title: Soft tissues, areal bone mineral density and hip geometry estimates in active young boys: the PRO-BONE study.
abstract: OBJECTIVE
  Soft tissues, such as fat mass (FM) and lean mass (LM), play an important role in bone development but this is poorly understood in highly active youths. The objective of this study was to determine whether FM or LM is a stronger predictor of areal bone mineral density (aBMD) and hip geometry estimates in a group of physically active boys after adjusting for height, chronological age, moderate-to-vigorous physical activity (MVPA), FM, and LM.
  
  
  METHODS
  Participants included 121 boys (13.1 ± 1.0 years) from the PRO-BONE study. Bone mineral content (BMC) and aBMD were measured at total body, femoral neck and lumbar spine using dual-energy X-ray absorptiometry (DXA), and hip structural analysis was used to estimate bone geometry at the femoral neck. Body composition was assessed using DXA. The relationships of FM and LM with bone outcomes were analysed using simple and multiple linear regression analyses.
  
  
  RESULTS
  Pearson correlation coefficients showed that total body (less head) aBMD was significantly correlated with LM but not FM. Multiple linear regression analyses showed that FM, after accounting for height, age, MVPA and LM had no significant relationship with aBMD or hip geometry estimates, except for arms aBMD. By contrast, there were positive associations between LM and most aBMD and hip geometry estimates, after accounting height, age, MVPA and FM.
  
  
  CONCLUSIONS
  The results of this study suggest that LM, and not FM, is the stronger predictor of aBMD and hip geometry estimates in physically active boys.
  
  
  BACKGROUND
  ClinicalTrials.gov ISRCTN17982776.
authors.affiliation: Children's Health and Exercise Research Centre, Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK.|Peninsula Medical School, Exeter, UK.
authors.forename: Kelly
authors.initials: K
authors.lastname: Wilkinson
authors.affiliation: Children's Health and Exercise Research Centre, Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK.
authors.forename: Dimitris
authors.initials: D
authors.lastname: Vlachopoulos
authors.affiliation: Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada.
authors.forename: Panagiota
authors.initials: P
authors.lastname: Klentrou
authors.affiliation: IGOID Research Group, University of Castilla-La Mancha, Toledo, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Ubago-Guisado
authors.affiliation: YCARE (Youth/Child cArdiovascular Risk and Environmental) Research Group, University of São Paulo, School of Medicine, São Paulo, São Paulo, Brazil.|Growth, Exercise, Nutrition and Development Research Group, University of Zaragoza, Zaragoza, Spain.|Johns Hopkins Bloomberg School of Public Health, Department of Epidemiology, Baltimore, MD, UK.
authors.forename: Augusto César Ferreira
authors.initials: AC
authors.lastname: De Moraes
authors.affiliation: Children's Health and Exercise Research Centre, Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Barker
authors.affiliation: Children's Health and Exercise Research Centre, Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Williams
authors.affiliation: Growth, Exercise, Nutrition and Development Research Group, University of Zaragoza, Zaragoza, Spain.
authors.forename: Luis A
authors.initials: LA
authors.lastname: Moreno
authors.affiliation: Children's Health and Exercise Research Centre, Sport and Health Sciences, St. Luke's Campus, University of Exeter, Exeter, EX1 2LU, UK. L.A.Gracia-Marco@exeter.ac.uk.|Growth, Exercise, Nutrition and Development Research Group, University of Zaragoza, Zaragoza, Spain. L.A.Gracia-Marco@exeter.ac.uk.
authors.forename: Luis
authors.initials: L
authors.lastname: Gracia-Marco
mesh_terms: D000273:Adipose Tissue / Q000000981:diagnostic imaging* / Q000254:growth & development; D000293:Adolescent; D015519:Bone Density; D002648:Child; D015444:Exercise; D005269:Femur / Q000000981:diagnostic imaging* / Q000254:growth & development; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000254:growth & development
keywords: Adolescents; Body composition; Bone health; Fat mass; Hip structural analysis; Lean mass