Bladder cancer in perfluorooctanesulfonyl fluoride manufacturing workers

Purpose: To determine whether bladder cancer is associated with exposure to perfluorooctane sulfonate (PFOS) in an occupational cohort. Methods: Incidence of bladder cancer was ascertained by postal questionnaire to all living current and former employees of the facility (N = 1895) and death certificates for deceased workers (N = 188). Exposure to PFOS was estimated with work history records and weighted with biological monitoring data. Standardized incidence ratios (SIRs) were estimated using U.S. population-based rates as a reference. Bladder cancer risk within the cohort was evaluated using Poisson regression by cumulative PFOS exposure. Results: Questionnaires were returned by 1,400 of the 1895 cohort members presumed alive. Eleven cases of primary bladder cancer were identified from the surveys (n = 6) and death certificates (n = 5). The SIRs were 1.28 (95% confidence interval [CI] = 0.64-2.29) for the entire cohort and 1.74 (95% CI = 0.64-3.79) for those ever working in a high exposed job. Compared with employees in the lowest cumulative exposure category, the relative risk of bladder cancer was 0.83 (95% CI = 0.15-4.65), 1.92 (95% CI = 0.30-12.06), and 1.52 (95% CI = 0.21-10.99). Conclusions: The results offer little support for an association between bladder cancer and PFOS exposure, but the limited size of the population prohibits a conclusive exposure response analysis.