Neurological signs and symptoms in patients with chronic PCB poisoning (Yusho accident) for more than 36 years

摘要

The existence of peripheral neuropathy after chronic exposure to polychlorinated biphenyls (PCBs) is still controversial because studies concerning the effects of PCBs on the peripheral nervous system are rare.The purpose of this study was to determine the correlation between neurological signs and symptoms and the concentration of serum PCBs.Neurological data collected from the results of a nationwide health examination of 450 male and 557 female Yusho victims (chronic PCB poisoning) exposed more than 36 years ago were compared with recent measurements of the serum PCB concentration and patterns.The frequency of sensory disturbance detected by neurological examination was significantly higher in the group of officially acknowledged victims (male,P=0.014; female, P=0.001) than in age-matched controls.Significant differences were not observed between the serum PCB patterns and the neurological findings, but the serum PCB concentration was significantly higher in the group with decreased tendon reflex in officially and non-officially acknowledged female Yusho victims (male,P=0.994;female,P=0.014).These results suggest that the long half-life of PCBs and their accumulation in fatty tissue can lead to persistent mild impairment of the peripheral nervous system even long after exposure.