ABSTRACT
correlation with cross-sectional area and negative correlation with bucking ratio. The effect of fat mass on hip geometric parameters at the three regions was inconsistent. (3) Fat mass and percentage of body fat ( Fat%) showed negative correlation with cross-sectional area and average cortical thickness and positive correlation with bucking ratio in young group. However, the negative contribution produced by fat mass and Fat% to hip geometric structure became weaker gradually in middle-aged and older groups. ( 4 ) Limb lean mass yielded the largest positive contribution to cross-sectional area and average cortical thickness at all three regions in young group. However, the contribution produced by trunk lean mass became the largest positive contribution to cross-sectional area and average cortical thickness in older group. Conclusions Among all the body composition parameters, hip BMD has showed the most marked correlation with hip geometric structure. Lean mass is ranked the second in the correlation. The impacts of fat mass and lean mass on hip geometry are changing with aging and their different tissue distributions.