Fertil Steril August 15, 2005 First Study Links Dioxin Exposure to Endometriosis in Humans Increased dioxin-like compounds in the serum of women with peritoneal endometriosis and deep endometriotic (adenomyotic) nodules. Heilier JF, Nackers F, Verougstraete V, Tonglet R, Lison D, Donnez J. Industrial Toxicology and Occupational Medicine Unit, Universite Catholique de Louvain, Brussels, Belgium. OBJECTIVE: To investigate the possible association between the body burden of dioxin-like compounds and endometriotic disease. DESIGN: Case-control study. SETTING: Gynecology ward in a university hospital. PATIENT(S): Seventy-one women with peritoneal endometriosis (n = 25) or deep endometriotic (adenomyotic) nodules (n = 25) and controls (n = 21). INTERVENTION(S): Collection of 200 mL of blood (fasted) and face- to-face interview. MAIN OUTCOME MEASURE(S): Assessment of dioxin (PCDD), furan (PCDF), and dioxin-like PCB serum concentrations (picograms toxic equivalent [TEQ]/g lipids). RESULT(S): Age and body mass index were traced by linear multiple regression as determinants of total TEQ levels. After standardization for these variables (30 years and 22.5 kg/m2), the mean TEQ levels were 24.21 (controls), 30.62 (peritoneal endometriosis), and 37.60 (deep endometriotic [adenomyotic] nodules) pg TEQ/g lipids. Logistic regressionanalysis indicated a significantly increased risk of deep endometriotic (adenomyotic) nodules (odds ratio [OR], 3.3; 95% confidence interval [CI], 1.4-7.6) for an increment of 10 pg in total TEQ levels/g lipids. An increased risk was also found for peritoneal endometriosis (OR, 1.9; 95% CI, 0.9-3.8) for total TEQ levels and for dioxins alone (OR, 3.2; 95% CI, 1.0-9.9). CONCLUSION(S): The results provide the first epidemiological evidence of an association between increased PCDD/PCDF and PCB body burden and endometriosis.