Appendicular Lean Soft Tissue Research Articles

Changes in Bone Mineral Density in Patients With Non-dialysis-Dependent Chronic Kidney Disease Are Associated With Body Composition

Chronic kidney disease (CKD) and low bone mineral density (BMD) are highly prevalent and can co-exist. Parameters of mineral metabolism are associated with BMD in CKD, but other contributing factors may contribute. The aim of this study was to assess changes in BMD and its determinants in patients with non-dialysis-dependent CKD (NDD-CKD). Body composition and biochemical profiles were assessed in a retrospective hospital-based cohort study of patients with NDD-CKD. BMD, lean soft tissue (LST), appendicular LST (ALST), and percentage fat mass were assessed by dual-energy X-ray absorptiometry (DXA). ALST index (ALSTI, ALST/height2) and load-capacity index (LCI, fat mass/LST) were calculated. Low BMD was defined as t-score ≤-1.0. Mean time between assessments was 2.8±1.3 years, 46 patients were included. A reduction in renal function was observed. Changes in body composition included reductions in ALST (p=0.031), ALSTI (p=0.021) and a trend for BMD (p=0.053); and an increase in percentage fat mass (p=0.044) and LCI (p=0.032). Females had a reduction in BMD (p=0.034), ALST (p=0.026), and ALSTI (p=0.037). Patients with low BMD at baseline had lower LST (p=0.013), ALST (p=0.023), and percentage fat mass (p=0.037) than those with normal BMD. Additionally, reductions in LST (p=0.041), ALST (p=0.006), and ALSTI (p=0.008) were observed in patients who had low BMD at baseline, while no significant changes in body composition were observed in those with normal BMD at baseline. The following body composition parameters at baseline were determinants of BMD status at follow-up: LST (OR:0.899, 95%CI:0.829-0.976, p=0.010), ALST (OR:0.825, 95%CI:0.704-0.967, p=0.017), and ALSTI (OR:0.586, 95%CI:0.354-0.968, p=0.037), independent of fat mass, and LCI. Detrimental body composition changes were observed without changes in body weight; these were more significant in females. Moreover, this is the first longitudinal study showing a protective effect of LST against BMD loss in patients with NDD-CKD.

Nutrient Intake and Its Association with Appendicular Total Lean Mass and Muscle Function and Strength in Older Adults: A Population-Based Study.

Treatment options for sarcopenia are currently limited, and primarily rely on two main therapeutic approaches: resistance-based physical activity and dietary interventions. However, details about specific nutrients in the diet or supplementation are unclear. We aim to investigate the relationship between nutrient intake and lean mass, function, and strength. Data were derived from the Gothenburg H70 birth cohort study in Sweden, including 719,70-year-olds born in 1944 (54.1% females). For independent variables, the diet history method (face-to-face interviews) was used to estimate habitual food intake during the preceding three months. Dependent variables were gait speed (muscle performance), hand grip strength (muscle strength), and the appendicular lean soft tissue index (ALSTI). Linear regression analyses were performed to analyze the relationship between the dependent variables and each of the covariates. Several nutrients were positively associated with ALSTI, such as polyunsaturated fatty acids (DHA, EPA), selenium, zinc, riboflavin, niacin equivalent, vitamin B12, vitamin D, iron, and protein. After correction for multiple comparisons, there were no remaining correlations with handgrip and gait speed. Findings of positive correlations for some nutrients with lean mass suggest a role for these nutrients in maintaining muscle volume. These results can be used to inform clinical trials to expand the preventive strategies and treatment options for individuals at risk of muscle loss and sarcopenia.

Paediatric dominant and non-dominant handgrip reference curves and the association with body composition

Background Lack of paediatric reference data limits the utility of handgrip strength as a measure of fitness and well-being. Aim To develop paediatric handgrip reference curves and evaluate associations with body size and composition and race/ethnicity group. Subjects and methods Handgrip, body size and composition data were obtained from National Health and Nutrition Examination Survey 2011–2014 participants aged 6–20 years. Densitometry-derived fat and appendicular lean soft tissue mass index Z-scores (FMIZ, ALSTMIZ) were generated in participants >8 years. Dominant and non-dominant handgrip reference curves were created using the LMS method. Analyses included sample weights to produce nationally representative estimates. Results Differences in handgrip strength according to hand dominance increased with age. Handgrip strength was associated with height and arm length Z-scores (R = 0.42 to 0.47) and ALSTMIZ (R = 0.54). Handgrip strength was higher in the non-Hispanic Black group and lower in the Mexican American compared to non-Hispanic White group. Group differences were attenuated when adjusted for height, arm length or ALSTMIZ. Conclusion Paediatric handgrip reference curves were generated from which individual Z-scores can be calculated separately for dominant versus non-dominant hand and adjusted for body size. Association with ALSTMIZ suggests handgrip Z-score may be used as a measure of functional body composition.

Athletic bioimpedance-based equations underestimate fat free mass components in male elite soccer players: development and validation of new soccer-specific predictive models

BackgroundBioelectrical impedance analysis (BIA) is a rapid and user-friendly technique for assessing body composition in sports. Currently, no sport-specific predictive equations are available, and the utilization of generalized formulas can introduce systematic bias. The objectives of this study were as follows: (i) to develop and validate new predictive models for estimating fat-free mass (FFM) components in male elite soccer players; (ii) to evaluate the accuracy of existing predictive equations.MethodsA total of 102 male elite soccer players (mean age 24.7 ± 5.7 years), participating in the Italian first league, underwent assessments during the first half of the in-season period and were randomly divided into development and validation groups. Bioelectrical resistance (R) and reactance (Xc), representing the bioimpedance components, were measured using a foot-to-hand BIA device at a single frequency of 50 kHz. Dual-energy X-ray absorptiometry was employed to acquire reference data for FFM, lean soft tissue (LST), and appendicular lean soft tissue (ALST). The validation of the newly developed predictive equations was conducted through regression analysis, Bland–Altman tests, and the area under the curves (AUC) of regression receiver operating characteristic (RROC) curves.ResultsDeveloped models were: FFM = − 7.729 + (body mass × 0.686) + (stature2/R × 0.227) + (Xc × 0.086) + (age × 0.058), R2 = 0.97, Standard error of estimation (SEE) = 1.0 kg; LST = − 8.929 + (body mass × 0.635) + (stature2/R × 0.244) + (Xc × 0.093) + (age × 0.048), R2 = 0.96, SEE = 0.9 kg; ALST = − 24.068 + (body mass × 0.347) + (stature2/R × 0.308) + (Xc × 0.152), R2 = 0.88, SEE = 1.4 kg. Train-test validation, performed on the validation group, revealed that generalized formulas for athletes underestimated all the predicted FFM components (p < 0.01), while the new predictive models showed no mean bias (p > 0.05), with R2 values ranging from 0.83 to 0.91, and no trend (p > 0.05). The AUC scores of the RROC curves indicated an accuracy of 0.92, 0.92, and 0.74 for FFM, LST, and ALST, respectively.ConclusionsThe utilization of generalized predictive equations leads to an underestimation of FFM and ALST in elite soccer players. The newly developed soccer-specific formulas enable valid estimations of body composition while preserving the portability of a field-based method.

Using magnetic resonance imaging to measure head muscles: An innovative method to opportunistically determine muscle mass and detect sarcopenia.

Sarcopenia is associated with multiple adverse outcomes. Traditional methods to determine low muscle mass for the diagnosis of sarcopenia are mainly based on dual-energy X-ray absorptiometry (DXA), whole-body magnetic resonance imaging (MRI) and bioelectrical impedance analysis. These tests are not always available and are rather time consuming and expensive. However, many brain and head diseases require a head MRI. In this study, we aim to provide a more accessible way to detect sarcopenia by comparing the traditional method of DXA lean mass estimation versus the tongue and masseter muscle mass assessed in a standard brain MRI. The H70 study is a longitudinal study of older people living in Gothenburg, Sweden. In this cross-sectional analysis, from 1203 participants aged 70years at baseline, we included 495 with clinical data and MRI images available. We used the appendicular lean soft tissue index (ALSTI) in DXA images as our reference measure of lean mass. Images from the masseter and tongue were analysed and segmented using 3D Slicer. For the statistical analysis, the Spearman correlation coefficient was used, and concordance was estimated with the Kappa coefficient. The final sample consisted of 495 participants, of which 52.3% were females. We found a significant correlation coefficient between both tongue (0.26) and masseter (0.33) with ALSTI (P<0.001). The sarcopenia prevalence confirmed using the alternative muscle measure in MRI was calculated using the ALSTI (tongue=2.0%, masseter=2.2%, ALSTI=2.4%). Concordance between sarcopenia with masseter and tongue versus sarcopenia with ALSTI as reference has a Kappa of 0.989 (P<0.001) for masseter and a Kappa of 1 for the tongue muscle (P<0.001). Comorbidities evaluated with the Cumulative Illness Rating Scale were significantly associated with all the muscle measurements: ALSTI (odds ratio [OR] 1.16, 95% confidence interval [CI] 1.07-1.26, P<0.001), masseter (OR 1.16, 95% CI 1.07-1.26, P<0.001) and tongue (OR 1.13, 95% CI 1.04-1.22, P=0.002); the higher the comorbidities, the higher the probability of having abnormal muscle mass. ALSTI was significantly correlated with tongue and masseter muscle mass. When performing the sarcopenia diagnostic algorithm, the prevalence of sarcopenia calculated with head muscles did not differ from sarcopenia calculated using DXA, and almost all participants were correctly classified using both methods.

Quality of lean body mass and jump capacity in high performance young basketball players lean body mass and jump capacity

ABSTRACTThe lean body mass (LBM) components have been suggested as important predictors of anaerobic performance, which is highly involved in basketball. We explored with descriptive cross-sectional design the relationship between anaerobic performance and full molecular and cellular body composition profile in young male basketball players. Twenty-one players (age = 16.8 ± 1.6 years; body mass = 76.3 ± 15.7 kg, height = 189.3 ± 12.6 cm) were recruited, 11 elite and 10 local level. Participants were evaluated on multicomponent body composition [LBM, appendicular lean soft tissue (ALST), bone mineral content (BMC), total body water (TBW), intracellular water (ICW) and extracellular water (ECW)] and field-based anaerobic performance (vertical jump, linear sprint, and handgrip strength). The stepwise regression analyses adjusted for confounders showed significant relationships of whole-body and regional body composition components with handgrip and jump performance (P ≤ 0.03). Prediction models combining body composition variables assessed by bioimpedance analysis (BIA) and double-energy X-ray absorptiometry (DXA) revealed that lean mass and hydration ratios (ICW/ECW and ECW/TBW) were strongly associated with jump performance (CMJ and CMJ25kg), independently of the competition level (P < 0.01). The novel finding in this study was that water quality (ICW/ECW) and water distribution (ECW/TBW, ICW) of total and regional LBM were the main predictors of vertical jump capacity in young basketball players.

Reference ranges for body composition indices by dual energy X-ray absorptiometry from the Bone Mineral Density in Childhood Study Cohort

BackgroundBody composition assessment aids evaluation of energy stores and the impact of diseases and interventions on child growth. Current United States pediatric reference ranges from the National Health and Nutrition Examination Survey (NHANES) include 20% of children with obesity, body mass index of ≥95th percentile. ObjectivesThis study aimed to develop dual energy X-ray absorptiometry (DXA) based reference ranges in a diverse cohort with low-obesity prevalence from the Bone Mineral Density in Childhood Study (BMDCS). MethodsThis is a secondary analysis of a longitudinal, prospective, observational cohort. Healthy children (height and BMI within 3rd to 97th percentiles, ages 5–19 y at enrollment), from 5 United States centers were measured annually for ≤7 visits. Whole body scans were acquired using Hologic scanners. A subsample underwent repeat measurements to determine precision. We generated reference ranges for appendicular and total lean soft tissue mass index (LSTM Index), fat mass index (FMI), and other body composition measures. Resulting curves were compared to NHANES and across subgroups. Sex and age-specific equations were developed to adjust body composition Z-scores for height Z score. ResultsWe obtained 9846 scans of 2011 participants (51% female, 22% Black, 17% Hispanic, 48% White, 7% Asian/Pacific Islander, and 6% with obesity). Precision (percent coefficient of variation) ranged from 0.7% to 1.96%. Median and–2 standard deviation curves for BMDCS and NHANES were similar, but NHANES +2 standard deviation LSTM Index and FMI curves were distinctly greater than the respective BMDCS curves. Subgroup differences were more extreme for appendicular LSTM Index-Z (mean ± SD: Asian −0.52 ± 0.93 compared with Black 0.77 ± 0.87) than for FMI-Z (Hispanic 0.29 ± 0.98 compared with Black −0.14 ± 1.1) and were smaller for Z-scores adjusted for height Z-score. ConclusionsThese reference ranges add to sparse normative data regarding body composition in children and adolescents and are based on a cohort with an obesity prevalence similar to current BMI charts. Awareness of subgroup differences aids in interpreting results.

Exploring Handgrip Strength as a Cross-cultural Correlate of Body Composition and Upper Body Strength in Older Adults from Costa Rica and Kansas.

Sarcopenia and disability in older adults are often characterized by body composition measurements; however, the gold standard of body composition measurement, dual-energy X-ray absorptiometry (DEXA), is expensive to acquire and maintain, making its use in low and middle income countries (LMIC) it out-of-reach in developing nations. Because these LMIC will bear a disproportionate amount of chronic disease burden due to global aging trends, it is important that reliable, low-cost surrogates need to be developed. Handgrip strength (HGS) is a reliable measure of disability in older adults but has not been used widely in diverse populations. This study compared HGS to multiple measurements of body composition in older adults from the US (Kansas) and a middle-income country (Costa Rica) to test if HGS is a cross-culturally appropriate predictive measure that yields reliable estimates across developed and developing nations. Percent body fat (%BF), lean tissue mass index (LTMI), appendicular lean soft tissue index (ALSTI), body fat mass index (BFMI), bone mineral density (BMD), and HGS were measured in older Costa Ricans (n = 78) and Kansans (n = 100). HGS predicted lean arm mass with equal accuracy for both samples (p ≤ 0.05 for all groups), indicating that it is a reliable, low-cost and widely available estimate of upper body lean muscle mass. Older adults from Costa Rica showed different body composition overall and HGS than controls from Kansas. Handgrip operates equivalently in the US and Mesoamerica and is a valid estimate of lean arm muscle mass as derived by the more expensive DEXA.

Total energy expenditure assessed by 24-h whole-room indirect calorimeter in patients with colorectal cancer: baseline findings from the PRIMe study

BackgroundTotal energy expenditure (TEE) determines energy requirements, but objective data in patients with cancer are limited. ObjectivesWe aimed to characterize TEE, investigate its predictors, and compare TEE with cancer-specific predicted energy requirements. MethodsThis cross-sectional analysis included patients with stages II–IV colorectal cancer from the Protein Recommendation to Increase Muscle (PRIMe) trial. TEE was assessed by 24-h stay in a whole-room indirect calorimeter before dietary intervention and compared with cancer-specific predicted energy requirements (25–30 kcal/kg). Generalized linear models, paired-samples t tests, and Pearson correlation were applied. ResultsThirty-one patients (56 ± 10 y; body mass index [BMI]: 27.9 ± 5.5 kg/m2; 68% male) were included. Absolute TEE was higher in males (mean difference: 391 kcal/d; 95% CI: 167, 616 kcal/d; P < 0.001), patients with colon cancer (mean difference: 279 kcal/d; 95% CI: 73, 485 kcal/d; P = 0.010), and patients with obesity (mean difference: 393 kcal/d; 95% CI: 182, 604 kcal/d; P < 0.001). Appendicular lean soft tissue (β: 46.72; 95% CI: 34.27, 59.17; P < 0.001) and tumor location (colon—β: 139.69; 95% CI: 19.44, 259.95; P = 0.023) independently predicted TEE when adjusted for sex. Error between measured TEE and energy requirements predicted by 25 kcal/kg (mean difference: 241 kcal/d; 95% CI: 76, 405 kcal/d; P = 0.010) or 30 kcal/kg (mean difference: 367 kcal/d; 95% CI: 163, 571 kcal/d; P < 0.001) was higher for patients with obesity, and proportional error was observed (25 kcal/kg: r = −0.587; P < 0.001; and 30 kcal/kg: r = −0.751; P < 0.001). TEE (mean difference: 25 kcal/kg; 95% CI: 24, 27 kcal/kg) was below predicted requirements using 30 kcal/kg (−430 ± 322 kcal/d; P < 0.001). ConclusionsThis is the largest study to assess TEE of patients with cancer using whole-room indirect calorimeter and highlights the need for improved assessment of energy requirements in this population. Energy requirements predicted using 30 kcal/kg overestimated TEE by 1.44 times in a controlled sedentary environment and TEE was outside of the predicted requirement range for most. Special considerations are warranted when determining TEE of patients with colorectal cancer, such as BMI, body composition, and tumor location.This is a baseline cross-sectional analysis from a clinical trial registered at clinicaltrials.gov as NCT02788955 (https://clinicaltrials.gov/ct2/show/NCT02788955).

Low muscle mass, malnutrition, sarcopenia, and associations with survival in adults with cancer in the UK Biobank cohort.

Low muscle mass (MM) is a common component of cancer-related malnutrition and sarcopenia, conditions that are all independently associated with an increased risk of mortality. This study aimed to (1) compare the prevalence of low MM, malnutrition, and sarcopenia and their association with survival in adults with cancer from the UK Biobank and (2) explore the influence of different allometric scaling (height [m2 ] or body mass index [BMI]) on low MM estimates. Participants in the UK Biobank with a cancer diagnosis within 2years of the baseline assessment were identified. Low MM was estimated by appendicular lean soft tissue (ALST) from bioelectrical impedance analysis derived fat-free mass. Malnutrition was determined using the Global Leadership in Malnutrition criteria. Sarcopenia was defined using the European Working Group on Sarcopenia in Older People criteria (version 2). All-cause mortality was determined from linked national mortality records. Cox-proportional hazards models were fitted to estimate the effect of low MM, malnutrition, and sarcopenia on all-cause mortality. In total, 4122 adults with cancer (59.8±7.1years; 49.2% male) were included. Prevalence of low MM (8.0% vs. 1.7%), malnutrition (11.2% vs. 6.2%), and sarcopenia (1.4% vs. 0.2%) was higher when MM was adjusted using ALST/BMI compared with ALST/height2 , respectively. Low MM using ALST/BMI identified more cases in participants with obesity (low MM 56.3% vs. 0%; malnutrition 50% vs. 18.5%; sarcopenia 50% vs. 0%). During a median 11.2 (interquartile range: 10.2, 12.0) years of follow up, 901 (21.7%) of the 4122 participants died, and of these, 744 (82.6%) deaths were cancer-specific All conditions were associated with a higher hazard of mortality using either method of MM adjustment: low MM (ALST/height2 : HR 1.9 [95% CI 1.3, 2.8], P=0.001; ALST/BMI: HR 1.3 [95% CI 1.1, 1.7], P=0.005; malnutrition (ALST/height2 : HR 2.5 [95% CI 1.1, 1.7], P=0.005; ALST/BMI: HR 1.3 [95% CI 1.1, 1.7], P=0.005; sarcopenia (ALST/height2 : HR 2.9 [95% CI 1.3, 6.5], P=0.013; ALST/BMI: HR 1.6 [95% CI 1.0, 2.4], P=0.037). In adults with cancer, malnutrition was more common than low MM or sarcopenia, although all conditions were associated with a higher mortality risk, regardless of the method of adjusting for MM. In contrast, adjustment of low MM for BMI identified more cases of low MM, malnutrition, and sarcopenia overall and in participants with obesity compared with height adjustment, suggesting it is the preferred adjustment.

An elusive consensus definition of sarcopenia impedes research and clinical treatment: A narrative review.

The definition of sarcopenia, the age-related loss of muscle mass, has evolved since the term's inception and yet there is no consensus. Many of the identified definitions of sarcopenia centre their criteria around the loss of muscle mass, loss of function, and weakness. Common variables to various definitions of sarcopenia are appendicular lean soft tissue mass (often called muscle mass), grip strength, and gait speed. However, a lack of consensus remains among operational definitions and diagnostics for this newly recognized disease and may be attributed to the absence of appropriate tools that accurately measure the outcomes of interest, such as skeletal muscle instead of lean mass. In this narrative review, we describe the evolution of the consensus groups' definition of sarcopenia, address the need for more accurate measures of muscle mass and function, and effective, low-cost treatments (i.e., resistance training and diet) for this disease. Consensus on what constitutes sarcopenia is critical to propel research in the field and, importantly, provide what prognostic value a sarcopenia diagnosis provides and how such a patient would be treated.

Normal values for body composition in adults are better represented by continuous reference ranges dependent on age and BMI

Reference values for body composition parameters like skeletal muscle mass index (SMI) depend on age and BMI. To ensure reference intervals reflect these changes, they have traditionally been separated into groups of young adults based on sex and BMI. However, this static stratification oversimplifies the dynamic and gradual changes of body composition with increasing age and BMI. The aim was therefore to provide continuous reference ranges for body composition parameters. Cross-sectional data of 1958 healthy men and women with an age between 18 and 97 years and a BMI between 17.1 und 45.6kg/m2 were obtained between 2011 and 2019. Multiple regression analyses stratified by sex with age, age2 and BMI as independent variables were conducted to predict fat mass index (FMI), visceral adipose tissue (VAT), SMI, appendicular lean soft tissue index (ALSTI) and the ratio between extracellular to total body water (ECW/TBW). The regression models explained between 61 (VAT in women and ALSTI in men) and 93% of the variance in the respective body composition parameters (FMI in women). Age had only a minor impact (2-16%) whereas BMI substantially increased the explained variance of reference models for FMI, VAT and ALSTI (total explained variance 61-93%). In SMI, age is a major determinant of the explained variance (36% in men and 38% in women) with BMI equally contributing to the explained variance (total explained variance 72% in men and 75% in women). For ECW/TBW-ratio, age nearly completely explained the variance (79% in men and 74% in women) whereas BMI added only 2-3% to the explained variance. In conclusion, the derived continuous reference ranges are expected to improve body composition evaluation especially in very overweight and very old persons. Future studies applying these reference equations need to validate these assumptions. STUDY REGISTRATION, CLINICALTRIALS.GOV: NCT01368640, NCT01481285, NCT03779932, NCT04028648.

Multicompartment body composition analysis in older adults: a cross-sectional study

BackgroundDuring aging, changes occur in the proportions of muscle, fat, and bone. Body composition (BC) alterations have a great impact on health, quality of life, and functional capacity. Several equations to predict BC using anthropometric measurements have been developed from a bi-compartmental (2-C) approach that determines only fat mass (FM) and fat-free mass (FFM). However, these models have several limitations, when considering constant density, progressive bone demineralization, and changes in the hydration of the FFM, as typical changes during senescence. Thus, the main purpose of this study was to propose and validate a new multi-compartmental anthropometric model to predict fat, bone, and musculature components in older adults of both sexes.MethodsThis cross-sectional study included 100 older adults of both sexes. To determine the dependent variables (fat mass [FM], bone mineral content [BMC], and appendicular lean soft tissue [ALST]) whole total and regional dual-energy X-rayabsorptiometry (DXA) body scans were performed. Twenty-nine anthropometric measures and sex were appointed as independent variables. Models were developed through multivariate linear regression. Finally, the predicted residual error sum of squares (PRESS) statistic was used to measure the effectiveness of the predicted value for each dependent variable.ResultsAn equation was developed to simultaneously predict FM, BMC, and ALST from only four variables: weight, half-arm span (HAS), triceps skinfold (TriSK), and sex. This model showed high coefficients of determination and low estimation errors (FM: R2adj: 0.83 and SEE: 3.16; BMC: R2adj: 0.61 and SEE: 0.30; ALST: R2adj: 0.85 and SEE: 1.65).ConclusionThe equations provide a reliable, practical, and low-cost instrument to monitor changes in body components during the aging process. The internal cross-validation method PRESS presented sufficient reliability in the model as an inexpensive alternative for clinical field use.

High-intensity interval aerobic and resistance training to counteract low relative lean soft tissue mass in middle age: A randomized controlled trial

BackgroundAge-related loss of skeletal muscle mass and function begins in early middle age, yet research to date has focused on older individuals, limiting our understanding of interventions earlier in the lifespan. To date, no high-intensity interval training studies have been conducted in middle-aged adults with low relative lean soft tissue mass. MethodsEighty-two middle-aged adults (40–50 years of age) with low appendicular lean soft tissue mass index confirmed with dual energy x-ray absorptiometry (DXA) were randomly allocated (1:1) to group-based, 20-week, three times a week, high-intensity aerobic and resistance training (HIART) program or 60-min education session (Control). The primary outcome was change in total lean soft tissue mass measured by DXA. Secondary outcomes included cardiorespiratory fitness, physical function (handgrip strength, gait speed, 30-seconds sit-to-stand, quadriceps strength and muscle quality). Measures were obtained at baseline (0 weeks), mid-intervention (10 weeks) and post-intervention (20 weeks). ResultsMean age in HIART was 44.8 (SD 3.2) and 45.4 (SD 2.9) in Control group. The majority of the participants were female with 88 % in HIART and 83 % in Control group. Mean BMI in HIART was 25.8 kg/m2 (SD 3.5) and 26.4 kg/m2 (SD 4.1) Control group. Intention to treat analysis showed that post-intervention, HIART increased significantly more total lean soft tissue mass (0.8 kg, 95%CI 0.15, 1.46), appendicular lean soft tissue mass index (0.2 kg/m2, 95%CI 0.09, 0.33), peak oxygen uptake (5.18 mL/min/kg, 2.97 to 7.39 95%CI), grip strength (2.2 kg, 95%CI 0.09, 4.32), and 30-s sit-to-stand (1.3 times, 95%CI 0.43, 2.12) with significantly greater reductions in body fat percentage (−1.1 %, 95%CI −2.03, −0.10) and maximum gait speed (−0.2 m/s, 95 % CI -0.34, −0.03) compared Control. ConclusionThe HIART program is an effective exercise intervention to increase total lean soft tissue mass in middle-aged adults with low relative lean soft tissue mass compared to a waitlist control group.

Muscular strength and skeletal muscle mass in 511 physically independent older women aged 60-88years.

Although one-repetition maximum (1RM) and lean soft tissue (LST) are the most common measures to assess muscular strength and skeletal muscle mass in older adults, reference data is still missing. Therefore, the present study aimed to produce reference values for the 1RM tests and LST in physically independent older women. Furthermore, the effect of age and body segment on these outcomes was examined. Five hundred and eleven older women aged 60-88years participated in the present study. The 1RM tests were performed on chest press, leg extension, and preacher curl exercises. Dual-energy X-ray absorptiometry exams were used to determine total and segmental LST. The 1RM and LST average values: chest press=44.0±11.1kg, leg extension=48.8±11.8kg, preacher curl=21.6±5.4kg; trunk LST=19.0±2.7kg, lower-limbs LST=12.5±1.9kg, upper-limbs LST=4.0±0.7kg, appendicular LST=16.6±2.6, total LST=38.5±5.2kg. The age-related declines in 1RM chest press and leg extension were higher than in preacher curl. The present study provides reference values for 1RM of different body segments and total and segmental LST in older women. In addition, our results revealed a reduction of muscular strength and LST with increasing age, and the magnitude of the age-related strength reduction depends on the body segment analyzed.

THU396 - Metabolic associated fatty liver disease is associated with appendicular lean soft tissue abnormalities in patients with chronic hepatitis B

THU396 - Metabolic associated fatty liver disease is associated with appendicular lean soft tissue abnormalities in patients with chronic hepatitis B

MRI thigh measurements predict whole‐body skeletal muscle mass in patients with type 2 diabetes: a comparison with DXA

AbstractBackgroundSarcopenia is an age‐related loss of skeletal muscle mass (SMM) and function, associated with falls, frailty, and functional decline. It is more prevalent and often accelerated in people with Type 2 diabetes (T2D), especially when co‐existing with obesity (sarcopenic obesity). Accurate whole‐body SMM measurement, feasible using dual‐energy X‐ray absorptiometry (DXA) or magnetic resonance imaging (MRI), has utility both in clinical practice and in epidemiological and mechanistic research, considering the dual mechanical and metabolic function of skeletal muscle. Compared with MRI, DXA may underestimate age‐related muscle mass by up to 30%, and so direct comparison of DXA/MRI‐derived SMM measurements may be invalid in patients with obesity and T2D, who have potentially even more pronounced sarcopenia/sarcopenic obesity. We aimed to validate single‐slice or multiple‐slice measures of SMM, using MRI, with whole‐body SMM measures derived from DXA scans of appendicular lean soft tissue, specifically in patients with obesity and T2D.MethodsWe undertook a cross‐sectional study in which we performed paired DXA and whole‐body 3.0‐T MRI on 36 people with T2D and obesity (body mass index [BMI] &gt; 30 kg/m2). Single‐slice and seven‐slice estimates of muscle mass, taken from mid‐thigh/thigh MRI images, respectively, were determined, and compared with whole‐body SMM derived from DXA scans of appendicular lean soft tissue, in men and women separately.ResultsSeventeen men (age 48.4 ± 8.2 years, BMI 37.5 ± 5.1 kg/m2, body fat 39.1 ± 6.0%) and 19 women (age 51.8 years ± 9.7, BMI 37.8 ± 5.8 kg/m2, body fat 47.6 ± 5.1%) were recruited. Whole‐body SMM estimated by seven‐slice thigh MRI correlated strongly with DXA‐derived SMM in both men (r = 0.94, P &lt; 0.001) and women (r = 0.94, P &lt; 0.001). Single‐slice thigh estimates of whole‐body SMM by MRI also showed strong relationships to DXA‐derived SMM in both men (r = 0.88, P &lt; 0.001) and women (r = 0.87, P &lt; 0.001). There was no evidence of a statistically significant difference when comparing the performance of using single‐slice vs. multiple‐slices to determine SMM (P = 0.10 for males and P = 0.13 for females).ConclusionsThis study demonstrates that accurate determination of whole‐body SMM is possible using either single‐slice mid‐thigh or seven‐slice thigh MRI in men and women with obesity and T2D in whom there may be significant alterations in body composition. Its application may be of use clinically and in obesity‐related, metabolic, and gerontological research where accurate assessments of body composition add mechanistic insight.

Association of Low Muscle Mass With Cognitive Function During a 3-Year Follow-up Among Adults Aged 65 to 86 Years in the Canadian Longitudinal Study on Aging

Cross-sectional studies have shown that combined low muscle mass and strength are associated with cognitive impairment. Whether low muscle mass, reflective of physiologic reserve, is independently associated with faster cognitive decline remains unknown. To investigate the associations between low muscle mass and cognitive decline in 3 distinct domains among adults aged at least 65 years. The Canadian Longitudinal Study on Aging is a prospective population-based cohort study of community-dwelling adults. Enrollment occurred from 2011 to 2015 with a 3-year follow-up. Analyses for this study were conducted on those aged at least 65 years from April 24 to August 12, 2020. Appendicular lean soft tissue mass (ALM) was assessed by dual energy x-ray absorptiometry. Low ALM was identified using the sex-specific Canadian cut points. Memory was assessed using the Rey auditory verbal learning test. Executive function was assessed using the mental alternation test, Stroop high interference (words/dot) test, the animal fluency test, and the controlled oral word association test. Psychomotor speed was assessed using computer-administered choice reaction time. Composite scores by domain were created. Of 8279 participants, 4003 (48%) were female, 8005 (97%) were White, and the mean (SD) age was 72.9 (5.6) years. A total of 1605 participants (19.4%) had low ALM at baseline. Participants with low ALM were older, had lower body mass index and physical activity level. The presence of low ALM at baseline was associated with faster 3-year cognitive decline in executive functions and psychomotor speed from multiple linear regressions. After adjusting for covariates including age, level of education, percentage body fat, and handgrip strength, low ALM remained independently associated with executive function decline (standardized β: -0.032; P = .03) only. Low ALM was not associated with memory. This cohort study found longitudinal associations between low ALM and cognition in aging. Identification of older adults with low muscle mass, a targetable modifiable factor, may help estimate those at risk for accelerated executive function decline. Further longer-term investigation of associations is warranted.

Male and female athletes matched for maximum oxygen uptake per skeletal muscle mass: equal but still different.

We matched highly trained competitive male and female athletes using maximal oxygen uptake (V̇O<inf>2max</inf>) per kg skeletal muscle mass (SMM) to show sex differences in factors limiting V̇O<inf>2max</inf>. Thirteen highly trained male (28±3.0 yr) vs. 13 female (21.3±3.0 yr) endurance athletes and 10 male (23.9±3.8 yr) vs. 10 female sprinters (21.9±3.3 yr) performed an incremental running treadmill test until exhaustion. Main cardiorespiratory variables were measured using ergospirometry. SMM was determined using the dual X-ray absorptiometry method and a regression equation based on measured appendicular lean soft tissue. Basic hematological parameters were obtained from capillary blood samples taken before exercise. In both endurance and sprint groups, male athletes had significantly higher muscle mass (by 8-12%) and substantially lower total fat (by 55-58%). For almost all body composition indicators, the effect size of sex differences was very large (Cohens d>1.4). Male athletes obtained significantly higher values in cardiorespiratory variables (by 12-34%) and factors related to oxygen transport (9-13%). Cohens d of the revealed differences was large or very large in both groups (0.8-2.1 in sprinters and 0.8-2.3 in endurance athletes). Male and female competitive athletes having the same V̇̇O<inf>2max</inf> per kg SMM strongly differ in main factors limiting maximum oxygen uptake. These differences are more pronounced in endurance- than in sprint-trained athletes. The strongest differences are seen for body composition (fat, lean, and muscle mass) and central cardiac factors.

Phenotypic differences between people varying in muscularity.

BackgroundBody mass is the primary metabolic compartment related to a vast number of clinical indices and predictions. The extent to which skeletal muscle (SM), a major body mass component, varies between people of the same sex, weight, height, and age is largely unknown. The current study aimed to explore the magnitude of muscularity variation present in adults and to examine if variation in muscularity associates with other body composition and metabolic measures.MethodsMuscularity was defined as the difference (residual) between a person's actual and model‐predicted SM mass after controlling for their weight, height, and age. SM prediction models were developed using data from a convenience sample of 492 healthy non‐Hispanic (NH) White adults (ages 18–80 years) who had total body SM and SM surrogate, appendicular lean soft tissue (ALST), measured with magnetic resonance imaging and dual‐energy X‐ray absorptiometry, respectively; residual SM (SMR) and ALST were expressed in kilograms and kilograms per square meter. ALST mass was also evaluated in a population sample of 8623 NH‐White adults in the 1999–2006 National Health and Nutrition Examination Survey. Associations between muscularity and variation in the residual mass of other major organs and tissues and resting energy expenditure were evaluated in the convenience sample.ResultsThe SM, on average, constituted the largest fraction of body weight in men and women up to respective BMIs of 35 and 25 kg/m2. SM in the convenience sample varied widely with a median of 31.2 kg and an SMR inter‐quartile range/min/max of 3.35 kg/−10.1 kg/9.0 kg in men and 21.1 kg and 2.59 kg/−7.2 kg/7.5 kg in women; per cent of body weight as SM at 25th and 75th percentiles for men were 33.1% and 39.6%; corresponding values in women were 24.2% and 30.8%; results were similar for SMR indices and for ALST measures in the convenience and population samples. Greater muscularity in the convenience sample was accompanied by a smaller waist circumference (men/women: P < 0.001/=0.085) and visceral adipose tissue (P = 0.014/0.599), larger liver (P = 0.065/<0.001), kidneys (P = 0.051/<0.009), and bone mineral (P < 0.001/<0.001), and larger magnitude resting energy expenditure (P < 0.001/<0.001) than predicted for the same sex, age, weight, and height.ConclusionsMuscle mass is the largest body compartment in most adults without obesity and is widely variable in mass across people of similar body size and age; and high muscularity is accompanied by distinct body composition and metabolic characteristics. This previously unrecognized heterogeneity in muscularity in the general population has important clinical and research implications.