Influence of Physical Activity on Ultrasound and Dual-Energy X-ray Absorptiometry Bone Measurements in Peripubertal Girls: A Cross-Sectional Study

The aim of this cross-sectional study was to investigate whether two types of physical exercise affect the growing skeleton differently. We used calcaneal quantitative ultrasound measurements (QUS) and dual-energy X-ray absorptiometry (DXA) for measurement of bone mineral density (BMD), and to test how QUS values reflect the axial DXA values in these various study groups. A total of 184 peripubertal Caucasian girls aged 11–17 years (65 gymnasts, 63 runners, and 56 nonathletic controls) were studied. Weight, height, stage of puberty, years of training, and the amount of leisure-time physical activity were recorded. Broadband ultrasound attenuation (BUA) and sound of speed (SOS) through the calcaneus were measured. The BMD of the femoral neck and the lumbar spine were measured by DXA. The differences in mean values of bone measurements among each exercise group were more evident in pubertal than prepubertal girls. The mean BUA and SOS values of the pubertal gymnasts were 13.7% (77.8 dB/MHz versus 68.4 dB/MHz, P < 0.05) and 2.2% (1607.7 m/s versus 1572.4 m/s, P < 0.001) higher than of the controls, respectively. The mean BMD of the femoral neck in the pubertal gymnasts and runners was 20% (0.989 g/cm² versus 0.824 g/cm², P < 0.001) and 9.0% (0.901 g/cm² versus 0.824 g/cm², P < 0.05) higher than in the controls, respectively. The amount of physical activity correlated weakly but statistically significantly with all measured BMD and ultrasonographic values in the pubertal group (r = 0.19–0.35). The correlation between ultrasonographic parameters and BMD were weak, but significant among pubertal runners (r = 0.47–0.55) and controls (r = 0.39–0.42), whereas the DXA values of the femoral neck and the ultrasonographic parameters of the calcaneus did not correlate among highly physically active gymnasts. By stepwise regression analysis, physical activity accounted for much more of the variation in the DXA values than the ultrasonographic values. We conclude that the beneficial influence of exercise on bone status as measured by ultrasound and DXA was evident in these peripubertal girls. In highly active gymnasts the increase of the calcaneal ultrasonographic values did not reflect statistically significantly the BMD values of the femoral neck. Received: 28 June 1999 / Accepted: 2 November 1999     

Effect of Region of Interest Location on Ultrasound Measurements of the Calcaneus

Ultrasound (US) measurements of the calcaneus are usually carried out in a region of interest (ROI) at a fixed site relative to a footplate. Recently, US transmission systems have been developed with imaging capability that enable selection of the position of ROI; the region of measurement is always the area of minimum attenuation in the posterior part of the calcaneus. This study compares measurements of broadband ultrasound attenuation (BUA) and speed of sound (SOS) at the variable ROI of minimum attenuation (ROI_v) and at fixed coordinates (ROI_f). Ultrasound variables were estimated at ROI_v and ROI_f in 212 female subjects, including 26 patients with osteoporotic fractures. Among the 186 women without fractures, 63 were classified as having osteoporosis on the basis of their vertebral bone density. Precision of BUA and SOS were better at ROI_v than at ROI_f. BUA was more highly correlated with bone mineral density (BMD) at the lumbar spine and femoral neck at ROI_v than ROI_f (r = 0.64 for lumbar spine and 0.68 for femoral neck at ROI_v versus 0.50 for lumbar spine and 0.54 for femoral neck at ROI_f, P < 0.05 for both comparisons). There were no significant differences between the correlations of SOS with axial BMD at ROI_v compared with ROI_f. Significant difference was found between the areas under the ROC curve for each ultrasound variable at ROI_v and ROI_f for both groups of patients, subjects with osteoporosis (area under curve = 0.87 for BUA at ROI_v versus 0.82 at ROI_f, P < 0.05; area under curve = 0.85 for SOS at ROI_v versus 0.81 at ROI_f, P < 0.05), and women with fractures (area under curve = 0.93 for BUA at ROI_v versus 0.86 at ROI_f, P < 0.05; area under curve = 0.91 for SOS at ROI_v versus 0.82 at ROI_f, P < 0.05). Ultrasound variables measured at ROI_v enable improved reproducibility and significantly better differentiation of diseased subjects from healthy individuals as compared with measurements at ROI_f. Received: 3 November 1997 / Accepted: 20 February 1998     

Ultrasound velocity and broadband attenuation as predictors of load-bearing capacities of human calcanei

The main purpose of this study was to determine whether calcaneal ultrasound parameters, measured in the mediolateral direction, reflect load-bearing capacities of human calcanei. Broadband ultrasound attenuation (BUA) and ultrasound velocity (UV) were measured in 20 cadaveric calcanei with a mean age of 74.1 (SD 8.8). Normalized BUA (nBUA) was determined by dividing BUA by the calcaneal thickness obtained using a pulse-echo technique. The bone mineral density (BMD) of each calcaneus was measured by quantitative computed tomography. The calcanei were embedded in PMMA to simulate the midstance physiologic orientation during compressive testing in the load-bearing direction. The failure load, stiffness, and energy absorption were determined for each calcaneus. It was shown that BMD was well correlated with all ultrasound parameters (P < 0.0001). BMD, BUA, nBUA, and UV were all significantly associated with calcaneal failure load, stiffness, and energy absorption capacity (P < 0.05). nBUA was found to be the strongest predictor of all compressive properties. BUA and BMD demonstrated similar predictability of stiffness and energy absorption capacity, however, BUA showed a more significant relationship to the failure load of the calcaneus than did BMD. UV was found to be inferior to BMD, as well as BUA or nBUA, in assessing failure load, stiffness, and energy absorption capacity. It was also shown that nBUA was superior to BUA in the assessment of load-bearing capacity, but not in the prediction of BMD. Multivariate regression analysis showed that the combination of BUA or nBUA with UV did not improve the predictability of failure load, stiffness, and energy absorption capacity over that of BUA or nBUA alone (P > 0.5). Received: 29 December 1995 / Accepted: 3 May 1996     

Ultrasound Bone Densitometry of the Os Calcis in Children and Adolescents

The aim of the present investigation was to evaluate reference data and to examine whether there were weight-, height-, age-, and sex-related differences of the quantitative ultrasound bone parameters for healthy children and adolescents. A total of 3299 healthy Caucasian children and teenagers (1623 girls and 1676 boys), age range from 6–18 years (mean age 11.4 ± 3.4 years for boys and mean age 11.5 ± 3.3 years for girls) were examined by quantitative ultrasound densitometry (QUS) using the bone sonometer SAHARA (Hologic Inc., Waltham, MA, USA), a waterless, dry system. The parameters broadband ultrasound attenuation (BUA) [dB/MHz] and speed of sound (SOS) [m/second] were evaluated on the right heel in relation to age, sex, weight, and height. There is no correlation between the ultrasound bone parameter SOS and age, height, and weight. BUA increases with age, height, and weight. Significant differences in SOS and BUA between girls and boys were found to probably be caused by the different onset of growth phases and the onset of puberty. SOS and BUA are influenced by changes of bone mineral density. But BUA is dependent on bone size, too. In conclusion, ultrasound bone densitometry is a useful measuring method showing the physiological bone development in childhood and adolescence. The presented results can be used as reference data. Further studies in children with disorders influencing bone metabolism will show in what way various patterns of osteopenia in childhood can be detected. Received: 20 August 1999 / Accepted: 20 April 2000 / Online publication: 22 September 2000     

Ultrasound Transmission Through the Os Calcis in Children: Which Side Should We Measure?

Ultrasound measurement of the os calcis is a promising technique when evaluating bone status. Large individual differences between the right and left calcaneus in adults were reported. In this study, calcaneal acoustic parameters in 373 healthy children and adolescents were investigated using a CUBAClinical bone densitometer. No significant difference was found between mean values on the right and left foot, however, individual difference in broadband ultrasound attenuation was 11 ± 9.25%. Individual differences between both sides in ultrasound investigation of the os calcis should not be underscored either in adults or in children. Received: 2 July 1996 / Accepted: 3 January 1997     

Usefulness of Ultrasound in Sudeck's Atrophy of the Foot

Quantitative ultrasound (QUS) of bone has been proposed as an inexpensive and radiation-free device method of assessing skeletal status. QUS has been widely used in the assessment of osteoporosis. Until now only few data are available on the usefulness of QUS in different disorders, such as Sudeck's atrophy. To evaluate the ability of QUS in the diagnosis and monitoring of regional osteoporosis, we investigated 19 patients (12 women and 7 men, age range 30–65 years) with osteoporosis of the foot (Sudeck's atrophy), as evidenced by X-ray study and Technetium-99 bone scan. In all patients we measured speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness of the calcaneus using Lunar Achilles Ultrasound, both in the affected and unaffected foot. Bone mineral density at the lumbar spine, by DXA (Hologic QDR 1000), was also performed. QUS was repeated after 3 and 6 months of treatment with salmon calcitonin (100 IU I.M. every second day). At baseline, SOS, BUA, and stiffness, expressed as T-score, were −1.9, −2.4, and −2.4 in unaffected feet and −2.9, −5.1, and −4.3, respectively, in affected feet. The difference between the unaffected and affected foot was significant for SOS, BUA, and stiffness (P < 0.001). No significant difference was found in QUS parameters in the unaffected foot during the study period. After 3 and 6 months of treatment, SOS increased in the affected foot by 0.2% and 0.3%, BUA increased by 6.2% and 8.2%, and stiffness by 7.5% and 11.1%, respectively. In conclusion, BUA and stiffness seem to be influenced more than SOS by Sudeck's atrophy; QUS, namely, BUA and stiffness, significantly increase with calcitonin treatment. In conclusion, QUS is a sensitive tool in the diagnosis of Sudeck's atrophy of the foot and is adequate for measuring improvement in bone status following treatment. Received: 7 June 1997 / Accepted: 15 October 1997     

Influence of Grip Strength on Metacarpal Bone Mineral Density in Postmenopausal Japanese Women: A Cross-Sectional Study

Most published studies on the role of muscle strength in the maintenance of bone mineral density (BMD) focused on the relationship between specific muscle groups and adjacent bones, mostly in young and premenopausal women. This study examined the influence of grip strength on BMD of the metacarpal index in postmenopausal Japanese women. Subjects included 1168 postmenopausal women aged 40–70 years. BMD measurement was done with computed X-ray densitometry (CXD) by analyzing X-ray films of the right second metacarpal index. Grip strength was measured in both the dominant and nondominant hands using a squeeze dynamometer. Grip strength (r = 0.2474; P= 0.0001) and age (r =−0.5443; P= 0.0001) significantly correlated positively and negatively, respectively, with BMD. Physical activity (r = 0.1318; P= 0.0001) also correlated positively with BMD. Breastfeeding (r =−0.1658; P= 0.0001), however, correlated negatively with BMD. Subjects with a history of regular physical activity had higher grip strengths and BMD, than those with no physical activity. Adjustment for age, physical activity, calcium intake, BMI, breastfeeding, testing site, and menopausal type indicated a significant (P for trend = 0.0013) positive association of grip strength with BMD. Subjects with stronger grip strengths had a decreased risk for low BMD. Received: 24 February 1998 / Accepted: 7 August 1998     

Ultrasound Characterization of Bone Demineralization

Quantitative ultrasound (QUS) assessment of bone may permit an assessment of bone properties currently not available by bone densitometry techniques. To explore the effects of the quantity of bone mineral on acoustic parameters, we carried out an in vitro study of the impact of demineralization on attenuation of ultrasound in trabecular bone. Ten fresh cubes of trabecular bone obtained from bovine distal femurs were progressively demineralized using formic acid solution. The progression of demineralization was controlled by monitoring the specimen bone mineral density (BMD) using dual x-ray absorptiometry (DXA). At five stages of demineralization—0% (baseline), 25%, 50%, 75%, and 100% (all mineral removed)—the US properties of the specimens were assessed (Walker Sonix UBA 575+). The US parameters investigated were broadband ultrasound attenuation (BUA) and ultrasound attenuation in bone (UAB). Both DXA and QUS measurements were made along the three orthogonal axes of each cube. Our results demonstrated significant variability in both BUA and UAB along the three principle axes of the cubes whereas BMD did not differ in the different directions. A strong but nonlinear correlation was found between BMD and US attenuation. A reduction in BMD to 50% of the baseline values resulted in BUA (UAB) reduction to 25% and 19%, respectively. A random effect model analysis supported a multiplicative relationship between BMD and the US parameters. US attenuation is a sensitive indicator of bone mineral changes with nonlinear dependence on bone mineral loss. Bone collagen structure reinforced by hydroxyapatite crystal accounts for fundamental US characteristics. Ultrasound attenuation associated with trabecular orientation is basically dominated by the mineral spread in a collagen framework. Received: 3 February 1997 / Accepted: 2 July 1997     

Comparison of Quantitative Calcaneal Ultrasound and Dual Energy X-ray Absorptiometry in the Evaluation of Osteoporotic Risk in Children with Chronic Rheumatic Diseases

Osteoporosis is a common complication in children with chronic rheumatic diseases (CRD). Although dual energy X-ray absorptiometry (DXA) is increasingly being used to determine bone mineral density (BMD) in children, it exposes the subject to ionizing radiation and does not provide a measure of true bone density; in fact, in growing bones the increase in BMD is mainly caused by the increase in bone size. In recent years, quantitative ultrasound techniques (QUS) have been used in radiation-free assessment of bone density and ``bone quality' by measurement of the ultrasound waves attenuation by bone (BUA). In the present study we made a direct comparison of BUA in the calcaneum, determined by the pediatric contact ultrasound bone analyzer (CUBA) with lumbar BMD measured by DXA, in a group of 6–18-year-old patients with CRD. The study group consisted of 53 patients affected with juvenile rheumatoid arthritis (n = 29), systemic lupus erythematosus (n = 13), and juvenile dermatomyositis (n = 11). Mean age was 13.02 ± 2.69 years. In 22 patients (19 girls, 3 boys) both DXA and CUBA were repeated after 1 year in order to assess the mean percentage rate of BMD and BUA change over this time. Both lumbar spine BMD and calcaneal BUA measurements were lower in the CRD patients compared with a control group (P < 0.001). Calcaneal BUA was significantly correlated (r = 0.83, P < 0.001) with lumbar spine BMD. Age and sex correction (Z-score) did not change the relationship between BUA and BMD (r = 0.80, P < 0.001). A significant correlation between the mean percentage of variation (Δ%) of BMD and BUA (r = 0.76, P < 0.001) was also demonstrated in the 22 patients who were evaluated prospectively. Portability, ease of use, lower cost, and absence of radiation make CUBA a promising means of evaluating BMD in children. Received: 12 December 1998 / Accepted: 13 January 2000     

Osteogenesis Imperfecta: Bone Turnover, Bone Density, and Ultrasound Parameters

We studied 21 patients (11 men and 10 women) with osteogenesis imperfecta (OI) and 21 age- and sex-matched controls. In all patients we measured serum levels of total alkaline phosphatase (ALP), type I procollagen carboxy-terminal propeptide (PICP), osteocalcin (BGP), urinary excretion of hydroxyproline (HOP/Cr), and pyridinoline crosslinks (Pyr/Cr). Bone mineral density was measured at the distal radius (BMD-R) and at the lumbar spine (BMD-LS) by dual X-ray absorptiometry (DXA). Ultrasound parameters were also performed at the calcaneous with the Achilles device and at the phalanxes with DBM Sonic 1200. A significant reduction (P < 0.001) in BMD and in ultrasound parameters was found in OI patients compared with normals. PICP was significantly reduced in the OI patients compared with controls (P < 0.001); other markers of bone turnover were higher in OI than in controls, but the difference did not reach the statistical significance. A significant correlation (P < 0.05) was found between PICP and BMD at the lumbar spine and between PICP and ultrasound parameters at the calcaneous. On the basis of our data, we conclude that patients with OI show low values of BMD and ultrasound parameters; therefore in these patients, not only is bone mass disturbed but also bone quality. The reduced levels of PICP in OI patients confirm that most OI patients have defects in collagen I biosynthesis. These defects may contribute to the fragility of OI bone by interfering with complete mineralization and/or normal tissue structure. PICP may be considered a useful marker in the clinical management of OI. Received: 26 March 1998 / Accepted: 15 January 1999     

The Effects of 10 Weeks Military Training on Heel Ultrasound and Bone Turnover

To measure the physiological changes in bone in response to strenuous exercise we performed a prospective study of male army recruits over 10 weeks of basic training. Measurements performed at the start and completion of training consisted of ultrasound (US) measurements of the heel: velocity of sound (VOS in m/seconds) and broadband ultrasound attenuation (BUA in dB/MHz) and bone turnover markers; osteocalcin (OC), bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase (TRAP). Forty subjects were recruited for the study and 26 completed training. Over the 10-week study period there was a significant 1.7% fall in mean VOS [mean paired difference (mpd) 27.2 m/second, SEM 9.5 (95% CI 7.5–46.8) P= 0.009] and a nonsignificant 3.4% increase in BUA (P= 0.159). There were significant falls in markers of bone formation OC [11.6%, mpd 0.11 μg/liter (95% CI 0.07–0.14) P < 0.001] and BALP [13.3%, mpd 3.49 U/liter (CI 0.80–6.18) P= 0.013] and a nonsignificant 9.5% fall in TRAP a marker of bone resorption. The 10 recruits subsequently injured had a significantly lower VOS on entry [mean difference 24.2 m/seconds (95% CI 4.6–43.7) P= 0.017] and nonsignificantly raised BUA and baseline levels of all bone markers. The ultrasound changes may be accounted for by increase in trabecular separation and a fall in trabecular connectivity due to microfracture. The decrease in bone markers implies a fall in bone turnover. Received: 26 June 1997 / Accepted: 26 August 1998     

Bone Metabolism in Endurance Trained Athletes: A Comparison to Population-Based Controls Based on DXA, SXA, Quantitative Ultrasound, and Biochemical Markers

In general, physical exercise appears to have favorable effects on the skeleton. However, a few recent reports have described negative effects, including reduced bone density (BMD) and high bone turnover in runners. The aim of our study was to compare endurance runners to controls with respect to BMD at different sites and ultrasound transmission through the peripheral skeleton, and to use PTH, total serum calcium, and biochemical markers of bone metabolism as a complement in evaluating the effects of endurance running on bone. Thirty runners (mean age 32 years, range 19–54 years) participated in the study. Their main form of training consisted of endurance running at moderate intensity for about 7 hours (range 2–12 hours) per week, and they had been active in their sport for about 12 years (range 1–21 years). For a comparison, 30 age- and sex-matched population based controls were investigated. BMD values, measured by dual energy X-ray absorptiometry (DXA), were higher in runners than in controls for the total body (3.6%; P= 0.03), legs (9.6%; P= 0.001), femoral neck (10.0%; P= 0.01), trochanter (9.9%; P= 0.01), and Wards triangle (11.8%; P= 0.02), but not in the lumbar spine or in the forearm measured by single energy X-ray absorptiometry (SXA). The quantitative ultrasound measurement of the calcaneus also revealed higher values in runners than in controls for both broadband ultrasound attenuation (9.2%; P= 0.002) and speed of sound (3.1%; P= 0.0001). At all sites, BMD was related to ultrasound measurements in controls, but no such relationship was evident in runners. Concentrations of parathyroid hormone (PTH) were lower (23.2%; P= 0.02) in runners than in controls, whereas total serum calcium concentrations were slightly higher (3.0%; P= 0.003). The levels of PICP (bone formation) and ICTP (bone resorption) in serum were lower (18.0%; P= 0.03 and 22.2%; P= 0.004, respectively) in runners than in controls, but no differences were seen for osteocalcin or bone specific alkaline phosphatase (b-ALP). In conclusion, BMD at the focus of strain for running, that is, the legs, is higher in endurance runners when compared to matched controls. Low bone turnover in runners, indicated by lower levels of PTH and biochemical markers of bone metabolism, point to an influence of endurance running at the cellular level. Received: 25 July 1996 / Accepted: 24 March 1997     

Ultrasound and X-ray-Based Bone Densitometry in Patients with Anorexia Nervosa

In 20 patients (mean age 23 ± 5 years) with anorexia nervosa (AN), bone mass was evaluated by broadband ultrasound attenuation (BUA) of the calcaneus, peripheral quantitative computed tomography (pQCT) of the distal radius, and dual X-ray absorptiometry (DXA) of the lumbar spine and the hip. Compared with 20 age- and sex- matched healthy controls, patients with AN showed marked osteopenia at all measuring sites. Values of BUA (33.0 ± 9dB/MHz vs. 51.0 ± 5.7 dB/MHz; P < 0.0001) and of BMD of all regions of the hip (e.g., femoral neck: 0.71 ± 0.13 g/cm² versus 0.89 ± 0.07 g/cm²; P < 0.001), lumbar spine (0.82 ± 0.15 g/cm² versus 1.24 ± 0.06 g/cm²; P < 0.003) and total BMD of the peripheral radius (303.2 ± 75 g/cm³ versus 369.4 ± 53.2 g/cm³, P < 0.001) were significantly reduced. Calculating a Z-score we found the most prominent differences between AN and controls by BUA of the calcaneus (−3.2 ± 1.6), followed by DXA at the lumbar spine (−2.9 ± 2.2) and the hip (femoral neck −2.1 ± 1.7) and by pQCT at the distal radius (total BMD −1.2 ± 2.0). There were highly significant correlations between BUA of the calcaneus and BMD of the femoral neck (r = 0.78, P < 0.0001) and lumbar spine (r = 0.75, P < 0.0001) as well as between BMD values of the femoral neck and lumbar spine (r = 0.95; P < 0.0001). In addition, there were significant correlations (P < 0.001) between body mass index (BMI) and the three different measuring sites and between the duration of the disease and BUA (r = 0.5, P < 0.05). Our data suggest that BUA of the calcaneus is a valuable tool in the management of osteoporosis. Being a fast, radiation-free investigation method of good acceptance, it may be well suited for an assessment of the skeletal status in patients with AN. Received: 14 October 1998 / Accepted: 10 December 1999     

Differential Effects of Primary Hyperparathyroidism on Ultrasound Properties of Bone

Primary hyperparathyroidism (PHPT) may result in greater cortical than trabecular bone loss. Ultrasound is able to predict osteoporotic fracture risk independent of densitometric measurements, but little is known about the changes in ultrasound variables with PHPT. The aim of our study was to examine the effect of PHPT on ultrasound variables and bone density measurements at cortical (hand) and trabecular (lumbar spine and heel) sites, and to evaluate their reversibility following surgical treatment. We recruited 25 postmenopausal women diagnosed with PHPT ages 51–76 years (mean 62 years) and 95 postmenopausal controls ages 57–80 years (mean 67 years). Measurements were made at baseline and 1 year. Speed of sound (SOS) and broadband ultrasound attenuation (BUA) of the heel were measured using the Lunar Achilles (LA+) and McCue CUBA Clinical (CC). Amplitude-dependent speed of sound (AD-SoS) and ultrasound bone profile index (UBPI) of the fingers were measured using the IGEA DBM Sonic. Bone mineral density (BMD) of the hand and lumbar spine (LS) were measured by dual-energy X-ray absorptiometry (DXA). At baseline, hand BMD, LS BMD and heel BUA were significantly lower and finger UBPI significantly higher in the PHPT patients compared with controls (p<0.001). There were no differences in Stiffness Index, heel SOS or finger AD-SoS between control and PHPT subjects. At 1 year postoperatively, there was a mean (±SD) increase in LS and hand BMD of 3 ± 1% (p<0.01). BUA at the heel increased (11 ± 5%, p<0.001), and UBPI of the fingers decreased (17 ± 7%, p<0.001) probably reflecting different modes of attenuation in trabecular (scattering) and cortical (absorption) bone. Stiffness Index, SOS of the heel and AD-SoS of the fingers did not change. BUA, UBPI and BMD returned towards normal postmenopausal values following surgery. There were no changes in BMD or QUS variables at 1 year in the control group. Quantitative ultrasound (QUS) measurements provide different information about bone structure than densitometric measurements and cannot be regarded as simply reflecting bone density. With further research the combined use of BMD and QUS could improve the assessment of skeletal status in patients with PHPT before and after surgery. Received: 10 September 2001 / Accepted: 31 January 2002     

Acute and Subacute Changes in the Ultrasound Measurements of the Calcaneus Following Intense Exercise

The amount of exercise necessary to cause bone structural change in humans is unknown. We examined whether a single bout of intense exercise in vivo leads to acute and subacute changes in the physical properties of bone as measured by ultrasound. It was hypothesized that structural changes such as accumulation of fatigue microdamage would result in a decrease in velocity of sound (VOS) and broadband ultrasound attenuation (BUA) across the calcaneus. We performed a prospective cohort study in 111 (97 M, 14 F) entrants of the 1996 Melbourne marathon (42.3 km) and 28 (10 M, 18 F) nonrunning controls. Runners had a mean (SD) age of 45.3 ± 11.4 years (range 20–75), had completed 15.2 ± 17.3 prior marathons (0–88), and had been running regularly for 14.2 ± 9.2 years (0.25–50). An ultrasound densitometer (Cuba Clinical, McCue) was used to measure VOS and BUA across the right calcaneus. Runners were tested on three occasions: 1-3 days prior to, immediately after (<2 hours), and 5-6 days following the marathon. Seventy-three (66%) runners presented for all three measurements. Controls were tested on three occasions with the same time intervals as the runners. BUA values in the runners were significantly elevated by 5.0% immediately after the marathon but returned to baseline levels by the third test session (P= 0.0001). Changes in BUA values in the controls were not significant and all were less than 0.7% (P= 0.88). Age was a significant independent predictor of the BUA change between test 1 and test 2 in the runners (β= 0.2094; SE = 0.0917; P= 0.03). VOS measurements were not significantly different across the three testing sessions in both the runners (P= 0.07) and the controls (P= 0.33). Therefore, ultrasound measurements of BUA and VOS did not detect evidence of lasting structural change in the calcaneus following a marathon. Received: 15 July 1997 / Accepted: 11 May 1998     

Bone Response to In Vivo Mechanical Loading in Two Breeds of Mice

We investigated the bone response to external loading in C57BL/6J and C3H/HeJ mice, both breeds with low and high bone density, respectively. An in vivo tibial four-point bending device previously used for application of measured external loads in rats was adapted for mice. It delivered a uniform medio-lateral bending moment to the region of the tibia located 1–5.5 mm proximal to the tibio-fibula junction. The right legs of six C57BL/6J [low bone density (LBD)] and C3H/HeJ [high bone density (HBD)] mice were externally loaded in the device for 36 cycles/day at 2 Hz, 6 days/week for 2 weeks at 9.3 ± 0.9 N force, inducing estimated lateral periosteal surface compressive strains of 5121 ± 1128 με in C3H/HeJ (HBD) mice (n = 6), significantly higher than the estimated 3988 ± 820 με in C57BL/6J mice (n = 6) (mean ± SD). In addition, C3H/HeJ HBD mice (n = 11) were externally sham (pad pressure or no bending) loaded in the device for 36 cycles/day at 2 Hz, 3 days/week for 3 weeks at 9.3 ± 0.9 N force. Calcein injections for bone labeling were given at the 10th and 3rd days before sacrifice. At the end of the experiment, all mice were killed and both tibiae were removed, fixed, embedded, and cross-sectioned through the loaded region. Both tibiae were measured for marrow area (Ma.Ar), cortical area (Ct.Ar), total area (Tt.Ar), cross-sectional moment of inertia (CSMI), and periosteal and endocortical woven bone surface (Wo.B/BS), single-labeled surface (sLS), double-labeled surface (dLS), and total formation surface (FS/BS). Differences in all variables due to breed and loading (both bending and sham-bending) were tested by two-way analysis of variance (ANOVA) (P < 0.05). Ma.Ar, Tt.Ar, and CSMI were greater in C57BL/6J (LBD) than in C3H/HeJ (HBD) mice. Periosteal and endocortical woven bone and formation surface were increased significantly more by loading (bending) in C57BL/6J than in C3H/HeJ mice. Periosteal woven bone response due to sham-bending or sham-loading was significantly lower than due to bending loads in the C3H/HeJ mice. We conclude that the bone response to external loading is greater in LBD mice than in HBD mice. The high bone density of C3H/HeJ (HBD) mice is related to breed-specific factors other than the response to loading. Received: 5 March 1997 / Accepted: 8 April 1998     

Influence of Bone Quality on Precision of Calcaneal Ultrasonometry

This study was designed to determine the changes in precision of the ultrasound parameters speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI) as a function of bone quality. The instrument used in this investigation was the LUNAR Achilles. Of the 608 female patients who had paired measurements with repositioning, 200 had t scores ≥−1 and 408 had t scores ≤−2.5, thus rendering a normal and a grossly abnormal group for comparison of precision results. It was found that the median precision error (CV%) for BUA was 1.99% for normal bone and 1.44% for abnormal bone (P= 0.02). No significant difference was obtained between median precision errors in normal and abnormal bone for the parameters SOS and SI, which were 0.23% and 0.19%, and 2.15% and 2.02%, respectively. In the interquartile range, the mean precision errors for SOS and BUA were significantly different in normal and abnormal bone: SOS was 0.25% and 0.21%, respectively, and BUA was 2.31% and 1.85%, respectively. No significant change was registered for SI. Precision error appears to decrease slightly at lower values for calcaneal variables. Received: 21 August 1996 / Accepted: 5 March 1997     

Site-Specific Bone Measurements in Patients with Ankle Fracture

Ankle fracture is one of the most common fractures in adults, particularly postmenopausal women. Few studies have examined the bone mineral density (BMD) and ultrasound properties of bone close to the site of fracture in patients with ankle fracture. The aim of this study was to evaluate these measurements in women with ankle fractures compared with controls. We studied 31 healthy post-menopausal women ages 50–79 years (mean age 63.2 ± 3.3 years) from a population-based group and 31 postmenopausal women ages 52–76 years (mean age 61.2 ± 2.2 years) with an ankle fracture. Distal tibia and fibula BMD were measured by dual-energy X-ray absorptiometry using the Hologic QDR 1000/W densitometer. In addition to total distal and tibia BMD, three subregions were automatically selected: ultradistal, middle and one-quarter regions. Speed of sound (SOS) and broadband ultrasound attenuation (BUA) of the calcaneus were measured using the Lunar Achilles+ (LA+) and CUBA Clinical (CC). In addition to SOS and BUA, LA+ Stiffness Index (SI) was also measured. The nondominant limb was measured in the population group and the contralateral limb in the ankle group. Differences between the groups were determined using t-tests. The ankle fracture group was heavier than the control group by an average of 10 kg. BMD measurements were therefore adjusted for weight. There were no significant differences between the ankle fracture and control groups in lumbar spine BMD, total or regional ankle BMD or calcaneal BUA. However, calcaneal SOS was decreased in the ankle fracture group when measured on the LA+ and CC by 50 m/s (–2.0 SD units, p<0.001) and 19 m/s (–0.5 SD units, p<0.01) respectively. LA+ SI was decreased in the ankle fracture group by 14 units (–1.1 SD units, p<0.001). In conclusion, ankle fracture is not a typical osteoporotic fracture. However, there may be structural changes in the bone (unrelated to bone density) which result in increased fragility and susceptibility to fracture. Received: 7 May 2001 / Accepted: 29 August 2001     

Discordance Between Ultrasound of the Calcaneus and Bone Mineral Density in Black and White Women

Black women have 40% of the incidence rate for hip fracture and have a higher bone mineral density (BMD) than white women. The possibility was raised that bone quality may be disproportionately greater than the advantage in bone density in protection against osteoporotic fractures in black versus white women. Ultrasound (US) of the calcaneus is believed to measure properties of bone in addition to its density. We performed bone density measurements and US of the calcaneus in 108 black and 177 healthy white women, aged 20–70 years. The highest correlation was seen between total body bone density and speed of sound (r = 0.75). The interracial differences in BMD were all statistically significant and varied from 3.4 to 7.6%. The US measurements had lesser interracial differences than the bone density measurements, with velocity barely different between races. These findings suggest that US of the calcaneus measures properties of bone different from density. Fracture prediction data using US from prospective data in white women should not be extrapolated to black women because of the discordance between bone density and US measurements. Prospective studies are needed comparing US measurements in black women to the occurrence of osteoporotic fractures. Received: 30 May 1997 / Accepted: 8 January 1998     

Cross-Sectional Study of Weight-Bearing Activity on Proximal Femur Bone Mineral Density

In this cross-sectional study we investigated the effect of compressive and tensile forces applied on the proximal femur during weight-bearing activities. Ninety-seven men (29.9 ± 1.7 years) were divided into two groups: 69 exercisers who had practiced regular high-impact weight-bearing activities for at least 5 years and 28 controls who had been sedentary for at least 5 years. The maximum isometric hip abduction strength was measured. The bone mineral density (BMD) of the femoral neck and the greater trochanter was assessed using dual-energy X-ray absorptiometry (DXA). Controls were considered as the reference population to calculate the Z score. Mean BMD values of the femoral neck were 0.97 g/cm² on both sides in the exercisers and 0.83 g/cm² on the right side and 0.84 g/cm² on the left side in the controls. Mean BMD values of the greater trochanter were 0.86 g/cm² on the right side and 0.87 g/cm² on the left side in the exercisers, 0.73 g/cm² on the right side and 0.72 g/cm² on the left side in the controls. The BMD was significantly higher in exercisers at both trochanteric and cervical sites (P= 0.0001). Both left and right hip abduction strength was significantly greater in the exercisers than in the controls (P < 0.05) and was positively correlated to cervical and trochanteric BMD (P < 0.01). In the exerciser group, the trochanteric Z score was higher than the cervical Z score at both right (P= 0.06) and left (P= 0.002) sides. Therefore, the proximal femoral BMD was significantly greater in exercised subjects as compared with sedentary controls. The difference was observed at the level of both the femoral neck (where it is known anatomically that only compressive gravitational forces are exerted) and the greater trochanter (where it is known that tensile forces are exerted). This result suggests the participation of both compressive and tensile forces in the mechanisms by which exercise influences bone trophicity. Received: 19 November 1997 / Accepted: 7 August 1998