Appendicular Muscle Mass Index as the Most Important Determinant of Bone Mineral Content and Density in Small for Gestational Age Children

Preterm small for gestational age (SGA) children are at increased risk for low bone mineral content later in life; however, data on SGA children born at term are scarce. We included 44 SGA and 57 adequate for gestational age (AGA) children aged 6 to 11 years to compare bone mineral density (BMD) and bone mineral content (BMC) and to identify which anthropometric and biochemical values influence bone mineralization in these children. Fat mass, appendicular skeletal muscle mass index (ASMMI), BMC, and BMD were significantly lower in SGA children than in AGA (P ≤ .005). Appendicular muscle mass index correlated with BMC(TBLH,FN,L1-L4) and BMD(TBLH,FN,L1-L4) in both groups (r2 = 0.7, P < .05). In multivariate analysis, ASMMI was strongly associated with BMC and BMD in both groups. There were no differences in clinical biomarkers, calcium intake, and physical activity between the groups. Achieving adequate muscle mass contributes to adequate bone mineralization and a lower risk for low BMC and BMD in SGA children.

Shear Wave Elastography for Detecting Calf Muscle Stiffness: An Effective Tool for Assessing Sarcopenia

OBJECTIVES

To explore the feasibility of shear wave elastography for evaluating sarcopenia.

METHODS

The shear wave velocities (SWV) of the tibialis anterior, medial gastrocnemius, and soleus were measured in 130 subjects in the Second Affiliated Hospital of Fujian Medical University from January 2021 to June 2022. Consistency was evaluated in 20 cases using the intraclass correlation coefficient. According to the 2019 Asian Working Group for Sarcopenia（AWGS） diagnostic criteria, the patients were divided into a healthy and a sarcopenia group. The differences in SWV between the two groups were compared, and their correlation between calf muscles and muscle mass, grip strength, and pace were analyzed. The diagnostic cutoff value of calf muscle SWV for sarcopenia was obtained using receiver operating characteristic (ROC) curves, and the diagnostic efficacy of different ROC curves was compared.

RESULTS

The SWV inter-group and intra-group correlation coefficients of the three lower limbs muscles were all greater than 0.85. Moreover, the corresponding SWV in the sarcopenia group were significantly smaller than those in the healthy control group (P < .05). Further, SWV were positively correlated with the appendicular skeletal muscle mass index (ASMI), grip strength, and gait speed. Finally, the SWV of the anterior tibialis and medial gastrocnemius muscles were 3.02 and 2.26 m/s, respectively, and their diagnostic efficacy for sarcopenia did not differ significantly (Z = 0.190, P = .8497).

CONCLUSION

SWE can be used to detect the hardness of the anterior tibialis and medial gastrocnemius, calculate their muscle mass as an effective tool to evaluate sarcopenia.

The Prevalence Rate of Adult Sarcopenic Obesity and Correlation of Appendicular Skeletal Muscle Mass Index with Body Mass Index, Percent Body Fat, Waist-Hip Ratio, Basal Metabolic Rate, and Visceral Fat Area

Background: This study aimed to investigate the prevalence rate of adult sarcopenic obesity and discuss its predisposing factors. Methods: A total of 14,608 participants including 7521 men and 7087 women aged 18-93 years were enrolled in this study. The definition of sarcopenia was based on appendicular skeletal muscle mass index (ASMI) standards (≤7.0 kg/m² for men and ≤5.7 grams/m² for women). The definition of obesity followed percent body fat (PBF) ≥25% for men and ≥35% for women. Sarcopenic obesity was defined as the combination of sarcopenia and obesity diagnosis. Risk factors for the onset of sarcopenic obesity were analyzed by logistic regression analysis, followed by diagnostic value assessment. Results: There were 496 cases of sarcopenic obesity, including 308 male patients and 188 female patients. The overall prevalence rate was 3.4%, with 4.10% for men and 2.65% for women. Compared with nonsarcogenic obesity group, the subjects with sarcogenic obesity showed shorter height and circumference of limbs, arm muscle, neck, chest, waist and hip, lighter weight, lower body mass index (BMI), bone mineral content (BMC), skeletal muscle mass, basal metabolic rate (BMR), body cell mass, fitness score and ASMI, and higher body fat mass, PBF, waist-hip ratio (WHR), visceral fat area (VFA), extracellular fluid/total body fat, and extracellular water/total body water (ECW/TBW; P < 0.01). Based on logistic regression analysis, BMI, BMC, PBF, WHR, BMR, VFA, fitness score, lean balance trunk, lean balance left leg, ASMI, ECW/TBW and the circumference of left arm, left leg, arm muscle, chest waist and hip were considered as risk factors for sarcogenic obesity (P < 0.05). After receiver operating characteristic (ROC) curve analysis of basic condition, muscle mass, and limb condition, ASMI [area under the curve (AUC) = 0.75] showed relatively high diagnostic value for adult sarcopenic obesity; other indicators (AUC <0.75) showed moderate diagnostic value for adult sarcopenic obesity, except for fitness score. According to joint ROC analysis, combination of BMC, PBF, VFA, and ASMI (AUC = 0.78) showed high diagnostic value for adult sarcopenic obesity. ASMI was correlated with BMI (r = 0.246, P < 0.001), BMC (r = 0.798, P < 0.001), WHR (r = 0.197, P < 0.001), BMR (r = 0.932, P < 0.001), PBF (r = -0.761, P < 0.001), and VFA (r = -0.530, P < 0.001). In adult patients with sarcopenic obesity, a decrease in ASMI indicators may be accompanied by a decrease in BMI, BMC, WHR, and BMR as well as an increase in PBF and VFA. Conclusion: The prevalence rate of adult sarcopenic obesity was 3.40%. ASMI was closely correlated with BMI, BMC, PBF, WHR, BMR, and VFA, which may serve as early indicators in the diagnosis of adult sarcopenic obesity.

Correlation of muscle mass and bone mineral density in the NHANES US general population, 2017-2018

The appendicular skeletal muscle mass index (ASMI) is commonly used to evaluate human skeletal muscle mass. Muscle, an adjacent tissue of bone, is closely related to bone growth and development. The purpose of this study was to explore the association between the ASMI and lumbar bone mineral density (BMD) to identify potential risk factors for osteoporosis. We analyzed the data collected by the NHANES from 2017 to 2018, and finally included 948 participants aged 40 to 59 years. We evaluated the correlation between the ASMI and lumbar spine BMD using univariate and multiple linear regression models. The ASMI was calculated from height and appendicular skeletal muscle mass obtained by dual energy X-ray absorptiometry. Lumbar spine BMD was obtained by dual energy X-ray absorptiometry and used as an observation in our study. In all the models, ASMI was significantly associated with lumbar spine BMD (model 1: β = 0.013, P < .001; model 2: β = 0.013, P < .001). In the subgroup analysis stratified by sex, this positive correlation was present in both sexes (male: β = 0.023, P < .001, β = 0.022, < 0.001; female: β = 0.030, P < .001, β = 0.031, P < .001). This study showed that the ASMI was positively associated with lumbar BMD, and that this correlation is present in both men and women.

Prevalence of sarcopenia and mortality rate in older adults with hip fracture

BACKGROUND

Several international study groups adopted appendicular skeletal muscle mass (ASM) index adjusted by (1) height squared, (2) weight, and (3) body mass index (BMI) in the diagnosis of sarcopenia. However, different prevalence rates of sarcopenia by each index and clinical implications were not well known. The purpose of this study was to compare the differences in (1) the percentage of sarcopenia in hip fracture patients and (2) the relative mortality rate according to the sarcopenia criteria of three ASM indices.

METHODS

Between January 2009 and December 2020, 1003 older adult hip fracture patients at a tertiary institution were eligible and retrospectively reviewed for this study. Based on the ASM measured on dual-energy X-ray absorptiometry, three indices were calculated, and sarcopenia was diagnosed. The proportion of sarcopenia was evaluated according to each index. One, two, and five-year mortality rates were compared between each sarcopenia group and a normal musculature group, based on ASM criteria.

RESULTS

The proportion of sarcopenia patients differed according to three ASM indices. The proportion of sarcopenic patients by ASM/height² index was higher than those of the other two indices in both male and female hip fracture patients. In male patients, 61% were sarcopenic by ASM/height² index, 37% by ASM/weight index, and 44% by ASM/BMI index. In female patients, 26%, 11%, and 14% were sarcopenic, respectively. Among the three indices, only ASM/height² had significant correlations with all 1-, 2-, and 5-year mortality rates.

CONCLUSIONS AND IMPLICATIONS

The prevalence of sarcopenia in hip fracture patients differed substantially according to ASM indices. Sarcopenic hip fracture patients had a higher mortality rate than those with normal musculature. The 1-year, 2-year, and 5-year mortality rates were discriminated by ASM/height² criteria in both men and women. Future prospective studies in a larger cohort are warranted.

Using Virtual Reality-Based Rehabilitation in Sarcopenic Older Adults in Rural Health Care Facilities-A Quasi-Experimental Study

Because of a shortage of health care providers, providing rehabilitation in health care facilities is difficult. Virtual reality-based rehabilitation is effective in older populations. There are only a few studies among patients with sarcopenia. This is a quasi-experimental, single-group, pretest-posttest design evaluating the clinical effectiveness of virtual reality-based progressive resistance training among residents aged over 60 years with sarcopenia in rural care facilities. The authors used Oculus Rift with headsets to provide the virtual reality-based progressive resistance training. The authors administered the program twice per week, 30 min per session, for 12 weeks. The primary outcomes were dominant handgrip strength, walking speed, and appendicular skeletal muscle mass index. Data from 30 participants were analyzed. Significant improvements in handgrip strength and walking speed were observed. Although an increasing trend in appendicular skeletal muscle mass index was observed, it did not reach statistical significance. The authors concluded that the virtual reality-based progressive resistance training is partially effective in older sarcopenic adults in health care facilities.

Reference Values for Skeletal Muscle Mass - Current Concepts and Methodological Considerations

Assessment of a low skeletal muscle mass (SM) is important for diagnosis of ageing and disease-associated sarcopenia and is hindered by heterogeneous methods and terminologies that lead to differences in diagnostic criteria among studies and even among consensus definitions. The aim of this review was to analyze and summarize previously published cut-offs for SM applied in clinical and research settings and to facilitate comparison of results between studies. Multiple published reference values for discrepant parameters of SM were identified from 64 studies and the underlying methodological assumptions and limitations are compared including different concepts for normalization of SM for body size and fat mass (FM). Single computed tomography or magnetic resonance imaging images and appendicular lean soft tissue by dual X-ray absorptiometry (DXA) or bioelectrical impedance analysis (BIA) are taken as a valid substitute of total SM because they show a high correlation with results from whole body imaging in cross-sectional and longitudinal analyses. However, the random error of these methods limits the applicability of these substitutes in the assessment of individual cases and together with the systematic error limits the accurate detection of changes in SM. Adverse effects of obesity on muscle quality and function may lead to an underestimation of sarcopenia in obesity and may justify normalization of SM for FM. In conclusion, results for SM can only be compared with reference values using the same method, BIA- or DXA-device and an appropriate reference population. Limitations of proxies for total SM as well as normalization of SM for FM are important content-related issues that need to be considered in longitudinal studies, populations with obesity or older subjects.

Sarcopenia, obesity, and mortality in US adults with and without chronic kidney disease

Introduction

In predialysis chronic kidney disease (CKD), the association of muscle mass with mortality is poorly defined, and no study has examined outcomes related to the co-occurrence of low muscle mass and excess adiposity (sarcopenic obesity).

Methods

We examined abnormalities of muscle and fat mass in adult participants of the National Health and Nutrition Examination Survey 1999–2004. We determined whether associations of body composition with all-cause mortality differed between participants with CKD compared to those without.

Results

CKD modified the association of body composition with mortality (P = 0.01 for interaction). In participants without CKD, both sarcopenia and sarcopenic obesity were independently associated with increased mortality compared with normal body composition (hazard ratio [HR] = 1.44, 95% confidence interval [CI] = 1.07–1.93, and HR = 1.64, 95% CI = 1.26–2.13, respectively). These associations were not present among participants with CKD. Conversely, obese persons had the lowest adjusted risk of death, with an increased risk among those with sarcopenia (HR = 1.43, 95% CI = 1.05–1.95) but not sarcopenic-obesity (P = 0.003 for interaction by CKD status; HR = 1.21, 95% CI = 0.89–1.65), compared with obesity.

Discussion

Sarcopenia associates with increased mortality regardless of estimated glomerular filtration rate, but excess adiposity modifies this association among persons with CKD. Future studies of prognosis and weight loss and exercise interventions in CKD patients should consider muscle mass and adiposity together rather than in isolation.