Comparison of skeletal muscle mass to fat-free mass ratios among different ethnic groups

Establishing age and gender-specific serum creatinine reference ranges for Thai pediatric population

Accurate assessment of kidney function in children requires age and gender-specific reference ranges for serum creatinine. Traditional reference values, often derived from adult populations and different ethnic backgrounds, may not be suitable for children. This study aims to establish specific reference ranges for serum creatinine in the Thai pediatric population, addressing the gap in localized and age-appropriate diagnostic criteria. This retrospective study analyzed serum creatinine levels from Thai children aged newborn to 18 years, collected from the Laboratory Information System of the Queen Sirikit National Institute of Child Health from January 2017 to December 2021. The Bhattacharya method was employed to establish reference ranges, considering different age groups and genders. The study compared these newly established reference values with international studies, including those of Schlebusch H., Pottel H., and Chuang GT., to validate their relevance and accuracy. A total of 27,642 data entries (15,396 males and 12,246 females) were analyzed. The study established distinct reference ranges for serum creatinine, which varied significantly across different age groups and between genders. These ranges were found to gradually increase with age from 2 months to 18 years. The study also highlighted notable differences in reference values when compared with other ethnic populations. The study successfully establishes tailored reference ranges for serum creatinine in Thai children, providing a valuable tool for more accurate diagnosis and monitoring of kidney health in this demographic. This initiative marks a significant advancement in pediatric nephrology in Thailand and suggests a need for continuous refinement of these ranges and further research in this area.

Accurate estimation of skeletal muscle mass by comparison of computed tomographic images of the third lumbar and third cervical vertebrae in Japanese patients with oral squamous cell carcinoma

OBJECTIVES

We evaluated the accuracy of estimating the cross-sectional area (CSA) at the third lumbar vertebra (L3) based on the CSA at the third cervical vertebra (C3) using computed tomographic images, and we identified the sources of error and bias using the evaluation of absolute reliability in 89 Japanese patients with oral squamous cell carcinoma.

METHODS

Skeletal muscle CSA was measured at the C3 and L3 on pretreatment computed tomographic images. We used the CSA at the C3 to estimate CSA at the L3 in an existing prediction formula. Correlation coefficients were used to evaluate the relative reliability of the estimate, and Bland-Altman analysis and minimum detectable change (MDC) were used to evaluate its absolute reliability.

RESULTS

Estimated and actual CSAs at L3 were strongly correlated (r = 0.885, p < 0.001). The mean difference between the estimated and actual CSAs was - 1.0887 cm², the 95% confidence interval was - 4.09 to 1.91 cm² (p = 0.472), and the 95% limits of agreement were - 29.0 and 26.8 cm². The MDC at the 95% level of confidence in estimated and actual CSAs was 27.9 cm².

CONCLUSIONS

The estimation of CSA at the L3 from the existing prediction formula with the CSA at the C3 had no systematic biases, but it did have random errors. Random errors resulted from measurement errors and biological variation. Usefulness of the existing formula is limited by physical differences in populations.

Sarcopenia in Children with Solid Organ Tumors: An Instrumental Era

Sarcopenia has recently been studied in both adults and children and was found to be a prognostic marker for adverse outcome in a variety of patient groups. Our research showed that sarcopenia is a relevant marker in predicting outcome in children with solid organ tumors, such as hepatoblastoma and neuroblastoma. This was especially true in very ill, high-risk groups. Children with cancer have a higher likelihood of ongoing loss of skeletal muscle mass due to a mismatch in energy intake and expenditure. Additionally, the effects of cancer therapy, hormonal alterations, chronic inflammation, multi-organ dysfunction, and a hypermetabolic state all contribute to a loss of skeletal muscle mass. Sarcopenia seems to be able to pinpoint this waste to a high degree in a new and objective way, making it an additional tool in predicting and improving outcome in children. This article focuses on the current state of sarcopenia in children with solid organ tumors. It details the pathophysiological mechanisms behind sarcopenia, highlighting the technical features of the available methods for measuring muscle mass, strength, and function, including artificial intelligence (AI)-based techniques. It also reviews the latest research on sarcopenia in children, focusing on children with solid organ tumors.

3D visualisation of psychometric estimates for the ideal male body

Psychological concerns are frequently indexed by psychometric questionnaires but the mental representations that they seek to quantify are difficult to visualise. We used a set of questionnaires designed to measure men's concept of their bodies including: the Drive for Muscularity Scale (DMS; McCreary & Sasse, 2000), the Perceived Sociocultural Pressures Scale (PSPS; Stice, Nemeroff, & Shaw, 1996a), the Body Appreciation Scale (BAS-2; Tylka & Wood-Barcalow, 2015), and the Sociocultural Attitudes Towards Appearance Questionnaire-3 (SATAQ-3; Thompson, van den Berg, Roehrig, Guarda, & Heinberg, 2004). We combined their use with an interactive 3D modelling programme to allow men to create computer-generated representations of their ideal bodies. We used a principal component analysis to extract those shape components of our participants' CGI ideal bodies that were predicted by the questionnaires and reconstructed the body shapes that these questionnaires were capturing. Moving from the lowest to the highest score on both the DMS and SATAQ corresponded with changes in muscularity, particularly muscle mass and definition. This approach allows us to demonstrate the actual body features that are being captured by a particular questionnaire.

Factors Underlying Bench Press Performance in Elite Competitive Powerlifters

ABSTRACT

Reya, M, Škarabot, J, Cvetičanin, B, and Šarabon, N. Factors underlying bench press performance in elite competitive powerlifters. J Strength Cond Res 35(8): 2179-2186, 2021-Previous investigations of 1 repetition maximum bench press (1RM BP) performance have been either descriptive or have explored a limited number of contributing variables. The purpose of this study was to investigate the interplay between structural, technical, and neuromuscular factors in relation to 1RM BP in competitive powerlifters. Thirteen national and international level male powerlifters (26 ± 9 years, 178 ± 6 cm, and 93.8 ± 9.9 kg) visited the laboratory twice. Anthropometric and ultrasound measures were taken on the first visit, whereas performance measures (voluntary activation level, isokinetic strength, and kinetic, kinematic, and electromyographic measurements during 1RM BP) were recorded on the second visit. Correlation and multiple regression were used to investigate the contribution of structural, technical, and neuromuscular variables to 1RM BP corrected for body mass using the Wilks coefficient. The highest degree of association was shown for structural (lean and bone mass, brachial index, arm circumference, and agonist cross-sectional area [CSA]; r = 0.58-0.74) followed by neuromuscular factors (elbow and shoulder flexion strength; r = 0.57-0.71), whereas technical factors did not correlate with 1RM BP performance (r ≤ 0.49). The multiple regression showed that lean body mass, brachial index, and isometric shoulder flexion torque predicted 59% of the common variance in 1RM BP. These data suggest that in a sample of elite competitive powerlifters, multiple factors contribute to 1RM BP with variables such as lean body mass, the agonist CSA, brachial index, and strength of the elbow and shoulder flexors being the greatest predictors of performance.

Feasibility of assessment of skeletal muscle mass on a single cross-sectional image at the level of the fourth thoracic vertebra

BACKGROUND

Skeletal muscle mass (SMM) determined on computed tomography (CT) is emerging as a novel imaging biomarker. Cross-sectional area (CSA) of SMM at the level of the third lumbar vertebra (L3) on abdominal imaging is considered the clinical reference standard for measuring SMM. In certain patient groups, such as those with oncological or non-oncological lung disease like COVID-19, a chest CT may be available while an abdominal CT is not. The purpose of this study was to investigate whether determining SMM on a chest CT is a feasible alternative to abdominal CT.

RESEARCH QUESTION

What is the correlation between SMM measurements at the level of L3 and the level of the fourth thoracic vertebra (Th4)?

STUDY DESIGN AND METHODS

In this study we retrospectively analyzed abdominal and thoracic series of whole-body CT-scans of trauma patients (N = 47) and head and neck cancer patients (N = 194). All abdominal muscles were delineated on a single axial slice at the level of L3. The erector spinae, levator scapulae, rhomboideus minor and major and pectoralis minor and major muscles were delineated on a single axial slice at the level of Th4. CSA of the muscles at Th4 and the L3 level were compared using linear regression, and a multivariate linear regression model was established.

RESULTS

Muscle CSA at level Th4 strongly correlates with L3 muscle CSA (r = 0.791, p < 0.05). A multivariate model incorporating the patient characteristics arm positioning, age, sex, and weight achieved a stronger correlation (r = 0.856, p < 0.05).

INTERPRETATION

Skeletal muscle CSA measured at the level of Th4 is a feasible alternative to measurements at L3. This allows diagnosing low SMM using clinically available thoracic CT-scans. SMM measurements at the level of Th4 may become a prognostic or triage tool when faced with mechanical ventilator shortage.

Assessing skeletal muscle mass based on the cross-sectional area of muscles at the 12th thoracic vertebra level on computed tomography in patients with oral squamous cell carcinoma

OBJECTIVES

This study aimed to create a formula to estimate the third lumbar vertebra (L3)¹ level skeletal muscle cross-sectional area (CSA), known as a standard value to evaluate skeletal muscle mass on computed tomography (CT), using the twelfth thoracic vertebra (Th12) level skeletal muscle CSA on chest CT.

MATERIALS AND METHODS

This retrospective observational study included patients aged 40 + years with a diagnosis of oral squamous cell carcinoma (n = 164). Skeletal muscle CSA on CT images was measured using the Th12 and the L3 levels of pretreatment CT scans. The predictive formula was created based on the five-fold cross-validation method with a linear regression model. Correlations between the predicted L3-level CSA and the actual L3-level CSA were evaluated using r and Intraclass Correlation Coefficients (ICC).

RESULTS

The predictive formula for L3-level CSA from Th12-level CSA was: CSA at L3 (cm²) = 14.143 + 0.779 * CSA at Th12 (cm²) - 0.212 * Age (y) + 0.502 * Weight (kg) + 13.763 * Sex. Correlations between the predicted and measured L3-level CSA were r = 0.915 [0.886-0.937] and ICC = 0.911 [0.881-0.934].

CONCLUSION

We developed a formula for predicting skeletal muscle mass from the Th12-level CT slice. The predicted L3-level CSA correlated with the measured L3-level CSA.

Extreme skeletal muscle loss during induction chemotherapy is an independent predictor of poor survival in advanced epithelial ovarian cancer patients

AIM

Skeletal muscle loss is often observed in advanced cancer patients. This study investigates whether skeletal muscle loss is associated with survival outcomes of advanced epithelial ovarian cancer (EOC) patients after induction chemotherapy (IC) in a Japanese cohort. Whether serum inflammatory markers are associated with skeletal muscle changes is also addressed.

METHODS

We retrospectively reviewed 60 patients with stage III/IV EOC who underwent IC between 2010 and 2017. Skeletal muscle area (SMA) was measured at the third lumbar vertebrae level on a single axial computed tomography-scan image. Receiver operating curve analysis was used to determine cut-off values of pre- and post-IC SMA and SMA ratio (SMAR). Univariate and multivariate analyses of overall survival (OS) were conducted using the log-rank test and Cox proportional hazards regression model, respectively.

RESULTS

The SMA decreased significantly after IC (P = 0.019). The cut-off value between low and high SMAR was 0.96. High or low SMAR was observed in 34 (57%) and 26 (43%) patients, respectively. Univariate analysis revealed that low SMAR was associated with poor OS (P = 0.025). Multivariate analysis showed that incomplete resection during interval debulking surgery (hazard ratio, 0.30; 95% CI, 0.11-0.80; P = 0.016) and a low SMAR (hazard ratio, 3.17; 95% CI, 1.18-9.06; P = 0.022) were independent predictors of poor OS. Of the serum inflammatory markers investigated, only post-IC absolute neutrophil count correlated significantly with SMAR (P = 0.012).

CONCLUSION

Low SMAR can be used to predict poor prognosis in advanced EOC patients who have undergone IC.

Brazilian Nutritional Consensus in Hematopoietic Stem Cell Transplantation: Adults

The nutritional status of patients submitted to hematopoietic stem cell transplant is considered an independent risk factor, which may influence on quality of life and tolerance to the proposed treatment. The impairment of nutritional status during hematopoietic stem cell transplant occurs mainly due to the adverse effects resulting from conditioning to which the patient is subjected. Therefore, adequate nutritional evaluation and follow-up during hematopoietic stem cell transplant are essential. To emphasize the importance of nutritional status and body composition during treatment, as well as the main characteristics related to the nutritional assessment of the patient, the Brazilian Consensus on Nutrition in Hematopoietic Stem Cell Transplant: Adults was prepared, aiming to standardize and update Nutritional Therapy in this area. Dietitians, nutrition physicians and hematologists from 15 Brazilian centers thar are references in hematopoietic stem cell transplant took part.

Ultrasound-Derived Forearm Muscle Thickness Is a Powerful Predictor for Estimating DXA-Derived Appendicular Lean Mass in Japanese Older Adults

To test the validity of published equations, anterior forearm muscle thickness (MT-ulna) of 158 Japanese older adults (72 men and 86 women) aged 50-79 y was measured with ultrasound. Appendicular lean soft tissue mass (aLM) was estimated from MT-ulna using two equations (body height without [eqn 1] and with [eqn 2]) previously published in the literature. Appendicular lean mass was measured using dual-energy X-ray absorption (DXA), and this method served as the reference criterion. There was a strong correlation between DXA-derived and ultrasound-estimated aLM in both equations (r = 0.882 and r = 0.944). Total error was 2.60 kg for eqn (1) and 1.38 kg for eqn (2). A Bland-Altman plot revealed that there was no systematic bias between DXA-derived and ultrasound-estimated aLM; however, eqn (1) overestimated aLM compared with DXA-derived aLM. Our results suggest that an ultrasound MT-ulna equation that includes body height is appropriate and useful for estimating aLM in Japanese adults.

Interethnic differences in pharmacokinetics of antibacterials

BACKGROUND

Optimal antibacterial dosing is imperative for maximising clinical outcome. Many factors can contribute to changes in the pharmacokinetics of antibacterials to the extent where dose adjustment may be needed. In acute illness, substantial changes in important pharmacokinetic parameters such as volume of distribution and clearance can occur for certain antibacterials. The possibility of interethnic pharmacokinetic differences can further complicate attempts to design an appropriate dosing regimen. Factors of ethnicity, such as genetics, body size and fat distribution, contribute to differences in absorption, distribution, metabolism and elimination of drugs. Despite extensive previous work on the altered pharmacokinetics of antibacterials in some patient groups such as the critically ill, knowledge of interethnic pharmacokinetic differences for antibacterials is limited.

OBJECTIVES

This systematic review aims to describe any pharmacokinetic differences in antibacterials between different ethnic groups, and discuss their probable mechanisms as well as any clinical implications.

METHODS

We performed a structured literature review to identify and describe available data of the interethnic differences in the pharmacokinetics of antibacterials.

RESULTS

We found 50 articles that met our inclusion criteria and only six of these compared antibacterial pharmacokinetics between different ethnicities within the same study. Overall, there was limited evidence available. We found that interethnic pharmacokinetic differences are negligible for carbapenems, most β-lactams, aminoglycosides, glycopeptides, most fluoroquinolones, linezolid and daptomycin, whereas significant difference is likely for ciprofloxacin, macrolides, clindamycin, tinidazole and some cephalosporins. In general, subjects of Asian ethnicity achieve drug exposures up to two to threefold greater than Caucasian counterparts for these antibacterials. This difference is caused by a comparatively lower volume of distribution and/or drug clearance.

CONCLUSION

Interethnic pharmacokinetic differences of antibacterials are likely; however, the clinical relevance of these differences is unknown and warrants further research.

Validity of ultrasound prediction equations for total and regional muscularity in middle-aged and older men and women

To test the validity of published equations, 79 Caucasian adults (40 men and 39 women) aged 50-78 y had muscle thickness (MT) measured by ultrasound at nine sites of the body. Fat-free mass (FFM), lean soft tissue mass (LM) and total muscle mass (TMM) were estimated from MT using equations previously published in the literature. Appendicular LM (aLM) was estimated using dual-energy X-ray absorptiometry (DXA) and this method served as the reference criterion. There were strong correlations (range r = 0.85-0.94) between DXA-derived aLM and estimated FFM, leg LM or TMM. Total error between DXA-derived aLM and TMM (∼2 kg) was lower compared with the three other selected equations (6-10 kg). A Bland-Altman plot revealed that there was no systematic bias between aLM and TMM; however, the other three equations included systematic error. Our results suggest that an ultrasound equation for TMM is appropriate and useful for evaluating skeletal muscle mass in the body.

The significance of body mass index in calculating the cut-off points for low muscle mass in the elderly: methodological issues

OBJECTIVES

Cut-off points (COPs) for appendicular lean mass (ALM) index, essential to define low muscle mass (LMM) in the elderly, have never been officially defined for Poland. The aim of the study was to establish them. Additionally, the significance of body mass index (BMI) for correctly defining the COPs in a young, healthy reference group was assessed.

METHODS

The study was composed of reference group (n = 1113) and the elderly group (n = 200). In all subjects, body composition was assessed by bioimpedance analysis, and ALM index was calculated. Next, COPs (kg/m(2)) were set up for the whole reference group and for particular subgroups with different BMIs separately. They were used to diagnose sarcopenia in the elderly.

RESULTS

COP for all young females was 5.37 (COP-F), while it was equal to 5.52 (COP-F2) when only those with a recommended BMI (18.50-24.99 kg/m(2)) were taken into consideration. For males, it was 7.32 and 7.29, respectively. Only 7% of elderly females had LMM based on COP-F and 15% had LMM based on COP-F2 (P < 0.05); for males, the percentages were 18% and 16%, respectively.

CONCLUSIONS

COPs for LMM for Poland are 5.52 kg/m(2) (females) and 7.29 kg/m(2) (males). The reference group BMI is an important factor in establishing COPs for low muscle mass.

Prevalence of site-specific thigh sarcopenia in Japanese men and women

The purpose of this study was to compare the prevalence of severe sarcopenia detected by total skeletal muscle mass (SM) index and of site-specific thigh sarcopenia for differing age groups in men and women. Japanese nonobese men and women aged 20 to 85 (n = 1,994, 55 % women) had muscle thickness (MTH) measured by ultrasound at six sites on the anterior and posterior aspects of the body. SM was estimated from ultrasound-derived prediction equations. Site-specific thigh sarcopenia was calculated using ultrasound-measured MTH at the anterior and posterior aspects of the thigh (MTH ratio, anterior 50 %/posterior 50 % thigh MTH (A50/P50 MTH)). Sarcopenia was defined as a SM index (SM divided by height(2)) of >2 standard deviations (SD) below the mean for young adults. Site-specific thigh sarcopenia was defined as a ratio of A50/P50 MTH of >2 SD below the mean for young adults. Age was inversely correlated to SM index and A50/P50 MTH in men (r = -0.480 and r = -0.522) and women (r = -0.243 and r = -0.516). The prevalence rate of sarcopenia was less than 3 % for women under the age of 60, 7 % for ages 60-69, and 24 % for ages 70-80. In men, the prevalence rate of sarcopenia was less than 7 % under the age of 50, 18 % for ages 50-59, 33 % for ages 60-69, and 47 % for ages 70-85. Compared to the sarcopenia estimated by SM index, there was a higher prevalence of site-specific thigh sarcopenia observed in both sexes. These results suggest that site-specific thigh sarcopenia appears before it is able to be detected at the whole body level.

Precision of total and regional body fat estimates from dual-energy X-ray absorptiometer measurements

OBJECTIVES

To evaluate the precision of both total %fat and all the regional %fat measures acquired from both the Lunar Prodigy and Lunar iDXA software.

DESIGN

Cross-sectional study.

SETTING

University-based research laboratory.

PARTICIPANTS

The sample consisted of 300 individual test records from men and women who had volunteered to participate in dual-energy x-ray absorptiometer (DXA) technician precision training studies. Subjects ranged in age from 20-84 years and in body mass index from 15.7-52.0 kg.m-2.

MEASUREMENTS

A total of 27 different technicians performed three total body scan measurements on 10-15 different subjects. The Lunar Prodigy and Lunar iDXA were used for 253 and 47 precision training evaluations, respectively. The regions of interest (ROI) were automatically determined by the enCORE software (autoROI) for total body, android, gynoid, trunk, legs, and arms regions and the region %fat data were used for analyses.

RESULTS

The CV for total body %fat was 1.9% and 0.9% for the Prodigy and iDXA, respectively. CV's for %fat measures at regional sites ranged from 1.2-4.4% for the Prodigy measures and 0.9-2.4% for the iDXA measures. The ICC for both devices ranged from 0.990 to 0.999.

CONCLUSION

Monitoring the status of body composition changes with age is gaining more clinical acceptance. Thus, it is important that practitioners use measures that are both precise and accurate. The findings from the current study add support that DXA measurements can be used with a high level of confidence for serial testing of patients.

Applicability of ultrasound muscle thickness measurements for predicting fat-free mass in elderly population

OBJECTIVE

This study aimed to examine the applicability of ultrasound muscle thickness (MT) measurements for predicting whole body fat-free mass (FFM) in elderly individuals.

DESIGN AND SETTING

Cross-sectional study of 77 healthy elderly individuals.

METHODS

MTs at nine sites of the body and FFM were determined using B-mode ultrasound and dual-energy x-ray absorptiometry (DXA), respectively, in 44 women and 33 men aged 52 to 78 yrs. Stepwise multiple regression analysis produced two equations for predicting DXA-based FFM with sex (dummy: woman = 0 and man = 1) and either MTs at the anterior and posterior of thigh and lower leg (Eq1) or the product of MT and limb length (MT×LL) at thigh anterior and posterior, lower leg posterior, and upper arm anterior (Eq2) as independent variables.

RESULTS

The R2 and SEE for each of the two equations were 0.929 and 2.5 kg for Eq1 and 0.955 and 2.0 kg for Eq2. The estimated FFM from each of Eq1 (44.4 ± 8.9 kg) and Eq2 (44.4 ± 9.0 kg) did not significantly differ from that of the DXA-based FFM (44.4 ± 9.2 kg), without systematic error. However, the absolute value of the difference between the DXA-based and estimated FFM was significantly greater with Eq1 (2.0 ± 1.5 kg) than with Eq2 (1.5 ± 1.3 kg).

CONCLUSION

The current results indicate that ultrasound MT measurement is useful to predict FFM in the elderly, and its accuracy is improved by using the product of MT and limb length as an independent variable.