Pediatric Applications of BIA

Nichols J, Going S, Loftin M, Stewart D, Nowicki E, Pickrel J.

San Diego State University, San Diego, CA.

The purpose of this study was to compare fat-free mass (FFM) and percent body fat determined by two bio-electrical impedance analysis (BIA) instruments against criterion estimates determined by dual-energy x-ray absorptiometry (DXA) in a multi-racial/ethnic sample of adolescent girls. BIA was assessed in 151 girls (n=51 African-American; n=45 Hispanic; n=55 Caucasian; age 12.2 +/- 1.2 yr) using the RJL Quantum II and the American Weights and Measures Body-Comp Scale (BCS). Percent body fat determined by BIA was significantly related to that determined by DXA (R(2)=0.87, SEE=2.8% for RJL vs DXA, P<0.0001; R(2)=0.71, SEE=4.4% for BCS vs DXA, P<0.0001). The agreement between DXA and BIA for FFM was also significant (R(2)=0.91, SEE=0.03 kg for RJL, P <0.0001; R(2)=0.79, SEE=0.04 kg for BCS, P <0.0001). The BCS overestimated FFM by 2.7 kg (P<0.0001) and underestimated percent body fat by over 4% (P<0.001). There were no differences in percent body fat between DXA and the RJL, and although the RJL significantly overestimated FFM, the absolute difference was <1 kg. Within each ethnic group, the RJL instrument more closely estimated FFM and percent body fat than did the BCS. Although both BIA instruments compared favorably with DXA, the RJL had better stability and accuracy than the BCS, for both the total sample and for the three ethnic groups. Considering its relatively low cost and minimal time required for technical training, BIA is a useful and appropriate technique for assessing body composition in adolescent girls.

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J Nutr. 2001 May;131(5):1589S-95S.

Ellis KJ.

Body Composition Laboratory, U.S. Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center, Baylor College of Medicine, Houston, TX 77030, USA.

This article provides an overview of the present status of in vivo body composition methodologies that have potential for use in field studies. The methods are divided into four general categories: anthropometric indices and skinfold, body volume measurements, body water measurements including bioelectrical methods, and imaging techniques. Among the newest technologies are air-displacement plethysmography, three-dimensional photonic scanning, multifrequency bioelectrical impedance spectroscopy and whole-body tomography using electrical impedance and magnetic induction. These newer approaches are compared with the established reference methods. The advantages and limitations of each technique as a field method are presented relative to the corresponding concepts of an ideal method.

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Am J Clin Nutr. 2006 Jan;83(1):65-9.

Mok E, Béghin L, Gachon P, Daubrosse C, Fontan JE, Cuisset JM, Gottrand F, Hankard R.

INSERM Centre D’Investigation Clinique 9202, Assistance Publique-Hôpitaux de Paris, Hôpital Robert Debré, Paris, France.

BACKGROUND: Duchenne muscular dystrophy (DMD) is often associated with obesity, which worsens the handicap early in the course of the disease. Nutritional assessment, however, can be difficult and often misleading in DMD. OBJECTIVE: Two methods of estimating body composition in DMD, skinfold-thickness (ST) measurement and bioelectrical impedance analysis (BIA), were compared with a reference method, labeled water dilution (WD). DESIGN: Body composition was estimated by using ST measurements and BIA (50 kHz, 800 mAmp), as well as the WD method (1 mL H2(18)O/kg) in 11 DMD patients with a mean (+/-SD) age of 10.0 +/- 2.5 y. RESULTS: When compared with the WD method, ST measurement significantly (P < 0.01) overestimated fat-free mass (FFM) (mean +/- SD ST: 24.5 +/- 5.9 kg; mean +/- SD WD: 18.2 +/- 2.5 kg), which led to an underestimation of the percentage of fat mass (%FM) (ST: 23.3 +/- 10.4%; WD: 40.1 +/- 17.1%; P < 0.05). In contrast, estimates obtained with BIA (FFM: 21.5 +/- 4.5 kg; %FM: 31.3 +/- 13.9%) did not differ from those obtained with WD. The difference from the reference method was less for BIA (mean: 3.3 kg; 95% CI: 0.8, 4.9 kg) than for ST (6.3 kg; 2.2, 8.6 kg). WD and BIA defined 73% and 55%, respectively, of the children as obese (%FM associated with body mass index cutoffs for obesity), whereas ST measurements defined 9% as obese (P < 0.01). CONCLUSIONS: Body-composition estimates by BIA are closer to those by WD than are those by ST measurement. Early detection of fat accumulation and longitudinal monitoring of nutritional care are 2 relevant applications of BIA to prevent obesity and hence lessen the burden of DMD.

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An Pediatr (Barc). 2004 Jul;61(1):23-31.

Casanova Romÿn M, Rodríguez Ruiz I, Rico de Cos S, Casanova Bellido M.

Servicio de Pediatría, Hospital Universitario de Puerto Real, Cátedra de Pediatría, Facultad de Medicina de Cádiz, Puerto Real, Cádiz, Spain. mcasanovar@telefonica.net

BACKGROUND: Interest in the study of body composition in childhood is increasing. Bioelectrical impedance analysis (BIA) is an accurate and reliable method. OBJECTIVES: To determine anthropometric parameters, fat-free body mass and fat body mass using BIA and anthropometry, and to establish their relationship. MATERIAL AND METHOD: A total of 365 healthy children (188 boys, 177 girls) aged 6.0 to 14.9 years were studied. Weight, height, arm circumference, skinfolds (bicipital, tricipital, subscapular and suprailiac) and bioelectrical parameters were measured. Body density was calculated from the four skinfold measurements using Brook’s formula. Bioelectrical impedance was measured with a BIA-101 S (RJL Systems) using a fixed frequency (50 kHz). Fat-free body mass from BIA was calculated using Deurenberg’s equation (FFM = 0.82 x height2/resistance). RESULTS: We present the mean, standard deviation and 3rd, 5th, 10th, 25th, 50th, 75th, 90th, 95th and 97th percentiles of anthropometric variables and fat mass and fat-free mass estimated using BIA. Correlations were found between fat-free mass estimated using BIA and anthropometric variables. The reliability of BIA in estimating fat mass was assessed with intraclass correlation coefficients, which were excellent (0.948 in boys, and 0.945 in girls). CONCLUSIONS: BIA is an easy, low-cost, and highly reliable method, making it a useful technique for studying human body composition. This method shows excellent correlation with anthropometric variables.

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Phys Ther. 1993 May;73(5):320-8.

Wu YT, Nielsen DH, Cassady SL, Cook JS, Janz KF, Hansen JR.

Physical Therapy Graduate Program, University of Iowa, Iowa City 52242.

BACKGROUND AND PURPOSE. The reliability and validity of measurements obtained with two bioelectrical impedance analyzers (BIAs), an RJL Systems model BIA-103 and a Berkeley Medical Research BMR-2000, were investigated using the manufacturers’ prediction equations for the assessment of fat-free mass (FFM) (in kilograms) in children and adolescents. SUBJECTS. Forty-seven healthy children and adolescents (23 male, 24 female), ranging in age from 8 to 20 years (mean = 12.1, SD = 2.3), participated. METHODS. In the context of a repeated-measures design, the data were analyzed according to gender and maturation (Tanner staging). Hydrostatic weighing (HYDRO) and Lohman’s Siri age-adjusted body density prediction equation served as the criteria for validating the BIA-obtained measurements. RESULTS. High intraclass correlation coefficients (ICC > or = .987) demonstrated good test-retest (between-week) measurement reliability for HYDRO and both BIA methods. Between-method (HYDRO versus BIA) correlation coefficients were high for both boys and girls (r > or = .97). The standard errors of estimate (SEEs) for FFM were slightly larger for boys than for girls and were consistently smaller for the RJL system than for the BMR system (RJL SEE = 1.8 kg for boys, 1.3 kg for girls; BMR SEE = 2.4 kg for boys, 1.9 kg for girls). The coefficients of determination were high for both BIA methods (r2 > or = .929). Total prediction errors (TEs) for FFM showed similar between-method trends (RJL TE = 2.1 kg for boys, 1.5 kg for girls; BMR TE = 4.4 kg for boys, 1.9 kg for girls). DISCUSSION AND CONCLUSION. This study demonstrated that the RJL BIA with the manufacturer’s prediction equations can be used to reliably and accurately assess FFM in 8- to 20-year-old children and adolescents. The prediction of FFM by the BMR system was acceptable for girls, but significant overprediction of FFM for boys was noted.

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J Am Soc Nephrol. 2006 Jan;17(1):285-93. Epub 2005 Nov 30.

Morgenstern BZ, Wühl E, Nair KS, Warady BA, Schaefer F.

Division of Pediatric Nephrology, Phoenix Children’s Hospital, 1919 East Thomas Road, Phoenix, AZ 85016, USA. bmorgenstern@mayo.edu

Accurate estimation of total body water (TBW) is a critical component of dialysis prescription in peritoneal dialysis (PD). Gold-standard isotope dilution techniques are laborious and costly; therefore, anthropometric prediction equations that are based on height and weight are commonly used to estimate TBW. Equations have been established in healthy populations, but their validity is unclear in children who undergo PD, in whom altered states of hydration and other confounding alterations in normal physiology, particularly retarded growth and pubertal delay, may exist. TBW was measured by heavy water (H2O18 or D2O) dilution in 64 pediatric patients who were aged 1 mo to 23 yr and receiving chronic PD in the United States and Germany to establish and validate population-specific anthropometric TBW prediction equations and to compare the predictive power of these equations with formulas that have been established in healthy children. The best-fitting equations are as follows: For boys, TBW = 0.10 x (HtWt)0.68 – 0.37 x weight; for girls, TBW = 0.14 x (HtWt)0.64 – 0.35 x weight. The height x weight parameter also predicts body surface area (BSA). These equations can be simplified, with slightly less precision, to the following: For boys, TBW = 20.88 x BSA – 4.29; for girls, TBW = 16.92 x BSA – 1.81. TBW is predicted without systematic deviations and equally well in boys and girls, North American and European, obese and nonobese, growth-retarded and normally sized, and pre- and postpubertal children. In contrast, previous anthropometric equations that were derived from healthy children systematically overpredicted TBW and were less precise in this pediatric PD population. In summary, a new set of anthropometric TBW prediction equations that are suited specifically for use in pediatric PD patients have been provided.

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J Physiol Anthropol Appl Human Sci. 2004 Mar;23(2):35-9.

Masuda T, Komiya S.

Department of Child Education, Nakamura-Gakuen Junior College, Japan. Masuda@nakamura-u.ac.jp

Total body water (TBW) measured by isotope dilution techniques can be used to assess body composition safely and accurately in children. Unfortunately, this method is not readily available for most research projects, particularly when working with large groups of people, because the equipment is complicated and highly specialized. Bioelectrical impedance (BI) method is a simple, quick, and inexpensive method for the assessment of total body water (TBW). In Japanese child population, however, a lack of prediction equations is a problem to determine TBW. The purpose of this study was to determine the prediction equation for TBW determination in Japanese children using the isotope dilution technique as the reference method. Seventy Japanese children (39 boys, 31 girls) with ages ranging between 3 and 6 years participated in this study. They were randomly divided into the validation group (26 boys, 20 girls) and cross-validation group (13 boys, 11 girls). In a forward stepwise regression analysis, 96% of the variability in TBW measured by deuterium oxide (D(2)O) dilution could be predicted by the following equation: TBW(kg)=0.149 x Resistance Index (Stature(2)/resistance, cm(2)/Omega)+0.244 x Weight(kg)+0.460 x Age(y)+0.501 x Sex (boy=1, girl=0)+1.628, with a root mean square error (RMSE) of 0.440 kg in the validation group. This equation predicted TBW in the cross-validation group with R(2)=0.946 and a pure error (PE)=0.400 kg TBW. Hence, this equation should be applicable for predicting TBW in Japanese children aged 3-6 y.

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Acta Diabetol. 2003 Oct;40 Suppl 1:S270-3.

Pietrobelli A, Peroni DG, Faith MS.

Pediatric Unit, School of Medicine, University of Verona Policlinic “GB Rossi”, Via delle Menegone 10, I-37134, Verona, Italy. angpie@tin.it

There is currently much interest in the subject of pediatric obesity. Accurate measures of body composition are required given the potential influence of variables such as growth, metabolic rate, physical activity, and physical fitness. Because boys and girls have a different growth pattern, gender is a fundamental consideration when measuring children and assessing body composition. The central aim of this paper is to review methods of pediatric body composition assessment that can provide new insights for clinical practice.

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Semin Fetal Neonatal Med. 2007 Feb;12(1):87-91. Epub 2006 Dec 14.

Ellis KJ.

Baylor College of Medicine, USDA/ARS Children’s Nutrition Research Center, 1100 Bates St, Houston, TX 77030, USA. kellis@bcm.tmc.edu

A better understanding of the nutritional needs of both healthy and sick infants is important. Not only does too much or too little nutrition during early life have long-term effects on health, but periods of rapid growth during the first year of life also have long-term consequences. Knowledge of the changes in body composition in early life can help to better define nutritional needs at these ages. Several methods are available for measuring body composition of neonates and infants. Most focus on an assessment of either body fatness or bone mineralization; only a few can monitor the quality of the non-fat lean tissues. This paper provides an evaluation of the different approaches currently available to monitor infant body composition, identifying both their strengths and limitations.

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Eur J Appl Physiol. 2003 Sep;90(1-2):178-84. Epub 2003 Jul 9.

Jürimäe T, Sudi K, Payerl D, Leppik A, Jürimäe J, Müller R, Tafeit E.

Faculty of Exercise and Sport Sciences, University of Tartu, 18. Ulikooli Street, 50090 Tartu, Estonia. toivoj@ut.ee

The aim of this study was to compare the relationships between bioelectrical impedance and thicknesses of adipose tissue measured by traditional skinfold caliper (double thickness) or a LIPOMETER device (single non-compressed thickness) in 9- to 12-year-old boys ( n=52) and girls ( n=44). In total, nine skinfolds (triceps, subscapular, biceps, iliac crest, supraspinale, abdominal, front thigh, medial calf, mid-axilla) were measured. Measurement for the thickness of subcutaneous adipose tissue layers (SAT-layers) by LIPOMETER were performed at 15 body sites (neck, triceps, biceps, upper back, front chest, lateral chest, upper abdomen, lower abdomen, lower back, hip, front thigh, lateral thigh, rear thigh, inner thigh, calf). Body bioelectrical impedance was measured with a multiple-frequency impedance device Multiscan-5000 (Bodystat, UK). Impedance at 50 kHz highly correlated with body mass ( r=-0.47 in boys, r=-0.46 in girls, r=-0.47 in total group). The relationship with body height was significant only in girls ( r=-0.42). Skinfold thicknesses measured by caliper did not correlate significantly with body impedance at 50 kHz. SAT-layers measured by LIPOMETER at triceps, front thigh, lateral thigh and rear thigh sites in boys and at the lateral thigh site in girls correlated significantly with body impedance measured at 50 kHz. Stepwise multiple regression analysis indicated that the iliac crest and front thigh skinfold thicknesses measured by caliper characterized only 5.7-12.0% of the impedance at 50 kHz in the total group ( n=96). From the measured 15 SAT-layers, the most significant was the lateral thigh layer which characterized 20.0%, 11.9% and 13.6% of the impedance at 50 kHz in boys, girls and the total group, respectively. It was concluded that the influence of subcutaneous adipose tissue on body impedance is relatively low in children. However, SAT-layers have a slightly higher influence on body impedance than skinfold thicknesses measured by caliper. The sum of skinfolds or SAT-layers did not correlate significantly with body impedance in any group.

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Obes Res. 2004 Oct;12(10):1633-40.

Eisenmann JC, Heelan KA, Welk GJ.

255 Forker, Department of Health and Human Performance, Iowa State University, Ames, IA 50011, USA. jce@iastate

OBJECTIVE: To examine the inter-relationships of body composition variables derived from simple anthropometry [BMI and skinfolds (SFs)], bioelectrical impedance analysis (BIA), and dual energy x-ray (DXA) in young children. RESEARCH METHODS AND PROCEDURES: Seventy-five children (41 girls, 34 boys) 3 to 8 years of age were assessed for body composition by the following methods: BMI, SF thickness, BIA, and DXA. DXA served as the criterion measure. Predicted percentage body fat (%BF), fat-free mass (FFM; kilograms), and fat mass (FM; kilograms) were derived from SF equations [Slaughter (SL)1 and SL2, Deurenberg (D) and Dezenberg] and BIA. Indices of truncal fatness were also determined from anthropometry. RESULTS: Repeated measures ANOVA showed significant differences among the methods for %BF, FFM, and FM. All methods, except the D equation (p = 0.08), significantly underestimated measured %BF (p < 0.05). In general, correlations between the BMI and estimated %BF were moderate (r = 0.61 to 0.75). Estimated %BF from the SL2 also showed a high correlation with DXA %BF (r = 0.82). In contrast, estimated %BF derived from SFs showed a low correlation with estimated %BF derived from BIA (r = 0.38); likewise, the correlation between DXA %BF and BIA %BF was low (r = 0.30). Correlations among indicators of truncal fatness ranged from 0.43 to 0.98. DISCUSSION: The results suggest that BIA has limited utility in estimating body composition, whereas BMI and SFs seem to be more useful in estimating body composition during the adiposity rebound. However, all methods significantly underestimated body fatness as determined by DXA, and, overall, the various methods and prediction equations are not interchangeable.

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Am J Clin Nutr. 2002 Nov;76(5):991-9.

Horlick M, Arpadi SM, Bethel J, Wang J, Moye J Jr, Cuff P, Pierson RN Jr, Kotler D.

Children’s Hospital of New York, USA. mnh1@columbia.edu

BACKGROUND: Bioelectrical impedance analysis (BIA) is an attractive method of measuring pediatric body composition in the field, but the applicability of existing equations to diverse populations has been questioned. OBJECTIVE: The objectives were to evaluate the performance of 13 published pediatric BIA-based predictive equations for total body water (TBW) and fat-free mass (FFM) and to refit the best-performing models. DESIGN: We used TBW by deuterium dilution, FFM by dual-energy X-ray absorptiometry, and BIA-derived variables to evaluate BIA models in a cross-sectional study of 1291 pediatric subjects aged 4-18 y, from several ethnic backgrounds, including 54 children with HIV infection and 627 females. The best-performing models were refitted according to criterion values from this population, cross-validated, and assessed for performance. Additional variables were added to improve the predictive accuracy of the equations. RESULTS: The correlation between predicted and criterion values was high for all models tested, but bias and precision improved with the refitted models. The 95% limits of agreement between predicted and criterion values were 16% and 11% for TBW and FFM, respectively. Bias was significant for some subgroups, and there was greater loss of precision in specific age groups and pubertal stages. The models with additional variables eliminated bias, but the limits of agreement and the loss of precision persisted. CONCLUSION: This study confirms that BIA prediction models may not be appropriate for individual evaluation but are suitable for population studies. Additional variables may be necessary to eliminate bias for specific subgroups.

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Int J Obes Relat Metab Disord. 2000 Aug;24(8):982-8.

Lohman TG, Caballero B, Himes JH, Davis CE, Stewart D, Houtkooper L, Going SB, Hunsberger S, Weber JL, Reid R, Stephenson L.

University of Arizona, Tucson, AZ, USA.

OBJECTIVE: Obesity, as measured by body mass index, is highly prevalent in Native American children, yet there are no valid equations to estimate total body fatness for this population. This study was designed to develop equations to estimate percentage body fat from anthropometry and bioelectrical impedance as a critical part of Pathways, a multi-site study of primary prevention of obesity in Native American children. DESIGN: Percentage fat was estimated from deuterium oxide dilution in 98 Native American children (Pima/Maricopa, Tohono O’odham and White Mountain Apache tribes) between 8 and 11 y of age. The mean fat content (38.4%+/-8. 1%) was calculated assuming the water content of the fat-free body was 76%. Initial independent variables were height, weight, waist circumference, six skinfolds and whole-body resistance and reactance from bioelectrical impedance (BIA). RESULTS: Using all-possible-subsets regressions with the Mallows C (p) criterion, and with age and sex included in each regression model, waist circumference, calf and biceps skinfolds contributed least to the multiple regression analysis. The combination of weight, two skinfolds (any two out of the four best: triceps, suprailiac, subscapular and abdomen) and bioelectrical impedance variables provided excellent predictability. Equations without BIA variables yielded r2 almost as high as those with BIA variables. The recommended equation predicts percentage fat with a root mean square error=3.2% fat and an adjusted r2=0.840. CONCLUSION: The combination of anthropometry and BIA variables can be used to estimate total body fat in field studies of Native American children. The derived equation yields considerably higher percentage fat values than other skinfold equations in children.

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Eur J Clin Nutr. 1997 Oct;51(10):673-7.

Bandini LG, Vu DM, Must A, Dietz WH.

Clinical Research Center, Massachusetts Institute of Technology, Cambridge 02139, USA.

OBJECTIVES: To determine in non-obese pre-menarcheal girls if bioelectrical impedance (BIA) is a better predictor of body fatness than triceps skinfold (TSF) or body mass index (BMI) and to cross-validate published equations for determination of fat-free mass (FFM) from BIA in pre-menarcheal girls. DESIGN: Cross-sectional analysis of data from 132 non-obese pre-menarcheal girls. The relationship of percent body fat (%BF), derived from isotopic dilution of H2 18O to TSF, BMI, and %BF by BIA, calculated from measures of height, weight and resistance was examined by correlation analysis. SETTING: Massachusetts Institute of Technology (MIT) Clinical Research Center in Cambridge, MA, USA. SUBJECTS: Pre-menarcheal girls aged 8-12 y were recruited from local schools, MIT summer day camp and by word of mouth. RESULTS: TSF accounted for 68% of the explained variance (R2) in the prediction of %BF measured by H2 18O, compared to 38% for BMI and 70% for BIA. Prediction of FFM by comparison of published equations was evaluated in this population. The predictive ability differed by Tanner stage. Kushner’s equation (Kushner et al, 1992), based solely on height2/resistance was the only equation that provided estimates that did not differ significantly from measured values among all Tanner stages. CONCLUSIONS: BIA appears to be a valid and reliable measure of FFM but is no better than TSF in predictions of body fat.

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Growth Dev Aging. 1988 Spring;52(1):37-40.

Cordain L, Whicker RE, Johnson JE.

Department of Exercise and Sport Science, Colorado State University, Fort Collins 80523.

Estimation of body composition by measurement of tetrapolar bioelectrical resistive impedance (R) is a technique only recently validated in adults. To evaluate this technique in children, 16 girls aged 11.6 +/- 0.9 yr (mean +/- SD) and 14 boys aged 12.5 +/- 1.0 yr were assessed for fat free mass (FFM) by hydrostatic weighing, total body potassium (TBK) by whole body counting of 40K, and R by an electrical impedance plethysmograph. Significant relationships (P less than 0.001) were demonstrated between TBK and ht2/R (r = 0.92), and FFM and ht2/R (r = 0.83). The reliability coefficient for the impedance measurements was r = 0.97. The following equation describes FFM in the present group of children: FFM (kg) = 6.86 + 0.81 x (ht2/R), r = 0.83, P less than 0.001, SEE = 4.08. These data suggest that impedance measurements are valid and reliable predictors of FFM in pediatric populations.

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Pediatrics. 1998 Sep;102(3):E29.

The Maternal and Child Health Bureau, Health Resources and Services Administration and the Department of Health and Human Services.Barlow SE, Dietz WH.

Division of Pediatric Gastroenterology and Nutrition, New England Medical Center, Boston, Massachusetts, USA.

OBJECTIVES: The development of recommendations for physicians, nurse practitioners, and nutritionists to guide the evaluation and treatment of overweight children and adolescents. METHODS: The Maternal and Child Health Bureau, Health Resources and Services Administration, the Department of Health and Human Services convened a committee of pediatric obesity experts to develop the recommendations. RESULTS: The Committee recommended that children with a body mass index (BMI) greater than or equal to the 85th percentile with complications of obesity or with a BMI greater than or equal to the 95th percentile, with or without complications, undergo evaluation and possible treatment. Clinicians should be aware of signs of the rare exogenous causes of obesity, including genetic syndromes, endocrinologic diseases, and psychologic disorders. They should screen for complications of obesity, including hypertension, dyslipidemias, orthopedic disorders, sleep disorders, gall bladder disease, and insulin resistance. Conditions that indicate consultation with a pediatric obesity specialist include pseudotumor cerebri, obesity-related sleep disorders, orthopedic problems, massive obesity, and obesity in children younger than 2 years of age. Recommendations for treatment evaluation included an assessment of patient and family readiness to engage in a weight-management program and a focused assessment of diet and physical activity habits. The primary goal of obesity therapy should be healthy eating and activity. The use of weight maintenance versus weight loss to achieve weight goals depends on each patient’s age, baseline BMI percentile, and presence of medical complications. The Committee recommended treatment that begins early, involves the family, and institutes permanent changes in a stepwise manner. Parenting skills are the foundation for successful intervention that puts in place gradual, targeted increases in activity and targeted reductions in high-fat, high-calorie foods. Ongoing support for families after the initial weight-management program will help families maintain their new behaviors. CONCLUSIONS: These recommendations provide practical guidance to pediatric clinicians who evaluate and treat overweight children.

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Clin Nutr. 2007 Dec;26(6):771-7. Epub 2007 Oct 23.

Thomson R, Brinkworth GD, Buckley JD, Noakes M, Clifton PM.

CSIRO Human Nutrition, PO Box 10041 BC, Adelaide 5000, Australia.

AIMS: To compare estimations of body composition using two different methods of bioelectrical impedance analysis (BIA) with dual X-ray absorptiometry (DXA) for estimating body composition during weight loss in overweight and obese young females. METHODS: Twenty-four overweight or obese females (age 29.5+/-6.1 years, BMI 36.4+/-4.3 kg/m(2)) had body composition assessed using single-frequency (Tanita Ultimate Scale; SF-BIA) and multi-frequency (Impedimed SFB7; MF-BIA) BIA and DXA before and after a 10-week weight loss intervention. RESULTS: MF-BIA estimates of body composition showed good absolute agreement with DXA, as evidenced by the small biases in the estimation of fat free mass (FFM), fat mass (FM) and percentage body fat (BF%); however, the limits of agreement for each variable were wide (bias +/-1.96 standard deviation; FFM -1.6+/-6.5 kg, FM 1.6+/-6.5 kg, BF% 1.4+/-6.3%). SF-BIA exhibited a larger bias with wide limits of agreement (FFM 3.8+/-9.1 kg, FM -3.8+/-9.1 kg, BF% -4.37+/-10.3%). During weight loss the values provided by MF-BIA and SF-BIA were not significantly different from DXA (p> or =0.89) due to small bias and the limits of agreement were narrow (MF-BIA: FFM -0.01+/-3.74 kg, FM 0.01+/-3.74 kg, BF% 0.22+/-3.40%; SF-BIA: FFM 0.40+/-3.92 kg, FM -0.40+/-3.92 kg, BF% 0.25+/-3.40%). CONCLUSION: Compared with DXA, both the MF-BIA and SF-BIA accurately assessed changes in body composition with weight loss but, compared with SF-BIA, MF-BIA provided superior cross-sectional estimates of body composition.

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Nutrition. 2003 Jun;19(6):558-9.

Comment on:

Nutrition. 2003 Jun;19(6):492-6.

Gartner A.

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Nutrition. 2002 May;18(5):383-7.

Piccoli A, Fanos V, Peruzzi L, Schena S, Pizzini C, Borgione S, Bertino E, Chiaffoni G, Coppo R, Tatò L.

Department of Medical and Surgical Sciences, University of Padova, Padova, Italy. apiccoli@unipd.it

OBJECTIVE: To determine the reference, bivariate, tolerance intervals of the whole-body impedance vector for healthy white neonates, we performed an observational, cross-sectional study in two university hospitals. METHODS: The impedance vector (standard, tetrapolar analysis at 50-kHz frequency) was measured in 163 consecutive subjects (87 boys and 76 girls) with postnatal ages of 1 to 7 d. Bivariate vector analysis was conducted with the resistance-reactance (RXc) graph method. RESULTS: The age-specific 95% confidence intervals of mean vectors and the 95%, 75%, and 50% tolerance intervals for individual vector measurements were plotted using R and Xc components standardized by the subject’s crown-to-heel length (height). Mean vectors from the groups (1, 2, and 3 to 7 d) with overlapping 95% confidence ellipses were considered representative of only one age class of 1 to 7 d. The impedance vector distribution of neonates also was compared with healthy white children (1014 boys and 1030 girls, age 2-15 y) and adult subjects (354 men and 372 women, age 15-85 y) from the same geographic area. There was a definite, progressive, vector shortening from birth, through ages 2 to 15 y, toward the adults’ vector position. CONCLUSIONS: We established the reference, bivariate, 95%, 75%, and 50% tolerance intervals of the impedance vector in the first postnatal week for healthy white neonates, with which the vectors from infants with altered body composition can be tested (free software is available from apiccoli@ unipd.it).

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J Am Diet Assoc. 2008 Jan;108(1):136-9.

Cleary J, Daniells S, Okely AD, Batterham M, Nicholls J.

Department of Clinical Nutrition, Wollongong Hospital, Wollongong, NSW, Australia.

Bioelectrical impedance equations are frequently used by food and nutrition professionals to estimate percent fat mass in overweight and obese children. However, it is not known whether they are accurate for such children, as they have been primarily developed for children of varying body weights. The aim of this cross-sectional study was to evaluate the predictive validity of four previously published prediction equations developed for the pediatric population, among a sample of overweight and obese children. Thirty overweight or obese children (mean age=7.57+/-1.28 years) underwent measurement of fat mass, percent fat mass, and fat-free mass using dual-energy x-ray absorptiometry (DEXA) and bioelectrical impedance analysis (BIA). Impedance values from the BIA were entered into the four prediction equations and Pearson correlations used to determine the significance of associations between each of the BIA prediction equations and DEXA for percent fat mass, fat mass, and fat-free mass. For percent fat mass, paired t tests were used to assess differences between the methods and the technique of Bland and Altman was used to determine bias and error. Results showed that the mean percent fat mass as determined by DEXA for this age group was 40.79%. In comparison with other BIA prediction equations, the Schaefer equation had the closest mean value of 41.98%, and was the only equation not to significantly differ from the DEXA (P=0.121). This study suggests that the Schaefer equation is the only accurate BIA prediction equation for assessing percent fat mass in this sample of overweight and obese children from primarily white backgrounds.

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Bull World Health Organ. 2001;79(6):541-5.

Rätsch IM, Catassi C.

Department of Paediatrics, University of Ancona, Via F. Corridoni 11, 60123 Ancona, Italy.

OBJECTIVE: To characterize the clinical and nutritional impact of coeliac disease (gluten-sensitive enteropathy) among Saharawi children living as refugees in Algeria. METHODS: A total of 65 Saharawi children with coeliac disease were compared with 71 age-matched non-coeliac controls. For each participant, the clinical history was taken and a clinical examination, non-quantitative 24-hour dietary recall, anthropometric and skinfold measurements, bioelectric impedance analysis (BIA) of body composition, and venous blood sampling for haemoglobin determination were performed. RESULTS: Gluten-containing food, especially bread, was the staple diet of Saharawi children. Abdominal pain and distension were significantly commoner among children with coeliac disease than in controls (P < 0.05). The mean height-for-age was significantly lower in such children than in controls (-2.5 +/- 1.4 units vs -1.8 +/- 1.3 units, respectively, P < 0.01). No significant differences were found for either skinfold or BIA measurements. Haemoglobin values tended to be lower in children with coeliac disease than in controls. CONCLUSIONS: Coeliac disease has a negative effect on the health status of Saharawi refugee children. Because of the high prevalence of the condition in the Saharawi, a specific programme for treating all affected individuals should be established. Further studies are required to quantify the impact of coeliac disease in other areas of the developing world.

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Am J Clin Nutr. 2005 Apr;81(4):757-61.

de Simone G, Devereux RB, Kizer JR, Chinali M, Bella JN, Oberman A, Kitzman DW, Hopkins PN, Rao DC, Arnett DK.

Department of Medicine, The New York Presbyterian Hospital, Weill Medical College of Cornell University, New York, NY, USA. simogi@unina.it

BACKGROUND: We have shown that increased cardiac output is related to both fat-free mass and fat mass in obesity. OBJECTIVE: We studied the association of body fat distribution and body composition with flow-resistance relations in overweight. DESIGN: We studied 521 overweight, nonobese participants in the Hypertension Genetic Epidemiology Network (HyperGEN) Study-a component of the National Heart, Lung, and Blood Institute Family Blood Pressure Program, designed to assess the genetic basis of hypertension. Participants had normal ventricular function and no cardiovascular disease: 261 with central fat distribution (CFD) (waist girth >88 cm in women and >102 cm in men) and 260 with peripheral fat distribution (PFD). Fat-free mass (FFM) and fat mass (FM) were measured by bioelectric impedance. Body composition was estimated as FM/FFM. Echocardiographic stroke volume (SV) and cardiac output (CO) were measured. RESULTS: Hypertension was present in 73% of the subjects with PFD and in 78% with CFD. Overweight with CFD was associated with greater FM/FFM in both normotensive and hypertensive participants. After FFM, age, sex, and race were controlled for, SV and CO were higher in subjects overweight with CFD than in those with PFD, whereas peripheral resistance was not significantly different. Differences in CO between CFD and PFD were reduced after further adjustment for FM. After the covariates were controlled for, hypertensive subjects had higher peripheral resistance and lower arterial compliance than did normotensive participants, but cardiac output was not significantly different. CONCLUSION: CFD is associated with more severe abnormalities in body composition and with higher CO independently of FFM in overweight, nonobese subjects.

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