fibres into the environment, exposing workers, and the population, if fibres spread outside the tunnel, leading to increased risk of developing asbestos-related disease. Therefore, a careful plan of environmental monitoring is carried out during Terzo Valico tunnel excavation. In the present study, data of 1571 samples of airborne dust, collected between 2014 and 2016 inside the tunnels, and analyzed by SEM-EDS for quantification of workers exposure, are discussed. In particular, the engineering and monitoring management of 100 m tunnelling excavation across a serpentinite lens (Cravasco adit), intercalated within calcschists, is reported. At this chrysotile occurrence, 84% of 128 analyzed samples (from the zone closer to the front rock) were above 2 ff/l. However, thanks to safety measures implemented and tunnel compartmentation in zones, the asbestos fibre concentration did not exceed the Italian standard of occupational exposure (100 ff/l) and 100% of samples collected in the outdoor square were below 1 ff/l. During excavation under normal working conditions, asbestos concentrations were below 2 ff/l in 97.4% of the 668 analyzed samples. Our results showed that air monitoring can objectively confirm the presence of asbestos minerals at a rock front in relative short time and provide information about the nature of the lithology at the front. The present dataset, the engineering measures described and the operative conclusions are liable to support the improvement of legislation on workers exposure to asbestos referred to the tunnelling sector, lacking at present.

Spirometry: a predictor of lung cancer among asbestos workers

OBJECTIVE

The significance of lung function as an independent risk factor for lung cancer remains unclear. The objective of the study is to answer the question if spirometry can identify patients at risk for lung cancer among people occupationally exposed to asbestos dust in the past.

METHODS

In order to identify a group of individuals with the highest risk of lung cancer incidence based on lung function levels of FEV₁% predicted value, we examined 6882 subjects enrolled in the health surveillance program for asbestos related diseases over the years 2000-2014. We found a total of 110 cases confirmed as primary lung cancer.

RESULTS

Using Cox's proportional hazards model after adjustment for age, gender, number of cigarettes, duration of smoking and cumulative asbestos exposure, we estimated that compared with the subjects with FEV₁ ≥90% pred, the HR of lung cancer was 1.40 (95%CI: 0.94-2.08) for the subjects with FEV₁ less than 90% and 1.95 (HR = 1.86; 95%CI: 1.12-3.08) for those with FEV₁ less than 70%. In addition, probability of the occurrence of lung cancer for FEV₁ <90% of the predicted value was HR = 2.19 (95%CI: 1.04-4.61) in the subjects whose time since spirometry and cancer diagnosis was three years or less.

CONCLUSIONS

The results strongly support the hypothesis that spirometry can identify patients at a risk of lung cancer development. Regular spirometry should be offered to all patients with a history of asbestos exposure, at least once every three years.