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Published on: August 29, 2014
Evidence of an age-related threshold effect of polychlorinated biphenyls (PCBs) on neuropsychological functioning in
Richard F Haase1, Robert J McCaffrey, Azara L Santiago-Rivera
1Division of Counseling Psychology, Department of Educational and Counseling Psychology, University at Albany, State University of New York, ED 220, 1400 Washington Avenue, Albany, NY 12222, USA. rfh64@albany.edu
Insights
Polychlorinated biphenyls (PCBs) exposure may impact adult cognitive function, particularly in those over 40. A threshold of 2 ppb revealed adverse effects on memory and executive functioning in Native American adults.
Area of Science:
- Environmental Health
- Neurotoxicology
- Occupational Health
Background:
- Polychlorinated biphenyls (PCBs) are persistent environmental pollutants with suspected adverse effects on human neuropsychological functioning.
- While PCB effects on children's cognition are documented, adult impacts remain less understood.
- Environmental PCB contamination in the St. Lawrence region provides a unique study population.
Purpose of the Study:
- To investigate the relationship between PCB body burden and neuropsychological functioning in Native American adults.
- To identify potential threshold effects and age-related differences in PCB neurotoxicity.
Main Methods:
- Neuropsychological evaluation of 277 Native American adults (ages 18-79) using 18 tests.
- Estimation of PCB body burden through 101 PCB congeners.
- Analysis using spline regression models, adjusting for age, gender, and education.
Main Results:
- A threshold effect for PCBs was observed at approximately 2 ppb.
- An age-by-PCB interaction indicated that the threshold effect was primarily present in adults aged 40-79.
- Memory, motor function, and higher-order executive functioning showed significant associations with PCB levels in older adults.
Conclusions:
- PCB exposure poses a risk to neuropsychological functioning in adults, particularly those over 40.
- The findings suggest a clinically meaningful impact of PCBs on cognitive health in contaminated populations.
- Further research is warranted to understand the long-term implications and clinical management of PCB-related neurotoxicity.
Abstract:
Polychlorinated biphenyls (PCBs) have been suspected for some time of having adverse effects on neuropsychological functioning in humans. While there is evidence of slowing of cognitive function in children associated with exposure to PCBs, the evidence of comparable effects on adults is far less well understood. We report here on the neuropsychological evaluation of 277 Native American adults, ranging in age from 18 to 79, who were exposed to PCBs by way of environmental contamination in the St. Lawrence region of upstate New York. PCB body burden was estimated by 101 PCB congeners and neuropsychological functioning was assessed by a battery of 18 tests. Spline regression models were fitted to the latent variables of memory, motor function, and higher-order executive functioning. After adjusting for age, gender, and education the analyses revealed a threshold effect of PCBs at approximately 2 ppb. An age-by-PCB interaction effect was also observed for several variables which suggests that the threshold effect was largely confined to the age range of 40-79 and was not observable in the 18-40-year-old group. Implications of these results are discussed in comparison to previously published similar work with adults and in terms of its potential clinical meaningfulness.
