title: The influence of dairy consumption, sedentary behaviour and physical activity on bone mass in Flemish children: a cross-sectional study.
abstract: BACKGROUND
  This cross-sectional study aimed to look for an association in young children between whole body bone mineral content (BMC) and areal bone mineral density (aBMD) and dairy consumption as well as sedentary behaviour (SB) and physical activity (PA). Moreover, we investigated whether there was an interaction effect between dairy consumption and SB or PA on BMC and aBMD.
  
  
  METHODS
  Healthy children (6-12 years) were recruited from primary schools. Body composition and whole body bone mass were measured with dual-energy X-ray absorptiometry (DXA), dairy consumption was assessed with a food frequency questionnaire (FFQ) and PA and SB with an accelerometer. In total, 272 children underwent a DXA scan. Complete FFQ data were available for 264 children and 210 children had matching data from accelerometry recordings. Regression analyses were used to study the associations between (1) BMC and aBMD and (2) dairy consumption, SB and PA, adjusting for age, gender, pubertal stage, height and body composition.
  
  
  RESULTS
  Dairy consumption was positively associated with whole body BMC and aBMD (absolute value as well as z-score), after correction for relevant confounders. SB was negatively associated with aBMD z-score and light PA was positively associated with both BMC and aBMD z-score. No gender differences were found. Moreover, an interaction effect between vigorous PA (VPA) and dairy consumption on aBMD (z-score) and BMC z-score was found, indicating that children with both high VPA and high dairy consumption had higher values for BMC and aBMD of the whole body minus the head.
  
  
  CONCLUSIONS
  Already at young age, PA and dairy consumption positively influence whole body bone mass assessed by DXA. Moreover, this study indicates clearly that SB is negatively associated with whole body bone density. Promoting regular PA and sufficient dairy consumption in young children and limiting SB can be expected to positively influence their bone mass accumulation, which can help in the prevention of osteoporosis later in life.
authors.affiliation: Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, 4K3, De Pintelaan 185, B-9000, Ghent, Belgium. Isabelle.Sioen@UGent.be.|FWO, Research Foundation Flanders, Egmontstraat 5, 1000, Brussels, Belgium. Isabelle.Sioen@UGent.be.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Sioen
authors.affiliation: Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, 4K3, De Pintelaan 185, B-9000, Ghent, Belgium.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Michels
authors.affiliation: Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, 4K3, De Pintelaan 185, B-9000, Ghent, Belgium.
authors.forename: Carolien
authors.initials: C
authors.lastname: Polfliet
authors.affiliation: Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, 4K3, De Pintelaan 185, B-9000, Ghent, Belgium.
authors.forename: Stephanie
authors.initials: S
authors.lastname: De Smet
authors.affiliation: FWO, Research Foundation Flanders, Egmontstraat 5, 1000, Brussels, Belgium.|Department of Movement and Sport Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: D'Haese
authors.affiliation: Department of Pediatrics, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Inge
authors.initials: I
authors.lastname: Roggen
authors.affiliation: Department of Pediatrics, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Brussels, Belgium.|Department of Pediatrics, Ghent University Hospital, Ghent, Belgium.
authors.forename: Jean
authors.initials: J
authors.lastname: Deschepper
authors.affiliation: Department of Endocrinology, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.|Unit for Osteoporosis and Metabolic Bone Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Stefan
authors.initials: S
authors.lastname: Goemaere
authors.affiliation: ImFine Research Group, Department of Health and Human Performance, Faculty of Physical Activity and Sport Sciences, Universidad Politécnica de Madrid, Madrid, Spain.
authors.forename: Jara
authors.initials: J
authors.lastname: Valtueña
authors.affiliation: Department of Public Health, Faculty of Medicine and Health Sciences, Ghent University, 4K3, De Pintelaan 185, B-9000, Ghent, Belgium.|Department of Health Sciences, Vesalius, University College Ghent, Ghent, Belgium.
authors.forename: Stefaan
authors.initials: S
authors.lastname: De Henauw
mesh_terms: D015502:Absorptiometry, Photon; D001530:Belgium; D001823:Body Composition; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000502:physiology*; D002648:Child; D003430:Cross-Sectional Studies; D003611:Dairy Products / Q000706:statistics & numerical data*; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology; D057185:Sedentary Behavior