History of amenorrhoea compromises some of the exercise-induced benefits in cortical and trabecular bone in the peripheral and axial skeleton : a study in retired elite gymnasts

Background : Female gymnasts frequently present with overt signs of hypoestrogenism, such as late menarche or menstrual dysfunction. The objective was to investigate the impact of history of amenorrhoea on the exercise-induced skeletal benefits in bone geometry and volumetric density in retired elite gymnasts.
Subjects and methods

24 retired artistic gymnasts, aged 17–36 years, who had been training for at least 15 h/week at the peak of their career and had been retired for 3–18 years were recruited. They had not been engaged in more than 2 h/week of regular physical activity since retirement. Former gymnasts who reported history of amenorrhoea (‘AME’, n = 12: either primary or secondary amenorrhoea) were compared with former gymnasts (‘NO-AME’, n = 12) and controls (‘C’, n = 26) who did not report history of amenorrhoea. Bone mineral content (BMC), total bone area (ToA) and total volumetric density (ToD) were measured by pQCT at the radius and tibia (4% and 66%). Trabecular volumetric density (TrD) and bone strength index (BSI) were measured at the 4% sites. Cortical area (CoA), cortical thickness (CoTh), medullary area (MedA), cortical volumetric density (CoD), stress–strain index (SSI) and muscle and fat area were measured at the 66% sites. Spinal BMC, areal BMD and bone mineral apparent density (BMAD) were measured by DXA.
Results

Menarcheal age was delayed in AME when compared to NO-AME (16.4 ± 0.5 years vs. 13.3 ± 0.4 years, p < 0.001). No differences were detected between AME and C for height-adjusted spinal BMC, aBMD and BMAD, TrD and BSI at the distal radius and tibia, CoA at the proximal radius, whereas these parameters were greater in NO-AME than C (p < 0.05–0.005). AME had lower TrD and BSI at the distal radius, and lower spinal BMAD than NO-AME (p < 0.05) but they had greater ToA at the distal radius (p < 0.05).
Conclusion

Greater spinal BMC, aBMD and BMAD as well as trabecular volumetric density and bone strength in the peripheral skeleton were found in former gymnasts without a history of menstrual dysfunction but not in those who reported either primary or secondary amenorrhoea. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training.

Effects of long-term tennis playing on the muscle-bone relationship in the dominant and non-dominant forearms

The relationship between muscle strength and bone mineral density illustrates the positive effect of mechanical loading on bone. But local and systemic factors may affect both muscle and bone tissues. This study investigated the effects of long-term tennis playing on the relationship between lean tissue mass and bone mineral content in the forearms, taking the body dimensions into account. Fifty-two tennis players (age 24.2 +/- 5.8 yrs, 16.2 +/- 6.1 yrs of practice) were recruited. Lean tissue mass (LTM), bone area, bone mineral content (BMC), and bone mineral density were measured at the forearms from a DXA whole-body scan. Grip strength was assessed with a dynamometer. A marked side-to-side difference (p < 0.0001) was found in favor of the dominant forearm in all parameters. Bone area and BMC correlated with grip strength on both sides (r = 0.81 - 0.84, p < 0.0001). The correlations were still significant after adjusting for whole-body BMC body height, or forearm length. This result reinforced the putative role of the muscles in the mechanical loading on bones. In addition, forearm BMC adjusted to LTM or grip strength was higher on the dominant side, suggesting that tennis playing exerts a direct effect on bone.

Bone geometry in response to long-term tennis playing and its relationship with muscle volume : a quantitative magnetic resonance imaging study in tennis players

The benefit of impact-loading activity for bone strength depends on whether the additional bone mineral content (BMC) accrued at loaded sites is due to an increased bone size, volumetric bone mineral density (vBMD) or both. Using magnetic resonance imaging (MRI) and dual energy X-ray absorptiometry (DXA), the aim of this study was to characterize the geometric changes of the dominant radius in response to long-term tennis playing and to assess the influence of muscle forces on bone tissue by investigating the muscle–bone relationship. Twenty tennis players (10 men and 10 women, mean age: 23.1 ± 4.7 years, with 14.3 ± 3.4 years of playing) were recruited. The total bone volume, cortical volume, sub-cortical volume and muscle volume were measured at both distal radii by MRI. BMC was assessed by DXA and was divided by the total bone volume to derive vBMD. Grip strength was evaluated with a dynamometer. Significant side-to-side differences (P < 0.0001) were found in muscle volume (+9.7%), grip strength (+13.3%), BMC (+13.5%), total bone volume (+10.3%) and sub-cortical volume (+20.6%), but not in cortical volume (+2.6%, ns). The asymmetry in total bone volume explained 75% of the variance in BMC asymmetry (P < 0.0001). vBMD was slightly higher on the dominant side (+3.3%, P < 0.05). Grip strength and muscle volume correlated with all bone variables (except vBMD) on both sides (r = 0.48–0.86, P < 0.05–0.0001) but the asymmetries in muscle parameters did not correlate with those in bone parameters. After adjustment for muscle volume or grip strength, BMC was still greater on the dominant side. This study showed that the greater BMC induced by long-term tennis playing at the dominant radius was associated to a marked increase in bone size and a slight improvement in volumetric BMD, thereby improving bone strength. In addition to the muscle contractions, other mechanical stimuli seemed to exert a direct effect on bone tissue, contributing to the specific bone response to tennis playing.

Short-term and long-term site-specific effects of tennis playing on trabecular and cortical bone at the distal radius

Mechanical loading during growth magnifies the normal increase in bone diameter occurring in long bone shafts, but the response to loading in long bone ends remains unclear. The aim of the study was to investigate the effects of tennis playing during growth at the distal radius, comparing the bone response at trabecular and cortical skeletal sites. The influence of training duration was examined by studying bone response in short-term (children) and long-term (young adults) perspectives. Bone area, bone mineral content (BMC), and bone mineral density (BMD) of the radius were measured by DXA in 28 young (11.6 ± 1.4 years old) and 47 adult tennis players (22.3 ± 2.7 years old), and 70 age-matched controls (12 children, 58 adults) at three sites: the ultradistal region (trabecular), the mid-distal region, and the third-distal region (cortical). At the ultradistal radius, young and adult tennis players displayed similar side-to-side differences, the asymmetry in BMC reaching 16.3% and 13.8%, respectively (P < 0.0001). At the mid- and third-distal radius, the asymmetry was much greater in adults than in children (P < 0.0001) for all the bone parameters (mid-distal radius, +6.6% versus +15.6%; third-distal radius, +6.9% versus +13.3%, for BMC). Epiphyseal bone enduring longitudinal growth showed a great capacity to respond to mechanical loading in children. Prolonging tennis playing into adulthood was associated with further increase in bone mineralization at diaphyseal skeletal sites. These findings illustrate the benefits of practicing impact-loading sports during growth and maintaining physical activity into adulthood to enhance bone mass accrual and prevent fractures later in life.

Use of calcium, folate and vitamin D3-fortified milk for 6 months improves nutritional status but not bone mass or turnover, in a group of Australia aged care

In residential care, inadequate calcium and folate intakes and low serum vitamin D (25(OH)D) concentrations are common. We assessed whether daily provision of calcium, folate, and vitamin D3-fortified milk for 6 months improved nutritional status (serum micronutrients), bone quality (heel ultrasound), bone turnover markers (parathyroid hormone, C-terminal collagen I telopeptide, terminal propeptide of type I procollagen), and/or muscle strength and mobility in a group of Australian aged care residents. One hundred and seven residents completed the study (mean (SD) age: 79.9 (10.1) years; body weight: 68.4 (15.4) kg). The median (inter-quartile range) volume of fortified milk consumed was 160 (149) ml/day. At the end of the study, the median daily vitamin D intake increased to 10.4 (8.7) μg (P < .001), which is 70% of the adequate intake (15 μg); and calcium density (mg/MJ) was higher over the study period compared with baseline (161 ± 5 mg/MJ vs. 142 ± 4 mg/MJ, P < .001). Serum 25(OH)D concentrations increased by 23 ± 2 nmol/L (83 (107)%, P < .001), yet remained in the insufficient range (mean 45 ± 2 nmol/L). Consumption of greater than the median intake of milk (160 ml/day) (n = 54, 50%) increased serum 25(OH)D levels into the adequate range (53 ± 2 nmol/L) and reduced serum parathyroid hormone by 24% (P = .045). There was no effect on bone quality, bone turnover markers, muscle strength, or mobility. Consumption of fortified milk increased dietary vitamin D intake and raised serum 25(OH)D concentrations, but not to the level thought to reduce fracture risk. If calcium-fortified milk also was used in cooking and milk drinks, this approach could allow residents to achieve a dietary calcium intake close to recommended levels. A vitamin D supplement would be recommended to ensure adequate vitamin D status for all residents.

The effects of repetitive loading on bone mass and geometry in young male tennis players : a quantative study using magnetic resonance imaging

Pre- and early puberty seem to be the most opportune times for exercise to  improve bone strength in girls, but few studies have addressed this issue in boys. This study investigated the site-, surface-, and maturity-specific exercise-induced changes in bone mass and geometry in young boys. The osteogenic effects of loading were analyzed by comparing the playing and nonplaying humeri of 43 male pre-, peri-, and postpubertal competitive tennis players 10-19 yr of age. Total bone area, medullary area, and cortical area were determined at the mid (40-50%) and distal humerus (60-70%) of both arms using MRI. Humeral bone mass (BMC) was derived from a whole body DXA scan. In prepubertal boys, BMC was 17% greater in the playing compared with nonplaying arm (p < 0.001), which was accompanied by a 12-21% greater cortical area, because of greater periosteal expansion than medullary expansion at the midhumerus and periosteal expansion associated with medullary contraction at the distal humerus. Compared with prepuberty, the side-to-side differences in BMC (27%) and cortical area (20-33%) were greater in peripuberty (p < 0.01). No differences were found between peri- and postpuberty despite longer playing history in the postpubertal players.The osteogenic response to loading was greater in peri- compared with prepubertal boys, which is in contrast with our previous findings in girls and may be caused by differences in training history. This suggests that the window of opportunity to improve bone mass and size through exercise may be longer in boys than in girls.

Depression and bone mineral density in a community sample of perimenopausal women: Geelong Osteoporosis Study

Objective: Reduced bone mineral density (BMD) in women with a history of depressive disorders has been shown in some, but not all studies. This study investigated the association between self-reported depression and BMD in an age-stratified community sample of perimenopausal women residing in the South-Eastern region of Australia.

Design: Symptoms of depression in the year between July 2000 and July 2001 were ascertained by a self-report questionnaire based on Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria. Women in the perimenopausal group who had undergone a BMD total hip and spine assessment within the 12-month period after the depression assessment were included in the analysis, resulting in a sample of 78 women aged 45 to 60 years.

Results: In this sample, 14 women were identified as depressed. There was no difference in age, hormone therapy (HT) use, or unadjusted BMD at the total hip or spine between the depressed and nondepressed women (P = 0.14, 0.89, 0.57, and 0.70, respectively), but the depressed women tended to be heavier [depressed (median weight, interquartile range = 80 kg, 66-94) vs nondepressed (72 kg, 61-80) P = 0.06]. Whereas there was no significant difference in age-, HT-, and weight-adjusted BMD at the spine [depressed (mean ± SE = 1.21 ± 0.05) vs nondepressed (1.28 ± 0.03 g/cm2) P = 0.18], adjusted BMD at the total hip for the depressed women was 7.8% lower than for the nondepressed [depressed (mean ± SE = 0.957 ± 0.038) vs nondepressed (1.038 ± 0.023 g/cm2) P = 0.04].

Conclusions: These results suggest that in perimenopausal women, self-reported depression is associated with lower BMD at the hip.

Depression and bone mineral density in a community sample of men : Geelong Osteoporosis Study

Background : Previous research in psychiatric and community samples has demonstrated reduced bone mineral density (BMD) in individuals with both clinical depression and depressive symptoms, although the findings are equivocal. This study aimed to investigate the association between self-reported depression and BMD in a community sample of men aged 20–96 years enrolled in the Geelong Osteoporosis Study.

Methods : A self-report questionnaire based on DSM-IV criteria was used to determine lifetime prevalence rates of depression within the study sample at baseline. Those currently taking oral glucocorticoids, testosterone or bisphosphonates were excluded from the analysis (n = 23) resulting in a sample of 1279 men.

Results : In this sample, 155 men reported a lifetime history of depression (LHX). There were no differences in age, weight, height, calcium intake, smoking rates or unadjusted BMD at the femoral neck between the cases and the controls, whereas unadjusted BMD at the spine was significantly lower in those with a LHX (1.254 ± 0.187 vs 1.293 ± 0.194 g/cm2). BMD adjusted for age, weight, calcium intake and smoking was 3.6% lower at the spine (1.255 ± 0.016 vs 1.295 ± 0.006 g/cm2) and 3.4% lower at the femoral neck (0.973 ± 0.011 vs 1.007 ± 0.004 g/cm2) in those with a LHX compared to controls.

Conclusion : These data are consistent with previous findings of diminished BMD in people with depressive disorders and symptoms and suggest that depression may be a risk factor for reduced BMD in community-dwelling adult men.

Bone mineral density and incidence of hip fracture in Swedish urban and rural women 1987–2002

Background and purpose Although the incidence of hip fracture during the past 50 years has increased, a break in this trend has been reported in the last decade. Whether this change is attributable to changes in bone mineral density (BMD) or whether it varies between urban and rural regions is unknown.

Methods We evaluated changes in annual hip fracture incidence in women aged ≥ 50 years in one urban population (n = 51,757) and one rural population (n = 26,446) from 1987 to 2002. We also examined secular differences in BMD (mg/cm2), evaluated by single-photon absorptiometry at the distal radius, prevalence of osteoporosis, and several other risk factors for hip fracture in one population-based sample of urban women and one sample of rural women aged 50–80 years at two time points: 1988/89 (n = 257 and n = 180, respectively) and 1998/99 (n = 171 and n = 118, respectively).

Results No statistically significant changes were evident in annual age-adjusted hip fracture incidence per 104 when analyzing all women (–0.01 per year (95% CI: –0.37, 0.35)), rural women (–0.38 per year (-1.05, 0.28)), or urban women (0.19 per year (–0.28, 0.67)). BMD (expressed as T-score) was similar in 1988/99 and 1998/99 when analyzing all women (–0.09 (–0.26, 0.09)), urban women (–0.04 (–0.27, 0.19)), or rural women (–0.15 (–0.42, 0.13)) women.

Interpretation Since no changes in age-adjusted hip fracture incidence and no differences in BMD were found during the study period, changes evident in the other risk factors for hip fracture that we investigated (such as gait velocity and balance) are either of minor importance or are counteracted by changes in other risk factors.

Exercise loading and cortical bone distribution at the tibial shaft

Cortical bone is not a uniform tissue, and its apparent density [cortical volumetric density (vBMD)] varies around the bone cross-section as well as along the axial length of the bone. It is not yet known, whether the varying vBMD distribution is attributable to modulation in the predominant loads affecting bone. The aim of the present study was to compare the cortical bone mass distribution through the bone cortex (radial distribution) and around the center of mass (polar distribution) among 221 premenopausal women aged 17–40 years representing athletes involved in high impact, odd impact, high magnitude, repetitive low impact, repetitive non-impact sports and leisure time physical activity (referent controls). Bone cross-sections at the tibial mid-diaphysis were assessed with pQCT. Radial and polar vBMD distributions were analyzed in three concentric cortical divisions within the cortical envelope and in four cortical sectors originating from the center of the bone cross-section. MANCOVA, including age as a covariate, revealed no significant group by division/sector interaction in either radial or polar distribution, but the mean vBMD values differed between groups (P < 0.001). The high and odd-impact groups had 1.2 to 2.6% (P < 0.05) lower cortical vBMD than referents, in all analyzed sectors/divisions. The repetitive, low-impact group had 0.4 to 1.0% lower (P < 0.05) vBMD at the mid and outer cortical regions and at the anterior sector of the tibia. The high magnitude group had 1.2% lower BMD at the lateral sector (P < 0.05). The present results generate a hypothesis that the radial and polar cortical bone vBMD distributions within the tibial mid-shaft are not modulated by exercise loading but the mean vBMD level is slightly affected.

Targeted exercise against osteoporosis : a systematic review and meta-analysis for optimising bone strength throughout life

Background
Exercise is widely recommended to reduce osteoporosis, falls and related fragility fractures, but its effect on whole bone strength has remained inconclusive. The primary purpose of this systematic review and meta-analysis was to evaluate the effects of long-term supervised exercise (≥6 months) on estimates of lower-extremity bone strength from childhood to older age.

Methods
We searched four databases (PubMed, Sport Discus, Physical Education Index, and Embase) up to October 2009 and included 10 randomised controlled trials (RCTs) that assessed the effects of exercise training on whole bone strength. We analysed the results by age groups (childhood, adolescence, and young and older adulthood) and compared the changes to habitually active or sedentary controls. To calculate standardized mean differences (SMD; effect size), we used the follow-up values of bone strength measures adjusted for baseline bone values. An inverse variance-weighted random-effects model was used to pool the results across studies.

Results
Our quality analysis revealed that exercise regimens were heterogeneous; some trials were short in duration and small in sample size, and the weekly training doses varied considerably between trials. We found a small and significant exercise effect among pre- and early pubertal boys [SMD, effect size, 0.17 (95% CI, 0.02-0.32)], but not among pubertal girls [-0.01 (-0.18 to 0.17)], adolescent boys [0.10 (-0.75 to 0.95)], adolescent girls [0.21 (-0.53 to 0.97)], premenopausal women [0.00 (-0.43 to 0.44)] or postmenopausal women [0.00 (-0.15 to 0.15)]. Evidence based on per-protocol analyses of individual trials in children and adolescents indicated that programmes incorporating regular weight-bearing exercise can result in 1% to8% improvements in bone strength at the loaded skeletal sites. In premenopausal women with high exercise compliance, improvements ranging from 0.5% to 2.5% have been reported.

Conclusions
The findings from our meta-analysis of RCTs indicate that exercise can significantly enhance bone strength at loaded sites in children but not in adults. Since few RCTs were conducted to investigate exercise effects on bone strength, there is still a need for further well-designed, long-term RCTs with adequate sample sizes to quantify the effects of exercise on whole bone strength and its structural determinants throughout life.

Three-month bilateral hopping intervention is ineffective in initiating bone biomarker response in healthy elderly men.

In animal studies, bone adaptation has been initiated successfully without the transient force spike associated with high impact exercises. Consequently, a 12-week bilateral hopping on the balls of the feet intervention was conducted. 25 elderly men (age 72(SD4) years, height 171(6) cm, weight 75(9) kg) were randomly assigned into exercise and control groups. Ten subjects in each group completed the study. Carboxyterminal propeptide of type I collagen (CICP), bone-specific alkaline phosphatase (bALP) and carboxyterminal telopeptide of type I collagen (CTx) were measured from venous blood samples at baseline, at 2 weeks and at the end of the intervention. Maximal ground reaction force (GRF), osteogenic index (OI) and jump height (JH) were determined from bilateral hopping test and balance was assessed with velocity of center of pressure (COPvelocity) while standing on the preferred leg with eyes open. The intervention consisted of 5–7 sets of 10 s timed bilateral hopping exercise at 75–90% intensity three times/week. There was no significant group 9 time interaction for GRF, OI and JH (P = 0.065). GRF (11% change from baseline vs. 4%), OI (15 vs. 6%) and COPvelocity (-10 vs. -1%) were not influenced by the intervention (P[0.170), while the control group improved JH (P = 0.031) (2 vs. 18%). For the biomarkers, no effect was observed in MANOVA (P = 0.536) or in univariate analyses (P = 0.082 to P = 0.820) (CICP -2 vs. -3%, CTx 8 vs. -12%, bALP 0 vs. -3.7%). Allowing transient impact force spikes may be necessary to initiate a bone response in elderly men as the intervention was ineffective.

Seventy-year-old habitual volleyball players have larger tibial cross-sectional area and may be differentiated from their age-matched peers by the osteogenic index in dynamic performance

The osteogenicity of a given exercise may be estimated by calculating an osteogenic index (OI) consisting of magnitude and rate of strain. Volleyball involves repetitive jumping and requires high power output and thus may be expected to be beneficial to bone and performance. The purpose of the present study was to examine if habitual volleyball playing is reflected in OI. Ten elderly habitual volleyball players [age 69.9 (SD 4.4) years] and ten matched controls volunteered [age 69.7 (4.2) years] as subjects. Distal tibia (d), tibial mid-shaft (50) and femoral neck (F) bone characteristics were measured using pQCT and DXA. To estimate skeletal rigidity, cross-sectional area (ToA50), and compressive (BSId) and bending strength indices (SSImax50) were calculated. Maximal performance was assessed with eccentric ankle plantar flexion, isometric leg press and countermovement jump (CMJ). A fast Fourier transform (FFT) was calculated from the acceleration of the center of mass during the CMJ. Maximal acceleration (MAG) and mean magnitude frequency (MMF) were selected to represent the constituents of OI. OI was calculated as the sum of the products of magnitudes and corresponding frequencies. Volleyball players had 7% larger ToA50 and 37% higher power in CMJ, 15% higher MAG and 36% higher OI (P B 0.047) than the matched controls. No difference was observed in leg press, plantar flexion or the MMF (P C 0.646). In conclusion, habitual volleyball players may be differentiated from their matched peers by their dynamic jumping performance, and the differences are reflected in the magnitude but not rate of loading.

An open source approach for regional cortical bone mineral density analysis

Objective: Cortical porosity, particularly at the endocortical region, is recognised to play a central role in the pathogenesis of bone fragility. Therefore, the purpose of this study was to: 1) demonstrate how cortical volumetric BMD (vBMD) distribution can be analysed from (p)QCT images and 2) highlight the clinical significance of assessing regional density distribution of cortical bone. 

Methods: We used pQCT to compare mid-tibial cortical volumetric BMD distribution of 20 young (age 24(SD2) years, mass 77(11) kg, height 178(6) cm) and 25 elderly (72(4) years, 75(9) kg, 172(5) cm) men. Radial and polar cortical vBMD distributions were analysed using a custom built open source analysis tool which allowed the cortex to be divided into three concentric cortical divisions and in 36 cortical sectors originating from the centroid of the bone.

Results: Mean vBMD did not differ between the groups (1135(16) vs. 1130(28) mg/cm, P=0.696). In contrast, there was a significant age-group by radial division interaction for radial cortical vBMD (P<0.001).

Conclusions: The proposed analysis method for analysing cortical bone density distribution of pQCT images was effective for detecting regional differences in cortical density between young and elderly men, which would have been missed by just looking at mean vBMD values.

Socioeconomic status and bone mineral density in a population-based sample of men

Overall, socioeconomic status (SES) is inversely associated with poorer health outcomes. However, current literature provides conflicting data of the relationship between SES and bone mineral density (BMD) in men. In an age-stratified population-based randomly selected cross-sectional study of men (n = 1467) we assessed the association between SES and lifestyle exposures in relation to BMD. SES was determined by matching the residential address for each subject with Australian Bureau of Statistics 2006 census data for the study region. BMD was measured at the spine and femoral neck by dual energy X-ray absorptiometry. Lifestyle variables were collected by self-report. Regression models were age-stratified into younger and older groups and adjusted for age, weight, dietary calcium, physical activity, and medications known to affect bone. Subjects with spinal abnormalities were excluded from analyses of BMD at the spine. In younger men, BMD was highest at the spine in the mid quintiles of SES, where differences were observed compared to quintile 1 (1–7%, p < 0.05). In older men, the pattern of BMD across SES quintiles was reversed, and subjects from mid quintiles had the lowest BMD, with differences observed compared to quintile 5 (1–7%, p < 0.05). Differences in BMD at the spine across SES quintiles represent a potential 1.5-fold increase in fracture risk for those with the lowest BMD. There were no differences in BMD at the femoral neck. Further research is warranted which examines the mechanisms that may underpin differences in BMD across SES quintiles and to address the current paucity of data in this field of enquiry.