Belgium: historical champion in asbestos consumption

Disease mapping of zero-excessive mesothelioma data in Flanders

PURPOSE

To investigate the distribution of mesothelioma in Flanders using Bayesian disease mapping models that account for both an excess of zeros and overdispersion.

METHODS

The numbers of newly diagnosed mesothelioma cases within all Flemish municipalities between 1999 and 2008 were obtained from the Belgian Cancer Registry. To deal with overdispersion, zero inflation, and geographical association, the hurdle combined model was proposed, which has three components: a Bernoulli zero-inflation mixture component to account for excess zeros, a gamma random effect to adjust for overdispersion, and a normal conditional autoregressive random effect to attribute spatial association. This model was compared with other existing methods in literature.

RESULTS

The results indicate that hurdle models with a random effects term accounting for extra variance in the Bernoulli zero-inflation component fit the data better than hurdle models that do not take overdispersion in the occurrence of zeros into account. Furthermore, traditional models that do not take into account excessive zeros but contain at least one random effects term that models extra variance in the counts have better fits compared to their hurdle counterparts. In other words, the extra variability, due to an excess of zeros, can be accommodated by spatially structured and/or unstructured random effects in a Poisson model such that the hurdle mixture model is not necessary.

CONCLUSIONS

Models taking into account zero inflation do not always provide better fits to data with excessive zeros than less complex models. In this study, a simple conditional autoregressive model identified a cluster in mesothelioma cases near a former asbestos processing plant (Kapelle-op-den-Bos). This observation is likely linked with historical local asbestos exposures. Future research will clarify this.

Asbestos bodies in bronchoalveolar lavage in the 21st century: a time-trend analysis in a clinical population

OBJECTIVES

Asbestos bodies (AB) in bronchoalveolar lavage (BAL) can be detected by light microscopy and their concentration is indicative of past cumulative asbestos exposure. We assessed clinical and exposure characteristics, as well as possible time trends, among patients in whom AB had been quantified in BAL.

METHODS

BAL samples obtained from 578 participants between January 1997 and December 2014 were available for analysis. The processing of samples and the microscopic analysis were performed by a single expert and 76% of samples came from a single tertiary care hospital, allowing clinical and exposure data to be extracted from patient files.

RESULTS

The study population (95% males) had a mean age of 62.5 (±12.4) years. AB were detected in 55.2% of the samples, giving a median concentration of 0.5 AB/mL (95th centile: 23.6 AB/mL; highest value: 164.5 AB/mL). The AB concentration exceeded 1 AB/mL in 39.4% and 5 AB/mL in 17.8%. A significant decrease from a geometric mean of 0.93 AB/mL in 1997 to 0.2 AB/mL in 2014 was apparent. High AB concentrations generally corresponded with occupations with (presumed) high asbestos exposure. AB concentrations were higher among patients with asbestosis and pleural plaques, when compared with other disease groups. Nevertheless, a substantial proportion of participants with likely exposure to asbestos did not exhibit high AB counts.

CONCLUSIONS

This retrospective study of a large clinical population supports the value of counting AB in BAL as a complementary approach to assess past exposure to asbestos.

Enduring health effects of asbestos use in Belgian industries: a record-linked cohort study of cause-specific mortality (2001-2009)

OBJECTIVE

To investigate cause-specific mortality among asbestos workers and potentially exposed workers in Belgium and evaluate potential excess in mortality due to established and suspected asbestos-related diseases.

DESIGN

This cohort study is based on an individual record linkage between the 1991 Belgian census and cause-specific mortality information for Flanders and Brussels (2001-2009).

SETTING

Belgium (Flanders and Brussels region).

PARTICIPANTS

The study population consists of 1,397,699 male workers (18-65,years) with 72,074 deaths between 1 October 2001 and 31 December 2009. Using a classification of high-risk industries, mortality patterns between 2056 asbestos workers, 385,046 potentially exposed workers and the working population have been compared.

OUTCOME MEASURES

Standardised mortality ratios (SMRs) and 95% CIs are calculated for manual and non-manual workers.

RESULTS

Our findings show clear excess in asbestos-related mortality in the asbestos industry with SMRs for mesothelioma of 4071 (CI 2327 to 6611) among manual workers and of 4489 (CI 1458 to 10,476) among non-manual workers. Excess risks in asbestos-related mortality are also found in the chemical industry, the construction industry, the electrical generation and distribution industry, the basic metals manufacturing industry, the metal products manufacturing industry, the railroad industry, and the shipping industry. Oral cancer mortality is significantly higher for asbestos workers (SMR 383; CI 124 to 894), railroad workers (SMR 192; CI 112 to 308), shipping workers (SMR 172; CI 102 to 271) and construction workers (SMR 125; CI 100 to 153), indicating a possible association with occupational asbestos exposure. Workers in all four industries have elevated mortality rates for cancer of the mouth. Only construction workers experience significantly higher pharyngeal cancer mortality (SMR 151; CI 104 to 212).

CONCLUSIONS

The study identifies vulnerable groups of Belgian asbestos workers, demonstrating the current-day health repercussions of historical asbestos use. Results support the hypothesis of a possible association between the development of oral cancer and occupational asbestos exposure.

Strengths, weaknesses, and opportunities of diagnostic breathomics in pleural mesothelioma-a hypothesis

Past and present asbestos use will reflect in increasing numbers of mesothelioma cases in the next decades, diagnosed at a late stage and with a dismal prognosis. This stresses the need for early detection tools, which could improve patients' survival. Recently, breath analysis as a noninvasive and fast diagnostic tool has found its way into biomedical research. High-throughput breathomics uses spectrometric, chromatographic, and sensor techniques to diagnose asbestos-related pulmonary diseases based upon volatile organic compounds (VOC) in breath. This article reviews the state-of-the-art available breath analyzing techniques and provides the insight in the current use of VOCs as early diagnostic or prognostic biomarkers of mesothelioma to stimulate further research in this field. Cancer Epidemiol Biomarkers Prev; 23(6); 898-908. ©2014 AACR.

Asbestos in Belgium: an underestimated health risk. The evolution of mesothelioma mortality rates (1969-2009)

Background:

Although Belgium was once a major international manufacturer of asbestos products, asbestos-related diseases in the country have remained scarcely researched.

Objectives:

The aim of this study is to provide a descriptive analysis of Belgian mesothelioma mortality rates in order to improve the understanding of asbestos health hazards from an international perspective.

Methods:

Temporal and geographical analyses were performed on cause-specific mortality data (1969–2009) using quantitative demographic measures. Results were compared to recent findings on global mesothelioma deaths.

Results:

Belgium has one of the highest mesothelioma mortality rates in the world, following the UK, Australia, and Italy. With a progressive increase of male mesothelioma deaths in the mid-1980s, large differences in mortality rates between sexes are apparent. Mesothelioma deaths are primarily concentrated in geographic areas with proximity to former asbestos industries.

Conclusions:

Asbestos mortality in Belgium has been underestimated for decades. Our findings suggest that the location of asbestos industries is correlated with rates of mesothelioma, underlining the need to avert future asbestos exposure by thorough screening of potential contaminated sites and by pursuing a global ban on asbestos.