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1.  Feasibility of Intravenous Glucose Tolerance Testing Prior to Puberty 
1) Report the feasibility of completing the 180 minute FSIVGTT in healthy weight, overweight and obese pre-pubertal children and, 2) describe the finalized FSIVGTT protocol after addendums were implemented to decrease the frequency of mild adverse events and improve test completion rates.
Insulin sensitivity was determined by FSIVGTT.
FSIVGTT was attempted in a total of 22 study participants. Insulin sensitivity was successfully assessed in 15 study participants (8 males, 7 females, 10 Caucasian, 4 African American, 1 Pacific Islander, age range 7-9 years). Mean insulin sensitivity was 15.1±9.8 (mμ/l)-1·min-1 range 4.4 – 43.2 (mμ/l)-1·min-1. Seven study participants, however experienced mild adverse events of hypoglycemia. Several addendums were made to the FSIVGTT protocol to ensure study participant comfort and safety, decrease the frequency of mild adverse events and increase test completion rates.
Addendums made to FSIVGTT protocol allowed successful completion of FSIVGTT in 15 (68%) of the 22 children. These results demonstrate that FSIVGTT is challenging, yet feasible in healthy lean and obese pre-pubertal children.
PMCID: PMC4366942  PMID: 19579147
Insulin Resistance; Insulin Sensitivity; Hypoglycemia; Pre-pubertal Children; glucose tolerance
2.  Association between television viewing and poor diet quality in young children 
To examine the association between television/video (TV) viewing and markers of diet quality among 3-year-old children.
We studied 613 boys and 590 girls, age 3 years old, who were participants in Project Viva. Each mother reported the number of hours her child watched TV on an average weekday and weekend day in the past month, from which we calculated a weighted mean. The main outcomes were intakes of selected foods and nutrients from a validated food frequency questionnaire. In linear regression models we adjusted for mother’s sociodemographic information, parental body mass index (BMI), and child’s age, sex, race/ethnicity, BMI z-score, sleep duration, and breast feeding duration.
Mean (standard deviation, SD) age of subjects was 3.2 (0.2) years; 372 children (31%) were non-white and 151 (13%) had a household income <$40 000, and 330 mothers (28%) had completed less than a college degree. Mean (SD) TV viewing was 1.7 (1.0) hours per day. For each 1-hour increment of TV viewing per day, we found higher intakes of sugar-sweetened beverages (0.06 servings/day [95% CI 0.03, 0.10]), fast food (0.32 servings/month [95% CI 0.16, 0.49]), red and processed meat (0.06 servings/day [95% CI 0.02, 0.09]), total energy intake (48.7 kcal/day [95% CI 18.7, 78.6]), and percent energy intake from trans fat (0.05 [95% CI 0.03, 0.07]). We found lower intakes of fruit and vegetables (−0.18 servings/day [95% CI −0.32, −0.05]), calcium (−24.6 mg/day [95% CI −41.0, −8.1]), and dietary fiber (−0.44 g/day [95% CI −0.65, −0.22]).
Among 3-year-olds, more TV viewing is associated with adverse dietary practices. Interventions to reduce TV viewing in this age group may lead to improved diet quality.
PMCID: PMC4249761  PMID: 19086298
Cross-sectional; diet quality; fast food; preschool children; television
3.  Maternal Perception of Neighborhood Safety as a Predictor of Child Weight Status: The Moderating Effect of Gender and Assessment of Potential Mediators 
To determine if there is a relationship between maternal perception of neighborhood safety in 3rd grade and weight status in 5th grade children, to test if gender moderates this relationship, and to identify potential mediators.
Data from 868 children and their mothers involved in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development (NICHD-SECCYD) were used to examine the relationship between maternal perception of neighborhood safety in the 3rd grade and child BMI z-score in the 5th grade. Multiple regression models were used to test this relationship, the effect of gender, and potential mediating variables (time outdoors in neighborhood, television viewing, child behavior problems and puberty status).
Neighborhood safety ratings in the least safe tertile in 3rd grade, compared to the safest tertile, were associated with an increased risk of obesity independent of gender, race and income-to-needs ratio (OR = 1.59; 95% CI 1.03, 2.46), and a higher child BMI z-scores in the 5th grade among girls, but not boys, compared to the safest tertile (β = 0.33; 95% confidence interval, 0.09, 0.57). Neither amount of time spent outdoors in the neighborhood, television viewing, child behavior problems (internalizing or externalizing), nor puberty status altered the relationship.
Maternal perception of the neighborhood as unsafe in 3rd grade independently predicted a higher risk of obesity, and a higher BMI z-score among girls, but not boys, in the 5th grade. The relationship was not explained by several potential mediators. Further investigation is needed to explore these gender differences and potential mediators.
PMCID: PMC4174585  PMID: 19606373
overweight; residence characteristics; neighborhood; safety; physical activity; television; child behavior; puberty
Breastfeeding and infant weight change are both associated with adiposity. We examined the extent to which infant weight change mediates the association between breastfeeding and adiposity at age 3 years.
We studied 884 children in a prospective cohort study. We determined breastfeeding status at 6 months. Our primary outcomes at 3 years were body mass index (BMI) z score and the sum of subscapular and triceps skinfold thicknesses (SS + TR); we also assessed obesity. We defined infant weight change as change in weight-for-age z score between birth and 6 months. We performed multivariable regression analyses.
At age 6 months, 25.0% of infants were fully breastfed. At age 3 years, mean (SD) BMI z score was 0.45 (1.03). In linear regression analyses adjusted for mother’s educational level, race/ethnicity, smoking, BMI, pregnancy weight gain and birth weight (adjusted for gestational age), the BMI z score of fully breastfed children was 0.17 (95% CI:−0.43, 0.09) units lower than never breastfed children. After additional adjustment for infant weight change, the estimate was attenuated (−0.03, 95% CI: −0.27, 0.20). Adjustment for infant weight change only modestly attenuated estimates for SS + TR (from −1.48 (95% CI: −2.52, −0.44) to −1.16 mm (95% CI: −2.18, −0.14)), and for the odds of being obese (from 0.21 (95% CI: 0.07, 0.68) to 0.29 (95% CI: 0.08, 1.05)).
Infant weight change between birth and 6 months mediates associations of breastfeeding with BMI, but only partially with indicators of child adiposity.
PMCID: PMC3977954  PMID: 20979572
body mass index; breastfeeding; infant weight change; obesity; overweight
5.  School-level correlates of physical activity intensity in 10-year old children 
Little is known about school environmental factors that promote or inhibit activity, especially from studies using objective measures in large representative samples. We therefore aimed to study associations between activity intensities and physical and social school environmental factors.
A population-based sample of 1908 British children (SPEEDY study), mean age 10.3 years (SD: 0.3), recruited from 92 schools across Norfolk, UK, with valid activity data (assessed with Actigraph accelerometers). Outcome measures were school-based (8am-4pm on weekdays) time (in minutes) spent in sedentary (<100 counts/min), moderate (2000-3999 counts/min) and vigorous (≥4000 counts/min) activity. A total of 40 school physical and social environmental factors were assessed. Multivariable multilevel linear regression analyses adjusted for children’s sex and body mass index were conducted; interactions with sex were investigated.
Availability of a ‘Park and Stride’ scheme was negatively associated with sedentary minutes (−7.74; 95%CI: −14.8;−0.70). Minutes of moderate activity were associated with the availability of a lollypop person (1.33, 95%CI: 0.35;2.62) and objectively-assessed walking provision (1.70, 95%CI: 0.85;2.56). The number of sports facilities of at least medium quality (0.47, 95%CI: 0.16;0.79), not having a policy on physical activity (−2.28, 95%CI: −3.62;−0.95), and, in boys only, provision of pedestrian training (1.89; 95%CI: 0.77;3.01) were associated with minutes of vigorous activity.
Only a small number of school-level factors were associated with children’s objectively-measured physical activity intensity, giving few pointers for potential future intervention efforts. Further research should focus on using objective measures to elucidate what factors may explain the school-level variance in activity levels.
PMCID: PMC3839262  PMID: 20854106
school; physical activity; behaviour; correlates; physical environment; social environment
6.  Sex dimorphisms in inflammatory markers and adiposity in African American youth 
There are demonstrated sex differences in the association between adiposity and inflammation in adults. Our aim was to determine sex differences in inflammatory markers and in the association between adiposity and inflammation in a sample of African American adolescents.
Adiposity variables including BMI, waist circumference, weight, total fat, trunk fat, and inflammatory markers including IL-6, leptin, MCP1, CRP, adiponectin were examined in 166 (53% female) African American adolescents, ages 14-19 years. Total fat and trunk fat were measured using Dual-Energy X-Ray Absorptiometry (DXA).
Results revealed males had higher weight (p = .01); females had higher BMI, trunk fat, and total fat (p’s < .01). With inflammation, males had higher MCP1 (p = .024); females had higher leptin (p < .001), adiponectin (p = .006), and IL-6 (p = .026). Partial correlations in males indicated associations of adiposity variables with leptin, adiponectin (all p’s < .01), and CRP (p < .05); in females, leptin, CRP, and IL-6 were associated with adiposity variables (all p’s < .05). Multiple regression analyses revealed female adiposity variables predicted CRP, (R2=.254), IL-6 (R2=.167), and MCP1 (R2= .220). Adiposity variables in males predicted lower adiponectin (R2=.245). For both, leptin was predicted by adiposity (males R2=.420 and females R2=.410).
Data indicate clear sex dimorphisms in the associations between inflammatory markers and adiposity in African American adolescents, suggesting that preventive measures and treatments for adolescent obesity may need to be sex-specific.
PMCID: PMC3826793  PMID: 20078375
7.  Patterns of moderate and vigorous physical activity in obese and overweight compared with non-overweight children 
We determined whether overweight and obese children performed less combined moderate and vigorous physical activity (MVPA), less vigorous physical activity (VPA) alone, and had distinct patterns of sustained MVPA or VPA compared with non-overweight children.
We monitored 106 children (aged 8 to 10 years) for 7 consecutive days using accelerometers. Differences in mean daily MVPA and VPA were assessed by comparing non-overweight (NOW) with overweight and obese (OW/OB) participants using descriptive statistics and regression analysis. We used an algorithm to identify periods of consecutive minutes where MVPA or VPA was continuous, called bouts. We then compared the bouts performed by NOW versus OW and OB participants with respect to the mean of the counts·minute−1 for the minutes included in the bout, their mean length in minutes, and the number of MVPA bouts performed in sequence.
The non-overweight group averaged 143 minutes of MVPA per day versus 120 minutes among the OW/OB (p=0.004). The OW/OB group had fewer MVPA bouts per day compared with the NOW (11.6 versus 17.6, p=0.012). Fewer VPA bouts were associated with greater body mass index z-score (p < 0.001). The NOW children had more intense body motion during MVPA bouts and performed a greater proportion of MVPA bouts in sequences of five or more consecutive bouts, compared with the OW/OB (p=0.05 and p=0.002, respectively).
In addition to performing less physical activity, we found that obese and overweight children had distinct patterns of MVPA and VPA bouts compared with non-overweight peers.
PMCID: PMC3815589  PMID: 20883127
Accelerometer; child; obese; physical activity; moderate; vigorous
8.  Dietary self-monitoring and its impact on weight loss in overweight children 
To examine whether dietary self-monitoring is related to weight loss in overweight children and whether perceived social support or dietary self-efficacy affects this relation.
Longitudinal, behavioral intervention study.
The study population included 153 children, aged 7–12 years, with daily food records from a 20-week weight loss program in San Diego, California, USA, conducted between 1999 and 2002.
Self-monitoring was assessed using two methods: a weekly index as a measure of competency (possible range −7 to +35) and recording sufficiency for total compliance (percentage of days).
Significantly greater decreases in percentage overweight were found for children with recording competency at or above the median (mean change: −13.4% vs. −8.6%; p < 0.001) or who were compliant in recording ≥50% of the days (mean change: −13.0% vs. −8.4%; p < 0.001). Using hierarchical linear regression, children who had a higher average weekly monitoring index or recorded sufficiently on more days had significantly greater decreases in percent overweight, after adjusting for age, sex, SES, race/ethnicity and baseline percent overweight (p < 0.001). Perceived social support at baseline and dietary self-efficacy were not related to self-monitoring or change in percent overweight in this sample.
As has been demonstrated with adults and adolescents, self-monitoring in children was associated with greater decreases in percent overweight. However, dietary self-efficacy and perceived social support were not related to how frequently or thoroughly they monitored dietary intake.
PMCID: PMC3788598  PMID: 21722068
9.  Predicting Cardiovascular Risk in Young Adulthood from Metabolic Syndrome, its Component Risk Factors, and a Cluster Score in Childhood 
The value of metabolic syndrome (MetS) in childhood and adolescence and its stability into young adulthood have been questioned. This study compared the MetS in late childhood (mean age 13) versus a cluster score of the MetS components as predictors of young adult (mean age 22) cardiovascular risk.
Anthropometrics, blood pressure, lipid profile, and insulin resistance (insulin clamp) were obtained in 265 individuals at mean ages 13 and 22. MetS was defined dichotomously by current pediatric and adult criteria. The MetS cluster score used the average of deviates of the MetS components standardized to their means and standard deviations at mean age 13.
The MetS was rarely present at mean age 13 and did not predict MetS at mean age 22 but identified individuals who continued to have adverse levels of risk factors at mean age 22. In contrast to the standard MetS definition, the MetS cluster score tracked strongly and at mean age 22 was significantly higher in the individuals with MetS at mean age 13 (0.78 ± 0.71) than those without MetS at mean age 13 (0.09 ± 0.70, p<0.0001).
Although MetS at mean age 13, using the conventional definition, is not a reliable method for predicting MetS at mean age 22, it does predict adverse levels of cardiovascular risk factors. A cluster score, using the MetS components as continuous variables, is more reliable in predicting young adult risk from late childhood.
PMCID: PMC3684392  PMID: 21070100
Metabolic Syndrome; Risk Factors; Obesity; Insulin Resistance; Children
10.  [No title available] 
PMCID: PMC3647369  PMID: 20919806
11.  Fat free mass mediates the association between birth weight and aerobic fitness in youth 
To investigate whether birth weight acts as a biological determinant of later aerobic fitness, and whether fat free mass may mediate this association.
The European Youth Heart Study (EYHS) is a population based cohort of two age groups (10 and 15 years) from Denmark, Portugal, Estonia and Norway. Children with parentally reported birth weight >1.5kg were included (n=2,749). Data was collected on weight, height, and skin fold measures to estimate fat mass and fat free mass. Aerobic fitness (peak power, watts) was assessed using a maximal, progressive cycle ergometer test. Physical activity was collected in a subset (n=1,505) using a hip-worn accelerometer and defined as total activity counts/wear time, all children with >600 minutes/day for ≥3 days of wear were included.
Lower birth weight was associated with lower aerobic fitness, after adjusting for sex, age group, country, sexual maturity and socio-economic status (ß=5.4, 95%CI 3.5, 7.3 W per 1kg increase in birth weight, p<0.001). When fat free mass was introduced as a covariate in the model, the association between birth weight and aerobic fitness was almost completely attenuated (p=0.7). Birth weight was also significantly associated with fat free mass (ß=1.4 95%CI 1.1, 1.8, p<0.001) and fat free mass was significantly associated with aerobic fitness (ß=3.6, 95%CI 3.4, 3.7, p<0.001). Further adjustment for physical activity did not alter the findings.
Birth weight may have long-term influences on fat free mass and differences in fat free mass mediate the observed association between birth weight and aerobic fitness.
PMCID: PMC3574970  PMID: 21050079
12.  A Latent Class Analysis of Psychiatric Symptoms among 125 Adolescents in a Bariatric Surgery Program 
The purpose of this study was to examine whether subgroups could be identified among a sample of adolescents presenting for bariatric surgery.
Participants were 125 severely obese adolescents enrolled in a bariatric surgery program referred for a psychiatric evaluation. A latent class analysis was conducted with self-report and clinician-rated measures of depressive symptoms, total problems by the Youth Self-Report Scale, anxiety severity, eating pathology, psychiatric diagnoses, quality of life, and family functioning.
A 3-class model yielded the best overall fit to the data. Adolescents in the “eating pathology” class demonstrated high levels of both eating disordered and other psychopathology. The second class, or “low psychopathology” class exhibited the fewest psychosocial problems, whereas adolescents in the third class were intermediate on measures of psychopathology, which is consistent with “non-specific psychopathology.”
The latent class analysis identified homogeneous subgroups with different levels of psychopathology among a heterogeneous sample of severely obese adolescents. The identification of clinically relevant subgroups in this study offers an important initial means for examining psychopathology among adolescent bariatric surgery candidates and suggests a number of avenues for future research.
PMCID: PMC3489175  PMID: 21299450
obesity; adolescents; bariatric surgery; psychopathology; latent class analysis
13.  The IWQOL-Kids©: Establishing minimal clinically important difference scores and test-retest reliability 
This study presents additional psychometric testing of the Impact of Weight on Quality of Life-Kids (IWQOL-Kids) with aims to establish distribution-based minimal clinically important difference scores (MCIDs) and evaluate test-retest reliability. Participants (N=263) represent a pooled sample of treatment-seeking obese adolescents (11–19 years) from four large studies examining HRQOL and psychosocial outcomes (MzBMI=2.6± 0.4; Mage=15.1±1.9; 64% female; 51% Black, 46% White). Adolescents completed the IWQOL-Kids©. Standard errors of measurement, which represent the MCID for each scale, were: Physical Comfort=8.8; Body Esteem=7.7; Social Life=8.1; Family Relations=6.2; Total QOL=4.8. Test-retest reliabilities ranged from 0.75–0.88. These data provide further support for the excellent psychometric properties of the IWQOL-Kids. In addition, preliminary MCIDs for IWQOL-Kids scales have now been established, which can be used in clinical trials.
PMCID: PMC3480077  PMID: 20883106
health-related quality of life; psychometrics; weight-specific; adolescents; MCID
14.  Ethnic Variation in Body Composition Assessment in a Sample of Adolescent Girls 
To examine whether bioelectrical impedance analysis (BIA) is a valid measure of body composition in a multiethnic sample of adolescent girls, as compared to dual-energy X-ray absorptiometry (DXA).
Data were from a physical activity intervention study among 276 14–20 year-old sedentary American girls, including 74 whites, 85 blacks, 46 Hispanics, and 71 Asians. Height and weight were objectively measured. Body composition was assessed using a foot-to-foot BIA and a fan-beam DXA. Linear regression models quantified baseline cross-sectional estimates of percent body fat, fat mass, fat-free mass, fat mass index, and fat-free mass index and their BIA-DXA differences, which we considered an estimate of bias. Variation in BIA-DXA by ethnicity and DXA-assessed adiposity was examined with tests of statistical interaction.
Compared to DXA measurement, BIA significantly underestimated percent body fat, fat mass, and fat mass index, and overestimated fat-free mass and fat-free mass index in each ethnic group. There was significant ethnic variation in BIA-DXA bias: percent body fat was underestimated by between 4.8% in blacks and 8.6% in Asians (p-value, interaction<0.001), as were fat mass (p-value=0.012) and fat mass index (p-value<0.001); fat-free mass index was overestimated (p-value=0.002). The degree of ethnic-specific bias varied according to DXA-assessed body composition values. For example, there was relatively greater ethnic variation in bias estimating percent body fat at lower DXA-assessed percent body fat values.
Compared to DXA, BIA underestimated measures of adiposity in a multiethnic adolescent sample. Further, BIA-DXA bias varied by ethnicity and across measures of adiposity.
PMCID: PMC3174327  PMID: 21749194
Bioelectrical impedance; dual-energy X-ray absorptiometry; ethnicity; race adiposity; body composition; female; adolescent
15.  Sleep-disordered breathing in obese adolescents is associated with visceral adiposity and markers of insulin resistance 
Sleep-disordered breathing is associated with obesity, insulin resistance, and the metabolic syndrome in adults. Similar data in children is limited and conflicting. This pilot study examined the relationships between sleep-disordered breathing, visceral adiposity, and cardiometabolic risk factors in obese adolescents. Twenty obese (body mass index ≥95th percentile), otherwise healthy adolescents (age 14.9 ± 2 years) underwent polysomnogram studies, fasting lipid profile and oral glucose tolerance tests, and measures of body composition (dual-energy X-ray absorptiometry) and visceral adiposity (abdominal computed tomography). The severity of sleep-disordered breathing (as measured by apnea-hypopnea index) was positively associated with visceral adipose tissue (r=0.73, p<0.001) but not with other measures of body composition. After controlling for body mass index, the severity of sleep-disordered breathing was positively associated with markers of insulin resistance (homeostasis model assessment and fasting insulin). Further study to allow for critical assessment of the relationships between sleep-disordered breathing and cardiometabolic risk factors in obese youth remains necessary.
PMCID: PMC3428196  PMID: 20545482
Sleep apnea; insulin resistance; central adiposity; abdominal obesity
16.  Socioeconomic differences in obesity among Mexican adolescents 
We investigate socioeconomic disparities in adolescent obesity in Mexico. Three questions are addressed. First, what is the social patterning of obesity among Mexican adolescents? Second, what are the separate and joint associations of maternal and paternal education with adolescent obesity net of household wealth? Third, are there differences in socioeconomic status (SES) gradients among Mexican boys and girls, rural residents and non-rural residents?
Using data from the Mexican National Health Survey 2000 we examined the slope and direction of the association between SES and adolescent obesity. We also estimated models for sub-populations to examine differences in the social gradients in obesity by sex and non-rural residence.
We find that household economic status (asset ownership and housing quality) is positively associated with adolescent obesity. High paternal education is related to lower obesity risk, whereas the association between maternal education and obesity is positive, but not always significant.
The household wealth components of SES appear to predispose Mexican adolescents to higher obesity risk. The effects of parental education are more complex. These findings have important policy implications in Mexico and the United States.
PMCID: PMC3424265  PMID: 20883181
Obesity; socioeconomic status; Mexico; adolescents; parental education
17.  Infant Temperament is Associated with Potentially Obesogenic Diet at 18 Months 
This study investigated whether infants’ temperament at 18 months is associated with the feeding of foods and drinks that may increase the risk for later obesity.
This was a cross-sectional study of mothers and infants (N = 40,266) participating in the Norwegian Mother and Child Cohort Study conducted by the Norwegian Institute of Public Health. Data were collected by questionnaire. Predictor variables were: infants’ temperament at 18 months (internalizing, externalizing, and surgency/extraversion), and mothers’ negative affectivity. Outcomes variables were feeding of sweet foods, sweet drinks, and night-time caloric drinks at 18 months (all dichotomized). Confounders were child’s gender, weight-for-height at 18 months, breastfeeding, and mother’s level of education.
After controlling for confounders, infant temperament dimensions at 18 months were significantly associated with mothers’ feeding of potentially obesogenic foods and drinks independent of mothers’ negative affectivity. Infants who were more internalizing were more likely to be given sweet foods (OR 1.47, CI 1.32–1.65), sweet drinks (OR 1.76, CI 1.56–1.98), and drinks at night (OR 2.91, CI 2.54–3.33); infants who were more externalizing were more likely to be given sweet food (OR 1.53, CI 1.40–1.67) and sweet drinks (OR 1.22, CI 1.11–1.34); and infants who were more surgent were more likely to be given drinks at night (OR1.66, CI 1.42–1.92).
The association between infant temperament and maternal feeding patterns suggests early mechanisms for later obesity that should be investigated in future studies.
PMCID: PMC3128685  PMID: 20854098
infant temperament; sweet foods; sweet drinks; night-time caloric drinks
18.  Efficacy of increasing physical activity to reduce children’s visceral fat: A pilot randomized controlled trial 
To examine whether differentially targeting physical activity within the context of pilot family-based pediatric weight control treatment results in differential change in abdominal fat, particularly visceral fat.
Twenty-nine overweight children (>85th BMI percentile) and at least one participating parent were randomly assigned to one of two family-based behavioral weight management conditions that either targeted 1) primarily dietary change (STANDARD; n=15) or 2) dietary plus physical activity change (ADDED; n=14). Differences at post-treatment in overall child weight status (e.g., BMI), whole-body composition (measured by dual x-ray absorptiometry), and abdominal fat (measured by waist circumference and magnetic resonance imaging) were assessed using intent-to-treat analyses, as were post-treatment parent BMI and weight circumference. Child and parent physical activity and dietary behavior changes were also evaluated.
At post-treatment, overall child weight status, whole-body composition, and child dietary measures did not differ by condition. Children in the ADDED condition tended to have higher physical activity and lower visceral abdominal fat at post-treatment relative to children in the STANDARD condition.
Increasing physical activity may be important to optimize reductions in abdominal fat, especially visceral fat, among overweight children provided family-based behavioral weight management treatment.
PMCID: PMC3010313  PMID: 20528109
pediatric overweight; visceral fat; physical activity; weight management; obesity
19.  Between-slice intervals in quantification of adipose tissue and muscle in children 
Magnetic Resonance Imaging (MRI) is increasingly being used in children to quantify adipose tissue (AT) and skeletal muscle (SM) in vivo. it is unclear whether the every 5 cm whole body MRI protocol used in adults is appropriate when applied in children. Whole body MRI continuous 1 cm thick slices were acquired in 73, aged 5–17-year-old healthy children. images were segmented into subcutaneous (SAT), visceral (VAT), intermuscular At (IMAT), and SM. the percentage difference between volumes measured by the continuous protocol and volumes estimated with protocols of different between-slice intervals (i.e., interval = 2, 3, 4 and 5 cm) was larger with an increase in interval size, depot size, weight and body mass index percentile. For group comparisons, studies will require less than 5.4% more subjects if an every 5 cm protocol is used for equivalent power as the every 1 cm protocol. For individual subject comparisons, interval protocols can be used to reliably distinguish between subjects who differ in SM or SAT volume by 0.14 to 0.64 l (i.e., 1 to 5% of SM or SAT volume) or more, or in VAT or IMAT volume by 0.06 to 0.21 l (i.e., 10 to 30% of VAT or IMAT volume) or more. the every 5 cm image acquisition protocol can be considered as accurate as the contiguous protocol for group comparisons in children, as well as for comparison of SM and SAT among individual children. however, a smaller slice interval protocol would be more accurate for comparison of VAT or IMAT among individual children.
PMCID: PMC3032021  PMID: 20528126
Magnetic resonance imaging; body composition; skeletal muscle; subcutaneous adipose tissue; visceral adipose tissue; intermuscular adipose tissue; measurement error
20.  Socio-demographic disparities in distribution shifts over time in various adiposity measures among American children and adolescents: What changes in prevalence rates could not reveal 
While obesity prevalence in the U.S. has been increasing, adiposity shifts may vary across socio-demographic groups, and various adiposity measures may reveal different patterns.
To study changes over time in adiposity measures, distributional shifts in body mass index (BMI, kg/m2), BMI-percentile, waist circumference (WC) and triceps skinfold thickness (TST), and compare between-group differences, National Health and Nutrition Examination Surveys (NHANES) III 1988-94 and 1999-04 data were analyzed. Annual shift in adiposity measures across percentiles were shown as Tukey's mean-difference plots, with percentile-specific mean differences being divided by 10.5 years. Overall and quintile-specific adjusted shifts were estimated from multivariate ordinary least square (OLS) regression models.
Mean 10.5-year increases in adiposity were statistically significant, higher in older groups, more pronounced in some sex-ethnic groups (e.g. black girls) and at upper percentiles (more obese groups) for most measures and sex-age-ethnic groups. Adjusted increase in mean BMI was 0.60 in girls and 0.64 in boys; BMI percentile, 3.01 and 3.15 units; WC, 2.42 and 2.85 cm; and TST, 0.81 and 1.18 mm. Ethnic, age and sex disparities in mean BMI became wider over time. Several significant ethnic differences in adjusted adiposity shifts within the lowest (Q1) and uppermost (Q5) quintiles of adiposity measure distributions were noted.
The increase in adiposity among American children was unequally distributed across groups and varied across the spectrum of various adiposity measures. Overweight groups gained more adiposity over time, especially WC. Solely examining prevalence shifts masks pattern complexity.
PMCID: PMC3005993  PMID: 20722473
Adiposity; obesity; body mass index; waist circumference; skinfold thickness; child; adolescent; United States
21.  For whom and under what circumstances do school-based energy balance behavior interventions work? Systematic review on moderators 
The aim of this review was to systematically review the results and quality of studies investigating the moderators of school-based interventions aimed at energy balance-related behaviors. We systematically searched the electronic databases of Pubmed, EMBASE, Cochrane, PsycInfo, ERIC and Sportdiscus. In total 61 articles were included. Gender, ethnicity, age, baseline values of outcomes, initial weight status and socioeconomic status were the most frequently studied potential moderators. The moderator with the most convincing evidence was gender. School-based interventions appear to work better for girls than for boys. Due to the inconsistent results, many studies reporting non-significant moderating effects, and the moderate methodological quality of most studies, no further consistent results were found. Consequently, there is lack of insight into what interventions work for whom. Future studies should apply stronger methodology to test moderating effects of important potential target group segmentations.
PMCID: PMC3190836  PMID: 21651421
Children; diet; intervention; moderator; overweight; physical activity
22.  Obesity and depressed mood associations differ by race/ethnicity in adolescent girls 
To evaluate bidirectional associations between obesity and depressed mood in adolescent girls, and assess whether these associations differed by racial/ethnic group.
We analyzed data collected from 918 adolescent girls studied in 6th and 8th grades as part of the Trial of Activity for Adolescent Girls (TAAG). Racial/ethnic group was defined as non-Hispanic white, non-Hispanic black, and Hispanic. Height and weight were measured and obesity was defined as a BMI-for-age at or above the 95th percentile. The Center for Epidemiologic Studies Depression Scale (CES-D) was used to measure depressive symptoms. Generalized estimating equations were used to examine associations between 6th grade obesity and 8th grade depressed mood, as well as 6th grade depressed mood and 8th grade obesity.
Racial/ethnic group was a statistically significant effect modifier in both directions of association (p < 0.02). Among white girls, 6th grade obesity was associated with greater likelihood of depressed mood in 8th grade (odds ratio (OR) = 2.47, 95% confidence interval (CI): 1.85, 3.30); for black and Hispanic girls OR= 1.16 and 0.82, respectively. Also for white girls, 6th grade depressed mood was associated with greater likelihood of obesity in 8th grade (OR = 4.47, CI: 1.96, 10.24); whereas for black and Hispanic girls OR= 0.83 and 1.89, respectively.
These analyses suggest that associations between obesity and depressed mood may be most problematic among adolescent girls in the white racial/ethnic group, and our results are consistent both with depressed mood contributing to obesity and obesity contributing to depressed mood.
PMCID: PMC3066285  PMID: 20367561
adolescents; depression; epidemiology; ethnic minorities; obesity; prospective study
23.  Psychosocial and Familial Impairment Among Overweight Youth with Social Problems 
Emerging research indicates that overweight children with social impairments are less responsive to weight control interventions over the long term. A better understanding of the breadth and psychosocial correlates of social problems among overweight youth is needed to optimize long-term weight outcomes.
A total of 201 overweight children, aged 7–12 years, participated in a randomized controlled trial of two weight maintenance interventions following family-based behavioral weight loss treatment. Children with HIGH (T≥65) versus LOW (T<65) scores on the Child Behavior Checklist Social Problems subscale were compared on their own and their parents’ pre-treatment levels of psychosocial impairment using multivariate analysis of variance. Hierarchical regression was used to identify parent and child predictors of social problems in the overall sample.
HIGH (n=71) children evidenced greater eating disorder psychopathology and lower self-worth, as well as a range of interpersonal difficulties, compared to LOW children (n=130; ps<.05). Compared to parents of LOW children, parents of HIGH children reported greater levels of their own general psychopathology (p<.05). Parent psychopathology significantly added to the prediction of social problems in the full sample beyond child sex and z-BMI (ps<.01).
A substantial minority of overweight youth experience deficits across the social domain, and such deficits appear to be associated with impairment in a broad range of other psychosocial domains. Augmenting weight loss interventions with specialized treatment components to address child and parent psychosocial problems could enhance socially-impaired children’s long-term weight outcomes and decrease risk for later development of psychiatric disturbances.
PMCID: PMC3082286  PMID: 20233153
Childhood obesity; social problems; psychopathology; eating disorders; teasing
24.  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. No systematic studies of the effects of LGL diets have been conducted in obese US Hispanic children even though Hispanic children have a particularly high prevalence of obesity and thus stand to benefit from successful interventions.
To examine the effects of LGL and high-GL (HGL) meals on appetitive responses and ad libitum energy intake of obese Hispanic youth.
88 obese Hispanic youth ages 7-15y were randomly assigned to consume meals designed to be either LGL (n=45) or HGL (n=43). Following the morning test meal, subjects serially reported hunger, fullness, and satiety using a visual analog scale and provided samples for analysis of serum insulin and plasma glucose. Participants were then fed another test meal and given a snack platter from which to eat ad libitum. Energy, macronutrients, and glycemic load (GL) of consumed foods were calculated for each meal.
Subjects in the HGL group had significantly higher insulin (p=0.0005) and glucose (p=0.0001) responses to the breakfast meal compared to the LGL group. However, there were no significant between-group differences in the total 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.
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.
PMCID: PMC3128645  PMID: 21309658
obese; Hispanic youth; glycemic load; food intake; hunger; satiety; fullness
25.  Increased Oxidative Stress and Altered Substrate Metabolism in Obese Children 
Pediatric obesity, a major risk factor for cardiovascular diseases and diabetes, has steadily increased in the last decades. Although excessive inflammation and oxidation are possible biochemical links between obesity and cardiovascular events in adults, little information is available in children. Furthermore, effects of gender and fitness on the interaction between dyslipidemia and oxidative or inflammatory stress in children are mostly unknown. Therefore, we measured systemic markers of oxidation (F2-isoprostanes, F2-IsoP, and antioxidants) and inflammation (interleukin-6, IL-6, and leukocyte counts) and metabolic variables in 113 peripubertal children (55 obese, Ob, age and gender-adjusted BMI%≥95th, 25F; 15 overweight, OW, BMI% 85th–95th, 8F; 43 normoweight, CL, 25F). Overall, when compared to CL, Ob displayed elevated F2-IsoP (99±7 vs. 75±4 pg/mL, p<0.005), IL-6 (2.2±0.2 vs. 1.5±0.3 pg/mL, p<0.005), elevated total WBC and neutrophils, and altered levels of total cholesterol, LDL-C, HDL-C, triglycerides, free fatty acids, glucose, and insulin (all p<0.005). This pattern was independent of gender and not caused by reduced fitness in Ob. Our data indicate that alterations in metabolic control and a concomitant increase in inflammation and oxidative stress occur early in life in obese children, likely exposing both genders to a similar degree of increased risk of future cardiovascular diseases.
PMCID: PMC3110748  PMID: 20233149
dyslipidemia; inflammation; oxidative stress; childhood obesity

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