Doubly labelled water for determining total energy expenditure in adult critically ill and acute care hospitalized inpatients: A scoping review.

BACKGROUND & AIMS: Doubly labelled water (DLW) is considered the reference standard method of measuring total energy expenditure (TEE), but there is limited information on its use in the Intensive Care Unit (ICU) and acute care setting. This scoping review aims to systematically summarize the available literature on TEE measured using DLW in these contexts. METHODS: Four online databases (MEDLINE, Embase, Emcare and CINAHL) were searched up to Dec 12, 2020. Studies in English were included if they measured TEE using DLW in adults in the ICU and/or acute care setting. Key considerations, concerns and practical recommendations were identified and qualitatively synthesized. RESULTS: The search retrieved 7582 studies and nine studies were included; one in the ICU and eight in the acute care setting. TEE was measured over 7-15-days, in predominantly clinically stable patients. DLW measurements were not commenced until four days post admission or surgery in one study and following a 10-14-day stabilization period on parenteral nutrition (PN) in three studies. Variable dosages of isotopes were administered, and several equations used to calculate TEE. Four main considerations were identified with the use of DLW in these settings: variation in background isotopic abundance; excess isotopes leaving body water as carbon dioxide or water; fluctuations in rates of isotope elimination and costs. CONCLUSION: A stabilization period on intravenous fluid and PN regimens is recommended prior to DLW measurement. The DLW technique can be utilized in medically stable ICU and acute care patients, with careful considerations given to protocol design.

Nutrition Status and Health-Related Quality of Life Among Outpatients With Advanced Head and Neck Cancer.

This pilot study evaluated nutrition status and health-related quality of life (HRQOL) outcomes among outpatients with head and neck cancer (HNC). Data were collected from 19 patients (18 males, 1 female) during 3 time points: once before chemoradiotherapy (CRT) initiation and 1 and 3 months after CRT. Nutrition status was evaluated using the Scored Patient-Generated Subjective Global Assessment (PG-SGA). Malnutrition was defined as PG-SGA stage B (moderate/suspected malnutrition) or stage C (severely malnourished). HRQOL was assessed through the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30) and its HNC-specific module (QLQ-H&N35). We found that well-nourished patients reported having fewer issues with pain, fatigue, appetite loss, chewing, sticky saliva, coughing, and social eating than those categorized as malnourished (P < .05). The association between the global quality-of-life score and PG-SGA score was statistically significant but weak in strength (r = -0.37, P = .012). Although PG-SGA identified 70% as either moderately or severely malnourished before treatment initiation, the mean body mass index was in the overweight category (29 ± 5 kg/m2 ). Compared with pretreatment, patients reported more severe problems with chewing, swallowing, sticky saliva, dry mouth, speech, social eating, and taste and smell sensations at 1-month follow-up, although issues with dry mouth persisted 3 months post treatment (P = .003). In conclusion, malnourished patients reported having worse HRQOL symptoms compared with well-nourished patients. Routine nutrition and psychosocial assessment through PG-SGA and EORTC tools might help identify patients in need of nutrition and psychosocial care.

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.

Malnutrition Identified by the Academy of Nutrition and Dietetics and American Society for Parenteral and Enteral Nutrition Consensus Criteria and Other Bedside Tools Is Highly Prevalent in a Sample of Individuals Undergoing Treatment for Head and Neck Cancer.

BACKGROUND: Using the Academy of Nutrition and Dietetics and American Society for Parenteral and Enteral Nutrition (Academy/ASPEN) Consensus malnutrition definition, we estimated malnutrition prevalence in a sample of individuals with head and neck cancer (HNC) and compared it with the Patient-Generated Subjective Global Assessment (PG-SGA). We also investigated the utility of the 50-kHz phase angle (PA) and 200-kHz/5-kHz impedance ratio (IR) to identify malnutrition. MATERIALS AND METHODS: Nineteen individuals (18 males, 1 female) scheduled to undergo chemoradiotherapy were seen at 5 time points during and up to 3 months after treatment completion. Multiple-frequency bioelectrical impedance analysis, PG-SGA, nutrition-focused physical examination, anthropometry, dietary intake, and handgrip strength data were collected. RESULTS: Using the Consensus, 67% were found to be malnourished before treatment initiation; these criteria diagnosed malnutrition with overall good sensitivity (94%) and moderate specificity (43%) compared with PG-SGA. Over all pooled observations, "malnourished" (by Consensus but not PG-SGA category) had a lower mean PA (5.2 vs 5.9; P = .03) and higher IR (0.82 vs 0.79; P = .03) than "well-nourished" categorizations, although the clinical relevance of these findings is unclear. PA and IR were correlated with higher PG-SGA score (r = -0.35, r = 0.36; P < .01) and handgrip strength (r = 0.48, r = -0.47; P < .01). CONCLUSION: The Academy/ASPEN Consensus and the PG-SGA were in good agreement. It is unclear whether PA and IR can be used as surrogate markers of nutrition status or muscle loss.

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)

Long-Term Body Composition Changes in Women Following Roux-en-Y Gastric Bypass Surgery.

BACKGROUND: Although most individuals experience successful weight loss following Roux-en-Y gastric bypass (RYGB), weight regain is a concern, the composition of which is not well documented. Our aim was to evaluate changes in body composition and handgrip strength as a measure of functional status in participants from a previous 1-year post-RYGB longitudinal study who had undergone RYGB approximately 9 years prior. METHODS: Five women from an original larger cohort were monitored pre-RYGB and 1.5 months, 6 months, 1 year, and 9 years post-RYGB. Body composition was assessed at all time points using dual energy x-ray absorptiometry and multiple dilution. Handgrip strength was measured using a digital isokinetic hand dynamometer (Takei Scientific Instruments, Ltd, Tokyo, Japan). RESULTS: Mean time to final follow-up was 8.7 years. Lean soft tissue (LST) loss over the ~9-year period was on average 11.9 ± 5.6 kg. Compared with 1-year post-RYGB, 9-year LST was 4.4 ± 3.0 kg lower ( P = .03). Fat-free mass decreased over the 9-year period by 12.6 ± 5.8 kg. Mean fat mass (FM) decreased from 75.4 ± 22.6 kg pre-RYGB to 35.5 ± 21.5 kg 1 year post-RYGB but then trended toward an increase of 8.6 ± 7.0 kg between 1 year and 9 years post-RYGB ( P = .053). Loss of LST was correlated with loss of handgrip strength ( r = 0.64, P = .0005). CONCLUSION: The continued loss of lean mass associated with decreased handgrip strength occurring with long-term trend toward FM regain post-RYGB is concerning. The loss of LST and functional strength carries particular implications for the aging bariatric population and should be investigated further.

Eating patterns and food choice as determinant of weight loss and improvement of metabolic profile after RYGB.

OBJECTIVE: Significant changes in the preference for different dietary components have been observed after Roux-en-Y gastric bypass (RYGB). The aim of this study was to evaluate the early post-RYGB changes in quality of eating patterns and their relationship to weight loss and metabolic parameters. METHODS: The sample was composed of 41 extremely obese individuals undergoing RYGB. Dietary data were collected using a validated food frequency questionnaire in Brazil. A food intake evaluation was conducted with a focus on the frequency of consumption (≥4 times/wk) of markers for healthy eating and markers for unhealthy eating. Furthermore, anthropometric and metabolic markers were collected before surgery and 6 mo post-RYGB. RESULTS: Compared with baseline, the postsurgery body mass index was reduced by 12.9 kg/m2, corresponding to an excess weight loss of 63.5%. Blood glucose, insulin, ferritin, cholesterol, low-density lipoprotein-cholesterol, triacylglycerol (TG), and hemoglobin were reduced 6 mo after RYGB (P < 0.05). The consumption frequency of many foods defined as unhealthy decreased after surgery (e.g., from 15.4% to 5.1% for pizza and 18% to 0% for hamburger), and some healthy food increased (e.g., from 0% to 5.1% for fish and from 0% to 25.6% for plain yogurt). There was a decrease in the frequency of individuals who reported consuming fruit and vegetables. Conversely, insulin, glucose, and TG levels were positively associated with intake of chocolates/truffles and ice cream/sundaes. CONCLUSION: Participants in the present study appeared to develop a healthier dietary pattern by 6 mo after RYGB. These results show that a healthier dietary pattern is associated with a significant improvement of metabolic profile and weight loss.

Evaluation of Lean Body Weight Equation by Dual-Energy X-Ray Absorptiometry Measures.

BACKGROUND: When managing patients with disorders that require clinical intervention, a practical assessment of body habitus is valued. The Duffull-Green lean body weight (LBW) equation was derived and validated in adults across a wide body mass index (BMI) range. Whether this predictive equation will perform well in patients at BMI extremes or perform better than a widely used empiric "ideal" body weight (IBW) equation is unknown. MATERIALS AND METHODS: Calculated LBW and calculated IBW were each compared with the dual-energy x-ray absorptiometry (DXA)-derived lean body mass (LBM) by simple linear regression. A mixed model was used to determine how well the LBW equation performed over time in patients with more than 1 DXA measurement. RESULTS: At time 0, 32 patients were 18-67 years old, and all were obese (BMI: 36-65 kg/m2), while the remaining 7 had parenteral nutrition-dependent intestinal failure (BMI: 17-25 kg/m2). A subset of patients underwent bariatric surgery after time 0 (BMI at follow-up: 22-49 kg/m2). The LBW equation was a predictor of LBM ( R2 = 0.67, P < .0001), while the IBW equation was not ( R2 = 0.04, P = .25). The LBW equation remained a predictor of LBM over time ( P < .0001) without significant interaction by number of months since time 0. CONCLUSION: The Duffull-Green LBW equation successfully predicted lean body mass in a patient population with a wide range of BMIs at both a single point in time and after considerable weight loss. In the clinical setting, an equation that performs well in various disease states and body sizes is advantageous.

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.

Early effects of Roux-en-Y gastric bypass on peptides and hormones involved in the control of energy balance.

INTRODUCTION: Body weight varies depending on the prevailing direction of environmental pressures; however, physiological factors also play a significant role in the control of body weight. The aim of the present study was to assess the impact of Roux-en-Y gastric bypass (RYGB) on hormones and peptides involved in the control of energy balance and their possible implications in appetite/satiety. METHODS: The sample included 39 individuals with extreme obesity (37 women and two men) who underwent RYGB. Anthropometric and biochemical markers were collected before surgery and 6 months after RYGB. RESULTS: The BMI decreased from 44.3±6.4 to 31.7±5.7 kg/m (P<0.001) at the sixth month. Percentage of excess weight lost was 63.2±25.0%. Leptin and glucose levels decreased significantly 6 months after RYGB (P<0.001). Interestingly, a significant correlation was confirmed between the anorexigenic gut hormone peptide YY (PYY) and the central anorexigenic mediator α-melanocyte-stimulating hormone after 6 months of RYGB (r=0.35, P=0.004). In contrast, PYY concentrations were correlated negatively with BMI (r=-0.34, P=0.002). CONCLUSION: In the present investigation, it was found that there is a relationship between α-melanocyte-stimulating hormone and PYY concentrations, and it supports the role of the PYY to POMC signal in appetite regulation after RYGB.

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.

Roux-en-Y gastric bypass decreases pro-inflammatory and thrombotic biomarkers in individuals with extreme obesity.

BACKGROUND: The low-grade inflammatory state in obesity leads to insulin resistance and endothelial dysfunction, which promote cardiovascular diseases in individuals with obesity. The purpose of this study was to evaluate the early effects of weight loss achieved through bariatric surgery on the inflammatory and prothrombotic states. This study also aimed to identify the role of hyperleptinemia on the prothrombotic state. METHODS: The sample was composed of 41 extremely obese who underwent Roux-en-Y gastric bypass (RYGB). Anthropometric and clinical data, and biochemical markers of inflammation were collected prior to surgery and 6 months post-RYGB. RESULTS: It was found that plasminogen activator inhibitor-1 (PAI-1) concentrations were higher among extremely obese individuals with hyperleptinemia than in those without hyperleptinemia (p < 0.01).In relation to the baseline, post-surgery body mass index (BMI) was reduced by 12.9 kg/m(2), corresponding to 63.50 % of excess weight loss. Additionally, waist circumference was found to decrease significantly from 126.2 to 101.4 cm. Plasma total cholesterol (p < 0.01), LDL cholesterol (p = 0.02), triglycerides (p < 0.01), and glucose (p = 0.01) were also found to decrease. Pro-inflammatory biomarkers were observed to decrease: PAI-1 by 55.9 ± 6.0 % (p < 0.01), C-reactive protein (CRP) by 18.8 ± 3.4 % (p < 0.01), intercellular adhesion molecule-1 (ICAM-1) by 89.9 ± 5.7 % (p < 0.01), leptin by 27.9 ± 3.2 % (p < 0.01), and resistin by 69.3 ± 5.8 % (p < 0.01). Additionally, significant decreases of tumor necrosis factor alpha (TNF-α) and leptin/adiponectin ratio were observed. Anti-inflammatory cytokines adiponectin and interleukin-10 (IL-10) were significantly increased (170.7 ± 82.5 %, p < 0.01; 122.7 ± 55.1 %, p = 0.02). CRP levels were predictive of ICAM-1 (p = 0.04), and changes in leptin concentrations were associated with decreased PAI-1 levels (p = 0.03). CONCLUSIONS: We observed that individuals with obesity that have hyperleptinemia have higher circulating PAI-1 levels, which could indicate increased risk for cardiovascular disease. The biomarkers of inflammation and thrombosis measured in this study decreased after RYGB, suggesting that the surgery may be effective in reducing pro-inflammatory and thrombotic risk in individuals with extreme obesity.

Vitamin D status following bariatric surgery: implications and recommendations.

Individuals with extreme obesity who qualify for bariatric surgery are frequently vitamin D deficient before and after surgery. The anatomical changes that occur during some bariatric procedures may lead to decreased absorption of vitamin D, although vitamin D absorption and metabolism has not been quantified or compared across surgeries, and multiple other factors could influence vitamin D status in these individuals. Vitamin D treatment and dosing studies show that there is variability in how individuals respond to supplementation regimens regardless of the bariatric procedure. It is unknown if improving vitamin D status before and/or after bariatric surgery can affect health-related outcomes in this population beyond the traditional roles of vitamin D. Vitamin D has been purported to positively influence a variety of obesity-related comorbidities. Furthermore, in light of the potential role of vitamin D in immunity and inflammation, it seems important to consider the ramifications of vitamin D deficiency in the postbariatric individual in the critical care setting and particularly in the context of aging. Additional research is needed to develop evidence-based guidelines for optimal treatment of vitamin D deficiency in individuals before and after bariatric surgery and to determine the impact of vitamin D repletion on non-bone health-related outcomes in these individuals.

Validity of bioelectrical impedance analysis to assess fat-free mass in patients with head and neck cancer: an exploratory study.

BACKGROUND: The purpose of this study was to validate bioelectrical impedance analysis (BIA) using the Geneva equation for fat-free mass (FFM) in patients with head and neck cancer. METHODS: In 24 patients with head and neck cancer, agreement between BIA (FFMBIA ) and dual energy x-ray absorptiometry (FFMDXA ) 1 week before (T0 ), 1 month (T1 ), and 4 months (T2 ) after cancer treatment was analyzed. RESULTS: FFMBIA did not differ from FFMDXA (mean difference 0.71 ± 1.9, 0.30 ± 1.9, and 0.02 ± 2.1 kg) at any time point. Only at T0 , mean FFM correlated to the difference between FFMDXA and FFMBIA (r = 0.48; p = .017). Limits of agreement were 3.8, 3.7, and 4.1 kg, respectively. Concordance Correlation Coefficients were 0.98 at all time points. CONCLUSION: BIA may be used to assess FFM with reasonable validity based on mean-level comparisons, but differences between BIA and DXA may vary by about 4 kg in an individual patient. These results require confirmation in a larger sample of patients with head and neck cancer.

Serum 25(OH) vitamin D concentration changes after Roux-en-Y gastric bypass surgery.

OBJECTIVE: To describe serum 25(OH)D changes after Roux-en-Y gastric bypass (RYGB) and to determine if fat mass (FM) loss and vitamin D intake are associated with changes in serum levels. DESIGN AND METHODS: The relationship between serum 25(OH)D and 1) FM, 2) weight, 3) % excess weight loss (EWL), and 4) BMI was investigated after controlling for potential confounders using a mixed effects linear model in 20 women before and up to 1-year post-RYGB. Subcutaneous (SAT) and visceral adipose tissue (VAT) vitamin D concentrations at time of RYGB were also evaluated. RESULTS: Weight and FM decreased 1-year after surgery by 45 ± 1 kg and 37 ± 1 kg, respectively while 25(OH)D increased by 10 ± 2 ng mL(-1) . Weight, FM, BMI, and %EWL changes were associated with 25(OH)D change. VAT had an average 21% more vitamin D per gram than SAT and concentrations were highly correlated. CONCLUSIONS: Although weight loss may lead to increased serum 25(OH)D after RYGB, low levels remain a concern in some patients 1-year postsurgery. Additional research is needed to clarify the relationship between adipose storage of vitamin D and serum 25(OH)D in obesity, and how that relationship might change after surgery. This could lead to improved clinical management of vitamin D in this ever-growing clinical population.

Relevance of the new pre-cachexia and cachexia definitions for patients with rheumatoid arthritis.

BACKGROUND & AIMS: The recently proposed definitions of 'pre-cachexia' and 'cachexia' might offer new possibilities for the detection of malnutrition in patients with rheumatoid arthritis (RA). METHODS: The prevalence of different components of nutritional status and the compiled definitions of 'precachexia' and 'cachexia' were measured in a cohort of 103 patients with moderately active RA. Nutritional status was determined by measuring unintentional weight loss, BMI, and muscle strength. Bio-electrical Impedance Analysis (BIA) was used to determine fat free mass index (FFMI) and fat mass index. In addition, appetite, pain, fatigue, and inflammatory activity were assessed. The prevalence of 'pre-cachexia' and 'cachexia' was calculated from different combinations of these parameters. RESULTS: 20% of the study population had a low FFMI (<10th percentile), and 95% had a decreased muscle strength ( < lowest tertile). Weight loss and loss of appetite, both essential elements in the newly proposed (pre-)cachexia definitions, were uncommon. The prevalence of 'pre-cachexia' and 'cachexia' was both 1% (n = 1). CONCLUSIONS: In spite of altered body composition and impaired body function, the recently proposed definitions of both 'pre-cachexia' and 'cachexia' were unable to identify and diagnose impaired nutritional status in RA patients mainly because of low prevalences of weight loss and decreased appetite.

Changes in gastrointestinal hormones and leptin after Roux-en-Y gastric bypass surgery.

BACKGROUND: Roux-en-Y gastric bypass (RYGB) imparts long-term weight loss, the mechanisms for which are not well understood. Changes in leptin and gastrointestinal (GI) hormones, including glucagon-like peptide 1 (GLP-1), peptide YY (PYY), and ghrelin, may contribute to the relative success of RYGB compared with conventional weight loss methods. This study evaluated changes in GI hormones and leptin post-RYGB. The study also evaluated whether GI hormones differed after a short-term dose of protein or fat. METHODS: GLP-1, PYY, ghrelin, and leptin were assessed in 16 women before RYGB and up to 1 year after RYGB. Plasma was collected before and at several times after a short-term equicaloric dose of protein or fat. RESULTS: GLP-1 area under the curve (AUC) increased at week 6 and 1 year in the fat beverage (FAT-BEV) group compared with baseline. PYY AUC remained elevated at 1 year in the FAT-BEV group. Ghrelin AUC decreased at week 2, week 6, and 1 year in the protein beverage (PRO-BEV) group compared with baseline. Ghrelin AUC was lower in the PRO-BEV group compared with the FAT-BEV group at week 6. Fasted leptin decreased at all visits in both groups and was lower in the FAT-BEV group compared with the PRO-BEV group at 1 year. CONCLUSIONS: Changes from baseline were evident for all GI hormones and leptin; some differences were evident soon after surgery (ghrelin, leptin), whereas others were maintained long term (GLP-1, PYY, ghrelin, leptin). In response to a short-term stimulus, protein suppressed ghrelin and fat potently stimulated GLP-1 and PYY. Future work in this area is warranted.

Comparison of DXA and water measurements of body fat following gastric bypass surgery and a physiological model of body water, fat, and muscle composition.

Measurement of body composition changes following bariatric surgery is complicated because of the difficulty of measuring body fat in highly obese individuals that have increased photon absorption and are too large for the standard dual-energy X-ray absorptiometry (DXA) table. We reproducibly measured body composition from half-body DXA scans and compared the values of total body fat estimated from total body water (TBW) and DXA measurements before and after Roux-en-Y gastric bypass surgery (RYGB). DXA, TBW (deuterium dilution), extracellular water (ECW; bromide dilution), and intracellular water (ICW) measurement (by subtraction) were made before surgery and at 2 wk, 6 wk, 6 mo, and 12 mo after surgery. Twenty individuals completed baseline and at least four follow-up visits. DXA appeared to underestimate the fat and bone mass in extreme obesity (before surgery), whereas at 6 and 12 mo after surgery, the DXA and TBW fat measurements were similar. The ECW-to-ICW ratio was increased in obese individuals and increased slightly more after surgery. We describe a new model that explains this abnormal water composition in terms of the normal physiological changes that occur in body composition in obesity and weight loss. This model is also used to predict the muscle mass loss following RYGB.

Assessing validity and reliability of resting metabolic rate in six gas analysis systems.

The Deltatrac Metabolic Monitor (DTC) (VIASYS Healthcare Inc, SensorMedics, Yorba Linda, CA), one of the most popular indirect calorimetry systems for measuring resting metabolic rate (RMR) in human subjects, is no longer being manufactured. This study compared five different gas analysis systems to the DTC. RMR was measured by the DTC and at least one other instrument at three study sites for a total of 38 participants. The five indirect calorimetry systems included the MedGraphics CPX Ultima (Medical Graphics Corp, St Paul, MN), the MedGem (Microlife USA, Golden, CO), Vmax Encore 29 System (VIASYS Healthcare Inc, Yorba Linda, CA), the TrueOne 2400 (Parvo Medics, Sandy, UT), and the Korr ReeVue (Korr Medical Technologies, Salt Lake City, UT). Validity was assessed using paired t tests to compare means; reliability was assessed by using both paired t tests and root mean square calculations with F tests for significance. Within-subject comparisons for validity of RMR revealed a significant difference between the DTC and the Ultima system. Bland-Altman plot analysis showed significant bias with increasing RMR values for the Korr and MedGem systems. Respiratory exchange ratio (RER) analysis showed a significant difference between the DTC and the Ultima system and a trend for a difference with the Vmax system (P=0.09). Reliability assessment for RMR revealed that all instruments had a significantly larger coefficient of variation (CV) (ranging from 4.8% to 10.9%) for RMR compared to the 3.0% CV for the DTC. Reliability assessment for RER data showed none of the instrument CVs was significantly larger than the DTC CV. The results were quite disappointing because none of the instruments equaled the within-person reliability of the DTC. The TrueOne and Vmax systems were the most valid instruments in comparison with the DTC for both RMR and RER assessment. Further testing is needed to identify an instrument with the reliability and validity of the DTC.