The relationship between men hip geometric structure and body composition in Shanghai area

Abstract

Objective To investigate the correlation between hip geometric structure and body composition including bone mineral density （BMD） , lean mass, and fat mass. Methods A total of 1 168 healthy mail residents in Shanghai were divided into three age groups ： young （ 21-40 years ） , middle-aged （ 41-60 years） , and older （ 〉 60 years） , and were evaluated by assessing BMD of lumber spine and hip, total lean mass, total fat mass, and hip geometric parameters such as cross-sectional area, average cortical thickness, and bucking ratio at narrow neck, intertrochanteric, and shaft. Correlation analysis was performed by Pearson （normal distribution ） or Pearson （ abnormal distribution） test, and attribution analysis was performed by stepwise test of multiple regressions. Results （ 1 ） The peak BMD values of the spine and total hip were observed in the 21-30 years old group. The peak lean mass and fat mass were observed in the 31-40 years old group. The hip geometric parameters including cross-sectional area and average cortical thickness at narrow neck, intertrochanteric and shaft, reached peaks by 21-30 years, and valley bucking ratio at three regions mentioned above was observed by 21-30 years as well. （2） The correlation between hip BMD and hip geometric structure was most marked at all three regions. Lean mass showed significantly positivecorrelalion with cross-sectional are and negalive correlation with bueking ratio.The effect of fat mass on hip geometric purneters al the three regions was inconsistent （ 3 ） Fat mass and percentage of body fat （ Fat % ） showed negalive correlation wilh cross-sectional area and average corlical Ihiekness 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 yiehled the largest positive eontrihution to cross- sectioual area and avere cortical thickness at all three regions in young group, However, Ihe conlribution produced by trunk lean mass became lhe largest positive conlribution to cross-seelional area and average em＇tic~ll thickness in older group. Conclusions Ainmg all the body composition parameters, hip BMD has showed the most marked correlaltion with hip geometric structure. Lean mass is ranked the second in the correlalion. The impacts of fat mass and lean mass on hip geometry are changing with aging and their different tissue distributions. Key words: Hip geometric structure; Body compsition; Bone mineral density; Lean mass ; Fat mass