Geometric indices of hip bone strength in overweight and control elderly men.

Abstract

The aim of this study was to compare geometric indices of hip bone strength in overweight and control elderly men. This study included 16 overweight (Body mass index (BMI) > 25 kg/m2) elderly men (aged 65-84 years) and 38 age-matched controls (BMI < 25 kg/m2). Body composition and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DXA). To evaluate hip bone geometry, DXA scans were analyzed at the femoral neck, the intertrochanteric region, and the femoral shaft by the Hip Structure Analysis (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), an index of structural rigidity, cortical thickness (CT) and buckling ratio (BR) were measured from bone mass profiles. Lean mass, body weight, fat mass and BMI were higher in overweight men compared to controls (p < 0.001). CSA and Z were higher in overweight subjects compared to controls (p < 0.05) at the three regions (femoral neck, intertrochanteric and femoral shaft). After adjustment for age, CSA and Z of the intertrochanteric region and the femoral shaft remained significantly higher in overweight men compared to controls (p < 0.05). After adjustment for either body weight, BMI or lean mass, there were no differences between the two groups (overweight and controls) regarding the HSA variables (CSA, CSMI, Z, CT and BR) of the three regions. This study suggests that overweight elderly men have greater indices of bone axial and bending strength in comparison to controls at the intertrochanteric and the femoral shaft.