Research Association of Exposure to Phthalates with Endometriosis and Uterine Leiomyomata: Findings from NHANES, 1999–2004

Ba c k g r o u n d: Phthalates are ubiquitous chemicals used in consumer products. Some phthalates are reproductive toxicants in experimental animals, but human data are limited. Objective: We conducted a cross-sectional study of urinary phthalate metabolite concentrations in relation to self-reported history of endometriosis and uterine leiomyomata among 1,227 women 20–54 years of age from three cycles of the National Health and Nutrition Examination Survey (NHANES), 1999–2004. Met h o d s: We examined four phthalate metabolites: mono(2-ethylhexyl) phthalate (MEHP), monobutyl phthalate (MBP), monoethyl phthalate (MEP), and monobenzyl phthalate (MBzP). From the last two NHANES cycles, we also examined mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP). We used logistic regression to estimate odds ratios (ORs) and 95 % confidence intervals (CIs), adjusting for potential confounders. Res u l t s: Eighty-seven (7%) and 151 (12%) women reported diagnoses of endometriosis and leiomyomata, respectively. The ORs comparing the highest versus lowest three quartiles of urinary MBP were 1.36 (95 % CI, 0.77–2.41) for endometriosis, 1.56 (95 % CI, 0.93–2.61) for leiomyomata, and 1.71 (95 % CI, 1.07–2.75) for both conditions combined. The corresponding ORs for