Asbestos-related occupational lung diseases in NSW, Australia and potential exposure of the general population

A Narrative Review-Management of Malignant Pleural Effusion Related to Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is an aggressive, almost universally fatal cancer with limited therapeutic options. Despite efforts, a real breakthrough in treatment and outcomes has been elusive. Pleural effusion with significant breathlessness and pain is the most typical presentation of individuals with MPM. Although thoracentesis provides relief of breathlessness, most such pleural effusions recur rapidly, and a definitive procedure is often required to prevent a recurrence. Unfortunately, the optimal treatment modality for individuals with recurrent MPM-related effusion is unclear, and considerable variation exists in practice. In addition, non-expandable lung is common in pleural effusions due to MPM and makes effective palliation of symptoms more difficult. This review delves into the latest advances in the available management options (both surgical and non-surgical) for dealing with pleural effusion and non-expandable lung related to MPM. We discuss factors that determine the choice of definitive procedures that need to be tailored to the individual patient.

Variations in mesothelioma mortality rates among migrants to Australia and Australian-born

BACKGROUND

Australia's use and consumption of asbestos occurred at the same time as its immigration boom. Our objective was to investigate mesothelioma death rates among migrants and Australian-born between 1981 and 2012.

METHODS

Australian national mesothelioma deaths from 1981 to 2002 and 2006 to 2012 together with national censuses from 1981 to 2011 were extracted and combined. Directly standardised rates and negative binomial regression were applied examining differences in mesothelioma death rates with regard to country of birth.

RESULTS

Migrants from the UK and Ireland, Italy and Germany had significantly higher mesothelioma death rates than Australian-born; lower rates were observed among migrants from other countries.

CONCLUSIONS

Our findings suggest there may have been differences in occupational health and safety between foreign and Australian-born. Because of changes in the demographics of migrants to Australia since the 1970s and changes in occupational circumstances over time, further comparisons of occupational-related health outcomes between foreign and Australian-born could identify potential occupational inequalities that may still exist today.

Current and future risks of asbestos exposure in the Australian community

BACKGROUND

Australia mined asbestos for more than 100 years and manufactured and imported asbestos products. There is a legacy of in situ asbestos throughout the built environment.

METHODS

The aim of this study was to identify the possible sources of current and future asbestos exposure from the built environment. Telephone interviews with environmental health officers, asbestos removalists, and asbestos assessors in Australia sought information about common asbestos scenarios encountered.

RESULTS

There is a considerable amount of asbestos remaining in situ in the Australian built environment. Potential current and future sources of asbestos exposure to the public are from asbestos-containing roofs and fences, unsafe asbestos removal practices, do-it-yourself home renovations and illegal dumping.

CONCLUSION

This research has highlighted a need for consistent approaches in the regulation and enforcement of safe practices for the management and removal of asbestos to ensure that in situ asbestos in the built environment is managed appropriately.

Study on genotoxicity, oxidative stress biomarkers and clinical symptoms in workers of an asbestos-cement factory

The purpose of the present study was to investigate whether the markers of oxidative stress could be altered in workers exposed to asbestos. A comparative cross-sectional research was conducted in a group of 50 subjects exposed to asbestos and another group of 50 with the same age and sex unexposed to asbestos. Malondialdehyde (MDA), total thiol molecule (TTM), total antioxidant capacity (TAC), and DNA damage, were measured in the blood samples of workers and controls. Compared to the control group, the workers showed higher blood levels of DNA damage (P=0.0001) and MDA (P=0.0001). The workers showed lower TTM (P=0.02) as compared with the control group. There was no considerable difference on the level of TAC (P=0.1) between the groups. The workers indicated clinical symptoms such as breathlessness, phlegm, coughing and wheezing. There was a positive correlation between levels of 8-OHdG and MDA of asbestos workers and the smoking status suggesting the negative role of smoking.

Physical activity in people with asbestos related pleural disease and dust-related interstitial lung disease: An observational study

This study aimed to measure the levels of physical activity (PA) in people with dust-related pleural and interstitial lung diseases and to compare these levels of PA to a healthy population. There is limited data on PA in this patient population and no previous studies have compared PA in people with dust-related respiratory diseases to a healthy control group. Participants with a diagnosis of a dust-related respiratory disease including asbestosis and asbestos related pleural disease (ARPD) and a healthy age- and gender-matched population wore the SenseWear(®) Pro3 armband for 9 days. Six-minute walk distance, Medical Outcomes Study 36-item short-form health survey and the Hospital Anxiety and Depression Scale were also measured. Fifty participants were recruited and 46 completed the study; 22 with ARPD, 10 with dust-related interstitial lung disease (ILD) and 14 healthy age-matched participants. The mean (standard deviation) steps/day were 6097 (1939) steps/day for dust-related ILD, 9150 (3392) steps/day for ARPD and 10,630 (3465) steps/day for healthy participants. Compared with the healthy participants, dust-related ILD participants were significantly less active as measured by steps/day ((mean difference 4533 steps/day (95% confidence interval (CI): 1888-7178)) and energy expenditure, ((mean difference 512 calories (95% CI: 196-827)) and spent significantly less time engaging in moderate, vigorous or very vigorous activities (i.e. >3 metabolic equivalents; mean difference 1.2 hours/day (95% CI: 0.4-2.0)). There were no differences in levels of PA between healthy participants and those with ARPD. PA was reduced in people with dust-related ILD but not those with ARPD when compared with healthy age and gender-matched individuals.

Loss of miR-223 and JNK Signaling Contribute to Elevated Stathmin in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is often fatal, and studies have revealed that aberrant miRNAs contribute to MPM development and aggressiveness. Here, a screen of miRNAs identified reduced levels of miR-223 in MPM patient specimens. Interestingly, miR-223 targets Stathmin (STMN1), a microtubule regulator that has been associated with MPM. However, whether miR-223 regulates STMN1 in MPM and the functions of miR-223 and STMN1 in this disease are yet to be determined. STMN1 is also regulated by c-Jun N-terminal kinase (JNK) signaling, but whether this occurs in MPM and whether miR-223 plays a role are unknown. The relationship between STMN1, miR-223, and JNK was assessed using MPM cell lines, cells from pleural effusions, and MPM tissue. Evidence indicates that miR-223 is decreased in all MPM tissue compared with normal/healthy tissue. Conversely, STMN1 expression was higher in MPM cell lines when compared with primary mesothelial cell controls. Following overexpression of miR-223 in MPM cell lines, STMN1 levels were reduced, cell motility was inhibited, and tubulin acetylation induced. Knockdown of STMN1 using siRNAs led to inhibition of MPM cell proliferation and motility. Finally, miR-223 levels increased while STMN1 was reduced following the re-expression of the JNK isoforms in JNK-null murine embryonic fibroblasts, and STMN1 was reduced in MPM cell lines following the activation of JNK signaling.

IMPLICATIONS

miR-223 regulates STMN1 in MPM, and both are in turn regulated by the JNK signaling pathway. As such, miR-223 and STMN1 play an important role in regulating MPM cell motility and may be therapeutic targets.

Exercise training for asbestos-related and other dust-related respiratory diseases: a randomised controlled trial

Background

The study aimed to determine the short and long-term effects of exercise training on exercise capacity and health-related quality of life (HRQoL) compared to usual care in people with dust-related pleural and interstitial respiratory diseases. No previous studies have specifically evaluated exercise training in this patient population.

Methods

Participants with a diagnosis of a dust-related respiratory disease including asbestosis and asbestos related pleural disease were recruited and randomised to an eight-week exercise training group (EG) or a control group (CG) of usual care. Six-minute walk distance (6MWD), St George’s Respiratory Questionnaire (SGRQ) and Chronic Respiratory Disease Questionnaire (CRQ) were measured at baseline, eight weeks and 26 weeks by an assessor blinded to group allocation.

Results

Thirty-three of 35 male participants completed the study. Sixty-nine percent of participants had asbestos related pleural disease. At eight weeks, compared to the CG, the EG showed a significantly increased 6MWD (mean difference (95%CI)) 53 metres (32 to 74), improved SGRQ total score, -7 points (-13 to -1) and increased CRQ total score, 6.4 points (2.1 to 10.7). At 26 weeks significant between-group differences were maintained in 6MWD, 45 metres (17 to 73) and CRQ total score, 13.1 points (5.2 to 20.9).

Conclusion

Exercise training improved short and long-term exercise capacity and HRQoL in people with dust-related pleural and interstitial respiratory diseases.

Clinical trial registration number

ANZCTR12608000147381. Date trial registered: 27.03.2008.

Awareness of Asbestos and Action Plans for Its Exposure can Help Lives Exposed to Asbestos

Despite the fact that asbestos is a known carcinogen to humans, it is still used in industrialized countries, especially Asian countries. The global incidence of asbestos-related diseases (ARDs) due to the past use of asbestos, continues to increase, although many countries have adopted a total ban on asbestos use. The implementation of effective strategies to eliminate ARDs is therefore an important challenge in Asia, where asbestos is still mined and consumed. Collaborative efforts and strategies at the local and international levels are vital, in the pursuit toward the elimination of ARDs in this region.

Functional exercise capacity and health-related quality of life in people with asbestos related pleural disease: an observational study

BACKGROUND

Functional exercise capacity in people with asbestos related pleural disease (ARPD) is unknown and there are no data on health-related quality of life (HRQoL). The primary aims were to determine whether functional exercise capacity and HRQoL were reduced in people with ARPD. The secondary aim was to determine whether functional exercise capacity was related to peak exercise capacity, HRQoL, physical activity or respiratory function.

METHODS

In participants with ARPD, exercise capacity was measured by the six-minute walk test (6MWT) and incremental cycle test (ICT); HRQoL by the St George's Respiratory Questionnaire and physical activity by an activity monitor worn for one week. Participants also underwent lung function testing.

RESULTS

25 males completed the study with a mean (SD) age of 71 (6) years, FVC 82 (19)% predicted, FEV1/FVC 66 (11)%, TLC 80 (19)% predicted and DLCO 59 (13)% predicted. Participants had reduced exercise capacity demonstrated by six-minute walk distance (6MWD) of 76 (11)% predicted and peak work rate of 71 (21)% predicted. HRQoL was also reduced. The 6MWD correlated with peak work rate (r=0.58, p=0.002), St George's Respiratory Questionnaire Total score (r=-0.57, p=0.003), metabolic equivalents from the activity monitor (r=0.45, p<0.05), and FVC % predicted (r=0.52, p<0.01).

CONCLUSIONS

People with ARPD have reduced exercise capacity and HRQoL. The 6MWT may be a useful surrogate measure of peak exercise capacity and physical activity levels in the absence of cardiopulmonary exercise testing and activity monitors.

TRIAL REGISTRATION

ANZCTR12608000147381.

Meeting report: mode(s) of action of asbestos and related mineral fibers

BACKGROUND

Although asbestos in general is well known to cause a range of neoplastic and non-neoplastic human health effects, not all asbestos fiber types have the same disease-causing potential, and the mode of action (MOA) of specific types of asbestos and related fibers for various health outcomes are not well understood.

OBJECTIVES

A workshop was held to discuss the state of the science of the MOA for asbestos-related disease. The objective was to review the range of asbestos-induced health effects (including those at sites remote to the respiratory tract). We sought to identify existing knowledge gaps and define what research is needed to address these gaps and advance asbestos research.

DISCUSSION

Discussions centered on areas of uncertainty in the field, including the ways asbestos is defined and characterized, the role of different fiber characteristics (e.g., length and mineralogy) in disease, and the impact of low-dose exposures on human health. Studying the dosimetry and mode of action of multiple fiber types would enhance our understanding of asbestos-related disease. To better elucidate the MOA of specific asbestos fibers, the risk assessor requires data as to specific characteristics of asbestos in determining fiber toxicity (e.g., surface area, mineral type), which may inform efforts to assess and control exposures and prevent adverse human health outcomes for the diverse range of fiber types. Specific research aims were defined for these topics and for overarching issues to be addressed, including the use of standardized terminology, test materials, and better experimental models to aid in data extrapolation to humans.

CONCLUSION

To resolve these and other issues, participants agreed that diverse scientific disciplines must coordinate to better understand the MOA leading to the various asbestos-related disease end points.

A current global view of environmental and occupational cancers

This review is focused on current information of avoidable environmental pollution and occupational exposure as causes of cancer. Approximately 2% to 8% of all cancers are thought to be due to occupation. In addition, occupational and environmental cancers have their own characteristics, e.g., specific chemicals and cancers, multiple factors, multiple causation and interaction, or latency period. Concerning carcinogens, asbestos/silica/wood dust, soot/polycyclic aromatic hydrocarbons [benzo(a) pyrene], heavy metals (arsenic, chromium, nickel), aromatic amines (4-aminobiphenyl, benzidine), organic solvents (benzene or vinyl chloride), radiation/radon, or indoor pollutants (formaldehyde, tobacco smoking) are mentioned with their specific cancers, e.g., lung, skin, and bladder cancers, mesothelioma or leukemia, and exposure routes, rubber or pigment manufacturing, textile, painting, insulation, mining, and so on. In addition, nanoparticles, electromagnetic waves, and climate changes are suspected as future carcinogenic sources. Moreover, the aspects of environmental and occupational cancers are quite different between developing and developed countries. The recent follow-up of occupational cancers in Nordic countries shows a good example for developed countries. On the other hand, newly industrializing countries face an increased burden of occupational and environmental cancers. Developing countries are particularly suffering from preventable cancers in mining, agriculture, or industries without proper implication of safety regulations. Therefore, industrialized countries are expected to educate and provide support for developing countries. In addition, citizens can encounter new environmental and occupational carcinogen nominators such as nanomaterials, electromagnetic wave, and climate exchanges. As their carcinogenicity or involvement in carcinogenesis is not clearly unknown, proper consideration for them should be taken into account. For these purposes, new technologies with a balance of environment and gene are required. Currently, various approaches with advanced technologies--genomics, exposomics, etc.--have accelerated development of new biomarkers for biological monitoring of occupational and environmental carcinogens. These advanced approaches are promising to improve quality of life and to prevent occupational and environmental cancers.

Syntenic relationships between genomic profiles of fiber-induced murine and human malignant mesothelioma

Malignant mesothelioma (MM) is an aggressive tumor with a poor prognosis mainly linked to past asbestos exposure. Murine models of MM based on fiber exposure have been developed to elucidate the mechanism of mesothelioma formation. Genomic alterations in murine MM have now been partially characterized. To gain insight into the pathophysiology of mesothelioma, 16 murine and 35 human mesotheliomas were characterized by array-comparative genomic hybridization and were screened for common genomic alterations. Alteration of the 9p21 human region, often by biallelic deletion, was the most frequent alteration in both species, in agreement with the CDKN2A/CDKN2B locus deletion in human disease and murine models. Other shared aberrations were losses of 1p36.3-p35 and 13q14-q33 and gains of 5p15.3-p13 regions. However, some differences were noted, such as absence of recurrent alterations in mouse regions corresponding to human chromosome 22. Comparison between altered recurrent regions in asbestos-exposed and non-asbestos-exposed patients showed a significant difference in the 14q11.2-q21 region, which was also lost in fiber-induced murine mesothelioma. A correlation was also demonstrated between genomic instability and tumorigenicity of human mesothelioma xenografts in nude mice. Overall, these data show similarities between murine and human disease, and contribute to the understanding of the influence of fibers in the pathogenesis of mesothelioma and validation of the murine model for preclinical testing.

Breath analysis in asbestos-related disorders: a review of the literature and potential future applications

Asbestos usage was very common worldwide in the last century and continues in several countries today. Several diseases occur due to asbestos exposure, including malignant tumours such as malignant mesothelioma of the pleura and lung cancer, which have a very poor prognosis. Asbestos inhalation may also result in more benign conditions such as asbestosis (or pulmonary fibrosis due to asbestos), pleural plaques and pleural thickening. It is predicted that asbestos-associated mortality and morbidity will continue to increase, but methods for diagnosing asbestos-related disease are currently invasive and unsuitable for an increasingly elderly population. New non-invasive methods such as analysis of exhaled breath biomarkers e.g. exhaled nitric oxide (F(E)NO), exhaled breath condensate or of exhaled volatile organic compounds could potentially be extremely useful in these conditions. This article reviews the current literature on this topic and suggests areas for their application in the future.

Surveillance of Australian workplace Based Respiratory Events (SABRE) in New South Wales

BACKGROUND

The Surveillance of Australian workplace Based Respiratory Events (SABRE) New South Wales (NSW) scheme is a voluntary notification scheme established to determine the incidence of occupational lung diseases in NSW Australia.

AIMS

Data presented in this paper summarize the last 7 years of reporting to SABRE (June 2001 to December 2008).

METHODS

Every 2 months, participating occupational physicians, respiratory physicians and general practitioners (accredited by the NSW WorkCover Authority) reported new cases of occupational lung disease seen in their practices. Data collected include gender, age, causal agent and the occupations and industries believed responsible. Estimated incidence was calculated for each disease.

RESULTS

Three thousand six hundred and fifty-four cases were notified to the scheme, consisting of 3856 diagnoses. Most of the cases were males (76%). Pleural plaques [1218 (28%)] were the most frequently reported condition, followed by mesothelioma [919 (24%)]. Silicosis [90 (2%)] and occupational asthma [OA; 89 (2%)] were the most frequently reported non-asbestos-related diseases. Estimated rates for mesothelioma, diffuse pleural thickening (DPT) and OA were 83, 83 and 5 cases per million employed males per year, respectively. Trades such as carpenters and electricians associated with the building industry, electricity supply and asbestos product manufacture were the most common occupations and industries reported.

CONCLUSIONS

Asbestos-related diseases are the most frequently reported conditions to SABRE NSW. The very low incidence of OA for NSW most likely reflects under-diagnosis as well as under-reporting. Occupational lung disease is still occurring in NSW despite current preventative strategies. The SABRE scheme currently provides the only available information in this area.

Mesothelioma: Do asbestos and carbon nanotubes pose the same health risk?

Carbon nanotubes (CNTs), the product of new technology, may be used in a wide range of applications. Because they present similarities to asbestos fibres in terms of their shape and size, it is legitimate to raise the question of their safety for human health. Recent animal and cellular studies suggest that CNTs elicit tissue and cell responses similar to those observed with asbestos fibres, which increases concern about the adverse biological effects of CNTs. While asbestos fibres' mechanisms of action are not fully understood, sufficient results are available to develop hypotheses about the significant factors underlying their damaging effects. This review will summarize the current state of knowledge about the biological effects of CNTs and will discuss to what extent they present similarities to those of asbestos fibres. Finally, the characteristics of asbestos known to be associated with toxicity will be analyzed to address the possible impact of CNTs.