title: Bone mass and bone metabolism markers during adolescence: The HELENA Study.
abstract: OBJECTIVE
  The assessment of bone mineral content (BMC) and density (BMD) status in children and adolescents is important for health and the prevention of diseases. Bone metabolic activity could provide early information on bone mass development. Our aim was to describe bone mass and metabolism markers according to age and Tanner stage in adolescents.
  
  
  METHODS
  Spanish adolescents (n = 345; 168 males and 177 females) aged 12.5-17.5 years participated in this cross-sectional study. Body composition variables were measured by dual-energy X-ray absorptiometry. Serum osteocalcin (n = 101), aminoterminal propeptide of type I procollagen (n = 92) and β-isomerized C-telopeptides (β-CTX, n = 65) and urine samples (β-CTX; n = 237) were analyzed by electrochemiluminescence immunoassay.
  
  
  RESULTS
  Analysis of covariance showed that females had higher values for BMC and BMD in most of the regions. Both males and females had a significant decrease in bone markers while sexual maturation increases (all p < 0.05). Males had an increased bone turnover compared to females (all p < 0.05, except for urine β-CTX in Tanner ≤IV).
  
  
  CONCLUSIONS
  Our results support the evidence of dimorphic site-specific bone accretion between sexes and show an increased bone turnover in males, suggesting higher metabolic activity.
authors.affiliation: GENUD (Growth, Exercise, NUtrition and Development) Research Group, University of Zaragoza, Zaragoza, Spain. lgracia@unizar.es
authors.forename: L
authors.initials: L
authors.lastname: Gracia-Marco
authors.forename: G
authors.initials: G
authors.lastname: Vicente-Rodríguez
authors.forename: J
authors.initials: J
authors.lastname: Valtueña
authors.forename: J P
authors.initials: JP
authors.lastname: Rey-López
authors.forename: A E
authors.initials: AE
authors.lastname: Díaz Martínez
authors.forename: M I
authors.initials: MI
authors.lastname: Mesana
authors.forename: K
authors.initials: K
authors.lastname: Widhalm
authors.forename: J R
authors.initials: JR
authors.lastname: Ruiz
authors.forename: M
authors.initials: M
authors.lastname: González-Gross
authors.forename: M J
authors.initials: MJ
authors.lastname: Castillo
authors.forename: L A
authors.initials: LA
authors.lastname: Moreno
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000375:Aging / Q000378:metabolism; D000886:Anthropometry; D015415:Biomarkers; D001823:Body Composition / Q000502:physiology; D001846:Bone Development / Q000502:physiology*; D001862:Bone Resorption / Q000378:metabolism; D001842:Bone and Bones / Q000378:metabolism*; D002136:Calcium, Dietary / Q000008:administration & dosage; D024042:Collagen Type I / Q000097:blood; D005260:Female; D006801:Humans; D008297:Male; D009929:Organ Size / Q000502:physiology; D015675:Osteocalcin / Q000097:blood; D011627:Puberty / Q000502:physiology; D012727:Sex Characteristics
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D024042:Collagen Type I; D015675:Osteocalcin