title: Exposure to a mixture of polychlorinated biphenyls and polychlorinated dibenzofurans resulted in a prolonged time to pregnancy in women.
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 non-contraceptive 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.
authors.affiliation: The Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan, Taiwan.
authors.forename: Chiu-Yueh
authors.initials: CY
authors.lastname: Yang
authors.forename: Ying-Jan
authors.initials: YJ
authors.lastname: Wang
authors.forename: Pau-Chung
authors.initials: PC
authors.lastname: Chen
authors.forename: Shaw-Jenq
authors.initials: SJ
authors.lastname: Tsai
authors.forename: Yueliang Leon
authors.initials: YL
authors.lastname: Guo
mesh_terms: D000328:Adult; D001572:Benzofurans / Q000378:metabolism*; D000072338:Dibenzofurans, Polychlorinated; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D005298:Fertility / Q000187:drug effects; D006801:Humans; D007247:Infertility, Female / Q000139:chemically induced*; D007407:Interviews as Topic; D008297:Male; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D011247:Pregnancy; D016016:Proportional Hazards Models; D016019:Survival Analysis; D013624:Taiwan; D013997:Time Factors
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D011078:Polychlorinated Biphenyls