title: Lean soft tissue contributes more to bone health than fat mass independent of physical activity in women across the lifespan.
abstract: OBJECTIVE
  To investigate the association between lean soft tissue (LST) and fat mass (FM) on bone health variables in women across the lifespan, while taking into account the influence of objectively measured habitual physical activity (PA).
  
  
  METHODS
  A total of 104 women, 37 young (23.3 ± 2.6 years), 28 middle-age (49.2 ± 5.4 years), and 39 old (68.3 ± 6.4 years) participated in this cross-sectional study. All underwent a DXA scan and wore a pedometer for 7 days.
  
  
  METHODS
  Bone mineral content (BMC) and BMD of the whole body (WB), lumbar spine (LS) and proximal femur (PF), and body composition (FM and LST) were assessed with DXA and PA (steps/day) was assessed from 7 day pedometer counts.
  
  
  RESULTS
  LST was significantly and positively associated with PF and LS BMD (r = 0.34; 0.67, p < 0.05), and WB, PF and LS BMC (r range = 0.41-0.59, p < 0.05) in all age groups and WB BMD in the middle-age group (r = 0.72, p < 0.05) independent of PA, FM, and hormonal status. FM was not positively associated with any bone variable in any age group when adjusted for PA, LST, and hormonal status. PA was significantly associated with WB BMD in the middle-age group (r = 0.60, p < 0.05), independent of LST, FM, and hormonal status.
  
  
  CONCLUSIONS
  LST contributes more to bone health in women across the lifespan than FM, independent of PA and hormonal status.
authors: Center for Sport and Health Sciences, University of Iceland, Lindarbraut 4, 840 Laugarvatn, Iceland. Electronic address: ghinriks@hi.is.
authors: Gunnhildur
authors: G
authors: Hinriksdóttir
authors: Center for Sport and Health Sciences, University of Iceland, Lindarbraut 4, 840 Laugarvatn, Iceland.
authors: Sigurbjörn Á
authors: SÁ
authors: Arngrímsson
authors: Department of Kinesiology and Physical Education, Northern Illinois University, DeKalb, IL 60115 USA.
authors: Mark M
authors: MM
authors: Misic
authors: Department of Kinesiology, 101A Ramsey Center, 300 River Road, University of Georgia, Athens, GA 30602 USA.
authors: Ellen M
authors: EM
authors: Evans
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000502:physiology*; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition / Q000502:physiology*; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D055815:Young Adult
keywords: Bone density; Fat mass; Lean soft tissue; Pedometer; Women