title: Higher levels of IGF-I and adrenal androgens at age 8 years are associated with earlier age at menarche in girls.
abstract: BACKGROUND
  Earlier age at menarche is associated with rapid infancy weight gain and childhood obesity. The role of hormone levels in mediating these associations is unclear.
  
  
  OBJECTIVE
  The aim of this study was to identify childhood hormone levels at age 8 yr that are associated with early menarche, independent of body size.
  
  
  METHODS
  A total of 329 girls from a prospective United Kingdom birth cohort study provided blood samples at mean age 8.1 yr (range, 8.0-8.5) for hormone measurements and were followed longitudinally to establish age at menarche.
  
  
  METHODS
  Fasting plasma levels of IGF-I, androstenedione, dehydroepiandrosterone sulfate (DHEAS), leptin, insulin, IGF binding protein-1, and SHBG were measured. Age at menarche was reported by questionnaire and categorized as before 12.0, 12.0-13.0, or later than 13 yr.
  
  
  RESULTS
  Earlier menarche was associated with greater body weight, height, and body mass index at age 8 yr (all P-trend <0.001). Before adjustment for body size, earlier menarche was associated with higher levels of IGF-I, androstenedione, DHEAS, leptin, and fasting insulin, and with lower levels of IGF binding protein-1 and SHBG at age 8 yr (all P < 0.01). After adjustment for body mass index and height at age 8 yr, only IGF-I (P = 0.004), androstenedione (P = 0.01), and DHEAS (P = 0.01) remained associated with earlier menarche.
  
  
  CONCLUSIONS
  Associations between higher levels of IGF-I and adrenal androgens at age 8 yr with earlier menarche, independent of body size, support functional roles of these hormones in regulating puberty timing in girls. Higher levels of these hormones reported in children who exhibited rapid weight gain during infancy may indicate their role in developmental pathways leading to earlier sexual maturation.
authors.affiliation: Department of Paediatrics, University of Cambridge, Cambridge CB2 0QQ, United Kingdom.
authors.forename: Ajay
authors.initials: A
authors.lastname: Thankamony
authors.forename: Ken K
authors.initials: KK
authors.lastname: Ong
authors.forename: M Lynn
authors.initials: ML
authors.lastname: Ahmed
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Ness
authors.forename: Jeff M P
authors.initials: JM
authors.lastname: Holly
authors.forename: David B
authors.initials: DB
authors.lastname: Dunger
mesh_terms: D000293:Adolescent; D000735:Androstenedione / Q000097:blood*; D002648:Child; D003687:Dehydroepiandrosterone / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D020738:Leptin / Q000097:blood; D008137:Longitudinal Studies; D008572:Menarche / Q000097:blood / Q000502:physiology*; D011446:Prospective Studies; D011627:Puberty / Q000097:blood / Q000502:physiology*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism
chemical_list: D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D020738:Leptin; D012738:Sex Hormone-Binding Globulin; D000735:Androstenedione; D003687:Dehydroepiandrosterone; D007334:Insulin-Like Growth Factor I