Gut Microbiome Wellness Index 2 for Enhanced Health Status Prediction from Gut Microbiome Taxonomic Profiles.

Recent advancements in human gut microbiome research have revealed its crucial role in shaping innovative predictive healthcare applications. We introduce Gut Microbiome Wellness Index 2 (GMWI2), an advanced iteration of our original GMWI prototype, designed as a robust, disease-agnostic health status indicator based on gut microbiome taxonomic profiles. Our analysis involved pooling existing 8069 stool shotgun metagenome data across a global demographic landscape to effectively capture biological signals linking gut taxonomies to health. GMWI2 achieves a cross-validation balanced accuracy of 80% in distinguishing healthy (no disease) from non-healthy (diseased) individuals and surpasses 90% accuracy for samples with higher confidence (i.e., outside the "reject option"). The enhanced classification accuracy of GMWI2 outperforms both the original GMWI model and traditional species-level α-diversity indices, suggesting a more reliable tool for differentiating between healthy and non-healthy phenotypes using gut microbiome data. Furthermore, by reevaluating and reinterpreting previously published data, GMWI2 provides fresh insights into the established understanding of how diet, antibiotic exposure, and fecal microbiota transplantation influence gut health. Looking ahead, GMWI2 represents a timely pivotal tool for evaluating health based on an individual's unique gut microbial composition, paving the way for the early screening of adverse gut health shifts. GMWI2 is offered as an open-source command-line tool, ensuring it is both accessible to and adaptable for researchers interested in the translational applications of human gut microbiome science.

CT-derived psoas muscle area and density are associated with length of stay and discharge disposition after liver transplantation.

BACKGROUND & AIMS: Prolonged length of stay (LOS) and discharge disposition following liver transplantation are associated with postoperative complications and increased healthcare utilization. This study evaluated the relationship between CT-derived psoas muscle measurements and hospital LOS, intensive care unit (ICU) LOS, and discharge disposition after liver transplant. The psoas muscle was chosen given its ease of measurement with any radiological software. A secondary analysis assessed the relationship between the American Society for Parenteral and Enteral Nutrition and the Academy of Nutrition and Dietetics (ASPEN/AND) malnutrition diagnosis criteria and CT-derived psoas muscle measures. METHODS: CT-derived measures of psoas muscle density (mHU) and cross-sectional area at the level of the third lumbar vertebrae were obtained from preoperative CT scans of liver transplant recipients. Cross-sectional area measures were corrected for body size to generate a psoas area index variable (cm2/m2; PAI). RESULTS: Each 1-unit increase in PAI was associated with a reduced hospital LOS of 4 days (R2 = 0.07). Each 5-unit increase in mean Hounsfield units (mHU) was associated with a reduced hospital and ICU LOS of 5 and 1.6 days, respectively (R2 = 0.22 and 0.14, respectively). Mean PAI and mHU were higher in patients who discharged to home. PAI was reasonably identified through ASPEN/AND malnutrition criteria, but there was no difference in mHU between those with and without malnutrition. CONCLUSION: Measures of psoas density were associated with both hospital and ICU LOS and discharge disposition. PAI was associated with hospital LOS and discharge disposition. CT-derived measures of psoas density may be a valuable complement to preoperative liver transplant nutrition assessment using traditional ASPEN/AND malnutrition criteria.

AGA Clinical Practice Guideline on Pharmacological Interventions for Adults With Obesity

Pharmacological management of obesity improves outcomes and decreases the risk of obesity-related complications. This American Gastroenterological Association guideline is intended to support practitioners in decisions about pharmacological interventions for overweight and obesity. A multidisciplinary panel of content experts and guideline methodologists used the Grading of Recommendations Assessment, Development and Evaluation framework to prioritize clinical questions, identify patient-centered outcomes, and conduct an evidence synthesis of the following agents: semaglutide 2.4 mg, liraglutide 3.0 mg, phentermine-topiramate extended-release (ER), naltrexone-bupropion ER, orlistat, phentermine, diethylpropion, and Gelesis100 oral superabsorbent hydrogel. The guideline panel used the evidence-to-decision framework to develop recommendations for the pharmacological management of obesity and provided implementation considerations for clinical practice. The guideline panel made 9 recommendations. The panel strongly recommended the use of pharmacotherapy in addition to lifestyle intervention in adults with overweight and obesity (body mass index ≥30 kg/m2, or ≥27 kg/m2 with weight-related complications) who have an inadequate response to lifestyle interventions. The panel suggested the use of semaglutide 2.4 mg, liraglutide 3.0 mg, phentermine-topiramate ER, and naltrexone-bupropion ER (based on moderate certainty evidence), and phentermine and diethylpropion (based on low certainty evidence), for long-term management of overweight and obesity. The guideline panel suggested against the use of orlistat. The panel identified the use of Gelesis100 oral superabsorbent hydrogel as a knowledge gap. In adults with overweight and obesity who have an inadequate response to lifestyle interventions alone, long-term pharmacological therapy is recommended, with multiple effective and safe treatment options.

AGA Clinical Practice Guideline on Pharmacological Interventions for Adults With Obesity.

BACKGROUND & AIMS: Pharmacological management of obesity improves outcomes and decreases the risk of obesity-related complications. This American Gastroenterological Association guideline is intended to support practitioners in decisions about pharmacological interventions for overweight and obesity. METHODS: A multidisciplinary panel of content experts and guideline methodologists used the Grading of Recommendations Assessment, Development and Evaluation framework to prioritize clinical questions, identify patient-centered outcomes, and conduct an evidence synthesis of the following agents: semaglutide 2.4 mg, liraglutide 3.0 mg, phentermine-topiramate extended-release (ER), naltrexone-bupropion ER, orlistat, phentermine, diethylpropion, and Gelesis100 oral superabsorbent hydrogel. The guideline panel used the evidence-to-decision framework to develop recommendations for the pharmacological management of obesity and provided implementation considerations for clinical practice. RESULTS: The guideline panel made 9 recommendations. The panel strongly recommended the use of pharmacotherapy in addition to lifestyle intervention in adults with overweight and obesity (body mass index ≥30 kg/m2, or ≥27 kg/m2 with weight-related complications) who have an inadequate response to lifestyle interventions. The panel suggested the use of semaglutide 2.4 mg, liraglutide 3.0 mg, phentermine-topiramate ER, and naltrexone-bupropion ER (based on moderate certainty evidence), and phentermine and diethylpropion (based on low certainty evidence), for long-term management of overweight and obesity. The guideline panel suggested against the use of orlistat. The panel identified the use of Gelesis100 oral superabsorbent hydrogel as a knowledge gap. CONCLUSIONS: In adults with overweight and obesity who have an inadequate response to lifestyle interventions alone, long-term pharmacological therapy is recommended, with multiple effective and safe treatment options.

Ultrasound measurements of abdominal muscle thickness are associated with postmenstrual age at full oral feedings in preterm infants: A preliminary study.

BACKGROUND: A premature infant's discharge from the neonatal intensive care unit (NICU) is dependent on factors such as respiratory stability, adequate growth, and the ability to consume oral feeds. Once infants have achieved respiratory stability, a tool that can better predict age at discharge is desirable. Thus, we conducted a secondary data analysis to assess the association between ultrasound measurements of abdominal muscle thickness and postmenstrual age (PMA) at full oral feedings. METHODS: Forty-nine (n = 49) healthy, premature infants (mean gestational age = 32 weeks) were recruited from the NICU. Anthropometric measurements and ultrasound measurements of the rectus abdominis were conducted when infants were medically stable. Fat-free mass (FFM) was obtained using air displacement plethysmography. The relationship between ultrasound measurements of muscle thickness and PMA at full oral feedings was assessed using linear regression analysis. The relationship between FFM z-scores and PMA at full oral feedings was also assessed for comparison. RESULTS: When adjusting for gestational age at birth, PMA at measurement, days of positive pressure respiratory support, weight, and length, ultrasound measurements of abdominal muscle thickness were independently, negatively associated with PMA at full oral feedings (ß estimate: -0.71, P = .03). CONCLUSION: Preliminary results suggest infants with greater abdominal muscle thickness may reach full oral feedings at an earlier PMA (nearly 1 week per millimeter). Thus, ultrasound measurements of abdominal muscle thickness may be helpful in assessing readiness for discharge in healthy preterm infants. Further research is needed for development and validation of a prediction equation.

The Comparison of Segmental Multifrequency Bioelectrical Impedance Analysis and Dual-Energy X-ray Absorptiometry for Estimating Fat Free Mass and Percentage Body Fat in an Ambulatory Population.

BACKGROUND: Despite malnutrition being associated with increased mortality and morbidity, there continues to be great difficulty in defining criteria and implementing widespread screening. Tools used to diagnose decreased fat-free mass (FFM [sarcopenia]) should be easy to use, relatively inexpensive, and safe. Bioelectrical impedance analysis (BIA) has the potential to meet these criteria, but reliability across body mass index (BMI) classes is a concern. METHODS: A total of 176 healthy ambulatory participants (aged 18-65 years) were recruited equally (n = 44) in 4 BMI categories: (1) 18.5-24.9, (2) 25.0-29.9, (3) 30-34.9, and (4) ≥35.0. Participants were fasting overnight and had S-MFBIA (InBody 770) measurements the next morning, with DXA being performed subsequently within 30 minutes. RESULTS: The measurement (mean ± SD) for FFM with DXA was 52.8 ± 11.0, and BIA was 53.6 ± 11.0. Delta (S-MFBIA vs DXA) was 0.8 ± 2.2 (5% limits of agreement -3.5 to +5.2), and concordance correlation coefficient (CCC) was 0.98 (95% CI, 0.97-0.98). The measurements (mean ± SD) for PBF with DXA was 37.5 ± 10.6% and S-MFBIA was 36.6 ± 11.3%. Delta (S-MFBIA vs DXA) was -0.9 ± 2.6 (5% limits of agreement 6.0 to +4.2), and CCC was 0.97 (95% CI, 0.96-0.98). The CCC according to the 4 BMI groups for FFM and PBF was between 0.96-0.98 and 0.90-0.94, respectively. CONCLUSIONS: FFM and PBF measured by S-MFBIA had good agreement with DXA across all BMI categories measured in the current study of ambulatory participants.

Use of Exclusive Enteral Formula Diet as Adjunctive Therapy for Treatment of a Crohn's Disease Flare.

Introduction: We report the case of an adult patient who achieved remission of a Crohn's disease flare after treatment with exclusive enteral nutrition as adjunctive therapy to medication. Case Report: A 46-year-old man with severe, stricturing Crohn's presented for severe abdominal pain and weight loss; estimated Crohn's Disease Activity Index score greater than 300. Antibiotics, vedolizumab, budesonide, and exclusive enteral nutrition diet were instituted. Approximately 30 days later, his Crohn's Disease Activity Index score improved to 170. Discussion: This case illustrates the possible utility of an exclusive enteral formula diet as an adjunct to medication to induce remission of a Crohn's disease flare.

Dietary Factors in Sulfur Metabolism and Pathogenesis of Ulcerative Colitis.

The biogeography of inflammation in ulcerative colitis (UC) suggests a proximal to distal concentration gradient of a toxin. Hydrogen sulfide (H2S) has long been considered one such toxin candidate, and dietary sulfur along with the abundance of sulfate reducing bacteria (SRB) were considered the primary determinants of H2S production and clinical course of UC. The metabolic milieu in the lumen of the colon, however, is the result of a multitude of factors beyond dietary sulfur intake and SRB abundance. Here we present an updated formulation of the H2S toxin hypothesis for UC pathogenesis, which strives to incorporate the interdependency of diet composition and the metabolic activity of the entire colon microbial community. Specifically, we suggest that the increasing severity of inflammation along the proximal-to-distal axis in UC is due to the dilution of beneficial factors, concentration of toxic factors, and changing detoxification capacity of the host, all of which are intimately linked to the nutrient flow from the diet.

Impact of Software Selection and ImageJ Tutorial Corrigendum on Skeletal Muscle Measures at the Third Lumbar Vertebra on Computed Tomography Scans in Clinical Populations.

BACKGROUND: There is growing interest in computed tomography (CT) measures of skeletal muscle cross-sectional area (CSA) for nutrition assessment. Multiple software programs are available, but little work has been done comparing programs. We aimed to determine if CT-derived measures of skeletal muscle CSA at the level of the L3 are influenced by the software program used. We also demonstrate the importance of the ImageJ corrigendum published in this journal. METHODS: Two software programs, National Institutes of Health ImageJ and Tomovision sliceOmatic, were compared. ImageJ measures were obtained using both the original tutorial and corrigendum instructions. Skeletal muscle CSA at the level of the L3 was measured in advanced heart failure and head and neck cancer populations by 3 different investigators. Intraclass correlation coefficients were used to calculate intrarater and interrater reliability. Bland-Altman analysis was used to assess agreement. RESULTS: Both software programs yielded excellent intrarater and interrater reliability scores (intraclass correlation coefficients, 0.985-1.000). The overall mean difference (ImageJ tutorial with corrigendum - sliceOmatic) for the entire sample (N = 51) was found to be 1.53 cm2 (95% CI, 0.59-2.47 cm2 ). The overall mean difference (ImageJ corrected - original) for the entire sample (N = 51) was found to be -11.35 cm2 (95% CI, -12.75 to -9.95 cm2 ). CONCLUSION: Measures of skeletal muscle CSA at the L3 were found to be ∼1.53 cm2 higher with ImageJ than sliceOmatic. This difference was not found to affect interpretation against a published cut point. The importance of accounting for the ImageJ tutorial corrigendum was shown to be clinically significant when applied to published cut points.

Diagnosing clinical malnutrition: Perspectives from the past and implications for the future.

This review, intended for both researchers and clinicians, provides a history of the definition of clinical malnutrition. Despite global efforts, we remain without one clear, objective, internationally accepted definition; clarity in this regard will ultimately improve our evaluation and monitoring of nutritional status to achieve optimal patient outcomes. In this review we explore the development of the term malnutrition and its diagnosis and application in the setting of acute and chronic disease. We begin in the second century A.D. with the work of the Greek physician Galen who is credited as the first to apply the term marasmus to characterize three categories of malnutrition, which are surprisingly similar to components of current international definitions. We then highlight significant developments over the next 2000 years culminating in our current application of the clinical diagnosis of malnutrition. A perspective on historical practices may inform current efforts toward a global definition and diagnosis of malnutrition.

Use of both quantitative and qualitative methods to improve assessment of resting energy expenditure equation performance in hospitalized adults.

OBJECTIVE: To introduce the use of qualitative assessment in energy expenditure (EE) equation research to improve the understanding of performance of the equations in the clinical setting. PATIENTS AND METHODS: Hospitalized individuals who had an indirect calorimetry (IC) measurement during their hospital stay from 2010 to 2012 were included in the study (n = 59). An additional 1000 patients hospitalized during this time were used to limit the IC cohort to a more "clinically relevant" BMI range (n = 46). The following estimation equations were assessed: Harris-Benedict, 25 kcal/kg using actual body weight, Mifflin St. Jeor, Ireton-Jones, Penn State, and Owen. Bland-Altman plots with Loess curves were generated to compare estimated basal caloric needs between EE equations and IC values. RESULTS: This study found a large amount of variability with all EE equations. As the mean calorie level increased, the Harris Benedict, Mifflin St. Jeor, Penn State, and Owen equations all tended to increasingly under-predict caloric need. CONCLUSION: In a research setting a qualitative assessment of EE equations can provide a more comprehensive understanding of equation performance by complementing traditional quantitative methods. The addition of a Loess curve to the Bland-Altman plot further enhances qualitative assessment.

Preoperative Pectoralis Muscle Quantity and Attenuation by Computed Tomography Are Novel and Powerful Predictors of Mortality After Left Ventricular Assist Device Implantation.

BACKGROUND: Skeletal muscle mass decreases in end-stage heart failure and is predictive of clinical outcomes in several disease states. Skeletal muscle attenuation and quantity as quantified on preoperative chest computed tomographic scans may be predictive of mortality after continuous flow (CF) left ventricular assist device (LVAD) implantation. METHODS AND RESULTS: A single-center continuous flow-LVAD database (n=354) was used to identify patients with chest computed tomographies performed in the 3 months before LVAD implantation (n=143). Among patients with computed tomography data available, unilateral pectoralis muscle mass indexed to body surface area and attenuation (approximated by mean Hounsfield units [PHUm]) were measured in each patient with a high intrarater and inter-rater reliability (intraclass correlation coefficients 0.98 and 0.97, respectively). Multivariate Cox regression analyses were performed, censoring at cardiac transplantation, to assess the impact of preoperative pectoralis muscle index and pectoralis muscle mean Hounsfield unit on survival after LVAD implantation. Each unit increase in pectoralis muscle index was associated with a 27% reduction in the hazard of death after LVAD (adjusted hazard ratio, 0.73; 95% confidence interval, 0.58-0.92; P=0.007). Each 5-U increase in pectoralis muscle mean Hounsfield unit was associated with a 22% reduction in the hazard of death after LVAD (adjusted hazard ratio, 0.78; 95% confidence interval, 0.68-0.89; P<0.0001). Pectoralis muscle index and pectoralis muscle mean Hounsfield unit outperformed other traditional measures in the data set, including the HeartMate II risk score. CONCLUSIONS: Pectoralis muscle size and attenuation were powerful predictors of outcomes after LVAD implantation in this data set. This one time, repeatable, internal assessment of patient substrate added valuable prognostic information that was not available on standard preoperative testing.

Avaliação de modelos avançados de espectroscopia de bioimpedância para medir a composição do corpo em adultos saudáveis (NHANES 1999-2004) e aqueles que sofrem perda de peso em massa após a cirurgia de bypass gástrico Roux-en-Y / Evaluation of Advanced Bioimpedance Spectroscopy Models for Measuring Body Composition in Healthy Adults (NHANES 19992004) and Those Undergoing Massive Weight Loss Following Roux-en-Y Gastric Bypass Surgery

Introduction: Bioimpedance spectroscopy (BIS) devices utilize biophysical modeling to generate body composition data. The addition of body mass index (BMI) to modified Xitron-Hanai-based mixture equations improved BIS estimates of intracellular water (ICW), particularly at the extremes of BMI. A 3-compartment model for distinguishing excess fluid (ExF) from normally hydrated lean (NHLT) and adipose tissue may further improve BIS estimates. Objective:We aimed to validate a BIS approach based on the Chamney model for determining fat mass (FM) in healthy individuals (NHANES) and for measuring FM changes in individuals undergoing massive weight loss. Methods: Using adult NHANES 1999-2004 (2821 female, 3063 male) and longitudinal pre-topost-RYGB (15F) data, we compared dual-energy-X-ray absorptiometry (DXA) and BIS for FM. We applied BIS adiposity-corrected values to Chamney equations for normally hydrated lean and adipose tissue (NHLT, NHAT) and FM. Method agreement was evaluated by correlations, paired t-tests, root mean square error (RMSE), BlandAltman (B-A) analysis, and concordance correlation coefficients (CCC). Results: Method agreement between BIS and DXAFM was good in healthy adults (r=0.96, CCC=0.93, p<.0001), and pre-to-post-RYGB (r=0.93-0.98, CCC=0.81-0.86, p<.001). Although cross-sectional FM measures differed, FM change measures post-RYGB did not (35.6±8.9 vs. 35.2±9.2 kg, BIS vs. DXA) and agreed well (r=0.84, p<.0001). The 15 subjects with follow-up measurements at 1 year lost 11.5±9.8 kg FFM by DXA, but only 1.3±2.5 kg of NHLT by BIS, suggesting that the FFM loss may have been mostly adipose tissue water. Conclusions: Incorporation of the Chamney model into BIS algorithms is a major conceptual advancement for assessing and monitoring body composition. Its ability to differentiate ICW and extracellular water (ECW) in NHLT and NHAT, as well as excess ECW is promising, and would facilitate lean tissue monitoring in obesity and acute/chronic disease.(AU)

Introdução: Os dispositivos de espectroscopia de bioimpedância (DEB) utilizam modelagem biofísica para gerar dados de composição corporal. A adição do índice de massa corporal (IMC) às equações de mistura modificadas com Xitron-Hanai modificadas melhorou as estimativas de DEB de água intracelular (AI), particularmente nos casos extremos do IMC. Um modelo de 3 compartimentos para distinguir o excesso de fluido (ExF) de magro normalmente hidratado (NHLT) e tecido adiposo pode ainda melhorar as estimativas do DEB. Objetivo: Pretendemos validar uma abordagem do DEB com base no modelo de Chamney para determinar a massa de gordura (MG) em indivíduos saudáveis (NHANES) e para medir mudanças de MG em indivíduos submetidos à perda de peso maciça. Método: Usando o NHANES adulto 1999-2004 (2821 mulheres, 3063 homens) e dados longitudinais pré-pós-RYGB (15 F), comparamos a absorção de raios-X de dupla energia (DXA) e DEB para MG. Aplicamos os valores corrigidos de adiposidade do BIS às equações de Chamney para tecidos magros e adiposos normalmente hidratados (NHLT, NHAT) e FM. O acordo de método foi avaliado por correlações, testes t pareados, erro quadrado médio (EQM), análise Bland-Altman (B-A) e coeficientes de correlação de concordância (CCC). Resultados: O acordo de método entre DEB e DXA MG foi bom em adultos saudáveis (r=0,96, CCC=0,93, p<.0001) e pré-pós-RYGB (r=0,93-0,98, CCC=0,81-0,86, p<0,001). Embora as medidas de MG transversais diferissem, as medidas de mudança de MG pós-RYGB não (35,6±8,9 vs. 35,2±9,2 kg, DEBvs. DXA) e concordaram bem (r=0,84, p<.0001). Os 15 sujeitos com medidas de seguimento ao 1 ano perderam 11,5±9,8 kg FFM por DXA, mas apenas 1,3±2,5 kg de NHLT pelo DEB, sugerindo que a perda de FFM pode ter sido principalmente água do tecido adiposo. Conclusões: A incorporação do modelo de Chamney em algoritmos DEB é um grande avanço conceitual para avaliar e monitorar a composição corporal. A sua capacidade de diferenciar AI e água extracelular (AE) no NHLT e NHAT, bem como o excesso de AE é promissor e facilitará a monitorização do tecido magro na obesidade e doença aguda/crônica.(AU)

Evaluation of Advanced Bioimpedance Spectroscopy Models for Measuring Body Composition in Healthy Adults (NHANES 1999-2004) and Those Undergoing Massive Weight Loss Following Roux-en-Y Gastric Bypass Surgery.

INTRODUCTION: Bioimpedance spectroscopy (BIS) devices utilize biophysical modeling to generate body composition data. The addition of body mass index (BMI) to modified Xitron-Hanai-based mixture equations improved BIS estimates of intracellular water (ICW), particularly at the extremes of BMI. A 3-compartment model for distinguishing excess fluid (ExF) from normally hydrated lean (NHLT) and adipose tissue may further improve BIS estimates. OBJECTIVE: We aimed to validate a BIS approach based on the Chamney model for determining fat mass (FM) in healthy individuals (NHANES) and for measuring FM changes in individuals undergoing massive weight loss. METHODS: Using adult NHANES 1999-2004 (2821 female, 3063 male) and longitudinal pre-to-post-RYGB (15F) data, we compared dual-energy-X-ray absorptiometry (DXA) and BIS for FM. We applied BIS adiposity-corrected values to Chamney equations for normally hydrated lean and adipose tissue (NHLT, NHAT) and FM. Method agreement was evaluated by correlations, paired t-tests, root mean square error (RMSE), Bland-Altman (B-A) analysis, and concordance correlation coefficients (CCC). RESULTS: Method agreement between BIS and DXAFM was good in healthy adults (r=0.96, CCC=0.93, p<.0001), and pre-to-post-RYGB (r=0.93-0.98, CCC=0.81-0.86, p<.001). Although cross-sectional FM measures differed, FM change measures post-RYGB did not (35.6±8.9 vs. 35.2±9.2 kg, BIS vs. DXA) and agreed well (r=0.84, p<.0001). The 15 subjects with follow-up measurements at 1 year lost 11.5±9.8 kg FFM by DXA, but only 1.3±2.5 kg of NHLT by BIS, suggesting that the FFM loss may have been mostly adipose tissue water. CONCLUSIONS: Incorporation of the Chamney model into BIS algorithms is a major conceptual advancement for assessing and monitoring body composition. Its ability to differentiate ICW and extracellular water (ECW) in NHLT and NHAT, as well as excess ECW is promising, and would facilitate lean tissue monitoring in obesity and acute/chronic disease.

INTRODUÇÃO: Os dispositivos de espectroscopia de bioimpedância (DEB) utilizam modelagem biofísica para gerar dados de composição corporal. A adição do índice de massa corporal (IMC) às equações de mistura modificadas com Xitron-Hanai modificadas melhorou as estimativas de DEB de água intracelular (AI), particularmente nos casos extremos do IMC. Um modelo de 3 compartimentos para distinguir o excesso de fluido (ExF) de magro normalmente hidratado (NHLT) e tecido adiposo pode ainda melhorar as estimativas do DEB. OBJETIVO: Pretendemos validar uma abordagem do DEB com base no modelo de Chamney para determinar a massa de gordura (MG) em indivíduos saudáveis (NHANES) e para medir mudanças de MG em indivíduos submetidos à perda de peso maciça. MÉTODO: Usando o NHANES adulto 1999­2004 (2821 mulheres, 3063 homens) e dados longitudinais pré-pós-RYGB (15 F), comparamos a absorção de raios-X de dupla energia (DXA) e DEB para MG. Aplicamos os valores corrigidos de adiposidade do BIS às equações de Chamney para tecidos magros e adiposos normalmente hidratados (NHLT, NHAT) e FM. O acordo de método foi avaliado por correlações, testes t pareados, erro quadrado médio (EQM), análise Bland-Altman (B-A) e coeficientes de correlação de concordância (CCC). RESULTADOS: O acordo de método entre DEB e DXA MG foi bom em adultos saudáveis (r=0,96, CCC=0,93, p<.0001) e pré-pós-RYGB (r=0,93­0,98, CCC=0,81­0,86, p<0,001). Embora as medidas de MG transversais diferissem, as medidas de mudança de MG pós-RYGB não (35,6±8,9 vs. 35,2±9,2 kg, DEBvs. DXA) e concordaram bem (r=0,84, p<.0001). Os 15 sujeitos com medidas de seguimento ao 1 ano perderam 11,5±9,8 kg FFM por DXA, mas apenas 1,3±2,5 kg de NHLT pelo DEB, sugerindo que a perda de FFM pode ter sido principalmente água do tecido adiposo. CONCLUSÕES: A incorporação do modelo de Chamney em algoritmos DEB é um grande avanço conceitual para avaliar e monitorar a composição corporal. A sua capacidade de diferenciar AI e água extracelular (AE) no NHLT e NHAT, bem como o excesso de AE é promissor e facilitará a monitorização do tecido magro na obesidade e doença aguda/crônica.

Phase Angle and Impedance Ratio: Reference Cut-Points From the United States National Health and Nutrition Examination Survey 1999-2004 From Bioimpedance Spectroscopy Data.

BACKGROUND: Raw bioimpedance parameters (eg, 50-kHz phase angle [PA] and 200-kHz/5-kHz impedance ratio [IR]) have been investigated as predictors of nutrition status and/or clinical outcomes. However, their validity as prognostic measures depends on the availability of appropriate reference data. Using a large and ethnically diverse data set, we aimed to determine if ethnicity influences these measures and provide expanded bioimpedance reference data for the U.S. METHODS: The National Health and Nutrition Examination Survey (NHANES) is an ongoing compilation of studies conducted by the U.S. Centers for Disease Control and Prevention designed to monitor nutrition status of the U.S. POPULATION: The NHANES data sets analyzed were from the years 1999-2000, 2001-2002, and 2003-2004. RESULTS: Multivariate analysis showed that PA and IR differed by body mass index (BMI), age, sex, and ethnicity (n = 6237; R2 = 41.2%, P < .0001). Suggested reference cut-points for PA stratified by age decade, ethnicity, and sex are provided. CONCLUSION: Ethnicity is an important variable that should be accounted for when determining population reference values for PA and IR. We have provided sex-, ethnicity-, and age decade-specific reference values from PA for use by future studies in U.S. POPULATIONS: Interdevice differences are likely to be important contributors to variability across published population-specific reference data and, where possible, should be evaluated in future research. Ultimately, further validation with physiologically relevant reference measures (eg, dual-energy x-ray absorptiometry) is necessary to determine if PA/IR are appropriate bedside tools for the assessment of nutrition status in a clinical population.

The Use of Technology for Estimating Body CompositionStrengths and Weaknesses of Common Modalities in a Clinical Setting [Formula: see text].

Assessment of body composition, both at single time points and longitudinally, is particularly important in clinical nutrition practice. It provides a means for the clinician to characterize nutrition status at a single time point, aiding in the identification and diagnosis of malnutrition, and to monitor changes over time by providing real-time information on the adequacy of nutrition interventions. Objective body composition measurement tools are available clinically but are often underused in nutrition care, particularly in the United States. This is, in part, due to a number of factors concerning their use in a clinical context: cost and accessibility of equipment, as well as interpretability of the results. This article focuses on the factors influencing interpretation of results in a clinical setting. Body composition assessment, regardless of the method, is inherently limited by its indirect nature. Therefore, an understanding of the strengths and limitations of any method is essential for meaningful interpretation of its results. This review provides an overview of body composition technologies available clinically (computed tomography, dual-energy x-ray absorptiometry, bioimpedance, ultrasound) and discusses the strengths and limitations of each device.

The Influence of Bariatric Surgery on Serum Bile Acids in Humans and Potential Metabolic and Hormonal Implications: a Systematic Review.

Recent research suggests a mechanistic role for bile acids (BA) in the metabolic improvement following bariatric surgery. It is believed that the hormonal and metabolic effects associated with changes in systemic BAs may be related to the farnesoid X receptor (FXR) and a G-protein coupled receptor (TGR5). This systematic review examines changes in systemic BAs following bariatric procedures. Studies were included if they reported the measurement of systemic BAs in humans at at least one time point after bariatric surgery. Eleven papers were identified that met the inclusion criteria. Seven studies reported the effect of Roux-en-Y gastric bypass (RYGB) on fasting BAs. The majority (6/7) reported that fasting BAs increased after RYGB. Data regarding fasting BAs after vertical sleeve gastrectomy (VSG) and laparoscopic gastric banding (LAGB) are inconsistent. Data regarding post-prandial BA changes after RYGB, VSG, and LAGB are also inconsistent. More research is needed to investigate the connection between BAs and the metabolic improvement seen after bariatric surgery.