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Biomedical subjects

E Hnizdo

Publications and source records attributed to E Hnizdo.

At least 19 recordsLinked to original sources
PubMed1992

Health risks among white South African goldminers--dust, smoking and chronic obstructive pulmonary disease.

The South African goldmining industry employs a large labour force exposed to several health hazards, of which one of the most important is underground dust, containing a high level of free crystalline silica (30%). Inhalation of silica dust can cause chronic obstructive pulmonary disease (COPD). The present paper reviews the epidemiological evidence on COPD in white South African goldminers. COPD emerges as a major cause of disability and increased mortality. The associated risk factors are smoking and combined exposure to dust and smoking. In conclusion, decreased tobacco consumption in white goldminers would in most cases prevent serious lung function impairment and the premature deaths associated with it.

Dust↗
PubMed1992

Lung function in silicosis.

In order to assess the effect of silicosis on lung function, 61 gold miners with radiological silicosis were compared with 61 controls. Each pair was matched for age, dust exposure, and smoking habits. A full range of lung function tests was performed, and with two exceptions the results showed no significant differences between the two groups. The exceptions are the slope of the alveolar plateau (phase 3) and the closing volume, for which the silicotic cases had significantly higher values. The reason for the higher readings in the silicotic patients remains unexplained.

Blood Gas Analysis↗
PubMed1992

Loss of lung function associated with exposure to silica dust and with smoking and its relation to disability and mortality in South African gold miners.

The data from a lung function study on 2209 white 45-54 year old South African gold miners in 1968-71 and at a five year follow up examination, were analysed to establish the actual loss of lung function associated with exposure to silica dust and with smoking. Ex-smokers were excluded from the analysis. Of the remaining 1625 subjects, 1249 had the five year follow up test of lung function. The estimated excess loss of lung function for a 50 year old gold miner, associated with 24 years of underground dust exposure of an average respirable dust concentration of 0.30 mg m-3 (14.4 ghm-3) was 236 ml of FEV1 (95% confidence interval (95% CI 134-337) and 217 ml of FVC (95% CI 110-324). By comparison, the effect of smoking one packet of cigarettes a day over 30 years was associated with an estimated loss of 552 ml of FEV1 (95% CI 461-644) and 335 ml of FVC (95% CI 170-500). The cumulative dust exposure was not associated with the longitudinal loss of FEV1 or FVC when the initial FEV1 and FVC were adjusted in the models. According to the predicted values, however, gold miners appear to have a greater loss of lung function from 50 to 55 years of age than that predicted for a general population.

Aged↗
PubMed1991

Relevance of airflow obstruction and mucus hypersecretion to mortality.

A group of 2,065 gold miners surveyed between 1968 and 1970 was followed to 31 December 1986, at which date 859 were known to be dead. The relationship between airways obstruction and mucus hypersecretion to causes of mortality was analyzed. Airways obstruction was strongly related to mortality from chronic obstructive pulmonary disease (COPD), lung cancer, coronary heart disease and other causes. After standardization for airways obstruction, mucus hypersecretion was not related to mortality from COPD but remained related to mortality from ischaemic heart disease (IDH) and other causes, even after adjustment for tobacco smoking and dust exposure. Mucus hypersecretion was not related to mortality from lung cancer when standardized for airways obstruction.

Airway Obstruction↗
PubMed1991

Silica exposure, silicosis, and lung cancer: a mortality study of South African gold miners.

The effects of exposure to gold mining dust with a high concentration of free silica and tobacco smoking on mortality from lung cancer was assessed in a sample of 2209 white South African gold miners who started mining exposure during 1936-43, and were selected for a study of respiratory disorders in 1968-71 when they were aged 45-54. The mortality follow up was from 1968-71 to 30 December 1986. The relative risk for the effect of dust cumulated to the start of the follow up period was estimated as 1.023 (95% confidence interval (CI) 1.005-1.042) for a unit of 1000 particle-years. The combined effect of dust and tobacco smoking was better fitted by the multiplicative model than the additive model, suggesting that the two exposures act synergistically. No association between lung cancer and silicosis of the parenchyma or pleura was found, but a positive association existed between silicosis of the hilar glands and lung cancer.

Cohort Studies↗
PubMed1991

Emphysema type in relation to silica dust exposure in South African gold miners.

The relationship between silica dust exposure in gold mines and the type of emphysema was studied in a group of 1,553 white gold miners who had undergone autopsy examination between 1974 and 1987. Of particular interest was the contrast between centriacinar and panacinar emphysema as they relate to silica exposure and the presence of silicosis. Subjects with significant emphysema, that is, with an emphysema score of 30% or more, were classified as having predominantly panacinar or predominantly centriacinar emphysema, and compared to those without emphysema (emphysema score less than or equal to 10%). Of those who had significant emphysema (greater than or equal to 30%), 24% had predominantly panacinar, 43% predominantly centriacinar, and 33% were classified as mixed. The odds ratios (OR) for the association between each emphysema type and dust exposure (one unit of the cumulative dust index) were found to be statistically significant and of equal magnitude [1.019, with a 95% confidence interval (CI) of 1.005 to 1.033 for panacinar and 1.019 with a 95% CI of 1.007 to 1.031 for centriacinar emphysema]. In 163 nonsmokers insignificant panacinar emphysema was more common than centriacinar emphysema. The results indicate that a miner with 20 yr in high-dust occupations has a 3.5 (1.7;6.6) times higher odds of having a significant degree of emphysema at autopsy than a miner not in a dusty occupation. This is likely to be true of smoking miners only because there were only four nonsmokers with an emphysema score between 30 and 40%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Evidence for an amphibole asbestos threshold exposure for asbestosis assessed by autopsy in South African asbestos miners.

In an attempt to determine whether there exists a threshold asbestos dose below which asbestosis does not occur, data on 807 men who had worked on amphibole asbestos mines and undergone autopsy were analysed. When exposure was expressed as fibre-years no asbestosis was found at autopsy when exposure was up to 2 fibre-years, even after 31-45 years of residence time. In the group exposed to greater than 2-5 fibre-years asbestosis was found. When exposure was expressed as average fibre concentration asbestosis occurred below 2 fibres per ml (f ml-1) and the prevalence increased with residence time. In conclusion, if a threshold dose for asbestosis does exist it is at approximately 2 fibre-years if off-shift exposure is ignored.

Adolescent↗
PubMed1990

Silica exposure, silicosis, and lung cancer: a necropsy study.

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).

Aged↗
PubMed1990

Combined effect of silica dust and tobacco smoking on mortality from chronic obstructive lung disease in gold miners.

A sample of 2209 white South African gold miners aged 45-54 between 1968-71, who started mining exposure during 1936-43, was investigated from 1968-71 to 30 December 1986. The effect of silica dust and tobacco smoking on mortality from chronic obstructive lung disease (COLD) was assessed. The relative risk (RR) for dust exposure before 1950 was estimated as 2.5 (95% confidence interval (CI) 1.5-4.2), for 10 units of 1000 particle-years. The combined effect of dust exposure before 1950 and years of cigarette smoking on mortality from COLD was best estimated by the multiplicative model, indicating that the two exposures act synergistically. All those that died of the disease were smokers. According to the estimates of attributable risk about 5% of the deaths from COLD were from the effect of dust, 34% were from smoking, and 59% were from the combined effect of dust and smoking. In conclusion, the results indicate that workers exposed to silica dust who smoke are at higher risk of dying from COLD than smokers not exposed to silica dust, as the two exposures act synergistically in causing COLD.

Aged↗
PubMed1990

Combined effect of silica dust exposure and tobacco smoking on the prevalence of respiratory impairments among gold miners.

The combined effect of underground gold mining dust with a high content of free silica and tobacco smoking on the prevalence of respiratory impairment was examined among 2209 South African gold miners and 483 nonminers. The subjects were grouped as having normal function; minimal, moderate or marked obstruction; marked obstruction with restriction; or pure restriction on the basis of their lung function profiles. Each profile group was compared with the normal group for exposure prevalences, and additive and multiplicative relative risk models were applied to test for departure from the additivity of individual effects. Departure from additivity was found to increase progressively with the severity of obstructive impairment. The results indicated that approximately 94% of the cases with the most severe respiratory impairment (N = 191) could have been prevented through the elimination of tobacco smoking. In conclusion, tobacco smoking was found to potentiate the effect of dust on respiratory impairments.

Bronchitis↗
PubMed1989

Addisonian crisis induced by treatment with rifampicin.

A patient with spinal tuberculosis and subclinical adrenal tuberculosis who developed acute Addisonian crisis on starting anti-tuberculosis therapy including rifampicin is reported. The possibility that many patients with tuberculosis have adrenal involvement with limited hormonal reserve and that they may develop incipient adrenal failure on commencing treatment is discussed.

Addison Disease↗
PubMed1989

Progression of irregular opacities in asbestos miners.

All white and mixed race men who were employed in South African asbestos mines and mills between 30 November 1970 and 30 November 1975 were studied. The men who had two radiographs available, the first taken some time between the above two dates and the latest available radiograph which had to be at least two years after the first one numbered 1454: 793 continued exposure after the first radiograph and 661 did not. The films were read by a panel of three readers. Data available included age, years of exposure to asbestos and other mining, intensity of exposure to asbestos and other dust, and smoking habit. Progression was expressed as the difference between the average readings of radiograph 2--radiograph 1 in minor categories per year of irregular opacities. Changes in pleural abnormality were also measured. No differences of progression in the profusion or change in size of the irregular opacities were found between the two groups or in the number of zones affected. "New attacks" appeared equally frequently between the two groups. No difference in the change in extent of any type of pleural change was seen. It appears that once a dose of asbestos sufficient to initiate the disease has been retained it is inexorably progressive.

Asbestos↗
PubMed1988

Effect of tobacco smoking on the presence of asbestosis at postmortem and on the reading of irregular opacities on roentgenograms in asbestos-exposed workers.

A statistically significant association between cigarette smoking and radiologic readings of irregular opacities was observed in a case-control study of 430 South African asbestos miners (OR = 3.03; 95% confidence interval, 1.50; 6.11). In another case-control study of 487 dead South African asbestos miners, no positive association between smoking and autopsy findings for asbestosis was observed (OR = 0.50; 95% confidence interval, 0.20; 1.29). The association between greater than slight asbestosis (moderate and marked) and smoking (yes/no) was not significant (Fisher's exact test, p = 0.44), and the adjusted odds ratio was 1.25 with 95% confidence interval (0.20; 7.78). In addition, the certification in life for asbestosis, based on chest roentgenogram readings for irregular opacities, was also found to have a tendency to be related to smoking. Thus, the findings of these studies do not support the hypothesis that smoking is associated with the presence of asbestosis at autopsy or that smoking and asbestos dust act synergistically in producing asbestosis at autopsy. But the findings of this and other studies suggest that smoking does produce some change in the lung structure that can be visible on the roentgenogram and can be wrongly interpreted as irregular opacities caused by asbestosis.

Asbestos↗
PubMed1987

Pathological findings in mine workers: I. Description of the PATHAUT database.

A computerized system for recording the results of structured, numerically coded autopsy reports on various types of mine workers has been in operation at the National Centre for Occupational Health in Johannesburg since 1975. Historical developments, particularly those associated with compensation for occupational disease, have resulted in very high autopsy rates, especially among whites. Since its inception, the pathology automation (PATHAUT) system has accumulated the results of more than 33,000 autopsies. The data set is described in the hope of stimulating interest in the possible uses of the data and encouraging collaborative research. Some characteristics of the database with potential research implications are discussed. These include differing age and work patterns for blacks and whites and geographic factors with potential influence on whether a body or only the cardiorespiratory organs are sent for examination.

Autopsy↗
PubMed1987

Pathological findings in mine workers: II. Quality of the PATHAUT data.

To assess the feasibility of using the pathology automation system (PATHAUT) for research, the quality of the data was explored by examining who comes to autopsy, the quality of the autopsy material, interobserver variability, and repeatability of diagnoses. The data indicated that autopsy rates in the gold mining industry, especially for whites, are high and that even among blacks, gold miners are represented in proportions exceeding the relative size of the working population. Because of the perception of the autopsy service as a means of obtaining compensation, miners with occupational diseases fully compensated in life are probably underrepresented. The autopsy material submitted for full autopsy is generally better preserved than cardiorespiratory organs that are sent for examination. The gold mining industry has a high proportion of full autopsies as does the Iron and Steel Corporation of South Africa. Full autopsies are more commonly performed on older deceased miners. This was true for both blacks and whites. The allocation of material to pathologists for full autopsies and examinations of the cardiorespiratory organs were clearly not random, and this may affect comparisons among pathologists. Active tuberculosis, silicosis, and emphysema prevalences appeared fairly comparable across pathologists; however, there was wide variability in the prevalence of bronchiolitis as determined by the pathologists. Agreement between the diagnoses on PATHAUT and reclassifications by single pathologists was very good for the severity of emphysema and the histological type of bronchogenic carcinoma.

Autopsy↗
PubMed1986

Case-control study of silicosis, silica exposure, and lung cancer in white South African gold miners.

A case-control study was undertaken to assess the association between lung cancer and silicosis or silica dust exposure in white South African gold miners. Cases and controls were identified from deaths reported to the Gold Miners Provident Fund for the period January, 1979-October, 1983. Two controls were matched to each case by year of birth (+/- 2 years) and by smoking (+/- 5 cigarettes or equivalents per day) assessed 10 years (+/- 2 years) prior to death. One hundred thirty-three matched triplets were identified. The results showed no overall association between lung cancer and radiological silicosis (OR = 1.08, p = 0.92). Autopsy data indicated no overall associations between lung cancer and silicosis of the lung parenchyma (OR = 1.49, p = 0.11), the pleura (OR = 0.72, p = 0.30), or the hilar glands (OR = 0.85, p = 0.72). A trend toward increased severity of silicosis of the parenchyma was evident; however, this was not statistically significant (p = 0.08). Odds ratios for lung cancer and silicosis were higher at lower levels of cumulative silica dust exposure (ORs = 2.43, 1.72, 1.35 and 0.62 for lung cancer and autopsy silicosis of the parenchyma for the lowest, second, third, and highest quartiles of dust exposure, respectively; all p greater than 0.05). Cases did not differ from controls for total silica dust exposure, length of exposure, weighted average intensity of exposure, or number of shifts at high dust (all p greater than 0.20). The data do not support the hypothesis of a carcinogenic role for silica dust and no statistically significant associations were found between lung cancer and silicosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Gold↗
PubMed1986

Relationship between silicosis and rheumatoid arthritis.

The relationship between rheumatoid arthritis and silicosis was studied by means of a case-control study in South African gold miners. One hundred and fifty seven miners with rheumatoid arthritis classified as "definite" (91) or "probable" (66) were individually matched by year of birth with miners who had no evidence of rheumatoid arthritis. Unmatched analysis of the case-control status for "probable" and "definite" cases yielded an odds ratio of 2.84 (p = 0.0001). Separate analyses yielded an odds ratio of 3.79 (p = 0.0006) for "definite" cases, a non-significant odds ratio for "probable" cases, and an odds ratio of 5.00 (p = 0.0003) for the presence of rheumatoid factor. These results could not be explained on the basis of cumulative dust exposure or intensity of exposure. The rate of progression of silicosis in both the "definite" and the "probable" groups was greater than for the control patients with silicosis, as was the probability of silicosis presenting at the start with larger nodules (type r).

Arthritis, Rheumatoid↗