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

Controversy regarding the association between silicosis and lung cancer has been clouded by the fact that studies examining this association generally do not include information on smoking. A causal association between smoking and silicosis would seriously confound the association between silicosis and lung cancer. The current analysis assessed the association between silicosis and smoking using data on deceased white gold miners who underwent postmortem examination between 1976 and 1981. Smoking histories and exposure information were available. A subset analysis in a group of deceased miners for whom more detailed smoking and exposure information was available confirmed the findings of the larger analysis. Both analyses showed a slight inverse relationship between smoking and silicotic collagenization of the parenchyma and a stronger negative relationship between smoking and silicotic collagenization of the pleura, controlling for age and cumulative exposure to silica dust. No association between silicotic collagenization of the hilar glands and smoking was detected. The data should not be construed as advocating that workers exposed to silica dust should smoke. The hazards of cigarette smoking are likely to far outweigh the hazards of silicosis. The data suggest that the lack of smoking histories in studies of the association between silicosis and lung cancer probably does not seriously confound risk estimates. The distribution of silicotic collagenization in the lungs of smokers and nonsmokers is consistent with enhanced mucus interception, more central deposition in the lungs, and proportionally more lymphatic clearance to the hilum (as opposed to the pleura) of silica particles in smokers compared to nonsmokers.
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PMID:Distribution of silicotic collagenization in relation to smoking habits. 185 51

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

The mortality of 724 subjects with silicosis, first diagnosed in 1964-70 in the Sardinia region of Italy, was followed up through to 31 December 1987. Smoking, occupational history, chest x ray films, and data on lung function were available from clinical records for each member of the cohort. The overall cohort accounted for 10,956.5 person-years. The standardised mortality ratios (SMRs) for selected causes of death (International Classification of Diseases (ICD) eighth revision) were based on the age specific regional death rates for each calendar year. An excess of deaths for all causes (SMR = 1.40) was found, mainly due to chronic obstructive lung disease, silicosis, and tuberculosis with an upward trend of the SMR with increasing severity of the International Labour Office (ILO) radiological categories. Twenty two subjects died from lung cancer (SMR = 1.29, 95% confidence interval (95% CI) = 0.8-2.0). The risk increased after a 10 and 15 year latency but the SMR never reached statistical significance. No correlation was found between lung cancer and severity of the radiological category, the type of silica (coal or metalliferous mines, quarries etc), or the degree of exposure to silica dust. A significant excess of deaths from lung cancer was found among heavy smokers (SMR = 4.11) and subjects with airflow obstruction (SMR = 2.83). A nested case-control study was planned to investigate whether the association between lung cancer and airway obstruction was due to confounding by smoking. No association was found with the ILO categories of silicosis or the estimated cumulative exposure to silica. The risk estimate for lung cancer by airflow obstruction after adjusting by cigarette consumption was 2.86 for a mild impairment and 7.23 for a severe obstruction. The results do not show any clear association between exposure to silica, severity of silicosis, and mortality from lung cancer. Other environmental or individual factors may act as confounders in the association between silicosis and lung cancer. Among them, attention should be given to chronic airways obstruction as an independent risk factor for lung cancer in patients with silicosis.
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PMID:Mortality from lung cancer among Sardinian patients with silicosis. 199 6

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 association between silicosis and lung cancer mortality was estimated in 9,912 (369 silicotics and 9,543 nonsilicotics) white male metal miners. These miners were examined by the U.S. Public Health Service during 1959-1961 and were followed through 1975. Miners were excluded from this study if they were employed in a mine during 1959-1961 that used diesel equipment underground. The ores that were mined consisted of copper, lead-zinc, iron, mercury, lead silver, gold and gold-silver, tungsten, and molybenum. The standardized mortality ratio (SMR, U.S. white male rates) for lung cancer was 1.73 (95% CI: .94-2.90) in silicotics and 1.18 (95% CI: .98-1.42) in nonsilicotics. Additionally, SMRs were higher in silicotics than in nonsilicotics, even in most subgroups stratified by cigarette smoking habit, type of ore mined, years of service in an underground job, radon exposure group, or year of hire. When lung cancer mortality between silicotics and nonsilicotics was compared, the age-adjusted rate ratio (95% CI) was 1.56 (.91-2.68), and the age- and smoking-adjusted rate ratio was 1.96 (.98-3.67). Corresponding figures for miners who were employed in mines with low levels of radon exposure were 1.90 (.98-3.67) and 2.59 (1.44-4.68), respectively. These findings indicate that lung cancer mortality risk was increased in silicotics, and this probably did not result from chance or bias. However, confounding from radon exposure could not be ruled out. The findings indicate that further follow-up of this cohort is needed.
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PMID:Silicosis and lung cancer in U.S. metal miners. 200 98

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 results of 102 cases of diffuse or peripheral lung lesions examined by transbronchial lung biopsy (TBLB), bronchial brushing (BB), and bronchial alveolar lavage (BAL) via fiberoptic bronchoscope, were reported. The positive diagnostic rate was 74.5% (76 cases). In lung cancer, the positive rate by means of BB was 77.1%, which was higher than that by TBLB (58.1%). In pulmonary tuberculosis, the positive rate by TBLB was 76.9%, higher than that by BAL fluid for identification of tubercle bacillus by culture (44.4%). If TBLB was combined with BB and BAL, the positive diagnostic rate would be further elevated. The data showed that if the size of the masses greater than or equal to 3cm in peripheral lung field on chest film, the possibility of lung cancer was greater than that of those less than 3cm. Most cases of localized infiltration in the lungs were caused by tuberculosis. But the diffuse lesions of the lungs were often caused by bronchiolo-alveolar carcinoma, adenocarcinoma, diffuse interstitial fibrosis of the lungs, silicosis, sarcoidosis, etc. By the careful study of the chest film and ascertainment of the exact locations of the pulmonary lesions there, we can carry out the TBLB and obtain a satisfactory specimen without any X-ray monitoring. In the present group of patients who underwent TBLB, one was complicated by haemorrhage (greater than 50ml) and two by pneumothorax, but all of them recovered promptly after proper management. By strick adherence to indication, adequate preoperative preparations and very careful performance of the procedure, the complications of TBLB could be reduced to minimum.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Diagnostic value of transbronchial lung biopsy in diffuse or peripheral lung lesions]. 209 76

Recent studies of the association between lung cancer and silicosis and silica dust have been inconclusive; some showing positive association and some showing none. The present study matched 231 cases of lung cancer with 318 controls by year of birth. Subjects were selected from the necropsy records of the National Centre for Occupational Health. Data on intensity and duration of exposure to silica dust were obtained from personnel records. Presence or absence of lung cancer and the presence and severity of silicosis of the parenchyma, pleura, and hilar glands were documented from necropsy reports. Smoking data were abstracted from records of routine examinations. No case-control differences were noted for any of the exposure indicators including cumulative dust exposure, total dusty shifts, weighted average intensity of exposure, total underground shifts, and shifts in high dust. Similarly, no association was found between lung cancer and the presence or severity of silicosis and any site. Stratified analyses showed neither significant nor suggestive trends when case-control comparisons for silicosis were examined by level of dust exposure or smoking. Reasons for disparity between these results and those of some other studies may include concomitant exposures to radon daughters, asbestos, diesel emissions, and cigarette smoking; idiosyncracies of the compensation process; and the possibility of a threshold in the relation(s).
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PMID:Silica exposure, silicosis, and lung cancer: a necropsy study. 215 48

A case-referent study has been carried out to test the hypothesis that silica-exposed ceramic workers have an increased risk of lung cancer. Next-of-kin interviews were conducted for 72 lung cancer cases and 319 referents, all deceased, to collect work histories and smoking habits. The diagnosis of silicosis was ascertained by checking the individual files of cases of silicosis where compensation had been received. It was found that, after controlling for age, period of death and smoking, workers in the ceramic industry had a higher lung cancer risk than those in other occupations in which there was no exposure to silica (Mantel-Haenszel rate ratio = 2.0; 95% confidence interval (CI) = 1.1-3.5). This increased risk was mainly due to a rate ratio of 3.9 (95% CI = 1.8-8.3) for silicotic individuals, while for non-silicotic ceramic workers it was only 1.4 (95% CI = 0.7-2.8). Exposure to other carcinogens in the workplace seems not to play any role in the development of lung cancer. Furthermore, the data do not suggest an increased risk for silicotic non-smokers. The results of the study tend to confirm previous evidence of an excess risk among silicotic subjects and points to a possible etiological role of the silicotic process itself in lung cancer.
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PMID:A case-referent study on lung cancer mortality among ceramic workers. 216

Following reports from other countries indicating an excess risk of lung cancer among silicotics, a historical cohort of workers employed for at least one year at a company in charge of slate extraction and processing during the period 1953-1985 in the German Democratic Republic has been constructed and followed up for mortality from 1970 to 1985. The results of the study show a mortality excess for infectious and respiratory diseases. The overall lung cancer mortality is not in excess but shows a tendency to increase with time since first exposure. A mortality excess from lung cancer is concentrated among workers receiving compensation for silicosis, suggesting a possible carcinogenic risk for individuals suffering from this pathological condition.
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PMID:A mortality study of a cohort of slate quarry workers in the German Democratic Republic. 216 3


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