Systematic Review of the Epidemiologic Study Quality on Polychlorinated Biphenyls and Endometriosis

Introduction: Polychlorinated biphenyls (PCBs) are a class of persistent organic pollutants found in the environment. Endometriosis, an estrogen-dependent gynecological disease, affects about 15% of women of reproductive age. Previous studies have suggested associations between PCB levels and occurrence of endometriosis. Aim: To systematically evaluate the available epidemiologic literature investigating potential associations between PCB exposure and the occurrence of endometriosis. Methods: We did a title and abstract search searched for literature containing using specific search terms, including “endometriosis” and common or trade names for PCBs. After an initial screen, studies identified for potential inclusion underwent a full review examining study quality and risk of bias. Results: The literature search and review identified 41 human studies. After further review, 21 relevant epidemiologic studies were identified with analyses of associations between PCB exposure and endometriosis. Of these, 9 papers reported positive associations and 12 reported null results. Study quality was generally good or adequate, and risk of bias was low. Most studies (71%) based their exposure assessment on lipid-adjusted PCB concentrations in serum samples. Additionally, 17 (81%) studies used the optimal outcome assessment of laparoscopy to confirm endometriosis in study participants. Conclusions: Study variations were identified for the literature on the potential associations between PCB exposure and the occurrence of endometriosis. These variations included inconsistencies in the PCB congeners measured, type of biological samples measured, and manipulation of data for analyses. Considering these differences, direct comparisons across studies were difficult if not impossible. Disclaimer: The views expressed in this abstract are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.