Estimation Of Muscle Mass Research Articles

Prevalence of sarcopenia in a Scottish cohort with chronic kidney disease (CKD) receiving haemodialysis and its association with clinical parameters

The presence of chronic kidney disease (CKD) has been suggested to elicit early onset reductions in lean body mass leading to disease related sarcopenia and poor functional performance. We investigated the prevalence of sarcopenia in a Scottish cohort receiving long term (>6 months) haemodialysis and its association with age, dialysis vintage, comorbidity and inflammation. The diagnosis of sarcopenia was based on the European consensus definition and diagnosis. Handgrip as a marker of muscle strength was measured pre dialysis. Height and weight were measured post dialysis for the calculation of body mass index (BMI). Calf circumference (CC) and mid arm muscle circumference (MAMC) were measured post dialysis as anthropometric estimates of muscle mass. Dual frequency bioelectrical impedance analysis (DFBIA) was also measured post dialysis to derive skeletal muscle index (SMI). Functional performance was assessed using the 6-minute walk test and number of sit-to-stand transitions performed in 1 minute. Comorbidity scores were determined using the Charlson co-morbidity index scoring system, monthly high sensitivity C-reactive protein (hsCRP) results were used to determine the presence of inflammation and dialysis vintage was calculated from the first date renal replacement therapy was initiated. Sixty-four patients were recruited 39 male & 25 female with a mean age of 54 years 16 (SD) and BMI of 27·6 Kg/m 6·3 (SD), mean hsCRP was 11·6 mgL 5·1 (SD), mean dialysis vintage was 75·0 months 84·8 (SD). 43·8% were identified as sarcopenic, with 26·6% presenting with severe sarcopenia. Sarcopenic obesity was present in 20·3%. Those with sarcopenia performed fewer sit-to-stand transitions and walked less distance in 6 minutes than those without sarcopenia. Whilst a significant difference in SMI was observed between those with and without sarcopenia, no difference in calf circumference or mid arm muscle circumference was evident.

HIGHER APPENDICULAR AND TRUNK FAT MASS USING BIOELECTRICAL IMPEDANCE ANALYSIS ARE RELATED TO HIGHER RESTING BLOOD PRESSURE IN OLDER ADULTS

Background: Little is known about how fat mass and muscle mass in different parts of the body (e.g., appendages, trunk) using bioelectrical impedance analysis influences resting blood pressure in older adults. Objective: The purpose of the study was to clarify the association between resting blood pressure and muscle mass and fat mass in older adults using bioelectrical impedance analysis. Design: A cross-sectional study. Settings: A sample living independently in the community. Participants: The subjects were older adults between the ages of 65 and 85 years (n = 100). Measurements: Systolic, diastolic and mean arterial pressure was measured using an automatic hemodynamometer, and bioelectrical impedance analysis was used to estimate muscle mass and fat mass. Results: A positive correlation was observed between total fat mass, left and right arm fat mass, trunk fat mass, and left and right leg fat mass and resting systolic, diastolic and mean arterial pressure (p < 0.05), but this was not observed with any muscle mass (p > 0.05). In a multiple regression analysis adjusted for sex, systolic, diastolic and mean arterial pressure were independently predicted by total fat mass, left and right arm fat mass, trunk fat mass, and left and right leg fat mass (p < 0.05). Conclusions: These findings suggest that total, appendicular, and trunk fat mass, measured using bioelectrical impedance analysis, could aid in detecting the factors that increase blood pressure in clinical settings and even in daily life, thereby helping in controlling blood pressure.

Sarcopenia among hospitalized patients – A cross-sectional study

Data on the prevalence of sarcopenia among hospitalized older patients are scarce and there is no available information on the burden of sarcopenia among younger patients. The present study aims to increase the knowledge about the frequency of sarcopenia among hospitalized patients and to evaluate the influence of different diagnostic criteria in these estimates. A cross-sectional study was conducted in hospitalized adult patients. Sarcopenia was defined, according to the European Working Group on Sarcopenia in Older People (EWGSOP), as the presence of both low muscle mass, assessed by Bioelectrical Impedance Analysis (BIA), adjusted for height, and low muscle function (hand grip strength). Two other criteria were applied, also using hand grip strength for evaluating muscle function, one that also assessed muscle mass by BIA, but adjusted for weight, and another which estimated muscle mass based on mid-arm muscle circumference. Nutritional status was evaluated by Patient-Generated Subjective Global Assessment. The degree of agreement between the different diagnostic criteria was assessed using kappa. Multivariable logistic regression models were used in order to identify factors associated with sarcopenia. 608 hospitalized adult patients aged ≥18 years composed the study sample. According to EWGSOP's criteria, 25.3% patients were sarcopenic. However, depending on age and on the applied criteria, frequency of sarcopenia varied from 5% to 41.1% for men and from 4.9% to 38.3% for women. There was 95.7% (k = 0.89) agreement between criteria that estimated muscle mass by BIA. According to EWGSOP criteria approximately 20% of the non-undernourished patients were sarcopenic. Furthermore, 29.5% of overweight and 18.7% of obese patients were sarcopenic. Factors associated with sarcopenia were male gender, age ≥65 years, moderate or severe dependence, being undernourished and admitted to a medical ward. Sarcopenia is frequent among hospitalized patients and varies widely depending on the applied diagnostic criteria. Sarcopenia was identified in a considerable proportion of patients aged under ≥65 years and in non-undernourished, namely among overweight and obese.

Adductor pollicis muscle: A study about its use as a nutritional parameter in surgical patients

Body composition is important to identify malnutrition, and several anthropometric measurements are used to estimate muscle mass in the clinical practice. This study aimed to assess the adductor pollicis muscle thickness (APMT), its covariates and association with malnutrition in hospitalized surgical patients. APMT was measured in 361 surgical patients in both dominant (DAPMT) and non-dominant (NDAPMT) sides. APMT values below the 5th percentile of reference values provided by a healthy population were considered as malnourished. Nutritional status was assessed by Subjective Global Assessment (SGA). The difference in APMT values among nutritional status categories was evaluated, and the association between malnutrition by SGA and APMT was estimated using multivariate linear regression. Sensitivity, specificity and positive and negative predictive values were also calculated. Most patients were women (60.4%). APMT values were significantly different among SGA categories. Well-nourished patients had APMT values significantly higher compared to the ones with moderate or severe malnutrition by SGA, with no significant difference between APMT values in moderate or severe malnourished patients. Statistically significant associations between both DAPMT and NDAPMT below the 5th percentile and malnutrition and were found (RR = 3.99, CI 95% = 3.19-5.00; p < 0.001; and RR = 3.92; CI 95% = 3.10-4.96; p < 0.001; respectively). Gender, age, estimated weight and nutritional status were considered associated factors for APMT. APMT showed low sensitivity (DAPMT: 34.9%, NDAPMT: 37.7%) but high specificity (DAPMT: 98.7%, NDAPMT: 97.8%) to identify malnutrition. APMT was significantly associated with nutritional status in a sample of surgical patients. The APMT seems to be a simple and useful anthropometric tool to confirm the diagnosis of malnutrition.

Serum levels of C-terminal agrin fragment (CAF) are associated with sarcopenia in older hip fractured patients

BackgroundSerum concentrations of the C-terminal fragment of agrin (CAF), a component of the neuromuscular junction (NMJ), are elevated in older community-dwellers with sarcopenia. Whether CAF may be used as a marker for muscle wasting in the presence of NMJ mechanical damage is presently unknown. The present study was undertaken to verify if serum CAF levels were associated with sarcopenia in older hip fractured patients. MethodsAnalyses were conducted in older adults hospitalized for traumatic hip fracture. The presence of sarcopenia was established according to the European Working Group on Sarcopenia in Older People criteria, with bioelectrical impedance analysis used for muscle mass estimation. Serum levels of CAF were determined using a commercial ELISA kit. ResultsAmong 42 hip fractured patients (age 83.7±8.6years, 76.2% women), sarcopenia was diagnosed in 7 individuals (16.7%). Serum CAF levels were significantly higher in sarcopenic relative to non-sarcopenic patients (172.2±47.5pM vs. 93.1±44.0pM; p<0.001). The association remained significant in both genders after adjustment for several potential confounders. ConclusionElevated serum CAF concentrations are associated with sarcopenia in older adults with hip fracture. The determination of serum CAF levels could therefore serve to identify a subset of hip fractured patients at especially high risk for adverse health outcomes.

Urine Creatinine–Based Estimates of Fat-Free Mass in Community-Dwelling Older Persons: The Rancho Bernardo Study

To determine whether a previously developed and externally validated equation using common variables (demographics and weight) that are important determinants of muscle mass to estimate 24-hour urine creatinine excretion rate (eCER) is associated with muscle mass and whether spot urine creatinine (UCr) provides similar estimates of muscle mass. Observational cross-sectional cohort study. The Rancho Bernardo Study, San Diego, California. A total of 1,371 Caucasian, middle class, community-dwelling older adults. Morning spot UCr and fat-free mass (FFM) by dual-energy x-ray absorptiometry were measured. eCER was calculated: eCER (mg/day) = 879.89 + 12.51 × weight (kilogram) - 6.19 × age + 34.51 if black - 379.42 if female. Pearson correlation coefficients and linear regression were used to determine strengths of association of eCER and spot UCr with FFM. Mean age was 70 years, and 58% were women. eCER was strongly correlated with FFM (r = 0.95, P < .001), a correlation that was superior to that of spot UCr (r = 0.40, P < .001). An equation incorporating age, weight, sex, and race to estimate eCER is highly correlated with FFM in community-dwelling older persons and provides a more precise estimate than spot UCr. A simple screening tool for sarcopenia in older persons may allow interventions to maintain or improve muscle mass. Future studies should evaluate whether eCER predicts sarcopenia-related frailty and mortality in older persons.

O4.20: Intramuscular adipose tissue and the functional components of sarcopenia

Introduction: When defining sarcopenia, muscle mass/strength and functionality are used. Although these three components are linked, their exact relation is not clear. Not only muscle quantity, but also muscle quality needs to be investigated. This study examines the role of intramuscular adipose tissue (IMAT) in the sarcopenia work-up. Methods: All patients admitted to the Geriatrics Department (01/08/2012–31/01/2013) were screened for muscle mass/strength and functionality. Muscle mass was measured by CT imaging of both upper legs. Muscle strength was measured by handgrip strength. Functionality was measured by Short Physical Performance Battery (SPPB). Results: Of 301 included patients, 211 (69.6%) were female. Overall muscle mass was 527±15 grams (range 60–1325). Overall IMAT was 29.2±13.0% (range 3.2–86.2%). Men had more muscle mass (p < 0.001) and less IMAT (p < 0.001) than women. Overall mean handgrip strength was 13.1±8.8 kg (range 0–52kg). There was a negative correlation between handgrip strength and IMAT. Mean SPPB-score was 4±3, median was 3 (range 0–12). SPPB-scores were positively correlated with both handgrip strength (p < 0.001) and muscle mass (p < 0.001). There was a negative correlation between SPPB-scores and IMAT (p < 0.001). Conclusion: In hospitalized geriatric patients a high percentage and wide variability of IMAT was found. It is necessary to measure the IMAT, when estimating muscle mass in the workup of sarcopenia Techniques that do not take this into account will overestimate muscle mass. This might be a reason for the limited correlation between muscle mass and strength/function. IMAT, however, is significantly negatively correlated with muscle function and strength.

Shorter Telomeres in Peripheral Blood Mononuclear Cells from Older Persons with Sarcopenia: Results from an Exploratory Study

Background: Telomere shortening in peripheral blood mononuclear cells (PBMCs) has been associated with biological age and several chronic degenerative diseases. However, the relationship between telomere length and sarcopenia, a hallmark of the aging process, is unknown. The aim of the present study was therefore to determine whether PBMC telomeres obtained from sarcopenic older persons were shorter relative to non-sarcopenic peers. We further explored if PBMC telomere length was associated with frailty, a major clinical correlate of sarcopenia.Methods: Analyses were conducted in 142 persons aged ≥65 years referred to a geriatric outpatient clinic (University Hospital). The presence of sarcopenia was established according to the European Working Group on Sarcopenia in Older People criteria, with bioelectrical impedance analysis used for muscle mass estimation. The frailty status was determined by both the Fried’s criteria (physical frailty, PF) and a modified Rockwood’s frailty index (FI). Telomere length was measured in PBMCs by quantitative real-time polymerase chain reaction according to the telomere/single-copy gene ratio (T/S) method.Results: Among 142 outpatients (mean age 75.0 ± 6.5 years, 59.2% women), sarcopenia was diagnosed in 23 individuals (19.3%). The PF phenotype was detected in 74 participants (52.1%). The average FI score was 0.46 ± 0.17. PBMC telomeres were shorter in sarcopenic subjects (T/S = 0.21; 95% CI: 0.18–0.24) relative to non-sarcopenic individuals (T/S = 0.26; 95% CI: 0.24–0.28; p = 0.01), independent of age, gender, smoking habit, or comorbidity. No significant associations were determined between telomere length and either PF or the FI.Conclusion: PBMC telomere length, expressed as T/S values, is shorter in older outpatients with sarcopenia. The cross-sectional assessment of PBMC telomere length is not sufficient at capturing the complex, multidimensional syndrome of frailty.

Assessment and definition of lean body mass deficiency in the elderly.

Although the effect of age on body composition has been intensively discussed during the past 20 years, we do not have a uniform definition of sarcopenia. A suitable definition of low, lean body mass should be based on magnetic resonance imaging (MRI) estimates of muscle mass. Using recent MRI data of a population of 446 healthy free-living Caucasian volunteers (247 females, 199 males) age 18-78 years, a low skeletal muscle mass and sarcopenia were defined as a skeletal muscle mass >1 and >2 s.d. below the mean value obeserved in younger adults at age 18-39 years. The cutoffs for low muscle mass according to the skeletal muscle index (skeletal muscle mass/(height)(2)) or the appendicular skeletal muscle mass index (skeletal muscle mass of the limbs/(height)(2)) were 6.75 or 4.36 kg/m(2) for females and 8.67 or 5.54 kg/m(2) for males, respectively. On the basis of these cutoffs, prevalences of sarcopenia in the group of adults at >60 years are calculated to be 29% in females and 19.0% in males. Faced with different sarcopenic phenotypes (that is, sarcopenia related to frailty and osteopenia; sarcopenic obesity related to metabolic risks; cachexia related to wasting diseases), future definitions of sarcopenia should be extended to the relations between (i) muscle mass and adipose tissue and (ii) muscle mass and bone mass. Suitable cutoffs should be based on the associations between estimates of body compositions and metabolic risks (for axample, insulin resistance), inflammation and muscle function (that is, muscle strength).

Association between Sarcopenia and Metabolic Syndrome in Chronic Obstructive Pulmonary Disease: The Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2011

Aim: It is not clear whether the restrictive or obstructive pattern of spirometry is associated with metabolic syndrome. We investigated the associations between restrictive and obstructive spirometric patterns and metabolic risk factors using data from the Korea National Health and Nutrition Examination Survey (KNHANES). Additionally, we investigated whether sarcopenia is associated with metabolic syndrome in patients with chronic obstructive pulmonary disease (COPD). Methods: Using data from KNHANES between 2008 and 2011, we enrolled 8,145 subjects (normal lung function: 6,077, obstructive spirometric pattern: 1,039, restrictive pattern: 1,029) aged ≥40 years who underwent anthropometric measurement, laboratory tests, spirometry and estimation of appendicular muscle mass. Sarcopenia was defined as an appendicular skeletal muscle mass divided by body weight squared <2 SD below the sex-specific mean for the young reference group. Results: Sarcopenia was found in 32.8% of male and 12.2% of female patients with COPD. The odds ratio (OR) of metabolic syndrome for the restrictive spirometric pattern in male was 1.29 (95% confidence interval [CI], 1.02–1.65), and that for obstructive pattern in males was 0.99 (95% CI, 0.79–1.26) after adjustments for covariables (female restrictive pattern (ORs, 1,45; 95% CI, 1.09–1.91) and female obstructive pattern (ORs 0.73; 95% CI, 0.49–1.09). After adjustment for other confounding factors, the risk of metabolic syndrome was higher in sarcopenic male (OR, 1.88; 95% CI, 1.27–2.77) with COPD than in those without sarcopenia. Conclusions: The restrictive spirometric pattern is associated with metabolic syndrome, and sarcopenia may contribute to the risk of metabolic syndrome in male patients with COPD.

Total body skeletal muscle mass: estimation by creatine (methyl-d3) dilution in humans.

Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses [n = 35: 20 men (19-30 yr, 70-84 yr), 15 postmenopausal women (51-62 yr, 70-84 yr)] were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r = 0.868, P < 0.0001), with less bias compared with lean body mass assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total lean body mass assessment by DXA.

Creatinine Index as a Surrogate of Lean Body Mass Derived from Urea Kt/V, Pre-Dialysis Serum Levels and Anthropometric Characteristics of Haemodialysis Patients

Background and ObjectivesProtein-energy wasting is common in long-term haemodialysis (HD) patients with chronic kidney disease and is associated with increased morbidity and mortality. The creatinine index (CI) is a simple and useful nutritional parameter reflecting the dietary skeletal muscle protein intake and skeletal muscle mass of the patient. Because of the complexity of creatinine kinetic modeling (CKM) to derive CI, we developed a more simplified formula to estimate CI in HD patients.Design, Setting, Participants & MeasurementsA large database of 549 HD patients followed over more than 20 years including monthly CKM-derived CI values was used to develop a simple equation based on patient demographics, predialysis serum creatinine values and dialysis dose (spKt/V) using mixed regression models.ResultsThe equation to estimate CI was developed based on age, gender, pre-dialysis serum creatinine concentrations and spKt/V urea. The equation-derived CI correlated strongly with the measured CI using CKM (correlation coefficient = 0.79, p-value <0.001). The mean error of CI prediction using the equation was 13.47%. Preliminary examples of few typical HD patients have been used to illustrate the clinical relevance and potential usefulness of CI.ConclusionsThe elementary equation used to derive CI using demographic parameters, pre-dialysis serum creatinine concentrations and dialysis dose is a simple and accurate surrogate measure for muscle mass estimation. However, the predictive value of the simplified CI assessment method on mortality deserves further evaluation in large cohorts of HD patients.

Predicting muscle mass from anthropometry using magnetic resonance imaging as reference: a systematic review

Identification and management of sarcopenia are limited by lack of reliable simple approaches to assess muscle mass. The aim of this review is to identify and evaluate simple methods to quantify muscle mass/volume of adults. Using Cochrane Review methodology, Medline (1946-2012), Embase (1974-2012), Web of Science (1898-2012), PubMed, and the Cochrane Library (to 08/2012) were searched for publications that included prediction equations (from anthropometric measurements) to estimate muscle mass by magnetic resonance imaging (MRI) in adults. Of 257 papers identified from primary search terms, 12 studies met the inclusion criteria. Most studies (n = 10) assessed only regional/limb muscle mass/volume. Many studies (n = 9) assessed limb circumference adjusted for skinfold thickness, which limits their practical applications. Only two included validation in separate subject-samples, and two reported relationships between whole-body MRI-measured muscle mass and anthropometry beyond linear correlations. In conclusion, one simple prediction equation shows promise, but it has not been validated in a separate population with different investigators. Furthermore, it did not incorporate widely available trunk/limb girths, which have offered valuable prediction of body composition in other studies.

Availability and use of dual energy X‐ray absorptiometry (DXA) and bio‐impedance analysis (BIA) for the evaluation of sarcopenia by Belgian and Latin American geriatricians

Dear Editor, Sarcopenia is the age-associated progressive loss of skeletal muscle mass and function, with higher risk of adverse outcomes [1, 2]. The cause of sarcopenia is still unclear, but the determinants are likely to be a combination of genetic and environmental factors [2–4]. Computed tomography and magnetic resonance imaging are considered the gold standard to estimate muscle mass. However, their high cost and limited availability preclude their routine use in clinical settings [5, 6]. Dual energy X-ray absorptiometry (DXA) and bio-impedance analysis (BIA) are alternative methods for research and clinical use to measure skeletal muscle mass [7]. In the last years, BIA and DXA have been used frequently in the field of research, but it is not known to what extent the recommendations for screening and diagnosis are followed nor to what extent the suggested techniques are available in clinical practice [8]. Therefore, the aim of this study was to evaluate the availability and use of these techniques in clinical practice of Belgian and Latin American geriatricians. Geriatricians were asked four questions by a web-based survey system in order to determine availability and use of both techniques. The questions were: “Does your hospital have a BIA system?” and “Does your hospital have a DXA scanner for measuring muscle mass?” If one or both of the questions were affirmative, it was asked whether they had used the respective technique during the last month. As shown in Fig. 1 in the group of Latin Americans, 170 geriatricians were contacted of whom 94 (55.0 %) responded (Mexico, Brazil, and Costa Rica responded most frequent). In Belgium, 133 geriatricians were contacted and 50 (37.6 %) responded. The Latin American geriatricians had greater availability of both techniques (BIA and DXA) than their Belgian counterparts (22 vs 35 and 35 vs 30 %, respectively). In Latin American, BIA was more available than DXA (35 vs 30 %). In Belgium, BIA was less available than DXA (22 vs 34 %). The overall use of these techniques for measuring muscle mass was 10.0 % for DXA and 4.0 % for BIA among Belgian geriatricians. In Latin America, the reported use of both techniques was higher than in Belgium, specifically for DXA (12 vs 10 %; p < 0.0001). For BIA, the difference was less pronounced (17 vs 4 %; p = 0.18). Centers that had DXA were more likely to also have BIA available (p < 0.001); this was true in Belgium as well as in Latin America (see Table 1). Fig. 1 Flowchart of the study Table 1 Comparison of availability and use of DXA/BIA between Belgium and Latin American countries Availability of the techniques recommended for the measurement of muscle mass is not very broad. In Belgium, excluding university hospitals, general hospitals use only 28 % for DXA and even less for BIA (10 %). The overall availability in Latin America is comparable with the situation in Belgium with a reversed preponderance of BIA over DXA availability. Regardless from the availability, the actual use of these studies was lower for DXA with only about 10 % in both regions. In Belgium, the use of BIA in the screening for sarcopenia was negligible. Nevertheless, interpretation should be careful. Sarcopenia remains still a relatively new concept, and it can be expected that in the years to come, the knowledge of this condition will improve along with the detection of this condition. In addition, search for inexpensive and readily available detection tools should continue in fields such as anthropometry (calf circumference). Easy and available clinical indicators could provide valuable information on muscle-related disability and physical function and have a preponderant role in screening, leaving BIA and DXA for intervention decisions and follow-up.

2P1-18 生体電気インピーダンス法による部位別推定筋量を用いて野球選手のパフォーマンスを評価する方法の開発

2P1-18 生体電気インピーダンス法による部位別推定筋量を用いて野球選手のパフォーマンスを評価する方法の開発

Muscle strength and its relationship with skeletal muscle mass indices as determined by segmental bio-impedance analysis

Despite increasing interest in bio-impedance analysis (BIA) for estimation of segmental skeletal muscle mass (SMM), published results have not been entirely convincing. Furthermore, a better understanding of the relationship between muscle strength and SMM will be useful in interpreting outcomes of physical/training interventions particularly in groups with diverse body sizes (e.g. men vs women). This study aimed to measure SMM in the upper body (upper extremity and torso), to determine its correlation with muscle strength and to examine the effects of gender on muscle strength-muscle mass relationship. Segmental (upper extremity and torso) SMM and muscle strength in five distinct shoulder planes (forward flexion, abduction in scapular plane, abduction in coronal plane, internal and external rotation) were measured in 45 healthy participants (22 males, 23 females) with mean age 30.3 years. Statistical analysis included independent t tests, Pearson correlation, and multiple regression analysis. Men and women differed significantly in body mass (BMI: 25.9 ± 4.3 vs 23 ± 3.6) and SMM (p < 0.01). A strong relationship correlation was found between the five shoulder strength measurements and upper extremity SMM (r = 0.66-0.80, p < 0.01), which was not affected by gender. There was a significant gender difference (p < 0.01) in absolute shoulder strength, but not after normalisation to the SMM. BIA-estimated SMM of upper extremity and torso was highly correlated with upper extremity (shoulder) strength independent of gender. SMM may, therefore, be useful for the normalisation of muscle strength allowing size-independent comparisons of muscle strength in individuals with diverse physical characteristics.

Estimation of thigh muscle cross-sectional area by single- and multifrequency segmental bioelectrical impedance analysis in the elderly

Bioelectrical impedance analysis (BIA) has been used to estimate skeletal muscle mass, but its application in the elderly is not optimal. The accuracy of BIA may be influenced by the expansion of extracellular water (ECW) relative to muscle mass with aging. Multifrequency BIA (MFBIA) can evaluate the distribution between ECW and intracellular water (ICW), and thus may be superior to single-frequency BIA (SFBIA) to estimate muscle mass in the elderly. A total of 58 elderly participants aged 65-85 years were recruited. Muscle cross-sectional area (CSA) was obtained from computed tomography scans at the mid-thigh. Segmental SFBIA and MFBIA were measured for the upper legs. An index of the ratio of ECW and ICW was calculated using MFBIA. The correlation between muscle CSA and SFBIA was moderate (r = 0.68), but strong between muscle CSA and MFBIA (r = 0.85). ECW/ICW index was significantly and positively correlated with age (P < 0.001). SFBIA tends to significantly overestimate muscle CSA in subjects who had relative expansion of ECW in the thigh segment (P < 0.001). This trend was not observed for MFBIA (P = 0.42). Relative expansion of ECW was observed in older participants. The relative expansion of ECW affects the validity of traditional SFBIA, which is lowered when estimating muscle CSA in the elderly. By contrast, MFBIA was not affected by water distribution in thigh segments, thus rendering the validity of MFBIA for estimating thigh muscle CSA higher than SFBIA in the elderly.

Protein markers predict body composition during growth hormone treatment in short prepubertal children

A high-throughput pharmaco-proteomic approach has previously been successfully used to identify lipoprotein biomarkers related to changes in longitudinal growth and bone mass in response to growth hormone (GH) treatment. The aim of this study was to identify protein markers involved in the diverse anabolic and lipolytic remodelling of body composition during GH treatment. The study population consisted of 128 prepubertal children receiving GH treatment. Thirty-nine were short as a result of GH deficiency, and 89 had idiopathic short stature (ISS). Serum protein expression profiles at study start and after 1year of GH treatment were analysed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS). Body composition was analysed by dual-energy X-ray absorptiometry (DXA), reliably estimating muscle mass from appendicular (arms and legs) lean soft tissue mass (LST). DXA was also used to estimate appendicular bone mineral content (BMC) and fat mass for the total body. Specific protein expression patterns associated with GH response in different body compartments were identified. Among identified proteins, different isoforms of nutrition markers such as apolipoproteins (Apo) were recognized: Apo C-I, Apo A-II, serum amyloid A4 (SAA4) and transthyretin (TTR). In addition, unidentified peaks were associated with GH effects on specific body compartments. Our results suggest that unique protein markers are associated with remodelling of different body compartments during GH treatment, which in the future might be useful to optimize GH treatment not only with regard to longitudinal growth.

Estimation of Total Body Skeletal Muscle Mass in Chinese Adults: Prediction Model by Dual-Energy X-Ray Absorptiometry

BackgroundThere are few reports on total body skeletal muscle mass (SM) in Chinese. The objective of this study is to establish a prediction model of SM for Chinese adults.MethodologyAppendicular lean soft tissue (ALST) was measured by dual energy X-ray absorptiometry (DXA) and SM by magnetic resonance image (MRI) in 66 Chinese adults (52 men and 14 women). Images of MRI were segmented into compartments including intermuscular adipose tissue (IMAT) and IMAT-free SM. Regression was used to fit the prediction model . Age and gender were adjusted in the fitted model. The piece-wise linear function was performed to further explore the effect of age on SM. ‘Leave-One-Out Cross Validation’ was utilized to evaluate the prediction performance. The significance of observed differences between predicted and actual SM was tested by t test and the level of agreement was assessed by the method of Bland and Altman.ResultsMen had greater ALST and IMAT-free SM than women. ALST was the primary predictor and highly correlated with IMAT-free SM (R2 = 0.94, SEE = 1.11 kg, P<0.001). Age was an additional predictor (SM prediction model with age adjusted R 2 = 0.95, SEE = 1.05 kg, P<0.001). There was a piece-wise linear relationship between age and IMAT-free SM: IMAT-free SM = 1.21×ALST−0.98, (Age <45 years) and IMAT-free SM = 1.21×ALST−0.98−0.04× (Age−45), (Age ≥45years). The prediction performance of this age-adjusted model was good due to ‘Leave-One-Out Cross Validation’. No significant difference between measured and predicted IMAT-free SM was detected.ConclusionPrevious SM prediction model developed in multi-ethnic groups underestimated SM by 2.3% and 3.4% for Chinese men and women. A new prediction model by DXA has been established to predict SM in Chinese adults.

Usefulness and limitations of single-slice computed tomography analysis at the third lumbar region in the assessment of sarcopenia

In the previous issue of Critical Care, Moisey and colleagues [1] report that sarcopenia has potential to serve as a predictor for mortality, discharge disposition, and ICU utilization. Sarcopenia may be mitigated by adequate nutrition supply and early rehabilitation, and so identification of patients with ICU-acquired weakness, who could benefit from rehabilitation, is of fundamental importance [2]. Sarcopenia diagnosis is based on estimation of muscle mass. Whole-body imaging methods like computed tomography (CT) and magnetic resonance imaging (MRI) can precisely measure muscle mass, but limitations of these modalities led to new tools for daily practice. The European Working Group on Sarcopenia in Older People (EWGSOP) recommends the use of dual-energy x-ray absorptiometry (DXA) as an alternative [3]. Nowadays, single-slice CT image analysis, which was used in the study by Moisey and colleagues, is becoming a popular alternative. Validation of this technique was previously assessed by comparing the single-slice CT analysis at the third lumbar (L3) region with DXA, which is not the gold standard [4]. Measurement errors related to DXA might affect these validation results. Although Shen and colleagues [5] compared single-slice CT analysis and whole-body MRI, they reported results for the fourth-fifth lumbar region, not for the L3 region. Moreover, this study was conducted among healthy subjects and this limited the generalization of results for the ICU setting. The EWGSOP recommends the measurement of muscle power, function, and mass for a sarcopenia diagnosis [3]. As muscle function and power data of patients were not reported in the present article, we do not know whether all participants were accurately classified as sarcopenic.