Correlational Research Among Bone Mineral Density,Body Composition And Bone Metabolic Markers In Elderly Obese Population

Objective:To investigate relationship between bone mineral density and body composition and bone metabolic markers in elderly obese people.Methods:From January 2017 to March 2018,71 elderly people in the geriatrics department of Qilu Hospital of Shandong University were selected.The age was 60～87 years old with an average age of 72.06±7.27 years.According to the ASBP criteria,the subjects were divided into two groups:36 cases were obese group with body fat rate(male ≥ 25%,female ≥ 30%),and 35 cases were non-obese group with body fat rate(male<25%,female<35%).All subjects were asked in detail about the history of the disease and examined.Gender,age,height,weight,waist circumference,hip circumference were recorded and calculated.The body mass index(BMI)was calculated,and the indexes of serum calcium,triglyceride,low density lipoprotein cholesterol(LDL-C),alkaline phosphatase(ALP),uric acid(UA)and bone metabolic markers were determined.Bone mineral density(BMD)and body composition were determined by dual energy X-ray absorptiometry(DXA)and bioelectrical impedance analysis(BIA).SPSS 17.0 software was used for statistical analysis.Results:1.Comparison of data between obese group and non-obese groupThere were no significant differences between the two groups in age,height,blood calcium,blood phosphorous,AKP,LDL-C,UA,parathyroid hormone(PTH),25-hydroxy vitamin D,N-terminal osteocalcin(N-MIDOs),β-CROSS,total type I collagen amino terminal prolongation peptide(T-P1NP),fat-free body weight and muscle mass.In obese group,the weight,BMI,TG,hip BMD(femoral neck,trochanter,internal,summation),lumbar BMD(L1,L2,L3,L4,L1-L4summation),inorganic salt,subcutaneous fat mass,visceral fat mass,visceral fat area(VFA),body fat,body fat rate,and waist hip ratio were higher than those of non-obese group.2.Pearson correlation analysis of BMD and body componentsThere was a positive correlation between the BMD of femoral neck and total of hip joint BMD,L2 BMD,the sum of L1-L4 BMD with fat free body weight,inorganic salt,muscle volume,subcutaneous fat mass,visceral fat mass,skeletal muscle volume and body fat mass.The sum of hip joint BMD,L2 BMD and the sum of L1-L4 BMD were positively correlated with waist hip ratio.3.Pearson correlation Analysis of BMD and Bone Metabolism markersThere was no significant correlation between femoral neck BMD,total hip joint BMD,L2 BMD,the sum of L1-L4 BMD,25-hydroxy vitamin D,p-CROSS,and T-PINP.4.Correlation Analysis between BMD and General Clinical Indexes(1)BMD in femoral neck was positively correlated with height,body weight,and BMI.(2)The sum of hip joint BMD was positively correlated with height,body weight and BMI.(3)There was a significant positive correlation between L2 BMD,body weight and BMI.(4)There was a significant positive correlation between the sum of L1-L4 BMD,body weight and BMI.(5)There was no significant correlation between femoral neck BMD,total hip joint BMD,L2 BMD,the sum of L1-L4 BMD with serum calcium,blood phosphorous,AKP,TG,LDL-C and UA.5.Multiple linear regression analysis of bone mineral density,body composition and bone metabolism markers(1)The dependent variable of femoral neck BMD,age,25-hydroxy vitamin D,β-CROSS,T-P1NP,fat-free body weight,inorganic salt,subcutaneous fat mass,visceral fat mass,body fat rate,skeletal muscle volume and VFA were independent variables.Multivariate linear regression analysis was carried out that the BMD of the neck of the femur is independent with25-hydroxy vitamin D,visceral fat mass and VFA.(2)Taking total BMD of hip as dependent variable,age,25-hydroxy vitamin D,β-CROSS,T-P1NP,fat-free body weight,inorganic salt,subcutaneous fat mass,visceral fat mass,body fat rate and skeletal muscle volume as independent variables,multivariate linear regression analysis was carried out that:total BMD in hip was independently correlated with 25-hydroxy vitamin D and VFA.(3)With L2 BMD as dependent variable,age,25-hydroxy vitamin D,β-CROSS,T-P1NP,fat-free body weight,inorganic salt,subcutaneous fat mass,visceral fat mass,body fat rate and skeletal muscle volume as independent variables,multivariate linear regression analysis was carried out that L2 BMD is independent with 25-hydroxy vitamin D and VFA.(4)Using the sum of L1-L4 BMD as dependent variable,age,25-hydroxy vitamin D,β-CROSS,T-P1NP,fat-free body weight,inorganic salt,subcutaneous fat mass,visceral fat mass,body fat rate and skeletal muscle volume were used as independent variables,multivariate linear regression analysis was carried out that:the sum of L1-L4 BMD,age,25-hydroxyvitamin D,β-CROSS,skeletal muscle volume are independent correlation.Conclusions:1.Compared with non-obese subjects,the weight,BMI,TG,hip BMD(femoral neck,trochanter,internal,summation),lumbar BMD(L1,L2,L3,L4,L1-L4 summation),inorganic salt,subcutaneous fat mass,visceral fat mass,VFA,body fat mass,body fat rate,waist-hip ratio were higher than those of non-obese patients.2.There was an independent correlation between femoral neck BMD,25-hydroxy vitamin D,visceral fat mass and VFA.Total BMD of hip was independent correlated with VFA and 25-hydroxy vitamin D in elderly obese subjects.L2 BMD was independent correlation with age,25-hydroxy vitamin D and VFA.The sum of L1-L4 BMD was independent correlation with age,25-hydroxy vitamin D,P-CROSS,and skeletal muscle volume.Age,25-hydroxy vitamin D,visceral fat and skeletal muscle were independent risk factors for BMD.Proper supplementation of vitamin D,keeping a reasonable distribution of body fat and increasing the amount of skeletal muscle will help to improve the BMD of the elderly obese person.