Relationship of adiposity to bone volumetric density and microstructure in men and women across the adult lifespan

[Epidemiological survey of osteoporosis in Beijing over the past decade: a single-center analysis of dual-energy X-ray absorptiometry scans from 30 599 individuals]

OBJECTIVES

To analyze bone mass distribution and the factors affecting bone mass in a general Chinese Han cohort undergoing physical examinations at our center.

METHODS

We retrospectively collected the data of bone mineral density (BMD) measurements from 30 599 healthy Han Chinese adults (age≥20 years) who underwent dual-energy X-ray absorptiometry scans at our hospital from July, 2013 to July, 2023. Basic parameters including height, body weight, and gender were recorded, and descriptive statistics and correlation analyses were performed using R software.

RESULTS

In this cohort, the male individuals had a mean peak BMD of 1.00±0.12 g/cm2 in the lumbar vertebrae, 0.94±0.14 g/cm2 in the femoral neck, and 0.99±0.13 g/cm2 in the total hip, significantly higher than the values in the female individuals [0.99±0.12 g/cm2 in the lumbar vertebrae (P=0.022), 0.79±0.11 g/cm2 in the femoral neck (P<0.001), and 0.88±0.11 g/cm2 in the total hip (P<0.001)]. In the overall cohort, the BMD values of the lumbar spine and femur decreased with age after reaching their peak levels. There was a positive correlation between BMD value and body mass index (BMI) in both male and female individuals. The 2013-2014 period recorded the lowest BMD values in the lumbar, hip, and femoral neck, which tended to increase steadily in the following years (2015-2023).

CONCLUSIONS

Our data suggest that the BMD values vary among different populations, and future multi-center studies using more accurate BMD detection technology are warranted to capture the variation patterns of BMD with demographic characteristics of specific populations.

Association between systemic immune-inflammation index and trimethylamine N-oxide levels in peripheral blood and osteoporosis in overweight and obese patients

Background

The intricate relationship between systemic immune-inflammation index (SII) and trimethylamine N-oxide (TMAO) in the peripheral blood and osteoporosis (OP) remains unclear. This study aims to investigate variations in the levels of SII and TMAO in the peripheral blood of overweight and obese patients, and examine the associations between these markers, bone mineral density (BMD), and the occurrence of osteoporotic fractures.

Methods

The study enrolled 765 patients aged ≥ 50 years with BMI ≥ 24 kg/m², dividing them into two groups based on visceral fat area (VFA): <100 cm² and ≥100 cm². A corrected regression model analyzed the association of SII, TMAO, BMD, and osteoporotic fractures incidence in patients with central obesity. Receiver operator characteristic (ROC) curves assessed the predictive ability of SII and TMAO for OP screening.

Results

Baseline data showed that patients with VFA ≥ 100 cm² had lower whole body (WB) and lumbar spine (LS) BMD, but higher SII and TMAO levels compared to those with VFA < 100 cm² (p < 0.05). Particularly in the group with VFA ≥ 100 cm2, there was an upward trend in SII and TMAO as bone mass decreased. Regression analysis found SII and TMAO negatively correlated with WB, LS, and femoral neck (FN) BMD, and positively correlated with osteoporotic fractures incidence (p < 0.05). Both were independent risk factors for OP, with combined SII and TMAO detection showing high diagnostic efficacy (sensitivity 94.7%, specificity 96.5%).

Conclusion

In overweight and obese patients, particularly those with a VFA ≥ 100 cm², peripheral blood SII and TMAO levels may serve as valuable biomarkers for the early diagnosis of OP, offering potential clinical utility in identifying high-risk individuals.

Links among Obesity, Type 2 Diabetes Mellitus, and Osteoporosis: Bone as a Target

Obesity, type 2 diabetes mellitus (T2DM) and osteoporosis are serious diseases with an ever-increasing incidence that quite often coexist, especially in the elderly. Individuals with obesity and T2DM have impaired bone quality and an elevated risk of fragility fractures, despite higher and/or unchanged bone mineral density (BMD). The effect of obesity on fracture risk is site-specific, with reduced risk for several fractures (e.g., hip, pelvis, and wrist) and increased risk for others (e.g., humerus, ankle, upper leg, elbow, vertebrae, and rib). Patients with T2DM have a greater risk of hip, upper leg, foot, humerus, and total fractures. A chronic pro-inflammatory state, increased risk of falls, secondary complications, and pharmacotherapy can contribute to the pathophysiology of aforementioned fractures. Bisphosphonates and denosumab significantly reduced the risk of vertebral fractures in patients with both obesity and T2DM. Teriparatide significantly lowered non-vertebral fracture risk in T2DM subjects. It is important to recognize elevated fracture risk and osteoporosis in obese and T2DM patients, as they are currently considered low risk and tend to be underdiagnosed and undertreated. The implementation of better diagnostic tools, including trabecular bone score, lumbar spine BMD/body mass index (BMI) ratio, and microRNAs to predict bone fragility, could improve fracture prevention in this patient group.

Obesity, diabetes and risk of bone fragility: How BMAT behavior is affected by metabolic disturbances and its influence on bone health

PURPOSE

Osteoporosis is a metabolic bone disease characterized by decreased bone strength and mass, which predisposes patients to fractures and is associated with high morbidity and mortality. Like osteoporosis, obesity and diabetes are systemic metabolic diseases associated with modifiable risk factors and lifestyle, and their prevalence is increasing. They are related to decreased quality of life, functional loss and increased mortality, generating high costs for health systems and representing a worldwide public health problem. Growing evidence reinforces the role of bone marrow adipose tissue (BMAT) as an influential factor in the bone microenvironment and systemic metabolism. Given the impact of obesity and diabetes on metabolism and their possible effect on the bone microenvironment, changes in BMAT behavior may explain the risk of developing osteoporosis in the presence of these comorbidities.

METHODS

This study reviewed the scientific literature on the behavior of BMAT in pathological metabolic conditions, such as obesity and diabetes, and its potential involvement in the pathogenesis of bone fragility.

RESULTS

Published data strongly suggest a relationship between increased BMAT adiposity and the risk of bone fragility in the context of obesity and diabetes.

CONCLUSION

By secreting a broad range of factors, BMAT modulates the bone microenvironment and metabolism, ultimately affecting skeletal health. A better understanding of the relationship between BMAT expansion and metabolic disturbances observed in diabetic and obese patients will help to identify regulatory pathways and new targets for the treatment of bone-related diseases, with BMAT as a potential therapeutic target.

Association between bone health and dynapenic obesity in postmenopausal women

AIM

The combination of dynapenia (age-related muscle weakness) and obesity is referred to as dynapenic obesity. We examined the associations between dynapenic obesity and cortical bone thickness and trabecular bone density.

METHODS

The participants were 797 community-dwelling postmenopausal women (with an average age of 62.5 years) who were stratified into normopenia without obesity, dynapenia without obesity (dynapenia), normopenia with obesity (obesity) and dynapenia with obesity (dynapenia obesity) groups based on their grip strength and body fat percentage. Cortical bone thickness and trabecular bone density were measured using ultrasonic bone densitometry. The participants were further divided into those with low cortical bone thickness and low trabecular bone density. Logistic regression analysis was used to identify associated factors.

RESULTS

Individuals with dynapenia (odds ratio [OR] 1.77, 95% confidence interval [CI] 1.16-2.68), obesity (OR 2.46, 95% CI 1.62-3.75) and dynapenic obesity (OR 4.07, 95% CI 2.44-6.79) all significantly increased the odds of low cortical bone thickness. Conversely, the odds of low trabecular bone density were significantly lower in the obesity group (OR 0.65, 95% CI 0.43-0.99) and dynapenic obesity group (OR 0.60, 95% CI 0.37-0.97).

CONCLUSIONS

Dynapenic obesity was found to be associated with cortical bone thinning that might compromise bone health. Postmenopausal women with dynapenic obesity might need to be closely monitored for preserving bone health. Geriatr Gerontol Int 2024; 24: 378-384.

Improved femoral micro-architecture in adult male individuals with overweight: fracture resistance due to regional specificities

BACKGROUND

It is still unclear whether femoral fracture risk is positively or negatively altered in individuals with overweight. Considering the lack of studies including men with overweight, this study aimed to analyze regional specificities in mechano-structural femoral properties (femoral neck and intertrochanteric region) in adult male cadavers with overweight compared to their normal-weight age-matched counterparts.

METHODS

Ex-vivo osteodensitometry, micro-computed tomography, and Vickers micro-indentation testing were performed on femoral samples taken from 30 adult male cadavers, divided into the group with overweight (BMI between 25 and 30 kg/m2; n = 14; age:55 ± 16 years) and control group (BMI between 18.5 and 25 kg/m2; n = 16; age:51 ± 18 years).

RESULTS

Better quality of trabecular and cortical microstructure in the inferomedial (higher trabecular bone volume fraction, trabecular thickness, and cortical thickness, coupled with reduced cortical pore diameter, p < 0.05) and superolateral femoral neck (higher trabecular number and tendency to lower cortical porosity, p = 0.043, p = 0.053, respectively) was noted in men with overweight compared to controls. Additionally, the intertrochanteric region of men with overweight had more numerous and denser trabeculae, coupled with a thicker and less porous cortex (p < 0.05). Still, substantial overweight-induced change in femoral osteodensitometry parameters and Vickers micro-hardness was not demonstrated in assessed femoral subregions (p > 0.05).

CONCLUSIONS

Despite the absence of significant changes in femoral osteodensitometry, individuals with overweight had better trabecular and cortical femoral micro-architecture implying higher femoral fracture resistance. However, the microhardness was not significantly favorable in the individuals who were overweight, indicating the necessity for further research.

Diet-Stimulated Marrow Adiposity Fails to Worsen Early, Age-Related Bone Loss

INTRODUCTION

Longitudinal effect of diet-induced obesity on bone is uncertain. Prior work showed both no effect and a decrement in bone density or quality when obesity begins prior to skeletal maturity. We aimed to quantify long-term effects of obesity on bone and bone marrow adipose tissue (BMAT) in adulthood.

METHODS

Skeletally mature, female C57BL/6 mice (n = 70) aged 12 weeks were randomly allocated to low-fat diet (LFD; 10% kcal fat; n = 30) or high-fat diet (HFD; 60% kcal fat; n = 30), with analyses at 12, 15, 18, and 24 weeks (n = 10/group). Tibial microarchitecture was analyzed by µCT, and volumetric BMAT was quantified via 9.4T MRI/advanced image analysis. Histomorphometry of adipocytes and osteoclasts, and qPCR were performed.

RESULTS

Body weight and visceral white adipose tissue accumulated in response to HFD started in adulthood. Trabecular bone parameters declined with advancing experimental age. BV/TV declined 22% in LFD (p = 0.0001) and 17% in HFD (p = 0.0022) by 24 weeks. HFD failed to appreciably alter BV/TV and had negligible impact on other microarchitecture parameters. Both dietary intervention and age accounted for variance in BMAT, with regional differences: distal femoral BMAT was more responsive to diet, while proximal femoral BMAT was more attenuated by age. BMAT increased 60% in the distal metaphysis in HFD at 18 and 24 weeks (p = 0.0011). BMAT in the proximal femoral diaphysis, unchanged by diet, decreased 45% due to age (p = 0.0002). Marrow adipocyte size via histomorphometry supported MRI quantification. Osteoclast number did not differ between groups. Tibial qPCR showed attenuation of some adipose, metabolism, and bone genes. A regulator of fatty acid β-oxidation, cytochrome C (CYCS), was 500% more abundant in HFD bone (p < 0.0001; diet effect). CYCS also increased due to age, but to a lesser extent. HFD mildly increased OCN, TRAP, and SOST.

CONCLUSIONS

Long-term high fat feeding after skeletal maturity, despite upregulation of visceral adiposity, body weight, and BMAT, failed to attenuate bone microarchitecture. In adulthood, we found aging to be a more potent regulator of microarchitecture than diet-induced obesity.

Visceral Adipose Tissue is Negatively Associated With Bone Mineral Density in NHANES 2011-2018

Context

The relationship of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) with bone mineral density (BMD) is not well established.

Objective

To examine the associations of VAT and SAT with total body BMD in a large, nationally representative population with a wide range of adiposity.

Methods

We analyzed 10 641 subjects aged 20 to 59 years in National Health and Nutrition Examination Survey 2011-2018 who had undergone total body BMD and had VAT and SAT measured by dual-energy X-ray absorptiometry. Linear regression models were fitted while controlling for age, sex, race or ethnicity, smoking status, height, and lean mass index.

Results

In a fully adjusted model, each higher quartile of VAT was associated with an average of 0.22 lower T-score (95% CI, -0.26 to -0.17, P < 0.001), whereas SAT had a weak association with BMD but only in men (-0.10; 95% CI, -0.17 to -0.04, P = 0.002). However, the association of SAT to BMD in men was no longer significant after controlling for bioavailable sex hormones. In subgroup analysis, we also found differences in the relationship of VAT to BMD in Black and Asian subjects, but these differences were eliminated after accounting for racial and ethnic differences in VAT norms.

Conclusions

VAT has a negative association with BMD. Further research is needed to better understand the mechanism of action and, more generally, to develop strategies for optimizing bone health in obese subjects.

Diabetes Mellitus Type 2 Patients with Abdominal Obesity Are Prone to Osteodysfunction: A Cross-Sectional Study

Introduction

The interaction between diabetes, obesity, and bone metabolism was drawing increasing public attention. However, the osteometabolic changes in diabetes mellitus type 2 (T2DM) patients with abdominal obesity have not been fully revealed. This study is aimed at investigating the association between abdominal obesity indices and bone turnover markers among T2DM participants.

Methods

4351 subjects were involved in the METAL study. Abdominal obesity indices included neck, waist, and hip circumference, visceral adiposity index (VAI), lipid accumulation product (LAP), waist-to-hip ratio (WHR), and Chinese visceral adiposity index (CVAI). They were applied to elucidate the nexus between β-C-terminal telopeptide (β-CTX), osteocalcin (OC), and intact N-terminal propeptide of type I collagen (P1NP).

Results

Abdominal obesity indices were strongly negatively associated with β-CTX and OC. Among males, five indices were negatively correlated with β-CTX (BMI, WC, LAP, WHR, and CVAI) and OC (BMI, NC, WC, WHR, and CVAI). There were no significant associations with P1NP. Among females, all eight indices were negatively associated with β-CTX. Seven indices were negatively related to OC (BMI, NC, WC, HC, LAP, WHR, and CVAI). The VAI was negatively correlated with P1NP.

Conclusions

The present study demonstrated that in T2DM, abdominal obesity had an obviously negative correlation with bone metabolism. Abdominal obesity indices were significantly negatively associated with skeletal destruction (β-CTX) and formation (OC). In routine clinical practice, these easily obtained indices could be used as a preliminary screening method and relevant factors for osteodysfunction incidence risk at no additional cost and may be of particular value for postmenopausal women in T2DM populations.

Cumulative Burden of Being Underweight Increases the Risk of Hip Fracture: A Nationwide Population-Based Cohort Study

(1) Background: Being underweight is a known risk factor for hip fractures. However, it is unclear whether the cumulative underweight burden affects the incidence of hip fractures. Therefore, we explored the effect of the cumulative underweight burden on the development of hip fractures; (2) Methods: In a cohort of adults aged 40 years and older, 561,779 participants who were not underweight and had no hip fractures from 2007 to 2009 were identified. The risk of hip fracture from the time of the last examination to December 2018 according to the cumulative burden of being underweight (based on 0 to 3 examinations) was prospectively analyzed; (3) Results: During follow-up (mean 8.3 ± 0.8 years), the prevalence of newly diagnosed hip fractures was 0.2%, 0.4%, 0.5%, and 0.9% among those with 0, 1, 2, and 3 cumulative underweight, respectively. The adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) of groups meeting the diagnostic criteria for underweight 1, 2, and 3 compared to 0 were 2.3 (1.6−3.3), 2.9 (1.8−4.5), and 4.5 (3.4−6.1), respectively (p for trend < 0.01); (4) Conclusions: The risk of hip fracture increased as the burden of underweight accumulated.

Relation between adipose tissue and the musculoskeletal unit in a group of postmenopausal women

Introduction

Involutional changes observed during aging increase rapidly in the postmenopausal period. These changes include body composition by affecting bone, muscle and fat tissue. A number of studies have investigated the mutual interaction between bone and muscle tissue, whereas adipose tissue had not been studied thoroughly.The aim of the present study was to assess the relation between fat tissue parameters and the musculoskeletal unit.

Material and methods

The study was conducted in a group of 120 postmenopausal women with an average age of 69 years (59-81; SD 5.3). All women had been asked to complete a questionnaire (medical history) and underwent a total body composition analysis [bone mineral density (BMD)] testing (spine and/or neck) followed by a handgrip test.

Results

The study revealed strong correlations between appendicular skeletal muscle mass index - appen.lean/height², visceral adipose tissue area (VAT) and fat/mass/height² index (r = 0.589 and 0.658 respectively; p < 0.001). The results were not supported by muscle strength (handgrip). The authors identified correlations between the bone parameters and adipose tissue but these were identified as weak or moderate (p < 0.05). Special emphasis should be placed on the relation between the trabecular bone score (TBS) and VAT area (r = -0.385, p < 0.001).

Conclusions

There is a strong dependence between muscle and adipose tissues. Despite the fact that the increase in fat is correlated with the growth of muscle tissue, it is not accompanied by better quality of the muscle (handgrip). Bone microarchitecture is more related to VAT area than neck/spine BMD.

Fat, adipokines, bone structure and bone regulatory factors associations in obesity

CONTEXT

Obese (OB) adults (BMI ≥ 30) have a higher bone mineral density (BMD) and more favourable bone microarchitecture than normal-weight (NW) adults (BMI 18.5-24.9).

OBJECTIVE

The objective of this study was to identify which fat compartments have the strongest association with bone density and bone turnover and whether biochemical factors (adipokines, hormones and bone regulators) are likely to be important mediators of the effect of obesity on bone.

DESIGN

This was a cross-sectional, observational, matched case-control study.

SETTING

Participants were recruited from the local community.

PARTICIPANTS

Two hundred healthy men and women aged 25-40 or 55-75 were recruited in individually matched OB and NW pairs. Body composition, BMD and bone microarchitecture were determined by dual-energy X-ray absorptiometry (DXA), computed tomography (CT) and high-resolution peripheral CT (HR-pQCT). Bone turnover and potential regulators such as C-terminal cross-linking telopeptide (CTX), type 1 procollagen N-terminal peptide (PINP), sclerostin, periostin, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), insulin-like growth factor 1 (IGF1), adiponectin, leptin and insulin were assessed.

MAIN OUTCOME

Planned exploratory analysis of the relationships between fat compartments, areal and volumetric BMD, bone microarchitecture, bone turnover markers and bone regulators.

RESULTS

Compared with NW, OB had lower CTX, PINP, adiponectin, IGF1, and 25OHD and higher leptin, PTH and insulin (all P < 0.05). CTX and subcutaneous adipose tissue (SAT) were the bone marker and fat compartment most consistently associated with areal and volumetric BMD. In regression models, SAT was negatively associated with CTX (P < 0.001). When leptin was added to the model, SAT was no longer associated with CTX, but leptin (P < 0.05) was negatively associated with CTX.

CONCLUSIONS

SAT is associated with lower bone resorption and properties favourable for bone strength in obesity. Leptin may be an important mediator of the effects of SAT on the skeleton.

Modifiable risk factors for bone health & fragility fractures

Osteoporosis is an ageing disorder characterised by poor microstructural architecture of the bone and an increase in the risk of fragility fractures, which often leads to hospitalisation and eventually a loss of mobility and independence. By 2050, it is estimated that more than 30 million people in Europe will be affected by bone diseases, and European hospitalisation alone can approximately cost up to 3.5 billion euros each year [1]. Although inherited variation in bone mineral density (BMD) is pre-determined by up to 85% [2], there is a window of opportunity to optimise BMD and reduce fracture risk through key modifiable lifestyle factors during the life course. An optimal diet rich in micronutrients, such as calcium, vitamin D, and potassium, has long been considered an important modifiable component of bone health, which is attributed to their direct roles within bone metabolism. Recently, there has been emerging evidence to suggest that protein and even an adequate intake of fruit and vegetables may also play an important role in improving BMD [3,4]. Maintaining a physically active lifestyle is not only protective from non-communicable diseases such as cardiovascular disease but it also has been shown to lessen the risk of fractures later in life, thereby making it an imperative modifiable factor for bone health, particularly as it also supports peak bone mass attainment during childhood/adolescence and can facilitate the maintenance of bone mass throughout adulthood [5]. Other key lifestyle factors that could be potentially modified to reduce the risk of osteoporosis or osteoporotic fractures later in life include smoking status, alcohol intake, and body composition [6]. Therefore, the principle aim of this review is to highlight the recent evidence pertaining to modifiable lifestyle factors that contribute to optimal bone health and the prevention of fragility fractures in later life.

Association between the appendicular lean mass index or handgrip strength and bone mineral density in patients undergoing peritoneal dialysis

Background: Few studies have investigated the association between muscle mass and bone mineral density (BMD) in patients undergoing peritoneal dialysis (PD). We aimed to investigate the association between muscle mass or strength and BMD in patients undergoing PD. Methods: The data of all prevalent PD cases at a tertiary medical center between September 2017 and November 2020 were collected. Among all patients, 199 patients undergoing PD were finally analyzed. Baseline measurements including handgrip strength (HGS), appendicular lean mass (ALM) index, and BMD were obtained during a peritoneal membrane equilibration test. Patients with a T-score of ≤ -2.5 were categorized into the low BMD group. Results: The number of male patients was 113 (56.8%). Significant differences were observed in various indices, such as BMD, body composition parameters, and laboratory findings, between male and female patients. There was a stronger association between BMD and ALM index than between BMD and HGS in male patients (r = 0.432 and P < 0.001). The association between BMD and HGS was more definitive in female patients than in male patients (r = 0.357 and P = 0.001). Univariate and mutivariate linear regression and AUROC analyses showed similar trends those obtained in correlation analyses. Conclusion: The present study demonstrated that BMD is associated with the ALM index in male patients and with HGS in female patients undergoing PD.

Osteosarcopenia and trabecular bone score in patients with type 2 diabetes mellitus

OBJECTIVE

To evaluate the prevalence of osteosarcopenia and the association of osteosarcopenia with trabecular bone score (TBS) in a group of patients with type 2 diabetes mellitus(T2DMG) compared with a paired control group (CG).

METHODS

Cross-sectional study with men and women ≥ 50 years recruited by convenience. Patients in both groups answered questionnaires and underwent evaluation of bone mineral density (BMD), handgrip strength (HGS), and TBS. The T2DMG also underwent a gait speed (GS) test. Sarcopenia was defined as low lean mass plus low HGS or GS according to the Foundation for the National Institute of Health Sarcopenia Project, and osteosarcopenia was deemed present when sarcopenia was associated with osteopenia, osteoporosis, or low-energy trauma fractures.

RESULTS

The T2DMG (n = 177) and CG (n = 146) had, respectively, mean ages of 65.1 ± 8.2 years and 68.8 ± 11.0 years and 114 (64.4%) and 80 (54.7%) women. T2DMG versus the CG had higher rates of osteosarcopenia (11.9% versus 2.14%, respectively, p = 0.010), sarcopenia (12.9% versus 5.4%, respectively, p < 0.030), and fractures (29.9% versus 18.5%, respectively, p = 0.019), and lower HGS values (24.4 ± 10.3 kg versus 30.9 ± 9.15 kg, respectively, p < 0.001), but comparable BMD values. Mean TBS values were 1.272 ± 0.11 and 1.320 ± 0.12, respectively (p = 0.001). On multivariate analysis, age, greater waist circumference, fractures, and osteoporosis increased the risk of degraded TBS. Osteosarcopenia was associated with diabetes complications (p = 0.03), calcium and vitamin D supplementation (p = 0.01), and all components of osteosarcopenia diagnosis (p < 0.05).

CONCLUSION

Compared with the CG, the T2DMG had a higher prevalence of osteosarcopenia, sarcopenia, and fractures and lower bone quality assessed by TBS.

Effect of body mass index on vertebral and hip fractures in older people and differences according to sex: a retrospective Japanese cohort study

OBJECTIVES

The purpose of this study was to investigate the incidence of vertebral and hip fractures in the older people and to clarify the relationship between these fractures and body mass index (BMI) along with the impact of sex differences.DesignThis was a retrospective cohort study.SettingWe used administrative claims data between April 2010 and March 2018.

PARTICIPANTS

Older people aged ≥75 years who underwent health examinations in 2010 and were living in the Fukuoka Prefecture, Japan were included in the study. A total of 24 691 participants were included; the mean age was 79.4±4.3 years, 10 853 males and 13 838 females, and an the mean duration of observation was 6.9±1.6 years.

PRIMARY AND SECONDARY OUTCOME MEASURES

We estimated the incidence of vertebral and hip fractures by BMI category (underweight: <18.5 kg/m², normal weight: 18.5-24.9 kg/m², overweight and obese: ≥25.0 kg/m²) using a Kaplan-Meier curve in males and females and determined fracture risk by sex using Cox proportional hazards regression analyses.

RESULTS

The incidence of vertebral and hip fractures was 16.8% and 6.5%, respectively. The cumulative incidence of vertebral and hip fracture at the last observation (8 years) in each BMI groups (underweight/normal weight/overweight and obese) estimated using the Kaplan-Meier curve was 14.7%/10.4%/9.0% in males and 24.9%/23.0%/21.9% in females, and 6.3%/2.9%/2.4% in males and 14.1%/9.0%/8.1% in females, respectively, and both fractures were significantly higher in underweight groups regardless of sex. Multivariable Cox proportional hazards models showed that underweight was a significant risk factor only in males for vertebral fractures and in both males and females for hip fractures.

CONCLUSION

Underweight was associated with fractures in the ageing population, but there was a sex difference in the effect for vertebral fractures.

Low serum levels of bone turnover markers are associated with perirenal fat thickness in patients with type 2 diabetes mellitus

BACKGROUND

Obesity is known as a common risk factor for osteoporosis and type 2 diabetes mellitus (T2DM). Perirenal fat, surrounding the kidneys, has been reported to be unique in anatomy and biological functions. This study aimed to explore the relationship between perirenal fat and bone metabolism in patients with T2DM.

METHODS

A total of 234 patients with T2DM were recruited from September 2019 to December 2019 in the cross-sectional study. The biochemical parameters and bone turnover markers (BTMs) were determined in all participants. Perirenal fat thickness (PrFT) was performed by ultrasounds via a duplex Doppler apparatus. Associations between PrFT and bone metabolism index were determined via correlation analysis and regression models.

RESULTS

The PrFT was significantly correlated with β-C-terminal telopeptides of type I collagen (β-CTX) (r = -0.14, P < 0.036), parathyroid hormone (iPTH) (r = -0.18, P ≤ 0.006), and 25 hydroxyvitamin D (25-OH-D) (r = -0.14, P = 0.001). Multivariate analysis confirmed that the association of PrFT and β-CTX (β = -0.136, P = 0.042) was independent of other variables.

CONCLUSION

This study showed a negative and independent association between PrFT and β-CTX in subjects with T2DM, suggesting a possible role of PrFT in bone metabolism. Follow-up studies and further research are necessary to validate the associations and to elucidate the underlying mechanisms.

[The role of adipose tissue and laboratory predictors of primary osteoporosis.]

The purpose of this work was to determine the information content of alkaline phosphatase (ALP), total calcium (Ca) as predictors for the diagnosis of osteoporosis. By laboratory methods, 2451 people were divided into two groups according to the presence/absence of metabolic syndrome (MetS+ / MetS-): 1946 women (MetS- 1119, MetS+ 827) and 505 men (MetS- 264, MetS+ 241). Patients with laboratory signs of liver pathology are excluded. In women: MetS+ levels of ALP and Ca significantly differ from MetS- (p<0.0001), no differences were found for men. ALP synchronously change the indicators of TG, HDL, LDL, ALT, AST, Ca, demonstrating a positive relationship (p<0.001), the indicators do not exceed the threshold values. MetS- women in pre- and postmenopausal women significantly differ in ALP: 63.90 E / l vs 79.10 E / l (p<0.0001).

Association between Visceral Fat and Bone Mineral Density in Both Male and Female Patients with Adult Growth Hormone Deficiency

Aim

Adult growth hormone deficiency (AGHD) is associated with an increased risk of fractures. The interactions between various body composition and bone are known to be complex in nature. However, very few studies have examined this crosstalk in AGHD. In this study, we sought to investigate the relationship between various parameters of body composition and bone mineral density (BMD) as well as determine the role of visceral fat in determining the bone mass in patients with AGHD.

Methods

We conducted a cross-sectional study on 57 patients with AGHD. Anthropometry, biochemistry, and analysis of body composition and BMD were performed according to standard protocols. Male and female patients were classified into those with osteoporosis and those without osteoporosis (normal subjects and patients with osteopenia). Further, we analyzed the correlation between the BMD and measurements obtained for various body composition parameters in male and female AGHD patients.

Results

Our findings indicated that among female AGHD patients, those with osteoporosis had a significantly higher levels of fat mass (FM) and visceral adipose tissue mass (VATM) (both, P < 0.05) than those without osteoporosis. Further, Pearson correlation analysis showed that the values of age, body mass index (BMI), FM, and VATM correlated negatively with BMD in women with AGHD (all P < 0.05); however, this association was not noted in men. After adjusting for the other covariates, VATM was found to be independently correlated with the BMD in female patients with AGHD.

Conclusions

A close correlation was noted between VATM and BMD in female patients with AGHD.

Gender-Specific Body Composition Relationships between Adipose Tissue Distribution and Peak Bone Mineral Density in Young Chinese Adults

Background

The relationships between adipose tissue distribution and peak bone mineral density (BMD) in young adults are still unclear. The aim of this study was to investigate the body composition associations between fat mass (FM), lean mass (LM), regional adipose tissue distribution, and peak BMD across a cohort of young Chinese adults.

Methods

Dual-energy X-ray absorptiometry (DXA) scans were performed on 786 men and 825 women aged from 20 to 40 years old to measure the markers for whole-body LM, FM, and BMD in the lumbar spine (LS), femoral neck (FN), and total hip (TH) areas. The android/gynoid FM ratio (A/G FMR) based on the DXA scans was calculated as an indicator of adipose tissue distribution. Pearson's correlation and multivariable linear regression analyses were conducted to determine the body composition relationships between adipose tissue distribution and BMD of each skeletal site.

Results

The body composition characteristics were different in young males and females: a higher body FM percentage was found in females, while males had higher LM and A/G FMR. The markers for WBLM and WBFM had significant positive correlations with BMD among the linear regression analyses in both genders, while the relationships between A/G FMR and BMD were different in males and females; significant inverse associations were showed in all skeletal sites for women (standard β ranged from -0.266 to -0.170, P < 0.001 for all), but no significant relationships were found in men except for an inverse association in the LS skeletal site (standard β with -0.115, P = 0.016).

Conclusions

In this sample of young Chinese adults, both whole-body lean mass and fat mass had significant positive relationships with BMD in both genders. The A/G FMR, as an indicator of central adipose tissue distribution, was inversely associated with BMD, especially in females.

Inverse association of plasma leptin with cortical thickness at distal radius determined with a quantitative ultrasound device in patients with type 2 diabetes mellitus

AIMS/INTRODUCTION

Osteoporosis is known to be intimately related to sympathetic nerve activity. We examined the relationship of plasma leptin with cortical and trabecular bone components in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

The present cross-sectional study included 182 type 2 diabetes mellitus patients (93 men, 89 women). Cortical thickness (CoTh) and trabecular bone mineral density (BMD) were determined at the 5.5% distal radius using an LD-100 ultrasonic bone densitometry device. Plasma leptin along with physical and laboratory measurements was simultaneously determined.

RESULTS

Plasma leptin, but not body mass index (BMI), was inversely correlated with CoTh (ρ = -0.487, P < 0.001), while BMI, but not plasma leptin, was positively correlated with trabecular BMD (ρ = 0.369, P < 0.001). In multivariable regression analysis, after adjustments for age, sex, duration of diabetes, glycated hemoglobin A1c, albumin, estimated glomerular filtration rate, parathyroid hormone and handgrip strength, plasma leptin was inversely associated with CoTh (β = -0.258, P < 0.001), but not trabecular BMD. Furthermore, plasma leptin level retained a significant association with CoTh after further adjustment for BMI (β = -0.237, P < 0.001) and BMI plus waist-to-hip ratio (β = -0.243, P < 0.001). In contrast, the "sex × leptin" interaction was not significant (P = 0.596).

CONCLUSIONS

Leptin level in plasma, independent of BMI and BMI plus waist-to-hip ratio, was shown to be inversely associated with CoTh, but not trabecular BMD, suggesting that hyperleptinemia resulting from obesity might contribute to cortical porosis in patients with type 2 diabetes mellitus.

Longitudinal Changes in Muscle Mass and Strength, and Bone Mass in Older Adults: Gender-Specific Associations Between Muscle and Bone Losses

Background

The aims of this study were to investigate the longitudinal changes in muscle and bone with aging, and to clarify the muscle-bone relationships.

Methods

In a community-based prospective study, a total of 172 men and 165 women aged ≥ 65 years who had performed body composition analysis and bone mineral density (BMD) by dual-energy x-ray absorptiometry at baseline and 5-year follow-up evaluations were included.

Results

The rate of BMD loss in total hip was significantly associated with baseline legs lean mass and loss rate of leg strength, but not with the rate of muscle mass losses in men (r = .205 in leg lean mass, r = .170 in loss rate of leg muscle strength, p < .05 respectively). However, in women, it was significantly correlated with the rate of leg lean mass loss, but not with baseline values, and the rate of loss in leg muscle strength (r = .169 in the rate of loss in leg lean mass, r = .246 in the rate of loss in leg muscle strength, p < .05 respectively). In multivariate analyses, the rates of decrease in leg muscle strength showed independent positive associations with loss in total hip BMD in both men and women (β = 0.023 for men and β = 0.045 for women, both p < .05 respectively).

Conclusion

There was a gender difference in muscle and bone mass changes with aging, and muscle-bone interactions as well. However, a longitudinal change in muscle strength was the most significant independent factor associated with bone loss for both genders.

Obesity and Bone Health Revisited: A Mendelian Randomization Study for Koreans

Epidemiologic studies have replicated positive associations between obesity and bone health, but their mechanisms are still debatable. We aimed to scrutinize an association between bone health and obesity using genetic instrumental variables (IVs) with the distinction of general versus abdominal obesity. We selected independent IVs of body mass index (BMI) and BMI-adjusted waist circumference (aWC, a proxy of a central fat distribution) by combining novel genomewide searches from the Korean Genome Epidemiology Study (KoGES) consortium and existing reports. We evaluated the associations of obesity indices with bone health measures for weight-bearing and non-weight-bearing bones, applying standard Mendelian randomization analyses. The IVs for BMI and aWC selected from KoGES cohort studies (n = 14,389) explained its own trait only, negating the mutual correlation at the phenotypic level. Two-stage least squares analyses using an independent cohort study (n = 2507, mean age = 44.4 years, men = 44.3%) showed that BMI but not aWC was positively associated with bone mineral density (BMD for weight-bearing bones: 0.063 ± 0.016 g/cm² per one standard deviation increase in BMI), implying the fat distribution might be neutral. The association was weaker for non-weight-bearing bones (BMI on BMD: 0.034 ± 0.011 g/cm² ), and for postmenopausal women the association was absent. Obesity increased both bone area and bone mineral content (BMC) to a lesser degree, but the increase in BMC was not evident for menopausal women. When we stratified the weight into lean body mass and fat mass, the increase in BMD was more evident for lean body mass, and fat mass showed a beneficial role only for men and premenopausal women. Our findings suggest that bone health might gain little from obesity, if any, through its added weight, and other means to prevent bone loss would be essential for postmenopausal women. © 2019 American Society for Bone and Mineral Research.

Physical Activity Across Adulthood and Bone Health in Later Life: The 1946 British Birth Cohort

Leisure-time physical activity (LTPA) is widely recommended for the prevention of osteoporosis and fractures in older populations. However, whether the beneficial effects of LTPA on bone accumulate across life and are maintained even after reduction or cessation of regular PA in later life is unknown. We examined whether LTPA across adulthood was cumulatively associated with volumetric and areal bone mineral density (vBMD, aBMD) at ages 60 to 64 and whether associations were mediated by lean mass. Up to 1498 participants from the Medical Research Council National Survey of Health and Development were included in analyses. LTPA was self-reported at ages 36, 43, 53, and 60 to 64, and responses summed to generate a cumulative score (range 0 = inactive at all four ages to 8 = most active at all four ages). Total and trabecular vBMD were measured at the distal radius using pQCT and aBMD at the total hip and lumbar spine (L1 to L4) using DXA. Linear regression was used to test associations of the cumulative LTPA score with each bone outcome. After adjustment for height and weight, a 1-unit increase in LTPA score (95% CI) in men was associated with differences of 1.55% (0.78% to 2.31%) in radial trabecular vBMD, 0.83% (0.41% to 1.25%) in total hip aBMD, and 0.97% (0.44% to 1.49%) in spine aBMD. Among women, positive associations were seen for radial trabecular vBMD and total hip aBMD, but only among those of greater weight (LTPA × weight interaction p ≤ 0.01). In men, there was evidence to suggest that lean mass index may partly mediate these associations. These findings suggest that there are cumulative benefits of LTPA across adulthood on BMD in early old age, especially among men. The finding of weaker associations among women suggests that promotion of specifıc types of LTPA may be needed to benefit bone health in women. © 2018 The Authors. Journal of Bone and Mineral Research Published by Wiley Periodicals, Inc.

Adipose tissue depot volume relationships with spinal trabecular bone mineral density in African Americans with diabetes

Changes in select adipose tissue volumes may differentially impact bone mineral density. This study was performed to assess cross-sectional and longitudinal relationships between computed tomography-determined visceral (VAT), subcutaneous (SAT), inter-muscular (IMAT), and pericardial adipose tissue (PAT) volumes with respective changes in thoracic vertebral and lumbar vertebral volumetric trabecular bone mineral density (vBMD) in African Americans with type 2 diabetes. Generalized linear models were fitted to test relationships between baseline and change in adipose volumes with change in vBMD in 300 African American-Diabetes Heart Study participants; adjustment was performed for age, sex, diabetes duration, study interval, smoking, hypertension, BMI, kidney function, and medications. Participants were 50% female with mean ± SD age 55.1±9.0 years, diabetes duration 10.2±7.2 years, and BMI 34.7±7.7 kg/m². Over 5.3 ± 1.4 years, mean vBMD decreased in thoracic/lumbar spine, while mean adipose tissue volumes increased in SAT, IMAT, and PAT, but not VAT depots. In fully-adjusted models, changes in lumbar and thoracic vBMD were positively associated with change in SAT (β[SE] 0.045[0.011], p<0.0001; 0.40[0.013], p = 0.002, respectively). Change in thoracic vBMD was positively associated with change in IMAT (p = 0.029) and VAT (p = 0.016); and change in lumbar vBMD positively associated with baseline IMAT (p<0.0001). In contrast, vBMD was not associated with change in PAT. After adjusting for BMI, baseline and change in volumes of select adipose depots were associated with increases in thoracic and lumbar trabecular vBMD in African Americans. Effects of adiposity on trabecular bone appear to be site-specific and related to factors beyond mechanical load.

Role of Fat and Bone Biomarkers in the Relationship Between Ethnicity and Bone Mineral Density in Older Men

Osteoporosis is an important health issue for older adults, and has been relatively understudied in older men. This study aimed to examine ethnic differences in bone mineral density (BMD), and elucidate the role of bone turnover markers (BTMs), fat and fat biomarkers on these ethnic differences. BMD at the lumbar spine and femoral neck, marrow fat at femoral neck, visceral adipose tissue (VAT) and subcutaneous adipose tissue, bone and fat biomarkers were evaluated in 120 healthy men aged ≥ 60 years. Indians had higher BMD values compared to Chinese at the lumbar spine (β = 20.336, SE = 4.749, p < 0.001) and the femoral neck (e ^β  = 1.105, SE = 0.032, p < 0.001), after adjusting for BTMs, fat composition and lifestyle choices. Marrow fat, VAT and adiponectin were independent predictors of BMD. However, these factors did not explain the lower BMD observed in older Chinese men. Our findings suggest that older Chinese men are at significant risk of osteoporotic fractures due to lower BMD. Fat appears to be a key factor associated with lower BMD, and warrants further longitudinal studies to elucidate the complex interactions between adipose tissue and bone strength.

Appendicular and whole body lean mass outcomes are associated with finite element analysis-derived bone strength at the distal radius and tibia in adults aged 40years and older

PURPOSE

The purpose of this cross-sectional study was to determine how appendicular lean mass index (ALMI), and whole body lean (LMI) and fat mass indices (FMI) associate with estimated bone strength outcomes at the distal radius and tibia in adults aged 40 years and older.

METHODS

Dual energy X-ray absorptiometry (DXA) scans were performed to determine body composition, including whole body lean and fat mass, and appendicular lean mass. ALMI (appendicular lean mass/height²), LMI (lean tissue mass/height²) and FMI (fat mass/height²) were calculated. High-resolution peripheral quantitative computed tomography (HRpQCT) scans were performed to assess bone structural properties at the distal radius and tibia. Using finite element analysis, failure load (N), stiffness (N/mm), ultimate stress (MPa), and cortical-to-trabecular load ratio were estimated from HRpQCT scans. The associations between body composition (ALMI, LMI, FMI) and estimated bone strength were examined using bivariate and multivariable linear regression analyses adjusting for age, sex, and other confounding variables.

RESULTS

In 197 participants (127 women; mean±SD, age: 69.5±10.3y, body mass index: 27.95±4.95kg/m², ALMI: 7.31±1.31kg/m²), ALMI and LMI were significantly associated with failure load at the distal radius and tibia (explained 39%-48% of the variance) and remained significant after adjusting for confounding variables and multiple testing (R²=0.586-0.645, p<0.001). ALMI, LMI, and FMI did not have significant associations with ultimate stress in our multivariable models. FMI was significantly associated with cortical-to-trabecular load ratio at the distal radius and tibia (explained 6%-12% of the variance) and remained significant after adjusting for confounders and multiple testing (R²=0.208-0.243, p<0.001). FMI was no longer significantly associated with failure load after adjusting for confounders.

CONCLUSION

These findings suggest that ALMI and LMI are important determinants of estimated bone strength, particularly failure load, at the distal radius and tibia, and may contribute to preservation of bone strength in middle-to-late adulthood.

The Relationship Between Body Composition and Bone Quality Measured with HR-pQCT in Peritoneal Dialysis Patients

BACKGROUND

Bone is known to be impaired in chronic kidney disease and dialysis patients. Recent studies have shown that body composition (fat mass and lean mass) may impact bone health. Some of these effects may be related to mediators that are secreted by adipose tissue.

METHODS

The aim of this study was to evaluate the association between body composition (dual x-ray absorptiometry [DEXA]) and adipokines (leptin, adiponectin), with bone density and microarchitecture assessed with high-resolution peripheral quantitative computed tomography (HR-pQCT) in chronic peritoneal dialysis (PD) patients in a single-center prospective study.

RESULTS

Twenty-three patients with a median age of 61 years and body mass index (BMI) of 27 kg/m² were recruited. On univariate analysis, age was negatively associated with total volumetric bone mineral density (vBMD) (r = -0.75, p < 0.01), cortical vBMD (r = -0.85, p < 0.01), and cortical thickness (r = -0.71, p < 0.01). There was a negative association between leptin and cortical thickness (r = -0.48, p = 0.021). Fat mass (FM) was negatively correlated with cortical thickness (r = -0.52, p = 0.012). No association was found between bone parameters and dialysis duration, serum insulin, intact parathyroid hormone, osteocalcin, and adiponectin. The short dialysis vintage could in part explain the lack of correlation with bone parameters. In multivariate analysis, FM was significantly and negatively correlated with total vBMD, cortical and trabecular thickness.

CONCLUSIONS

These data suggest that FM is negatively associated with bone quality in PD patients, supporting a relation between body composition and bone that is independent from other dialysis-associated complications. The relative contribution of the different fat deposits (visceral versus subcutaneous) needs to be assessed in future studies.

Obesity, Type 2 Diabetes and Bone in Adults

In an increasingly obese and ageing population, type 2 diabetes (T2DM) and osteoporotic fracture are major public health concerns. Understanding how obesity and type 2 diabetes modulate fracture risk is important to identify and treat people at risk of fracture. Additionally, the study of the mechanisms of action of obesity and T2DM on bone has already offered insights that may be applicable to osteoporosis in the general population. Most available evidence indicates lower risk of proximal femur and vertebral fracture in obese adults. However the risk of some fractures (proximal humerus, femur and ankle) is higher, and a significant number fractures occur in obese people. BMI is positively associated with BMD and the mechanisms of this association in vivo may include increased loading, adipokines such as leptin, and higher aromatase activity. However, some fat depots could have negative effects on bone; cytokines from visceral fat are pro-resorptive and high intramuscular fat content is associated with poorer muscle function, attenuating loading effects and increasing falls risk. T2DM is also associated with higher bone mineral density (BMD), but increased overall and hip fracture risk. There are some similarities between bone in obesity and T2DM, but T2DM seems to have additional harmful effects and emerging evidence suggests that glycation of collagen may be an important factor. Higher BMD but higher fracture risk presents challenges in fracture prediction in obesity and T2DM. Dual energy X-ray absorptiometry underestimates risk, standard clinical risk factors may not capture all relevant information, and risk is under-recognised by clinicians. However, the limited available evidence suggests that osteoporosis treatment does reduce fracture risk in obesity and T2DM with generally similar efficacy to other patients.

Body Composition is Associated With Bone and Glucose Metabolism in Postmenopausal Women With Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is associated with increased fracture risk; the underlying mechanism remains unexplained. This study aimed to investigate the relationships between body composition and bone and glucose metabolism in postmenopausal women with T2DM. Dual-energy X-ray absorptiometry was used to measure bone mineral density (BMD) and body composition. A total of 68 postmenopausal women with T2DM and 71 controls were eligible for the study. In contrast to normal BMD in T2DM, a similar prevalence of low-trauma fractures was observed in both groups. T2DM women had significantly higher Trunk fat% and A/G ratio and significantly lower Legs LM% and Legs FM%. Legs LM% was significantly lower in fractured T2DM group and negatively correlated with glycaemia and HbA1c (p<0.01). Serum osteocalcin was significantly lower in T2DM and inversely correlated with FM%, Trunk FM% and A/G ratio (p<0.01) and positively correlated with Legs FM% and total LM% (p<0.05). In conclusion, abdominal obesity and decrease in muscle mass may contribute to low bone formation in T2DM women. Further research is needed to unravel underlying pathophysiological mechanisms and to determine whether maintenance of muscle mass, especially in the lower extremities and/or reduction of central fat mass can prevent fractures.

Bone Mineral Density and Body Composition are Associated with Circulating Angiogenic Factors in Post-menopausal Women

Lean mass (LM) and fat mass (FM) are closely related to bone mass (BM) in post-menopausal women, although their relative importance is unclear. Angiogenic factors which control angiogenesis may influence BM, LM and FM. The aim of the study was to compare the contribution of LM and FM to bone mineral density (BMD) and the association between these tissues and circulating angiogenic factors. The study population comprised of 392 post-menopausal women aged mean [SD] 61.8 [6.4] years. BMD was measured at the lumbar spine (LS), neck of femur and total hip (TH) by dual-energy X-ray absorptiometry (DXA). DXA scan was also used to determine LM and FM. Angiopoietin-1 and 2 (ANG-1, ANG-2) were measured by sandwich enzyme-linked immunosorbent assay. Following adjustment for confounders, significant positive independent associations were seen between LM with BMD at all skeletal sites (TH: p < 0.0001) and FM with BMD at the hip sites (TH: p = 0.004). When BMD and LM were regressed against the angiogenic factors, positive associations were seen between ANG-2 with LM (p = 0.002) and LS BMD (p = 0.05). Negative associations were observed between the ratio of ANG-1/ANG-2 with LS BMD (p = 0.014), TH BMD (p = 0.049) and LM (p = 0.029). FM and fat distribution (android/gynoid fat ratio) were negatively associated with ANG-1 (p = 0.006) and ANG-2 (p = 0.004), respectively. ANG-1 and ANG-2 may be involved in the maintenance of bone, muscle and fat mass.

Age and Sex Differences in Body Mass Index as a Predictor of Hip Fracture: A NOREPOS Study

It is unclear whether very high body mass index (BMI; weight (kg)/height (m)²) lowers risk of hip fracture. Our objectives in this study were 1) to examine the association between BMI and subsequent hip fracture according to sex and age and 2) to explore whether the importance of known risk factors varied across BMI. We followed 61,787 participants (29,511 female and 32,276 male) in the Cohort of Norway (ages 50-79 years at baseline in 1994-2003) with regard to hip fracture. BMI was calculated from measured height and weight. During a median follow-up period of 8.4 years, 1,603 women and 951 men suffered a hip fracture. Hazard ratios for hip fracture and associated 95% confidence intervals were estimated. After adjustment for potential confounders, women with BMI <22 had a hazard ratio of 1.38 (95% confidence interval (CI): 1.18, 1.60) for hip fracture, as compared with women with BMI 22-24.9; and women with BMI ≥30 had a hazard ratio of 0.57 (95% CI: 0.49, 0.66). Corresponding results in men were hazard ratio = 1.66 (95% CI: 1.35, 2.05) and hazard ratio = 0.77 (95% CI: 0.62, 0.96), respectively. Below age 70 years, there was no further decrease in fracture risk at BMIs of 25 or more, while in women aged 70-79 years, the risk continued to decrease with increasing BMI. The associations between risk factors and hip fracture were similar in strength across BMI strata.

Impact of obesity on bone mass throughout adult life: Influence of gender and severity of obesity

BACKGROUND

Obesity improves areal bone mineral density (aBMD). However, it is unknown whether gender, ageing or the severity of obesity could modulate this effect and whether different bone sites are similarly affected.

OBJECTIVE

The aim of this observational study was to model the aBMD variation in obese patients from peak bone period to old age according to gender, bone localisation and severity of obesity.

SUBJECTS AND METHODS

Five hundred and four obese patients (363 women, 72%) with a mean BMI of 38.5 ± 6.0 kg/m2, aged from 18.1 to 81.9 years (mean age 49.6 ± 14.6 years) were recruited. The whole body (WB), hip, lumbar spine (L1–L4) and one-third radius aBMDs were determined using dual-energy x-ray absorptiometry (DXA).

RESULTS

Z-scores were significantly increased, above the age- and gender-related mean, both for women and men at WB (respectively 0.79 SD and 0.32 SD), hip (1.09 SD and 1.06 SD), one-third radius (1.70 SD and 0.45 SD) and L1–L4 levels (0.86 SD for women only). The improvement of Z-scores was significantly more marked in women compared to men at all bone sites, hip excepted. Furthermore, differences compared with normal values were significantly accentuated by ageing, without noticeable gender effect. In women, regardless of BMI and bone site, Z-scores were higher than normal values, this difference being most marked at WB, L1–L4 and hip levels for obese patients with a BMI above 40 kg/m2. Lean mass, but not fat mass, was independently associated with aBMD in men and women.

CONCLUSION

This study demonstrated for the first time that obesity induces an improvement of aBMD, which is modulated by bone site location, severity of obesity, age and gender. The accentuation of peak bone mass combined with a reduction of bone loss rate with ageing may explain why obese patients present a lower prevalence of osteoporosis.

Skeletal Metabolism, Fracture Risk, and Fracture Outcomes in Type 1 and Type 2 Diabetes

Fracture risk is significantly increased in both type 1 and type 2 diabetes, and individuals with diabetes experience worse fracture outcomes than normoglycemic individuals. Factors that increase fracture risk include lower bone mass in type 1 diabetes and compromised skeletal quality and strength despite preserved bone density in type 2 diabetes, as well as the effects of comorbidities such as diabetic macro- and microvascular complications. In this Perspective, we assess the developing scientific knowledge regarding the epidemiology and pathophysiology of skeletal fragility in patients with diabetes and the emerging data on the prediction, treatment, and outcomes of fractures in individuals with type 1 and type 2 diabetes.

BMI and BMD: The Potential Interplay between Obesity and Bone Fragility

Recent evidence demonstrating an increased fracture risk among obese individuals suggests that adipose tissue may negatively impact bone health, challenging the traditional paradigm of fat mass playing a protective role towards bone health. White adipose tissue, far from being a mere energy depot, is a dynamic tissue actively implicated in metabolic reactions, and in fact secretes several hormones called adipokines and inflammatory factors that may in turn promote bone resorption. More specifically, Visceral Adipose Tissue (VAT) may potentially prove detrimental. It is widely acknowledged that obesity is positively associated to many chronic disorders such as metabolic syndrome, dyslipidemia and type 2 diabetes, conditions that could themselves affect bone health. Although aging is largely known to decrease bone strength, little is yet known on the mechanisms via which obesity and its comorbidities may contribute to such damage. Given the exponentially growing obesity rate in recent years and the increased life expectancy of western countries it appears of utmost importance to timely focus on this topic.

Assessment of Fat distribution and Bone quality with Trabecular Bone Score (TBS) in Healthy Chinese Men

Whether fat is beneficial or detrimental to bones is still controversial, which may be due to inequivalence of the fat mass. Our objective is to define the effect of body fat and its distribution on bone quality in healthy Chinese men. A total of 228 men, aged from 38 to 89 years, were recruited. BMD, trabecular bone score (TBS), and body fat distribution were measured by dual-energy X-ray absorptiometry. Subcutaneous and visceral fat were assessed by MRI. In the Pearson correlation analysis, lumbar spine BMD exhibited positive associations with total and all regional fat depots, regardless of the fat distribution. However, the correlation disappeared with adjusted covariables of age, BMI, HDL-C, and HbA1c%. TBS was negatively correlated with fat mass. In multiple linear regression models, android fat (and not gynoid, trunk, or limbs fat) showed significant inverse association with TBS (β = −0.611, P < 0.001). Furthermore, visceral fat was described as a pathogenic fat harmful to TBS, even after adjusting for age and BMI (β = −0.280, P = 0.017). Our findings suggested that body fat mass, especially android fat and visceral fat, may have negative effects on bone microstructure; whereas body fat mass contributes to BMD through mechanical loading.

Regional body fat depots differently affect bone microarchitecture in postmenopausal Korean women

SUMMARY

In a prospective community-based cohort study, we investigated the relationship between trabecular bone score (TBS) and regional fat depots in 1474 Korean postmenopausal women. TBS was positively related with subcutaneous fat and negatively related with visceral fat.

INTRODUCTION

The effect of fat distribution (visceral/subcutaneous) on bone quality or microarchitecture has rarely been investigated due to measurement difficulty. We aimed to investigate the relationship between TBS reflecting bone microarchitecture and regional fat depots in Korean women.

METHODS

Cross-sectional data evaluation was made from subjects participating in an ongoing prospective community-based cohort study since 2001. A total of 1474 postmenopausal women in the Ansung cohort were analyzed. Regional body fat mass, bone mineral density (BMD) at the lumbar spine, and total hip and lumbar spine TBS were measured by dual energy X-ray absorptiometry (DXA).

RESULTS

In an age-adjusted partial correlation analysis, TBS was not associated with total fat mass, but negatively associated with trunk fat mass. However, TBS was positively related with leg (r = 0.102, P < 0.05) and gynoid fat mass (r = 0.086, P < 0.05) and negatively related with android fat mass (r = -0.106; P < 0.05). In linear regression models controlling age, BMI, and physical activity, android fat was inversely associated with TBS (β = -0.595, P < 0.001), whereas gynoid fat was positively associated with TBS (β = 0.216, P < 0.001). Lumbar spine and total hip BMDs revealed positive associations with total and all regional fat depots regardless of fat distribution.

CONCLUSION

Our findings suggest that relatively large visceral fat and small subcutaneous fat may have a detrimental effect on TBS, a bone microarchitecture index.

Impact of Body Mass Index on the Outcomes of Open Reduction for Mandibular Fractures

PURPOSE

Little is known about the impact of body mass index (BMI) on the postoperative outcomes of open reduction for mandibular fractures. The aim of this study was to investigate the relationship between BMI and short-term outcomes of surgery for mandibular fractures.

MATERIALS AND METHODS

We searched the Japanese Diagnosis Procedure Combination database to identify patients who underwent open reduction for mandibular fractures from July 2010 to March 2013. BMI was divided into three groups: less than 18.5 kg/m(2) (underweight), 18.5 to 24.9 kg/m(2) (normal weight), and 25 kg/m(2) or greater (overweight). The outcomes included postoperative complication rates, duration of anesthesia, length of stay, and total costs. We analyzed the relationships between BMI and the outcomes by multivariable regression analyses.

RESULTS

We analyzed 309 patients who underwent open reduction for mandibular fractures during the study period. The group with a BMI of 25 kg/m(2) or greater had a significantly longer hospital stay (3.8 days; 95% confidence interval, 0.5 to 7.1 days, P = .03) than the group with a normal BMI. BMI was not significantly associated with duration of anesthesia, postoperative complication rates, or total costs.

CONCLUSIONS

Regarding open reduction for mandibular fractures, overweight status may be associated with a prolonged length of stay, but may have little impact on operating time, postoperative morbidity, or overall costs.

Body composition, lung function, and prevalent and progressive bone deficits among adults with cystic fibrosis

INTRODUCTION

Cystic fibrosis (CF) is associated with osteoporosis and incident fracture. This study assessed independent predictors of baseline and 2-year changes in bone mineral density (BMD) in adults with CF.

METHODS

Sixty-four adult patients with CF, ages 18-57, were recruited from the Massachusetts General Hospital Cystic Fibrosis Care Center. Dual-energy X-ray absorptiometry (DXA) was performed at the spine and radius at baseline and 2 years (in 39 subjects). Estimates of fat-free mass index (FFMI) and fat mass index (FMI) were determined using height, weight, and tetrapolar bioelectric impedance analysis. All subjects completed lung spirometry within 1 month of the study visit. Linear regression models evaluated predictors of baseline BMD Z-scores and change in PA spine BMD Z-score over 2 years. Two definitions of low BMD were studied based on Z-score (≤-1.0 and ≤-2.0).

RESULTS

Low BMD was present in 52% of subjects. Subjects with low BMD were more likely to be male (67% vs. 32%, P=0.009), were more likely to be currently using glucocorticoids (21% vs. 0%, P<0.001), had lower percent body fat (P=0.04), and were more likely to have had a previous fracture (60% vs. 46%, P=0.007). In multivariable models, greater FFMI and height, but not greater FMI, were associated with greater BMD. In multivariable models, low forced vital capacity (FVC) and greater FMI were associated with greater loss of BMD at the PA spine over two years.

CONCLUSIONS

Male sex, short stature, and low lean mass are associated with low BMD in CF. Greater adiposity and lower lung function are predictors of negative change in BMD Z-score over 2 years.

Lean mass and fat mass have differing associations with bone microarchitecture assessed by high resolution peripheral quantitative computed tomography in men and women from the Hertfordshire Cohort Study

Understanding the effects of muscle and fat on bone is increasingly important in the optimisation of bone health. We explored relationships between bone microarchitecture and body composition in older men and women from the Hertfordshire Cohort Study. 175 men and 167 women aged 72-81 years were studied. High resolution peripheral quantitative computed tomography (HRpQCT) images (voxel size 82 μm) were acquired from the non-dominant distal radius and tibia with a Scanco XtremeCT scanner. Standard morphological analysis was performed for assessment of macrostructure, densitometry, cortical porosity and trabecular microarchitecture. Body composition was assessed using dual energy X-ray absorptiometry (DXA) (Lunar Prodigy Advanced). Lean mass index (LMI) was calculated as lean mass divided by height squared and fat mass index (FMI) as fat mass divided by height squared. The mean (standard deviation) age in men and women was 76 (3) years. In univariate analyses, tibial cortical area (p<0.01), cortical thickness (p<0.05) and trabecular number (p<0.01) were positively associated with LMI and FMI in both men and women. After mutual adjustment, relationships between cortical area and thickness were only maintained with LMI [tibial cortical area, β (95% confidence interval (CI)): men 6.99 (3.97,10.01), women 3.59 (1.81,5.38)] whereas trabecular number and density were associated with FMI. Interactions by sex were found, including for the relationships of LMI with cortical area and FMI with trabecular area in both the radius and tibia (p<0.05). In conclusion, LMI and FMI appeared to show independent relationships with bone microarchitecture. Further studies are required to confirm the direction of causality and explore the mechanisms underlying these tissue-specific associations.

Bone Characteristics and Their Determinants in Adolescents and Young Adults with Early-Onset Severe Obesity

Childhood obesity is associated with compromised bone health. We studied bone characteristics and their determinants in obese young adults. The study included 68 subjects with early-onset severe obesity and 73 normal-weight controls. Data on physical activity (PA), diet and smoking were collected. Bone characteristics were measured using peripheral QCT. The obese and control subjects were similar in age (mean 19.6 ± 2.6 years) and height but BMIs differed (39.7 and 22.6 kg/m(2)). A clustering of unhealthy lifestyles was marked: Obese subjects reported less supervised PA in childhood, adolescence and currently (p < 0.03) and were more likely to smoke (p = 0.005), and had a lower healthy eating index (HEI) (p = 0.007) but similar alcohol consumption compared with controls. In obese women, all crude bone characteristics were higher than in controls; in men, the differences were smaller. Associations of lifestyle factors with bone characteristics were tested using partial correlations. Independently of BMI, supervised PA in adolescence and alcohol consumption were related positively to bone characteristics in both groups. HEI associated positively with bone characteristics only in controls, while smoking was a positive determinant of bone characteristics only in obese subjects. The multivariate model showed that the contribution of lifestyle factors to bone characteristics was minimal compared with BMI. Early-onset obesity is accompanied by poor dietary quality, sedentary lifestyle, and more frequent smoking, but the overall contribution of these lifestyle factors to bone strength is limited. Bone strength is more likely to be compromised in men and in unloaded bone sites in subjects with early-onset severe obesity. The impact of obesity-related endocrine changes on bone characteristics need to be evaluated in future studies.

Energy Excess, Glucose Utilization, and Skeletal Remodeling: New Insights

Skeletal complications have recently been recognized as another of the several comorbidities associated with diabetes. Clinical studies suggest that disordered glucose and lipid metabolism have a profound effect on bone. Diabetes-related changes in skeletal homeostasis result in a significant increased risk of fractures, although the pathophysiology may differ from postmenopausal osteoporosis. Efforts to understand the underlying mechanisms of diabetic bone disease have focused on the direct interaction of adipose tissue with skeletal remodeling and the potential influence of glucose utilization and energy uptake on these processes. One aspect that has emerged recently is the major role of the central nervous system in whole-body metabolism, bone turnover, adipose tissue remodeling, and beta cell secretion of insulin. Importantly, the skeleton contributes to the metabolic balance inherent in physiologic states. New animal models have provided the insights necessary to begin to dissect the effects of obesity and insulin resistance on the acquisition and maintenance of bone mass. In this Perspective, we focus on potential mechanisms that underlie the complex interactions between adipose tissue and skeletal turnover by focusing on the clinical evidence and on preclinical studies indicating that glucose intolerance may have a significant impact on the skeleton. In addition, we raise fundamental questions that need to be addressed in future studies to resolve the conundrum associated with glucose intolerance, obesity, and osteoporosis.

Positive Association Between Adipose Tissue and Bone Stiffness

Obesity is often considered to have a protective effect against osteoporosis. On the other hand, several recent studies suggest that adipose tissue may have detrimental effects on bone quality. We therefore aimed to investigate the associations between body mass index (BMI), waist circumference (WC), visceral adipose tissue (VAT) or abdominal subcutaneous adipose tissue (SAT), and bone stiffness. The study involved 2685 German adults aged 20-79 years, who participated in either the second follow-up of the population-based Study of Health in Pomerania (SHIP-2) or the baseline examination of the SHIP-Trend cohort. VAT and abdominal SAT were quantified by magnetic resonance imaging. Bone stiffness was assessed by quantitative ultrasound (QUS) at the heel (Achilles InSight, GE Healthcare). The individual risk for osteoporotic fractures was determined based on the QUS-derived stiffness index and classified in low, medium, and high risk. Linear regression models, adjusted for sex, age, physical activity, smoking status, risky alcohol consumption, diabetes, and height (in models with VAT or abdominal SAT as exposure), revealed positive associations between BMI, WC, VAT or abdominal SAT, and the QUS variables broadband-ultrasound attenuation or stiffness index. Moreover, BMI was positively associated with speed of sound. Our study shows that all anthropometric measures including BMI and, WC as well as abdominal fat volume are positively associated with bone stiffness in the general population. As potential predictors of bone stiffness, VAT and abdominal SAT are not superior to easily available measures like BMI or WC.

Bone density, microstructure and strength in obese and normal weight men and women in younger and older adulthood

Obesity is associated with greater areal BMD (aBMD) and is considered protective against hip and vertebral fracture. Despite this, there is a higher prevalence of lower leg and proximal humerus fracture in obesity. We aimed to determine if there are site-specific differences in BMD, bone structure, or bone strength between obese and normal-weight adults. We studied 100 individually-matched pairs of normal (body mass index [BMI] 18.5 to 24.9 kg/m2) and obese (BMI >30 kg/m2) men and women, aged 25 to 40 years or 55 to 75 years. We assessed aBMD at the whole body (WB), hip (TH), and lumbar spine (LS) with dual-energy X-ray absorptiometry (DXA), LS trabecular volumetric BMD (Tb.vBMD) by quantitative computed tomography (QCT), and vBMD and microarchitecture and strength at the distal radius and tibia with high-resolution peripheral QCT (HR-pQCT) and micro-finite element analysis. Serum type 1 procollagen N-terminal peptide (P1NP) and collagen type 1 C-telopeptide (CTX) were measured by automated electrochemiluminescent immunoassay (ECLIA). Obese adults had greater WB, LS, and TH aBMD than normal adults. The effect of obesity on LS and WB aBMD was greater in older than younger adults (p < 0.01). Obese adults had greater vBMD than normal adults at the tibia (p < 0.001 both ages) and radius (p < 0.001 older group), thicker cortices, higher cortical BMD and tissue mineral density, lower cortical porosity, higher trabecular BMD, and higher trabecular number than normal adults. There was no difference in bone size between obese and normal adults. Obese adults had greater estimated failure load at the radius (p < 0.05) and tibia (p < 0.01). Differences in HR-pQCT measurements between obese and normal adults were seen more consistently in the older than the younger group. Bone turnover markers were lower in obese than in normal adults. Greater BMD in obesity is not an artifact of DXA measurement. Obese adults have higher BMD, thicker and denser cortices, and higher trabecular number than normal adults. Greater differences between obese and normal adults in the older group suggest that obesity may protect against age-related bone loss and may increase peak bone mass.

Long-term effects of ovariectomy on the properties of bone in goats

Large animal models of osteoporosis are essential for osteoporosis research. However, the time required to establish an accurate osteoporosis model is unknown. Therefore, the aim of the present study was to establish a large animal model of osteoporosis in goats. In total, 14 Chinese goats were divided into an ovariectomized (OVX, n=7) or sham-operated (SHAM, n=7) group. Vertebral bodies were used to measure the bone mineral density (BMD) prior to the ovariectomy and at 24 months after the ovariectomy. In addition, the BMD of the femoral neck, femoral diaphysis and tibial diaphysis were measured 24 months postoperatively. Bone samples from the vertebral body, femoral head and femoral neck were scanned by micro-computed tomography (CT) to visualize the trabecular and cortical microstructure. Furthermore, the vertebral body, femoral head, femoral neck and tibial diaphysis were analyzed for mechanical strength. The BMD of vertebral body of the OVX group decreased significantly (P<0.01) at 24 months after the ovariectomy when compared with the baseline measurements. Micro-CT scans of the vertebral body revealed that the bone volume fraction, trabecular number, trabecular thickness and the degree of anisotropy decreased by 37.1, 36.7, 10.5 and 16.5%, respectively (P<0.01) in the OVX group when compared with the SHAM group. Additionally, the specific bone surface and trabecular spacing significantly increased by 37.7 and 62%, respectively in the OVX group (P<0.001). Cortical bone porosity in the vertebral body and femoral neck was greater in the OVX group when compared with the SHAM group (P<0.05). In addition, mechanical testing revealed a statistically significant difference between the vertebral bodies of the OVX group and the SHAM group. In conclusion, the present study demonstrated that an ovariectomy was able to induce significant osteoporosis and deterioration of mechanical properties in the bones of goats.

Adults with Prader-Willi syndrome have weaker bones: effect of treatment with GH and sex steroids

Obesity has been considered to have a protective effect against the risk of fractures in adults. However, a high frequency of fracture is described in obese adults with Prader-Willi syndrome. To evaluate bone geometry, density and strength in a group of adult obese patients with Prader-Willi syndrome (PWS) and to examine the modulating effect on bone of treatment with growth hormone (GH) and sex steroids. This was a cross-sectional study performed in 41 (17 males, 24 females) obese subjects with genetically confirmed PWS, aged 29.4 ± 8.6 years. Forty-six healthy subjects (22 males and 24 females) served as controls. Digitalized X-rays were evaluated at the level of the 2nd metacarpal bone to assess bone geometry, i.e. cross-sectional area (CSA), cortical area (CA), medullary area (MA), metacarpal index (MI) and bone strength evaluated as bending breaking resistance index (BBRI). DEXA was also used to evaluate body composition and bone mineral density (total body, lumbar spine and femoral neck). PWS subjects, after adjusting for height and bone size, had a reduced CSA, CA and BBRI, while bone density was not different. GH treatment had a positive effect and sex steroids a negative effect on bone size and strength. PWS subjects showed a reduced bone size at the metacarpus leading to a reduced strength, while bone density was appropriate for size. GH treatment improves bone geometry but not bone density. Bone strength was significantly reduced in PWS patients who did not receive GH and had been treated with sex steroids.