title: Loss of bone strength in response to exercise-induced weight loss in obese postmenopausal women: results from a pilot study.
abstract: OBJECTIVE
  Exercise-induced weight loss (WL) can lead to decreased areal bone mineral density (aBMD). It is unknown whether this translates into decreased volumetric BMD (vBMD) or bone strength. The purpose of this pilot study was to determine whether exercise-induced WL results in decreased vBMD and bone strength in postmenopausal women.
  
  
  METHODS
  Fourteen subjects participated in a 4-month endurance exercise WL intervention. A weight stable (WS) control group (n=10) was followed for 4 months. Proximal femur aBMD was measured by DXA. Femoral neck vBMD and estimates of bone strength (cross-sectional moment of inertia (CSMI) and section modulus (SM)) were measured by quantitative CT.
  
  
  RESULTS
  Women were 54.6±2.4 years, BMI 32.1±5.9 kg/m(2) and 54.4±2.9 years, BMI 27.9±3.6 kg/m(2) in the WL and WS groups, respectively. The WL group lost 3.0±2.6 kg which was predominately fat mass. There was a significant decrease in SMmax. Changes in CSMImax and total hip aBMD were not significant. Total hip vBMD did not decrease significantly in response to WL. There were no significant changes in the WS group.
  
  
  CONCLUSIONS
  WL may lead to decreased bone strength before changes in BMD are detected. Further studies are needed to determine whether bone-targeted exercise can preserve bone strength during WL.
authors.affiliation: Division of Geriatric Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Shea
authors.forename: W S
authors.initials: WS
authors.lastname: Gozansky
authors.forename: V D
authors.initials: VD
authors.lastname: Sherk
authors.forename: T A
authors.initials: TA
authors.lastname: Swibas
authors.forename: P
authors.initials: P
authors.lastname: Wolfe
authors.forename: A
authors.initials: A
authors.lastname: Scherzinger
authors.forename: E
authors.initials: E
authors.lastname: Stamm
authors.forename: W M
authors.initials: WM
authors.lastname: Kohrt
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology; D005081:Exercise Therapy / Q000009:adverse effects*; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D006801:Humans; D008875:Middle Aged; D009765:Obesity; D010865:Pilot Projects; D017698:Postmenopause / Q000502:physiology*; D014057:Tomography, X-Ray Computed; D015431:Weight Loss / Q000502:physiology*; D061217:Weight Reduction Programs / Q000379:methods