Effect of occupational polychlorinated biphenyls exposure on quality-adjusted life years over time at the HELPcB surveillance program.

HELPcB (Health Effects in High-Level Exposure to Polychlorinated Biphenyls [PCB]) is a surveillance program for former PCB-exposed workers of a capacitor recycling company and other concerned individuals. The aim of this study was to examine the influence of polychlorinated biphenyls (PCB) on the health-related quality of life (HRQL) and on quality-adjusted life years (QALY). The EQ-5D-3L questionnaire was used to determine the HRQL. After three cross-sectional examinations at intervals of 1 yr, the longitudinal development of QALY was compared by repeated-measurement analysis of covariance (ANCOVA). The cohort was split at the 95th percentile of the comparison group for each PCB congener; known confounders such as age were taken into account. A significant difference in height and development of QALY over time was shown for the higher chlorinated non-dioxin-like PCB (hcPCB) congeners. A significant between-groups effect was found on PCB 153, PCB 180, and the sum of hcPCB. It was found that QALY decreased in the high-burden group and QALY stabilized after yr 2 in the normal-burden group. Taking the dimensions of the EQ-5D into account, the between-groups effect seems to be based predominantly on the dimension anxiety. The development of the within-group effect, however, seems to be based on the dimension mobility. This study detected a significant influence of hcPCB on the development of HRQL and QALYs over time according to the level of internal PCB burden.

Neuropsychological effects of occupational exposure to polychlorinated biphenyls.

In the context of a health surveillance program for former PCB-exposed workers of a transformer and capacitor recycling company in Germany, their family members, employees of surrounding companies and area residents a broad range of cognitive functions covering attention, executive processing, reasoning, memory and motor performance was examined. The study aimed at identifying potential adverse effects of PCB load on cognitive functions. Detailed analysis of PCB burden of the participants revealed rather high correlations of lower and higher chlorinated as well as dioxin-like PCBs. Nearly one half of the participants exhibited increased burden in all three PCB classes whereas only 33 out of 237 participants did not show any increased PCB burden. Thus, data analysis followed a two-fold strategy: (1) Based on studies providing data on PCB exposure of the German general population the PCB burden of every participant was classified as normal (percentile rank PR <95) or increased (PR ≥95). Increased burden with respect to lower (LPCBs) and higher chlorinated (HPCBs) as well as dioxin-like (dlPCBs) PCBs was assumed if a participant showed at least one congener surpassing the PR95 criterion for the respective congener class and (2) Overall plasma PCB level per congener class was used as measure of PCB load. In a multivariate approach using structural equation modelling and multiple regression analysis we found a significant impact of PCBs on word fluency and sensorimotor processing irrespective of the measure of PCB burden (PR95 criterion or overall plasma level). However, no effect of PCB burden on memory, attention, and cognitive flexibility could be demonstrated. Particularly, an increase of LPCBs was associated with an overall reduction of verbal fluency of letter and semantic word generation as well as word production based on a single or two alternating criteria. In addition, participants with increased burden of LPCBs exhibited a time-on-task effect in terms of a stronger decline of performance with increasing duration of the verbal fluency task. Moreover, we found adverse effects of HPCBs on Aiming and of dlPCBs on Line Tracking. Results are discussed in terms of (1) a decrease of cerebral dopamine (DA) with non-coplanar PCBs resulting in an impact on fronto-striatal cerebral structures subserving verbal fluency and motor processing, (2) a PCB-induced reduction of norepinephrine leading to the time-on-task effect with verbal fluency, and (3) adverse effects of PCBs on dopaminergic receptors in the cerebellum resulting in impaired fine motor function.