The thermoneutral zone in women takes an "arctic" shift compared to men.

Conventionally, women are perceived to feel colder than men, but controlled comparisons are sparse. We measured the response of healthy, lean, young women and men to a range of ambient temperatures typical of the daily environment (17 to 31 °C). The Scholander model of thermoregulation defines the lower critical temperature as threshold of the thermoneutral zone, below which additional heat production is required to defend core body temperature. This parameter can be used to characterize the thermoregulatory phenotypes of endotherms on a spectrum from "arctic" to "tropical." We found that women had a cooler lower critical temperature (mean ± SD: 21.9 ± 1.3 °C vs. 22.9 ± 1.2 °C, P = 0.047), resembling an "arctic" shift compared to men. The more arctic profile of women was predominantly driven by higher insulation associated with more body fat compared to men, countering the lower basal metabolic rate associated with their smaller body size, which typically favors a "tropical" shift. We did not detect sex-based differences in secondary measures of thermoregulation including brown adipose tissue glucose uptake, muscle electrical activity, skin temperatures, cold-induced thermogenesis, or self-reported thermal comfort. In conclusion, the principal contributors to individual differences in human thermoregulation are physical attributes, including body size and composition, which may be partly mediated by sex.

Retrieval-induced forgetting in children and adolescents with and without obesity.

BACKGROUND/OBJECTIVES: Previous research indicates that youth with obesity exhibit deficits in executive functioning (EF), which often take the form of impaired response inhibition. One aspect of EF not previously studied in obesity is the adaptive process known as retrieval-induced forgetting (RIF), the suppression/inhibition of intrusive or non-target items by the retrieval of specific items from memory. The present study investigated if child or adolescent obesity disrupts the ability to inhibit retrieval of intrusive memories. SUBJECTS/METHODS: We compared the manifestation of RIF in children (ages 8-12) and adolescents (ages 13-18) as a function of their weight status and sex. We also evaluated the effects of these variables on simple recall of items from episodic memory under conditions where competition from intrusive items was reduced. RESULTS: Children with obesity did not demonstrate significant RIF, whereas RIF was exhibited by preteens without obesity and by teenage participants with- and without obesity (Weight Status × Age Group interaction p = 0.028). This pattern of results did not differ as a function of sex for either age group. No differences in episodic memory were found. Additional analyses using Age as continuous covariate (and not as a nominal group) comparing participants who exhibited RIF with those who did not, found that the no RIF group consumed fast-food meals more frequently (p = 0.024) and had higher percentages of total body adiposity and android fat compared to the RIF group (p's < 0.05). CONCLUSIONS: The findings expand what is known about the effects of childhood obesity on cognitive functioning, identify impaired RIF with specific behavioral and dietary factors and increased adiposity, and suggest the possibility that impairments in the ability to inhibit intrusive memories of food and eating may contribute to poor early-life weight control.

Effects of interrupting daily sedentary behavior on children's glucose metabolism: A 6-day randomized controlled trial.

BACKGROUND: Metabolic disease risk in youth is influenced by sedentary behaviors. Acute in-lab studies show that, during a single day, interrupting a sedentary period with short bouts of physical activity improves glucometabolic outcomes. OBJECTIVE: To determine if acutely improved glucose metabolism persists after multi-day interruptions of sitting with walking brief bouts. We hypothesized that children who underwent interrupting sitting on multiple days would demonstrate lower insulin area under the curve during an oral glucose tolerance test compared to uninterrupted sitting. METHODS: Healthy, normoglycemic children (N = 109) ages 7-11 years were randomized to one of two conditions: Control (3 h of daily Uninterrupted Sitting) or Interrupted Sitting (3-min of moderate-intensity walking every 30 min for 3 h daily); with dietary intake controlled through provision of foodstuffs for the entire experiment. Participants attended six consecutive daily visits at a research ambulatory unit. The primary outcome was insulin area under the curve during the oral glucose tolerance test on day 6 during interrupted or uninterrupted sitting; secondary outcomes included glucose and c-peptide area under the curve, energy intake at a buffet meal on day 6, and free-living activity. RESULTS: Among 93 children (42 uninterrupted sitting, 51 interrupted sitting), daily interrupted sitting resulted in 21% lower insulin (ß = 0.102 CI:0.032-0.172, p = 0.005) and a 10% lower C-peptide (ß = 0.043, CI:0.001-0.084, p = 0.045) area under the curve. Matsuda and Glucose Effectiveness Indices were also improved (p's < 0.05). There were no group differences in energy intake or expenditure. CONCLUSIONS: Sustained behavioral change by interrupting sedentary behaviors is a promising intervention strategy for improving metabolic risk in children.

Bridging executive function and disinhibited eating among youth: A network analysis.

OBJECTIVE: Poorer executive function (EF) has been linked to disinhibited eating in youth, suggesting poor EF predisposes toward obesity, yet the specific nature and extent of interconnections between facets of these domains is unclear. Network analysis provides a promising framework for elucidating the relationship between poor EF and disinhibited eating, and offers insights into potential maintenance processes. METHOD: Among youth ages 8-17 years, a regularized partial correlation network of EF and disinhibited eating facets was estimated to examine expected influence centrality and bridge expected influence. Computerized neurocognitive tasks assessed EF variables, including decision-making, general and food-related inhibitory control, delayed gratification, cognitive flexibility, and working memory. Disinhibited eating variables included total carbohydrate-fat intake at a laboratory test meal and self-reported eating in the absence of hunger, emotional eating, and loss-of-control eating severity. RESULTS: In the current sample (N = 248; Mage = 12.5; 54.8% female; 43.5% non-Hispanic White; 25.8% non-Hispanic Black; BMI %ile = 65.8 ± 27.8), emotional eating in response to depressive symptoms emerged as a central symptom in the network. Carbohydrate-fat intake had the highest bridge expected influence and was most strongly connected to general inhibitory control (part r = .14). DISCUSSION: The link between general inhibitory control and objective palatable food intake may be particularly salient in maintaining maladaptive eating behavior. Interventions targeting behavioral disinhibition may disrupt associations among a network of disinhibited eating facets in youth and should be targets for longitudinal research.

Food cravings and loss-of-control eating in youth: Associations with gonadal hormone concentrations.

OBJECTIVE: Among youth with overweight, food cravings (FC) are associated with loss-of-control (LOC)-eating, but the impact of sex-associated biological characteristics on this relationship is unknown. We examined whether sex and gonadal hormone concentrations moderated the relationships between FC and LOC-eating severity among healthy boys and girls across the weight strata in natural and laboratory environments. METHOD: Using ecological momentary assessment (EMA), FC, and LOC-eating severity were reported 3-5 times a day for 2 weeks. In the laboratory, participants reported FC, consumed lunch from a buffet test meal designed to simulate LOC-eating, and rated LOC-eating severity during the meal. RESULTS: Eighty-seven youth (13.0 ± 2.7 years, 58.6% female, 32.2% with overweight/obesity) participated. EMA measured general and momentary FC were positively associated with LOC-eating severity (ps < .01), with no differences by sex (ps = .21-.93). Estradiol and progesterone significantly moderated the relationships between FC and LOC-eating such that general FC and LOC-eating severity were only positively associated among girls with greater (vs. lower) estradiol (p = .01), and momentary FC and LOC-eating severity were only positively associated among girls with greater (vs. lower) progesterone (p = .01). Boys' testosterone did not significantly moderate the associations between FC and LOC-eating severity (ps = .36-.97). At the test meal, pre-meal FC were positively related to LOC-eating severity (p < .01), without sex or hormonal moderation (ps = .20-.64). DISCUSSION: FC were related to LOC-eating severity in boys and girls. In the natural environment, gonadal hormones moderated this relationship in girls, but not boys. The mechanisms through which gonadal hormones might affect the relationship between FC and LOC-eating warrant investigation.

Inhibitory control and negative affect in relation to food intake among youth.

Negative affect and poor inhibitory control are related to disinhibited eating behaviors in youth and may contribute to the development and/or maintenance of obesity. Although few studies have jointly examined these constructs in youth, it has been theorized that poor inhibitory control may be driven by negative affect. If supported, impaired inhibitory control, driven by negative affect, could represent a modifiable neurocognitive treatment target for disinhibited eating. The current study examined whether inhibitory control mediates the relationship between negative affect and eating among youth. Youth (8-17 years) participated in a Food Go/No-Go neurocognitive task to measure inhibitory control as the percentage of commission errors. A composite negative affect score was created from self-report measures of anxiety and depression. A laboratory buffet meal modeled to simulate disinhibited eating was used to measure total and snack food intake. Cross-sectional mediation models with bias-corrected bootstrap confidence intervals (CI) were conducted using negative affect as the independent variable, inhibitory control as the mediator, and intake patterns as dependent variables. One-hundred-eighty-one youths (13.2 ± 2.7y; 55% female; BMIz 0.6 ± 1.0) were studied. Total Go/No-Go commission errors mediated the relationship between negative affect and total intake (95%CI = [0.3, 31.6]), but not snack intake (95%CI = [-2.5, 7.3]). Commission errors for Food-Go blocks significantly mediated the relationship between negative affect and total intake (95%CI = [7.7, 44.4]), but not snack intake (95%CI = [-3.4, 9.5]). Commission errors on Neutral-Go blocks did not significantly mediate any of these relationships. Negative affect may lead to poorer inhibitory control as well as a stronger approach tendency toward food, increasing the likelihood of engaging in disinhibited eating. Future research should determine if, in combination with approaches to reduce negative affect, improved inhibitory control could help prevent overeating in youths with depressive or anxiety symptoms.

The association between alexithymia and eating behavior in children and adolescents.

OBJECTIVE: Alexithymia, or the difficulty identifying or describing one's own emotions, may be a risk factor for dysregulated eating and excess weight gain. However, the relationships between alexithymia and eating behaviors in community samples of non-clinical youth have not been well-characterized. We hypothesized that alexithymia would be positively associated with disordered and disinhibited eating in a community-based sample of boys and girls without an eating disorder. METHOD: Two hundred children (8-17 years old) across the weight spectrum completed an interview to assess loss of control (LOC) eating and eating-related psychopathology, a laboratory test meal designed to induce disinhibited eating, and questionnaires to assess alexithymia, eating in the absence of hunger, and emotional eating. Linear and logistic regressions were conducted to examine the relationship between alexithymia and eating variables, with age, sex, race, and fat mass as covariates. Test meal analyses also adjusted for lean mass. Given the overlap between alexithymia and depression, all models were repeated with depressive symptoms as an additional covariate. RESULTS: Alexithymia was associated with an increased likelihood of reporting LOC eating (p < .05). Moreover, alexithymia was positively associated with disordered eating attitudes, emotional eating, and eating in the absence of hunger (ps < .05). Greater alexithymia was associated with more carbohydrate and less fat intake at the test meal (ps < .05). After adjusting for depressive symptoms, alexithymia remained associated with eating in the absence of hunger and carbohydrate and fat intake (ps < .05). DISCUSSION: In healthy children, alexithymia is associated with some facets of eating behavior and food intake. If supported prospectively, these preliminary findings suggest alexithymia may be a modifiable risk factor to reduce disordered eating and excess weight gain in youth.

An open-label 16-week study of liraglutide in adolescents with obesity post-sleeve gastrectomy.

BACKGROUND: Up to 50% of adolescents who undergo metabolic and bariatric surgery (MBS) have obesity 3 years post-MBS, placing them at continued risk for the consequences of obesity. OBJECTIVES: We conducted an open-label, 16-week pilot study of liraglutide in adolescents with obesity after sleeve gastrectomy (SG) to investigate liraglutide effects on weight and body mass index (BMI) post-SG. METHODS: Adolescents aged 12-20.99 years with obesity and a history of SG ≥1 year prior were enrolled. Liraglutide was initiated at 0.6 mg/day, escalated weekly to a maximum of 3 mg/day, with treatment duration 16 weeks. Fasting laboratory assessments and an oral glucose tolerance test were performed at baseline and end-treatment. RESULTS: A total of 43 participants were screened, 34 initiated liraglutide (baseline BMI 41.2 ± 7.7 kg/m2), and 31 (91%) attended the end-treatment visit. BMI decreased by 4.3% (p < 0.001) with liraglutide. Adolescents who had poor initial response to SG (<20% BMI reduction at BMI nadir) had less weight loss with liraglutide. Fasting glucose and haemoglobin A1C concentrations significantly decreased. There were no serious treatment-emergent adverse events reported. CONCLUSIONS: Liraglutide treatment was feasible and associated with a BMI reduction of 4.3% in adolescents who had previously undergone SG, quantitatively similar to results obtained in adolescents with obesity who have not undergone MBS.

A Pilot Randomized Control Trial Testing a Smartphone-Delivered Food Attention Retraining Program in Adolescent Girls with Overweight or Obesity.

BACKGROUND/OBJECTIVES: Attention bias (AB) toward food is associated with obesity, but it is unclear if programs designed to reduce AB can impact adolescents' eating behavior. We investigated whether a two-week, smartphone-delivered attention retraining (AR) program (vs a control program) altered food AB in adolescent girls with overweight. METHODS: Participants completed three food-cue visual-probe trainings/day. The AR and control programs directed attention away from food stimuli during 100% and 50% of trainings, respectively. Before and after completion of the programs, girls completed a food-cue visual-probe task while undergoing magnetoencephalography (MEG), and then a laboratory test meal. RESULTS: Sixty-eight adolescents were randomized; 58 completed post-program visits. There was minimal effect of condition on AB scores (ß [95%CI] = -1.9 [-20.8, 16.9]; d = -0.06). There was a small effect of condition on energy intake (EMMcontrol = 1017 kcal, EMMAR = 1088 kcal, d = 0.29). Within the AR group, there was slightly blunted initial engagement in brain areas associated with reward response and subsequent increased goal-directed attention and action control. CONCLUSIONS: We found preliminary support for efficacy of an intensive smartphone-delivered AR program to alter neural correlates of attention processing in adolescent girls with overweight or obesity. Studies with larger sample sizes are needed to elucidate if AR trainings disrupt the link between food AB and eating behavior.

Youth's energy intake during a laboratory-based loss-of-control eating paradigm: Associations with reported current dieting.

Dieting is theorized as a risk factor for loss-of-control (LOC)-eating (i.e., feeling a sense of lack of control while eating). Support for this association has largely relied on retrospective self-report data, which does not always correlate with objectively assessed eating behavior in youth. We hypothesized that during a laboratory-based LOC-eating paradigm, children and adolescents who reported current (at the time of the visit) dieting would consume meals consistent with LOC-eating (greater caloric intake, and intake of carbohydrates and fats, but less intake of protein). Participants were presented with a buffet-style meal and instructed to "Let yourself go and eat as much as you want." Current dieting (i.e., any deliberate change to the amount or type of food eaten to influence shape or weight, regardless of how effective the changes are) was assessed via interview. General linear models were adjusted for fat mass (%), lean mass (kg), height, sex, protocol, race and ethnicity, pre-meal hunger and minutes since consumption of a breakfast shake. Of 337 participants (Mage 12.8 ± 2.7y; 62.3 % female; 45.7 % non- Hispanic White and 26.1 % non-Hispanic Black; MBMIz 0.78 ± 1.11), only 33 (9.8 %) reported current dieting. Current dieting was not significantly associated with total energy intake (F = 1.63, p = .20, ηp2 = 0.005), or intake from carbohydrates (F = 2.45, p = .12, ηp2 = 0.007), fat (F = 2.65, p = .10, ηp2 = 0.008), or protein (F = 0.39, p = .53, ηp2 = 0.001). Contrary to theories that dieting promotes LOC-eating, current dieting was not associated with youth's eating behavior in a laboratory setting. Experimental approaches for investigating dieting are needed to test theories that implicate dieting in pediatric LOC-eating.

Changes in Food Consumption, BMI, and Body Composition in Youth in the US during the COVID-19 Pandemic.

Rates of childhood overweight/obesity have risen for decades; however, data show the prevalence increased at a faster rate during the COVID-19 pandemic. Pandemic-associated increases in youth's body mass index (BMI; kg/m2) have been attributed to decreases in reported physical activity; few studies have examined changes in food intake. We therefore examined changes in total energy, nutrient consumption, BMI, BMIz, and adiposity longitudinally over 3 years, comparing healthy youth aged 8-17 years assessed twice prior to the pandemic, to youth seen once before and once during the pandemic. The total energy intake and percent macronutrient consumption were assessed using a standardized, laboratory-based, buffet-style meal. Height and weight were measured and adiposity was collected via dual energy X-ray absorptiometry. Generalized linear model univariate analyses investigated differences between groups. One-hundred-fifteen youth (15.6 + 2.8 years 47.8% female; 54.8% White) from the Washington D.C., Maryland, and Virginia greater metropolitan area participated. In this secondary analysis, neither changes in total energy intake (p = 0.52) nor changes in nutrient consumption were significantly different between the two groups (ps = 0.23-0.83). Likewise, changes in BMI, BMIz, and adiposity (ps = 0.95-0.25) did not differ by group. Further research should investigate food intake and body composition, comparing youth with and without overweight/obesity to better identify those at greatest risk of excess weight gain during the pandemic.

Neural underpinnings of threat bias in relation to loss-of-control eating behaviors among adolescent girls with high weight.

Introduction: Loss-of-control (LOC) eating, a key feature of binge-eating disorder, may relate attentional bias (AB) to highly salient interpersonal stimuli. The current pilot study used magnetoencephalography (MEG) to explore neural features of AB to socially threatening cues in adolescent girls with and without LOC-eating. Methods: Girls (12-17 years old) with overweight or obesity (BMI >85th percentile) completed an AB measure on an affective dot-probe AB task during MEG and evoked neural responses to angry or happy (vs. neutral) face cues were captured. A laboratory test meal paradigm measured energy intake and macronutrient consumption patterns. Results: Girls (N = 34; Mage = 15.5 ± 1.5 years; BMI-z = 1.7 ± 0.4) showed a blunted evoked response to the presentation of angry face compared with neutral face cues in the left dorsolateral prefrontal cortex, a neural region implicated in executive control and regulation processes, during attention deployment (p < 0.01). Compared with those without LOC-eating (N = 21), girls with LOC-eating (N = 13) demonstrated a stronger evoked response to angry faces in the visual cortex during attention deployment (p < 0.001). Visual and cognitive control ROIs had trends suggesting interaction with test meal intake patterns among girls with LOC-eating (ps = 0.01). Discussion: These findings suggest that girls with overweight or obesity may fail to adaptively engage neural regions implicated in higher-order executive processes. This difficulty may relate to disinhibited eating patterns that could lead to excess weight gain.

Associated features of pediatric loss-of-control eating severity during a laboratory-based feeding paradigm.

Laboratory-based loss-of-control eating (LOC-eating; i.e., feeling like one cannot stop eating) paradigms have provided inconsistent evidence that the features of pediatric LOC-eating are consistent with those of DSM-5-TR binge-eating episodes. Thus, this study investigated whether recent LOC-eating (in the prior month) and/or greater LOC-eating severity during a meal are positively associated with faster eating rate, energy intake when adjusting for hunger, post-meal stomachache and sickness (a proxy for eating until uncomfortably full), depression, and guilt. Recent LOC-eating was assessed via interview. Participants were presented with a buffet-type meal and instructed to "Let yourself go and eat as much as you want." Immediately following, youth reported on their experience of LOC-eating during the meal (LOC-eating severity). Eating rate (kcal/min) was computed by dividing total energy intake by the duration of the meal. Prior to and following the meal, youth reported hunger, sickness, and stomachache via sliding Visual Analog Scales, depression via the Brunel Mood Scale and guilt via the PANAS-X. Three-hundred-ten youth participated (61.2 % Female; 46.3 % non-Hispanic White, 12.96 ± 2.72 y). Recent LOC-eating was not significantly associated with any DSM-5-TR binge-eating feature during the laboratory meal (ps = 0.07-0.85). However, LOC-eating severity during the meal was positively associated with eating rate, eating adjusted for hunger, post-meal sickness and stomachache, and guilt (ps < 0.045). LOC-eating severity during a laboratory-based feeding paradigm meal, but not recent LOC-eating, was associated with several features of DSM-5-TR binge-eating episodes. Future studies should assess multiple components of LOC-eating to further characterize the phenomenology of pediatric LOC-eating.

Associations of food reinforcement and food- related inhibitory control with adiposity and weight gain in children and adolescents.

Some, but not all studies have reported that, among youth with disordered eating and high weight, the relative reinforcing value of food (RRV-F, i.e., how hard a person will work for a high-energy-dense food when another reward is available) is greater, and food-related inhibitory control (i.e., ability to withhold a response to food-related stimuli) is lower, compared to peers without disordered eating or overweight. In most studies, high RRV-F and low food-related inhibitory control have been studied separately, as independent factors, with each suggested to predict excess weight and adiposity (fat mass) gain. We hypothesized that the interaction of these factors would prospectively exacerbate risk for weight and adiposity (fat mass) gain three years later in a sample of healthy youth. At baseline, RRV-F was measured using a Behavior Choice Task with the rewards being standardized servings of chocolate candies, cheese crackers, or fruit snacks. Food-related inhibitory control was determined by performance in response to food and non-food stimuli during a Food Go/No-Go task. At baseline and 3-year visits, total body adiposity was measured by dual-energy X-ray absorptiometry (DXA) and body mass index (BMI) was obtained using measured weight and height. A linear regression was conducted with 3-year adiposity as the dependent variable. RRV-F, food-related inhibitory control, and the RRV-F x food-related inhibitory control interaction as independent variables. Baseline adiposity, age, height, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year adiposity. Baseline BMI, age, sex, race/ethnicity, and days between visits were included as covariates for model predicting 3-year BMI. One-hundred and nine youth (mean 12.4±2.7y, mean 0.50±1.02 BMIz, 30.3% with overweight/obesity, 45.9% female, 51.4% non-Hispanic White), 8-17 years at baseline, were studied. Baseline food-related inhibitory control (ßunstandardized = 0.33, p = .037, 95% CI [.02, 0.64]), but not baseline RRV-F (ßunstandardized = -0.003, p = .914), 95% CI [-0.05, 0.05]) was significantly associated with 3-year adiposity such that those with the poorest food-related inhibitory control (great number of commision errors) had the greatest adiposity gain. The interaction between RRV-F and food-related inhibitory control did not predict 3-year adiposity (ßunstandardized = -0.07, p = .648, 95% CI [-0.39, 0.25]). The pattern of findings was the same for models examining non-food related inhibitory control. Neither baseline food-related inhibitory control (ßunstandardized = 2.16, p = .256, 95% CI [-1.59, 5.92]), baseline RRV-F (ßunstandardized = 0.14, p = .660, 95% CI [-0.48, 0.75]), nor their interaction (ßunstandardized = -1.18, p = .547, 95% CI [-5.04, 2.69]) were significantly associated with 3-year BMI. However, non-food related inhibitory control (ßunstandardized = 0.54, p = .038, 95% CI [.22, 7.15]) was significantly associated with 3-year BMI. In summary, food-related inhibitory control but not RRV-F, was associated with changes in adiposity in a sample of children and adolescents. Among generally healthy youth, food-related inhibitory control may be a more relevant risk factor than food reinforcement for adiposity gain. Additional data are needed to determine how inhibitory control and reward systems, as well as other disinhibited eating behaviors/traits, may interact to promote excess weight gain over time in youth.

Heart Rate Variability and Laboratory-Based Loss-of-Control Eating in Children and Adolescents.

Among youth, greater heart rate (HR) and lesser HR variability (HRV) are precursors to loss-of-control (LOC) eating episodes in the natural environment. However, there are limited data examining whether pre-meal HR and HRV are associated with greater LOC-eating in the laboratory setting. We therefore examined temporal relationships between pre-meal HR, frequency- and time-based metrics of pre-meal HRV, perceived LOC-eating, and energy intake during a meal designed to simulate a LOC-eating episode. Among 209 participants (54.5% female, 12.58 ± 2.72 years, 0.52 ± 1.02 BMIz), 19 reported LOC-eating in the prior month. Perceived LOC-eating during the laboratory meal was not significantly linked to pre-meal HR (p = 0.37), but was positively related to pre-meal HRV (ps = 0.02-0.04). This finding was driven by youth with recent LOC-eating, as these associations were not significant when analyses were run only among participants without recent reported LOC-eating (p = 0.15-0.99). Pre-meal HR and HRV were not significantly related to total energy intake (ps = 0.27-0.81). Additional research is required to determine whether early-stage pediatric LOC-eating is preceded by a healthy pre-meal stress response. Longitudinal studies could help clarify whether this pattern becomes less functional over time among youth who develop recurrent LOC-eating episodes.

Longitudinal associations between facets of sleep and adiposity in youth.

OBJECTIVE: Beyond sleep duration, other facets of sleep such as variability and timing may be associated with obesity risk in youth. However, data are limited. Using a longitudinal design, this study tested whether multiple facets of sleep were associated with fat mass gain over 1 year. METHODS: A convenience sample of non-treatment-seeking youth (age 8-17 years) wore actigraphy monitors for 14 days. Average weekly sleep duration, within-person sleep duration variability, weekend catch-up sleep, bedtime and wake time shift, social jet lag, bedtime, wake time, and sleep midpoint were calculated. The association of each facet of baseline sleep with 1-year fat mass, adjusting for baseline fat mass and height, was examined. RESULTS: A total of 137 youths (54.0% female; mean [SD], age 12.5 [2.6] years; 28.4% non-Hispanic Black or African American; baseline fat mass = 15.3 [8.9] kg; 1-year fat mass = 17.0 [10.0] kg; 28.5% with baseline overweight or obesity) were studied. Wake time (p = 0.03) and sleep midpoint (p = 0.02) were inversely associated with 1-year fat mass, such that earlier wake time and midpoint were associated with higher 1-year fat mass. No other facet of sleep was significantly associated with 1-year fat mass (p > 0.09). CONCLUSIONS: Using objective measures, youth with earlier wake times and sleep midpoints had greater gains in fat mass. Additional research is needed to determine whether sleep timing may be a modifiable target to prevent pediatric obesity.

Body adiposity measured by bioelectrical impedance is an alternative to dual-energy x-ray absorptiometry in black Africans: The Africans in America Study.

OBJECTIVES: The prevalence of cardiometabolic disease has risen in Africa and parallels the obesity epidemic. To assess cardiometabolic risk, body composition measurements by dual-energy X-ray absorptiometry (DXA) are ideal. In communities with limited resources, alternative measures may be useful but have not been compared extensively in black Africans. Therefore, the aim of this study was to identify alternative methods of body composition assessment, such as body adiposity index (BAI) and bioelectrical impedance analysis (BIA), for use in African-born blacks. METHODS: This was a cross-sectional study with African-born blacks. BAI and five BIA predictive equations (using variations of height, weight, age, sex, and impedance) were compared with DXA to estimate percent fat. Participants were 266 African-born blacks (39 ± 10 y, body mass index 28 ± 4 kg/m2, and 68% men) living in metropolitan Washington DC. Equivalence (90% confidence interval, -3 to 3), concordance, and Bland-Altman analyses (bias <2%, R2 closest to zero) compared BAI or BIA predictive equations to DXA as the criterion method. RESULTS: DXA percent fat was 27.2% ± 5.5% and 40.3% ± 6.9% in men and women, respectively. BAI underestimated percent fat in men (bias: 1.88 ± 4.71, R2 = 0.25, P < 0.001) and women (bias: 6.47 ± 4.94, R2 = 0.08, P = 0.01). Of the five BIA predictive equations, the equation reported by Sun et al. had the best agreement with DXA percent fat for men (bias: -0.91 ± 3.67, R2 = 0.02, P = 0.05) and women (bias: -0.92 ± 4.02, R2 = 0.003, P = 0.58). Percent fat from the Sun et al. equation best agreed with DXA percent fat. CONCLUSION: BIA with the Sun et al. predictive equation was the best alternative to DXA for body fat assessment in African-born blacks.

Executive functioning and disinhibited eating in children and adolescents.

BACKGROUND: Executive functioning (EF) difficulties may be associated with problems regulating eating behaviours. Few studies have evaluated this question in youth using diverse measures of EF or objective measures of energy intake. METHODS: The current study used neuropsychological tasks and a laboratory test meal to evaluate the links between EF and youth's disinhibited eating patterns. Two-hundred-five nontreatment seeking youth (M age = 13.1 ± 2.8 years; M BMIz = 0.6 ± 1.0; 33.2% overweight; 54.1% female) completed tasks measuring decision making, general and food-specific behavioural disinhibition, willingness to delay gratification for food and money, cognitive flexibility, and working memory. Age (children vs adolescents) was examined as a moderator. All analyses adjusted for demographic factors, pubertal status, lean mass (kg), fat mass (%), height, general intellectual functioning, and depressive symptoms. RESULTS: After adjusting for multiple comparisons, more general behavioural disinhibition was associated with greater total energy intake (P = .02), and poorer cognitive flexibility was associated with more fat intake (P = .03) across all ages. Poorer decision making in children (P = .04), but not adolescents (P = .24), was associated with greater fat intake. Food-specific behavioural disinhibition, the ability to delay gratification for both food and monetary rewards, and working memory were not significantly associated with youth's disinhibited eating patterns during a single meal. CONCLUSIONS: Most domains of EF were not associated with youth's disinhibited eating. Significant associations may highlight the need to target specific cognitive processes, particularly behavioural disinhibition, decision making, and cognitive flexibility, in potential intervention strategies for children's disinhibited eating.

Early effects of roflumilast on insulin sensitivity in adults with prediabetes and overweight/obesity involve age-associated fat mass loss - results of an exploratory study.

PURPOSE: Roflumilast (Daliresp, Daxas) is a FDA-approved phosphodiesterase 4 (PDE4) inhibitor for the treatment of moderate-to-severe chronic obstructive pulmonary disease. In mice and in limited human studies, this oral medication can cause weight loss and improve insulin sensitivity. We set out to determine the mechanism of its effect on insulin sensitivity. PATIENTS AND METHODS: Eight adults with overweight/obesity and prediabetes received roflumilast for 6 weeks. Before and after roflumilast, subjects underwent tests of insulin sensitivity, mixed meal test, body composition, markers of inflammation, and mitochondria function. Dietary intake and physical activity were also assessed. Our primary outcome was the change in peripheral insulin sensitivity, as assessed by the hyper-insulinemic euglycemic clamp. RESULTS: This study was underpowered for the primary outcome. Pre- and post-roflumilast mean peripheral insulin sensitivity were 48.7 and 70.0 mg/g fat free mass/minute, respectively, (P-value=0.18), respectively. Among the mixed meal variables, roflumilast altered glucagon-like peptide 1 (GLP-1) hormone the most, although the average effect was not statistically significant (P=0.18). Roflumilast induced a trend toward significance in 1) decreased energy intake (from 11,095 KJ to 8,4555 KJ, P=0.07), 2) decreased fat mass (from 34.53 to 32.97 kg, P=0.06), 3) decreased total and LDL cholesterol (P=0.06 for both variables), and 4) increased plasma free fatty acids (from 0.40 to 0.50 mEq/L, P=0.09) The interval changes in adiposity and free fatty acid were significantly associated with the subject's age (P-value range= <0.001 to 0.02 for the correlations). Inflammatory and adhesion markers, though unchanged, significantly correlated with one another and with incretin hormones only after roflumilast. CONCLUSION: We demonstrate, for the first time in humans, increasing percentage of fat mass loss from roflumilast with increasing age in adults with prediabetes and overweight/obesity. We also demonstrate novel associations among roflumilast-induced changes in incretin hormones, inflammatory markers, peripheral insulin sensitivity, and adiposity. We conclude that roflumilast's early effects on insulin sensitivity is indirect and likely mediated through roflumilast's prioritization of lipid over glucose handling. CLINICAL TRIALS REGISTRATION: NCT01862029.

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.