Exercise and Bone Mass in Adults

Bone Mineral Density in Adolescent Boys: Cross-Sectional Observational Study

Physical inactivity of children can be a precursor of reduced bone mineral density, considered to be a typical problem only in old age. The aim of this study was to evaluate bone mineral density in 96 Polish boys aged 14–17 years with varied physical activity (swimmers, track and field athletes, non-athletes) and the effect of bone composition, birth weight and breastfeeding during infancy on bone parameters. Anthropometric and body composition measurements were performed according to the kinanthropometric standards. Bone parameters of the forearm were measured by means of dual-energy X-ray absorptiometry. Data on the infant’s birth weight and the length of breastfeeding were collected during direct interviews with mothers. The strongest links with bone parameters were found for the type of physical activity and birth weight. Regardless of birth weight, track and field athletes had the most advantageous bone parameters (mainly sT-score prox values). Swimmers with normal or low birth weight had less favourable sT-score prox values than non-athletes. The type of physical activity proved to be an important determinant of bone parameters. Childhood and adolescence are important periods of bone development and increasing the content of bone mineral components, and the bone status in later years of life depends to a large extent on this period. The perinatal period, especially the correct birth weight of the child, not only has a significant effect on general health, but also on bone status.

Bone Mineral Density in Antiretroviral Therapy-Naïve HIV-1-Infected Young Adult -Women Using Depot Medroxyprogesterone Acetate or Nonhormonal Contraceptives in Uganda

Most studies evaluating BMD in human immunodeficiency virus (HIV)‐infected populations have focused on antiretroviral therapy (ART)‐experienced patients. In this study, the association between HIV‐1 and/or depot medroxyprogesterone acetate (DMPA) and BMD among untreated HIV‐1–infected women in a resource‐limited setting was assessed before long‐term exposure to ART. The data were then compared with that of the 2005–2008 United States National Health and Nutrition Examination Survey data for non‐Hispanic White and Black women. Women aged 18–35 years, recruited from health facilities in Kampala, Uganda, were classified based on their combination of HIV‐1 status and DMPA use: (i) HIV‐1–infected current DMPA users, (ii) HIV‐1–infected previous DMPA users, (iii) HIV‐1–infected nonhormonal‐contraceptive users, and (iv) HIV‐uninfected nonhormonal‐contraceptive users. All HIV‐1–infected women reported being ART‐naïve at baseline. BMD was measured at the lumbar spine, total hip, and femoral neck using DXA. Multivariate linear regression was used to assess the association between HIV‐1 and/or DMPA and BMD Z‐scores. Baseline data were analyzed for 452 HIV‐1–infected (220 nonhormonal users, and 177 current and 55 previous DMPA users) and 69 HIV‐1–uninfected nonhormonal‐contraceptive users. The mean age was 26.1 years (SD, 4.2) with a median duration of DMPA use among current users of 24.0 months [medians (interquartile range), 12‐48]. A higher proportion of HIV‐1–infected previous (12.7%) or current DMPA users (20.3%) and nonhormonal users (15.0%) had low BMD (Z‐score ≤−2 at any of the three sites) compared with age‐matched HIV‐1–uninfected women (2.9%). HIV‐1 infection and DMPA use were independently associated with significantly lower mean BMD Z‐scores at all sites, with the greatest difference being among HIV‐1–infected current DMPA users (5.6%–8.0%) versus uninfected nonhormonal users. Compared with non‐Hispanic White and Black women, the Ugandan local reference population had generally lower mean BMD at all sites. Newer treatment interventions are needed to mitigate BMD loss in HIV‐1–infected women in resource‐limited settings. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Blood Vessels and Vascular Niches in Bone Development and Physiological Remodeling

Recent advances in our understanding of blood vessels and vascular niches in bone convey their critical importance in regulating bone development and physiology. The contribution of blood vessels in bone functions and remodeling has recently gained enormous interest because of their therapeutic potential. The mammalian skeletal system performs multiple functions in the body to regulate growth, homeostasis and metabolism. Blood vessels provide support to various cell types in bone and maintain functional niches in the bone marrow microenvironment. Heterogeneity within blood vessels and niches indicate the importance of specialized vascular niches in regulating skeletal functions. In this review, we discuss physiology of bone vasculature and their specialized niches for hematopoietic stem cells and mesenchymal progenitor cells. We provide clinical and experimental information available on blood vessels during physiological bone remodeling.

Sports and Metabolic Bone Disease

Physical activity (PA) increases bone mass and bone strength through different mechanisms and also reduces the risk of falls in the elderly, through proprioception and balance training. The benefits seen in adolescence continue into adulthood. Exercise delays and attenuates the effects of osteoporosis, and particular sports activities may be recommended to improve bone mineral density (BMD) of the spine or regional BMD, improve balance, and prevent falls. Stress injuries related to exercise are more common in osteopenic and osteoporotic individuals.Sports activity may in some cases be detrimental for bone health, with nutrition restriction a frequent cause for negative effects of the practice of PA on bone. The examples are the so-called female athlete triad of menstrual dysfunction resulting in reduced estrogen levels, low energy due to malnutrition, and decreased BMD. A similar triad is described in male athletes. This review analyzes the effects of sport on bone metabolism and in particular its relationship with metabolic bone disease.

Does Physical Exercise Always Improve Bone Quality in Rats?

For decades, the osteogenic effect from different physical activities on bone in rodents remained uncertain. This literature review presents for the first time the effects on five exercise models (treadmill running, wheel running, swimming, resistance training and vibration modes) in three different experimental rat groups (males, females, osteopenic) on bone quality. The bone parameters presented are bone mineral density, micro-architectural and mechanical properties, and osteoblast/osteocyte and osteoclast parameters. This review shows that physical activities have a positive effect (65% of the results) on bone status, but we clearly observed a difference amongst the different protocols. Even if treadmill running is the most used protocol, the resistance training constitutes the first exercise model in term of osteogenic effects (87% of the whole results obtained on this model). The less osteogenic model is the vibration mode procedure (31%). It clearly appears that the gender plays a role on the bone response to swimming and wheel running exercises. Besides, we did not observe negative results in the osteopenic population with impact training, wheel running and vibration activities. Moreover, about osteoblast/osteocyte parameters, we conclude that high impact and resistance exercise (such jumps and tower climbing) seems to increase bone formation more than running or aerobic exercise. Among the different protocols, literature has shown that the treadmill running procedure mainly induces osteogenic effects on the viability of the osteocyte lineage in both males and females or ovariectomized rats; running in voluntary wheels contributes to a negative effect on bone metabolism in older male models; whole-body vertical vibration is not an osteogenic exercise in female and ovariectomized rats; whereas swimming provides controversial results in female models. For osteoclast parameters only, running in a voluntary wheel for old males, the treadmill running program at high intensity in ovariectomized rats, and the swimming program in a specific ovariectomy condition have detrimental consequences.

Impact of physical activity and exercise on bone health in patients with chronic kidney disease: a systematic review of observational and experimental studies

Background

Chronic Kidney Disease (CKD) patients frequently develop life-impairing bone mineral disorders. Despite the reported impact of exercise on bone health, systematic reviews of the evidence are lacking. This review examines the association of both physical activity (PA) and the effects of different exercise interventions with bone outcomes in CKD.

Methods

English-language publications in EBSCO, Web of Science and Scopus were searched up to May 2019, from which observational and experimental studies examining the relation between PA and the effect of regular exercise on bone-imaging or -outcomes in CKD stage 3–5 adults were included. All data were extracted and recorded using a spreadsheet by two review authors. The evidence quality was rated using the Cochrane risk of bias tool and a modified Newcastle-Ottawa scale.

Results

Six observational (4 cross-sectional, 2 longitudinal) and seven experimental (2 aerobic-, 5 resistance-exercise trials) studies were included, with an overall sample size of 367 and 215 patients, respectively. Judged risk of bias was low and unclear in most observational and experimental studies, respectively. PA was positively associated with bone mineral density at lumbar spine, femoral neck and total body, but not with bone biomarkers. Resistance exercise seems to improve bone mass at femoral neck and proximal femur, with improved bone formation and inhibited bone resorption observed, despite the inconsistency of results amongst different studies.

Conclusions

There is partial evidence supporting (i) a positive relation of PA and bone outcomes, and (ii) positive effects of resistance exercise on bone health in CKD. Prospective population studies and long-term RCT trials exploring different exercise modalities measuring bone-related parameters as endpoint are currently lacking.

Bone Mineral Density and Sports Participation

The objective of our study was to identify differences in bone mineral density (BMD) according to different sports among adolescents, as well as to identify assessments of relevant mediators. The sample consisted of 429 adolescents with a mean age of 13.3 ± 1.7 yr. The sports modalities that we evaluated were judo, karate, kung fu, swimming, basketball, and soccer. Nonsports group was composed of 111 adolescents. Bone density was assessed using dual-energy X-ray absorptiometry. Regarding BMD values, female engaged in karate had higher BMD values than girls from the no sports group (p = 0.01). Boys engaged in soccer and karate presented the highest BMD values than all the other groups (p = 0.01). The most relevant mediators were the body mass index and lean soft tissue for boys and girls. Different sports presented different results regarding BMD gains, which were influenced by body mass index and whole-body lean soft tissue.

SWIMMING AND BONE MINERAL DENSITY: A SPORT WITHOUT OSTEOGENIC STIMULATION?

ABSTRACT Introduction: The osteogenic effects generated by different sports are the subject of a growing number of research projects. Regular physical activity is one of the main recommendations for the stimulation of bone mineral density (BMD). However, evidence has shown that not all physical activities promote similar effects. In this context, the osteogenic effects of swimming need to be clarified. Objective: To verify and compare total and regional BMD levels between male and female swimming athletes and university non-athletes. Methods: The sample, composed of 60 participants of both sexes, was divided into two groups: 30 swimming athletes (GA): 15 men (22.2 ± 3.92 years; 73.61 ± 16.55 kg; 1.76 ± 0.08 m) and 15 women (21.91 ± 2.21 years; 53.15 ± 8.36 kg; 1.64 ± 0.06 m) and a control group (CG): 30 university non-athletes: 15 men (20.73 ± 1.27 years; 74.4 ± 5.54 kg, 1.74 ± 0.04 m) and 15 women (19.93 ± 2.05 years; 59.72 ± 1.33 kg; 1.63 ± 0.004 m). BMD (total, arms, legs, pelvis and spine) was measured using dual energy X-ray absorptiometry (DXA). The results were compared with one-way ANOVA using Scheffé's post hoc test, when necessary. Results: When compared with the women, the men of both groups presented superior results for all BMD values analyzed. In addition, GA had higher BMD of arms and spine when compared to the CG, both for males (p = 0.016 and p = 0.001, respectively) and females (p = 0.0001 and p = 0.011, respectively). Conclusions: The results of this study demonstrate that young male adults, athletes and non-athletes, present higher levels of BMD than their peers of the opposite sex. In addition, the results suggest that when undertaken for competitive purposes and with a weekly training volume of 12 hours or more, swimming may be beneficial for the bone development of young athletes when compared to non-athlete controls. Level of evidence III; Retrospective comparative study.

Gonadal hormones may predict structural bone fragility in elite female soccer player

Purpose: This study determined the impact of menstrual status on bone tissue in elite post-pubertal female soccer players over an entire season.Methods: Fifty-one elite female soccer players participated. At baseline, forty-one were assigned to the low hormonal androgenic profile (low-HAPL) and 10 to the high hormonal androgenic profile (high-HAPL).Results: An 8-month training program led to increased bone mineral density content (p<0.05). The low-HAPL athletes improved the Narrow neck average cortical thickness (ACT) by 1.4% and reduced the corresponding Buckling ratio (BR) by 2.6%, thus decreasing the fracture risk (p<0.05). The high-HAPL athletes decreased the Narrow neck ACT by 5.4% and increased the BR by 2.6%, increasing fracture risk (p<0.05). Differences were assigned as being "very likely beneficial" for the low-HAPL athletes, supported by very large (d=3.41) and large (d=1.58) effect sizes for the Narrow neck ACT and BR, respectively.Conclusion: A season of soccer training has induced bone geometry improvements in adolescent females. Bone health parameters improved in the two clusters. However, high-HAPL athletes decreased its resistance to loading compare to low-HAPL athletes. Even if female players do not present clinical symptoms related to their hormonal status, sport medicine physicians should pay attention to their structural bone fragility.

Short-Term Intermittent Hypoxic Resistance Training Does Not Impair Osteogenic Response in Sea Level Residents

Background: Osteogenic responses induced by training under hypoxia remain unclear. We aimed to investigate whether intermittent hypoxic resistance training affects osteogenic responses. Materials and Methods: Sixteen male participants underwent resistance training under normoxia (NRT; n = 7) or hypoxia (HRT; O₂ = 14.4%, n = 9), twice a week for 8 weeks. The HRT group exercised and rested for 30 minutes under hypoxia, with total hypoxic exposure time in one session of ∼60 minutes. At pre- and postexperiment, bone mineral density (BMD) of the whole body and right proximal femur was measured. At the first and last training sessions, bone alkaline phosphatase (BAP), osteocalcin (OC), cross-linked N-telopeptide of type I collagen (NTx), type I collagen cross-linked C-telopeptide (ICTP), interleukin-6 (IL-6), and blood lactate (La) concentration were analyzed at rest and postexercise. Results: BMD did not change with training and hypoxia. Although BAP, OC, and ICTP levels at rest significantly increased with training (p < 0.01, 0.05, and 0.05, respectively), they did not change with hypoxia. NTx and IL-6 did not change. Additionally, changing patterns of bone markers and La induced by a single bout of exercise were similar among groups in both training sessions. Conclusions: Short-term resistance training enhanced overall bone metabolism, regardless of the oxygen level. Hypoxia has no effects on osteogenic responses.

Sex differences in the patterning of age-related bone loss in the human hallucal metatarsal in rural and urban populations

OBJECTIVES

Age-degenerative features of the metatarsals are poorly known despite the importance of metatarsal bone properties for investigating mobility patterns. We assessed the role of habitual activity in shaping the patterning and magnitude of sexual dimorphism in age-related bone loss in the hallucal metatarsal.

MATERIALS AND METHODS

Cross-sections were extracted at midshaft from micro-computed tomography scan models of individuals from medieval rural (Abingdon Vineyard) and early industrial urban (Spitalfields) settings (n = 71). A suite of cross-sectional geometry dimensions and biomechanical properties were compared between populations.

RESULTS

The rural group display generally stronger and larger metatarsals that show a greater capacity to resist torsion and that have comparatively greater bending strength along the medio-lateral plane. Men in both groups show greater values of cortical area than women, but only in the urban group do men show lower magnitudes of age-related decline compared to females. Women in rural and urban populations show different patterns of age-related decline in bone mass, particularly old women in the urban group show a marked decline in cortical area that is absent for women in the rural group.

DISCUSSION

Lifetime exposure to hard, physical activity in an agricultural setting has contributed to the attainment of greater bone mass and stronger bones in young adults. Furthermore, over the life-course, less of this greater amount of bone is lost, such that sustained activity levels may have acted to buffer against age-related decline, and this is most pronounced for women, who are expected to experience greater bone loss later in life than men.

Determinants of Bone Health Status in a Multi-Ethnic Population in Klang Valley, Malaysia

Background and objectives: Studies on osteoporosis risk factors are limited in Malaysia, so this study assesses the factors associated with bone health assessed using dual-energy X-ray absorptiometry (DXA) among Malaysians aged ≥40 years. Subjects and Methods: Data on demography, medical history, dietary and lifestyle practices of 786 Malaysians (51.4% women) aged ≥40 years recruited in Klang Valley were obtained. Their body composition and bone health were determined using DXA. The association between risk factors and bone health status was assessed using binary logistic regression. Results: The prevalence of suboptimal bone health and osteoporosis was higher in women (59.4% and 16.1%) than men (40.8% and 8.4%). Overall, the predictors of suboptimal bone health and osteoporosis among the subjects were increased age and higher fat mass. Lower monthly income was positively associated with osteoporosis. Being menopausal was a risk factor for both suboptimal bone health and osteoporosis in women. Women with no formal education were more likely to get osteoporosis. Being a smoker and Chinese were positively related to suboptimal bone health among men. Meanwhile, predictors of osteoporosis among men were regular alcohol and dairy product consumption, higher fat mass and having a tertiary education. Conclusions: This study calls for immediate and effective interventions for middle-aged and elderly populations with risk factors to halt the progression of bone loss.

Bone Biomarker Response to Walking under Different Thermal Conditions in Older Adults

Endurance exercise can cause a decrease in serum ionized calcium (iCa) and increases in parathyroid hormone (PTH) and c-terminal telopeptide of type I collagen (CTX), which may be due to Ca loss in sweat.

PURPOSE

This study aimed to determine whether exercise in a warm environment exaggerates the decrease in iCa and increases in PTH and CTX compared with a cool environment in older adults.

METHODS

Twelve women and men 61-78 yr old performed two identical 60-min treadmill bouts at ~75% of maximal heart rate under warm and cool conditions. Serum iCa, PTH, and CTX were measured every 15 min starting 15 min before and continuing for 60 min after exercise. Sweat Ca loss was estimated from sweat volume and sweat Ca concentration.

RESULTS

Sweat volume was low and variable; there were no differences in sweat volume or Ca concentration between conditions. iCa decreased after 15 min of exercise, and the change was similar in both conditions. Increases in PTH (warm: 16.4, 95% confidence interval [CI] = 6.2, 26.5 pg·mL; cool: 17.3, 95% CI = 8.1, 26.4 pg·mL) and CTX (warm: 0.08, 95% CI = 0.05, 0.11 ng·mL; cool: 0.08, 95% CI = 0.01, 0.16 ng·mL) from before to immediately after exercise were statistically significant and similar between conditions. Adjusting for plasma volume shifts did not change the results.

CONCLUSION

The increases in PTH and CTX, despite the low sweat volume, suggest that dermal Ca loss is not a major factor in the decrease in iCa and increases in PTH and CTX observed during exercise in older adults.

An In Silico Model for the Prediction of Changes in Mineral Density in Cortical Bone Remodeling

An in silico model for the estimation of volumetric bone mineral density (vBMD) changes at a cortical bone site subjected to mechanobiological bone remodeling is proposed in this manuscript. Mechanisms of cell differentiation, receptor-ligand binding, mechanical signaling, and resorption or deposition of bone matrix were considered, therefore providing a comprehensive description of mechanobiological bone remodeling in the bone microenvironment and enabling the analysis of temporal evolution of disease or therapy scenarios. The proposed model is composed by five modules, namely, bone cells populations, mechanobiology, volume fractions and porosity, mineral density, and structural stiffness. The model is an extension of other models found in the literature because equations for the obtaining of cortical vBMD and the binding of parathyroid hormone (PTH) to parathyroid hormone 1 receptor are included. The proposed model showed a satisfactory agreement with the solutions of other in silico models found in the literature. Simulations of walking and running exercise routines were performed for the evaluation of model capability regarding the control of the numerical error and prediction of vBMD. The computational method used to solve the case study controlled the relative numerical error by less than 1 × 10-7 for approximately 1.7 × 106 time steps. The predicted values correlate with the concept of increasing BMD by vigorous physical activity; however, they contrast with the specific effect of physical activities on cortical vBMD.

WOMEN’S FEMORAL MASS CONTENT CORRELATES TO MUSCLE STRENGTH INDEPENDENTLY OF LEAN BODY MASS

ABSTRACT Introduction There is limited consensus regarding the recommendation of the most effective form of exercise for bone integrity, despite the fact that weight training exercise promotes an increase in muscle mass and strength as recurrent responses. However, strength variations in women do not depend on muscle mass development as they do in men, but strength enhancement has shown the potential to alter bone mineral content (BMC) for both sexes. Objective This study analyzed the potential of muscle strength, as well as that of whole-body and regional body composition, to associate femoral BMC in young women. Methods Fifteen female college students (aged 24.9 ± 7.2 years) were assessed for regional and whole-body composition using dual-energy X-ray absorptiometry (DXA). Maximum muscle strength was assessed by the one-repetition maximum (1RM) test in the following exercises: bench press (BP), lat pulldown (LP), knee flexion (KF), knee extension (KE) and 45° leg press (45LP). Linear regression analyzed BMC relationships with regional composition and 1RM values. Dispersion and error measures (R 2 aj and SEE), were tested, defining p ≤0.05. Results Among body composition variables, only total lean body mass was associated with femoral BMC values (R 2 aj = 0.37, SEE = 21.3 g). Regarding strength values, 1RM presented determination potential on femoral BMC in the CE exercise (R 2 aj = 0.46, SEE = 21.3 g). Conclusions Muscle strength aptitude in exercises for femoral regions is relevant to the femoral mineralization status, having associative potential that is similar to and independent of whole-body lean mass. Therefore, training routines to increase muscle strength in the femoral region are recommended. In addition, increasing muscle strength in different parts of the body may augment bone remodeling stimulus, since it can effectively alter total whole-body lean mass. Level of Evidence II; Development of diagnostic criteria in consecutive patients (with universally applied reference ‘‘gold’’ standard).

Contribution of High School Sport Participation to Young Adult Bone Strength

INTRODUCTION

Nearly 8 million American adolescents participate in sports. Participation declines in young adulthood.

PURPOSE

This study assessed longitudinal effects of high school sport participation and muscle power on young adult bone strength.

METHODS

Two hundred twenty-eight young adults from the Iowa Bone Development Study completed an interscholastic sport participation questionnaire. Current physical activity (PA) behaviors were assessed via questionnaire. Dual x-ray absorptiometry assessed hip areal bone mineral density and was used with hip structure analysis to estimate femoral neck section modulus and hip cross-sectional area. Peripheral quantitative computed tomography provided strength-strain index and bone strength index at 38% and 4% midshaft tibial sites, respectively. Vertical jump estimated muscle power at 17 yr. Sex-specific multiple linear regression predicted young adult bone outcomes based on sport participation groups. Mediation analysis analyzed the effects of muscle power on relationships between sport participation and bone strength.

RESULTS

At follow-up, males participating in any interscholastic sport had greater bone strength than males who did not participate in sport. The explained variability in bone outcomes was 2% to 16%. Females who participated in sports requiring muscle power had greater bone strength than females who did not participate in sports or females who participated in nonpower sports (explained variability was 4%-10%). Muscle power mediated 24.7% to 41% of the effect of sport participation on bone outcomes in males and 19.4% to 30% in females.

CONCLUSIONS

Former male interscholastic sport participants and female interscholastic power sport participants have stronger bones than peers even when adjusting for current PA. Muscle power did not fully explain differences in all bone outcomes, suggesting that sport participation has additional bone health benefits.

Skeletal loading score is associated with bone microarchitecture in young adults

Physical activity that involves high strain magnitudes and high rates of loading is reported to be most effective in eliciting an osteogenic bone response. Whether a history of participation in osteogenic activities during youth, as well as current participation in osteogenic activities, contributes to young adult bone microarchitecture and strength is unknown.

PURPOSE

We determined the association between a new skeletal loading (SkL) score reflecting physical activity from age 11 to adulthood, the bone specific physical activity questionnaire (BPAQ) and bone microarchitecture in young Black and White men and women.

METHODS

We conducted a cross-sectional study of young ([mean ± SD] 23.7 ± 3.3 years) Black (n = 51 women, n = 31 men) and White (n = 50 women, n = 49 men) adults. Microarchitecture and estimated bone strength (by micro-finite element analysis) were assessed at the ultradistal tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT). Physical activity questionnaires were administered and a SkL score was derived based on ground reaction force, rate of loading, frequency, duration, and life period of participation per activity from age 11 onwards. BPAQ score was also calculated. We used multiple linear regression to determine associations between both SkL score and BPAQ score and bone outcomes, adjusting for age, height, weight, sex, and race.

RESULTS

We found that SkL score, which accounts for current and historical physical activity, was significantly associated with most cortical bone parameters at the tibia including area, area fraction, porosity, thickness, and tissue mineral density (R² = 0.27-0.55, all p < 0.01). Further, trabecular thickness, separation, number, and bone mineral density (R² = 0.22-0.32, all p < 0.01), as well as stiffness and failure load (R² = 0.63-0.65, all p < 0.01), were associated with the SkL score. The BPAQ was also significantly associated with most bone parameters, but to a lesser degree than SkL score.

CONCLUSION

These findings suggest that among young adults, greater amounts of osteogenic physical activity, as assessed by the SkL score and BPAQ are associated with improved bone microarchitecture and strength. With the potential to predict bone parameters in young adults, these scores may ultimately serve to identify those most vulnerable to fracture.

Exercise Mitigates Bone Loss in Women With Severe Obesity After Roux-en-Y Gastric Bypass: A Randomized Controlled Trial

CONTEXT

Bone loss after bariatric surgery potentially could be mitigated by exercise.

OBJECTIVE

To investigate the role of exercise training (ET) in attenuating bariatric surgery-induced bone loss.

DESIGN

Randomized, controlled trial.

SETTING

Referral center for bariatric surgery.

PATIENTS

Seventy women with severe obesity, aged 25 to 55 years, who underwent Roux-en-Y gastric bypass (RYGB).

INTERVENTION

Supervised, 6-month, ET program after RYGB vs. standard of care (RYGB only).

OUTCOMES

Areal bone mineral density (aBMD) was the primary outcome. Bone microarchitecture, bone turnover, and biochemical markers were secondary outcomes.

RESULTS

Surgery significantly decreased femoral neck, total hip, distal radius, and whole body aBMD (P < 0.001); and increased bone turnover markers, including collagen type I C-telopeptide (CTX), procollagen type I N-propeptide (P1NP), sclerostin, and osteopontin (P < 0.05). Compared with RYGB only, exercise mitigated the percent loss of aBMD at femoral neck [estimated mean difference (EMD), -2.91%; P = 0.007;], total hip (EMD, -2.26%; P = 0.009), distal radius (EMD, -1.87%; P = 0.038), and cortical volumetric bone mineral density at distal radius (EMD, -2.09%; P = 0.024). Exercise also attenuated CTX (EMD, -0.20 ng/mL; P = 0.002), P1NP (EMD, -17.59 ng/mL; P = 0.024), and sclerostin levels (EMD, -610 pg/mL; P = 0.046) in comparison with RYGB. Exercise did not affect biochemical markers (e.g., 25(OH)D, calcium, intact PTH, phosphorus, and magnesium).

CONCLUSION

Exercise mitigated bariatric surgery-induced bone loss, possibly through mechanisms involving suppression in bone turnover and sclerostin. Exercise should be incorporated in postsurgery care to preserve bone mass.

Effects of Two Different Neuromuscular Training Protocols on Regional Bone Mass in Postmenopausal Women: A Randomized Controlled Trial

Background: Osteoporosis is a condition associated with a greater incidence of fractures, and one of the main health-related concerns in postmenopausal women. To counteract possible reductions in bone properties, physical exercise has been proposed as an effective strategy. Particularly, training interventions with a high osteogenic potential are recommended. Purpose: To analyze the effect of 24 weeks of whole-body vibration and multi-component training on lumbar spine and femoral neck bone mass, and to determine what type of training produces greater adaptations in postmenopausal women. Methods: A total of 38 women completed the study (Clinical Gov database ID: NCT01966562). Participants were randomly assigned to one of the study groups: whole-body vibration group (WBVG), multi-component training group (MTG), or control group (CG). The experimental groups performed a progressive 24-week training (3 sessions/week) program. Bone mineral density (BMD) and bone mineral content (BMC) at the lumbar spine and femoral neck were assessed by Dual-energy X-ray absorptiometry. Results: Significantly and clinically relevant increases in lumbar spine bone mass (BMD: F = 3.29; p = 0.03; +5.15%; BMC: F = 2.90; p = 0.05; +10.58%) were observed in WBVG. MTG showed clinically important pre-post-changes on lumbar spine BMC (+7.78%), although there was no statistical significance (F = 1.97; p = 0.14). At the femoral neck, no statistically significant increases on bone mass were obtained in either training group. No changes were obtained in any variable in the CG. Additionally, no statistically significant differences were found between groups. Conclusion: The results indicated that 24 weeks of supervised WBV and MT may counteract the rapid loss of bone mass after the cessation of menstruation, thus improving postmenopausal women bone health. However, in the absence of statistically significant differences between groups, it is not possible to determine which training protocol produces greater adaptations. Clinical Trial Registration: www.ClinicalTrialsgov, identifier: NCT01966562.

Bone mineral density in adolescent elite ballet dancers

BACKGROUND

Data documenting BMD in pre-professional adolescent ballet dancers is limited. This cross-sectional study assesses bone mineral density (BMD) in young adolescent elite ballet dancers and compares BMD values between males and females (with and without normal menarche) and body composition between dancers with and without low Z-score.

METHODS

Cross-sectional study of third year ballet students (female=23; male=15; mean age 14.7 years; SD: 0.5) of The Royal Ballet School of Antwerp (Belgium) training 22 hours a week. They completed questionnaires and underwent dual energy X-ray absorptiometry (DXA) to measure BMD and body composition. Each female participant completed questionnaires assessing menstrual status.

RESULTS

DXA revealed that 12 out of 38 (32%) of the dancers had Z-score <-1. On average, male dancers had a lower BMD compared to an age-matched reference population (mean Z-score -0.9; SD 0.5), with 7 out of 15 having Z-score <-1. Overall, absolute BMD values were highest in the legs, followed by spine and arms. Dancers with Z-score <-1 had a significantly lower total mass. 43% of female ballet dancers had not yet had their first period and 39% had oligomenorrhea, but no significant differences between groups was detected.

CONCLUSIONS

A third of adolescent elite ballet dancers had low to very low Z-score. Nearly 2 out of 3 dancers with a Z-score <-1 were males, showing that low BMD is not limited to female dancers. Among female dancers menstrual dysfunction was frequent, without apparent impact on BMD or body composition in the studied age group.

Is vigorous-intensity physical activity required for improving bone mass in adolescence? Findings from a Brazilian birth cohort

The association between moderate and vigorous physical activity throughout adolescence and areal bone density (aBMD) at 18 years of age was evaluated. Vigorous-intensity physical activity at 11, 15, and 18 years was associated with aBMD in early adulthood, especially in boys. Cross-sectional analyses showed a positive association between moderate physical activity and aBMD.

INTRODUCTION

To evaluate independent associations of moderate and vigorous physical activity (MPA, VPA) across adolescence with areal bone mineral density (aBMD).

METHODS

Physical activity (PA) was assessed at 11, 15, and 18 years of age by self-report and at 18 years by accelerometry in the 1993 Pelotas Birth Cohort Study. Time spent in MPA and VPA was determined using metabolic equivalents and specific cutoffs based on raw acceleration. Lumbar spine and femoral neck aBMD were measured by DXA at 18 years. Statistical analyses evaluated the association of MPA and VPA with aBMD, after adjusting for skin color, asset index, current height and age at menarche, and peak strain score (based on ground reaction forces of PA).

RESULTS

Lumbar spine and femoral neck aBMD were available for 3947 (49.9% of boys) and 3960 (49.6% of boys) individuals, respectively. Time spent in MPA at 11 and 15 years was not associated with aBMD. VPA at all time points was positively related to both lumbar spine and femoral neck aBMD in boys. Results were consistent for objectively measured VPA. Girls who achieved 75+ minutes/week of VPA in at least two follow-ups showed higher aBMD at 18 years of age. Boys who reached 75+ minutes/week of VPA at all follow-ups had on average 0.117 g/cm² (95% CI: 0.090; 0.144) higher femoral neck aBMD than those who never achieved this threshold.

CONCLUSIONS

Self-reported VPA but not MPA throughout adolescence was associated with aBMD. Recommendation for PA in young people should consider the importance of VPA.

BONE HEALTH, MUSCLE STRENGTH AND LEAN MASS: RELATIONSHIPS AND EXERCISE RECOMMENDATIONS

ABSTRACT Although muscle strength, lean mass and bone mineral content/density (BMC/BMD) are consistently reported as major outcomes of resistance training (RT), there is still no agreement on the RT regimen that is capable of achieving this result in men and women of different ages. This study describes the effects of RT on muscle strength, lean mass and bone mineralization, highlighting the relationships between them and analyzing the effectiveness of the RT protocol. Information searches were conducted in open access online academic libraries, using the BMC/BMD indices combined with muscle strength, body composition, and resistance exercises. The results showed changes in BMC/BMD in 72% of the studies published in the last decade. Among these, 77% recommended loads ≥ 80% 1-RM, 61% involved older individuals (> 60 years) and 61% had planning protocols of between 3 and 5 months (~12-20 weeks). The results also highlight muscle strength as a promising index of variations in BMC/BMD, with a moderate to high level of association (r2>0.5), which are specific for men and women in relation to the body region with best responsiveness. Among the studies published in last decade, about 61% had protocols involving only RT, and of these, 82% observed combined changes in BMC/BMD, body composition and muscle strength. This review therefore concludes that RT is important for improving muscle strength, increasing lean mass (whole-body and regional) and preventing risk factors that could impair the mineral integrity of the bone tissue, in individuals of all ages and sexes. Level of Evidence I; Systematic review of Level I RCTs (and study results were homogenous).

Dominant vs. non-dominant hip comparison in bone mineral density in young sporting athletes

To explore differences in bone mineral density (BMD) between dominant and non-dominant hip within levels of sport impact. BMD was higher in the non-dominant hip in high-impact sports, whereas the dominant hip had increased BMD for low-impact sports. The side-to-side differences were relatively small and not clinically relevant.

PURPOSE

It is unknown whether there is difference in BMD at the hip between dominant and non-dominant sides in young athletes. The aims of this study were to explore the dominant-non-dominant differences in hip BMD in young athletes participating in low- and high-impact sports and to assess the effect of ground force impact on BMD.

METHODS

Data was collected on University of Oxford athletes and controls (CG) between 2016 and 2018. Athletes were classified into two groups: high-impact sports (HIG) and low-impact sports (LIG). Total and regional measurements of both hips' BMD were recorded using a dual-energy X-ray absorptiometry (DXA). Linear regression method was used to assess differences in BMD between and within groups.

RESULTS

One hundred ninety-four athletes (HIG: n = 89, LIG: n = 105) and 48 controls were included in this study. Total hip and femoral neck BMD was higher in athletes compared to the CG (p < 0.01), with HIG recording highest levels of BMD. The BMD difference between the dominant and non-dominant sides was significant in the LIG, with BMD being higher in the dominant side. Conversly, BMD was higher in the non-dominant hip within the HIG. However, the hip asymmetries were not clinically relevant (%BMD difference < 3%). A significant interaction between side and sport group on BMD was observed.

CONCLUSIONS

High-impact sports had significantly higher BMD compared with low-impact sports and CG. BMD in the dominant hip was significantly higher for the LIG and lower in the HIG; however, differences were not clinically relevant.

The muscle-bone unit in adolescent swimmers

Most researchers adjust bone by lean mass when comparing swimmers with controls. This adjustment is done under the assumption that lean affects bone similarly in both groups. Nonetheless, we found that the muscle-bone association is uncoupled in swimmers, and consequently, researchers should avoid this adjustment when evaluating swimmers' bone.

INTRODUCTION

To examine the functional and structural muscle-bone unit in adolescent swimmers.

METHODS

Sixty-five swimmers (34 girls/31 boys) and 119 controls (51 girls/68 boys) participated in the study. Muscle cross-sectional area (MCSA), bone mineral content (BMC), and polar strength-strain index (SSIPOL) were measured in the non-dominant radius by peripheral quantitative computed tomography (pQCT). Subtotal BMC and lean mass were evaluated with dual-energy X-ray absorptiometry (DXA). Handgrip and isometric knee extension (IKE) tests were performed to determine muscle force. The effect of MCSA, lean and force on SSIPOL, and BMC were tested, and the functional and structural muscle-bone ratios of swimmers and controls were compared.

RESULTS

Both muscle size (MCSA and lean) and muscle force (handgrip and IKE) influenced BMC and SSIPOL in swimmers and controls similarly. Swimmers presented normal MCSA and lean values for their height, but when compared with controls, swimmers presented a higher amount of lean and MCSA for the same BMC or SSIPOL (structural muscle-bone unit). For the functional muscle-bone unit, different results were found for the lower and upper limbs, as no differences were found for the upper limbs, while for the lower limbs, swimmers presented higher muscle force for the same amount of BMC.

CONCLUSIONS

The contradictory results regarding BMC in swimmers found in previous studies could partly be explained with the findings of the present study that reinforce the idea that swimming is not an effective sport to practice regarding bone mass and that the muscle-bone unit is different in swimmers than in controls.

Exercise and resveratrol increase fracture resistance in the 3xTg-AD mouse model of Alzheimer's disease

Background

Alzheimer’s disease (AD) and osteoporosis are progressive diseases that affect the elderly population. Both conditions are associated with fracture risk that is greater than twice that of the healthy population. Resveratrol and exercise are two treatments that have been linked with attenuation of age-related diseases, including the risk of bone fractures. In this study, we test the hypothesis that these treatments improve fracture resistance in a mouse model representative of the AD condition.

Methods

Three-month-old male 3xTg-AD mice were treated for 4 months with resveratrol or exercise or both combined, and compared with wild type mice. Exercise training was performed on a treadmill at 15 m/min for 45 min/day, 5 days/week. Resveratrol was given at 4 g/kg diet in the form of pellets. Three-point bending, cross-sectional geometric, and fluorescence analyses were conducted on tibias and compared by treatment group.

Results

Tibias of 3xTg mice exhibited signs of diminished bone quality and fracture under less force than age-matched wild type mice (P < 0.05). Treatment with both resveratrol and exercise improved indicators of fracture resistance and bone quality in AD mice to levels comparable to that of wild type mice (P < 0.05).

Conclusions

The 3xTg mouse model of AD is at elevated risk for limb bone fracture compared to wild type controls. Treatment with resveratrol, exercise, or both in combination improves fracture resistance and cross-sectional geometric indicators of bone strength.

Effects of Zumba® and Aquagym on Bone Mass in Inactive Middle-Aged Women

Background and objectives: Regular exercise may stimulate bone formation and reduce the loss of bone mass in premenopausal women. This study aims to evaluate the effect of high-impact physical activity (Zumba^®) and low-impact physical activity (Aquagym) on bone mass in inactive middle-aged women. Materials and methods: Fifty-five healthy inactive women (30⁻50 years old) were recruited in Spain in 2016 and were randomly allocated into one of three groups: High impact group (HIG: n = 15), low impact group (LIG: n = 12) and control group (CG: n = 28). HIG and LIG were recruited from Madrid and the CG from Toledo. HIG and LIG completed a 12-week intervention program with three 40' sessions per week of Zumba^® or Aquagym; respectively. Dual energy X-ray absorptiometry (DXA) measured bone mineral content (BMC) and areal bone mineral density (aBMD) at total body less head (TBLH), lumbar spine and right hip. Results: Post-intervention adjusted data showed no significant differences in BMC between any of the groups nor in aBMD between HIG and LIG. Interestingly; significant differences for the HIG vs. CG were found in the change in total hip aBMD (1.76% vs. -0.44%), femoral neck aBMD (1.80% vs. -2.71%), and intertrochanter aBMD (2.03% vs. -0.50%). Moreover, significant differences for the LIG vs. CG were also found in the change in femoral neck aBMD (-0.54% vs. -2.71%). Conclusions: The regular practice of Zumba^® and Aquagym might reduce the progressive deterioration of bone mass in inactive middle-aged women.

The Effectiveness of Physical Exercise on Bone Density in Osteoporotic Patients

Physical exercise is considered an effective means to stimulate bone osteogenesis in osteoporotic patients. The authors reviewed the current literature to define the most appropriate features of exercise for increasing bone density in osteoporotic patients. Two types emerged: (1) weight-bearing aerobic exercises, i.e., walking, stair climbing, jogging, and Tai Chi. Walking alone did not appear to improve bone mass; however it is able to limit its progressive loss. In fact, in order for the weight-bearing exercises to be effective, they must reach the mechanical intensity useful to determine an important ground reaction force. (2) Strength and resistance exercises: these are carried out with loading (lifting weights) or without (swimming, cycling). For this type of exercise to be effective a joint reaction force superior to common daily activity with sensitive muscle strengthening must be determined. These exercises appear extremely site-specific, able to increase muscle mass and BMD only in the stimulated body regions. Other suggested protocols are multicomponent exercises and whole body vibration. Multicomponent exercises consist of a combination of different methods (aerobics, strengthening, progressive resistance, balancing, and dancing) aimed at increasing or preserving bone mass. These exercises seem particularly indicated in deteriorating elderly patients, often not able to perform exercises of pure reinforcement. However, for these protocols to be effective they must always contain a proportion of strengthening and resistance exercises. Given the variability of the protocols and outcome measures, the results of these methods are difficult to quantify. Training with whole body vibration (WBV): these exercises are performed with dedicated devices, and while it seems they have effect on enhancing muscle strength, controversial findings on improvement of BMD were reported. WBV seems to provide good results, especially in improving balance and reducing the risk of falling; in this, WBV appears more efficient than simply walking. Nevertheless, contraindications typical of senility should be taken into account.

Setting larger session duration goals is associated with greater future physical activity

Many national (US) and International guidelines for physical activity provide guidance that under-active and sedentary adults can begin by accumulating moderate-to-vigorous physical activity (MVPA) in bouts as brief as 10 minutes. This guidance fits well with Goal Setting theory in that goals should be realistic and achievable, and is also consistent with Social Cognitive theory since achieving small goals should boost self-efficacy and thus, encourage continued physical activity. In contrast, Behavioral Economics might suggest that fewer, longer bouts would be more conducive to the adoption of physical activity due to the costs incurred with each separate bout of MVPA. This paper examines patterns of MVPA adoption among a sample of under-active adults from the perspective of goal setting theory and behavioral economics to explore specific strategies to help people who are in the early stages of PA activity adoption. Under-active men and women (N = 225; mean age = 46 ± 10; mean BMI = 28 ± 4.48) who enrolled in a PA intervention participated in a single goal setting session at enrollment. Participants were encouraged to set realistic goals and to increase their activity to meet national recommendations (150 minutes/week of moderate to vigorous physical activity [MVPA]) by the 6-month follow up. This process included identifying a specific frequency goal (days/week) and session duration goal (minutes/day). At baseline, participants reported average weekly MVPA of 14.59 min (± 24), which increased to an average of 140.52 (± 143.55) at 6 months. MVPA goals at baseline averaged 33.24 min/day (± 18.08) and 3.85 days/week (± 1.31). Analyses showed that longer session duration goals set at baseline were associated with more weekly minutes of MVPA at 6 months (b = 1.26, SE = 0.58, t = 2.17, p = 0.03). There was no significant association between goals for number of days per week (frequency) or total minutes of weekly MVPA (minutes x frequency) and MVPA at 6 months. Widely promoted guidelines for uptake of physical activity recommend accumulating physical activity in bouts as short as 10 minutes. This recommendation may ultimately hinder the adoption of physical activity among under-active and sedentary individuals. For the purposes of behavioral adoption of MVPA, more ambitious session duration goals appear to result in higher levels of physical activity participation.

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.

Abdominal Obesity is Associated With Lower Bone Mineral Density in Non-Weight-Bearing Site in Korean Men

This research aimed to investigate the relationship between abdominal obesity and lower bone mineral density (BMD) at non-weight-bearing site in Korean men using data from the Korea National Health and Nutrition Examination Survey, which is a nationwide cross-sectional survey. The study population (n = 5,941) was selected from the 2009–2010 survey. Abdominal obesity in men was defined as waist circumference ⩾ 90 cm. Lower BMD state was defined as having T-score of −2.5 or below. To investigate the association, multiple logistic regression analysis was performed. Abdominal obesity was highly associated with lower non-weight-bearing site (lumbar spine [LS]) BMD after adjustment (odds ratio [OR] 1.61, 95% CI [1.06, 2.44], p = .026). Also, abdominal obesity was a risk factor for lower LS BMD, especially in age groups of those in their 20s and those over 60s (OR 5.53, 95% CI [1.27, 24.07], p = .023 for 20s; OR 2.19, 95% CI [1.19, 4.02], p = .011 for 60 years or older). Abdominal obesity in Korean men is associated with lower BMD at non-weight-bearing site (LS), especially in younger and older age groups. Further research might be recommended to prove the mechanism or causality.

Differential effects of high-fat diet and exercise training on bone and energy metabolism

Bone microarchitecture and strength are impaired by obesity and physical inactivity, but the underlying molecular regulation of bone metabolism in response to these factors is not well understood. Therefore, we analyzed bone and energy metabolism in male mice fed a high-fat or standard chow diet for 12 weeks with or without free access to running wheels. High-fat diet (HFD) mimicked the human condition of obesity and insulin resistance, including symptoms such as elevated serum glucose and insulin levels and reduced insulin-stimulated glucose uptake into muscle and adipose tissue. Interestingly, HFD also decreased (-44%) glucose uptake into bone marrow. Bone mass was reduced (-45%) by HFD due to a diminished (-45%) bone remodeling rate. Bone matrix quality aspects, such as biomechanical stability, were additionally decreased. Concurrently, the bone marrow adiposity increased (+63%) in response to a HFD. Further, we detected elevated expression of the Wnt signaling inhibitor dickkopf-1 (Dkk-1, +42%) in mice fed a HFD, but this was not reflected in serum samples obtained from obese humans. In mice, exercise attenuated the adverse effects of HFD by reversing the glucose uptake into bone marrow, improving the bone mass and bone matrix quality while decreasing the bone marrow adiposity. This data shows that exercise prevents some, but not all of the negative effects of HFD on bone health and suggests that insulin signaling in bone marrow and Dkk-1 signaling may be involved in the pathogenesis of bone loss induced by HFD.

Genetic variation in Wnt/β-catenin and ER signalling pathways in female and male elite dancers and its associations with low bone mineral density: a cross-section and longitudinal study

The association of genetic polymorphisms with low bone mineral density in elite athletes have not been considered previously. The present study found that bone mass phenotypes in elite and pre-elite dancers are related to genetic variants at the Wnt/β-catenin and ER pathways.

INTRODUCTION

Some athletes (e.g. gymnasts, dancers, swimmers) are at increased risk for low bone mineral density (BMD) which, if untreated, can lead to osteoporosis. To investigate the association of genetic polymorphisms in the oestrogen receptor (ER) and the Wnt/β-catenin signalling pathways with low BMD in elite and pre-elite dancers (impact sport athletes).

METHODS

The study included three phases: (1) 151 elite and pre-elite dancers were screened for the presence of low BMD and traditional osteoporosis risk factors (low body weight, menstrual disturbances, low energy availability); (2) a genetic association study was conducted in 151 elite and pre-elite dancers and age- and sex- controls; (3) serum sclerostin was measured in 101 pre-elite dancers and age- and sex-matched controls within a 3-year period.

RESULTS

Eighty dancers revealed low BMD: 56.3% had at least one traditional osteoporosis risk factor, whereas 28.6% did not display any risk factor (37.2% revealed traditional osteoporosis risk factors, but had normal BMD). Body weight, menstrual disturbances and energy availability did not fully predict bone mass acquisition. Instead, genetic polymorphisms in the ER and Wnt/β-catenin pathways were found to be risk factors for low BMD in elite dancers. Sclerostin was significantly increased in dancers compared to controls during the 3-year follow-up (p < 0.05).

CONCLUSIONS

Elite and pre-elite dancers demonstrate high prevalence of low BMD, which is likely related to genetic variants at the Wnt/β-catenin and ER pathways and not to factors usually associated with BMD in athletes (body weight, menstrual disturbances, energy deficiency).

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.

Management of Reduced Bone Mineral Density in HIV: Pharmacological Challenges and the Role of Exercise

Low bone mineral density is becoming more common among people living with HIV following the use of current antiretroviral therapy drugs such as tenofovir. Although pharmacological therapies used to treat low bone mineral density are associated with adverse effects and may increase the pill burden in people living with HIV who are already burdened by antiretroviral therapy drugs, non-pharmacological strategies to prevent and treat reduced bone mineral density resulting from antiretroviral therapy drugs in people living with HIV have not been fully explored. Despite evidence that exercise is effective in increasing bone mineral density, effects of exercise on low bone mineral density resulting from antiretroviral therapy drugs in HIV infected individuals are still unknown. This review highlights gaps in the strategies used to manage reduced bone mineral density resulting from antiretroviral therapy drugs and focuses on exercise as an alternative or adjunctive strategy.

High-Impact Mechanical Loading Increases Bone Material Strength in Postmenopausal Women-A 3-Month Intervention Study

Bone adapts to loading in several ways, including redistributing bone mass and altered geometry and microarchitecture. Because of previous methodological limitations, it is not known how the bone material strength is affected by mechanical loading in humans. The aim of this study was to investigate the effect of a 3-month unilateral high-impact exercise program on bone material properties and microarchitecture in healthy postmenopausal women. A total of 20 healthy and inactive postmenopausal women (aged 55.6 ± 2.3 years [mean ± SD]) were included and asked to perform an exercise program of daily one-legged jumps (with incremental number, from 3×10 to 4×20 jumps/d) during 3 months. All participants were asked to register their performed jumps in a structured daily diary. The participants chose one leg as the intervention leg and the other leg was used as control. The operators were blinded to the participant's choice of leg for intervention. The predefined primary outcome was change in bone material strength index (BMSi), measured at the mid tibia with a handheld reference probe indentation instrument (OsteoProbe). Bone microstructure, geometry, and density were measured with high-resolution peripheral quantitative computed tomography (XtremeCT) at the ultradistal and at 14% of the tibia bone length (distal). Differences were analyzed by related samples Wilcoxon signed rank test. The overall compliance to the jumping program was 93.6%. Relative to the control leg, BMSi of the intervention leg increased 7% or 0.89 SD (p = 0.046), but no differences were found for any of the XtremeCT-derived bone parameters. In conclusion, a unilateral high-impact loading program increased BMSi in postmenopausal women rapidly without affecting bone microstructure, geometry, or density, indicating that intense mechanical loading has the ability to rapidly improve bone material properties before changes in bone mass or structure. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

The effects of resistance training volume on osteosarcopenic obesity in older women

The aim of this study was to analyze the effects of resistance training (RT) performed with 1 or 3 sets per exercise on osteosarcopenic obesity (OSO) syndrome parameters in older women. Sixty-two older women (68.0 ± 4.3 years, 26.8 ± 4.4 kg/m2) participated in a 12-week RT program. Participants were randomly assigned into one of the three groups: two training groups that performed either 1 set (G1S, n = 21) or 3 sets (G3S, n = 20) 3 times weekly, or a control group (CG, n = 21). Body composition was assessed by dual X-ray absorptiometry, strength was evaluated by 1 repetition maximum testing. The G3S presented significantly higher strength changes than G1S. The changes for percentage of body fat were higher for G3S compared to G1S. There was no difference in skeletal muscle mass between G3S and G1S, however both training groups displayed greater increases in this outcome compared to CG. There was no effect for bone mineral density. The overall analysis indicated higher (P < 0.05) positive changes for G3S than G1S (composed Z-score: G3S = 0.62 ± 0.40; G1S = 0.11 ± 0.48). The results suggest that a 12-week RT period is effective to improve the risk factors of OSO, and that 3 sets induce higher improvements than a single set.

A high anticholinergic burden is associated with a history of falls in the previous year in middle-aged women: findings from the Aberdeen Prospective Osteoporosis Screening Study

PURPOSE

To examine the cross-sectional association between anticholinergic medication burden (ACB) and a history of falls, bone mineral density, and low trauma fractures in middle-aged women aged under 65 years from the Aberdeen Prospective Osteoporosis Screening Study.

METHODS

ACB (0 = none, 1 = possible, ≥2 = definite) was calculated from medication use for 3883 Caucasian women [mean age (SD) = 54.3 (2.3) years] attending the second Aberdeen Prospective Osteoporosis Screening Study visit (1997-2000). Outcomes were examined using logistic regression. Model adjustments were selected a priori based on expert opinion.

RESULTS

Of 3883 participants, 3293 scored ACB = 0, 328 scored ACB = 1, and 262 scored ACB ≥2. High ACB burden (≥2) was associated with increased odds (ACB = 0 reference) for falls (fully adjusted odds ratio [95% confidence intervals] = 1.81 [1.25-2.62]; P = 0.002) and having low bone mineral density (lowest quintile-20%) at Ward's triangle (3.22 [1.30-7.99]; P = 0.01). A history of falls over the year prior to the study visit in participants with ACB score ≥2 was 32 per 100. For ACB categories 1 and 0, a history of falls per 100 was 21 and 22, respectively.

CONCLUSIONS

The risk of falling associated with ACB observed in older age may also extend to middle-aged women.

Serum vitamin D and body composition in adults undergoing fitness assessments: A correlation study

The purpose of this descriptive study was to assess serum levels of 25(OH) vitamin D₃ (25(OH)D) in participants who voluntarily participated in a fitness assessment and correlate this with muscular strength, weekly exercise, overall body composition, and dietary intake of vitamin D and calcium. Thirty-six participants were recruited. Anthropometric measurements and handgrip strength were taken with blood analyses completed utilizing 25-hydroxyvitamin D assay. A dietary screening survey was used to assess calcium and vitamin D intake. All data collection was completed at time of assessment appointment. Statistical analyses completed utilized Pearson’s and Kendall’s Tau correlation, with level of significance set at p < 0.05. Twenty-two percent of our sample were 25(OH)D deficient and 33% 25(OH)D insufficient, with 16% consuming adequate vitamin D and 5% consuming adequate calcium. Eight of the females and one male had below average DXA assessments for bone health. Vitamin D intake was significantly correlated with serum 25(OH)D levels (τ = 0.29, p<0.01). In females there was an inverse relationship between 25(OH)D and weight (r = -0.45, p<0.05). Thirty-one percent of participants had higher than desirable waist circumference and were 25(OH)D insufficient or deficient. This sample had a high rate of 25(OH)D insufficiency and deficiency, with most not consuming adequate amounts of calcium and vitamin D. Normalizing serum 25(OH)D through food and supplements has the potential to positively impact several parameters of an individual’s health including weight status, visceral adiposity and waist circumference, and bone health.

Long-Term Quantitative Evaluation of Muscle and Bone Wasting Induced by Botulinum Toxin in Mice Using Microcomputed Tomography

Muscle and bone masses are highly correlated and muscles impose large loads on bone. Muscle wasting that accompanies bone loss has been poorly investigated. 21 female mice were spread into seven groups. At day 0, 18 mice received Botulinum toxin (BTX) injection in the quadriceps muscle to induce paralysis of the right hind limb; the left contralateral side was used as control. Mice were sacrificed at 7, 14, 21, 28, 56 and 90 days post-injection. A remaining group was sacrificed at day 0. Trabecular bone volume was determined by microcomputed tomography (microCT) at the distal femur and tibia proximal metaphyses on both sides. Limbs were immersed in an HgCl₂ solution allowing muscle visualization by microCT. On 2D sections, the cross-sectional areas and form-factors were measured for the quadriceps at mid-thigh and gastrocnemius at mid-leg and these muscles were dissected and weighed. Bone volume decreased in the paralysed side. Bone loss was maximal at 56 days followed by recuperation at 90 days. The cross-sectional areas of gastrocnemius and quadriceps were significantly lower in the paralysed limb from 7 days; the decrease was maximum at 21 days for the gastrocnemius and 28 days for the quadriceps. No difference in form-factors was found between the two limbs. Similar results were obtained with the anatomical method and significant correlations were obtained between the two methods. Quantitative analysis of muscle loss and recovery was possible by microCT after using a metallic contrast agent. Loss of bone secondary to muscle wastage induced by BTX and recovery showed a parallel evolution for bone and muscles.

A systematic review of the exercise effect on bone health: the importance of assessing mechanical loading in perimenopausal and postmenopausal women

OBJECTIVE

The aims of this systematic review were to determine the general effects of exercise on areal bone mineral density (BMD) in perimenopausal and postmenopausal women, and to provide information on the most suitable bone-loading exercise regimens that may improve bone health in this population group.

METHODS

A computerized, systematic literature search was performed in the electronic databases PubMed, Web of Science, CINAHL, SPORTDiscus, and The Cochrane Library, from January 2005 to November 2015, to identify all randomized controlled trials related to exercise in perimenopausal and postmenopausal women. The initial search identified 915 studies, with a final yield of 10 studies. Only randomized controlled trials that examined the effects of exercise programs longer than 24 weeks in women aged 35 to 70 years were included. The 10 studies quantified at least BMD and described training variables adequately (training period, frequency, volume, intensity).

RESULTS

Ten studies with moderate quality evidence (6.4 ± 1.8 points, range 4-9) were included. Significant changes in lumbar and femoral neck BMD were found mainly with high-impact exercise and whole body vibration interventions.

CONCLUSIONS

While training effects must be interpreted with caution because of the heterogeneity of the protocols and exercises performed, this systematic review confirmed the effectiveness of impact exercises combined with other forms of training (vibration or strength training) to preserve BMD in perimenopausal and postmenopausal women. Despite the results possibly not representing a general dose-response relationship, we highlight the importance of quantifying loading intensity and frequency by means of accelerometry as these parameters are determinants for bone adaptation.

Are consumption of dairy products and physical activity independently related to bone mineral density of 6-year-old children? Longitudinal and cross-sectional analyses in a birth cohort from Brazil

OBJECTIVE

To evaluate cross-sectional and longitudinal associations of consumption of dairy products and physical activity (PA) with bone mineral density (BMD).

DESIGN

Cohort study with children from the 2004 Pelotas (Brazil) Birth Cohort.

SETTING

Pelotas, a medium-sized Brazilian city.

SUBJECTS

The study started in 2004 and mothers/children were interviewed/measured periodically from birth to age 6 years. PA was measured by maternal proxy at 4 and 6 years and by accelerometry at 6 years. Consumption of dairy products was measured using 24 h food recall (at 4 years) and FFQ (at 6 years). Total-body and lumbar-spine BMD (g/cm2) were measured by dual-energy X-ray absorptiometry.

RESULTS

At 6 years, BMD was measured in 3444 children and 2636 children provided data on objectively measured PA by accelerometry. Consumption of dairy products at 4 years was associated with higher lumbar-spine BMD at 6 years in boys, while current consumption was positively associated with BMD in both sexes (P < 0·001). PA assessed by maternal report at 4 and 6 years of age was associated with higher BMD at 6 years in boys. PA assessed by accelerometry was positively related to total-body and lumbar-spine BMD in boys and lumbar-spine BMD in girls. We did not find evidence for an interaction between PA and consumption of dairy products on BMD.

CONCLUSIONS

We observed positive and independent longitudinal and cross-sectional associations between consumption of dairy products and PA with BMD in the total body and at the lumbar spine in young children.

Sports participation and fracture in older Australian men

Older men who participated in a sporting activity were less likely to sustain any fracture or major osteoporotic fracture over a 6-year follow-up period.

PURPOSE

Regular weight-bearing physical activity can reduce fracture risk through an increase in bone strength, as well as reducing falls risk by improving muscle strength and balance. In this study, we aimed to determine whether a specific type of physical activity, sports participation, reduces fracture risk in older Australian men.

METHODS

Participation in sporting activities was documented for men aged 60 years and over enrolled in the Geelong Osteoporosis Study situated in south-eastern Australia. Fractures at any skeletal site (excluding skull, face, fingers and toes) and major osteoporotic fracture sites (MOF; wrist, proximal humerus, spine and hip) were ascertained through examination of radiological reports (median follow-up 6.63 years, IQR 5.58-7.29). Multivariable logistic regression was used to investigate the association between sports participation (either binary or continuous) and any fracture or MOF. Other clinical measures and lifestyle variables (such as comorbidity, falls and mobility) were included as potential confounders.

RESULTS

During follow-up, 82 of 656 men (12.5%) sustained at least one fracture at any site and 58 sustained at least one MOF (8.8%). Of those who did and did not fracture (any site), 17 (20.7%) and 204 (35.5%) participated in at least one sporting activity. For MOF, the values were 11 (19.0%) and 210 (35.1%), respectively. Participation in any sporting activity was associated with a reduction in the likelihood of any fracture during follow-up (unadjusted: OR 0.47, 95%CI 0.27-0.83), which persisted after adjusting for other factors (adjusted: OR 0.52, 95%CI 0.29-0.91). The results for MOF were similar (unadjusted: OR 0.43, 0.22-0.85; adjusted 0.48, 0.24-0.95). When considering sports participation as a continuous variable, a trend was observed (adjusted: p = 0.051 and p = 0.059 for any and MOF, respectively). A sensitivity analysis showed similar results when excluding men who reported using a walking aid.

CONCLUSIONS

In this group of older men, participation in sporting activity was associated with a reduced risk of fracture during the subsequent follow-up period.

Impact of physical exercise in cancer survivors during and after antineoplastic treatments

Cancer patients experience symptoms and adverse effects of treatments that may last even after the end of treatments. Exercise is a safe, non-pharmacological and cost-effective therapy that can provide several health benefits in cancer patient and survivors, reducing cancer symptoms and cancer treatment side effects. The purpose of this review is to describe how the physical exercise is capable to reduce cancer symptoms and cancer treatment side effects. We realized a pragmatic classification of symptoms, dividing them into physical, psychological and psycho-physical aspects. For each symptom we discuss causes, therapies, we analyse the effects of physical exercise and we summarize the most effective type of exercise to reduce the symptoms. This review also points out what are the difficulties that patients and survivors face during the practice of physical activity and provides some solutions to overcome these barriers. Related to each specific cancer, it emerges that type, frequency and intensity of physical exercise could be prescribed and supervised as a therapeutic program, like it occurs for the type, dose and duration of a drug treatment.

Bone metabolism markers and vitamin D in adolescent cyclists

This study aimed to describe bone metabolic activity in adolescent competitive cyclists compared to age-matched controls. The main result is that younger subjects present a higher bone turnover than the older ones. Moreover, cyclists under the age of 17 have higher scores on all markers than age-matched controls.

PURPOSE

The purpose of this study was to describe bone metabolic activity in adolescent competitive cyclists compared to age-matched controls.

METHODS

Twenty-two male adolescent cyclists between 14 and 20 years (y) and 20 age-matched controls participated in this study. Serum osteocalcin (OC), aminoterminal propeptide of type I procollagen (PINP), and β-isomerized C-telopeptides (β-CTX) were analyzed by electrochemiluminescence immunoassay (ECLIA); plasma 25 hydroxyvitamin D [25(OH)D] was analyzed by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Analysis of variance revealed no significant differences in bone metabolism markers and vitamin D between cyclists and controls. Cyclists over 17 y had a significantly lower concentration in bone formation and resorption biochemical markers compared to cyclists under 17 y (all P < 0.05). Moreover, controls over 17 y presented lower concentration for PINP (P < 0.05) compared to their peers under 17 y. Comparisons between cyclists and controls under 17 y revealed higher concentrations of OC and PINP (P < 0.05) in cyclists. Group interaction by age was found for OC, PINP, and β-CTX (P < 0.01). Cyclists over 17 y had higher concentrations of [25(OH)D] (P < 0.05) than age-matched controls.

CONCLUSIONS

The present results support the idea that cycling during adolescence may be associated to a decrease in bone turnover that may affect bone health later in life.