Comparison of bioelectrical impedance analysis and dual energy X-ray absorptiometry for assessment of body composition in children

Eating contexts at breakfast, lunch, and dinner: Associations with ultra-processed foods consumption and overweight in Brazilian adolescents (EVA-JF Study)

This cross-sectional study estimated associations of eating contexts (including regularity of meals, places where they occur, and if they take place with attention and in company) with food consumption by degree of industrial processing and overweight indicators in a sample of Brazilian adolescents (14-19 years old) enrolled in 29 public schools in Juiz de Fora, MG (n = 805). We used an exploratory questionnaire, which was submitted to cluster analysis. Three clusters were identified: cluster 1 (n = 572), "appropriate eating contexts at breakfast, lunch, and dinner"; cluster 2 (n = 139), "inappropriate eating context at breakfast"; and cluster 3 (n = 94) "inappropriate eating context at dinner". The evaluation of food consumption involved two 24-h dietary recalls, whose items were analyzed according to the NOVA classification system. Linear regression models were performed, using cluster 1 as reference. Clusters 2 and 3 were associated with an increase in the energy fraction from ultra-processed foods [respectively, β = 2.55% (IC 95%: 0.50; 5.05) and β = 4.18% (IC 95%: 1.21; 7.14)]; and cluster 2 was associated with a reduction in the energy fraction from unprocessed or minimally processed foods and processed culinary ingredients [β = -3.61% (IC 95%: -6.40; -0.82)]. Additionally, clusters 2 and 3 were associated with an increase of body mass index for age [respectively, β = 0.23 z-score (IC 95%: 0.01; 0.46) and β = 0.27 z-score (IC 95%: 0.02; 0.54)]; and cluster 2 was associated with an increase of body fat [β = 1.21% (IC 95%: 0.23; 2.64)]. In conclusion, inappropriate eating contexts at breakfast and dinner were associated with higher ultra-processed food intake, higher body mass index and higher body fat percentage.

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.

Validity of quantitative ultrasound and bioelectrical impedance analysis for measuring bone density and body composition in children

BACKGROUND/OBJECTIVES

Using dual X-ray absorptiometry (DXA) to assess body composition in children has limitations including expense, lack of portability, and exposure to radiation. The aims of this study were to examine: (1) validity of quantitative ultrasound (QUS) against DXA for measuring bone density and (2) the validity of in-built algorithm of bioelectrical impedance analysis (BIA) for measuring body composition in children (8-13 years) living in New Zealand.

SUBJECTS/METHODS

Total body less head (TBLH), bone mineral content (BMC), bone mineral density (BMD), and body composition were measured with DXA (QDR Discovery A, Hologic, USA); calcaneal BMD and stiffness index (SI) with QUS (Sahara QUS, Hologic, USA), and BIA on the InBody 230 (Biospace Ltd., Seoul, Korea). Relative validity was assessed using Pearson's and Lin's concordance correlation coefficients (CCC), and Bland-Altman plots.

RESULTS

In 124 healthy children, positive correlations between QUS SI and DXA (BMC and BMD) were observed (range = 0.30-0.45, P < 0.01). Results from Lin's CCC test showed almost perfect correlations between BIA and DXA fat free mass (0.96), fat mass (0.92), and substantial correlation for percentage of fat mass (0.75) (P < 0.05).

CONCLUSION

Although BIA results were not as accurate as DXA and DXA remains the gold standard method for clinical assessment, BIA can be an alternative method for investigating body composition among children in large cohort field studies. Calcaneal QUS and DXA are not interchangeable methods for measuring bone density in children similar to our study population.

Prevalence and association of single nucleotide polymorphisms with sarcopenia in older women depends on definition

The prevalence of sarcopenia depends on the definition used. There are, however, consistent sarcopenic characteristics, including a low muscle mass and muscle strength. Few studies have investigated the relationship between sarcopenia and genotype. A cross-sectional study was conducted with 307 community-dwelling ≥60-year-old women in South Cheshire, UK. Handgrip strength was assessed with a handgrip dynamometer and skeletal muscle mass was estimated using bioelectrical impedance. DNA was extracted from saliva (∼38%) or blood (∼62%) and 24 single-nucleotide polymorphisms (SNPs) were genotyped. Three established sarcopenia definitions - %Skeletal Muscle Mass (%SMM), Skeletal Muscle Mass Index (SMI) and European Working Group on Sarcopenia in Older People (EWGSOP) - were used to assess sarcopenia prevalence. Binary logistic regression with age as covariate was used to identify SNPs associated with sarcopenia. The prevalence of sarcopenia was: %SMM 14.7%, SMI 60.6% and EWGSOP 1.3%. Four SNPs were associated with the %SMM and SMI definitions of sarcopenia; FTO rs9939609, ESR1 rs4870044, NOS3 rs1799983 and TRHR rs7832552. The first three were associated with the %SMM definition, and TRHR rs7832552 with the SMI definition, but none were common to both sarcopenia definitions. The gene variants associated with sarcopenia may help proper counselling and interventions to prevent individuals from developing sarcopenia.

Impaired Glucose Tolerance in Adults with Duchenne and Becker Muscular Dystrophy

The aim of this study was to determine the response to an oral glucose tolerance test (OGTT) in adult males with Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD), and to investigate whether body composition contributes to any variance in the glucose response. Twenty-eight adult males with dystrophinopathy (BMD, n = 13; DMD, n = 15) and 12 non-dystrophic controls, ingested 75 g oral anhydrous glucose solution. Fingertip capillary samples were assessed for glucose at 30-min intervals over 2-h post glucose ingestion. Fat free mass relative to body mass (FFM/BM) and body fat (BF%) was assessed using bioelectrical impedance. Vastus lateralis muscle anatomical cross sectional area (VL ACSA) was measured using B-mode ultrasonography. Blood glucose was higher in MD groups than control at 60, 90 and 120 min post ingestion of glucose. Compared to controls, FFM/BM and VL ACSA were lower in MD groups compared to controls (p < 0.001). Glucose tolerance values at 120 min were correlated with FFM/BM and BF% in the BMD group only. Our results suggest that glucose tolerance is impaired following OGTT in adult males with BMD and DMD. It is recommended that adults with BMD and DMD undertake routine glucose tolerance assessments to allow early detection of impaired glucose tolerance.

Relationships between muscle size, strength, and physical activity in adults with muscular dystrophy

BACKGROUND

Muscular dystrophy (MD) is characterized by progressive muscle wasting and weakness, yet few comparisons to non-MD controls (CTRL) of muscle strength and size in this adult population exist. Physical activity (PA) is promoted to maintain health and muscle strength within MD; however, PA reporting in adults with MD is limited to recall data, and its impact on muscle strength is seldom explored.

METHODS

This study included 76 participants: 16 non-MD (CTRL, mean age 35.4), 15 Duchenne MD (DMD, mean age 24.2), 18 Becker's MD (BMD, mean age 42.4), 13 limb-girdle MD (LGMD, mean age 43.1), and 14 facioscapulohumeral MD (mean age 47.7). Body fat (%) and lean body mass (LBM) were measured using bioelectrical-impedance. Gastrocnemius medialis (GM) anatomical cross-sectional area (ACSA) was determined using B-mode ultrasound. Isometric maximal voluntary contraction (MVC) was assessed during plantar flexion (PFMVC) and knee extension (KEMVC). PA was measured for seven continuous days using triaxial accelerometry and was expressed as daily average minutes being physically active (TPAmins ) or average daily percentage of waking hours being sedentary (sedentary behaviour). Additionally, 10 m walk time was assessed.

RESULTS

Muscular dystrophy groups had 34-46% higher body fat (%) than CTRL. DMD showed differences in LBM with 21-28% less LBM than all other groups. PFMVC and KEMVC were 36-75% and 24-92% lower, respectively, in MD groups than CTRL. GM ACSA was 47% and 39% larger in BMD and LGMD, respectively, compared with CTRL. PFMVC was associated with GM ACSA in DMD (P = 0.026, R = 0.429) and CTRL (P = 0.015, R = 0.553). MD groups were 14-38% more sedentary than CTRL groups, while DMD were more sedentary than BMD (14%), LGMD (8%), and facioscapulohumeral MD (14%). Sedentary behaviour was associated with LBM in DMD participants (P = 0.021, R = -0.446). TPAmins was associated with KEMVC (P = 0.020, R = 0.540) in BMD participants, while TPAmins was also the best predictor of 10 m walk time (P < 0.001, R2  = 0.540) in ambulant MD, revealed by multiple linear regression.

CONCLUSIONS

Quantified muscle weakness and impaired 10 m walking time is reported in adults with MD. Muscle weakness and 10 m walk time were associated with lower levels of TPA in adults with MD. Higher levels of sedentary behaviour were associated with reduced LBM in DMD. These findings suggest a need for investigations into patterns of PA behaviour, and relevant interventions to reduce sedentary behaviour and encourage PA in adults with MD regardless of impairment severity.

The cardiorespiratory response and physiological determinants of the assisted 6-minute handbike cycle test in adult males with muscular dystrophy

INTRODUCTION

The assisted 6-minute cycle test (A6MCT) distance was assessed in adults with muscular dystrophy (MD).

METHODS

Forty-eight males, including those with Duchenne MD (DMD), limb-girdle MD (LGMD), fascioscapulohumeral MD (FSHD), and Becker MD (BMD), as well as a group without MD (CTRL), completed handgrip strength (HGS), lung function [forced expiratory volume in 1 second (FEV1 ) and forced vital capacity (FVC)], body fat, and biceps thickness assessments. During the A6MCT, ventilation (VE), oxygen uptake (VO2 ), carbon dioxide (VCO2 ), and heart rate (HR) were recorded.

RESULTS

A6MCT and HGS were lower in MD than CTRL subjects. FEV1 , FVC, and biceps thickness were lower in MD than CTRL; lower in DMD than BMD, LGMD, and FSHD; but were not different between BMD, LGMD, and FSHD. A6MCT correlated with HGS, FEV1 , FVC, body fat, VO2 , VCO2 , HR, and VE (r = 0.455-0.708) in pooled BMD, LGMD, and FSHD participants.

DISCUSSION

A shorter A6MCT distance in adult males with MD was attributable to HGS and lung function. The A6MCT is appropriate for assessment of physical function in adults with MD. Muscle Nerve 58: 427-433, 2018.

Microvascular endothelial function in Japanese early adolescents

Endothelial dysfunction is the early predictive factor for the development of atherosclerosis and future cardiovascular diseases in adulthood. The prevalence of endothelial dysfunction in children and early adolescents is increasing worldwide. Peripheral arterial tonometry is a noninvasive technique for assessing peripheral microvascular function and is used as a validated marker of endothelial function. We assessed anthropometric parameters, blood pressure, arterial stiffness, and peripheral endothelial function in 157 Japanese early adolescents (75 boys and 82 girls). We measured peripheral endothelial function by using peripheral arterial tonometry to determine the reactive hyperemia index, and assessed the association of reactive hyperemia index with parameters of anthropometry and arterial stiffness. The mean reactive hyperemia index of all subjects was 1.85 ± 0.6, and there was no difference of reactive hyperemia index according to sex. Reactive hyperemia index was significantly associated with systolic and diastolic blood pressures, and had no correlation with anthropometric parameters and arterial stiffness markers. The reactive hyperemia index values among Japanese early adolescents were similar to those reported in previous studies on children and early adolescents. This noninvasive technique may be useful for the assessment of microvascular endothelial function among children and early adolescents.

Resting Energy Expenditure in Adults with Becker's Muscular Dystrophy

Purpose

The purpose of this study was: 1) To compare Resting energy expenditure (REE) in adult males with Becker’s Muscular Dystrophy (BeMD, n = 21, 39 ±12 years) and healthy controls (CTRL, n = 12, 37 ±12 years) 2) Determine whether other physiological parameters correlate with REE in BeMD, and 3) Compare current prediction methods of REE with measured REE.

Methods

REE was calculated via indirect calorimetry using continuous, expired gas analysis following an overnight fast. Fat free mass (FFM) and fat mass were measured by bioelectrical impedance. B-mode ultrasound measured Tibialis Anterior (TA) and Gastrocnemius Medialis (GM) anatomical cross sectional area (ACSA). The Bone Specific Physical Activity Questionnaire measured physical activity.

Results

No difference in REE was found between CTRL and BeMD groups (1913 ±203 & 1786 ±324 Kcal respectively). Other physiological comparisons showed increased fat mass (+54%), decreased TA ACSA (-42%), increased GM ACSA (+25%) as well as reduced respiratory function (FVC -28%; FEV1−27%) in BeMD adults compared to controls. REE estimated from prediction equations (Schofield’s) in Muscular Dystrophy were different from measured REE (P<0.05, bias = -728kcal), while the Mifflin equation was no different from measured REE (r² = 0.58, Bias = -8kcal). Within the present BeMD, REE predicted from FFM (REE = FFM x 34.57–270; r² = 0.85) and body mass (REE = BM x 15.65 + 421.5; r² = 0.66), were not different from measured REE (bias equals 0 and 0.2kcals, respectively)

Conclusions

Despite no differences in REE between CTRL and BeMD adults, increased fat masses highlights the requirement for explicit nutritional guidelines, as well as maintenance of physical activity levels, where possible. Prediction equations are frequently used in clinical settings, however these have been shown to be less accurate in BeMD; therefore, the equations proposed here should be used where possible.

Fat-free mass prediction equations for bioelectric impedance analysis compared to dual energy X-ray absorptiometry in obese adolescents: a validation study

Background

In clinical practice, patient friendly methods to assess body composition in obese adolescents are needed. Therefore, the bioelectrical impedance analysis (BIA) related fat-free mass (FFM) prediction equations (FFM-BIA) were evaluated in obese adolescents (age 11–18 years) compared to FFM measured by dual-energy x-ray absorptiometry (FFM-DXA) and a new population specific FFM-BIA equation is developed.

Methods

After an overnight fast, the subjects attended the outpatient clinic. After measuring height and weight, a full body scan by dual-energy x-ray absorptiometry (DXA) and a BIA measurement was performed. Thirteen predictive FFM-BIA equations based on weight, height, age, resistance, reactance and/or impedance were systematically selected and compared to FFM-DXA. Accuracy of FFM-BIA equations was evaluated by the percentage adolescents predicted within 5 % of FFM-DXA measured, the mean percentage difference between predicted and measured values (bias) and the Root Mean Squared prediction Error (RMSE). Multiple linear regression was conducted to develop a new BIA equation.

Results

Validation was based on 103 adolescents (60 % girls), age 14.5 (sd1.7) years, weight 94.1 (sd15.6) kg and FFM-DXA of 56.1 (sd9.8) kg. The percentage accurate estimations varied between equations from 0 to 68 %; bias ranged from −29.3 to +36.3 % and RMSE ranged from 2.8 to 12.4 kg. An alternative prediction equation was developed: FFM = 0.527 * H(cm)²/Imp + 0.306 * weight - 1.862 (R² = 0.92, SEE = 2.85 kg). Percentage accurate prediction was 76 %.

Conclusions

Compared to DXA, the Gray equation underestimated the FFM with 0.4 kg (55.7 ± 8.3), had an RMSE of 3.2 kg, 63 % accurate prediction and the smallest bias of (−0.1 %). When split by sex, the Gray equation had the narrowest range in accurate predictions, bias, and RMSE. For the assessment of FFM with BIA, the Gray-FFM equation appears to be the most accurate, but 63 % is still not at an acceptable accuracy level for obese adolescents. The new equation appears to be appropriate but await further validation. DXA measurement remains the method of choice for FFM in obese adolescents.

Trial registration

Netherlands Trial Register (ISRCTN27626398).

Association of thyroid hormones with obesity and metabolic syndrome in Japanese children

Obesity is associated with health consequences, and thyroid dysfunction may be an adaption to the increased energy expenditure in obesity. With the rising prevalence of obesity in childhood, the prevalence of metabolic syndrome may also increase. In the current study, we have shown gender differences in the association of thyroid hormones with obesity, and attempted to elucidate the relationship between thyroid hormones and anthropometric parameters and biochemical data in obese Japanese children. We analyzed anthropometric measurements, blood pressure, body composition, thyroid hormones, and lipid profiles in 283 obese children. The association between thyroid hormones and several parameters differed by gender. The free T3 to free T4 ratio (fT3/fT4) in boys was negatively associated with the quantitative insulin sensitivity check index, whereas in girls, thyroid-stimulating hormone levels were positively correlated with levels of glucose, diastolic blood pressure, and non-high density lipoprotein-cholesterol, and fT3/fT4 was positively correlated with uric acid levels. FT3/fT4 in boys with metabolic syndrome was relatively higher than in those without metabolic syndrome. The cause of gender differences is unknown. Therefore, further studies with larger sample sizes and a long-term follow-up period are needed to address the influence of thyroid hormones on various parameters.

Systematic review to identify and appraise outcome measures used to evaluate childhood obesity treatment interventions (CoOR): evidence of purpose, application, validity, reliability and sensitivity

BACKGROUND

Lack of uniformity in outcome measures used in evaluations of childhood obesity treatment interventions can impede the ability to assess effectiveness and limits comparisons across trials.

OBJECTIVE

To identify and appraise outcome measures to produce a framework of recommended measures for use in evaluations of childhood obesity treatment interventions.

DATA SOURCES

Eleven electronic databases were searched between August and December 2011, including MEDLINE; MEDLINE In-Process and Other Non-Indexed Citations; EMBASE; PsycINFO; Health Management Information Consortium (HMIC); Allied and Complementary Medicine Database (AMED); Global Health, Maternity and Infant Care (all Ovid); Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCOhost); Science Citation Index (SCI) [Web of Science (WoS)]; and The Cochrane Library (Wiley) - from the date of inception, with no language restrictions. This was supported by review of relevant grey literature and trial databases.

REVIEW METHODS

Two searches were conducted to identify (1) outcome measures and corresponding citations used in published childhood obesity treatment evaluations and (2) manuscripts describing the development and/or evaluation of the outcome measures used in the childhood intervention obesity evaluations. Search 1 search strategy (review of trials) was modelled on elements of a review by Luttikhuis et al. (Oude Luttikhuis H, Baur L, Jansen H, Shrewsbury VA, O'Malley C, Stolk RP, et al. Interventions for treating obesity in children. Cochrane Database Syst Rev 2009;1:CD001872). Search 2 strategy (methodology papers) was built on Terwee et al.'s search filter (Terwee CB, Jansma EP, Riphagen II, de Vet HCW. Development of a methodological PubMed search filter for finding studies on measurement properties of measurement instruments. Qual Life Res 2009;18:1115-23). Eligible papers were appraised for quality initially by the internal project team. This was followed by an external appraisal by expert collaborators in order to agree which outcome measures should be recommended for the Childhood obesity Outcomes Review (CoOR) outcome measures framework.

RESULTS

Three hundred and seventy-nine manuscripts describing 180 outcome measures met eligibility criteria. Appraisal of these resulted in the recommendation of 36 measures for the CoOR outcome measures framework. Recommended primary outcome measures were body mass index (BMI) and dual-energy X-ray absorptiometry (DXA). Experts did not advocate any self-reported measures where objective measurement was possible (e.g. physical activity). Physiological outcomes hold potential to be primary outcomes, as they are indicators of cardiovascular health, but without evidence of what constitutes a minimally importance difference they have remained as secondary outcomes (although the corresponding lack of evidence for BMI and DXA is acknowledged). No preference-based quality-of-life measures were identified that would enable economic evaluation via calculation of quality-adjusted life-years. Few measures reported evaluating responsiveness.

LIMITATIONS

Proposed recommended measures are fit for use as outcome measures within studies that evaluate childhood obesity treatment evaluations specifically. These may or may not be suitable for other study designs, and some excluded measures may be more suitable in other study designs.

CONCLUSIONS

The CoOR outcome measures framework provides clear guidance of recommended primary and secondary outcome measures. This will enhance comparability between treatment evaluations and ensure that appropriate measures are being used. Where possible, future work should focus on modification and evaluation of existing measures rather than development of tools de nova. In addition, it is recommended that a similar outcome measures framework is produced to support evaluation of adult obesity programmes.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Food prices and body fatness among youths

We examine the effect of food prices on clinical measures of obesity, including body mass index (BMI) and percentage body fat (PBF) measures derived from bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DXA), among youths ages 12 through 18 in the National Health and Nutrition Examination Survey. This is the first study to consider clinically measured levels of body composition rather than BMI to investigate the effects of food prices on obesity outcomes among youths classified by gender and race/ethnicity. Our findings suggest that increases in the real price per calorie of food for home consumption and the real price of fast-food restaurant food lead to improvements in obesity outcomes among youths. We also find that a rise in the real price of fruits and vegetables leads to increased obesity. Finally, our results indicate that measures of PBF derived from BIA and DXA are no less sensitive and in some cases more sensitive to the prices just mentioned than BMI, and serve an important role in demonstrating that rising food prices (except fruit and vegetable prices) are indeed associated with reductions in obesity rather than with reductions in body size proportions alone.

Comparison of Body Composition Methods During Weight Loss in Obese Women Using Herbal Formula

Bioelectrical impedance analysis (BIA), a device that analyzes the current conduction differences between the fat and water components is widely used for reasons that include convenience of use, non-invasiveness, safety, and low cost. Dual energy X-ray absorptiometry (DXA) allows for the assessment of total body and regional lean and fat tissues and bone mineral content (BMC). The objective of this study was to compare body composition assessments by BIA and DXA before and after a 6-week herbal diet intervention program in 50 pre-menopausal women [mean ± SD: age 30.58 ± 6.15, body mass index (BMI) 31.72 ± 3.78]. Waist-to-hip ratio (WHR) was measured by BIA and anthropometry. Lean body mass (LBM), body fat (BF), BMC and percent body fat (%BF) were measured by BIA and DXA. Highly significant correlations were observed between BIA and DXA measurements for LBM, BF, BMC and %BF (r = 0.73, 0.93, 0.53, 0.79, respectively) before the intervention. Differences between BIA and DXA measurements were observed in LBM, BF, %BF and BMC before intervention ( p < 0.01) where WHR by BIA was significantly higher compared to anthropometry before ( p < 0.01) and after the intervention ( p < 0.01). BIA underestimated LBM by 1.85 kg and overestimated BF by 2.54 kg compared to DXA before the intervention. Although BIA and DXA showed highly significant correlations for LBM, BF, BMC and %BF before the intervention, they did not produce statistically comparable results in pre-menopausal Korean women and therefore should not be used interchangeably when measuring body composition.

Pilot Study of an Active Screen Time Game Correlates with Improved Physical Fitness in Minority Elementary School Youth

OBJECTIVE

The aim of our feasibility study was to examine the acceptability and utility of "Dance Dance Revolution" (DDR) (Konami of America, Redwood City, CA)) to increase physical fitness in 8-11-year-old black and Hispanic youth.

SUBJECTS AND METHODS

Twenty-eight 4(th) and 5(th) grade children attending an afterschool program participated. Outcomes included physical activity, physical fitness, use of home DDR, survey of safety and acceptability, anthropometrics, and fasting metabolic profile measured at baseline, 12 weeks, and 30 weeks.

RESULTS

At 12 weeks, physical fitness (maximum O2 uptake [VO2max]) increased by 4.9±9.9 percent and was sustained through 30 weeks, when the VO2max was 105.0±9.9 percent (range, 93.0-133.9 percent) of baseline values. Absolute VO2max increased by 2.97±4.99 mL/kg/minute (95% confidence interval 0.75-5.19, P=0.013). Participants maintained an average of 1.12 hours/day of increased movement to music. Trends suggested increased total moderate-vigorous physical activity, decreased light activity, and a modest increase in sedentary screen time. There were no significant changes in body mass index, fasting lipids, or glucose. Participants and parents approved of the activity.

CONCLUSION

DDR appears feasible and acceptable to minority youth. DDR may increase moderate-vigorous physical activity and improve physical fitness in at-risk populations.

Ethnic variation in body composition assessment in a sample of adolescent girls

OBJECTIVE

To compare body composition assessment by bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) in a multiethnic sample of adolescent girls.

METHOD

Data were from a physical activity intervention study among 254 14-20-year-old sedentary American girls, including 69 whites, 74 blacks, 42 Hispanics, and 69 Asians. Height and weight were objectively measured. Body composition was assessed using a foot-to-foot BIA and a fan-beam DXA. We calculated ethnic-specific estimates of percentage body fat (BF%), fat mass (FM), fat mass index (FMI), fat-free mass (FFM), and fat-free mass index (FFMI) from BIA and DXA. We used Bland-Altman plots to examine ethnic-specific agreement between BIA and DXA, and used linear regression to test whether the BIA-DXA difference varied across the mean.

RESULTS

Compared to DXA, BIA estimates of fat measures (BF%, FM, and FMI) were lower and lean tissue measures (FFM and FFMI) higher. For example, the BIA-estimated BF% was lower than the DXA estimate by between 4.9% (95% CI: -5.9, -3.9) in blacks and 8.7% (-7.0, -5.0) in Asians, with large limits of agreement (-15.4 to -5.4 in blacks and -16.8 to -0.4 in Asians). Regression analysis showed that BIA-DXA differences were not constant across means for any body composition measure among Asians or for any measure except BF% among whites.

CONCLUSION

Compared to DXA, BIA yielded lower estimates of adiposity in a multiethnic adolescent sample. BIA-DXA differences varied by ethnicity, and across mean body composition values for some ethnicities.

Relationship of body mass index to percent body fat and waist circumference among schoolchildren in Japan--the influence of gender and obesity: a population-based cross-sectional study

Background

Although the correlation coefficient between body mass index (BMI) and percent body fat (%BF) or waist circumference (WC) has been reported, studies conducted among population-based schoolchildren to date have been limited in Japan, where %BF and WC are not usually measured in annual health examinations at elementary schools or junior high schools. The aim of the present study was to investigate the relationship of BMI to %BF and WC and to examine the influence of gender and obesity on these relationships among Japanese schoolchildren.

Methods

Subjects included 3,750 schoolchildren from the fourth and seventh grade in Ina-town, Saitama Prefecture, Japan between 2004 and 2008. Information about subject's age, sex, height, weight, %BF, and WC was collected from annual physical examinations. %BF was measured with a bipedal biometrical impedance analysis device. Obesity was defined by the following two criteria: the obese definition of the Centers for Disease Control and Prevention, and the definition of obesity for Japanese children. Pearson's correlation coefficients between BMI and %BF or WC were calculated separately for sex.

Results

Among fourth graders, the correlation coefficients between BMI and %BF were 0.74 for boys and 0.97 for girls, whereas those between BMI and WC were 0.94 for boys and 0.90 for girls. Similar results were observed in the analysis of seventh graders. The correlation coefficient between BMI and %BF varied by physique (obese or non-obese), with weaker correlations among the obese regardless of the definition of obesity; most correlation coefficients among obese boys were less than 0.5, whereas most correlations among obese girls were more than 0.7. On the other hand, the correlation coefficients between BMI and WC were more than 0.8 among boys and almost all coefficients were more than 0.7 among girls, regardless of physique.

Conclusions

BMI was positively correlated with %BF and WC among Japanese schoolchildren. The correlations could be influenced by obesity as well as by gender. Accordingly, it is essential to consider gender and obesity when using BMI as a surrogate for %BF and WC for epidemiological use.

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.

Métodos de avaliação da composição corporal em crianças

OBJETIVO: Revisar as principais técnicas de avaliação da composição corporal de crianças, enfatizando os estudos de validação. FONTES DE DADOS: Foi realizada uma busca nas principais bases científicas em saúde (SciELO, Science Direct e Pubmed), utilizando-se os descritores: "validação", "composição corporal", "criança", "índice de massa corporal", "pesagem hidrostática", "plestimografia", "bioimpedância elétrica", "pregas cutâneas", "antropometria", "circunferência da cintura" e respectivos vocábulos em inglês e espanhol. Foram selecionados artigos publicados entre 1990 e 2007e trabalhos clássicos referentes ao tema, publicados anteriormente. SÍNTESE DOS DADOS: Os métodos indiretos mais utilizados para avaliação da composição corporal de crianças são a plestimografia e a absortometria radiológica de dupla energia. Dentre os métodos duplamente indiretos, os mais utilizados são o índice de massa corporal, as pregas cutâneas, a bioimpedância elétrica, a circunferência da cintura, a relação cintura/quadril, o índice de conicidade e a relação cintura/estatura, sendo que as maiores correlações encontradas foram para a bioimpedância elétrica e o índice de massa corporal. CONCLUSÕES: Existem vários métodos para avaliar a composição corporal em crianças, cada um com suas vantagens e desvantagens. Ao definir o melhor método, é preciso eleger aquele que melhor detecte o problema que se pretende corrigir, levando em consideração os custos, o nível de treinamento dos avaliadores, o tempo de execução, a receptividade da população e os possíveis riscos à saúde.

Comparison of dual-energy X-ray absorptiometry, air displacement plethysmography and bioelectrical impedance analysis for the assessment of body composition in severely obese Caucasian children and adolescents

The objectives of the present study were to compare body composition assessed by dual-energy X-ray absorptiometry (DXA), air displacement plethysmography (ADP) and bioelectrical impedance analysis (BIA) in severely obese Caucasian children and adolescents and to develop and validate new equations for predicting body composition from BIA using DXA as the reference method. Body composition was assessed in fifty-eight obese children and adolescents (BMI 34·4 (sd 4·9) kg/m2) aged 10–17 years by DXA, ADP and BIA. ADP body fat content was estimated from body density using equations devised by Siri (ADPSiri) and Lohman (ADPLohman). In the whole sample, the Bland–Altman test showed that ADPSiri and ADPLohman underestimated percentage fat mass (%FM) by 2·1 (sd 3·4) and by 3·8 (sd 3·3) percent units (P < 0·001), respectively, compared to DXA. In addition, compared to DXA, BIA underestimated %FM by 5·8 (sd 4·6) percent units in the whole group (P < 0·001). A new prediction equation (FFM (kg) = 0·87 × (stature2/body impedance)+3·1) was developed on the pooled sample and cross-validated on an external group of sixty-one obese children and adolescents. The difference between predicted and measured FFM in the external group was − 1·6 (sd 2·9) kg (P < 0·001) and FFM was predicted accurately (error < 5 %) in 75 % of subjects. In conclusion, DXA, ADP and the BIA are not interchangeable for the assessment of %FM in severely obese children and adolescents. The new prediction equation offers an alternative approach to DXA for the estimation of body composition in severely obese children and adolescents.

Percent body fat measured by BIA and DEXA in obese, African-American adolescent girls

OBJECTIVE

To compare the estimation of body fat between bioelectrical impedance analysis (BIA) and dual energy X-ray absorptiometry (DEXA) in overweight, African-American female adolescents.

SUBJECTS

In total, 54 African-American adolescent female subjects were recruited for Study 1. Each adolescent's body mass index was greater than the 85th percentile and their average body fat was 45% according to DEXA. A total of 26 African-American adolescent female subjects were available for Study 2, and had an average body fat of 26% according to DEXA.

MEASUREMENTS

Percent body fat was measured by DEXA and BIA. Seven different BIA equations were tested. Both sets of data were analyzed using Bland-Altman regression analyses, utilizing percent body fat measured by DEXA as the criterion.

RESULTS

The Kushner equation provided estimates that were unaffected by body fat in both studies. Estimates were unbiased when applied to the exclusively overweight sample and biased when utilized with the separate sample of normal weight and obese girls. The remaining equations were biased, provided inconsistent estimates across body weight, or were biased and provided inconsistent estimates. Ethnicity-specific and ethnicity-combined equations performed similarly in the obese sample, but became more disparate when applied to a sample encompassing a wider body weight range. The limits of agreement between all BIA equations and the DEXA estimates ranged from 6 to 9%.

CONCLUSION

The study suggests that the Kushner BIA equation is appropriate for use with African-American female adolescents across the weight spectrum, while the majority of BIA equations underestimated percent body fat as body fat increased.

Comparison of multifrequency bioelectrical impedance analysis with dual-energy X-ray absorptiometry for assessment of percentage body fat in a large, healthy population

BACKGROUND

Bioelectrical impedance analysis (BIA) is widely used in clinics and research to measure body composition. However, the results of BIA validation with reference methods are contradictory, and few data are available on the influence of adiposity on the measurement of body composition by BIA.

OBJECTIVE

The goal was to determine the effects of sex and adiposity on the difference in percentage body fat (%BF) predicted by BIA compared with dual-energy X-ray absorptiometry (DXA).

DESIGN

A total of 591 healthy subjects were recruited in Newfoundland and Labrador. %BF was predicted by using BIA and was compared with that measured by DXA. Methods agreement was assessed by Pearson's correlation and Bland and Altman analysis. Differences in %BF among groups based on sex and adiposity were analyzed by using one-factor analysis of variance with Bonferroni correction.

RESULTS

Correlations between BIA and DXA were 0.88 for the whole population, 0.78 for men, and 0.85 for women. The mean %BF determined by BIA (32.89 +/- 8.00%) was significantly lower than that measured by DXA (34.72 +/- 8.66%). The cutoffs were sex specific. BIA overestimated %BF by 3.03% and 4.40% when %BF was <15% in men and <25% in women, respectively, and underestimated %BF by 4.32% and 2.71% when %BF was >25% in men and >33% in women, respectively.

CONCLUSIONS

BIA is a good alternative for estimating %BF when subjects are within a normal body fat range. BIA tends to overestimate %BF in lean subjects and underestimate %BF in obese subjects.

Percentiles of body composition from bioelectrical impedance and body measurements in U.S. adolescents 8-17 years old: Project HeartBeat!

Reference percentiles (5th, 10th, 50th, 85th, 90th, and 95th) of black and nonblack children ages 8-17 years from Project HeartBeat! (n = 678) are presented for body mass index (BMI), percent body fat (PBF), fat-free mass (FFM), and fat mass (FM) derived from bioelectrical impedance. Project HeartBeat! is a mixed longitudinal study in which three cohorts of children (seen initially at age 8, 11, or 14 years) were followed for 4 years and measured thrice-yearly from 1991 through 1995. Weight, height, and BMI of Project HeartBeat! children are similar in central tendency and variability to those of nationally representative samples for nonblack children but not black children, for whom there is an excess of children at or above the 95th percentile for weight and BMI. Values of PBF above which cardiovascular risk variables increase (as suggested in the literature) are located at the 85th percentile of the Project HeartBeat! distributions. This percentile of PBF may be tentatively considered as a cutoff point with epidemiological significance for children.

Effects of physical activity, body fat, and salivary cortisol on mucosal immunity in children

This study examined relationships among physical activity, body composition, and stress- and immunity-related variables in fifth grade children (10-11 yr) in Southern Ontario. The 29 boys and 32 girls, who participated in the study, performed a 20-m shuttle run for prediction of aerobic fitness. Bioelectrical impedance was used to assess relative body fat. Standardized questionnaires were used to determine physical activity-related variables and frequency of upper respiratory tract infection (URTI). Resting saliva samples were collected and tested for resting cortisol and resting secretory immunoglobulin A (SIgA). Subjects wore a pedometer for 48 h to estimate their average total distance traveled per day. SIgA was significantly correlated with reported URTIs but was not related to salivary cortisol, physical activity, fitness level, or relative body fat. Children who spent more time in sport activities and had higher aerobic fitness reported fewer "sick" days. Children with body fat higher than 25% reported significantly (P < 0.05) more sick days than the rest of the cohort. There were no gender differences in SIgA, URTI frequency, and cortisol levels. The test-retest reproducibility for salivary cortisol was 0.66 (P < 0.01), whereas long-term SIgA reproducibility was nonsignificant for repeated measurements taken after 6 wk. Resting secretory immunity was not strongly related to fitness and physical activity, but there was evidence that reduced physical activity and excess body fat can result in higher URTI incidence.

Physical and pubertal development in young male gymnasts

The purpose of this study was to evaluate the effect of intense training on physical growth and sexual maturation in young male gymnasts. Physical development, pubertal development, testosterone levels, energy expenditure, and relative body fat were examined in 21 circumpubertal male gymnasts (13.3 +/- 0.3 yr) and 24 age-matched controls (13.5 +/- 0.3 yr). Subjects completed a self-assessment of genital and pubic hair development with the use of the Tanner scale. All subjects were measured for height, weight, and salivary testosterone levels (T). The Physical Activity Questionnaire for Adolescents was used to estimate weekly energy expenditure in metabolic equivalents. Percent body fat (%BF) was assessed by using bioelectrical impedance analysis. Developmental stages and T, as well as height and weight, were not different between groups. Energy expenditure was significantly higher (P <or= 0.05) and %BF was lower (P <or= 0.05) in athletes than in controls, but lean body mass was not significantly different between groups. Energy expenditure was negatively correlated (P <or= 0.05) with %BF but not related to T. Developmental stages were strongly (P <or= 0.05) related to T but not to energy expenditure or %BF. It is concluded that, although there is a higher energy expenditure accompanying intense training in young male athletes, their body composition is not necessarily affected, and there is no determined effect on their physical and pubertal development.

Changes in fat mass, fat-free mass and aerobic fitness in severely obese children and adolescents following a residential treatment programme

The purpose of this study was to describe changes in fat mass (FM), fat-free mass (FFM) and aerobic fitness in severely obese children and adolescents during residential treatment in the Medical Paediatric Centre Zeepreventorium. Treatment consisted of moderate dietary restriction, physical activity and psychological support. This study was a clinical observation of 20 severely obese children and adolescents (8 boys and 12 girls, aged 15.4+/-1.8 years) who completed the 10-month residential programme. Height, weight, FM, FFM and aerobic fitness was measured four times during the intervention: at baseline, 11 weeks, 24 weeks and at 33 weeks (at the end of the programme ). The mean decrease in level of overweight was 46% (P<0.001), with a mean loss of 8.9% FM (P<0.001). Submaximal performance (PWC150) improved from 123+/-35 Watt to 152+/-37 Watt (P<0.001). Maximal performance levels increased (performance time: from 14+/-2.9 min to 15.3+/-3.5 min, peak power: from 186+/-38 Watt to 205+/-45 Watt, P<0.01) without an improvement in absolute VO(2 peak).

CONCLUSION

A moderate dietary restriction in combination with physical activity and psychological support in severely obese children and adolescents is effective in decreasing body fat and improving physical performance. Further research is needed to evaluate the longer-term effects of such a programme.

Serum leptin concentration in young adult women with ovulatory dysfunction

To investigate the functional role of leptin in human ovulation, we measured serum leptin, LH, FSH and estradiol in 16 young adult women suffering from ovulatory dysfunction with BMI ranging from 17.5 to 24.5 (group A). The control subjects included 12 women with regular ovulation and matched age and BMI (group B). We found that serum leptin concentration in group A subjects was significantly lower than that in group B subjects (4.1+/-0.5 vs. 6.1+/-0.4 ng/ml, p<0.01). The percent body fat, estradiol, LH and FSH concentrations in groups A and B were not significantly different. These results indicate that anovulatory young adult women have lower leptin concentration than women with regular ovulation, thus suggesting a key role for leptin in regular ovulation or ovulatory dysfunction.

Bodyfat percentage in girls increased steadily with age and percentile rank of body mass index

BACKGROUND

The purpose of the present study was to determine the body composition of elementary school children by bioelectrical impedance analysis (BIA) method with a subject in a standing position. The method is frequently used in Japan. The other aim was to evaluate the relationship between the body composition and percentile rank of the body mass index (BMI) in Japanese children.

METHODS

The number of subjects were 1042 children (530 boys and 512 girls aged from 6- to 12-years-old) from an elementary school. The bioelectrical impedance (BI) in the standing position was measured late in the morning before lunch. The fat percentage was derived from the body density according to the formula of Brozek et al. Each percentile value of BMI for each age and sex was determined from the frequency table of height and weight published by the Ministry of Education in Japan.

RESULTS

The fat percentage in both boys and girls was significantly correlated with the BMI, however, girls showed a closer linear relation than boys. The fat percentage in girls increased steadily with age and percent rank of the BMI. The fat percentage in boys was scattered in a wide range at each percentile rank of the BMI.

CONCLUSIONS

The fat percentage measured by the BIA in the standing position is closely associated with the percentile rank of the BMI in elementary school girls. For boys, it will be necessary to compare data among different types of BI measurement methods.

Body composition in prepubertal girls: comparison of six methods

OBJECTIVE

To compare estimates of fat mass (FM), fat-free mass (FFM) and percentage body fat (%fat) by six different methods in prepubertal girls.

DESIGN

Cross-sectional study.

SUBJECTS

Normal-weight, multi-ethnic, prepubertal girls (age=8.5+/-0.4 y, n=101).

MEASUREMENTS

Body composition was measured in each child by anthropometry (skinfold thickness using Slaughter equation), dual-energy X-ray absorptiometry (DXA), total body potassium (TBK), isotope dilution for total body water measurement (TBW), multifrequency bioelectrical impedance spectroscopy (BIS), and total body electrical conductivity (TOBEC).

RESULTS

TOBEC and skinfold thickness yielded the lowest values of FM followed by DXA, TBK, TBW and BIS, with BIS giving the highest value of FM. All methods were significantly different for FFM, FM and %fat (P<0.001), except FFM by DXA and TBK. The Bland-Altman limits of agreement among the methods reveal that they are not directly interchangeable for FM, FFM, or %fat. The largest mean difference for FM was between TOBEC and BIS (-2.90 kg), whereas the smallest mean difference was between TOBEC and skinfold thickness (-0.14 kg). For FFM, the largest mean difference was also between TOBEC and BIS (2.83 kg), but the smallest mean difference for FFM was between DXA and TBK (-0.03 kg). For %fat, the mean differences were larger, -10.5% for TOBEC and BIS and+9.7% for skinfold thickness and BIS. The closest two techniques for %fat were TOBEC and skinfold thickness (mean difference of -0.62%) and DXA and TBK (-1.81%).

CONCLUSIONS

We found that estimates of body composition in prepubertal 8-y-old girls are highly method-dependent and that the six methods studied (DXA, TBK, TBW, TOBEC, BIS and anthropometry) are not directly interchangeable.

Underestimation of percentage fat mass measured by bioelectrical impedance analysis compared to dual energy X-ray absorptiometry method in obese children

OBJECTIVE

The aim of the study was to investigate whether there is a difference between body fat mass percentage measured by BIA and DXA method.

DESIGN

Transversal study, randomized.

SETTING

Lipid and Obesity Outpatient Clinic, Department of Pediatrics, University of Vienna, Austria.

SUBJECTS

Twenty-seven children and adolescents from the Lipid and Obesity Outpatient Clinic, Department of Pediatrics, University of Vienna, were included in the study (14 boys and 13 girls between 6 and 18 y; mean age 12.6 and 13.1 y).

METHODS

The body fat percentage was measured with BIA (bioelectrical impedance analyzer BIA 2000-M) and DXA (dual energy X-ray absorptiometry) methods on the same day.

RESULTS

The mean difference between the body fat mass percentage measured by BIA and DXA was 4.48 with a standard deviation of 2.93. The results measured by BIA were almost always lower than that by DXA by about 12%. The lower and upper limit of the difference in 95% confidence interval was -5.64 and -3.32. By paired t-test, these results were significantly different (P<0.001). The correlation between the two measurements was 0.826. The mean percentage of body fat mass measured by BIA was 34.86+/-7.08% and by DXA 39.75+/-5.63%. The differences were not changed by age and body fat percentage but they were by sex.

CONCLUSIONS

The results of the study show that the body fat percentages measured by BIA and DXA method were significantly different. This is very important because BIA technique is a routine technique for clinical purposes. Adjustments to the formula used for calculating the total fat mass in obese children and adolescence are necessary. Underestimation of body fat percentage measured by bioelectrical impedance analysis compared to dual X-ray absorptiometry method in obese children is three times higher with boys than with girls.

Assessing the body composition of 6-17-year-old Black and White girls in field studies

The purpose of the study was to develop ethnic-specific equations for fat-free mass (FFM) from selected anthropometric dimensions and bioelectrical impedance measures of resistance (R) and reactance (Xc) for use in the NHLBI Growth and Heath Study. Using dual-energy X-ray absorptiometry measures of body composition as the dependent variable and field measures of body composition by anthropometry and bioelectrical impedance as the explanatory variables, ethnic-specific prediction equations were developed on a sample of girls representing a wide range of ages and BMI. The equations were cross-validated using (1) the Prediction of Sum of Squares (PRESS) statistic and (2) an independent sample of 20 girls of each race from a study conducted at the National Institute of Child Health and Human Development (NICHD). Subjects were 65 White and 61 Black girls 6-17 years of age. The best race-specific equations for FFM each explained 99% and 97% of the variance in the White and Black girls, respectively. Root mean square errors (RMSE) ranged from 1.14 to 1.95 kg. The equation for Black girls used Stature2/Resistance (R), weight, and reactance (Xc) as predictor variables; the equation for White girls used Stature2/R, weight, and triceps skinfold thickness. The results indicate that (1) equations to predict FFM in girls should be ethnic-specific and that (2) accurate values for TBF and %BF can be calculated from the predicted FFM.