Increased Urinary Phthalate Levels in Women with Uterine Leiomyoma: A Case-Control Study

We assessed the urinary concentration of 16 phthalate metabolites in 57 women with and without uterine leiomyoma (n = 30 and 27; respectively) to determine the association between phthalate exposure and uterine leiomyoma. To evaluate exposure to di-(2-ethylhexyl) phthalate (DEHP); we calculated the molar sum of DEHP metabolites; ∑3-DEHP (combining mono-(2-ethylhexyl) phthalate (MEHP); mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP); and mono-(2-ethyl-5-oxohexyl) phthalate); ∑4-DEHP (∑3-DEHP plus mono-(2-ethyl-5-carboxypentyl) phthalate); and ∑5-DEHP (∑4-DEHP plus mono (2-(carboxylmethyl)hexyl) phthalate (2cx-MMHP)). The log transformed urinary levels of MEHP; MEHHP; 2cx-MMHP; ∑3-DEHP; ∑4-DEHP; and ∑5-DEHP in the leiomyoma group were significantly higher than those of controls. When we adjusted for age; waist circumference; and parity using multiple logistic regression analyses; we found log ∑3-DEHP (OR = 10.82; 95% CI = 1.25; 93.46) and ∑4-DEHP (OR = 8.78; 95% CI = 1.03; 75.29) were significantly associated with uterine leiomyoma. Our findings suggest an association between phthalate exposure and uterine leiomyoma. However; larger studies are needed to investigate potential interactions between phthalate exposure and uterine leiomyoma.