Colorectal cancer in asbestos cement workers in Denmark

Recent data on the risk of colorectal cancer following exposure to chrysotile are conflicting. We report on colorectal cancer morbidity in a large cohort of asbestos cement workers from Denmark mainly exposed to chrysotile. The total cohort had an SIR of 1.23 (95%CI 1.01–1.48). With a latency period of 15 years, men employed in the early (1928–1950) production period had an SIR of 1.47 (95%CI 1.05–2.01). With the observation of excess risks of colorectal cancer morbidity among chrysotile exposed asbestos cement workers in both Sweden and Denmark the question on the role of chrysotile in the etiology of colorectal cancer remains open. © 1996 Wiley-Liss. Inc.     

Commentary. Finnish Institute of Occupational Health Asbestos Program 1987–1992

In 1987–1992, the Finnish Institute of Occupational Health (FIOH) implemented a nationwide asbestos program aimed at preventing asbestos-related risks in good cooperation with governmental authorities, industry, trade unions, the health care and insurance systems, and mass media. The goals were to minimize all exposure to asbestos, identify people exposed at work, and improve the diagnostics of asbestos diseases, especially cancers. The program entailed several concrete actions and extensive dissemination of information, training, services, and scientific research. As proposed by the State Asbestos Committee, new use of asbestos products was banned and strict regulations were applied to renovation and inspection of old buildings. The screening study of asbestos-induced diseases included 18,943 current and retired workers from house building, shipyard, and asbestos industries. Pleural and parenchymal changes were found in 4.133 persons (22%), who were referred to further clinical examinations as suspected cases of an occupational disease. It was estimated that past exposure of asbestos among the Finnish population of 5 million causes > 150 mesotheliomas and lung cancers annually, totalling > 2,000 asbestos-induced cancer deaths by the year 2010. Although several major control actions were made or started during the program, the bulk of the preventive work still lies ahead.     

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.     

Retired and former asbestos workers in Hawaii

In 1979, a pilot survey defined respiratory status and unmet health care needs of retired and former male asbestos workers in Hawaii. Of 1,401 identified subjects, 741 were contacted and 411 were interviewed. Forty-five subjects were between 39 and 54 years of age; 208, between 55 and 64; and 158, age 65 or more. They represented the main ethnic groups--Caucasian, Chinese, Filipino, Hawaiian and part-Hawaiian, and Japanese--on Oahu. Most subjects had had significant exposure to asbestos in a shipyard, and 83% were current nonsmokers (160 had never smoked, and 111 were ex-smokers for ten years or more). Taking age and ethnicity into account, our group had more chronic respiratory and gastrointestinal problems than the comparable male population of Oahu in 1979, but fewer such problems than active shipyard workers elsewhere. These problems related primarily to current smoking status and secondarily to the length of asbestos exposure. Health care was available, but former workers used it less than retirees, despite having more symptoms. Very few abnormalities were reported by the subjects on their chest X-rays, pulmonary function tests, and sputum cytology performed elsewhere. These findings are compared to those of other shipyards, and support the hypothesis that the biological effects of asbestos exposure are generally mild in Hawaii.     

Cancer mortality and incidence of mesothelioma in a cohort of wives of asbestos workers in Casale Monferrato, Italy

BACKGROUND: Family members of asbestos workers are at increased risk of malignant mesothelioma (MM). Although the hazard is established, the magnitude of the risk is uncertain, and it is unclear whether risk is also increased for other cancers. Few cohort studies have been reported. OBJECTIVE: The "Eternit" factory of Casale Monferrato (Italy), active from 1907 to 1986, was among the most important Italian plants producing asbestos-cement (AC) goods. In this article we present updated results on mortality and MM incidence in the wives of workers at the factory. METHODS: We studied a cohort of 1,780 women, each married to an AC worker during his employment at the factory but not personally occupationally exposed to asbestos. Cohort membership was defined starting from the marital status of each worker, which was ascertained in 1988 from the Registrar's Office in the town where workers lived. At the end of follow-up (April 2003), 67% of women were alive, 32.3% dead, and 0.7% lost to follow-up. Duration of exposure was computed from the husband's period of employment. Latency was the interval from first exposure to the end of follow-up. RESULTS: The standardized mortality ratio (SMR) for pleural cancer [21 observed vs. 1.2 expected; SMR = 18.00; 95% confidence interval (CI), 11.14-27.52] was significantly increased. Mortality for lung cancer was not increased (12 observed vs. 10.3 expected; SMR = 1.17; 95% CI, 0.60-2.04). Eleven incident cases of pleural MM were observed (standardized incidence ratio = 25.19; 95% CI, 12.57-45.07). CONCLUSIONS: Household exposure, as experienced by these AC workers' wives, increases risk for pleural MM but not for lung cancer.     

Mortality study of asbestos cement workers

The present study describes cause-specific mortality of asbestos cement workers in the Emilia Romagna region of Italy. The cohort included workers in ten factories, most of which started operating between 1955 and 1965. Asbestos, mainly chrysotile, constituted 10%–20% of the dry component of the mixture. Crocidolite range between 5% and 50% of total asbestos. Asbestos concentrations up to 44 ff/cc were reported prior to 1975, while in recent years they have usually been below 0–1 ff/cc. The cohort included 3341 workers who had at some time been employed in the ten factories under study. Their mortality experience was compared with that of the population resident in Emilia Romagna. Vital status was ascertained at 1989. Seventy-three subjects were lost to followup (2.2%). Mortality from all causes and from all types of cancer was increased in the cohort. Malignant neoplasms of the respiratory tract showed a significant increase (SMR: 134; 90% confidence interval: 101–175; 40 observed) due to lung cancer (SMR: 124; 90% confidence interval: 91–166; 33 observed) and neoplasms of the pleura, mediastinum, and other parts of the respiratory tract (SMR: 602; 90% confidence interval 237–1267; 5 observed). The discrepancy between observed and expected mortality mainly concerned subjects with at least 20 years of employment in the factories. Five more cases of histologically confirmed mesothelioma occurred after the end of follow-up.     

Asbestos disease in sheet metal workers: the results of a proportional mortality analysis

The results of a proportional mortality analysis of a cohort of sheet metal workers who have only intermittent exposure to asbestos demonstrates a significant excess of cancer at the three sites most frequently associated with asbestos: lung, colon and rectum, and the mesothelium. No excess nonmalignant respiratory disease was detected. These data strongly suggest that significant asbestos-related disease is present in populations with secondary exposure to asbestos and emphasize the importance of considering possible asbestos-related disease when treating patients with a history of employment in the construction industry.     

Gastrointestinal cancer mortality of workers in occupations with high asbestos exposures

Asbestos, which is a well-known risk factor for lung cancer and malignant mesothelioma, has also been suggested as a gastrointestinal (GI) carcinogen. This study was conducted to assess the relationship between high asbestos exposure occupations and the occurrence of GI cancer. Death certificate data were analyzed from 4,943,566 decedents with information on occupation and industry from 28 states from 1979 through 1990. Elevated proportionate mortality ratios (PMRs) for mesothelioma were used to identify occupations potentially having many workers exposed to asbestos. All PMRs were age-adjusted and sex- and race-specific. The PMRs for GI cancers in white males were then calculated for these occupations after excluding mesothelioma, lung cancer, and non-malignant respiratory disease from all deaths. We identified 15,524 cases of GI cancer in the 12 occupations with elevated PMRs for mesothelioma. When these occupations were combined, the PMRs for esophageal, gastric, and colorectal cancer were significantly elevated at 108 (95% confidence interval = 107–110), 110 (106–113), and 109 (107–110), respectively. Esophageal cancer was elevated in sheet metal workers and mechanical workers. Gastric cancer was elevated in supervisors in production and managers. Colorectal cancer was elevated in mechanical and electrical and electronic engineers. However, high exposure occupations like insulation, construction painter supervisors, plumbers, furnace operators, and construction electricians showed no elevations of GI cancers. In conclusion, this death certificate study supports an association between asbestos exposure and some GI cancer, however the magnitude of this effect is very small. Am. J. Ind. Med. 31:713–718, 1997. © 1997 Wiley-Liss, Inc.     

Influence of age at death on accuracy of death certificate disease diagnosis: findings in 475 consecutive deaths of mesothelioma among asbestos insulation workers and asbestos factory workers.

Age at death had no appreciable influence on accuracy of death certificate diagnoses of 475 consecutive deaths of mesothelioma among asbestos insulation and asbestos factory workers, until age 75 or older.     

Cancer mortality among French Atomic Energy Commission workers

BACKGROUND: All causes and cancer mortality of 58,320 workers employed at the Commissariat à l'Energie Atomique (CEA) between 1946 and 1994 were compared with that of the general population in a retrospective cohort study. METHODS: Standardized Mortality Ratios (SMR) were computed with reference to the French national population. RESULTS: Between 1968 and 1994, 4,809 deaths occurred. A healthy worker effect is observed for men (SMR = 0.57, CI(90%) = [0.56;0.59]) and for women (SMR = 0.72, CI(90%) = [0.67;0.77]). Nine sites of cancer death were found to be in statistically significant deficit among men, none among women. An excess of pleural cancers is observed among men (SMR = 1.79, CI(90%) = [1.27;2.45]) and of malignant melanoma (SMR = 1.50, CI(90%) = [1.04;2.11]). An excess of breast cancer is observed among women on the borderline of significance (SMR = 1.14, CI(90%) = [0.94;1.37]). CONCLUSIONS: Excesses observed will have to be related to occupational exposures in the on-going cohort study on French nuclear workers which includes a retrospective exposures assessment.     

Occupational asbestos exposure and predictable asbestos-related diseases in India

BACKGROUND: India imports nearly 100,000 metric tons of asbestos per year, and small-scale asbestos (chrysotile and tremolite) mining and milling contributes nearly 5%-10% of the total national usage. The industry is relatively young, having started in the 1950s and 1960s. METHODS: Surveys of asbestos-exposed workers have identified significant occupational exposures, early pleural and parenchymal changes on chest radiograph, and decrements in lung function. RESULTS AND CONCLUSIONS: Based on knowledge of past and current exposures to asbestos in industry, we can predict a future occurrence of clinical asbestos-related diseases-pleural changes, pulmonary fibrosis, bronchogenic carcinoma, and diffuse malignant mesothelioma. These cases of asbestos related disease are expected to occur in asbestos exposed workers from mining, milling, and manufacturing as well as in those with secondary exposures to asbestos-containing materials, including construction and maintenance workers, users of asbestos-containing consumer products, and the occupants of asbestos-containing buildings.     

Mortality of workers at a nuclear materials production plant at Oak Ridge,Tennessee, 1947–1990

The Y-12 plant at Oak Ridge, Tennessee, produced nuclear materials for the U.S. government's nuclear weapons program beginning in 1943. Workers at Y-12 were exposed to low dose, internal, alpha radiation and external, penetrating radiation, as well as to beryllium, mercury, solvents, and other industrial agents. This paper presents updated results from a long-term mortality study of workers at Y-12 between 1947 and 1974, with follow-up of white men through 1990 and data reported for the first time for women and men of other races. Vital status was determined through searches of the National Death Index and other records, and the workers' mortality was compared to the national population's using standardized mortality ratios (SMRs). Total mortality was low for all Y-12 workers and total cancer mortality was as expected. Among the 6,591 white men, there were 20% more lung cancer deaths than expected (95% confidence interval /CI/ 1.04–1.38). Death rates from brain cancer and several lymphopoietic system cancers were also elevated among white men, with SMRs of 1.28 and 1.46. Mortality from cancer of the pancreas, prostate, and kidney was similarly elevated. There was evidence of excess breast cancer among the 1,073 female workers (SMR 1.21, 95% CI 0.60–2.17). Lung cancer mortality among these workers warrants continued surveillance because of the link between internal alpha radiation exposure and this disease, but other agents, notably beryllium, also merit consideration as potential causes of lung cancer. Other cancers and agents should also be investigated as part of a comprehensive study of the health consequences of the production of nuclear weapons. © 1996 Wiley-Liss, Inc.     

Mortality of Carpenters' Union members employed in the U.S. construction or wood products industries, 1987–1990

This study evaluated the mortality of 27,362 members of the U.S. Carpenters' Union who died 1987–1990. Age-adjusted proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were computed using the U.S. age-, gender-, and race-specific proportional mortality for the years of the study. For white male carpenters who were last employed while in construction industry locals, raised mortality was observed for lung cancer (PCMR = 107, CI = 103, 111), bone cancer (PCMR = 181, CI = 107, 286), asbestosis (PMR = 283, CI = 158, 457), emphysema (PMR = 115, CI = 102, 130), transportation injuries (PMR = 121, CI = 109, 135), and falls (PMR = 122, CI = 104, 142). For white male carpenters who were last employed while in industrial wood products locals, significantly raised mortality occurred for stomach cancer (PCMR = 187, CI = 136, 250), male breast cancer (PCMR = 469, CI = 128, 720), and transportation injuries (PMR = 136, CI = 110, 173). Excess breast cancer was associated with last employment in wood machining trades. Nasal cancer mortality was not elevated. A total of 121 mesotheliomas were observed. Contributing cause of death analyses revealed raised mortality for these and additional causes; 4,594 (18%) death certificates mentioned occupational and other lung disease as a contributing factor, resulting in significantly elevated mortality. These data show that construction carpenters have moderately elevated mortality for the diseases caused by asbestos (lung cancer and malignant mesothelioma) and from traumatic injuries. The finding of elevated mortality for stomach, bone, and breast cancer was unexpected and requires further evaluation of possible occupational factors. This study confirms that construction carpentry is an extremely hazardous trade. The data suggest that additional preventive action guarding against asbestos exposure and occupational injury is urgently needed in this occupation. (This is a US Government work, and, as such, is in the public domain in the United States of America.) © 1996 Wiley-Liss. Inc.     

A historical cohort mortality study among shipyard workers in Genoa, Italy

BACKGROUND: A historical cohort mortality study was conducted among 3984 shipyard workers assigned to ship repair, refitting, and construction in the harbor of Genoa, Italy, between 1960 and 1981. These workers were exposed to asbestos fibers, welding fumes and gases, silica dust, polycyclic aromatic hydrocarbons, and solvents. METHODS: Workers were classified in 20 different job-titles depending upon the type of activity. Standardized mortality ratios (SMRs) were computed using male residents of the Province of Genoa as the referent population. RESULTS AND CONCLUSIONS: For the whole cohort significantly increased SMRs were detected for all causes, all cancers, liver, larynx, lung, pleural and bladder cancers, respiratory tract diseases, and cirrhosis of the liver. The analysis by job-title showed increased SMRs not only for pleural cancer, but also for lung, laryngeal cancers and respiratory tract diseases in occupations entailing heavy asbestos exposure. Bladder and liver cancers and liver cirrhosis mortality also appeared to be related to occupational exposure.     

Analysis of asbestos bodies in BAL from subjects with particular exposures

Four patients with asbestos-related diseases and with unusual exposures underwent bronchoalveolar lavage (BAL) for mineralogical analysis. Asbestos bodies (AB) were counted by light microscopy and analyzed by transmission electron microscopy and X-ray energy spectrometry. AB's were found in all cases, after a mean delay from the end of exposure of 27.7 years. Analysis of the core fibers indicated the type of alveolar asbestos burden and was compared with the previous exposures: —Pleural plaques due to household exposure to amosite and crocidolite. —Pleural plaques due to occult occupational exposure to crocidolite in a coal miner. —Asbestosis due to environmental exposure to tremolite in Turkey. —Asbestosis, pleural plaques, and peritoneal mesothelioma due to a short, intense exposure to crocidolite. AB counting in BAL and identification of the central fibers by analytical electron microscopy is a useful, non-invasive and reliable method to evaluate the alveolar retention of bio-persistent fibers and to relate them to specific exposures. Am. J. Ind. Med. 31:699–704, 1997. © 1997 Wiley-Liss, Inc.