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Coronary heart disease mortality among Newfoundland fluorspar miners
1Department of Preventive Medicine and Biostatistics, University of Toronto, Ontario, Canada.
Objectives:
The association between cumulative radon exposure and coronary heart disease mortality was studied in a retrospective cohort investigation of Newfoundland fluorspar miners.
Methods:
Multivariate Poisson regression techniques were used to estimate relative risks of coronary heart disease mortality by level of radon exposure. Relative risks (RR) were adjusted by attained age, calendar period, duration of exposure, and smoking status. Death from coronary heart disease was the outcome measure of interest and was identified by record linkage to the Canadian Mortality Database.
Results:
An elevated risk of mortality from coronary heart disease was observed among miners with a cumulative radon exposure exceeding 1000 working-level months [RR 1.5, 95% confidence interval (95% CI) 0.77-2.75]. The association between radon exposure and coronary heart disease was not statistically significant according to a test for trend across exposure categories (P = 0.09). The smokers were 1.8 times more likely than the nonsmokers to die from coronary heart disease (95% CI 1.1-2.8).
Conclusions:
These results suggest a positive association between coronary heart disease and radon exposure. However, these findings should be interpreted cautiously due to the inability to control for the confounding influence of other known risk factors of coronary heart disease.