Germaine M. Buck Louis, Zhen Chen, C. Matthew. Peterson, Mary L. Hediger, Mary S. Croughan, Rajeshwari Sundaram, Joseph B. Stanford, Michael W. Varner, Victor Y. Fujimoto, Linda C. Giudice, Ann Trumble, Patrick J. Parsons, Kurunthachalam Kannan
Objectives: To assess the association between POPs and odds of an endometriosis diagnosis and the consistency of findings by biologic media and study cohort.
Methods: Using a matched cohort design, we assembled an operative cohort of women aged 18-44 years undergoing laparoscopy or laparotomy at 14 participating clinical centers during 2007-2009, and a population-based cohort matched on age and residence within clinical centers' 50-mile catchment area. Endometriosis was defined as visualized disease in the operative cohort and as magnetic resonance imaging-diagnosed in the population cohort. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each POP in relation to an endometriosis diagnosis, with separate models run for each media (omental fat in the operative cohort; serum in both cohorts) and cohort. Adjusted models included age, body mass index, breastfeeding conditional on parity, cotinine, lipids, and remaining chemicals.
Results: Concentrations were higher in omental fat than serum for all POPs. In the operative cohort, gamma-hexachlorocyclohexane was the only POP with a significant positive association with endometriosis (AOR=1.27; 95% CI=1.01, 1.59 per 1-standard deviation increase in log-transformed γ-HCH); beta-hexachlorocyclohexane was the only significant predictor in the population cohort (AOR=1.72; 95% CI=1.09, 2.72 per 1-standard deviation increase in log-tranformed β-HCH).
Conclusions: Using a matched cohort design, cohort- and biologic media-specific POPs were associated with endometriosis underscoring the importance of methodologic considerations when interpreting findings.
Citation: Buck Louis GM, Chen Z, Peterson CM, Hediger ML, Croughan MS, Sundaram R, et al. 2012. Persistent Lipophilic Environmental Chemicals and Endometriosis: The ENDO Study. Environ Health Perspect :-. http://dx.doi.org/10.1289/ehp.1104432