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HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

The purpose of this study was to analyse the relationships between age, morphological characteristics (weight, height, body mass index (BMI), fat and lean mass), daily calcium intake (DCI), physical activity and bone mineral apparent density (BMAD) of the whole body (WB), lumbar spine (L2-L4), femoral neck (FN) and 1/3 radius in a group of Lebanese adolescent boys. This study included 60 Lebanese adolescent (16.8 ± 2.1 years old) boys. Body composition and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA). BMAD values of the WB, L2-L4, FN and 1/3 radius were calculated. Physical activity and DCI were assessed using questionnaires. Age was positively related to WB, L2-L4 and 1/3 radius BMD and BMAD. Weight, lean mass and BMI were positively related to WB, L2-L4, FN and 1/3 radius BMD. Moreover, weight, lean mass and BMI were positively associated with L2-L4 and FN BMAD but not with BMAD of the WB and the 1/3 radius, while fat mass percentage was negatively associated with WB BMAD. In conclusion, this study shows that weight, lean mass and BMI are positively associated with BMAD of the weight-bearing bones (L2-L4 and FN) but not with BMAD of the WB and the 1/3 radius in adolescent boys.

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The influence of being overweight on bone strength in adolescents remains controversial. The aim of this study was to compare hip bone strength indices in overweight and control adolescent boys using hip structure analysis (HSA). This study included 25 overweight adolescent boys [body mass index (BMI) >25 kg/m(2)] and 31 maturation-matched controls (BMI <25 kg/m(2)). Body composition and bone mineral density were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone strength, DXA scans were analyzed at femoral neck, intertrochanteric, and femoral shaft by the HSA program. Cross-sectional area (CSA), an index of axial compression strength, section modulus (Z), an index of bending strength, cross-sectional moment of inertia (CSMI), cortical thickness (CT), and buckling ratio (BR) were measured from bone mass profiles. Body weight, lean mass, fat mass, and BMI were higher in overweight boys compared to controls (P < 0.001). CSA, CSMI, and Z of the three sites (femoral neck, intertrochanteric, and femoral shaft) were higher in overweight boys compared to controls (P < 0.01). BR was not significantly different between the two groups at the three sites. After adjustment for either body weight, BMI, or fat mass, using a one-way analysis of covariance, there were no differences between the two groups regarding the HSA variables (CSA, Z, CSMI, CT, and BR). After adjusting for lean mass, overweight boys displayed higher values of femoral shaft CSA, CSMI, and Z in comparison to controls (P < 0.05). In conclusion, this study suggests that overweight adolescent boys have greater indices of bone axial and bending strength in comparison to controls at the femoral neck, the intertrochanteric, and the femoral shaft.