DXA Bone Mineral Density And Hip Strength Analysis In Overweight And Normal Weight Adolescents

ObjectiveThe aim of this study was to determine the influence of being overweight on bone mineraldensity(BMD)，and to compare hip bone strength indices in overweight adolescents andgender-matched normal weight controls using hip structural analysis (HSA).MethodsThis study included72overweight adolescents (29girls,43boys) and67gender-matchednormal weight controls (40girls,27boys). Whole body bone mineral area(WBBMA), wholebody bone mineral content (WBBMC)，whole body (WB)BMD, femoral neck (FN) BMD, totalhip(TH)BMD, lumbar spine (L1-L4)BMD and body composition (lean mass and fat mass) wereassessed by dual-energy X-ray absorptiometry (DXA). DXA HSA was performed using LunarenCORE, version10.5software. Structural parameters derived by HSA were the bonecross-sectional area (CSA)，the cross-sectional moment of inertia (CSMI) and the sectionmodulus (Z).Result①DXA measurements of weight, body mass index (BMI), LM, FM, FM%, WBBMC andBMD (WB, L1-L4, TH and FN) were higher in overweight adolescents compared togender-matched control（sP＜0.001）. After adjusting for weight, BMI, lean mass, fat mass, thesedifferences disappeared. Lean mass and fat mass were positively correlated to WBBMC andWBBMD for adolescent girls（r=0.533~0.784, P＜0.001）. Lean mass was positively correlatedto WBBMC and WBBMD（r=0.438~0.699, P＜0.05）, but fat mass was not related to WBBMCand WBBMD for adolescent boys.②CSA, CSMI, and Z of femoral neck were higher inoverweight adolescents compared to controls (P＜0.05). After adjustment for either body weightor lean mass, using a one-way analysis of covariance, there were no differences between the twogroups regarding the HSA variables (CSA, CSMI and Z). After adjusting for fat mass,overweight boys displayed higher values of CSA, CSMI and Z in comparison to controls (P＜ 0.05), but there were not signicant differences between overweight girls and controls. Lean massand fat mass were all positively correlated with all HSA parameters (CSMI, CSA and Z) foradolescent girls（r=0.562~0.735, P＜0.05）. Lean mass was positively correlated with all HSAparameters (CSMI, CSA and Z)（r=0.673~0.729, P＜0.05）, but fat mass was not positivelyrelated with all HSA parameters (CSMI, CSA and Z) for adolescent boys.ConclusionOverweight adolescents do have higher BMD when compared with controls. Overweightadolescents have greater indices of proximal femur bone geometry in comparison to controls atthe femoral neck. Proximal femur bone geometric strength in overweight adolescents wasappropriately adapted to lean mass.