Persistent organic pollutants (POPs) and fibroids: results from the ENDO study

To evaluate the association between persistent organic pollutants (POPs) and uterine fibroids, we used previously collected data from a cohort of women aged 18-44 years undergoing laparoscopy or laparotomy at 14 participating hospital surgical centers (n=473). POP concentrations were measured in omental fat and serum. Presence of fibroids was defined on the basis of a postoperative diagnosis (n=99). Odds ratios (OR) and 95% confidence interval (CI) for each POP by biologic medium were estimated using unconditional logistic regression adjusted for identified covariates. Concentrations were higher in omental fat than in serum for all POPs. Serum p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) was the only POP associated with fibroids (per 1-SD increase in log-transformed p,p'-DDE OR (95% CI): 1.37 (1.05-1.80)). In analyses excluding women diagnosed with endometriosis, a number of polychlorinated biphenyls (PCBs) measured in omental fat were associated with fibroids (PCB 99: 1.64 (1.08, 2.49); PCB 138: 1.64 (1.03, 2.59); PCB 146: 1.54 (1.01, 2.37); PCB 153: 1.88 (1.12, 3.13); PCB 196: 1.60 (1.02, 2.51); PCB 206: 1.52 (1.01, 2.29)). Although exploratory, our study suggests that PCBs may be associated with fibroids in the absence of other gynecologic disorders such as endometriosis, but the associations varied by biologic media with more POPs emerging when quantified in fat.