Sinonasal cancer and furniture workers: update and methodological points

Using data drawn and adapted from the 1980 national census and the mortality statistics for the years 1979-1985, we update our previously published standardized mortality ratio for sinonasal cancer mortality and odds ratio for sinonasal adenocarcinoma death among Swiss furniture workers. The former is 620 (95% confidence interval 360-1020, p less than 0.00001), the latter is 75.     

Historical cohort study of US man-made vitreous fiber production workers: II. Mortality from mesothelioma

As part of our ongoing mortality surveillance program for the US man-made vitreous fiber (MMVF) industry, we examined mortality from malignant mesothelioma using data from our 1989 follow-up of 3478 rock/slag wool workers and our 1992 follow-up of 32,110 fiberglass workers. A manual search of death certificates for 1011 rock/slag wool workers and 9060 fiberglass workers revealed only 10 death certificates with any mention of the word "mesothelioma." A subsequent review of medical records and pathology specimens for 3 of the 10 workers deemed two deaths as definitely not due to mesothelioma and one as having a 50% chance of being caused by mesothelioma. Two other deaths, for which only medical records were available, were given less than a 50% chance of being due to mesothelioma. Eight of the 10 decedents had potential occupational asbestos exposure inside or outside the MMVF industry. We also estimated the mortality risk from malignant mesothelioma in the cohort using two cause-of-death categorizations that included both malignant and benign coding rubrics. Using the more comprehensive scheme, we observed overall deficits in deaths among the total cohort and fiberglass workers and an overall excess among rock/slag wool workers. The excess in respiratory system cancer is largely a reflection of elevated lung cancer risks that we attributed mainly to confounding by smoking, to exposures outside the MMVF industry to agents such as asbestos, or to one or more of the several co-exposures present in many of the study plants (including asbestos). The second scheme, which focused on pleural mesothelioma in time periods when specific malignant mesothelioma coding rubrics were available, classified only one cohort death as being caused by malignant mesothelioma, compared with 2.19 expected deaths (local county comparison). We conclude that the overall mortality risk from malignant mesothelioma does not seem to be elevated in the US MMVF cohort.     

Mortality of workers at two asbestos-cement plants in Poland

To assess mortality rate among workers occupationally exposed to asbestos, cohort studies were carried out in two asbestos cement plants operating since the 1960s. Asbestos cement sheets for roofing and siding have been manufactured there, using mostly chrisotile, and since 1985 also crocidolite for pressure pipes. In all, the cohort comprised 3,220 workers, including 2,616 male workers. Subject to consideration were the workers employed for at least three months in the period between the onset of the production and 1980. The vital status of the subjects was traced up to 31 December 1991. The availability of the cohort was 96.8%. Workers' mortality was analysed using standardized mortality ratio (SMR). The reference group was the general population of Poland. In the male cohort, 385 cases of death were recorded. Statistically significant excess of mortality from large intestine cancer (7 cases, SMR = 264) and pleural mesothelioma (5 cases, SMR = 2846) was found. In male workers who died from pleural mesothelioma the work history ranged from 12 to 26 years. An excess mortality from pleural mesothelioma was also noted among the female workers (2 cases, SMR = 11,275). No malignant neoplasms of other locations produced significant excess mortality either in the male or female workers.     

A proportional study of cancer registrations of dockyard workers.

Evidence of an occupational effect due to asbestos exposure was sought by comparing cancer registrations for dockyard workers with those for Plymouth men in the same age groups for 1960-69. The results show a significant excess of pleural tumours in the dockyard group but no significant excesses at other sites. Registrations for pleural mesothelioma were recorded for men with many dockyard occupations and the observed mean interval between first exposure to asbestos and registration for a pleural tumour (37.6 years) indicates that cases of pleural mesothelioma may be expected to occur among these workers for many years, even though crocidolite is no longer used in naval ships. A trend of increasing annual excess of stomach and gastrointestinal registrations was observed in the dockyard group. No cases of peritoneal mesothelioma were recorded but it is likely that some did occur which were diagnosed as cancers arising from other sites. This may account for some of the excess of gastrointestinal registrations.     

A proportional study of cancer registrations of dockyard workers.

Evidence of an occupational effect due to asbestos exposure was sought by comparing cancer registrations for dockyard workers with those for Plymouth men in the same age groups for 1960-69. The results show a significant excess of pleural tumours in the dockyard group but no significant excesses at other sites. Registrations for pleural mesothelioma were recorded for men with many dockyard occupations and the observed mean interval between first exposure to asbestos and registration for a pleural tumour (37.6 years) indicates that cases of pleural mesothelioma may be expected to occur among these workers for many years, even though crocidolite is no longer used in naval ships. A trend of increasing annual excess of stomach and gastrointestinal registrations was observed in the dockyard group. No cases of peritoneal mesothelioma were recorded but it is likely that some did occur which were diagnosed as cancers arising from other sites. This may account for some of the excess of gastrointestinal registrations.     

Three decades of pleural cancer and mesothelioma registration in Austria where asbestos cement was invented

Recently, a new mesothelioma epidemic was predicted from observations made in Western Europe. From early observations in Austria the lower increase in cases of mesothelioma compared with neighbor countries had been related to different uses of asbestos. In order to test this hypothesis, incidence and mortality of pleural cancer [International Classification of Diseases (ICD)-8/9 163] were analyzed for three decades and supplemented by data from a cohort study in the factory that had been the largest consumer of asbestos imported to Austria and from all Austrian occupational diseases registered between 1990 and 2001. In men, mortality rates (based on 15 to 45 deaths/year) were lowest in 1980-1989, but similar in 1970-1979 and 1990-2001. No increase in younger-birth cohorts was detected. Incidence rates (based on 13 to 44 cases/year) increased (36%) non-significantly ( P=0.14). In women, a significant decrease in mortality and incidence rates ( P<0.01) was observed from 1970. Rates from work-related mesothelioma (based on only 0-7 men and 0-4 women/year) must be interpreted with caution. In the cohort of 2,816 asbestos cement workers 26 pleural mesotheliomas were registered from 1990 through mid-1999. Six of these cases (three male and three female) had not been registered as an occupational disease, but all of these cases had been encoded under ICD 163 in mortality statistics. One female cohort member registered as having asbestosis according to the death certificate had died from mesothelioma according to the statistics of occupational diseases. We conclude that no epidemic of mesothelioma due to past asbestos exposure is to be expected in Austria.     

Mortality of asbestos workers in England and Wales 1971-81.

A national study of British asbestos workers is briefly described and the mortality experience of 31 150 male asbestos workers in England and Wales who had been medically examined at least once as part of that survey is presented. The survey population is divided into workers with occupational exposure to asbestos before the inception of the 1969 Asbestos Regulations and those who worked with asbestos only after 1969. Of the 1128 who had died, 897 had worked before 1969; 34 of the death certificates received for these men mentioned mesothelioma and for another nine asbestosis was reported in the absence of mesothelioma or lung cancer. A statistically significant excess of lung cancer (SMR 136) was found. For the post-1969 workers, one case of asbestosis and one case of mesothelioma were reported, but further investigation of these cases showed probable occupational exposure to asbestos many years before 1969. The time from first exposure for this section of the population is too short to exclude an excess of asbestos related disease. The most noticeable excess of asbestos related disease was seen among the insulation workers who had more than twice (SMR 256) the expected number of deaths from lung cancer, and for whom almost 10% of all death certificates mentioned mesothelioma. No excess of any alimentary tract cancer was found and the population showed a significant deficit of large bowel cancer mortality (SMR 54).     

Mortality of asbestos workers in England and Wales 1971-81

A national study of British asbestos workers is briefly described and the mortality experience of 31 150 male asbestos workers in England and Wales who had been medically examined at least once as part of that survey is presented. The survey population is divided into workers with occupational exposure to asbestos before the inception of the 1969 Asbestos Regulations and those who worked with asbestos only after 1969. Of the 1128 who had died, 897 had worked before 1969; 34 of the death certificates received for these men mentioned mesothelioma and for another nine asbestosis was reported in the absence of mesothelioma or lung cancer. A statistically significant excess of lung cancer (SMR 136) was found. For the post-1969 workers, one case of asbestosis and one case of mesothelioma were reported, but further investigation of these cases showed probable occupational exposure to asbestos many years before 1969. The time from first exposure for this section of the population is too short to exclude an excess of asbestos related disease. The most noticeable excess of asbestos related disease was seen among the insulation workers who had more than twice (SMR 256) the expected number of deaths from lung cancer, and for whom almost 10% of all death certificates mentioned mesothelioma. No excess of any alimentary tract cancer was found and the population showed a significant deficit of large bowel cancer mortality (SMR 54).     

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.     

A mortality study among workers in an English asbestos factory.

The previous report on this cohort study of workers in an asbestos textile factory (Knox et al., 1968) showed little evidence of increased mortality among workers who had entered the factory after the implementation in 1932 of the first Asbestos Industry Regulation (1931) but observed that no firm conclusions could be drawn, as little carcinogenic effect would be expected for 20 years after first exposure. A further 8 1/2 years of follow-up has revealed some asbestos-related disease in this latter group, although very much less than for employees first exposed before 1933. Among the 963 workers first exposed in 1933 or later, mortality was increased for carcinoma of the bronchus (31 deaths; 19-3 expected for all lung cancers) and non-malignant respiratory disease (35 deaths, 25-0 expected), and a further 5 deaths were attributed to pleural mesothelioma.     

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.     

Regional differences in the compensation of pleural mesothelioma as occupational disease in France (1986-1993)

BACKGROUND: Occupational exposure to asbestos is responsible for 80% at least of all mesothelioma in developed countries. In France there are important regional differences in the rate of mesothelioma compensated as occupational diseases, without knowing if these differences could be explained by a real difference of risk. The objective here is to quantify these regional differences in relation with the differences of level of risk. METHODS: The analysis compares, for each of the 16 regions of the national social security system, mortality for both genders and among men by pleural cancer (ICD 163) in the general population and mesothelioma compensated as occupational diseases during the 1986-1993 period. We computed for each region the number of expected compensated mesothelioma under the hypothesis where the regional distributions of compensated mesothelioma and mesothelioma deaths are the same; as well as the percentage of compensated mesothelioma compared to the deaths, and the variation from the national mean under two hypotheses, high and low; and the probability that a mesothelioma is compensated as an occupational disease taking as a reference the "best" region. RESULTS: The compensation rate differed significantly among regions (p < 0.05) and for men, the rate between observed and expected numbers of compensated mesothelioma varied from 0.15 (region of Montpellier) to 2.29 (region of Nantes), a ratio over 15. For all of France, the compensation rate was 25% under the best hypothesis. The region of Nantes compensated 61.5% of the male mesothelioma as occupational diseases, while the region of Montpellier and Clermont-Ferrand only around 5%. The probability for a mesothelioma to be compensated, compared to the region of Nantes, was 2.5 times less in national average, and about 10 times less in Montpellier and Clermont-Ferrand regions. CONCLUSION: In spite of limits linked to the imprecision of the available data, important regional differences in term of compensation of mesothelioma as occupational diseases clearly exist. Indications lead to think that their origin lies essentially in differences between physicians when considering the occupational etiology of mesothelioma, but differences within the system of compensation of occupational diseases can not be excluded. An improvement of the national statistical system concerning occupational diseases is highly recommendable.     

Epidemiological investigation on the health status of employees in two factories manufacturing and repairing railway rolling stock: a historical perspective study of mortality

BACKGROUND: Epidemiological studies of cancer risk due to occupational exposure to asbestos in production and repair of railway rolling stock has so far given consistent results for mesothelioma, but conflicting evidence for lung cancer. OBJECTIVES: The main purpose of this study was to investigate risk for mesothelioma and lung cancer in relation to estimated patterns of exposure in the occupational environment of railway rolling stock manufacture and repair. METHODS: A historical prospective study approach was adopted. The mortality experience of the study population was compared to that of the population of the Veneto Region. Two historical cohorts of workers employed in two plants manufacturing and repairing railway coaches were followed up for mortality. A total of 1,621 workers were enrolled in the study from the first factory, and 1,190 from the second. RESULTS: An elevation of both pleural mesothelioma and lung cancer was reported in the two factories with SMRs of 21.52 (CI 95%=1.64-32.29) and 6.46 (CI 95%=1.33-18.88), and 1.26 (CI 95%=1.01-1.54) and 1.18 (CI 95%=0.81-1.66) respectively. The two excesses however showed different patterns in relation to historical exposure estimates, which appear to correlate with mesotheliomas but not with lung cancer. An elevation of mortality for non-neoplastic respiratory diseases was associated with employment during periods when it was estimated that exposure was at higher levels in one of the two firms. CONCLUSIONS: The results confirm the high carcinogenic risk deriving from asbestos exposure, although inconsistencies were found between target organs in relation to exposure estimates, and the existence of time periods in production in which cancer risk was different.     

Pleural mesothelioma: A descriptive analysis based on a case-control study and mortality data in Ile de France, 1987–1990

Incidence rates of pleural mesothelioma in Ile de France were examined for the period 1987–1990, on the basis of information collected in a case-control study. This study was designed to include all new cases of pleural mesothelioma occurring in the region. On the other hand, mortality rates from pleural malignancies in the same region were examined on the basis of death certificates recorded by INSERM for the same period. A large difference was found between the two types of data. Average annual incidence rates were 7.5 per million among men and 1.6 per million among women. Average annual mortality rates due to primary pleural malignancies were 25.2 per million in males and 8.9 per million in females. This study confirms discordances between incidence and mortality data for pleural malignancies already reported in several countries. However, contrasting with some previous reports, the annual mortality rate from pleural malignancies was higher than the incidence rate of mesothelioma in this study. This emphasizes the usefulness of a specific investigation to explain such discordances, prior to comparison of data from one country to another.     

Survival of asbestos insulation workers with mesothelioma.

Malignant mesothelioma is a lethal disease. It is rare in the general population; however, workers exposed to asbestos suffer significant burdens of the neoplasm. The survival time of 457 consecutive fatal cases of pleural and peritoneal mesothelioma that occurred among 17,800 asbestos insulation workers observed prospectively from 1 January 1967 to 1 January 1987 was studied. Mean survival time from initial presentation of the disease to death was 11.4 months for the pleural mesothelioma patients compared with 7.4 months for the peritoneal group. This difference was statistically significant. Mean survival time from diagnosis to death was shorter for both groups of patients: 8.4 months for pleural mesothelioma v 5.8 months for the peritoneal cases. In conclusion, survival time in mesothelioma patients is short; most die within a year from the onset of the initial symptoms. No effective therapy is yet available.     

Mortality among three refinery/petrochemical plant cohorts. II. Retirees

This study updates mortality data for 6238 retirees from three refinery/petrochemical plants. Almost 90% of the cohort was deceased. Deaths from all causes (standardized mortality ratio, 104; 95% confidence interval, 102 to 107) and all cancers (standardized mortality ratio, 109; 95% confidence interval, 102 to 116) were elevated. Increased deaths due to kidney cancer, mesothelioma, and the category of other lymphohemopoietic cancers also were observed. The rate of leukemia was not increased. There was little internal or external consistency to support an occupational relationship for kidney cancer, but findings for mesothelioma and other lymphohemopoietic cancers are consistent with reports for other petroleum cohorts. Analyses by age indicated significantly higher all-cause mortality rates among persons retiring before age 65. The results suggest that continued surveillance of mesothelioma and lymphohemopoietic cancer malignancies in younger workers with more contemporary exposures may be warranted. Furthermore, age at retirement should be considered when analyzing occupational cohorts.     

Relationship of mortality, occupation, and pulmonary diffusing capacity to pleural thickening in the First National Health and Nutrition Examination Survey

We studied the relationship of pleural thickening consistent with asbestos exposure to mortality, career employment in asbestos-related jobs, and pulmonary diffusing capacity among participants in the first National Health and Nutrition Examination Survey. Three "B" readers examined chest X-rays to identify 59 individuals with such pleural abnormalities. From 1975 to 1984, the all-cause mortality rate ratio (RR) comparing males with and without occupational pleural thickening was 1.3 (95% C.I. 0.8-2.2). For lung cancer, the mortality RR for males was 3.0 (95% C.I. 1.0-9.1). Career asbestos work was not associated with occupational pleural thickening among men, probably because some with the condition had only short-term exposure to asbestos. Pulmonary diffusing capacity was lower in those with occupational pleural thickening, taking smoking into account. These results suggest that individuals in the general population who have occupational pleural thickening are at risk for some of the health consequences of asbestos work, including lung cancer, even if they were not career asbestos workers.     

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.     

SWORD '97: surveillance of work-related and occupational respiratory disease in the UK

SWORD is one of seven clinically based reporting schemes which together now provide almost comprehensive coverage of occupational diseases across the UK. Although SWORD is now in its tenth year, participation rates remain high. Of an estimated 3,903 new cases seen this year, 1,031 (26%) were of occupational asthma, 978 (25%) of mesothelioma, 794 (20%) of non-malignant pleural disease, 336 (9%) of pneumoconiosis and 233 (6%) of inhalation accidents. Incidence rates of occupational asthma were generally highest among workers in the manufacture of wood products, textiles and food (particularly grain products and crustaceans) and additionally, in the production of precious and non-ferrous metals, rubber goods, detergents and perfumes, and in mining. Health care workers were noted to have a surprisingly high incidence of inhalation accidents. Occupational asthma attributed to latex has increased dramatically; the highest rates are among laboratory technicians, shoe workers and health care workers.     

Malignant mesothelioma in a cohort of asbestos insulation workers: clinical presentation, diagnosis, and causes of death.

Malignant mesothelioma has been rare in the general population. In recent decades its incidence has risen dramatically, parallel to the increasing use of asbestos in industry since 1930. Altogether 17,800 asbestos insulation workers, members of the International Association of Heat and Frost Insulators and Asbestos Workers (AFL-CIO-CLC) in the United States and Canada, were enrolled for prospective study on 1 January 1967 and followed up to the present. Every death that occurs is investigated by our laboratory. One hundred and seventy five deaths from mesothelioma occurred among the 2221 men who died in 1967-76 and 181 more such deaths in the next eight years. Altogether, 356 workers had died of malignant mesothelioma (pleural or peritoneal) by 1984. Diagnosis of mesothelioma was accepted only after all available clinical, radiological, and pathological material was reviewed by our laboratory and histopathological confirmation by the pathology unit made in each case. One hundred and thirty four workers died of pleural and 222 of peritoneal mesothelioma. Age at onset of exposure, age at onset of the disease, and age at death were similar in both groups of patients. Significant difference was noted only in the time elapsed from onset of exposure to the development of first symptoms, which was longer in the group with peritoneal mesothelioma. Shortness of breath, either new or recently increased, and chest pain were the most frequent presenting symptoms in the group with pleural mesothelioma; abdominal pain and distension were frequent in the patients with peritoneal mesothelioma. Pleural effusion or ascites were found in most patients. The most effective approach to the diagnosis of malignant pleural mesothelioma in these cases was by open lung biopsy; exploratory laparotomy was best for diagnosing peritoneal mesothelioma. Patients with pleural mesothelioma died principally from pulmonary insufficiency whereas those with peritoneal mesothelioma succumbed after a period of pronounced wasting.