Mortality experience among Minnesota taconite mining industry workers.
Allen-EM; Alexander-BH; MacLehose-RF; Ramachandran-G; Mandel-JH
Occup Environ Med 2014 Nov; 71(11):744-749
Objective: To evaluate the mortality experience of Minnesota taconite mining industry workers. Methods: Mortality was evaluated between 1960 and 2010 in a cohort of Minnesota taconite mining workers employed by any of the seven companies in operation in 1983. Standardised mortality ratios (SMR) were estimated by comparing observed deaths in the cohort with expected frequencies in the Minnesota population. Standardised rate ratios (SRR) were estimated using an internal analysis to compare mortality by employment duration. Results: The cohort included 31,067 workers with at least 1 year of documented employment. Among those, there were 9094 deaths, of which 949 were from lung cancer, and 30 from mesothelioma. Mortality from all causes was greater than expected in the Minnesota population (SMR=1.04, 95% CI 1.02 to 1.04). Mortality from lung cancer and mesothelioma was higher than expected with SMRs of 1.16 for lung cancer (95% CI 1.09 to 1.23) and 2.77 for mesothelioma (95% CI 1.87 to 3.96). Other elevated SMRs included those for cardiovascular disease (SMR=1.10, 95% CI 1.06 to 1.14), specifically for hypertensive heart disease (SMR=1.81, 95% CI 1.39 to 2.33) and ischemic heart disease (SMR=1.11, 95% CI 1.07 to 1.16). Results of the SRR analysis did not show variation in risk by duration of employment. Conclusions: This study provides evidence that taconite workers may be at increased risk for mortality from lung cancer, mesothelioma, and some cardiovascular disease. Occupational exposures during taconite mining operations may be associated with these increased risks, but non-occupational exposures may also be important contributors.
Mining-industry; Miners; Mortality-data; Mortality-rates; Surveillance-programs; Statistical-analysis; Lung-cancer; Cancer; Mesothelial-cells; Cardiovascular-disease; Heart; Cardiovascular-system-disease
Dr. Bruce H. Alexander, University of Minnesota, School of Public Health, Division of Environmental Health Sciences, 420 Delaware Street SE, MMC 807, Minneapolis, MN 55455, USA
Occupational and Environmental Medicine
University of Minnesota Twin Cities