Whole-body Skeletal Muscle Mass Research Articles

Evaluation of Muscle Mass and Malnutrition in Patients with Colorectal Cancer Using the Global Leadership Initiative on Malnutrition Criteria and Comparing Bioelectrical Impedance Analysis and Computed Tomography Measurements.

The aim of this investigation was to evaluate the discrepancies between bioelectrical impedance analysis (BIA) and computed tomography (CT) in assessing skeletal muscle mass and identifying low muscle mass in patients with colorectal cancer. This study recruited 137 patients with colorectal cancer from February 2028 to December 2023. CT scans were analyzed at the Lumbar 3 vertebral level to determine the area of skeletal muscle, which was then utilized to estimate whole-body skeletal muscle mass. [BIA] was also employed to measure skeletal muscle. Both skeletal muscle mass values [kg] were divided by height2 [m2] to calculate the skeletal muscle index [SMI, kg/m2], denoted as SMI-CT and SMI-BIA, respectively. The median age was 69.8 + 9.5 years, with the sex ratio being 88/49 [male/female]. Whereas more than one-third of the patients were classified as malnourished based on the Global Leadership Initiative on Malnutrition GLIM-CT criteria using L3-SMI [n = 36.5%], fewer patients were classified as malnourished based on GLIM-BIA using SMI-BIA [n = 19.0%]. According to the CT analysis [low SMI-L3], 52 [38.0%] patients were diagnosed as having poor muscle mass, whereas only 18 [13.1%] patients were identified as having low muscle mass using BIA [low SMIBIA]. The measured SMI showed a positive association with SMI-CT in all patients [r = 0.63, p < 0.001]. Using Bland-Altman evaluation, a significant mean bias of 0.45 + 1.41 kg/m2 [95% CI 0.21-0.70; p < 0.001] between SMI-BIA and SMI-CT was reported. Receiver operating characteristic (ROC) curves were generated to detect poor muscle mass using SMI-BIA with CT as the gold standard. The area under the curve (AUC) for SMI-BIA in identifying poor muscle mass was 0.714 (95% CI: 0.624-0.824), with a good cut-off value of 8.1 kg/m2, yielding a sensitivity of 68.3% and a specificity of 66.9%. BIA generally overestimates skeletal muscle mass in colorectal cancer patients when contrasted to CT. As a result, BIA may underestimate the prevalence of poor muscle mass and malnutrition according to the GLIM criteria in this patient population.

Association between Osteoporosis and Skeletal Muscle Mass in Men.

Cross-sectional study. This cross-sectional study aimed to investigate the risk factors for osteoporosis in men by assessing bone mineral density (BMD), skeletal muscle mass, body fat mass, grip strength, and advanced glycation end products (AGEs). Fewer studies have reported the correlation between BMD and skeletal muscle mass in women. Moreover, a few studies have examined the relationship between osteoporosis and skeletal muscle mass. This study included 99 men (mean age, 74.9 years; range, 28-93 years) who visited Qiball Clinic for BMD and body composition examinations. The osteoporosis group consisted of 24 patients (mean age, 72.5 years; range, 44-92 years), and the control group consisted of 75 individuals (mean age, 74.9 years; range, 28-93 years). Whole-body skeletal muscle mass was measured using a bioelectrical impedance analyzer. BMD was measured by dual X-ray absorptiometry. Skin autofluorescence (SAF), a marker of dermal AGE accumulation, was measured using a spectroscope. Osteoporosis was defined as a bone density T score of -2.5 or less. Physical findings, skeletal muscle mass, BMD, grip strength, and SAF were compared between the osteoporosis and control groups. The osteoporosis group had significantly lower trunk muscle mass (23.1 kg vs. 24.9 kg), lower leg muscle mass (14.4 kg vs. 13.0 kg), and skeletal mass index (7.1 kg/m2 vs. 6.7 kg/m2) than the control group (all p<0.05). Lower limb muscle mass was identified as a risk factor for osteoporosis in men (odds ratio, 0.64; p=0.03). Conservative treatment of osteoporosis in men will require an effective approach that facilitates the maintenance or strengthening of skeletal muscle mass, including exercise therapy with a focus on lower extremities and nutritional supplementation.

Comparison of bioelectrical impedance analysis and computed tomography for the assessment of muscle mass in patients with gastric cancer

BackgroundLow muscle mass was significantly correlated with poor clinical outcomes in cancer patients. This study aimed to compare the differences between bioelectrical impedance analysis (BIA) and computed tomography (CT) in measuring skeletal muscle mass and detecting low muscle mass in patients with gastric cancer (GC). MethodThis cross-sectional study included a total of 302 consecutive patients diagnosed with GC at our institution from October 2021 to March 2023. CT images were analyzed at the L3 level to obtain the cross-sectional area of skeletal muscle, which was subsequently used for calculating whole-body skeletal muscle mass via the Shen equation and skeletal muscle tissue density. BIA was utilized to measure skeletal muscle mass using the manufacturer's proprietary algorithms. Skeletal muscle mass (kg) was divided by height squared (m2) to obtain skeletal muscle index (SMI, kg/m2). Pearson's correlation coefficient was performed to assess the correlation between SMI measured by BIA and CT. The agreement between the two methods was assessed using Bland-Altman analyses. The clinically acceptable agreement was defined as the 95% limits of agreement (LOA) for the percentage bias falling within ± 10%. The area under the receiver operating characteristic curve (AUC) was used to evaluate the performance of BIA in identifying low muscle mass. ResultsA total of 59 patients (19.5%) were identified as having low muscle mass based on CT analysis, whereas only 19 patients (6.3%) met the criteria for low muscle mass according to BIA analysis. BIA-measured SMI showed a strong positive correlation with CT-measured SMI in all patients (r = 0.715, P < 0.001). With Bland-Altman analysis, there was a significant mean bias of 1.18 ± 0.96 kg/m2 (95% CI 1.07–1.29, P < 0.001) between SMI measured by BIA and CT. The 95% LOA for the percentage bias ranged from -7.98 to 33.92%, which exceeded the clinically acceptable range of ± 10%. A significant difference was observed in the mean bias of SMI measured by BIA and CT between patients with and without GLIM malnutrition (1.42 ± 0.91 kg/m2 versus 0.98 ± 0.96 kg/m2, P < 0.001). The cut-off values for BIA-measured SMI in identifying low muscle mass using CT as the reference were 10.11 kg/m2 for males and 8.71 kg/m2 for females (male: AUC = 0.840, 95% CI: 0.772–0.908; female: AUC = 0.721, 95% CI: 0.598–0.843). ConclusionsDespite a significant correlation, the values of skeletal muscle mass obtained BIA and CT cannot be used interchangeably. The BIA method may overestimate skeletal muscle mass in GC patients compared to CT, especially among those with GLIM malnutrition, leading to an underestimation of low muscle mass prevalence.

PERCENT TIME SPENT IN AN IMPAIRED GLUCOSE STATE AND ADVERSE MUSCLE OUTCOMES: THE SWAN STUDY

Abstract Sarcopenia is common among older adults, but associations of sarcopenia and diabetes are mixed. Beyond sarcopenia, relationships between glucose levels and muscle quality and power are understudied. We examined the association of time spent in an impaired glucose state and muscle outcomes. Muscle quality and power were assessed in 2015-2016 in 1,614 women (aged 66 + 2.7 years) without diabetes at baseline. Muscle quality was the average grip strength (measured in three trials using a Jamar dynamometer) per kilogram whole-body skeletal muscle mass (measured using bioelectrical-impedance analysis). Muscle power (Watts/kilogram body weight) was assessed using a 3-cycle timed stair climb: [(body weight (N)*stair height (m))/average ascent time (sec)]/body weight (kg). Fasting blood was collected at 11 visits; glucose ≥100mg/dL was considered impaired, with percent time spent in an impaired glucose state (%IGS) calculated as:(number visits with impaired glucose)/(number visits with glucose)*100 and categorized as ≤24%(n=1,203), 25-49%(n=184), 50-74%(n=136), ≥75%(n=91). Cross-sectional multivariable linear regression models were constructed for muscle outcomes with the independent predictor %IGS, adjusting for age, menopausal status, race/ethnicity, hormone use, and height. Compared to the lowest %IGS, all other groups had significantly lower mean muscle quality (β range: -0.091, -0.110 and -0.135, respectively) with the largest difference vs. highest %IGS (β= -0.135, 95%CI:-0.192,-0.077). Similar results were observed for muscle power (β range: -0.022, -0.024 and -0.020, respectively), though the highest %IGS was not significantly different. Results suggest that a longer time in an impaired glucose state from middle to older age may be associated with lower muscle function in older women.

Effects of effective antithyroid therapy on adiposity and skeletal muscle in patients with hyperthyroidism across gender and age groups.

The study aimed to evaluate the effects of effective antithyroid therapy on adiposity and skeletal muscle in patients with hyperthyroidism across gender and age groups. A total of 57 adult hyperthyroid patients (21 males and 36 females) who underwent effective antithyroid medication from January 2018 to January 2021 at Liuzhou People's Hospital and the First Affiliated Hospital of Guangxi Medical University were recruited and followed up for one year to observe the long-term efficacy of the antithyroid therapy. The eligible patients were divided by age and gender groups into male group A (males of <40 years old, n=12), female group A (females of <40 years old, n=19), male group B (males of 40-59 years old, n=8), female group B (female of 40-59 years old, n=13), and group C (patients of ≥60 years old, including one male and four females). A cohort of 57 healthy individuals was also recruited as controls. A Dual Energy X-ray (DXA) was performed to measure changes in fat and lean tissue mass and grip strength of the dominant hand before and after treatment and the body fat percentage (BFP). The whole-body skeletal muscle mass index (ASMI) was calculated to evaluate the long-term effects of antithyroid therapy. The eligible patients of all ages reported significantly increased total fat mass, body fat percentage, and body mass index (p<0.05). The total lean tissue mass was markedly increased in male and female group A (p<0.05), showed no significant changes in male and female group B (p>0.05), and exhibited a marked decline in group C (p<0.05). Significantly elevated ASMI after treatment was observed in male and female group A (p<0.05), while no significant changes were detected in ASMI after treatment in groups B and C (p>0.05). All patients in groups A and B exhibited enhanced grip strength, while the enhancement of grip strength in patients of group C was poor (p>0.05). Effective anti-hyperthyroidism therapy improves fat mass and body fat percentage in patients of all ages. However, gender and age differences exist in the effectiveness of improvements in total muscle mass and ASMI. Suboptimal muscle mass recovery was reported in patients over 40 years after effective anti-hyperthyroid therapy.

Skeletal muscle mass can be estimated by creatine (methyl-d3) dilution and is correlated with fat-free mass in active young males.

Assessing whole-body skeletal muscle mass (SMM) and fat-free mass (FFM) is essential for the adequate nutritional management and training evaluation of athletes and trained individuals. This study aimed to determine the relationship between SMM assessed using the creatine (methyl-d3) dilution (D3-creatine) method and SMM estimated by whole-body magnetic resonance imaging (MRI) in healthy young men undergoing exercise training. Additionally, we examined the association between FFM measured using the four-component (4C) method (FFM4C) and the total body protein value estimated using 4C (TBpro4C). We analyzed the data of 29 males (mean age, 19.9 ± 1.8 years) who exercised regularly. SMM measurements were obtained using the D3-creatine method (SMMD3-creatine) and MRI (SMMMRI). The SMMD3-creatine adjusted to 4.3 g/SMM kg was significantly higher than SMMMRI (p < 0.01). The fit of the creatine pool size compared with SMMMRI was 5.0 g/SMMMRI kg. SMMMRI was significantly correlated with both SMMD3-creatine adjusted to 4.3 g/kg and 5.1 g/kg. TBpro4C was significantly lower than SMMMRI (p < 0.01). Contrastingly, FFM4C was significantly higher than SMMMRI (p < 0.01). SMMD3-creatine adjusted to 4.3 g/SMM kg-a previously reported value-may differ for athletes and active young males. We believe that a value of 5.0-5.1 g/SMM kg better estimates the total muscle mass in this population. Traditional FFM estimation highly correlates with SMMMRI in well-trained young males, and the relationships appear strong enough for total body protein or SMM to be estimated through the FFM value.

Resistance Training Muscle Adaptations Using D3-creatine Dilution In Older Adults: A Pilot Study

High intensity resistance training (RT) is well known to increase muscle mass in older adults. However, the degree to which is dependent on the measurement method. D3-creatine (D3Cr) dilution is a promising new method that provides a direct and accurate measurement of creatine pool size and whole-body skeletal muscle mass. There are a limited number of studies that compare intervention-based adaptations between D3Cr derived skeletal mass versus lean mass by dual energy x-ray absorptiometry (DXA) Purpose: To evaluate and compare D3Cr derived skeletal mass and DXA lean mass changes following whole body progressive RT in moderate to low functioning older adults. Methods: Twenty-four older adults who tested as moderate to low-functioning on a standardized performance battery were randomized to a whole-body RT or health education program. RT was performed 3 days per week for 14 weeks. It included upper and lower body exercises performed at ~70% of maximal strength in progressive manner. Health education workshops were conducted weekly as an attention “control”. D3Cr dilution and whole body DXA scans were performed prior to randomization and shortly after completion of the programs. Results: D3Cr derived whole body skeletal mass increased more in participants randomized to the RT group compared to the health education group (3.5 ± 2.0 vs. 1.2 ± 1.7 kg, p = 0.03). Mean differences between groups was lower with DXA appendicular lean (RT: 0.81 ± 0.67 vs Education: -0.23 ± 0.70 kg, p = 0.008) and DXA total lean body mass (RT: 1.1 ± 1.4 vs Education: -0.19 ± 0.70 kg, p = 0.06). Pearson correlation coefficients showed weak relationships between changes in D3Cr muscle and DEXA appendicular (0.19, p = 0.48) and total lean mass measures (0.41, p = 0.13). Conclusions: This pilot study demonstrates that D3Cr dilution method is sufficiently sensitive to detect whole body changes in skeletal muscle mass of older adults. The unexpected discordance between D3Cr dilution and traditional DXA based measures of lean mass requires further study.

Effects of cigarette smoking on the association between respiratory muscle strength and skeletal muscle mass in middle-aged and older adults: the Wakayama Study.

This study aimed to examine whether cumulative smoking exposure affects the association between peak expiratory flow rate (PEFR) and skeletal muscle mass in middle-aged and older adults. The study participants comprised 832 community-dwelling individuals aged 50-89years (mean age: 69years) without chronic obstructive pulmonary disease. Bioelectrical impedance analysis was performed to estimate the skeletal muscle mass of each participant. PEFR was assessed using an electronic spirometer. Cumulative smoking exposure was expressed in pack years, that is a product of the average number of packs of cigarettes smoked per day and smoking duration in years. The whole-body skeletal muscle mass progressively reduced with decreasing PEFR levels in both males and females. In the multiple regression analysis, PEFR was found to be significantly associated with skeletal muscle mass, independent of the potential confounding factors. When participants were stratified based on the cumulative smoking exposure, the association between low PEFR and reduced skeletal muscle mass persisted in individuals with non-smoking and light-to-moderate smoking exposure (< 30 pack-years). However, this association was not clearly observed in individuals with heavy smoking exposure (≥ 30 pack-years). The findings of this study support the notion that PEFR declines with a reduction in systemic skeletal muscle mass due to aging. However, chronic cigarette smoking induces respiratory dysfunction exceeding the expected values by age, and thus a low PEFR level may not be used as a marker of reduced muscle mass in older adults exposed to heavy smoking.

β-hydroxy-β-methylbutyrate-enriched nutritional supplements for obese adults during weight loss: study protocol of a randomised, double-blind, placebo-controlled clinical trial

IntroductionObesity is a public health challenge worldwide. To maintain a healthy weight, dieting and lifestyle changes are the first-line interventions; however, these interventions are of poor compliance and may cause...

A 2-year longitudinal study of skeletal muscle mass in women over 40years of age with degenerative lumbar scoliosis.

We investigated changes in skeletal muscle mass and bone mineral density in degenerative lumbar scoliosis (DLS) patients during a 2-year follow-up following diagnosis. This study included 418 Japanese women, identifying 50 patients for the DLS group (mean age 76.4years) and 368 patients for the control group (mean age 73.4years). Whole-body skeletal muscle mass was measured using a Bioelectrical Impedance Analyzer. Bone mineral density (BMD) was measured using DXA. Skin autofluorescence (SAF), a marker of advanced glycation end products in the skin, was measured using a spectroscope. Spinal alignment, skeletal muscle mass, BMD, grip strength, and SAF were examined and the amount of change 1 and 2years from the initial examination for each item was compared between groups. Height, body fat mass, grip strength, upper limb muscle mass, and trunk muscle mass in the DLS group were significantly lower, and lumbar spine BMD was significantly greater compared to controls at the first visit (p < 0.05). There was no significant difference in spinal alignment in the DLS group after 2years compared with baseline. Trunk muscle mass also decreased significantly more in the DLS group (-2.7%) than in the control group (-1.1%) over the 2-year follow-up (p < 0.05). In this study, trunk muscle mass in the DLS group decreased about 2.4 times more in 2years compared with the control group (p < 0.05). It may be possible to clarify the mechanism of kyphoscoliosis progression in the future with large-scale longitudinal studies.

Diagnosing sarcopenia and myosteatosis based on chest computed tomography images in healthy Chinese\xa0adults

BackgroundMeasuring muscle mass and muscle quality based on chest Computed Tomography (CT) images would facilitate sarcopenia and myosteatosis research. We aimed (1) to measure muscle mass and myosteatosis based on chest CT images at the 12th thoracic vertebra level and compare the relevant indicators with whole-body skeletal muscle mass (BSM) and whole-body fat mass (BFM) measured by bioelectrical impedance analysis; and (2) to determine the cut-off points of these indicators for diagnosing sarcopenia or myosteatosis in healthy Chinese adults.MethodsChest CT images were analyzed using a segmentation software. Skeletal muscle area (SMA), skeletal muscle radiodensity (SMD), and intermuscular adiposity tissue (IMAT) were measured. Skeletal muscle indices (SMIs) and IMAT/SMA ratio were calculated.ResultsWe included 569 participants. SMA, SMA/height2, and SMA/BMI were strongly and positively correlated with BSM (r = 0.90, 0.72, and 0.69, respectively, all p < 0.001); whereas SMA/weight was moderately and positively correlated with BSM (r = 0.38, p < 0.001). IMAT and IMAT/SMA were strongly and positively correlated with BFM (r = 0.67 and 0.58, respectively, both p < 0.001). SMD was moderately and negatively correlated with BFM (r = − 0.40, p < 0.001). We suggest SMA/height2 (< 25.75 cm2/m2 in men and < 20.16 cm2/m2 in women) for diagnosing sarcopenia and SMD (< 37.42 HU in men and < 33.17 HU in women) or IMAT (> 8.72 cm2 in men and > 4.58 cm2 in women) for diagnosing myosteatosis.ConclusionsMuscle mass indicators (SMA and SMIs) and muscle quality indicators (SMD, IMAT, and IMAT/SMA) measured by chest CT images are valuable for diagnosing sarcopenia and myosteatosis, respectively.

Interrelationships among whole-body skeletal muscle mass, masseter muscle mass, oral function, and dentition status in older Japanese adults

BackgroundGeneralized loss of skeletal muscle mass (SMM) may modulate or otherwise affect the loss of masseter muscle mass and be responsible for low masseter muscle performance and strength (i.e., low oral function). Moreover, dentition status can affect oral function independent of the muscle state. This cross-sectional study aimed to simultaneously investigate the relationships among whole-body SMM, masseter muscle mass, oral function (masseter muscle performance and strength), and dentition status in 1349 Japanese adults (mean age = 73.6 years).MethodsWe determined the estimated masseter muscle mass (e-MMM) based on morphological measurements of the masseter muscle. Masseter muscle performance was assessed via masticatory performance evaluation scores using gum, and strength was assessed as the maximal occlusal force. Dentition status was assessed as the number of functional teeth. SMM was measured by bioelectrical impedance analysis. Structural equation modeling stratified by sex was employed to investigate associations among SMM, e-MMM, gum score, occlusal force, and number of functional teeth.ResultsThe direct path from SMM to e-MMM was statistically significant, as was the direct path from e-MMM to oral function (gum score and maximum occlusal force) for both sexes. We additionally confirmed that SMM indirectly affected gum score and maximum occlusal force via e-MMM (men; standardized coefficient [95% CI] = 3.64 [1.31 to 5.96] for maximum occlusal force and 0.01 [0.01 to 0.02] for gum score, women; 2.01 [0.38 to 3.81] for maximum occlusal force and 0.01 [0.002 to 0.01] for gum score). The number of functional teeth had direct effects on e-MMM, gum score, and maximum occlusal force.ConclusionsLow SMM was significantly indirectly associated with poor oral function through a low masseter muscle mass, and dentition status was independently associated with oral function.

Ultrasonography Shows Age-related Changes and Related Factors in the Tongue and Suprahyoid Muscles

ObjectivesTo investigate age and other factors related to the deterioration of the muscles used for swallowing, including the tongue and suprahyoid muscles. DesignCross-sectional study. Setting and ParticipantsThis study included 146 participants: 47 younger adults (23 men and 24 women; age range 23-44 years) recruited from a dental hospital and 99 community-dwelling older adults (37 men and 62 women, age range 65-86 years). MethodsAge (<65 years or ≥65 years), body mass index (BMI), skeletal muscle mass index (SMI), and tooth loss (Eichner classification) were measured. The cross-sectional areas (CSAs) of the tongue, geniohyoid muscle, and anterior belly of the digastric muscle were measured using an ultrasonic diagnostic apparatus. The correlation between each muscle's CSA and strength was examined. Multiple regression analyses were performed separately for each sex using each muscle CSA as the dependent variable and age, BMI, SMI, and the Eichner classification as explanatory variables. ResultsOlder men had a significant positive correlation between tongue pressure and CSA (r = 0.35, P = .031). Jaw opening force was positively correlated with geniohyoid muscle CSA (r = 0.41, P = .001) in older women. In the multiple regression analysis, age, BMI, and SMI were significantly associated with tongue CSA in men. Age was significantly and inversely associated with suprahyoid muscle CSA in both men and women. No explanatory variables were significantly associated with geniohyoid muscle CSA except age. Conclusions and ImplicationsThe tongue increased in volume, and the suprahyoid muscles underwent atrophy with age. The study results suggest that interventions to prevent dysphagia associated with aging should be tailored toward specific muscles. Direct muscle training is required for the suprahyoid muscles, whereas the maintenance of tongue muscle mass and function, as well as training for the tongue, requires attention to ensure optimal nutritional status and whole-body skeletal muscle mass.

The Genetic Effect on Muscular Changes in an Older Population: A Follow-Up Study after One-Year Cessation of Structured Training.

Older adults lose muscle mass and strength at different speeds after the cessation of physical exercise, which might be genotype related. This study aimed to explore the genetic association with changes in muscle mass and strength one year after the cessation of structured training in an older population. Participants (n = 113, aged between 61 and 81 years) who performed one-year of combined fitness (n = 44) or whole-body vibration (n = 69) training were assessed one year after the cessation of the training. Whole-body skeletal muscle mass and knee strength were measured. Data-driven genetic predisposition scores (GPSs) were calculated and analysed in a general linear model with sex, age, body mass index and post-training values of skeletal muscle mass or muscle strength as covariates. Forty-six single nucleotide polymorphisms (SNPs) from an initial 170 muscle-related SNPs were identified as being significantly linked to muscular changes after cessation. Data-driven GPSs and over time muscular changes were significantly related (p < 0.01). Participants with higher GPSs had less muscular declines during the cessation period while data-driven GPSs accounted for 26–37% of the phenotypic variances. Our findings indicate that the loss of training benefits in older adults is partially genotype related.

THU0610-HPR PREDICTION EQUATION FOR MUSCLE MASS OVERESTIMATES MUSCLE MASS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Background:Rheumatoid Arthritis (RA) is a chronic, progressive, inflammatory autoimmune disease characterized by systemic manifestations. Often is observed in RA patients changes in body composition, such as reduced muscle mass (sarcopenia) with stable or increased fat mass (FM) [1]. Total-body skeletal muscle mass (SMM), specifically appendicular skeletal muscle, is a key diagnostic feature for the assessment of geriatric syndromes associated with skeletal muscle wasting, such as sarcopenia [2]. Estimation of SMM can be accomplished by a variety of methods, but the majority that considered the gold standard for this purpose are high cost. Due high cost, this methods are unfeasible in population studies and increases the difficulty of use in different clinical contexts. Predictive equations have been developed for estimation of whole-body skeletal muscle mass on the basis of anthropometric data, which can be collected in a more affordable manner, in an attempt to make SMM calculation easier and enable its use in epidemiological research and in clinical settings [3]. However, these equations were not developed for RA populations.Objectives:To compare the anthropometric equation that estimate SMM with body composition measurements derived from DXA in RA patients.Methods:Ninety patients diagnosed with RA according to ACR/EULAR criteria were recruited. Body composition was assessed by total body dual-energy x-ray absorptiometry (DXA) for measurement of appendicular lean mass index (ALMI, kg/m2). The prediction equation for muscle mass proposed by Lee et al (variables included: body weight, height, age, sex and race) was used to generate estimates of SMM, stratified by BMI. Frequency analysis, independent student’s t test and intraclass correlation coefficients (ICC) were performed. Statistical significance was considered as p&lt;0.05Results:Of the 90 patients analyzed, most were women (86.7%; 78/91), with mean age of 56.5±7.3 and median disease duration time of 8.5 (3-18) years. The mean of BMI was 27.39±5.14. Thirty (33.3%) RA patients had normal weight, forty patients (44.4%) were overweight and twenty patients (22.2%) were obese. In normal weight patients, just like overweight and obese patients, the estimates of SMM obtained by Lee equation were higher than those obtained by DXA measurements(Obese: Lee 10.66±1.19 vs DXA 7.10±0.73; Overweight: Lee 8.63±0.99 vs DXA 6.57±0.82; Normal weight: Lee 7.14±0.85vs DXA 6.03±0.71; p&lt;0.05). The Lee equation estimates showed ICC of 0.78 (0.66 - 0.85) with DXA measurements. When stratified by BMI, Lee equation showed ICC of 0.87 (0.72 - 0.94) for normal weight, 0.83 (0.68 - 0.91) for overweight and 0.77 (0.42 - 0.90) for obese with DXA.Conclusion:The muscle mass index by Lee equation overestimates the muscle mass in overweight or obese RA patients compared to DXA. Thus, sarcopenic RA patients may be wrongly classified as normal by the equation. This is probably related to the obese cachexia that these patients often present. More studies are necessary to analysis to better prediction equations for muscle mass in RA patients.

Ultrasonography to detect age-related changes in swallowing muscles

Key summary pointsAimTo measure age-related changes in swallowing muscles by ultrasonography as a non-invasive method.FindingsBy ultrasonography, we found that old people had a smaller geniohyoid muscle area and greater geniohyoid muscle brightness than young people. Our analyses indicated that age and whole-body skeletal muscle mass were associated with mass and quality of the geniohyoid muscle.MessageUltrasonography effectively identified the association between atrophy of the swallowing muscles and aging and loss of whole-body skeletal muscle mass.

The correlation analysis between sagittal alignment and cross-sectional area of paraspinal muscle in patients with lumbar spinal stenosis and degenerative spondylolisthesis

BackgroundThe relationship between spinal alignment and skeletal muscle mass (SMM) has attracted attention in recent years. Sagittal alignment is known to deteriorate with age, but it is not known whether this is related to paraspinal muscles. Therefore, the purpose of this study is to elucidate the role of the multifidus (MF) and psoas major (PS) muscles in maintaining global spinal alignment in patients with lumbar spinal stenosis (LSS) and/or degenerative spondylolisthesis (DS), and to analyze whether each muscles’ cross-sectional area (CSA) correlates with whole-body SMM using bioimpedance analysis (BIA).MethodsWe retrospectively evaluated 140 patients who were hospitalized for surgery to treat LSS and/or DS. Spinal alignment, CSA of spinal muscles, and body composition parameters were measured from full-length standing whole-spine radiography, MRI, and BIA before surgery. The following standard measurements were obtained from radiographs: sagittal balance (C7-SVA), cervical lordosis (CL; C2–C7), lumbar lordosis (LL; L1–S1), thoracic kyphosis (TK; T5–T12), pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS).ResultsThe average PS CSA (AveCSA) was highest at L4-L5, whereas MF AveCSA was highest at L5-S1. Paraspinal muscle CSAs were greater in males than in females. There was no statistically significant difference between the left and right CSA for either MF or PS. Correlation coefficient showed strong correlations between the PS AveCSA (L4-L5) and whole body SMM (r = 0.739). Correlation coefficient analysis also showed weak correlation between SMM and PT (r = − 0.184). Furthermore, PS AveCSA (L4-L5) correlated with the PT (r = − 0.183) and age (r = − 0.156), while PT correlated with the whole body SMM (r = − 0.184) but not with age.ConclusionsWhole body SMM showed correlation with PS AvCSA (L4-L5) and with PT among the spinal parameters, which was the same result in MF AvCSA (L4-L5). These findings suggest that the posterior inclination of the pelvis may be correlated with paraspinal muscle area rather than age.

Automated segmentation of 2D low-dose CT images of the psoas-major muscle using deep convolutional neural networks.

The psoas-major muscle has been reported as a predictive factor of sarcopenia. The cross-sectional area (CSA) of the psoas-major muscle in axial images has been indicated to correlate well with the whole-body skeletal muscle mass. In this study, we evaluated the segmentation accuracy of low-dose X-ray computed tomography (CT) images of the psoas-major muscle using the U-Net convolutional neural network, which is a deep-learning technique. Deep learning has been recently known to outperform conventional image-segmentation techniques. We used fivefold cross validation to validate the segmentation performance (n = 100) of the psoas-major muscle. For the intersection over union and CSA ratio, segmentation accuracies of 86.0 and 103.1%, respectively, were achieved. These results suggest that the U-Net network is competitive compared with the previous methods. Therefore, the proposed technique is useful for segmenting the psoas-major muscle even in low-dose CT images.

Genetic predisposition score predicts the increases of knee strength and muscle mass after one-year exercise in healthy elderly.

This study aims to identify a genetic predisposition score from a set of candidate gene variants that predicts the response to a one-year exercise intervention. 200 participants (aged 60-83 years) were randomly assigned to a fitness (FIT), whole-body vibration (WBV) and control group. Participants in the exercise (FIT and WBV) groups performed a one-year intervention program. Whole-body skeletal muscle mass (SMM) and isometric knee extension strength (PTIM60) were measured before and after the intervention. A set of 170 muscle-related single nucleotide polymorphisms (SNPs) were genotyped. Stepwise regression analysis was applied to select significantly contributing SNPs for baseline and relative change parameters. A data-driven genetic predisposition score (GPS) was calculated by adding up predisposing alleles for each of the phenotypes. GPS was calculated based on 4 to 8 SNPs which were significantly related to the corresponding phenotypes. These SNPs belong to genes that are involved in myoblast differentiation, muscle and bone growth, myofiber contraction, cytokines and DNA methylation. GPS was related to baseline PTIM60 and relative changes of SMM and PTIM60 in the exercise groups, explaining the variance of the corresponding parameter by 3.2%, 14% and 27%, respectively. Adding one increasing allele in the GPS increased baseline PTIM60 by 4.73 Nm, and exercise-induced relative changes of SMM and PTIM60 by 1.78% and 3.86% respectively. The identified genetic predisposition scores were positively related to baseline knee extension strength and muscle adaptations to exercise in healthy elderly. These findings provide supportive genetic explanations for high and low responders in exercise-induced muscle adaptations.

The relationship between masseter muscle thickness and appendicular skeletal muscle mass in Japanese community-dwelling elders: A cross-sectional study

Purpose of the studySarcopenia has been identified as a health hazard in elderly people. Although the association between sarcopenia and a decrease in masticatory function has been reported, the mechanism underlying this association has not been widely reported. Therefore, in order to elucidate the relationship between sarcopenia and masticatory function, we examined whether the masseter muscle thickness (MMT), which is a factor influencing masticatory function, in community-dwelling elders is associated with the appendicular skeletal muscle index (SMI), a diagnostic criterion for sarcopenia. Materials and methodsMMT was measured in 774 community-dwelling elders aged 65 years or older at resting state via ultrasonography, and SMI was measured with the bioelectrical impedance method. The relationships were investigated by calculating Pearson's correlation coefficients. Multiple regression analyses adjusted for age and sex, SMI, and oral-related items were performed to determine the association between these factors. ResultsThere was a significant correlation between the MMT and the SMI. The multiple regression analysis indicated that SMI was significantly associated with a decrease in MMT. ConclusionsThe reduction in whole-body skeletal muscle mass in sarcopenia may be involved in the reduction in MMT. Prevention of sarcopenia may be an important factor for maintaining masticatory function in the elderly.