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Objective: The aim was to determine the most appropriate field techniques to measure %BF when both euhydrated and dehydrated. Design: A cross-sectional descriptive study was undertaken. Setting: South Africa. Subjects: 17 male apprentice jockeys (mean age 18.8 ± 1.7 years). Outcome measures: Agreement of %BF results determined using predictive equations based on skinfold thickness measurements and bioelectric impedance analysis (BIA) with that of the reference method, euhydrated deuterium dilution (eDD). Results: The mean %BF according to eDD was 9.5 ± 2.8%. The skinfold equations by Slaughter et al. (1988) for ages 8–18 years in either hydration state, Durnin and Womersley1 using either Siri2 or Brožek et al.3 for ages 17–19 years when dehydrated only, and the Van Loan et al.4 BIA equation when euhydrated only were the most acceptable methods. Conclusion: Regardless of hydration status, the skinfold equation by Slaughter et al.5 is recommended for jockey apprentices 18 years and younger. For those > 19 years, the hydration state must be confirmed prior to measurement. If euhydrated, the Van Loan et al.4 BIA equation is recommended and if dehydrated the Durnin and Womersley1 using either Siri2 or Brožek et al.3 is recommended. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Ornithology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The three-compartment (3-C) model of physique assessment (fat mass, fat-free mass, water) incorporates total body water (TBW) whereas the two-compartment model (2-C) assumes a TBW of 73.72%. Deuterium dilution (D2O) is the reference method for measuring TBW but is expensive and time consuming. Multifre-quency bioelectrical impedance spectroscopy (BIS SFB7) estimates TBW instantaneously and claims high precision. Our aim was to compare SFB7 with D2O for estimating TBW in resistance trained males (BMI >25kg/m²). We included TBWBIS estimates in a 3-C model and contrasted this and the 2-C model against the reference 3-C model using TBWD2O. TBW of 29 males (32.4 ± 8.5 years; 183.4 ± 7.2 cm; 92.5 ± 9.9 kg; 27.5 ± 2.6 kg/m²) was measured using SFB7 and D2O. Body density was measured by BODPOD, with body composition calculated using the Siri equation. TBWBIS values were consistent with TBWD2O (SEE = 2.65L; TE = 2.6L) as were %BF values from the 3-C model (BODPOD + TBWBIS) with the 3-C reference model (SEE = 2.20%; TE = 2.20%). For subjects with TBW more than 1% from the assumed 73.72% (n = 16), %BF from the 2-C model differed significantly from the reference 3-C model (Slope 0.6888; Intercept 5.093). The BIS SFB7 measured TBW accurately compared with D2O. The 2C model with an assumed TBW of 73.72% introduces error in the estimation of body composition. We recommend TBW should be measured, either via the traditional D2O method or when resources are limited, with BIS, so that body composition estimates are enhanced. The BIS can be accurately used in 3C equations to better predict TBW and BF% in resistance trained males compared with a 2C model. [ABSTRACT FROM AUTHOR]

Background: Measures that better describe "healthy" and sustainable recovery during nutritional treatment of children with moderate acute malnutrition (MAM) are needed.Objectives: We compared changes to body composition among children receiving 1 of 4 specialized nutritious food (SNFs) during treatment of MAM and by recovery and relapse outcomes.Methods: The study was nested within a prospective, cluster-randomized, community-based, cost-effectiveness trial assessing 4 SNFs to treat children aged 6-59 mo with MAM [midupper arm circumference (MUAC) ≥11.5 cm and <12.5 cm without bipedal edema] in Sierra Leone. Biweekly SNF rations (1 of 3 fortified-blended foods or a lipid-based nutrient supplement) were given until children recovered (MUAC ≥12.5 cm), or up to 7 rations (∼12 wk). Deuterium dilution was used to estimate fat-free mass (FFM) and fat mass (FM) at enrollment and after 4 wk of treatment to ensure similar treatment exposure among the participants. Another MUAC measurement was performed among recovered children 4 wk after program exit to determine whether recovery was sustained. ANOVA, paired t tests, and linear regression models were used to determine significant differences in changes from baseline to 4 wk.Results: Among 312 analyzed participants, mean baseline weight comprised ∼80% FFM; mean weight gained after 4 wk comprised ∼82% FFM. Changes in FM and FFM among 4 SNFs were similar. Children who recovered gained more weight (241%), FFM (179%), and weight-for-height z score (0.44 compared with 0) compared with those who did not recover; sustainers gained 150% more weight. FM gains were positive among recovered children and sustainers, as well as negative among those who did not recover or sustain recovery, but not significantly different.Conclusions: Four SNFs had similar effects on body composition in children after 4 wk of treatment for MAM, showing a healthy pattern of weight gain, the majority being FFM. Differential responses to treatment underscore a need for further research to provide targets for healthy, sustainable recovery. This trial was registered at clinicaltrials.gov as NCT03146897. [ABSTRACT FROM AUTHOR]

Background: Although the impact of gestational weight gain (GWG) on birth weight in twin pregnancies has been demonstrated, the specific components of GWG have not been delineated for twin gestations. Fetal body composition has been shown to be modifiable in singleton gestations based on nutritional intervention strategies and may prove to have similar modifications in twin gestations. Objective: We aimed to determine the relation of maternal body composition changes to birth weight, birth length, and neonatal fat mass (FM) in dichorionic-diamniotic twin pregnancies. Design: This is a prospective study of 20 women with twin gestations. Comparisons were made between body composition variables during each trimester and for the entire pregnancy and compared with the outcomes of birth weight, neonatal fat percentage, and birth length. Results: GWG within or above compared with below the IOM recommendations was associated with higher birth weights (P = 0.03, P = 0.04, respectively), but also with higher postpartum weight retention (P = 0.001). Total maternal protein gain over the pregnancy was positively associated with birth weight (P = 0.03). Changes in maternal fat-free mass (FFM), total body water (TBW), and FM from the first to the third trimester were not associated with either birth weight or neonatal FM percentage. However, maternal FM change from the second to the third trimester was significantly correlated to neonatal FM percentage (P = 0.02). Third trimester GWG and total protein gain were positively correlated with neonatal birth length (P = 0.02 and 0.03, respectively). Maternal FFM over all 3 trimesters showed a positive relation with neonatal birth length (P = 0.01). Conclusions: Significant increases in maternal protein are associated with greater birth weight and neonatal birth length. Protein accretion, in contrast to TBW and FM gains, may be the most critical component of maternal GWG in dichorionic twin gestations. [ABSTRACT FROM AUTHOR]

Childhood malnutrition is highly prevalent and associated with high mortality risk. In observational and interventional studies among malnourished children, body composition is increasingly recognised as a key outcome. The deuterium dilution technique has generated high-quality data on body composition in studies of infants and young children in several settings, but its feasibility and accuracy in children suffering from moderate acute malnutrition requires further study. Prior to a large nutritional intervention trial among children with moderate acute malnutrition, we conducted pilot work to develop and adapt the deuterium dilution technique. We refined procedures for administration of isotope doses and collection of saliva. Furthermore, we established that equilibration time in local context is 3 h. These findings and the resulting standard operating procedures are important to improve data quality when using the deuterium dilution technique in malnutrition studies in field conditions, and may encourage a wider use of isotope techniques. [ABSTRACT FROM PUBLISHER]

Steller sea lion ( Eumetopias jubatus) young-of-the-year ( YOY) are nutritionally dependent upon their dam through the majority of their first year. Several indices of body condition were measured in YOY 1.5-9 mo of age captured in Southeast Alaska ( n = 122), the Gulf of Alaska ( n = 182), and the Aleutian Islands ( n = 38) to test the hypothesis that nutritional stress impacted the ability of adult female Steller sea lions to adequately nourish their late gestation YOY in the central Aleutian Islands in the early 2000s. Body mass (kg) and percent total body lipid content (% TBL) increased with age in all three regions of Alaska that were sampled ( P < 0.05). Young-of-the-year 7-9 mo of age were leaner in Southeast Alaska (27.6% ± 1.0%) and Gulf of Alaska (29.5% ± 0.8%) than in the Aleutian Islands (35.7% ± 1.2%, P < 0.001). Condition indices calculated from morphometric measures did not strongly predict the % TBL measured by isotope dilution. The trend for Aleutian Island YOY to have larger body mass and larger body fat reserves are counter to what would be expected if dams were unable to adequately provision their late lactation YOY due to inadequate food availability in the central Aleutian Islands. [ABSTRACT FROM AUTHOR]

ABSTRACT The nearshore and offshore waters of southern New England provide some of the most important wintering habitat for sea ducks in North America. Understanding changes in sea duck body composition during winter could provide insights into current habitat quality and potential effects of anthropogenic disturbances on the body condition of sea ducks. We used the deuterium dilution method, a nonlethal approach, to investigate intraseasonal variation and differences between genders in body composition of 86 adult common eiders ( Somateria mollissima) during winter (2011 and 2012) in southern New England. Both male ( n = 39) and female ( n = 47) eiders increased fat mass by 75% in late winter compared with early winter. Wet lean mass of males remained constant throughout the winter, while that of females decreased by 10%. These seasonal increases in fat stores of eider suggest that birds were able to secure adequate resources to improve their body condition over winter. Our estimates of body composition of eider during winter in southern New England can be used as a baseline when conducting future research to evaluate effects of anthropogenic disturbance and disease. © 2016 The Wildlife Society. [ABSTRACT FROM AUTHOR]

ABSTRACT We conducted the first validation of the deuterium dilution method as a nonlethal technique for estimating body composition of a sea duck. We captured male ( n = 11) and female ( n = 8) American common eiders ( Somateria mollissima dresseri) during winters of 2011-2012 and 2012-2013 in southern New England, USA, and compared their directly measured body composition with that estimated using deuterium-dilution. The best-supported linear regression models predicted wet lean and fat mass with, on average, 2.0% and 20.2% relative errors, respectively. The deuterium dilution method provides field biologists and managers with a nonlethal method for accurately estimating body composition of common eider during winter. The method is broadly applicable to other migratory birds and can be used to evaluate the effects of ecological and anthropogenic drivers on body composition dynamics. © 2016 The Wildlife Society. [ABSTRACT FROM AUTHOR]

There is no data on the prevalence of overweight and obesity in young Syrian boys. Therefore, the present study aimed to provide baseline and reference data on the prevalence of overweight and obesity among young Syrian boys using skin-fold thickness measurements and deuterium dilution (DD) as a reference method. The sample of 2470 healthy Syrian 18- to 19-year-old boys were enrolled in this study. SFTs were measured at the biceps (B), triceps (T), subscapular (SI) and suprailiac locations (SS) were done and validated using the DD technique as a reference method. Receiver operating characteristics (ROC) curve was drawn to determine appropriate cut-off points of the Σ2 limb SFT (T+B), Σ2 trunk SFT (SI+SS), Σ4 SFT (T+B+SI+SS) and Log Σ4 SFT for defining overweight and obesity. The overall prevalence of overweight and obesity in young Syrian boys, based on biceps SFT, triceps SFT, subscapular SFT, suprailiac SFT, Σ2 limb SFT, Σ2 trunk SFT, Σ4 SFT, logarithm Σ4 SFT, and DDT were 35.3%, 32%, 31.6%, 14.8%, 32.9%, 26.6%, 28.1%, 24.1%, 46.5%, respectively. Strongly positive correlation was found between SFT and total body fat in adolescents. For diagnosing overweight on the basis of Σ2 limb SFT, Σ2 trunk SFT, Σ4 SFT and logarithm Σ4 SFT, we propose the following cut-off points: 17.25 mm, 23.50 mm, 39.25 mm and 1.60, respectively. To predict obesity, Σ2 limb SFT, Σ2 trunk SFT, Σ4 SFT and logarithm Σ4 SFT threshold were increased to 23.25 mm, 32.50 mm, 55.25 and 1.75, respectively. Basing on SFT clearly leads to underestimates of the prevalence of weight problems among young boys. SFT measurement screen missed 11.2 to 31.7% of overall overweight and obesity cases. [ABSTRACT FROM AUTHOR]

Background: Equations based on single-frequency bioelectrical impedance analysis at 50 kHz for determination of total body water content (TBW) have been previously validated in healthy non-sedated beagle dogs. We investigated whether these equations are predictive of TBW in various canine breeds by comparing the results of these equations with TBW values evaluated directly by deuterium oxide (D2O) dilution. Methods: Total body water content of 13 healthy adult pet dogs of various breeds was determined directly using D2O dilution and indirectly using previous equations based on values obtained with a portable bioelectric impedance device. Paired Student's t-tests were used to compare TBW obtained by single-frequency bioelectrical impedance analysis and D2O dilution. A p-value of <0.05 was considered statistically significant for all analyses. Results: Significant differences were observed between TBW determined by the reference method and the values obtained with both predictive equations. Conclusions: The proposed equations including single-frequency bioelectrical impedance analysis parameters validated at 50 kHz in healthy adult beagles need to be modified including morphological parameters such as body size and shape in a first approach. As in humans, morphological-specific equations have to be developed and validated. [ABSTRACT FROM AUTHOR]

Aim Multi-frequency bioelectrical impedance analysis ( MF- BIA) may provide a quick, cost-efficient method of total body water ( TBW) assessment. We compared TBW estimates from the Biospace In Body 520, 720, and S10 MF- BIA devices to TBW estimates from isotopic deuterium dilution ( D2 O). Methods TBW was measured in 25 men and 25 women, 18-49 years, 73.6 ± 15.4 kg on each of the three devices and from D2 O analysis. Results All MF- BIA devices significantly overestimated TBW compared to D2 O TBW for men (4.7-5.4 kg, 10.8-12.4%; P < 0.01) and women (3.7-4.3 kg, 12.3-14.3%; P < 0.01). Regression analyses in men revealed R2 (0.86-0.90) and SEE (1.7-2.0 kg), and in women revealed R2 (0.82-0.86) and SEE (1.5-1.6 kg). Bland and Altman analyses revealed similar limits of agreement for men (3.5-3.9 kg) and women (3.4-3.7 kg). Conclusions The Biospace InBody devices significantly overestimate TBW in men and women. The consistent bias for men and the increasing bias with increasing TBW for women may indicate that these devices are suitable for group TBW estimates in men only. [ABSTRACT FROM AUTHOR]

Background In developing countries where access to water and food is not guaranteed, women may have to travel long distances or engage in intense physical activities to gather food. This may compromise their water requirements and overall nutritional status. The aim of the study was to determine water turnover, physical activity and body composition among women in Kenya and to describe the differences between rural and urban Kenyan women. Methods Thirty women from Narok County who were not pregnant at the time of the study were recruited. Body mass index (BMI) was calculated by dividing weight in kilograms by height in meters squared. Deuterium dilution was used to determine total body water (TBW) and water turnover was measured from deuterium elimination. Fat-free mass (FFM) was calculated by assuming a constant hydration fraction of 73.2%. Accelerometers (Actigraph GT3X) were used to assess physical activity and expressed as Vector magnitude counts per day (VM/day). Simple and multiple linear regressions were used to define the determinants of water turnover. Results Mean BMI was 23.4 ± 4.1 and 21.5 ± 3.8 among rural and urban women respectively. The prevalence of overweight (BMI > 25 kg/m²) was 24.1% and of underweight (BMI < 18.4 kg/m²) was 25%. The mean total body water (TBW) was 29.3 ± 4.2 liters (L) and water turnover was 3.2 ± 0.8 liters per day (L/day). Water loss was positively associated with BMI (R² = .45, p < 0.001, n = 28) and Fat mass index (FMI) (R² = .41, p < 0.001, n = 28). Water loss was also positively associated with physical activity (PA) (R² = .25, p < 0.05, n = 22). Multiple regression analysis showed that physical activity in addition to BMI in the model explained an additional 15% of the variation in water turnover (r² = 0.53, p < 0.05; Δr² = 0.15, p < 0.05, n = 22) compared to BMI alone (r² = 0.38, p < 0.005 n = 22). Conclusion BMI together with physical activity were the strongest predictors of water loss. [ABSTRACT FROM AUTHOR]

Seals must manage their energy reserves carefully while they fast on land to ensure that they go to sea with sufficient fuel to sustain them until they find food. Glucocorticoids (GCs) have been implicated in the control of fuel metabolism and termination of fasting in pinnipeds. Here we tested the hypothesis that dexamethasone, an artificial GC, increases fat and protein catabolism, and induces departure from the breeding colony in wild, fasting grey seal pups. A single intramuscular dose of dexamethasone completely suppressed Cortisol production for 24-72 h, demonstrating activation of GC receptors. In experiment 1, we compared the effects of a single dose of dexamethasone or saline administered 10 days after weaning on fasting mass and body composition changes, Cortisol, blood urea nitrogen (BUN) and glucose levels, and timing of departure from the colony. In experiment 2, we investigated the effects of dexamethasone on short-term (5 days) changes in mass loss, body composition and BUN levels. In experiment 1, dexamethasone induced a short-lived increase in mass loss, but there was no difference in timing of departure between dexamethasone- and saline-treated pups (N=10). In experiment 2, dexamethasone increased protein and water loss and prevented a decrease in BUN levels (N=11). Our data suggest changes in Cortisol contribute to regulation of protein catabolism in fasting seal pups, irrespective of the sex of the animal, but do not terminate fasting. By affecting the rate of protein depletion, lasting changes in Cortisol levels could influence the amount of time seal pups have to find food, and thus may have important consequences for their survival. [ABSTRACT FROM AUTHOR]

Background:Air-displacement plethysmography (ADP) may be a valid and practical technique to assess body composition in a clinical setting.Objective:This study aimed to assess longitudinal changes in body composition using ADP and to compare it with the deuterium dilution technique.Design:The study was a 6-months dietary intervention, consisting of four phases. The first month, subjects were fed in energy balance (phase I). This was followed by 1 month with an energy intake of 33% of energy requirements (phase II), followed by 2 months at 67% of energy requirements (phase III) and 2 months of ad libitum intake (phase IV). Body composition was assessed using ADP (Bod Pod) and deuterium dilution at baseline and at the end of each phase. The baseline analysis included 111 subjects (88 female). Sixty-one subjects (50 female) completed all measurements and were included in the longitudinal analysis.Results:At baseline, the fat mass (FM) as assessed with the Bod Pod was on average 2.3±4.2 kg (mean±2 s.d.) higher than that assessed with deuterium dilution. The difference in FM between techniques increased significantly with increasing FM (R2=0.23; P<0.001). Both techniques showed significant changes in FM over time P<0.001). On average, FM as assessed with the Bod Pod was 2.0 kg higher than with deuterium dilution (P<0.001). During phase II, there was a significant interaction between time and method, meaning that the Bod Pod showed a larger decrease in FM than deuterium dilution.Conclusions:The Bod Pod was able to detect all changes in the body composition, but consistently measured a higher FM than deuterium dilution. [ABSTRACT FROM AUTHOR]

Water homeostasis is essential for life and optimal function and considerable interest surrounds the issue of recommendations for water consumption in healthy individuals. Objective data on water turnover in free-living individuals are limited, however. The aim of the present work was to measure water turnover in children and young adults using isotopically labeled water to provide objective data on magnitude and variability in relation to body weight, fat-free mass and physical activity level. Water turnover was measured by deuterated water dilution in 91 healthy children (40 boys, 51 girls; age 5-14 years) and 109 healthy young adults (80 women, 29 men; age 18-27 years) with a wide range of body mass index (13.3-51.8 kg/m(2)) and percent body fat (6.1-59.3%). Total energy expenditure (TEE) and resting metabolic rate were measured by the doubly labeled water technique and indirect calorimetry, respectively. Water turnover was 1.77 ± 0.57 (SD), 1.79 ± 0.44, 2.85 ± 0.82, and 3.90 ± 0.81 L/day in girls, boys, women, and men, respectively. Water turnover indexed to body surface area did not differ significantly between girls and women but was higher in men than boys. Water turnover indexed to TEE was 0.8 mL/kcal in girls and boys and 1.0 mL/kcal in women and men. This study provides objective data on water turnover for children and young adults in a temperate climate and shows that anthropometric parameters can account for the variation between girls, boys and women but not between these groups and the more active men. [ABSTRACT FROM AUTHOR]

The evaluation of body composition (BC) is relevant in the evaluation of children's health-disease states. Different methods and devices are used to estimate BC. The availability of methods and the clinical condition of the patient usually defines the ideal approach to be used. In this cross-sectional study, we evaluate the accuracy of different methods to estimate BC in Mexican children and adolescents, using the 4-C model as the reference. In a sample of 288 Mexican children and adolescents, 4-C body composition assessment, skinfold-thickness (SF), dual-energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP), and deuterium dilution (D2O) were performed, along with MRI in a subsample (52 participants). The analysis of validity was performed by correlation analysis, linear regression, and the Bland–Altman method. All methods analyzed showed strong correlations for FM with 4-C values and between each other; however, DXA and MRI overestimated FM, whereas skinfolds and ADP under-estimated FM. Conclusion: The clinical assessment of BC by means of SF, ADP, DXA, MRI and D2O correlated well with the 4-C model and between them, providing evidence of their clinical validity and utility. The results from different methods are not interchangeable. Preference between methods may depend on their availability and the specific clinical setting. [ABSTRACT FROM AUTHOR]

Copyright of Acta Medica Lituanica is the property of Vilnius University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Most techniques for measuring body composition are based on 2-component models (2-CMs) and depend on assumptions relating to the constancy of the density (DFFM) and hydration fraction (HFFFM) of fat-free mass (FFM). Objectives: The objectives were to determine whether these assumptions are systematically violated in patients with cirrhosis and to assess the validity of the estimates of body composition obtained in these patients by using 2-CM techniques. Design: Body composition was assessed by using a 4-component model (4-CM), which was based on data obtained from densitometry, deuterium dilution, and dual-energy X-ray absorptiometry, in 20 patients with cirrhosis who had no evidence of fluid retention and in 20 pair-matched healthy control subjects. The results were compared with those obtained by using "reference" and "bedside" 2-CM techniques. Results: The mean ( ± SD) DFFM was significantly lower in the patients with cirrhosis (1.091 ± 0.008 compared with 1.100 ± 0.006 kg/L; P < 0.001); no significant difference in HFFFM was observed between the patients and control subjects (74.5 ±2.6 compared with 73.5 ± 2.1), although there was greater variability in the patients. Significant differences were observed in the body-composition variables obtained by using the "reference" 2-CM techniques compared with the 4-CM-the 95% limits of agreement in the patients with cirrhosis exceeded 5% body fat and 3 kg FFM; the corresponding values for the "bedside" 2-CM techniques were 11% body fat and 7.5 kg FFM. Conclusions: Assumptions relating to the constancy of the DFFM and HFFFM are violated in patients with cirrhosis. Thus, standard 2-CM techniques provide inaccurate body composition estimates in this patient population. [ABSTRACT FROM AUTHOR]

Background: Little information is available on the validity of simple and indirect body-composition methods in non-Western populations. Equations for predicting body composition are population specific, and body composition differs between blacks and whites. Objective: We tested the hypothesis that the validity of equations for predicting total body water (TBW) from bioelectrical impedance analysis measurements is likely to depend on the racial background of the group from which the equations were derived. Design: The hypothesis was tested by comparing, in 36 African women, TBW values measured by deuterium dilution with those predicted by 23 equations developed in white, African American, or African subjects. These cross-validations in our African sample were also compared, whenever possible, with results from other studies in black subjects. Results: Errors in predicting TBW showed acceptable values (1.3- 1.9 kg) in all cases, whereas a large range of bias (0.2- 6.1 kg) was observed independently of the ethnic origin of the sample from which the equations were derived. Three equations (2 from whites and 1 from blacks) showed non significant bias and could be used in Africans. In all other cases, we observed either an overestimation or underestimation of TBW with variable bias values, regardless of racial background, yielding no clear trend for validity as a function of ethnic origin. Conclusions: The findings of this cross-validation study emphasize the need for further fundamental research to explore the causes of the poor validity of TBW prediction equations across populations rather than the need to develop new prediction equations for use in Africa. [ABSTRACT FROM AUTHOR]

OBJECTIVE:: Most body composition techniques assume constant properties of the fat-free mass (FFM), such as hydration, density and mineralisation. Previous studies suggested that FFM composition may change in childhood obesity; however, this issue has not been investigated in detail. AIM:: To compare FFM composition in obese and nonobese children. DESIGN:: Observational matched case-control analyses. SUBJECTS:: A total of 28 obese children (13 boys, 15 girls) and 22 nonobese children (10 boys, 12 girls) aged 7-14?y. Obesity was defined as body mass index centile>95. METHODS:: Measurements were made of weight, height, total body water, and body volume. Bone mineral content was estimated in a subsample. Body composition was calculated using three- and four-component models. RESULTS:: According to the three-component model (n=22 matched pairs), obese children had greater hydration (P<0.05), and reduced density (P=0.057) of FFM. According to the four component model (n=11 pairs), obese children had greater hydration (P<0.01) and reduced density (P<0.002) of FFM. The mineralisation of FFM was increased, but not significantly so. CONCLUSION:: The greater hydration and reduced density of FFM of obese children should be taken into account if body composition is to be measured with optimum accuracy during treatment programmes. These differences may be addressed by using multicomponent rather than two-component models of body composition. Although the greater mineralisation of FFM in obese children was not significant in the present study, the four-component model is best able to address the combined differences in hydration and mineralisation that occur in childhood obesity.International Journal of Obesity (2005) 29, 29-36. doi:10.1038/sj.ijo.0802834 Published online 2 November 2004 [ABSTRACT FROM AUTHOR]

Background: The accurate measurement of body composition is useful in assessments of infant growth and nutritional status. Objective: This study evaluated the reliability and accuracy of a new air-displacement plethysmography (ADP) system for bodycomposition assessment in infants. Design: Between- and within-day reliability was assessed by comparing the percentage body fat (%BF) obtained on consecutive days and on the same day, respectively, in 36 full-term infants. Accuracy was assessed by comparing %BF measured with the use of ADP and %BF measured with the use of deuterium (2H2O) dilution in 53 infants. Results: There were no significant differences in%BFbetween days (-0.50 ± 1.21%BF) or within days (0.16 ± 1.44%BF). Mean between- and within-day test-retest SDs of 0.69 and 0.72%BF, respectively, indicated excellent reliability. The %BF measurements obtained by using ADP were not significantly influenced by infant behavioral state. Mean %BF obtained by using ADP (20.32%BF) did not differ significantly from that obtained by using 2H2Odilution (20.39%BF), and the regression line [%BF(2H2O) = 0.851%BF (ADP) + 3.094] gave a high R2 (0.76) and a low SEE (3.26). The 95% limits of agreement between ADP and 2H2O (-6.84%BF, 6.71%BF) were narrower than those reported for other bodycomposition techniques used in infants. Individual differences between the 2 methods were not a function of body mass or fatness. Conclusion: ADP is a reliable and accurate instrument for determining %BF in infants, and it has the potential for use in both research and clinical settings. [ABSTRACT FROM AUTHOR]

Background: The body composition was measured in 30 female Singapore Chinese and 34 female Dutch Caucasians aged (mean ± SD) 22.7 ± 3.6 years and in 39 male Singapore Chinese and 39 male Dutch Caucasians aged 23.3 ± 3.2 years. Methods: The body fat percentage (BF%) was measured using densitometry and deuterium oxide dilution as well as a chemical four-compartment model, including fat mass, water, mineral, and protein. The chemical composition of the fat-free mass (FFM) and its density were calculated. Results: Mean body mass index (kg/m[sup 2] ) and BF% based on the four-compartment model in the four subgroups were 20.3 ± 1.5 and 29.7 ± 5.3 for the Singapore Chinese females, 22.1 ± 1.2 and 28.9 ± 5.2 for the Dutch females, 21.5 ± 2.5 and 19.4 ± 6.1 for the Singapore males, and 22.2 ± 1.8 and 15.8 ± 4.9 for the Dutch males. The contributions to the FFM of water, protein, and mineral were, respectively, 72.8 ± 1.5, 19.2 ± 1.8, and 7.9 ± 0.8% for the Singaporean females and 74.2 ± 1.4, 18.3 ± 1.5, and 7.6 ± 0.5% for the Dutch females. In males these figures were 73.2 ± 1.7, 19.6 ± 1.7, and 7.3 ± 0.5% for the Singaporeans and 72.9 ± 1.4, 20.5 ± 1.4, and 6.6 ± 0.5% for the Dutch. In females, these figures were for all components significantly different between the ethnic groups; in males the differences were significant for protein and mineral only. The calculated densities (kg/l) of the FFM were 1.1074 ± 0.0057, 1.1012 ± 0.0051, 1.1027 ± 0.0065, and 1.1004 ± 0.0055 for the Chinese females, Caucasian females, Chinese males, and Caucasian males, respectively. Conclusions: Although it cannot be excluded that the differences in density and composition of the FFM are due to methodological differences between the study sites, the findings may have consequences for the validity of single (reference) methods due to violation of normally used assumptions. The findings explain the observed underestimation of BF% from density using Siri’s formula in the Chinese subjects, especially in females. The use of deuterium oxide as a single method to determine the BF% resulted in a smaller bias than densitometry (overall 1.6 ± 2.0% for densitometry, 0.3 ± 1.7% for deuterium dilution), suggesting that the deuterium oxide method may be more suitable as a single method in comparative body composition studies.Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Single-frequency bioelectrical-impedance analyses (BIA) and bioelectrical spectroscopy (modeling multifrequency measurements; BIS) were validated as methods to predict body water (BW) compartments in 29 healthy adults. Total body water (TBW) and extracellular water (ECW) were determined by deuterium- and bromide-dilution techniques. Contribution of BIA to anthropometry and influence of the position of electrodes were examined. Stepwise-regression analysis revealed that inclusion of BIA to anthropometric data greatly improved the fit with BW compartments. Highly significant correlations were observed between BIS and BW compartments (TBW: r² = 0.98, SEE = 1.2; ECW: r² = 0.95, SEE = 0.6). Cross-correlation (14 males, and 15 females) indicated predictive potential of the method. Results from BIS and BIA were comparable, but it is argued that BIS has the potential of improved standardization of the method. [ABSTRACT FROM AUTHOR]

Body composition of 24 rural Beninese women was assessed in a pre- and a postharvest season by using skinfold-thickness measurements, bioelectrical-impedance analysis (BIA), and deuterium oxide (D2O) dilution. Fat mass assessed by D2O dilution was 12.3 ± 3.3 kg; by skinfold-thickness measurements, 13.8 ± 3.3 kg; and by BIA, 14.1 ± 2.9 kg. Fat mass assessed by D2O was significantly lower (P < 0.05) than fat mass assessed by the other two methods. Body weight in the postharvest season was 0.8 ± 1 .6 kg higher (P < 0.05) than during the preharvest season. All three methods demonstrated that there were no significant changes in fat mass but that fat-free mass increased significantly (P < 0.05) from pre- to postharvest season. [ABSTRACT FROM AUTHOR]

A comparison was made between the dose-to-the-mother deuterium-dilution method and the conventional test-weighing technique for determining human-milk intake in five exclusively breast-fed infants and in four breast-fed infants who received supplemental foods. After administration of ²H to the mothers human milk and infant urine were sampled over 14 d and analyzed for ²H:¹H ratios by gas-isotope-ratio mass spectrometry. Infant total body water was determined by l80 dilution. The test-weighing procedure was conducted for 5 d consecutively. The intake of human milk (mean ± SD) estimated by ²H dilution was 648 ± 63 g/d and estimated by test-weighing was 636 ± 84 g/d. The mean difference between the two methods was not significantly different from 0. The ²H-dilution and test-weighing techniques provide similar estimates of human-milk intake. [ABSTRACT FROM AUTHOR]

Deuterium dilution for the measurement of total body water (TBW) has been conducted using varying protocols for equilibration. We measured TBW from deuterium dilution in urine samples in twenty-eight subjects using three protocols: (1) early morning dosage without breakfast, measuring deuterium in a second voiding at 4h and 6h; (2) early morning dosage with breakfast with the same measurement times; (3) dosage as last consumption before overnight sleep, measuring deuterium in a second voiding at 10 h. Results were compared with TBW estimates from underwater weighing (UWW). Because UWW is an indirect measure of TBW, it is used as an independent reference method in order to compare only relative discrepancies between the two methods. TBW values in the fasted state were not significantly different from those obtained in the fed state. The urinary deuterium enrichment was higher at 4 h than at 6 h (resulting TBW differences: 0·6 (SD 0·4)I). At 4h and 6h, differences in TBW measurements from deuterium and densitometry were positively related to the amount of TBW, indicating incomplete equilibration in larger water compartments. At 10h no such relationship existed, indicating complete mixing of deuterium. It is concluded that 10h equilibration is preferable to the shorter 4h and 6h, for the determination of TBW. [ABSTRACT FROM PUBLISHER]

Although extensive studies have focused on carbon and water balance from aboveground measurements, the link between the belowground and aboveground processes deserves greater attention. In this context, the aim of this work was to assess the bi-directional feedback between whole-plant respiration and transpiration. The study was performed on 25 saplings of Sugi (Japanese cedar, Cryptomeria japonica D. Don), including dominant and suppressed individuals (total fresh weight ranging between 0.2 and 8.0 kg). During one week, the integrated water use (WU) was determined using the Deuterium dilution method. After this, the trees were uprooted and the root, stem, and leaf respiration were measured using incubation chambers and CO2 infrared sensors. The stem and root respiration followed a power response to mass (power exponent b < 1), implying a decline in mass-specific respiration with size. Conversely, the leaf respiration followed a near-linear increase with size (power exponent b ≈ 1), but was negatively affected by the stem density, indicating the hydraulic limitations of the leaf metabolism. The water use followed a power response with the tree size (b < 1), showing a decline in the transpiration per leaf mass with the tree size, but was also negatively correlated with the stem density. Our results indicate that dominant trees are more efficient in the use of water, and highlight the role of hydraulic limitations to leaf metabolism in suppressed trees. [ABSTRACT FROM AUTHOR]

Background: Maternal recall is most commonly used to determine exclusive breastfeeding rates. A gold standard stable isotope method is available which can determine intake of breast milk versus water from sources other than breast milk and thus objectively determine exclusive breastfeeding. The objectives of this study were to determine exclusive breastfeeding rates by both maternal recall and the objective stable isotope method and discuss the limitations and usefulness of the two methods. Methods: The study involved 100 mother-infant pairs in a peri-urban area in Durban, South Africa and study visits took place from July 2012 to September 2014. Maternal recall of exclusive breastfeeding was carried out using the World Health Organization's 24 hour recall of infant feeding and this was compared to the objective measurement of exclusive breastfeeding using the stable isotope technique at three time points: six weeks, three and 5.5 months. The objective measurements were carried out using two different cut off values for exclusive breastfeeding. Kappa analysis was used to quantify the relationship between maternal recall and results from the stable isotope technique for each mother-infant pair. Results: Over reporting of exclusive breastfeeding was common at the three different time points regardless of the cut off value used to assess exclusive breastfeeding by the stable isotope technique. Kappa analysis also revealed only slight or fair agreement (K < 0.24) between reported and measured exclusive breastfeeding at all time points. Conclusions: Maternal recall of exclusive breastfeeding is limited in accuracy and should be restricted to large scale epidemiological surveys. The more objective gold standard stable isotope method for measuring intake volumes of breast milk should be used to evaluate interventions with smaller representative samples. [ABSTRACT FROM AUTHOR]