Tuscany mesothelioma registry (1988-2000): evaluation of asbestos exposure

BACKGROUND: The Tuscany Mesothelioma Register (ARTMM) records pleural malignant mesothelioma cases of Tuscany residents, diagnosed by histological, cytological, or clinical (radiography or computerized tomography) examinations. The ARTMM began in 1988 and estimates mesothelioma incidence in Tuscany and collects information on past asbestos exposure of mesothelioma cases. OBJECTIVES: The aim of this paper was to describe the incidence of pleural mesothelioma cases in Tuscany and to analyse their possible past asbestos exposures. METHODS: We considered pleural mesothelioma cases recorded in ARTMM in the period 1988-2000 and interviews collected for these cases. In order to identify past asbestos exposure in the occupational and non-occupational history of patients, interviews were carried out using a standardised questionnaire. RESULTS: In the period 1988-2000, 494 pleural malignant mesothelioma cases were recorded in the ARTMM; 82% were males. In the periods 1988-1993, 1994-1997, 1998-2000 the incidence rates, standardised on the Italian population (per 100,000), were respectively 1.15, 1.57, 2.58 among males; 0.29; 0.27; 0.29 among females. Information on occupational history was collected for 418 mesothelioma patients (85% of recorded cases): 173 mesothelioma cases were directly interviewed; for 245 cases relatives or work colleagues were interviewed. Occupational asbestos exposure was ranked as certain, probable or possible in 72% of the interviewed cases (80% of males; 20% of females). Environmental and non-occupational asbestos exposure was identified in 1% of males, and 3% of females. In 24% of the interviewed cases (15% of males; 74% of females) no known asbestos exposure was identified. Occupational asbestos exposure occurred in maritime activities (shipyards, dock work, merchant and regular Navy), the building industry, railway carriage construction and maintenance, rail transport, textile industries (mainly rag sorting), electricity production, asbestos cement manufacture, chemical, iron and steel industries and in glass manufacturing. In Tuscany two areas are distinguished for their well-documented and massive use of asbestos: the coastal areas (Livorno and Massa Carrara) for maritime activities, and the areas of Pistoia and Arezzo for railway carriage construction and repair. Mesothelioma incidence rates in these areas are the highest in the whole region. CONCLUSIONS: Further investigation is needed in order to identify unknown asbestos uses and consequent exposure, in particular for females. Uncertainty as regards occurrence of asbestos exposure persists in the textile industries where the mesothelioma epidemics have not yet declined. Research hypotheses are addressed on the re-use of jute bags previously containing asbestos, therefore collection of further information on periods and methods of this recycling activity is essential.     

Malignant mesothelioma in Basse-Normandie, a French population study. Descriptive analysis, prognostic factors and survival

BACKGROUND: Malignant mesothelioma is a pleural and/or peritoneal tumor closely related to asbestos exposure, and its incidence should continue to increase during the first two decades of the 21(rst)century. The main prognostic factors described for this tumor are older age, sex, tumor stage and histological type. The aim of this study was to assess the incidence of pleural and peritoneal malignant mesothelioma in the County of Basse-Normandie (France), as well as their epidemiological characteristics, and the prognostic factors related to survival duration. METHODS: Cases were identified through repeated inquiries among all chest physicians and pathologists of the County of Basse-Normandie. A special care was taken in the validation of the diagnosis of each case. Incidence of mesothelioma was determined according to sex and age (5 years categories). Qualitative and quantitative variables were compared with the use of chi-square or Student's t tests respectively. Survival rate was calculated by Kaplan-Meier method, and prognostic factors were studied by means of Cox model. RESULTS: Study population consisted in all 80 malignant mesothelioma cases diagnosed in Basse-Normandie between the 1(rst) of September 1995 and the 31(rst) of August 1999. Annual incidence rates of pleural mesothelioma were 1.1/100 000 in men and 0.23/100 000 in women; annual incidence rates for peritoneal mesothelioma were 0.21/100 000 in men and 0.13/100 000 in women. Asbestos exposure was present in 63 cases (78.8%). The study of geographic distribution of mesothelioma cases revealed the influence of the main asbestos industrial settings, as well as the numerous scattered cases related to other occupational exposure. Mean survival duration was 9 months for pleural mesothelioma and 5 months for peritoneal mesothelioma. After adjustment on age, death risk was higher in asbestos-exposed than in non asbestos-exposed cases. CONCLUSION: This study confirms that malignant mesothelioma is closely related to asbestos exposure, but not only in main asbestos industrial settings. It suggests that asbestos exposure may take place among prognostic factors of this tumor.     

Malignant mesothelioma: global incidence and relationship with asbestos

Mesothelioma incidence varies markedly from one country to another. The highest annual crude incidence rates (about 30 cases per million) are observed in Australia, Belgium, and Great Britain. A lot of data indicate a relationship between mesothelioma and asbestos. The hot areas for mesothelioma exactly correspond to the sites of industries with high asbestos use, such as shipbuilding and asbestos-cement industry. However, in many countries with high asbestos consumption, mesothelioma incidence is low. The reasons for this fact are not clear. The latency periods elapsing between first exposure to asbestos and development of mesothelioma are mostly longer than 40 yr. An inverse relationship exists between intensity of asbestos exposure and length of the latency period. Mesothelioma generally develops after long-time exposures to asbestos. Some recent studies show that the risk increases with the duration of exposure. Possible co-factors in the pathogenesis of asbestos-related mesothelioma include genetic predisposition, diets poor in fruit and vegetables, viruses, immune impairment, recurrent serosal inflammation. The study of co-morbidity in mesothelioma could give an insight into the pathogenesis of the tumor. While a levelling-off in mesothelioma incidence has been registered in some countries, a worsening of the epidemic is predictable in large parts of the world.     

Role of occupational asbestos exposure in Hungarian lung cancer patients

Objective: What is the frequency of occupational asbestos exposure among patients suffering from malignant respiratory tumours and how many of these tumours are associated with asbestos in Hungary? Methods: An internationally established questionnaire with 29 questions, covering the most characteristic activities of asbestos exposure at the workplace was completed for 300 patients with respiratory malignancies, i.e. 297 patients with lung cancer and three with mesothelioma of the pleura. From the questionnaire, the smoking habits were estimated and cumulative asbestos exposure was assessed in fibre-years. Additionally, lung X-rays were classified and the national data on the incidence of malignant pleura mesothelioma were analysed. Results: A cumulative asbestos exposure of 25?fibre-years or more was detected in 11 patients with lung cancer (4%) and in each of the three patients with pleural mesothelioma (100%). In a further 72 patients (24%), cumulative occupational asbestos exposure was assessed as below 25?fibre-years (between 0.01 and 23.9?fibre-years). In this group, car and truck mechanics, and installation and construction workers using asbestos-cement were registered. Among patients with an asbestos exposure of 25?fibre-years or more, six asbestos-cement production workers were observed, among them the three mesothelioma cases. A weak but significant association between positive X-ray findings and exposure estimates could be demonstrated. Additionally, results of the lung tissue fibre counts by scanning transmission electron microscopy were available for 25 of the lung cancer patients. A good correlation was observed between the asbestos fibre counts and the assessment of cumulative asbestos exposure. In Hungary, 84 cases of pleural mesothelioma were registered in 1997 and 73 in 1998. These numbers correspond to an annual incidence of about one new case per 100,000 inhabitants older than 15?years. Conclusions: The annual incidence of lung cancer in Hungary is about 6,000. Since in our series of lung cancer patients about 4% were observed, which could be accepted as representing occupational disease because of a cumulative exposure to 25?fibre-years or more, the annual asbestos related lung tumour incidences may be estimated to be approximately 150 or more. The proportion of nearly two estimated cases of lung cancer per case of pleural mesothelioma corresponds to international experience. Up to now, lung cancer cases only exceptionally have been registered as occupational diseases, i.e. they were seriously under-diagnosed in Hungary. For improving this situation, diagnostic assistance by a self-interview with a questionnaire covering the working history for all newly diagnosed lung cancer patients would be helpful.     

Occupational asbestos exposure and the incidence of non-Hodgkin lymphoma of the gastrointestinal tract: an ecologic study

PURPOSE: A previous case-control study observed a strong association between occupational exposure to asbestos and the incidence of non-Hodgkin lymphoma of the gastrointestinal tract (GINHL). To test this hypothesis, we sought to determine whether the geographic pattern of the incidence of GINHL in the US has paralleled that of mesothelioma. METHODS: Using data obtained from the nine US regions participating in the National Cancer Institute's Surveillance, Epidemiology and End Results program, we examined the incidence of malignancies among men ages 50 to 84 years between 1973 and 1984. RESULTS: The rates of mesothelioma, but not of GINHL, were about two times higher in the areas of Seattle and San Francisco, than in the other regions. Overall, there was no correlation between the rates of mesothelioma and of GIHNL (Pearson correlation coefficient-0.12, p = 0.77). CONCLUSIONS: This ecologic study finds no support for the hypothesis that occupational asbestos exposure is related to the subsequent incidence of GINHL.     

Mesothelioma in South Africa, 1976-84: incidence and case characteristics

Malignant mesothelioma is a rare tumour known to be associated with prior exposure to asbestos. Previous studies have described the occupational and clinical features of cases of mesothelioma in the Republic of South Africa (RSA) but none has set out to determine incidence of this disease. To estimate incidence, a case register was compiled for 1976-84 by contacting all medical practitioners and institutions likely to have seen cases of mesothelioma in this period; demographic, diagnostic and exposure details were sought. Cases were accepted if they provided evidence of histological diagnosis of mesothelioma. Fifty-two per cent of 1347 cases identified were in whites, 31% in blacks, 16% in coloureds and 1% in Asians. Seventy-three per cent of cases occurred in males. The majority of whites were aged 51-70 years, while the majority in other race groups were aged 41-60 years. The ratio of only pleural to only peritoneal mesothelioma was 11:1, although there were marked differences by race. Eighty-five per cent of males with exposure information available had prior exposure to asbestos, mostly occupational. A similar proportion of women had contact with asbestos but mostly through other types of exposure. Standardized incidence rates per million population aged 15 years and over were calculated for sex-race subgroups and were highest in white males (32.9 per million per year, 95% Cl 22.7-46.4), coloured males (24.8 per million per year, 95% Cl 16.2-36.9) and coloured females (13.9 per million per year, 95% Cl 7.7-23.5). These incidence rates are amongst the highest ever reported for a national population. Age-specific standardized incidence rates were highest in white males (over 100 per million per year in men over 55 years). Reasons for the differing rates by population group are likely to include differential access to health services. More rigorous control of asbestos exposure in the RSA is recommended.     

Asbestos and mesothelioma in Scotland

Summary A retrospective study of the incidence of mesothelioma in Scotland and its association with asbestos is described. For the years 1950–1967, 80 cases were traced from pathological reports and biopsy material of malignant tumours invading the peritoneum and pleura. Detailed histories of residence, occupation and degree of exposure to asbestos were obtained from relatives or friends for these 80 cases and also for two sets of controls matched for age and sex. The incidence of mesothelioma in Scotland was confirmed to be associated with exposure to asbestos and its incidence was shown to be similar to that in other areas of Britain.     

The epidermiologic relationship between pleural mesothelioma and asbestos exposure.

This paper describes an investigation of 85 notifications of either probable or possible mesothelioma to the Finnish Cancer Registry from 1953 through 1969. The investigation covers characteristic epidemiologic features and the possibility of the mesothelioma being connected with occupational or other exposure to asbestos. The incidence rate of pleural mesothelioma was estimated at 1.1 per million per year. The male/female ratio was 1.3:1, which greatly differed fsrom that for malignant neoplasms of the bronchus or lung in Finland in 1960. The mean age at dealth from mesothelioma was over 7 years lower than that for bronchial carcinoma. The ratio of the crude incidence rates for the urban and rural populations was 4.2; the corresponding ratio for cases of carcinoma oopulations was 4.2; the corresponding ratio for cases of carcinoma of the bronchus or lung was 1.2 in Finland in 1960. THE LAST OCCUPATIONS OF THE 82 DECEASED PERSONS, OBTAINED FROM THE DEATH CERTIFICATES, WERE DIVIDIED INTO THREE CATEGORIES ACCORDING TO POSSIBLE ASBESTOS EXPOSURE. Exposure was present or probable in 9 (11.0) cases, 28 (34.2 %) had a possible exposure, and in 33 (40.2 %) cases exposure was absent or unlikely. The occupation of 12 (14.6) persons was unknown. Additional information of possible exposure history was obtained by interviewing the relatives of 10 mesothelioma patients. For half of the persons a definite, although in some cases trivial, exposure to asbestos could be ascertained. For the other five persons no exposure, either occupational, neighborhood or domestic, to asbestos could be traced. The residental distribution of the 85 persons with mesothelioma revealed no clustering of cases.     

Estimates of pleural mesothelioma incidence in the Lazio region (Italy), 1997-2000

BACKGROUND: Malignant mesothelioma is indicative of past exposure to asbestos. In recent years an increase of incidence and mortality from malignant mesothelioma has been observed. Recent legislation in Italy requires nation-wide registration of asbestos-related pathologies. We conducted a preparatory study for systematic recording of cases of malignant pleural mesothelioma in the Lazio region. OBJECTIVES: To register new diagnoses of malignant mesothelioma, to estimate the incidence in the Lazio region, and to evaluate possible survey instruments. METHODS: We conducted a systematic study of hospital admissions in the region with diagnosis of cancer of the pleura (ICD-IX 163) in the period 1997-2000. Clinical information and results of diagnostic tests were requested for 530 patients from the hospitals involved. Using the capture-recapture method, it was possible to estimate the accuracy of the data we compiled using hospital admissions as the data source (76.8%, 95% C.I.=76.4-77.3). RESULTS: After careful review of clinical documentation, the diagnosis of malignant mesothelioma of the pleura was confirmed in 31.6% of cases (156 cases diagnosed). The percentage of confirmed cases has risen over the years (from 21% in 1997 to 45.1% in 2000) and it was higher in large public hospitals than in other types of health care facilities. On the basis of 156 confirmed cases of mesothelioma (116 males and 40 females), we estimated the annual incidence of the disease in the Lazio region as 1.73 new cases per 100,000 inhabitants among men and 0.47 new cases per 100,000 inhabitants among women. CONCLUSIONS: The results show that the incidence of mesothelioma in the region is consistent with national data, falling in the middle of the range for all Italian regions. However, some areas emerge (for example, Colleferro, Civitavecchia, Tarquinia, Ferentino, Gaeta, Aprilia, Pomezia) that have particularly high rates, probably in relation to past occupational asbestos exposure. The role of diffuse environmental exposure in Rome may warrant further investigation.     

Occupational exposure and regional variation of malignant mesothelioma in Norway, 1970-79

This investigation is based on a study of 117 men and 24 women with malignant mesothelioma registered by the Cancer Registry of Norway, 1970-79. The age-adjusted incidence rate in men for each county varied from 1.7 to 13.3 per million per year. Eighty-two percent of the men revealed possible occupational asbestos exposure. They were evenly distributed between counties with high and low mesothelioma incidence. Only 17% of the women had possible occupational asbestos exposure. Total lung fiber concentration was analyzed with scanning electron microscopy in 65 men and 13 women. The median lung fiber concentration in men was 2.4 million per gram of dried tissue (range less than 0.4-490), in women 1.0 million per gram (range less than 0.4-41), and in male controls less than 0.4 million per gram (range less than 0.4-4.8). The median year of first exposure was 1937 (range 1909-60) for men from counties with a high incidence rate and 1945 (range 1938-59) for men from counties with a low incidence rate. The counties with a high compared to a low incidence rate of malignant mesothelioma, 1970-79, showed an apparent difference in the percentage of population employed in industry in 1946. The regional variation in the incidence of malignant mesothelioma in men is mainly attributable to the proportion of population exposed to asbestos in industry per county prior the 1950s and the time since exposure started.(ABSTRACT TRUNCATED AT 250 WORDS)     

Malignant pleural mesothelioma in parts of Japan in relationship to asbestos exposure

Malignant pleural mesothelioma is induced by asbestos exposure. Many reports have described this situation in America and European countries, but a few have been published in Japan. In this study malignant pleural mesothelioma cases in hospitals located in an area facing the Seto Inland Sea were evaluated. A total of 106 patients were examined with 100 patients having had occupational exposure to asbestos and 6 patients without such histories of asbestos exposure. Ninety seven were male and 9 were female. Ages ranged from 41 to 87 yr with mean of 64.8+/-5.3 yr. Thirty seven cases showed epithelial type of tumor, 25 biphasic type and 15 showed sarcomatous. The remaining 23 cases had insufficient evidence for typing the tumor. The mean survival rate for all cases was 9.2+/-11.6 months. Fifty-one patients had occupational histories of shipyard work, 16 patients worked in asbestos cement piping, and the remainder were employed in miscellaneous jobs related asbestos exposure. The duration of asbestos exposure ranged up to 20 yr or longer with the mean of 17.2+/-8.9 yr and the average latent period for the occurrence of malignant pleural mesothelioma was more than 31 yr with the mean of 37.0+/-13.3 yr. Quantification of asbestos bodies in the lungs indicated a high concentration in most patients and the major types of asbestos fibers were crocidolite and amosite. Six cases appeared after exposure to chrysotile. These results indicated that ninety four percent of malignant pleural mesothelioma appeared due to the exposure to asbestos including crocidolite and amosite. The remainder may be blamed on exposure to chrysotile.     

Occupational characteristics of cases with asbestos-related diseases in The Netherlands

OBJECTIVE: To describe the occupational background of cases with an asbestos-related disease and to present overall mesothelioma risks across industries with historical exposure to asbestos. METHODS: For the period 1990-2000, cases were collected from records held by two law firms. Information on jobs held, previous employers, activities performed and specific products used were obtained from patients themselves or next of kin. Branches of industry and occupations were coded and the likelihood of asbestos exposure was assessed. For each branch of industry, the overall risk of mesothelioma was calculated from the ratio of the observed number of mesothelioma cases and the cumulative population-at-risk in the period 1947-1960. In order to compare mesothelioma risks across different industries, risk ratios were calculated for the primary asbestos industry and asbestos user industries relative to all other branches of industry. RESULTS: In total, 710 mesotheliomas and 86 asbestosis cases were available. The average latency period was approximately 40 yr and the average duration of exposure was 22 yr. Ship building and maintenance contributed the largest number of cases (27%), followed by the construction industry (14%), the insulation industry (12%), and the navy and army, primarily related to ship building and maintenance (5%). In the insulation industry, the overall risk of mesothelioma was 5 out of 100 workers, and in the ship building industry, 1 out of 100 workers. The construction industry had an overall risk comparable with many other asbestos-using industries (7 per 10,000 workers), but due to its size claimed many mesothelioma cases. CONCLUSION: The majority of cases with asbestos-related diseases had experienced their first asbestos exposure prior to 1960. For cases with first asbestos exposure after 1960, a shift was observed from the primary asbestos industry towards asbestos-using industries, such as construction, petroleum refining, and train building and maintenance. Due to the long latency period, asbestos exposure from 1960 to 1980 will cause a considerable number of mesothelioma cases in the next two decades.     

Trends in mortality from primary pleural tumor and incidence of pleural mesothelioma in Italy: a particularly serious situation

We present: a) an analysis of the past mortality from Primary Pleural Tumors (PPT) occurred in Italy between 1968 and 1992 by an age-cohort-period model, using a Poisson regression model, estimating the risk of dying by birth cohort, the Lifetime Cumulative risk (25-84 years) by birth cohort, the risk by calendar period and testing the full model (age-cohort-period effects); b) a summary of the incidence of mesothelioma as recorded in Italy by Cancer Registries and Mesothelioma Registries. The highest Lifetime Cumulative Risk of dying from TTP is recorded for the birth cohort 1946-'50 (6.2 per thousand among males, 1.64 among females). Whereas the risk by birth cohort becomes flat among females born after 1936, among males the risk is increasing up to the youngest birth cohorts. By calendar period, the highest risk of dying is observed in the last period (1991-'92). The inclusion in the full model of the calendar period term increases significantly the goodness-of-fit of the model among females, but not among males. The highest incidence of mesothelioma in both genders registered by 150 Cancer Registries all over the world is currently recorded among the population of Genoa and Trieste, where large ship-building plants are located. Even higher incidence mesothelioma rates have been recently recorded in other areas of Italy. The trend in PPT mortality in Italy could have been influenced, but not explained, by the increased awareness over time of the disease, but it fits well with the pattern occurring in most industrialized countries of western Europe, with the unprotected industrial use of asbestos which occurred in Italy, and also with the gender characteristics of the work-force employed in asbestos-exposing activities. A ban of asbestos use has been introduced in Italy in 1992. However, considering that asbestos seems to act as an initiator for mesothelioma, the trend in male mortality for PPT will not peak until two or three decades.     

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.     

Asbestos related diseases from environmental exposure to crocidolite in Da-yao,China. I. Review of exposure and epidemiological data

Background: Scattered patches of crocidolite, one form of asbestos, were found in the surface soil in the rural county of Da-yao in southwestern China. In 1983, researchers from the West China University of Medical Sciences (WCUMS) discovered that residents of two villages in Da-yao had hyperendemic pleural plaques and excessive numbers of pleural mesotheliomas.

Aims: To review and summarise epidemiological studies, along with other relevant data, and to discuss the potential contribution to environmental risk assessment.

Methods: This report is based on a review of several clinical/epidemiological studies conducted by WCUMS researchers since 1984, which included one cross sectional medical examination survey, one clinical/pathological analysis of 46 cases of mesothelioma, and three retrospective cohort mortality studies. Additional information acquired from reviewing original data first hand during a personal visit along with an interview of medical specialists from Da-yao County Hospital was also incorporated.

Results: The prevalence of pleural plaque was 20% among peasants in Da-yao over 40 years of age in the cross sectional survey. The average number of mesothelioma cases was 6.6 per year in the 1984–95 period and 22 per year in the 1996–99 period, in a population of 68 000. For those mesothelioma cases that were histology confirmed, there were 3.8 cases/year in the first period and 9 cases/year in the second. Of the 2175 peasants in this survey, 16 had asbestosis. Lung cancer deaths were significantly increased in all three cohort studies. The annual mortality rate for mesothelioma was 85 per million, 178 per million, and 365 per million for the three cohort studies, respectively. The higher exposed peasants had a fivefold increased mesothelioma mortality compared to their lower exposed counterparts. There were no cases of mesothelioma in the comparison groups where no crocidolite was known to exist in the environment. In the third cohort study, almost one of five cancer deaths (22%) was from mesothelioma. The ratio of lung cancer to mesothelioma deaths was low for all three studies (1.3, 3.0, and 1.2, respectively).

Conclusions: The observation of numerous mesothelioma cases at Da-yao was a unique finding, due mainly to their lifetime exposure to crocidolite asbestos. The finding of cases dying at a younger age and the relatively high ratio of mesothelioma cases to lung cancer could also be another unique result of lifetime environmental exposure to crocidolite asbestos. Although the commercial use of crocidolite has been officially banned since 1984, the incidence of mesothelioma has continued to show a steady increase, particularly among peasants. Since the latency of mesothelioma is approximately 30–40 years, the ban had little effect in the 1990s. The increased awareness and changes in diagnosis over time may also contribute to the increase. Furthermore, exposure to asbestos stoves and walls continued. The government implemented reduction of these exposures. However, from a public health standpoint, the most important issue is the complete avoidance of further exposure to asbestos.

     

Thirty-two cases of mesothelioma in Victoria, Australia: a retrospective survey related to occupational asbestos exposure.

Mesotheliomas have been reported in four states in Australia. Crocidolite has been mined and milled at Wittenoom in West Australia where five cases of mesothelioma were reported after exposure of high intensity. The 32 cases of mesothelioma reported in this paper occurred during a period of 11 years in Victoria; 29 were pleural and three peritoneal. There were 22 autopsies. End occupations were misleading in 66% of cases. Two of the three subjects with peritoneal mesothelioma were siblings, and there was no evidence of occupational or other exposure to asbestos in either. There was a significant prevalence of pulmonary asbestos bodies in the tumour series as compared with an unselected consecutive series of 200 routine autopsies (0.01 greater than P greater than 0.001). The occupational history was as effective a method of assessing 'true' asbestos exposure as the pulmonary asbestos body count. Five cases had had a duration of exposure of one year or less, but they had had heavy exposure. The latent interval before tumour development was 25 years or longer in each case. There was no known exposure to asbestos in five cases (16%). The rare association of mesothelioma with types of asbestos other than crocikolite may not exist and could be explicable on the basis of the proportion (16%) of these tumours arising randomly in the population.     

Mesothelioma in blood related subjects: report of 11 clusters among 1954 Italy cases and review of the literature

BACKGROUND: Malignant mesothelioma is a sporadic tumor related to asbestos. Its occurrence in blood relatives raises the question of potential contribution of predisposing factors. METHODS: The study analyses the features of mesothelioma in blood relatives that might explain the disease clustering. Data sources of familial clusters were three population-based Mesothelioma Registries in Italy (Veneto and Apulia Regions, Brescia province; 1978-2005) and Medline, Toxline, and Oshline/Hseline databases for a review of the literature (1968-2006). RESULTS: Eleven clusters (22 cases) were identified among 1954 Italy mesothelioma cases, and 51 clusters (120 cases) were extracted from 33 studies. The proportion of Italy familial cases was 1.4 per 100 mesothelioma cases; the ratio between the number of familial clusters and the number of non-familial mesothelioma cases was 1:148. The mesothelioma profile in consanguineous is the same as in non-consanguineous subjects (male prevalence; pleural site; age at diagnosis >50 years; asbestos exposure). Most clusters occurred in asbestos workers (shipyard, asbestos-cement production/processing, and insulation) and household-exposed blood relatives. Others were related to asbestos-cement factory pollution, asbestos-in-place, and handling asbestos-contaminated textiles. Two clusters were without any known exposure. Cancer family history revealed lung cancer cases in eight clusters. CONCLUSIONS: Available data support asbestos exposure as the main risk factor in mesothelioma cases among blood relatives. Our finding of a low proportion of familial cases would not suggest the influence of a large genetic component for mesothelioma in blood relatives.     

High incidence of mesothelioma in an English city without heavy industrial use of asbestos

BACKGROUND: Mesothelioma rates are increasing in the industrialized world, related to occupational asbestos exposure. The highest rates have been reported from areas with specific industries such as shipbuilding or mining. Lower rates have been reported from areas without such industries. We studied an area without heavy industry to examine if such a pattern occurred in England. METHODS: We studied the population of Exeter Primary Care Trust, Devon, United Kingdom, with a population of 131,849. Exeter has no mining, shipbuilding or other heavy industry. All lung cancers and mesotheliomas were identified from the local cancer registry, supplemented by searches at all primary care practices. The cancer diagnoses were checked by inspection of histology or primary care records. Occupational data were extracted from the primary care records. RESULTS: The searches revealed 291 lung cancers, 283 of which had either histological proof or strong clinical evidence for the diagnosis. Twenty-two (8 per cent) of these were pleural mesotheliomas, 17 of these occurring in men. The incidence rate of mesothelioma in men over 40 years was 12.1 per 100,000 per year (95 per cent confidence intervals 7.0-19.3), one of the highest reported rates in the world. CONCLUSION: The mesothelioma epidemic will extend to areas without local heavy industrial exposure.     

Mesothelioma associated with environmental exposures

BACKGROUND: The main sources of environmental, non-occupational exposure to asbestos or asbestiform fibres are: a) industrial plants in which asbestos was used in the production process; b) asbestos "in place" (mainly in buildings); c) contaminated soils. The association of these exposures with increasing risk of mesothelioma has been documented since 1960 in many places. OBJECTIVES AND METHODS: The present paper is aimed at describing the main results of studies performed in the locations with soils naturally contaminated with asbestos or asbestiform fibres. Environmental exposure data and asbestos-related health outcomes, mainly mesothelioma, are analyzed through a review of the literature. RESULTS: The sites with asbestos or other mesotheliomatogenous fibres in soils are characterized by low concentration levels of airborne fibres. Furthermore, exposure levels may increase when specific activities are carried out (mainly related to building construction), involving mechanical disturbance of fibre-containing materials. The type of fibres found are mainly amphiboles (tremolite). The population at risk of exposure is the general population, which can be exposed from birth. In these sites, the sex ratio of mesothelioma cases is close to 1.0 and the average age of cases ranges from 50 to 60 years. CONCLUSIONS: Both "natural"and industrial environmental asbestos or asbestiform fibre exposures increase potential risk for mesothelioma. Strategies of environmental reclamation and risk communication should be implemented in these areas.     

Thirty-two cases of mesothelioma in Victoria, Australia: a retrospective survey related to occupational asbestos exposure.

Mesotheliomas have been reported in four states in Australia. Crocidolite has been mined and milled at Wittenoom in West Australia where five cases of mesothelioma were reported after exposure of high intensity. The 32 cases of mesothelioma reported in this paper occurred during a period of 11 years in Victoria; 29 were pleural and three peritoneal. There were 22 autopsies. End occupations were misleading in 66% of cases. Two of the three subjects with peritoneal mesothelioma were siblings, and there was no evidence of occupational or other exposure to asbestos in either. There was a significant prevalence of pulmonary asbestos bodies in the tumour series as compared with an unselected consecutive series of 200 routine autopsies (0.01 greater than P greater than 0.001). The occupational history was as effective a method of assessing 'true' asbestos exposure as the pulmonary asbestos body count. Five cases had had a duration of exposure of one year or less, but they had had heavy exposure. The latent interval before tumour development was 25 years or longer in each case. There was no known exposure to asbestos in five cases (16%). The rare association of mesothelioma with types of asbestos other than crocikolite may not exist and could be explicable on the basis of the proportion (16%) of these tumours arising randomly in the population.