| Exposure to a Mixture of Polychlorinated Biphenyls and Polychlorinated Dibenzofurans Resulted in a Prolonged Time to Pregnancy in Women Chiu-Yueh Yang,1,2 Ying-Jan Wang,3 Pau-Chung Chen,4 Shaw-Jenq Tsai,1,5 and Yueliang Leon Guo4,6 1The Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan; 2Department of Health Business Administration, Hung-Kuang University, Taichung, Taiwan; 3Department of Environmental and Occupational Health, National Cheng Kung University Medical College, Tainan, Taiwan; 4Department of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei, Taiwan; 5Department of Physiology, National Cheng Kung University Medical College, Tainan, Taiwan; 6Department of Environmental and Occupational Medicine, National Taiwan University (NTU) and NTU Hospital, Taipei, Taiwan Abstract
Background: Polychlorinated biphenyls (PCBs) , dibenzofurans (PCDFs) , and dibenzodioxins (PCDDs) may affect the female reproductive system in animals and humans. In 1978–1979, a mass poisoning occurred in central Taiwan due to PCB/PCDF-contaminated cooking oil ; this incident was called Yucheng ("oil disease" in Chinese) . Objective: The purpose of our study was to determine whether PCB/PCDF exposure affected fertility in exposed women. Methods: After the event, we followed the exposed individuals and a reference group who were sex-, age-, and community-matched. In 2003, we obtained fertility histories from Yucheng and reference women by telephone interview. We used Kaplan–Meier survival curves and multivariable Cox regression to compare time to pregnancy (TTP) between Yucheng and reference women, and we performed multiple logistic regression to determine whether PCB/PCDF exposure caused infertility. Results: In total, 412 women responded, with a median TTP of 4 months in Yucheng women and 3 months in reference women (p = 0.019) . After adjusting for confounders by Cox regression, we found a fecundability ratio of 0.90 [95% confidence interval (CI) , 0.80–1.00] for Yucheng women. Among the 408 women who had noncontraceptive sexual activity for > 12 months, 19.7% of Yucheng women and 9.7% of reference women did not become pregnant (i.e., they were infertile) . After we adjusted for confounders by logistic regression, the infertility odds ratio was 2.34 (95% CI, 1.23–4.59) for Yucheng women compared with the reference group. Conclusions: We found prolonged TTP and reduced fertility among women previously exposed to PCBs/PCDFs. Because of the limited sample size and the relatively small decrease in the fertility rate, these effects require cautious interpretation and further investigation for confirmation. Key words: fertility, infertility, PCBs, PCDFs, polychlorinated biphenyls, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, pregnancy, reproduction, time to pregnancy. Environ Health Perspect 116:599–604 (2008) . doi:10.1289/ehp.10715 available via http://dx.doi.org/ [Online 24 January 2008]
Address correspondence to Y.L. Guo, Department of Environmental and Occupational Medicine, National Taiwan University (NTU) and NTU Hospital, 17, Syujhou Rd., Taipei 100, Taiwan, ROC. Telephone: 886-2-33228216. Fax: 886-2-33228214. E-mail: leonguo@ntu.edu.tw This study was funded by grant NSC95-2621-Z-002-030 from the National Science Council of Taiwan. The authors declare they have no competing financial interests. Received 27 July 2007 ; accepted 22 January 2008.
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