Use of bioelectrical impedance analysis to assess body composition in rural Gambian children

Calibration of Bioelectrical Impedance Analysis Against Deuterium Dilution for Body Composition Assessment in Stunted Ugandan Children

BACKGROUND

BIA represents an important tool in body composition (BC) assessment, especially in low-income settings in which simple and affordable options are preferred. There is a particular need to measure BC in stunted children, in which cases population-specific BIA estimating equations are lacking.

OBJECTIVES

We calibrated an equation to estimate body composition from BIA using deuterium dilution (²H) as the criterion method in stunted children.

METHODS

We measured BC with ²H and performed BIA in stunted Ugandan children (n = 50). Multiple linear regression models were constructed to predict ²H-derived FFM from BIA-derived whole-body impedance and other relevant predictors. Model performance was expressed as adjusted R² and RMSE. Prediction errors were also calculated.

RESULTS

Participants were aged 16-59 mo, of whom 46% were girls, and their median (IQR) height-for-age z-score (HAZ) was -2.58 (-2.92 to -2.37) according to the WHO growth standards. Impedance index (height²/impedance measured at 50 kHz) alone explained 89.2% variation in FFM and had an RMSE of 583 g (precision error 6.5%). The final model contained age, sex, impedance index, and height-for-age z-score as predictors and explained 94.5% variation in FFM with an RMSE of 402 g (precision error 4.5%).

CONCLUSIONS

We present a BIA calibration equation for a group of stunted children with a relatively low prediction error. This may help evaluate the efficacy of nutritional supplementation in large-scale trials in the same population. J Nutr 20XX;xxx:xx.

The Role of Exercise on Cardiometabolic Profile and Body Composition in Youth with Type 1 Diabetes

Exercise has a direct positive effect on glycemic control by promoting insulin secretion from β-pancreatic islet-cells and by increasing skeletal muscle glucose uptake. The reduction in daily insulin needs and the optimization of glycemic control improves the patient's quality of life, self-esteem, mental wellness, as well as diabetes-related mobility and mortality. The aim of this study was to investigate the effect of physical activity in children and adolescents with type-1 diabetes (T1D) on diabetic control, cardiovascular, and biochemical profiles; hs-CRP; IL6; leptin; and adiponectin levels of the population under study. This is a prospective cross-sectional study that involved 80 participants (36 boys and 44 girls) with T1D, who were aged 6-21 years and who attended the Diabetes and Metabolism Clinic of the 2nd Pediatric Department, University of Athens, "P & A Kyriakou" Children's Hospital of Athens. Twenty (25%) children were above the 75th percentile regarding total levels of physical activity, while 40 (50%) and 20 (25%) were between the 25th and 75th percentile, as well as below the 25th percentile, respectively. In the group with an intermediate level of exercise, physical activity was negatively associated with the participant's family situation (traditional, single parent, grandparent, with others, or by himself/herself) (p = 0.013), ferritin (p = 0.031), lipoprotein(a) [Lp(a)] (p = 0.016), and squared leptin levels (p = 0.040). Whereas in the groups with extreme vs. no exercise there was a negative association with the number of daily glucose measurements (p = 0.047). However, in the group with non-vigorous exercise, physical activity was positively associated with high density lipoprotein-c (HDL-c) levels (p = 0.048). The findings of this study are indicative of the beneficial role of exercise on children and adolescents with T1D, which is achieved by primarily improving their cardiometabolic profile through the amelioration of lipid profile [HDL-c, Lp(a)] and leptin levels, as well as by reducing chronic systemic inflammatory response (ferritin) and ultimately decreasing the overall diabetes morbidity.

New bioelectrical impedance analysis equations for children and adolescents based on the deuterium dilution technique

BACKGROUND AND AIMS

Body composition in childhood is not only a marker of the prevalence of obesity, but it can also be used to assess associated metabolic complications. Bioelectrical impedance analysis (BIA) shows promise as an easy to use, rapid, and non-invasive tool to evaluate body composition. The objectives of this study were to: (a) develop BIA prediction equations to estimate total body water (TBW) and fat-free mass (FFM) in European children and early adolescents and to validate the analysis with the deuterium dilution as the reference technique and (b) compare our results with previously published paediatric BIA equations.

METHODS

The cohort included 266 healthy children and adolescents between 7 and 14 years of age, 46% girls, in five European countries: Bosnia and Herzegovina, Latvia, Montenegro, North Macedonia, and Portugal. TBW and FFM were the target variables in the developed regression models. For model development, the dataset was randomly split into training and test sets, in 70:30 ratio, respectively. Model tuning was performed with 10-fold cross-validation that confirmed the unbiased estimate of its performance. The final regression models were retrained on the whole dataset.

RESULTS

Cross-validated regression models were developed using resistance index, weight, and sex as the optimal predictors. The new prediction equations explained 87% variability in both TBW and FFM. Limits of agreement between BIA and reference values, were within ±17% of the mean, (-3.4, 3.7) and (-4.5, 4.8) kg for TBW and FFM, respectively. BIA FFM and TBW estimates were within one standard deviation for approximately 83% of the children. BIA prediction equations underestimated TBW and FFM by 0.2 kg and 0.1 kg respectively with no proportional bias and comparable accuracy among different BMI-for-age subgroups. Comparison with predictive equations from published studies revealed varying discrepancy rates with the deuterium dilution measurements, with only two being equivalent to the equations developed in this study.

CONCLUSIONS

The small difference between deuterium dilution and BIA measurements validated by Bland-Altman analysis, supports the application of BIA for epidemiological studies in European children using the developed equations.

Validation of bioelectrical impedance analysis for body composition assessment in children with obesity aged 8-14y

BACKGROUND & AIMS

The aim was to generate a predictive equation to assess body composition (BC) in children with obesity using bioimpedance (BIA), and avoid bias produced by different density levels of fat free mass (FFM) in this population.

METHODS

This was a cross-sectional validation study using baseline data from a randomized intervention trial to treat childhood obesity. Participants were 8 to 14y (n = 315), underwent assessments on anthropometry and BC through Air Displacement Plethysmography (ADP), Dual X-Ray Absorptiometry and BIA. They were divided into a training (n = 249) and a testing subset (n = 66). In addition, the testing subset underwent a total body water assessment using deuterium dilution, and thus obtained results for the 4-compartment model (4C). A new equation to estimate FFM was created from the BIA outputs by comparison to a validated model of ADP adjusted by FFM density in the training subset. The equation was validated against 4C in the testing subset. As reference, the outputs from the BIA device were also compared to 4C.

RESULTS

The predictive equation reduced the bias from the BIA outputs from 14.1% (95%CI: 12.7, 15.4) to 4.6% (95%CI: 3.8, 5.4) for FFM and from 18.4% (95%CI: 16.9, 19.9) to 6.4% (95% CI: 5.3, 7.4) for FM. Bland-Altman plots revealed that the new equation significantly improved the agreement with 4C; furthermore, the observed trend to increase the degree of bias with increasing FM and FFM also disappeared.

CONCLUSION

The new predictive equation increases the precision of BC assessment using BIA in children with obesity.

Cissus Quadrangularis enhances UCP1 mRNA, indicative of white adipocyte browning and decreases central obesity in humans in a randomized trial

Obesity is associated with the growth and expansion of adipocytes which could be decreased via several mechanisms. Cissus Quadrangularis (CQ) extract has been shown to reduce obesity in humans; however, its effect on human white adipocytes (hWA) has not been elucidated. This study aimed to investigate the effects of CQ on obesity, lipolysis, and browning of hWA. CQ treatment in obese humans significantly decreased waist circumference at week 4 and week 8 when compared with the baseline values (p < 0.05 all) and significantly decreased hip circumference at week 8 when compared with the baseline and week 4 values (p < 0.05 all). Serum leptin levels of the CQ-treated group were significantly higher at week 8 compared to baseline levels (p < 0.05). In hWA, glycerol release was reduced in the CQ-treated group when compared with the vehicle-treated group. In the browning experiment, pioglitazone, the PPAR-γ agonist, increased UCP1 mRNA when compared to vehicle (p < 0.01). Interestingly, 10, 100, and 1000 ng/ml CQ extract treatment on hWA significantly enhanced UCP1 expression in a dose-dependent manner when compared to pioglitazone treatment (p < 0.001 all). In conclusion, CQ decreased waist and hip circumferences in obese humans and enhanced UCP1 mRNA in hWA suggestive of its action via browning of hWA.

Muscle strength, muscle power and body composition in college-aged young women and men with Generalized Joint Hypermobility

The aim of this study was an evaluation of the musculoskeletal system in women and men with Generalized Joint Hypermobility (GJH). The study included 87 participants– 40 with Generalized Joint Hypermobility (aged 21.2 ±1.8 years) and 47 (aged 21.0 ±1.3 years) in the control group (CG). The study included the Beighton score, the measurements of body composition, muscle flexibility (Straight Leg Raise test, Popliteal Angle test, Modified Thomas Test), and the measurements of muscle strength and muscle power. T-test and Mann-Whitney U Test were applied to assess the differences between independent groups. The study showed that there were no significant differences (p>.05) in the assessed body composition and the muscle flexibility between both women and men with GJH and the participants in the CG. Under isokinetic conditions for the non-dominant lower extremity, men from the CG received significantly higher (p = .02) flexion peak torque at 180°/s angular velocity. Women from the CG received a statistically significantly lower (p = .04) F/E ratio at 180°/s velocity. Under isometric conditions for both women and men with GJH, there were no statistically significant differences (p>.05) in the maximum torques in knee extension and flexion compared to the CG. For women and men with GJH, the maximum power in the lower extremities and jumping ability were not significantly different (p>.05) compared to the CG participants. The body composition, muscle flexibility, muscle strength, and muscle power of adults with Generalized Joint Hypermobility did not differ compared to healthy participants. The fact that there are no differences does not exclude the efficacy of strength training in increasing levels of muscle strength and its impact on body posture and proprioception or coordination.

Skeletal muscle index determined by bioelectrical impedance analysis is a determinant of exercise capacity and a prognostic predictor in patients with congenital heart disease

BACKGROUND

Patients with congenital heart disease (CHD) reportedly have reduced exercise capacity. Underlying cardiac anatomy and a sedentary lifestyle are thought to be associated with exercise impairment. However, little has been reported regarding the relationship between quantitative body composition and exercise capacity. Bioelectrical impedance analysis (BIA) is a rapid and safe assessment method that has been widely used in clinical research. We hypothesized that bioelectrical impedance parameters are determinants of exercise capacity, and the skeletal muscle index (SMI) determined by BIA is a prognostic predictor in patients with CHD.

METHODS

We conducted a retrospective single-center study of 305 consecutive patients with CHD [median age, 26 years (range 12-60]; 48% males] admitted between 2014 and 2017. The BIA parameters were reviewed, including the edema index (EI, extracellular water to total body water ratio), SMI (skeletal muscle mass/height²), mineral index (MI, mineral mass/height²), percent body fat (%BF), and exercise capacity [peak oxygen uptake (peakVO₂)] via a cardiopulmonary exercise test.

RESULTS

The multivariate analysis revealed a significant correlation between peakVO₂ and EI (r=0.55) and peakVO₂ and SMI (r=0.49). The receiver operating characteristic curve analysis showed that the EI cut-off for peakVO₂<20ml/kg/min was 0.386 [area under the curve (AUC), 0.77; sensitivity, 0.67; specificity 0.76], and the SMI cut-off was 7.6kg/m² (AUC, 0.78; sensitivity, 0.76; specificity 0.75). Compared with patients who had biventricular morphology, patients with single ventricular morphology had a higher EI (mean, 0.381 vs. 0.387, respectively) and lower SMI (8.5 vs. 7.7, respectively), resulting in a lower peakVO₂ (27.1 vs. 20.8, respectively). The Kaplan-Meier analysis showed that a low SMI was associated with an increased risk of future heart failure-related admissions.

CONCLUSIONS

SMI determined by BIA is a determinant of exercise capacity and can be used as a prognostic predictor in patients with CHD.

Maternal and Infant Lipid-Based Nutritional Supplementation Increases Height of Ghanaian Children at 4-6 Years Only if the Mother Was Not Overweight Before Conception

BACKGROUND

Few studies have evaluated the long-term effects of nutritional supplementation during the first 1000 d of life. We previously reported that maternal and child lipid-based nutrient supplements (LNS) increased child length by 18 mo.

OBJECTIVE

The aim of this study was to examine the effects of LNS on later growth and body composition at 4-6 y of age.

DESIGN

This was a follow-up of children in the International Lipid-based Nutrient Supplements (iLiNS)-DYAD trial in Ghana. Women (n = 1320) at ≤20 weeks of gestation were randomly assigned to: 1) iron and folic acid during pregnancy and 200 mg calcium/d for 6 mo postpartum, 2) multiple micronutrients (1-2 RDA of 18 vitamins and minerals) during both periods, or 3) maternal LNS during both periods plus child LNS from 6 to 18 mo. At 4-6 y, we compared height, height-for-age z score (HAZ), and % body fat (deuterium dilution method) between the LNS group and the 2 non-LNS groups combined.

RESULTS

Data were available for 961 children (76.5% of live births). There were no significant differences between LNS compared with non-LNS groups in height [106.7 compared with 106.3 cm (mean difference, MD, 0.36; P = 0.226)], HAZ [-0.49 compared with -0.57 (MD = 0.08; P = 0.226)], stunting (< -2 SD) [6.5 compared with 6.3% (OR = 1.00; P = 0.993)], or % body fat [15.5 compared with 15.3% (MD = 0.16; P = 0.630)]. However, there was an interaction with maternal prepregnancy BMI (kg/m2) (P-interaction = 0.046 before correction for multiple testing): among children of women with BMI < 25 , LNS children were taller than non-LNS children (+1.1 cm, P = 0.017), whereas there was no difference among children of women with BMI ≥ 25 (+0.1 cm; P = 0.874).

CONCLUSIONS

There was no overall effect of LNS on height at 4-6 y in this cohort, which had a low stunting rate, but height was greater in the LNS group among children of nonoverweight/obese women. There was no adverse impact of LNS on body composition. This trial was registered at clinicaltrials.gov as NCT00970866.

Bioelectrical impedance analysis in the management of heart failure in adult patients with congenital heart disease

OBJECTIVE

The recognition of fluid retention is critical in treating heart failure (HF). Bioelectrical impedance analysis (BIA) is a well-known noninvasive method; however, data on its role in managing patients with congenital heart disease (CHD) are limited. Here, we aimed to clarify the correlation between BIA and HF severity as well as the prognostic value of BIA in adult patients with CHD.

DESIGN

This prospective single-center study included 170 patients with CHD admitted between 2013 and 2015. We evaluated BIA parameters (intra- and extracellular water, protein, and mineral levels, edema index [EI, extracellular water-to-total body water ratio]), laboratory values, and HF-related admission prevalence.

RESULTS

Patients with New York Heart Association (NYHA) functional classes III-IV had a higher EI than those with NYHA classes I-II (mean ± SD, 0.398 ± 0.011 vs 0.384 ± 0.017, P < .001). EI was significantly correlated with brain natriuretic peptide level (r = 0.51, P < .001). During the mean follow-up period of 7.1 months, Kaplan-Meier analysis showed that a discharge EI > 0.386, the median value in the present study, was significantly associated with a future increased risk of HF-related admission (HR = 4.15, 95% CI = 1.70－11.58, P < .001). A body weight reduction during hospitalization was also related to EI reduction.

CONCLUSIONS

EI determined using BIA could be a useful marker for HF severity that could predict future HF-related admissions in adult patients with CHD.

Validity of bioelectrical impedance analysis in predicting total body water and adiposity among Senegalese school-aged children

Introduction

Childhood obesity is currently a serious public health challenge in developing countries. Therefore, an accurate assessment of adiposity is required. The objective of this study was to validate BIA prediction equations for the assessment of total body water and adiposity or percentage of body fat for the first time in Senegalese school-aged children.

Methods

One-hundred-fifty-one (151) pupils who were 8–11 years old were randomly selected from four public schools in Dakar. The body composition measured by deuterium dilution method (DDM) was used as the reference method and compared to that predicted by BIA using a multi-frequency analyser. Stepwise backward multiple linear regression was performed to calculate TBW and %BF in a subsample, which were then validated in the rest of the sample. The Bland and Altman approach was used to assess the agreement between the two methods (bias and limits of agreement).

Results

FFM was higher in boys (24.6±6.9 kg) compared to girls (21.2±3.3 kg; P<0.001), and FM was lower in boys: 3.7 kg [0.9–26.4] compared to girls: 4.5 kg [1.7–22.7]. Overall, 11.3% of children presented excess adiposity (%BF >25% in boys, and >30% in girls) and 2.0% were obese according to WHO cut points for obesity (BMI z-score >+2.0). The equations developed were as follows: TBW = 0.376(Height²/Z₅₀)-0.470 (sex) +0.076(weight) +0.065(height)-2.28.

%BF = -1.10(height²/Z₅₀) +3.14(sex)+1.57(weight)-4.347. These specific equations showed good precision and a low and non-significant mean bias (0.11 kg, P = 0.279; and 0.19 kg, P = 0.764) for TBW and %BF, respectively.

Conclusion

The newly developed equations can be used as an accurate and alternative screening tool for the assessment of obesity among children in various settings.

Assessing the reliability of FTIR spectroscopy measurements and validity of bioelectrical impedance analysis as a surrogate measure of body composition among children and adolescents aged 8-19 years attending schools in Kampala, Uganda

Background

Accurate measurement of body composition in children and adolescents is important as the quantities of fat and fat-free mass have implications for health risk. The objectives of the present study were: to determine the reliability of Fourier Transform Infrared spectroscopy (FTIR) measurements and; compare the Fat Mass (FM), Fat Free Mass (FFM) and body fat percentage (%BF) values determined by bioelectrical impedance analysis (BIA) to those determined by deuterium dilution method (DDM) to identify correlations and agreement between the two methods.

Methods

A cross-sectional study was conducted among 203 children and adolescents aged 8–19 years attending schools in Kampala city, Uganda. Pearson product-moment correlation at 5% significance level was considered for assessing correlations. Bland Altman analysis was used to examine the agreement between of FTIR measurements and between estimates by DDM and BIA.. Reliability of measurements was determined by Cronbach’s alpha.

Results

There was good agreement between the in vivo D₂O saliva enrichment measurements at 3 and 4 h among the studied age groups based on Bland-Altman plots. Cronbach’s alpha revealed that measurements of D₂O saliva enrichment had very good reliability. For children and young adolescents, DDM and BIA gave similar estimates of FFM, FM, and %BF. Among older adolescents, BIA significantly over-estimated FFM and significantly under-estimated FM and %BF compared to estimates by DDM. The correlation between FFM, FM and %BF estimates by DDM and BIA was high and significant among young and older adolescents and for FFM among children.

Conclusions

Reliability of the FTIR spectroscopy measurements was very good among the studied population. BIA is suitable for assessing body composition among children (8–9 years) and young adolescents (10–14 years) but not among older adolescents (15–19 years) in Uganda. The body composition measurements of older adolescents determined by DDM can be predicted using those provided by BIA using population-specific regression equations.

Predictive validity of body fat percentage by bioimpedance compared with deuterium oxide dilution in Costa Rican schoolchildren

OBJECTIVE

The purpose of this study was to verify the validity of body fat percentage (BF%) by bioelectrical impedance analysis (BIA) in a sample of Costa Rican schoolchildren.

METHODS

The sample consisted of 52 male (mean age 8.1 ± 0.9 years) and 49 female (mean age 7.5 ± 1.0 years) schoolchildren. Deuterium oxide dilution was the reference method used as the "gold standard" to determine the fat mass (FM) expressed as BF%. Linear regression analyses and paired sample t-tests were used to test the association and mean differences between BIA and deuterium oxide dilution BF%. Concordance between BIA and deuterium oxide dilution BF% was determined by Lin's concordance correlation coefficient. Measurement of agreement between the two methods was analyzed using the Bland-Altman procedure.

RESULTS

Significant associations between BIA and deuterium oxide dilution BF% were found in males (R = 0.97, R²  = 0.95, P < .0001) and in females (R = 0.98, R²  = .96, P < .0001). The measurements of BF% (mean ± SD) were not significantly different between males (BIA 31.1 ± 7.6% vs. deuterium oxide dilution 31.0 ± 7.4%) and females (BIA 25.9 ± 7.9% vs. deuterium oxide dilution 26.3 ± 7.8%) by t-test. Lin's concordance correlation coefficient identified an almost perfect strength of agreement between males and females. Bland-Altman plots showed that the Bodystat measured similar BF% compared to the deuterium oxide dilution in both males and females.

CONCLUSIONS

BIA Bodystat presented high agreement with BF% measured by deuterium oxide dilution; therefore BIA Bodystat is recommended for estimating BF% in Costa Rican schoolchildren.

Body composition estimation in children and adolescents by bioelectrical impedance analysis: A systematic review

BACKGROUND

Bioelectrical impedance analysis (BIA) has commonly been used to assess the body composition of children and adolescents. BIA validation studies have found distinct correlation values with reference methods.

OBJECTIVES

To assess the reproducibility, correlation and mean differences in body composition estimated by BIA and reference methods, we systematically reviewed the literature in the pediatric population.

METHOD

The search for articles was conducted in March 2016 and was limited to articles published from 2005 to 2015 in the PubMed, Embase, EBSCO, Web of Science, Scopus and SciELO databases. Two reviewers independently performed data selection and extraction of studies that investigated the BIA validity, responsiveness, reliability and/or measurement error (reproducibility) to estimate body composition in children and adolescents with an average age ≤ 18 years.

RESULTS

The search produced 48 articles. Almost perfect reproducibility was found in the body fat percentage estimated by BIA, and there was almost perfect correlation between the BIA ratings and reference methods for fat mass and fat-free mass. Regarding component estimates, BIA underestimated the fat mass in both sexes.

CONCLUSIONS

The body fat percentage estimated by BIA exhibited almost perfect reproducibility. The fat mass and fat-free mass estimated by BIA correlated almost perfectly with the reference methods in both sexes. BIA underestimated the fat mass in both sexes.

Validation of two portable bioelectrical impedance analyses for the assessment of body composition in school age children

Background

Bioelectrical impedance analysis (BIA) is a convenient and child-friendly method for longitudinal analysis of changes in body composition. However, most validation studies of BIA have been performed on adult Caucasians. The present cross-sectional study investigated the validity of two portable BIA devices, the Inbody 230 (BIA_8MF) and the Tanita BC-418 (BIA_8SF), in healthy Taiwanese children.

Methods

Children aged 7–12 years (72 boys and 78 girls) were recruited. Body composition was measured by the BIA_8SF and the BIA_8MF. Dual X-ray absorptiometry (DXA) was used as the reference method.

Results

There were strong linear correlations in body composition measurements between the BIA_8SF and DXA and between the BIA_8MF and DXA. Both BIAs underestimated fat mass (FM) and percentage body fat (%BF) relative to DXA in both genders The degree of agreement in lean body mass (LBM), FM, and %BF estimates was higher between BIA_8MF and DXA than between BIA_8SF and DXA. The Lin’s concordance correlation coefficient (ρ_c) for LBM_8MF met the criteria of substantial to perfect agreement whereas the ρ_c for FM_8MF met the criteria of fair to substantial agreement. Bland-Altman analysis showed a clinically acceptable agreement between LBM measures by BIA_8MF and DXA. The limit of agreement in %BF estimation by BIA and DXA were wide and the errors were clinically important. For the estimation of ALM, BIA_8SF and BIA_8MF both provided poor accuracy.

Conclusions

For all children, LBM measures were precise and accurate using the BIA_8MF whereas clinically significant errors occurred in FM and %BF estimates. Both BIAs underestimated FM and %BF in children. Thus, the body composition results obtained using the inbuilt equations of the BIA_8SF and BIA_8MF should be interpreted with caution, and high quality validation studies for specific subgroups of children are required prior to field research.

Energetics and the immune system: Trade-offs associated with non-acute levels of CRP in adolescent Gambian girls

Background and objectives: The human immune system is an ever-changing composition of innumerable cells and proteins, continually ready to respond to pathogens or insults. The cost of maintaining this state of immunological readiness is rarely considered. In this paper we aim to discern a cost to non-acute immune function by investigating how low levels of C-reactive protein (CRP) relate to other energetic demands and resources in adolescent Gambian girls.

Methodology: Data from a longitudinal study of 66 adolescent girls was used to test hypotheses around investment in immune function. Non-acute (under 2 mg/L) CRP was used as an index of immune function. Predictor variables include linear height velocity, adiposity, leptin, and measures of energy balance.

Results: Non-acute log CRP was positively associated with adiposity (β = 0.16, P < 0.001, R² = 0.17) and levels of the adipokine leptin (β = 1.17, P = 0.006, R² = 0.09). CRP was also negatively associated with increased investment in growth, as measured by height velocity (β = −0.58, P < 0.001, R² = 0.13) and lean mass deposition β = −0.42, P = 0.005, R² = 0.08). Relationships between adiposity and growth explained some, but not all, of this association. We do not find that CRP was related to energy balance.

Conclusions and implications: These data support a hypothesis that investment in non-acute immune function is facultative, and sensitive to energetic resources and demands. We also find support for an adaptive association between the immune system and adipose tissue.

Validity of Four Commercial Bioelectrical Impedance Scales in Measuring Body Fat among Chinese Children and Adolescents

The aim of the study is to examine the validity in predicting body fat percentage (%BF) of different bioelectrical impedance (BIA) devices among Chinese children and adolescents. A total of 255 Chinese children and adolescents aged 9-19 years old participated in the study. %BF was assessed by BIA scales, namely, Biodynamics-310 (Model A), Tanita TBF-543 (Model B), Tanita BC-545 (Model C), and InBody 520 (Model D). Dual-energy X-ray absorptiometry (DXA) was used as the criterion measurement. Lin's concordance correlation coefficients of estimated %BF between Model A, Model B, Model C, and DXA showed poor agreements for both genders. Moderate agreements for %BF were found between DXA and Model D measurements. In boys, differences in %BF were found between DXA and Model B and Model C. No significant %BF differences were found between Model A, Model D, and DXA. However, the two BIA analyzers showed a significant positive correlation between the bias and average %BF between BIA and DXA. In girls, differences in %BF were observed between Model B, Model C, Model D, and DXA. Model A and DXA showed no significant differences of %BF; however, the bias and the average %BF between the BIA and DXA had a significant positive correlation. Using embedded equations in BIA devices should be validated in assessing the %BF of Chinese children and adolescents.

Bioelectric impedance analysis of body composition of children and adolescents with sickle cell anemia in Enugu, Nigeria

BACKGROUND

Body composition indices are widely used to evaluate growth and nutrition in children, particularly those with sickle cell anemia (SCA), who are known to have impaired growth, impaired skeletal maturation, and delayed puberty. The current study is aimed at determining the body composition of children with SCA.

METHODS

Consecutive selection of SCA children aged 6 to 18 years, who served as subjects and their age and gender matched children with HbAA (controls), selected using multi-stage systematic sampling. It was a cross-sectional descriptive study conducted at the pediatric hematology and oncology clinic. Bioelectric impedance analysis was used to determine the body composition parameters, including weight, body fat percentage (BFP), visceral fat percentage, body mass index (BMI), skeletal muscle percentage, and resting metabolic rate. Data were analyzed using SPSS 16.0 at P < 0.05.

RESULTS

One hundred and thirty-two subjects and controls respectively were studied. Subjects had lower body composition parameters compared with controls, with the older male subjects aged 10 to 18 years, having lower body composition indices (weight, height, BMI, and BFP) compared with controls. Visceral fat percentage was low in both subjects and controls.

CONCLUSIONS

Children with SCA, particularly the older males, have impaired body composition indices. There is a need to conduct further studies to determine the longitudinal aspects of growth as well as quantitative and qualitative assessment of nutritional intake in children with SCA, which will inform higher alimentation requirements for HbSS children as compared with HbAA individuals.

Ready-to-use supplementary food increases fat mass and BMI in Haitian school-aged children

BACKGROUND

In Haiti and other countries, large-scale investments in school feeding programs have been made with marginal evidence of nutrition outcomes.

OBJECTIVE

We aimed to examine the effectiveness of a fortified ready-to-use supplementary food (RUSF), Mamba, on reduced anemia and improved body composition in school-aged children compared to an unfortified cereal bar, Tablet Yo, and control groups.

METHODS

A cluster, randomized trial with children ages 3-13 y (n = 1167) was conducted in the north of Haiti. Six schools were matched and randomized to the control group, Tablet Yo group (42 g, 165 kcal), or Mamba group (50 g, 260 kcal, and >75% of the RDA for critical micronutrients). Children in the supplementation groups received the snack daily for 100 d, and all were followed longitudinally for hemoglobin concentrations, anthropometry, and bioelectrical impedance measures: baseline (December 2012), midline (March 2013), and endline (June 2013). Parent surveys were conducted at baseline and endline to examine secondary outcomes of morbidities and dietary intakes. Longitudinal regression modeling using generalized least squares and logit with random effects tested the main effects.

RESULTS

At baseline,14.0% of children were stunted, 14.5% underweight, 9.1% thin, and 73% anemic. Fat mass percentage (mean ± SD) was 8.1% ± 4.3% for boys and 12.5% ± 4.4% for girls. In longitudinal modeling, Mamba supplementation increased body mass index z score (regression coefficient ± SEE) 0.25 ± 0.06, fat mass 0.45 ± 0.14 kg, and percentage fat mass 1.28% ± 0.27% compared with control at each time point (P < 0.001). Among boys, Mamba increased fat mass (regression coefficient ± SEE) 0.73 ± 0.19 kg and fat-free mass 0.62 ± 0.34 kg compared with control (P < 0.001). Mamba reduced the odds of developing anemia by 28% compared to control (adjusted OR: 0.72; 95% CI: 0.57, 0.91; P < 0.001). No treatment effect was found for hemoglobin concentration.

CONCLUSION

To our knowledge, this is the first study to give evidence of body composition effects from an RUSF in school-aged children.

Body composition in Nepalese children using isotope dilution: the production of ethnic-specific calibration equations and an exploration of methodological issues

Background. Body composition is important as a marker of both current and future health. Bioelectrical impedance (BIA) is a simple and accurate method for estimating body composition, but requires population-specific calibration equations.

Objectives. (1) To generate population specific calibration equations to predict lean mass (LM) from BIA in Nepalese children aged 7–9 years. (2) To explore methodological changes that may extend the range and improve accuracy.

Methods. BIA measurements were obtained from 102 Nepalese children (52 girls) using the Tanita BC-418. Isotope dilution with deuterium oxide was used to measure total body water and to estimate LM. Prediction equations for estimating LM from BIA data were developed using linear regression, and estimates were compared with those obtained from the Tanita system. We assessed the effects of flexing the arms of children to extend the range of coverage towards lower weights. We also estimated potential error if the number of children included in the study was reduced.

Findings. Prediction equations were generated, incorporating height, impedance index, weight and sex as predictors (R² 93%). The Tanita system tended to under-estimate LM, with a mean error of 2.2%, but extending up to 25.8%. Flexing the arms to 90° increased the lower weight range, but produced a small error that was not significant when applied to children <16 kg (p 0.42). Reducing the number of children increased the error at the tails of the weight distribution.

Conclusions. Population-specific isotope calibration of BIA for Nepalese children has high accuracy. Arm position is important and can be used to extend the range of low weight covered. Smaller samples reduce resource requirements, but leads to large errors at the tails of the weight distribution.

Differing associations of BMI and body fat with asthma and lung function in children

BACKGROUND

Current evidence suggests that in children there is a significant, albeit weak, association between asthma and obesity. Studies generally use body mass index (BMI) in evaluating body adiposity, but there are limitations to its use.

METHOD

Children from a population-based study attending follow-up (age 11 years) were weighed, measured and had percent body (PBF) and truncal (PTF) fat assessed using bioelectrical impedance. They were skin prick tested and completed spirometry. Parents completed a validated respiratory questionnaire. Children were defined as normal or overweight according to BMI and PBF cut-offs. We tested the association between these adiposity markers with wheeze, asthma, atopy, and lung-function.

RESULTS

Six hundred forty-six children (339 male) completed follow-up. BMI z-score, PBF, and PTF were all positively associated with current wheeze (odds ratio [95% CI]: 1.27 [1.03, 1.57], P = 0.03; 1.05 [1.00, 1.09], P = 0.03; 1.04 [1.00, 1.08], P = 0.04, respectively). Similar trends were seen with asthma. However, when examining girls and boys separately, significant positive associations were found with PBF and PTF and asthma but only in girls (gender interaction P = 0.06 and 0.04, respectively). Associations between being overweight and wheezing and asthma were stronger when overweight was defined by PBF (P = 0.007, 0.03) than BMI (P > 0.05). Higher BMI was significantly associated with an increase in FEV(1) and FVC, but only in girls. Conversely, increasing body fat (PBF and PTF) was associated with reduced FEV(1) and FVC, but only in boys. No associations between adiposity and atopy were found.

CONCLUSION

All adiposity measures were associated with wheeze, asthma, and lung function. However, BMI and PBF did not have the same effects and girls and boys appear to be affected differently.

Bioelectrical impedance analysis to estimate body composition, and change in adiposity, in overweight and obese adolescents: comparison with dual-energy x-ray absorptiometry

Background

There is a need for a practical, inexpensive method to assess body composition in obese adolescents. This study aimed to 1) compare body composition parameters estimated by a stand-on, multi-frequency bioelectrical impendence (BIA) device, using a) the manufacturers’ equations, and b) published and derived equations with body composition measured by dual-energy x-ray absorptiometry (DXA) and 2) assess percentage body fat (%BF) change after a weight loss intervention.

Methods

Participants were 66 obese adolescents, mean age (SD) 12.9 (2.0) years. Body composition was measured by Tanita BIA MC-180MA (Tanita BIA₈) and DXA (GE-Lunar Prodigy). BIA resistance and reactance data at frequencies of 5, 50, 250 and 500 kHz, were used in published equations, and to generate a new prediction equation for fat-free mass (FFM) using a split-sample method. Approximately half (n = 34) of the adolescents had their body composition measured by DXA and BIA on two occasions, three to nine months apart.

Results

The correlations between FFM (kg), fat mass (kg) and %BF measured by BIA and DXA were 0.92, 0.93 and 0.78, respectively. The Tanita BIA₈ manufacturers equations significantly (P < 0.001) overestimated FFM (4.3 kg [-5.3 to 13.9]) and underestimated %BF (-5.0% [-15 to 5.0]) compared to DXA. The mean differences between BIA derived equations and DXA measured body composition parameters were small (0.4 to 2.1%), not significant, but had large limits of agreements (~ ±15% for FFM). After the intervention mean %BF loss was similar by both methods (~1.5%), but with wide limits of agreement.

Conclusion

The Tanita BIA₈ could be a valuable clinical tool to measure body composition at the group level, but is inaccurate for the individual obese adolescent.

Endocrine responses, weight change, and energy sparing mechanisms during Ramadan among Gambian adolescent women

OBJECTIVES

Ramadan fasting imposes a diurnal rather than a chronic energetic challenge. When Ramadan occurs during the agricultural season in subsistence populations, diurnal and chronic effects combine. The impact of layered energetic challenges on adolescent activity, metabolism, and body composition have not been quantified. This study compares the effects of a Ramadan (30 July-3 October 2009) and subsequent non-Ramadan (14 July-12 August 2010) agricultural season in 67 Gambian subsistence agriculturalist women between 14 and 20 years old.

METHODS

Researchers collected body composition, anthropometric, metabolic, and activity data. Metabolic hormones were measured in weekly urine (C-peptide of insulin) and serum (leptin). Energy expenditure was estimated from heart rate calibrated for oxygen consumption.

RESULTS

Participants lost more weight (Wald Chi-square 8.7, P < 0.01) and lean mass (Wald Chi-square 4.7, P < 0.05) in Ramadan than in the non-Ramadan agricultural season. Energy expenditure was lower (Wald Chi-square 11.2, P = 0.001) and there was a negative correlation between resting metabolic rate and energy expenditure in activity (R(2)  = 0.097, F = 5.366, P = 0.025) during Ramadan. Leptin and C-peptide were higher during Ramadan (Wald Chi-square 53.7, P < 0.001 and Wald Chi-square 15.0, P < 0.001).

CONCLUSIONS

Even using energy sparing behaviors, adolescent women enter negative energy balance when Ramadan and the agricultural season co-occur. Metabolic physiology shows a transient response to high glycemic index foods consumed at night. Older and larger individuals sustain greater losses during Ramadan.

Bioelectrical impedance analysis to estimate body composition in children and adolescents: a systematic review and evidence appraisal of validity, responsiveness, reliability and measurement error

Bioelectrical impedance analysis (BIA) is a practical method to estimate percentage body fat (%BF). In this systematic review, we aimed to assess validity, responsiveness, reliability and measurement error of BIA methods in estimating %BF in children and adolescents.We searched for relevant studies in Pubmed, Embase and Cochrane through November 2012. Two reviewers independently screened titles and abstracts for inclusion, extracted data and rated methodological quality of the included studies. We performed a best evidence synthesis to synthesize the results, thereby excluding studies of poor quality. We included 50 published studies. Mean differences between BIA and reference methods (gold standard [criterion validity] and convergent measures of body composition [convergent validity]) were considerable and ranged from negative to positive values, resulting in conflicting evidence for criterion validity. We found strong evidence for a good reliability, i.e. (intra-class) correlations ≥0.82. However, test-retest mean differences ranged from 7.5% to 13.4% of total %BF in the included study samples, indicating considerable measurement error. Our systematic review suggests that BIA is a practical method to estimate %BF in children and adolescents. However, validity and measurement error are not satisfactory.

Prediction of fat-free mass using bioelectrical impedance analysis in young adults from five populations of African origin

BACKGROUND/OBJECTIVES

Bioelectrical impedance analysis (BIA) is used in population and clinical studies as a technique for estimating body composition. Because of significant under-representation in existing literature, we sought to develop and validate predictive equation(s) for BIA for studies in populations of African origin.

SUBJECTS/METHODS

Among five cohorts of the Modeling the Epidemiologic Transition Study, height, weight, waist circumference and body composition, using isotope dilution, were measured in 362 adults, ages 25-45 with mean body mass indexes ranging from 24 to 32. BIA measures of resistance and reactance were measured using tetrapolar placement of electrodes and the same model of analyzer across sites (BIA 101Q, RJL Systems). Multiple linear regression analysis was used to develop equations for predicting fat-free mass (FFM), as measured by isotope dilution; covariates included sex, age, waist, reactance and height(2)/resistance, along with dummy variables for each site. Developed equations were then tested in a validation sample; FFM predicted by previously published equations were tested in the total sample.

RESULTS

A site-combined equation and site-specific equations were developed. The mean differences between FFM (reference) and FFM predicted by the study-derived equations were between 0.4 and 0.6 kg (that is, 1% difference between the actual and predicted FFM), and the measured and predicted values were highly correlated. The site-combined equation performed slightly better than the site-specific equations and the previously published equations.

CONCLUSIONS

Relatively small differences exist between BIA equations to estimate FFM, whether study-derived or published equations, although the site-combined equation performed slightly better than others. The study-derived equations provide an important tool for research in these understudied populations.

The adolescent transition under energetic stress: Body composition tradeoffs among adolescent women in The Gambia

BACKGROUND AND OBJECTIVES

Life history theory predicts a shift in energy allocation from growth to reproductive function as a consequence of puberty. During adolescence, linear growth tapers off and, in females, ovarian steroid production increases. In this model, acquisition of lean mass is associated with growth while investment in adiposity is associated with reproduction. This study examines the chronological and developmental predictors of energy allocation patterns among adolescent women under conditions of energy constraint.

METHODOLOGY

Fifty post-menarcheal adolescent women between 14 and 20 years old were sampled for weight and body composition at the beginning and end of 1 month in an energy-adequate season and 1 month in the subsequent energy-constrained season in a rural province of The Gambia.

RESULTS

Chronologically and developmentally younger adolescent girls gain weight in the form of lean mass in both energy-adequate and energy-constrained seasons, whereas older adolescents lose lean mass under conditions of energetic stress (generalized estimating equation (GEE) Wald chi-square comparing youngest tertile with older two tertiles 9.750, P = 0.002; GEE Wald chi-square comparing fast- with slow-growing individuals for growth rate 19.806, P < 0.001). When energy is limited, younger adolescents lose and older adolescents maintain fat (GEE Wald chi-square for interaction of age and season 6.568, P = 0.010; GEE Wald chi-square comparing fast- with slow-growing individuals for interaction of growth rate and season 7.807, P = 0.005).

CONCLUSIONS AND IMPLICATIONS

When energy is constrained, the physiology of younger adolescents invests in growth while that of older adolescent females privileges reproductively valuable adipose tissue.

Analyses of body composition charts among younger and older Chinese children and adolescents aged 5 to 18 years

BACKGROUND

Childhood obesity has become a major public health problem in China. The objective of this study was to examine the effect of age and sex on the relationship between fat-free mass (FFM) and fat mass (FM), fat-free mass index (FFMI) and fat mass index (FMI) in Chinese children using body composition chart analysis, and to compare the changing pattern with Caucasian and Japanese counterparts.

METHODS

A total of 1458 children (790 boys and 668 girls) between 5 and 18 years of age were studied to determine a body composition by bioelectrical impedance analysis. The relationship of FFM and FM, FFMI and FMI were delineated by body composition charts.

RESULTS

Different changing patterns in body composition were observed during 5-11y (younger age group), and 12-18y (older age group), with non-significant sex difference with FM and FMI for the younger age group and significant sex and age differences for the older age group. For the younger age group, simultaneous increase of FFM and FM was found in both genders. However, for the older age group, the increase in weight and BMI with age is largely due to the increment of FFM and FFMI in boys, and of FM and FMI in girls. In addition, different changing patterns in body composition exist between Chinese children and their Caucasian and Japanese counterparts, largely due to the higher fat mass component in Chinese subjects.

CONCLUSIONS

Our results indicate that age- and gender-related changing patterns of body composition in Chinese children may differ at different growth stage, and differ with those in Caucasian and Japanese children at the same age period. Such changing patterns should be considered when designing the intervention proposal for childhood obesity in China.

Segmental bioelectrical impedance analysis: an update

PURPOSE OF REVIEW

Bioelectrical impedance analysis is a popular, noninvasive and practical method for assessment of body composition. The last decade has seen the development of impedance analyzers designed to assess the composition of body segments as well as the whole body. This review outlines the theoretical basis for segmental impedance analysis, validity and use in practice.

RECENT FINDINGS

Segmental impedance analysis tends to underestimate fat-free mass and overestimate fat mass when compared to reference techniques, although the magnitude of these differences can be small. Performance is improved with population-specific prediction equations; algorithms in-built into instrument firmware should not be relied upon. Prediction of whole-body composition from the sum of the individual segments, although theoretically preferable, shows little advantage over whole body wrist to ankle impedance approaches. Prediction of appendicular skeletal muscle mass, although promising, requires further research. The use of measured impedance data directly as indices of composition, rather than for prediction, has not found extensive application in nutritional research despite its success in other fields.

SUMMARY

Segmental bioimpedance techniques have advanced substantially in recent years due to availability of simple-to-use analyzers and simplified measurement protocols. The method has been well validated and increasingly adopted in nutritional and clinical practice. Segmental impedance, like conventional whole body impedance approaches, provides indirect prediction of body composition whose accuracy is yet to achieve that of reference techniques such as magnetic reference imaging. This lack of accuracy, however, is outweighed by the method's practicality of use in many settings.

Nutritional supplementation during pregnancy and offspring cardiovascular disease risk in The Gambia

BACKGROUND

Maternal nutritional intake during pregnancy may have important consequences for long-term health in offspring.

OBJECTIVE

The objective was to follow up the offspring in 2 randomized trials of nutrient supplementation during pregnancy to investigate the effect on cardiovascular disease (CVD) risk in offspring.

DESIGN

We recruited offspring born during 2 trials in The Gambia, West Africa. One trial provided protein-energy-dense food supplements (1015 kcal and 22 g protein/d) to pregnant (intervention, from 20 wk gestation until delivery) or lactating (control, for 20 wk from birth) women and was randomized at the village level. The second was a double-blind, individually randomized, placebo-controlled trial of calcium supplementation (1.5 g/d), which was also provided from 20 wk gestation until delivery.

RESULTS

Sixty-two percent (n = 1267) of children (aged 11-17 y) born during the protein-energy trial were recruited and included in the analysis, and 64% (n = 350) of children (aged 5-10 y) born during the calcium trial were recruited and included in the analysis. Fasted plasma glucose was marginally lower in children born to mothers receiving protein-energy supplements during pregnancy than in those children of the lactating group (adjusted mean difference: -0.05 mmol/L; 95% CI: -0.10, -0.001 mmol/L). There were no other differences in CVD risk factors, including blood pressure, body composition, and cholesterol, between children born to intervention and control women from the protein-energy trial. Maternal calcium supplementation during pregnancy was unrelated to offspring blood pressure.

CONCLUSION

These data suggest that providing supplements to pregnant women in the second half of pregnancy may have little effect on the CVD risk of their offspring, at least in this setting and at the ages studied here. This trial was registered at www.controlled-trials.com as ISRCTN96502494.

Effect of maternal calcium supplementation on offspring blood pressure in 5- to 10-y-old rural Gambian children

BACKGROUND

Evidence suggests that increased maternal calcium intake during pregnancy may result in lower offspring blood pressure, prompting calls for more robust data in this field, particularly in settings of habitually low calcium intake.

OBJECTIVE

The objective was to investigate the effect of maternal calcium supplementation on blood pressure in offspring by recruiting children born after a randomized, double-blind, placebo-controlled trial of calcium supplementation during pregnancy.

DESIGN

Children (n = 389) from a rural area of The Gambia (mean age: 7.4 ± 1.2 y; range: 5-10 y), whose mothers received a calcium supplement (1500 mg Ca/d from 20 wk of gestation until delivery) or placebo, were followed up in West Africa. Blood pressure was assessed under standardized conditions with use of the Omron 705IT automated oscillometric device (Morton Medical Ltd, London, United Kingdom), and anthropometric and body composition (bioelectrical impedance) measurements were also made.

RESULTS

The analysis was restricted to 350 children born at term, which represented 64% of original trial births. There was no difference in systolic (adjusted mean difference: -0.04 mm Hg; 95% CI: -1.78, 1.69 mm Hg) or diastolic (adjusted mean difference: 0.25 mm Hg; 95% CI: -1.27, 1.77 mm Hg) blood pressure between children whose mothers had received calcium and those who received placebo. No interaction between childhood body mass index (in kg/m(2); mean: 14.0) and maternal calcium supplementation was observed in this study.

CONCLUSION

Calcium supplementation in the second half of pregnancy in Gambian women with very low habitual calcium intakes may not result in lower offspring blood pressure at 5-10 y of age.

Prediction of fatness by standing 8-electrode bioimpedance: a multiethnic adolescent population

The objective of this study was to validate an 8-electrode bioimpedance analysis (BIA(8)) device (BC-418; Tanita, Tokyo, Japan) for use in populations of European, Maori, Pacific Island, and Asian adolescents. Healthy adolescents (215 M, 216 F; 129 Pacific Island, 120 Asian, 91 Maori, and 91 European; age range 12-19 years) were recruited by purposive sampling of high schools in Auckland, New Zealand. Weight, height, sitting height, leg length, waist circumference, and whole-body impedance were measured. Fat mass (FM) and fat-free mass (FFM) derived from the BIA(8) manufacturer's equations were compared with measurements by dual-energy X-ray absorptiometry (DXA). DXA-measured FFM was used as the reference to develop prediction equations based on impedance. A double cross-validation technique was applied. BIA(8) underestimated FM by 2.06 kg (P < 0.0001) and percent body fat (%BF) by 2.84% (P < 0.0001), on average. However, BIA(8) tended to overestimate FM and %BF in lean and underestimate FM and %BF in fat individuals. Sex-specific equations developed showed acceptable accuracy on cross-validation. In the total sample, the best prediction equations were, for boys: FFM (kg) = 0.607 height (cm)(2)/impedance ( ohm) + 1.542 age (y) + 0.220 height (cm) + 0.096 weight (kg) + 1.836 ethnicity (0 = European or Asian, 1 = Maori or Pacific) - 47.547, R(2) = 0.93, standard error of estimate (SEE) = 3.09 kg; and, for girls: FFM (kg) = 0.531 height (cm)(2)/impedance ( ohm) + 0.182 height (cm) + 0.096 weight (kg) + 1.562 ethnicity (0 = non-Pacific, 1 = Pacific) - 15.782, R(2) = 0.91, SEE = 2.19 kg. In conclusion, equations for fatness estimation using BIA(8) developed for our sample perform better than reliance on the manufacturer's estimates. The relationship between BIA and body composition in adolescents is ethnicity dependent.

Validation of BIA in obese children and adolescents and re-evaluation in a longitudinal study

Decrease in fat mass (FM) is a one of the aims of pediatric obesity treatment; however, measurement techniques suitable for routine clinical assessment are lacking. The objective of this study was to validate whole-body bioelectrical impedance analysis (BIA; TANITA BC-418MA) against the three-component (3C) model of body composition in obese children and adolescents, and to test the accuracy of our new equations in an independent sample studied longitudinally. A total of 77 white obese subjects (30 males) aged 5-22 years, BMI-standard deviation score (SDS) 1.6-3.9, had measurements of weight, height (HT), body volume, total body water (TBW), and impedance (Z). FM and fat-free mass (FFM) were calculated using the 3C model or predicted from TANITA. FFM was predicted from HT(2)/Z. This equation was then evaluated in 17 other obese children (5 males) aged 9-13 years. Compared to the 3C model, TANITA manufacturer's equations overestimated FFM by 2.7 kg (P < 0.001). We derived a new equation: FFM = -2.211 + 1.115 (HT(2)/Z), with r(2) of 0.96, standard error of the estimate 2.3 kg. Use of this equation in the independent sample showed no significant bias in FM or FFM (mean bias 0.5 +/- 2.4 kg; P = 0.4), and no significant bias in change in FM or FFM (mean bias 0.2 +/- 1.8 kg; P = 0.7), accounting for 58% (P < 0.001) and 55% (P = 0.001) of the change in FM and FFM, respectively. Our derived BIA equation, shown to be reliable for longitudinal assessment in white obese children, will aid routine clinical monitoring of body composition in this population.

Body composition determination by bioimpedance: an update

PURPOSE OF REVIEW

To review various methods for measuring body composition by bioimpedance and their limitations, as well as available impedance meters, including body fat analyzers for home use.

RECENT FINDINGS

Bioimpedance spectroscopy, which requires multifrequency impedance meters, is preferable for fluid volume measurements, especially extracellular fluid, whereas bioimpedance analysis at 50 kHz is more widely used for measuring fat-free mass. A method for using bioimpedance spectroscopy equations with 50 kHz impedance meters has been recently proposed and successfully tested. Low cost foot-to-foot impedance meters (body fat analyzers) with plantar electrodes on a body scale, that are easy and fast to use, have been compared with medical impedance meters and with dual X-ray absorptiometry measurements and found reasonably accurate, except for individuals with very low or high BMI.

SUMMARY

Body composition by bioimpedance is gaining acceptance in nutrition, hemodialysis, gerontology and sports medicine. Body fat analyzers that have been validated by comparison with dual x-ray absorptiometry could be useful to general practitioners, nutritionists and cardiologists.

Challenges of nutritional assessment in pediatric ICU

PURPOSE OF REVIEW

The nutritional assessment of children in the pediatric ICU is unique in view of the metabolic changes of the underlying disease. This review addresses the use and limitations of anthropometry and laboratorial and body composition markers in the diagnosis of the nutritional status of such patients.

RECENT FINDINGS

The presence of inflammatory activity leads to body composition changes (lean mass reduction) and undernutrition. Nutritional assessment in pediatric ICU must prioritize anthropometric and laboratory markers that can differentiate body composition to detect specific macronutrient and micronutrient deficiencies and assessment of the inflammatory activity.

SUMMARY

Nutritional assessment is one of the main aspects of the pediatric intensive care patient and is the most important tool to avoid hospital undernutrition. There is currently no gold standard for nutritional assessment in the pediatric ICU. The results of anthropometric and laboratory markers must be jointly analyzed, but individually interpreted according to disease and metabolic changes, in order to reach a correct diagnosis of the nutritional status and to plan and monitor the nutritional treatment.

Improving literacy about energy-related issues: the need for a better understanding of the concepts behind energy intake and expenditure among adolescents and their parents

Despite the need for effective obesity prevention strategies, little research has assessed adolescents' knowledge about basic concepts of energy intake, expenditure, and balance. Using data from 349 adolescent-caregiver pairs (recruited from Minneapolis/St Paul, MN metro region, 2006-2007), cross-sectional linear regression was used to assess adolescent and parental knowledge related to energy intake and expenditure as a predictor of adolescent weight-related behaviors and outcomes. Findings indicated that knowledge related to energy intake and expenditure was highly variable, with a substantial proportion of participants (particularly adolescents) lacking knowledge on a range of concepts. Adolescent knowledge was positively associated with moderate physical activity and negatively associated with television viewing (P<0.05), but it was not associated with sweetened beverage consumption, fast food intake, weight status, and/or body composition. Although overall parental knowledge was a significant predictor of adolescent knowledge (P<0.01), parent-child agreement on individual items was poor. As adolescents age, low literacy in this area may set the stage for poor decision-making related to energy balance and healthy weight maintenance. However, in that knowledge was not a significant predictor of various weight-related outcomes, these and other findings suggest that purely education-based health promotion strategies are insufficient to initiate long-term healthful behavior change. Educational strategies may be effective when combined with those also targeting familial, social, and environmental influences. The examination of interactive effects between individual-level and environmental influences on health behavior is an important area for future obesity-related research.

Dietary supplementation of rural Gambian women during pregnancy does not affect body composition in offspring at 11-17 years of age

Fetal nutrition is thought to be an important determinant of later disease risk, although evidence from randomized-controlled trials in humans is lacking. We followed children born during a protein-energy supplementation trial to investigate to what extent this maternal supplement, which improved birth weight, influenced offspring body composition in adolescence. Subjects were 1270 Gambian children (659 boys, 611 girls) aged 11-17 y whose mothers had participated in the original cluster-randomized trial and had received the supplement during pregnancy (intervention) or postpartum (control). Basic anthropometry was measured using standard techniques and fatness was assessed by bioelectrical impedance analysis and population-specific prediction equations. For boys, mean body fat was 12.6% for both intervention and control groups. Mean trunk fat was 11.9% in the intervention group and 12.0% in the control. Intervention girls had a mean body fat of 19.5% and trunk fat of 15.2%; for control girls, it was 19.3 and 14.8%, respectively. BMI, body fat, trunk fat, fat mass index, and fat-free mass index did not differ for either sex when analyzed with generalized estimating equations adjusted for age, maternal height, maternal parity, location, season of birth, and menarche in females. Neither infant-attained size nor the onset of menarche were affected by maternal supplementation. These findings suggest that protein-energy supplements to pregnant women, compared with lactating women, do not affect offspring body composition during adolescence.

Conference on "Multidisciplinary approaches to nutritional problems". Postgraduate Symposium. Exploiting dietary supplementation trials to assess the impact of the prenatal environment on CVD risk

Animal studies have demonstrated that altering the maternal diet during pregnancy affects offspring disease risk. Data from human subjects on the early-life determinants of disease have been derived primarily from birth-weight associations; studies of the impact of the maternal diet are scarce and inconsistent. Investigating CVD risk factors in the offspring of women who have participated in maternal supplementation trials provides a useful resource in this research field, by virtue of employing an experimental design (as compared with observational studies). To date, follow-up studies have been published only for a small number of trials; these trials include the impact of maternal protein-energy, multiple-micronutrient and Ca supplementation on offspring disease risk. In Nepal maternal micronutrient supplementation has been shown to be associated with lower offspring systolic blood pressure at 2 years of age. Data from Guatemala on a pre- and postnatal protein-energy community intervention have suggested long-term improvements in fasting glucose and body composition but not in blood pressure. In The Gambia no association has been found between prenatal protein-energy supplementation and markers of CVD risk including body composition, blood pressure and fasting glucose and insulin in childhood and adolescence. Little evidence of an effect of maternal Ca supplementation on offspring blood pressure has been demonstrated in four trials, although the risk of high systolic blood pressure was found to be reduced in one trial. The present paper reviews the current evidence relating maternal nutritional supplementation during pregnancy to offspring CVD risk and explores the potential explanations for the lack of association.

Maternal protein-energy supplementation does not affect adolescent blood pressure in The Gambia

Background Birthweight, and by inference maternal nutrition during pregnancy, is thought to be an important determinant of offspring blood pressure but the evidence base for this in humans is lacking data from randomized controlled trials.

Methods The offspring from a maternal prenatal protein-energy supplementation trial were enrolled into a follow-up study of chronic disease risk factors including blood pressure. Subjects were 11–17 years of age and blood pressure was measured in triplicate using an automated monitor (Omron 705IT). One-thousand two-hundred sixty seven individuals (71% of potential participants) were included in the analysis.

Results There was no difference in blood pressure between those whose mothers had consumed protein-energy biscuits during pregnancy and those whose mothers had consumed the same supplement post-partum. For systolic blood pressure the intention-to-treat regression coefficient was 0.46 (95% CI: –1.12, 2.04). Mean systolic blood pressure for control children was 110.2 (SD ± 9.3) mmHg and for intervention children was 110.8 (SD ± 8.8) mmHg. Mean diastolic blood pressure for control children was 64.7 (SD ± 7.7) mmHg and for intervention children was 64.6 (SD ± 7.6) mmHg.

Conclusions We have found no association between maternal prenatal protein-energy supplementation and offspring blood pressure in adolescence amongst rural Gambians. We found some evidence to suggest that offspring body composition may interact with the effect of maternal supplementation on blood pressure.