Sailors and the Risk of Asbestos-Related Cancer

Clinical investigation of former workers exposed to asbestos: the health surveillance experience of an Italian University Hospital

Background

The need for health surveillance of former workers exposed to asbestos was provided by law in Italy after the asbestos ban in 1992.

Objectives

We describe the results of the health surveillance of former workers exposed to asbestos, conducted over 27 years, from 1994 to 2020, at the Operative Unit of Occupational Medicine of the University Hospital of Bari.

Materials and methods

We adopted the health surveillance protocol, which was validated at the national level in 2018.

Results

A total of 1,405 former workers exposed to asbestos were examined. We proceeded with diagnosing pathologies in 339 cases (24% of the cohort subjected to surveillance), with diagnoses of some cases involving multiple pathologies. Specifically, pleural plaques were diagnosed in 49.2% of the 339 cases, asbestosis in 35.9%, malignant pleural mesothelioma (MPM) in 20.3%, mesothelioma of the vaginal tunic of the testis (MTVT) in 9.1%, lung cancer in 5.8%, and laryngeal cancer in 0.8%.

Conclusion

Despite the 1992 asbestos ban, asbestos-related diseases remain a serious public health issue. It is important to establish criteria that ensure the health surveillance of formerly exposed workers minimizes costs, reduces the number of invasive examinations, and optimizes achievable results.

Mesothelioma among seamen: a systematic review and meta-analysis

OBJECTIVES

Navy personnel and seafarers live and work 24 h per day in the shipboard environment and they are exposed to asbestos fibers released into the confined spaces aboard ships. We conducted a systematic review and meta-analysis to quantify the mesothelioma risk of seamen working aboard ships, either commercial or naval vessels, as compared to that of the general population.

METHODS

We carried out a literature search in MEDLINE through PubMed and EMBASE, from inception to 31 December 2021, of all studies on seamen working aboard ships, either commercial or naval vessels, characterized by exposure to asbestos and providing mesothelioma risk estimates. The Newcastle-Ottawa Scale was used to assess the quality of the studies included. The pooled standardized mortality ratio (SMR) was computed across eligible studies. The study protocol was registered on PROSPERO and reporting followed the preferred reporting items for systematic reviews and meta-analyses guidelines.

RESULTS

A total of 10 studies published from 1990 to 2020 were considered eligible and included in the systematic review and meta-analysis. All the included studies were of good quality, with a median score of seven out of nine. Overall, there were 235 mesothelioma cases/deaths in the included studies versus 115.6 expected, with a pooled SMR of 2.11 (95% confidence intervals, 1.70-2.62), in the absence of a significant between-study heterogeneity (I2 = 39%, P = 0.11).

CONCLUSION

A more than double excess risk for mesothelioma among seamen working aboard ships emerged from our meta-analysis.

Asbestos-related cancer in naval personnel: findings from participants in the British nuclear tests 1952-1967

Asbestos-containing materials (ACM) were present in British and Australian naval vessels throughout the twentieth century. The aim of this study was to identify and quantify the incidence of cancer in naval personnel from onboard asbestos exposure. Subjects were four cohorts of subjects who had served in the armed forces of the United Kingdom and Australia in the 1950s and 1960s. All cohorts had previously been studied, three of them in relation to radiation exposures from British nuclear testing. Comparisons of SIRs between services were made to identify cancers attributable to asbestos exposure. Excess mesotheliomas were found in naval personnel in all cohorts. In all but one cohort the lung cancer incidence was highest in navy personnel. Comparison of other smoking-related conditions indicated that the excess in navy personnel was not smoking-related. The relatively high SIRs for mesothelioma and the occurrence of deaths from asbestosis were indicative of high levels of asbestos exposure, with an expectation of cases of asbestos-related lung cancer. The findings are consistent with the occurrence of significant excesses of mesotheliomas. In addition, notwithstanding some inconsistencies in the results between the cohorts, we estimated that approximately 27% of lung cancers in Australian seamen and 12% in British seamen were related to onboard asbestos exposure.

Quantitative assessment of asbestos fibers in some normal and pathological extra-abdominal tissues-a scoping review

BACKGROUND

Asbestos is a mineral present in nature and it has been used for years in numerous settings. Asbestos enters the bloodstream and lymphatic system mainly through breathing.

OBJECTIVES

Studies with asbestos fiber's quantification in human tissues are scarce except for the lung. This article summarizes asbestos studies in some extra-abdominal tissues.

METHODS

A scoping review of articles that quantified asbestos fibers in extra-abdominal tissues (lymph nodes, pharynx, larynx, trachea, heart) by electron microscopy (Scanning-SEM or Transmission-TEM) was performed.

RESULTS

The 10 studies selected comprised 52 cases, out of whom 108 samples were analyzed. Mostly samples were lymph node tissues (102), followed by larynx (3) and myocardium (3). No studies were found that determined the presence of asbestos in the pharynx or trachea. The concentration of asbestos fibers detected in the lymph nodes was from 0.003 million fibers per gram of dry tissue (mfgdt) up to 7400 mfgdt, in the larynx the range was from 0.5 mfgdt up to 3.6 mfgdt, in myocardium no asbestos fibers were detected.

DISCUSSION

The studies included were heterogeneous in terms of case and sample characteristics and analytical techniques. As subjects exposed to asbestos are often positive for fibers in thoracic lymph nodes, we suggest that whenever a human tissue sample is analyzed for asbestos presence, the relevant draining lymph node should be concomitantly studied.

Mesothelioma Risk Among Maritime Workers According to Job Title: Data From the Italian Mesothelioma Register (ReNaM)

The study describes the 466 cases of malignant mesotheliomas (MM) collected by the National Mesothelioma Register (ReNaM) in Italy in the period 1993-2018 relating to subjects with exclusive asbestos exposure in merchant or military navy. The cases among maritime workers represent 1.8% of the total cases with defined exposure registred in the ReNaM, of which 212 cases (45.4%) among merchant maritime workers and 254 cases (54.5%) among navy. The distribution by site of mesothelioma showed 453 (97.2%) MM cases of the pleura, 11 (2.3%) of the peritoneum and 2 (0.4%) of the tunica vaginalis of the testis. With regard to occupational exposure, it was classified as certain in 318 (68.2%) cases, probable in 69 (14.8%) cases and possible in 79 (16.9%) cases. Among the 23 classified jobs, the highest percentages of certain exposures are among naval engineers, motor mechanics, machine captains and sailors. Machine crew accounted for 49.3% of the cases, deck crew for 27.6%. All cases began exposure on board between 1926 and 1988. Seamen were exposed to asbestos while at sea by virtue of living onboard ships and from continual release of asbestos fibers due to the motion of a vessel. Epidemiological surveillance through the ReNaM has allowed us to verify among cases in the maritime, navy and merchant marine sectors, that in the past, subjects were exposed regardless of the ship's department where have provided service therefore all these cases must be considered as occupational diseases.

The role of modifiable risk factors in incident cancer in transport, rescue, and security industries

PURPOSE

Examine the risk for site-specific incident cancer across representative transport, rescue, and security industries.

METHODS

This Danish nationwide register-based study included all 302,789 workers from transport, rescue and security industries in 2001-2015 and 2,230,877 individuals aged 18-64 years from a total sample of the economically active population for comparison. We used Cox models to estimate the hazard ratios (HRs) of incident cancers. We categorized site-specific cancers by using population-attributable fraction (PAF) estimates from the previous literature.

RESULTS

During an average follow-up of 13.4 years, 22,116 incident cancer cases were recorded in these industries. Compared with the reference population, the age-adjusted cancer incidence with a high PAF was higher among men in seafaring (HR 1.28; 95% CI 1.14-1.43), and land transport (HR 1.32; 95% CI: 1.26-1.37), and among women in seafaring (HR 1.26; 95% CI: 1.01-1.57), land transport (HR 1.21; 95% CI: 1.12-1.32), aviation (HR 1.22; 95% CI: 1.05-1.41), and police force (HR 1.21; 95% CI: 1.04-1.40). Overall, tobacco and physical inactivity were the most significant risk factors of cancer.

CONCLUSIONS

Regardless of considerable disparities in incident cancer attributable to modifiable risk factors across industries, the total incident cancer rate was elevated in all industries in both sexes.

The Epidemiological Surveillance of Mesothelioma Mortality in Italy as a Tool for the Prevention of Asbestos Exposure

As part of a surveillance plan active since the early 1990s, this study evaluates malignant mesothelioma (MM) mortality for the time-window 2010-2019 in Italy, a country that banned asbestos in 1992. National and regional mortality rates for MM, and municipal standardized mortality ratios (all mesotheliomas, pleural (MPM) and peritoneal (MPeM)), by gender and age group were calculated. A municipal clustering analysis was also performed. There were 15,446 deaths from MM (11,161 males, 3.8 × 100,000; 4285 females, 1.1 × 100,000), of which 12,496 were MPM and 661 were MPeM. In the study period, 266 people ≤50 years died from MM. A slightly decreasing rate among males since 2014 was observed. The areas at major risk hosted asbestos-cement plants, asbestos mines (chrysotile in Balangero), shipyards, petrochemical and chemical plants, and refineries. Female mortality excesses particularly were found in municipalities with a fluoro-edenite-contaminated mine (Biancavilla) and textile facilities. Excesses were also found in a region with the presence of natural asbestos fibres and in males living in two small islands. The Italian National Prevention Plan stated recommendations to eliminate asbestos exposures and to implement health surveillance and healthcare for people exposed to asbestos.

Laying the Foundation for a Mesothelioma Patient Registry: Development of Data Collection Tools

Mesothelioma, a cancer of mesothelial cells that line the chest, lungs, heart, and abdomen, is a relatively rare disease. In the United States, approximately 3000 individuals are diagnosed with mesothelioma annually. The primary risk factor for mesothelioma is occupational asbestos exposure which can occur decades prior to disease development, though in approximately 20% of cases, known asbestos exposure is lacking. While several other countries have developed mesothelioma registries to collect key clinical and exposure data elements to allow better estimation of incidence, prevalence, and risk factors associated with disease development, no national mesothelioma registry exists in the U.S. Therefore, as part of a larger feasibility study, a patient exposure questionnaire and a clinical data collection tool were created using a series of key informant interviews. Findings suggest that risk factor and clinical data collection via an on-line questionnaire is feasible, but specific concerns related to confidentiality, in the context of employer responsibility for exposure in the unique U.S. legal environment, and timing of enrollment must be addressed. Lessons learned from piloting these tools will inform the design and implementation of a mesothelioma registry of national scope.

Modifiable risk factors and cancer mortality in transport, rescue, and security industries

PURPOSE

We investigated the risk of mortality from cancers attributable to modifiable risk factors across representative transport, rescue, and security industries.

METHODS

We used nationwide Danish registries to identify all 307,605 workers from these industries from 2001 through 2015 and 2,278,363 other economically active individuals aged 18-64 years at the baseline for comparison. Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for site-specific cancer deaths were calculated using Cox regression. Site-specific cancers were categorized by using population-attributable fraction (PAF) estimates derived from the previous literature.

RESULTS

During an average follow-up of 12.8 years, 5977 cancer deaths were registered in these industries. Cancer mortality with a high proportion of avoidable deaths (i.e., high PAF) was elevated in male seafarers (1.37; 1.16-1.62), in men of land transport (1.44; 1.35-1.52), in women of land transport (1.51; 1.29-1.77), and in women of defense forces (1.43; 1.13-1.81). In contrast, cancer mortality with a high PAF was reduced in men of police force (0.63; 0.51-0.78). The total cancer mortality was higher in seafarers (1.24; 1.12-1.37), workers in land transport (1.31; 1.27-1.36), and workers in defense forces (1.14; 1.07-1.22).

CONCLUSIONS

We observed considerable cancer mortality disparities associated with modifiable risk factors across transport, rescue, and security industries.

Asbestos and Other Hazardous Fibrous Minerals: Potential Exposure Pathways and Associated Health Risks

There are six elongate mineral particles (EMPs) corresponding to specific dimensional and morphological criteria, known as asbestos. Responsible for health issues including asbestosis, and malignant mesothelioma, asbestos has been well researched. Despite this, significant exposure continues to occur throughout the world, potentially affecting 125 million people in the workplace and causing thousands of deaths annually from exposure in homes. However, there are other EMPS, such as fibrous/asbestiform erionite, that are classified as carcinogens and have been linked to cancers in areas where it has been incorporated into local building materials or released into the environment through earthmoving activities. Erionite is a more potent carcinogen than asbestos but as it is seldom used for commercial purposes, exposure pathways have been less well studied. Despite the apparent similarities between asbestos and fibrous erionite, their health risks and exposure pathways are quite different. This article examines the hazards presented by EMPs with a particular focus on fibrous erionite. It includes a discussion of the global locations of erionite and similar hazardous minerals, a comparison of the multiple exposure pathways for asbestos and fibrous erionite, a brief discussion of the confusing nomenclature associated with EMPs, and considerations of increasing global mesothelioma cases.