Estimation of body fatness by air displacement plethysmography in African American and white children

Negative affect and loss-of-control eating in relation to adiposity among non-Hispanic youth identifying as black or white

Negative affect and loss-of-control (LOC)-eating are consistently linked and prevalent among youth identifying as non-Hispanic Black (NHB) and non-Hispanic White (NHW), particularly those with high weight. Given health disparities in high weight and associated cardiometabolic health concerns among NHB youth, elucidating how the association of negative affect with adiposity may vary by racial/ethnic group, and whether that relationship is impacted by LOC-eating, is warranted. Social inequities and related stressors are associated with negative affect among NHB youth, which may place this group at increased risk for excess weight gain. Across multiple aggregated protocols, 651 youth (13.0 ± 2.7 y; 65.9 % girls, 40.7 % NHB; 1.0 ± 1.1 BMIz; 37.6 % LOC-eating) self-reported trait anxiety and depressive symptoms as facets of negative affect. LOC-eating was assessed by interview and adiposity was measured objectively. Cross-sectional moderated mediation models predicted adiposity from ethno-racial identification (NHB, NHW) through the pathway of anxiety or depressive symptoms and examined whether LOC-eating influenced the strength of the pathway, adjusting for SES, age, height, and sex. The association between ethno-racial identity and adiposity was partially mediated by both anxiety (95 % CI = [0.01, 0.05]) and depressive symptoms (95 % CI = [0.02, 0.08]), but the mediation was not moderated by LOC-eating for either anxiety (95 % CI = [-0.04, 0.003]) or depressive symptoms (95 % CI = [-0.07, 0.03]). Mechanisms underlying the link between negative affect and adiposity among NHB youth, such as stress from discrimination and stress-related inflammation, should be explored. These data highlight the need to study impacts of social inequities on psychosocial and health outcomes.

Comparison of Several Prediction Equations Using Skinfold Thickness for Estimating Percentage Body Fat vs. Body Fat Percentage Determined by BIA in 6-8-Year-Old South African Children: The BC-IT Study

Body composition measurement is useful for assessing percentage body fat (%BF) and medical diagnosis, monitoring disease progression and response to treatment, and is essential in assessing nutritional status, especially in children. However, finding accurate and precise techniques remains a challenge. The study compares %BF determined by bioelectrical impedance analysis (BIA) and calculated from available prediction equations based on skinfolds in young South African children. A cross-sectional study performed on 202 children (83 boys and 119 girls) aged 6-8 years. Height and weight, triceps and subscapular skinfolds were determined according to standard procedures. %BF was determined with BIA and three relevant available equations. SPSS analyzed the data using paired samples tests, linear regression, and Bland-Altman plots. Significant paired mean differences were found for BIA and Slaughter (t₂₀₁ = 33.896, p < 0.001), Wickramasinghe (t₂₀₁ = 4.217, p < 0.001), and Dezenberg (t₂₀₁ = 19.910, p < 0.001). For all of the equations, the standards for evaluating prediction errors (SEE) were above 5. The Bland-Altman plots show relatively large positive and negative deviations from the mean difference lines and trends of systematic under- and over-estimation of %BF across the %BF spectrum. All three equations demonstrated a smaller %BF than the %BF measured by BIA, but the difference was smallest with the Wickramasinghe equation. In comparison, a poor SEE was found in the three %BF predicted equations and %BF derived from BIA. As such, an age-specific %BF equation incorporating criterion methods of deuterium dilution techniques or 'gold-standard' methods is needed to refute these findings. However, in the absence of developed %BF equations or 'gold-standard' methods, the available prediction equations are still desirable.

Cross-Sectional and Longitudinal Examination of Insulin Sensitivity and Secretion across Puberty among Non-Hispanic Black and White Children

BACKGROUND

Few studies using criterion measures of insulin sensitivity (SI) and insulin secretory capacity (ISC) have been conducted across puberty to adulthood. We examined how SI and ISC change from pre-puberty through adulthood.

METHODS

Hyperglycemic clamp studies were performed in a convenience sample of non-Hispanic Black (NHB) and White children evaluated at age 6 to 12 years and at approximately 5-year intervals into adulthood (maximum age 27 years). SI and ISC (first-phase and steady-state insulin secretion) were determined cross-sectionally in 133 unique participants across puberty and in adulthood. Additionally, longitudinal changes in SI and ISC were compared at two timepoints among three groups defined by changes in pubertal development: pre-pubertal at baseline and late-pubertal at follow-up (n=27), early-pubertal at baseline and late-pubertal at follow-up (n=27), and late-pubertal at baseline and adult at follow-up (n=24).

RESULTS

Cross-sectionally, SI was highest in pre-puberty and early puberty and lowest in mid-puberty (analysis of covariance [ANCOVA] P=0.001). Longitudinally, SI decreased from pre-puberty to late puberty (P<0.001), then increased somewhat from late puberty to adulthood. Cross-sectionally, first-phase and steady-state ISC increased during puberty and decreased in adulthood (ANCOVA P<0.02). Longitudinally, steady-state and first-phase ISC increased from pre-puberty to late puberty (P<0.007), and steady-state ISC decreased from late puberty to adulthood. The NHB group had lower SI (P=0.003) and greater first-phase and steady-state ISC (P≤0.001), independent of pubertal development.

CONCLUSION

This study confirms that SI decreases and ISC increases transiently during puberty and shows that these changes largely resolve in adulthood.

Children and Adolescents' Anthropometrics Body Composition from 3-D Optical Surface Scans

OBJECTIVE

This study aimed to explore the accuracy and precision of three-dimensional optical (3DO) whole-body scanning for automated anthropometry and estimating total and regional body composition.

METHODS

Healthy children and adolescents (n = 181, ages 5-17 years) were recruited for the Shape Up! Kids study. Each participant underwent whole-body dual-energy x-ray absorptiometry and 3DO scans; multisite conventional tape measurements served as the anthropometric criterion measure. 3DO body shape was described using automated body circumference, length, and volume measures. 3DO estimates were compared with criterion measures using simple linear regression by the stepwise selection method.

RESULTS

Of the 181 participants, 112 were used for the training set, 49 were used for the test set, and 20 were excluded for technical reasons. 3DO body composition estimates were strongly associated with dual-energy x-ray absorptiometry measures for percent body fat, fat mass, and fat-free mass (R2 : 0.83, 0.96, and 0.98, respectively). 3DO provided reliable measurements of fat mass (coefficient of variation, 3.30; root mean square error [RMSE], 0.53), fat-free mass (coefficient of variation, 1.34; RMSE, 0.53 kg), and percent body fat (RMSE = 1.2%).

CONCLUSIONS

3DO surface scanning provides accurate and precise anthropometric and body composition estimates in children and adolescents with high precision. 3DO is a safe, accessible, and practical method for evaluating body shape and composition in research and clinical settings.

Relationships of Trait Anxiety and Loss of Control Eating with Serum Leptin Concentrations among Youth

Loss of control (LOC) eating in youth is associated with elevated fasting serum leptin, even after accounting for adiposity. Anxiety is closely linked to, and may exacerbate, LOC eating. Yet, it remains unclear how anxiety relates to leptin, or if the relationship is moderated by the presence of LOC eating. We examined whether self-reported trait anxiety interacted with LOC eating in relation to leptin in a convenience sample of youths (n = 592; 13.1 ± 2.7 years; body mass index z-score (BMIz) = 0.9 ± 1.1; 61.8% girls; 53.5% non-Hispanic White; 36.6% with LOC eating). LOC eating was assessed by interview. Leptin was measured after an overnight fast. Exploratory analyses were conducted to examine anxiety and LOC eating in relation to laboratory intake patterns in three sub-samples. In a generalized linear model adjusting for relevant covariates, anxiety significantly interacted with LOC eating in relation to leptin (p = 0.02), such that greater trait anxiety related to higher concentrations of leptin only among youth with LOC eating. Trait anxiety was not significantly related to fasting serum leptin independently in a generalized linear model adjusting for age, race, height, sex, study type, and fat mass (kg). Exploratory mechanistic analyses of food intake patterns did not identify consistent results for participants with both anxiety and LOC eating. Among youth with LOC eating, anxiety may be associated with higher serum leptin. Prospective data are required to elucidate the directionality and mechanisms of these relationships.

Pediatric Loss-of-Control Eating and Anxiety in Relation to Components of Metabolic Syndrome

Objective

Pediatric loss-of-control (LOC) eating is associated with, and predictive of, gains in adiposity and adverse metabolic outcomes. In addition, some preliminary data suggest that anxiety may exacerbate the relationship of LOC eating with weight and metabolic syndrome (MetS)-related measures. We therefore examined whether anxiety moderated the relationship between LOC eating and body mass index z (BMIz), adiposity, and MetS-related measures in youth.

Methods

A convenience sample of non-treatment-seeking boys and girls of varying weight strata were interviewed to determine the presence of LOC eating and completed a questionnaire assessing trait anxiety. BMIz and MetS-related measures (blood pressure, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, glucose, and insulin) were measured after an overnight fast. Adiposity was assessed by air displacement plethysmography or dual-energy x-ray absorptiometry. Analyses adjusted for age, sex, race, height, fat mass, and depressive symptoms, as appropriate.

Results

In all, 379 youths (13.0 ± 2.8 years; 53% female; BMIz = 0.8 ± 1.1; 22% with LOC eating) were studied. Anxiety was not significantly related to BMIz, adiposity, or MetS-related measures. However, anxiety and LOC eating interacted such that only among youth with LOC eating, anxiety was positively associated with fasting insulin (p = .02) and insulin resistance (p = .01). The interaction of anxiety and LOC eating was not significantly related to BMIz, adiposity, or any other MetS-related measure (ps = ns).

Conclusions

Only among non-treatment-seeking youth with LOC eating, anxiety may be associated with increased insulin secretion and insulin resistance. Longitudinal studies are required to confirm these findings and explore mechanisms for these relationships.

An examination of the associations between pediatric loss of control eating, anxiety, and body composition in children and adolescents

BACKGROUND

Data on the link between anxiety and body composition in youth are mixed. Yet, anxiety and disordered eating are highly correlated. One pathway between anxiety and excess body weight and fat mass may be through loss of control (LOC) eating. We examined whether LOC eating mediated the relationship between anxiety and body composition in youth with and without overweight.

METHOD

Non-treatment-seeking youth (8-17 years) participated in studies examining weight and eating behaviors. Anxiety (child- and parent-report of child) and LOC eating were assessed by self-report questionnaires and interviews, respectively. Fat mass was assessed by dual-energy x-ray absorptiometry or air displacement plethysmography. Cross-sectional mediation models with bias-corrected bootstrap confidence intervals (CI) were conducted.

RESULTS

257 youth (12.91 ± 2.76 years; 52.5% female; BMI-z 0.93 ± 1.07) were studied. There was a significant indirect path between child-reported anxiety and both BMI-z (ab = .005, SE = 0.003, 95% CI = 0.001-0.01) and body fat mass (ab = 0.001, SE = 0.001, 95% CI ≤0.001-0.003) through the number of LOC episodes in the past month. No significant indirect paths through the number of LOC episodes was observed for parent-report of child anxiety on BMI-z (ab = 0.004, SE = 0.01, 95% CI = -0.01-0.03) or body fat mass (ab = 0.001, SE = 0.002, 95% CI = -0.002-0.01). No direct paths were observed between anxiety and body composition regardless of the informant.

DISCUSSION

LOC eating appears to mediate the relationship of child-reported anxiety with body composition in non-treatment seeking boys and girls. Prospective data are needed to determine if anxiety promotes LOC eating that results in increased risk for excess body weight and fat gain.

Agreement Between Standard Body Composition Methods to Estimate Percentage of Body Fat in Young Male Athletes

PURPOSE

To examine the intermethods agreement of dual-energy X-ray absorptiometry (DXA) and foot-to-foot bioelectrical impedance analysis (BIA) to assess the percentage of body fat (%BF) in young male athletes using air-displacement plethysmography (ADP) as the reference method.

METHODS

Standard measurement protocols were carried out in 104 athletes (40 swimmers, 37 footballers, and 27 cyclists, aged 12-14 y).

RESULTS

Age-adjusted %BF ADP and %BF BIA were significantly higher in swimmers than footballers. ADP correlates better with DXA than with BIA (r = .84 vs r = .60, P < .001). %BF was lower when measured by DXA and BIA than ADP (P < .001), and the bias was higher when comparing ADP versus BIA than ADP versus DXA. The intraclass correlation coefficients between DXA and ADP showed a good to excellent agreement (r = .67-.79), though it was poor when BIA was compared with ADP (r = .26-.49). The ranges of agreement were wider when comparing BIA with ADP than DXA with ADP.

CONCLUSION

DXA and BIA seem to underestimate %BF in young male athletes compared with ADP. Furthermore, the bias significantly increases with %BF in the BIA measurements. At the individual level, BIA and DXA do not seem to predict %BF precisely compared with ADP in young athletic populations.

Associations of adolescent emotional and loss of control eating with 1-year changes in disordered eating, weight, and adiposity

OBJECTIVE

Adolescent emotional-eating, referring to eating in response to negative affective states, is frequently reported by those with loss of control (LOC) eating. Although LOC eating has been shown to predict exacerbated disordered eating and excess weight/adiposity gain, the extent to which emotional-eating, either alone or in combination with LOC, predicts adverse outcomes has not been determined. Thus, we examined associations of baseline emotional-eating with changes in disordered eating, BMI, and adiposity over 1-year, and to what degree the presence or absence of baseline LOC moderated these associations.

METHODS

189 non-treatment-seeking youth (15.4 ± 1.4y; 66% female; 67% non-Hispanic White, 38% overweight [BMI ≥ 85th %ile]) completed the emotional-eating Scale for Children/Adolescents and the Eating Disorder Examination interview at baseline and again at 1-year. Air displacement plethysmography assessed adiposity at both time points.

RESULTS

Baseline emotional-eating alone was not significantly associated with the development of objective binge eating or changes in disordered eating attitudes, BMI or adiposity 1-year later. However, baseline emotional-eating interacted with the presence of baseline LOC in the prediction of 1-year outcomes. Among adolescents with LOC eating, greater baseline emotional-eating was related to increased disordered eating attitudes (p = .03), BMI (p = .04), and adiposity (p = .04) at 1-year, after correcting for false discovery rate.

DISCUSSION

Emotional-eating among youth also reporting LOC was associated with adverse outcomes over 1-year. Adolescents who report both behaviors may represent a subset of individuals at especially high risk for exacerbated disordered eating and excess weight gain. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:551-560).

Emotion dysregulation and loss-of-control eating in children and adolescents

OBJECTIVE

To examine the associations among self-reported loss-of-control (LOC) eating, emotion dysregulation, body mass, and objective energy intake among youth. Emotion dysregulation may be 1 individual factor that promotes excess energy intake and increases in body mass among youth with LOC eating.

METHOD

Children and adolescents (N = 230; 8 to 17 years) enrolled in a nonintervention study completed a structured interview to determine the presence or absence of self-reported LOC eating. Children's emotion dysregulation was assessed via parent-report with the Child Behavior Checklist. Youth also completed 2 test meals to capture "binge" and "normal" eating. Body composition was examined using air displacement plethysmography.

RESULTS

After controlling for relevant covariates, youth with self-reported LOC eating had higher parent-reported emotion dysregulation than those without LOC. Parent-reported emotion dysregulation was also associated with greater observed energy intake (after accounting for body mass), as well as higher fat mass. Emotion dysregulation also moderated associations between LOC status/gender and body mass variables; among youth with self-reported LOC eating and girls, those with high parent-described emotion dysregulation (vs. low) had significantly higher fat mass and BMIz.

CONCLUSIONS

Data from the current study suggest that emotion dysregulation may play a role in energy intake and obesity, particularly among youth with self-reported LOC eating and girls. Additional studies are needed to identify the prospective mechanisms linking poor emotion regulation and LOC eating. These mechanisms, in turn, may inform future interventions targeting excess energy intake and obesity in pediatric samples. (PsycINFO Database Record

Metabolic characteristics of youth with loss of control eating

PURPOSE

Preliminary data in adults suggest that binge eating is associated with greater prevalence of metabolic syndrome (MetS) components. However, there are limited data in youth, and little is known of the role of binge episode size in these relationships.

METHODS

We examined the relationship between loss of control eating and metabolic characteristics in a convenience sample of 329 treatment-seeking and non-treatment-seeking adolescent boys and girls. The sample was enriched by design with adolescents who were overweight or obese and with individuals who reported episodes of loss of control over their eating (either objectively large binge episodes, OBEs or subjectively large binge episodes, SBEs, in the past month), as assessed by clinical interview. MetS components (blood pressure, lipids, glucose, and waist circumference) were the primary variables of interest.

RESULTS

46% of the cohort reported loss of control eating; among those, 53% reported SBEs only and 47% reported OBEs. Youth with loss of control eating had higher systolic blood pressure (p=.001) and higher low-density lipoprotein cholesterol (LDL-c) (p=.002) compared to those without loss of control eating, in analyses adjusted for intervention-seeking status, fat mass and sociodemographic characteristics. Youth reporting OBEs had higher LDL-c (p=.013) compared to those reporting only SBEs.

CONCLUSIONS

Adolescents reporting loss of control episodes had greater dysfunction in some components of the MetS compared to youth without loss of control; episode size may contribute to metabolic dysfunction.

A prospective study of adolescent eating in the absence of hunger and body mass and fat mass outcomes

OBJECTIVE

Eating in the absence of hunger (EAH) refers to the consumption of palatable foods in a sated state. It has been proposed that EAH promotes excess weight gain in youth; yet there are limited prospective data to support this hypothesis. We examined whether EAH at baseline predicted increases in body mass (BMI and BMIz) and fat mass (kg) 1 year later among adolescent boys and girls.

METHODS

EAH was assessed as adolescents' consumption of palatable snack foods following eating to satiety from an ad libitum lunch buffet. Parents also completed a questionnaire about their children's EAH. Body composition was assessed using air displacement plethysmography.

RESULTS

Of 196 adolescents assessed for EAH at baseline, 163 (83%) were re-evaluated 1 year later. Accounting for covariates, which included respective baseline values for each dependent variable, race, height, age, sex, and pubertal stage, there were no significant associations between baseline observed or parent-reported EAH and change in adolescent BMI, BMIz, or fat mass. Results did not differ by sex, child weight status, or maternal weight status.

CONCLUSIONS

No evidence was found to support the hypothesis that EAH is a unique endophenotype for adolescent weight or fat gain.

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.

Analysis of variants and mutations in the human winged helix FOXA3 gene and associations with metabolic traits

BACKGROUND/OBJECTIVES

The forkhead factor Foxa3 is involved in the early transcriptional events controlling adipocyte differentiation and plays a critical function in fat depot expansion in response to high-fat diet regimens and during aging in mice. No studies to date have assessed the potential associations of genetic variants in FOXA3 with human metabolic outcomes.

SUBJECTS/METHODS

In this study, we sequenced FOXA3 in 392 children, adolescents and young adults selected from several cohorts of subjects recruited at the National Institute of Child Health and Human Development of the National Institutes of Health based on the availability of dual-energy X-ray absorptiometry data, magnetic resonance imaging scans and DNA samples. We assessed the association between variants present in these subjects and metabolic traits and performed in vitro functional analysis of two novel FOXA3 missense mutations identified.

RESULTS

Our analysis identified 14 novel variants and showed that the common single-nucleotide polymorphism (SNP) rs28666870 is significantly associated with greater body mass index, lean body mass and appendicular lean mass (P values 0.009, 0.010 and 0.013 respectively). In vitro functional studies showed increased adipogenic function for the FOXA3 missense mutations c.185C>T (p.Ser62Leu) and c.731C>T (p.Ala244Val) compared with FOXA3-WT.

CONCLUSIONS

Our study identified novel FOXA3 variants and mutations, assessed the adipogenic capacity of two novel missense alterations in vitro and demonstrated for the first time the associations between FOXA3 SNP rs28666870 with metabolic phenotypes in humans.

Puberty and the manifestations of loss of control eating in children and adolescents

OBJECTIVE

We investigated the manifestations of pediatric loss of control (LOC) eating at different stages of pubertal development.

METHOD

Participants were a nonclinical sample of 468 youth (8-17 years). Physical examination determined pubertal stage. LOC eating and disordered eating attitudes were assessed with the Eating Disorder Examination. In a randomized crossover design, a subset (n = 244) ate ad libitum from two test meals designed to capture normal and LOC eating.

RESULTS

There were no differences in the prevalence rates or frequency of reported LOC eating episodes across pubertal stages (ps ≥ 0.50). There were, however, puberty by LOC eating interactions in disordered eating attitudes and palatable food consumption (ps ≤ .05), even after adjusting for age and body composition. LOC eating was associated with elevated global disordered eating attitudes, weight concern, and shape concern in post-pubertal youth (ps ≤ .001), but not pre-pubertal youth (ps ≥ .49). In late-puberty, youth with LOC eating consumed less energy from protein (p < .001) and more from carbohydrate (p = .003) and snack-type foods (p = .02) than those without LOC eating, whereas endorsement of LOC eating in pre- or early-to-mid-puberty was not associated with differences in eating behavior (ps ≥ 0.20).

CONCLUSIONS

Findings suggest that puberty may be a critical risk period, when LOC eating behaviors in boys and girls may become accompanied by greater weight and shape concerns and more obesogenic food consumption patterns. Interventions for LOC eating during pre-puberty should be evaluated to determine if they are particularly beneficial for the prevention of exacerbated eating disorder psychopathology and adverse weight outcomes.

Depressive symptoms and observed eating in youth

Depressive symptoms in youth may be a risk factor for obesity, with altered eating behaviors as one possible mechanism. We tested whether depressive symptoms were associated with observed eating patterns expected to promote excessive weight gain in two separate samples. In Study 1, 228 non-treatment-seeking youth, ages 12-17y (15.3±1.4y; 54.7% female), self-reported depressive symptoms using the Beck Depression Inventory. Energy intake was measured as consumption from a 10,934-kcal buffet meal served at 11:00am after an overnight fast. In Study 2, 204 non-treatment-seeking youth, ages 8-17y (13.0±2.8y; 49.5% female), self-reported depressive symptoms using the Children's Depression Inventory. Energy intake was measured as consumption from a 9835-kcal buffet meal served at 2:30pm after a standard breakfast. In Study 1, controlling for body composition and other relevant covariates, depressive symptoms were positively related to total energy intake in girls and boys. In Study 2, adjusting for the same covariates, depressive symptoms among girls only were positively associated with total energy intake. Youth high in depressive symptoms and dietary restraint consumed the most energy from sweets. In both studies, the effects of depressive symptoms on intake were small. Nevertheless, depressive symptoms were associated with significantly greater consumption of total energy and energy from sweet snack foods, which, over time, could be anticipated to promote excess weight gain.

Serum leptin and loss of control eating in children and adolescents

BACKGROUND

Both insufficiency and resistance to the actions of the adipocyte-derived hormone leptin promote hunger, increased food intake and greater body weight. Some studies suggest that adults reporting binge eating have increased serum leptin compared with those without binge eating, even after adjusting for the greater adiposity that characterizes binge eaters. Pediatric binge or loss of control (LOC) eating are prospective risk factors for excessive weight gain and may predict development of metabolic abnormalities, but whether LOC eating is associated with higher leptin among children is unknown. We therefore examined leptin and LOC eating in a pediatric cohort.

METHODS

A convenience sample of 506 lean and obese youth (7-18 years) was recruited from Washington, DC and its suburbs. Serum leptin was collected after an overnight fast. Adiposity was measured by dual-energy X-ray absorptiometry or air displacement plethysmography. LOC eating was assessed by interview methodology.

RESULTS

Leptin was strongly associated with fat mass (r=0.79, P<0.001). However, even after adjusting for adiposity and other relevant covariates, youth with LOC eating had higher serum leptin compared with those without LOC episodes (15.42±1.05 vs 12.36±1.04 ng ml(-1), P<0.001). Neither reported amount of food consumed during a recent LOC episode nor number of LOC episodes in the previous month accounted for differences in leptin (P>0.05). The relationship between LOC eating and leptin appeared to be significant for females only (P=0.002).

CONCLUSIONS

Reports of LOC eating were associated with higher fasting leptin in youth, beyond the contributions of body weight. Prospective studies are required to elucidate whether LOC eating promotes greater leptin or whether greater leptin resistance may promote LOC eating.

Links of adolescent- and parent-reported eating in the absence of hunger with observed eating in the absence of hunger

OBJECTIVE

Eating in the absence of hunger (EAH) typically was assessed by measuring snack intake after consumption of a meal. There were no validated self-report measures of EAH. The relationship of adolescent self-report and parent-reported EAH to adolescents' measured intake in the absence of hunger was examined.

DESIGN AND METHODS

Ninety adolescents completed the Eating in the Absence of Hunger Questionnaire for Children and Adolescents (EAH-C) to describe eating when not hungry. Parents described children's EAH on a parallel version designed for parents (EAH-P). In a randomized crossover study, adolescent EAH in response to external cues was measured as snack intake after a lunch meal standardized to provide 50% of daily energy requirements and after a large array (>10,000 kcal).

RESULTS

Parents' reports of children's EAH in response to external cues were associated with greater EAH after both meals, adjusting for body composition, sex, age, race, puberty, and meal intake. Adolescent-reported EAH was unrelated or showed an inverse association with observed EAH.

CONCLUSIONS

Parent-reported EAH showed a positive association with adolescents' observed EAH and may be a useful research and clinical tool for assessing EAH in response to external cues in conditions when laboratory assessments are not feasible.

Sociocultural pressures and adolescent eating in the absence of hunger

Parental feeding practices and sociocultural pressures theoretically influence eating behavior. Yet, whether these factors relate to eating in the absence of hunger (EAH) is unknown. We assessed if sociocultural pressures were associated with EAH among 90 adolescents (Mage=15.27, SD=1.39; 48% female). Parents completed the Child Feeding Questionnaire. Adolescents completed the Perceived Sociocultural Pressures Scale, Sociocultural Attitudes Towards Appearance Questionnaire-3, and Multidimensional Body Self-Relations Questionnaire-Appearance Scales. On two occasions, EAH was assessed as snack food intake after adolescents ate to satiety. Controlling for body composition and demographics, parental restriction and family pressure to be thin were associated with greater EAH. Media pressure was related to more EAH in girls. Appearance orientation and preoccupation with becoming overweight mediated links between sociocultural pressures and EAH. Findings support the notion that sociocultural pressures and their links to body image may contribute to the course of disinhibited eating behaviors during adolescence.

Effects of a low glycemic load or a low-fat dietary intervention on body weight in obese Hispanic American children and adolescents: a randomized controlled trial

BACKGROUND

In Hispanic children and adolescents, the prevalence of obesity and insulin resistance is considerably greater than in non-Hispanic white children. A low-glycemic load diet (LGD) has been proposed as an effective dietary intervention for pediatric obesity, but to our knowledge, no published study has examined the effects of an LGD in obese Hispanic children.

OBJECTIVE

We compared the effects of an LGD and a low-fat diet (LFD) on body composition and components of metabolic syndrome in obese Hispanic youth.

DESIGN

Obese Hispanic children (7-15 y of age) were randomly assigned to consume an LGD or an LFD in a 2-y intervention program. Body composition and laboratory assessments were obtained at baseline and 3, 12, and 24 mo after intervention.

RESULTS

In 113 children who were randomly assigned, 79% of both groups completed 3 mo of treatment; 58% of LGD and 55% of LFD subjects attended 24-mo follow-up. Compared with the LFD, the LGD decreased the glycemic load per kilocalories of reported food intakes in participants at 3 mo (P = 0.02). Both groups had a decreased BMI z score (P < 0.003), which was expressed as a standard z score relative to CDC age- and sex-specific norms, and improved waist circumference and systolic blood pressure (P < 0.05) at 3, 12, and 24 mo after intervention. However, there were no significant differences between groups for changes in BMI, insulin resistance, or components of metabolic syndrome (all P > 0.5).

CONCLUSIONS

We showed no evidence that an LGD and an LFD differ in efficacy for the reduction of BMI or aspects of metabolic syndrome in obese Hispanic youth. Both diets decreased the BMI z score when prescribed in the context of a culturally adapted, comprehensive weight-reduction program.

Air displacement plethysmography, dual-energy X-ray absorptiometry, and total body water to evaluate body composition in preschool-age children

Anthropometrics and body mass index are only proxies in the evaluation of adiposity in the pediatric population. Air displacement plethysmography technology was not available for children aged 6 months to 9 years until recently. Our study was designed to test the precision of air displacement plethysmography (ADP) in measuring body fat mass in children at ages 3 to 5 years compared with a criterion method, deuterium oxide dilution (D(2)O), which estimates total body water and a commonly used methodology, dual-energy x-ray absorptiometry (DXA). A prospective, cross-sectional cohort of 66 healthy children (35 girls) was recruited in the central Arkansas region between 2007 and 2009. Weight and height were obtained using standardized procedures. Fat mass (%) was measured using ADP, DXA, and D(2)O. Concordance correlation coefficient and Bland-Altman plots were used to investigate the precision of the ADP techniques against D(2)O and DXA in children at ages 3 to 5 years. ADP concordance correlation coefficient for fat mass was weak (0.179) when compared with D(2)O. Bland-Altman plots revealed a low accuracy and large scatter of ADP fat mass (%) results (mean=-2.5, 95% CI -20.3 to 15.4) compared with D(2)O. DXA fat mass (%) results were more consistent although DXA systematically overestimated fat mass by 4% to 5% compared with D(2)O. Compared with D(2)O, ADP does not accurately assess percent fat mass in children aged 3 to 5 years. Thus, D(2)O, DXA, or quantitative nuclear magnetic resonance may be considered better options for assessing fat mass in young children.

Child-Specific Thoracic Gas Volume Prediction Equations for Air-Displacement Plethysmography

OBJECTIVE

To develop child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography in 6- to 17-year-old children.

RESEARCH METHODS AND PROCEDURES

Study 1 developed TGV prediction equations using anthropometric variables after completing a measured TGV and air-displacement plethysmography test in 224 healthy boys and girls (11.2 +/- 3.2 years, 45.3 +/- 18.7 kg, 149.9 +/- 18.5 cm). Study 2 cross-validated the prediction equations in a separate cohort of 62 healthy boys and girls (11.2 +/- 3.4 years, 44.2 +/- 15.3 kg, 149.4 +/- 19.3 cm).

RESULTS

In Study 1 (development of TGV prediction equations), the quadratic relationship using height as the independent variable and the measured TGV as the dependent variable yielded the highest adjusted R(2) and the lowest SE of estimate in both genders, thus producing the following prediction equations: TGV = 0.00056 x H(2) - 0.12422 x H + 8.15194 (boys) and TGV = 0.00044 x H(2) - 0.09220 x H + 6.00305 (girls). In Study 2 (cross-validation), no significant difference between the predicted and measured TGVs (-0.018 +/- 0.377 liters) was observed. The regression between the measured TGV and the predicted TGV yielded a slope and intercept that did not significantly differ from the line of identity. Prediction accuracy was good as indicated by a high R(2) (0.862) and low SE of estimate (0.369 liters).

DISCUSSION

The new child-specific TGV prediction equations accurately, precisely, and without bias estimated the actual TGV of 6- to 17-year-old children.

Binge eating and weight-related quality of life in obese adolescents

Limited data exist regarding the association between binge eating and quality of life (QOL) in obese adolescent girls and boys. We, therefore, studied binge eating and QOL in 158 obese (BMI ≥ 95th percentile) adolescents (14.5 ± 1.4 years, 68.0% female, 59% African-American) prior to weight-loss treatment. Youth completed an interview to assess binge eating and a questionnaire measure of QOL. Controlling for body composition, binge eating youth (n = 35), overall, reported poorer QOL in domains of health, mobility, and self-esteem compared to those without binge eating (ps < 0.05). Also, girls, overall, reported poorer QOL than boys in activities of daily-living, mobility, self-esteem, and social/interpersonal functioning (ps < 0.05). Girls with binge eating reported the greatest impairments in activities of daily living, mobility, self-esteem, social/interpersonal functioning, and work/school QOL (ps < 0.05). Among treatment-seeking obese adolescents, binge eating appears to be a marker of QOL impairment, especially among girls. Prospective and treatment designs are needed to explore the directional relationship between binge eating and QOL and their impact on weight outcomes.

Air-displacement plethysmography for the measurement of body composition in children aged 6-48 months

INTRODUCTION

Air-displacement plethysmography (ADP) is an age-appropriate method for measuring relative fat mass (%FM) in children; however, the accuracy of this method has not been evaluated in children aged 5 y or younger.

RESULTS

Mean %FM values measured by ADP (17.9 ± 8.0%) and by total body water (TBW) (23.7 ± 6.3%) were significantly different (P < 0.001). Regression analysis of %FM by ADP vs. TBW provided a line of best fit with a slope of 0.089, r(2) = 0.013, and standard error of the estimate (SEE) = 6.3% FM (P = 0.40).

DISCUSSION

The error was related to child weight and %FM, but not to behaviors (movement or vocalizations) occurring during the test sequence. A large portion of the error was attributable to imprecision in measuring small volumes. As currently designed, ADP is not an accurate method for measuring %FM in young children. Further investigation of the sources of variability will provide insight into ways of improving the accuracy of this technology for this population.

METHODS

This study examined the accuracy of an ADP system modified for young children (BOD POD; Life Measurement, Concord, CA) by comparing %FM results from ADP with those obtained from TBW by deuterium (D(2)O) dilution (reference method) in 72 children aged 6-48 mo.

Independent benefits of meeting the 2008 physical activity guidelines to insulin resistance in obese latino children

We examined the independent association between moderate-to-vigorous physical activity (MVPA) and insulin resistance (IR) among obese Latino children (N = 113; 7-15 years) who were enrolled in a community-based obesity intervention. Baseline information on physical activity was gathered by self-report. Clinical assessments of body composition, resting energy expenditure (REE), as well as glucose and insulin responses to an oral glucose tolerance test (OGTT) were performed after an overnight fast. Insulin resistance was defined as a 2 h insulin concentration >57 μU·mL(-1). We observed that those obese children who met the 2008 Guidelines for MVPA (≥60 min/day) experienced a significantly lower odds of IR compared with those not meeting the Guidelines (OR = 0.29; 95% CI: (0.10-0.92)) and these findings were independent of age, sex, pubertal stage, acculturation, fasting insulin, and 2 h glucose concentrations. Efforts to promote 60 min or more of daily MVPA among children from ethnic minority and high-risk communities should assume primary public health importance.

Effects of high and low glycemic load meals on energy intake, satiety and hunger in obese Hispanic-American youth

Some short-term pediatric studies have suggested beneficial effects of low glycemic load (LGL) meals on feelings of hunger and on energy intake. However, the effects of LGL diets have not been systematically studied in obese Hispanic children, who stand to benefit from successful interventions.

OBJECTIVE

To examine the effects of LGL and high-GL (HGL) meals on appetitive responses and ad libitum energy intake of obese Hispanic youth.

METHODS

A total of 88 obese Hispanic youth aged 7-15 years were enrolled in a community-based obesity intervention program and randomly assigned to consume meals designed as either LGL (n = 45) or HGL (n = 43). After 12 weeks, participants were admitted for a 24-hour metabolic study. Following the morning test meal, subjects serially reported hunger, fullness, and satiety using a visual analog scale. Blood insulin and glucose were measured. After 5 hours, participants were fed another test meal and given a snack platter from which to eat ad libitum. All test food was weighed and the energy, macronutrients, and glycemic load (GL) of consumed foods were calculated.

RESULTS

The HGL group had significantly higher insulin (p = 0.0005) and glucose (p = 0.0001) responses to the breakfast meal compared with the LGL group. There were no significant between-group differences in energy consumed from the snack platter (1303 vs. 1368 kcal, p = 0.5), or in the subjective feelings of hunger (p = 0.3), fullness (p = 0.5) or satiety (p = 0.3) between the two groups.

CONCLUSIONS

Our study provides no evidence that, for obese Hispanic youth, changing the GL of the diet affects short-term hunger, fullness, satiety, or energy intake. ClinicalTrials.gov Identifier: NCT01068197.

Salience of loss of control for pediatric binge episodes: does size really matter?

OBJECTIVE

The subjective experience of loss of control (LOC) during eating, independent of overeating, may be a salient marker of disordered eating and risk for overweight in youth. However, few studies have directly tested this notion in an adequately powered sample.

METHOD

Three-hundred-sixty-seven youth (M ± SD age = 12.7 ± 2.8 y) were categorized as reporting objective binge eating (OBE; 12.5%), subjective binge eating (SBE; 11.4%), objective overeating without LOC (OO; 18.5%), or no episodes (NE; 57.5%). Disordered eating attitudes, general psychopathology, and adiposity were assessed.

RESULTS

Children with OBE and SBE generally did not differ in their disordered eating attitudes, emotional eating, eating in the absence of hunger, depressive and anxiety symptoms, or adiposity. However, both OBE and SBE youth had significantly greater disordered eating attitudes, emotional eating, eating in the absence of hunger, depressive and anxiety symptoms, and adiposity compared to those with OO or NE (ps < .05).

DISCUSSION

For non-treatment-seeking youth, LOC during eating episodes, rather than episode size, appears to be the most salient marker of eating and weight problems.

Eating in the absence of hunger in adolescents: intake after a large-array meal compared with that after a standardized meal

BACKGROUND

Eating in the absence of hunger (EAH) is typically assessed by measuring youths' intake of palatable snack foods after a standard meal designed to reduce hunger. Because energy intake required to reach satiety varies among individuals, a standard meal may not ensure the absence of hunger among participants of all weight strata.

OBJECTIVE

The objective of this study was to compare adolescents' EAH observed after access to a very large food array with EAH observed after a standardized meal.

DESIGN

Seventy-eight adolescents participated in a randomized crossover study during which EAH was measured as intake of palatable snacks after ad libitum access to a very large array of lunch-type foods (>10,000 kcal) and after a lunch meal standardized to provide 50% of the daily estimated energy requirements.

RESULTS

The adolescents consumed more energy and reported less hunger after the large-array meal than after the standardized meal (P values < 0.001). They consumed ≈70 kcal less EAH after the large-array meal than after the standardized meal (295 ± 18 compared with 365 ± 20 kcal; P < 0.001), but EAH intakes after the large-array meal and after the standardized meal were positively correlated (P values < 0.001). The body mass index z score and overweight were positively associated with EAH in both paradigms after age, sex, race, pubertal stage, and meal intake were controlled for (P values ≤ 0.05).

CONCLUSION

EAH is observable and positively related to body weight regardless of whether youth eat in the absence of hunger from a very large-array meal or from a standardized meal. This trial was registered at clinicaltrials.gov as NCT00631644.

Psychological symptoms and insulin sensitivity in adolescents

PURPOSE

Symptoms of psychological distress have been linked to low insulin sensitivity in adults; however, little is known about this relationship in pediatric samples. We therefore examined symptoms of depression and anxiety in relation to insulin sensitivity in adolescents.

METHODS

Participants were 136 non-treatment-seeking, healthy adolescents (53.2% female) of all weight strata (BMI-z = 1.08 +/- 1.08) between the ages of 12 and 18 years (M = 15.16,SD = 1.55). Adolescents completed questionnaire measures assessing depression and anxiety symptoms. Fasting blood samples for serum insulin and plasma glucose were obtained to estimate insulin sensitivity with the quantitative insulin sensitivity check index. Fat mass and fat-free mass were measured with air displacement plethysmography or dual-energy X-ray absorptiometry.

RESULTS

Depressive symptoms were associated with higher fasting insulin and decreased insulin sensitivity even after controlling for fat mass, fat-free mass, height, age, pubertal status, race, and sex (p < 0.01).

CONCLUSIONS

As has been described for adults, depressive symptoms are associated with low insulin sensitivity among healthy adolescents. Further experimental and prospective studies are required to determine the directionality of this link.

Puberty and observed energy intake: boy, can they eat!

BACKGROUND

Anecdotal reports suggest that adolescent males consume large quantities of food to meet the growth demands of pubertal development. However, limited experimental data exist to support this impression.

OBJECTIVE

The objective was to measure energy intakes of youth at different pubertal stages.

DESIGN

Participants were 204 volunteers (50.5% male) aged 8-17 y. Pubertal development was categorized by physical examination into prepuberty (males: testes < 4 mL; females: Tanner breast stage 1), early-mid puberty (males: testes = 4-12 mL; females: Tanner breast stages 2-3), or late puberty (males: testes >12 mL; females: Tanner breast stages 4-5). Energy intake was measured as consumption from a 9835-kcal food array during 2 lunch time meals.

RESULTS

Males consumed more energy than did females across all pubertal stages (P < 0.001). Intake increased with pubertal development (P < 0.001), but the timing and magnitude of change varied by sex (P = 0.02). Males' unadjusted energy intake was greater in late puberty (mean +/- SE: 1955 +/- 70 kcal) than in prepuberty (1287 +/- 90 kcal) or early-mid puberty (1413 +/- 92 kcal) (P < 0.001). Females' unadjusted energy intake tended to be lower among prepubertal girls (905 +/- 140 kcal) than among females in early-mid puberty (1278 +/- 82 kcal, P = 0.07) or late puberty (1388 +/- 68 kcal, P = 0.01). After adjustment for fat-free mass, fat mass, height, overweight status, race, and meal instruction, the main effect of sex (P < 0.001) remained significant, but the effect of puberty was not significant (P = 0.66).

CONCLUSIONS

The observed intake patterns are congruent with known sexual dimorphisms for body composition, peak growth velocity, and pubertal development. Consistent with their higher energy requirements, males can consume significantly larger amounts of food than females, especially during later puberty. This trial was registered at clinicaltrials.gov as NCT00320177.

Energy intake and energy expenditure among children with polymorphisms of the melanocortin-3 receptor

BACKGROUND

Homozygosity for 2 protein-altering polymorphisms in the melanocortin-3 receptor gene (MC3R) coding sequence, C17A and G241A, has been reported to be associated with an obesity phenotype in children, yet how these polymorphisms affect energy homeostasis is unknown. Association between adult body weight and +2138InsCAGACC, another variant in the 3' untranslated region of MC3R, has also been described.

OBJECTIVE

The objective of this study was to examine associations of C17A + G241A and +2138InsCAGACC MC3R variants with children's energy balance.

DESIGN

Children aged 6-19 y were genotyped for MC3R C17A, G241A, and +2138InsCAGACC. Subjects underwent studies of energy intake from a 9835-kcal food array (n = 185), resting energy expenditure (REE) by using indirect calorimetry (n = 302), or total daily energy expenditure (TEE) by using doubly labeled water (n = 120). Linear regression was used to examine the associations between MC3R polymorphisms and the measures of energy balance.

RESULTS

Body mass index and fat mass were greater in those with double homozygosity for C17A + G241A (P = 0.001). After accounting for covariates (including body composition), the number of minor C17A + G241A alleles was associated with significantly greater energy intake (beta = +0.15, P = 0.02) but not altered REE or TEE. No significant associations were observed between +2138InsCAGACC and measures of either fat mass or energy balance.

CONCLUSIONS

C17A + G241A polymorphisms may be associated with pediatric obesity because of greater energy intake rather than because of diminished energy expenditure. +2138InsCAGACC does not appear to be associated with obesity or measures of energy balance in children.

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.

Insulin resistance, hyperinsulinemia, and energy intake in overweight children

OBJECTIVE

To examine the relationship between energy intake during a buffet meal and indexes of insulin dynamics in overweight children.

STUDY DESIGN

Ninety-five nondiabetic, overweight (body mass index > or = 95th percentile) children (age 10.3 +/- 1.4 years) selected lunch from a 9835-kcal buffet eaten ad libitum after an overnight fast. The associations between energy intake and measures of insulin dynamics, in the postabsorptive state and during a 2-hour hyperglycemic clamp, were determined. Covariates in the statistical model included race, sex, skeletal age, fat-free mass, fat mass, socioeconomic status, and number of foods in the buffet rated as acceptable.

RESULTS

Energy intake was positively associated with the fasting homeostasis model assessment for insulin resistance index (beta = 0.24, P = .042), fasting insulin/glucose ratio (beta = 0.24, P = .044), first-phase insulin (beta = 0.23, P = .032), and first-phase C-peptide (beta = 0.21, P = .046); energy intake was negatively associated with clamp-derived insulin sensitivity (beta = -0.29, P = .042). Each 10% decrease in clamp-derived insulin sensitivity predicted a 27-kcal greater energy intake.

CONCLUSIONS

Insulin resistance and hyperinsulinemia are associated with greater energy intake after an overnight fast in overweight children. These associations suggest mechanisms whereby insulin resistance may contribute to excessive weight gain in children.

Psychometric properties of a new questionnaire to assess eating in the absence of hunger in children and adolescents

BACKGROUND

Eating in the absence of hunger (EAH), studied in the context of laboratory paradigms, has been associated with obesity and is predictive of excess weight gain in children. However, no easily administered questionnaire exists to assess for EAH in children.

OBJECTIVE

We developed an Eating in the Absence of Hunger Questionnaire to be administered to children and adolescents (EAH-C) and examined psychometric properties of the measure.

DESIGN

Two-hundred and twenty-six obese (BMI > or = 95th percentile for age and sex, n=73) and non-obese (BMI<95th percentile, n=153) youth (mean age+/-S.D., 14.4+/-2.5 y) completed the EAH-C and measures of loss of control and emotional eating, and general psychopathology. Temporal stability was assessed in a subset of participants.

RESULTS

Factor analysis generated three subscales for the EAH-C: Negative Affect, External Eating, and Fatigue/Boredom. Internal consistency for all subscales was established (Cronbach's alphas: 0.80-0.88). The EAH-C subscales had good convergent validity with emotional eating and loss of control episodes (p's<0.01). Obese children reported higher Negative Affect subscale scores than non-obese children (p</=0.05). All three subscales were positively correlated with measures of general psychopathology. Intra-class correlation coefficients revealed temporal stability for all subscales (ranging from 0.65 to 0.70, p's<0.01). We conclude that the EAH-C had internally consistent subscales with good convergent validity and temporal stability, but may have limited discriminant validity. Further investigations examining the EAH-C in relation to laboratory feeding studies are required to determine whether reported EAH is related to actual energy intake or to the development of excess weight gain.

Physical activity intensity and risk of overweight and adiposity in children

BACKGROUND

Physical activity recommendations for children focus on duration of activity and underemphasize intensity.

OBJECTIVE

To evaluate the relationship between physical activity (intensity and duration) and the odds of being overweight, >20% body fat and >25% body fat.

METHODS AND PROCEDURES

Body fat, BMI and physical activity (accelerometry) were measured in children (n = 251) aged 8-10 years. Physical activity was quantified as time in moderate physical activity (MPA) and vigorous physical activity (VPA).

RESULTS

Prevalence of overweight and obesity were 18 and 11.6%, respectively. Regression indicated that VPA, not MPA, is associated with body fat (r = 0.35, P < 0.001) and BMI (r = 0.26, P < 0.001). Odds ratio demonstrated a significant impact of MPA and VPA on body composition. Children performing < or =5 min/day of VPA are 4.0 times more likely to have > or =20% body fat (P < 0.001), 2.9 times more likely to have > or =25% body fat (P < 0.05) and 5.2 times more likely to be classified as overweight (P < 0.01) compared to children performing > or =15 min/day. Those performing < or =15 min/day of MPA vs. >45 min/day MPA are at 4.2 increased odds of having > or =20% body fat (P < 0.001), and 3.0 increased odds of having > or =25% (P < 0.01).

DISCUSSION

Lower durations of both MPA and VPA are associated with increased odds of overweight and adiposity. Forty-five minutes of MPA and fifteen minutes of VPA were associated with reduced body fat and BMI. We recommend that these amounts are used to develop minimum physical activity intensity guidelines for the prevention and treatment of obesity.

Oxygen-uptake efficiency slope as a determinant of fitness in overweight adolescents

PURPOSE

Peak oxygen uptake (VO2peak) is frequently difficult to assess in overweight individuals; therefore, submaximal measures that predict VO2peak are proposed as substitutes. Oxygen uptake efficiency slope (OUES) has been suggested as a submaximal measurement of cardiorespiratory fitness that is independent of exercise intensity. There are few data examining its value as a predictor of V O2peak in severely overweight adolescents.

METHODS

One hundred seven severely overweight (BMI Z 2.50 +/- 0.34) and 43 nonoverweight (BMI Z 0.13 +/- 0.84) adolescents, performed a maximal cycle ergometer test with respiratory gas-exchange measurements. OUES was calculated through three exercise intensities: lactate inflection point (OUES LI), 150% of lactate inflection point (OUES 150), and VO2peak (OUES PEAK).

RESULTS

When adjusted for lean body mass, VO2peak and OUES at all exercise intensities were lower in overweight subjects (VO2peak: 35.3 +/- 6.4 vs 46.8 +/- 7.9 mL.kg(-1) LBM.min(-1), P < 0.001; OUES LI: 37.9 +/- 10.0 vs 43.7 +/- 9.2 mL.kg(-1) LBM.min(-1).logL(-1) P < 0.001; OUES 150: 41.6 +/- 9.0 vs 49.8 +/- 11.1 mL.kg(-1) LBM.min(-1).logL(-1) P < 0.001; and OUES PEAK: 45.1 +/- 8.7 vs 52.8 +/- 9.6 mL.kg(-1) LBM.min(-1).logL(-1) P < 0.001). There was a significant increase in OUES with increasing exercise intensity in both groups (P < 0.001). OUES at all exercise intensities was a significant predictor of VO2peak for both groups (r2 = 0.35-0.83, P < 0.0001). However, limits of agreement for predicted VO2peak relative to actual VO2peak were wide (+/- 478 to +/- 670 mL.min(-1)).

CONCLUSIONS

OUES differs significantly in overweight and nonoverweight adolescents. The wide interindividual variation and the exercise intensity dependence of OUES preclude its use in clinical practice as a predictor of VO2peak.

Objective assessment of childhood adherence to Canadian physical activity guidelines in relation to body composition

Low levels of childhood physical activity (PA) are a contributing factor to obesity. The objective of this study was to determine the adherence of children to PA guidelines in relation to body composition. Body fat (Slaughter equation) and body mass index (BMI) were determined during the school year (n = 251, ages 8-11 y). Daily energy expenditure (EE, kcal.kg-1.d-1) and activity time (AT, min.d-1) above moderate and vigorous intensity thresholds were assessed (accelerometry). Using EE criteria, 35.9% expended < 3.0 kcal.kg-1.d-1, 27.9% expended between 3.0 and 5.9 kcal.kg-1.d-1, 13.5% expended between 6.0 and 7.9 kcal.kg-1.d-1, and 22.9% expended >or= 8.0 kcal.kg-1.d-1. Using AT criteria, 52.2% accumulated < 30.0 min, 31.1% accumulated 30.0-59.9 min, 12.7% accumulated 60.0-89.9 min, and 4.0% accumulated >or=90.0 min of AT. The EE corresponding to accumulation of AT > 90 min was 14.8 kcal.kg-1.d-1. The AT corresponding to >or= 8 kcal.kg-1.d-1 was 73.0 min. Inverse relationships were observed between EE and body fat (p = 0.0004), BMI (p = 0.002), mass (p = 0.008), and fat mass index (FMI) (p = 0.001), as well as between AT and body fat (p = 0.001), BMI (p = 0.008), mass (p = 0.017), and FMI (p = 0.002). Controlling for BMI, FMI was inversely related to EE (p = 0.049) and AT (p = 0.039). Fat-free mass index and AT were positively related (p = 0.038). Physical activity had beneficial effects on body composition for children independent of BMI. The relationship between AT and daily EE guidelines was rationalized (60 min.d-1 with 8 kcal.kg-1.d-1) and demonstrated association with acceptable body composition. The 60 min.d-1 of moderate activity may be a more suitable initial target than 90 min.d-1, as so few children met the upper tiers of PA guidelines.

Children's descriptions of the foods consumed during loss of control eating episodes

Binge and loss of control (LOC) eating appear to be common among youth; however, little is known about the foods consumed during such eating episodes. Two-hundred forty-nine children, age 6-18 years, were interviewed to determine if they engaged in eating episodes with LOC over the past month. In the absence of reported LOC eating, overeating episodes or normal meals without LOC were recorded. Participants were asked to describe the type and quantity of foods eaten during an episode. Eighty-one children reported LOC eating episodes and 168 reported no such episodes (No LOC). Although total energy intake did not differ between LOC and No LOC episodes, LOC episodes consisted of a lower percentage of calories from protein (14.2+/-0.7 v. 18.0+/-0.7%, p<.001) and a higher percentage from carbohydrates (49.8+/-1.6 v. 45.2+/-1.1%, p<.05). Specifically, LOC episodes consisted of a higher percentage of calories from snacks (13.2+/-2.7 v. 7.4+/-1.2%, p<.05) and desserts (18.1+/-3.1 v. 12.8+/-1.5%, p<.05). The quality of LOC episodes may help explain why LOC eating promotes excessive weight gain among children who report such episodes.

Validation of the emotional eating scale adapted for use in children and adolescents (EES-C)

OBJECTIVE

Eating in response to negative emotions is associated with binge or loss of control (LOC) eating in adults. Although children report engaging in LOC eating, data on emotional eating among youth are limited.

METHOD

We adapted the adult Emotional Eating Scale (Arnow et al., Int J Eat Disord, 18, 79-90, 1995) to be used with children and adolescents (EES-C). Fifty-nine overweight (BMI > or = 95th percentile for age and sex) and 100 non-overweight (BMI 5th-94th percentile) participants (mean age +/- SD 14.3 +/- 2.4 years) completed the EES-C, and measures of recent LOC eating and general psychopathology. Test-retest reliability was assessed in 64 children over a 3.4 +/- 2.6 month interval.

RESULTS

A factor analysis generated three subscales: eating in response to anxiety, anger, and frustration (EES-C-AAF), depressive symptoms (EES-C-DEP), and feeling unsettled (EES-C-UNS). Internal consistency for the subscales was established; Cronbach's alphas for the EES-C-AAF, EES-C-DEP, and EES-C-UNS were 0.95, 0.92, and 0.83, respectively. The EES-C had good convergent validity: children reporting recent LOC eating episodes scored higher on all subscales (p's < 0.05). The EES-C-AAF and EES-C-UNS subscales demonstrated good discriminant validity and the EES-C-DEP revealed adequate discriminant validity. Intra-class correlation coefficients revealed good temporal stability for each subscale (EES-C-AAF = 0.59, EES-C-DEP = 0.74, EES-C-UNS = 0.66; p's < 0.001).

CONCLUSION

The EES-C has good convergent and discriminant validity, and test-retest reliability for assessing emotional eating in children. Further investigation is required to clarify the role emotional eating may play in children's energy intake and body weight.

Methodological agreement between two-compartment body-composition methods in children

Increases in childhood obesity have emphasized the importance of accurate and accessible body composition assessment, especially in monitoring prevention and treatment efforts. Previous pediatric studies, comparing measures from air-displacement plethysmography (ADP) to dual-energy X-ray absorptiometry (DXA) and anthropometry (ANTH, skinfold measures), were performed in small numbers of children or in children across large age and body-size ranges. The objectives of this study were: 1) to compare body fat percentage (%BF), fat mass (FM), and fat-free mass (FFM) from ADP with DXA and ANTH, to determine the agreement between techniques; 2) to identify factors that influence agreement or lack of agreement; and 3) to determine if the agreement is constant over a range of body fatness. Healthy children (n = 125), 7-10 years old, participating in a longitudinal pediatric bone health study, were evaluated. Body composition was assessed by ADP, DXA, and ANTH to determine %BF, FM, and FFM. ADP underestimated %BF compared to DXA and ANTH by 5.0% and 1.4%, respectively. Agreement between techniques was influenced by body fatness, height, age, and gender (all P < 0.05). Relatively good agreement was observed between ADP and both DXA and ANTH for FM and FFM. In conclusion, the underestimation of %BF by ADP compared to DXA may be of a magnitude that is clinically significant, especially when using %BF in children to confirm a diagnosis of obesity. Further development of body-composition techniques for young children need to account for variability in age, gender, and level of fatness.

Statistical validation of air-displacement plethysmography for body composition assessment in children

BACKGROUND

Body composition assessment of children has been hindered by the absence of a safe, quick, and easily tolerated gold standard technique. Existing validation studies of air-displacement plethysmography (ADP) have been based on small, narrowly defined samples, using simple linear regression or Bland-Altman analyses.

AIM

Correlations within a multitrait-multimethod matrix (MTMM) and factor analytic methodologies were used to evaluate ADP as a valid and reliable body composition technique for children.

SUBJECTS AND METHODS

Fat mass (FM), fat-free mass (FFM) and per cent body fat (%BF) were measured in 139 children, 7-10 years old, by ADP, dual energy X-ray absorptiometry (DXA) and anthropometry (ANTH). MTMM and factor analysis were used to compare assessment techniques.

RESULTS

Reliability estimates were lower for ADP than for either ANTH or DXA. Convergent and discriminant correlations between ADP and ANTH or DXA were high for identical as well as non-identical measures. Two body composition factors (Fatness, Leanness) and two technique-related factors (Bod Pod, Anthropometry) were identified.

CONCLUSION

ADP offers a valid and reliable means of assessing body composition in children but does not perform as well as ANTH or DXA. MTMM and factor analytic methodologies offer an effective alternative to assessing body composition.

Effects of binge eating on satiation, satiety, and energy intake of overweight children

BACKGROUND

Children who report episodes of binge eating gain more weight than do children not reporting binge eating. However, how binge eating affects children's food intake at meals is unknown.

OBJECTIVE

We compared the energy intake and postmeal satiety of children with and without a history of binge eating during buffet meals.

DESIGN

Sixty overweight children aged 6-12 y were categorized into those reporting past binge-eating episodes (n = 10) and those reporting no such episodes (n = 50). Children selected lunch twice from a multiple-item, 9835 kcal, buffet meal: after an overnight fast and after a standardized breakfast. Children ate ad libitum, until they reported they were full. The main outcome measures were energy intake during meals and duration of postmeal satiety, after adjustment for covariates, including age, race, sex, socioeconomic status, and body composition.

RESULTS

After the overnight fast, children in the binge-eating group consumed more energy [x (+/-SD): 1748 +/- 581 compared with 1309 +/- 595 kcal; P = 0.04] and exhibited a shorter satiety duration (194 +/- 84 compared with 262 +/- 89 min; P = 0.03) than did children in the non-binge-eating group. After the standardized breakfast, binge-eating children reported a shorter satiety duration (75 +/- 62 compared with 132 +/- 62 min; P = 0.01) and consumed more energy at the postbreakfast meal (1874 +/- 560 compared with 1275 +/- 566 kcal; P = 0.004).

CONCLUSION

The ability to consume large quantities of palatable foods, coupled with decreased subsequent satiety, may play a role in the greater weight gain found in binge-eating children.

Serum brain-derived neurotrophic factor concentrations in lean and overweight children and adolescents

CONTEXT

Brain-derived neurotrophic factor (BDNF) and its receptor appear to be important components of the leptin-signaling cascade involved in energy homeostasis, and mice with BDNF or TrkB gene haploinsufficiency have excessive adiposity. Little is known about the relationship between adiposity and BDNF, particularly in children.

OBJECTIVE

The objective of the study was to study the association of serum BDNF with measures of adiposity in children.

DESIGN/SETTING/PATIENTS

BDNF was determined by a sandwich-type ELISA after an overnight fast in convenience sample of 328 subjects, aged 3-19 yr enriched for extreme obesity. In 43, BDNF was also measured before, and again 1 h after, consuming a high-energy content (787 kcal) milkshake.

MAIN OUTCOME MEASURES

Measures included associations between BDNF and measures of adiposity.

RESULTS

There were no significant univariate associations between log BDNF and adiposity measured by body mass index (BMI), BMI-Z score, or fat mass. However, in an analysis of covariance accounting for age, sex, race, pubertal status, and platelet count, BDNF was lower in overweight children (mean +/- sd, 39.8 +/- 24.8 vs. 47.0 +/- 25.4 ng/dl, P = 0.03); in multiple regression analyses with log BDNF as the dependent variable, BMI (P = 0.03), BMI-Z (P = 0.01), and body fat (P < 0.02) were all negatively associated with BDNF once age, pubertal status, and platelet count were included in the model. Ingestion of a meal did not significantly alter serum BDNF 1 h later (P = 0.26).

CONCLUSIONS

Serum BDNF is lower in extremely overweight children and adolescents than those of normal weight. It remains to be determined whether obese individuals with low serum BDNF for age and platelet count have mutations that alter BDNF function.

Validity of new child-specific thoracic gas volume prediction equations for air-displacement plethysmography

BACKGROUND

To determine the validity of the recently developed child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography (ADP) in diverse pediatric populations.

METHODS

Three distinct populations were studied: European American and African American children living in Birmingham, Alabama and European children living in Lisbon, Portugal. Each child completed a standard ADP testing protocol, including a measured TGV according to the manufactures software criteria. Measured TGV was compared to the predicted TGV from current adult-based ADP proprietary equations and to the recently developed child-specific TGV equations of Fields et al. Similarly, percent body fat, derived using the TGV prediction equations, was compared to percent body fat derived using measured TGV.

RESULTS

Predicted TGV from adult-based equations was significantly different from measured TGV in girls from each of the three ethnic groups (P < 0.05), however child-specific TGV estimates did not significantly differ from measured TGV in any of the ethnic or gender groups. Percent body fat estimates using adult-derived and child-specific TGV estimates did not differ significantly from percent body fat measures using measured TGV in any of the groups.

CONCLUSION

The child-specific TGV equations developed by Fields et al. provided a modest improvement over the adult-based TGV equations in an ethnically diverse group of children.

Modifiable environmental and behavioral determinants of overweight among children and adolescents: report of a workshop

The number of children at risk for overweight and the number of overweight children are increasing and have become a serious public health concern. Interventions that could be applied at the population level have not been proven effective. The development of effective strategies is thought to be hampered by the lack of understanding of which behavioral and environmental factors need to be modified. On June 14 and 15, 2004, the NIH held a meeting of experts to discuss the issue of modifiable determinants of obesity in children and adolescents. Included were presentations on interventions among children that have been proven effective, dietary and physical activity behavioral determinants, physical, social, and family environmental determinants, and the quality of measures of determinants and correlates of overweight.

Total body protein mass: validation of total body potassium prediction model in children and adolescents

Protein is an important body component for monitoring growth, development, and nutritional status. We previously developed a total body potassium (TBK, in mmol) and bone mineral (Mo, in kg) model for predicting total body protein (TBPro, in kg) in adults (TBPro = 0.00252 x TBK + 0.732 x Mo). However, the applicability of the TBK-Mo model for children is unknown. The study aims were to develop a TBK-independent 6-component (6-C) TBPro approach as the criterion, and then to validate the TBK-Mo model in children. The following measurements were made in adolescents and children (n = 62, 38 boys and 24 girls, aged 5-17 y): body weight (BW, in kg), body volume (BV, in liters) by air displacement plethysmography, total body water (TBW, in kg) by 2H2O dilution, Mo by dual-energy X-ray absorptiometry, and TBK by whole-body counting. A 6-C model was derived as TBPro = 2.922 x BW - 0.301 x TBW - 2.039 x Mo - 2.632 x BV. The TBPro estimates did not differ between the 6-C and TBK-Mo models (mean +/- SD, 0.20 +/- 0.86 kg). There was a significant correlation between TBPro by the 6-C and TBK-Mo models (r = 0.94, P < 0.001). Bland-Altman analysis indicated that the differences between TBPro by 6-C and TBK-Mo models were not significantly correlated with the mean TBPro estimates by the 2 models (r = 0.032, P > 0.05). The TBK-Mo model can thus be used to estimate TBPro in healthy adults, adolescents, and children > 5 y old.

Effects of a 12-week physical activity protocol delivered by YMCA after-school counselors (Youth Fit for Life) on fitness and self-efficacy changes in 5-12-year-old boys and girls

To address reduced physical education (PE) in elementary schools, a 12-week physical activity protocol was tested on 5-12-year-old, primarily African American, girls (n = 226) and boys (n = 344) at 14 YMCA after-school care sites. The 3 times/week, 45-min session curriculum included cardiovascular, resistance, and flexibility training, in which all children could participate simultaneously, and a behavioral skills education component. After-school counselors, formerly untrained in PE methods, administered the sessions, with periodic supervision by YMCA wellness staff members. Analyses of the eight Age x Sex subsamples indicated significant improvements on body composition, strength, and endurance, both within-groups and when predicted changes due to maturation were accounted for. Exercise barriers self-efficacy significantly increased in subsamples of 9-10- and 11-12-year-old girls only. The need for replication across ethnic groups was suggested. Limitations and the need for extension of research on supplementation of elementary school PE were discussed.

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.

Need for optimal body composition data analysis using air-displacement plethysmography in children and adolescents

Air-displacement plethysmography (ADP) is now widely used for body composition measurement in pediatric populations. However, the manufacturer's software developed for adults leaves a potential bias for application in children and adolescents, and recent publications do not consistently use child-specific corrections. Therefore we analyzed child-specific ADP corrections with respect to quantity and etiology of bias compared with adult formulas. An optimal correction protocol is provided giving step-by-step instructions for calculations. In this study, 258 children and adolescents (143 girls and 115 boys ranging from 5 to 18 y) with a high prevalence of overweight or obesity (28.0% in girls and 22.6% in boys) were examined by ADP applying the manufacturer's software as well as published equations for child-specific corrections for surface area artifact (SAA), thoracic gas volume (TGV), and density of fat-free mass (FFM). Compared with child-specific equations for SAA, TGV, and density of FFM, the mean overestimation of the percentage of fat mass using the manufacturer's software was 10% in children and adolescents. Half of the bias derived from the use of Siri's equation not corrected for age-dependent differences in FFM density. An additional 3 and 2% of bias resulted from the application of adult equations for prediction of SAA and TGV, respectively. Different child-specific equations used to predict TGV did not differ in the percentage of fat mass. We conclude that there is a need for child-specific equations in ADP raw data analysis considering SAA, TGV, and density of FFM.