Ischaemic heart disease mortality study among workers with occupational exposure to ammonium perfluorooctanoate

Objectives: Ammonium perfluorooctanoate (APFO) is a biopersistent surfactant used in the manufacture of several types of fluoropolymers. Based on previous findings of increased serum lipid levels associated with exposure to APFO, we evaluated ischaemic heart disease (IHD) mortality in a cohort of occupationally exposed workers. Methods: Relative risks (RR) were estimated from exposure-response analyses of cumulative exposure measures using proportional hazards regression models. Results: 239 IHD deaths have occurred in the cohort of 4747 workers with work histories from 1948 through 2002. RR estimates indicate no statistically significant increased mortality risk for IHD associated with estimated cumulative exposure. We observed a positive trend only at an exposure lag of 10 years. This finding was not reproduced in other 5-year exposure lags and was attenuated when different cutpoints for exposure categorisation were used. Conclusion: This exposure-response study shows no convincing evidence of increased IHD mortality risk for APFO-exposed workers at this plant. Further studies evaluating the incidence of IHD are being conducted.