Showing papers on "Body water published in 2009"
TL;DR: Examination of body composition adds information to an overall picture of nutrition of the elderly, since the body is not a simple two-compartment system and the concept of body cell mass would provide a better estimate than lean body mass of metabolically active tissue.
Abstract: he changes in composition of the aging T human body is of both gerontologic and geriatric interest and reflects genetic factors and environmental factors such as physical activity, nutrition, and disease, as well as the normal aging processes. In the study of normal aging, that is, aging per se, long-term trends in body compartments are important. In the field of clinical geriatrics, body composition is also of great interest in the study of obesity, malignant disease, and clinical pharmacology and biochemistry. Changes of body cell mass, body fat, and body water occur frequently in both disease and aging. These changes in body compartments may alter the pharmacokinetic and pharmacodynamic properties of drugs used in old age. The amount of body fat and the amount of body cell mass are important parameters when judging the net effect of energy intake and expenditure. Thus, examination of body composition adds information to an overall picture of nutrition of the elderly. Such overall knowledge also requires data on actual dietary habits of elderly populations in different countries. Not only intakes of energy, nutrients, and food items are important, but also distribution and composition data on meals and data on medical, psychologic, and socioeconomic conditions are prerequisites for the analysis of the relationship between requirements and actual intake. The need for broad epidemiologic approaches to these questions is obvious. Concepts The frequently used concept of “lean body mass” has two meanings, namely, body weight minus neutral fat, but including some lipids such as phospholipids, the exact amount of which is unknown. Lean body mass is, according to this meaning, similar to, but not identical with, fat-free body mass. Although lean body mass has a relatively constant specific gravity, from a biologic point of view it is a heterogenous body component with varying energy consumption, since it also comprises-apart from body cel I massfat-f ree ext race1 I u lar solids and extracellular water. Furthermore, since the water content of adipose tissue may show great variation and is also difficult to estimate, the definition of lean body mass should be body weight minus body fat, that is, fat-free mass. Many workers, nowadays, however, avoid the concept of a lean body mass and fat-free mass, since the body is not a simple two-compartment system. Moore and collaborators’ many years ago suggested that the concept of body cell mass would provide a better estimate than lean body mass of metabolically active tissue. Many workers now prefer to divide body weight into body cell mass, extracellular water, body fat, and fat-free extracellular solids that are present primarily in bone and connective tissuea2 For a review of the concepts of body compartments, see references 1, 3, 4, and 5.
268 citations
TL;DR: With increasing clinical uses of bioelectrical impedance in individuals and sample populations, the use of multiple-frequency impedance may help to elucidate differences that are not discernible with single- frequency impedance.
Abstract: Single-frequency bioelectrical impedance analyzers used to assess body composition are being replaced by multiple-frequency analyzers. At low frequencies, the current flows primarily through extracellular fluids; at high frequencies, it completely penetrates all body tissues. Measures of bioelectrical impedance at multiple frequencies can differentiate total and extracellular fluid compartments in the body. This has considerable value for assessing clinical and nutritional status. Impedance measures at a single frequency contain only a small window of the available impedance spectrum information, which may explain the difficulty in discriminating among individuals. The impedance spectrum and its analysis may provide a much clearer picture of individual differences in body water and body composition. With increasing clinical uses of bioelectrical impedance in individuals and sample populations, the use of multiple-frequency impedance may help to elucidate differences that are not discernible with single-frequency impedance.
188 citations
TL;DR: DXA provided cross‐sectional %BF data for obese adults without bias, however, individual data are associated with large prediction errors indicating that the DXA device used may not be able to accurately account for beam hardening in obese cohorts.
Abstract: The aim of this study was to determine the accuracy of dual-energy X-ray absorptiometry (DXA)-derived percentage fat estimates in obese adults by using four-compartment (4C) values as criterion measures. Differences between methods were also investigated in relation to the influence of fat-free mass (FFM) hydration and various anthropometric measurements. Six women and eight men (age 22-54 years, BMI 28.7-39.9 kg/m(2), 4C percent body fat (%BF) 31.3-52.6%) had relative body fat (%BF) determined via DXA and a 4C method that incorporated measures of body density (BD), total body water (TBW), and bone mineral mass (BMM) via underwater weighing, deuterium dilution, and DXA, respectively. Anthropometric measurements were also undertaken: height, waist and gluteal girth, and anterior-posterior (A-P) chest depth. Values for both methods were significantly correlated (r(2) = 0.894) and no significant difference (P = 0.57) was detected between the means (DXA = 41.1%BF, 4C = 41.5%BF). The slope and intercept for the regression line were not significantly different (P > 0.05) from 1 and 0, respectively. Although both methods were significantly correlated, intraindividual differences between the methods were sizable (4C-DXA, range = -3.04 to 4.01%BF) and significantly correlated with tissue thickness (chest depth) or most surrogates of tissue thickness (body mass, BMI, waist girth) but not FFM hydration and gluteal girth. DXA provided cross-sectional %BF data for obese adults without bias. However, individual data are associated with large prediction errors (+/-4.2%BF). This error appears to be associated with tissue thickness indicating that the DXA device used may not be able to accurately account for beam hardening in obese cohorts.
114 citations
TL;DR: Measuring pre- to post-exercise ΔBM is an accurate and reliable method to assess the ΔTBW, and the intraclass correlation coefficient was 0.76, indicative of excellent reliability between methods.
Abstract: This study tested the hypothesis that the change in body mass (ΔBM) accurately reflects the change in total body water (ΔTBW) after prolonged exercise. Subjects (4 men, 4 women; 22–36 year; 66 ± 10 kg) completed 2 h of interval running (70% VO2max) in the heat (30°C), followed by a run to exhaustion (85% VO2max), and then sat for a 1 h recovery period. During exercise and recovery, subjects drank fluid or no fluid to maintain their BM, increase BM by 2%, or decrease BM by 2 or 4% in separate trials. Pre- and post-experiment TBW were determined using the deuterium oxide (D2O) dilution technique and corrected for D2O lost in urine, sweat, breath vapor, and nonaqueous hydrogen exchange. The average difference between ΔBM and ΔTBW was 0.07 ± 1.07 kg (paired t test, P = 0.29). The slope and intercept of the relation between ΔBM and ΔTBW were not significantly different from 1 and 0, respectively. The intraclass correlation coefficient between ΔBM and ΔTBW was 0.76, which is indicative of excellent reliability between methods. Measuring pre- to post-exercise ΔBM is an accurate and reliable method to assess the ΔTBW.
108 citations
TL;DR: BMD is generally increased in acromegaly, though the anabolic effect of GH excess on bone is reduced, if not negated, by the presence of hypogonadism, particularly with regard to the trabecular compartment.
Abstract: Acromegaly is a condition characterized by growth hormone (GH) and insulin-like growth factor-1 (IGF-1) hypersecretion, and is associated with boney overgrowth, and soft tissue abnormalities due to anabolic, lipolytic, and sodium retaining actions of GH. GH and IGF-1 excess is associated with alterations in body composition, including an increase in body water and lean body mass, and a reduction in body fat. Achievement of biochemical control of the disease results in a reduction in body water and fat-free mass, and an increase in body fat. BMD is generally increased in acromegaly, though the anabolic effect of GH excess on bone is reduced, if not negated, by the presence of hypogonadism, particularly with regard to the trabecular compartment. Further studies are necessary to determine the effect of long-term biochemical control on bone density in subjects with acromegaly.
69 citations
TL;DR: Patients were more likely to have an expanded extracellular fluid volume if they had reduced daily fluid losses, but also with biomarkers typically associated with poor nutrition and inflammation.
Abstract: Background and Aims: Patients treated by peritoneal dialysis, especially those using automatic cyclers, are frequently found to be hypervolemic. To determine whether there are significant differences between the currently available modalities of peritoneal dialysis, we analyzed whether differences in transporter status and treatment modality had a discernible effect on extracellular fluid volumes as measured by multi-frequency bioimpedance. Methods: Two hundred prevalent peritoneal dialysis patients, 48% male, mean age 54.9 yr (SD±15.6), were studied using multi-frequency bioimpedance following a standard peritoneal equilibration test; 63 patients were treated by CAPD, 29 by APD, 96 by CCPD and 12 by OCCPD. Results: There were no differences in extracellular volumes, or extracellular volume adjusted for height, or as a ratio to total body water between the groups. As expected, extracellular volume adjusted for height depended upon bodyweight (r=0.412, p<0.001), sex (r=0.457, p<0.001) and systolic blood pressure (r=0.162, p=0.023), and extracellular volume to total body water related to the reciprocal of total daily peritoneal ultrafiltration losses (r=-0.0254, p=0.003) and urine output (-0.254, p=0.003). More importantly, on logistical regression analysis the ratio of extracellular fluid to total body fluid increased with falling albumin, F=21.5 p<0.001, increasing age, F= 1 8. 5 p<0.001, urine output F=6.46, p=0.014, total daily ultrafiltration, F=3.52 and protein intake p=0.003. Extracellular fluid adjusted for total body fluid was associated with CRP (males F=6.03, p=0.03, females F=4.438, p=0.04). Conclusion: Patients were more likely to have an expanded extracellular fluid volume if they had reduced daily fluid losses, but also with biomarkers typically associated with poor nutrition and inflammation.
59 citations
TL;DR: The focus of the present review is to recognize the different body fluid compartments, to clinically assess the degree of dehydration, to know how the equilibrium between extracellular fluid and intracellular fluid is maintained, and to calculate the effective blood osmolality.
Abstract: There is a high frequency of diarrhea and vomiting in childhood. As a consequence the focus of the present review is to recognize the different body fluid compartments, to clinically assess the degree of dehydration, to know how the equilibrium between extracellular fluid and intracellular fluid is maintained, to calculate the effective blood osmolality and discuss both parenteral fluid requirments and repair.
54 citations
TL;DR: The authors' athletes seem to have been relatively overhydrated and dehydrated during the race, as evidenced by the increased total body water and the fact that plasma sodium and hematocrit were lower postrace than prerace.
Abstract: We investigated whether ultraendurance runners in a 100-km run suffer a decrease of body mass and whether this loss consists of fat mass, skeletal muscle mass, or total body water. Male ultrarunners were measured pre- and postrace to determine body mass, fat mass, and skeletal muscle mass by using the anthropometric method. In addition, bioelectrical impedance analysis was used to determine total body water, and urinary (urinary specific gravity) and hematological parameters (hematocrit and plasma sodium) were measured in order to determine hydration status. Body mass decreased by 1.6 kg (p < .01), fat mass by 0.4 kg (p < .01), and skeletal muscle mass by 0.7 kg (p < .01), whereas total body water increased by 0.8 L (p < .05). Hematocrit and plasma sodium decreased significantly (p < .01), whereas plasma urea and urinary specific gravity (USG) increased significantly (p < .01). The decrease of 2.2% body mass and a USG of 1.020 refer to a minimal dehydration. Our athletes seem to have been relatively overhydrated (increase in total body water and plasma sodium) and dehydrated (decrease in body mass and increase in USG) during the race, as evidenced by the increased total body water and the fact that plasma sodium and hematocrit were lower postrace than prerace. The change of body mass was associated with the change of total body water (p < .05), and we presume the development of.
48 citations
TL;DR: Combined near-patient measurements of absolute and BIA-estimated TBW are achievable in a dialysis facility by identifying changes in body composition not fully appreciated by routine assessment and resulting in reduced sensitivity to longitudinal increases during a 12-mo period.
Abstract: Background and objectives: The feasibility and additional value of combining bioimpedance analysis (BIA) with near-subject absolute measurement of total body water using deuterium dilution (TBWD) in determining longitudinal fluid status was investigated.
Design, setting, participants, & measurements: Fifty-nine hemodialysis patients (17 female; age 58.4 ± 16.1 yr; body mass index 27.0 ± 5.4) were enrolled into a 12-mo, two-center, prospective cohort study. Deuterium concentration was measured in breath by flowing-afterglow mass spectrometry using a validated protocol ensuring full equilibration with the TBW; BIA was measured using a multifrequency, multisegmental device. Comorbidity was quantified by the Stoke score. Clinicians were blinded to body composition data.
Results: At baseline and 12 mo, there was an incremental discrepancy between TBWBIA and TBWD volumes such that greater comorbidity was associated with increasing overhydration. Forty-three patients who completed the study had no longitudinal differences in the prescribed or achieved postdialysis weights. In contrast, TBWD increased without a change in TBWBIA (mean difference −0.10 L). Changes in TBW and lean body mass differed according to baseline comorbidity; without comorbidity, BIA also identified an increase in TBW and lean body mass, whereas with increasing comorbid burden, BIA failed to demonstrate increases in tissue hydration identified by TBWD.
Conclusions: Combined near-patient measurements of absolute and BIA-estimated TBW are achievable in a dialysis facility by identifying changes in body composition not fully appreciated by routine assessment. BIA underestimates tissue overhydration that is associated with comorbidity, resulting in reduced sensitivity to longitudinal increases during a 12-mo period.
48 citations
TL;DR: The kidney volume measured by using multi-detector computed tomography is correlated well with body parameters, and is useful to predict renal function.
Abstract: 3; and mean kidney length was 10.80 ± 0.69 cm. The former correlated significantly with height, body weight, body-surface area, and total body water (p < 0.05, correlation coefficient : γ = 0.328, 0.649, 0.640, and 0.638, respectively). The latter also correlated significantly with all body indexes, however the correlation was weaker, except with height (p < 0.05, correlation coefficient : γ = 0.457, 0.473, 0.505, and 0.503, respectively). Only kidney volume significantly predicted estimated GFR (adjusted R 2 = 0.431, F = 85.90 and p < 0.05). Conclusion: The kidney volume measured with MDCT is correlated well with body parameters, and is useful to predict renal function.
45 citations
TL;DR: Twenty minutes after drinking, %BF estimates increased approximately 1.0% due to elevations in impedance and body mass, and adhering to the pretest fluid restriction guideline is recommended to avoid fluid-induced alterations in SBIA body composition measures.
Abstract: The effect of acute fluid consumption on measures of impedance and percent body fat estimated using segmental bioelectrical impedance analysis
TL;DR: Investigating body composition during a high-altitude expedition by using non-empirically derived methods, experimentally manipulating energy intake, and investigating the influence of initial body composition found high-ALTitude exposure decreased body mass, including the functionally important residual component.
TL;DR: Net PET ultrafiltration volume in routine clinical practice was not affected by CRP, hyperglycemia, or extracellular fluid volume overload and was increased in those patients with reduced serum sodium and albumin, most likely because of inflammation and protein malnutrition.
Abstract: Background and objectives: The peritoneal equilibration test (PET) was developed some 25 yr ago and has been used to help prescribe peritoneal dialysis. However, PET is affected by several factors, including diabetes and inflammation. It was speculated that extracellular fluid overload would increase PET ultrafiltration volumes, and therefore the usefulness of the PET in routine clinical practice was audited. Design, setting, participants, & measurements: Data from 211 consecutive patients attending a university teaching hospital for a standard PET who had multifrequency bioimpedance performance were analyzed to determine which factors affected net PET ultrafiltration volumes. Results: Net PET ultrafiltration volume was independent of gender, age, diabetes, residual renal function, peritoneal dialysis prescriptions (modes and dialysates), extracellular fluid volume, or C-reactive protein (CRP). There was an inverse regression with serum albumin and sodium on multiple logistical regression analysis (F = 13.4, P Conclusions: It was found that PET test ultrafiltration volume in routine clinical practice was not affected by CRP, hyperglycemia, or extracellular fluid volume overload. Ultrafiltration volumes were increased in those patients with reduced serum sodium and albumin, most likely because of inflammation and protein malnutrition.
TL;DR: The objectives of this substudy were to determine the body composition of the probands and to clarify possible relationships between results of these body compartment determinations and more simple somatometric variables, and to use the cross-sectional data as a basis for a prospective longitudinal geriatric/gerontological study.
Abstract: The objectives of this substudy within the population study “70-year-old people in Gothenburg, Sweden” were to determine the body composition of the probands and to clarify possible relationships between results of these body compartment determinations and more simple somatometric variables. The cross-sectional data will be used as a basis for a prospective longitudinal geriatric/gerontological study. The subsample comprised 66 males and 76 females, of whom 49 males and 56 females underwent a complete examination. The probands examined were considered representative of the 70-year-old population in Gothenburg. Total body potassium was estimated by using a whole body counter and total body water with an isotope dilution technique using tritiated water as a tracer. Body cell mass, intracellular and extracellular water, body fat and fat-free extracellular solids were then calculated from body weight, total body potassium and total body water using certain assumptions, the relevance of which in this age group is discussed. Average values of body weight were 76.2 kg and 66.3 kg, of body cell mass 28.1 kg and 20.3 kg and of body fat 12.5 kg and 18.1 kg in males and females, respectively. It was possible from body weight and subscapular skinfold in males and from body weight, thigh and triceps skinfold in females to reach a proportion of explained variance of body fat of 58 per cent and 76 per cent, respectively. There was a good correlation between body fat and the difference between body weight and “ideal body weight” as defined by Lindberg and collaborators, 1956. A preliminary comparison between the current data and corresponding data from cross-sectional studies of middle-aged individuals in Gothenburg showed that the amount of fat was similar in the two age groups. Body cell mass seemed to be of the same order of magnitude in 70-year-old as in middle-aged females, but showed a lesser value in 70-year-old than in middle-aged males.
01 Jan 2009
TL;DR: A new BIS device (ImpediVet™), designed for body composition measurements in animals, was assessed for precision and accuracy in measuring TBW, FFM and FM in rats and provided a precise and accurate means to determine in vivo body composition in rats.
Abstract: OBJECTIVE: Bioelectrical impedance analysis (BIA) of hydration and body composition has made significant progress during the past 3 decades. With the development of Bioimpedance spectroscopy (BIS), bioimpedance has been expanded to reliably predict extracellular fluid (ECF) and total body water (TBW), allowing the calculation of fat-free mass (FFM) and fat mass (FM). In this study, a new BIS device (ImpediVet™), designed for body composition measurements in animals, was assessed for precision and accuracy in measuring TBW, FFM and FM in rats. METHODS: In a validation study, 25 rats were measured for body composition (TBW, FFM and FM) using BIS and chemical carcass analysis (CCA). BIS precision was assessed by the coefficient of variation using multiple BIS readings, while BIS accuracy was assessed by regression analysis of BIS and CCA values for each body compartment. In a cross-validation study, prediction equations generated from the validation group for TBW, FFM and FM were applied to an independent cohort of 25 rats that were measured by BIS and CCA. Linear regression analysis and paired t-tests were used to assess significance of relationships and measurement differences within groups. RESULTS: In the validation study, BIS was highly correlated with CCA for TBW (r(2)=0.988), FFM (r(2)=0.987) and FM (r(2)=0.966). Even so, BIS significantly underestimated TBW (mean: -31.07 g, -13.3%, p<0.001) and FFM (-50.69 g, -15.5%, p<0.001), while overestimating FM (+65.75 g, +63.5%, p<0.001). In the independent, cross-validation group of rats the prediction equations accurately predicted carcass values for TBW (-0.2%, p=0.350), FFM (-0.2%, p=0.457) and FM (+1.5%, p=0.508). CONCLUSION: Based on these results, BIS provided a precise and accurate means to determine in vivo body composition in rats.
TL;DR: Zinc supplementation to the diets of HD patients may be of value to prevent the malnutrition and positive correlations were found for body weight–fasting glucose and body weight-leptin and negative correlation was found for SGA score–ghrelin.
Abstract: This study was performed to investigate the serum zinc (Zn), plasma ghrelin, leptin levels and nutritional status, and to evaluate the potential association between malnutrition and these investigated parameters in malnourished hemodialysis (HD) patients. Fifteen malnourished HD patients, aged 42.9 ± 2.11 years, who underwent the HD for 46.44 ± 7.1 months and 15 healthy volunteers, aged 41.0 ± 2.17 years, were included in this study. The nutritional status of the subjects was determined by the subjective global assessment (SGA). Anthropometric measurements were taken by bioelectrical impedance after HD. Blood samples were collected for the analysis of zinc (Zn), ghrelin, leptin, and selected blood parameters. The HD patients consumed less energy and nutrients than controls. In HD patients, body weight, body mass index (BMI) (p < 0.001), basal metabolic rate (BMR), body fat, lean body mass (LBM), serum Zn, copper (Cu) (p < 0.05), sodium (Na) (p < 0.01), glucose (p < 0.05), albumin (p < 0.01), total cholesterol (p < 0.001), and ghrelin (p < 0.05) were lower whereas body water ratio (p < 0.001), serum potassium (K) (p < 0.01), inorganic phosphorous (Pi), blood urea nitrogen, creatinine (p < 0.001), and plasma insulin (p < 0.05) levels were higher than the controls. No difference existed between HD patients and controls regarding plasma leptin levels. There were positive correlations for body weight–fasting glucose and body weight–leptin (p < 0.05), body weight–BMI and body weight–LBM (p < 0.01); body fat–leptin (p < 0.05); BMI–fasting glucose, BMI–leptin, and BMI–body fat (p < 0.05); albumin–hemoglobin and albumin–insulin (p < 0.05). Negative correlation was found for SGA score–ghrelin (p < 0.05). Malnutrition in HD patients may result from inadequate energy and nutrient intake and low Zn and ghrelin levels. Zinc supplementation to the diets of HD patients may be of value to prevent the malnutrition.
TL;DR: It is concluded that ultra-cycling in contrast to ultra-running leads to no reduction in skeletal muscle mass.
Abstract: Ultra-endurance races lead to an enormous energy deficit, and a decrease in body mass in the form of fat mass as well as skeletal muscle mass can be found. The decrease in skeletal muscle mass has been demonstrated in ultra-runners. We investigated therefore, in an ultra-cycling race, whether ultra-cyclists also suffered a decrease in body mass and whether we could find changes in skeletal muscle mass and/or fat mass. The anthropometric method was used to determine body mass, skeletal muscle mass and fat mass in 28 male Caucasian, non-professional, ultra-cyclists before and after a 600 km ultra-cycling race. In order to quantify hydration status, we measured total body water, haematocrit, plasma sodium and urinary specific gravity. In addition, plasma urea was determined as a marker of protein catabolism. Body mass as well as fat mass decreased highly significantly (p 0.05). The post race minus pre race difference (Delta) in body mass was associated with Delta fat mass (p<0.05). Urea increased highly significantly (p<0.01); however Delta urea was not associated with Delta skeletal muscle mass. We concluded that ultra-cycling in contrast to ultra-running leads to no reduction in skeletal muscle mass.
01 Dec 2009
TL;DR: A revision of bioelectric impedance as a technique to evaluate body composition is made, aspects related to its methodological assumptions are presented, as well as its advantages, limitations and applications in the estimation of body composition of children and adolescents.
Abstract: The analysis of body composition constitutes the center of nutritional state evaluation. Its estimation in the pediatric area has become highly relevant due to the growing prevalence of obesity in the first stages of life and the adverse effects on health. Bioelectrical impedance is one of the methods developed to estimate body composition in research as well as in clinic. Bioelectrical impedance is based on the opposition of cells, tissues or body fluids to the pass of an electric current. This method measures total body water and allows the estimation of fat and fat free body mass. Among its advantages are low cost, easy transportation and handling and low variability between observers. This article makes a revision of bioelectric impedance as a technique to evaluate body composition. Aspects related to its methodological assumptions are presented, as well as its advantages, limitations and applications in the estimation of body composition of children and adolescents. The applicability and validity shown by bioelectric impedance in epidemiologic studies place it next to reliable methods for the study of body composition.An Venez Nutr 2009;22 (2): 105-110.
TL;DR: The shift of the volume-aldosterone curve in haemodialysis subjects suggests that end-stage kidney disease is a state of high volume and inappropriately high aldosterone, which has important clinical implications, as dialysis patients may benefit from both volume reduction and mineralocorticoid receptor blockade.
Abstract: Introduction. Sodium loading, and subsequent volume expansion, suppresses aldosterone levels in individuals with normal renal function. We hypothesised that loss of renal function impairs this volume-aldosterone relationship. Materials and methods. With multifrequency bioimpedance spectroscopy, we measured total body water (TBW), extracellular volume (ECV), and intracellular volume in five haemodialysis patients at varied states of hydration and in five healthy volunteers during low-, normal-, and high-salt diets. Serum aldosterone, potassium, and C-reactive protein were measured simultaneously. Scatterplots and general estimating equations were used to examine the relationship among these variables. Results. In healthy volunteers with salt loading, and in haemodialysis subjects with increased inter-dialytic weight gain, expansion of ECV led to reciprocal declines in serum aldosterone concentrations. The relationship was more profound in healthy volunteers (p<0.001) than in haemodialysis subjects (p=0.1). Notably, haemodialysis subjects posted consistently higher levels of ECV (median 49.6% TBW, IQR 43.9–51.8% compared to 41.1%, 39.9–42.8% in volunteers) and serum aldosterone (median 26.7 ng/dl, IQR 19.8–29.6 compared to 12.4 ng/dl, 8.8–16.0 in volunteers). Serum potassium did not appear to influence aldosterone concentration (p=0.9). Conclusions. The shift of the volumealdosterone curve in haemodialysis subjects suggests that end-stage kidney disease is a state of high volume and inappropriately high aldosterone. These data have important clinical implications, as dialysis patients may benefit from both volume reduction and mineralocorticoid receptor blockade.
01 Feb 2009
TL;DR: The Tanita TBF-310 foot-to-foot BIA body composition analyser with the manufacturer's prediction equations is not recommended for application to individual children who are overweight and obese although it may be of use for obtaining group mean values.
Abstract: OBJECTIVES: To examine the validity of body composition estimates obtained using foot-to-foot bio-electrical impedance analysis (BIA) in overweight and obese children by comparison to a reference four-compartment model (4-CM). SUBJECTS/METHODS: 38 males: age (mean +/- sd) 13.6 +/- 1.3 years, body mass index 30.3 +/- 6.0 kg.m(-2) and 14 females: age 14.7 +/- 2.2 years, body mass index 32.4 +/- 5.7 kg.m(-2) participated in the study. Estimates of fat-free mass (FFM), fat mass (FM) and percentage body fat (PBF) obtained using a Tanita model TBF-310 and a 4-CM (derived from body mass, body volume, total body water and total body bone mineral measurements) were compared using bias and 95% limits of agreement (Tanita minus 4-CM estimates). RESULTS: Body composition estimates obtained with the Tanita TBF-310 were not significantly different from 4-CM assessments: for all subjects combined the bias was -0.7kg for FM, 0.7kg for FFM and -1.3% for PBF. However, the 95% limits of agreement were substantial for individual children: males, up to +/-9.3kg for FFM and FM and +/-11.0% for PBF; females, up to +/-5.5kg for FFM and FM and +/-6.5% for PBF. CONCLUSIONS: The Tanita TBF-310 foot-to-foot BIA body composition analyser with the manufacturer's prediction equations is not recommended for application to individual children who are overweight and obese although it may be of use for obtaining group mean values.
TL;DR: It is hypothesized that direct measurement of fat‐free mass index by dual‐energy X‐ray absorptiometry (DEXA) would provide superior assessment of body composition in COPD.
Abstract: Background and objective: Mortality and morbidity in COPD have been related to reduced FEV1 as well as indices of body composition. Different techniques used to evaluate body composition may vary in accuracy, particularly in conditions with altered fluid balance such as COPD. We hypothesized that direct measurement of fat-free mass index (FFMI) by dual-energy X-ray absorptiometry (DEXA) would provide superior assessment of body composition in COPD.
Methods: We measured body composition in 31 patients with COPD randomly selected from a teaching hospital clinic. To estimate total body water (TBW) and FFMI, skin-fold anthropometry, bioelectrical impedance analysis (BIA) with Schols and Lukaski equations as well as DEXA, total body potassium by whole-body γ-counting (TBK) and in vivo neutron activation analysis were used. Combined body composition methods providing precise estimations of TBW were used for comparisons. Bland–Altman analyses, ANOVA and χ2-testing were used to examine data.
Results: Mean BMI was 27.6 ± 5.34 kg/m2 (mean ± SD). Estimations of TBW were similar using Schols BIA or by using combined body composition methods. FFMI did not vary significantly between grades of COPD severity but was significantly different when assessed using DEXA and other methods. Calculated FFM hydration was significantly different from the fixed hydration factor used to calculate FFMI from BIA TBW (P < 0.05).
Conclusion: The Schols BIA method incorporates a fixed hydration factor that may lead to an erroneous estimation of FFMI with ensuing clinical implications. DEXA can be used to obtain accurate and comprehensive assessments of body composition and should be the preferred investigation in COPD.
TL;DR: The severity of OSAHS correlated with body fat and with body water more strongly than with general and cervical obesity and abdominal adiposity may predict OSA HS severity better than neck circumference.
Abstract: Obstructive sleep apnea-hypopnea syndrome (OSAHS) is characterized by repeated breathing pauses during sleep and is closely associated with obesity. Body fat is known to be a predictive factor for OSAHS and its severity. To study the correlation between the severity of OSAHS and body composition measurements. 30 patients with OSAHS (21 men, 9 women, mean age 45.1 years, mean apnea-hypopnea index = 29.6/hour) were included in the study after full polysomnography. They were divided into 3 groups according to the apnea-hypopnea index (AHI): mild OSAHS (mean AHI 10.9/h), moderate OSAHS (mean AHI 23.9/h) and severe OSAHS (mean AHI 53.9/h). Body composition (body fat, body water and dry lean mass) was assessed using bioelectric impedance assay (BIA). Other measurements included neck and abdominal circumferences and body mass index (BMI). Pearson's coefficient (r) was used to express correlations between AHI and the following parameters: BMI, neck and abdominal circumferences, body fat, dry lean mass, and body water. Wilcoxon Sum-of-Ranks (Mann-Whitney) test for comparing unmatched samples was used to compare anthropometric and body composition measurements between groups. The correlation between AHI and BMI was weak (r = 0.38). AHI correlated moderately with neck circumference (r = 0.54), with neck circumference corrected by height (r = 0.60), and more strongly with body fat (r = 0.67), with body water (r = 0.69) and with abdominal circumference (r = 0.75). There was a strong negative correlation between AHI and dry lean mass (r = - 0.92). There were significant differences in body fat, body water, neck circumference corrected by height and abdominal circumference (Wilcoxon Sum-of-Ranks, p < 0.01), between mild and severe OSASH groups, but not in BMI (Wilcoxon Sumof-Ranks, W = 86.5; p = 0.17). In our study, the severity of OSAHS correlated with body fat and with body water more strongly than with general and cervical obesity. Abdominal adiposity may predict OSAHS severity better than neck circumference.
TL;DR: TBW in hospitalized elderly patients can be estimated noninvasively by bedside BIA, whereas standard prediction equations uniformly over- or underestimated TBW in individuals and whole group population.
Abstract: BODY composition measurements are important to assess nutritional depletion and lean muscle mass wasting in elderly individuals and acutely ill patients. Information on the total body water (TBW) can be used to estimate body composition and its compartments such as fat-free mass, fat mass, and body solids (1–4). Rapid knowledge of patient TBW can contribute to diagnosis, and management of fluid and electrolyte imbalance. TBW is composed of two compartments: intracellular water (ICW) and extracellular water (ECW). ICW consists of the fluid in the muscle and organ cells and ECW includes plasma, interstitial fluid, and connective tissue fluids.
In healthy humans, for rapid approximate estimates of TBW, simple anthropometric measurements can be used with considerable accuracy (5–9). However, in acutely ill patients, estimated TBW does not reliably reflect fat-free mass due to disturbances of ICW caused by protein malnutrition, changes in TBW, and changes in the ratio of ICW and ECW due to injury and inflammation (10–14). ECW occupies approximately 25% of the total body mass; however, a 40% increase in ECW would result in only a 10% increase in total volume, which may not be detected (15). This is of considerable clinical importance because excessive fluid retention in the extracellular space is known to cause increased morbidity in acutely ill patients (15–17). Moreover, a shift in the ICW/ECW ratio could occur without a large change in total volume.
To accurately measure TBW and the distribution of water between the ICW and ECW compartments, isotopic dilutions are used. Briefly, TBW is measured after oral administration of deuterated water into the blood stream and measuring the exchange of labeled hydrogen atoms with hydrogen atoms associated with carboxyl, hydroxyl, and amino acid groups. ECW is measured after oral administration of sodium bromide and measuring the bromide blood concentrations. Bromide space is determined by the area under the curve as compared with known bromide standards. The ICW is calculated as the difference between TBW and ECW. Although these methods are considered the “gold standard” methods to determine TBW, they are expensive, time consuming, and not readily available at the bedside. Urine osmolality is another important indicator of hydration status (18), but does not permit quantification of TBW.
An alternative technique to predict TBW in acutely ill patients is bioelectrical impedance analysis (BIA). This simple technique introduces a single-frequency (50 kHz) signal through two outer pairs of electrocardiograph-type electrodes placed on the right wrist and right ankle. Two inner pairs of electrodes detect resistance to the introduced signal as a function of body conductance. The circuits are designed to measure two components of the alternating current signal: resistance and reactance. The resistance reflects extracellular space, and the reactance indicates cellular activity. These currents are conducted almost completely through the fluid compartment of the fat-free mass, which is an equivalent of TBW. The opposition to the flow of current, or resistance, is measured and used to predict TBW (3,4). BIA has been shown to be a simple, rapid, noninvasive, and reproducible technique to measure total body impedance in healthy adults (19–21). It has previously been used in assessing TBW in malnourished patients who underwent abdominal surgery (12,16,22). What is not clear is whether BIA is a useful and an accurate tool to predict TBW in acutely ill patients with nonuniform fluid distribution.
In acutely ill patients, the amount of lean muscle mass is often overestimated by anthropometric equations when compared with actual values measured by the segmental compartments of TBW or ECW. Once validated, BIA could be used to determine fluid status, estimate fat and fat-free mass, assess nutritional states, and test hypotheses related to drug doses on the individualized level in acutely ill elderly patients.
The goal of the study was to determine the agreement between TBW for commonly used equations for the prediction of TBW against the reference methods, deuterium oxide and sodium bromide dilution, in acutely ill hospitalized elderly persons.
TL;DR: Gambian infants characterised by growth faltering had LM deficits that increased with age, and showed indications of a more central distribution than in the reference infants, while creatinine excretion is not recommended for LM estimation in this population.
Abstract: Gambian infants show growth faltering, but the underlying body composition is unknown. The present study aimed to compare body composition in Gambian and UK infants using 2H dilution; and to evaluate accuracy of bioelectrical impedance analysis (BIA) and creatinine excretion for estimating lean mass (LM), using 2H as the reference. Body composition was measured in thirty Gambian infants, aged 3-18 months, using (1) anthropometry, (2) 2H, (3) BIA (equation of Fjeld et al. Pediatr Res (1990), 27, 98-102) and (4) 5 h urinary creatinine excretion. Compared with UK reference data, Gambian infants were light, short and had reduced BMI and skinfolds. The subscapular skinfold standard deviation score (SDS) was greater than the triceps SDS (P < 0.01), indicating central fat preservation. Both LM and fat mass were reduced in Gambian infants, with or without adjustment for length. However, whereas the Gambia-UK difference in LM increased with age, that in fat mass decreased. Average creatinine excretion was similar to that expected (95.5 (sd 23.2) % recovery), but LM estimates showed unacceptable error in individuals. BIA using Fjeld's equation overestimated total body water and LM (P < 0.001), hence a new equation was developed, with standard error of 0.47 kg LM. In conclusion, Gambian infants characterised by growth faltering had LM deficits that increased with age. However, adiposity increased with age, and showed indications of a more central distribution than in the reference infants. A new BIA equation for LM prediction is presented; however, creatinine excretion is not recommended for LM estimation in this population.
TL;DR: The aims of this study were to quantify body water compartment changes in cirrhotic patients, with and without ascites, and to elucidate the value of body water analysis for predicting the development of ascites.
TL;DR: Preliminary results suggest that progestational activity of CMA could balance both fluid retention and weight gain elicited by EE2 and reduce FM without altering TBW, ICW, ECW.
TL;DR: A multistage ultraendurance triathlon over five times the Ironman distance within five consecutive days leads in one ultra endurance triathlete to minimal changes in body mass, fat mass, muscle mass, skeletal Muscle mass, and total body water; the increase in TBW might be explained by the increase of plasma volume.
Abstract: A multistage ultraendurance triathlon over five times the Ironman distance within five consecutive days leads in one ultraendurance triathlete to minimal changes in body mass (BM; -0.3 kg), fat mass (FM; -1.9 kg), skeletal muscle mass (SM; no change), and total body water (TBW; +1.5 l). This might be explained by the continuously slower race times throughout the race every day and the positive energy balance (8,095 kcal), although he suffered an average energy deficit of -1,848 kcal per Ironman distance. The increase of TBW might be explained by the increase of plasma volume (PV) in the first 3 days. The increase of PV and TBW could be a result of an increase of sodium, which was increased after every stage. We presume that this could be the result of an increased activity of aldosterone.
TL;DR: Electrolyte intake should be adjusted according to the results of regular laboratory analyses, and patients with normal fluid and electrolyte balance should receive intakes follwing standard recommendations with PN.
Abstract: A close cooperation between medical teams is necessary when calculating the fluid intake of parenterally fed patients. Fluids supplied parenterally, orally and enterally, other infusions, and additional fluid losses (e.g. diarrhea) must be considered. Targeted diagnostic monitoring (volume status) is required in patients with disturbed water or electrolyte balance. Fluid requirements of adults with normal hydration status is approximately 30-40 ml/kg body weight/d, but fluid needs usually increase during fever. Serum electrolyte concentrations should be determined prior to PN, and patients with normal fluid and electrolyte balance should receive intakes follwing standard recommendations with PN. Additional requirements should usually be administered via separate infusion pumps. Concentrated potassium (1 mval/ml) or 20% NaCl solutions should be infused via a central venous catheter. Electrolyte intake should be adjusted according to the results of regular laboratory analyses. Individual determination of electrolyte intake is required when electrolyte balance is initially altered (e.g. due to chronic diarrhea, recurring vomiting, renal insufficiency etc.). Vitamins and trace elements should be generally substituted in PN, unless there are contraindications. The supplementation of vitamins and trace elements is obligatory after a PN of >1 week. A standard dosage of vitamins and trace elements based on current dietary reference intakes for oral feeding is generally recommended unless certain clinical situations require other intakes.
TL;DR: This study shows that TOBEC is a potentially valuable tool for studying changes in body composition of small mammals and may provide insight into the physiological impacts of various life history stages such as postnatal growth, reproduction, and hibernation.
Abstract: The ability to measure body composition is critical for studying the physiological ecology of animals. This is particularly true for small mammals that have a high metabolic rate. We evaluated a nondestructive method of body composition analysis that would allow accurate assessment of body fat, body water, and lean mass. We used total body electrical conductivity (TOBEC) to estimate body composition in the little brown myotis (Myotis lucifugus). In a sample of 46 individuals, TOBEC was both accurate and precise in estimating total body water and lean mass but was less effective at estimating total body fat. Mass-independent or whole-body compartments (i.e., total body water, total body fat, lean dry mass, and lean body mass) were more accurately estimated than mass-dependent or mass-specific body composition compartments (i.e., water content, fat index, and % lean dry mass). The TOBEC measurements we made using an SA-3000 analyzer were influenced by extremes in body temperature, as well as by aluminum and incoloy wing bands. Our study also presents a new method of restraint especially suited for small mammals and birds that increases precision of TOBEC measurements. This study shows that TOBEC is a potentially valuable tool for studying changes in body composition of small mammals and may provide insight into the physiological impacts of various life history stages such as postnatal growth, reproduction, and hibernation.