Obesity, health-care utilization, and health-related quality of life after fracture in postmenopausal women: Global Longitudinal Study of Osteoporosis in Women (GLOW)

Ectopic fat in muscle and poor glycemic control are negatively associated with trabecular bone score in type 2 diabetes

INTRODUCTION

Type 2 Diabetes (T2D) is associated with fractures, despite preserved Bone Mineral Density (BMD). This study aimed to evaluate the relationship between BMD and trabecular bone score (TBS) with the reallocation of fat within muscle in individuals with eutrophy, obesity, and T2D.

METHODS

The subjects were divided into three groups: eutrophic controls paired by age and sex with the T2D group (n = 23), controls diagnosed with obesity paired by age, sex, and body mass index with the T2D group (n = 27), and the T2D group (n = 29). BMD and body fat percentage were determined using dual-energy X-Ray absorptiometry. TBS was determined using TBS iNsight software. Intra and extramyocellular lipids in the soleus were measured using proton magnetic resonance spectroscopy.

RESULTS

TBS was lower in the T2D group than in the other two groups. Glycated hemoglobin (A1c) was negatively associated with TBS. Body fat percentage was negatively associated with TBS and Total Hip (TH) BMD. TH BMD was positively associated with intramuscular lipids. A trend of negative association was observed between intramuscular lipids and TBS.

CONCLUSION

This study showed for the first time that the reallocation of lipids within muscle has a negative association with TBS. Moreover, these results are consistent with previous studies showing a negative association between a parameter related to insulin resistance (intramuscular lipids) and TBS.

Lipid Peroxidation as a Possible Factor Affecting Bone Resorption in Obese Subjects-Preliminary Research

Oxidative stress, which promotes bone catabolism, also affects the quality of bone tissue. We aimed to assess the impact of metabolic disorders and oxidant-antioxidant imbalance associated with primary obesity on bone resorption and formation processes. Anthropometric parameters, metabolic variables, oxidative stress indicators (malondialdehyde, vitamins A and E, uric acid, superoxide dismutase, catalase, glutathione peroxidase, type 1 paraoxonase, iron-reducing plasma antioxidant power) and markers of bone turnover (type I procollagen N-terminal propeptide and the type I collagen C-terminal cross-linked telopeptide; P1NP and CTX) were assessed in 108 Polish participants. Under the influence of oxidative stress, both enzymatic and non-enzymatic defense mechanisms were stimulated in obese subjects, especially in women, who had increased lipid peroxidation and activity of catalase (particularly in first-degree obesity) and decreased vitamin E concentration. The process of lipid peroxidation, as well as the weakening of the bone formation, was strongly manifested in women at a BMI range of 35.0-39.9 kg/m² but not at BMI > 40.0 kg/m², but it had a comprehensive negative impact on bone turnover in obese men. Obesity and its degree of advancement significantly affected the decrease in the concentration of the marker of bone formation-P1NP-only in the plasma of women. Excessive body weight had no effect on the value of the bone resorption marker in plasma, regardless of gender. Our results confirm the existence of the "obesity paradox" in the aspect of bone tissue metabolism and suggest that a specific body weight threshold changed the molecular response of the tissue.

Associations of Texture Features of Proton Density Fat Fraction Maps between Lumbar Vertebral Bone Marrow and Paraspinal Musculature

Chemical shift encoding-based water−fat MRI (CSE-MRI)-derived proton density fat fraction (PDFF) has been used for non-invasive assessment of regional body fat distributions. More recently, texture analysis (TA) has been proposed to reveal even more detailed information about the vertebral or muscular composition beyond PDFF. The aim of this study was to investigate associations between vertebral bone marrow and paraspinal muscle texture features derived from CSE-MRI-based PDFF maps in a cohort of healthy subjects. In this study, 44 healthy subjects (13 males, 55 ± 30 years; 31 females, 39 ± 17 years) underwent 3T MRI including a six-echo three-dimensional (3D) spoiled gradient echo sequence used for CSE-MRI at the lumbar spine and the paraspinal musculature. The erector spinae muscles (ES), the psoas muscles (PS), and the vertebral bodies L1-4 (LS) were manually segmented. Mean PDFF values and texture features were extracted for each compartment. Features were compared between males and females using logistic regression analysis adjusted for age and body mass index (BMI). All texture features of ES except for Sum Average were significantly (p < 0.05) different between men and women. The three global texture features (Variance, Skewness, Kurtosis) for PS as well as LS showed a significant difference between male and female subjects (p < 0.05). Mean PDFF measured in PS and ES was significantly higher in females, but no difference was found for the vertebral bone marrow’s PDFF. Partial correlation analysis between the texture features of the spine and the paraspinal muscles revealed a highly significant correlation for Variance(global) (r = 0.61 for ES, r = 0.62 for PS; p < 0.001 respectively). Texture analysis using PDFF maps based on CSE-MRI revealed differences between healthy male and female subjects. Global texture features in the lumbar vertebral bone marrow allowed for differentiation between men and women, when the overall PDFF was not significantly different, indicating that PDFF maps may contain detailed and subtle textural information beyond fat fraction. The observed significant correlation of Variance(global) suggests a metabolic interrelationship between vertebral bone marrow and the paraspinal muscles.

Metabolic syndrome and fragility fracture risk

INTRODUCTION

The prevalence of metabolic syndrome has been reported to extremely vary depending on the gender, age, and ethnicity studied. Approximately, 25% of the worldwide adult population is affected by metabolic syndrome, indicating it as a significantly important public health challenge. Likewise, fragility fracture represents an important public health issue too, and the lifetime residual risk of its occurrence has been established in 50% in women and 30% in men over 50 years of age, respectively. Dysmobility syndrome summarizes a cluster of co-existing conditions such as osteoporosis, sarcopenia, obesity. Currently, clinical research focuses essentially on the cardiovascular risks associated with metabolic syndrome. Today, it is conceivable to incorporate all these conditions under a generic "disorder of energy metabolism."

EVIDENCE ACQUISITION

Animal and human studies suggest metabolic and dysmobility syndromes negatively impact on the risk for fragility fracture, contributing to increase the associated mortality rate.

EVIDENCE SYNTHESIS

In recent years, strong correlation between type 2 diabetes, a frequent constitutive part of metabolic syndrome and fragility fracture risk has been reported, but the possible molecular mechanisms by which it can occur are still to be defined.

CONCLUSIONS

Only very few human clinical studies faced these aspects, but they lack adequate endpoints for a good clinical practice in these subjects. Much more still needs to be done before appropriate therapeutic diagnostic pathways will be available for these patients at risk of bone and even generalized fragility. Suggestions for a future overall approach by generating global risk score for these conditions are given.

Sarcopenic obesity and function in women with subacute hip fracture: a short-term prospective study

BACKGROUND

The prognostic role exerted by the concurrent presence of sarcopenia and obesity after hip fracture has not been elucidated.

AIM

To assess the effect of sarcopenic obesity on ability to function in women with subacute hip fracture.

DESIGN

Short-term prospective study.

SETTING

Rehabilitation hospital.

POPULATION

Women with subacute hip fracture.

METHODS

At admission, grip strength, by a Jamar dynamometer, and body composition by dual-energy x-ray absorptiometry were assessed. Sarcopenia was defined according to the criteria released by the European Working Group for Sarcopenia in Older People in 2019, with both grip strength < 16kg and appendicular lean mass (aLM) < 15kg. Alternatively, aLM/(height)2 < 5.5kg/m2 was substituted for aLM < 15kg to confirm sarcopenia in the women with grip strength < 16kg. Obesity was diagnosed with fat mass exceeding 40% of total body mass. Function was assessed by the Barthel index.

RESULTS

We assessed 183 of 200 women. Sarcopenic women had lower Barthel index scores assessed at the end of subacute inpatient rehabilitation (U=300,0; z=-4.3; P<0.001) and lower Batrhel index effectiveness (U=310,0; z=-4.2; P<0.001) than non-sarcopenic women. Conversely, we found no significant differences in function between obese and non-obese women. The concurrent presence of sarcopenia and obesity did not worsen the functional prognosis versus the presence of isolated sarcopenia. After adjustment for Barthel index scores before rehabilitation, age, hip-fracture type and cognitive impairment, sarcopenia was significantly associated with Barthel index scores (P=0.001) and Barthel index effectiveness (P<0.001), whereas obesity was not. The results did not materially change when aLM/(height)2 < 5.5kg/m2 was substituted for aLM <15kg to confirm sarcopenia in the women whose handgrip strength was < 16kg.

CONCLUSIONS

The concurrent presence of obesity did not worsen the negative prognostic role of sarcopenia in the short-term recovery of ability to function after hip fracture in women.

CLINICAL REHABILITATION IMPACT

In women with subacute hip fracture, sarcopenia but not obesity should be assessed to contribute to the prediction of the short-term functional outcome.

Fracture risk assessment in celiac disease: a registry-based cohort study

Celiac disease is associated with an increased fracture risk but is not a direct input to the FRAX® calculation. When celiac disease is considered as a secondary osteoporosis risk factor or BMD is included in the FRAX assessment, FRAX accurately predicts fracture risk.

INTRODUCTION

The fracture risk assessment tool (FRAX®) uses clinical factors and bone mineral density (BMD) measurement to predict 10-year major osteoporotic (MOF) fracture probability. The study aim was to determine whether celiac disease affects MOF risk independent of FRAX score.

METHODS

The Manitoba BMD Registry includes clinical data, BMD measurements, 10-year probability of MOF calculated for each individual using the Canadian FRAX tool and diagnosed celiac disease. Using linkage to population-based healthcare databases, we identified incident MOF diagnoses over the next 10 years for celiac disease and general population cohorts.

RESULTS

Celiac disease (N = 693) was associated with increased fracture risk adjusted for FRAX score computed without secondary osteoporosis or BMD (adjusted hazard ratio [HR] 1.43, 95% confidence interval [CI] 1.11-1.86). Celiac disease was no longer a significant risk factor for fracture when secondary osteoporosis or BMD were included in the FRAX calculation (p > 0.1). In subjects with celiac disease, each SD increase in FRAX score (calculated with and without secondary osteoporosis or BMD) was associated with higher risk of incident MOF (adjusted HR 1.66 to 1.80), similar to the general population (p-interaction > 0.2). Including celiac disease as secondary osteoporosis or including BMD in FRAX 10-year MOF probability calculations (10.1% and 8.6% respectively) approximated the observed cumulative 10-year MOF probability (10.8%, 95% CI 7.8-13.9%).

CONCLUSIONS

Celiac disease is associated with an increased risk of major osteoporotic fractures. When celiac disease is considered as a secondary osteoporosis risk factor or BMD is included in FRAX assessment, FRAX accurately predicts fracture risk.

Age- and BMI-related variations of fat distribution in sacral and lumbar bone marrow and their association with local muscle fat content

This analysis investigated the age- and BMI-related variations of fat distribution in sacral and lumbar bone marrow and their association with local muscle fat content in order to detect fat distribution patterns and variations in healthy adults using proton density fat fraction (PDFF) measurements. A six-echo 3D spoiled gradient-echo sequence was used for chemical shift encoding-based water-fat separation at the sacral and lower lumbar region in 103 healthy volunteers. PDFF values of the sacrum, 5^th lumbar vertebral body, the gluteal and paraspinal muscles were determined. Correlation with age was significant (p < 0.05) for PDFF of the sacrum (men (m): r = 0.58; women (w): r = 0.54), L5 (m: r = 0.58; w: r = 0.54), the gluteal (m: r = 0.51; w: r = 0.44) and paraspinal (m: r = 0.36; w: r = 0.49) muscles in both genders. BMI correlated significantly with the paraspinal musculature in men (r = 0.46) and women (r = 0.33). Correlation testing revealed significant correlations (p < 0.05) between the two osseous (m: r = 0.63, w: r = 0.75) and the muscle compartments (m: r = 0.63, w: r = 0.33) in both genders. Bone marrow and muscle fat infiltration patterns were not significantly associated with each other at the sacral and lower lumbar spine region. The presented data suggest that the two compartments may have distinct pathophysiological fat infiltration patterns. However, further clinical studies are needed to support the results.

Bone Mineral Density, Body Composition, and Mineral Homeostasis Over 24 Months in Urban South African Women With HIV Exposed to Antiretroviral Therapy

Human immunodeficiency virus- (HIV-) infection and antiretroviral therapy (ART) exposure are associated with bone loss. African data are limited despite the region's HIV burden. Of 247 ART-naïve, premenopausal, urban, black African women aged 33.9 ± 6.6 years from Soweto, South Africa, measured at baseline, 110 underwent anthropometry, DXA, and blood and urine collections at 12 and 24 months; 39 were HIV-negative (Nref), 28 were people with HIV (PWH) not ART-exposed for the duration of the study (ART-N), and 43 were PWH who were ART-exposed within the first 12 months (ART-Y). At baseline, the ART-Y group had lower BMI and fat mass than the Nref group. Within 12 months of ART initiation, areal bone mineral density (aBMD) had decreased at the lumbar spine and at the whole body less head, despite increased weight, and hip aBMD had not increased in line with the Nref group. There was no evidence of further bone changes between 12 and 24 months. By 24 months, the ART-Y women had gained weight and fat mass, but remained lighter with less fat than the Nref women. ART initiation normalized the low serum albumin of the ART-Y group at baseline, but was associated with elevated bone turnover markers at 12 and 24 months. Vitamin D status and renal phosphate handling were normal. ART-N had similar aBMD and other characteristics to the Nref group throughout, except unlike the Nref group, weight and fat mass did not increase and serum albumin decreased. This study in African women of childbearing age demonstrated that the bone loss that had occurred in these PWH after ART initiation did not continue after 12 months and that bone loss did not occur in ART-unexposed PWH over 2 years. At 24 months, despite gains in weight and fat mass, ART-exposed women remained lighter, with lower aBMD, fat mass, and higher bone turnover than women without HIV. More studies are required to establish if the bone loss and fat gain reverse, stabilize, or continue with further ART exposure, particularly during and after menopause. © 2020 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Energy partitioning between fat and bone mass is controlled via a hypothalamic leptin/NPY relay

BACKGROUND/OBJECTIVES

Maintaining energy balance is important to ensure a healthy organism. However, energy partitioning, coordinating the distribution of sufficient energy to different organs and tissues is equally important, but the control of this process is largely unknown. In obesity, an increase in fat mass necessitates the production of additional bone mass to cope with the increase in bodyweight and processes need to be in place to communicate this new weight bearing demand. Here, we investigate the interaction between leptin and NPY, two factors critically involved in the regulation of both energy metabolism and bone mass, in this process.

METHODS

We assessed the co-localization of leptin receptors on NPY neurons using RNAScope followed by a systematic examination of body composition and energy metabolism profiling in male and female mice lacking leptin receptors specifically in NPY neurons (Lepr^lox/lox;NPY^Cre/+). The effect of short-term switching between chow and high-fat diet was also examined in these mice.

RESULTS

We uncovered that leptin receptor expression is greater on a subpopulation of NPY neurons in the arcuate that do not express AgRP. We further show that Lepr^lox/lox;NPY^Cre/+ mice exhibit significantly increased adiposity while bone mass is diminished. These body composition changes occur in the absence of alterations in food intake or energy expenditure, demonstrating a prominent role for leptin signaling in NPY neurons in the control of energy partitioning. Importantly however, when fed a high-fat diet, these mice display a switch in energy partitioning whereby they exhibit a significantly enhanced ability to increase their bone mass to match the increased bodyweight caused by higher caloric intake concurrent with attenuated adiposity.

CONCLUSIONS

Taken together, these results demonstrate that leptin signaling in NPY neurons is critical for coordinating energy partitioning between fat and bone mass especially during situations of changes in energy balance.

Pathophysiology and Management of Type 2 Diabetes Mellitus Bone Fragility

Individuals with type 2 diabetes mellitus (T2DM) have an increased risk of bone fragility fractures compared to nondiabetic subjects. This increased fracture risk may occur despite normal or even increased values of bone mineral density (BMD), and poor bone quality is suggested to contribute to skeletal fragility in this population. These concepts explain why the only evaluation of BMD could not be considered an adequate tool for evaluating the risk of fracture in the individual T2DM patient. Unfortunately, nowadays, the bone quality could not be reliably evaluated in the routine clinical practice. On the other hand, getting further insight on the pathogenesis of T2DM-related bone fragility could consent to ameliorate both the detection of the patients at risk for fracture and their appropriate treatment. The pathophysiological mechanisms underlying the increased risk of fragility fractures in a T2DM population are complex. Indeed, in T2DM, bone health is negatively affected by several factors, such as inflammatory cytokines, muscle-derived hormones, incretins, hydrogen sulfide (H2S) production and cortisol secretion, peripheral activation, and sensitivity. All these factors may alter bone formation and resorption, collagen formation, and bone marrow adiposity, ultimately leading to reduced bone strength. Additional factors such as hypoglycemia and the consequent increased propensity for falls and the direct effects on bone and mineral metabolism of certain antidiabetic medications may contribute to the increased fracture risk in this population. The purpose of this review is to summarize the literature evidence that faces the pathophysiological mechanisms underlying bone fragility in T2DM patients.

Interleukin-6 Knockout Inhibits Senescence of Bone Mesenchymal Stem Cells in High-Fat Diet-Induced Bone Loss

Obesity, a chronic low-grade inflammatory state, not only promotes bone loss, but also accelerates cell senescence. However, little is known about the mechanisms that link obesity, bone loss, and cell senescence. Interleukin-6 (IL-6), a pivotal inflammatory mediator increased during obesity, is a candidate for promoting cell senescence and an important part of senescence-associated secretory phenotype (SASP). Here, wild type (WT) and (IL-6 KO) mice were fed with high-fat diet (HFD) for 12 weeks. The results showed IL-6 KO mice gain less weight on HFD than WT mice. HFD induced trabecular bone loss, enhanced expansion of bone marrow adipose tissue (BMAT), increased adipogenesis in bone marrow (BM), and reduced the bone formation in WT mice, but it failed to do so in IL-6 KO mice. Furthermore, IL-6 KO inhibited HFD-induced clone formation of bone marrow cells (BMCs), and expression of senescence markers (p53 and p21). IL-6 antibody inhibited the activation of STAT3 and the senescence of bone mesenchymal stem cells (BMSCs) from WT mice in vitro, while rescued IL-6 induced senescence of BMSCs from IL-6 KO mice through the STAT3/p53/p21 pathway. In summary, our data demonstrated that IL-6 KO may maintain the balance between osteogenesis and adipogenesis in BM, and restrain senescence of BMSCs in HFD-induced bone loss.

Association of Osteoporosis with Anthropometric Measures in a Representative Sample of Iranian Adults: The Iranian Multicenter Osteoporosis Study

BACKGROUND

Osteoporosis and obesity are two major public health problems worldwide. Considering the conflicting results about the association between anthropometric measurement and bone mineral density (BMD) and also differences between various races, this study was designed to examine the relationship between anthropometric measurements and BMD in a sample of Iranian adults.

METHODS

This cross-sectional population-based study was conducted on 2625 Iranian adults aged 18 and above who were selected using multistage, cluster sampling method from Sanandaj and Arak (two cities of Iran). The evaluated variables included age, sex, height, weight, body mass index (BMI), BMD, and waist and hip circumferences. The correlations between anthropometric measures and BMD in three bone areas (total hip, femoral neck, and spine) were observed in four sex/age groups (men <50 years, men ≥50 years, and pre- and postmenopausal women).

RESULTS

Of all the 2625 participants in the Iranian Multicenter Osteoporosis Study, 2022 (1303 women and 719 men) entered into our survey and were stratified into four sex/age groups. According to the results, increasing BMI was directly associated with BMD increase, while an inverse association was observed between waist-to-hip ratio (WHR) and total hip BMD. In a similar analysis on the femoral neck and WHR, the correlation coefficients in premenopausal women and men ≥50 years were reported as being the highest and the lowest, respectively, among the four groups.

CONCLUSIONS

Our results showed that high BMI is a protective factor (positive correlation), and high WHR is a risk factor for osteoporosis, although it should be reminded that we could not specifically define which factors including lean tissue mass, fat mass, and total weight are really affecting BMD increase in the overweight/obese participants.

Influence of body mass index on health-related quality of life after surgical treatment of intra-articular distal radius fractures. A retrospective 7-year follow-up study

Morbid obesity is associated with reduced health-related quality of life (HRQOL), increased morbidity and mortality. Little is known about the correlation between obesity and complex distal radius fractures (DRF). The purpose of this study was to examine the effect of being overweight on postoperative HRQOL after surgically treated intra-articular DRF. Fifty-three patients were included in this retrospective study with 7 years' mean follow-up (mean 7.2±0.4, range 6.4-7.9 years) after volar plating of an intra-articular DRF (AO-type C). All patients were categorized by their body mass index (BMI) into two study groups: group 1 (normal weight) with a BMI<25 (n=24); group 2 (obese) with a BMI≥25 (n=29). HRQOL and functional outcomes were assessed through range of motion (ROM) and four different scores - the 36-item short form health survey (SF-36), the disability of arm and shoulder score (DASH), the Gartland and Werley score and the Castaing score - along with X-rays to measure volar tilt, radial inclination, radial length and articular congruity. All HRQOL assessments and clinical outcomes were correlated to BMI by comparing group 1 versus group 2. There was no difference in terms of postoperative ROM. The group of normal weight patients achieved slightly better but non-significant results for the Gartland and Werley score. No differences were seen in the DASH score or SF-36. There were also no differences regarding the Castaing score. Overall, normal and obese patients had no significant differences their HRQOL and functionality after volar plating of DRF.

The relationship between obesity and fractures

There has been very limited analysis of the relationship between obesity and fractures in the orthopaedic literature. It has been established for some years that underweight individuals are at greater risk of proximal femoral fractures but recently there has been interest in the susceptibility of obese post-menopausal females to fracture. We have undertaken an analysis of 4886 adult patients who presented with a fracture and had their BMI assessed. Analysis has confirmed the relationship between underweight individuals and proximal femoral fractures but there is also a negative association between obesity and clavicle fractures in males and females and with calcaneal fractures in females. There is a positive relationship between obesity and proximal humeral, finger phalangeal and ankle fractures in males and with humeral diaphyseal, carpal and ankle fractures in females. There was no relationship found between open or multiple fractures and obesity.

Erythropoietin modulates bone marrow stromal cell differentiation

Erythropoietin is essential for bone marrow erythropoiesis and erythropoietin receptor on non-erythroid cells including bone marrow stromal cells suggests systemic effects of erythropoietin. Tg6 mice with chronic erythropoietin overexpression have a high hematocrit, reduced trabecular and cortical bone and bone marrow adipocytes, and decreased bone morphogenic protein 2 driven ectopic bone and adipocyte formation. Erythropoietin treatment (1 200 IU·kg^–1) for 10 days similarly exhibit increased hematocrit, reduced bone and bone marrow adipocytes without increased osteoclasts, and reduced bone morphogenic protein signaling in the bone marrow. Interestingly, endogenous erythropoietin is required for normal differentiation of bone marrow stromal cells to osteoblasts and bone marrow adipocytes. ΔEpoR_E mice with erythroid restricted erythropoietin receptor exhibit reduced trabecular bone, increased bone marrow adipocytes, and decreased bone morphogenic protein 2 ectopic bone formation. Erythropoietin treated ΔEpoR_E mice achieved hematocrit similar to wild-type mice without reduced bone, suggesting that bone reduction with erythropoietin treatment is associated with non-erythropoietic erythropoietin response. Bone marrow stromal cells from wild-type, Tg6, and ΔEpoR_E-mice were transplanted into immunodeficient mice to assess development into a bone/marrow organ. Like endogenous bone formation, Tg6 bone marrow cells exhibited reduced differentiation to bone and adipocytes indicating that high erythropoietin inhibits osteogenesis and adipogenesis, while ΔEpoR_E bone marrow cells formed ectopic bones with reduced trabecular regions and increased adipocytes, indicating that loss of erythropoietin signaling favors adipogenesis at the expense of osteogenesis. In summary, endogenous erythropoietin signaling regulates bone marrow stromal cell fate and aberrant erythropoietin levels result in their impaired differentiation.

DIAGNOSIS OF ENDOCRINE DISEASE: Evaluation of bone fragility in endocrine disorders

An underlying disease affecting bone health is present in up to 40% and 60% of osteoporotic post-menopausal women and men respectively. Among the disorders leading to a secondary form of osteoporosis, the endocrine diseases are highly represented. A frequent finding in patients affected with an endocrine-related forms of bone disease is that the skeletal fragility is partially independent of the bone density, since the fracture risk in these patients is related more to a reduction of bone quality than to a decrease of bone mass. As a consequence, bone mineral density evaluation by dual-X-ray Absorptiometry may be inadequate for establishing the risk of fracture in the setting of the endocrine-related forms of osteoporosis. In the recent years several attempts to non-invasively estimating bone quality have been done. Nowadys, some new tools are available in the clinical practice for optimizing the fracture risk estimation in patients with endocrine disorders. The aim of this review is to summarise the evidences regarding the role of the different imaging tools for evaluating bone density and bone quality in the most frequent forms of endocrine-related osteoporosis, such as obesity, diabetes, acromegaly, thyrotoxicosis, primary hyperparathyroidism, hypercortisolism and hypogonadism. For each of these disorders, data regarding both the current available tools and the future possible new techniques for assessing bone fragility in patients with endocrine diseases are reported.

The Impact of Obesity on Orthopedic Upper Extremity Surgery

Obese patients have increased rates of upper extremity injury, carpal tunnel syndrome, and upper extremity osteoarthritis. Preoperative considerations include cardiovascular disease, pulmonary disease, and diabetes mellitus. Intraoperative and anesthetic considerations include specialized equipment, patient positioning, and the physiology of obese patients. Postoperative considerations should include increased risk of cardiovascular complications as well as surgical site infections and malunion. Surgery of the hand and upper extremity may be less prone to the postoperative complications seen in other regions of the body. There are currently no direct contraindications for obese patients to undergo orthopedic procedures if the appropriate considerations have been made.

Complex interplay among adiposity, insulin resistance and bone health

Obesity and osteoporosis are common public health problems. Paradoxically, while obesity is associated with higher bone density, type 2 diabetic obese individuals have an increased fracture risk. Although obesity and insulin resistance co-exist, some obese individuals remain insulin-sensitive. We suggest that the apparent paradox relating obesity, bone density and fracture risk in type 2 diabetes may be at least partly influenced by differences in bone strength and quality between insulin-resistant and insulin-sensitive obese individuals. In this review, we focus on the complex interplay between, adiposity, insulin resistance and osteoporotic fracture risk and suggest that this is an important area of study that has implications for individually tailored and targeted treatment to prevent osteoporotic fracture in obese type 2 diabetic individuals.

The Role of BMI in Hip Fracture Surgery

Introduction:

Obesity is an oft-cited cause of surgical morbidity and many institutions require extensive supplementary screening for obese patients prior to surgical intervention. However, in the elderly patients, obesity has been described as a protective factor. This article set out to examine the effect of body mass index (BMI) on outcomes and morbidity after hip fracture surgery.

Methods:

The National Surgical Quality Improvement Program database was queried for all patients undergoing 1 of 4 surgical procedures to manage hip fracture between 2008 and 2012. Patient demographics, BMI, and known factors that lead to poor surgical outcomes were included as putative predictors for complications that included infectious, cardiac, pulmonary, renal, and neurovascular events. Using χ² tests, 30-day postoperative complication rates were compared between 4 patient groups stratified by BMI as low weight (BMI < 20), normal (BMI = 20-30), obese (BMI = 30-40), and morbidly obese (BMI > 40).

Results:

A total of 15 108 patients underwent surgery for hip fracture over the examined 5-year period. Of these, 18% were low weight (BMI < 20), 67% were normal weight (BMI = 20-30), 13% were obese (BMI = 30-40), and 2% were morbidly obese (BMI > 40). The low-weight and morbidly obese patients had both the highest mortality rates and the lowest superficial infection rates. There was a significant increase in blood transfusion rates that decreased linearly with increasing BMI. Deep surgical site infection and renal failure increased linearly with increasing BMI, however, these outcomes were confounded by comorbidities.

Conclusion:

This study demonstrates that patients at either extreme of the BMI spectrum, rather than solely the obese, are at greatest risk of major adverse events following hip fracture surgery. This runs contrary to the notion that obese hip fracture patients automatically require additional preoperative screening and perioperative services, as currently implemented in many institutions.

Associations Between Lumbar Vertebral Bone Marrow and Paraspinal Muscle Fat Compositions-An Investigation by Chemical Shift Encoding-Based Water-Fat MRI

Purpose: Advanced magnetic resonance imaging (MRI) methods enable non-invasive quantification of body fat situated in different compartments. At the level of the lumbar spine, the paraspinal musculature is the compartment spatially and functionally closely related to the vertebral column, and both vertebral bone marrow fat (BMF) and paraspinal musculature fat contents have independently shown to be altered in various metabolic and degenerative diseases. However, despite their close relationships, potential correlations between fat compositions of these compartments remain largely unclear. Materials and Methods: Thirty-nine female subjects (38.5% premenopausal women, 29.9 ± 7.1 years; 61.5% postmenopausal women, 63.2 ± 6.3 years) underwent MRI at 3T of the lumbar spine using axially- and sagittally-prescribed gradient echo sequences for chemical shift encoding-based water-fat separation. The erector spinae muscles and vertebral bodies of L1-L5 were segmented to determine the proton density fat fraction (PDFF) of the paraspinal and vertebral bone marrow compartments. Correlations were calculated between the PDFF of the paraspinal muscle and bone marrow compartments. Results: The average PDFF of the paraspinal muscle and bone marrow compartments were significantly lower in premenopausal women when compared to postmenopausal women (11.6 ± 2.9% vs. 24.6 ± 7.1% & 28.8 ± 8.3% vs. 47.2 ± 8.5%; p < 0.001 for both comparisons). In premenopausal women, no significant correlation was found between the PDFF of the erector spinae muscles and the PDFF of the bone marrow of lumbar vertebral bodies (p = 0.907). In contrast, a significant correlation was shown in postmenopausal women (r = 0.457, p = 0.025). Significance was preserved after inclusion of age and body mass index (BMI) as control variables (r = 0.472, p = 0.027). Conclusion: This study revealed significant correlations between the PDFF of paraspinal and vertebral bone marrow compartments in postmenopausal women. The PDFF of the paraspinal and vertebral bone marrow compartments and their correlations might potentially serve as biomarkers; however, future studies including more subjects are required to evaluate distinct clinical value and reliability. Future studies should also follow up our findings in patients suffering from metabolic and degenerative diseases to clarify how these correlations change in the course of such diseases.

Mechanical signals protect stem cell lineage selection, preserving the bone and muscle phenotypes in obesity

The incidence of obesity is rapidly rising, increasing morbidity and mortality rates worldwide. Associated comorbidities include type 2 diabetes, heart disease, fatty liver disease, and cancer. The impact of excess fat on musculoskeletal health is still unclear, although it is associated with increased fracture risk and a decline in muscular function. The complexity of obesity makes understanding the etiology of bone and muscle abnormalities difficult. Exercise is an effective and commonly prescribed nonpharmacological treatment option, but it can be difficult or unsafe for the frail, elderly, and morbidly obese. Exercise alternatives, such as low-intensity vibration (LIV), have potential for improving musculoskeletal health, particularly in conditions with excess fat. LIV has been shown to influence bone marrow mesenchymal stem cell differentiation toward higher-order tissues (i.e., bone) and away from fat. While the exact mechanisms are not fully understood, recent studies utilizing LIV both at the bench and in the clinic have demonstrated some efficacy. Here, we discuss the current literature investigating the effects of obesity on bone, muscle, and bone marrow and how exercise and LIV can be used as effective treatments for combating the negative effects in the presence of excess fat.

Low health related quality of life associated with fractures in obese postmenopausal women in Santa Maria, Brazil

Although health-related quality of life is well studied in subjects with obesity or fractures, there are few studies approaching both diseases together. The aim of this study was to evaluate the health-related quality of life (HRQL) in obese postmenopausal women with fractures. A cross-sectional study was carried out at Santa Maria, Brazil. Postmenopausal women aged 55 years or older were recruited from March 1st to August 31st, 2013. Women with cognitive impairment were excluded. The Short-Form Health Survey (SF-36) were applied (QM0 16,471). Height and weight were measured according to the World Health Organization protocol. Bone fractures (excluding hand, feet, and head) that occur after age 45 years were considered as the outcome.

Of the 1057 women allocated to study, 975 had their weight and height measured. Obese women with fractures had significantly lower SF-36 physical component scores when compared with non-obese subjects with fracture, obese subjects without fractures, and non-obese non-fracture subjects. Both obesity and fractures were independently associated with a lower SF-36 physical component score in the regression model. In conclusion, fractures appear to have an adverse effect on quality of life which is more pronounced in obese postmenopausal women.

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Although health-related quality of life is well studied in subjects with obesity or fractures, there are few studies approaching both afflictions together.

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Obese subjects with fractures have the lowest quality of life when compared with non-obese subjects with fracture, obese subjects without fractures, and non-obese non-fracture subjects.

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Obesity and fractures are independently associated with health-related quality of life at the regression analysis.

Effects of obesity treatments on bone mineral density, bone turnover and fracture risk in adults with overweight or obesity

BACKGROUND

New evidence suggests that obesity is deleterious for bone health, and obesity treatments could potentially exacerbate this.

MATERIALS AND METHODS

This narrative review, largely based on recent systematic reviews and meta-analyses, synthesizes the effects on bone of bariatric surgery, weight loss pharmaceuticals and dietary restriction.

RESULTS AND CONCLUSIONS

All three obesity treatments result in statistically significant reductions in hip bone mineral density (BMD) and increases in bone turnover relative to pre-treatment values, with the reductions in hip BMD being strongest for bariatric surgery, notably Roux-en Y gastric bypass (RYGB, 8%-11% of pre-surgical values) and weakest for dietary restriction (1%-1.5% of pre-treatment values). Weight loss pharmaceuticals (orlistat or the glucagon-like peptide-1 receptor agonist, liraglutide) induced no greater changes from pre-treatment values than control, despite greater weight loss. There is suggestive evidence that liraglutide may increase bone mineral content (BMC) - but not BMD - and reduce fracture risk, but more research is required to clarify this. All three obesity treatments have variable effects on spine BMD, probably due to greater measurement error at this site in obesity, suggesting that future research in this field could focus on hip rather than spine BMD. Various mechanisms have been proposed for BMD loss with obesity treatments, notably reduced nutritional intake/absorption and insufficient exercise, and these are potential avenues for protection against bone loss. However, a pressing outstanding question is whether this BMD reduction contributes to increased fracture risk, as has been observed after RYGB, and whether any such increase in fracture risk outweighs the risks of staying obese (unlikely).

Obesity in Older Adults

The percentage of older obese adults is on the rise. Many clinicians underestimate the health consequences of obesity in the elderly, citing scarce evidence and concerns that weight loss might be detrimental to the health of older adults. Although overweight and obese elders are not at the same risk for morbidity and mortality as younger individuals, quality of life and function are adversely impacted. Weight loss plans in the elderly should include aerobic activities as well as balance and resistance activities to maintain optimal physical function.

Involvement of skeletal renin-angiotensin system and kallikrein-kinin system in bone deteriorations of type 1 diabetic mice with estrogen deficiency

AIMS

This study was aimed to investigate the involvement of skeletal renin-angiotensin system (RAS) and kallikrein-kinin system (KKS) in bone deteriorations of mice in response to the combination treatment of estrogen deficiency and hyperglycemia.

METHODS

The female C57BL/6J mice were sham-operated or ovariectomized with vehicle or streptozotocin (STZ) treatment. Two weeks later, the biochemistries in serum and urine were determined by standard colorimetric methods or ELISA. The H&E and TRAP staining were performed at the tibial proximal metaphysis. The polymerase chain reaction and immunoblotting were applied for molecular analysis on mRNA and protein expression.

RESULTS

The mice after treating with ovariectomy and STZ showed the decreased level of serum Ca and the increased level of serum PTH and urine Ca. The H&E staining showed trabecular bone abnormalities as demonstrated by the loss, disconnection and separation of trabecular bone network as well as the loss of chondrocytes and appearance of chondrocyte cluster at growth plate of tibia. The significant increase of matured osteoclast number was shown in group with double treatments. The combination treatment significantly up-regulated mRNA expression of AGT, ACE, renin receptor, MMP-9 and CAII, and protein expression of renin, and decreased the ratio of OPG/RANKL and the expression of bradykinin receptors in bone tissue.

CONCLUSION

Ovariectomy combined with STZ induction produced more detrimental actions on bone through the activation of local bone RAS and the down-regulation of bradykinin receptors, as compared to the respective single treatment.

MR-Based Assessment of Bone Marrow Fat in Osteoporosis, Diabetes, and Obesity

Bone consists of the mineralized component (i.e., cortex and trabeculae) and the non-mineralized component (i.e., bone marrow). Most of the routine clinical bone imaging uses X-ray-based techniques and focuses on the mineralized component. However, bone marrow adiposity has been also shown to have a strong linkage with bone health. Specifically, multiple previous studies have demonstrated a negative association between bone marrow fat fraction (BMFF) and bone mineral density. Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) are ideal imaging techniques for non-invasively investigating the properties of bone marrow fat. In the present work, we first review the most important MRI and MRS methods for assessing properties of bone marrow fat, including methodologies for measuring BMFF and bone marrow fatty acid composition parameters. Previous MRI and MRS studies measuring BMFF and fat unsaturation in the context of osteoporosis are then reviewed. Finally, previous studies investigating the relationship between bone marrow fat, other fat depots, and bone health in patients with obesity and type 2 diabetes are presented. In summary, MRI and MRS are powerful non-invasive techniques for measuring properties of bone marrow fat in osteoporosis, obesity, and type 2 diabetes and can assist in future studies investigating the pathophysiology of bone changes in the above clinical scenarios.

The Trochanteric Localization is a Mediator of Slower Short-Term Functional Recovery in Overweight and Obese Elderly Women with Recent Hip Fracture: The BREAK Study

The hypothesis tested in this study, carried out on elderly Italian women with recent hip fracture, was to assess the extent to which the effect of a condition of being overweight/obese on short-term functional recovery as evaluated by the "time to permitted load" could be explained by a mediator variable (type of hip fracture). We studied 727 women aged 60 years or over with a recent low trauma surgically treated hip fracture and for whom an information on post-surgery complications and on the time to permitted load was available. To assess for mediation, the statistical analyses were carried out following the procedure described by Baron and Kenny. In this study, 46 % of women with hip fracture presented a time to permitted load of ≥ 10 days. The women with a post-surgery time to permitted load of ≥ 10 days showed a significantly higher proportion of trochanteric fracture localization (72.1 vs 42 %), of total overweight/obesity (46.5 vs 36.8 %) and of post-surgery complications (38.8 vs 18.8 %). The mediating effect of hip fracture localization on the association between overweight/obesity and the time of permitted load was demonstrated and confirmed in a multivariate logistic regression model. This study, carried out using a "mediator" statistical analysis, suggests that in elderly women with hip fracture being overweight/obese is associated with a slower short-term functional recovery as evaluated by the time to permitted load and that this association is mediated by the trochanteric localization of hip fracture.

Osteoporosis epidemiology 2013: implications for diagnosis, risk assessment, and treatment

PURPOSE OF REVIEW

To summarize the recently published studies that provide insights into the changing epidemiology of osteoporosis and fractures.

RECENT FINDINGS

The main themes reviewed are fracture outcomes; trends in fractures rates; fracture risk assessment and monitoring; atypical femoral fractures; male osteoporosis; falls and physical activity; and sarcopenia, obesity, and metabolic syndrome.

SUMMARY

Osteoporotic fractures were found to have long-term consequences on excess mortality (10 years) and economic costs (5 years). The large burden of nonhip nonvertebral fractures has been underestimated. Divergent (but mostly declining) trends in fracture rates were confirmed in several cohorts from around the world. This has significant implications for healthcare planners and clinicians responsible for the care of individuals with osteoporosis, and also impacts on the calibration of fracture prediction tools. Although fracture prediction tools differ in their complexity, performance characteristics are similar when applied to the general population. Large, high-quality comparative studies with different case mixes are needed. Fracture probability does not appear to be responsive enough to support goal-directed treatment at this time. A consensus on the diagnosis of osteoporosis in men has emerged, based upon the same absolute bone density cutoff for both men and women. Finally, a plethora of new data highlight the importance of falls, physical activity, and body composition as contributors to skeletal health.

Gold nanoparticles promote osteogenic differentiation in human adipose-derived mesenchymal stem cells through the Wnt/β-catenin signaling pathway

Gold nanoparticles (AuNPs) are attractive materials for use in biomedicine due to their physical properties. Increasing evidence suggests that several nanoparticles induce the differentiation of human mesenchymal stem cells into osteoblasts and adipocytes. In this study, we hypothesized that chitosan-conjugated AuNPs promote the osteogenic differentiation of human adipose-derived mesenchymal stem cells. For the evaluation of osteogenic differentiation, alizarin red staining, an alamarBlue(®) assay, and a quantitative real-time polymerase chain reaction analysis were performed. In order to examine specific signaling pathways, immunofluorescence and a western blotting assay were performed. Our results demonstrate that chitosan-conjugated AuNPs increase the deposition of calcium content and the expression of marker genes related to osteogenic differentiation in human adipose-derived mesenchymal stem cells at nontoxic concentrations. These results indicate that chitosan-conjugated AuNPs promote osteogenesis through the Wnt/β-catenin signaling pathway. Therefore, chitosan-conjugated AuNPs can be used as a reagent for promoting bone formation.

The neuropeptide Y-ergic system: potential therapeutic target against bone loss with obesity treatments

Obesity is no longer considered to provide protection against osteoporosis. Moreover, treatments for obesity are now suspected of reducing bone mass. With the escalating incidence of obesity, combined with increases in the frequency, duration and intensity of interventions used to combat it, we face a potential increase in health burden due to osteoporotic fractures. The neuropeptide Y-ergic system offers a potential target for the prevention and anabolic treatment of bone loss in obesity, due to its dual role in the regulation of energy homeostasis and bone mass. Although the strongest stimulation of bone mass by this system appears to occur via indirect hypothalamic pathways involving Y2 receptors (one of the five types of receptors for neuropeptide Y), Y1 receptors on osteoblasts (bone-forming cells) induce direct effects to enhance bone mass. This latter pathway may offer a suitable target for anti-osteoporotic treatment while also minimizing the risk of adverse side effects.

Divergent effects of obesity on fragility fractures

Obesity was commonly thought to be advantageous for maintaining healthy bones due to the higher bone mineral density observed in overweight individuals. However, several recent studies have challenged the widespread belief that obesity is protective against fracture and have suggested that obesity is a risk factor for certain fractures. The effect of obesity on fracture risk is site-dependent, the risk being increased for some fractures (humerus, ankle, upper arm) and decreased for others (hip, pelvis, wrist). Moreover, the relationship between obesity and fracture may also vary by sex, age, and ethnicity. Risk factors for fracture in obese individuals appear to be similar to those in nonobese populations, although patterns of falling are particularly important in the obese. Research is needed to determine if and how visceral fat and metabolic complications of obesity (type 2 diabetes mellitus, insulin resistance, chronic inflammation, etc) are causally associated with bone status and fragility fracture risk. Vitamin D deficiency and hypogonadism may also influence fracture risk in obese individuals. Fracture algorithms such as FRAX^® might be expected to underestimate fracture probability. Studies specifically designed to evaluate the antifracture efficacy of different drugs in obese patients are not available; however, literature data may suggest that in obese patients higher doses of the bisphosphonates might be required in order to maintain efficacy against nonvertebral fractures. Therefore, the search for better methods for the identification of fragility fracture risk in the growing population of adult and elderly subjects with obesity might be considered a clinical priority which could improve the prevention of fracture in obese individuals.

Obesity as a Factor Contributing to Falls by Older Adults

The growth of the worldwide population of older adults presents significant challenges, many inter-related, that range from the health of individuals to the health of national economies. In the US, more than one-third of older adults may be obese, a condition that may independently increase the risk for mobility impairment, fall-related injury and, possibly, costs of post-injury treatment and care. The effectiveness of conventional exercise-based fall prevention programs is significant but smaller than both the annual rate of falling of older adults and rate of growth of this population, who are at greatest risk for injurious falls. The anthropometric and functional consequences of obesity may impose limitations on the ability to perform compensatory stepping responses following large postural disturbances. The focus of this paper is the potential of task-specific training to improve compensatory stepping responses and reduce falls by obese people given the individual-specific anthropometric and functional consequences of obesity.

Obesity and fractures

Until recently obesity was believed to be protective against fractures. However, a report from a Fracture Liaison Clinic in the UK (2010) reported a surprisingly high proportion of obese postmenopausal women attending the clinic with fractures, and in the GLOW study (2011), a similar prevalence and incidence of fractures in obese and non-obese postmenopausal women was observed. Subsequently, other studies have demonstrated the importance of obesity in the epidemiology of fractures. Obese women are at increased risk of fracture in ankle, leg, humerus, and vertebral column and at lower risk of wrist, hip and pelvis fracture when compared to non-obese women. In men, it has been reported that multiple rib fractures are associated with obesity. Furthermore, falls appear to play an important role in the pathogenesis of fractures in obese subjects. Regarding hip fracture and major fractures, the FRAX algorithm has proven to be a useful predictor in obese individuals. Obese people are less likely to receive bone protective treatment; they have a longer hospital stay and a lower quality of life both before and after fracture. Moreover, the efficacy of antiresorptive therapies is not well established in obese people. The latter is a field for future research.

Insights from the Global Longitudinal Study of Osteoporosis in Women (GLOW)

GLOW is an observational, longitudinal, practice-based cohort study of osteoporosis in 60,393 women aged ≥55 years in 10 countries on three continents. In this Review, we present insights from the first 3 years of the study. Despite cost analyses being frequently based on spine and hip fractures, we found that nonvertebral, nonhip fractures were around five times more common and doubled the use of health-care resources compared with hip and spine fractures combined. Fractures not at the four so-called major sites in FRAX(®) (upper arm, forearm, hip and clinical vertebral fractures) account for >40% of all fractures. The risk of fracture is increased by various comorbidities, such as Parkinson disease, multiple sclerosis and lung and heart disease. Obesity, although thought to be protective against all fractures, substantially increased the risk of fractures in the ankle or lower leg. Simple assessment by age plus fracture history has good predictive value for all fractures, but risk profiles differ for first and subsequent fractures. Fractures diminish quality of life as much or more than diabetes mellitus, arthritis and lung disease, yet women substantially underestimate their own fracture risk. Treatment rates in patients at high risk of fracture are below those recommended but might be too frequent in women at low risk. Comorbidities and the limits of current therapeutic regimens jeopardize the efficacy of drugs; new regimens should be explored for severe cases.