Motor function in aging Great Lakes fisheaters

Exposure to contaminants in Great Lakes fish has been linked to impaired neuropsychological functioning in children, but neurological function of exposed adults has not been evaluated. This report describes a cross- sectional analysis of the effects of PCB/DDE exposure from contaminated fish on fine motor function in older adults. The subjects were 50-90-year-old Michigan residents who were members of a previously established study cohort. Fisheaters ate 24 lbs or more of sport-caught Lake Michigan fish/year at the time they were originally recruited in 1980-1982. Age- and sex-matched nonfisheaters ate 6 or fewer lbs/year. Outcome measures were scores on the Static Motor Steadiness Test (SMST) and Grooved Pegboard Test (GPT). PCB/DDE exposure was determined through serum analyses performed at the time of recruitment into the present study in 1993-1995. Because of the high correlation between serum PCB and DDE levels in this sample (Spearman r = 0.64, P < 0.0001), the effects of the two contaminants were assessed jointly using a single derived exposure variable: Low = both PCB and DDE at or below the medians of their respective distributions, intermediate = PCB and/or DDE in the third quartile, and high = PCB and/or DDE in the upper quartile. In unadjusted analyses, high exposure to PCBs/DDE was associated with significantly poorer performance on the GPT (P = 0.03). However, in the multiple regression model, age and gender emerged as the most significant factors affecting GPT scores, and exposure to PCB/DDE was not significant. Performance on the SMST was not related to PCB/DDE exposure in initial unadjusted analyses, but performance with the dominant hand was marginally (P=0.052) associated with exposure in the final model. Scores on the SMST improved slightly as PCB/DDE exposure increased. A similar trend was not observed for the nondominant hand (P = 0.46). These findings suggest that PCB/DDE exposure from Great Lakes fish has not significantly impaired hand steadiness or visual-motor coordination in this sample of older adults.