Mortality among Workers Exposed to Polychlorinated Biphenyls (PCBs) in an Electrical Capacitor Manufacturing Plant in Indiana: An Update Avima M. Ruder, Misty J. Hein, Nancy Nilsen, Martha A. Waters, Patricia Laber, Karen Davis-King, Mary M. Prince, and Elizabeth Whelan National Institute for Occupational Safety and Health, Cincinnati, Ohio, USA Abstract An Indiana capacitor-manufacturing cohort (n = 3,569) was exposed to polychlorinated biphenyls (PCBs) from 1957 to 1977. The original study of mortality through 1984 found excess melanoma and brain cancer ; other studies of PCB-exposed individuals have found excess non-Hodgkin lymphoma and rectal, liver, biliary tract, and gallbladder cancer. Mortality was updated through 1998. Analyses have included standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) using rates for Indiana and the United States, standardized rate ratios (SRRs) , and Poisson regression rate ratios (RRs) . Estimated cumulative exposure calculations used a new job-exposure matrix. Mortality overall was reduced (547 deaths ; SMR, 0.81 ; 95% CI, 0.7-0.9) . Non-Hodgkin lymphoma mortality was elevated (9 deaths ; SMR, 1.23 ; 95% CI, 0.6-2.3) . Melanoma remained in excess (9 deaths ; SMR, 2.43 ; 95% CI, 1.1-4.6) , especially in the lowest tertile of estimated cumulative exposure (5 deaths ; SMR, 3.72 ; 95% CI, 1.2-8.7) . Seven of the 12 brain cancer deaths (SMR, 1.91 ; 95% CI, 1.0-3.3) occurred after the original study. Brain cancer mortality increased with exposure (in the highest tertile, 5 deaths ; SMR, 2.71 ; 95% CI, 0.9-6.3) ; the SRR dose-response trend was significant (p = 0.016) . Among those working ≥ 90 days, both melanoma (8 deaths ; SMR, 2.66 ; 95% CI, 1.1-5.2) and brain cancer (11 deaths ; SMR, 2.12 ; 95% CI, 1.1-3.8) were elevated, especially for women: melanoma, 3 deaths (SMR, 5.99 ; 95% CI, 1.2-17.5) ; brain cancer, 3 deaths (SMR, 2.87 ; 95% CI, 0.6-8.4) . These findings of excess melanoma and brain cancer mortality confirm results of the original study. Melanoma mortality was not associated with estimated cumulative exposure. Brain cancer mortality did not demonstrate a clear dose-response relationship with estimated cumulative exposure. Key words: cancer, cohort study, exposure assessment, occupational exposure, polychlorinated biphenyls. Environ Health Perspect 114:18-23 (2006) . doi:10.1289/ehp.8253 available via http://dx.doi.org/ [Online 1 September 2005]
Address correspondence to A. Ruder, National Institute for Occupational Safety and Health, Mailstop R-16, 4676 Columbia Parkway, Cincinnati, OH 45226 USA. Telephone: (513) 841-4440. Fax: (513) 841-4486. E-mail: amr2@cdc.gov Supplemental Material is available online at http://ehp.niehs.nih.gov/docs/2005/8253/supplement.pdf We thank T. Schnorr, L. Pinkerton, T. Sinks, and the reviewers for their valuable comments. We also thank C. Gersic and V. Drake for assistance in data preparation and L. Schoolfield for assistance in retrieving relevant literature. This study was entirely funded by National Institute for Occupational Safety and Health (NIOSH) base operating funds. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of NIOSH. The authors declare they have no competing financial interests. Received 26 April 2005 ; accepted 1 September 2005. The full version of this article is available for free in HTML or PDF formats. |