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Our data are limited due to small numbers and reliance on mortality rather than incidence data, but are suggestive of an effect of PCBs on neurodegenerative disease for women. The literature does not offer an explanation for why women would be more affected than men by PCB exposure for these outcomes.

This article describes a systematic review of the industrial hygiene literature for uses of trichloroethylene (TCE) in industry for the exposure assessment of two population-based case control studies of brain cancer in the United States. Papers and reports that address uses of and exposures to TCE were identified from MEDLINE, TOXLINE, NIOSHTIC, the NIOSH Health Hazard Evaluation database (keywords: chlorinated solvents and trichloroethylene), and in other reviews. This search was complemented by reviewing the reference lists from the identified literature. The collected information was systematized by the Standard Industrial Classification (SIC) system, and measurement data reported in the literature were summarized in a database. TCE use was extensive from the early 1920s through the 1970s mainly as a degreasing agent in metal-fabricating operations. After the 1970s it became less popular because of environmental concerns. TCE historically has had a multitude of uses in many other industries, e.g., dry cleaning, textile, electronics, leather, and rubber. Also, many products like adhesives, drugs, paints, inks, and various industrial products have contained TCE. It was banned as a food additive and in cosmetics in 1977. The arithmetic mean (AM) of the measurements across all industries and decades was 38.2 ppm. The highest personal and area air levels were reported in vapor degreasing (AM of 44.6 ppm). Most TCE measurements were performed in the 1950s, 1970s, and 1980s. The data described here could be used by exposure assessors as is to identify the presence and approximate levels of exposure. Using the same information as a basis should increase the reliability of the assessments, making it easier to compare both the exposure assessment methods and the epidemiologic results across different studies.

BackgroundWe expanded an existing cohort of workers (n = 2,588) considered highly exposed to polychlorinated biphenyls (PCBs) at two capacitor manufacturing plants to include all workers with at least 90 days of potential PCB exposure during 1939–1977 (n = 14,458). Causes of death of a priori interest included liver and rectal cancers, previously reported for the original cohort, and non-Hodgkin lymphoma (NHL), melanoma, and breast, brain, intestine, stomach, and prostate cancers, based on other studies.MethodsWe ascertained vital status of the workers through 1998, and cumulative PCB exposure was estimated using a new job exposure matrix. Analyses employed standardized mortality ratios (SMRs; U.S., state, and county referents) and Poisson regression modeling.ResultsMortality from NHL, melanoma, and rectal, breast, and brain cancers were neither in excess nor associated with cumulative exposure. Mortality was not elevated for liver cancer [21 deaths; SMR 0.89; 95% confidence interval (CI), 0.55–1.36], but increased with cumulative exposure (trend p-value = 0.071). Among men, stomach cancer mortality was elevated (24 deaths; SMR 1.53; 95% CI, 0.98–2.28) and increased with cumulative exposure (trend p-value = 0.039). Among women, intestinal cancer mortality was elevated (67 deaths; SMR 1.31; 95% CI, 1.02–1.66), especially in higher cumulative exposure categories, but without a clear trend. Prostate cancer mortality, which was not elevated (34 deaths; SMR 1.04; 95% CI, 0.72–1.45), increased with cumulative exposure (trend p-value = 0.0001).ConclusionsThis study corroborates previous studies showing increased liver cancer mortality, but we cannot clearly associate rectal, stomach, and intestinal cancers with PCB exposure. This is the first PCB cohort showing a strong exposure–response relationship for prostate cancer mortality.