title: Serum FGF-21 levels are associated with worsened radial trabecular bone microarchitecture and decreased radial bone strength in women with anorexia nervosa.
abstract: BACKGROUND
  Anorexia nervosa (AN) is a psychiatric disorder characterized by self-induced starvation and low body weight. Women with AN have impaired bone formation, low bone mass and an increased risk of fracture. FGF-21 is a hormone secreted by the liver in starvation and FGF-21 transgenic mice have significant bone loss due to an uncoupling of bone resorption and bone formation. We hypothesized that FGF-21 may contribute to the low bone mass state of AN.
  
  
  METHODS
  We studied 46 women: 20 with AN (median age [interquartile range]: 27.5 [25, 30.75] years) and 26 normal-weight controls (NWC) of similar age (25 [24, 28.5] years). We investigated associations between serum FGF-21 and 1) aBMD measured by dual energy X-ray absorptiometry, 2) parameters of bone microarchitecture in the distal radius and tibia measured by high-resolution peripheral quantitative CT and 3) bone strength, estimated by microfinite element analysis.
  
  
  RESULTS
  FGF-21 levels were similar in AN and NWC (AN: 33.1 [18.1, 117.0] pg/ml vs. NWC: 57.4 [23.8, 107.1] pg/ml; p = 0.54). There was a significant inverse association between log FGF-21 and trabecular number in the radius in both AN (R = -0.57, p < 0.01) and NWC (R=-0.53, p < 0.01) and a significant positive association between log FGF-21 and trabecular separation in the radius in AN (R = 0.50, p < 0.03) and NWC (R = 0.52, p < 0.01). Estimates of radial bone strength were inversely associated with log FGF-21 in AN (R = -0.50, p < 0.03 for both stiffness and failure load). There were no associations between FGF-21 and aBMD, cortical parameters or tibial parameters in the AN or NWC groups.
  
  
  CONCLUSIONS
  FGF-21 may be an important determinant of trabecular skeletal homeostasis in AN.
authors: Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA. Electronic address: pkfazeli@partners.org.
authors: Pouneh K
authors: PK
authors: Fazeli
authors: Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors: Alexander T
authors: AT
authors: Faje
authors: Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors: Ela J
authors: EJ
authors: Cross
authors: Biostatistics Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors: Hang
authors: H
authors: Lee
authors: Maine Medical Center Research Institute, Scarborough, ME, USA.
authors: Clifford J
authors: CJ
authors: Rosen
authors: Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
authors: Mary L
authors: ML
authors: Bouxsein
authors: Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
authors: Anne
authors: A
authors: Klibanski
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000856:Anorexia Nervosa / Q000097:blood / Q000503:physiopathology*; D016723:Bone Remodeling; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000648:ultrastructure; D016022:Case-Control Studies; D005260:Female; D005346:Fibroblast Growth Factors / Q000097:blood*; D020342:Finite Element Analysis; D006801:Humans
chemical_list: C414620:fibroblast growth factor 21; D005346:Fibroblast Growth Factors
keywords: Anorexia nervosa; Bone microarchitecture; Bone strength; FGF-21