High bone mass in a female Hutterite population.

We examined a Hutterite population (n = 243) to determine if their agriculturally diverse, self-sufficient communal lifestyle promotes optimal bone mass attainment because of adequate calcium intake and high physical activity levels during growth and young adulthood. We measured total body (TB) and lumbar bone mineral content (BMC) and bone mineral density (BMD) in 39 school-age (younger) females and 204 working (older) females. Forty-five percent of older females and 79% of younger females currently consumed > or = 3 servings (svg) of dairy per day. Older females had lumbar (0.6 +/- 1.3) and TB (1.1 +/- 1.1) BMD Z scores greater than 0 (both, p < 0.001). The lumbar BMD Z score of younger females was not different from 0 (-0.1 +/- 1.0; p = 0.5). Both lumbar (r = 0.46; p < 0.001) and TB (r = 0.20; p = 0.02) BMD Z scores increased with increasing age. In multiple regression analyses for older females, lumbar bone area (p < 0.001), weight (p < 0.001), current hours on feet per day (p = 0.01), colony workload (p < 0.01), and estrogen status (p = 0.06) predicted lumbar BMC. TB bone area (p < 0.001), current hours on feet per day (p < 0.001), and colony workload (p < 0.01) predicted TB BMC. For younger females, lumbar bone area (p < 0.001), weight (p < 0.01), years in present colony (p = 0.02), and menses (p < 0.001) predicted lumbar BMC. TB bone area (p < 0.001), height (p < 0.01), years in present colony (p = 0.03), and menses (p < 0.01) predicted TB BMC. The effect of colony workload could not be separated from other factors different by colony. A heritability estimate of 0.66 was calculated for lumbar BMD using mother and daughter Z scores. Adequate calcium intake during growth, high physical activity early in life, and genetic factors may be contributing to above normal BMD levels in adult female Hutterites.     

Relationships between bone mass and circulating leptin concentrations in Hutterites

A limited number of previous studies have shown inverse associations between bone mass or density and circulating leptin in humans. Relationships between bone mass and circulating leptin in Hutterites, who have elevated bone density, are unknown. Knowledge gained from studies in mice suggests that Hutterites exhibit traits consistent with a deficiency in circulating leptin or in leptin signaling. We examined relationships between whole body (WB) and regional (lumbar, total hip, femoral neck, trochanter) bone mineral content (BMC) by dual energy X-ray absorptiometry and circulating leptin in 249 Hutterites (137 female) ages 20–55 years and 72 similarly aged non-Hutterites (37 female). We tested the hypothesis that (1) Hutterites will have low circulating leptin concentrations for a given amount of body fat compared to non-Hutterites, and (2) controlling for body fat, there will be an inverse relationship between BMC and circulating leptin among Hutterites.

Hutterites had higher BMC than non-Hutterites at all skeletal sites after adjusting for site-specific bone area, age, and sex (P ≤ 0.02). Hutterite females had higher leptin concentrations than non-Hutterite females [geometric mean and 95% confidence interval (CI): 18.38 (17.18, 19.67) vs. 14.30 (12.55, 16.28), P ≤ 0.001) after adjusting for WB fat mass. Hutterite males also had higher leptin concentrations than non-Hutterite males [geometric mean and 95% CI: 6.53 (6.11, 6.98) vs. 5.62 (4.98, 6.35), P = 0.03) after adjusting for WB fat mass.

We used backward stepwise regression to determine significant (P ≤ 0.10) covariates to include in models predicting WB and regional BMC among Hutterites (separately by sex). Subsequently, we entered leptin (log-transformed) to models to test for significance (P ≤ 0.05). After adjusting for covariates, leptin concentration was not a significant predictor of BMC at any site, in either sex, among Hutterites. It is possible that genetic influences that interfere with hypothalamic leptin signaling, in a manner unrelated to adipocyte leptin production, contribute to elevated Hutterite bone density.     

Rural versus nonrural differences in BMC, volumetric BMD, and bone size: a population-based cross-sectional study

Despite reports of lower fracture risk among rural versus urban populations, few studies have investigated rural versus urban differences in bone mineral content (BMC) and bone mineral density (BMD). Population differences in cross-sectional bone geometry and understanding lifestyle factors responsible for these differences may reveal insights into the reason for differences in fracture risk. We hypothesized that if lifestyle differences in bone mass, size, and geometry are a result of muscle strength, activity, or dietary differences, Hutterite and rural populations should have greater bone mass compared to nonrural populations. The study population consisted of 1189 individuals: 504 rural Hutterites (188 men), 349 rural individuals (>75% life farming, 184 men), and 336 nonrural individuals (never lived on farm, 134 men) aged 20 to 66 years. BMC, bone area, and areal BMD (aBMD) of the total body (TB), hip, femoral neck (FN), and spine by DXA; volumetric BMD (vBMD) and bone geometry at the 4% and 20% radius; polar stress strain index (pSSI), a measure of bone strength, at the 20% pQCT site; and strength, 7-day activity recall, and 24-h diet recall were collected and compared among groups. Hutterite women and men had greater grip strength compared to rural and nonrural populations (both, P < 0.001). Rural women had greater activity versus Hutterite and nonrural (P < 0.001), while both Hutterite and rural men had greater activity than nonrural (P < 0.001). Hutterite and rural populations tended to have greater BMC and areal size than the nonrural population, while Hutterites had greater BMC and areal size than rural population at some (TB, FN for females only), but not all (proximal hip), sites. Cortical vBMD was inversely associated with periosteal circumference at the 20% radius in women (r = −0.25, P < 0.001) and men (r = −0.28, P < 0.001) and was higher in nonrural versus Hutterite and rural men. Hutterite and rural women and men had greater pSSI at the 20% radius compared to nonrural; inclusion of strength measurements explained population differences among women, but not men. Lifestyle differences did not explain population differences in BMC, aBMD, vBMD, or bone size.     

Interpretation of whole body dual energy X-ray absorptiometry measures in children: comparison with peripheral quantitative computed tomography

The assessment of bone health in children requires strategies to minimize the confounding effects of bone size on dual energy X-ray absorptiometry (DXA) areal bone mineral density (BMD) results. Cortical bone composes 80% of the total skeletal bone mass. The objective of this study was to develop analytic strategies for the assessment of whole body DXA that describe the biomechanical characteristics of cortical bone across a wide range of body sizes using peripheral quantitative computed tomography (pQCT) measures of cortical geometry, density (mg/mm³), and strength as the gold standard. Whole body DXA (Hologic QDR 4500) and pQCT (Stratec XCT-2000) of the tibia diaphysis were completed in 150 healthy children 6–21 years of age. To assess DXA and pQCT measures relative to age, body size, and bone size, gender-specific regression models were used to establish z scores for DXA bone mineral content (BMC) for age, areal BMD for age, bone area for height, bone area for lean mass, BMC for height, BMC for lean mass, and BMC for bone area; and for pQCT, bone cross-sectional area (CSA) for tibia length and bone strength (stress-strain index, SSI) for tibia length. DXA bone area for height and BMC for height were both strongly and positively associated with pQCT CSA for length and with SSI for length (all P < 0.0001), suggesting that decreases in DXA bone area for height or DXA BMC for height represent narrower bones with less resistance to bending. DXA BMC for age (P < 0.01) and areal BMD (P < 0.05) for age were moderately correlated with strength. Neither DXA bone area for lean mass nor BMC for lean mass correlated with pQCT CSA for length or SSI for length. DXA BMC for bone area was weakly associated with pQCT SSI for length, in females only. Therefore, normalizing whole body DXA bone area for height and BMC for height provided the best measures of bone dimensions and strength. DXA BMC normalized for bone area and lean mass were poor indicators of bone strength.     

Leisure-time physical activity and rate of bone loss among peri- and postmenopausal women: a longitudinal study.

We examined the association between continuous leisure-time physical activity and the change in bone mineral density (BMD) and bone mineral content (BMC) in a population-based random sample of 1873 peri- and postmenopausal women. Leisure-time physical activities were registered with self-administered questionnaires in 1989 and 1994, and with an assisted questionnaire in 1995-1997. BMD and BMC were measured from lumbar vertebrae L2-4 and left femoral neck using dual-energy X-ray absorptiometry (DXA) in 1989-1991 and 1994-1997. During the average 5.6 year follow-up, annual loss of lumbar BMC was 124 mg (311 vs. 435 mg, p = 0.036) and annual loss of lumbar BMD was 1.22 mg/cm(2) (4.15 vs. 5.37 mg/cm(2), p = 0.21) smaller among women with regular (at least 1 h each week) weight-bearing leisure-time exercise compared with sedentary women. The advantage was even larger in women with walking or jogging as their only regular weight-bearing leisure-time exercise; that is, their annual loss of lumbar BMC was 180 mg (272 vs. 452 mg, p = 0.022), and annual loss of lumbar BMD was 2.78 mg/cm(2) (2.96 vs. 5.74 mg/cm(2), p = 0.029) smaller than in sedentary women. Continuous leisure-time physical activity did not have any association with loss of BMC or BMD in the femoral neck Physical activity during 12 months before the last bone densitometry was not associated with loss of BMC or BMD at any site. Our results suggest that regular weight-bearing exercise diminishes lumbar bone loss, but might be ineffective in the prevention of femoral osteoporosis among peri- and early postmenopausal women.     

Bone densitometry: which skeletal sites are best predicted by bone mass determinants?

Evaluation of bone mineral content/bone mass density (BMC/BMD) is important to determine bone mass development among adolescents in health and disease. It is uncertain at which skeletal site BMC/BMD is best predicted by bone mass determinants. On the other hand, intrapersonal BMC/BMD data can be clustered into a composite index score to facilitate correlation and outcome prediction analysis. This study aimed to identify the skeletal site that was best predicted by bone mass determinants and to develop a composite index score based on multisite BMC/BMD values in healthy adolescent girls. Eleven BMD/BMC variables per subject were evaluated by using dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) in 236 healthy girls aged 12–15 years. Bone mass determinants, namely, weight, height, puberty, dietary calcium, physical activity, and bone turnover markers, were determined. Factor analysis was used to develop composite index scores that summarized characteristics of multisite BMC/BMD. Results showed that lumbar spinal BMD and BMC (by DXA) and tibial integral BMD (by pQCT) were the BMC/BMD sites better predicted by bone mass determinants (R ², 0.57–0.77) in multiple regression analysis. On the other hand, three composite index scores representing areal BMD, areal BMC, and vBMD were derived to summarize the original BMC/BMD values. The composite index scores had similar predicting power (R ², 0.419–0.749) compared to those of original BMC/BMD, indicating that the composite index scores were representative of the original variables. To conclude, lumbar spinal BMD and BMC and tibial integral BMD were the three BMC/BMD variables better predicted by bone mass determinants. This evaluation would help select appropriate skeletal sites as outcome measures for bone mass evaluation in future studies. Also, the development of composite index scores could help reduce the number of variables for correlation and outcome prediction analyses.     

Simulated change in body fatness affects Hologic QDR 4500A whole body and central DXA bone measures.

Changes in body fatness may impact the accuracy of dual energy X-ray absorptiometry (DXA) measures of bone mineral content (BMC) and bone mineral density (BMD). The aim of this study was to determine if DXA can accurately assess BMC and BMD with changes in exogenous fat (lard) placed to simulate weight change. Whole body (WB), lumbar spine (LS), and proximal femur (PF) DXA scans (Hologic QDR 4500A) were performed on 30 elderly (52-83 yr) and 60 young (18-40 yr) individuals (i.e., 45 females and 45 males) of varying body mass index (mean+/-standard deviation: 26.1+/-4.9 kg/m2). When scans were repeated with lard packets (2.54 cm thick, 25.4x17.8 cm, 1 kg), WB BMD decreased 1.1% and 1.6% after chest and thigh packet placement, respectively (p=0.001), PF BMD increased 0.7% (p=0.02) and LS BMD decreased 1.6% (p=0.001) primarily due to a 2.2% reduction in LS BMC (p<0.001). Initial LS BMC and trunk mass were related to error in LS BMC measures due to lard-loading (r=0.64 and 0.45, respectively, p<0.001). We conclude that on average simulated weight change minimally impacts PF bone measures and moderately impacts WB and LS bone measures; however, individual variability in measurement error was noteworthy and may be impacted by body thickness.     

A comparison of radial peripheral quantitative computed tomography, calcaneal ultrasound, and axial dual energy X-ray absorptiometry measurements in women aged 45-55 yr.

Perimenopausal bone loss is considered to affect trabecular bone preferentially. Peripheral quantitative computed tomography (pQCT) quantifies trabecular bone mineral density (BMD) independently at the ultradistal radius. This article examines differences in pQCT BMD between late premenopausal and early postmenopausal women, comparing the differences with calcaneal ultrasound and axial dual energy X-ray absorptiometry measurements. One hundred nineteen normal perimenopausal women aged 45-55 yr who attended a randomized osteoporosis screening program were stratified by menopausal status into premenopausal (PRE: n = 79) and postmenopausal (POST: n = 40) groups. All measurements were lower in the postmenopausal group with the exception of ultrasonic velocity (PRE vs POST: 1397 +/- 53.8 vs 1421 +/- 58.5 m/s, p = 0.037). Total (391.8 +/- 52.9 vs 366.3 +/- 68.6 g/cm(3), p = 0.013) and subcortical (533.6 +/- 59.4 vs 504.3 +/- 79.8 g/cm(3) p = 0.018), but not trabecular (187.5 +/- 38.8 vs 173.2 +/- 46.6 g/cm(3), p = 0. 098) or cortical (561 +/- 53.4 vs 551.2 +/- 66 g/cm(3), p = 0.174), pQCT BMD measurements were significantly lower in the POST group, as were ultrasonic attenuation (79.4 +/- 16 vs 72.3 +/- 18.0 dB/Mz, p = 0.034), DXA spine (1.032 +/-16 vs 0.959 +/- 0.2 g/cm(2), p = 0.003), and all hip (p 相似文献   

应用pQCT与DXA定量检测去卵巢大鼠股骨近端骨质疏松建模效果的对比研究

目的比较pQCT与DXA定量检测去卵巢大鼠股骨近端骨质疏松的建模效果的能力。方法16只8月龄Wistar雌性大鼠(平均体重350g)随机分为模型组(卵巢切除组)与对照组(卵巢假切除组)。术后3个月,取大鼠左侧股骨。应用肢体计算机断层扫描(pQCT)与双能X线骨密度仪(DXA)对骨质疏松建模效果进行对比研究:(1)确定pQCT与DXA测量精度,即计算重复测量的精度误差;(2)比较应用两种骨密度仪所测得的对照组、模型组的骨密度、骨矿含量、骨几何结构参数及其相关系数。结果(1)pQCT总骨及松质骨体密度的测量精度误差分别为2.27%与2.00%,而DXA骨面密度的测量精度误差为3.36%。(2)模型组pQCT总骨体密度和松质骨体密度分别低于对照组8.2%和15.0%犤(模型组-对照组)/对照组×100%犦,差异有显著性(P<0.01);而模型组DXA骨面密度低于对照组3.0%,差异无显著性(P>0.05)。模型组pQCT总骨骨矿含量低于对照组3.7%,差异无显著性(P>0.05),而松质骨骨矿含量低于对照组11.4%,差异有显著性(P<0.05);模型组DXA骨矿含量低于对照组3.0%,差异无显著性(P>0.05)。(3)DXA骨矿含量与pQCT总骨骨矿含量之间呈正相关(r=0.82,P<0.001);DXA骨投影面积与pQCT骨体积之间亦呈正相关(r=0.52,P<0.05);DXA骨面密度与pQCT总骨体密度之间无相关关系(r=0.14,P>0.05)。DXA     

Bone mineral density and body composition in men with systemic lupus erythematosus: a case control study

OBJECTIVE: To study the bone mineral density (BMD) and body composition in men with systemic lupus erythematosus (SLE). METHODS: Consecutive male patients who fulfilled > or =4 ACR criteria for SLE and age-matched healthy men were recruited for measurement of BMD and body composition by DXA scan. Risk factors for low BMD in SLE patients were evaluated. RESULTS: 40 male SLE patients were studied (age 42.6+/-12 years; disease duration 84.7+/-79 months). 34 (85%) patients were treated with long-term glucocorticoids. Compared with 40 controls, SLE patients had a significantly lower BMD at the lumbar spine (0.96+/-0.16 vs 1.03+/-0.11 g/cm2; p=0.02) and the hip (0.87+/-0.14 vs 0.94+/-0.12 g/cm2; p=0.04). At the spine, 12 (30%) SLE patients had Z scores< - 2.0 and 2 (5%) had osteoporotic fractures. At the hip, 3 (7.5%) patients had Z scores< - 2.0 but none had hip fractures. The BMD Z scores at the femoral neck and spine were significantly lower in SLE patients than controls. The total lean body mass was also lower in patients than control subjects (46.4+/-7.3 vs 50.5+/-5.9 kg; p=0.01). Multiple regression revealed increasing age, habitual drinking, lower BMI and use of high-dose prednisolone were unfavorably associated with lower BMD at the spine in SLE patients. CONCLUSIONS: Reduced BMD and lean body mass are prevalent in men with SLE. Appropriate measures against osteoporosis should be undertaken, especially in older patients with low BMI who receive high-dose glucocorticoids.     

Bone mineral density by age, gender, pubertal stages, and socioeconomic status in healthy Lebanese children and adolescents

Gender, ethnicity, and lifestyle factors affect bone mass acquisition during childhood, thus the need for age- and sex-adjusted Z scores using ethnic-specific data for bone mineral density (BMD) measurement. This study aimed at establishing normative data for BMD in healthy Lebanese children and adolescents. Three hundred sixty-three healthy children aged 10 to 17 years (mean+/-SD: 13.1+/-2.0) were studied. BMD, bone mineral content (BMC), and lean mass were measured by dual-energy X-ray absorptiometry (DXA) using a Hologic 4500A device, and apparent volumetric BMD (BMAD) of the lumbar spine and the femoral neck were calculated. BMD, BMC, and BMAD were expressed by age groups and Tanner stages for boys and girls separately. There was a significant effect of age and puberty on all bone parameters, except at the femoral neck BMAD in boys. BMC and BMD were higher at cortical sites in boys, including subtotal body and hip; whereas, in girls, it was higher at a site more enriched in trabecular bone, namely the lumbar spine. At several skeletal sites, girls had significantly higher BMD adjusted for lean mass than boys. By the end of puberty, adolescents had a mean BMD that was 43-66% higher at the lumbar spine and 25-41% higher at cortical sites than pre-pubertal children, depending on the gender. Mean BMD values in the study group were significantly lower (P<0.01) than Western normative values, with Z scores ranging between -0.2 and -1.1. In both genders, children of lower socioeconomic status tended to have lower BMD than those from a higher socioeconomic background. This study allows additional insight into gender dimorphism in mineral accretion during puberty. It also provides a valuable reference database for the assessment of BMD in children with pubertal or growth disorders who are of Middle Eastern origin.     

Cortical and Trabecular Bone at the Forearm Show Different Adaptation Patterns in Response to Tennis Playing

Bone responds to impact-loading activity by increasing its size and/or density. The aim of this study was to compare the magnitude and modality of the bone response between cortical and trabecular bone in the forearms of tennis players. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the ulna and radius were measured by dual-energy X-ray absorptiometry (DXA) in 57 players (24.5 +/- 5.7 yr old), at three sites: the ultradistal region (50% trabecular bone), the mid-distal regions, and third-distal (mainly cortical bone). At the ultradistal radius, the side-to-side difference in BMD was larger than in bone area (8.4 +/- 5.2% and 4.9 +/- 4.0%, respectively, p < 0.01). In the cortical sites, the asymmetry was lower (p < 0.01) in BMD than in bone area (mid-distal radius: 4.0 +/- 4.3% vs 11.7 +/- 6.8%; third-distal radius: 5.0 +/- 4.8% vs 8.4 +/- 6.2%). The asymmetry in bone area explained 33% of the variance of the asymmetry in BMC at the ultradistal radius, 66% at the mid-distal radius, and 53% at the third-distal radius. The ulna displayed similar results. Cortical and trabecular bone seem to respond differently to mechanical loading. The first one mainly increases its size, whereas the second one preferentially increases its density.     

Eating attitudes and habitual calcium intake in peripubertal girls are associated with initial bone mineral content and its change over 2 years.

This 2-year prospective study examined associations among bone mineral acquisition and physical, maturational, and lifestyle variables during the pubertal transition in healthy girls. Forty-five girls, initially 10.5+/-0.6 years, participated. Body composition and bone mineral content (BMC) at the spine and total body (TB) were assessed at baseline and annually thereafter using dual-energy X-ray absorptiometry (DXA). Nutrient intakes were assessed using 3-day diet records and a calcium food frequency questionnaire (FFQ), physical activity by questionnaire, sexual maturation using Tanner's stages of breast and pubic hair maturation, growth by height and weight, and eating attitudes using the children's Eating Attitudes Test (Children's EAT). Mean children's EAT subscale scores (dieting, oral control [OC], and bulimia) were stable over time. Median split of OC subscale scores was used to form high and low OC groups. Groups had similar body composition, dietary intake, activity, and Tanner stage at baseline and 2 years. Using height, weight, and Tanner breast stage as covariates, girls with low OC scores had greater TB BMC at baseline (1452+/-221 g vs. 1387+/-197 g; p = 0.030) and 2 years (2003+/-323 g vs. 1909+/-299 g; p = 0.049) and greater lumbar spine (LS) BMC at 2 years (45.2+/-8.8 g vs. 41.2+/-9.6 g; p = 0.042). In multiple regression analysis, OC score predicted baseline, 2 years, and 2-year change in TB and spinal BMC, contributing 0.9-7.6% to explained variance. Calcium intake predicted baseline, 2 years, and 2-year change in TB BMC, explaining 1.6-5.3% of variance. We conclude that both OC and habitual calcium intake may influence bone mineral acquisition.     

Bone mineral density in prepubertal obese and control children: relation to body weight,lean mass,and fat mass

The aim of the study was to determine the influence of obesity on bone status in prepubertal children. This study included 20 obese prepubertal children (10.7 +/- 1.2 years old) and 23 maturation-matched controls (10.9 +/- 1.1 years old). Bone mineral area, bone mineral content (BMC), bone mineral density (BMD), and calculation of bone mineral apparent density (BMAD) at the whole body and lumbar spine (L1-L4) and body composition (lean mass and fat mass) were assessed by DXA. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) at the calcaneus were measured with a BUA imaging device. Expressed as crude values, DXA measurements of BMD at all bone sites and BUA (69.30 versus 59.63 dB/MHz, P < 0.01) were higher in obese children. After adjustment for body weight and lean mass, obese children displayed lower values of whole-body BMD (0.88 versus 0.96 g/cm2, P < 0.05) and BMC (1190.98 versus 1510.24 g, P < 0.01) in comparison to controls. When results were adjusted for fat mass, there was no statistical difference between obese and control children for DXA and ultrasound results. Moreover, whole-body BMAD was lower (0.086 versus 0.099 g/cm3, P < 0.0001), whereas lumbar spine BMAD was greater (0.117 versus 0.100 g/cm3, P < 0.001) in obese children. Thus, it was observed that, in obese children, cortical and trabecular bone displayed different adaptation patterns to their higher body weight. Cortical bone seems to enhance both size and BMC and trabecular bone to enhance BMC. Finally, considering total body weight and lean mass of obese children, these skeletal responses were not sufficient to compensate for the excess load on the whole body.     

Ultrasound velocity and dual-energy X-ray absorptiometry in normal and pagetic bone

Bone affected by Paget's disease is known to be dense but more prone to fractures. It is proposed that dual-energy X-ray absorptiometry (DXA) and quantitative ultrasound (QUS) assess different aspects of the skeletal status. In this study, we used Paget's disease of the tibia as a model to explore this. Ten patients with Paget's disease affecting a single tibia were investigated with the normal side acting as the control within each individual. Tibial speed of sound (SOS) was measured at the midpoint of the affected and control tibiae using a Soundscan 2000 (Myriad Ultrasound System, Rehovot, Israel) device. Bone mineral density (BMD) of the tibia was measured at a level corresponding to the site of the tibial ultrasound using a QDR-2000+ (Hologic, Inc., Waltham, MA). The mean bone area and estimated volume in the pagetic tibia was greater than that in the normal tibia (bone area: 25.10 +/- 8.00 vs. 20.23 +/- 5.43 cm(2), p = 0.017; estimated bone volume: 68.79 +/- 41.99 vs. 43.62 +/- 22.56 cm(3), p = 0.02), reflecting the bone expansion characteristic of Paget's disease. The bone mineral content (BMC) was more markedly increased in the pagetic tibia (27.38 +/- 12.98 vs. 14.39 +/- 6.14 g, p = 0.003) and, consequently, areal bone mineral density (BMD) was also markedly increased in the pagetic bone (1.09 +/- 0.38 vs. 0.77 +/- 0.44 g/cm(2), p = 0.018). There was no significant difference in the estimated volumetric BMD between the pagetic and the normal tibia (0.48 +/- 0.24 vs. 0.47 +/- 0.51 g/cm(3), p = 0.96). In contrast, the mean tibial SOS in the leg affected by Paget's disease was significantly lower than in the unaffected leg (3228 +/- 234 vs. 3840 +/- 164 m/sec, p < 0.001). When expressed as a z score using the normal limb as reference, areal BMD was 0.72 SD higher in the affected limb, whereas tibial SOS was 3.72 SD lower. We conclude that tibial SOS detects important changes in bone quality in Paget's disease of bone, which are unrelated to calcium content.     

Age trends of bone mineral density and percentile curves in healthy Chinese children and adolescents

The clinical utility of dual-energy X-ray absorptiometry (DXA) measurement requires appropriate normative values, designed to be diverse with respect to age, gender and ethnic background. The purpose of this study was to generate age-related trends for bone density in Chinese children and adolescents, and to establish a gender-specific reference database. A total of 1,541 Chinese children and adolescents aged from 5 to 19-years were recruited from southern China. Bone mineral density (BMD), bone mineral content (BMC), and bone area (BA) were measured for the total body (TB) and total body less head (TBLH). The height-for-age, height-for-BA, and BMC-for-BA percentile curves were developed using the least mean square method. TB BMD and TBLH BMD were highly correlated. After 18 years, TB BMD was significantly higher in boys than girls. For TB BMC and TBLH BMC, gender differences were found in age groups 12 years and 16–19 years; however, the TBLH BMD was significantly different between genders >16 years. The head region accounted for 13–52 and 16–49 % of the TB BMC in boys and girls, respectively. Furthermore, the percentages were negatively correlated with age and height. This study describes a gender-specific reference database for Chinese children and adolescents aged 5–19 years. These normative values could be used for clinical assessment in this population.     

Effect of aging on trabecular and compact bone components of proximal and ultradistal radius

Bone densitometry has become a major tool for osteoporosis risk assessment. The traditional dual-energy X-ray absorptiometry (DXA) methods are able to evaluate the bone mineral content (BMC; mg/cm) and the areal density (BMD; mg/cm²), but only quantitative computed tomography (QCT) has the potential to measure the true volumetric bone density in the sense of mass per unit volume (mg/cm³). Peripheral QCT (pQCT) measurements were carried out at the non-dominant radius using a Stratec XCT 960 (Unitrem, Roma) in 241 postmenopausal and 29 premenopausal women. The sites of evaluation were both the ultradistal and the proximal radius. The technique used has a coefficient of variation of 2% and it allows separation of the bone section into trabecular and cortical bone on the basis of density threshold. Bone mass of radius, hip and spine was also evaluated by DXA procedures. The bone density data obtained by pQCT were significantly correlated with all DXA measurements. The correlation coefficients between their respective BMD values ranged from 0.48 to 0.75, but for the BMC values of the radius the correlation coefficients ranged from 0.82 to 0.93. The BMD values measured by DXA, but not by pQCT, were positively related with patient heights. All pQCT density measurements, including those obtained at the proximal radius and containing exclusively cortical bone, where negatively related with age and years since menopause. A partial volume effect, which is increasingly relevant the thinner are the bone cortices, might explain that. However, by applying increasing density thresholds, cortical bone density seems to decrease with age as a consequence of a gradual density diminution from the inner part of the bone cortex outwards. Trabecular bone density decreases with aging, but its overall mass does not change as a consequence of an age-related enlargement of trabecular area. Thus, the proportion of trabecular bone over total bone rises, and this might be relevant for our understanding of the age-related changes in bone turnover and rate of bone loss.     

Postmenopausal Women With Colles'' Fracture Have Lower Values of Bone Mineral Density Than Controls as Measured by Quantitative Ultrasound and Densitometry

Measurement of ultrasonographic parameters provides information concerning not only bone density but also bone architecture. We investigated the usefulness of ultrasonographic parameters and bone mineral density (BMD) to evaluate the probability of Colles' fracture. Two-hundred eighty-nine postmenopausal women (62.3 +/- 8.7 yr) with (n = 76) and without (n = 213) Colles' fracture were studied. BMD of lumbar spine and proximal femur was evaluated in all women by dual-energy X-ray absorptiometry (DXA) and speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness in the calcaneus were measured by a Sahara ultrasonometer (Hologic). Patients suffering from Colles' fracture had lower values of BMD adjusted by height at the lumbar spine, L2-L4 (0.797 g/cm2 vs 0.860 g/cm2), femoral neck (0.685 g/cm2 vs 0.712 g/cm2 ), SOS (1518 m/sg vs 1525 m/sg), and stiffness (74.6 vs 77.7) (p < 0.05). Nevertheless, BUA values were similar in both groups. After stepwise logistic regression analysis, the area found under receiver operating characteristic (ROC) curves was 0.60 for L2L4 and 0.63 for a formula combining L2L4 and height. Our data suggest that patients suffering from Colles' fracture have lower values of BMD by DXA, SOS, and stiffness. However, the ability of these techniques to discriminate is low because the values for the area under ROC curve are 0.60 for L2-L4 and 0.63 for a formula derived of the combination of L2-L4 and height.     

Validation and application of dual-energy X-ray absorptiometry to measure bone mineral density in rabbit vertebrae.

The rabbit could be a superior animal model to use in bone physiology studies, for the rabbit does attain true skeletal maturity. However, there are neither normative bone mineral density (BMD) data on the rabbit nor are there any validation studies on the use of dual-energy X-ray absorptiometry (DXA) to measure spinal BMD in the rabbit. Therefore, our aim was twofold: first, to investigate whether DXA could be used precisely and accurately to determine the bone mineral content (BMC). bone area (BA). and BMD of the rabbit lumbar spine: Second. to evaluate the new generation fan-beam DXA (Hologic QDR-4500) with small animal software by comparing two DXA methodologies QDR-1000 and QDR-4500 with each other, as well as against volumetric bone density (VBMD) derived from Archimedes principle. As expected. there was a magnification error in the QDR-4500 (BMC, BA. and BMD increased by 52%. 38%. and 10%, respectively, when the vertebrae were positioned flat against the scanning table). With the magnification error kept constant (vertebrae positioned 10 cm above the scanning table to match the height in vivo). there were no differences among the mean BMC. BA. and BMD of the rabbit vertebrae (Ll-L7) in vivo and in vitro using the QDR-4500 (p > 0.05). BMC, BA, and BMD differed between QDR-1000 and QDR-4500 in vitro because of a magnification error when the vertebrae were flat on the table (p <0.0001). and, consequently. the machines did not correlate with one another (p > 0.05). However, the BMC, BA, and BMD of the two DXAs did significantly correlate with each other in vivo and in vitro when the magnification error was compensated for (r = 0.44 and 0.52. i2 = 0.45 and 0.63. and 12 = 0.41 and 0.60. respectively. p < 0.05-0.008). The BMC and BMD (in vivo and in vitro) of the rabbit vertebrae measured by QDR-4500 was significantly correlated with VMBD, ash weight, and mineral content (,2 = 0.67-0.90,j <0.01-0.0001). Therefore, the QDR-4500 can be used to yield precise and accurate measurements of the rabbit spine.