| PART ONE:Bone mineral density and geometric measurements with DXA at proximal femur in normal subjects.Objective:To evaluate bone mineral density and geometric structure of the proximal femur in normal subjects for analyzing the relationship between geometric structure with age,height and weight.Material and methods:DXA measurements of the proximal femur were obtained from 3030 normal subjects of which there were 549 males with age from 20-90 years (mean age 48.38±16.28 yeas), as well as 2481 females with age from 20-93 years (mean age 56.33±12.93 years). DXA measurements included bone mineral density (BMD) and structural variables with Hip Strength Analysis (HSA) software, which including cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), hip axis length (HAL), femoral neck width (FNW), neck shaft angle (NSA) and femur strength index (FSI).Results:The older with subjects, the lower of BMD (femoral neck and total femur) for both males and females; Increased weight covered the age-time from 40-70 yeas in both genders. No differences of HAL and FNW were found in the study. There was a gender differences for FSI and NSA:FSI and NSA decreased with age increasing in females, but not in males.Conclusions:The age-time period of height reduction and weight increasing should extreme caution for prevention and treatment with related disease. Similar to bone mineral density, decrease of CSMI,CSA and FSI is with age increasing; CSMI,CSA and FSI could be used for to predict fracture risk, Neck shaft angle could be considered as one of the factors to explain high fracture risk in females. PART TWO:Bone mineral density and geometric measurements with DXA at proximal femur in subjects with and without hip fracturesObjective:To evaluate the differences of bone mineral density and geometric structures of the proximal femur in subjects with and without hip fracture.Material and methods:DXA measurements of the proximal femur were obtained from 90 subjects with hip fractures and 100 without hip fractures. With fractures there were 73 females with age from 44-84 years (mean age 68.7±9.2 yeas), as well as 17 males with age from 41-85 years (mean age 65.6±13.5 years),without fractures there were 80 females with age from 53-82 years (mean age 66.08±6.6 years), as well as 20 males with age from 48-87years (mean age 63.35±10.8 years).DXA measurements included bone mineral density (BMD) and structural variables with Hip Strength Analysis (HSA) software, which including cross-sectional moment of inertia (CSMI), cross-sectional area (CSA), hip axis length (HAL), femoral neck width (FNW), neck shaft angle (NSA) and femur strength index (FSI).Results:There were a difference of BMD both female and male subjects with and without fracture.(all p values<0.01); The difference in proximal femur structural variables with and without fracture were consistent with the ROC results:there were significantly differences of CSA, FNW,NSA in patients with and without hip fractures (all pvalues<0.01); Except male NSA without differences, there were significantly differences of CSMI,FNW and NSA for female and male subjects with and without fracture.(all p values<0.01), which showed significantly larger area under ROC curves (all p values<0.01). Other femur structural variables were not shown to have significantly difference for female and male subjects with and without fracture.(all p values>0.05), and no significantly ROC results were found.(all p values>0.05).Conclusions:Among the proximal femur structural variables (CSMI, CSA, HAL, FNW, NSA and FSI) measured with DXA, factors of CSA,FNW and NSA may play more important role to evaluate hip fracture risk. It is assumed that changes cortical thickness decreases or porosity should be considered as more significant value for hip fracture mechanism,even femoral neck width increased with hip fractures.
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