Selecting an Ecological Momentary Assessment Platform: Tutorial for Researchers.

BACKGROUND: Although ecological momentary assessment (EMA) has been applied in psychological research for decades, delivery methods have evolved with the proliferation of digital technology. Technological advances have engendered opportunities for enhanced accessibility, convenience, measurement precision, and integration with wearable sensors. Notwithstanding, researchers must navigate novel complexities in EMA research design and implementation. OBJECTIVE: In this paper, we aimed to provide guidance on platform selection for clinical scientists launching EMA studies. METHODS: Our team includes diverse specialties in child and adolescent behavioral and mental health with varying expertise on EMA platforms (eg, users and developers). We (2 research sites) evaluated EMA platforms with the goal of identifying the platform or platforms with the best fit for our research. We created a list of extant EMA platforms; conducted a web-based review; considered institutional security, privacy, and data management requirements; met with developers; and evaluated each of the candidate EMA platforms for 1 week. RESULTS: We selected 2 different EMA platforms, rather than a single platform, for use at our 2 research sites. Our results underscore the importance of platform selection driven by individualized and prioritized laboratory needs; there is no single, ideal platform for EMA researchers. In addition, our project generated 11 considerations for researchers in selecting an EMA platform: (1) location; (2) developer involvement; (3) sample characteristics; (4) onboarding; (5) survey design features; (6) sampling scheme and scheduling; (7) viewing results; (8) dashboards; (9) security, privacy, and data management; (10) pricing and cost structure; and (11) future directions. Furthermore, our project yielded a suggested timeline for the EMA platform selection process. CONCLUSIONS: This study will guide scientists initiating studies using EMA, an in vivo, real-time research tool with tremendous promise for facilitating advances in psychological assessment and intervention.

A comparison of negative affect and disinhibited eating between children with and without parents with type 2 diabetes.

BACKGROUND: Children whose parents have type 2 diabetes (T2D) are at high-risk for developing T2D. In youth, negative affect has been shown to predict insulin resistance (IR), and disinhibited-eating behaviors have been linked to IR. It is unknown if youth with a parent with T2D (P-T2D) report greater psychological and behavioral symptoms than those without a P-T2D. OBJECTIVE: To compare youth with and without a P-T2D on symptoms of negative affect and disinhibited-eating. METHODS: Nine-hundred thirty-two youth (13.3 ± 2.6 years; BMIz 1.06 ± 1.06; 67.8% female; 53.6% people of color; 10.7% with a P-T2D) completed questionnaires of anxiety and depressive symptoms, eating in the absence of hunger, and emotional-eating. Loss-of-control (LOC)-eating was assessed by interview. In two separate subsamples, energy intake was explored using laboratory test meals simulating eating in the absence of hunger and LOC-eating, respectively. Analyses were adjusted for age, sex, race/ethnicity. In follow-up analyses, fat mass (kg) and height, and IR were included as covariates, respectively. RESULTS: Adjusting for all covariates including adiposity and IR, compared to youth without a P-T2D, youth with a P-T2D reported more anxiety and depression symptoms, greater eating in the absence of hunger, and emotional-eating (ps < 0.05). No significant differences were found for LOC-eating, or in exploratory analyses of energy intake for either test meal (ps > 0.16). CONCLUSIONS: Self-reported negative affect and disinhibited-eating may be higher among youth with P-T2D compared to those without P-T2D. Prospective studies should examine, among those with a P-T2D, what role such symptoms may play for their subsequent risk for T2D.

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.

Associations between latent trait negative affect and patterns of food-intake among girls with loss-of-control eating.

OBJECTIVE: Momentary negative affect (NA) has been shown to predict eating patterns in the laboratory, yet, more stable mood states have not been studied in relation to eating patterns in the laboratory among youth at high risk for binge-eating disorder and obesity. METHOD: One-hundred-eight adolescent girls (14.5 ± 1.7 years) with BMI between the 75th-97th percentile who reported loss-of-control (LOC)-eating completed measures of trait anxiety and depressive symptoms. Food-intake patterns were measured from a laboratory test meal (9,385 kcal). Latent factor analysis of depressive symptoms and trait anxiety was used to compute latent trait NA. Multivariate general linear models predicted total energy, snacks, and macronutrient intake from trait NA, adjusting for age, race, height, lean-mass, and percentage fat-mass. RESULTS: Trait NA was significantly positively related to total energy-intake, and, specifically, snacks, sweet snacks, and percentage sweet fats (ps ≤ .03), and negatively related to percentage protein consumed (p = .04). DISCUSSION: Expanding on affect theory, trait NA may relate to palatable food-intake among girls with LOC-eating. Further data are needed to determine whether those with LOC-eating and trait NA are at heightened risk for the development of binge-eating disorder and obesity.

Assessment of loss-of-control eating in healthy youth by interview and questionnaire.

OBJECTIVE: The aim of this study is to evaluate two questionnaires, an updated youth version of the questionnaire on eating and weight patterns (Questionnaire on Eating and Weight Patterns-5 Children/Adolescent [QEWP-C-5]) and the Loss-of-Control (LOC) Eating Disorder Questionnaire (LOC-ED-Q), against the Eating Disorder Examination (EDE) interview to assess the presence of LOC-eating among youth. METHOD: Two-hundred and eighteen youths (12.8 ± 2.7 years) completed the QEWP-C-5, LOC-ED-Q, and EDE, depressive and anxiety questionnaires, and adiposity assessment. Sensitivity, specificity, positive-predictive value, negative-predictive value, and diagnostic accuracy were calculated; Cochran's Q and McNemar's tests were used to compare measures. Receiver operating characteristic area under the curve (AUC) analyses were performed. Mood and adiposity based on LOC-eating presence and absence based on each measure were examined. RESULTS: The QEWP-C-5 and LOC-ED-Q demonstrated poor sensitivity (33%; 30%) and high specificity (95%; 96%) compared with the EDE. The AUCs suggested neither the QEWP-C-5 (0.64) nor the LOC-ED-Q (0.62) demonstrated acceptable diagnostic accuracy. Comparing distributions of LOC-eating presence between assessments, the QEWP-C-5 and EDE did not differ significantly (p = .10), while the LOC-ED-Q and EDE had significantly different distributions (p = .03). LOC-eating presence was associated with higher depressive and anxiety symptoms across all measures (ps < .02). Greater adiposity (ps < .02) was associated with LOC-eating presence on the EDE and LOC-ED-Q, and higher BMI z-score (p = .02) on the LOC-ED-Q. DISCUSSION: Neither the QEWP-C-5 nor the LOC-ED-Q was sensitive for identifying LOC-eating presence as determined by the EDE, although both were associated with greater mood symptoms. Research is needed to improve self-report questionnaires to better screen for LOC-eating presence among pediatric populations.

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.

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.

A genetic strategy for probing the functional diversity of magnetosome formation.

Model genetic systems are invaluable, but limit us to understanding only a few organisms in detail, missing the variations in biological processes that are performed by related organisms. One such diverse process is the formation of magnetosome organelles by magnetotactic bacteria. Studies of model magnetotactic α-proteobacteria have demonstrated that magnetosomes are cubo-octahedral magnetite crystals that are synthesized within pre-existing membrane compartments derived from the inner membrane and orchestrated by a specific set of genes encoded within a genomic island. However, this model cannot explain all magnetosome formation, which is phenotypically and genetically diverse. For example, Desulfovibrio magneticus RS-1, a δ-proteobacterium for which we lack genetic tools, produces tooth-shaped magnetite crystals that may or may not be encased by a membrane with a magnetosome gene island that diverges significantly from those of the α-proteobacteria. To probe the functional diversity of magnetosome formation, we used modern sequencing technology to identify hits in RS-1 mutated with UV or chemical mutagens. We isolated and characterized mutant alleles of 10 magnetosome genes in RS-1, 7 of which are not found in the α-proteobacterial models. These findings have implications for our understanding of magnetosome formation in general and demonstrate the feasibility of applying a modern genetic approach to an organism for which classic genetic tools are not available.

Eye-tracking measurement of attention bias to social threat among youth: A replication and extension study.

Attentional bias to social threat cues has been linked to heightened anxiety and irritability in youth. Yet, inconsistent methodology has limited replication and led to mixed findings. The current study aims to 1) replicate and extend two previous pediatric studies demonstrating a relationship between negative affectivity and attentional bias to social threat and 2) examine the test-retest reliability of an eye-tracking paradigm among a subsample of youth. Attention allocation to negative versus non-negative emotional faces was measured using a free-viewing eye-tracking task among youth (N=185 total, 60% female, M age=13.10 years, SD age=2.77) with three face-pair conditions: happy-angry, neutral-disgust, sad-happy. Replicating procedures of two previous studies, linear mixed-effects models compared attention bias between children with anxiety disorders and healthy controls. Bifactor analysis was used to parse shared versus unique facets of general negative affectivity (i.e., anxiety, irritability), which were then examined in relation to attention bias. Test-retest reliability of the bias-index was estimated among a subsample of youth (N=36). No significant differences in attention allocation or bias emerged between anxiety and healthy control groups. While general negative affectivity across the sample was not associated with attention bias, there was a positive relationship for anxiety and irritability on duration of attention allocation toward negative faces. Test-retest reliability for attention bias was moderate (r=0.50, p<.01). While anxiety-related findings from the two previous studies were not replicated, the relationship between attention bias and facets of negative affect suggests a potential target for treatment. Evidence for test-retest reliability encourages future use of the eye-tracking task for researchers.

A systematic review and meta-analysis of loss-of-control eating in relation to cardiometabolic health components and inflammatory markers.

INTRODUCTION: Loss-of-control (LOC) eating, or the subjective experience of being unable to stop eating, is a hallmark feature of binge-eating episodes, which are also characterized by consuming an unusually large amount of food. However, regardless of the size of eating episode, LOC-eating may be a risk factor for adverse health outcomes. This systematic review and meta-analysis comprehensively examine the relationship of LOC-eating with cardiometabolic health components and inflammatory markers. METHODS: Search procedures were conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines in six electronic databases. Studies of adult or youth samples published in English from the year 2000 onward were included. Given heterogeneity in age groups and adjustment for body mass index across studies, these factors were included as meta-regression moderators. RESULTS: Fifty-eight studies were identified through the literature search. Among individuals with (versus without) LOC-eating, relative risk ratios provided evidence of a greater relative risk for metabolic syndrome, hypertension, and dyslipidemia; standardized mean differences also provided evidence of higher waist circumference and impaired levels of fasting plasma glucose, high-density lipoprotein (HDL)-cholesterol, and triglycerides, but not blood pressure. Age group did not impact cardiometabolic health components. Body mass index differences moderated the effect on waist circumference. A narrative review of inflammatory markers revealed mixed findings linking inflammatory markers to LOC-eating. DISCUSSION: Overall, evidence for the relationship between LOC-eating and impaired cardiometabolic health underscores LOC-eating as an important early intervention target for prevention of serious adverse health outcomes.

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.

Desulfovibrio magneticus RS-1 contains an iron- and phosphorus-rich organelle distinct from its bullet-shaped magnetosomes.

Intracellular magnetite crystal formation by magnetotactic bacteria has emerged as a powerful model for investigating the cellular and molecular mechanisms of biomineralization, a process common to all branches of life. Although magnetotactic bacteria are phylogenetically diverse and their crystals morphologically diverse, studies to date have focused on a few, closely related species with similar crystal habits. Here, we investigate the process of magnetite biomineralization in Desulfovibrio magneticus sp. RS-1, the only reported species of cultured magnetotactic bacteria that is outside of the alpha-Proteobacteria and that forms bullet-shaped crystals. Using a variety of high-resolution imaging and analytical tools, we show that RS-1 cells form amorphous, noncrystalline granules containing iron and phosphorus before forming magnetite crystals. Using NanoSIMS (dynamic secondary ion mass spectroscopy), we show that the iron-phosphorus granules and the magnetite crystals are likely formed through separate cellular processes. Analysis of the cellular ultrastructure of RS-1 using cryo-ultramicrotomy, cryo-electron tomography, and tomography of ultrathin sections reveals that the magnetite crystals are not surrounded by membranes but that the iron-phosphorus granules are surrounded by membranous compartments. The varied cellular paths for the formation of these two minerals lead us to suggest that the iron-phosphorus granules constitute a distinct bacterial organelle.

Ecological Momentary Assessment of Youth Anxiety: Evaluation of Psychometrics for Use in Clinical Trials.

Background: Ecological momentary assessment (EMA) captures naturalistic experience in real time and holds promise to improve our understanding and treatment of youth psychopathology. While psychometric evaluation of EMA methods is crucial, particularly for use as a tool in clinical trials, research examining the reliability and validity of EMA items in youth is lacking. Method: This study evaluates EMA responses from 204 child and adolescent participants (M age = 12.54, 60.8% female), including 131 participants with an anxiety disorder and 73 participants with no psychiatric diagnosis. We assessed the within- and between-person variability, internal consistency, test-retest reliability, and convergent and discriminant validity of two EMA items probing anxiety symptoms; one positive affect item served as a comparison. Results: All psychometric properties of the anxiety items were at least satisfactory in youth with anxiety disorders. However, there was restricted variability and poor test-retest reliability in youth with no diagnosis. Discussion: These results might facilitate future clinical trials using EMA to investigate pediatric anxiety. Results also suggest that unique EMA items might be needed to reliably track anxiety in healthy youth. Future work should continue to examine the psychometric properties of EMA protocols before implementation in clinical trials. ClinicalTrials.gov identifier: NCT00018057.

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.

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.

MamK, a bacterial actin, forms dynamic filaments in vivo that are regulated by the acidic proteins MamJ and LimJ.

Bacterial actins, in contrast to their eukaryotic counterparts, are highly divergent proteins whose wide-ranging functions are thought to correlate with their evolutionary diversity. One clade, represented by the MamK protein of magnetotactic bacteria, is required for the subcellular organization of magnetosomes, membrane-bound organelles that aid in navigation along the earth's magnetic field. Using a fluorescence recovery after photobleaching assay in Magnetospirillum magneticum AMB-1, we find that, like traditional actins, MamK forms dynamic filaments that require an intact NTPase motif for their turnover in vivo. We also uncover two proteins, MamJ and LimJ, which perform a redundant function to promote the dynamic behaviour of MamK filaments in wild-type cells. The absence of both MamJ and LimJ leads to static filaments, a disrupted magnetosome chain, and an anomalous build-up of cytoskeletal filaments between magnetosomes. Our results suggest that MamK filaments, like eukaryotic actins, are intrinsically stable and rely on regulators for their dynamic behaviour, a feature that stands in contrast to some classes of bacterial actins characterized to date.

Associations of sleep with food cravings and loss-of-control eating in youth: An ecological momentary assessment study.

BACKGROUND: Inconsistent sleep patterns may promote excess weight gain by increasing food cravings and loss-of-control (LOC)-eating; however, these relationships have not been elucidated in youth. OBJECTIVE: We tested whether sleep duration and timing were associated with food cravings and LOC-eating. METHOD: For 14 days, youths wore actigraphy monitors to assess sleep and reported severity of food cravings and LOC-eating using ecological momentary assessment. Generalized linear mixed models tested the associations between weekly and nightly shifts in facets of sleep (i.e., duration, onset, midpoint, and waketime) and next-day food cravings and LOC-eating. Models were re-run adjusting for relevant covariates (e.g., age, sex, adiposity). RESULTS: Among 48 youths (12.88 ± 2.69 years, 68.8% female, 33.3% with overweight/obesity), neither weekly nor nightly facets of sleep were significantly associated with food cravings (ps = 0.08-0.93). Youths with shorter weekly sleep duration (est. ß = -0.31, p = 0.004), earlier weekly midpoints (est. ß = -0.47, p = 0.010) and later weekly waketimes (est. ß = 0.49, p = 0.010) reported greater LOC-eating severity; findings persisted in adjusted models. CONCLUSIONS: In youth, weekly, but not nightly, shifts in multiple facets of sleep were associated with LOC-eating severity; associations were not significant for food cravings. Sleep should be assessed as a potentially modifiable target in paediatric LOC-eating and obesity prevention programs.

Weight-based teasing in youth: Associations with metabolic and inflammatory markers.

BACKGROUND: Research among adults suggests that weight stigma is associated with worsened cardiometabolic health. However, these relationships have not been examined among youth. OBJECTIVE: Assess associations between weight-based teasing (WBT) and metabolic and inflammatory markers among two samples of youth: (1) a non-treatment-seeking sample and (2) a weight loss treatment-seeking sample with obesity. METHOD: Weight, height, adiposity, waist circumference and blood pressure were measured. Fasting blood samples were collected for metabolic (triglycerides, glucose, high-density lipoprotein cholesterol) and inflammatory analytes (high-sensitivity C-reactive protein in Study 1 and erythrocyte sedimentation rate in both studies). Youths completed the Perception of Teasing Scale, a measure of WBT. Metabolic and inflammatory indices were compared between those with and without teasing, adjusting for demographics and body composition. RESULTS: Study 1 enrolled 201 non-treatment-seeking youth (Mage = 13.1y; 54.2% female; 44.8% non-Hispanic White; 32.8% with overweight/obesity); 15.4% reported WBT. Study 2 enrolled 111 treatment-seeking adolescents with obesity (Mage = 14.0y; 66.7% female; 37.8% non-Hispanic White); 73.0% reported WBT. Adjusting for covariates, WBT was not associated with cardiometabolic risk factors in either study. CONCLUSIONS: WBT was not associated with worsened cardiometabolic health. Longitudinal research is needed to elucidate associations between WBT and health in youth.