Mortality and cancer incidence in a copper-zinc cohort

Previous studies of copper-zinc workers have primarily observed significant increases in lung and other respiratory cancers. This study concurrently examined cancer incidence and cause-specific mortality for a cohort of workers at a copper-zinc producer in Ontario, Canada, from 1964 to 2005. Significant elevations in lung cancer incidence were observed for males in the overall cohort (standardized incidence ratio [SIR] = 124, 95% confidence interval [CI] = 102-150) and for surface mine (SIR = 272, 95% CI = 124-517), concentrator (SIR = 191, 95% CI = 102-327), and central maintenance (SIR = 214, 95% CI = 125-343) employees. Significant elevations of non-Hodgkin's lymphoma incidence were observed for male underground mine employees (SIR = 232, 95% CI = 111-426). Occupational etiology cannot be ascertained with the current exploratory study design. Future studies could (1) incorporate exposure assessment for subgroups within the existing cohort and (2) determine the efficacy of wellness programs in partnership with the local health unit.