| Neurocognitive Changes among Elderly
Exposed to PCBs/PCDFs in Taiwan Kao-Chang Lin,1 Nai-Wen Guo,2 Pei-Chien Tsai,3 Chiu-Yueh Yang,3 and YueLiang Leon Guo4,5 1Department
of Neurology, Chi-Mei Medical Center, Tainan, Taiwan; 2Institute
of Behavioral Medicine, and 3Institute of Basic Medical Sciences, National
Chen-Kung University Medical College, Tainan, Taiwan; 4Department
of Environmental and Occupational Medicine, National Taiwan
University College of Medicine, Taipei, Taiwan; 5Department
of Environmental and Occupational Medicine, National Taiwan
University Hospital, Taipei, Taiwan Abstract
Background: In 1979 approximately 2,000 people were exposed to polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs) due to ingestion of contaminated cooking oil in Taiwan. Although a previous study has shown delayed developmental milestones and poorer neurocognitive functioning in children born to exposed mothers, it is unclear whether neurocognitive functioning was impaired in people who were directly exposed to the PCBs and PDCFs. Objective: The objective of this study was to compare neurocognitive functioning in people exposed to PCBs and PCDFs with that of unexposed sex- and age-matched neighbors. Methods: We conducted a retrospective cohort study among exposed and unexposed subjects ≥ 60 years of age using prospective outcome measurements. We evaluated neurocognitive tests including cognition, memory modalities, learning, motor and sensory function, mood, and daily activity. Results: In total, 162 (59%) exposed and 151 (55%) reference subjects completed this study. In exposed men, all test results were similar to the reference group ; however, exposed women had reduced functioning in attention and digit span (ADS) , visual memory span (VMS) , and verbal memory recalls (VMR) , especially learning ability. We also found a borderline reduction in the Mini-Mental State Examination. The digit symbol, motor, sensory, depression (determined by the Geriatric Depression Scale-Short Form) , and activity of daily life were not different between the exposed and reference groups. A significant dose–response relationship was found for VMR, ADS, and VMS. Conclusion: Our study showed dose-dependent neurocognitive deficits in certain aspects of attention, visual memory, and learning ability in women previously exposed to PCBs and PCDFs, but not in exposed men. Key words: elderly, neurocognitive functioning, neuropsychological tests, PCBs, PCDFs, polychlorinated biphenyls, polychlorinated dibenzofurans. Environ Health Perspect 116:184–189 (2008) . doi:10.1289/ehp.10134 available via http://dx.doi.org/ [Online 16 October 2007]
Address correspondence to Y.L. Guo, Department of Environmental and Occupational Medicine, National Taiwan University College of Medicine, Room 339, 17 Syujhou Rd., Taipei 100, Taiwan. Telephone: 886-2-968661310. Fax: 886-2-3322-8214. E-mail: leonguo@ntu.edu.tw This study was funded in part by the National Science Council of Taiwan, ROC (grant NSC94-2314-B-006-073) . The authors declare they have no competing financial interests. Received 2 February 2007 ; accepted 16 October 2007.
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