title: Effect of soy isoflavones on endometriosis: interaction with estrogen receptor 2 gene polymorphism.
abstract: BACKGROUND
  Progression of endometriosis is considered estrogen-dependent. Dietary soy isoflavones may affect the risk of endometriosis, and polymorphisms in estrogen receptor genes may modify this association. We examined associations among soy isoflavone intake, estrogen receptor 2 (ESR2) gene polymorphisms and risk of endometriosis.
  
  
  METHODS
  We recruited women age 20-45 years old who had consulted a university hospital for infertility in Tokyo, Japan in 1999 or 2000. A total of 138 eligible women were diagnosed laparoscopically and classified into 3 subgroups: control (no endometriosis), early endometriosis (stage I-II) and advanced endometriosis (stage III-IV). We measured urinary levels of genistein and daidzein as markers for dietary intake of soy isoflavones, and genotyped ESR2 gene RsaI polymorphisms.
  
  
  RESULTS
  Higher levels of urinary genistein and daidzein were associated with decreased risk of advanced endometriosis (P for trend = 0.01 and 0.06, respectively) but not early endometriosis. For advanced endometriosis, the adjusted odds ratio for the highest quartile group was 0.21 (95% confidence interval = 0.06-0.76) for genistein and 0.29 (0.08-1.03) for daidzein, when compared with the lowest group. Inverse associations were also noted between urinary isoflavones and the severity of endometriosis (P for trend = 0.01 for genistein and 0.07 for daidzein). For advanced endometriosis, ESR2 gene RsaI polymorphism appeared to modify the effects of genistein (P for interaction = 0.03).
  
  
  CONCLUSIONS
  Dietary isoflavones may reduce the risk of endometriosis among Japanese women.
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan.
authors.forename: Masaki
authors.initials: M
authors.lastname: Tsuchiya
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Miura
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Hanaoka
authors.forename: Motoki
authors.initials: M
authors.lastname: Iwasaki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sasaki
authors.forename: Tadao
authors.initials: T
authors.lastname: Tanaka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakao
authors.forename: Takahiko
authors.initials: T
authors.lastname: Katoh
authors.forename: Tsuyomu
authors.initials: T
authors.lastname: Ikenoue
authors.forename: Michinori
authors.initials: M
authors.lastname: Kabuto
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
mesh_terms: D000328:Adult; D004032:Diet; D004715:Endometriosis / Q000378:metabolism / Q000517:prevention & control*; D047629:Estrogen Receptor beta / Q000235:genetics*; D005260:Female; D019833:Genistein / Q000652:urine; D006801:Humans; D007529:Isoflavones / Q000008:administration & dosage* / Q000378:metabolism / Q000652:urine; D008875:Middle Aged; D011110:Polymorphism, Genetic; D012306:Risk; D013025:Glycine max
chemical_list: D047629:Estrogen Receptor beta; D007529:Isoflavones; C004742:daidzein; D019833:Genistein