Site of bone density measurement may affect therapy decision

Summary The purpose of this study was to determine whether bone mineral density (BMD) measurements at the lumbar spine and femoral neck provided comparable information to women planning to use that knowledge to help them make a decision about hormone replacement therapy. Eighty-eight healthy Caucasian women, aged 44–59 and within 0 to 5 years of menopause, participated in the study. BMD measurements were performed at the lumbar spine (L1-L4) and the femoral neck by dual energy X-ray absorptiometry (DXA). Criteria suggested by the National Osteoporosis Foundation were used to categorize women as at risk for osteoporosis, bone density more than one standard deviation (SD) below the young adult mean, or as low risk, bone density at or above this level. The re that 46 women would be classified into the low risk category on the basis of spinal BMD alone. However, 28 of these 46 women would fall into the at risk category when the femoral neck BMD was measured. Sixty-one percent of women informed they were at low risk on the basis of spinal BMD would be considered at risk based on femoral neck BMD. When femoral neck BMD was used as the primary risk indicator, 14% of the women classified as low risk would be at risk if spinal BMD were added. These results suggest that both lumbar spine and proximal femur measurements should be made when women are using bone density measurements as an aid in deciding whether or not to use hormone therapy in their postmenopausal years.     

The epidemiology of fragility fractures: Is there a role for bone quality?

Fragility fractures, particularly those of the hip, vertebrae, and distal forearm, constitute a major public health problem. The two ultimate determinants of fracture are bone strength and propensity to trauma. Bone strength depends not only upon bone mass but also upon a variety of qualitative aspects of bone structure. These include its architecture, the amount of fatigue damage it has sustained, and changes in its bulk material properties, indices that are collectively subsumed into the term bone quality Fragility fractures show differences in their patterns of incidence by age, sex, ethnic group, geographic area, and season. Many of these differences are currently unexplained, and disorders of bone quality might contribute to them. There are two fracture sites at which evidence implicates bone quality more directly—the spine and proximal femur. Many vertebral compression fractures follow minimal trauma, and controlled studies suggest that vertebral microarchitecture contributes to fracture risk independently of vertebral bone mass. At the hip, observational studies have pointed to a role for disordered trabecular architecture, accumulation of microfractures (fatigue damage), and the accumulation of osteoid. The extent to which these phenomena act independently of bone mass, however, remains uncertain.Presented at the NIA Workshop on Aging and Bone Quality, September 3–4, 1992, Bethesda, Maryland     

The contribution of bone loss to postmenopausal osteoporosis

We have addressed the relative importance of peak bone mass and subsequent rate of loss in determining postmenopausal women's bone mass in old age, by examining longitudinal measurements of radial mid-shaft bone mass on various samples of healthy white postmenopausal women. Using both the variance estimate of age-specific rates of bone loss and the population variance in bone mass, we determined that rates of loss could contribute importantly to future bone mass. However, since we found a small negative correlation between initial bone mass and rate of loss, it was necessary to estimate the effect of bone loss as the complement of the contribution of initial bone mass. We found that the influence of bone loss (relative to initial bone mass) increases as the women age, such that by about age 70, the contribution of initial bone mass and rate of loss approached equality. However, estimated rates of bone loss were not very stable over time, so it was difficult to identify long-term fast-losers. We conclude that the rate of postmenopausal bone loss is an important contributor to osteoporosis at old age, but it is difficult to identify long-term fast-losers, thereby reducing the clinical value of assessments of rates of change in bone mass early in the postmenopause.     

脱脂豆粉对去卵巢大鼠骨质量的保护作用

目的 探讨脱脂豆粉对去卵巢大鼠骨质量减低的预防作用。方法 ３０只３月龄ＳＤ大鼠随机分为３组：假手术（ｓｈａｍ,Ｓ）组、脱脂粉（ｌｉｐｉｄ－ｆｒｅｅ ｓｏｙ ｐｏｗｄｅｒ,ＳＰ）组和酪蛋白（ｃａｓｅｉｎ,Ｃ）组。８周后测骨密度（ＢＭＤ）等指标。结果 ①ＳＰ组的腰椎ＢＭＤ低于Ｓ组（Ｐ〈０．０５）,股骨ＢＭＤ与Ｓ组无差异,两者均高于Ｃ组（Ｐ均〈０．０５）。②ＳＰ组腰椎的抗压强底低于Ｓ组（Ｐ〈０．０１）,股骨的抗弯强度与Ｓ组无差异,两者均高于Ｃ组（Ｐ均〈０．０１）。③ＳＰ组和Ｃ组的子宫重量均代于Ｓ组（Ｐ均〈０．０５）。结论 脱脂豆粉可以预防去卵巢大鼠股骨及部分预防其腰椎骨质量的降低,对子宫无不良影响。     

阿法骨化醇对去卵巢大鼠骨质疏松症防治作用的实验研究

目的 探讨从骨量、骨结构、骨力学和骨转换等方面研究阿法骨化醇对去卵巢大鼠骨质疏松症的防治作用。方法 ５３只健康雌性未交配６个月龄Ｗｉｓｔａｒ大鼠分为６组（１）基线组（Ｂａｓｅ）６个月龄时处死;（２）假手术组（Ｓｈａｍ）;（３）去卵巢（ＯＶＸ）治疗前对照组（ＯＶＸｂ）;（４）ＯＶＸ治疗末对照组（ＯＶＸｅ）;（５）ＯＶＸ后雌激素治疗组（Ｏ＋Ｅ）;（６）ＯＶＸ后阿法骨化醇治疗组（Ｏ＋ＶＤ）ＯＶＸ后６周开     

2型糖尿病与钙,磷代谢及相关激素的关系

目的 观察２型糖尿病患者钙、磷代谢及相关激素的变化及对骨代谢的影响。方法 测定２０例健康对照者和６０例２型糖尿病患者血甲状旁腺素（ＰＴＨ）、降钙素（ＣＴ）、２５羟维生素Ｄ３「「２５（ＯＨ）Ｄ３」」、环磷酸腺苷（ｃＡＭＰ）和血、尿钙（Ｃａ）、磷（Ｐ）、镁（Ｍｇ）,糖基化血红蛋白（ＨｂＡｌｃ）、２４ｈ尿和２４ｈ尿白蛋白定量等指标。结果 ２型糖尿病患者血ＰＴＨ水平显著高于对照组（Ｐ〈０．０１）,ＣＴ水平     

老年糖尿病患者骨质疏松及骨折发生率分析

目的：探讨２型糖尿病患者骨密度改变及骨折发生率。方法：逆向随机选取住院骨折病人３８０例,测定骨密度改变,同时测定其血Ｃａ,Ｐ,ＡＫＰ,ＧＬＵ,ＢＧＰ浓度,并统计其中糖尿病的发生率及测定值对比情况。结果;骨折病人中的糖尿病患者机率为６．３２％,骨折病人的骨密度改变在糖尿病组和非糖尿病组病人中有显著差异,和本区普查结果无显著差异。结论：糖尿病病人的骨折发生率和非糖尿病患者及无明显差异,但骨密度改变有明     

Precision and intersite correlation of bone densitometry at the radius, tibia and femur with peripheral quantitative CT

Objective. To compare the in situ precision of peripheral quantitative CT (pQCT) at the radius, tibia and femur, and to analyze the intersite correlation, in order to determine whether measurements at the lower extremity reproduce results at the radius or are of additional informative value. Design and material. pQCT measurements were performed in 86 elderly cadavers (mean age 80.5 years) at trabecular and cortical locations in the radius, tibia and femur, determining densitometric (bone mineral content and density) as well as geometric parameters (cross-sectional area, cortical thickness, polar moment of inertia and others). In 14 cadavers, repeated measurements were obtained at all sites on four different days. Results and conclusions. At cortical sites, the precision for the densitometric and geometric variables ranged from 0.4% to 4.3%, and was similar for the radius, tibia and femur. At trabecular locations, the reproducibility of the density measurements ranged from 1.8% to 2.5% at the radius, and from 3.2% to 5.9% at the femur and tibia. The intersite correlation of the total bone mineral content ranged from 0.87 and 0.97 at cortical sites, and from 0.63 to 0.85 at trabecular locations. The trabecular density showed a higher similarity between the tibia and femur (r=0.68–0.78) than between the radius and the lower extremity (r=0.41–0.45). The results demonstrate a substantial heterogeneity of trabecular bone in elderly individuals and advocate measurements directly at the site of clinical or scientific interest. Received: 5 July 1999 Revision requested: 12 August 1999 Revision received: 31 August 1999 Accepted: 13 September 1999     

Bone Mineral Density and Androgen Levels in Elderly Males

To clarify the relationship of sex male hormones and bone in men, we studied in 140 healthy elderly men (aged 55–90 years) the relation between serum levels of androgens and related sex hormones, bone mineral density (BMD) at different sites, and other parameters related to bone metabolism. Our results show a slight decrease of serum-free testosterone with age, with an increase of follicle stimulating hormone (FSH) and luteinizing hormone (LH) in a third of the elderly subjects studied. BMD decreased significantly with age in all regions studied, except in the lumbar spine. We found a positive correlation between body mass index (BMI) and BMD at the lumbar spine and femoral neck (P < 0.001). No relationship was found (uni- and multivariate regression analysis) between serum androgens or sex hormone-binding globulin (SHBG) and BMD. We found a positive correlation of vitamin D binding protein (DBP) and osteocalcin with lumbar spine BMD and with BMI, DBP, IGF-1, and PTH with femoral neck BMD. In conclusion, there is a slight decline in free testosterone and BMD in the healthy elderly males. However, sex male hormones are not correlated to the decrease in hip BMD. Other age-related factors must be associated with bone loss in elderly males. Received: 29 April 1997 / Accepted: 9 November 1997