Clinical Investigation And Analysis Of Risk Factors Associated With Bone Mineral Density

Objective:osteoporotic fractures are worldwide growing and important health concerns of elderly population. Reduced bone mineral density (BMD) is a major risk factor for osteoporotic fractures. Thus, the analysis of risk factors for BMD through Part I: Obesity and osteoporosis are traditionally believed as two opposite diseases, and BMI is widely believed to be positively related to bone mineral density. This traditional belief has been questioned by recent epidemiologic studies about the relation between obesity and osteoporosis. The aim of this study was to investigate the association between BMI and bone mineral density at different BMI levels, and the correlation between trunk fat percent and bone mineral density was investigated as well. Part Ⅱ:hypertension and osteoporosis are common chronic diseases among mid-elderly women, while the interaction between each other remained controversial. Our study intended to probe the relationship of hypertension and4common antihypertensives use to bone mineral density in mid-elderly women based on substantial data sample.Methods:Part I:This cross-sectional study included a total of18266subjects (8971men,9295women) who received routine physical examination at The Second Hospital Affiliated To Suzhou University between the year of2008to2013. Bone mineral density (BMD) in lumbar spine(LS) and femoral neck(FN)and trunk fat percent measurements were performed using Dual-energy X-ray absorptiometry methodology (DXA)(LUNAR DPX-NT). Initially, all the subjects were categorized into four groups:women with age below50years old, men with age below50years old, women with age above50years old and men with age above50years old. Then, subjects in each group were further divided into different BMI levels which based on two conditions:(1) Into three categories according to WHO criteria:Underweight(<18.5kg/m2), normal weight(18.5kg/m2-24.9 kg/m2) and overweight(≥25kg/m2);(2) Into7categories for each2kg/m2as a division:<19kg/m2,19.1-21kg/m2,21.1-23kg/m2,23.1-25kg/m2,25.1-27kg/m2,27.1-29kg/m2,>29kg/m2. Part II:This was a cross-sectional population-based study, a questionnaire was used to collected the general conditions (height, weight, age),drugs use, living habits of1961qualified women. All participants underwent blood pressure measurement and bone mineral density of heel bone density area was detected by quantitative ultrasonography. T-test and covariance analysis were performed to compared the difference of average BMD (bone mineral density) between groups, chi-square test and Logistic regression analyses were performed to compare the difference of the prevalence of osteoporosis between groups.Results:Part I:In the whole population, BMI was positively correlated with BMD(r=0.31for femoral neck BMD and r=0.16for lumbar spine BMD), while trunk fat percent was negatively correlated with BMD(r=-0.24for femoral neck BMD and r=-0.23for lumbar spine BMD).(1) In women and men with age above50years old:Overweight had higher average BMD value and lower risk of low BMD(T-score<-1.0) than normal weight and underweight. Nevertheless, the correlation between BMI and BMD was weak in overweight elders. Either femoral neck or lumbar spine BMD presented little variation above the BMI cut point of27kg/m2. Femoral neck and lumbar spine BMD were negatively correlated with trunk fat percent especially in overweight.(2) In women and men with age below50years old:Overweight ones had higher average BMD value but higher ratio of low BMD(Z-score<-1.0) than normal weight. The correlation between BMI and vertebrae BMD was weak. Trunk fat percent was not correlated with femoral neck BMD, but inversely correlated with lumbar spine BMD in both women and men. Part Ⅱ:The average BMD was lower in the group with hypertension than in the group without hypertension, and the average age was old in the group with hypertension. After adjustment for age, BMI, menopause, calcium intake and tea drinking, the average BMD in the group with hypertension was0.016g/cm lower than in the group without hypertension(CI-0.027--0.005,p=0.005). And among the women with hypertension, the ones not taking antihypertensive medication had0.040g/cm lower average BMD than the ones without hypertension. After adjustment for age, hypertension, the use of other antihypertensives and other factors, the average BMD was higher in the group with use of ACEI/ARB or Thiazide diuretics than in the control groups (p<0.00195%CI0.011-0.039),(p=0.001,95%CI0.014-0.053). The use of calcium channel blockers had no effect on the average BMD (p=0.80195%CI-0.015-0.019),while the average BMD in the group with β receptor inhibitors use was0.024g/cm lower than its control group (p=0.03995%CI-0.047--0.001)Conclusion:Part I:A higher BMI was not associated with higher BMD in overweight elders. Excessive trunk fat mass may partially contribute to this phenomenon. There was no gender differences in the association of BMI to BMD.Part Ⅱ:Hypertension was associated with reduced BMD in mid-elderly women. ACEI/ARB or Thiazide diuretics use presented higher BMD, while β receptor inhibitors presented lower BMD in mid-elderly women.