title: Adolescent girls with anorexia nervosa have impaired cortical and trabecular microarchitecture and lower estimated bone strength at the distal radius.
abstract: BACKGROUND
  Adolescents with anorexia nervosa (AN) have low areal bone mineral density (aBMD) at both cortical and trabecular sites, and recent data show impaired trabecular microarchitecture independent of aBMD. However, data are lacking regarding both cortical microarchitecture and bone strength assessment by finite element analysis (FEA) in adolescents with AN. Because microarchitectural abnormalities and FEA may predict fracture risk independent of aBMD, these data are important to obtain.
  
  
  OBJECTIVE
  Our objective was to compare both cortical and trabecular bone microarchitecture and FEA estimates of bone strength in adolescent girls with AN vs normal-weight controls.
  
  
  METHODS
  We conducted a cross-sectional study at a clinical research center that included 44 adolescent girls (21 with AN and 23 normal-weight controls) 14 to 22 years old.
  
  
  METHODS
  We evaluated 1) aBMD (dual-energy x-ray absorptiometry) at the distal radius, lumbar spine, and hip, 2) cortical and trabecular microarchitecture at the ultradistal radius (high-resolution peripheral quantitative computed tomography), and 3) FEA-derived estimates of failure load at the ultradistal radius.
  
  
  RESULTS
  aBMD was lower in girls with AN vs controls at the lumbar spine and hip but not at the distal radius. Girls with AN had lower total (P < .0001) and trabecular volumetric BMD (P = .02) and higher cortical porosity (P = .03) and trabecular separation (P = .04). Despite comparable total cross-sectional area, trabecular area was higher in girls with AN (P = .04), and cortical area and thickness were lower (P = .002 and .02, respectively). FEA-estimated failure load was lower in girls with AN (P = .004), even after controlling for distal radius aBMD.
  
  
  CONCLUSIONS
  Both cortical and trabecular microarchitecture are altered in adolescent girls with AN. FEA-estimated failure load is decreased, indicative of reduced bone strength. The finding of reduced cortical bone area in girls with AN is consistent with impaired cortical bone formation at the endosteum as a mechanism underlying these findings.
authors.affiliation: Neuroendocrine Unit, Massachusetts General Hospital for Children, Boston, Massachusetts 02114, USA.
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Faje
authors.forename: Lamya
authors.initials: L
authors.lastname: Karim
authors.forename: Alex
authors.initials: A
authors.lastname: Taylor
authors.forename: Hang
authors.initials: H
authors.lastname: Lee
authors.forename: Karen K
authors.initials: KK
authors.lastname: Miller
authors.forename: Nara
authors.initials: N
authors.lastname: Mendes
authors.forename: Erinne
authors.initials: E
authors.lastname: Meenaghan
authors.forename: Mark A
authors.initials: MA
authors.lastname: Goldstein
authors.forename: Mary L
authors.initials: ML
authors.lastname: Bouxsein
authors.forename: Madhusmita
authors.initials: M
authors.lastname: Misra
authors.forename: Anne
authors.initials: A
authors.lastname: Klibanski
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D041923:Adolescent Development; D000328:Adult; D000856:Anorexia Nervosa / Q000473:pathology* / Q000503:physiopathology; D015992:Body Mass Index; D015519:Bone Density; D001846:Bone Development; D001842:Bone and Bones / Q000737:chemistry / Q000000981:diagnostic imaging / Q000473:pathology*; D001900:Boston / Q000453:epidemiology; D055598:Chemical Phenomena; D003430:Cross-Sectional Studies; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D020342:Finite Element Analysis; D050723:Fractures, Bone / Q000453:epidemiology / Q000209:etiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D016062:Porosity; D012306:Risk; D014057:Tomography, X-Ray Computed; D055815:Young Adult