Physical activity is associated with bone geometry of premenarcheal girls in a dose-dependent manner.
OBJECTIVE
To determine the relationship between habitual physical activity (PA) level and peripheral qualitative computed tomography-determined quantitative tibia characteristics of premenarcheal girls.


METHODS
Premenarcheal girls matched for age (10-13 years), bone age and maturity level were assigned into: a) low PA group (LPA, n=25), b) moderate PA group (MPA, n=17), and c) high PA group (HPA, n=18). Participants' daily dietary intake, tibia's geometry and serum levels of calcium and vitamin D were assessed.


RESULTS
Premenarcheal girls demonstrating HPA exhibited greater pericortical thickness, cross-sectional area (CSA) and bone mineral content (BMC) (p<.001) in cortical bone, greater BMC, volumetric bone density (vBMD) and polar stress strength index (SSIp) in trabecular bone (p<0.001-0.05) and greater total BMC (p<.05) and vBMD (p<.01) when compared to their physically inactive or moderately active counterparts. MPA exhibited greater values of cortical BMC (p<.01) and SSIp (p<.05) than LPA. Partial correlation analysis (adjusted for BMI) revealed modest associations between PA score and bone geometry parameters (r=0.36-0.49, p<.05) at 38% of tibia length.


CONCLUSIONS
Habitual PA affects geometry of both cortical and trabecular areas of a long bone of premenarcheal girls in a dose-dependent manner. Specifically, PA increases both the density and size of cortical bone but only the density of trabecular bone during preadolescence. Given the importance of peak bone mass for future fracture risk, high levels of PA during childhood could be a major target for public health interventions aimed at optimising bone health in prepubertal children when the greatest bone gains occur.
Department of Physical Education and Sport Sciences, Democritus University of Thrace, University Campus, 69100 Komotini, Greece.
Maria
M
Michalopoulou
Antonis
A
Kambas
Diamanda
D
Leontsini
Athanasios
A
Chatzinikolaou
Dimitrios
D
Draganidis
Alexandra
A
Avloniti
Dimitrios
D
Tsoukas
Eleni
E
Michopoulou
Georgios P
GP
Lyritis
Nikolaos
N
Papaioannou
Symeon
S
Tournis
Ioannis G
IG
Fatouros
D015502:Absorptiometry, Photon; D019412:Anatomy, Cross-Sectional; D000886:Anthropometry; D015992:Body Mass Index; D001835:Body Weight / Q000502:physiology; D015519:Bone Density / Q000502:physiology; D001842:Bone and Bones / Q000033:anatomy & histology*; D002118:Calcium / Q000097:blood; D002648:Child; D004032:Diet; D005260:Female; D006801:Humans; D009043:Motor Activity / Q000502:physiology*; D013977:Tibia / Q000000981:diagnostic imaging; D014807:Vitamin D / Q000097:blood
D014807:Vitamin D; D002118:Calcium
25(OH)D; ANOVA; Analysis of variance; BMC; BMD; BMI; Body mass index; Bone development; Bone mineral content; Bone mineral density; CSA; Cross-sectional area; DXA; Dual energy X-ray absorptiometry; Exercise; HPA; High PA; Hydroxyvitamin D; LPA; Low PA; MCSA; MET; MPA; Metabolic Equivalent of Task; Moderate PA; Muscle cross-sectional area; PA; Peripheral quantitative computed tomography; Peripheral quantitative computerized tomography; Physical activity; Pre-adolescence; SSIp; Stress strength index in torsion; Volumetric bone mineral density; pQCT; vBMD