Ratio of serum to adipose levels of persistent endocrine disrupting chemicals in relation to endometriosis

OPS 16: Chemical exposures and birth outcomes, Room 114, Floor 1, August 28, 2019, 10:30 AM - 12:00 PM Background/Aim: Endometriosis is an estrogen-dependent disease and endocrine disrupting chemicals (EDCs) seem to play a role in its etiology. The ratio of circulating versus stored levels of persistent organic pollutants (POPs) may offer new insight as it combines serum levels, which reflect current exposure and release from internal storage, together with adipose levels, which reflect long-term exposure and storage. Methods: This study quantified 12 organochlorine pesticides, 6 polybrominated diphenyl ether (PBDE) congeners, and 35 polychlorinated biphenyl (PCB) congeners in both serum and omental fat in women aged 18-44 with (n=190) and without (n=283) incident surgically visualized endometriosis. Participants were recruited from clinical centers in Salt Lake City and San Francisco (2007-2009). Logistic regression adjusting for age and body mass index was conducted. The circulating/stored log transformed chemical ratio was modeled separately for each chemical and together using principal component analysis (PCA). Results: The ratio of serum to adipose of sum PBDEs and PCB 74 were associated with endometriosis (OR=1.24, 95% CI: 1.02, 1.52, OR=1.16, 95% CI: 1.02, 1.32). The ratio of serum to adipose for PBDE 183, oxychlordane, gamma-hexachlorocyclohexane (HCH) and beta-HCH were associated with a decreased odds of endometriosis. When using PCA, multichemical factors of the circulating to stored chemical ratio were not associated with endometriosis. Conclusions: These findings differ from results evaluating serum and adipose tissue separately. This approach may offer novel insights on the relationship between persistent organic pollutants and endometriosis. Because lipid metabolism may be perturbed in endometriotic phenotypes, measurement of POPs from serum and adipose tissue separately could be less than an ideal characterization of exposure, thus underscoring the importance of evaluating exposure using this type of novel approach.