Influence of brisk walking on the broadband ultrasonic attenuation of the calcaneus in previously sedentary women aged 30-61 years

Quantitative Ultrasound and bone's response to exercise: a meta analysis

The utility of Quantitative Ultrasound (QUS) for assessing and monitoring changes in bone health due to exercise is limited for lack of adequate research evidence. Restrictions to bone density testing and the enduring debate over repeat dual energy absorptiometry testing spells uncertainty over clinical and non-clinical evaluation of exercise for prevention of osteoporosis. This study, via systematic review and meta-analysis, aimed to paint a portrait of current evidence regarding QUS' application to monitoring bone's adaptive response to exercise interventions.

METHODS

Structured and comprehensive search of databases was undertaken along with hand-searching of key journals and reference lists to locate relevant studies published up to December 2011. Twelve articles met predetermined inclusion criteria. The effect of exercise interventions for improving bone health, as measured by QUS of the calcaneum, was examined across the age spectrum. Study outcomes for analysis: absolute (dB/MHz) or relative change (%) in broadband ultrasound attenuation (BUA) and/or os calcis stiffness index were compared by calculating standardised mean difference (SMD) using fixed- and random-effects models.

RESULTS

Quality of included trials varied from low to high on a scale of one to three. Four to 36months of exercise led to a significant improvement in calcaneum BUA (0.98 SMD, 95% CI 0.80, 1.16, overall effect Z-value=10.72, p=0.001) across the age spectrum.

CONCLUSION

The meta-analysis attests to the sensitivity of QUS to exercise-induced changes in bone health across the age groups. QUS may be considered for use in exercise-based bone health interventions for preventing osteoporosis.

The association between physical activity in different domains of life and risk of osteoporotic fractures

A large body of epidemiological evidence suggests an inverse relationship between physical activity and risk of fractures. However, it is unclear how this association varies according to the domain of life in which the activity is undertaken. In this analysis of the European Prospective Investigation of Cancer-Norfolk study, we assessed total and domain-specific physical activity using a validated questionnaire (EPAQ2) in 14,903 participants (6514 men, mean age 62 year) who also underwent quantitative ultrasound of the heel. After a median follow-up of 7.5 years, there were 504 fractures of which 164 were hip fractures. In multivariable linear regression analysis, broadband ultrasound attenuation (BUA) was positively associated with total and leisure-time activities while showing no association with transportation and work activities. Home activities were associated with a lower BUA among younger participants. In multivariable Cox proportional-hazards models, moderate activities at home and in leisure time were associated with lower hip fracture risk among women (hazard ratios [HR] 0.51 and 0.55, p value 0.02 and 0.03, respectively). Among men, leisure-time activities were associated with lower risk of hip fracture (HR=0.58; p for trend<0.001) whereas activities at home were associated with higher risk of any fracture (HR=1.25; p for trend=0.008). Walking for leisure or transport was associated with lower risk of fracture in both men and women. Multivariable fractional polynomial modelling showed a U-shaped association between home activities and fracture risk especially among women. This study suggests that different domains of physical activity may relate differently to fracture risk and these relationships may vary by sex.

Association of physical exercise and calcium intake with bone mass measured by quantitative ultrasound

Background

Interventions other than medications in the management of osteoporosis are often overlooked. The purpose of this study was to investigate the association of physical activity and calcium intake with bone parameters.

Methods

We measured the heel T-score and stiffness index (SI) in 1890 pre- and postmenopausal women by quantitative ultrasound (QUS) and assessed physical activity and dietary calcium intake by questionnaire. Participants were divided according to their weekly physical activity (sedentary, moderately active, systematically active) and daily calcium consumption (greater than or less than 800 mg/day).

Results

SI values were significantly different among premenopausal groups (p = 0.016) and between sedentary and systematically active postmenopausal women (p = 0.039). QUS T-scores in systematically active premenopausal women with daily calcium intake > 800 mg/day were significantly higher than those in all other activity groups (p < 0.05) independent of calcium consumption.

Conclusions

Systematic physical activity and adequate dietary calcium intake are indicated for women as a means to maximize bone status benefits.

Use of quantitative ultrasonography for noninvasive surveillance of the third metacarpal bone in racing and training Thoroughbreds

OBJECTIVE-To use quantitative ultrasonography to evaluate the association between the speed of sound (SOS) at 9 sites in the third metacarpal bone (MCIII) of racing Thoroughbreds with workload accumulation and the effect that MCIII failure has on this association. ANIMALS-Sixty-two 2- and 3-year-old Thoroughbreds in racing condition. PROCEDURES-Cumulative work index (CWI) was used to calculate total workload (CWI(total)) and also 3 independent CWIs for the various gaits (ie, trot [CWI(trot)], gallop [CWI(gallop)], and race [CWI(race)]) used during training and racing. Speed of sound was monitored in horses during the 2007 racing season and compared with the CWIs via regression analysis. Sex, age, limb, and MCIII failure were included as covariates in the model. RESULTS-SOS was significantly associated with CWI(total) at 8 sites and with independent CWIs of the various gaits at all 9 sites. Progression of SOS in MCIIIs with workload differed significantly in horses with clinical signs of metacarpal bone failure, compared with results for horses with clinically normal MCIIIs, in 1 site by use of CWI(total) and in 5 sites by use of the independent CWIs for the various gaits. CONCLUSIONS AND CLINICAL RELEVANCE-These results indicated that SOS in the MCIII of racing Thoroughbreds followed a constant pattern of progression as workload accumulated. With the development of more precise quantitative ultrasonography devices, SOS corrected for amount of activity may be used to identify horses at risk of bone failure.

The association between physical activity and osteoporotic fractures: a review of the evidence and implications for future research

PURPOSE

Physical activity helps maintain mobility, physical functioning, bone mineral density (BMD), muscle strength, balance and, therefore, may help prevent falls and fractures among the elderly. Meanwhile, it is theoretically possible that physical activity increases risk of fractures as it may increase risk of falls and has only a modest effect on BMD. This review aims to assess the potential causal association between physical activity and osteoporotic fractures from an epidemiological viewpoint.

METHODS

As the medical literature lacks direct evidence from randomized controlled trials (RCTs) with fracture end points, a meta-analysis of 13 prospective cohort studies with hip fracture end point is presented. The current evidence base regarding the link between exercise and fracture risk determinants (namely, falls, BMD, and bone quality) are also summarized.

RESULTS

Moderate-to-vigorous physical activity is associated with a hip fracture risk reduction of 45% (95% CI, 31-56%) and 38% (95% CI, 31-44%), respectively, among men and women. Risk of falling is suggested to be generally reduced among physically active people with a potential increased risk in the most active and inactive people. Positive effects of physical activity on BMD and bone quality are of a questionable magnitude for reduction of fracture risk.

CONCLUSION

The complexity of relationship between physical activity and osteoporotic fractures points out to the need for RCTs to be conducted with fractures as the primary end point.

Exercise maintains bone density at spine and hip EFOPS: a 3-year longitudinal study in early postmenopausal women

It is an important aim in the prevention of osteoporosis to stop or decelerate bone loss during the early postmenopausal years. Here we report on results of the 3-year EFOPS exercise trial in osteopenic women. The exercise strategy emphasized low-volume high-resistance strength training and high-impact aerobics. Forty-eight fully compliant women (55.1+/-3.3 years) with no medication or illness affecting bone metabolism participated in the exercise group (EG); 30 women (55.5+/-3.0 years) served as non-training controls (CG). At baseline there were no significant between-group differences with respect to physical fitness, bone mineral density, pain and nutritional status. The training consisted of two group training and two home training sessions per week. The study participants of both groups were individually supplemented with calcium and vitamin D (cholecalciferol). Bone mineral density (BMD) was measured by DXA at the lumbar spine, proximal femur and distal forearm and by QCT at the lumbar spine. Speed of sound and broadband ultrasound attenuation were determined at the calcaneus by quantitative ultrasound (QUS). Pain frequency and intensity at different skeletal sites were assessed via questionnaire. After 38 months, the following within-group changes were measured: DXA lumbar spine, EG: 0.8% n.s.; CG: -3.3% P<0.001; QCT trabecular ROI, EG: 1.1% n.s; CG: -7.7% P<0.001; QCT cortical ROI, EG: 5.3% P<0.001; CG: -2.6% P<0.001; DXA total hip: EG: -0.2% n.s; CG -1.9%, P<0.001; DXA distal forearm, EG: -2.8% P<0.001; CG: -3.8% P<0.001; BUA, EG: -0.3% n.s; CG -5.4% P<0.001; SOS, EG: 0.3% n.s; CG -1.0% P<0.001. At year 3 between-group differences relative to the exercise group were: DXA lumbar spine: 4.1% P<0.001; QCT trabecular ROI: 8.8% P<0.001; QCT cortical ROI: 7.9% P<0.001; DXA total hip: 2.1%, P<0.001; DXA distal forearm: 1.0% n.s.; BUA: 5.8% P<0.05; SOS: 1.3% P<0.001. Pain frequency and intensity in the spine significantly decreased in the exercise group and increased in the control group, while no between-group differences were detected in the main joints. In summary, over a period of 3 years our low-volume/high-intensity exercise program was successful to maintain bone mineral density at the spine, hip and calcaneus, but not at the forearm.

Leisure physical activity is associated with quantitative ultrasound measurements independently of bone mineral density in postmenopausal women

The purpose of this study was to assess the magnitude of the relationship between leisure physical activity and bone status as measured either by an Achilles ultrasound bone densitometer (QUS) or dual-energy X-ray absorptiometry (DXA) in postmenopausal women. We studied 1162 French Canadian postmenopausal women, aged 33-84 years (mean age 58 years), for QUS parameters [broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI)] measured at the right calcaneus, and bone mineral density (BMD) measured at the lumbar spine and femoral neck. Multivariate regression analyses revealed that leisure physical activity level was an independent predictor of the heel QUS parameters and of femoral neck BMD. No such association was observed for BMD of the lumbar spine. Heel QUS parameters (BUA, SOS, SI) and femoral neck BMD adjusted for interfering covariables showed a statistically significant difference between sedentary (less than three sessions/month) and active women (three or more sessions/week) (P < or = 0.001). Furthermore, after adjusting each heel QUS parameters for the mean lumbar spine BMD value, the association observed between leisure physical activity and QUS remained significant. These results suggest that regular leisure physical activity could influence QUS parameters, independently of BMD, and that quantitative ultrasound could be a suitable outcome measure in exercise studies in postmenopausal women.

Speed of sound measurements of the third metacarpal bone in young exercising thoroughbred racehorses

The purpose of this longitudinal in-field study was to evaluate the influence of exercise, age, and gender on superficial cortical bone of the third metacarpal bone (MC III) in young Thoroughbreds by measuring speed of sound (SOS) values with an axial transmission technique (Omnisense, Sunlight Ltd, Israel). Both MC III of 75 racehorses, 2 to 4 years old, were monitored with SOS measurements in 5- to 7-week intervals during a 9- month physical exercise period. Medical data and training programs (slow gallop, canter, and high-speed work) of each horse were recorded. SOS measurements began before 2-year-old horses started high-speed training. SOS values of the dorsal aspect of MC III were significantly lower in comparison with values obtained at the lateral and the medial aspect of MC III, and SOS values were inversely correlated with measurement cycles. Significant limb-associated differences in dorsal MC III SOS values were observed at measurement cycles 2, 3, and 4. SOS values obtained at the lateral and medial aspect of MC III increased with age. SOS values obtained at the dorsal aspect of MC III, decreased with age. Mares had significantly higher SOS values at the dorsal aspect of MC III, when compared with corresponding values in stallions. In 2-year-old Thoroughbreds SOS values of the dorsal MC III were significantly different between cycles 1 and 2, between cycles 3 and 4, and between cycles 4 and 5. Three-year-old horses showed significant differences between SOS values of the dorsal MC III obtained at cycles 3 and 4. Training intensities did not significantly influence SOS values. The results indicate that young exercising Thoroughbred racehorses have age-, gender-, and measurement-cycle-dependent variations in SOS values of MC III, which probably reflect adaptive variations in superficial cortical bone properties of MC III.

Physical activity, falls, and fractures among older adults: a review of the epidemiologic evidence

OBJECTIVES

Assess the relationship between physical activity and risk for falls and osteoporotic fractures among older adults.

DESIGN

Review and synthesis of published literature.

MEASUREMENTS

We searched the literature using MEDLINE, Current Contents, and the bibliographies of articles identified. We included randomized controlled trials (RCT) of the effects of physical activity on the incidence of falls and case-control and prospective cohort studies of the association of physical activity with osteoporotic fracture risk. We also summarized mechanisms whereby physical activity may influence risk for falls and fractures.

RESULTS

Observational epidemiologic studies and randomized clinical trials evaluating the effectiveness of physical activity programs to prevent falls have been inconclusive. However, many studies have lacked adequate statistical power, and recent trials suggest that exercise, particularly involving balance and lower extremity strength training, may reduce risk of falling. There is consistent evidence from prospective and case-control studies that physical activity is associated with a 20-40% reduced risk of hip fracture relative to sedentary individuals. The few studies that have examined the association between physical activity and risk of other common osteoporotic fractures, such as vertebral and wrist fractures, have not found physical activity to be protective.

CONCLUSIONS

Epidemiologic studies suggest that higher levels of leisure time physical activity prevent hip fractures and RCTs suggest certain exercise programs may reduce risk of falls. Future research needs to evaluate the types and quantity of physical activity needed for optimal protection from falls and identify which populations will benefit most from exercise.

Quantitative ultrasound in postmenopausal osteoporosis

Ultrasound has been proposed as a low-cost, radiation-free method for osteoporosis assessment in postmenopausal women. Large prospective studies have shown that ultrasound parameters can be used for fracture risk estimate in this population, providing that adequate quality control is performed. The places of both ultrasound and the current gold standard method for bone assessment, dual energy x-ray absorptiometry, are still to be determined. Further studies are needed on the diagnosis of osteoporosis using ultrasound, because current diagnostic thresholds, designed by the World Health Organization, do not apply to this-new technology. Monitoring of skeletal changes and treatment effects by ultrasound cannot be recommended.

Comparison of calcaneal ultrasound and DXA in young women

PURPOSE

The purpose of the study was to assess quantitative ultrasound (QUS) parameters in collegiate female gymnasts, a population whose training incorporates high-impact loading, which is particularly osteogenic, and to determine the discriminative capacity of this relatively new radiation-free technique compared with bone densitometry in a young healthy population.

METHODS

We studied 19 collegiate gymnasts and 23 healthy controls undergoing regular weight-bearing activity, matched for age (gymnasts 19.2 +/- 1.2, controls 19.9 +/- 1.6 yr) and body weight (gymnasts 56.7 +/- 3.7, controls 57.7 +/- 7.8 kg). QUS parameters of the calcaneus (broadband ultrasound attenuation (BUA), bone velocity (BV), and speed of sound (SOS)) were measured by a Walker Sonix UBA 575+. Bone mineral density (BMD; g x cm(-2)) of the lumbar spine, hip (femoral neck, trochanter, Ward's triangle) and whole body was assessed by dual energy x-ray absorptiometry (DXA, Hologic QDR 1000/W). Data analysis included unpaired two-tailed Student's t-tests, analysis of variance, Pearson product-moment, and Spearman rank-order correlations.

RESULTS

Regional and whole body BMD of gymnasts was greater than controls (P < 0.001), with the difference being 7-28%. Average QUS parameters of the right and left calcaneus were also higher (P < 0.001) in the gymnasts. BUA, BV, and SOS were significantly (P < 0.001) correlated to each bone site with r = 0.54-0.79. Analysis of receiver operating characteristic (ROC) curves indicated no significant difference in sensitivity and specificity for QUS and DXA measures.

CONCLUSIONS

These results indicate that QUS parameters of the calcaneus are higher in young women gymnasts compared to individuals who undergo regular weight-bearing activity and that QUS parameters are able to discriminate between these two groups in a similar manner as does regional and whole body BMD.

Effects of high-impact exercise on ultrasonic and biochemical indices of skeletal status: A prospective study in young male gymnasts

Physical activity has been proposed as one strategy to enhance bone mineral acquisition during growth. The aim of this study was to determine whether frequent impact loading associated with gymnastics training confers a skeletal benefit on pre- and peripubertal male gymnasts. We measured broadband ultrasonic attenuation (BUA, dB/MHz) at the calcaneus (CBUA); ultrasound velocity (m/s) at the calcaneus (CVOS), distal radius (RVOS) and phalanx (PVOS); serum osteocalcin (OC); total alkaline phosphatase (ALP) and insulin-like growth factor-I (IGF-I) every 3-4 months over an 18-month period in elite male gymnasts and matched normoactive controls (pubertal stage </=2). Ground reaction forces of common gymnastics maneuvers were determined using a force platform and loading histories of the upper and lower extremities approximated from video recordings. Ultrasound results were expressed as a standardized score (Z score) adjusted for age, height, and weight. At baseline, no differences were detected between the gymnasts (n = 31) and controls (n = 50) for CBUA, although ultrasound velocity at each site was higher in the gymnasts (0.6-1.5 SD) than the predicted mean in controls (p </= 0. 001). Over 18 months, CBUA Z scores increased significantly in the gymnasts from baseline (0.3 vs. 1.0, p < 0.05, n = 18). In contrast, ultrasound velocity did not increase in either group, although CVOS and RVOS remained significantly higher in gymnasts compared with controls (range p < 0.01 and < 0.001). No differences between groups were found for OC, ALP, or IGF-I at any time. Gymnastics training was associated with on average 102 and 217 impacts per session on the upper and lower extremities, respectively, with peak magnitudes of 3.6 and 10.4 times body weight. These results suggest that frequent high-impact, weight-bearing exercise during the pre and peripubertal period may enhance the mechanical competence of the skeleton, perhaps offering an important strategy for osteoporosis prevention if the benefits are maintained.

The role of quantitative ultrasound in the assessment of bone: a review

Quantitative ultrasound (QUS) bone measurement is a promising, relatively new technique for the diagnosis of osteoporosis. Unlike to the more established method of bone densitometry [measurement of bone mineral density (BMD) e.g. using dual X-ray absorptiometry (DEXA)], QUS does not use ionizing radiation. It is cheaper, takes up less space and is easier to use than densitometry techniques. The two QUS parameters currently measured are broadband ultrasound attenuation (BUA) and speed of sound (SOS). The reported age-related changes for healthy women range from -0.27% to -1.62% per year for BUA and from -0.06% to -0.19% per year for SOS. Precision ranges from 1.0 to 3.8% (CV) for BUA and from 0.19 to 0.30% (CV) for SOS. The new method of imaging ultrasound has improved the precision of QUS measurements. QUS is significantly correlated with BMD. Studies with the latest equipment have shown r-values between 0.6 and 0.9 in site-specific measurements, and QUS is thus believed to reflect mainly BMD. However, other studies indicate that QUS measures something other than the actual mineral content of bone, namely bone quality, e.g. in vitro studies have shown that QUS reflects trabecular orientation independently of BMD. In both cross-sectional and prospective studies, QUS seems to be as good a predictor of osteoporotic fractures as BMD. In two large prospective studies, QUS also predicted fracture risk independently of BMD. QUS has just begun to be used systematically for monitoring the response to anti-osteoporotic treatments in prospective trials. In the studies performed, QUS has been found to be useful in the follow-up of patients. QUS is thus a promising new technique for bone assessment.

What is the optimal type of physical activity to enhance health?

This review examines the potential of active daily living as a means of gaining the cardiovascular and health rewards previously sought through vigorous aerobic fitness programmes. Cross-sectional studies of occupational and leisure activity show encouraging associations between such activity and good health; in workers, the gross intensity of effort needed for health benefits has seemed to be 20 kJ/min. There has been less unanimity on the threshold intensity needed in leisure activities, but various recent "position statements" have decreased the recommendation to 50% of an individual's maximal oxygen intake, sustained for one hour three to five times per week. Life-style activities such as walking seem likely to reach this intensity in older individuals, but are unlikely to do so in young adults. A growing number of controlled longitudinal studies of walking programmes have demonstrated gains in aerobic fitness, modest reductions in blood pressure, improvements in lipid profile, increased bone density, and enhanced mood state, with less consistent reductions of body fat. However, gains have been greatest in the elderly, sedentary, and obese populations. The main component of active living, fast walking, seems likely to enhance health in such populations, but it is unlikely to be effective in young adults who are in good initial health.

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.

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 effect of ankle oedema on bone ultrasound assessment at the heel

Relatively inexpensive, portable bone ultrasound systems are of particular relevance to disabled or elderly subjects, who may have problems with access to other forms of densitometry. The effects of local soft tissues on ultrasound measurements are poorly understood and, as ankle oedema is common in such subjects, we examined its consequences for bone ultrasound readings at the heel. Eleven elderly subjects (mean age 81 years) with below-knee pitting oedema were assessed using a direct-contact bone ultrasound system (CUBA Clinical). We made a total of 16 series of readings, 6 unilateral and 5 bilateral. In each series an initial reading was followed by repeated pressure over the measurement site to disperse oedema; subsequent readings were thus subject to a progressively lessening degree of local oedema, until a steady state was eventually reached in which no further oedema could be displaced. Heel width fell by a mean of 6.3 mm between initial and steady-state readings; consistent with the clinical appearance of moderate oedema, pitting to a mean depth of only 3.15 mm. Measurements in the presence of oedema were compared with those after its elimination, and oedema was shown to cause a mean reduction of 23.9 m/s in velocity of sound (VOS) and of 5.5 dB/MHz in broadband ultrasound attenuation (BUA). Both changes were equivalent to a fall by a quarter of one standard deviation of the reference range, and were significant at p < 0.05 on paired t-test. As the severity of oedema will vary through the day, and from day to day, measurement protocols for bone ultrasound should pay attention to the confounding effects of oedema.

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.

The nonlinear transition period of broadband ultrasound attenuation as bone density varies

The purpose of this study was to determine whether a transition period occurs between cortical and cancellous bone in the relationship between ultrasound parameters [broadband ultrasound attenuation (BUA) and ultrasonic velocity] and density. Twenty-two cancellous bone discs wee obtained from proximal bovine tibiae. Also included were three samples of human vertebral cancellous bone from an elderly female and four samples of bovine cortical bone. Ultrasonic velocity did not show any transition period as density varied from cancellous to cortical bone. Ultrasonic velocity exhibited a definite linear dependence on density over the entire range examined. However, BUA has shown a transition period as density varied. Although BUA increased linearly with density for a low density cancellous bone tested (below 0.64 g cm-3), the dependence of BUA on density is nonlinear with a downwardly inflected parabola shape when covering a wide density range (0.130-0.913 g cm-3) of cancellous bone. When one includes cortical bone, the parabola tends to level off in a slow exponential decay. This nonlinear dependence may help to understand the characteristics of BUA measurement.

Effect of physical activity as a caddie on ultrasound measurements of the Os calcis: a cross-sectional comparison

This cross-sectional study investigated the effect of long-term activity as a caddie on ultrasonic properties of the os calcis. We measured 74 healthy women, age 20-59 years, who worked at a golf course as caddies. An age-matched control group of 433 healthy women, who were office workers or housewives, also were recruited for comparison. The ultrasound measurements were performed with an Achilles ultrasound densitometer. The quadriceps muscle strength and the hand grip strength were measured in a perimenopausal subgroup (45-59 years) of the caddies and a subgroup of controls matched for age, height, weight, and body mass index. Urinary pyridinoline and deoxypyridinoline were also measured in these perimenopausal subgroups. Caddies had significantly higher ultrasound values than controls in the 40-49 (stiffness index, 101.6 +/- 12.9% versus 87.9 +/- 11.9%; p < 0.0001) and 50-59 (stiffness index, 90.5 +/- 11.6% versus 77.2 +/- 11.6%; p < 0.0001) age-stratified groups. Quadriceps strength and grip strength were significantly higher in caddies than those in controls. In postmenopausal caddies, all ultrasound values were significantly higher than for controls. In caddies there were not significant decreases of any ultrasound values with postmenopausal age. Even for the subgroup within 3 years of menopause there were significant differences between caddies and controls (p < 0.01). There were no significant increases of pyridinoline and deoxypyridinoline after menopause in the caddies. We demonstrated that the caddies had higher ultrasound properties of the os calcis and lower bone resorption after menopause compared with controls.

Ultrasound velocity changes at the proximal phalanxes of the hand in pre-, peri- and postmenopausal women

We evaluated the bone tissue modifications which occur in pre-, peri- and postmenopausal women by means of an ultrasound (US) device which measures US propagation velocity in the distal metaphysis of the proximal phalanxes of the hand. Before starting the study, two operators assessed the in vivo short-term precision of the device in 12 volunteers, each measured 10 times (5 times by each operator). Then the US velocity in the dominant (DO) and non-dominant (ND) hand was measured in 228 women to evaluate whether there was a difference between US values measured at these sites. Finally, another selected group of 417 healthy pre-, peri- and postmenopausal women, aged from 40 to 65 years, was studied to evaluate the physiological climacteric changes in the US parameter measured: amplitude-dependent speed of sound (AD-SoS). In the 12 volunteers, intra- and inter-observer short-term precision (CV) was 0.4% (for both the operators) and 1.0%, respectively. DO and ND hand AD-SoS values (2074.1 +/- 63.8 m/s and 2077.1 +/- 65.5 m/s, respectively) proved to be highly correlated (r = 0.96, p < 0.0001) in the 228 women studied. AD-SoS distribution (417 subjects) was correlated with age, climacteric condition (premenopause with regular or irregular cycles and natural postmenopause) and body mass index (BMI). In premenopause (253 subjects) the US velocity was higher among women with regular cycles (2107.2 +/- 48.5 m/s) than among those with irregular cycles (2074.7 +/- 44.1 m/s) (p < 0.0001). In postmenopause (164 subjects) an inverse correlation between AD-SoS and the time elapsed since menopause was found (r = -0.42, p < 0.0001). Furthermore, age and BMI were shown to be inversely related to AD-SoS (r = -0.47, p < 0.0001 and r = -0.30, p < 0.0001, respectively) when evaluated in the whole study group. The results obtained confirm that US transmission at the phalanxes is sensitive to pre-, peri- and postmenopausal bone changes. Further studies are needed to evaluate its ability to predict osteoporotic fracture risk.

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).

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.

Quantitative ultrasound: a technique to target women with low bone mass for preventive therapy

Assessment of bone mass is the best predictor of fracture. The current challenge is to develop a strategy to determine which women should be targeted for preventive therapy. The cost of dual-energy x-ray absorptiometry equipment precludes its widespread availability in physicians' offices and clinics. Quantitative ultrasound appears to offer a low-cost alternative method to assess bone mass and fracture risk. In addition, ultrasound is radiation free. Quantitative ultrasound values decrease with age, are lower in osteoporotic women, and are influenced by estrogen treatment. The associations observed between quantitative ultrasound and fracture indicate that it is comparable to densitometry in predicting fracture risk. This association remains significant after correction for bone mineral density, suggesting that ultrasound measures additional properties of bone that are determinants of strength. Quantitative ultrasound may prove to be a technique that will allow bone mass testing to become more readily available to the population. The ability of quantitative ultrasound to discriminate those women at greatest risk for fracture will allow physicians to target those women for preventive therapy.

Age-related changes in Os calcis ultrasonic indices: a 2-year prospective study

We performed repeated ultrasound measurements approximately 2 years apart (average 23 months +/- 3 months) on the os calcis of 113 healthy postmenopausal women recruited from two large prospective cohort studies named OFELY and EPIDOS. Group A (from OFELY) consisted of 88 women aged 52-72 (63 +/- 5) years, randomly selected from a large insurance company, and group B (from EPIDOS) consisted of 25 women aged 75-88 (80 +/- 4) years, randomly selected from the voting lists. We obtained broadband ultrasonic attenuation (BUA) and speed of sound (SOS) measurements, as well as the Stiffness index, with a Lunar Achilles ultrasound machine. We performed dual energy X-ray absorptiometry (DXA) measurements of femoral neck bone mineral density (neck BMD) with a Hologic QDR 2000 for group A and with a Lunar DPX Plus for group B. The decrease that we observed over 2 years was on average +/- 1 SD: -1.01 +/- 4.6 dB/MHz (p = 0.02) for BUA (which is approximately equal to the long-term precision error in vitro), -11.3 +/- 9.2 m/s (p = 0.0001) for SOS (approximately 5 times the precision error), -3.8 +/- 4.2% YA (p = 0.0001) for Stiffness (2.5 times the precision error) and -0.01 +/- 0.03 g/cm2 (p = 0.0001) for neck BMD (approximately equal to the precision error). In terms of percentage change this represents: -1.0% +/- 4.3% for BUA, -0.8% +/- 0.6% for SOS and -1.85% +/- 4.4% for neck BMD. At the individual level, most SOS and Stiffness values were consistent with a decrease, whereas BUA and neck BMD values were spread out above and below the zero line of no change. The decreases in SOS and Stiffness were significantly larger in the early postmenopause (< or = 20 years since menopause [YSM]) than in the late postmenopause (> 20 YSM). We observed a similar trend for BUA and BMD but this did not reach statistical significance. We found a weak but significant correlation between changes in ultrasound variables and changes in neck BMD. However, the 2-year changes observed in SOS were not significantly correlated with changes in BUA. This study suggests that the heel ultrasound measurements of SOS and Stiffness are valuable indices of postmenopausal bone loss, and could be used for follow-up in therapeutic trials.

Walking at work and bone mineral density of premenopausal women

The objective of this cross-sectional study was to determine whether habitual physical activity such as daily walking at work affects bone mineral density (BMD) in healthy premenopausal women. Thirty-one letter or newspaper carriers and 30 sedentary (non-exercising) office workers were screened out from 167 subjects working in the public post office and a private newspaper publishing company. BMD was measured with a dual-energy X-ray densitometer at the lumbar spine (L2-4), femoral neck, distal femur, patella, proximal tibia, calcaneus and distal radius. In addition, maximal isometric strength, cardiorespiratory fitness, anthropometry, 4-day dietary record and daily occupational work load were assessed. During one work shift the carriers' mean walking distance was 5926 m, with 68 flights of stairs walked, and their mean heart rate was 105 beats/min (114 beats/min during the delivery). The corresponding figures for the office workers were significantly lower: 1895 m, 10 flights and 82 beats/min, respectively. Neither the BMD values adjusted for body mass index (kg/m2) and calcium intake nor the indices of physical performance capacity showed significant differences between the groups. Consequently, habitual daily walking and stair climbing by healthy premenopausal women appeared to be insufficient exercise stimulus to increase considerably the BMD or aerobic and muscular fitness above the values found in a comparable group of sedentary office workers.

Age-associated changes in ultrasound measurements of the calcaneus in men and women: the Rotterdam Study

Broadband ultrasound attenuation (BUA) and speed of sound (SOS) of the os calcis were measured in a sample of 1405 persons (628 men), aged 55-93 years, from the cohort of the Rotterdam Study, a population-based study of diseases in the elderly. We studied the effect of age, body mass index, age at menopause, current use of thiazides, loop diuretics, and estrogens, smoking, and disability on SOS and BUA. Comparisons were made between ultrasound measurements and bone mineral density (BMD) measurements of the lumbar spine and proximal femur using DXA. We found a significant decline with age in SOS and BUA in men (-0.4 and -0.1 %/year, respectively) and women (-1.3 and -0.4%/year, respectively), which persisted after adjustment for body mass index. Age at menopause was not associated with SOS or BUA. Pack-years of smoking was negatively related to SOS in both sexes and to BUA in men. Severe disability was associated with lower SOS and BUA in men, but not in women. Despite the small number of exposed persons, current corticosteroid use was associated with lower BUA in men. The other risk factors examined did not affect the ultrasound measurements. We observed modest correlations between SOS or BUA, on the one hand, and BMD of the lumbar spine, on the other hand (r = 0.32-0.42). Similar correlations were found between ultrasound measurements and BMD measurements of the proximal femur. We conclude that in persons 55 years or over (1) there is a significant age-related decline of BUA and SOS, which is about three times higher in women compared with men, and (2) ultrasound measurements are not able to predict low BMD in hip or spine.

Quantitative ultrasound of the heel: correlation with densitometric measurements at different skeletal sites

To assess the utility of quantitative ultrasound (QUS) of the heel for osteoporosis screening, we studied a group of 170 early postmenopausal women using both QUS of the heel and dual-energy X-ray absorptiometry (DXA) at the spine, hip, forearm, and whole body. On the basis of the linear regression results between QUS and DXA, a 95% bone mineral density (BMD) estimate confidence range was defined. Correlation coefficients between the QUS measurements and DXA ranged from 0.26 to 0.63. The confidence ranges for the estimated BMD based on a QUS measurement of the heel were large, such that an estimation of skeletal BMD at any of the DXA sites measured was not possible. For example, an estimate of the normative anteroposterior spine BMD (i.e. the T-score or the Z-score) based on a calcaneal ultrasound reading would have an error of +/- 1.9 standard deviations. Results for predicting the normative BMD of the other DXA regions were similar, with expected errors ranging from +/- 1.4 to +/- 2.0 standard deviations. We therefore conclude that QUS is not suited for the screening of early postmenopausal women for low axial or peripheral BMD. However, QUS may have a role as an independent predictor of fracture by measuring skeletal properties in addition to bone density.

Physical activity and bone mass: exercises in futility?

Growing bone responds to low or moderate exercise through significant additions of new bone in both cortical and trabecular moieties and results in adaptation through periosteal expansion and endocortical contraction. Intracortical activation frequency declines in growing bone in response to exercise, reducing porosity and the remodelling space. These adaptations can be maintained into and throughout adulthood. Young bones have a greater potential for periosteal expansion than aging bone, allowing them to adapt more rapidly and efficiently to an acute need for increased strength, but a threshold level of activity exists above which some bones respond negatively by suppressing normal growth and modelling activity, reducing geometric, mechanical and material properties in cortical and trabecular bone. From cross-sectional studies, differences in bone mass between exercising and non-exercising adults are generally less than 10%, but do not account for exercise history which may be very important, and often fail to consider important confounding variables. There is sufficient longitudinal data to demonstrate that moderate to intensive training can bring about modest increases of about 1-3% in bone mineral content (BMC) of men and premenopausal women. In young adults very strenuous training may increase BMC of the tibia up to 11% and its bone density (BD) by 7%, but may represent periosteal woven bone formation in response to excessive strain. Some evidence shows that exercise can also add bone mass to the post-menopausal skeleton, although the amounts are site-specific and relatively modest. Increases as high as 5-8% can be found after 1-2 years of intensive exercise, but additions of bone to the femur and radius are generally less than 2%, well within the range of the remodelling space and measurement precision. Although increases in bone mass of the post-menopausal skeleton may be extremely modest, physical activity is important to preserve bone mass and muscle function. Detraining reduces any bone mass increase to pre-existing values so that long-term benefits are only retained with continuing exercise. Most importantly, the amount of bone gain that can be achieved appears dependent primarily on the initial bone mass suggesting that individuals with extremely low initial bone mass may have more to gain from exercise than those with moderately reduced bone mass.

Muscle ultrasonography and computed tomography in elderly trained and untrained women

Ultrasonography (US) and computed tomography (CT) were compared in studying the associations between long-term physical training and quadriceps muscle mass and structure in female athletes and controls, aged 66-85 years. Muscle cross-sectional area (CSA) measured using US correlated highly with that measured using CT, but the latter technique yielded 30% higher values on average. The echo intensity of the fasciae and bone measured by US correlated positively with the mean radiological density and negatively with the relative proportion of fat obtained from CT. Low intramuscular echo intensity was accompanied by high muscle density and low relative proportion of fat. The athletes had larger quadriceps CSA and more discerned fasciae and connective tissue septa but less fat than the controls. The results indicate that US and CT both are useful methods in comparing muscle mass and structure in elderly trained and untrained women.