title: Bone mineral density of total body, spine, and femoral neck in children and young adults: a cross-sectional and longitudinal study.
abstract: Bone mineral density (BMD) of total body (TBMD), lumbar spine (L2-4), and femoral neck was measured in 266 normal subjects (136 males) aged 4-27 years (mean 13 years) using dual-energy x-ray absorptiometry (DXA). BMD of all sites increased significantly with age until 17.5 years in males and 15.8 years in females, except for femoral neck BMD in females, which peaked at age 14.1 years. Males had higher peak TBMD, which was attributed to greater weight and lean tissue mass. In contrast, despite a later timing, peak L2-4 BMD in males was not different from that in females. Before peak BMD, weight was the best predictor of TBMD and L2-4 BMD in both sexes (r2 ranged from 0.77 to 0.88), whereas femoral neck BMD was predicted equally by height and weight. Longitudinal information collected from 53 (25 boys) of these children, aged 4-16.9 years, showed that the average annualized gain in TBMD was 0.047 g/cm2 for boys and 0.039 g/cm2 for girls. No significant difference in the association between age and BMD (slopes) was found between cross-sectional and longitudinal data for either sex. We conclude that the timing for peak BMD was consistent for total body, lumbar spine, and femoral neck for each sex. The earlier peak BMD in females is most likely related to earlier puberty. The cross-sectional normative data of this study are useful in serving as a standard for serial assessment in health and disease states.
authors: Robert Vines Growth Research Centre, Royal Alexandra Hospital for Children, Sydney, New South Wales, Australia.
authors: P W
authors: PW
authors: Lu
authors: J N
authors: JN
authors: Briody
authors: G D
authors: GD
authors: Ogle
authors: K
authors: K
authors: Morley
authors: I R
authors: IR
authors: Humphries
authors: J
authors: J
authors: Allen
authors: R
authors: R
authors: Howman-Giles
authors: D
authors: D
authors: Sillence
authors: C T
authors: CT
authors: Cowell
mesh_terms: D015502:Absorptiometry, Photon; D000293:Adolescent; D000328:Adult; D000375:Aging / Q000502:physiology; D001827:Body Height / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005272:Femur Neck / Q000502:physiology*; D006801:Humans; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000502:physiology*; D008297:Male; D011627:Puberty / Q000502:physiology; D012016:Reference Values; D012044:Regression Analysis; D012727:Sex Characteristics