Ecological association between asbestos-related diseases and historical asbestos consumption: an international analysis

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.

Mesothelioma incidence in 50 states and the District of Columbia, United States, 2003-2008

BACKGROUND

The decline in asbestos use in the United States may impact mesothelioma incidence.

OBJECTIVE

This report provides national and state-specific estimates of mesothelioma incidence in the United States using cancer surveillance data for the entire US population.

METHODS

Data from the National Program for Cancer Registries and the Surveillance, Epidemiology, and End Results program were used to calculate incidence rates and annual percent change.

RESULTS

During 2003-2008, an average of 1.05 mesothelioma cases per 100 000 persons were diagnosed annually in the United States; the number of cases diagnosed each year remained level, whereas rates decreased among men and were stable among women.

CONCLUSION

US population-based cancer registry data can be used to determine the burden of mesothelioma and track its decline. Even 30 years after peak asbestos use in the United States, 3200 mesothelioma cases are diagnosed annually, showing that the US population is still at risk.

New perspectives in nanomedicine

Recent advances in nanotechnology have revolutionised all aspects of life, from engineering to cosmetics. One of the most exciting areas of development is that of nanomedicine. Due to their size (less than 100nm in one aspect), nanoparticles exhibit properties that are unlike that of the same material in bulk size. These unique properties are being exploited to create new diagnostics and therapeutics for application in a broad spectrum of organ systems. Indeed, nanoparticles are already being developed as effective carriers of drugs to target regions of the body that were previously hard to access using traditional drug formulation methods. However, in addition to their role as a vehicle for drug delivery, nanoparticles themselves have the potential to have therapeutic benefit. Through manipulation of their elemental composition, size, shape, charge and surface modification or functionalisation it may be possible to target particles to specific organs where they may elicit their therapeutic effect. In this review we will focus on the recent advances in nanotechnology for therapeutic applications with a particular focus on the respiratory system, cancer and vaccinations. In addition we will also address developments in the field of nanotoxicology and the need for concomitant studies in to the toxicity of emerging nanotechnologies. It is possible that the very properties that make nanoparticles a desirable technology for therapeutic intervention may also lead to adverse health effects. It is thus important to determine, and appreciate, the fine balance between the efficacy and toxicity of nanomedicine.

Malignant mesothelioma in Eastern Asia

Relatively low numbers of malignant mesotheliomas have been reported from Eastern Asia. In order to explore the causes of this fact, the available data on mesothelioma incidence/mortality in five countries (Japan, South Korea, Taiwan, Hong Kong, and Singapore) were reviewed. Data on the industrial histories of the above countries were also examined. Mesothelioma incidence was low, despite a history of high shipbuilding and port activities, in which heavy exposure to asbestos generally has occurred. Underestimation of mesothelioma could partly explain the above discrepancy. Moreover, in some areas a sufficient latency period for mesothelioma development may have not yet elapsed, due to recent industrialization. However, other possibilities have to be considered. The cancer epidemiology in Eastern Asia differs deeply from that seen in Western countries, an indication of differences in etiologic factors of cancer as well as in co-factors. In addition, the oncogenic spectrum of asbestos is wide, and not completely defined. In a very different milieu from that of Western countries, asbestos could preferentially hit targets other than serosal membranes.

Gene therapy for malignant mesothelioma: current prospects and challenges

Malignant mesothelioma, developed in the thoracic cavity, is resistant to current treatments. Suppression of the local tumor growth is beneficial to the patients since mesothelioma infrequently metastasizes to extrapleural organs. A majority of the tumors have a homologous genetic deletion at the INK4A/ARF locus that includes the p14ARF and the p16INK4A genes, and the genetic defect results in an inactivation of the p53-mediated pathways and in progression of cell cycle through pRb phosphorylation. Preclinical studies targeting the genetic abnormality with adenoviruses showed that restoration of the p53 pathways induced pRb dephosphorylation and subsequently produced anti-tumor effects. A number of preclinical studies with different genes and vector systems demonstrated the therapeutic efficacy and raised the possibility of gene therapy in clinical settings. An intrapleural administration of vectors has several advantages in transducing pleural mesothelioma but activates rapid antibody production which impedes further gene expression. There have been several clinical studies conducted for mesothelioma and these trials showed the feasibility of intrapleural administrations of adenovirus vectors. In this review we summarize major preclinical and clinical gene therapy for mesothelioma, and discuss the advantages of gene therapy in the context of stimulating host immune systems. Accumulating clinical data suggest that an intrapleural administration of viral vectors has distinct aspects which are not observed in other administration routes.

Arsenic, asbestos and radon: emerging players in lung tumorigenesis

The cause of lung cancer is generally attributed to tobacco smoking. However lung cancer in never smokers accounts for 10 to 25% of all lung cancer cases. Arsenic, asbestos and radon are three prominent non-tobacco carcinogens strongly associated with lung cancer. Exposure to these agents can lead to genetic and epigenetic alterations in tumor genomes, impacting genes and pathways involved in lung cancer development. Moreover, these agents not only exhibit unique mechanisms in causing genomic alterations, but also exert deleterious effects through common mechanisms, such as oxidative stress, commonly associated with carcinogenesis. This article provides a comprehensive review of arsenic, asbestos, and radon induced molecular mechanisms responsible for the generation of genetic and epigenetic alterations in lung cancer. A better understanding of the mode of action of these carcinogens will facilitate the prevention and management of lung cancer related to such environmental hazards.

Elimination of asbestos use and asbestos-related diseases: an unfinished story

Asbestos is a proven human carcinogen. Asbestos-related diseases (ARDs) typically comprise lung cancer, malignant mesothelioma, asbestosis, pleural plaques, thickening and effusion. International organizations, notably the World Health Organization and the International Labour Organization, have repeatedly declared the need to eliminate ARDs, and have called on countries to stop using asbestos. However, the relevant national-level indicators (e.g., incidence/mortality rates and per capita asbestos use, as well as their interrelationships) indicate that ARDs are increasing and asbestos use is continuing in the world. Lessons learned by industrialized countries in terms of policy and science have led to a growing number of countries adopting bans. In contrast, industrializing countries are faced with a myriad of forces prompting them to continue using asbestos. Full-scale international cooperation will thus be needed, with industrialized countries sharing their experiences and technologies to enable industrializing countries to make smooth transitions to banned states and achieve the goal of eliminating ARDs.

A decade of malignant mesothelioma surveillance in Korea

BACKGROUND

The objectives of this study were to examine trends in mesothelioma incidence over a decade and to identify histories of asbestos exposure among cases in Korea.

METHODS

In 2001, The Korea Occupational Safety and Health Agency organized a nationwide cardiopulmonary pathology group and established a malignant mesothelioma surveillance system covering all general hospitals in Korea. Mesothelioma cases were reported to this surveillance system with information about age, gender, location, occupational history, asbestos exposure environment, date of diagnosis, diagnostic method, histopathologic subtype, occurrence site, and other clinical information. Additionally, an epidemiological survey was conducted using a structured verbal questionnaire to allow further evaluation of asbestos exposures.

RESULTS

A total of 399 cases of malignant mesothelioma were reported in the last decade, translating to approximately 40 annual cases, and an annual average incidence rate of 0.83 cases per million. Of the 152 patients interviewed by occupational physicians, 56 had occupational asbestos exposure histories (36.8%). Their occupations and industries included construction (19.7%), automobile repair (5.9%), asbestos textile, shipbuilding and repair, refinery work, boiler making, and asbestos cement work. Another 31 patients had environmental asbestos exposure histories.

CONCLUSIONS

Surveillance data indicate that malignant mesothelioma incidence in Korea is, thus far, lower than that of other developed countries, and that construction and environmental asbestos exposure were the main identifiable causes of malignant mesothelioma.

Genome-wide gene-environment interaction analysis for asbestos exposure in lung cancer susceptibility

Asbestos exposure is a known risk factor for lung cancer. Although recent genome-wide association studies (GWASs) have identified some novel loci for lung cancer risk, few addressed genome-wide gene-environment interactions. To determine gene-asbestos interactions in lung cancer risk, we conducted genome-wide gene-environment interaction analyses at levels of single nucleotide polymorphisms (SNPs), genes and pathways, using our published Texas lung cancer GWAS dataset. This dataset included 317 498 SNPs from 1154 lung cancer cases and 1137 cancer-free controls. The initial SNP-level P-values for interactions between genetic variants and self-reported asbestos exposure were estimated by unconditional logistic regression models with adjustment for age, sex, smoking status and pack-years. The P-value for the most significant SNP rs13383928 was 2.17×10(-6), which did not reach the genome-wide statistical significance. Using a versatile gene-based test approach, we found that the top significant gene was C7orf54, located on 7q32.1 (P = 8.90×10(-5)). Interestingly, most of the other significant genes were located on 11q13. When we used an improved gene-set-enrichment analysis approach, we found that the Fas signaling pathway and the antigen processing and presentation pathway were most significant (nominal P < 0.001; false discovery rate < 0.05) among 250 pathways containing 17 572 genes. We believe that our analysis is a pilot study that first describes the gene-asbestos interaction in lung cancer risk at levels of SNPs, genes and pathways. Our findings suggest that immune function regulation-related pathways may be mechanistically involved in asbestos-associated lung cancer risk.

The ticking time-bomb of asbestos: its insidious role in the development of malignant mesothelioma

The relationship between asbestos exposure and malignant mesothelioma (MM) has been well established. Despite bans on asbestos use in an increasing number of nations, the prolonged latency from exposure to diagnosis, and the ongoing presence and use of these dangerous fibres, have led to the increasing prevalence of this deadly disease worldwide. Whilst occupational contact has been implicated in the bulk of diagnosed cases over the past 50 years, a significant proportion of disease has been linked to para-occupational, domestic and environmental exposure. In this review, we will provide an update on the impact of historical and ongoing asbestos contact in both occupational and non-occupational settings. Furthermore, we will address the unresolved controversies surrounding the use of chrysotile asbestos, the effect of gender and genetics on development of this disease, childhood mesothelioma and co-aetiological factors including SV40 exposure.

Applying quality criteria to exposure in asbestos epidemiology increases the estimated risk

Mesothelioma deaths due to environmental exposure to asbestos in The Netherlands led to parliamentary concern that exposure guidelines were not strict enough. The Health Council of the Netherlands was asked for advice. Its report has recently been published. The question of quality of the exposure estimates was studied more systematically than in previous asbestos meta-analyses. Five criteria of quality of exposure information were applied, and cohort studies that failed to meet these were excluded. For lung cancer, this decreased the number of cohorts included from 19 to 3 and increased the risk estimate 3- to 6-fold, with the requirements for good historical data on exposure and job history having the largest effects. It also suggested that the apparent differences in lung cancer potency between amphiboles and chrysotile may be produced by lower quality studies. A similar pattern was seen for mesothelioma. As a result, the Health Council has proposed that the occupational exposure limit be reduced from 10 000 fibres m(-3) (all types) to 250 f m(-3) (amphiboles), 1300 f m(-3) (mixed fibres), and 2000 f m(-3) (chrysotile). The process illustrates the importance of evaluating quality of exposure in epidemiology since poor quality of exposure data will lead to underestimated risk.

Compensation scheme for complementary and alternative medicine use in asbestos-related diseases in New South Wales, Australia

WHAT IS KNOWN AND OBJECTIVE

Asbestos use has resulted in a high global incidence rate of asbestos-related diseases (ARDs). These diseases require high costs of compensation and medical expense, although definite cures have yet to be found. Complementary and alternative medicine (CAM) has been used as a means to attenuate symptoms of ARDs. Our objective is to describe the compensation scheme for CAM use for a population with ARDs in New South Wales (NSW), Australia.

COMMENT

Expenses of CAM have conditionally been compensated by the workers compensation dust-diseases board (DDB) to a population with ARDs. The DDB approves patients` claim for the use of CAM if it is justifiable and related to compensable ARDs. To obtain the DDB`s approval for the CAM cost, a written recommendation letter by the treating medical doctors is required that justifies the use of CAM and that this option does not pose any adverse effects on the compensated patients.

WHAT IS NEW AND CONCLUSION

The use of CAM in a subject with ARDs does not have significant benefits of overall survival but does somewhat improve quality of life. However, awareness of the provisions of the compensation scheme for CAM use in a population with ARDs should be carefully informed and also emphasized any side effects on progress of ARDs.

The global reorganization and revitalization of the asbestos industry, 1970-2007

The intent of this essay is to highlight the global reorganization of the asbestos industry over the period 1970-2007. Descriptive analysis illustrates that asbestos consumption in the industrialized countries declined precipitously over this period, in juxtaposition to a notable increase in consumption in the developing countries. In 2007, asbestos consumption in the developing countries was more than two million metric tons but negligible elsewhere in the world economy. The author argues that as asbestos increasingly became the focus of government oversight in the industrialized countries, continued capital accumulation efforts necessitated displacement of risk to the developing countries. The global revitalization of asbestos production and consumption over the period 1970-2007 presents numerous challenges in terms of occupational and environmental health hazards in the developing countries. It has the potential, moreover, to prefigure a significant expansion of asbestos-related disease into the 21st century, absent a global ban on asbestos use.

Mesothelioma and analysis of tissue fiber content

The strong relationship between mesothelioma and asbestos exposure is well established. The analysis of lung asbestos burden by light and electron microscopy assisted to understand the increased incidence of mesothelioma in asbestos mining and consuming nations.The data on the occupational exposure to asbestos are important information for the purpose of compensation of occupational disease No. 4105 (asbestos-associated mesothelioma) in Germany.However, in many cases the patients have forgotten conditions of asbestos exposure or had no knowledge about the used materials with components of asbestos. Mineral fiber analysis can provide valuable information for the research of asbestos-associated diseases and for the assessment of exposure. Because of the variability of asbestos exposure and long latency periods, the analysis of asbestos lung content is a relevant method for identification of asbestos-associated diseases. Also, sources of secondary exposure, so called "bystander exposition" or environmental exposure can be examined by mineral fiber analysis.Household contacts to asbestos are known for ten patients (1987-2009) in the German mesothelioma register; these patients lived together with family members working in the asbestos manufacturing industry.Analysis of lung tissue for asbestos burden offers information on the past exposure. The predominant fiber-type identified by electron microscopy in patients with mesothelioma is amphibole asbestos (crocidolite or amosite). Latency times (mean 42.5 years) and mean age at the time of diagnose in patients with mesothelioma are increasing (65.5 years). The decrease of median asbestos burden of the lung in mesothelioma patients results in disease manifestation at a higher age.Lung dust analyses are a relevant method for the determination of causation in mesothelioma. Analysis of asbestos burden of the lung and of fiber type provides insights into the pathogenesis of malignant mesothelioma. The most important causal factor for the development of mesothelioma is still asbestos exposure.

Global mesothelioma deaths reported to the World Health Organization between 1994 and 2008

OBJECTIVE

To carry out a descriptive analysis of mesothelioma deaths reported worldwide between 1994 and 2008.

METHODS

We extracted data on mesothelioma deaths reported to the World Health Organization mortality database since 1994, when the disease was first recorded. We also sought information from other English-language sources. Crude and age-adjusted mortality rates were calculated and mortality trends were assessed from the annual percentage change in the age-adjusted mortality rate.

FINDINGS

In total, 92,253 mesothelioma deaths were reported by 83 countries. Crude and age-adjusted mortality rates were 6.2 and 4.9 per million population, respectively. The age-adjusted mortality rate increased by 5.37% per year and consequently more than doubled during the study period. The mean age at death was 70 years and the male-to-female ratio was 3.6:1. The disease distribution by anatomical site was: pleura, 41.3%; peritoneum, 4.5%; pericardium, 0.3%; and unspecified sites, 43.1%. The geographical distribution of deaths was skewed towards high-income countries: the United States of America reported the highest number, while over 50% of all deaths occurred in Europe. In contrast, less than 12% occurred in middle- and low-income countries. The overall trend in the age-adjusted mortality rate was increasing in Europe and Japan but decreasing in the United States.

CONCLUSION

The number of mesothelioma deaths reported and the number of countries reporting deaths increased during the study period, probably due to better disease recognition and an increase in incidence. The different time trends observed between countries may be an early indication that the disease burden is slowly shifting towards those that have used asbestos more recently.

Genes associated with prognosis after surgery for malignant pleural mesothelioma promote tumor cell survival in vitro

Background

Mesothelioma is an aggressive neoplasm with few effective treatments, one being cytoreductive surgery. We previously described a test, based on differential expression levels of four genes, to predict clinical outcome in prospectively consented mesothelioma patients after surgery. In this study, we determined whether any of these four genes could be linked to a cancer relevant phenotype.

Methods

We conducted a high-throughput RNA inhibition screen to knockdown gene expression levels of the four genes comprising the test (ARHGDIA, COBLL1, PKM2, TM4SF1) in both a human lung-derived normal and a tumor cell line using three different small inhibitory RNA molecules per gene. Successful knockdown was confirmed using quantitative RT-PCR. Detection of statistically significant changes in apoptosis and mitosis was performed using immunological assays and quantified using video-assisted microscopy at a single time-point. Changes in nuclear shape, size, and numbers were used to provide additional support of initial findings. Each experiment was conducted in triplicate. Specificity was assured by requiring that at least 2 different siRNAs produced the observed change in each cell line/time-point/gene/assay combination.

Results

Knockdown of ARHGDIA, COBLL1, and TM4SF1 resulted in 2- to 4-fold increased levels of apoptosis in normal cells (ARHGDIA only) and tumor cells (all three genes). No statistically significant changes were observed in apoptosis after knockdown of PKM2 or for mitosis after knockdown of any gene.

Conclusions

We provide evidence that ARHGDIA, COBLL1, and TM4SF1 are negative regulators of apoptosis in cultured tumor cells. These genes, and their related intracellular signaling pathways, may represent potential therapeutic targets in mesothelioma.

Global magnitude of reported and unreported mesothelioma

BACKGROUND

Little is known about the global magnitude of mesothelioma. In particular, many developing countries, including some with extensive historical use of asbestos, do not report mesothelioma.

OBJECTIVES

We estimated the global magnitude of mesothelioma accounting for reported and unreported cases.

METHODS

For all countries with available data on mesothelioma frequency and asbestos use (n=56), we calculated the 15-year cumulative number of mesotheliomas during 1994-2008 from data available for fewer years and assessed its relationship with levels of cumulative asbestos use during 1920-1970. We used this relationship to predict the number of unreported mesotheliomas in countries for which no information on mesothelioma is available but which have recorded asbestos use (n=33).

RESULTS

Within the group of 56 countries with data on mesothelioma occurrence and asbestos use, the 15-year cumulative number of mesothelioma was approximately 174,300. There was a statistically significant positive linear relation between the log-transformed national cumulative mesothelioma numbers and the log-transformed cumulative asbestos use (adjusted R(2)=0.83, p<0.0001). Extrapolated to the group of 33 countries without reported mesothelioma, a total of approximately 38,900 (95% confidence interval, 36,700-41,100) mesothelioma cases were estimated to have occurred in the 15-year period (1994-2008).

CONCLUSIONS

We estimate conservatively that, globally, one mesothelioma case has been overlooked for every four to five reported cases. Because our estimation is based on asbestos use until 1970, the many countries that increased asbestos use since then should anticipate a higher disease burden in the immediate decades ahead.

[Guidelines of the European Respiratory Society and the European Society of Thoracic Surgeons for the management of malignant pleural mesothelioma]

恶性胸膜间皮瘤（malignant pleural mesothelioma, MPM）是一种罕见肿瘤，但发病率正逐渐上升，且预后较差。2008年，欧洲呼吸学会（European Respiratory Society, ERS）和欧洲胸外科医师学会（European Society of Thoracic Surgeons, ESTS）特别工作组召集各方专家计划制定MPM诊治经验及更新指南。

为了使MPM得到及时准确的诊断，专家推荐对患者实施胸腔镜检查，有手术禁忌和胸腔粘连的病例除外。约10%的病例采用标准染色方法无法获得满意的结果。因此我们推荐在胸膜活检的基础上，采用特异性免疫组化标志物。由于目前缺乏一个统一的、切实有效的分期系统，我们推荐应用最新的TNM分期，并且提出三个阶段的治疗前评估。在MPM的治疗中，患者的体力状态评分和组织亚型是目前唯一的、具有重要临床价值的预后因素。在临床试验中，应对其它潜在因素进行初步探讨并予以报道。MPM对化疗高度耐受，仅有少数患者可接受根治性手术。本文对新的治疗方法和策略进行了综述。

目前由于最佳综合治疗的资料有限，适合采用多种方案联合治疗策略的患者应被纳入专业机构的前瞻性试验中。

Towards elimination of asbestos-related diseases: a theoretical basis for international cooperation

We develop a theoretical framework for international cooperation that can be used for the elimination of asbestos-related diseases (ARDs). The framework is based on the similarities in the temporal patterns of asbestos use and occurrence of ARDs in diverse countries. The status of each nation can be characterized by observing asbestos use and ARD frequency therein using a time window. Countries that supply technology for prevention of ARDs can be classified as donors and countries that receive these technologies as recipients. We suggest identification of three levels of core preventative technologies. Development of a common platform to gather and manage core preventative technologies will combine the strengths of donor countries and the needs of recipient countries.

Asbestos is still with us: repeat call for a universal ban

All forms of asbestos are proven human carcinogens. All forms of asbestos cause malignant mesothelioma, lung, laryngeal, and ovarian cancers, and may cause gastrointestinal and other cancers. No exposure to asbestos is without risk, and there is no safe threshold of exposure to asbestos. Asbestos cancer victims die painful lingering deaths. These deaths are almost entirely preventable. When evidence of the carcinogenicity of asbestos became incontrovertible, concerned parties, including the Collegium Ramazzini, called for a universal ban on the mining, manufacture and use of asbestos in all countries around the world [1]. Asbestos is now banned in 52 countries [2], and safer products have replaced many materials that once were made with asbestos. Nonetheless, a large number of countries still use, import, and export asbestos and asbestos-containing products. And still today in many countries that have banned other forms of asbestos, the so-called "controlled use" of chrysotile asbestos continues to be permitted, an exemption that has no basis in medical science but rather reflects the political and economic influence of the asbestos mining and manufacturing industry. To protect the health of all people in the world-industrial workers, construction workers, women and children, now and in future generations-the Collegium Ramazzini calls again today on all countries of the world, as we have repeatedly in the past to join in the international endeavor to ban all forms of asbestos. An international ban on asbestos is urgently needed. New Solutions is one of ten international journals that have agreed to publish the Repeat Call in order to bring the message to a wide readership.

The case for a global ban on asbestos

BACKGROUND

All forms of asbestos are now banned in 52 countries. Safer products have replaced many materials that once were made with it. Nonetheless, many countries still use, import, and export asbestos and asbestos-containing products, and in those that have banned other forms of asbestos, the so-called "controlled use" of chrysotile asbestos is often exempted from the ban. In fact, chrysotile has accounted for > 95% of all the asbestos used globally.

OBJECTIVE

We examined and evaluated the literature used to support the exemption of chrysotile asbestos from the ban and how its exemption reflects the political and economic influence of the asbestos mining and manufacturing industry.

DISCUSSION

All forms of asbestos, including chrysotile, are proven human carcinogens. All forms cause malignant mesothelioma and lung and laryngeal cancers, and may cause ovarian, gastrointestinal, and other cancers. No exposure to asbestos is without risk. Illnesses and deaths from asbestos exposure are entirely preventable.

CONCLUSIONS

All countries of the world have an obligation to their citizens to join in the international endeavor to ban the mining, manufacture, and use of all forms of asbestos. An international ban is urgently needed. There is no medical or scientific basis to exempt chrysotile from the worldwide ban of asbestos.

Asbestos is still with us: repeat call for a universal ban

All forms of asbestos are proven human carcinogens. All forms of asbestos cause malignant mesothelioma, lung, laryngeal, and ovarian cancers, and may cause gastrointestinal and other cancers. No exposure to asbestos is without risk. Asbestos cancer victims die painful lingering deaths. These deaths are almost entirely preventable. When evidence of the carcinogenicity of asbestos became incontrovertible, concerned parties, including the Collegium Ramazzini, called for a universal ban on the mining, manufacture, and use of asbestos in all countries around the world (J Occup Environ Med. 1999;41:830-832). Asbestos is now banned in 52 countries, and safer products have replaced many materials that once were made with asbestos. Nonetheless, a large number of countries still use, import, and export asbestos and asbestos-containing products. And in many countries that have banned other forms of asbestos, the so-called "controlled use" of chrysotile asbestos is exempted from the ban, an exemption that has no basis in medical science but rather reflects the political and economic influence of the asbestos mining and manufacturing industry. All countries of the world have an obligation to their citizens to join in the international endeavor to ban all forms of asbestos. An international ban on asbestos is urgently needed.

Retrospective exposure assessment to airborne asbestos among power industry workers

Background

A method of individually assessing former exposure to asbestos fibres is a precondition of risk-differentiated health surveillance. The main aims of our study were to assess former levels of airborne asbestos exposure in the power industry in Germany and to propose a basic strategy for health surveillance and the early detection of asbestos related diseases.

Methods

Between March 2002 and the end of 2006, we conducted a retrospective questionnaire based survey of occupational tasks and exposures with airborne asbestos fibres in a cohort of 8632 formerly asbestos exposed power industry workers. The data on exposure and occupation were entered into a specially designed computer programme, based on ambient monitoring of airborne asbestos fibre concentrations. The cumulative asbestos exposure was expressed as the product of the eight-hour time weighted average and the total duration of exposure in fibre years (fibres/cubic centimetre-years).

Results

Data of 7775 (90% of the total) participants working in installations for power generation, power distribution or gas supply could be evaluated. The power generation group (n = 5284) had a mean age of 56 years, were exposed for 20 years and had an average cumulative asbestos exposure of 42 fibre years. The occupational group of "metalworkers" (n = 1600) had the highest mean value of 79 fibre years. The corresponding results for the power distribution group (n = 2491) were a mean age of 45 years, a mean exposure duration of 12 years and an average cumulative asbestos exposure of only 2.5 fibre years. The gas supply workers (n = 512) had a mean age of 54 years and a mean duration of exposure of 15 years.

Conclusions

While the surveyed cohort as a whole was heavily exposed to asbestos dust, the power distribution group had a mean cumulative exposure of only 6% of that found in the power generation group. Based on the presented data, risk-differentiated disease surveillance focusing on metalworkers and electricians from the power generating industry seems justified. That combined with a sensitive examination technique would allow detecting asbestos related diseases early and efficiently.

Are current or future mesothelioma epidemics in Hong Kong the tragic legacy of uncontrolled use of asbestos in the past?

Inhaled asbestos fibers may contribute to three-fourths of malignant mesotheliomas diagnosed in men and almost 40% of cases diagnosed in women. Bans on the manufacture and sale of amphibole asbestos fibers are expected to reduce the incidence of mesothelioma, but the long latency period from initial exposure to clinical disease means that people exposed before bans were enacted will continue to develop asbestos-related mesotheliomas as they age. Tse et al. (p. 382) used historical data on asbestos consumption and mesothelioma diagnoses to predict future mesothelioma trends in Hong Kong. Asbestos use peaked during a construction boom in the early 1960s and subsequently declined by > 90% following a ban on the sale and import of crocidolite and amosite asbestos in 1996, whereas mesothelioma diagnoses in men increased from a single case in 1972–1976 to 63 cases in 2002–2006 (corresponding to crude incidence rates of 0.09 and 3.86 cases/million men, respectively). Assuming an average latency of 42 years, the authors predict that incidence rates will peak in 2009 and that diagnoses will peak in 2014. However, they caution that ongoing use of chrysotile asbestos and the release of asbestos fibers from older buildings during demolition or renovation may slow the projected decline. [corrected]

National use of asbestos in relation to economic development

BACKGROUND

National disparities in asbestos use will likely lead to an unequal burden of asbestos diseases.

OBJECTIVES

As economic status may be linked to asbestos use, we assessed, globally, the relationship between indicators of national economic development and asbestos use.

METHODS

For the 135 countries that have ever used asbestos, per capita asbestos use (kilograms per capita per year) was compared with per capita gross domestic product (GDP) in 1990 Geary-Khamis dollars (GKD) for the period 1920-2003. Countries were grouped into three income levels (high, middle, and low) that were adapted from the 2003 World Bank categories.

RESULTS

The historical pattern of asbestos use followed the environmental Kuznets curve in which use by high-income countries peaked when incomes attained 10,000-15,000 GKD and essentially ceased at income levels over 20,000 GKD. Currently, middle- and low-income countries are increasing their use of asbestos, closely following the paths once traced by higher income countries.

CONCLUSIONS

Developing countries have the opportunity to eliminate asbestos use sooner than high-income countries and thus reduce the future burden of asbestos diseases.

Occupational safety and health’s role in sustainable, responsible nanotechnology: gaps and needs

The newly fledged nanotechnologies offer opportunities for social development, but uncertainties prevail about their impact on human and environmental health. There is still a huge gap between technological progress and research into the health and safety aspects of nanomaterials. This is clear from the quantity of nanoproducts already on the market — more than 600 — and the public and private funds dedicated to the development of nanotechnologies, which are almost a hundred times those available for research into their effects on health and safety. Estimates have it that by 2014, nanotechnologies will be widely used in our society and ten million new jobs will be created. Therefore, it becomes essential to plan an integrated approach to specific risk analysis at work. The following gaps and needs come to light: limited information, difficulties in relating nanotechnologies and production of nanomaterials to specific areas of application, efforts required to assess the hazards posed by nanomaterials in realistic exposure conditions, ethical issues about nanotechnology in the workplace likely to arise from today’s knowledge about the hazards of nanomaterials and the risks they may pose to workers. An integrated approach to research, cooperation, and communication strategies is essential if we are to direct our efforts toward responsible and sustainable growth of nanotechnologies.

Malignant pleural mesothelioma in Italy

This study reviews a series of 811 malignant pleural mesothelioma cases, diagnosed at hospitals in Trieste and Monfalcone districts of north eastern Italy, a narrow coastal strip with a population of about three lakh, in the period 1968-2008. The diagnosis was based on histological examination in 801 cases, and cytological findings in 10. Necropsy was performed in 610 cases. Occupational histories were obtained directly from the patients or their relatives through personal or telephone interviews. Routine lung sections were examined for asbestos bodies in 500 cases. In 143 cases asbestos bodies were isolated and counted by chemical digestion of the lung tissue using the Smith-Naylor method. The series included 717 men and 94 women aged between 32 and 93 years (mean 69.2 years). Detailed occupational data was obtained for 732 cases.The majority of patients had marine jobs - shipbuilding (449 cases), maritime trades (56 cases), and port activities (39 cases). The nature of work of other patients included a variety of occupations, with non-shipbuilding industries being the most common. Thirty-four women cleaned the work clothes of family members occupationally exposed and hence had a history of asbestos exposure at home. Most of the patients had their first exposure to asbestos before 1960. The latency period ranged between 13 and 73 years (mean 48.2). Latency period among insulators and dock workers were shorter than other categories. Asbestos bodies were detected on routine lung sections in 343 cases (68.6%). Lung asbestos body burdens after isolation ranged between two to 10 millions bodies per gram of dried tissue. Despite some limitations in the use of asbestos in this area since the 1970s, the incidence of tumor remained high during the last years.

Fiber types, asbestos potency, and environmental causation: a peer review of published work and legal and regulatory scientific testimony

Scientific evidence and analysis offered in litigation and public policy testimony have an important role in occupational and environmental health, but are not subject to peer review. Critique and commentary, attempts at reproduction of results, and review of data offered in such testimony is essential. Peer review of such testimony should become part of the domain of medical and scientific journals. This paper is an effort to peer review the use of certain scientific methods in tort litigation and in testimony before regulatory agencies. In this issue of IJOEH, Azuma et al. show that background asbestos exposures can be considered to have caused mesothelioma. In contrast, epidemiologic studies and testimony by Teta et al. and Price and Ware, and pathologic studies and testimony by Roggli and others, claim that background exposures are benign. These are fatally flawed because of methodological and analytic errors.

Impact of malignant mesothelioma in Taiwan: a 27-year review of population-based cancer registry data

PURPOSE

To describe the epidemiologic characteristics of malignant mesothelioma (MM) in Taiwan; to evaluate the impact of the condition.

METHODS

The Taiwan Cancer Registry Database was used to retrieve the cases of MM registered from 1979 to 2005. Only cases of histopathologically verified MM were included. For evaluating the impact of MM, the cancer sites of the pleura and peritoneum (ICD-O codes 163 and 158, respectively) were used for statistical analysis and estimation of the expected years of life lost (EYLL). Their survival was calculated by Kaplan-Meier analysis and extrapolated to obtain the EYLL using the Monte Carlo simulation by borrowing information from gender- and age-matched populations in Taiwan.

RESULTS

A total of 423 cases of MM were included; MM of the pleura and peritoneum accounted for 91% of all cases (387/423). The median survival of pleural and peritoneal MM was 7.6 and 13.5 months for males and females, respectively. The incidence of MM increased during the observation period. A total of 232 males and 155 females diagnosed with MM were used for estimation of EYLL: 14.8 [95% Confidence Interval: 13.1-16.6] life years for males and 13.7 [11.2-16.2] life years for females.

CONCLUSION

The increasing incidence and significant EYLL for MM were observed for both males and females during 1979-2005 in Taiwan, although under-diagnosis and under-estimation were likely.

Serum growth factors in asbestosis patients

Various growth factors, including platelet-derived growth factor (PDGF) and transforming growth factor (TGF)-beta, have been implicated in the pathogenesis of asbestos-induced disease. PDGF and TGF-beta levels were determined by enzyme-linked immunosorbent assays in the banked serum samples of a cohort of workers with asbestosis, and the relationships of the growth factor levels to the subsequent development of cancer and to the radiographic severity and progression of asbestosis in the cohort were examined. Serum levels of PDGF and TGF-beta were found to be unrelated to the development of cancer, and serum levels of PDGF were found to be unrelated to the severity and progression of asbestosis. However, serum levels of TGF-beta were found to be statistically significantly related to disease severity (p = 0.01), increasing approximately 2.4-fold from ILO radiographic category 0 to category 3, and they were marginally related to disease progression (p = 0.07), in multivariate analysis controlling for other contributory factors including cumulative asbestos exposure. This suggests that serum TGF-beta may be a useful biomarker for asbestos-induced fibrotic disease.

Asbestos-induced lung diseases: an update

Asbestos causes asbestosis (pulmonary fibrosis caused by asbestos inhalation) and malignancies (bronchogenic carcinoma and mesothelioma) by mechanisms that are not fully elucidated. Despite a dramatic reduction in asbestos use worldwide, asbestos-induced lung diseases remain a substantial health concern primarily because of the vast amounts of fibers that have been mined, processed, and used during the 20th century combined with the long latency period of up to 40 years between exposure and disease presentation. This review summarizes the important new epidemiologic and pathogenic information that has emerged over the past several years. Whereas the development of asbestosis is directly associated with the magnitude and duration of asbestos exposure, the development of a malignant clone of cells can occur in the setting of low-level asbestos exposure. Emphasis is placed on the recent epidemiologic investigations that explore the malignancy risk that occurs from nonoccupational, environmental asbestos exposure. Accumulating studies are shedding light on novel mechanistic pathways by which asbestos damages the lung. Attention is focused on the importance of alveolar epithelial cell (AEC) injury and repair, the role of iron-derived reactive oxygen species (ROS), and apoptosis by the p53- and mitochondria-regulated death pathways. Furthermore, recent evidence underscores crucial roles for specific cellular signaling pathways that regulate the production of cytokines and growth factors. An evolving role for epithelial-mesenchymal transition (EMT) is also reviewed. The translational significance of these studies is evident in providing the molecular basis for developing novel therapeutic strategies for asbestos-related lung diseases and, importantly, other pulmonary diseases, such as interstitial pulmonary fibrosis and lung cancer.

Asbestos disease in Australia: looking forward and looking back

This article provides an overview and analysis of recent developments in policy and practice in relation to asbestos disease in Australia. It complements three other concurrent publications in this issue representing important contributions of people and organizations toward addressing the health and social impacts of Australia's asbestos disease epidemic. The campaign to "Make James Hardie Pay" as well as the efforts of workers and advocates are profiled in this article as well as in this issue's Documents and Voices sections. Discussion of recent developments in asbestos-related disease research and mesothelioma surveillance is followed by articulation of the comprehensive public and social health response that is needed to fully engage and address the asbestos disease legacy and to apply lessons learned to help revive the currently waning societal commitment to occupational health and safety in Australia and elsewhere.

Treatment of malignant pleural mesothelioma with carboplatin, liposomized doxorubicin, and gemcitabine: a phase II study

BACKGROUND

Malignant pleural mesothelioma has a poor prognosis and there is limited effect of treatment. The Nordic Mesothelioma groups decided in the year 2000 to investigate a combination of liposomized doxorubicin, carboplatin, and gemcitabine for this disease in a phase II study.

METHODS

From January 2001, to December 2003, 173 evaluable patients with biopsy-verified malignant mesothelioma were included. Two patients were lost to follow-up, but all the others were followed for at least 4 years or until death.

RESULTS

Toxicity was fairly low. There were 56 responses (32.4%), of which 2 were complete; the median time to progression was 8.6 months, and the median overall survival was 13 months. Some patients had their responses 4 to 6 months after last treatment. For 116 patients with epitheloid subtype, median survival was 17 months. A subgroup of these patients with good performance status, early stage, and age 70 years or less, showed a median survival of 22 months.

CONCLUSION

The treatment yields good results with a high number of responses and long survival, and a low toxicity. The long survival of the epitheloid subgroup with good prognostic factors is as good as or even better than some studies on "radical" surgery or multimodal treatment, underlining the need of randomized studies to evaluate such treatment options.