Cancer risk in aluminum reduction plant workers (Canada)

A 14-year update to a previously published historical cohort study of aluminum reduction plant workers was conducted [1]. All men with three or more years at an aluminum reduction plant in British Columbia (BC), Canada between the years 1954 and 1997 were included; a total of 6,423 workers. A total of 662 men were diagnosed with cancer, representing a 400% increase from the original study. Standardized mortality and incidence ratios were used to compare the cancer mortality and incidence of the cohort to that of the BC population. Poisson regression was used to examine risk by cumulative exposure to coal tar pitch volatiles (CTPV) measured as benzene soluble materials (BSM) and benzo(a)pyrene (BaP). The risk for bladder cancer was related to cumulative exposure to CTPV measured as BSM and BaP (p trends <0.001), and the risk for stomach cancer was related to exposure measured by BaP (p trend BaP <0.05). The risks for lung cancer (p trend <0.001), non-Hodgkin lymphoma (p trend <0.001), and kidney cancer (p trend <0.01) also increased with increasing exposure, although the overall rates were similar to that of the general population. Analysis of the joint effect of smoking and CTPV exposure on cancer showed the observed dose-response relationships to be independent of smoking.