213 Environmental Contaminants and Dietary Factors in Endometriosis WARREN G. FOSTER AND SANJAY K. AGARWAL Department of Obstetrics and Gynecology, Cedars-Sinai Medical Center, Los Angeles, California, USA ABSTRACT: Endometriosis is an estrogen-dependent disease characterized by the presence of endometrial glands and stroma outside the uterine cavity. The etiology of this disease remains elusive, but is clearly influenced by genetic, immune, and endocrine factors. Exposure to environmental contaminants has recently been added to the list of potential factors that contribute to the patho- genesis of endometriosis. The objective of this paper is to review the weight of the evidence from hospital-based case-control studies and animal experiments for an association between exposure to environmental contaminants and endometriosis. KEYWORDS: endometriosis; animal models; toxicology; monkeys; TCDD INTRODUCTION Endometriosis is an estrogen-dependent disease characterized by the presence of endometrial glands and stroma outside the uterine cavity. The etiology of this disease remains elusive, but is clearly influenced by genetic, immune, and endocrine factors. Retrograde menstruation or bleeding into the peritoneal cavity during menstruation is widely accepted as a major contributing factor in the pathogenesis of this disease. However, backflow of menstrual materials through the fallopian tubes to the pelvic cavity is a common phenomenon even in women without endometriosis. 1 Hence, factors other than retrograde menstruation such as hormonal stimulation or impaired immune function are thought to contribute to the development and progression of endometriosis. Exposure to environmental contaminants has recently been added to the list of potential factors that contribute to the pathogenesis of endometriosis. This view is supported by a number of lines of evidence. Specifically, exposure to various environmental contaminants has been demonstrated through the detection of chemical contaminants in the serum and ovarian follicular fluid of women attending fertility clinics. 2 Further, estrogenic activity for numerous environmental contami- nants, together with the estrogen dependence of endometriosis, leads us to speculate that environmental contaminants can play a role in the pathophysiology of endometriosis. The association between exposure to environmental contaminants and endometriosis has previously been reviewed. 3–5 Thus, the objective of this paper Address for correspondence: Warren G. Foster, Ph.D., Director, Reproductive Biology, Depart- ment of Obstetrics and Gynecology, HSC-3N52, McMaster University, 1200 Main Street West, Hamilton, Ontario, Canada L8N 3Z5. Voice: 905-525-9140, ext. 22822; fax: 905-524-2911. fosterw@mcmaster.ca