Body composition: research and clinical advances--1993 A.S.P.E.N. research workshop

Systematic review: Sarcopenia in paediatric inflammatory bowel disease

BACKGROUND

Low skeletal muscle mass (MM) and deteriorated function (sarcopenia) can be a frequent complication in paediatric inflammatory bowel disease (IBD).

AIM

To conduct a systematic review of the paediatric IBD literature on skeletal muscle function and mass and identify interventions that could affect them.

METHODS

Systematic searches (EMBASE, Medline, Cochrane library central for registered control trials and Web of Science) were conducted using the terms 'lean body mass' (LM), 'fat free mass' (FFM) or 'MM' and 'IBD'.

RESULTS

Fourteenth studies were included, presenting data from 439 Crohn's disease (CD), 139 ulcerative colitis (UC) and 2 IBD-unclassified participants compared with healthy matched or unmatched groups or reference populations. Six out of 14 studies reported lower LM, whilst 7 studies observed lower MM and FFM in CD patients compared to healthy controls. Research in UC patients reported lower LM in 3 studies, lower MM in 3 studies and lower FFM in 4 studies. Three prospective studies measured the impact of enteral feeding and showed improvement on disease activity and LM or FFM, while one retrospective study did not show any impact on LM.

CONCLUSION

Despite the variety of experimental approaches and methods used to assess sarcopenia, most studies showed reduction in MM, LM and FFM in IBD. Nutritional intervention may have a positive effect on LM and FFM. Future research should focus on standardizing the terminology and methodologies used in assessing body composition and investigating sarcopenia in diseased and matched healthy control cohorts in adequately powered studies with a longitudinal design.

Body composition assessment using bioelectrical impedance analysis (BIA) in a wide cohort of patients affected with mild to severe obesity

BACKGROUND & AIMS

Obesity is characterized by fat mass excess (FM), extra cellular water increase (ECW) and, with ageing, decrease in fat free mass (FFM). The validity of body impedance analysis (BIA) in patients with mild to severe obesity is still debated. The purpose of this study is to describe the Resistance (Rz) and Reactance (Xc) values obtained by Body Impedance Analysis (BIA) in a wide cohort of Italian patients with mild to severe obesity. The secondary endpoint is to describe the resulting body composition values (as percentage and indexes) in this population.

METHODS

The study enrolled adult in-patients with mild to severe obesity (classified with class I, II and III obesity) undergoing clinical care rehabilitation program for obesity complications and weight loss. BIA values were grouped by sex, BMI and age classes.

RESULTS

A total of 8303 patients with obesity, aged 18 to 90 y, were studied. The Resistance (Rz) and Reactance (Xc) were reported by sex, age and BMI classes. In women and men both, the phase angle (PhA) decreases with increasing BMI (kg/m²) and the resulting BIA vector was significantly shifted. The FM index (FMI) was higher (p < 0.0001) in women while FFM index (FFMI) was higher in men (p < 0.0001) and significantly associated with BMI. FFMI decreased with age in both sex (p < 0.0001). Skeletal mass (SM) presents a progressive reduction in relation to age and gender both.

CONCLUSIONS

The present BIA-based body composition analysis in a wide cohort of mild to severe obese patients revealed a significantly decreased Rz and Xc values with a consequent significant decrease of PhA in a BMI-dependent manner. The body compartments estimation with available equations was BMI, sex and age dependent. These observational results could be the basis for the development of new equations adapted for patients suffering from obesity.

Impact of phase angle on postoperative prognosis in patients with gastrointestinal and hepatobiliary-pancreatic cancer

OBJECTIVE

Phase angle (PhA), by bioelectrical impedance analysis, has been used in patients with several diseases; however, its prognostic value in patients with gastrointestinal (GI) and hepatobiliary-pancreatic (HBP) cancer is unclear. The aim of the present study was to investigate the effects of PhA on postoperative short- outcomes and long-term survival in these patients.

METHODS

This retrospective study reviewed data from 501 patients with GI and HBP cancers who underwent first resection surgery. The data were divided into the following groups according to the preoperative PhA quartile values by sex: high-PhA group with the highest quartile (Q4), normal-PhA group with middle quartiles (Q3 and Q2), and low-PhA group with the lowest quartile (Q1). Preoperative nutritional statuses, postoperative short-term outcomes during hospitalization, and 5-y survival between three groups were compared. Cox proportional hazard models were used to evaluate the prognostic effect of PhA.

RESULTS

PhA positively correlated with body weight, skeletal muscle mass, and handgrip strength, and negatively correlated with age and levels of C-reactive protein. The low-PhA group showed a higher prevalence of malnutrition (48%) than normal-PhA (25%), and high-PhA groups (9%; P < 0.001). The incidence of postoperative severe complications was 10% for all patients (14% in low-PhA, 12% in normal-PhA, and 4% in high-PhA; P = 0.018). The incidence of prolonged stays in a postoperative high-care or intensive care unit was 8% in all patients (16% in low-PhA, 8% in normal-PhA, and 2% in high-PhA; P < 0.001). The 5-y survival rate was 74% in all patients (68% in low-PhA, 74% in normal-PhA, and 79% in high-PhA; P < 0.001). The multivariate analysis demonstrated that a low-PhA group was an independent risk factor for mortality (hazard ratio, 1.99; 95% confidence interval, 1.05-3.90; P = 0.034).

CONCLUSION

PhA is a useful short-term and long-term postoperative prognostic marker for patients with GI and HBP cancers.

Bioelectrical Impedance Analysis and Dual Energy X-Ray Absorptiometry to Monitor Nutritional Status

There exists an imperative to monitor changes in body composition in all dialysis patients on a regular basis to avoid overt malnutrition. In this regard, the absolute measurement of the fat-free mass assessment may not be as crucial as the serial measurement of fat-free mass with the same modality. A significant difference in measured fat and fat-free mass should be expected if different techniques are employed. Therefore, when attempting to monitor patients over time or to assess the effects of changes in therapeutic regimens, a single methodology should be employed. Our data validate the use of BIA in the stable PD patient, indicating that BIA can predict the DXA results. Considering the ease with which

BIA measurements can be obtained and the lack of dependency on operator interpretation, BIA is an ideal technique for use in the clinical setting. The applicability of this technique for use in monitoring longitudinal changes in body composition has, in fact, been well established (25,30,31). BIA appears to be an excellent method for routine fat-free mass measurement in dialysis patients. In as much as malnutrition continues to remain a significant problem in PD patients, measuring and monitoring body composition is strongly recommended.

Getting to grips with sarcopenia: recent advances and practical management for the gastroenterologist

Sarcopenia is a progressive and generalised disorder of skeletal muscle strength, function and mass, that is most commonly associated with the normal ageing process. It is increasingly recognised that sarcopenia can also develop as a consequence of malabsorptive and inflammatory conditions, such as those seen by gastroenterologists and hepatologists. It affects 1%-30% of the general population, but is seen in approximately 40% of patients with gastrointestinal conditions including inflammatory bowel disease and cirrhosis. Within this group of patients, it is associated with increased complications and mortality. The pathogenesis of sarcopenia is multifactorial with several risk factors implicated in its development including undernutrition, physical inactivity and coexistent multimorbidity. The SARC-F questionnaire has been developed to screen for patients at risk of sarcopenia, however, this focuses on the functional consequences and will therefore not identify those patients who are early in the progression of sarcopenia. There are several different non-invasive techniques available to assess muscle quantity and quality including; grip strength, dual energy X-ray absorptiometry, CT which can be used together to diagnose sarcopenia. Assessment and correction of malnutrition, particularly protein intake, in those at risk of sarcopenia is important in preventing the development and progression of sarcopenia. There are no specific drugs that are available for the treatment of sarcopenia, however, resistance exercise programmes combined with nutritional interventions show promise. It is important that this common condition is screened for and recognised, with any contributing factors addressed to reduce the risk of its progression.

Survival and CT defined sarcopenia in patients with intestinal failure on home parenteral support

BACKGROUND & AIMS

Sarcopenia occurs in patients with intestinal failure (IF) and has been associated with poorer survival in several chronic diseases. CT can measure sarcopenia through a L3 skeletal muscle index (LSMI). We aim to describe the prevalence of sarcopenia in a section of our IF population using LSMI, & evaluate the effect of home parenteral support (PS) on LSMI & survival. Additionally, we aim to assess any association between LSMI, BMI & other anthropometric measurements.

METHODS

IF patients on PS treated at St Mark's Hospital between 1/1/2006-1/10/2016 were identified from a prospectively maintained database. Patients were included if they were on PS & had 2 CTs: the first ≤30 days before start of HPN (pre-PS); the second ≥100 days from PS start (post-PS). Patient records were reviewed to obtain clinical & demographic information & date of death. Anthropometric measurements & BMI contemporaneous to CT scans were recorded.

RESULTS

64 patients met inclusion criteria (M:F 1:1). 83% of our cohort had LSMI below previously published thresholds for sarcopenia. Mean (SD) pre-PS LSMI was 36.5 (6.8)cm²/m². Mean BMI pre-PS was 22.1 (4.8) kg/m². Both BMI (22.1 kg/m² to 23.5 kg/m²) p < 0.001) & LSMI (36.5 cm²/m² to 38.4 cm²/m²) (p = 0.003) increased post-PS. A positive correlation was seen between BMI & LSMI pre (r = 0.47 p < 0.001) & post-PS (r = 0.37 p = 0.003). No correlation was seen between LSMI & anthropometric measurements pre-PS (p = 0.78) or post-PS (p = 0.96). 11 (17%) patients died during the study period; a low LSMI pre-PS was not a risk factor for mortality (HR 0.97 p = 0.55).

CONCLUSIONS

This study is the first to look at sarcopenia & survival using CT defined LSMI (CT-LSMI) in the IF population. 83% of our cohort had a pre-PS LSMI below previously published thresholds, yet we found no relationship between lower baseline LSMI & survival. This may reflect the heterogeneity of the prognoses of the IF population, or that parenteral nutrition itself affects survival. Our study showed that LSMI & BMI improved following PS but demonstrated that other anthropometric measurements had poor correlation with LSMI & showed no significant improvement overall after PS, confirming the known problems of inter-operator & patient variability of these measurements. Whilst we found significant correlation between LSMI & BMI, BMI significantly underestimated the presence & degree of sarcopenia. LSMI has the potential to provide an objective & reproducible measure of sarcopenia in IF. Future larger studies should be performed to evaluate associations with patient outcomes & utility in clinical decision making.

Tolerance and physiological correlates of neuromuscular electrical stimulation in COPD: a pilot study

Rationale

Neuromuscular electrical stimulation (NMES) of the lower limbs is an emerging training strategy in patients with COPD. The efficacy of this technique is related to the intensity of the stimulation that is applied during the training sessions. However, little is known about tolerance to stimulation current intensity and physiological factors that could determine it. Our goal was to find potential physiological predictors of the tolerance to increasing NMES stimulation intensity in patients with mild to severe COPD.

Methods

20 patients with COPD (FEV₁ = 54±14% pred.) completed 2 supervised NMES sessions followed by 5 self-directed sessions at home and one final supervised session. NMES was applied simultaneously to both quadriceps for 45 minutes, at a stimulation frequency of 50 Hz. Spirometry, body composition, muscle function and aerobic capacity were assessed at baseline. Cardiorespiratory responses, leg discomfort, muscle fatigue and markers of systemic inflammation were assessed during or after the last NMES session. Tolerance to NMES was quantified as the increase in current intensity from the initial to the final NMES session (ΔInt).

Results

Mean ΔInt was 12±10 mA. FEV₁, fat-free-mass, quadriceps strength, aerobic capacity and leg discomfort during the last NMES session positively correlated with ΔInt (r = 0.42 to 0.64, all p≤0.06) while post/pre NMES IL-6 ratio negatively correlated with ΔInt (r = −0.57, p = 0.001). FEV₁, leg discomfort during last NMES session and post/pre IL-6 ratio to NMES were independent factors of variance in ΔInt (r² = 0.72, p = 0.001).

Conclusion

Lower tolerance to NMES was associated with increasing airflow obstruction, low tolerance to leg discomfort during NMES and the magnitude of the IL-6 response after NMES.

Trial Registration

ClinicalTrials.gov NCT00809120

A comparison of prediction equations for the estimation of body fat percentage in non-obese and obese older Caucasian adults in the United States

OBJECTIVES

The predictive capabilities of skinfold regression equations are limited across populations and current equations may not be well suited for the prediction of body fat in older adults or obese Americans. The goal of this study was to compare percent body fat (%BF) predicted by several skinfold regression equations to %BF determined by Dual-Energy X-ray Absorptiometry (DXA) in obese and non-obese Caucasian men and women in the United States over the age of 65 years.

DESIGN

A block design was used with two blocks: obesity (non-obese/obese) and gender (male/female). All subjects underwent the same testing procedures in one visit.

SETTING

University of Pittsburgh Clinical and Translation Research Center.

PARTICIPANTS

Seventy-eight older healthy adults were recruited for participation.

MEASUREMENTS

Actual percent body fat was determined from a whole body DXA scan. Estimated percent body fat (%BF) was calculated using skinfold measurements and established regression equations. The predictive accuracy of the regression equations was evaluated by comparing the estimated %BF to the actual %BF measured with DXA using a within subject ANOVA (α=0.05). This was done within subgroups: obese males, obese females, non-obese males and non-obese females.

RESULTS

Durnin and Womersly and Jackson and Pollock had reasonably good agreement with DXA in older Caucasian American females and males, respectively. The remaining equations significantly overestimated %BF in older Caucasian American males. Mixed results were found in females with Gause-Nilsson and Jackson and Pollock significantly underestimating %BF, while Visser and Kwok overestimated %BF.

CONCLUSION

Numerous factors of a population including age, race, ethnicity, gender and obesity should be considered when selecting a skinfold regression equation to estimate %BF. While Durnin and Womersly and Jackson and Pollock are recommended for predicting %BF in older Caucasian American females and males, respectively, there exists a need to develop accurate regression models that consider obesity, gender, race or ethnicity when predicting %BF in a diverse geriatric American population.

[Body composition: assessment and clinical value]

Obesity control and prevention is a complex task that requires a thorough understanding of the physiological basis and body composition. In Spain, as in most countries, anthropometric criteria, such as weight, height, body mass index, skinfold thickness and body circumferences have traditionally been used to define obesity and general eating disorders, but these variables have little sensitivity for monitoring response to treatment. This is why evaluation of body composition may qualify this process. The aim of this paper was to review some relatively simple techniques to assess body composition and their clinical value in patients.

Satellite cells senescence in limb muscle of severe patients with COPD

RATIONALE

The maintenance of peripheral muscle mass may be compromised in chronic obstructive pulmonary disease (COPD) due to premature cellular senescence and exhaustion of the regenerative potential of the muscles.

METHODS

Vastus lateralis biopsies were obtained from patients with COPD (n = 16) and healthy subjects (n = 7). Satellite cell number and the proportion of central nuclei, as a marker of muscle regenerative events, were assessed on cryosections. Telomere lengths, used as a marker of cellular senescence, were determined using Southern blot analyses.

RESULTS

Central nuclei proportion was significantly higher in patients with COPD with a preserved muscle mass compared to controls and patients with COPD with muscle atrophy (p<0.001). In COPD, maximal telomere length was significantly decreased compared to controls (p<0.05). Similarly, minimal telomere length was significantly reduced in GOLD III-IV patients with muscle atrophy compared to controls (p<0.005). Minimal, mean and maximum telomere lengths correlated with mid-thigh muscle cross-sectional area (MTCSA) (R = 0.523, p = 0.005; R = 0.435, p = 0.019 and R = 0.491, p = 0.009, respectively).

CONCLUSIONS

Evidence of increased regenerative events was seen in GOLD III-IV patients with preserved muscle mass. Shortening of telomeres in GOLD III-IV patients with muscle atrophy is consistent with an increased number of senescent satellite cells and an exhausted muscle regenerative capacity, compromising the maintenance of muscle mass in these individuals.

Distribution and determinants of adiponectin, resistin and ghrelin in a randomly selected healthy population

OBJECTIVE

Adiponectin, resistin, ghrelin and the IGF-I system seem to play an important role in the regulation of body composition throughout life, but the mechanisms are not well understood. The aim of our study was to analyse the distribution among sexes and all decades of the adult life of adiponectin, resistin and ghrelin and their relationship with anthropometric, body composition parameters and the IGF-I system.

SUBJECTS

One hundred and thirty-four men and 127 healthy women were included in the study.

MEASUREMENTS

Plasma concentration of adiponectin, resistin, ghrelin, total IGF-I, free IGF-I and IGFBP-3 were determined in all subjects. Body composition was evaluated by bioelectrical impedance.

RESULTS

Resistin and ghrelin were not affected by age. Plasma adiponectin correlated negatively with age, body mass index (BMI), waist-to-hip ratio (WHR), waist circumference (WC), fat mass (FM) and body fat (BF) in men. Adiponectin correlated negatively with WHR and positively with free IGF-I in women. Resistin correlated positively with BMI and WC only in men, and ghrelin correlated positively with WC, BMI and FM and negatively with free IGF-I in men. In multiple regression analysis adiponectin remained associated with WHR (beta=-0.19, P=0.01) in women. Resistin was positively associated with BMI (beta=0.30, P=0.003) in women and ghrelin was negatively related to free IGF-I (beta=-0.158, P=0.019) in men.

CONCLUSIONS

Plasma adiponectin declines with age and is negatively associated with FM in men. Our data suggest the existence of a positive correlation of adiponectin and the IGF-I axis in women and of an inverse relationship between ghrelin and the IGF-I system in men.

Bioelectrical impedance analysis: population reference values for phase angle by age and sex

BACKGROUND

Phase angle is an indicator based on reactance and resistance obtained from bioelectrical impedance analysis (BIA). Although its biological meaning is still not clear, phase angle appears to have an important prognostic role.

OBJECTIVE

The aim of this study was to estimate population averages and SDs of phase angle that can be used as reference values.

DESIGN

BIA and other methods used to evaluate body composition, including hydrodensitometry and total body water, were completed in 1967 healthy adults aged 18-94 y. Phase angle was calculated directly from body resistance and reactance, and fat mass (FM) was estimated from the combination of weight, hydrodensitometry, and total body water by using the 3-compartment Siri equation. Phase angle values were compared across categories of sex, age, body mass index (BMI), and percentage FM.

RESULTS

Phase angle was significantly (P < 0.001) smaller in women than in men and was lower with greater age (P < 0.001). Phase angle increased with an increase in BMI and was significantly inversely associated with percentage fat in men. Phase angle was significantly predicted from sex, age, BMI, and percentage FM in multiple regression models.

CONCLUSIONS

Phase angle differs across categories of sex, age, BMI, and percentage fat. These reference values can serve as a basis for phase angle evaluations in the clinical setting.

The IGF-I system component concentrations that decrease with ageing are lower in obesity in relationship to body mass index and body fat

The aim of this study was to investigate the GH-IGF-I axis in healthy adults and its relationship to obesity. We studied 268 subjects: 134 men and 134 women, and determined anthropometric and body composition variables. Serum total IGF-I was measured by radioimmunoassay, serum free IGF-I concentrations by enzyme linked immunosorbant assay and serum IGFBP3 concentrations by radioimmunoassay. In men, we observed a decrease in total IGF-I, free IGF-I and IGFBP-3 throughout decades. In women, the body mass index and fat mass were higher throughout decades, and we observed a similar decrease to that in men in total IGF-I, free IGF-I and IGFBP3. In men with obesity, as measured by body fat, free IGF-I concentrations were lower than those without obesity; in women with obesity, total IGF-I concentrations and free IGF-I concentrations were lower than in those with obesity. These changes were observed in relationship to obesity when the subjects were adjusted for differences in age. We showed that in controls randomly selected, the GH-IGF-I axis component concentrations that decrease with increasing age are lower in obesity, especially in women, and that this decrease is related to body mass index and body fat.

Can bioelectrical impedance analysis identify malnutrition in preoperative nutrition assessment?

OBJECTIVE

Malnutrition is characterized by changes in cellular membrane integrity and alterations in fluid balance, both of which can be detected by bioelectrical impedance analysis (BIA). We investigated whether BIA-measured variables could detect malnutrition, as defined by the Subjective Global Assessment (SGA), in preoperative surgical patients.

METHODS

We prospectively evaluated 279 patients hospitalized for elective gastrointestinal surgery during the first 72 h after admission. BIA estimates were used to derive body cell mass, ratio of extracellular mass to body cell mass, and phase angle. Malnutrition diagnosed with these measures was compared with the SGA score. Receiver operating characteristic curves also were formulated to explore alternative cutoff points for one measure, phase angle.

RESULTS

A linear trend for means across SGA categories was found for all indicators used, except percentage of body cell mass. However, there was only fair overall agreement between SGA and BIA estimates. The receiver operating characteristic curves for phase angle suggested that the test was too sensitive or too specific. No alternative cutoff points resulted in suitable tests that could provide an alternative to SGA.

CONCLUSIONS

Although not in close agreement with SGA, the results suggested that there are some alterations in tissue electrical properties with malnutrition that can be detected by BIA. New cutoff points may be needed for application of BIA as a complementary method in the nutrition assessment of surgical patients.

Case study of the clinical usefulness of bioelectrical impedance spectroscopy in evaluating nutritional status

Bioelectrical impedance spectroscopy (BIS) can be a valuable tool in assessing changes in body composition. Although the validity of BIS in healthy subjects is relatively good, in patients considerably larger measurement errors have been reported. In this article the clinical usefulness of BIS in assessing nutritional status of one case study will be discussed. Interpretation of the predictions of BIS in this unstable patient was difficult. This is in agreement with the consensus that BIS does not give accurate prediction of body composition in individual patients. It is recommended that validation studies of BIS should focus on clinical aspects which can influence BIS measurements.

Hydration of fat-free body mass: review and critique of a classic body-composition constant

The assumed "constancy" of fat-free body mass hydration is a cornerstone in the body-composition research field. Hydration, the observed ratio of total body water to fat-free body mass, is stable at approximately 0.73 in mammals and this constancy provides a means of estimating total body fat in vivo. This review examines both in vitro and in vivo data that support the hydration constancy hypothesis and provides a critique of applied methodology. Biological topics of interest are then examined and critical areas in need of future research are identified. These are important issues because water dilution is the only method currently available for estimating body fat in all mammals, which range in body mass by a factor of 10(4).

The role of radiologic methods in assessing body composition and related metabolic parameters

The measurement of body composition and related metabolic parameters has become an important issue in clinical nutrition. Numerous techniques to assess visceral fat, which is strongly associated with metabolic disorders, have been developed. Other techniques focus mainly on the measurement of specific body components related to metabolic disturbances. This paper reviews methods that directly assess body composition and associated metabolic parameters. The principles of these methods and their accuracy, reproducibility and safety, as well as the clinical implications of their use, are discussed. Recent studies have documented the safety and efficacy of radiologic methods of assessing visceral fat, muscle mass, and morphology to obtain body composition data related to metabolic disturbances. Because these techniques have been documented to be safe and effective, clinicians should consider using them in the evaluation and follow-up of patients with various conditions.