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Query: UMLS:C0037116 (silicosis)
 1,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of crystalline silica in lung cancer has long been the subject of controversy. In this article, we review the main experimental and epidemiological studies dealing with this problem. Some evidence for a genotoxic potential of crystalline silica has been obtained in the rare in vitro studies published to date. In vivo studies have shown that crystalline silica is carcinogenic in the rat; the tumour types appear to vary according to the route of administration. In addition, an association between carcinogenic and fibrogenic potency has been observed in various animal species exposed to crystalline silica. An excess of lung cancer related to occupational exposure to crystalline silica is reported in many epidemiological studies, regardless of the presence of silicosis. However, most of these studies are difficult to interpret because they do not correctly take into account associated carcinogens such as tobacco smoke and other occupational carcinogens. An excess of lung cancer is generally reported in studies based on silicosis registers. Overall, experimental and human studies suggest an association between exposure to crystalline silica and an excess of pulmonary malignancies. Although the data available are not sufficient to establish a clear-cut causal relationship in humans, an association between the onset of pneumoconiosis and pulmonary malignancies is probable. In contrast, experimental observations have given rise to a pathophysiological mechanism that might account for a putative carcinogenic potency of crystalline silica.
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PMID:Silica and lung cancer: a controversial issue. 165 12

Since 1940, 760 cases of silicosis have been diagnosed as part of the State of North Carolina's (NC) pneumoconiosis surveillance program for dusty trades workers. Vital status was ascertained through 1983 for 714 cases that had been diagnosed since 1940 and death certificates were obtained for 546 of the 550 deceased. Mortality from tuberculosis, cancer of the intestine and lung, pneumonia, bronchitis, emphysema, asthma, pneumoconiosis, and kidney disease was significantly increased in whites. Mortality from tuberculosis, ischemic heart disease, and pneumoconiosis was significantly increased in non-whites. The standardized mortality ratio (95% CI) for lung cancer based on U.S. rates was 2.6 (1.8-3.6) in whites, 2.3 (1.5-3.4) in those who had no exposure to other known occupational carcinogens, and 2.4 (1.5-3.6) in those who had no other exposure and who had been diagnosed for silicosis while employed in the NC dusty trades. Age-adjusted lung cancer rates in silicotics who had no exposure to other known occupational carcinogens were 1.5 (.8-2.9) times higher than that in a referent group of coal miners with coalworkers' pneumoconiosis (CWP) and 2.4 (1.5-3.9) times higher than that in a referent group of non-silicotic metal miners. Age- and smoking-adjusted rates in silicotics were 3.9 (2.4-6.4) times higher than that in metal miners. This analysis effectively controls for confounding by age, cigarette smoking, and exposure to other known occupational carcinogens, and it is unlikely that other correlates of silica exposure could explain the excess lung cancer mortality in the silicotics.
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PMID:Silicosis and lung cancer in North Carolina dusty trades workers. 186 18

Cancer incidence was studied among 6,144 male foundry workers who were invited to participate in either of two Danish national silicosis surveys conducted during 1967-1969 and 1972-1974. Cancer incidence was followed through to the end of 1985 by computerized linkage to the Danish Cancer Registry, and Standardized Morbidity Ratios (SMRs) were calculated based on incidence rates for the Danish population. For the entire cohort, significantly elevated SMRs were seen for all cancers (SMR, 1.09; 95% CI, 1.01-1.18) and lung cancer (SMR, 1.30; 95% CI, 1.12-1.51), and SMRs were at the borderline of statistical significance for bladder cancer (SMR, 1.24; 95% CI, 0.97-1.59). Excess lung and bladder cancer risk were confined to workers who had worked in foundries for at least 20 y. There was a positive correlation between silicosis prevalence in employees at the foundries at the time of the x-ray examinations and lung cancer incidence during the follow-up period. Squamous cell carcinomas, anaplastic carcinomas, and other lung cancers accounted for the excess lung cancer risk, whereas there was not excess risk among the foundry workers for adenocarcinomas of the lung.
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PMID:Cancer incidence among foundry workers in Denmark. 200 97

The International Agency for Research in Cancer (IARC) has recently stated that crystalline silica should be regarded as a potential carcinogen. The IARC bases this statement on a finding that there is limited evidence of carcinogenicity in humans and sufficient evidence for carcinogenicity in animals. Recent laboratory animal experiments demonstrating a carcinogenic response to silica exposure have intensified scientific and regulatory concern for crystalline silica as a respiratory carcinogen. Studies of human populations have been contradictory in demonstrating a causal relationship between crystalline silica exposure and lung cancer. This paper reviews recent experimental evidence and attempts to identify the gaps and inconsistencies in our understanding of the relationship between exposure to crystalline silica and the two diseases of concern: silicosis and pulmonary neoplasia. Given our current level of understanding and the need for more scientific data it seems premature to initiate changes in exposure regulations at this time.
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PMID:Crystalline silica and lung cancer: a review of recent experimental evidence. 207 59

The quartz content of ordinary building materials such as concrete, mortar and bricks is 10-50%. The extension of concrete building which has occurred since 1960 and the subsequent repairs and preparation by means of mechanical tools result in increased concentrations of dust containing quartz. Measurements at various types of work in Danish building sites reveal that the quantity of respirable quartz constitutes 0.16-1.8 mg/m3 (limit 0.1 mg/m3). Corresponding figures are found in investigations from abroad. Cases of silicosis have been reported among builders abroad and, in Denmark, only few cases of occupational dust lung conditions have been notified to the Workers' Supervision Authorities. Whether or not quartz in dust at building sites also causes an increase in the occurrence of cancer of the lung, as is the case in sandstone workers exposed to pure quartz, has not yet been proved. The latent period of several decades for the development of silicosis is such that it may well be feared that the cases now reported are only the beginning of increased occurrence of the disease in coming years among particularly exposed concrete workers, bricklayers, unskilled workers, electricians, joiners and carpenters. Relevant technical methods have already been developed to limit exposure to quartz-containing dust at building sites. Prophylactic measures should be accelerated.
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PMID:[The risk of silicosis from building site dust]. 216 55

Two patients of ataxic sensory neuropathy associated with silicosis were studied. Case 1 is a 53-year-old (in 1979) man who was a stonecutter for 40 years and diagnosed as silicosis in 1973. Case 2 is a 64-year-old (in 1984) man who was a glasscutter for 30 years and had been treated for silicosis from 1980 to 1982. Both patients developed dysesthesias in the hands, feet and face asymmetrically and gait ataxia over a few months. Vibratory and joint position senses were profoundly diminished but were accompanied by only mildly decreased pain and temperature sensations. Their muscle power was almost unchanged. Both had absent muscle power was almost unchanged. Both had absent muscle stretch reflexes. Sensory nerve conduction velocities were absent and motor nerve studies were almost normal. Nerve biopsy in case 2 showed a severe loss of large myelinaed fibers, and no inflammatory infiltrates and onion bulb formations. Although these findings suggested the carcinomatous neuropathy, we could not find any malignancy. Both patients had elevated polyclonal gamma-globulin levels and rheumatoid factors and, in case 2 an increase of IgG in serum. Cerebrospinal fluid showed an albumino-cytogenic dissociation and steroid therapy was successful in both patients. Case 1 died of pneumonia in 1989. Though an autopsy was not performed, his condition had continued to improve without signs of malignancy during 10 years. The condition of case 2 has also continued to improve, although ataxias remain.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Two cases of ataxic sensory neuropathy associated with silicosis]. 217 42

The results of two epidemiologic investigations on dust-related lung diseases are presented. The two studies had different aims and designs. A cross-sectional study was done to investigate the silicosis prevalence in Dutch fine ceramic workers. In the small ceramic workshops in the Gouda region, simple pneumoconiosis is still commonly present (13.3%), whereas the silicosis prevalence in the highly mechanized industries is low (1.7%). Furthermore, heavy smoking seems to enhance the risk for silicosis after long-term exposure to quartz. A case-control study was performed to analyze the relation between dust exposure in the fine ceramic and coal mining industries and lung cancer. No relation between a work history in the dusty trades and lung cancer emerged, and a correlation with a specific histologic tumor cell type could not be demonstrated. Apparently, workers in the Dutch fine ceramic or coal mining industry have no increased risk of developing lung malignancies.
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PMID:Epidemiologic studies of inorganic dust-related lung diseases in The Netherlands. 230 46

Cancer incidence and cause-specific mortality were studied in a male cohort of 94 talc miners and 295 talc millers, exposed to non-asbestiform talc with low quartz content. No excess risk was found compared with national age-specific incidence. Six cases of lung cancer occurred versus 6.49 expected (miners: observed 2, expected 1.27; millers: observed 4, expected 5.22). There were 3 deaths due to non-malignant respiratory disease against 10.9 expected (miners: observed 1, expected 2.5; millers: observed 2, expected 8.4). Mesothelioma, tuberculosis, or pneumoconiosis were not recorded as causes of death. Pneumoconiosis was noted as a contributory cause in three cases (silicosis two, talcosis one). Further follow-up will reduce any potential impact of "healthy worker" selection.
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PMID:Morbidity and mortality in talc-exposed workers. 232 17

The mortality risk of iron ore (haematite) miners between 1970 and 1982 was investigated in a retrospective cohort study of workers from two mines, Longyan and Taochong, in China. The cohort was limited to men and consisted of 5406 underground miners and 1038 unexposed surface workers. Among the 490 underground miners who died, 205 (42%) died of silicosis and silicotuberculosis and 98 (20%) of cancer, including 29 cases (5.9%) of lung cancer. The study found an excess risk of non-malignant respiratory disease and of lung cancer among haematite miners. The standardised mortality ratio for lung cancer compared with nationwide male population rates was significantly raised (SMR = 3.7), especially for those miners who were first employed underground before mechanical ventilation and wet drilling were introduced (SMR = 4.8); with jobs involving heavy exposure to dust, radon, and radon daughters (SMR = 4.2); with a history of silicosis (SMR = 5.3); and with silicotuberculosis (SMR = 6.6). No excess risk of lung cancer was observed in unexposed workers (SMR = 1.2). Among current smokers, the risk of lung cancer increased with the level of exposure to dust. The mortality from all cancer, stomach, liver, and oesophageal cancer was not raised among underground miners. An excess risk of lung cancer among underground mine workers which could not be attributed solely to tobacco use was associated with working conditions underground, especially with exposure to dust and radon gas and with the presence of non-malignant respiratory disease. Because of an overlap of exposures to dust and radon daughters, the independent effects of these factors could not be evaluated.
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PMID:Mortality experience of haematite mine workers in China. 232 25

The incidence of lung cancer among 280 silicotic men working in the ceramics industry and notified to the Swedish Silicosis Registry has been investigated. During the study period 1958-83, the risk of lung cancer (nine cases) was double that expected based on national rates. There was no increased incidence of cancer at any other site. The results are in agreement with those of both animal and epidemiological studies of quartz exposure and point to an increased risk of lung cancer, especially among silicotics. Various possible explanations of this increased risk are discussed, but further studies are required.
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PMID:Lung cancer incidence among Swedish ceramic workers with silicosis. 237 98


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