Clinical determination of bone quality: is ultrasound an answer?

Bone mass and bone resorption in postmenopausal women with type 2 diabetes mellitus

The aim of the present study was to examine the relationships between bone mass or bone resorption evaluated by urinary cross-linked N-telopeptides of type I collagen (NTx) concentration and known and potential contributors to bone mass or bone resorption such as sex hormones, age, duration of diabetes, glycemic control (hemoglobin A(1c) [HbA(1c)]), body mass index (BMI), severity of diabetic complications, smoking status, and current treatment of diabetes in postmenopausal women with type 2 diabetes mellitus (n = 196). In addition, the relationship of bone mass to pulse wave velocity, which is an earlier indicator of cardiovascular disease, was investigated in a subgroup of patients (n = 120). Bone mass was evaluated by the quantitative ultrasound method. A higher stiffness index indicates higher bone mass. Inverse correlations were found between the stiffness index and age (r = -0.374, P < .0001) and between the stiffness index and log (urinary albumin excretion) (r = -0.170, P = .0398), and a positive correlation was found between the stiffness index and serum dehydroepiandrosterone sulfate (DHEA-S) concentration (r = 0.201, P = .0136). No significant correlations were found between the stiffness index and duration of diabetes, HbA(1c), BMI, or serum estradiol concentration. No significant correlations were found between urinary NTx concentration and age, duration of diabetes, HbA(1c), BMI, serum estradiol concentration, or serum DHEA-S concentration. The stiffness index correlated inversely with urinary NTx concentration (r = -0.262, P = .0002). No significant correlation was found between the stiffness index and pulse wave velocity (r = -0.165, P = .0714). Multiple regression analysis demonstrated that serum DHEA-S concentration was an independent determinant of the stiffness index (beta = .207, P = .0428). In conclusion, serum DHEA-S concentration correlated positively with bone mass, whereas glycemic control, BMI, or duration of diabetes did not correlate with bone mass or urinary NTx concentration in postmenopausal women with type 2 diabetes mellitus.

Peripheral bone status in rheumatoid arthritis evaluated by digital X-ray radiogrammetry and compared with multisite quantitative ultrasound

The development of secondary osteoporosis in rheumatoid arthritis (RA) has recently become well recognized, characterized by demineralization at axial and in particular periarticular peripheral bone sites. Our aim was to evaluate multisite quantitative ultrasound (QUS) compared to digital X-ray radiogrammetry (DXR) by the quantification of cortical bone loss dependent on the severity of RA. Fifty-three patients with verified RA underwent QUS measurements (Sunlight Omnisense 7000) with estimation of the speed of sound (QUS-SOS) at the distal radius and at the phalanx of the third digit. Also, bone mineral density (DXR-BMD) and metacarpal index (DXR-MCI) were estimated on metacarpals II-IV using DXR technology. Additionally, Larsen score and Steinbroker stage were assessed. Disease activity of RA was estimated by disease activity score 28 (DAS 28). For the group with minor disease activity (3.2 <or= DAS <or= 5.1), QUS-SOS (phalanx) showed a significant association to DXR-BMD (R = 0.66) and DXR-MCI (R = 0.52). In the case of accentuated disease activity (DAS > 5.1), QUS-SOS of the radius revealed a significant correlation to DXR-BMD (R = 0.71) and DXR-MCI (R = 0.84), whereas for QUS-SOS (phalanx) no significant association to the DXR parameters was shown. The DXR parameters and, to a lesser extent, the QUS data also demonstrated pronounced declines in the case of accentuated disease activity (DAS > 5.1). Both DXR-BMD (-25.9 %, P < 0.01) and DXR-MCI (-38.6 %, P < 0.01) revealed a notable reduction dependent on the severity of RA. Otherwise, QUS-SOS marginally decreased, with -2.6% (radius) and -3.9% (phalanx). DXR revealed a significant reduction of DXR-BMD as well as DXR-MCI dependent on the severity of RA and surpassed multisite QUS as a promising diagnostic tool.

Quantitative ultrasound of the calcaneus in a Korean population: reference data and relationship to bone mineral density determined by peripheral dual X-ray absorptiometry

The aim of this study was to establish reference data for the quantitative ultrasound (QUS) of the calcaneus and for the bone mineral densities (BMD) of the calcaneus and distal forearm, and to evaluate the correlation between QUS parameters and BMD in a Korean population. We performed a cross-sectional study involving 3,053 subjects (1,225 men and 1,828 women). QUS was conducted on the calcaneus and was quantified as speed of sound (SOS, m/sec), broadband ultrasound attenuation (BUA, dB/MHz), and stiffness index. The BMD of the calcaneus and distal forearm were measured using dual X-ray absorptiometry. The peak mean values for the QUS parameters occurred in the 20 to 29-yr-old subjects of both sexes, with the exception of the BUA, which reached the highest values in women of 30-39 yr. For both sexes, the mean BMD of the calcaneus was highest in those 20-29 yr old and that of the distal forearm was highest in those 40-49 yr old. The correlations between the QUS and BMD results were found to be 0.41 to 0.73 in men and 0.51 to 0.76 in women. Theses data can serve as a reference values for both sexes in Korea.

Ability of ultrasound bone profile score (UBPS) to discriminate between fractured and not fractured osteoporotic women

In this study, we evaluated the ability of different quantitative ultrasound (QUS) parameters (speed of sound, SOS, coefficient of variation, CV, = 0.34% and broadband ultrasound (US) attenuation, BUA, CV = 3.25% measured at the heel by an Hologic Sahara unit; Ad-Sos and ultrasound bone profile score (UBPS) at the proximal phalanges by an Igea DBM Sonic 1200 unit, Ad-Sos CV = 0.57%) to detect differences between osteoporotic patients with vertebral fractures and osteoporotic patients without fractures. We examined 87 women with primary osteoporosis: 53 women with femoral neck bone mineral density (BMD) T scores less than -2.5 SD and no vertebral fractures and 34 women with one or more vertebral fractures, regardless of T score values. Considering all the patients together, the correlations between QUS parameters and BMD resulted in statistical significance (p < 0.05) only for BUA and femoral neck BMD. Lumbar and femoral neck BMD did not statistically differ between the two groups, while UBPS, which is a quality control of measurement and is correlated with bone quality, was significantly higher in women without fractures than those with fractures; the other QUS parameters were not statistically different. Our data indicate that, among QUS parameters, only UBPS is able to detect differences among osteoporotic patients with and without vertebral fractures.

The use of tonebursts as an alternative to broadband signals in the measurement of speed of sound in human cancellous bone

Speed of sound (SOS) measurements, typically made using 1 MHz broadband pulses, are increasingly used in the clinical diagnosis of bone disorders. Previous in vitro studies indicate that broadband ultrasound pulses are susceptible to distortion in cancellous bone, leading to imprecise arrival time and SOS measurements. We investigated the effect of bandwidth and frequency on SOS by comparing measurements made using 1 MHz broadband with 1 MHz and 300 kHz narrowband toneburst signals in 15 human proximal femur cancellous bone specimens. There was no significant difference in the value of SOS measured from the leading edge of 1 MHz broadband, 1 MHz toneburst and 300 kHz toneburst signals. Values of SOS in later regions of 1 MHz and 300 kHz tonebursts fell significantly (p < 0.001) when compared to earlier regions. This decrease in SOS levelled off by the third complete cycle of 300 kHz toneburst signals, reaching a plateau value of 1961 +/- 239 m s-1. No plateau SOS value was obtained in 1 MHz tonebursts. The reproducibility of SOS, as measured by the coefficient of variation, was higher for later regions of 300 kHz tonebursts than for the leading edge of 300 kHz toneburst and 1 MHz broadband signals (p < 0.005). The correlation between ultrasound measured modulus and compressive Young's modulus improved when 300 kHz tonebursts (r2 = 0.83) rather than 1 MHz broadband (r2 = 0.77) signals were used to calculate SOS. The improved SOS reproducibility of later regions 300 kHz tonebursts suggest that it may be beneficial to use such signals rather than 1 MHz broadband pulses in SOS measurement. Since no reliable SOS measurements could be obtained from any region of 1 MHz tonebursts, the use of high frequency toneburst signals in cancellous bone has little value.

Recent progress in understanding the genetic susceptibility to osteoporosis

Family and twin studies have established a genetic contribution to the etiology of osteoporosis. The genes and allelic variants conferring osteoporotic risk are largely undefined, but the number of candidates has increased steadily in recent years (Table I). Osteoporosis is a complex disease, and allelic variation in many other candidate-genes including those that encode growth factors, cytokines, calciotropic hormones, and bone matrix proteins are likely to also play a role and warrant systematic investigation. Most family and association studies to date have focused on the genetic contributions to bone density, a major determinant of bone strength and fracture risk. Bone density is not the only determinant of skeletal fragility, however, and genetic influences on fracture risk are independent of bone density [Cummings et al., 1995]. The microarchitectural properties and overall size and geometry of bone also influence skeletal strength [Bouxsein et al., 1996], and the genetic influences on these phenotypes should be investigated more rigorously. Even fewer studies have assessed the association between candidate-gene variation and the risk of fracture, the most important clinical outcome of osteoporosis. Large-scale molecular epidemiologic studies will be increasingly necessary in the future to quantify the relative, absolute and attributable risks of fracture associated with specific genetic variants. Osteoporosis is a complex, multifactorial disease, and most candidate-gene association studies have had limited statistical power to assess gene-gene and gene-environment interaction. Although gender plays an important role in the development of osteoporosis, genetic studies have almost exclusively focused on women, and have not tested whether gender modifies the association between genetic variation and osteoporotic risk. Therefore, future genetic studies will need to recruit larger samples of individuals including men. Rapid additional progress in our understanding of the molecular basis of osteoporosis can be expected in the near future as ongoing genome-wide linkage [Spotila et al., 1996] and candidate-gene association analyses are completed. Linkage analyses in families at high-risk for rare metabolic bone diseases should also yield important clues to the pathogenesis of osteoporosis. Recent examples are the mapping of loci for both high [Johnson et al., 1997] and low [Gong et al., 1996] bone mass to chromosome 11q and osteopetrosis to chromosome 1p [Van Hul et al., 1997]. Similar ongoing studies in baboons [Rogers and Hixson, 1997] and mice [Beamer et al., 1997] may reveal additional loci whose human homologs contribute to osteoporotic risk. The improved understanding of osteoporosis that will emerge from these genetic studies should lead to better diagnosis of this disease and new treatment and prevention strategies.

Longitudinal changes in bone in men with spinal cord injury

INTRODUCTION

Quantitative bone assessment today is primarily based on the analysis of bone mineral density (BMD). The geometric and structural properties of bone, which are important parameters for skeletal strength, are generally not considered in the routine clinical assessment of spinal cord injury-related osteopenia.

OBJECTIVE

To study changes in structural and geometric properties of tibia bone longitudinally by means of peripheral quantitative computerized tomography and a biomechanical test method (bone stiffness measurement device Swing) in 12 subjects with spinal cord injury.

DESIGN

Measurements were conducted in the 5th week and around the 104th week after the spinal cord injury in a university hospital.

RESULTS

Paired Student's t-tests showed a significant decrease in trabecular (p < 0.05) and cortical bone (p < 0.05), as well as a significant decrease in geometric properties of tibia bone (p < 0.05) within two years after the spinal cord injury. Phase velocity propagation changed in three subjects within two years following the spinal cord injury.

CONCLUSIONS

This study indicates that beside changes in tissue composition, changes in bone geometric indices and in structural properties occur in the lower extremity after a spinal cord injury. In the tibia, consideration of geometric and biomechanical parameters of bone combined with bone mineral density measurements could result in an improved screening for spinal cord injury-related osteopenia and the prediction of fracture risk in spinal cord injury.

Characterization of bone quality using computer-extracted radiographic features

Both bone mineral density (BMD) and trabecular structure are important determinates of bone mechanical properties. However, neither BMD or trabecular structural features can completely explain the variations in bone mechanical properties. In this study, we combine BMD and bone structural features to characterize bone mechanical behavior. Radiographs were obtained from 34 femoral neck specimens excised during total hip arthroplasties. Each neck radiograph was digitized and a region of interest (ROI) was selected from the medial side of the femoral neck. Textural features, the global Minkoswski dimension and trabecular orientation, were extracted from each ROI image using Minkowski dimension analysis. The BMD of each specimen was measured using dual-energy x-ray absorptiometry (DXA) and subsequently normalized by bone size as measured from a standard pelvis radiograph. Mechanical testing was performed on the trabecular bone cubes machined from each femoral neck to yield bone mechanical properties. Multiple regression was performed to select the best features to predict bone mechanical properties. The results suggest that, using multiple predictors including normalized BMD structural features, and patient age, the coefficients of determination (R2) improved over the use of BMD alone. For bone strength, the R2 was improved from 0.24 using conventional BMD to 0.48 using a four-predictor model. Similar results were obtained in the prediction of Young's modulus, i.e., the R2 was improved from 0.25 to 0.55 in going from the model using conventional BMD to a four-predictor model. This study demonstrates the contributions of normalized BMD, structural features, and age to bone mechanical properties, and suggests a potential method for the noninvasive evaluation of bone mechanical properties.

Changes of tibia bone properties after spinal cord injury: effects of early intervention

OBJECTIVE

To evaluate the effectiveness of an early intervention program for attenuating bone mineral density loss after acute spinal cord injury (SCI) and to estimate the usefulness of a multimodality approach in diagnosing osteoporosis in SCI.

DESIGN

A single-case, experimental, multiple-baseline design.

SETTING

An SCI center in a university hospital.

METHODS

Early loading intervention with weight-bearing by standing and treadmill walking.

PATIENTS

Nineteen patients with acute SCI.

OUTCOME MEASURES

(1) Bone density by peripheral computed tomography and (2) flexural wave propagation velocity with a biomechanical testing method.

RESULTS

Analysis of the bone density data revealed a marked decrease of trabecular bone in the nonintervention subjects, whereas early mobilized subjects showed no or insignificant loss of trabecular bone. A significant change was observed in 3 of 10 subjects for maximal and minimal area moment of inertia. Measurements in 19 subjects 5 weeks postinjury revealed a significant correlation between the calculated bending stiffness of the tibia and the maximal and minimal area moment of inertia, respectively.

CONCLUSION

A controlled, single-case, experimental design can contribute to an efficient tracing of the natural history of bone mineral density and can provide relevant information concerning the efficacy of early loading intervention in SCI. The combination of bone density and structural analysis could, in the long term, provide improved fracture risk prediction in patients with SCI and a refined understanding of the bone remodeling processes during initial immobilization after injury.

Simultaneous densitometry and quantitative bone sonography in the estimation of osteoporotic fracture risk

759 post-menopausal women (41-80 years old), 175 with and 584 without vertebral fracture, were studied by quantitative bone sonography and densitometry of the distal radius in order to evaluate the ability of ultrasound transmission velocity (UTV) to separate fractured from healthy women independently of bone mineral density (BMD) and to test the possibility of improving the discriminant ability of BMD by the simultaneous use of UTV. A second BMD measurement was made at the mid radial shaft. Both BMD and UTV were higher in healthy subjects than in fractured women; the latter being older, shorter and having a longer postmenopausal status. On logistic regression, standardized for 1 SD from the mean value of healthy women, UTV differentiated between healthy and fractured subjects after correction for BMD. UTV was also a significant predictor of fracture in a selected subgroup of healthy and fractured women paired for BMD (144 pairs). In this same subgroup, the difference in UTV between fractured and healthy women regression lines was related to elasticity (E) variation between pairs. Simultaneously evaluating BMD and UTV as fracture predictors, logistic regression showed an odds ratio that was twice that of each predictor alone and 1.2 times higher than that derived from the simultaneous evaluation of two different BMD predictors. These data confirmed that UTV differentiates between healthy and fractured women both as well as and independent of BMD. In addition, UTV separated fractured from healthy BMD matched women by measuring non mass related differences. The simultaneous use of BMD and UTV improved the discriminant ability of each of them alone and of two simultaneous measurements of BMD detected at different skeletal sites.

Calcaneus as a site for the assessment of bone mass

The calcaneus is a skeletal site frequently used for monitoring bone loss after spaceflight, because it is sensitive to microgravity-induced bone mineral loss and reflects the degree of demineralization in the vertebra and the femoral neck. In this article, methods for assessing the calcaneus are reviewed, and their potential applications and limitations as the monitoring site for bone loss in weightlessness are discussed. Currently, single or dual energy X-ray absorptiometry appears to be most sensitive for monitoring bone mineral loss in weightlessness. The results of recent studies suggest two- to threefold longer follow-up times required for ultrasound techniques. However, ultrasound devices can be designed to be portable, making them attractive for inflight use, and ultrasound techniques are expected to provide information related to bone quality. Additional investigations that assess new ultrasound techniques would be important to determine and utilize the full potential of this technology for monitoring bone loss in weightlessness.

Utility of ultrasound to assess risk of fracture

Traditional assessments of bone properties have utilized densitometry techniques such as Dual Energy X-ray Absorptiometry (DXA). Recently, quantitative ultrasound (QUS) has been introduced as an alternative method of assessing bone properties. Advantages of QUS over X-ray techniques include low costs, portability, and nonionizing radiation. Proponents of QUS have claimed that this technology can provide information not only about the density but also about the structure and mechanical properties of bone. There are two major questions that need to be answered for those who seek to diagnose bone disorders with ultrasound: (1) what does quantitative ultrasound actually measure, and, even more importantly, (2) what is its clinical utility? In this review we will briefly examine the first question and will focus on the utility of ultrasound in clinical trials to discriminate between fractures and non-fractures and to predict the risk of fractures.

Ultrasound bone velocity on proximal phalanges in premenopausal, perimenopausal, and postmenopausal healthy women

RATIONALE AND OBJECTIVES

The authors studied premenopausal, perimenopausal, and postmenopausal women to determine if ultrasound bone velocity (UBV) on proximal phalanges of women reflect bone changes related to gonadal status and age.

METHODS

A total of 166 healthy women-64 postmenopausal women (mean age 58.7 +/- 9.4 years), 41 perimenopausal women (mean age 49.5 +/- 2.9 years), and 61 premenopausal women (mean age 36.8 +/- 7.1 years)-were studied. All the women underwent UBV study of the 2nd to 5th proximal phalanges on the nondominant hand and the mean value of all ultrasound measurements was calculated.

RESULTS

The postmenopausal women had a UBV that differed significantly, one-way analysis of variance, from that of the perimenopausal women and premenopausal women (both P < 0.001). The UBV measurements of the perimenopausal women differed significantly from those of the premenopausal women (P < 0.01). Simple linear regression analysis of the relation between UBV and age showed that this was significant and negative in the overall group of women (r = -0.69; P < 0.0001), significant in the perimenopausal (r = -0.66; P < 0.001) and postmenopausal women (r = -0.69; P < 0.001) and nonsignificant in the premenopausal women (r = 0.08; P not significant). In the postmenopausal women, the correlation between UBV and years since menopause was larger (r = -0.71; P < 0.0001) than the correlation between UBV and chronological age.

CONCLUSIONS

Ultrasound bone velocity of the phalanx, as a method for measuring changes in bone with age, has a precision that makes it possible to detect changes in bone mass in perimenopausal women and may perform similarly to other bone mass measurements.

The role of ultrasound in the assessment of osteoporosis: a review

Osteoporosis is now being recognized as a "silent epidemic" and there is an increasing need to improve its diagnosis and management. Quantitative ultrasound (QUS) measurement [broadband ultrasound attenuation (BUA) and velocity] is emerging as an alternative to photon absorptiometry techniques in the assessment of osteoporosis. The fundamental principles governing ultrasound measurements are discussed, and some of the commercially available clinical systems are reviewed, particularly in relation to data acquisition methods. A review of the published in vivo and in vitro data is presented. The general consensus is that ultrasound seems to provide structural information in addition to density. The diagnostic sensitivity of ultrasound measurement of the calcaneus in the prediction of hip fracture has been shown by recent large prospective studies to be similar to hip bone mineral density (BMD) measured with dual-energy X-ray absorptiometry (DXA) and superior to spine BMD. Ultrasound has also been shown to correlate better with the type of hip fracture (intertrochanteric or cervical) than BMD and to provide comparable diagnostic sensitivity to spine BMD in vertebral fractures. It has also been observed that combining the results of both ultrasound and DXA BMD significantly improved hip fracture prediction. Areas where further research is required are identified.

The epidemiology of quantitative ultrasound: a review of the relationships with bone mass, osteoporosis and fracture risk

Quantitative ultrasound (QUS) is a simple, inexpensive and non-invasive measure of bone which has been used in research settings for the prediction of osteoporosis. This review summarizes the current status of the epidemiology of QUS analysis, including its relationship with bone mineral density (BMD), risk of osteoporotic fracture and risk factors for osteoporosis. Although only moderately correlated with BMD, QUS appears to be as strong a predictor of osteoporotic fracture as BMD and may predict fracture independent of BMD. Risk factors for low QUS, including age, menopause, body composition and physical inactivity, seem to parallel those of low BMD. More longitudinal research is needed to confirm the clinical utility of QUS and more experimental and population-based studies are needed to determine whether the etiology of low QUS values is different from that of low bone mass.

Quantitative CT in the measurement of bone quantity and bone quality for assessing osteoporosis

The biomechanical strength of the skeleton, and hence the risk of future fractures, depends on both the bone quantity (assessed in terms of bone mineral density) and bone quality (assessed in terms of the integrity of its internal architecture). Precise methods of measuring the calcium-equivalent density of both the trabecular and cortical components of vertebral bone using quantitative computed tomography are presented. For a group of post-menopausal Kuwaiti females, we have shown that the trabecular and cortical components are highly correlated with each other at both the L3 and L4 lumbar vertebral levels, with correlation coefficients of 0.78 and 0.74 (P < 0.0001) respectively. We have explored the anisotropic distribution of trabecular bone and considered the use of the standard deviation and the coefficient of variation of trabecular CT numbers as texture indicators and surrogate measures of bone quality. The coefficient of variation was the better texture indicator: used with bone mineral density values it successfully discriminated between two classes of patients (those with fractures and those without) with high sensitivity (> or = 89%) and specificity (> or = 82%).

Correlation of ultrasound velocity in the tibial cortex, calcaneal ultrasonography, and bone mineral densitometry of the spine and femur

We compared the attributes of tibial cortex speed of sound (SOS) measurements with the SOS and broadband ultrasound attenuation (BUA) of the calcaneus, and bone mineral densities of the lumbar spine and femoral neck in a patient crossover study. The three instruments used in the crossover study were the LUNAR DPX and AchillesTM, and a newly introduced device for measuring tibial cortical SOS, the SoundScanTM 2000. Ultrasound precision determinations on the two instruments were performed with the same group of 10 volunteers, and the bone densitometry precision was derived from 22 patients who were assessed twice in a single visit, with repositioning between spine and hip scans. There were 220 female patients in the clinical study, 28 of whom had thoracic spine fractures, and all had measurements with the three instruments. Of the three instruments, the best precision, or lowest coefficient of variation and standardized coefficient of variation, was obtained with the SoundScanTM 2000; 0.20% and 1.39%, respectively. The tibial SOS correlated more poorly with the lumbar spine and femoral neck bone mineral densities (BMDs) than the calcaneal parameters in 220 patients. Tibial SOS measurements could not distinguish the group with spinal fracture from an age-matched control group to a P < 0.05 level, whereas the lumbar spine BMD and calcaneal BUA and stiffness showed a significant difference. We conclude that the SoundScanTM 2000 system measures propagation of sound in the tibial cortex with great precision, but its role in clinical practice is moot. Yet to be established by a long-term prospective study is its efficacy in predicting fracture risk and how well it reflects bone change in response to treatment of osteoporosis.

Broadband ultrasound attenuation of the os calcis in female postmenopausal patients with cervical and trochanteric fracture

The broadband ultrasound attenuation (BUA) of the right calcaneus was measured in 78 women with hip fracture (45 trochanteric and 33 cervical) and in 85 normal women (mean age 78 years and 63 years, respectively). All cases were postmenopausal and the hip fractures had resulted from a fall from standing position or less. The women with hip fracture had lower BUA (41 dB/MHz) than normals (67 dB/MHz), but about 10 dB/MHz of this difference was associated with age. There was no significant difference in BUA between cases with trochanteric (41 dB/MHz) and those with cervical fracture (39 dB/MHz). It is worth noting that 35.5% of the women with trochanteric fracture were suffering from osteoarthrosis of the knees but only 15% of the women with cervical fractures had the same problem. Over 90% of the cases with hip fracture had BUA lower than 61 dB/MHz and 80% had lower than 51 dB/MHz.

Ultrasound, densitometry, and extraskeletal appendicular fracture risk factors: a cross-sectional report on the Saunders County Bone Quality Study

The Saunders Bone Quality Study was designed to determine the feasibility of ultrasonic bone measurement, at the patella, as a predictor of low-trauma fractures in a rural population-based study. At the first visit of this 4-year longitudinal study, anthropometric and clinical measurements and medical, surgical and fracture histories were obtained for the 1428 participants 9899 women and 529 men). Explored risk factors for low-trauma fractures included age, sex, calcium intake, alcohol and caffeine ingestion, tobacco use, body mass and grip strength, age of menopause, estrogen replacement therapy, propensity to fall, distal radius and ulna bone mineral content, and bone density. Forward multivariate logistic regression analysis showed that lower ultrasound values are more consistently associated with reported low-trauma appendicular fractures than the commonly reported forearm absorptiometry measures of radius mineral content and density. When ultrasound, age, and the extra skeletal risk factors were included in an additional multivariate model, only age and ultrasound were significantly associated with appendicular fracture history in women (P = 0.0003), whereas only ultrasound was associated in the men (P = 0.001). We conclude that ultrasound is a better measure as association with reported low-trauma fractures than the commonly reported forearm SPA measures. Even after adjustment for many of the extra skeletal risk factors, low AVU is highly associated with low-trauma fracture status for both men and women.

Quantitative ultrasound bone measurements: normal values and comparison with bone mineral density by dual X-ray absorptiometry

Normative data for qualitative ultrasound (QUS) measurements: speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness were established in 118 healthy women aged 20-86 years and in 42 healthy men aged 22-76 years. The relations between age, weight, height, and QUS were studied. QUS measurements were negatively correlated with age in both sexes. In women, age was accepted as first factor (R2 = 0.39 for SOS, 0.35 for BUA, and 0.45 for stiffness, P < 0.001); weight was accepted as second factor for BUA (R2 = 0.44, P < 0.001). In men, age was the only significant parameter (R2 = 0.41 for SOS, 0.39 for BUA, 0.43 for stiffness, P < 0.001). QUS measurements of the right and left feet were highly correlated unless unilateral foot pathology such as algodystrophy was present. Significant correlations were found between QUS of the calcaneus and dual X-ray absorptiometry (DXA) of the lumbar spine (R = 0.67, P < 0.01 for SOS; R = 0.57, P < 0.02 for BUA; R = 0.65, P < 0.01 for stiffness).

A correlative study of ultrasound calcaneal and dual-energy X-ray absorptiometry bone measurements of the lumbar spine and femur in 1000 women

The objectives of the study were firstly to determine the accuracy of ultrasound calcaneal measurements in the prediction of bone mineral density determinations with dual-energy X-ray absorptiometry (DXA) of the lumbar spine (LS), femoral neck (FN), and Ward's triangle (FW) in a mixed population of 1000 women, unsorted as to diagnosis, and secondly to determine the accuracy of the various site-specific measurements in predicting each other. Ultrasound measurements [stiffness, speed of sound (SOS) and broadband ultrasound attenuation (BUA)] were made with the Lunar Achilles device, and the bone mineral density (BMD) of the LS, FN and FW were determined with the Lunar DPX. The data were analyzed for correlation, sensitivity, specificity, and accuracy of various paired sites. The coefficients of correlation of the young adult t-scores in the total group between calcaneal stiffness and BMDs of the LS, FN, and FW varied between 0.53 and 0.60. Coefficients for LS versus FN and FW were 0.70 and 0.62, respectively. A comparison of SOS and BUA values obtained at the calcaneus with BMDs of the LS, FN and FW yielded correlation coefficients that varied from 0.54 to 0.56. The general accuracy of prediction of one site by another ranged from 64.2% to 74.4%, where normality was defined as a t-score > -2. It is concluded that no site can predict the status of another site with sufficiently high accuracy to be clinically useful. The role of ultrasound transmission in bone as a predictor of fracture risk is theoretically promising, but has yet to be proved by a long term prospective study.

Ultrasound velocity, through bone predicts incident vertebral deformity

We followed 130 postmenopausal women without evidence of vertebral deformity by lateral spine radiographs on entry into study for 2 years, and repeat spine radiographs were taken at the end of that time. Incident deformities occurring within this 2 year period were detected by two methods, a level-specific radiogrammetric approach and visual inspection by skilled clinicians. Fourteen incident deformities were detected by the radiogrammetric method, and 19 by the clinicians. Ultrasound transmission velocity was measured at the patella in each subject on entry. Values for ultrasound velocity were significantly correlated with incident fracture occurrence, with individuals having velocity values more than one standard deviation below the mean for the group exhibiting from 3.3 to 4.6 times the probability of incident fracture as individuals with velocity values more than one standard deviation above the mean. Thus, low values for ultrasound transmission velocity at the patella detect yet-unexpressed bony fragility at the spine and predict future fracture.

Comparison of speed of sound ultrasound with single photon absorptiometry for determining fracture odds ratios

The purpose of this study was to compare the ability of ultrasound velocity measurement with that of single photon absorptiometry to determine the odds of history of fracture since age 40, for a population-based study. To do this we computed odds ratios and 95% confidence intervals for 809 women and 502 men, aged 50 years and older, who are participants in the prospective phase of the Saunders County Bone Quality Study. These participants received both the ultrasound and single photon absorptiometry bone measurements at the initiation of the study. In addition, a history of all fractures that had occurred to participants since age 40 was obtained. The two bone assessment methods were compared by examining the magnitude of the odds ratios, to determine which produces the highest estimate of the probability of odds of fracture, and by examining widths of the respective confidence intervals to show which estimate of odds ratio is the most precise. Ultrasound velocity estimates a higher probability of odds of both low-trauma fractures and all fractures than distal radius and ulna bone mineral content, but lower than bone mineral density at the same sites for both women and men. However, the ultrasound measure is more precise than bone mineral density, but less precise than bone mineral content. We conclude that ultrasound velocity is as good as single photon absorptiometry in estimating odds of fracture.

Osteoporosis and the jaws: questions remain to be answered

Osteoporosis is a major health issue in later life, which translates the age-associated increased risk of falls into a hip, shoulder or wrist fracture. The same pathology may result in vertebral crush fracture after minor loading of the axial skeleton. The health burden is enormous. Over a five year period, 10% of the female population of the United Kingdom, over 70 years of age, will suffer a fractured femoral neck, from which up to 20% may die and only a third of the survivors will be fully mobile at six months.