title: High serum isoflavone concentrations are associated with the risk of precocious puberty in Korean girls.
abstract: OBJECTIVE
  The gradual decrease in the age of onset of puberty raises concerns about the contribution of phytoestrogen intake on sexual maturation. However, no data are available on the association between serum isoflavone (genistein, daidzein) concentration and central precocious puberty (CPP). The aim of the study was to test the association between serum isoflavone concentrations and the risk of CPP in Korean girls.
  
  
  METHODS
  A case-control study was conducted at Inje University Hospital in Korea. One-hundred and eight girls with CPP (aged 8·6 ± 0·8 year) and 91 age-matched controls (aged 8·5 ± 0·8 year) were examined.
  
  
  RESULTS
  Serum concentrations of daidzein (P = 0·0202), genistein (P = 0·0021) and total isoflavones (P = 0·0009) were higher in children with CPP than in normal children. When the children were categorized into three groups according to total serum isoflavone as follows: <30, 30-70 and ≥70 nmol/l, serum concentrations of daidzein, genistein and total isoflavones significantly increased across three categories of serum isoflavone (P < 0·0001). The prevalence of CPP was significantly higher in children with serum isoflavone level of ≥30 nmol/l than those with serum level of <30 nmol/l (P = 0·0008). The adjusted OR for precocious puberty increased significantly across a range of total serum isoflavone (OR = 4·39; 95% CI: 1·83-10·51 vs OR = 5·22; 95% CI: 2·07-13·20; P = 0·001).
  
  
  CONCLUSIONS
  These results suggest that elevated serum isoflavones may be associated with the risk of CPP in Korean girls.
authors.affiliation: Department of Food and Nutrition, Daegu University, Gyeongsan, Korea.
authors.forename: Jihye
authors.initials: J
authors.lastname: Kim
authors.forename: Shinhye
authors.initials: S
authors.lastname: Kim
authors.forename: Kyoung
authors.initials: K
authors.lastname: Huh
authors.forename: Yunje
authors.initials: Y
authors.lastname: Kim
authors.forename: Hyojee
authors.initials: H
authors.lastname: Joung
authors.forename: Mijung
authors.initials: M
authors.lastname: Park
mesh_terms: D044466:Asian People / Q000706:statistics & numerical data; D001774:Blood Chemical Analysis; D016022:Case-Control Studies; D002648:Child; D003940:Diagnostic Techniques, Endocrine; D005260:Female; D019833:Genistein / Q000009:adverse effects / Q000097:blood; D006801:Humans; D007529:Isoflavones / Q000009:adverse effects / Q000032:analysis / Q000097:blood*; D007723:Korea; D009994:Osmolar Concentration; D011629:Puberty, Precocious / Q000097:blood / Q000175:diagnosis / Q000208:ethnology / Q000209:etiology*; D012307:Risk Factors
chemical_list: D007529:Isoflavones; C004742:daidzein; D019833:Genistein