Hip bone strength indices in overweight and control adolescent boys

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.