Effects of Oestrogen Treatment on Skeletal Response to Exercise in the Hips and Spine in Postmenopausal Women: A Meta-Analysis

Treatment Effects in Randomized and Nonrandomized Studies of Pharmacological Interventions: A Meta-Analysis

Importance

Randomized clinical trials (RCTs) are widely regarded as the methodological benchmark for assessing clinical efficacy and safety of health interventions. There is growing interest in using nonrandomized studies to assess efficacy and safety of new drugs.

Objective

To determine how treatment effects for the same drug compare when evaluated in nonrandomized vs randomized studies.

Data Sources

Meta-analyses published between 2009 and 2018 were identified in MEDLINE via PubMed and the Cochrane Database of Systematic Reviews. Data analysis was conducted from October 2019 to July 2024.

Study Selection

Meta-analyses of pharmacological interventions were eligible for inclusion if both randomized and nonrandomized studies contributed to a single meta-analytic estimate.

Data Extraction and Synthesis

For this meta-analysis using a meta-epidemiological framework, separate summary effect size estimates were calculated for nonrandomized and randomized studies within each meta-analysis using a random-effects model and then these estimates were compared. The reporting of this study followed the Guidelines for Reporting Meta-Epidemiological Methodology Research and relevant portions of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guideline.

Main Outcome and Measures

The primary outcome was discrepancies in treatment effects obtained from nonrandomized and randomized studies, as measured by the proportion of meta-analyses where the 2 study types disagreed about the direction or magnitude of effect, disagreed beyond chance about the effect size estimate, and the summary ratio of odds ratios (ROR) obtained from nonrandomized vs randomized studies combined across all meta-analyses.

Results

A total of 346 meta-analyses with 2746 studies were included. Statistical conclusions about drug benefits and harms were different for 130 of 346 meta-analyses (37.6%) when focusing solely on either nonrandomized or randomized studies. Disagreements were beyond chance for 54 meta-analyses (15.6%). Across all meta-analyses, there was no strong evidence of consistent differences in treatment effects obtained from nonrandomized vs randomized studies (summary ROR, 0.95; 95% credible interval [CrI], 0.89-1.02). Compared with experimental nonrandomized studies, randomized studies produced on average a 19% smaller treatment effect (ROR, 0.81; 95% CrI, 0.68-0.97). There was increased heterogeneity in effect size estimates obtained from nonrandomized compared with randomized studies.

Conclusions and Relevance

In this meta-analysis of treatment effects of pharmacological interventions obtained from randomized and nonrandomized studies, there was no overall difference in effect size estimates between study types on average, but nonrandomized studies both overestimated and underestimated treatment effects observed in randomized studies and introduced additional uncertainty. These findings suggest that relying on nonrandomized studies as substitutes for RCTs may introduce additional uncertainty about the therapeutic effects of new drugs.

Effects of Hormone Therapy and Exercise on Bone Mineral Density in Healthy Women-A Systematic Review and Meta-analysis

CONTEXT

There is some evidence that an adequate "anabolic hormonal milieu" is essential for the mechanosensitivity/transduction/response of bone tissue.

OBJECTIVE

This work aimed to determine whether enhancing hormone therapy (HT) with exercise increases the isolated effect of HT on bone mineral density (BMD) at the lumbar spine (LS) and femoral neck (FN).

METHODS

A comprehensive search of 6 electronic databases according to the PRISMA statement up to April 28, 2021, included controlled trials longer than 6 months with 3 study arms: (a) HT, (b) exercise, and (c) HT plus exercise (HT + E). Apart from HT, no pharmaceutic therapy or diseases with relevant osteoanabolic or osteocatabolic effect on bone metabolism were included. The present analysis was conducted as a random-effects meta-analysis. Outcome measures were standardized mean differences (SMD) for BMD changes at the LS and FN.

RESULTS

Our search identified 6 eligible studies (n = 585). Although the effect of HT + E was more pronounced in the LS (SMD: 0.19; 95% C,: -0.15 to 0.53) and FN-BMD (0.18; -0.09 to 0.44) compared to the HT group, we did not observe significant differences between the 2 groups. We observed a low (I2: 29%) or moderate (I2: 49%) level of heterogeneity between the trials for FN or LS.

CONCLUSION

We do not observe a significant effect of HT + E vs HT alone. We largely attribute this result to varying HT supplementation and hormonal status. Bearing in mind that synergistic/additive effects between HT and mechanical stimulation can only be expected in situations of hormonal insufficiency, further clinical studies should consider baseline endogenous estrogen production but also HT dosing more carefully.

An Up-Date of the Muscle Strengthening Exercise Effectiveness in Postmenopausal Women with Osteoporosis: A Qualitative Systematic Review

BACKGROUND

Osteoporosis (OP) is a systemic disease that is characterized by decreased bone density and quality. Purpose: The purpose of this systematic review was to determine the effects of muscle strengthening exercise in postmenopausal women with OP. Methods: A literature search was conducted systematically in MEDLINE, CINAHL, EMBASE databases for human studies up to 31 March 2021. Two researchers screened the articles against predefined inclusion criteria; a third resolved discrepancies. Articles were included if they assessed the effects of muscle strengthening exercise in postmenopausal women with OP. The protocol for this systematic review was registered on PROSPERO (CRD42021207917) and a qualitative systematic review was carried out following the PRISMA statement. Methodological quality was evaluated through the scientific validity scales PEDro. Finally, RTCs and NRCTs risk of bias was assessed with the Cochrane risk of bias tool (Risk of Bias-ROB 2.0) and ROBINS-1, respectively. Results: A total of 16 studies (1028 subjects) that met the different eligibility criteria previously established were selected. There is evidence of good methodological quality and a low to moderate risk of bias that supports that muscle strengthening exercise alone or in combination with other therapeutic modalities improves BMD (9, n = 401) in proximal femur and lumbar vertebra body, muscle strength (10, n = 558), balance (4, n = 159), functionality (7, n = 617), and quality of life (5, n = 291).

CONCLUSIONS

Exercise programs focused on muscle strengthening have benefits for all variables studied in postmenopausal women with OP.

Change in Quantitative Ultrasound-assessed Speed of Sound as a Function of Age in Women and Men and Association With the Use of Antiresorptive Agents: The Canadian Multicentre Osteoporosis Study

INTRODUCTION

Five-year changes in multisite quantitative ultrasound-assessed speed of sound (SOS in m/s) were studied in a cohort of women and men. The impacts of antiresorptive therapies and menopausal status on SOS were also assessed.

METHODOLOGY

Two SOS assessments, clinical assessments, and comprehensive questionnaires were completed 5 years apart on 509 women and 211 men. Age at first assessment was grouped into: <40 yr, 40-49 yr, 50-59 yr, 60-69 yr, 70-79 yr and 80+ yr. Mean rate of change in SOS at the distal radius and tibia were calculated for each age grouping by sex. SOS changes were stratified by antiresorptive use (yes, no) or menopausal status (premenopausal, postmenopausal, or bilateral oophorectomy).

RESULTS

Mean losses in SOS occurred over the 5 years in almost all age groupings. In women, mean losses in SOS for the <40 yr, 40-49 yr, 50-59 yr, 60-69 yr, 70-79 yr, and 80+ yr age groupings were -59, -83, -107, -92, -80 and -66 (p = 0.30; differences among age groupings) at the radius and -18, -16, -54, -1, -9 and 31 at the tibia (p < 0.05), respectively. In men, mean SOS losses were -101, -56, -69, -67, -83 and -127 at the radius (p = 0.61) and -46, -61, 0, -35, -29, and -26 at the tibia (p = 0.23). At the tibia, women prescribed antiresorptives had a mean increase in SOS (8.6 m/s) whereas untreated participants had a mean loss (-23.0; p < 0.001); there was no significant impact at the distal radius. There were no significant differences in change in SOS among menopausal groups (p > 0.26).

CONCLUSIONS

Mean SOS generally declined over 5 years in all age groupings of both sexes. The consistent mean losses in SOS over the age spans investigated are coincident with increasing fracture risk. Women on antiresorptive therapy had increased mean SOS over the 5-year assessment period at the tibia, whereas untreated women had mean losses in SOS.

Skeletal effects of plyometric exercise and metformin in ovariectomized rats

Estrogen deficiency causes bone loss and skeletal muscle dysfunction, and attenuates the musculoskeletal effects of exercise. The anti-diabetic drug metformin has been suggested to promote beneficial skeletal effects. To explore whether metformin can improve musculoskeletal training response during estrogen deficiency, we investigated the skeletal effects of plyometric exercise and metformin, in an ovarectomized (OVX) rat model of osteoporosis. Female Sprague Dawley rats, 12 weeks of age, rats were allocated to a sham-operated group (Sham), and four OVX groups; metformin (OVX-Met), exercise (OVX-Ex), combined metformin and exercise (OVX-MetEx) and a control group (OVX-Ctr), n = 12/group. Dual X-ray absorptiometry, micro computed tomography, fracture toughness testing, histomorphometry and plasma analyses were performed to explore skeletal effects. All intervention groups exhibited a higher gain in femoral bone mineral density (BMD) than OVX-Ctr (p < .01). The combined intervention also resulted in a higher gain in femoral and spine BMD compared to OVX-Met (p < .01). Both exercise groups displayed improved microarchitecture, including both cortical and trabecular parameters (p < .05). This was most evident in the OVX-MetEx group where several indices were at sham level or superior to OVX-Ctr (p < .05). The OVX-MetEx group also exhibited an enhanced toughening effect compared to the other OVX groups (p < .05). The beneficial skeletal effects seemed to be mediated by inhibition of bone resorption and stimulation of bone formation. The training response (i.e. jumping height) was also greater in the metformin treated rats compared to OVX-Ex (p < .01), indicating a performance-enhancing effect of metformin. Both exercise groups displayed higher lean mass than OVX-Ctr (p < .05). In conclusion, the combination of plyometric exercise and metformin improved trabecular microarchitecture and bone material properties relative to OVX controls. However, no additive effect of the combined intervention was observed compared to exercise alone.

Effects of physical activity on bone mineral density in older adults: Korea National Health and Nutrition Examination Survey, 2008-2011

We compared the relationship between physical activity (PA) and bone mineral density (BMD) in men and women aged over 50 years. Only moderate-to-vigorous PA was positively associated with hip BMD in men. There was no association between PA and BMD at any site in women.

INTRODUCTION

Physical activity (PA) is widely recommended for osteoporosis. However, epidemiological data regarding the intensity or volume of PA required for bone health are lacking. We aimed to investigate and compare the relationship between PA and bone mineral density (BMD) in men and women.

METHODS

This population-based cross-sectional study used data from the 4th and 5th Korea National Health and Nutrition Examination Surveys and included 2767 men and 2753 women aged > 50 years. The intensity, frequency, and duration of PA were assessed using a questionnaire, and the participants were divided into the no activity, walking-only, moderate PA, and vigorous PA groups. BMD was measured at the lumbar spine (LS), femur neck (FN), and total hip (TH) using dual-energy X-ray absorptiometry.

RESULTS

Adjusted-BMDs of the hip were higher in men and women in the moderate and vigorous PA groups than those in men and women in the walking-only and no activity groups, while frequency and duration of PA were not associated with BMD at any site. The odds ratios for osteoporosis were the lowest at the FN and TH in men in the vigorous PA group (0.354, 95% confidence interval (CI) 0.139-0.901, P < 0.002, and 0.072, 95% CI 0.007-0.766, P < 0.003, respectively), while it was not significant in women.

CONCLUSION

Only moderate-to-vigorous PA was positively associated with the hip BMD in men. There was no association between PA and BMD at any site in women. It is necessary to assess the PA intensity for bone health based on the site and sex.

Effect of Estrogen on Musculoskeletal Performance and Injury Risk

Estrogen has a dramatic effect on musculoskeletal function. Beyond the known relationship between estrogen and bone, it directly affects the structure and function of other musculoskeletal tissues such as muscle, tendon, and ligament. In these other musculoskeletal tissues, estrogen improves muscle mass and strength, and increases the collagen content of connective tissues. However, unlike bone and muscle where estrogen improves function, in tendons and ligaments estrogen decreases stiffness, and this directly affects performance and injury rates. High estrogen levels can decrease power and performance and make women more prone for catastrophic ligament injury. The goal of the current work is to review the research that forms the basis of our understanding how estrogen affects muscle, tendon, and ligament and how hormonal manipulation can be used to optimize performance and promote female participation in an active lifestyle at any age.

Exercise for the prevention of osteoporosis in postmenopausal women: an evidence-based guide to the optimal prescription

BACKGROUND

Osteoporosis and related fragility fractures are a global public health problem in which pharmaceutical agents targeting bone mineral density (BMD) are the first line of treatment. However, pharmaceuticals have no effect on improving other key fracture risk factors, including low muscle strength, power and functional capacity, all of which are associated with an increased risk for falls and fracture, independent of BMD. Targeted exercise training is the only strategy that can simultaneously improve multiple skeletal and fall-related risk factors, but it must be appropriately prescribed and tailored to the desired outcome(s) and the specified target group.

OBJECTIVES

In this review, we provide an overview of the general principles of training and specific loading characteristics underlying current exercise guidelines for the prevention of osteoporosis, and an update on the latest scientific evidence with regard to the type and dose of exercise shown to positively influence bone mass, structure and strength and reduce fracture risk in postmenopausal women.

Emerging evidence on the link between depressive symptoms and bone loss in postmenopausal women

Osteoporosis and depression are major health problems of crisis proportions in postmenopausal women. Researchers have established a relationship between bone loss and depression, although few studies have focused on postmenopausal women. The purposes of this integrative review were to synthesize and summarize the available literature on: 1) the associations between bone loss and depression in postmenopausal women; and 2) potential variables that impact the associations between bone loss and depression in postmenopausal women. After searching the databases PubMed, CINAHL, Embase, and the Cochrane library between 2007 and 2017, 12 articles met the inclusion criteria. The majority of the included studies supported the relationship between depression and bone loss in postmenopausal women, although little information is offered as to why this relationship exists. This review summarizes the research that has been completed on depression and bone loss in postmenopausal women and identifies gaps in the literature. These findings will aid in the planning of future research and the development of health care recommendations.

Mouse models to evaluate the role of estrogen receptor α in skeletal maintenance and adaptation

Estrogen signaling and mechanical loading have individual and combined effects on skeletal maintenance and adaptation. Previous work investigating estrogen signaling both in vitro and in vivo using global estrogen receptor α (ERα) gene knockout mouse models has provided information regarding the role of ERα in regulating bone mass and adaptation to mechanical stimulation. However, these models have inherent limitations that confound interpretation of the data. Therefore, recent studies have focused on mice with targeted deletion of ERα from specific bone cells and their precursors. Cell stage, tissue type, and mouse sex all influence the effects of ERα gene deletion. Lack of ERα in osteoblast progenitor and precursor cells generally affects the periosteum of female and male mice. The absence of ERα in differentiated osteoblasts, osteocytes, and osteoclasts in mice generally resulted in reduced cancellous bone mass, with differing reports of the effect by animal sex and greater deficiencies in bone mass typically occurring in cancellous bone in female mice. Limited data exist for the role of bone cell-specific ERα in skeletal adaptation in vivo. Cell-specific ERα gene knockout mice provide an excellent platform for investigating the function of ERα in regulating skeletal phenotype and response to mechanical loading by sex and age.

Adaptations with Intermittent Exercise Training in Post- and Premenopausal Women

INTRODUCTION

The purposes of the present study was to examine the effect of intermittent exercise training on musculoskeletal and metabolic health in postmenopausal (PM) and premenopausal (PRM) women and, furthermore, to evaluate whether the adaptations can be maintained with a reduced training frequency.

METHODS

Eighteen PM (51 ± 1 yr, mean ± SEM) and 12 PRM (48 ± 1 yr) women participated in floorball training approximately two times per week for 12 wk. In a subgroup (n = 9) of PM women (PM40), exercise training was performed for an additional 40 wk with a reduced training frequency of approximately one training session per week.

RESULTS

In PM, the body fat percentage decreased (P < 0.05) and the total lean leg mass increased (P < 0.05) during the 12-wk training period, with no changes in PRM. In both PM and PRM, lean body mass and maximal oxygen uptake (V˙O2max) were higher, and Yo-Yo intermittent endurance test 1 (YYIET-1) performance was better (P < 0.05) after the 12-wk training period. Procollagen type 1 amino-terminal propeptide was higher (P < 0.05) in PM, and total leg bone mineral density (BMD) was higher (P < 0.05) in both PM and PRM after the 12-wk training period. In PM40, total lean leg mass, V˙O2max, YYIET-1 performance, level of procollagen type 1 amino-terminal propeptide, and total leg BMD were maintained, whereas whole-body BMD and glycated hemoglobin (HbA1c) were reduced (P < 0.05) and the expression of muscle glucose transporter type 4 was higher (P < 0.05).

CONCLUSION

Twelve weeks of intermittent exercise training increased BMD, intermittent exercise capacity, and V˙O2max in PM and PRM, with PM also having positive changes in body composition. Additional 40 wk of training with a reduced frequency was sufficient to preserve these physiological adaptations and also improve blood glucose regulation in PM.

The Effectiveness of Combined Exercise Interventions for Preventing Postmenopausal Bone Loss: A Systematic Review and Meta-analysis

Study Design Systematic review and meta-analysis. Background It remains unclear whether exercise combining different types of physical activities (combined exercise interventions) would effectively preserve postmenopausal women's bone mineral density (BMD) at different sites. Objective To examine the impact of combined exercise interventions on lumbar spine, femoral neck, total hip, and total body BMD in postmenopausal women. Methods An electronic database search was conducted in PubMed, EMBASE, SPORTDiscus, and Web of Science up to January 1, 2016. Randomized controlled trials that conducted combined exercise interventions and reported BMD values in postmenopausal women were included. Two authors independently extracted the data from individual studies. The primary end point was the change in BMD values from baseline to follow-up. The effect sizes were estimated by the standardized mean difference (SMD) methods using fixed-effects models. Results Eleven randomized controlled trials including 1061 postmenopausal women met the inclusion criteria. The levels of between-study heterogeneity were relatively low (I²<50%). Exercise integrating different physical activities significantly increased lumbar spine (SMD, 0.170; 95% confidence interval [CI]: 0.027, 0.313; P = .019), femoral neck (SMD, 0.177; 95% CI: 0.030, 0.324; P = .018), total hip (SMD, 0.198; 95% CI: 0.037, 0.359; P = .016), and total body (SMD, 0.257; 95% CI: 0.053, 0.461; P = .014) BMD. Combined exercise interventions generated a beneficial effect on femoral neck BMD (SMD, 0.219; 95% CI: 0.034, 0.404; P = .020) in groups with women aged younger than 60 years, and significantly improved lumbar spine BMD (SMD, 0.349; 95% CI: 0.064, 0.634; P = .016) in groups with women aged 60 years or older. Conclusion Our findings suggest that combined exercise interventions appear to be effective in preserving postmenopausal women's BMD at the lumbar spine, femoral neck, total hip, and total body. Level of Evidence Therapy, level 1a. J Orthop Sports Phys Ther 2017;47(4):241-251. Epub 3 Mar 2017. doi:10.2519/jospt.2017.6969.