[Prospective analysis of clinical course and outcomes in silicosis patients].

The authors revealed features of clinical course and outcomes in patients with silicosis and silicotuberculosis, who worked on iron industry enterprise. The article covers comparative analysis of survival rate and mortality among silicosis patients over 14 years of observation.

Mortality of workers compensated for silicosis during the period 1959-1963 in the Veneto region of Italy.

After reports appeared from other countries indicating an excess risk of lung cancer among silicotics, a cohort of workers compensated for silicosis during the period 1959-1963 in the Veneto region of Italy was constructed and followed for mortality through 1984. The results of the study showed a large mortality excess for infectious diseases (180 observed versus 9.5 expected), due to silicotuberculosis, and for diseases of the respiratory system (270 observed versus 33.5 expected) due to silicosis. An elevated standardized mortality ratio of 239 (70 observed versus 29.3 expected) from lung cancer was also detected. An increasing pattern was observed with time since first exposure, while the relationship with employment category and duration of exposure was less clear-cut. The lung cancer excess was also strongly associated with cigarette smoking, there being a dose-response relationship with daily cigarette consumption. The study confirms the results from other epidemiologic studies on silicotics which show this pathological condition to be associated with increased lung cancer mortality.

Mortality due to silico-tuberculosis and lung cancer among 200 whetstone cutters.

The objective of the present study was to examine if the mortality due to tuberculosis and cancer in the lungs was elevated in a cohort of 200 male whetstone cutters. 1955-1995 death certificate-based mortality data on the cohort were available, and the data were reviewed in the present study for mortality due to the two diseases to calculate standardized mortality ratios (SMR) in reference to the health statistics of Kyoto prefecture, where the cohort lived. Among the 200 cohort members, 99 men deceased during the observation period, the deaths including 10 cases of lung tuberculosis (of which 9 cases had silicosis together), 20 cases of all malignancies, and 6 cases of lung cancer (5 cases with silicosis). There was a significant elevation in the mortality due to lung tuberculosis (SMR = 3.47) although SMR for all causes was not elevated (1.10). There was no significant change in SMR for all malignancies (0.78), whereas SMR for lung cancer (1.24) tended to be elevated although insignificantly. Lung tuberculosis was a significant complication of silicosis in 1955-1995. Possible elevation in lung cancer SMR among this cohort needs further studies.

[Causes of mortality among workers exposed to inorganic dust containing crystalline silica]. / Przyczyny umieralnosci osób zawodowo narazonych na pyly nieorganiczne zawierajace krystaliczna krzemionke.

The authors briefly comment on the characteristics and results of recent epidemiological studies devoted to the reasons of mortality in persons exposed to dusts containing crystalline silica. The most important data concerning these studies are presented in the table accompanied by an author commentary which discusses results obtained by various authors and justification behind this subject in Poland.

[Effectivity of intermittent treatment in patients with sputum-positive silico-tuberculosis (author's transl)]. / Effektivität der intermittierenden Behandlung bei Patienten mit BK-positiver Siliko-Tuberkulose)

89 patients with sputum-positive silico-tuberculosis got a fully supervised administered antituberculous treatment with intermittent regimens during the years 1969-1974. 65 of the patients had a history of former antituberculous treatment. In only 5 patients the treatment was unsuccessful. Four of the relapses were observed between the 6th and 11th month of treatment. One patient had a relapse 56 months after the onset of chemotherapy. The results indicate that only the quality of the anti-TB treatment is of importance for the course of the tuberculous component in silico-tuberculosis. The results are comparable with those of uncomplicated TB of the lungs.

A study of the mortality of Cornish tin miners.

Increased mortality from cancer of the lung has been found in several studies of miners exposed to high levels of radioactivity in underground air. In view of their exposure to raised levels of radiation, we have studied the mortality of a group of men recorded as Cornish tin miners in 1939. Using occupational description, a crude classification of exposure was derived for these miners. The meaningfulness of this classification was supported by differences in mortality from silicosis and silicotuberculosis. A twofold excess of cancer of the lung was found for underground miners, while for other categories mortality from this cause was less than expected. This supports the findings of previous studies on exposure to radon and its daughters. An excess of cancer of the stomach was also observed among underground miners.

Vermont granite workers' mortality study.

A cohort mortality study was carried out in Vermont granite workers who had been employed between the years 1950 and 1982. The cohort included men who had been exposed to high levels of granite dust prior to 1938-1940 (average cutters to 40 million parts/cubic foot), and those employed at dust levels after 1940, which on average were less than 10 million parts/cubic foot. Deaths were coded by a qualified nosologist and standardized mortality ratios were calculated. The results confirm previous studies that show that death rates from silicosis and tuberculosis, the major health threats in the years before 1940, were essentially eliminated after dust controls. However, we found excessive mortality rates from lung cancer in stone shed workers who had been employed prior to 1930, and hence had been exposed to high levels of granite dust. When information was available, 100% of those dying from lung cancer had been smokers.

Mortality experience of haematite mine workers in China.

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.

Mortality among miners receiving workmen's compensation for silicosis in Ontario: 1940-1975.

We investigated mortality among 1,190 Ontario miners who received Workmen's Compensation awards for silicosis from 1940 through 1975. In comparison with the general population of Ontario these men had elevated all-cause mortality rates, with deaths attributed to nonmalignant respiratory diseases and tuberculosis being primarily responsible. The group of miners receiving their compensation awards between 1940 and 1959 has experienced more than twice as many lung cancer deaths as expected while men receiving compensation awards after 1959 have had lung cancer rates similar to the general population. It is concluded that silicosis is not a benign disease and that efforts must be continued to prevent its occurrence.

Mortality experience of Vermont granite workers.

The proportional mortality experience (1952-1978) of 969 deceased white male granite workers was compared with that of United States white males. Industrial hygiene information was combined with work histories to develop an estimate of lifetime granite dust exposure for each individual. Subjects were grouped into four cumulative exposure categories, and exposure-response relationships were examined. Trends of increasing silicosis and tuberculosis with increasing lifetime exposure were observed. These are consistent with earlier findings. With the exception of excess suicide among granite workers dying before 1970, there was little evidence of association between other causes of death and employment in the granite industry.

[Somatic diseases as cause of death of patients with active tuberculosis]. / Somaticheskie zabolevaniia kak prichina smerti bol'nykh aktivnym tuberkulezom.

Two hundred and fifteen case histories were studied to clarify causes of death in patients with active tuberculosis who had died from it. Males accounted for the largest proportion (86%) (n = 185). Patients above 50 years were 63.3% (n = 136). Two thirds were patients with restrictive tuberculosis without destruction and bacterial isolation. A hundred and fifty (70%) and 30% patients died from somatic diseases and other causes (sequels to alcohol abuse, violent death, suicide, etc.), respectively. Of the somatic diseases, cardiovascular diseases head the list, cancer ranks next to it, nonspecific respiratory diseases occupy the third place.

Mortality from lung cancer among silicotic patients in Sardinia: an update study with 10 more years of follow up.

OBJECTIVES: To evaluate the association between silica, silicosis and lung cancer, the mortality of 724 patients with silicosis, first diagnosed by standard chest x ray film between 1964 and 1970, has been analysed by a cohort study extended to 31 December 1997. METHODS: Smoking and detailed occupational histories were available for each member of the cohort as well as the estimated lifetime exposure to respirable silica dust and radon daughters. Two independent readers blindly classified standard radiographs according to the 12 point International Labour Organisation (ILO) scale. Lung function tests meeting the American Thoracic Society's criteria were available for 665 patients. Standardised mortality ratios (SMRs) for selected causes of death were based on the age specific Sardinian regional death rates. RESULTS: The mortality for all causes was significantly higher than expected (SMR 1.35, 95% confidence interval (95% CI) 1.24 to 1.46) mainly due to tuberculosis (SMR 22.0) and to non-malignant chronic respiratory diseases (NMCRD) (SMR 6.03). All cancer deaths were within the expected numbers (SMR 0.93; 95% CI 0.76 to 1.14). The SMR for lung cancer was 1.37 (95% CI 0.98 to 1.91, 34 observed), increasing to 1.65 (95% CI 0.98 to 2.77) allowing for 20 years of latency since the first diagnosis of silicosis. Although mortality from NMCRD was strongly associated to the severity of radiological silicosis and to the extent of the cumulative exposure to silica, SMR for lung cancer was weakly related to the ILO categories and to the cumulative exposure to silica dust only after 20 years of lag interval. A significant excess of deaths from lung cancer (SMR 2.35) was found among silicotic patients previously employed in underground metal mines characterised by a relatively high airborne concentration of radon daughters and among ever smokers who showed an airflow obstruction at the time of the first diagnosis of silicosis (SMR 3.29). Mortality for lung cancer related to exposure was evaluated with both the Cox's proportional hazards modelling within the entire cohort and a nested case-control study (34 cases of lung cancer and 136 matched controls). Both multivariate analyses did not show any significant association with cumulative exposure to silica or severity of silicosis, but confirmed the association between mortality for lung cancer and relatively high exposure to radon, smoking, and airflow obstruction as significant covariates. CONCLUSIONS: The findings indicate that the slightly increased mortality for lung cancer in this cohort of silicotic patients was significantly associated with other risk factors-such as cigarette smoking, airflow obstruction, and estimated exposure to radon daughters in underground mines-rather than to the severity of radiological silicosis or to the cumulative exposure to crystalline silica dust itself.

Estudio epidemiológico de la silicosis en las minas del Perú / An epidemiological study of silicosis in the mines of Peru

This epidemiological study attempts to determine the relation that exists between environmental factors and silicosis. Evaluation studies were conducted from 1949 to 1969 primarily in mines exploiting lead, zinc, and copper. These mines are located at altitudes of more than 3,000 meters above sea level and were selected because they present data of a statistically consistent and representative nature

The writer has determined that the equation adopted by the "American Conference of Governmental Industry Hygienists" of the United States of America to explain the permissible concentration of siliceous dust in the air is not applicable in Peru, because it represents a value that exceeds by two-and-a-half to three-and-a-half times the recommended concentration. He also discards the equation formulated by A. Yataco (see the Boletín de la OPS, August, 1967)

It should be noted that silicosis is the principal occupational illness - especially characteristic of Peru - which the Peruvian miners encounter and suffer, while working in the mines which are located 4,000 to 5,000 meters above sea level. In addition to this unique situation, the Peruvian miners also differ ethnically, dietetically and socially from miners in other countries

Without doubt, the element of height reduces the partial pressure of the atmospheric oxygen conditions affecting the worker's physiological reactions, namely the ... (AU)

Silicosis con corto tiempo de exposición / Silicosis with short exposure period

A study made of 1,901 cases of silicosis, in various stages, coming from mines located at different altitudes. Of these, 763 were a micronodular form of silicosis, 295 were macronodular, 253 were confluent and 590 were silicotuberculosis. The average working period for each stage of this affection was 10 years

Of the 1,901 cases, 344 (18.1 per cent) of the patients were found to have worked for less than five years in all. Of these cases 344, or 53.5 per cent were micro and macronodular in form and 46.5 per cent were confluent, with or without infection

Studies were made of 146 and 95 cases of silicosis, in various stages, coming from nine mines in a region with a high silicosis potential. The average working period was eight years and the percentage of cases with less than five years of work was 37.7 and 6.6

This situation shows that the trend of absenteeism is different in the two regions. In 2,027 and 3,319 cases of silicosis found in the mining regions of Huancavelica, Junin and Pasco, 77.7 per cent and 0.4 per cent had a work period of more than 20 years. Thus there is not stability in mining work because of the high risk involved

The conclusion to be drawn from these percentages is that silicosis is a serious public health problem in Peru, particularly in some mining regions, not only because of high-risk environmental conditions but because of the prevalence of tuberculosis ... (AU)