Development of methods for body composition studies

Development and validation of a new anthropometric equation to predict skeletal muscle mass in a heterogeneous caucasian population

Assessment of skeletal muscle mass (SMM) is essential to monitor physical performance and health status. The most widely used anthropometric equations have repeatedly demonstrated to overestimate or underestimate SMM in different populations. Herein, we developed and cross-validated a new anthropometric regression equation for estimating SMM, using dual-energy X-ray absorptiometry (DXA) as the reference method. A group of 206 healthy Caucasian participants aged 18-65 years were included in the final analysis. Participants underwent a DXA scan, and body mass, stature, four skinfolds (biceps, triceps, subscapular, and supracrestal) and four breadths (femoral, humeral, ankle, and wrist) were assessed by an accredited anthropometrist. Accuracy was assessed by mean differences, coefficient of determination, standard error of the estimate (SEE), concordance correlation coefficient (CCC), and Bland-Altman plots. The proposed equation explained 91.3% of the variance in the DXA-derived SMM percentage, with a low random error (SEE = 1.95%), and a very strong agreement (CCC = 0.94). In addition, it demonstrated no fixed or proportional bias and a relatively low individual variability (3.84%). The new anthropometric equation can accurately predict SMM percentage in a Caucasian population with a wide age range (18-65 years).

Sex-Based Effects of Branched-Chain Amino Acids on Strength Training Performance and Body Composition

BACKGROUND

Branched-chain amino acids (BCAAs) are widely studied for their effects on muscle recovery and performance.

AIMS

This study examined the effects of BCAA supplementation on anthropometric data, physical performance, delayed onset muscle soreness (DOMS), and fatigue in recreational weightlifters.

METHODS

The trial involved 100 participants (50 men and 50 women), randomized into BCAA and placebo groups. Subjects in the BCAA group took five daily capsules of 500 mg L-leucine, 250 mg L-isoleucine, and 250 mg L-valine for six months. A two-way ANOVA was used to analyze the main and interaction effects of sex and treatment.

RESULTS

Notable findings include significant improvements in muscle recovery, as indicated by reduced DOMS, particularly in women who showed a decrement of 18.1 ± 9.4 mm compared to 0.8 ± 1.2 mm in the placebo group of a horizontal 100 mm line. Fatigue perception was also significantly lower in the BCAA group, with women reporting a greater decrease (2.6 ± 1.5 scores) compared to the placebo group (0.6 ± 0.7 scores). Strength gains were prominent, especially in men, with a 10% increase in bench press maximum observed in the BCAA group. The interaction between sex and treatment was significant, suggesting sex-specific responses to BCAA supplementation.

CONCLUSIONS

These results underscore the effectiveness of BCAA supplementation in enhancing muscle recovery, reducing fatigue, and improving strength. This study also highlights sex-specific responses, with women benefiting more in terms of DOMS and fatigue reduction, while men experienced greater strength gains, suggesting a need for tailored supplementation strategies.

Glucocorticoid-Induced Myopathy: Typology, Pathogenesis, Diagnosis, and Treatment

Glucocorticoid-induced myopathy is a non-inflammatory toxic myopathy typified by proximal muscle weakness, muscle atrophy, fatigue, and easy fatigability. These vague symptoms coupled with underlying disorders may mask the signs of glucocorticoid-induced myopathy, leading to an underestimation of the disease's impact. This review briefly summarizes the classification, pathogenesis, and treatment options for glucocorticoid-induced muscle wasting. Additionally, we discuss current diagnostic measures in clinical research and routine care used for diagnosing and monitoring glucocorticoid-induced myopathy, which includes gait speed tests, muscle strength tests, hematologic tests, bioelectrical impedance analysis (BIA), dual-energy X-ray absorptiometry (DXA), computed tomography (CT), magnetic resonance imaging (MRI), electromyography, quantitative muscle ultrasound, histological examination, and genetic analysis. Continuous monitoring of patients receiving glucocorticoid therapy plays an important role in enabling early detection of glucocorticoid-induced myopathy, allowing physicians to modify treatment plans before significant clinical weakness arises.

Development and validation of new bioelectrical impedance equations to accurately estimate fat mass percentage in a heterogeneous Caucasian population

Fat mass percentage (%FM) is frequently determined by nutritionists and personal trainers with bioelectrical impedance analysis (BIA) devices. The aims of the present study were: (1) to develop new regression equations using dual-energy X-ray absorptiometry (DXA) as the reference method for estimating %FM in a heterogeneous Caucasian population with a foot-to-hand device (BIA-101) and a hand-to-hand device (BIA-TELELAB) and (2) to compare the new equations with the manufacturers' equations. We hypothesized that the new equations would lead to more accurate estimations compared with DXA. A total of 218 healthy Caucasian participants aged 18 to 65 years were divided into a development group and a validation group. The accuracy of the different equations was assessed by mean differences, coefficient of determination, standard error of the estimate (SEE), intraclass correlation coefficients (ICC), and Bland-Altman plots. The proposed equation for BIA-101 explained 90.0% of the variance in the DXA-derived %FM, with a low random error (SEE = 2.98%), excellent agreement (ICC = 0.94), no fixed bias, and relatively low individual variability (5.86%). For BIA-TELELAB, the proposed equation explained 88.0% of the variance in the DXA-derived %FM, with a low random error (SEE = 3.27%), excellent agreement (ICC = 0.93), no fixed bias, and relatively low individual variability (6.37%). The results obtained for the manufacturers' equations confirm that these equations are not a good option for %FM assessment. As hypothesized, the new regression equations for BIA-101 and BIA-TELELAB devices can accurately estimate %FM in a heterogeneous Caucasian population with a broad age range.

Relationship between body composition and pulmonary function in the general population-a cross-sectional study in Ningxia

Studies considering the relationship between non-obesity-related body composition and lung function are few; therefore, this study aimed to explore these correlations and effects. This cross-sectional study conducted in rural Qingtongxia City and Pingluo County, Ningxia, China, included 776 participants aged 30-75 years. Body composition and lung function were measured using direct segmental multifrequency bioelectrical impedance analysis and a digital spirometer, respectively. Their correlation was assessed using partial correlation analysis, controlling for age and smoking status, and the body composition effect on lung function was analyzed using binomial logistic regression analysis. The body components total body water content, protein content, mineral content, muscle mass, fat-free mass (FFM), skeletal muscle mass, basal metabolic volume, and chest circumference (CC) positively correlated with pulmonary function (forced vital capacity and forced expiratory volume in one second) in both sexes. Neck circumference and hip circumference positively correlated with pulmonary function in women. Additionally, lung function declines more slowly in women (odds ratio [OR] = 0.66, 95% confidence interval [CI] = 0.44-0.98, p =  0.04); CC (OR = 0.92, 95% CI = 0.86-0.98, p = 0.01) increased as a protective factor for decreased lung function. Increased waist circumference (OR = 1.04, 95% CI = 1.00-1.09, p = 0.04) was a risk factor for reduced lung function. FFM contains body composition indicators positively correlating with lung function, excluding fat-related body composition. Abdominal obesity increases the risk of decreased lung function.

Bioimpedance and Duration of Organ Dysfunction in Septic Shock-A Prospective Observational Study

Rationale: Bioimpedance may be a useful tool to guide fluid treatment and avoid organ dysfunction related to fluid overload. Objective: We examined the correlation between bioimpedance and organ dysfunction in patients with septic shock. Methods: Prospective observational study of adult intensive care unit patients fulfilling the sepsis-3 criteria. Bioimpedance was measured using a body composition monitor (BCM) and BioScan Touch i8 (MBS). We measured impedance at inclusion and after 24 h and reported the impedance, change in impedance, bioimpedance-derived fluid balance, and changes in bioimpedance-derived fluid balance. Organ markers on respiratory, circulatory, and kidney function and overall disease severity were ascertained on days 1-7. The effect of bioimpedance on the change in organ function was assessed by mixed effects linear models. We considered P < .01 as significant. Measurements and Main Results: Forty-nine patients were included. None of the single baseline measurements or derived fluid balances were associated with the course of organ dysfunction. Changes in impedance were associated with the course of overall disease severity (P < .001; with MBS), and with changes in noradrenaline dose (P < .001; with MBS) and fluid balance (P < .001; with BCM). The changes in bioimpedance-derived fluid balance were associated with changes in noradrenaline dose (P < .001; with BCM), cumulative fluid balances (P < .001; with MBS), and lactate concentrations (P < .001; with BCM). Conclusions: Changes in bioimpedance were correlated with the duration of overall organ failure, circulatory failure, and fluid status. Single measurements of bioimpedance were not associated with any changes in organ dysfunction.

Systematic measuring cortical thickness in tibiae for bio-mechanical analysis

BACKGROUND AND OBJECTIVE

Measuring the thickness of cortical bone tissue helps diagnose bone diseases or monitor the progress of different treatments. This type of measurement can be performed visually from CAT images by a radiologist or by semi-automatic algorithms from Hounsfield values. This article proposes a mechanism capable of measuring thickness over the entire bone surface, aligning and orienting all the images in the same direction to have comparable references and reduce human intervention to a minimum. The objective is to batch process large numbers of patients' CAT images obtaining thicknesses profiles of their cortical tissue to be used in many applications.

METHODS

Classical morphological and Deep Learning segmentation is used to extract the area of interest, filtering and interpolation to clean the bones and contour detection and Signed Distance Functions to measure the cortical Thickness. The alignment of the set of bones is achieved by detecting their longitudinal direction, and the orientation is performed by computing their principal component of the center of mass slice.

RESULTS

The method processed in an unattended manner 67% of the patients in the first run and 100% in the second run. The difference in the thickness values between the values provided by the algorithm and the measures done by a radiologist was, on average, 0.25 millimetres with a standard deviation of 0.2.

CONCLUSION

Measuring the cortical thickness of a bone would allow us to prepare accurate traumatological surgeries or study their structural properties. Obtaining thickness profiles of an extensive set of patients opens the way for numerous studies to be carried out to find patterns between bone thickness and the patients' medical, social or demographic variables.

Low-cost chest paediatric phantom for dose optimisation: construction and validation

INTRODUCTION AND OBJECTIVES

In order to perform chest dose optimisation studies, the imaging phantom should be adequate for image quality evaluation. Since high-end phantoms are cost prohibitive, there is a need for a low-cost construction method with fairly available tissue substitutes.

MATERIALS AND METHODS

Theoretical calculations of radiological characteristics were performed for each of lung, cortical bone and soft tissues in order to choose appropriate substitute, then, cork, P.V.C. (Polyvinyl chloride) and water were chosen, respectively. Validation included, firstly, measuring CT Hounsfield Units (HU) of a real patient's tissues then compared against their corresponding anatomies in the constructed phantom. Secondly, Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) values were acquired in this study to evaluate the quality of images generated from the constructed phantom, then, compare their trends with a valid phantom under different exposure parameters (kVp and mAs).

RESULTS

From theoretical calculations, the percentage differences showed high accuracy of tissue substitutes when simulating real patient tissues; P.V.C. was ≥5.78%, cork was ≥4.46% and water ≥5%. The percentage difference (CT HU) between lung and cortical bone and their equivalent tissue substitutes were 10.44% and 0.53%-3.17%, respectively. Strong positive correlations were found for SNR when changing both kVp (0.79) and mAs (0.65). While the correlation strength of CNR values were found to be moderate when changing both kVp (0.58) and mAs (0.53).

CONCLUSIONS

Our low-cost phantom approved through CT HU that their materials replicate the radiological characteristics of real one-year-old child while SNR and SNR correlations confirmed its applicability in imaging and optimisation studies.

Bioimpedance as a measure of fluids in patients with septic shock. A prospective observational study

BACKGROUND

Septic shock is often treated with aggressive fluid resuscitation leading to profound fluid overload. The assessment of fluid status relies on suboptimal measures making treatment difficult. Bioelectrical impedance analysis is an alternative but the validity is unclear. The aim of this study was to determine the validity of bioelectrical impedance analysis for fluid measures in patients with septic shock.

METHODS

Single-center, prospective observational cohort study. We included adult ICU patients with septic shock. We evaluated the agreement between measures on the left and right side of the patient and measures 1 h apart by two bioelectrical impedance devices. Results are presented as Bland Altman plots with 95% Limits of Agreements (LoA) and as correlations between bioelectrical impedance analysis results and clinical markers of fluids.

RESULTS

Forty-nine patients were included. The agreement between measures on the left and the right side of the patient and after 1 h was overall without bias, but with wide LoA's. Fluid overload 1 h apart showed the most narrow 95% LoA (-2.4-2.9 L). The same wide limits of agreements were observed when comparing devices. For example, total body water with 95% LoA of -14.8 -16.7 L. Correlations between bioelectrical impedance analysis and clinical measures were low but statistically significant.

CONCLUSIONS

In patients with septic shock bioelectrical impedance analysis had no systematic errors or bias, but wide limits of agreement, indicating that the devices have a large and uncorrectable random error. Fluid status by bioelectrical impedance analysis is not sufficiently accurate to guide treatment in this group of patients.

Phase angle (PhA) in overweight and obesity: evidence of applicability from diagnosis to weight changes in obesity treatment

Phase angle (PhA) is a recently proposed marker of nutritional status in many clinical conditions. Its use in patients with obesity presents different critical concerns due to the higher variability of the two measured parameters (resistance, R, and reactance, Xc) that contribute to the determination of PhA. Controversial is the relation between PhA and BMI that might vary with graded levels of obesity due to the variation in fat and free fat mass. Obesity is frequently associated with metabolic, hepatic, cardiovascular and kidney diseases that introduce variations in PhA values, in relation to multimorbidity and severity degree of these diseases. It is reported that the improvement of clinical condition is associated with a positive change in PhA. Also, the treatment of obesity with weight loss might confirm this effect, but with different responses in relation to the type and duration of the intervention applied. In fact, the effect appears not only related to the percentage of weight loss but also the possible loss of free fat mass and the nutritional, metabolic and structural modifications that might follow each therapeutic approach to decrease body weight. We can conclude that the PhA could be used as marker of health status in patients with obesity supporting an appropriate weight loss intervention to monitor efficacy and fat free mass preservation.

Field-based adipose tissue quantification in sea turtles using bioelectrical impedance spectroscopy validated with CT scans and deep learning

Loss of adipose tissue in vertebrate wildlife species is indicative of decreased nutritional and health status and is linked to environmental stress and diseases. Body condition indices (BCI) are commonly used in ecological studies to estimate adipose tissue mass across wildlife populations. However, these indices have poor predictive power, which poses the need for quantitative methods for improved population assessments. Here, we calibrate bioelectrical impedance spectroscopy (BIS) as an alternative approach for assessing the nutritional status of vertebrate wildlife in ecological studies. BIS is a portable technology that can estimate body composition from measurements of body impedance and is widely used in humans. BIS is a predictive technique that requires calibration using a reference body composition method. Using sea turtles as model organisms, we propose a calibration protocol using computed tomography (CT) scans, with the prediction equation being: adipose tissue mass (kg) = body mass - (-0.03 [intercept] - 0.29 * length2/resistance at 50 kHz + 1.07 * body mass - 0.11 * time after capture). CT imaging allows for the quantification of body fat. However, processing the images manually is prohibitive due to the extensive time requirement. Using a form of artificial intelligence (AI), we trained a computer model to identify and quantify nonadipose tissue from the CT images, and adipose tissue was determined by the difference in body mass. This process enabled estimating adipose tissue mass from bioelectrical impedance measurements. The predictive performance of the model was built on 2/3 samples and tested against 1/3 samples. Prediction of adipose tissue percentage had greater accuracy when including impedance parameters (mean bias = 0.11%-0.61%) as predictor variables, compared with using body mass alone (mean bias = 6.35%). Our standardized BIS protocol improves on conventional body composition assessment methods (e.g., BCI) by quantifying adipose tissue mass. The protocol can be applied to other species for the validation of BIS and to provide robust information on the nutritional and health status of wildlife, which, in turn, can be used to inform conservation decisions at the management level.

Official position of the Brazilian Association of Bone Assessment and Metabolism (ABRASSO) on the evaluation of body composition by densitometry: part I (technical aspects)—general concepts, indications, acquisition, and analysis

Objective

To review the technical aspects of body composition assessment by dual-energy X-ray absorptiometry (DXA) and other methods based on the most recent scientific evidence.

Materials and methods

This Official Position is a result of efforts by the Scientific Committee of the Brazilian Association of Bone Assessment and Metabolism (Associação Brasileira de Avaliação Óssea e Osteometabolismo, ABRASSO) and health care professionals with expertise in body composition assessment who were invited to contribute to the preparation of this document. The authors searched current databases for relevant publications. In this first part of the Official Position, the authors discuss the different methods and parameters used for body composition assessment, general principles of DXA, and aspects of the acquisition and analysis of DXA scans.

Conclusion

Considering aspects of accuracy, precision, cost, duration, and ability to evaluate all three compartments, DXA is considered the gold-standard method for body composition assessment, particularly for the evaluation of fat mass. In order to ensure reliable, adequate, and reproducible DXA reports, great attention is required regarding quality control procedures, preparation, removal of external artifacts, imaging acquisition, and data analysis and interpretation.

A review on the Role of Oral Nutritional Supplements in Chronic Obstructive Pulmonary Disease

Due to the high smoking rate in developing countries and the rising aging population in high-income countries, the global prevalence of chronic obstructive pulmonary disease (COPD), estimated to be 11.7%, is increasing and is the third-leading cause of mortality. COPD is likely to be present in elderly individuals with impaired gastro-enteric functions. Gastrointestinal congestion, dyspnea, and anxiety are pathophysiological characteristics of COPD, contributing to poor appetite, reduced dietary intake, and high-energy expenditure. These factors are implicated in the progression of malnutrition in COPD patients. Malnutrition is detrimental to lung functions and is associated with an increased risk of infection, exacerbation and mortality, and a longer duration of hospitalization. Therefore, nutritional support to treat malnutrition in COPD patients is very vital. Oral nutritional supplements (ONS) may hold the key to COPD treatment. To clarify this statement, we review current evidence for ONS in COPD patients to benefit from clinical outcomes.

Bioimpedance as a measure of fluid status in critically ill patients: A systematic review

OBJECTIVE

Precise measurements of fluid status lack valid methods. Bioimpedance is an attractive diagnostic tool because it is noninvasive, quick, and relatively cheap. This systematic review aims to assess the existing evidence of bioimpedance as an accurate measure of fluid status in critically ill patients.

DATA SOURCES

PubMed and Embase up till March 2021 were systematically searched (PROSPERO: CRD42020157436).

STUDY SELECTION

Eligibility criteria were studies reporting original data from cohorts of adult patients in intensive care units and doing at least one whole-body bioimpedance and one reference test. In addition, studies assessing internal reproducibility were included.

DATA EXTRACTION

An extraction form was designed for the purpose.

DATA SYNTHESIS

Nine hundred five studies were screened for eligibility, and 28 studies, comprising 1482 individual patients, were included in the final analysis. Eight studies compared bioimpedance with a gold standard, and two of those reported the results adequate. We found a low mean difference, but the 95% limits of agreements had wide limits. The remaining studies applied different surrogates as reference tests. Correlations ranged from 0.05 to 0.99. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) certainty of evidence for all outcomes was very low.

CONCLUSIONS

The accuracy of bioimpedance as a measure for fluids in critically ill patients in the intensive care unit cannot be determined. Due to the lack of a gold standard, numerous studies compared bioimpedance with surrogate outcomes with great variability in both designs and results. Assessing the internal reproducibility of bioimpedance had the same limitations, but the studies overall reported good internal reproducibility.

The product of trunk muscle area and density on the CT image is a good indicator of energy expenditure in patients with or at risk for COPD

BACKGROUND

Physical inactivity due to cachexia and muscle wasting is well recognized as a sign of poor prognosis in chronic obstructive pulmonary disease (COPD). However, there have been no reports on the relationship between trunk muscle measurements and energy expenditure parameters, such as the total energy expenditure (TEE) and physical activity level (PAL), in COPD. In this study, we investigated the associations of computed tomography (CT)-derived muscle area and density measurements with clinical parameters, including TEE and PAL, in patients with or at risk for COPD, and examined whether these muscle measurements serve as an indicator of TEE and PAL.

METHODS

The study population consisted of 36 male patients with (n = 28, stage 1-4) and at risk for (n = 8) COPD aged over 50 years. TEE was measured by the doubly labeled water method, and PAL was calculated as the TEE/basal metabolic rate estimated by the indirect method. The cross-sectional areas and densities of the pectoralis muscles, rectus abdominis muscles, and erector spinae muscles were measured. We evaluated the relationship between these muscle measurements and clinical outcomes, including body composition, lung function, muscle strength, TEE, and PAL.

RESULTS

All the muscle areas were significantly associated with TEE, severity of emphysema, and body composition indices such as body mass index, fat-free mass, and trunk muscle mass. All trunk muscle densities were correlated with PAL. The product of the rectus abdominis muscle area and density showed the highest association with TEE (r = 0.732) and PAL (r = 0.578). Several trunk muscle measurements showed significant correlations with maximal inspiratory and expiratory pressures, indicating their roles in respiration.

CONCLUSIONS

CT-derived measurements for trunk muscles are helpful in evaluating physical status and function in patients with or at risk for COPD. Particularly, trunk muscle evaluation may be a useful marker reflecting TEE and PAL.

Relationship between Biological Maturation, Physical Fitness, and Kinanthropometric Variables of Young Athletes: A Systematic Review and Meta-Analysis

There is a growing interest in knowing the relationship between biological maturation and sport performance-related variables of young athletes. The objective of this study is to analyze the relationship between biological maturation, physical fitness, and kinanthropometric variables of athletes during their growing period, according to their sex. The systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement and the search protocol was registered in PROSPERO, code: CRD42020208397. A search through the PubMed, Web of Sciences, and EBSCO databases was performed. A total of 423 studies were screened and 13 were included in the meta-analysis. The meta-analysis was completed by using the mean and standard deviation of each variable according to each maturation status (early, on time, or late). Differences depending on maturation were found on physical fitness, with better results in the advanced maturational groups in the male population (standard mean difference (SMD) = 0.17-2.31; p < 0.001-0.05). Differences depending on maturation were found for kinanthropometric variables in males (SMD = 0.37-2.31; p < 0.001-0.002) and height and body mass in females (SMD = 0.96-1.19; p < 0.001). In conclusion, the early maturation group showed higher values in kinanthropometric variables and better results in physical fitness, highlighting the importance of the maturational process in the talent selection programs. Despite that, more research is needed to clarify the relationship of maturation with the other variables on female populations and the changes in the muscle and bone variables during the maturation processes of both sexes.

Sarcopenia, Diet, Physical Activity and Obesity in European Middle-Aged and Older Adults: The LifeAge Study

The revised European consensus defined sarcopenia as a progressive and generalized skeletal muscle disorder that is associated with an increased likelihood of adverse outcomes including falls, fractures, physical disability and mortality. The aim of this study was to determine the prevalence of sarcopenia and analyse the influence of diet, physical activity (PA) and obesity index as risk factors of each criteria of sarcopenia. A total of 629 European middle-aged and older adults were enrolled in this cross-sectional study. Anthropometrics were assessed. Self-reported PA and adherence to the Mediterranean diet were evaluated with the Global Physical Activity Questionnaire (GPAQ) and Prevention with Mediterranean Diet questionnaire (PREDIMED), respectively. The functional assessment included handgrip strength, lower body muscle strength, gait speed and agility/dynamic balance. Of the participants, 4.84% to 7.33% showed probable sarcopenia. Sarcopenia was confirmed in 1.16% to 2.93% of participants. Severe sarcopenia was shown by 0.86% to 1.49% of participants. Male; age group ≤65 years; lower body mass index (BMI); high levels of vigorous PA; and the consumption of more than one portion per day of red meat, hamburgers, sausages or cold cuts and/or preferential consumption of rabbit, chicken or turkey instead of beef, pork, hamburgers or sausages (OR = 0.126-0.454; all p < 0.013) resulted as protective factors, and more time of sedentary time (OR = 1.608-2.368; p = 0.032-0.041) resulted as a risk factor for some criteria of sarcopenia. In conclusion, age, diet, PA, and obesity can affect the risk of having low muscle strength, low muscle mass or low functional performance, factors connected with sarcopenia.

Differences in Fat Mass Estimation Formulas in Physically Active Adult Population and Relationship with Sums of Skinfolds

Changes in body composition and specifically fat mass, has traditionally been used as a way to monitor the changes produced by nutrition and training. The objective of the present study was to analyse the differences between the formulas used to estimate fat mass and to establish the existing relationship with the body mass index and sums of skinfolds measurement in kinanthropometry. A total of 2458 active adults participated in the study. Body mass index (BMI) and skinfolds were measured, and the Kerr, Durnin-Womersley, Faulkner and Carter equations were used to assess fat mass. Significant differences were found between all the formulas for the percentage of fat mass, ranging from 10.70 ± 2.48 to 28.43 ± 5.99% (p < 0.001) and fat mass from 7.56 ± 2.13 to 19.89 ± 4.24 kg (p < 0.001). The correlations among sums of skinfolds and the different equations were positive, high and significant in all the cases (r from 0.705 to 0.926 p < 0.001), unlike in the case of BMI, were the correlation was lower and both positive or negative (r from -0.271 to 0.719; p < 0.001). In conclusion, there were differences between all the formulas used to estimate fat mass; thus, for the evaluation of fat mass with kinanthropometry of an active adult, the use of the same formula is recommended on all occasions when the results are going to be compared or when an athlete is compared with a reference.

Skeletal Muscle Aging Atrophy: Assessment and Exercise-Based Treatment

In the ordinary course of aging, individuals change their body composition, mainly reducing their skeletal muscle mass and increasing their fat mass. In association, muscle strength and functionality also decrease. The geriatric assessment allows knowing the baseline situation of the patients, determines the impact of diseases, and defines specific treatments. There are various tools to evaluate the health condition of older people. These tools include the assessment scales of necessary Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL), physical and functional assessment scales, and instruments that assess the cognitive state of the person. There are several strategies that have been proposed to combat skeletal muscle atrophy due to aging, such as physical exercise, nutritional supplements, or drugs. Some researchers have highlighted the efficacy of the combination of the mentioned strategies. In this chapter, we will focus only on physical exercise as a strategy to reduce skeletal muscle loss during aging.

Development and validation of a bespoke phantom to test accuracy of Cobb angle measurements

INTRODUCTION

Adolescent idiopathic scoliosis (AIS) is a spinal deformity that causes the spine to bend laterally. Patients with AIS undergo frequent X-ray examinations to monitor the progression of the disorder by through the measurement of the Cobb angle. Frequent exposure of adolescents poses the risk of radiation-induced cancer. The aim of this research was to design and build a bespoke phantom representing a 10-year-old child with AIS to allow optimisation of imaging protocols for AIS assessment through the accuracy of Cobb angle measurements.

METHODS

Poly-methyl methacrylate (PMMA) and plaster of Paris (PoP) were used to represent human soft tissue and bone tissue, respectively, to construct a phantom exhibiting a 15° lateral curve of the spine. The phantom was validated by comparing the Hounsfield unit (HU) of its vertebrae with that of human and sheep. Additionally, comparisons of signal-to-noise ratio (SNR) to those from a commercially available phantom. An assessment of the accuracy of the radiographic assessment of the Cobb angle measurement was performed.

RESULTS

The HU of the PoP vertebrae was 628 (SD = 56), human vertebrae was 598 (SD = 79) and sheep vertebra was 605 (SD = 83). The SNR values of the two phantoms correlated strongly (r = 0.93 (p = 0.00)). The measured scoliosis angle was 14°.

CONCLUSION

The phantom has physical characteristics (in terms of spinal deformity) and radiological characteristics (in terms of HU and SNR values) of the spine of a 10-year-old child with AIS. This phantom has utility for the optimisation of x-ray imaging techniques in 10 year old children.

IMPLICATIONS FOR PRACTICE

A phantom to investigate new x-ray imaging techniques and technology in the assessment of scoliosis and to optimise currently used protocols.

Clinical Value of Muscle Mass Assessment in Clinical Conditions Associated with Malnutrition

Malnutrition results from a reduction of food intake or an alteration of nutrient assimilation and leads to decreased lean mass. Strong evidence shows that malnutrition associated with loss of muscle mass negatively impacts clinical outcomes. The preservation or improvement of muscle mass represents a challenge. This review aims to (1) describe current methods to assess muscle mass in clinical practice, (2) describe the associations between muscle mass and clinical outcomes, and (3) describe the impact of interventions aiming at increasing muscle mass on clinical outcomes. It highlights the importance of assessing muscle mass as part of the screening and the follow-up of malnutrition in clinical practice.

Quantification of body-torso-wide tissue composition on low-dose CT images via automatic anatomy recognition

PURPOSE

Quantification of body composition plays an important role in many clinical and research applications. Radiologic imaging techniques such as Dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), and computed tomography (CT) imaging make accurate quantification of the body composition possible. However, most current imaging-based methods need human interaction to quantify multiple tissues. When dealing with whole-body images of many subjects, interactive methods become impractical. This paper presents an automated, efficient, accurate, and practical body composition quantification method for low-dose CT images.

METHOD

Our method, named automatic anatomy recognition body composition analysis (AAR-BCA), aims to quantify four tissue components in body torso (BT) - subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), bone tissue, and muscle tissue - from CT images of given whole-body positron emission tomography/computed tomography (PET/CT) acquisitions. AAR-BCA consists of three key steps - modeling BT with its ensemble of key objects from a population of patient images, recognition or localization of these objects in a given patient image I, and delineation and quantification of the four tissue components in I guided by the recognized objects. In the first step, from a given set of patient images and the associated delineated objects, a fuzzy anatomy model of the key object ensemble, including anatomic organs, tissue regions, and tissue interfaces, is built where the objects are organized in a hierarchical order. The second step involves recognizing, or finding roughly the location of, each object in any given whole-body image I of a patient following the object hierarchy and guided by the built model. The third step makes use of this fuzzy localization information of the objects and the intensity distributions of the four tissue components, already learned and encoded in the model, to optimally delineate in a fuzzy manner and quantify these components. All parameters in our method are determined from training datasets.

RESULTS

Thirty-eight low-dose CT images from different subjects are tested in a fivefold cross-validation strategy for evaluating AAR-BCA with a 23-15 train-test dataset division. For BT, over all objects, AAR-BCA achieves a false-positive volume fraction (FPVF) of 3.7% and false-negative volume fraction (FNVF) of 3.8%. Notably, SAT achieves both a FPVF and FNVF under 3%. For bone tissue, it achieves a FPVF and a FNVF both under 3.5%. For VAT tissue, the FNVF of 4.8% is higher than for other objects and so also for muscle (4.7%). The level of accuracy for the four tissue components in individual body subregions mostly remains at the same level as for BT. The processing time required per patient image is under a minute.

CONCLUSIONS

Motivated by applications in cancer and systemic diseases, our goal in this paper was to seek a practical method for body composition quantification which is automated, accurate, and efficient, and works on BT in low-dose CT. The proposed AAR-BCA method toward this goal can quantify four tissue components including SAT, VAT, bone tissue, and muscle tissue in the body torso with under 5% overall error. All needed parameters can be automatically estimated from the training datasets.

Abdominal volume computed tomography assessment of body composition in dogs

Background

Computed tomography (CT) has been used to estimate body composition and determine tissue distribution in dogs, despite limited validation. This may introduce error into estimates of body composition studies and its effect on health in dogs. Further, the modality has not been validated against dual-energy X-ray absorptiometry (DXA) or over a wide range of dog breeds, ages and sexes. The objective of this study was to validate the use of semi-automated, abdominal volume CT for estimating total body composition of dogs relative to DXA. Twenty-two staff-owned dogs (weighing between 5.1-60 kg) were sedated and underwent full body DXA scan and abdominal CT. Abdominal tissue composition was estimated by CT using semi-automated volume segmentation, over predetermined tissue Hounsfield threshold values. Abdominal tissue composition determined by the various CT threshold ranges was compared to total body composition determined by DXA.

Results

Abdominal tissue composition estimated by CT strongly correlated with the estimates derived from DXA with a small Bland-Altman mean percentage differences in values: total body mass (− 250/2000HU: r² = 0.985; − 1.10%); total fat mass (− 250/-25HU: r² = 0.981; − 1.90%); total lean tissue mass (− 25/150HU: r² = 0.972; 3.47%); and total bone mineral content (150/2000HU: r² = 0.900; − 0.87%). Although averaged CT values compared well to DXA analysis, there was moderate variation in the individual predicted values. There was near perfect inter- and intra-observer agreement in segmentation volumes for abdominal fat.

Conclusions

Abdominal volume computed tomography (CT) accurately and reliably estimates total body composition in dogs, but greater variations may be observed in dogs weighing less than 10 kg.

Construction and validation of a low cost paediatric pelvis phantom

PURPOSE

Imaging phantoms can be cost prohibitive, therefore a need exists to produce low cost alternatives which are fit for purpose. This paper describes the development and validation of a low cost paediatric pelvis phantom based on the anatomy of a 5-year-old child.

METHODS

Tissue equivalent materials representing paediatric bone (Plaster of Paris; PoP) and soft tissue (Poly methyl methacrylate; PMMA) were used. PMMA was machined to match the bony anatomy identified from a CT scan of a 5-year-old child and cavities were created for infusing the PoP. Phantom validation comprised physical and visual measures. Physical included CT density comparison between a CT scan of a 5-year old child and the phantom and Signal to Noise Ratio (SNR) comparative analysis of anteroposterior phantom X-ray images against a commercial anthropomorphic phantom. Visual analysis using a psychometric image quality scale (face validity).

RESULTS

CT density, the percentage difference between cortical bone, soft tissue and their equivalent tissue substitutes were -4.7 to -4.1% and -23.4%, respectively. For SNR, (mAs response) there was a strong positive correlation between the two phantoms (r > 0.95 for all kVps). For kVp response, there was a strong positive correlation between 1 and 8 mAs (r = 0.85), this then decreased as mAs increased (r = -0.21 at 20 mAs). Psychometric scale results produced a Cronbach's Alpha of almost 0.8.

CONCLUSIONS

Physical and visual measures suggest our low-cost phantom has suitable anatomical characteristics for X-ray imaging. Our phantom could have utility in dose and image quality optimisation studies.

Can anthropometric, body composition, and bone variables be considered risk factors for musculoskeletal injuries in Brazilian military students?

Background

Musculoskeletal injuries are the main cause of premature discharge from military service and can sometimes lead to permanent disabilities. Some intrinsic risk factors are well discussed in the literature. However, the relation between body composition variables and the risk for musculoskeletal injury is not well known or recognized.

Methods

This prospective study evaluated 205 Brazilian military students. At the beginning of military service, health status and sports experience prior to military service were registered. Anthropometric variables were evaluated, and bone and body composition variables were measured using dual-energy X-ray absorptiometry. The occurrence of musculoskeletal injuries throughout the year was registered at the military physiotherapy service. At the end of 1 year of follow-up, risk factors were analysed by comparing the variables between the injured and non-injured students.

Results

No difference in previous health status was found between injured and non-injured groups, whereas sports experience prior to military service was identified as a protective factor (Odds Ratio (OR) 0.323; 95% CI: 0.108–0.968; p = 0.044). Anthropometric, bone, and body composition variables could not be identified as risk factors for musculoskeletal injuries in Brazilian military students.

Conclusion

Anthropometric, bone, and body composition variables could not be considered risk factors for musculoskeletal injuries in Brazilian military students.

Preliminary research on body composition measurement using X-ray phase contrast imaging

Body composition measurement is of cardinal significance for medical and clinical applications. Currently, the dual-energy X-ray absorptiometry (DEXA) technique is widely applied for this measurement. In this study, we present a novel measurement method using the absorption and phase information obtained simultaneously from the X-ray grating-based interferometer (XGI). Rather than requiring two projection data sets with different X-ray energy spectra, with the proposed method, both the areal densities of the bone and the surrounding soft tissue can be acquired utilizing one projection data set. By using a human body phantom constructed to validate the proposed method, experimental results have shown that the compositions can be calculated with an improved accuracy comparing to the dual energy method, especially for the soft tissue measurement. Since the proposed method can be easily implemented on current XGI setup, it will greatly extend the applications of the XGI, and meanwhile has the potential to be an alternative to DEXA for human body composition measurement.

Oral Supplementation with Beta-Hydroxy-Beta-Methylbutyrate, Arginine, and Glutamine Improves Lean Body Mass in Healthy Older Adults

Oral intake of beta-hydroxy-beta-methylbutyrate (HMB), arginine, and glutamine may ameliorate muscle loss by stimulating protein synthesis and decreasing protein degradation while simultaneously decreasing inflammation. Previous studies provide evidence for improvement in body composition with dietary supplementation of these ingredients among patients with muscle-wasting diseases. The objectives of this study were to examine the effects of this amino acid mixture on lean body mass, muscle volume, and physical function among healthy older adults. Thirty-one community-dwelling men and women, aged 65-89 years, were randomized to either two oral doses of the amino acid supplement (totaling 3 g HMB, 14 g arginine, 14 g glutamine) or placebo daily for six months. At baseline and month six, lean body mass was measured by air displacement plethysmography, dual-energy X-ray absorptiometry (DXA), and four-compartment model. Muscle volume of quadriceps was quantified by magnetic resonance imaging (MRI), and participants performed a battery of tests to assess physical function. As compared to the placebo group, the treatment group exhibited improvement in a timed stair climb (p =.016) as well as significant increases in lean body mass by all methods of assessment (p <.05). Regional analysis by DXA revealed increased arm lean mass in the supplement group only (p =.035). However, no change was observed in MRI-derived quadriceps volume. Dietary supplementation with HMB, arginine, and glutamine improved total body lean mass among a small sample of healthy older adults. Further research is indicated to elucidate mechanisms of action and to determine whether supplementation may benefit frail elders. Registered under ClinicalTrials.gov identifier no. NCT01057082.

Fully automated segmentation and quantification of visceral and subcutaneous fat at abdominal CT: application to a longitudinal adult screening cohort

OBJECTIVE

To investigate a fully automated CT-based adiposity tool, applying it to a longitudinal adult screening cohort.

METHODS

A validated automated adipose tissue segmentation algorithm was applied to non-contrast abdominal CT scans in 8852 consecutive asymptomatic adults (mean age, 57.1 years; 3926 M/4926 F) undergoing colonography screening. The tool was also applied to follow-up CT scans in a subset of 1584 individuals undergoing longitudinal surveillance (mean interval, 5.6 years). Visceral and subcutaneous adipose tissue (VAT and SAT) volumes were segmented at levels T12-L5. Primary adipose results are reported herein for the L1 level as mean cross-sectional area. CT-based adipose measurements at initial CT and change over time were analyzed.

RESULTS

Mean VAT values were significantly higher in males (205.8 ± 107.5 vs 108.1 ± 82.4 cm²; p < 0.001), whereas mean SAT values were significantly higher in females (171.3 ± 111.3 vs 124.3 ± 79.7 cm²; p < 0.001). The VAT/SAT ratio at L1 was three times higher in males (1.8 ± 0.7 vs 0.6 ± 0.4; p < 0.001). At longitudinal follow-up CT, mean VAT/SAT ratio change was positive in males, but negative in females. Among the 502 individuals where the VAT/SAT ratio increased at follow-up CT, 333 (66.3%) were males. Half of patients (49.6%; 786/1585) showed an interval increase in both VAT and SAT at follow-up CT.

CONCLUSION

This robust, fully automated CT adiposity tool allows for both individualized and population-based assessment of visceral and subcutaneous abdominal fat. Such data could be automatically derived at abdominal CT regardless of the study indication, potentially allowing for opportunistic cardiovascular risk stratification. Advances in knowledge: The CT-based adiposity tool described herein allows for fully automated measurement of visceral and subcutaneous abdominal fat, which can be used for assessing cardiovascular risk, metabolic syndrome, and for change over time.

Does field hockey increase morphofunctional asymmetry? A pilot study

Common practice in field hockey requires athletes to adopt a semi-crouched posture, so players have a greater risk of musculoskeletal disorders than non-athletes. The aim of the present study was to assess how field hockey determines asymmetry in morphological and functional characteristics of the body by comparing athletes to control participants. The sample consisted of 15 male field hockey players from the Polish Youth National Team and 14 male university students. Antimeric differences in the chosen variables between body sub-regions were assessed. All morphological characteristics (bone mineral density, fat mass, and lean mass) were estimated using a dual energy X-ray absorptiometry. Additionally, the range of motion in transverse and frontal planes of the cervical, thoracic and lumbar spine was measured by using an electrogoniometric system. The results showed that the values of all morphological characteristics were higher in the left body segments, both in athletes and controls. However, the differences between sides were much more pronounced in the field hockey players. With regard to functional traits, higher values were obtained for the right body side in athletes but for the left side of the body among the controls. The difference between right and left side bending increased from the cervical spine (2.7%) through thoracic spine (7.8%) to lumbar spine (16.5%) in athletes. Rotational asymmetry in the thoracic spine was the largest in both groups. These findings indicate that it is important to monitor all athletes to prevent injury and health problems connected with strong morphological asymmetry.

Phase-contrast imaging for body composition measurement

PURPOSE

In this paper, we propose a novel method for human body composition measurement, especially for the bone mineral density (BMD) measurement. The proposed method, using the absorption and differential phase information retrieved from X-ray grating-based interferometer (XGBI) to measure the BMD, has potential to replace dual-energy X-ray absorptiometry (DEXA), which is currently widely used for body composition measurement.

METHODS

The DEXA method employs two absorption images acquired at two different X-ray spectra (high energy and low energy) to calculate the human body composition. In this paper, a new method to calculate BMD using a single X-ray measurement is proposed. XGBI is a relatively new X-ray technique that provides absorption, phase and scattering information simultaneously using a single X-ray spectrum. With the absorption and differential phase information retrieved from XGBI, BMD can be measured using only one single X-ray spectrum. Numerical simulations are performed with a body phantom of bone (Cortical, ICRU-44) surrounded by soft tissue (Soft, ICRU-44). BMD is calculated with both the DEXA method and the proposed method.

RESULTS

Results show that BMD can be measured accurately with the proposed method; moreover, better signal-to-noise ratio (SNR) is obtained compared to DEXA.

CONCLUSION

With the proposed method, BMD can be measured with XGBI setup. Further, the proposed method can be realized using current X-ray phase-contrast imaging (XPCI) apparatus without any hardware modification, suggesting that this technique can be a promising supplementary function to current XPCI equipment.

Evaluation of a semi-automated computer algorithm for measuring total fat and visceral fat content in lambs undergoing in vivo whole body computed tomography

Computed tomography (CT) is a suitable tool for measuring body fat, since it is non-destructive and can be used to differentiate metabolically active visceral fat from total body fat. Whole body analysis of body fat is likely to be more accurate than single CT slice estimates of body fat. The aim of this study was to assess the agreement between semi-automated computer analysis of whole body volumetric CT data and conventional proximate (chemical) analysis of body fat in lambs. Data were collected prospectively from 12 lambs that underwent duplicate whole body CT, followed by slaughter and carcass analysis by dissection and chemical analysis. Agreement between methods for quantification of total and visceral fat was assessed by Bland-Altman plot analysis. The repeatability of CT was assessed for these measures using the mean difference of duplicated measures. When compared to chemical analysis, CT systematically underestimated total and visceral fat contents by more than 10% of the mean fat weight. Therefore, carcass analysis and semi-automated CT computer measurements were not interchangeable for quantifying body fat content without the use of a correction factor. CT acquisition was repeatable, with a mean difference of repeated measures being close to zero. Therefore, uncorrected whole body CT might have an application for assessment of relative changes in fat content, especially in growing lambs.

Comparison of bioimpedance spectroscopy and X-Ray micro-computed tomography for total fat volume measurement in mice

Obesity and the metabolic syndrome are two pathologies whose prevalence are in a constant increase. Evaluation of the total fat mass but also of the distribution between visceral and subcutaneous adipose tissue are important factors while assessing the pathophysiology of these two pathologies. Computed tomography (CT) and bioimpedance (BIS) are the translational methods the most frequently used in human beings as well as in rodent models in longitudinal studies on adiposity and obesity. Surprisingly, no direct comparison of micro-CT and BIS was reported yet in mice. Therefore, the present study was carried out to evaluate and compare the accuracy and the uncertainty of measurement of micro-CT and BIS in this species. The proportion of fat mass was measured with BIS, micro-CT and direct post-mortem tissue weight, and correlations between the data were established to evaluate the accuracy of the methods but also the uncertainty of BIS and micro-CT. There were significant correlations between weights of fat tissues on scale and proportion of total fat mass determined by BIS or micro-CT (r = 0.81 and 0.86 respectively) but both methods overestimated the total fat mass, especially in the smallest animals; overestimation of fat mass was amplified with BIS compared to micro-CT. In addition BIS and micro-CT were highly correlated (r = 0.94). Test-test reliability showed a greater variability of the BIS with respect to the micro-CT (coefficient of variation = 17.2 vs 5.6% respectively). Hence, as far as subtle differences between groups or changes within one group are awaited, micro-CT may appear as the most reliable method for determination of fat mass in mice. Micro-CT, unlike BIS, will also allow to qualitatively and quantitatively differentiate between subcutaneous and visceral adipose tissues, which is of major importance in studies on adiposity and its complications.

Measurement of muscle mass in sarcopenia: from imaging to biochemical markers

Sarcopenia encompasses the loss of muscle mass and strength/function during aging. Several methods are available for the estimation of muscle or lean body mass. Popular assessment tools include body imaging techniques (e.g., magnetic resonance imaging, computed tomography, dual X-ray absorptiometry, ultrasonography), bioelectric impedance analysis, anthropometric parameters (e.g., calf circumference, mid-arm muscle circumference), and biochemical markers (total or partial body potassium, serum and urinary creatinine, deuterated creatine dilution method). The heterogeneity of the populations to be evaluated as well as the setting in which sarcopenia is investigated impacts the definition of "gold standard" assessment techniques. The aim of this article is to critically review available methods for muscle mass estimation, highlighting strengths and weaknesses of each of them as well as their proposed field of application.

Sleep Quality and Body Composition Variations in Obese Male Adults after 14 Weeks of Yoga Intervention: A Randomized Controlled Trial

Background:

Obesity is a big challenge all over the world. It is associated with many noncommunicable diseases. Yoga known to be add-on treatment may be effective for obesity control.

Aim:

To assess the effect of integrated approach of yoga therapy (IAYT) for body composition and quality of sleep in adult obese male.

Subjects and Methods:

A randomized controlled trial was conducted for 14 weeks on obese male of urban setting. Eighty individuals were randomly divided into two groups, i.e., yoga group (n = 40; age; 40.03 ± 8.74 years, body mass index [BMI] 28.7 ± 2.35 kg/m²) and control group (age; 42.20 ± 12.06 years, BMI 27.70 ± 2.05 kg/m²). The IAYT was imparted to yoga group for 1½ hour for 5 days in a week for 14 weeks. The control group continued their regular activities. The body composition by InBody R20 and sleep quality by Pittsburgh Sleep Quality Index (PSQI) were assessed. Statistical analysis was done for within and between groups using SPSS version 21. The correlation analysis was done on the difference in pre-post values.

Results:

The results showed that weight (P = 0.004), BMI (P = 0.008), bone mass (P = 0.017), obesity degree (P = 0.005), and mineral mass (P = 0.046) were improved in yoga group and no change in control group (P > 0.05). The global score of PSQI improved (P = 0.017) in yoga group alone.

Conclusion:

The results indicate the beneficial effects of IAYT on body composition and sleep quality in obese males. The yoga practice may reduce obesity with the improvement in quality of life.

COMPREHENSIVE RADIATION DOSE MEASUREMENTS AND MONTE CARLO SIMULATION FOR THE 7Li(p,n) ACCELERATOR NEUTRON FIELD

In order to investigate the radiation dose dependence on the incident proton energy, neutron and gamma-ray doses were measured using a tissue-equivalent proportional counter in the proton energy range of 1.95-2.50 MeV for the McMaster ⁷Li(p,n) neutron facility. Microdosimetric spectra were collected, and absorbed doses were determined at various positions inside the irradiation cavity, along the lateral axis and outside the shield to find out the spatial distributions of neutron and gamma-ray doses for each proton energy. In parallel with the absorbed dose measurements, MCNP Monte Carlo simulations were carried out and neutron fluence spectra were computed at various positions, which enabled determination of the neutron weighting factors. It was found that neutrons make a substantially dominant contribution to the total equivalent dose for most proton energies and positions. The effective dose for a human subject increased from 0.058 to 1.306 μSv μA^-1 min^-1 with the increase of proton energy from 1.95 to 2.5 MeV. It is expected that the reported data will be useful for ⁷Li(p,n) accelerator neutron users.

Fatness of female field hockey players: Comparison of estimates with different methods

The aim of the study was to compare relative body fat (% fat) in female field hockey players using several methods with dual-energy X-ray absorptiometry (DXA) as the reference. Participants were 31 Polish hockey players 16-30 years of age, 17 national and 14 youth level. Percent body fat was estimated by DXA (reference method), conventional and segmental bioelectrical impedance analysis (BIA), and predicted from skinfolds (SKF). National and youth team members did not differ in estimated body fat. Correlations between BIA and skinfold estimates of % fat and DXA % fat though significant, were moderate. Both % fat SKF and % fat SBIA differed significantly from % fat DXA, while estimated % fat BIA and % fat DXA did not differ. Limits of agreement were narrow for conventional BIA (-1.20 to 1.71% fat), followed by segmental BIA (3.72-6.09% fat) and broadest for SKF (5.97-9.28% fat). Differences between DXA % fat and estimated % fat with SKF and SBIA increased from the leanest to fattest athletes, whereas conventional BIA overestimated % fat relative to DXA in the small sample of individuals with low relative fatness and underestimated % fat in individuals with elevated relative fatness. Estimated % fat from conventional BIA most closely approximated DXA % fat in this sample of female field hockey players suggesting that the method may be suitable for field surveys to monitor body composition during the season.

Measuring body composition in low-resource settings across the life course

We explore recent advances in the field of body composition measurement that could be suitable for use in low-resource settings across the life-course. Our aim was three-fold: (i) to review the available literature and information on both current and novel technologies for body composition measurement, (ii) to present a decision schema that may assist in selecting the appropriate body composition technology, and (iii) which of the technologies available are suitable for low-resource settings based on cost, infrastructure needed, participant compliance needed for the measurement, quality assurance protocols in place, safety, accuracy of measurement and training required.