Non-weightbearing exercise may increase lumbar spine bone mineral density in healthy postmenopausal women

Exercise training and bone mineral density in postmenopausal women: an updated systematic review and meta-analysis of intervention studies with emphasis on potential moderators

The aim of this systematic review and meta-analysis was (1) to determine exercise effects on bone mineral density (BMD) in postmenopausal women and (2) to address the corresponding implication of bone and menopausal status or supervision in postmenopausal women. A comprehensive search of eight electronic databases according to the PRISMA statement up to August 9, 2022, included controlled exercise trials ≥ 6 months. BMD changes (standardized mean differences: SMD) at the lumbar spine (LS), femoral neck (FN), and total hip (TH) were considered as outcomes. Study group comparisons were conducted for osteopenia/osteoporosis versus normal BMD, early versus late postmenopausal women, and predominantly supervised versus predominantly non-supervised study arms. We applied an inverse heterogeneity (IVhet) model. In summary, 80 studies involving 94 training and 80 control groups with a pooled number of 5581 participants were eligible. The IVhet model determined SMDs of 0.29 (95% CI: 0.16-0.42), 0.27 (95% CI: 0.16-0.39), and 0.41 (95% CI: 0.30-0.52) for LS, FN, and THBMD, respectively. Heterogeneity between the trial results varied from low (I2 = 20%, TH BMD) to substantial (I2 = 68%, LS-BMD). Evidence for publication bias/small study effects was negligibly low (FN-, TH-BMD) to high (LSBMD). We observed no significant differences (p > .09) for exercise effects on LS-, FN-, or TH-BMD-LS between studies/study arms with or without osteopenia/osteoporosis, early versus late postmenopausal women, or predominantly supervised versus non-supervised exercise programs. Using robust statistical methods, the present work provides further evidence for a positive effect of exercise on BMD in postmenopausal women. Differences in bone status (osteopenia/osteoporosis versus normal bone), menopausal status (early versus late postmenopausal), and supervision (yes versus no) did not significantly affect the exercise effects on BMD at LS or proximal femur.

Microgravity-Related Changes in Bone Density and Treatment Options: A Systematic Review

Space travelers are exposed to microgravity (µg), which induces enhanced bone loss compared to the age-related bone loss on Earth. Microgravity promotes an increased bone turnover, and this obstructs space exploration. This bone loss can be slowed down by exercise on treadmills or resistive apparatus. The objective of this systematic review is to provide a current overview of the state of the art of the field of bone loss in space and possible treatment options thereof. A total of 482 unique studies were searched through PubMed and Scopus, and 37 studies met the eligibility criteria. The studies showed that, despite increased bone formation during µg, the increase in bone resorption was greater. Different types of exercise and pharmacological treatments with bisphosphonates, RANKL antibody (receptor activator of nuclear factor κβ ligand antibody), proteasome inhibitor, pan-caspase inhibitor, and interleukin-6 monoclonal antibody decrease bone resorption and promote bone formation. Additionally, recombinant irisin, cell-free fat extract, cyclic mechanical stretch-treated bone mesenchymal stem cell-derived exosomes, and strontium-containing hydroxyapatite nanoparticles also show some positive effects on bone loss.

Effects of physical exercise on bone mineral density in older postmenopausal women: a systematic review and meta-analysis of randomized controlled trials

Osteoporosis or decreased bone mineral density (BMD) is the most important risk factor for fractures, especially in older postmenopausal women (PMW). However, the interactions between exercise training and bone mineral density are not completely understood. We evaluated the effects of physical exercise on BMD in women aged ≥ 60 years postmenopausal.

PURPOSE

This systematic review and meta-analysis sets out to determine the effects of physical exercise on BMD in older postmenopausal women.

METHODS

A systematic search was conducted in Medline, Science Direct, Cochrane, PubMed, CINAHL, Google Scholar, Scopus, and ProQuest up to December 25, 2021. Fifty-three studies, which assessed a total of 2896 participants (mean age: between 60 and 82 years), were included and analyzed using a random-effects model to estimate weighted mean differences (WMD) with 95% confidence intervals (CI).

RESULTS

The meta-analysis found that exercise training significantly (p < 0.05) increased femoral neck (WMD: 0.01 g/cm²; 95% CI, 0.00 to 0.01], p = 0.0005; I² = 57%; p < 0.0001), lumbar spine (WMD: 0.01 g/cm², 95% CI, 0.01 to 0.02], I² = 81%; p = 0.0001), and trochanter (WMD: 0.01 g/cm², 95% CI 0.00, 0.02]; p = 0.009; I² = 17%; p = 0.23). There were no significant differences between the intervention and control groups for total body and total hip BMD.

CONCLUSION

Our findings suggest that exercise training may improve bone mineral density in older PMW. This improvement is mediated by increases in the femoral neck, lumbar spine, and trochanter BMD. Further long-term studies are required to confirm these findings.

Effect of Exercise Training on Bone Mineral Density in Post-menopausal Women: A Systematic Review and Meta-Analysis of Intervention Studies

Osteoporosis is a major health problem in post-menopausal women (PMW). Exercise training is considered a cost-effective strategy to prevent osteoporosis in middle aged-older people. The purpose of this study is to summarize the effect of exercise on BMD among PMW. A comprehensive search of electronic databases was conducted through PubMed, Scopus, Web of Science, Cochrane, Science Direct, Eric, ProQuest, and Primo. BMD changes (standardized mean differences: SMD) of the lumbar spine (LS) femoral neck (FN) and/or total hip were considered as outcome measures. After subgroup categorization, statistical methods were used to combine data and compare subgroups. Seventy-five studies were included. The pooled number of participants was 5,300 (intervention group: n = 2,901, control group: n = 2,399). The pooled estimate of random effect analysis was SMD = 0.37, 95%-CI: 0.25–0.50, SMD = 0.33, 95%-CI: 0.23–0.43, and SMD = 0.40, 95%-CI: 0.28–0.51 for LS, FN, and total Hip-BMD, respectively. In the present meta-analysis, there was a significant (p < 0.001), but rather low effect (SMD = 0.33–0.40) of exercise on BMD at LS and proximal femur. A large variation among the single study findings was observed, with highly effective studies but also studies that trigger significant negative results. These findings can be largely attributed to differences among the exercise protocols of the studies. Findings suggest that the true effect of exercise on BMD is diluted by a considerable amount of studies with inadequate exercise protocols.

Addition of aerobic exercise to a weight loss program increases BMD, with an associated reduction in inflammation in overweight postmenopausal women

Increased inflammation and weight loss are associated with a reduction in bone mineral density (BMD). Aerobic exercise may minimize the loss of bone and weight loss may contribute to a decrease in cytokines. We tested the hypothesis that aerobic exercise in combination with a weight loss program would decrease circulating concentrations of inflammatory markers, thus mediating changes in BMD. This was a nonrandomized controlled trial. Eighty-six overweight and obese postmenopausal women (50-70 years of age; BMI, 25-40 kg/m(2)) participated in a weight loss (WL; n = 40) or weight loss plus walking (WL + AEX; n = 46) program. Outcome measures included BMD and bone mineral content of the femoral neck and lumbar spine measured by dual energy X-ray absorptiometry, interleukin-6, tumor necrosis factor-alpha, soluble receptors of IL-6, and TNF-alpha (sTNFR1 and sTNFR2; receptors in a subset of the population), VO(2) max, fat mass, and lean mass. Weight decreased in the WL (p < 0.001) and WL + AEX (p < 0.001) groups. VO(2) max increased (p < 0.001) after WL + AEX. There was a 2% increase in femoral neck BMD in the WL + AEX group (p = 0.001), which was significantly different from the WL group. The change in sTNFR1 was significantly associated with the change in femoral neck BMD (p < 0.05). The change in VO(2) max was an independent predictor of the change in femoral neck BMD. Our findings suggest that the addition of aerobic exercise is recommended to decrease inflammation and increase BMD during weight loss in overweight postmenopausal women.

Exercise and bone mineral density at the femoral neck in postmenopausal women: a meta-analysis of controlled clinical trials with individual patient data

OBJECTIVE

We conducted a meta-analysis using individual patient data to examine the efficacy of exercise for improving bone mineral density at the femoral neck in postmenopausal women.

STUDY DESIGN

Ten controlled clinical trials that included 595 subjects (aged 42-92 years) met our criteria for inclusion. Changes in femoral neck bone mineral density were examined by 2-way analysis of variance tests with repeated measures on 1 factor.

RESULTS

Across all designs and categories, there was an increase in bone mineral density of 0.73% +/- 5.52% and 0.45% +/- 6.78%, respectively, in the exercise and control subjects. However, comparison of initial and final bone mineral density values between exercise and control subjects revealed no statistically significant effect of exercise on femoral neck bone mineral density (P > .05).

CONCLUSION

Collectively, the exercise protocols that were used in this individual patient data meta-analysis do not improve femoral neck bone mineral density in postmenopausal women.

Physical activity in the prevention and amelioration of osteoporosis in women : interaction of mechanical, hormonal and dietary factors

Osteoporosis is a serious health problem that diminishes quality of life and levies a financial burden on those who fear and experience bone fractures. Physical activity as a way to prevent osteoporosis is based on evidence that it can regulate bone maintenance and stimulate bone formation including the accumulation of mineral, in addition to strengthening muscles, improving balance, and thus reducing the overall risk of falls and fractures. Currently, our understanding of how to use exercise effectively in the prevention of osteoporosis is incomplete. It is uncertain whether exercise will help accumulate more overall peak bone mass during childhood, adolescence and young adulthood. Also, the consistent effectiveness of exercise to increase bone mass, or at least arrest the loss of bone mass after menopause, is also in question. Within this framework, section 1 introduces mechanical characteristics of bones to assist the reader in understanding their responses to physical activity. Section 2 reviews hormonal, nutritional and mechanical factors necessary for the growth of bones in length, width and mineral content that produce peak bone mass in the course of childhood and adolescence using a large sample of healthy Caucasian girls and female adolescents for reference. Effectiveness of exercise is evaluated throughout using absolute changes in bone with the underlying assumption that useful exercise should produce changes that approximate or exceed the absolute magnitude of bone parameters in a healthy reference population. Physical activity increases growth in width and mineral content of bones in girls and adolescent females, particularly when it is initiated before puberty, carried out in volumes and at intensities seen in athletes, and accompanied by adequate caloric and calcium intakes. Similar increases are seen in young women following the termination of statural growth in response to athletic training, but not to more limited levels of physical activity characteristic of longitudinal training studies. After 9-12 months of regular exercise, young adult women often show very small benefits to bone health, possibly because of large subject attrition rates, inadequate exercise intensity, duration or frequency, or because at this stage of life accumulation of bone mass may be at its natural peak. The important influence of hormones as well as dietary and specific nutrient abundance on bone growth and health are emphasised, and premature bone loss associated with dietary restriction and estradiol withdrawal in exercise-induced amenorrhoea is described. In section 3, the same assessment is applied to the effects of physical activity in postmenopausal women. Studies of postmenopausal women are presented from the perspective of limitations of the capacity of the skeleton to adapt to mechanical stress of exercise due to altered hormonal status and inadequate intake of specific nutrients. After menopause, effectiveness of exercise to increase bone mineral depends heavily on adequate availability of dietary calcium. Relatively infrequent evidence that physical activity prevents bone loss or increases bone mineral after menopause may be a consequence of inadequate calcium availability or low intensity of exercise in training studies. Several studies with postmenopausal women show modest increases in bone mineral toward the norm seen in a healthy population in response to high-intensity training. Physical activities continue to stimulate increases in bone diameter throughout the lifespan. These exercise-stimulated increases in bone diameter diminish the risk of fractures by mechanically counteracting the thinning of bones and increases in bone porosity. Seven principles of bone adaptation to mechanical stress are reviewed in section 4 to suggest how exercise by human subjects could be made more effective. They posit that exercise should: (i) be dynamic, not static; (ii) exceed a threshold intensity; (iii) exceed a threshold strain frequency; (iv) be relatively brief but intermittent; (v) impose an unusual loading pattern on the bones; (vi) be supported by unlimited nutrient energy; and (vii) include adequate calcium and cholecalciferol (vitamin D3) availability.

Influence of Aquatic and Weight-Bearing Exercises on Quantitative Ultrasound Variables in Postmenopausal Women

OBJECTIVE

In this prospective, controlled study, the effects of weight bearing and aquatic exercises on the calcaneal ultrasonic scores of postmenopausal sedentary women was investigated.

DESIGN

A total of 62 postmenopausal sedentary women (mean age, 54.1 +/- 7 yrs) with broadband ultrasound attenuation (BUA) T-score variables less than -1 were admitted to Ataturk Balneotherapy and Rehabilitation Center and randomized into aquatic exercise (n = 21), weight-bearing exercise (n = 21), and control (n = 20) groups. The subjects were told to perform the aerobic exercises according to the Borg scale. Quantitative ultrasound variables, BUA, and speed of ultrasound were evaluated after the 6-mo training study.

RESULTS

Calcaneal BUA increased in aquatic exercise and weight-bearing exercise groups by 3.1% and 4.2% (P < 0.05, P < 0.05) respectively. There was a decrease in BUA by 1.3% in the control group (P > 0.05). Speed of ultrasound did not change in the aquatic exercise, weight-bearing exercise, or the control groups. There were no statistically significant differences between the exercise groups for BUA and speed of ultrasound. The percentage changes in the aquatic exercise and weight-bearing exercise groups were statistically significant when compared with the control group for BUA (P < 0.01, P < 0.01) and speed of ultrasound (P < 0.05, P < 0.05).

CONCLUSIONS

Although weight-bearing physical activity is known to be superior to non-weight-bearing activity to increase the bone mass, our present evidence shows that aquatic and weight-bearing exercises both can increase calcaneal BUA.

Evaluation of hormonal response and ultrasonic changes in the heel bone by aquatic exercise in sedentary postmenopausal women

OBJECTIVE

This study is based on whether moderate increased physical activity as aquatic exercise has anabolic effects on bone and evaluates this in terms of quantitative ultrasound and hormonal variables.

DESIGN

In this study, 41 postmenopausal sedentary women were admitted to Atatürk Balneotherapy and Rehabilitation Center, according to T scores of broadband ultrasound attenuation. Subjects were followed for 6 mos in aquatic exercise and control groups. The subjects were told to perform the aerobic exercises according to the Borg Scale. Ultrasonic and hormonal evaluation was done before and after the 6-mo training study.

RESULTS

In the exercise group, there were 36%, 75%, and 54% increases in the serum levels of insulin-like growth factor-1, growth hormone, and calcitonin, respectively. In addition, a 31% decrease was found in the serum levels of parathormone compared with the initial values. In the control group, serum levels of growth hormone decreased by 61%, but there were no statistically significant changes in the serum levels of insulin-like growth factor-1, calcitonin, or parathormone. T scores of broadband ultrasound attenuation and speed of sound increased by 19% and 63% in the exercise group, respectively, whereas there were decreases in the control group for the same variables. There were statistically significant differences between the control and the aquatic exercise groups for the 6-mo percentage of changes in broadband ultrasound attenuation and speed-of-sound T scores, insulin-like growth factor-1, growth hormone, parathormone, and calcitonin.

CONCLUSIONS

Aquatic exercise was determined to be effective to make an anabolic effect on the bone of the postmenopausal, sedentary subjects.

Daily physical movement and bone mineral density among a mixed racial cohort of women

PURPOSE

The impact of lifestyle physical activity on bone mineral density (BMD) is unclear. We examined the influence of physical activities typical of everyday life on BMD among 151 women (52.0 +/- 0.9 yr). These women were of low socioeconomic status, and 57.6% were Hispanic, 17.2% black, and 24.5% white.

METHODS

BMD was measured at the calcaneus by ultrasound with a Hologic Sahara sonometer. We measured physical activity with two questions from the Yale Physical Activity Survey that assessed h x d(-1) spent in motion typical of the past month and number of flights of stairs climbed up daily. Multivariate ANCOVA adjusted for adiposity and nutrients and medications known to influence BMD determined whether BMD differed between categories of physical activity (<2 vs > or = 2 flights x d(-1) and <7 vs > or = 7 h x d(-1)), menopausal status (pre- vs post-), and ethnic group (white vs nonwhite).

RESULTS

Among the premenopausal women (N = 63, 43.2+/-0.9 yr), adjusted mean calcaneal BMD and BMD T-score were similar between categories of stair climbing and accumulated daily movement regardless of ethnic origin (P > 0.05). Among the postmenopausal women (N = 88, 58.1 +/- 1.0 yr), adjusted mean calcaneal BMD (0.561 +/- 0.019 g x cm(-2) vs 0.503 +/- 0.016) (P = 0.022) and BMD T-score (-0.172 +/- 0.166 vs -0.695 +/- 0.143) (P = 0.020) were higher with more flights of stairs climbed daily in the Hispanic and black women only. Similarly, calcaneal BMD (0.579 +/- 0.023 g x cm(-2) vs 0.505 +/- 0.014) (P = 0.010) and BMD T-score (-0.020 +/- 0.209 vs -0.678 +/- 0.129) (P = 0.010) were higher with greater amounts of daily movement in only the older Hispanic and black women.

CONCLUSION

Lifestyle physical activity positively impacted BMD indicators in a mixed racial cohort of postmenopausal women. Older Hispanic and black women should be encouraged to engage in physical activities typical of everyday life to attenuate age-related bone loss.

Exercise and lumbar spine bone mineral density in postmenopausal women: a meta-analysis of individual patient data

BACKGROUND

Low bone mineral density (BMD) at the lumbar spine is a major public health problem among postmenopausal women. We conducted a meta-analysis of individual patient data (IPD) to examine the effects of exercise on lumbar spine BMD in postmenopausal women.

METHODS

IPD were requested from a previously developed database of summary means from randomized and nonrandomized trials dealing with the effects of exercise on BMD. Two-way analysis of variance tests with pairwise comparisons (p < or =.05) and 95% confidence intervals (CIs) were used to determine the statistical significance for changes in lumbar spine BMD.

RESULTS

Across 13 trials that included 699 subjects (355 exercise, 344 control), a statistically significant interaction was found between test and group (F = 15.232, p =.000). Pairwise comparisons (Bonferroni t tests) revealed a statistically significant increase in final minus initial BMD for the exercise group ( +/- SD = 0.005 +/- 0.043 g/cm(2), t = 2.46, p =.014, 95% CI = 0.001-0.009) and a statistically significant decrease in final minus initial BMD for the control group ( +/- SD = -0.007 +/- 0.045 g/cm(2), t = -3.051, p =.002, 95% CI = -0.012--0.002). Changes were equivalent to an approximate 2% benefit in lumbar spine BMD (exercise, +1%, control, -1%).

CONCLUSIONS

The results of this IPD meta-analysis suggest that exercise helps to improve and maintain lumbar spine BMD in postmenopausal women.

Dose-response of physical activity and low back pain, osteoarthritis, and osteoporosis

PURPOSE

The purpose of this study was to examine the evidence for causal relationships between physical activity (PA) and low back pain (LBP), osteoarthritis (OA), and osteoporosis (OP), and for dose-response relations involved.

METHODS

Computer database searches and personal retrieval systems were used to locate relevant literature.

RESULTS

PA can be effective in preventing LBP (Category A) but prolonged, heavy loading can lead to LBP (Category C). Specific exercises have not been found effective in treatment of acute LBP (Category A), but PA can be effective in chronic LBP (Category B), especially for diminishing the effects of deconditioning. No evidence indicates that PA directly prevents OA. Large amounts of intensive PA involving high impacts or torsional loadings or causing injuries increases risk of OA (Category C). Light or moderate PA does not increase the risk of OA (Category C). PA can be effective in the treatment and rehabilitation of OA (Category B). High-intensity loading is osteogenic and possibly useful in prevention of OP (Category A) at the loaded site, but low to moderate loading is not osteogenic (Category D). Static efforts and slow movements are ineffective or less effective than fast application of force (Category B). The types of PA to attain the effects mentioned above are known except in the case of prevention of LBP, but dose-response relationships are poorly known; at best, semiquantitatively on the basis of just a few studies.

CONCLUSION

Given the shown primary and/or secondary preventative effectiveness of PA regarding LBP, OA, and OP, research to elucidate the inadequately known dose-response relations should be given high priority.

Strength training in the elderly: effects on risk factors for age-related diseases

Strength training (ST) is considered a promising intervention for reversing the loss of muscle function and the deterioration of muscle structure that is associated with advanced age. This reversal is thought to result in improvements in functional abilities and health status in the elderly by increasing muscle mass, strength and power and by increasing bone mineral density (BMD). In the past couple of decades, many studies have examined the effects of ST on risk factors for age-related diseases or disabilities. Collectively, these studies indicate that ST in the elderly: (i) is an effective intervention against sarcopenia because it produces substantial increases in the strength, mass, power and quality of skeletal muscle; (ii) can increase endurance performance; (iii) normalises blood pressure in those with high normal values; (iv) reduces insulin resistance; (v) decreases both total and intra-abdominal fat; (vi) increases resting metabolic rate in older men; (vii) prevents the loss of BMD with age; (viii) reduces risk factors for falls; and (ix) may reduce pain and improve function in those with osteoarthritis in the knee region. However, contrary to popular belief, ST does not increase maximal oxygen uptake beyond normal variations, improve lipoprotein or lipid profiles, or improve flexibility in the elderly.

Alternative therapies for menopause

If a woman does not want to use, or cannot use, hormone replacement therapy, then she must consider other ways to address two issues related to menopause: reducing her risk of developing cardiovascular disease, osteoporosis, and other health problems that increase as women age, and symptomatology. Risk reduction of an array of health problems can be achieved through diet, exercise, and stress management. The nutraceuticals of specific vitamins, minerals, phytoestrogens, and essential fatty acid supplementations are a vital component of the risk reduction health program. Risk reduction of osteoporosis can be enhanced specifically through the use of ipriflavone and a comprehensive "bone building" vitamin and mineral program. Control of homocysteine levels for prevention of CAD, osteoporosis, and other health problems can be accomplished through B vitamin supplementation. The same interventions for risk reduction also may prove to be effective in prevention and treatment of menopausal-related symptoms, particularly when the B vitamins, magnesium, isoflavones, and essential fatty acids are used. If lifestyle interventions and nutraceuticals do not adequately address symptomatology, however, a woman has several alternative therapies from which to choose. There are numerous excellent multiherbal and homeopathic therapies that can be purchased over the counter. A woman also can choose to be evaluated by an alternative therapy practitioner and have a program designed specifically for her health needs. Although there has been limited clinical research of herbal and homeopathic alternative therapies for the menopause, when taken according to directions and if no contraindications exist, they have the potential for being extremely effective and safe options.

Esporte como prevenção de osteoporose: um estudo da massa óssea de mulheres pós-menopáusicas que foram atletas de voleibol

Para examinar se o voleibol exerce efeito positivo na massa óssea de mulheres pós-menopáusicas, mediu-se a densidade mineral óssea (DMO), usando absorção de dupla energia de raios X (DEXA) na coluna lombar (L1, L2, L3, L4 e L2-L4) e no fêmur proximal (colo, trocanter, intertrocantérica, total e triângulo de Ward) em dois grupos de mulheres saudáveis, brasileiras e brancas. Um grupo constituiu-se de 21 atletas veteranas, que jogaram voleibol competitivamente na 2ª década de vida e continuaram jogando pelo menos nos últimos 12 meses. O grupo controle consistiu de 21 mulheres que nunca foram atletas. Os grupos foram similares na idade, índice de massa corporal, tempo de menopausa e reposição hormonal. O grupo de atletas apresentou DMO significativamente superior na coluna lombar e em todas as regiões do fêmur proximal, conforme alguns valores em g/cm² (média ± dp) da tabela a seguir: Esses resultados indicam que a prática do voleibol contribui na manutenção da massa óssea de mulheres pós-menopáusicas e conseqüente prevenção de osteoporose, incluindo as regiões que são mais suscetíveis a fraturas.

Aerobic exercise and bone density at the hip in postmenopausal women: a meta-analysis

BACKGROUND

The effects of aerobic exercise on bone density at the hip in postmenopausal women in the absence of estrogen replacement therapy are not currently known. The purpose of this study was to examine the effects of aerobic exercise on bone density at the hip in postmenopausal women.

METHODS

Using the meta-analytic approach, studies dealing with the effects of aerobic exercise on bone density at the hip in postmenopausal women were searched for using computerized literature searches (MEDLINE, January 1978 to December 1995) as well as cross-referencing from retrieved review articles and original investigations.

RESULTS

A total of 18 effect sizes were derived from six studies. Using a fixed-effects model and bootstrap resampling (5,000 iterations) overall changes in bone density at the hip yielded an average effect size of 0.43 (95% CI = 0.04 to 0.81), equivalent to an overall change of approximately 2.42% (exercise = 2.13%; nonexercise = -0.29%). Statistically significant differences were observed when effect sizes were partitioned by country in which studies were conducted (United States, mean = 1.03, 95% CI = 0.48 to 1.68; other countries, mean = 0.18, 95% CI = -0.27 to 0.54; Qb = 5.44, P = 0.04) and calcium intake (> or =1,000 mg/day, mean = 0.83, 95% CI = 0.49 to 1.23; <1,000 mg/day = -0.23, 95% CI = -0.85 to 0.21; Qb = 10.64, P = 0.002).

CONCLUSIONS

The overall results of this study suggest that site-specific aerobic exercise has a moderately positive effect on bone density at the hip in postmenopausal women. However, a need exists for additional, well-designed studies before a final recommendation can be made regarding the efficacy of aerobic exercise as a nonpharmacologic intervention for optimizing bone density at the hip in postmenopausal women.

Musculoskeletal challenges of osteoporosis

Reduction in the biomechanical competence of the axial skeleton can result in challenging complications. Osteoporosis consists of a heterogeneous group of syndromes in which bone mass per unit volume is reduced in otherwise normal bone, which results in more fragile bone. The geriatric population has an increased risk for debilitating postural changes because of several factors. The two most apparent factors are involutional loss of functional muscle motor units and the greater prevalence of osteoporosis in this population. Obviously, the main objective of rehabilitation is to prevent fractures rather than to treat the complications. These complications can vary from "silent" compression fractures of vertebral bodies, to sacral insufficiency fractures, to "breath-taking" fractures of the spine or femoral neck. The exponential loss of bone at the postmenopausal stage is not accompanied by an incremental loss of muscle strength. The loss of muscle strength follows a more gradual course and is not affected significantly by a sudden hormonal decline, as is the case with bone loss. This muscle loss may contribute to osteoporosis-related skeletal disfigurations. In men and women, the combination of aging and reduction of physical activity can affect musculoskeletal health, and contribute to the development of bone fragility. The parallel decline in muscle mass and bone mass with age is more than a coincidence, and inactivity may explain some of the bone loss previously associated with aging per se. Kyphotic postural change is the most physically disfiguring and psychologically damaging effect of osteoporosis and can contribute to an increment in vertebral fractures and the risk of falling. Axial skeletal fractures, such as fracture of the sacral alae (sacral insufficiency fracture) and pubic rami, may not be found until radiographic changes are detected. Management of chronic pain should include not only improvement of muscle strength and posture but also, at times, reduction of weight bearing on the painful pelvis with insufficiency fractures. Axial skeletal health can be assisted with improvement of muscular supportive strength. Disproportionate weakness in the back extensor musculature relative to body weight or flexor strength considerably increases the risk of compressing porous vertebrae. A proper exercise program, especially osteogenic exercises, can improve musculoskeletal health in osteoporotic patients. Exercise not only improves musculoskeletal health but also can reduce the chronic pain syndrome and decrease depression. Application of a proper back support can decrease kyphotic posturing and can expedite the patient's return to ambulatory activities. Measures that can increase safety during ambulatory activities can reduce risk of falls and fractures. Managing the musculoskeletal challenges of osteoporosis goes hand in hand with managing the psychological aspects of the disease.

Aerobic exercise and lumbar spine bone mineral density in postmenopausal women: a meta-analysis

PURPOSE

To use the meta-analytic approach to examine the effects of aerobic exercise on lumbar spine bone mineral density in postmenopausal women.

DATA SOURCES

Studies were retrieved from computer searches (MEDLINE, Current Contents) as well as cross-referencing from the bibliographies of retrieved studies and review articles.

STUDY SELECTION

A total of 17 effect sizes consisting of 330 subjects (192 exercise, 138 nonexercise) were included from the 10 studies that met the criteria for inclusion: (1) aerobic activity as the only exercise intervention, (2) postmenopausal women as subjects, (3) comparative nonexercise group included, (4) changes in lumbar spine bone mineral density reported, (5) studies published in English-language journals between January 1975 and December 1994.

DATA EXTRACTION

The primary outcome measure of interest was the treatment effect delta3, defined as the percent change in lumbar spine bone mineral density, calculated by subtracting the percent change in the exercise group from the percent change in the nonexercise group.

RESULTS

Using a fixed effects model, bootstrap analysis (10,000 replications) showed that significant changes in lumbar spine bone mineral density occurred (mean +/- SD = 2.83 +/- 0.77%, 95% confidence interval (CI) = 1.33 to 4.35%). This overall average increase was caused primarily by the loss of lumbar spine bone mineral density in the nonexercise group relative to the exercise group (mean +/- SD, exercise = .32 +/- 2.46%, 95% CI = -0.94 to 1.58; nonexercise = -2.51 +/- 2.69%, 95% CI = -4.60 to -0.96).

CONCLUSION

The results of this meta-analysis suggest that aerobic exercise helps to maintain lumbar spine bone mineral density in postmenopausal women.

Meta-analysis of the effectiveness of physical activity for the prevention of bone loss in postmenopausal women

A meta-analysis was done to measure the effect of physical activity on the bone mass of healthy postmenopausal women. All studies published between 1966 and 1996, in French or English, were reviewed for inclusion from Medline search, bibliographies of relevant studies, review articles and books. Studies had to be prospective intervention trials, randomized or not, evaluating the effectiveness of an exercise program of any duration, frequency and intensity, with a control group. Studies had to measure bone parameters and involve healthy postmenopausal women over 50 years of age who were free of symptomatic osteoporosis at the time of study entry. Effect sizes (ES) were calculated for each bone parameter and site measured in every eligible study according to Hedges and Olkin. DerSimonian and Laird's model was used to estimate overall effect sizes when combining studies. All analyses were bone parameter and site specific. Of 217 papers extracted from the literature, 187 did not meet eligibility criteria and 12 others were rejected. The two main reasons for rejection were that both genders were combined in the analyses and no exercise group without drug interaction was present. Eighteen studies were included for meta-analysis. Taking into account the frequency, duration, compliance rate and average age of the subjects, the programs were judged of moderate intensity and focused on walking, running, physical conditioning and aerobics. A significant effect of physical activity was detected on the bone mineral density at the L2-4 level of the lumbar column in studies published after 1991 (ES = 0.8745, p < 0.05). No effect could be seen, however, on forearm and femoral bone mass. Although applied to a small number of studies, this meta-analysis suggests that exercise programs in a population of postmenopausal women over 50 years of age are effective for preventing spinal bone mineral density loss at the L2-4 level. However, such programs do not have any effect on the forearm or femoral bone mass.

Evidence for an interaction between calcium intake and physical activity on changes in bone mineral density

Results of trials on the effects of physical activity on bone mineral density (BMD) are conflicting. The current hypothesis was that calcium intake modifies the bone response to physical activity. Published trials on physical activity and bone density were reviewed, and the results of 17 trials are summarized. Physical activity has beneficial effects on BMD at high calcium intakes, with no effect at mean calcium intakes less than a mean of 1000 mg/day. The modifying effect of calcium intake on BMD among exercise groups is more pronounced in the lumbar spine than in the radius. This analysis may explain conflicting results of trials on physical activity and calcium effects on bone. Controlled trials designed to test adequately this hypothesis are needed.

The effect of weight-bearing exercise on bone mineral density: a study of female ex-elite athletes and the general population

The aim of this retrospective cohort study was to estimate the changes in bone mineral density (BMD) as a consequence of exercise in female ex-athletes and age-matched controls. Eighty-three ex-elite female athletes (67 middle and long distance runners, 16 tennis players, currently aged 40-65) were recruited from the original records of their sporting associations. Controls were 585 age-matched females. The main outcome measures were BMD of lumbar spine (LS), femoral neck (FN), and forearm, estimated by dual-energy X-ray absorptiometry (DXA) scan. Levels of physical activity were assessed using a modified Allied Dunbar Fitness Survey scale and classified as (a) ex-athletes, (b) active controls (> or = 1 h of vigorous physical activity currently and in the past), (c) low activity controls with inconsistent or intermediate levels of activity, and (d) inactive controls (< 15 minutes of exercise per week). After adjustment for differences in age, weight, height, and smoking, athletes had greater BMDs than controls: 8.7% at the LS (95% confidence interval [CI] 5.4-12.0; p < 0.001) and 12.1% at FN (CI 9.0-15.3; p < 0.001). The benefits of exercise appeared to persist after cessation of sporting activity. Active controls (n = 22) had greater BMDs than the inactive group (n = 347): 7.9% LS (CI 2.0-13.8; p = 0.009) and 8.3% FN (CI 2.7-13.8; p = 0.004). The low activity controls (n = 216) had an intermediate BMD. Tennis players had greater BMDs compared with runners: 12.0% LS (CI 5.7-18.2; p = 0.0004) and 6.5% FN (CI -0.2-13.2; p = 0.066). The BMD of tennis players' dominant forearms were greater than their nondominant forearms. In conclusion, regular vigorous weight-bearing exercise of 1 h or more per week is associated with an increase in BMD within a normal population. This study confirms long-term weight-bearing exercise as an important factor in the regulation of bone mass and fracture prevention.

Effect of exercise training programme on bone mineral density in novice college rowers

Exercise has important effects on skeletal mineralization. Changes in bone mineral density (BMD) and bone mineral content (BMC) as measured by dual energy X-ray absorptiometry were investigated in a group of 17 male novice college oarsmen over a 7-month period and were compared with eight age-matched controls. The rowing training programme consisted of approximately 8 h rowing, 1 h weight training, and 1 h running per week. After 7 months training the mean BMD of the lumbar spine (L1-L4) had increased significantly by 2.9% (P < 0.001) and the mean BMC had increased by 4.2% (P < 0.001). There was no significant change in the control group. Neither group showed a significant change in BMD or BMC in the femoral neck, greater trochanter or Ward's triangle. This study provides further evidence that exercise plays an important role in bone mineral formation.

Exercise considerations for postmenopausal women with osteoporosis

Individuals with osteoporosis are at an increased risk of fracture due to a net loss of bone mass. The cellular mechanisms causing decreased bone mass are increased osteoclast-mediated bone resorption and/or decreased osteoblast-mediated bone formation. Clinical studies have shown that bone loss can be prevented by estrogen replacement therapy and calcium supplementation. Weight-bearing and strengthening exercise may also play a role in retarding bone loss in the postmenopausal woman, and it may even increase bone mass. The essential components of an exercise program include intensity, duration, frequency, and type of activity. Additional goals of a therapeutic exercise program are to improve flexibility and balance, and to prevent falls. Structure-function relationships in normal and osteoporotic bone and the effects of exercise on bone are reviewed. A rational approach for exercise strategies is discussed.