Occupation and risk of malignant pleural mesothelioma: A case-control study in Spain

BACKGROUND: The association of mesothelioma and asbestos exposure is well known, but some data suggest that probably many people are still being exposed to asbestos without knowing it. METHODS: Between 1993 and 1996, 132 cases (77% males) of histologically confirmed malignant pleural mesothelioma and 257 controls, residents in two provinces of Spain (Barcelona and C?adiz), were interviewed. They were classified according to their probability and intensity of occupational asbestos exposure by a panel of industrial hygienists, based on a detailed occupational history. RESULTS: Age and sex-adjusted odds ratio (OR) for the highest probability of exposure to asbestos was 13.2 (95% confidence interval 6.4-27.3), and 27.1 (9. 28-79.3) for high intensity. A dose-response trend was observed for both, probability and intensity. Overall, 61% of cases and 42% of controls had ever worked in an occupation with risk of asbestos exposure, with an OR of 2.59 (1.60-4.22). In our population 62% of cases could be attributed to occupational asbestos exposure. CONCLUSIONS: A high risk of pleural mesothelioma due to occupational asbestos exposure is confirmed, but there is still a sizeable proportion for which no evidence of occupational exposure was found. Most of these cases could be due to other sources of asbestos exposure, mainly domestic or environmental.     

Clinical study of asbestos-related lung cancer

We analyzed the characteristics of 120 patients of primary lung cancer supposed to be induced by exposure to asbestos. Most of 120 patients were male and the age ranged from 47 to 87 years with a median of 70 years. No particular tendency was observed in the histological types of the lung cancer in 120 patients. Forty of the 120 patients were heavy smokers. When the occupational history was analyzed, most of the patients had been exposed to asbestos in former Japanese naval shipyard, commercial shipyards, construction industry and ironworks. The term of asbestos exposure was 2 to 60 years with a median 27 years. Lung cancers appeared after 15 to 69 years with a median 43 years from the initial exposure to asbestos. Lung cancer was accompanied by asbestosis in 35 patients and by pleural plaques in 77. Twenty-two patients had both asbestosis and pleural plaques. The number of asbestos bodies per 5 g wet lung tissue for 72 patients whose lung tissues obtained from autopsy or surgery was more than 150 bodies which meant the number of occupational asbestos exposure. As for the kinds of asbestos fibers of 32 patients, 14 patients exposed to crocidolite, 10 patients to amosite and 8 patients to chrysotile.     

Epidemiologic investigation of respiratory effects related to environmental exposure to asbestos inside insulated buildings

The respiratory effects of environmental pollution by asbestos inside university buildings were studied by comparing radiographic, clinical, and functional parameters among three groups of workers with different levels of exposure. Eight hundred and twenty-eight (828) people who worked for at least 15 yr in asbestos-insulated buildings and who were without known occupational exposure to asbestos (environmentally exposed group [EE]) were compared to a group of 252 workers with occupational exposure (occupationally exposed group [OE]), used as positive control; and to a group of 350 people with no known exposure to asbestos (nonexposed group [NE]), within the same university. After adjustment for confounding variables, no differences could be seen between groups EE and NE. Group OE exhibited a higher prevalence of pleural changes and lower lung functions than groups EE and NE.     

Lung cancer in a female non-smoker with occupational exposure to asbestos: a case report

BACKGROUND: Until recently, asbestos was widely used in a variety of industrial processes. Workers exposed to asbestos may develop lung and pleural diseases such as asbestosis, lung cancer, benign pleural effusion, pleural plaques and mesothelioma. OBJECTIVE: To describe a clinical case of lung cancer in a female non-smoker with occupational exposure to asbestos. METHODS: The clinical and occupational history was based on the information kindly provided by the Occupational Unit of the National Health Service and on the case history of a hospital admittance in 2001, when the patient underwent surgery for lung cancer. RESULTS: The patient worked for 6 years in an asbestos manufacturing industry where she was exposed to high concentrations of asbestos, and then worked for 14 years in a sugar refinery only during the summer. She had benign pleural effusion, pleural plaques, asbestosis and lung cancer. CONCLUSIONS: We concluded that a six-year exposure to high doses of asbestos may induce lung cancer and asbestosis in a female non-smoker.     

Five cases of pleural mesothelioma with endemic pleural calcifications in a rural area in Greece.

The authors describe 5 cases of pleural mesothelioma in a rural population of Macedonia, Greece. This population had been covered by an X-ray study over a 3-year period to detect pleural calcifications compatible with asbestos exposure. The study revealed a 24.2% prevalence of pleural plaques among the inhabitants aged over 40 years of 7 rural villages. High contents of asbestos (chrysotile and tremolite)--up to 90% by volume--were found in the material that was used for whitewashing the houses up to 1935. Even now, environmental concentrations of 0.01 fibres/ml were recorded in the houses. The prevalence of pleural mesothelioma in this rural population is high compared to the general population. A possible explanation of the phenomenon may be a cumulative environmental exposure to asbestos which, even though presumably within the acceptable limits for occupational exposure, lasted over a much longer time period, in terms of both daily exposure and total duration.     

Environmental exposure to asbestos in the area around Goor has been established as the cause of pleural mesothelioma in women

OBJECTIVE: To determine whether a disease cluster of 22 additional cases of pleural mesothelioma among women could be attributed to environmental asbestos exposure due to asbestos fibers from waste material on roads and property yards. The women studied were observed in an area with substantial environmental exposure to asbestos during the period 1989-2002. DESIGN: Ecological study. METHOD: In the study period of 1989-2002, all cases of mesothelioma among women, based on a strict histopathologic definition, occurring in the region of Twente, The Netherlands (n = 59) were provided by the regional cancer register. Additional information was collected on the occupational histories of the cases and their partners and addresses of residence through medical records, general practitioners, and next-of-kin. Environmental asbestos exposure was assigned to all cases that had had a long-term stay in a house in the area around Goor with demonstrated local environmental asbestos pollution and where any contact with asbestos through occupation or in the household had been excluded. RESULTS: In the risk area around Goor, out ofa total of 28 cases ofwomen with pleural mesothelioma, asbestos in the environment was found to be the only source of asbestos exposure for to women. In a further 4 women, environmental asbestos exposure was found to be the most likely cause of pleural mesothelioma. The average cumulative exposure was around 0.11 fiber/ml x exposure years. The observed extra incidence of 22 cases was attributed to the environmental exposure to asbestos in 64% (14/22) of cases. CONCLUSION: The environmental pollution to asbestos waste materials in the area around Goor was the main cause of the strongly increased incidence of pleural mesothelioma among women in this area. Taking into account an equal risk among men, the consequences of asbestos exposure in the area around Goor in the next 25 years are likely to result in 2 cases of pleural mesothelioma each year.     

Malignant mesothelioma from neighborhood exposure to anthophyllite asbestos

BACKGROUND: Anthophyllite asbestos has been reported to cause asbestosis, lung cancer, mesothelioma, and pleural plaques in occupationally exposed workers. Anthophyllite has also been associated with pleural plaques in Finland and Japan among those who live near mines and mills and have neighborhood or environmental exposure. METHODS: We evaluated a 38-year-old patient with pleural mesothelioma who lived, attended school, and delivered newspapers near a manufacturing facility that used exclusively anthophyllite asbestos fiber from ages 8-17 years. He had no work exposure to asbestos. RESULTS: The pleural mesothelioma was an epithelial type with tubulopapillary structures and was treated with an extrapleural pneumonectomy followed by radiation therapy. The malignant cells were positive by immunohistochemistry for cytokeratin but negative for carcinoembryonic antigen, S100, B72.3, and leu M1 antigen. Anthophyllite fibers were > 5 microm in length in lung tissue compared to 3 microm from a general population study. CONCLUSIONS: Anthophyllite asbestos has been associated with neighborhood environmental exposure and pleural plaques; we now report a neighborhood exposure and pleural mesothelioma.     

Asbestos-related lung cancer and mesothelioma in Japan

In Japan, crocidolite had been used for asbestos cement pipe and spraying, and amosite had been used for building board and spraying. These two types of asbestos had stopped to use in Japan in the late 1970s. An extreme increase in imported asbestos (all 3 commercial types) was observed between 1960 and 1974. In 1960, 77,000 tons of asbestos were imported, and reached the peak as 352,316 tons in 1974. This extreme rise of asbestos imports corresponds with the recent rapid increase in mortality of malignant pleural mesothelioma. Between 1995 and 1999, an estimated mean annual death from pleural mesothelioma was about 500. The annual number of compensated occupational respiratory cancers due to asbestos exposure has also been increasing. Up to the end of March 2000, 162 cases with malignant mesothelioma and 197 cases with lung cancer were compensated. As for lung cancer, epidemiological studies are scanty in Japan. Limited environmental data of the working places in asbestos textile factories suggests that heavy asbestos exposure in the past made deaths from respiratory diseases. Less asbestos exposure will enable exposed workers to survive enough to reach cancer age. Even now smoking rate among males in Japan are over 50%. So lung cancer deaths caused by the interaction between smoking and asbestos exposure will be continuing.     

Respiratory health in Turkish asbestos cement workers: the role of environmental exposure

AIM: Benign and malignant pleural and lung diseases due to environmental asbestos exposure constitute an important health problem in Turkey. The country has widespread natural deposits of asbestos in rural parts of central and eastern regions. Few data exists about the respiratory health effects of occupational asbestos exposure in Turkey. A cross-sectional study was conducted to investigate respiratory health effects of occupational asbestos exposure and the contribution of environmental asbestos exposure. METHODS: Investigations included asbestos dust measurements in the workplace and application of an interviewer-administered questionnaire, a standard posteroanterior chest X-ray and spirometry. Information on birthplace of the workers was obtained in 406 workers and used to identify environmental exposure to asbestos, through a map of geographic locations with known asbestos exposure. RESULTS: Asbestos dust concentration in the ambient air of the work sites (fiber/ml) ranged between 0.2 and 0.76 (mean: 0.25, median: 0.22). Environmental exposure to asbestos was determined in 24.4% of the workers. After the adjustment for age, smoking, occupational asbestos exposure, and potential risk factors environmental asbestos exposure was associated with small irregular opacities grade > or = 1/0 (44.2% vs. 26.6%, P < 0.01), FVC% (97.8 vs. 104.5, P < 0.0001), and FEV1% (92.4 vs. 99.9, P < .0001). Occupational exposure to asbestos was associated with small irregular opacities grade > or = 1/0 (OR: 2.0, 95% CI: 1.3-3.1, per 1 unit increase in the natural logarithm of fiber/ml) and FEV1/FVC% (beta: 1.1, SEM: 0.54; P < 0.05, per 1 unit increase in the natural logarithm of fiber/ml). CONCLUSIONS: Environmental exposure to asbestos could increase the risk of asbestosis and lung function impairment in workers occupationally exposed to asbestos, independent from occupational exposure and smoking.     

Asbestos-related mesothelioma in monfalcone,Italy

The Monfalcone area, in northeastern Italy, is a small industrial territory (population about 60,000), with a large shipyard. Between October 1979 and April 1992, ninety-two malignant mesotheliomas were diagnosed at the Monfalcone Hospital. The series included 84 men and 8 women, aged 42 to 89 years (median age 68 years). There were 89 pleural and 3 peritoneal tumors. Seventy patients (69 men and 1 woman) had worked in the shipyards; six were seamen, and four insulators. Five men had been exposed to asbestos in various industries; six women had histories of domestic exposure, and one woman had a history of possible environmental exposure. The latency periods (intervals between first exposure to asbestos and diagnosis of the tumor) ranged from 20 to 65 years (median 52 years). Latency periods among insulators were significantly lower than among shipyard workers, as well as lower than among the other categories (p<0.01). Lung asbestos bodies were isolated after chemical digestion in 73 cases at necropsy, and in two cases at surgery. In necropsy cases, asbestos body burdens ranged between 100 and 10,000,000 bodies per gram of dried tissue (median 11,000). Pleural plaques were observed at necropsy in 62 out of 73 cases, and in two cases at surgery. In the time period we considered, the annual incidence rates for pleural mesothelioma were very high among male Monfalcone residents, being 189 per 100,000 among people aged 75 years or more. On the basis of occupational data and of objective signs (lung asbestos bodies, pleural plaques), all the cases of the present series but one (that with possible environmental exposure) were considered as asbestos-related. The role of co-factors in the development of asbestos-related mesothelioma is suggested. © 1993 Wiley-Liss, Inc.     

Pleural mesothelioma in Sweden: an analysis of the incidence according to the use of asbestos

OBJECTIVE: To investigate if the preventive measures taken to reduce the occupational exposure to asbestos have resulted in a decreased incidence of pleural mesothelioma in Sweden. METHODS: The incidence of pleural mesothelioma between 1958 and 1995 for birth cohorts born between 1885 and 1964 was investigated. The cases of pleural mesothelioma were identified through the Swedish Cancer Register. RESULTS: In 1995, around 80 cases of pleural mesothelioma could be attributed to occupational exposure to asbestos. There is an increasing incidence in more recent birth cohorts in men. The incidence was considerably higher in the male cohort born between 1935 and 1944 than in men born earlier. CONCLUSIONS: The annual incidence of pleural mesothelioma attributable to occupational exposure to asbestos is today larger than all fatal occupational accidents in Sweden. The first asbestos regulation was adopted in 1964 and in the mid 1970s imports of raw asbestos decreased drastically. Yet there is no obvious indication that the preventive measures have decreased the risk of pleural mesothelioma. The long latency indicates that the effects of preventive measures in the 1970s could first be evaluated around 2005.     

Cluster of malignant mesothelioma cases in a thermostat manufacturing industry

BACKGROUND: Malignant mesothelioma is a rare disease and the identification of a cluster of cases suggests a possible presence of an asbestos contamination source. OBJECTIVES: To describe 3 cases of malignant mesothelioma (2 pleural and 1 peritoneal) that occurred in workers employed in the same thermostat factory. METHODS: Since this occupational sector is not traditionally known for asbestos exposure the Lombardy Mesothelioma Registry proposed to Local Occupational Health Unit to investigate this industry. RESULTS: From the first inspection of the plant, an environmental asbestos contamination (ropes covering oven handle and gasket) was found. But the greatest source of exposure was identified in the melamine resin reinforced with asbestos that constituted some internal parts of thermostats and that were sheared and perforated by the workers. So the 3 cases were defined as occupational diseases and legal procedures were initiated. CONCLUSION: The results underline the importance of a close cooperation within Local Occupational Health Units and Mesothelioma Registry in the identification and evaluation of asbestos occupational exposure otherwise not recognized, determining thus the loss of precious information.     

Malignant mesothelioma of the pleura in a truck driver

BACKGROUND: Among the responsibilities of the health operators in the occupational health and safety services of the local health units in Lombardy (Italy) is the administration of standardized questionnaires for the investigation of possible occupational exposure to asbestos fibres in subjects diagnosed with malignant mesothelioma. OBJECTIVES: To describe a case of malignant mesothelioma in a truck driver suspected of being occupationally exposed to asbestos during the course of administration of the questionnaire. METHODS: Analysis of the literature regarding asbestos contamination of truck cabs. Some years ago Italian authors described a case of asbestosis in a truck-driver and findings of pollution by asbestos fibres in the cabs of some models of trucks. RESULTS: The subject had worked for more than 30 years as a truck driver operating on long distances on truck models described in literature as contaminated by asbestos fibres. He had not transported materials made of asbestos, and had not carried out maintenance on the trucks, nor had he any non-occupational sources of exposure to asbestos. Thus the mesothelioma was related to occupational exposure and procedures were initiated for reporting a suspected occupational disease.     

Investigation of micronucleus frequencies in lymphocytes of inhabitants environmentally exposed to chrysotile asbestos

Exposure to asbestos minerals has been associated with a wide variety of adverse health effects including lung cancer, pleural mesothelioma, and cancer of other organs. Many of the regions of Turkey have asbestos deposits. People in Do?anl? village – one of these regions – have been environmentally exposed to chrysotile asbestos since they were born. In this study the effects of asbestos on micronucleus (MN) frequencies of inhabitants exposed to chrysotile asbestos have been examined. Thirty subjects who had been environmentally exposed to chrysotile asbestos and living in Do?anl? village, and 25 controls were studied to assess the MN frequency. The control group was selected from healthy individuals with no exposure to asbestos and living in similar geographic conditions to Do?anl? village. Peripheral blood samples were collected from each subject and cultured for MN assay. Cytochalasin-B was added to lymphocyte cultures for evaluation of MN in binucleated (BN) cells. The differences between those exposed to chrysotile asbestos and controls were not statistically significant in terms of BN cells with MN (p > 0.05). There was not a significant relationship between MN frequencies and age, sex, smoking, both in chrysotile asbestos-exposed subjects and in controls (p > 0.05). Although the detection of calcified pleural plaques found in the inhabitants has indicated environmental exposure to chrysotile asbestos, our results show that chrysotile asbestos was not an inducer of MN in subjects exposed to chrysotile asbestos.     

Pleural plaques and exposure to mineral fibres in a male urban necropsy population.

OBJECTIVES--The study aimed to evaluate the risk of pleural plaques according to the degree of past exposure to asbestos, type of amphibole asbestos, and smoking, as well as to estimate the aetiologic fraction of asbestos as a cause of plaques among urban men. METHODS--The occurrence and extent of pleural plaques were recorded at necropsies of 288 urban men aged 33 to 69 years. The pulmonary concentration of asbestos and other mineral fibres was analysed with scanning electron microscopy. The probability of past exposure was estimated from the last occupation. RESULTS--Pleural plaques were detected in 58% of the cases and their frequency increased with age, probability of past occupational exposure to asbestos, pulmonary concentration of asbestos fibres, and smoking. The risk of both moderate and widespread plaques was raised among asbestos exposed cases, and the risk estimates were higher for widespread plaques than for moderate plaques. The age adjusted risk was higher for high concentrations of crocidolite/amosite fibres than for anthophyllite fibres. The aetiologic fraction of pulmonary concentration of asbestos fibres exceeding 0.1 million fibres/g was 43% for widespread plaques and 24% for all plaques. The median pulmonary concentrations of asbestos fibres were about threefold greater among cases with widespread plaques than among those without plaques. No increased risk of pleural plaques was associated with raised total concentrations of non-asbestos fibres. CONCLUSION--The occurrence of pleural plaques correlated closely with past exposure to asbestos. The risk was dependent on the intensity of exposure. Due to methodological difficulties in detecting past exposures to chrysotile and such low exposures that may still pose a risk of plaques, the aetiologic fractions calculated in the study probably underestimate the role of asbestos.     

Pleural malignant mesothelioma and non-occupational exposure to asbestos in Casale Monferrato, Italy.

OBJECTIVES--To assess and quantify the occurrence of pleural malignant mesotheliomas in people who neither experienced occupational exposure to asbestos nor were married to (or known to live with) workers exposed to asbestos in the workplace. The study was conducted in the area of the local health authority of Casale Monferrato, in north western Italy, where a large factory that produced asbestos cement was active up to 1985. No other major activities related to asbestos have ever been present in the area. METHODS--A retrospective survey covering the period 1980 to 1991 identified 126 incident pleural malignant mesotheliomas histologically diagnosed among residents in the local health authority (population at the 1981 census 98,000). Submission of 83 of 95 cases diagnosed during 1980-9 for revision by a panel of five expert pathologists led to the exclusion of 21. The 31 cases diagnosed in 1990-1 were not submitted for revision. For 64 of the 105 retained cases, information derived from different sources (rosters of the employees in the asbestos cement factory dated back to 1907, list of their spouses, clinical records) did not suggest occupational or paraoccupational exposure to asbestos. RESULTS--Incidence excludes cases for which there was some suggestion of occupational or paraoccupational exposure to asbestos. Incidence of histologically confirmed malignant mesothelioma among residents in the local health authority (annual x 100,000; age adjusted) was 4.2 in men and 2.3 in women (based on 26 and 18 cases respectively). In both sexes, rates in 1985-9 were higher than in the previous quinquennium. Corresponding estimates for 1990-1 (based on unrevised diagnoses) suggest similar rates in men and women. CONCLUSION--Rate ratios which are four to six times those measured by conventional Italian cancer registries can hardly be totally explained by bias produced by lack of recognition of occupational or paraoccupational exposure. The problem of proving this type of negative data is common to other circumstances of alleged cancer clusters of environmental (non occupational) origin.     

Asbestos lung burden and asbestosis after occupational and environmental exposure in an asbestos cement manufacturing area: a necropsy study

OBJECTIVE: The largest Italian asbestos cement factory had been active in Casale Monferrato until 1986: in previous studies a substantial increase in the incidence of pleural mesothelioma was found among residents without occupational exposure to asbestos. To estimate exposure to asbestos in the population, this study evaluated the presence of histological asbestosis and the lung burden of asbestos fibres (AFs) and asbestos bodies (ABs). METHODS: The study comprises the consecutive series of necropsies performed at the Hospital of Casale Monferrato between 1985 and 1988. A sample of lung parenchima was collected and stored for 48 out of 55 necropsies. The AF concentration was measured with a TEM electron microscope with x ray mineralogical analysis. The ABs were counted and fibrosis evaluated by optical microscopy. The nearest relative of each subject was interviewed on occupational and residential history. Mineralogical and histological analyses and interviews were conducted in 1993-4. RESULTS: Statistical analyses included 41 subjects with AF, AB count, and interview. Subjects without occupational exposure who ever lived in Casale Monferrato had an average concentration of 1500 AB/g dried weight (gdw); Seven of 18 presented with asbestosis or small airway lung disease (SAL). G2 asbestosis was diagnosed in two women with no occupational asbestos exposure. One of them had been teaching at a school close to the factory for 12 years. Ten subjects had experienced occupational asbestos exposure, seven in asbestos cement production: mean concentrations were 1.032 x 10(6) AF/gdw and 96,280 AB/gdw. Eight of the 10 had asbestosis or SAL. CONCLUSION: The high concentration of ABs and the new finding of environmental asbestosis confirm that high asbestos concentration was common in the proximity of the factory. Subjects not occupationally exposed and ever living in Casale Monferrato tended to have higher AB concentration than subjects never living in the town (difference not significant). The concentrations of ABs and AFs were higher than those found in other studies on nonoccupationally exposed subjects.

 

     

Urinary asbestos fibers and inorganic particles in past asbestos workers

To assess the validity of the procedure as a test of asbestos exposure, we compared urinary asbestos fibers with occupational and environmental exposure data in a random sample of 48 subjects with high past asbestos exposure. Occupational and environmental exposure was estimated on questionnaire, pleural plaques were diagnosed with computed tomography, and inorganic fibers and particles were identified by scanning electron microscope with an energy-dispersive spectrometry. Few urinary asbestos fibers (in 15% of workers and 17% of cases with pleural plaques) and high amount of urinary silicate (particularly nonfibrous particles) were detected. Asbestos undergoes dissolution in lung tissues, but the secondary minerals are largely unknown. These materials, possibly nonfibrous silicates or metals, could be excreted with urine. Therefore, another study including a control group is warranted to discriminate the occupational origin of minerals in the urine.     

Malignant mesothelioma in the industrial area of Colleferro

The study describes the occurrence of pleural and peritoneal malignant mesothelioma in the Colleferro industrial area (Province of Rome, 9 municipalities, population 63,000, period 1993-98) which is the site of a large chemical plant (BPD) producing organic chemicals, acid mixtures, insecticides, explosives and dynamite, and was involved in manufacturing/maintenance of railroad rolling stock. Asbestos was extensively used in these plants in the past. Mesothelioma cases were actively searched from data in files of pathology archives, hospital admission and discharge (records), and death certificates recorded at local health authority register. 23 potential cases were identified for whom clinical charts and pathological slides were reviewed. A multidisciplinary evaluation of all collected information confirmed 18 cases of cyto-histologically proven malignant mesothelioma (pleural/peritoneal ratio of 2.75:1) among residents and/or workers at BPD. The remaining 5 cases were defined as not mesothelioma; however, two were cases of lung cancer (both occupationally exposed to asbestos). All subjects with malignant mesothelioma had been occupationally exposed to asbestos (14 males and 3 females), except one (1 female with domestic exposure). No mesothelioma case was attributable to environmental exposure. Of the 17 cases with occupational asbestos exposure, 15 occurred in BPD workers employed in manufacturing/maintenance of railroad rolling stock (3 cases), general maintenance services (5 cases), or in the armaments sector (7 cases) and 2 in residents but not BPD workers (1 baker, 1 pipefitter). The incidence rate in residents of the 9 municipalities was 5.5 in males and 1.3 in females (standardized on the Italian population x100,000, census 1981). For Colleferro municipality only, the incidence was 10.1 in males and 4.1 in females, which are the highest rates reported so far in Italy. Besides confirming the risk of mesothelioma risk in railroad rolling stock manufacturing and asbestos-insulated pipe maintenance workers, this study identifies a cluster of malignant mesothelioma in explosives production workers.     

Assessment of asbestos exposure, mortality study, and health intervention in workers formerly exposed to asbestos in a small factory making drying machines for textile finishing and the paper mill industry in Pistoia, Italy

BACKGROUND AND OBJECTIVES: Three malignant pleural mesotheliomas occurred among workers of a small factory that manufactured drying machines for the textile and paper mill industries using asbestos cement (crocidolite, amosite and chrysotile) as insulating panels. The Occupational Medicine Unit of the Local Health Unit of Pistoia, Italy, carried out an intervention programme in the plant in order to 1) assess past asbestos exposure via analysis of the fibre content of samples from drying machines, and of dust samples collected in the factory. Information on the characteristics of occupational exposure was also collected; 2) investigate cancer mortality by means of a mortality study of the employees and, 3) carry out a health intervention programme in workers formally exposed to asbestos in the past. METHODS: Samples from the drying machines and dust samples collected in the factory were analysed using X-ray diffractometric methods. Information on the characteristics of occupational exposure were collected by interviewing plant workers. Two-hundred and fifty employees who had worked in the factory between 1962 and 2000 were included in the mortality study. Follow-up was performed from 1962 to 2002. Health intervention in workers exposed to asbestos in the past involved general practitioners and occupational physicians (first level medical examinations); pneumologists and radiologists (second level medical examinations) of the local health unit. RESULTS: Asbestos fibres were found both in samples from drying machines and in dust samples collected in the factory. Interviews with workers showed that asbestos exposure varied considerably. The SMR for mesothelioma and lung cancer in 234 male workers were 37.0 (95%CI: 4.47-130.0), and 1.29 (95%CI: 0.26-3.78), respectively, based on mortality rates for Tuscany region. Sixty-two workers underwent first level medical examinations; 57 second level examinations. Chronic obstructive lung disease was found in 3 workers; restrictive lung disease was found in 3 employees, one of whom had pleural plaques. CONCLUSIONS: Further investigation is needed in order to identify unknown asbestos exposures in small metal engineering factories.