Ming-Chieh Li1, Hung-Pin Wu2, Chiu-Yueh Yang3, Pau-Chung Chen4, George H Lambert5, Yue Leon Guo6. 1. Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei, Taiwan; Graduate Institute of Law and Interdisciplinary Studies, National Chengchi University College of Law, Taipei, Taiwan. 2. Department of Otolaryngology, Buddhist Tzuchi General Hospital, Taichung Branch, Taichung, Taiwan; School of Medicine, Tzuchi University, Hualien, Taiwan; Department of Otolaryngology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan. 3. Department of Health Business Administration, Hung-Kuang University, Taichung, Taiwan. 4. Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei, Taiwan; Department of Environmental and Occupational Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. 5. Retired Director NIH/NIEH Children Center, Rutgers, The State University of New Jersey, USA. 6. Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University College of Public Health, Taipei, Taiwan; Department of Environmental and Occupational Medicine, National Taiwan University College of Medicine and National Taiwan University Hospital, Taipei, Taiwan. Electronic address: leonguo@ntu.edu.tw.
Abstract
INTRODUCTION: In 1979, approximately 2000 people in central Taiwan were exposed to polychlorinated biphenyls and dibenzofurans (PCBs/PCDFs) due to ingestion of contaminated rice oil. The children born to mothers exposed to PCBs/PCDFs were called Yucheng children. We conducted a follow-up study to examine the association between gestational PCBs/PCDFS exposure and auditory function in Yucheng children's early adulthood. METHODS: In 1985 and early 1992, Yucheng children and their age, gender, socio-economic matched unexposed referent children were recruited for physical examination and long-term follow-ups. In 2007, Yucheng children and referent children were invited to participate in a health examination, including assessment of pure-tone air-conduction thresholds and distortion product otoacoustic emissions (DPOAEs) test. Gestational exposure to PCBs/PCDFs in Yucheng children were estimated by back-extrapolation of their mother's serum concentration to the time of childbirth. RESULTS: A total of 86 Yucheng children (51.2% males) and 97 referent children (50.5% males) were included for analysis. No difference was found in demographic characteristics between two groups. Among the Yucheng children, 53 had estimated PCBs/PCDFs concentrations. We found that Yucheng children were at higher risk of having elevated hearing threshold at low frequencies in the right ear. Estimated maternal concentrations of 2,3,4,7,8-pnCDF at the time of birth were associated with increased hearing thresholds and decreased DPOAEs amplitudes at low frequencies in the right ear. CONCLUSION: Gestational exposure to PCBs/PCDFs caused adverse asymmetrical hearing effects detectable even in early adulthood.
INTRODUCTION: In 1979, approximately 2000 people in central Taiwan were exposed to polychlorinated biphenyls and dibenzofurans (PCBs/PCDFs) due to ingestion of contaminated rice oil. The children born to mothers exposed to PCBs/PCDFs were called Yucheng children. We conducted a follow-up study to examine the association between gestational PCBs/PCDFS exposure and auditory function in Yucheng children's early adulthood. METHODS: In 1985 and early 1992, Yucheng children and their age, gender, socio-economic matched unexposed referent children were recruited for physical examination and long-term follow-ups. In 2007, Yucheng children and referent children were invited to participate in a health examination, including assessment of pure-tone air-conduction thresholds and distortion product otoacoustic emissions (DPOAEs) test. Gestational exposure to PCBs/PCDFs in Yucheng children were estimated by back-extrapolation of their mother's serum concentration to the time of childbirth. RESULTS: A total of 86 Yucheng children (51.2% males) and 97 referent children (50.5% males) were included for analysis. No difference was found in demographic characteristics between two groups. Among the Yucheng children, 53 had estimated PCBs/PCDFs concentrations. We found that Yucheng children were at higher risk of having elevated hearing threshold at low frequencies in the right ear. Estimated maternal concentrations of 2,3,4,7,8-pnCDF at the time of birth were associated with increased hearing thresholds and decreased DPOAEs amplitudes at low frequencies in the right ear. CONCLUSION: Gestational exposure to PCBs/PCDFs caused adverse asymmetrical hearing effects detectable even in early adulthood.