Bone mineral density and trabecular bone score in Chinese subjects with sarcopenia

Association between sarcopenia and osteoporosis: the cross-sectional study from NHANES 1999-2020 and a bi-directions Mendelian randomization study

Background

Osteoporosis (OP) and sarcopenia are prevalent musculoskeletal conditions among the elderly. Nevertheless, the causal relationship between sarcopenia and OP remains a subject of controversy and uncertainty. In this study, we employed cross-sectional analysis and Mendelian randomization (MR) to investigate the intricate relationship between sarcopenia and OP.

Methods

The cross-sectional study utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning 1999-2020, which involved in 116,876 participants. It assessed the correlation between sarcopenia, osteoporosis (OP), and bone mineral density (BMD) using Chi-square tests, T-tests, and a multiple logistic regression model. Additionally, we conducted Mendelian randomization (MR) analysis to investigate the causal effects of sarcopenia-related characteristics (ALM) on OP. We employed IVW, sensitivity analysis, heterogeneity testing, and other methods for MR. The ALM data was sourced from the UK Biobank (n=450,243), while the aggregated data on OP was obtained from GWAS statistics (n=53,236).

Results

In this cross-sectional analysis, we observed that in the multivariate logistic regression model, without adjusting for any variables, OP emerged as a risk factor for sarcopenia [OR 95% CI = 1.90 (1.13-3.18), P = 0.02]. Following adjustments for gender, age, BMI, and biochemical variables, OP retained its status as a risk factor for sarcopenia [OR 95% CI = 3.54 (1.91-6.54), P < 0.001]. Moreover, after accounting for all variables, OP emerged as an independent risk factor for sarcopenia [OR 95% CI = 4.57 (1.47-14.22), P = 0.01].In the MR analysis, we uncovered that femoral neck BMD (FN BMD), lumbar spine BMD (LS BMD), and forearm bone mineral density (FA BMD) exerted a direct causal influence on ALM [FA BMD: OR 95% CI = 1.028 (1.008, 1.049), p = 0.006; FN BMD: OR (95% CI) = 1.131 (1.092, 1.170), p = 3.18E-12; LS BMD: OR (95% CI) = 1.080 (1.062, 1.098), p = 2.86E-19].

Conclusion

Our study has revealed a positive correlation between OP and the prevalence of sarcopenia. It suggests a potentially robust causal relationship between OP and sarcopenia. Notably, OP appears to be associated with a higher likelihood of losing ALM, and a significant loss of ALM may contribute to a decline in LS BMD.

The genetic causal effect of hand grip strength on osteoporosis and falling risk: a Mendelian randomization study

Background

Patients with osteoporosis (OP) are often associated with decreased hand grip strength and increased risk of falling. It remains unclear whether there is a genetic causal between hand grip strength and OP, falling risk.

Methods

The Mendelian randomization study was used to investigate the genetic causal effect of low hand grip strength on total body bone mineral density (BMD) at different ages, OP, and falling risk. Genes for low hand grip strength, total body BMD at different ages, OP, and falling risk were obtained from published genome-wide association studies. Inverse variance weighted, MR-Egger, and weighted median were applied to perform the MR analysis. The Cochran's Q test, MR-Egger intercept test, MR-PRESSO global test, and leave-one-out analysis were used to detect the pleiotropy or heterogeneity.

Results

The results showed strong evidence that low hand grip strength was positively associated with OP (OR: 1.006, 95% CI: 1.003-1.010; P= 0.0001) and falling risk (OR: 1.069, 95% CI: 1.013-1.129; P= 0.0160), and could not directly affect the different ages of total body BMD (P> 0.05). There was no heterogeneity or horizontal pleiotropy in the sensitivity analysis (all P> 0.05).

Conclusion

The study found a positive causal relationship between low hand grip strength and higher risk of OP and falling, which should be taken into account in the development of future prevention and screening strategies for OP and falling.

Identification of Osteosarcopenia by High-Resolution Peripheral Quantitative Computed Tomography

Osteosarcopenia is a prevalent geriatric disease with a significantly increased risk of adverse outcomes than osteoporosis or sarcopenia alone. Identification of older adults with osteosarcopenia using High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT) could allow better clinical decision making. This study aimed to explore the feasibility of HR-pQCT to differentiate osteoporosis, sarcopenia, and osteosarcopenia in older adults, with a primary outcome to derive a model to distinguish older adults with osteosarcopenia from those with low bone mineral density only, and to examine important HR-pQCT parameters associated with osteosarcopenia. This was a cross-sectional study involving 628 community-dwelling Chinese adults aged ≥ 40. Subjects were assessed by dual energy X-ray absorptiometry (DXA) for osteopenia/osteoporosis and sarcopenia using the Asian Working Group for Sarcopenia definition; then grouped into healthy, osteopenia/osteoporosis, sarcopenia, and osteosarcopenia groups. A series of regression analyses and other statistical tests were performed to derive the model. HR-pQCT showed the ability to discriminate older adults with osteosarcopenia from those with osteopenia/osteoporosis only. Cross-validation of our derived model correctly classified 77.0% of the cases with good diagnostic power and showed a sensitivity of 76.0% and specificity of 77.6% (Youden index = 0.54; AUC = 0.79, p < 0.001). Analysis showed trabecular volumetric bone density and cortical periosteal perimeter were important and sensitive parameters in discriminating osteosarcopenia from osteopenia/osteoporosis subjects. These findings demonstrated that HR-pQCT is a viable and effective screening method for differentiating osteosarcopenia from low bone mineral density alone without the need to carry out multiple assessments for osteosarcopenia, especially for case-finding purposes. This could facilitate the decision of a follow-up and the management of these frail older adults to ensure they receive timely therapeutic interventions to minimise the associated risks.

Correlation study between bone metabolic markers, bone mineral density, and sarcopenia

OBJECTIVE

To investigate the correlation between bone metabolism markers, bone mineral density (BMD), and sarcopenia.

METHODS

A total of 331 consecutive patients aged ≥ 60 years who were hospitalized between November 2020 and December 2021 were enrolled. Participants were divided into sarcopenia and non-sarcopenia groups according to the Asian Working Group on Sarcopenia criteria (AWGS, 2019). The clinical data, bone metabolism markers (β-CTX, N-MID, and TP1NP), and BMD were compared between the two groups.

RESULTS

Age, β-CTX, and N-MID of the sarcopenia group were higher than those of the non-sarcopenia group (P < 0.05), but the BMD T values were lower than those of the non-sarcopenia group (P < 0.05). Binary logistic regression analysis showed that increased femoral neck BMD (FNBMD) was a protective factor for sarcopenia, while increased β-CTX was a risk factor. Pearson/Spearman correlation analysis showed that the diagnostic indices of sarcopenia were positively correlated with FNBMD and negatively correlated with β-CTX and N-MID. Multiple linear regression analysis revealed that BMI and FNBMD significantly positively affected muscle strength and appendicular skeletal muscle mass (ASM). The FNBMD significantly positively affected physical performance, while β-CTX significantly negatively affected muscle strength, ASM, and physical performance.

CONCLUSION

Increased FNBMD may be a protective factor against sarcopenia, and increased β-CTX may be a risk factor. The FNBMD significantly positively affected the diagnostic indices of sarcopenia, while β-CTX significantly negatively affected them. BMD and bone metabolism marker levels may be considered in early screening for sarcopenia.

A potential correlation between adipokines, skeletal muscle function and bone mineral density in middle-aged and elderly individuals

BACKGROUND

Evidence exists of a strong association between inflammation and a decrease in skeletal muscle function and bone mineral density (BMD); however, the specific mechanisms of these associations remain unclear. Adipokines, as key regulators of the inflammatory response, may be implicated in these processes. The objective of this study was to explore the potential correlation between adipokines, skeletal muscle function and BMD in middle-aged and elderly individuals.

METHODS

A comparative cross-sectional study was carried out at the Huadong Hospital Affiliated with Fudan University (Shanghai, China). A total of 460 middle-aged and elderly individuals were recruited, and 125 were enrolled in the analysis. Their biochemical indices, body composition, skeletal muscle function and BMD were measured. Bioinformatic analysis was also employed to identify potential adipokine targets linked to skeletal muscle function and BMD. To validate these targets, plasma and peripheral blood mononuclear cells (PBMCs) were harvested from these individuals and subjected to western blotting (WB) and enzyme-linked immunosorbent assay (ELISA).

RESULTS

Individuals in this cross-sectional study were categorized into 2 groups according to their median skeletal muscle mass (SMM) (28.8 kg for males and 20.6 kg for females). Individuals with lower SMM exhibited poorer grip strength (P = 0.017), longer 5-Times-Sit-to-Stand Test (FTSST) duration (P = 0.029), lower total hip BMD (P = 0.043), lower femoral neck BMD (P = 0.011) and higher levels of inflammatory markers in comparison with individuals with higher SMM. Bioinformatics analysis identified LEP, ADIPOQ, RBP4, and DPP4 as potential adipokine targets associated with skeletal muscle function and BMD. In vitro experiments demonstrated that individuals with decreased skeletal muscle function and BMD expressed higher levels of these adipokines.

CONCLUSIONS

Skeletal muscle function is positively correlated with BMD and negatively correlated with levels of inflammatory markers among middle-aged and elderly individuals. Those with lower skeletal muscle function and BMD tend to have a higher expression of LEP, ADIPOQ, RBP4 and DPP4.

Ultrasonic Through-Transmission Measurements of Human Musculoskeletal and Fat Properties

The study described here was aimed at investigating the feasibility of using the ultrasonic through-transmission technique to estimate human musculoskeletal and fat properties. Five hundred eighty-two volunteers were assessed by dual-energy X-ray absorptiometry (DXA) and ultrasonic transmission techniques. Bone mineral density (BMD), muscle and fat mass were measured for both legs and the whole body. Hip BMD and spine BMD were also measured. Ultrasonic transmission measurements were performed on the heel, and the measured parameters were broadband ultrasound attenuation (BUA), speed of sound (SOS), ultrasonic stiffness index (SI), T-score and Z-score, which were significantly correlated with all measured BMDs. The optimal correlation was observed between SI and left-leg BMD (p < 0.001) before and after adjustment for age, sex and body mass index (BMI). The linear and partial correlation analyses revealed that BUA and SOS were closely associated with muscle and fat mass, respectively. Multiple regressions revealed that muscle and fat mass significantly contributed to the prediction of transmission parameters, explaining up to 17.83% (p < 0.001) variance independently of BMD. The results suggest that the ultrasonic through-transmission technique could help in the clinical diagnosis of skeletal and muscular system diseases.

Exploring the Temporal Correlation of Sarcopenia with Bone Mineral Density and the Effects of Osteoblast-Derived Exosomes on Myoblasts through an Oxidative Stress-Related Gene

Sarcopenia is an age-related accelerated loss of muscle strength and mass. Bone and muscle are closely related as they are physically adjacent, and bone can influence muscle. However, the temporal association between bone mineral density (BMD) and muscle mass in different regions of the body after adjustment for potential indicators and the mechanisms by which bone influences muscle in sarcopenia remain unclear. Therefore, this study aimed to explore the temporal association between muscle mass and BMD in different regions of the body and mechanisms by which bone regulates muscle in sarcopenia. Here, cross-lagged models were utilized to analyze the temporal association between BMD and muscle mass. We found that low-density lipoprotein (LDL-C) positively predicted appendicular lean mass. Mean whole-body BMD (WBTOT BMD), lumbar spine BMD (LS BMD), and pelvic BMD (PELV BMD) temporally and positively predicted appendicular lean mass, and appendicular lean mass temporally and positively predicted WBTOT BMD, LS BMD, and PELV BMD. Moreover, this study revealed that primary mice femur osteoblasts, but not primary mice skull osteoblasts, induced differentiation of C2C12 myoblasts through exosomes. Furthermore, the level of long noncoding RNA (lncRNA) taurine upregulated 1 (TUG1) was decreased, and the level of lncRNA differentiation antagonizing nonprotein coding RNA (DANCR) was increased in skull osteoblast-derived exosomes, the opposite of femur osteoblast-secreted exosomes. In addition, lncRNA TUG1 enhanced and lncRNA DANCR suppressed the differentiation of myoblasts through regulating the transcription of oxidative stress-related myogenin (Myog) gene by modifying the binding of myogenic factor 5 (Myf5) to the Myog gene promoter via affecting the nuclear translocation of Myf5. The results of the present study may provide novel diagnostic biomarkers and therapeutic targets for sarcopenia.

A Predictive Model for Abnormal Bone Density in Male Underground Coal Mine Workers

The dark and humid environment of underground coal mines had a detrimental effect on workers’ skeletal health. Optimal risk prediction models can protect the skeletal health of coal miners by identifying those at risk of abnormal bone density as early as possible. A total of 3695 male underground workers who attended occupational health physical examination in a coal mine in Hebei, China, from July to August 2018 were included in this study. The predictor variables were identified through single-factor analysis and literature review. Three prediction models, Logistic Regression, CNN and XG Boost, were developed to evaluate the prediction performance. The training set results showed that the sensitivity of Logistic Regression, XG Boost and CNN models was 74.687, 82.058, 70.620, the specificity was 80.986, 89.448, 91.866, the F1 scores was 0.618, 0.919, 0.740, the Brier scores was 0.153, 0.040, 0.156, and the Calibration-in-the-large was 0.104, 0.020, 0.076, respectively, XG Boost outperformed the other two models. Similar results were obtained for the test set and validation set. A two-by-two comparison of the area under the ROC curve (AUC) of the three models showed that the XG Boost model had the best prediction performance. The XG Boost model had a high application value and outperformed the CNN and Logistic regression models in prediction.

Body Composition as a Modulator of Bone Health Changes in Patients with Inflammatory Bowel Disease

Background: Bone impairment of multifactorial etiology is a common feature in inflammatory bowel disease (IBD). Body composition parameters, which might be selectively modified in these patients, are important determinants of bone strength. Our aim was to investigate the relationship between components of body composition and bone parameters in IBD patients. Methods: This is a cross-sectional, retrospective study including 80 IBD patients (43 women, 37 men). Lumbar spine (LS), femoral neck (FN) and whole body DXA scans were performed to analyze regional bone mineral density (BMD), as well as body composition, including appendicular skeletal muscle mass index (ASMI), total and visceral fat mass (VAT). Trabecular bone score (TBS) was assessed using iNsight Software. Results: Twenty (25%) IBD patients had inadequate LS-BMD z scores (<=−2DS). Lean mass (LM) was a significant determinant of LS-BMD, after adjusting for age, gender, BMI and fat mass (p < 0.01), while fat mass% remained associated with FN-BMD (p < 0.01). TBS correlated positively with BMI (r = 0.24, p < 0.05), LS-BMD (r = 0.56, p < 0.001), ASMI (r = 0.34, p < 0.001) and negatively with VAT/total fat% (r = −0.27, p < 0.05). Multivariate analysis showed that ASMI, LS-BMD (positively) and VAT/total fat% (negatively) were independently associated with TBS. Conclusions: In IBD patients, skeletal muscle mass and fat percentage and distribution are important factors associated with bone health.

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.

Factors associated with degraded trabecular bone score in heart transplant recipients

Trabecular bone score (TBS) is a textural index that provides indirect evaluation of trabecular microarchitecture. It improves fracture risk assessment in several high-risk populations. We aimed to evaluate the role of TBS assessment in heart transplant recipients (HTR). In a cross-sectional study with 87 HTR (69 males and 18 females), we assessed TBS and evaluated potential associations between TBS and factors related to increased fracture risk. We also evaluated the correlations between the presence of vertebral fractures (VF) and degraded TBS. We confirmed degraded TBS in the majority of HTR. 27.6% of HTR had partially degraded, 27.6% had degraded TBS. HTR with degraded TBS were older, had higher body mass index, lower bone mineral density (BMD), and T-score. As opposed to stable BMD over different time points, TBS significantly differed among different post-transplant time periods. TBS did not correlate with current methylprednisolone or past zoledronic acid treatment, presence of hypogonadism or diabetes. TBS did not have additional value over BMD in predicting the presence of VF. Most fractures occurred in patients with osteopenia and in patients with partly degraded TBS. Studies with longitudinal designs and larger sample sizes are warranted to further assess the potential role of TBS in HRT.

Integrating Muscle Health in Predicting the Risk of Asymptomatic Vertebral Fracture in Older Adults

Background: The utility of muscle health for predicting asymptomatic vertebral fracture (VF) is uncertain. We aimed to determine the effects of muscle health on bone quantity and quality in the older adults and to integrate these factors into a predictive model for VF. Methods: We prospectively recruited participants with a body mass index <37 kg/m². The total lean mass (TLM), appendicular skeletal muscle index, presence of sarcopenia, and bone mineral density were determined by dual-energy X-ray absorptiometry, and bone quality by the trabecular bone score (TBS). VF was diagnosed based on spine radiography. Results: A total of 414 females and 186 males were included; 257 participants had VF. Lower TLM was significantly associated with poorer bone quantity and quality in both males and females. A low TBS (OR: 11.302, p = 0.028) and sarcopenia (Odds ratio (OR): 2.820, p = 0.002) were significant predictors of VF in males, but not bone quantity. Moreover, integrating TBS and sarcopenia into the predictive model improved its performance. Conclusions: Although TLM was associated with bone quantity and quality in both sexes, sarcopenia and a low TBS were significant predictors of asymptomatic VF only in male participants.

Associations between Physical Function, Bone Density, Muscle Mass and Muscle Morphology in Older Men with Sarcopenia: A Pilot Study

Background and Objectives: It is thought that muscle and bone interact only on a biomechanical level, however, some research is now emerging that links bone and muscle on a cellular level. The aim of this study was to explore associations between physical function, muscle mass and bone density in community-dwelling elderly men with sarcopenia. A secondary goal was to analyze if muscle morphology was associated with bone density and physical functioning. Materials and Methods: Body composition was measured by dual-energy X-ray absorptiometry (DXA). Bone density was evaluated according to WHO criteria. Sarcopenia was diagnosed according to European Working Group on Sarcopenia in Older People (EWGSOP) criteria: low muscle mass and low muscle strength or low physical performance. Microbiopsy of musculus vastus lateralis was performed with a disposable muscle microbiopsy system. The perimeter and cross-sectional area of muscle fibers were calculated using image analysis software in whole slide images; type of fibers and their distribution were evaluated as well. Results: A total of 151 men, 60 years or older were included in this study. Mean age of the subjects was 72.9 ± 8.02 years. Sarcopenia was diagnosed in 45 (29.8%) men. Multiple significant correlations were found between bone mineral density, lean mass, appendicular lean mass, arm and leg lean mass, gait speed, balance test and handgrip strength in sarcopenic men. Lean mass was associated with femoral neck BMD (bone mineral density; r = 0.418, p = 0.006) and handgrip strength (r = 0.553, p < 0.001). In the sarcopenia group, 25 muscle biopsies were examined. In 9 sarcopenic men with T-scores equal or below -2.5, the muscle fiber area had a significant correlation with the balance test (r = 0.73, p = 0.025). Conclusions: In men with sarcopenia, low lean muscle mass was associated with low femoral neck BMD and low muscle strength. In sarcopenic men with osteoporosis, low muscle fiber area was associated with low scores in a balance test.

Impact of Bone Fracture on Muscle Strength and Physical Performance-Narrative Review

PURPOSE OF REVIEW

Low muscle strength and poor physical performance are associated with high risk of fracture. Many studies assessed clinical and functional outcomes of fractures. Fewer studies analyzed the impact of fractures on muscle strength and physical performance.

RECENT FINDINGS

Vertebral fractures (especially multiple and severe ones) are associated with back pain, back-related disability, lower grip strength, lower strength of lower limbs, lower gait speed, and poor balance. Patients with hip fracture have slower gait and lower quadriceps strength. Non-vertebral fractures were associated with lower strength of the muscles adjacent to the fracture site (e.g., grip strength in the case of distal radius fracture, knee extensors in the case of patellar fracture) and poor physical function dependent on the muscles adjacent to the fracture site (e.g., limited range of motion of the shoulder in the case of humerus fracture, gait disturbances in the case of the ankle fracture). Individuals with a fracture experience a substantial deterioration of muscle strength and physical performance which exceeds that related to aging and is focused on the period close to the fracture occurrence. After fracture, muscle strength increased and physical performance improved. The rate of normalization depended partly on the therapeutic approach and on the rehabilitation program. A subgroup of patients, mainly the elderly, never returns to the pre-fracture level of physical performance. The permanent decline of physical function after fracture may be related to the limitation of movements due to pain, low physical activity, poor health before the fracture, and reduced efficacy of retraining after immobilization.

Muscle-Bone Interactions in Chinese Men and Women Aged 18-35 Years

To characterize bone mineral density (BMD), bone strength, muscle and fat mass, and muscle strength and power in Chinese women (n = 25) and men (n = 28) classified as in the bone accrual phase (18-25 years) or in the peak bone mass phase (26-35 years). Calcium intakes, physical activity levels, and serum vitamin D were measured. Dual-energy X-ray absorptiometry (DXA) assessed body composition, lumbar spine, and hip areal BMD (aBMD) variables and peripheral quantitative computed tomography (pQCT) assessed cortical and trabecular volumetric BMD (vBMD) and bone strength. Muscle strength and power were assessed by grip strength, leg press, and vertical jump tests. Calcium, serum vitamin D, and physical activity levels were similar across age and sex groups. Significant sex differences (p < 0.05) were found for most body composition variables, hip aBMD, tibia variables, and muscle strength and power. Adjusting for height and weight eliminated most of the significant sex differences. Women showed stronger positive correlations between body composition and bone variables (r = 0.44 to 0.78) than men. Also, correlations between muscle strength/power were stronger in women vs. men (r = 0.43 to 0.82). Bone traits were better related to body composition and muscle function in Chinese women compared to Chinese men aged 18 to 35 years, and peak bone mass seems to be achieved by 25 years of age in both Chinese men and women since there were no differences between the two age groups.