Bone Geometric Properties of the Femoral Neck in Underweight Eumenorrheic Women

Abstract The aim of this study was to describe femoral neck (FN) geometry among eumenorrheic underweight women around the age of peak bone mass. Proximal femur geometry and body composition were assessed in 12 underweight women and in 24 healthy controls using dual-energy X-ray absorptiometry. The Hip Structural Analysis program was used to determine bone geometry at the FN. The cross-sectional area (CSA) and the cross-sectional moment of inertia (CSMI) were significantly lower in underweight women than in controls ( p Z ) and strength index in underweight women ( p Z , and neck-shaft angle ( r  = 0.428–0.611, p Z , and neck-shaft angle were no more statistically significant between the 2 groups. The multivariate analysis retained LM as the main predictor of CSA, CSMI, and Z in the whole population. The present study suggests that thinness is associated with low resistance to axial forces (CSA) and bending load ( Z and CSMI) in adult eumenorrheic women. LM seems to be a key determinant of FN geometry in underweight women.