Effects of prenatal exposure to environmental hormones PCBs/PCDFs on neurocognitive functioning- The pilot study

• Main Authors: Yi-Chieh Huang, 黃亦潔
• Other Authors: Yueliang Leon Guo
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/98693526250259902175

碩士 === 國立臺灣大學 === 職業醫學與工業衛生研究所 === 100 === Background: In 1979, approximately 2000 people in central Taiwan were accidentally exposed polychlorinated biphenyls (PCBs) and dibenzofurans (PCDFs) due to ingest the contaminated rice oil. Children born to exposed mothers after the exposure event were thus prenatally exposed. We followed up these children for health effects and found poorer neurocognitive development. The effect is still presence in the prenatal exposed child after the event about 7~12 years. We would like to know the adult IQ of the prenatal exposed second generation, and assess the neurocognitive effect of second generation comprehensively. The study aim is：1. Whether the dose - effect relationship was found between IQ and predicted PCBs/PCDFs concentration? 2. Whether PCBs/PCDFs exposure could affect the nerve conduction potential situation? 3. Whether PCBs/PCDFs exposure was associated with activation changes in specific brain regions of cortical? Method: The study sample is prenatal exposed people and their matched controls. In the study aim 1, there are 110 prenatal exposed people and 124 matched controls. Assess the relationship between the predicted PCBs/PCDFs concentration and the child IQ. In the study aim 2 and 3, among the 304 prenatal exposed people that we follow up regularly, and the age range from19 to 32 years, we select 10 young men and their matched controls 11 volunteer. We propose to utilize the recently advanced neuroimaging technologies, namely, functional magnetic resonance imaging (fMRI) to examine the functional activations. In addition, Wechsler Adult Intelligence Scale (WAIS) and contact heat evoke potential (CHEP) used to follow the participants’ neurocognitive functioning. Result: Among Yucheng children, males and females were affected rather differently in IQ. Some subscales of WISC-R were negatively related to mothers’ serum levels of PCB congeners 138, 153, 157, and 180. Among adults, Wechsler intelligence scores were lower in Yucheng boys as compared to their controls. The amplitudes of the contact heat evoke potential in legs of Yucheng men was found to be lower than those in the controls (p=0.03). In functional MRI, the parietal activation with picture task (p<0.001) was found in both groups. Yucheng men had higher activation in cerebellum than their controls in the contrast results (p<0.001), and had lower activation in hippocampus, amygdala than their controls (p<0.001). We conclude that IQ was affected in the second generation of Yucheng women. These effects were dose-related to maternal exposure levels. Reduced evoke potential amplitude induced by heat exposure was seen in Yucheng second generation. Using functional activation studies, different regions of activation were seen in Yucheng and their controls. Further studies with larger number of participants are warranted to confirm this finding.