The study investigated whether occupational accident risks were equally distributed across age categories over time in the context of production reorganization and work rationalization in a Swedish iron ore mine between 1980 and 1993. Three phases of reorganization, defined by productivity levels, and four age categories were related to age-related accident risk ratios using the Poisson-regression method. Accident risk ratios (ARRs) were found systematically to be higher during the two first phases and also for younger workers, in the cases of both nonspecific and specific accident risks. The steady reduction in accident rates observed did not favor all age groups of workers to the same extent. For two accident patterns out of five, workers in their thirties and forties recorded higher ARRs than those in their fifties.
The career and work arduousness of a population of retired iron ore miners and their contemporaries who continued to work were investigated to find out what aspects of work history were associated with disability pensioning. The retired group had entered the mining industry at a more advanced age than the referents. The retired miners had also started at more strenuous tasks. Later they changed to lighter tasks, but were less often promoted in their career. The risk of early retirement seems thus to be related to the essential indicators of one's progress in the mining vocation.
Clinical and morphological features of cancer were observed in two groups of miners (of Krivoy Rog iron-ore and Zholty Vody uranium mines), working in hazardous labour conditions. In both of groups the disease course had typical features for lung cancer. Roentgenologic changes were observed, central cancer of left and right lung was revealed by bronchoscopy method. In all the cases lung cancer was morphologically proved and classified as squamous. Rapid progression of the disease and late medical aid appealability cause the patients consulted with their doctors only at the stage of II-III, sometimes III of the disease and it makes a distinction of lung cancer in miners of iron-ore and uranium mines. In order to prevent such a late diagnostics all the miners should be referred to the group of risk on lung cancer.
Within a case-control study of male lung carcinoma in northern Sweden combined effects of underground mining (iron ore mines) and smoking were analysed. A synergistic effect was found approximately of multiplicative type. Cases with lung carcinoma exposed to underground mining had a considerably lower average cumulative tobacco consumption than other lung carcinoma cases as an expression of the fact that smoking is particularly dangerous in underground miners. Small cell undifferentiated carcinoma was overrepresented among the cases exposed to underground mining and were especially often low tobacco consumers. In the 2 municipalities where the iron mines were located 74 per cent of the male lung carcinoma incidence could be explained by smoking and 55 per cent by underground mining (etiologic fractions).
OBJECTIVES: To assess the exposure-response relationship between exposure to quartz and fatal silicosis. METHODS: The mortality from silicosis in 7729 miners was analyzed and compared to their estimated exposure to respirable quartz. The miners had been working as a miner for at least 1 year between 1923 and 1996. Their mortality between 1952 and 2001 was studied by using information from the national cause of death register. Both underlying and contributing causes of death were considered in the analysis. The exposure to quartz was estimated from job titles and using 3239 measurements of personal exposure to respirable quartz from 1965 to 1999. The mortality rates were adjusted to attained age and years of birth using a Poisson regression. RESULTS: The median cumulative exposure among the 7729 miners was 0.9 mg x years m(-3). There were 58 deaths from silicosis. Their median cumulative exposure was 4.8 mg x years m(-3). The crude mortality rate was 53 cases per 100,000 person-years with an exposure-response relationship. CONCLUSION: There seems to be an increased risk of fatal silicosis at exposure levels around 3 mg x years m(-3) for respirable quartz.
OBJECTIVES: This study investigates both general mortality and mortality from myocardial infarction among men employed in iron-ore mines in Sweden. METHODS: The mortality of employees (surface and underground workers) at the iron-ore mines in Malmberget and Kiruna, Sweden was investigated. The study cohort comprised men who had been employed for at least 1 year between 1923 and 1996. The causes of death were obtained from the national cause of death register from 1952 to 2001. Indirect standardised mortality ratios (SMR) were calculated for four main causes. Mortality specifically from myocardial infarction was also analysed. RESULTS: 4504 deaths in the cohort gave an SMR for total mortality of 1.05 (95% CI 1.02 to 1.09). Mortality was significantly higher for lung cancer (SMR 1.73, 95% CI 1.52 to 1.97). There was an increased risk of injuries and poisonings (SMR 1.34, 95% CI 1.24 to 1.46) and respiratory diseases (SMR 1.14, 95% CI 1.00 to 1.28). There were 1477 cases of myocardial infarction, resulting in an SMR of 1.12 (95% CI 1.07 to 1.18). SMR was higher (1.35, 95% CI 1.22 to 1.50) for men aged 60 years of age (1.06, 95% CI 1.00 to 1.13). CONCLUSIONS: Mortality from myocardial infarction was higher than expected. There was also an increased risk of death from injuries and poisonings, lung cancer and respiratory diseases, as well as higher general mortality. Our findings support the results of previous studies that there is an association between working in the mining industry and adverse health outcomes.
In 1967, 240 workers in the Kiruna, Sweden, mine were examined with regard to lung function and respiratory symptoms. Seventeen years later, 167 of these workers were reexamined using a structured interview which covered respiratory symptoms, smoking habits, and workplace, and lung function tests, including dynamic spirometry and closing volume. The prevalence of chronic bronchitis in the present study was 9.6%. There was a strong relationship between chronic bronchitis and smoking but no relationship between chronic bronchitis and working underground in the mine. Only three persons had chronic obstructive lung disease. In the still active mine workers, dynamic spirometry results showed no difference between smokers or nonsmokers or between underground and surface workers. Thus, we found no excess of chronic obstructive lung disease or lung function disturbances in the mine workers studied. This probably reflects a self-selection process whereby the workers with airway obstruction due to smoking or underground exposure have left underground work and also the company. Underground workers with chronic mucous hypersecretion, on the other hand, have not felt motivated, because of this, to leave underground work. Some, however, may have stopped smoking but not necessarily because of the hypersecretion.