title: Long bone robustness during growth: A cross-sectional pQCT examination of children and young adults aged 5-29years.
abstract: Skeletal robustness (cross-section size relative to length) is associated with stress fractures in adults, and appears to explain the high incidence of distal radius fractures in adolescents. However, little is known about the ontogeny of long bone robustness during the first three decades of life. Therefore, we explored the ontogeny of tibial, fibular, ulnar and radial robustness in a cross-sectional sample of 5 to 29year-old volunteers of both sexes. Peripheral quantitative computed tomography (pQCT) was used to evaluate cross-sections of the leg (4%, 14%, 38% and 66%), and forearm (4%, and 66%) in N=432 individuals. Robustness was evaluated as the total bone area divided by bone length. Differences between age-groups, sexes, and age-group×sex interactions were evaluated with ANOVA with Tukey's post hocs where appropriate. Most bone sites exhibited more robust bones in men than women (P<0.001 to 0.02), and in older age-groups than younger (P<0.001). Sex×age-group interaction was observed at the 66% and 38% tibia sites with robustness increasing more with age in men than in women (P=0.006 to 0.042). Post-hoc analyses indicated no sex differences prior to 13years-of-age, and notable exceptions to increasing robustness with age at the 4% radial and 66% tibial sites, which exhibited reduced robustness in age groups close to peak height velocity. In conclusion, the present results suggest that very little sexual dimorphism in long bone robustness exists prior to puberty, and that divergence occurs primarily after cessation of longitudinal growth. A period of relative diaphyseal slenderness was identified at age-groups coinciding with the adolescent growth spurt, which may be related to the relatively high incidence of frank and stress fracture in adolescents.
authors.affiliation: Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia. Electronic address: t.rantalainen@deakin.edu.au.
authors.forename: Timo
authors.initials: T
authors.lastname: Rantalainen
authors.affiliation: Menzies Health Institute Queensland, School of Allied Health Sciences, Griffith University, Gold Coast, Australia.
authors.forename: Benjamin K
authors.initials: BK
authors.lastname: Weeks
authors.affiliation: Menzies Health Institute Queensland, School of Allied Health Sciences, Griffith University, Gold Coast, Australia.
authors.forename: Rossana C
authors.initials: RC
authors.lastname: Nogueira
authors.affiliation: Menzies Health Institute Queensland, School of Allied Health Sciences, Griffith University, Gold Coast, Australia.
authors.forename: Belinda R
authors.initials: BR
authors.lastname: Beck
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001846:Bone Development; D001842:Bone and Bones / Q000033:anatomy & histology / Q000000981:diagnostic imaging* / Q000502:physiology*; D002648:Child; D005260:Female; D005360:Fibula / Q000033:anatomy & histology / Q000254:growth & development; D006801:Humans; D008297:Male; D013977:Tibia / Q000033:anatomy & histology / Q000254:growth & development; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult
keywords: BPAQ; Bone QCT; Growth; Morphology; Ontogeny; Puberty