An Indiana capacitor-manufacturing cohort (n=3,569) was exposed to polychlorinated biphenyls (PCBs) 1957-1977. The original study of mortality through 1984 found excess melanoma and brain cancer; other studies of PCB-exposed individuals have found excess non-Hodgkins lymphoma, rectal cancer and liver, biliary tract, and gall bladder cancer. Mortality was updated through 1998. Analyses included standardized mortality ratios (SMR) and 95% confidence intervals (CI) using Indiana (shown below) and U. S. rates, standardized rate ratios (SRR) and Poisson regression rate ratios (RR). Estimated cumulative exposure calculations used a new jobexposure matrix. Mortality overall was reduced (547 deaths, SMR 0.81, CI 0.7-0.9). Non- Hodgkins lymphoma mortality was elevated (9 deaths, SMR 1.23, CI 0.6-2.3). Melanoma remained in excess (9 deaths, SMR 2.43, CI 1.1-4.6), especially in the lowest tertile of estimated cumulative exposure (5 deaths, SMR 3.72, CI 1.2-8.7). Seven of the 12 brain cancer deaths (SMR 1.91, 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, 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, CI 1.1-5.2) and brain cancer (11 deaths, SMR 2.12, CI 1.1-3.8) were elevated, especially for women: 3 deaths (SMR 5.99, CI 1.2-17.5) and 3 deaths (SMR 2.87, CI 0.6-8.4), respectively. These findings of excess melanoma and brain cancer mortality confirm 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.
Avima Ruder, Ph.D., National Institute for Occupational Safety and Health, Mailstop R-16, 4676 Columbia Parkway, Cincinnati, OH 45226, USA