Fifty-year follow-up of mortality among a cohort of iron-ore miners in Sweden, with specific reference to Myocardial Infarction Mortality

Objectives This study investigates both general mortality and specifically from myocardial infarction among men employed in iron-ore mines in Sweden. Methods This mortality study investigated all employees (surface and underground workers) at the iron-ore mines in Malmberget and Kiruna, Sweden. The...

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Bibliographic Details
Published in:Occupational and Environmental Medicine
Main Authors: Björ, Bodil, Burström, Lage, Jonsson, Håkan, Nathanaelsson, Lena, Damber, Lena, Nilsson, Tohr K.F.
Format: Text
Language:English
Published: BMJ Publishing Group Ltd 2008
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Online Access:http://oem.bmj.com/cgi/content/short/oem.2008.040147v1
https://doi.org/10.1136/oem.2008.040147
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Summary:Objectives This study investigates both general mortality and specifically from myocardial infarction among men employed in iron-ore mines in Sweden. Methods This mortality study investigated all employees (surface and underground workers) at the iron-ore mines in Malmberget and Kiruna, Sweden. The study cohort comprised men who had been employed for at least one year from 1923 up to 1996. The causes of death were obtained from the national cause of death register from 1952 to 2001. Indirect standardized mortality ratios (SMR) were calculated for four main causes. In addition, mortality specifically from myocardial infarction was analyzed. Results A total of 4504 deaths in the cohort gave an SMR for total mortality of 1.05 (95% CI 1.02-1.09). Mortality was significantly higher for lung cancer (SMR 1.73, 95% CI 1.52-1.97). There was an increased risk of injuries and poisonings (SMR 1.34, 95% CI 1.24-1.46) and respiratory diseases (SMR 1.14, 95% CI 1.00-1.28). There were 1477 cases of myocardial infarction, a result that corresponds to an SMR of 1.12 (95% CI 1.07-1.18). SMR was higher (1.35, 95% CI 1.22-1.50) for men aged 60 years and younger than for those over 60 years of age (1.06, 95% CI 1.00-1.13). 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 from previous studies; there is an association between working in the mining industry and adverse health outcomes.