title: Age at menarche and metabolic markers for type 2 diabetes in premenopausal women: the BioCycle Study.
abstract: BACKGROUND
  Early age at menarche has been linked to an elevated risk of type 2 diabetes. However, the underlying mechanism is unclear.
  
  
  OBJECTIVE
  Our objective was to examine associations between age at menarche and type 2 diabetes risk factors.
  
  
  METHODS
  The BioCycle Study followed 253 healthy premenopausal women from the general population (Buffalo, NY) for one to two menstrual cycles.
  
  
  METHODS
  Age at menarche was self-reported. Body mass index and waist circumference were measured by trained personnel. Total body and trunk fat were measured by dual-energy x-ray absorptiometry. Fasting glucose, insulin, highly sensitive C-reactive protein, and SHBG levels were measured up to eight times per cycle. Insulin resistance (IR) and β-cell function were evaluated using the homeostasis model assessment (HOMA)-IR and HOMA-β.
  
  
  RESULTS
  The mean age at menarche was 12.5 ± 1.2 yr. After adjustment for age, race, education, and physical activity, early menarche (≤12 yr) was significantly associated with an increase of 1.35 kg/m(2) in body mass index (P = 0.01), 2.52% in percent total body fat (P = 0.004), 3.02% in percent trunk fat (P = 0.004), 0.15 μIU/ml in (log)insulin (P = 0.02), 0.15 U in (log)HOMA-IR (P = 0.03), and 0.16 U in (log)HOMA-β (P = 0.01) compared with average menarche (12-14 yr). No associations were found for SHBG or highly sensitive C-reactive protein.
  
  
  CONCLUSIONS
  Early onset of menarche is associated with unfavorable metabolic phenotypes compared with average onset of menarche in healthy premenopausal women, including reduced insulin sensitivity and β-cell function and greater total and trunk fat.
authors.affiliation: Department of Epidemiology, School of Public Health, Louisiana State University Health Science Center, New Orleans, Louisiana 70112, USA.
authors.forename: Liwei
authors.initials: L
authors.lastname: Chen
authors.forename: Cuilin
authors.initials: C
authors.lastname: Zhang
authors.forename: Edwina
authors.initials: E
authors.lastname: Yeung
authors.forename: Aijun
authors.initials: A
authors.lastname: Ye
authors.forename: Sunni L
authors.initials: SL
authors.lastname: Mumford
authors.forename: Jean
authors.initials: J
authors.lastname: Wactawski-Wende
authors.forename: Enrique F
authors.initials: EF
authors.lastname: Schisterman
mesh_terms: D050154:Adiposity / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D002648:Child; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D005260:Female; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology; D008572:Menarche / Q000378:metabolism*; D017697:Premenopause / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D001786:Blood Glucose