The Influence of High-Impact Exercise on Cortical and Trabecular Bone Mineral Content and 3D Distribution Across the Proximal Femur in Older Men: A Randomized Controlled Unilateral Intervention

Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running

To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and β-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17β-oestradiol, progesterone, P1NP and β-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17β-oestradiol concentrations (pg·ml-1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p =  < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml-1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml-1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). β-CTX-1 concentrations (ng·ml-1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.

Non-pharmacological and pharmacological treatments for bone health after stroke: Systematic review with meta-analysis

BACKGROUND

Hemi-osteoporosis is a common secondary complication of stroke. No systematic reviews of pharmacological and non-pharmacological agents for post-stroke bone health have estimated the magnitude and precision of effect sizes to guide better clinical practice.

OBJECTIVES

To examine the benefits and harms of pharmacological and non-pharmacological agents on bone health in post-stroke individuals.

METHODS

Eight databases were searched (PubMed, Cochrane library, Scopus, CINAHL Complete, Embase, PEDro, Clinicaltrils.gov and ICTRP) up to June 2023. Any controlled studies that applied physical exercise, supplements, or medications and measured bone-related outcomes in people with stroke were included. PEDro and the GRADE approach were used to examine the methodological quality of included articles and quality of evidence for outcomes. Effect sizes were calculated as standardized mean differences (SMD) and risk ratio (RR). Review Manager 5.4 was used for data synthetization.

RESULTS

Twenty-four articles from 21 trials involving 22,500 participants (3,827 in 11 non-pharmacological and 18,673 in 10 pharmacological trials) were included. Eight trials were included in the meta-analysis. The methodological quality of half of the included non-pharmacological studies was either poor or fair, whereas it was good to excellent in 8 of 10 pharmacological studies. Meta-analysis revealed a beneficial effect of exercise on the bone mineral density (BMD) of the paretic hip (SMD: 0.50, 95 % CI: 0.16; 0.85; low-quality evidence). The effects of anti-resorptive medications on the BMD of the paretic hip were mixed and thus inconclusive (low-quality evidence). High-quality evidence showed that the administration of antidepressants increased the risk of fracture (RR: 2.36, 95 % CI 1.64-3.39).

CONCLUSION

Exercise under supervision may be beneficial for hip bone health in post-stroke individuals. The effect of anti-resorptive medications on hip BMD is uncertain. The adverse effects of antidepressants on fracture risk among post-stroke individuals warrant further attention. Further high-quality studies are required to better understand this issue.

REGISTRATION

PROSPERO CRD42022359186.

Evaluation of bone-related mechanical properties in female patients with long-term remission of Cushing's syndrome using quantitative computed tomography-based finite element analysis

BACKGROUND

Hypercortisolism in Cushing's syndrome (CS) is associated with bone loss, skeletal fragility, and altered bone quality. No studies evaluated bone geometric and strain-stress values in CS patients after remission thus far.

PATIENTS AND METHODS

Thirty-two women with CS in remission (mean age [±SD] 51 ± 11; body mass index [BMI], 27 ± 4 kg/m2; mean time of remission, 120 ± 90 months) and 32 age-, BMI-, and gonadal status-matched female controls. Quantitative computed tomography (QCT) was used to assess volumetric bone mineral density (vBMD) and buckling ratio, cross-sectional area, and average cortical thickness at the level of the proximal femur. Finite element (FE) models were generated from QCT to calculate strain and stress values (maximum principal strain [MPE], maximum strain energy density [SED], maximum Von Mises [VM], and maximum principal stress [MPS]). Areal BMD (aBMD) and trabecular bone score (TBS) were assessed by dual-energy X-ray absorptiometry (2D DXA).

RESULTS

Trabecular vBMD at total hip and trochanter were lower in CS as compared with controls (P < .05). Average cortical thickness was lower, and buckling ratio was greater in CS vs controls (P < .01). All strain and stress values were higher in CS patients vs controls (P < .05). 2D DXA-derived measures were similar between patients and controls (P > .05). Prior hypercortisolism predicted both VM (β .30, P = .014) and MPS (β .30, P = .015), after adjusting for age, BMI, menopause, delay to diagnosis, and duration of remission.

CONCLUSIONS

Women with prior hypercortisolism have reduced trabecular vBMD and impaired bone geometrical and mechanical properties, which may contribute to an elevated fracture risk despite long-term remission.

Changes in femoral neck bone mineral density and structural strength during a 12-month multicomponent exercise intervention among older adults - Does accelerometer-measured physical activity matter?

Age-related bone loss is to some extent unavoidable, but it may be decelerated with regular exercise continued into older age. Daily physical activity alongside structured exercise may be an important stimulus for maintaining bone strength, but the relationships of habitual physical activity with bone strength are sparsely investigated in older adults. Therefore, the main aim was to investigate if accelerometer-derived impact-based and intensity-minute-based measures of physical activity were associated with changes in femoral neck bone traits during a 12-month exercise intervention among community-dwelling older men and women. Data comes from the PASSWORD study (ISRCTN52388040), a year-long multicomponent exercise intervention. Participants were 299 older adults (mean age 74 ± 4 years, 58 % women), who self-reported not to meet the physical activity guidelines for older adults but did not have any contraindications for exercising. The multicomponent training program included both supervised and self-administered exercises aimed at improving muscle strength, postural balance, and aerobic endurance. Physical activity was assessed at baseline and at six months into the intervention, and femoral neck bone properties at baseline and at twelve months. Physical activity measures were accelerometer-measured mean daily osteogenic index score, low, medium, and high intensity impact counts, and sedentary, light, and moderate-to-vigorous intensity activity minutes. Femoral neck bone mineral density (BMD) was measured with DXA and structural strength indicators (cross-sectional area [CSA] and section modulus) were subsequently derived from hip structural analysis. Longitudinal associations of physical activity and bone outcomes were analyzed with generalized estimating equation linear models. Sex was included as a moderating factor, and models were further adjusted by potentially confounding factors (age, height, weight, smoking status, medications, chronic disease conditions, and strength training adherence). Participants increased their physical activity by all measures and decreased their sedentary time from baseline to six months. BMD decreased from baseline to post-intervention, while CSA maintained stable and section modulus slightly increased. Osteogenic index, high impacts, and moderate-to-vigorous intensity physical activity, measured across the first half of the study, were positively associated with changes in BMD over 12 months (time х physical activity interaction effect: ß = 0.065, 95 % CI [0.004, 0.126]; ß = 0.169, 95 % CI [0.048, 0.289]; and ß = 0.151, 95 % CI [0.016, 0.286], respectively). That is, the higher the physical activity was, the smaller was the decline in BMD. Any physical activity measure was not associated with changes in CSA or section modulus in the full study sample. Sex did not significantly moderate the longitudinal associations, except the association between sedentary time and CSA (sex х time х PA interaction effect: ß = -0.017, 95 % CI [-0.033, -0.002]). An inverse association was found between sedentary time and changes in CSA in women, but not in men. In conclusion, BMD decline was less pronounced in individuals who accumulated more accelerometer-measured daily physical activity at the intensity of very brisk walking or light lateral jumping or higher intensities in a sample of relatively healthy, previously physically inactive older adults. Our findings support that accumulating the recommended amount of 150 or more weekly minutes of moderate-to-vigorous physical activity is also beneficial for older adults' bone health when incorporated into a multicomponent exercise program.

Skeletal site-specific effects of jump training on bone mineral density in adults: a systematic review and meta-analysis

Preserving or preventing declines in bone mineral density (BMD) is imperative. As jumping is a high-impact bone-loading action, this meta-analysis evaluated the efficacy of jump training to improve BMD and bone turnover relative to non-jumping controls in men and women > 18 years, following Preferred Reported Items for Systematic Reviews and Meta-Analysis guidelines. PubMed and COCHRANE Library databases were searched until February 2022. Fifteen articles (19 jumping-trials) met the predetermined search criteria. Eighteen trials were included for BMD data (n = 666 participants). There was a significant small-moderate effect of jumping on femoral neck BMD (%mean difference: 95%CI, +1.50%: 0.83%; 2.17%, p < 0.0001), that remained significant after sub-analysis by age for both younger (+1.81%: 0.98%; 2.65%) and older adults (+1.03%: 0.02%; 2.03%). BMD of total hip (+1.26%: 0.56%; 1.96% vs + 0.06%: -0.96%; 1.08%), and trochanter (+0.84%: 0.20%; 1.48% vs -0.16%: -1.08%; 0.76%) increased significantly with jump training only in younger adults and non-significantly at the lumbar spine (+0.84%: -0.02%; 1.7% vs -0.09%: -0.96%; 0.77%) only in younger but not older adults, respectively. The BMD response to jump training appears to be site-specific, with the highest sensitivity at the femoral neck. No dose-response effect suggests moderate certainty of a gain in femoral neck BMD when performing the median jump-load of 50 jumps four times weekly.

Effects of Moderate- to High-Impact Exercise Training on Bone Structure Across the Lifespan: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Moderate- to high-impact exercise improves bone mineral density (BMD) across the lifespan, but its effects on bone structure, which predicts fracture independent of areal BMD, are unclear. This systematic review and meta-analysis investigated effects of impact exercise on volumetric BMD (vBMD) and bone structure. Four databases (PubMed, Embase, SPORTDiscus, Web of Science) were searched up to March 2022 for randomized controlled trials (RCTs) investigating the effects of impact exercise, with ground reaction forces equal to or greater than running, compared with sham or habitual activity, on bone vBMD and structure. Bone variables were measured by quantitative computed tomography or magnetic resonance imaging at the tibia, radius, lumbar spine, and femur. Percentage changes in bone variables were compared among groups using mean differences (MD) and 95% confidence intervals (CI) calculated via random effects meta-analyses. Subgroup analyses were performed in children/adolescents (<18 years), adults (18-50 years), postmenopausal women, and older men. Twenty-eight RCTs (n = 2985) were included. Across all studies, impact exercise improved trabecular vBMD at the distal tibia (MD = 0.54% [95% CI 0.17, 0.90%]), total vBMD at the proximal femur (3.11% [1.07, 5.14%]), and cortical thickness at the mid/proximal radius (1.78% [0.21, 3.36%]). There was no effect on vBMD and bone structure at the distal radius, femoral shaft, or lumbar spine across all studies or in any subgroup. In adults, impact exercise decreased mid/proximal tibia cortical vBMD (-0.20% [-0.24, -0.15%]). In postmenopausal women, impact exercise improved distal tibia trabecular vBMD (0.79% [0.32, 1.25%]). There was no effect on bone parameters in children/adolescents in overall analyses, and there were insufficient studies in older men to perform meta-analyses. Impact exercise may have beneficial effects on bone structure and vBMD at various skeletal sites, but additional high-quality RCTs in different age and sex subgroups are needed to identify optimal exercise protocols for improving bone health across the lifespan. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Bone density changes after five or more years of unilateral lower extremity osseointegration: Observational cohort study

Context

Rehabilitation following lower extremity amputation presents multiple challenges, many related to the traditional prosthesis (TP) socket. Without skeletal loading, bone density also rapidly decreases. Transcutaneous osseointegration for amputees (TOFA) surgically implants a metal prosthesis attachment directly into the residual bone, facilitating direct skeletal loading. Quality of life and mobility are consistently reported to be significantly superior with TOFA than TP.

Objective

To investigate how femoral neck bone mineral density (BMD, g/cm²) changes for unilateral transfemoral and transtibial amputees at least five years following single-stage press-fit osseointegration.

Methods

Registry review was performed of five transfemoral and four transtibial unilateral amputees who had dual x-ray absorptiometry (DXA) performed preoperatively and after at least five years. The average BMD was compared using Student's t-test (significance p < .05). First, all nine Amputated versus Intact limbs. Second, the five patients with local disuse osteoporosis (ipsilateral femoral neck T-score < -2.5) versus the four whose T-score was greater than -2.5.

Results

The average Amputated Limb BMD was significantly less than the Intact Limb, both Before Osseointegration (0.658 ± 0.150 vs 0.929 ± 0.089, p < .001) and After Osseointegration (0.720 ± 0.096 vs 0.853 ± 0.116, p = .018). The Intact Limb BMD decreased significantly during the study period (0.929 ± 0.089 to 0.853 ± 0.116, p = .020), while the Amputated Limb BMD increased a not statistically significant amount (0.658 ± 0.150 to 0.720 ± 0.096, p = .347). By coincidence, all transfemoral amputees had local disuse osteoporosis (BMD 0.545 ± 0.066), and all transtibial patients did not (BMD 0.800 ± 0.081, p = .003). The local disuse osteoporosis cohort eventually had a greater average BMD (not statistically significant) than the cohort without local disuse osteoporosis (0.739 ± 0.100 vs 0.697 ± 0.101, p = .556).

Conclusions

Single-stage press-fit TOFA may facilitate significant BMD improvement to unilateral lower extremity amputees with local disuse osteoporosis.

Relationship between Football-Specific Training Characteristics and Tibial Bone Adaptation in Male Academy Football Players

We examined the relationship between football-specific training and changes in bone structural properties across a 12-week period in 15 male football players aged 16 years (Mean ± 1 SD = 16.6 ± 0.3 years) that belonged to a professional football academy. Tibial scans were performed at 4%, 14% and 38% sites using peripheral quantitative computed tomography immediately before and 12 weeks after increased football-specific training. Training was analysed using GPS to quantify peak speed, average speed, total distance and high-speed distance. Analyses were conducted with bias-corrected and accelerated bootstrapped 95% confidence intervals (BCa 95% CI). There were increases in bone mass at the 4% (mean ∆ = 0.15 g, BCa 95% CI = 0.07, 0.26 g, g = 0.72), 14% (mean ∆ = 0.04 g, BCa 95% CI = 0.02, 0.06 g, g = 1.20), and 38% sites (mean ∆ = 0.03 g, BCa 95% CI = 0.01, 0.05 g, g = 0.61). There were increases in trabecular density (4%), (mean ∆ = 3.57 mg·cm^-3, BCa 95% CI = 0.38, 7.05 mg·cm^-3, g = 0.53), cortical dentsity (14%) (mean ∆ = 5.08 mg·cm^-3, BCa 95% CI = 0.19, 9.92 mg·cm^-3, g = 0.49), and cortical density (38%) (mean ∆ = 6.32 mg·cm^-3, BCa 95% CI = 4.31, 8.90 mg·cm^-3, g = 1.22). Polar stress strain index (mean ∆ = 50.56 mm³, BCa 95% CI = 10.52, 109.95 mm³, g = 0.41), cortical area (mean ∆ = 2.12 mm², BCa 95% CI = 0.09, 4.37 mm², g = 0.48) and thickness (mean ∆ = 0.06 mm, BCa 95% CI = 0.01, 0.13 mm, g = 0.45) increased at the 38% site. Correlations revealed positive relationships between total distance and increased cortical density (38%) (r = 0.39, BCa 95% CI = 0.02, 0.66), and between peak speed and increased trabecular density (4%) (r = 0.43, BCa 95% CI = 0.03, 0.73). There were negative correlations between total (r = -0.21, BCa 95% CI = -0.65, -0.12) and high-speed distance (r = -0.29, BCa 95% CI = -0.57, -0.24) with increased polar stress strain index (38%). Results suggest that despite football training relating to increases in bone characteristics in male academy footballers, the specific training variables promoting adaptation over a 12-week period may vary. Further studies conducted over a longer period are required to fully elucidate the time-course of how certain football-specific training characteristics influence bone structural properties.

Exercise to Prevent and Manage Frailty and Fragility Fractures

PURPOSE OF REVIEW

This review identifies exercise-based recommendations to prevent and manage frailty and fragility fractures from current clinical practice guidelines. We also critically assess recently published literature in relation to exercise interventions to mitigate frailty and fragility fractures.

RECENT FINDINGS

Most guidelines presented similar recommendations that included the prescription of individually tailored, multicomponent exercise programs, discouragement of prolonged sitting and inactivity, and combining exercise with optimal nutrition. To target frailty, guidelines recommend supervised progressive resistance training (PRT). For osteoporosis and fragility fractures, exercise should include weight-bearing impact activities and PRT to target bone mineral density (BMD) at the hip and spine, and also incorporate balance and mobility training, posture exercises, and functional exercise relevant to activities of daily living to reduce falls risk. Walking as a singular intervention has limited benefits for frailty and fragility fracture prevention and management. Current evidence-based clinical practice guidelines for frailty, osteoporosis, and fracture prevention recommend a multifaceted and targeted approach to optimise muscle mass, strength, power, and functional mobility as well as BMD.

Using Raw Accelerometer Data to Predict High-Impact Mechanical Loading

The purpose of this study was to develop peak ground reaction force (pGRF) and peak loading rate (pLR) prediction equations for high-impact activities in adult subjects with a broad range of body masses, from normal weight to severe obesity. A total of 78 participants (27 males; 82.4 ± 20.6 kg) completed a series of trials involving jumps of different types and heights on force plates while wearing accelerometers at the ankle, lower back, and hip. Regression equations were developed to predict pGRF and pLR from accelerometry data. Leave-one-out cross-validation was used to calculate prediction accuracy and Bland-Altman plots. Body mass was a predictor in all models, along with peak acceleration in the pGRF models and peak acceleration rate in the pLR models. The equations to predict pGRF had a coefficient of determination (R²) of at least 0.83, and a mean absolute percentage error (MAPE) below 14.5%, while the R² for the pLR prediction equations was at least 0.87 and the highest MAPE was 24.7%. Jumping pGRF can be accurately predicted through accelerometry data, enabling the continuous assessment of mechanical loading in clinical settings. The pLR prediction equations yielded a lower accuracy when compared to the pGRF equations.

Geometry and bone mineral density determinants of femoral neck strength changes following exercise

Physical exercise induces spatially heterogeneous adaptation in bone. However, it remains unclear where the changes in BMD and geometry have the greatest impact on femoral neck strength. The aim of this study was to determine the principal BMD-and-geometry changes induced by exercise that have the greatest effect on femoral neck strength. Pre- and post-exercise 3D-DXA images of the proximal femur were collected of male participants from the LIFTMOR-M exercise intervention trial. Meshes with element-by-element correspondence were generated by morphing a template mesh to each bone to calculate changes in BMD and geometry. Finite element (FE) models predicted femoral neck strength changes under single-leg stance and sideways fall load. Partial least squares regression (PLSR) models were developed with BMD-only, geometry-only, and BMD-and-geometry changes to determine the principal modes that explained the greatest variation in neck strength changes. The PLSR models explained over 90% of the strength variation with 3 PLS components using BMD-only (R² > 0.92, RMSE < 0.06 N) and 8 PLS components with geometry-only (R² > 0.93, RMSE < 0.06 N). Changes in the superior neck and distal cortex were most important during single-leg stance while the superior neck, medial head, and lateral trochanter were most important during a sideways fall. Local changes in femoral neck and head geometry could differentiate the exercise groups from the control group. Exercise interventions may target BMD changes in the superior neck, inferior neck, and greater trochanter for improved femoral neck strength in single-leg stance and sideways fall.

Modifiable risk factors for bone health & fragility fractures

Osteoporosis is an ageing disorder characterised by poor microstructural architecture of the bone and an increase in the risk of fragility fractures, which often leads to hospitalisation and eventually a loss of mobility and independence. By 2050, it is estimated that more than 30 million people in Europe will be affected by bone diseases, and European hospitalisation alone can approximately cost up to 3.5 billion euros each year [1]. Although inherited variation in bone mineral density (BMD) is pre-determined by up to 85% [2], there is a window of opportunity to optimise BMD and reduce fracture risk through key modifiable lifestyle factors during the life course. An optimal diet rich in micronutrients, such as calcium, vitamin D, and potassium, has long been considered an important modifiable component of bone health, which is attributed to their direct roles within bone metabolism. Recently, there has been emerging evidence to suggest that protein and even an adequate intake of fruit and vegetables may also play an important role in improving BMD [3,4]. Maintaining a physically active lifestyle is not only protective from non-communicable diseases such as cardiovascular disease but it also has been shown to lessen the risk of fractures later in life, thereby making it an imperative modifiable factor for bone health, particularly as it also supports peak bone mass attainment during childhood/adolescence and can facilitate the maintenance of bone mass throughout adulthood [5]. Other key lifestyle factors that could be potentially modified to reduce the risk of osteoporosis or osteoporotic fractures later in life include smoking status, alcohol intake, and body composition [6]. Therefore, the principle aim of this review is to highlight the recent evidence pertaining to modifiable lifestyle factors that contribute to optimal bone health and the prevention of fragility fractures in later life.

Assessment of Activity Profiles in Older Adults and Lower Limb Bone Parameters: Observations from the Hertfordshire Cohort Study

As muscle strength and function decline with age the optimal high-impact physical activity (PA) required for bone remodelling is rarely achievable in older adults. This study aimed to explore the activity profiles of community-dwelling older men and women and to assess the relationship between individual PA profiles and lower limb bone parameters. Participants from the Hertfordshire Cohort Study wore triaxial accelerometers for 7 days and counts of low (0.5-1.0 g), medium (1.0-1.5 g), and high (> 1.5 g) vertical-impact activity were calculated. Two years later, participants underwent a pQCT scan of the tibia (4% and 38% sites) to obtain measures of bone mineral density and bone geometry. Linear regression was used to quantify associations between bone and PA loading profiles adjusting for age, sex, loading category, and BMI. Results are presented as β [95% confidence interval]. Bone and PA data were available for 82 participants. The mean (SD) age at follow-up was 81.4(2.7) years, 41.5% (n = 34) were women. The median low-impact PA count was 5281 (Inter-quartile range (IQR) 2516-12,977), compared with a median of only 189 (IQR 54-593) in medium, and 39 (IQR 9-105) in high-impact counts. Positive associations between high-impact PA and cortical area (mm2), polar SSI (mm3), and total area (mm2) at the 38% slice (6.21 [0.88, 11.54]; 61.94 [25.73, 98.14]; 10.09 [3.18, 16.99], respectively). No significant associations were found at distal tibia. These data suggest that maintaining high (> 1.5 g)-impact activity is difficult for older adults to achieve; however, even small amounts of high-impact PA are positively associated with selected cortical bone parameters 2 years later.

Effect of fall direction on the lower hip fracture risk in athletes with different loading histories: A finite element modeling study in multiple sideways fall configurations

Physical loading makes bones stronger through structural adaptation. Finding effective modes of exercise to improve proximal femur strength has the potential to decrease hip fracture risk. Previous proximal femur finite element (FE) modeling studies have indicated that the loading history comprising impact exercises is associated with substantially higher fracture load. However, those results were limited only to one specified fall direction. It remains thus unclear whether exercise-induced higher fracture load depends on the fall direction. To address this, using magnetic resonance images of proximal femora from 91 female athletes (mean age 24.7 years with >8 years competitive career) and their 20 non-athletic but physically active controls (mean age 23.7 years), proximal femur FE models were created in 12 different sideways fall configurations. The athletes were divided into five groups by typical loading patterns of their sports: high-impact (H-I: 9 triple- and 10 high-jumpers), odd-impact (O-I: 9 soccer and 10 squash players), high-magnitude (H-M: 17 powerlifters), repetitive-impact (R-I: 18 endurance runners), and repetitive non-impact (R-NI: 18 swimmers). Compared to the controls, the FE models showed that the H-I and R-I groups had significantly (p < 0.05) higher fracture loads, 11-17% and 22-28% respectively, in all fall directions while the O-I group had significantly 10-11% higher fracture loads in four fall directions. The H-M and R-NI groups did not show significant benefit in any direction. Also, the analyses of the minimum fall strength (MFS) among these multiple fall configurations confirmed significantly 15%, 11%, and 14% higher MFSs in these impact groups, respectively, compared to the controls. These results suggest that the lower hip fracture risk indicated by higher fracture loads in athletes engaged in high impact or repetitive impact sports is independent of fall direction whereas the lower fracture risk attributed to odd-impact exercise is more modest and specific to the fall direction. Moreover, in concordance with the literature, the present study also confirmed that the fracture risk increases if the impact is imposed on the more posterolateral aspect of the hip. The present results highlight the importance of engaging in the impact exercises to prevent hip fractures and call for retrospective studies to investigate whether specific impact exercise history in adolescence and young adulthood is also associated with lower incidence of hip fractures in later life.

Effects of testosterone and exercise training on bone microstructure of rats

Background and Aim:

Male hypogonadism results from failure to produce physiological levels of testosterone. Testosterone in men is essential in masculine development, sperm production, and adult man’s health. Osteoporosis is one of the consequences of hypogonadism. Regular physical exercise and exogenous testosterone administration are frequently used to prevent or treat this condition. This study aimed to understand the effects of lifelong exercise training and testosterone levels (isolated and together) in the main bone structure parameters.

Materials and Methods:

A total of 24 rats were used and randomly divided into four groups: Control group (CG; n=6), exercised group (EG, n=6), testosterone group (TG, n=6), and testosterone EG (TEG, n=6). A micro-computed tomography equipment was used to evaluate 15 bone parameters.

Results:

Both factors (exercise training and testosterone) seem to improve the bone resistance and microstructure, although in different bone characteristics. Testosterone influenced trabecular structure parameters, namely, connectivity density, trabecular number, and trabecular space. The exercise promoted alterations in bone structure as well, although, in most cases, in different bone structure parameters as bone mineral density and medullar mineral density.

Conclusion:

Overall, exercise and testosterone therapy seems to have a synergistic contribution to the general bone structure and resistance. Further studies are warranted, comparing different individual factors, as gender, lifestyle, or testosterone protocols, to constantly improve the medical management of hypogonadism (and osteoporosis).

Minimal-Dose Resistance Training for Improving Muscle Mass, Strength, and Function: A Narrative Review of Current Evidence and Practical Considerations

Resistance training (RT) is the only non-pharmacological intervention known to consistently improve, and therefore offset age-related declines in, skeletal muscle mass, strength, and power. RT is also associated with various health benefits that are underappreciated compared with the perceived benefits of aerobic-based exercise. For example, RT participation is associated with reduced all-cause and cancer-related mortality and reduced incidence of cardiovascular disease, hypertension, and symptoms of both anxiety and depression. Despite these benefits, participation in RT remains low, likely due to numerous factors including time constraints, a high-perceived difficulty, and limited access to facilities and equipment. Identification of RT strategies that limit barriers to participation may increase engagement in RT and subsequently improve population health outcomes. Across the lifespan, declines in strength and power occur up to eight times faster than the loss of muscle mass, and are more strongly associated with functional impairments and risks of morbidity and mortality. Strategies to maximise healthspan should therefore arguably focus more on improving or maintaining muscle strength and power than on increasing muscle mass per se. Accumulating evidence suggests that minimal doses of RT, characterised by lower session volumes than in traditional RT guidelines, together with either (1) higher training intensities/loads performed at lower frequencies (i.e. low-volume, high-load RT) or (2) lower training intensities/loads performed at higher frequencies and with minimal-to-no equipment (i.e. resistance 'exercise snacking'), can improve strength and functional ability in younger and older adults. Such minimal-dose approaches to RT have the potential to minimise various barriers to participation, and may have positive implications for the feasibility and scalability of RT. In addition, brief but frequent minimal-dose RT approaches (i.e. resistance 'exercise snacking') may provide additional benefits for interrupting sedentary behaviour patterns associated with increased cardiometabolic risk. Compared to traditional approaches, minimal-dose RT may also limit negative affective responses, such as increased discomfort and lowered enjoyment, both of which are associated with higher training volumes and may negatively influence exercise adherence. A number of practical factors, including the selection of exercises that target major muscle groups and challenge both balance and the stabilising musculature, may influence the effectiveness of minimal-dose RT on outcomes such as improved independence and quality-of-life in older adults. This narrative review aims to summarise the evidence for minimal-dose RT as a strategy for preserving muscle strength and functional ability across the lifespan, and to discuss practical models and considerations for the application of minimal-dose RT approaches.

Physical activity induced adaptation can increase proximal femur strength under loading from a fall onto the greater trochanter

Physical activity enhances proximal femur bone mass, but it remains unclear whether the benefits translate into an enhanced ability to resist fracture related loading. We recently used baseball pitchers as a within-subject controlled model to demonstrate physical activity induced proximal femur adaptation in regions associated with weight bearing and increased strength under single-leg stance loading. However, there was no measurable benefit to resisting common injurious loading (e.g. a fall onto the greater trochanter). A lack of power and a small physical activity effect size may have contributed to the latter null finding. Softball pitchers represent an alternative within-subject controlled model to explore adaptation of the proximal femur to physical activity, exhibiting greater dominant-to-nondominant (D-to-ND) leg differences than baseball pitchers. The current study used quantitative computed tomography, statistical parametric mapping, and subject-specific finite element (FE) modeling to explore adaptation of the proximal femur to physical activity in female softball pitchers (n = 25). Female cross-country runners (n = 15) were included as symmetrically loaded controls, showing very limited D-to-ND leg differences. Softball pitchers had D-to-ND leg differences in proximal femur, femoral neck, and trochanteric volumetric bone mineral density and content, and femoral neck volume. Voxel-based morphometry analyses and cortical bone mapping showed D-to-ND leg differences within a large region connecting the superior femoral head, inferior femoral neck and medial intertrochanteric region, and within the greater trochanter. FE modeling revealed pitchers had 19.4% (95%CI, 15.0 to 23.9%) and 4.9% (95%CI, 1.7 to 8.2%) D-to-ND leg differences in predicted ultimate strength under single-leg stance loading and a fall onto the greater trochanter, respectively. These data affirm the spatial and strength adaptation of the proximal femur to weight bearing directed loading and demonstrate that the changes can also have benefits, albeit smaller, on resisting loads associated with a sideways fall onto the greater trochanter.

The Efficacy of Brief School-Based Exercise Programs in Improving Pubertal Bone Mass and Physical Fitness: A Randomized Controlled Trial

PURPOSE

To examine the effects of three types of school-based exercises on bone health and physical fitness function in Chinese boys and girls.

METHODS

One hundred and seventy-four Chinese boys and girls were randomly assigned into four groups: (1) sham exercise (ShEx); (2) high-impact exercise (HiEx); (3) high-impact exercise with various directions (HiExVi); and (4) high-intensity interval exercise (HiInEx). Speed of sound (SOS) and physical fitness parameters were determined before and after six-month intervention.

RESULTS

At the end of six-month intervention, participants in all groups show an increment of SOS compared with the baseline (p < 0.05), and the changes were higher in HiEx (mean: 38.878 m/s, 95% CI: 32.885~44.872, p = 0.001) and HiExVi groups (49.317 m/s, 42.737~55.897, p < 0.001) compared with ShEx group (20.049 m/s, 13.751~26.346). Six-month exercise training generated a reduction of percent of body fat (PBF) and waist-hip ratio (WHR) (p < 0.05). The decrease of PBF was greater in HiExVi (-1.222%, -1.820~-0.624, p = 0.012) and HiInEx groups (-1.395%, -1.809~-0.982, p = 0.003), whereas the reduction of WHR was larger in HiEx (-0.026, -0.039~-0.014, p = 0.009), HiExVi (-0.024, -0.036~-0.012, p = 0.021), and HiInEx groups (-0.035, -0.046~-0.024, p < 0.001) compared with ShEx group. Balance function (BLF), vital capacity (VC), standing long jump (SLJ), and sit up (SU) increased in all intervention groups (p < 0.05). The BLF increased in HiEx (6.332 s, 4.136~8.528, p = 0.001), HiExVi (10.489 s, 8.934~12.045, p < 0.001), and HiInEx groups (9.103 s, 7.430~10.776, p < 0.001) showed a greater change than that of ShEx group (1.727 s, 0.684~2.770). The increment of VC (273.049 mL, 199.510~346.587, p < 0.001) and SU (2.537 times/min, 0.639~4.435, p = 0.017) was higher in HiInEx group, whereas the accrual in SLJ was larger in HiExVi (7.488 cm, 4.936~10.040, p = 0.007) compared with ShEx group (58.902 mL, 7.990~109.814; -0.463 times/min, -2.003~1.077; 1.488 cm, -0.654~3.630).

CONCLUSION

The brief school-based exercises were effective in improving schoolchildren's health, but they showed different effects, with HiEx mostly improving bone health, HiInEx largely benefiting physical fitness function, and HiExVi enhancing both bone and physical fitness.

Effects of exercise frequency and training volume on bone changes following a multi-component exercise intervention in middle aged and older men: Secondary analysis of an 18-month randomized controlled trial

Progressive resistance training (PRT) combined with weight-bearing impact exercise are recommended to optimize bone health, but the optimal frequency and dose of training remains uncertain. This study, which is a secondary analysis of an 18-month intervention in men aged 50-79 years, examined the association between exercise frequency and the volume of training with changes in DXA and QCT-derived femoral neck (FN) and lumbar spine (LS) bone outcomes, respectively. Men were allocated to either thrice-weekly PRT plus impact exercise training (n = 87) or a non-exercising (n = 85) group. Average weekly exercise frequency (ExFreq) and training volume per session [PRT volume (weight lifted, kg), number of weight-bearing impacts (jumps completed) and total training volume] over the 18-months were calculated from the participants' exercise cards. Regression analysis showed that average weekly ExFreq and training volume per session were positively associated with the 18-month changes in FN BMD and LS trabecular volumetric BMD. Men completing on average 1 to <2 and ≥2 sessions/week had a 1.6 to 2.2% greater net gain in FN BMD relative to non-exercising men, while those completing ≥2 sessions/week had 3.9 to 5.2% net gain in LS trabecular vBMD compared to non-exercising men and those completing <1 session/week. Further analysis showed that the average number of impact loads per session, but not the average PRT weight-lifted, was positively associated with changes in BMD. Every 10 impact loads per session over 18 months was associated with a 0.3% and 1.3% increase in FN BMD and LS trabecular vBMD, respectively. In conclusion, this study indicates that exercise frequency and training volume were predictors of the changes in hip and spine BMD following a multi-component exercise program, and that the number of impact loads rather than PRT weight lifted per session was more important for eliciting positive skeletal responses in middle-aged and older men.

Regular Strength and Sprint Training Counteracts Bone Aging: A 10-Year Follow-Up in Male Masters Athletes

Cross-sectional and interventional studies suggest that high-intensity strength and impact-type training provide a powerful osteogenic stimulus even in old age. However, longitudinal evidence on the ability of high-intensity training to attenuate age-related bone deterioration is currently lacking. This follow-up study assessed the role of continued strength and sprint training on bone aging in 40- to 85-year-old male sprinters (n = 69) with a long-term training background. Peripheral quantitative computed tomography (pQCT)-derived bone structural, strength, and densitometric parameters of the distal tibia and tibia midshaft were assessed at baseline and 10 years later. The groups of well-trained (actively competing, sprint training including strength training ≥2 times/week; n = 36) and less-trained (<2 times/week, no strength training, switched to endurance training; n = 33) athletes were formed according to self-reports at follow-up. Longitudinal changes in bone traits in the two groups were examined using linear mixed models. Over the 10-year period, group-by-time interactions were found for distal tibia total bone mineral content (BMC), trabecular volumetric bone mineral density (vBMD), and compressive strength index, and for mid-tibia cortical cross-sectional area, medullary area, total BMC, and BMC at the anterior and posterior sites (polar mass distribution analysis) (p < 0.05). These interactions reflected maintained (distal tibia) or improved (mid-tibia) bone properties in the well-trained and decreased bone properties in the less-trained athletes over the 10-year period. Depending on the bone variable, the difference in change in favor of the well-trained group ranged from 2% to 5%. The greatest differences were found in distal tibia trabecular vBMD and mid-tibia posterior BMC, which remained significant (p < 0.05) after adjustment for multiple testing. In conclusion, our longitudinal findings indicate that continued strength and sprint training is associated with maintained or even improved tibial properties in middle-aged and older male sprint athletes, suggesting that regular, intensive exercise counteracts bone aging. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Feasibility, safety and effectiveness of a pilot 16-week home-based, impact exercise intervention in postmenopausal women with low bone mineral density

The feasibility and efficacy of home-based, impact exercise are unclear. This pilot impact exercise intervention was feasible and safe, and improved bone health and physical function in postmenopausal women with low bone density. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk.

INTRODUCTION

The feasibility and efficacy of impact exercise in postmenopausal women with low bone mineral density (BMD) are unclear. We aimed to determine adherence, safety and changes in BMD, bone microarchitecture and physical function following a pilot home-based, impact exercise intervention in postmenopausal women with low BMD.

METHODS

Fifty community-dwelling postmenopausal women with BMD T-scores < - 1.0 participated in 16 weeks of home-based impact exercise progressively increasing to 50 multi-directional unilateral hops on each leg daily. Bone density and structure were assessed by lumbar spine and hip dual-energy X-ray absorptiometry (DXA), 3D modelling (3D-SHAPER) of hip DXA scans and distal tibial high-resolution peripheral quantitative computed tomography scans. Physical performance was assessed by repeated chair stand time and stair climb time.

RESULTS

Forty-four women (mean ± SD age 64.5 ± 7.5 years) completed the intervention, with adherence of 85.3 ± 17.3%. Reasons for withdrawal were related soreness (n = 2), unrelated injury (n = 1) and loss of interest (n = 3). Femoral neck areal BMD increased by 1.13 ± 3.76% (p = 0.048). Trabecular volumetric BMD (vBMD) increased at the total hip (2.27 ± 7.03%; p = 0.038) and femoral neck increased (3.20 ± 5.39%; p < 0.001). Distal tibia total vBMD increased by 0.32 ± 0.88% (p = 0.032) and cortical cross-sectional area increased by 0.55 ± 1.54% (p = 0.034). Chair stand and stair climb time improved by 2.34 ± 1.88 s (p < 0.001) and 0.27 ± 0.49 s (p < 0.001), respectively.

CONCLUSION

A 16-week home-based, impact exercise was feasible and may be effective in improving femoral neck areal BMD, total hip and distal tibial vBMD and physical function in postmenopausal women. Appropriately designed randomised controlled trials are now required to determine whether such interventions can reduce fracture risk in older populations.

High-impact exercise stimulated localised adaptation of microarchitecture across distal tibia in postmenopausal women

We provided evidence that a 6-month regular hopping exercise intervention can increase trabecular number and possibly trabecular volume fraction of the distal tibia. Our novel localised analysis demonstrated region-specific changes, predominantly in the anterior region, in postmenopausal women.

INTRODUCTION

The localisation of bone remodelling and microarchitectural adaptation to exercise loading has not been demonstrated previously in vivo in humans. The aim of this study is to assess the feasibility of using 3D image registration and high-resolution peripheral quantitative computed tomography (HR-pQCT) to investigate the effect of high-impact exercise on human trabecular bone variables and remodelling rate across the distal tibia.

METHODS

Ten postmenopausal women were recruited for 6-month unilateral hopping exercises, with HR-pQCT scans taken of both exercise leg (EL) and control leg (CL) for each participant before and after the intervention. A 3D image registration was used to ensure measurements were taken at the same region. Short-term reproducibility tests were conducted prior to the assessment using identical setup. The results were assessed comparing CL and EL, and interaction (time × leg) using a two-way repeated measures analysis of variance (RM-ANOVA).

RESULTS

Across the whole tibia, we observed significant increases in trabecular number (Tb.N) (+ 4.4%) and trabecular bone formation rate (tBFR) (3.3%), and a non-significant increase in trabecular bone volume fraction (BV/TV) (+ 1%) in the EL. Regional resorption was higher in the CL than the EL, with this difference being statistically significant at the lateral tibia. In the EL, tBFR was significantly higher in the anterior region than the medial but a trabecular bone resorption rate (tBRR) showed no significant regional variation. Conversely in the CL, both tBFR and tBRR were significantly higher in the anterior and lateral than the medial region.

CONCLUSION

We demonstrated that it was possible to detect exercise-related bone adaptation with 3D registration of HR-pQCT scan data. Regular hopping exercise increased Tb.N and possibly BV/TV across the whole distal tibia. A novel finding of the study was that tBFR and tBRR responses to loading were localised: changes were achieved by formation rate exceeding resorption rate in the exercise leg, both globally and at the anterior region where turnover was greatest.

TRIAL REGISTRATION

clinicaltrials.gov : NCT03225703.

Physical Activity and Bone Health in Men: A Systematic Review and Meta-Analysis

Background

Research on osteoporosis and physical activity often focuses on women. We aimed to conduct a systematic review to assess the benefits and harms of physical activity interventions for men’s bone health.

Methods

We used standard methods and searched for randomized controlled trials (RCTs) (duration, ≥6 months) published in all languages across multiple databases and trial registries. The last search was conducted on July 22, 2020.

Results

We included 11 studies (14 publications), resulting in a sample of N=723 men (range, 17–132 participants). We found low-certainty evidence that physical activity has little influence on the areal bone mineral density (aBMD) at the total hip (5 RCTs, N=324; mean difference [MD], 0.03 [95 confidence interval (CI), 0.01 to 0.05]) and little or no influence on the aBMD at the femoral neck (3 RCTs, N=186; MD, 0.00 [95% CI, −0.04 to 0.04]), lumbar spine (3 RCTs; N=213; MD, 0.05 [95% CI, −0.01 to 0.11]), and whole body (4 RCTs, N=203; MD, −0.00 [95% CI, −0.03 to 0.02]).

Conclusions

We found low-certainty evidence that physical activity (≥6 months) has some effect on the total hip in men, but new evidence may change this finding. This review highlights the gap in the evidence on specific intervention prescriptions that can benefit the bone geometry, structure, microarchitecture, and, ultimately, bone strength in men. Future research should engage in comprehensive reporting of harms, quality of life outcomes, advanced imaging findings, and long-term interventions.

Bone Health and Osteoporosis Prevention and Treatment

Postmenopausal osteoporosis is a common condition and is associated with increased risk of fracture, including hip and vertebral fractures that in turn can have devastating consequences on morbidity and mortality. In this article, we review the pathogenesis and diagnostic approach to postmenopausal osteoporosis. We review available nonpharmacologic and pharmacologic therapies and we discuss their clinical efficacy and complications, with a detailed discussion of atypical femur fractures and osteonecrosis of the jaw.

Effects of supervised high-intensity resistance and impact training or machine-based isometric training on regional bone geometry and strength in middle-aged and older men with low bone mass: The LIFTMOR-M semi-randomised controlled trial

INTRODUCTION

Few data exist on the effects of bone-targeted exercise on geometric and biomechanical indices of bone strength in men. The Lifting Intervention For Training Muscle and Osteoporosis Rehabilitation for Men (LIFTMOR-M) trial was designed to compare the efficacy and safety of two novel, supervised, twice-weekly, high-intensity exercise programs in middle-aged and older men with osteopenia and osteoporosis on musculoskeletal health and risk factors related to falls and fractures. The current report includes secondary outcomes of the LIFTMOR-M exercise intervention trial.

PURPOSE

Our goal was to determine the effects of two supervised, twice-weekly, high-intensity exercise programs on bone geometry and strength of the proximal femur, and distal and proximal sites of the tibia and radius in middle-aged and older men with osteopenia and osteoporosis.

METHODS

Generally-healthy men (≥45 years), with low lumbar spine (LS) and/or proximal femur areal bone mineral density (aBMD), were recruited from the community. Eligible participants were randomised to either eight months of twice-weekly supervised high-intensity progressive resistance and impact training (HiRIT) or supervised machine-based isometric axial compression (IAC) exercise training. Intervention group outcomes were compared at baseline and eight months with a matched but non-randomised control group (CON) who self-selected to usual activities. DXA scans (Medix DR, Medilink, France) of the skeletally non-dominant proximal femur were analysed using 3D hip software (DMS Group, France) to derive femoral neck (FN) and total hip (TH) bone mineral content (BMC), volume, and volumetric bone mineral density (vBMD) for total, trabecular and cortical bone compartments. Total FN cortical thickness was determined as well as anterior, posterior, lateral and medial subregions. pQCT scans (XCT-3000, Stratec, Germany) of the 4 and 38% sites of the tibia, and 4 and 66% sites of the radius were conducted to determine a range of geometric and bone structural strength indices. Intervention effects were examined using univariate ANCOVA of percent change, and repeated measures ANCOVA of raw baseline and follow-up data, controlling for initial values, using intention-to-treat and per-protocol approaches.

RESULTS

Ninety-three men (67.1 ± 7.5 yrs, 175.2 ± 6.7 cm, 82.1 ± 11.6 kg, 26.7 ± 3.5 kg/m²) with lower than average aBMD (LS T-score -0.06 ± 1.04, FN T-score -1.58 ± 0.58, TH T-score -1.00 ± 0.58) were recruited, and designated CON (n = 26) or randomised to HiRIT (n = 34) or IAC (n = 33). Compliance to the supervised exercise programs did not differ (HiRIT 77.8 ± 16.6% versus IAC 78.5 ± 14.8%, p = 0.872). HiRIT improved medial FN cortical thickness compared with CON (5.6 ± 1.7% versus -0.1 ± 1.9%, p = 0.028) and IAC (5.6 ± 1.7% versus 0.7 ± 1.7%, p = 0.044). Distal tibia total BMC, vBMD, area and bone strength index, and trabecular BMC and bone strength index all declined for CON compared with maintenance for both HiRIT and IAC (all p < 0.05). HiRIT maintained distal tibia trabecular area compared with a loss in CON (0.2 ± 0.5% versus -1.6 ± 0.5%, p = 0.013). HiRIT and IAC maintained distal radius total BMC compared with loss in CON (-0.1 ± 0.7% versus -3.7 ± 0.8%, p = 0.001; 1.3 ± 0.7% versus -3.7 ± 0.8%, p < 0.001, respectively). HiRIT and IAC maintained distal radius total bone strength index compared with loss in CON (1.4 ± 1.4% versus -6.0 ± 1.6%, p = 0.001; 0.2 ± 1.3% versus -6.0 ± 1.6%, p = 0.004, respectively). HiRIT reduced proximal radius cortical area compared with CON (-3.1 ± 1.0% versus 1.1 ± 1.2%, p = 0.011) and IAC (-3.1 ± 1.0% versus -0.2 ± 1.0%, p = 0.042). No between-group differences were detected in any pQCT-derived bone outcome at the diaphyseal tibia 38% site.

CONCLUSION

Findings indicate that supervised HiRIT provides a positive stimulus to cortical bone at the medial FN compared with supervised IAC exercise, and both HiRIT and IAC preserve bone strength at the distal tibia and distal radius. These effects may translate into a reduced risk of lower and upper extremity fracture in middle-aged and older men with low bone mass.

Postmenopausal osteoporosis is a musculoskeletal disease with a common genetic trait which responds to strength training: a translational intervention study

Background:

Clinical evidence suggests that body muscle mass is positively associated with bone mass, of significance for the elderly population at risk of osteoporosis (OP). Furthermore, muscle and bone interact mechanically and functionally, via local interactions as well as remotely via secreted components. Thus, it was of interest to compare muscle transcriptomes in postmenopausal OP and healthy women, and study effects of strength training on the muscle transcriptome, muscle stress proteins and bone mineral density (BMD).

Methods:

Skeletal muscle histological and genetic properties were compared in postmenopausal healthy (n = 18) and OP (n = 17) women before and after heavy-load strength training for 13–15 weeks. The cohorts were of similar age and body mass index without interfering diseases, medication or difference in lifestyle factors. Muscle biopsies obtained before and after intervention were studied histologically, and stress proteins and transcriptomes analyzed.

Results:

The OP women showed distinct muscle transcription profiles when compared with healthy women and had higher levels of the stress proteins HSP70 and α-β-crystalline. A set of 12 muscle transcripts, including ACSS3, FZD4, GNAI1 and IGF1, were differentially expressed before and after intervention (false discovery rate ⩽0.10, p ⩽0.001), and their corresponding bone transcripts were associated with BMD. Experimental data underline and describe the functionality of these genes in bone biology. OP women had 8% (p <0.01) higher proportion of type I fibres, but muscle fibre cross-sectional area did not differ. Muscle strength increased in both groups (p <0.01).

Conclusions:

Postmenopausal healthy and OP women have distinct muscle transcriptomes [messenger ribonucleic acids (mRNAs) and microRNAs] that are modulated by strength training, translating into key protein alterations and muscle fibre changes. The function of common skeletal muscle and bone genes in postmenopausal OP is suggestive of a shared disease trait.

Heterogeneous Spatial and Strength Adaptation of the Proximal Femur to Physical Activity: A Within-Subject Controlled Cross-Sectional Study

Physical activity (PA) enhances proximal femur bone mass, as assessed using projectional imaging techniques. However, these techniques average data over large volumes, obscuring spatially heterogeneous adaptations. The current study used quantitative computed tomography, statistical parameter mapping, and subject-specific finite element (FE) modeling to explore spatial adaptation of the proximal femur to PA. In particular, we were interested in adaptation occurring at the superior femoral neck and improving strength under loading from a fall onto the greater trochanter. High/long jump athletes (n = 16) and baseball pitchers (n = 16) were utilized as within-subject controlled models as they preferentially load their take-off leg and leg contralateral to their throwing arm, respectively. Controls (n = 15) were included but did not show any dominant-to-nondominant (D-to-ND) leg differences. Jumping athletes showed some D-to-ND leg differences but less than pitchers. Pitchers had 5.8% (95% confidence interval [CI] 3.9%-7.6%) D-to-ND leg differences in total hip volumetric bone mineral density (vBMD), with increased vBMD in the cortical compartment of the femoral neck and trochanteric cortical and trabecular compartments. Voxel-based morphometry analyses and cortical bone mapping showed pitchers had D-to-ND leg differences within the regions of the primary compressive trabeculae, inferior femoral neck, and greater trochanter but not the superior femoral neck. FE modeling revealed pitchers had 4.1% (95% CI 1.4%-6.7%) D-to-ND leg differences in ultimate strength under single-leg stance loading but no differences in ultimate strength to a fall onto the greater trochanter. These data indicate the asymmetrical loading associated with baseball pitching induces proximal femur adaptation in regions associated with weight bearing and muscle contractile forces and increases strength under single-leg stance loading. However, there were no benefits evident at the superior femoral neck and no measurable improvement in ultimate strength to common injurious loading during aging (ie, fall onto the greater trochanter), raising questions as to how to better target these variables with PA. © 2019 American Society for Bone and Mineral Research.

Effects of a 12-Month Supervised, Community-Based, Multimodal Exercise Program Followed by a 6-Month Research-to-Practice Transition on Bone Mineral Density, Trabecular Microarchitecture, and Physical Function in Older Adults: A Randomized Controlled Trial

Multicomponent exercise programs are recommended to reduce fracture risk; however, their effectiveness in real-world community settings remain uncertain. This 18-month randomized controlled trial investigated the effects of a 12-month, community-based, supervised multicomponent exercise program followed by a 6-month "research-to-practice" transition on areal bone mineral density (BMD), trabecular bone microarchitecture, functional performance, and falls in older adults at increased fracture risk. One-hundred and sixty-two adults aged ≥60 years with osteopenia or at increased falls risk were randomized to the Osteo-cise: Strong Bones for Life multicomponent exercise program (n = 81) or a control group (n = 81). Exercise consisted of progressive resistance, weight-bearing impact, and balance training (3-days/week) performed at community leisure centers. Overall 148 (91%) participants completed the trial, and mean exercise adherence was 59% after 12 months and 45% during the final 6 months. After 12 months, there were significant net beneficial effects of exercise on lumbar spine and femoral neck BMD (1.0% to 1.1%, p < 0.05), muscle strength (10% to 13%, p < 0.05), and physical function (timed stair climb 5%; four-square step test 6%; sit-to-stand 16%, p ranging <0.05 to <0.001), which persisted after the 6-month transition. There were no significant effects of the 18-month intervention on distal femur or proximal tibia trabecular bone microarchitecture or falls incidence, but per protocol analysis (≥66% exercise adherence) revealed there was a significant net benefit of exercise (mean [95% confidence interval] 2.8% [0.2, 5,4]) on proximal tibia trabecular bone volume fraction (Osteo-cise 1.5% [-1.2, 4.2]; controls -1.3% [-2.6, 0.1]) after 18 months due to changes in trabecular number (Osteo-cise 1.7% [-0.9, 4.3]; controls -1.1% [-2.4, 0.2]) but not trabecular thickness (Osteo-cise - 0.2% [-0.5, 0.2]; controls -0.2% [-0.4, 0.0]). In conclusion, this study supports the effectiveness of the Osteo-cise: Strong Bones for Life program as a real-world, pragmatic, evidence-based community exercise program to improve multiple musculoskeletal health outcomes in older adults at increased fracture risk. © 2019 American Society for Bone and Mineral Research.

A High-Intensity Exercise Intervention Improves Older Women Lumbar Spine and Distal Tibia Bone Microstructure and Function: A 20-Week Randomized Controlled Trial

Introduction: The effects of ageing on bone can be mitigated with different types of physical training, such as power training. However, stimuli that combine increasing external and internal loads concomitantly may improve bone quality. The goal of this study was to assess the efficacy of a combined power and plyometric training on lumbar spine and distal tibia microstructure and function. Methods: 38 sedentary elderly women between 60 and 70 years were randomly allocated in experimental (N = 21) and control group (N = 17). The effects of the 20-week protocol on lumbar spine microstructure and tibia microstructure and function were assessed by trabecular bone score (TBS), high resolution peripheral quantitative computed tomography (HR-pQCT) and microfinite element analysis. Results: when compared to the effects found in the control group, the experimental group showed significant improvements in lumbar spine TBS (Hedges' g = 0.77); and in distal tibia trabecular thickness (g = 0.82) and trabecular bone mineral density (g=0.63). Conclusion: our findings underscore the effectiveness of the proposed intervention, suggesting it as a new strategy to slow down and even reverse the structural and functional losses in the skeletal system due to ageing.

Adaptation of Proximal Femur to Mechanical Loading in Young Adults: Standard Vs Localized Regions Evaluated by DXA

Regions of the proximal femur with less adaptive protection by mechanical loading may be at increased risk of structural failure. Since the size and location of these regions diverge from those defined by the dual-energy X-ray absorptiometry manufacturers the purpose of this study was to compare areal bone mineral density (aBMD) of different regions of the proximal femur considering impact loads from physical activity (PA). The participants were 134 young adults divided into 2 groups according to the impact of PA performed in the last 12 mo: high-impact PA and low-impact PA. The aBMD of the proximal femur was assessed by dual-energy X-ray absorptiometry at the standard femoral neck, intertrochanter, and trochanter, and at specific locations of the superolateral femoral neck and intertrochanteric region. The bone-specific physical activity questionnaire was used to estimate the impact load of PA. Comparisons between groups were adjusted for body height and body lean mass. Interaction analysis between sex and PA groups were conducted with analysis of variance. Comparisons of aBMD between bone regions were analyzed separately for men and women with repeated measures analysis of variance. In the high-impact PA group, men benefit more than women at all bone regions, except the aBMD at intertrochanteric region. Analyses of repeated measures did not reveal any significant interaction effect between bone regions (standard vs specific) and PA groups (low vs high-impact). In conclusion, aBMD differences due to mechanical loading were more pronounced in men than in women; the magnitude of the aBMD differences as a result of different levels of PA was similar between standard and localized regions.

High-Impact Exercise Increased Femoral Neck Bone Density With No Adverse Effects on Imaging Markers of Knee Osteoarthritis in Postmenopausal Women

High-impact exercise can improve femoral neck bone mass but findings in postmenopausal women have been inconsistent and there may be concern at the effects of high-impact exercise on joint health. We investigated the effects of a high-impact exercise intervention on bone mineral density (BMD), bone mineral content (BMC), and section modulus (Z) as well as imaging biomarkers of osteoarthritis (OA) in healthy postmenopausal women. Forty-two women aged 55 to 70 years who were at least 12 months postmenopausal were recruited. The 6-month intervention consisted of progressive, unilateral, high-impact exercise incorporating multidirectional hops on one randomly assigned exercise leg (EL) for comparison with the contralateral control leg (CL). Dual-energy X-ray absorptiometry (DXA) was used to measure BMD, BMC, and Z of the femoral neck. Magnetic resonance imaging (MRI) of the knee joint was used to analyze the biochemical composition of articular cartilage using T2 relaxometry and to analyze joint pathology associated with OA using semiquantitative analysis. Thirty-five participants (61.7 ± 4.3 years) completed the intervention with a mean adherence of 76.8% ± 22.5%. Femoral neck BMD, BMC, and Z all increased in the EL (+0.81%, +0.69%, and +3.18%, respectively) compared to decreases in the CL (-0.57%, -0.71%, and -0.75%: all interaction effects p < 0.05). There was a significant increase in mean T2 relaxation times (main effect of time p = 0.011) but this did not differ between the EL and CL, indicating no global effect. Semiquantitative analysis showed high prevalence of bone marrow lesions (BML) and cartilage defects, especially in the patellofemoral joint (PFJ), with no indication that the intervention caused pathology progression. In conclusion, a high-impact exercise intervention that requires little time, cost, or specialist equipment improved femoral neck BMD with no negative effects on knee OA imaging biomarkers. Unilateral high-impact exercise is a feasible intervention to reduce hip fracture risk in healthy postmenopausal women. © 2019 American Society for Bone and Mineral Research.

Exercise Mode Specificity for Preserving Spine and Hip Bone Mineral Density in Prostate Cancer Patients

PURPOSE

Androgen deprivation therapy (ADT) in men with prostate cancer (PCa) is associated with an array of adverse effects, including reduced bone mineral density (BMD) predisposing patients to increased fracture risk. Our purpose was to examine the effects of targeted exercise modes on BMD in men with PCa undergoing ADT.

METHODS

Between 2009 and 2012, 154 PCa patients 43-90 yr old on ADT were randomized to exercise targeting the musculoskeletal system (impact loading + resistance training [ImpRes], n = 57) supervised for 12 months, cardiovascular and muscular systems (aerobic + resistance training, n = 50) supervised for 6 months followed by a 6-month home-based program, or delayed aerobic exercise (DelAer, n = 47) received exercise information for 6 months followed by 6 months of supervised aerobic exercise (stationary cycling). End points were lumbar spine, hip and whole-body BMD measured by dual-energy x-ray absorptiometry with secondary end points of lean and fat mass, appendicular skeletal muscle mass, and neuromuscular strength. ANOVA was used to compare the exercise groups with DelAer at 6 and 12 months.

RESULTS

There was a between-group difference in BMD for ImpRes and DelAer at the spine (6 months, P = 0.039; 12 months, P = 0.035) and femoral neck (6 months, P = 0.050), with decline attenuated in ImpRes (~-1.0% vs ~-2.0%). Compared with DelAer, ImpRes increased appendicular skeletal muscle at 6 months (0.3 kg, P = 0.045) and improved muscle strength at 6 and 12 months (P ≤ 0.012) by 9%-34%. A limitation was inclusion of well-functioning patients.

CONCLUSION

Combined impact loading and resistance exercise attenuates bone loss at the spine and enhances overall musculoskeletal function in PCa patients undergoing ADT.

Aging and Mechanoadaptive Responsiveness of Bone

PURPOSE OF REVIEW

Osteoporosis is an age-related disorder characterized by bone loss and increased fracture susceptibility. Whether this is due to reduced loading in less active elderly individuals or inherent modifications in bone cells is uncertain. We suppose that osteoporosis is nonetheless prima facie evidence for impaired mechanoadaptation; either capacity to accrue new bone declines, or the stimulus for such accrual is absent/can no longer be triggered in the aged. Herein, we provide only sufficient background to enable a focus on recent advances which seek to address such dilemmas.

RECENT FINDINGS

Recent advances from innovative high-impact loading regimes emphasize the priming of mechanoadaptation in the aged, such that low-to-moderate intensity loading becomes beneficial. These new findings lead us to speculate that aged bone mechanoadaptation is not driven solely by strain magnitude but is instead sensitive to high strain gradients. Impaired mechanoadaptation is a feature of the aged skeleton. Recent advances indicate that novel interventional loading regimes can restore mechanoadaptive capacity, enabling new approaches for retaining bone health in the aged. Innovative exercise paradigms appear to be capable of "hacking" into the osteogenic signal produced by exercise such that low-to-moderate intensity activities may also become more beneficial. Deciphering the underpinning mechanism(s) will also enable new pharmacological intervention for retaining bone health in the aged.

Hip Fracture Discrimination Based on Statistical Multi-parametric Modeling (SMPM)

Studies using quantitative computed tomography (QCT) and data-driven image analysis techniques have shown that trabecular and cortical volumetric bone mineral density (vBMD) can improve the hip fracture prediction of dual-energy X-ray absorptiometry areal BMD (aBMD). Here, we hypothesize that (1) QCT imaging features of shape, density and structure derived from data-driven image analysis techniques can improve the hip fracture discrimination of classification models based on mean femoral neck aBMD (Neck.aBMD), and (2) that data-driven cortical bone thickness (Ct.Th) features can improve the hip fracture discrimination of vBMD models. We tested our hypotheses using statistical multi-parametric modeling (SMPM) in a QCT study of acute hip fracture of 50 controls and 93 fragility fracture cases. SMPM was used to extract features of shape, vBMD, Ct.Th, cortical vBMD, and vBMD in a layer adjacent to the endosteal surface to develop hip fracture classification models with machine learning logistic LASSO. The performance of these classification models was evaluated in two aspects: (1) their hip fracture classification capability without Neck.aBMD, and (2) their capability to improve the hip fracture classification of the Neck.aBMD model. Assessments were done with 10-fold cross-validation, areas under the receiver operating characteristic curve (AUCs), differences of AUCs, and the integrated discrimination improvement (IDI) index. All LASSO models including SMPM-vBMD features, and the majority of models including SMPM-Ct.Th features performed significantly better than the Neck.aBMD model; and all SMPM features significantly improved the hip fracture discrimination of the Neck.aBMD model (Hypothesis 1). An interesting finding was that SMPM-features of vBMD also captured Ct.Th patterns, potentially explaining the superior classification performance of models based on SMPM-vBMD features (Hypothesis 2). Age, height and weight had a small impact on model performances, and the model of shape, vBMD and Ct.Th consistently yielded better performances than the Neck.aBMD models. Results of this study clearly support the relevance of bone density and quality on the assessment of hip fracture, and demonstrate their potential on patient and healthcare cost benefits.

Prediction of lumbar vertebral body compressive strength of overweight and obese older adults using morphed subject-specific finite-element models to evaluate the effects of weight loss

BACKGROUND

Diet and exercise can promote weight loss in older adults; however, there is potential to increase fracture risk due to loss of bone mineral density (BMD) known to accompany weight loss. Weight loss effects on measures of bone quality and strength are currently unknown.

AIMS

The purpose of this study is to develop subject-specific finite-element (FE) models of the lumbar spine and study the effect of intentional weight loss on bone strength in a pilot data set.

METHODS

Computed tomography (CT) scans of the lumbar spine of 30 overweight and obese (mean BMI = 29.7 ± 3.9 kg/m²), older adults (mean age = 65.9 ± 4.6 years) undergoing an 18-month intentional weight loss intervention were obtained at baseline and post-intervention. Measures of volumetric BMD (vBMD) and variable cortical thickness were derived from each subject CT scan. Development of the subject-specific FE models of the lumbar spine involved model morphing techniques to accelerate the development of the models. vBMD-derived material properties and cortical thickness measures were directly mapped to baseline and post-intervention models. Bone strength was estimated through simulation of a quasi-static uniaxial compression test.

RESULTS

From baseline to 18-month post-weight loss intervention, there were statistically significant decreases in estimated bone strength (6.5% decrease; p < 0.05). Adjusting for baseline bone measures and gender revealed no statistically significant correlations between weight change and change in vBMD, cortical thickness, or bone strength.

CONCLUSION

Integration of CT-based measures and FE models with conventional areal BMD can improve the understanding of the effects of intentional weight loss on bone health.

A cross-sectional study on the age-related cortical and trabecular bone changes at the femoral head in elderly female hip fracture patients

Bone is in a continuous state of remodeling whereby old bone is absorbed and new bone is formed in its place. During this process, new formations reinforce the bone in the direction of the dominant stress trajectories through a functional adaptation. In normal aging, the balance between bone resorption and formation can be shifted. How this affects the functional adaptation remains to be investigated. Furthermore, how or whether the bone continues to change beyond the age of 85 is not yet studied in detail. In this study we examined the age-related changes in the cortical and trabecular bone in old age, and assessed whether we can find evidence of the presence of functional adaptation. We measured cortical and trabecular parameters from micro-computed tomography scans of the femoral head extracted from hip fracture patients between the age of 70 and 93 years. A significant decrease in global trabecular bone mineral density (38.1%) and cortical thickness (13.0%) was seen from the 9th to the 10th decade of life. The degree of anisotropy was maintained globally as well as locally in both high and low stress regions. The local trabecular bone mineral density decreased in both high stress and low stress regions between the 9th and 10th decade of life with similar trends. This suggests that the role of functional adaptation in maintaining the bone structural integrity in old age may be limited. This study highlights the need for a controlled clinical trial examining the cause of the continued bone degradation throughout old age.

The Efficacy and Safety of Lower-Limb Plyometric Training in Older Adults: A Systematic Review

BACKGROUND

The aging process is associated with a progressive decline of neuromuscular function, increased risk of falls and fractures, impaired functional performance, and loss of independence. Plyometric training may mitigate or even reverse such age-related deterioration; however, little research on the effects of plyometric exercises has been performed in older adults.

OBJECTIVE

The objective of this systematic review was to evaluate the safety and efficacy of plyometric training in older adults.

METHODS

Papers reporting on randomized trials of plyometric training in older adults (≥ 60 years) and published up to December 2017 were sought in the PubMed, SPORTDiscus, Scopus, and EMBASE databases, and their methodological quality was assessed using the Physiotherapy Evidence Database (PEDro) scale. A narrative synthesis of the findings is presented in this systematic review.

RESULTS

Of the 2236 identified papers, 18 were included in the review, reporting on 12 different studies with a mean PEDro score of 6.0 (range 4-7). Altogether, 289 subjects (176 females and 113 males) were included in 15 intervention groups with plyometric components (n = 8-36 per group); their mean age ranged from 58.4 to 79.4 years. The plyometric training lasted from 4 weeks to 12 months. Muscular strength, bone health, body composition, postural stability, and jump and physical performance were the most often reported outcomes. No study reported increased occurrence of injuries or other adverse events related to plyometric exercises.

CONCLUSION

Plyometric training is a feasible and safe training option with potential for improving various performance, functional, and health-related outcomes in older persons.

The interactions of physical activity, exercise and genetics and their associations with bone mineral density: implications for injury risk in elite athletes

Low bone mineral density (BMD) is established as a primary predictor of osteoporotic risk and can also have substantial implications for athlete health and injury risk in the elite sporting environment. BMD is a highly multi-factorial phenotype influenced by diet, hormonal characteristics and physical activity. The interrelationships between such factors, and a strong genetic component, suggested to be around 50-85% at various anatomical sites, determine skeletal health throughout life. Genome-wide association studies and case-control designs have revealed many loci associated with variation in BMD. However, a number of the candidate genes identified at these loci have no known associated biological function or have yet to be replicated in subsequent investigations. Furthermore, few investigations have considered gene-environment interactions-in particular, whether specific genes may be sensitive to mechanical loading from physical activity and the outcome of such an interaction for BMD and potential injury risk. Therefore, this review considers the importance of physical activity on BMD, genetic associations with BMD and how subsequent investigation requires consideration of the interaction between these determinants. Future research using well-defined independent cohorts such as elite athletes, who experience much greater mechanical stress than most, to study such phenotypes, can provide a greater understanding of these factors as well as the biological underpinnings of such a physiologically "extreme" population. Subsequently, modification of training, exercise or rehabilitation programmes based on genetic characteristics could have substantial implications in both the sporting and public health domains once the fundamental research has been conducted successfully.

Circulating miR-103a-3p and miR-660-5p are associated with bone parameters in patients with controlled acromegaly

Background Biochemical control of GH/IGF-I excess in acromegaly (ACRO) is associated with persistent impairment of trabecular microstructure leading to increased risk of vertebral fractures. Circulating miRNAs modulate the activity of osteoblasts and osteoclasts, and may be potential biomarkers of osteoporosis. Aims Identify differentially expressed miRNAs in the serum of patients with controlled ACRO vs controls and correlate miRNA levels with both biochemical and structural bone parameters. Patients and methods Twenty-seven patients with controlled ACRO (11 males, 16 females; mean age, 48 ± 5 years; BMI, 28 ± 4 kg/m2) and 27 age-, gender- and BMI-matched controls were recruited. Areal BMD at lumbar spine and femur, and trabecular bone score were assessed; volumetric BMD was measured by quantitative computed tomography QCT-Pro (Mindways). Twenty miRNAs, chosen by their putative role in bone, were quantified in serum using real-time qPCR. Results In ACRO patients, miR-103a-3p and miR-191-5p were found overexpressed, whereas miR-660-5p was underexpressed (P < 0.001). miR-103a-3p levels were negatively associated with both trabecular vBMD at trochanter and serum osteoprotegerin concentrations (P < 0.05) and positively with vitamin D concentrations (P < 0.01) and total cross-sectional area of the femoral neck (P < 0.05). miR-660-5p levels were correlated with both trabecular vBMD at trochanter and OPG concentrations (P < 0.05), but were negatively associated with vitamin D levels (P < 0.05). A negative correlation between miR-103-a-3p and miR-660-5p was found in both groups (P < 0.001). Conclusions Circulating miR-103a-3p and miR-660-5p are differentially expressed in controlled ACRO patients and associated with bone structural parameters. miRNAs may be one of the mechanisms involved in the pathogenesis of bone disease and could be used as biomarkers in ACRO patients.

Effects of Resistance Exercise on Bone Health

The prevalence of chronic diseases including osteoporosis and sarcopenia increases as the population ages. Osteoporosis and sarcopenia are commonly associated with genetics, mechanical factors, and hormonal factors and primarily associated with aging. Many older populations, particularly those with frailty, are likely to have concurrent osteoporosis and sarcopenia, further increasing their risk of disease-related complications. Because bones and muscles are closely interconnected by anatomy, metabolic profile, and chemical components, a diagnosis should be considered for both sarcopenia and osteoporosis, which may be treated with optimal therapeutic interventions eliciting pleiotropic effects on both bones and muscles. Exercise training has been recommended as a promising therapeutic strategy to encounter the loss of bone and muscle mass due to osteosarcopenia. To stimulate the osteogenic effects for bone mass accretion, bone tissues must be exposed to mechanical load exceeding those experienced during daily living activities. Of the several exercise training programs, resistance exercise (RE) is known to be highly beneficial for the preservation of bone and muscle mass. This review summarizes the mechanisms of RE for the preservation of bone and muscle mass and supports the clinical evidences for the use of RE as a therapeutic option in osteosarcopenia.

Cortical Bone Mapping: Measurement and Statistical Analysis of Localised Skeletal Changes

PURPOSE OF REVIEW

Cortical bone mapping (CBM) is a technique for measuring localised skeletal changes from computed tomography (CT) images. It can provide measurements with accuracy surpassing the underlying imaging resolution. CBM can detect changes in several properties of the cortex, with no prior assumptions about the likely location of said changes. This paper summarises the theory behind CBM, discusses its strengths and limitations, and reviews some studies in which it has been applied.

RECENT FINDINGS

CBM has revealed associations between fracture risk and cortical properties in specific regions of the proximal femur which present feasible therapeutic targets. Analyses of several pharmaceutical and exercise interventions quantify effects that are distinct both in location and in the nature of the micro-architectural changes. CBM has illuminated age-related changes in the proximal femur and has recently been applied to other bones, as well as to the assessment of cartilage. The CBM processing pipeline is designed primarily for large cohort studies. Its main impact thus far has not been in the realm of clinical practice, but rather to improve our fundamental understanding of localised bone structure and changes.

Sex differences in the spatial distribution of bone in relation to incident hip fracture: Findings from the AGES-Reykjavik study

In this case-cohort study, we used data-driven computational anatomy approaches to assess within and between sex spatial differences in proximal femoral bone characteristics in relation to incident hip fracture. One hundred male and 234 female incident hip fracture cases, and 1047 randomly selected noncase subcohort participants (562 female) were chosen from the population-based AGES-Reykjavik study (mean age of 77 years). The baseline -i.e. before hip fracture- hip quantitative computed tomography scans of these subjects were analyzed using voxel-based morphometry, tensor-based morphometry, and surface-based statistical parametric mapping to assess the spatial distribution of volumetric bone mineral density (vBMD), internal structure, and cortical bone properties (thickness, vBMD and trabecular vBMD adjacent to the endosteal surface) of the proximal femur, respectively, in relation to incident hip fracture. Results showed that in both men and women: 1) the superior aspect of the femoral neck and the trochanteric region (except for cortical bone thickness) were consistently identified as being associated with incident hip fracture, and 2) differences in bone properties between noncases and incident hip fracture cases followed similar trends, were located at compatible regions, and manifested heterogeneity in the spatial distribution of their magnitude with focal regions showing larger differences. With respect to sex differences, most of the regions with a significant interaction between fracture group and sex showed: 1) differences of greater magnitude in men between noncases and incident hip fracture cases with different spatial distributions for all bone properties with the exception of cortical bone thickness, and 2) that while most of these regions showed better bone quality in male cases than in female cases, female cases showed higher vBMD in the principal compressive group and higher endotrabecular vBMD at several regions including the anterior, posterior, and lateral aspects of the proximal femur. These findings indicate the value of these image analysis techniques by providing unique information about the specific patterns of bone deterioration associated with incident hip fracture and their sex differences, highlighting the importance of looking to men and women separately in the assessment of hip fracture risk.

Low Muscle Strength and Mass Is Associated With the Accelerated Decline of Bone Microarchitecture at the Distal Radius in Older Men: the Prospective STRAMBO Study

Low muscle mass and strength are associated with poor bone microarchitecture. We studied the association of muscle mass and strength with changes in bone microarchitecture of distal radius in 821 older men during an 8-year prospective follow-up. Bone microarchitecture was assessed by high resolution peripheral quantitative computed tomography (XtremeCT-1, Scanco) at baseline, then after 4 and 8 years. Relative appendicular lean mass of the upper limbs (RALM-u.l.) was calculated as DXA-measured lean mass of upper limbs divided by (height)² . Relative grip strength was calculated as grip strength divided by height. Decrease in bone mineral content (BMC), total volumetric bone mineral density (Tt.vBMD), cortical thickness (Ct.Th), cortical area (Ct.Ar) and cortical vBMD (Ct.vBMD) accelerated with age. Trabecular area (Tb.Ar) expansion and trabecular bone deterioration accelerated with age. Men in the first RALM-u.l. quartile had more rapid loss of BMC, Tt.vBMD, Ct.Th, Ct.vBMD and Ct.Ar vs. the highest quartile. They had more rapid increase in Tb.Ar. Men in the lowest quartile of grip strength had greater decrease in BMC, Tt.vBMD, Ct.Th, Ct.vBMD, Ct.Ar, and greater increase in Tb.Ar vs. the highest quartile. In the models including ALM-u.l. and grip strength (not corrected for height), both muscle-related variables were associated with more rapid bone microarchitectural deterioration (slightly more so for grip strength). Trabecular vBMD (Tb.vBMD) and Central.Tb.vBMD increased in men having higher muscle mass and strength. Trends in trabecular number and thickness did not differ across the groups in all the analyses. Thus, in men, aging-related deterioration of bone microarchitecture was most rapid after the age of 80. Low grip strength (and slightly more weakly low RALM-u.l.) is associated with the more rapid decrease in Tt.vBMD and cortical variables, and with greater Tb.Ar expansion. In conclusion, dynapenia and sarcopenia contribute to the deterioration of bone microarchitecture in older men. © 2018 American Society for Bone and Mineral Research.

Fracture Prediction by Computed Tomography and Finite Element Analysis: Current and Future Perspectives

PURPOSE OF REVIEW

This review critiques the ability of CT-based methods to predict incident hip and vertebral fractures.

RECENT FINDINGS

CT-based techniques with concurrent calibration all show strong associations with incident hip and vertebral fracture, predicting hip and vertebral fractures as well as, and sometimes better than, dual-energy X-ray absorptiometry areal biomass density (DXA aBMD). There is growing evidence for use of routine CT scans for bone health assessment. CT-based techniques provide a robust approach for osteoporosis diagnosis and fracture prediction. It remains to be seen if further technical advances will improve fracture prediction compared to DXA aBMD. Future work should include more standardization in CT analyses, establishment of treatment intervention thresholds, and more studies to determine whether routine CT scans can be efficiently used to expand the number of individuals who undergo evaluation for fracture risk.

A new quantitative 3D approach to imaging of structural joint disease

Imaging of joints with 2D radiography has not been able to detect therapeutic success in research trials while 3D imaging, used regularly in the clinic, has not been approved for this purpose. We present a new 3D approach to this challenge called joint space mapping (JSM) that measures joint space width in 3D from standard clinical computed tomography (CT) data, demonstrating its analysis steps, technical validation, and reproducibility. Using high resolution peripheral quantitative CT as gold standard, we show a marginal over-estimation in accuracy of +0.13 mm and precision of ±0.32 mm. Inter-operator reproducibility bias was near-zero at −0.03 mm with limits of agreement ±0.29 mm and a root mean square coefficient of variation 7.5%. In a technical advance, we present results from across the hip joint in 3D with optimum validation and reproducibility metrics shown at inner joint regions. We also show JSM versatility using different imaging data sets and discuss potential applications. This 3D mapping approach provides information with greater sensitivity than reported for current radiographic methods that could result in improved patient stratification and treatment monitoring.

The relationship between objectively assessed physical activity and bone health in older adults differs by sex and is mediated by lean mass

Relationships between objectively assessed free-living physical activity (PA) and changes in bone health over time are poorly understood in older adults. This study suggests these relationships are sex-specific and that body composition may influence the mechanical loading benefits of PA.

INTRODUCTION

To investigate associations of objectively assessed PA and bone health in community-dwelling older adults.

METHODS

This secondary analysis of a subset of the Tasmanian Older Adult Cohort study included participants with PA assessed utilising ActiGraph GT1M accelerometers over 7 days (N = 209 participants, 53% female; mean ± SD age 64.5 ± 7.2 years). Steps/day and PA intensity were estimated via established thresholds. Bone mineral content (BMC) was acquired at the total hip, lumbar spine, legs and whole body by DXA at baseline and approximately 2.2 years later. Relationships between PA and BMC were assessed by multivariable linear regression analyses adjusted for age, smoking status, height and total lean mass.

RESULTS

Men with above-median total hip BMC completed significantly less steps per day, but there was no significant difference in PA intensity compared with those with below-median BMC. There were no significant differences in PA in women stratified by median BMC. In women, steps/day were positively associated with leg BMC (B = 0.178; P = 0.017), and sedentary behaviour was negatively associated with leg BMC (- 0.165; 0.016) at baseline. After adjustment for confounders including lean mass and height, higher sedentary behaviour at baseline was associated with declines in femoral neck BMC (- 0.286; 0.011) but also with increases in pelvic BMC (0.246; 0.030) in men and increases in total hip BMC (0.215; 0.032) in women, over 2.2 years. No other significant longitudinal associations were observed after adjustment for body composition.

CONCLUSIONS

Associations of accelerometer-determined sedentary behaviour and PA with bone health in older adults differ by sex and anatomical site and are mediated by body composition.

Development of Subject-Specific Proximal Femur Finite Element Models Of Older Adults with Obesity to Evaluate the Effects of Weight Loss on Bone Strength

Study background

Recommendation of intentional weight loss in older adults remains controversial, due in part to the loss of bone mineral density (BMD) known to accompany weight loss. While finite element (FE) models have been used to assess bone strength, these methods have not been used to study the effects of weight loss. The purpose of this study is to develop subject-specific FE models of the proximal femur and study the effect of intentional weight loss on bone strength.

Methods

Computed tomography (CT) scans of the proximal femur of 25 overweight and obese (mean BMI=29.7 ± 4.0 kg/m²), older adults (mean age=65.6 ± 4.1 years) undergoing an 18-month intentional weight loss intervention were obtained at baseline and post-intervention. Measures of volumetric BMD (vBMD) and variable cortical thickness were derived from each subject CT scan and directly mapped to baseline and post-intervention models. Subject-specific FE models were developed using morphing techniques. Bone strength was estimated through simulation of a single-limb stance and sideways fall configuration.

Results

After weight loss intervention, there were significant decreases from baseline to 18 months in vBMD (total hip: -0.024 ± 0.013 g/cm³; femoral neck: -0.012 ± 0.014 g/cm³), cortical thickness (total hip: -0.044 ± 0.032 mm; femoral neck: -0.026 ± 0.039 mm), and estimated strength (stance: -0.15 ± 0.12 kN; fall: -0.04 ± 0.06 kN). Adjusting for baseline bone measures, body mass, and gender, correlations were found between weight change and change in total hip and femoral neck cortical thickness (all p<0.05). For every 1 kilogram of body mass lost cortical thickness in the total hip and femoral neck decreased by 0.003 mm and 0.004 mm, respectively. No significant correlations were present for the vBMD or strength data.

Conclusion

The developed subject-specific FE models could be used to better understand the effects of intentional weight loss on bone health.

Ranking of osteogenic potential of physical exercises in postmenopausal women based on femoral neck strains

The current study aimed to assess the potential of different exercises triggering an osteogenic response at the femoral neck in a group of postmenopausal women. The osteogenic potential was determined by ranking the peak hip contact forces (HCFs) and consequent peak tensile and compressive strains at the superior and inferior part of the femoral neck during activities such as (fast) walking, running and resistance training exercises. Results indicate that fast walking (5-6 km/h) running and hopping induced significantly higher strains at the femoral neck than walking at 4 km/h which is considered a baseline exercise for bone preservation. Exercises with a high fracture risk such as hopping, need to be considered carefully especially in a frail elderly population and may therefore not be suitable as a training exercise. Since superior femoral neck frailness is related to elevated hip fracture risk, exercises such as fast walking (above 5 km/h) and running can be highly recommended to stimulate this particular area. Our results suggest that a training program including fast walking (above 5 km/h) and running exercises may increase or preserve the bone mineral density (BMD) at the femoral neck.