Adrenocortical regulation, eating in the absence of hunger and BMI in young children

Stress-induced eating in rural adolescents: Unique variability among boys and adolescents with obesity

Stress may contribute to the development of obesity through its effects on dysregulated eating, although this has not yet been examined among low-income, rural adolescents. We examined adolescents' stress-induced changes in eating an ad libitum meal, and after, in the absence of hunger (EAH), and the extent to which these varied by sex, race, and weight status. Participants included 260 adolescents, drawn from a sample of rural households experiencing poverty. Adolescents completed two home visits while salivary cortisol was measured; during the control (low stress) visit, they completed questionnaires and procedures thought to elicit low levels of stress and had BMI assessed. During the stress visit, adolescents completed a 20-min set of psychosocial stress challenges before eating. At each visit, adolescents consumed an ad-libitum meal after which they were additionally given large portions of snacks (EAH task). Results revealed that indeed cortisol was higher during the stress visit, across the sample. Boys showed stress-induced increases during ad-libitum meal intake (for calories, fat, and carbohydrates) whereas girls exhibited decreased intake. Further, adolescents with obesity showed stress-induced increases in fat intake, but only when hunger was satiated (EAH). There were no differences by race. These findings provide the first evidence of stress-induced alterations in food intake in a rural, low-income sample of adolescents and point to a strong vulnerability for stress-induced increases in eating in rural boys as well as stress-induced increases in fat intake when satiated as a possible contributor to obesity in youth.

Unveiling stress markers: A systematic review investigating psychological stress biomarkers

Psychological stress is a ubiquitous facet of modern life, impacting individuals across diverse contexts and demographics. Understanding its physiological manifestations through biomarkers has gained substantial attention within the scientific community. A comprehensive search was conducted across multiple databases for peer-reviewed articles published within the past decade. Preliminary findings reveal many biomarkers associated with psychological stress across different biological systems, including the hypothalamic-pituitary-adrenal axis, immune system, cardiovascular system, and central nervous system. This systematic review explores psychological, physiological, and biochemical biomarkers associated with stress. Analyzing recent literature, it synthesizes findings across these three categories, elucidating their respective roles in stress response mechanisms. Psychological markers involve subjective assessments like self-reported stress levels, perceived stress scales, or psychometric evaluations measuring anxiety, depression, or coping mechanisms. Physiological markers include heart rate variability, blood pressure, and immune system responses such as cytokine levels or inflammatory markers. Biochemical markers involve hormones or chemicals linked to stress. It includes cortisol, catecholamines, copeptin, salivary amylase, IL-6, and C-reactive protein.

Examining links between child temperament and feeding, eating, and weight outcomes: An updated systematic review of the literature

BACKGROUND

Weight outcomes have been associated with child temperament, defined as individual differences in reactivity and self-regulation. The current systematic review aims to provide an updated summary of the evidence linking temperamental negative reactivity, surgency, and regulation superfactors to early childhood feeding, eating, and weight outcomes.

METHODS

PubMed, PsycINFO and Embase databases, as well as scientific meeting programs, were searched using keywords and subject headings. Publication dates were limited to 2012-2019 as prior reviews were published in 2012 and 2014. Identified studies were eligible if they included children ages 0-5 years, a measure of child temperament, and a measure of parent/caregiver feeding, child eating, or child weight. 7113 studies were identified and 121 met inclusion criteria.

RESULTS

Feeding, eating, and weight outcomes were largely unrelated to overarching negative reactivity, surgency, and effortful control superfactors. Examination of individual temperament dimensions suggested difficult temperament was frequently linked to non-responsive feeding practices, whereas elevated emotionality and decreased self-regulation were linked to maladaptive eating behaviors, and lower inhibitory control to adiposity. Analyses with infants reported greater percentages of significant associations compared to children, and cross-sectional studies generally reported fewer significant associations than other study designs.

CONCLUSIONS

Difficult temperament, greater emotionality and lower self-regulation and inhibitory control were the aspects of temperament most consistently related to poorer early childhood feeding, eating, and weight outcomes. Associations tended to be stronger in infancy, and when examined within a non-cross-sectional study design. Findings can inform the development of tailored efforts to promote healthy eating and growth throughout childhood.

A biobehavioral examination of emotional eating in adolescents: Evaluating the role of acute cortisol stress reactivity in the context of a multi-method assessment of eating in response to stress

Stress is linked to emotional eating among adolescents, which in turn increases risk for overweight/obesity (OW/OB) development and continuation. There is a lack of research disentangling chronic and acute stress as predictors of adolescent emotional eating. Further, there is a corresponding need to understand the effects of acute physiological stress reactivity within the context of adolescent emotional eating. The primary aim of this study was to examine the impact of cortisol stress reactivity on emotional eating in adolescents, above and beyond the effects of perceived chronic stress. The impact of subjective stress reactivity was also explored. Adolescents' (N = 49) intake of highly palatable snack foods was measured on separate control and stress-induction (following the Trier Social Stress Test for Children) days. A multi-method approach was used to assess objective (caloric intake) and subjective (self-report) emotional eating. Results indicated that greater cortisol reactivity, but not subjective stress reactivity, predicted subjective emotional eating, beyond the impact of chronic stress. Neither chronic stress nor subjective or objective stress reactivity predicted objective emotional eating following stress-induction. Findings point to the role of chronic stress and cortisol reactivity as risks for greater perceived emotional eating among adolescents, while elucidating differences between perceived and objective emotional eating. Future research should explore how chronic versus acute stress differentially contribute to adolescent weight management.

Factors Associated with Eating in the Absence of Hunger among Children and Adolescents: A Systematic Review

Eating in the absence of hunger (EAH) has been extensively studied over the past two decades and has been associated with excess body weight and the development of obesity. However, determinants of EAH remain uncertain. This systematic review aims to identify individual, familial, and environmental factors associated with EAH among children and adolescents. We included studies with a measure of EAH in participants aged 3-17 years old and including ≥1 factor associated with EAH. Our search identified 1494 articles. Of these, we included 81 studies: 53 cross-sectional, 19 longitudinal and nine intervention studies. In childhood (≤12 years old), EAH increases with age, it is greater in boys compared to girls, and it is positively associated with adiposity. Moreover, EAH development seems to be influenced by genetics. In adolescence, the number of studies is limited; yet, studies show that EAH slightly increases or remains stable with age, is not clearly different between sexes, and findings for overweight or obesity are less consistent across studies in adolescence. For familial factors, parental restrictive feeding practices are positively associated with EAH during childhood, mostly for girls. Studies assessing environmental factors are lacking and robust longitudinal studies spanning from early childhood to adolescence are needed.

Disinhibited Eating and Executive Functioning in Children and Adolescents: A Systematic Review and Meta-Analysis

A growing body of research suggests disinhibited eating and weaker executive function (EF) are two risk factors for pediatric obesity. Emerging brain imaging and behavioral findings support the notion that EF skills impact eating regulation. However, a major gap in the current literature is a synthesis of the association between various EF skills and disinhibited eating patterns across child development. To address this gap, a systematic review and meta-analysis was conducted to examine the effect of EF skills on disinhibited eating behaviors among youth ages 3-18 years old. PubMed and PsychINFO databases were utilized and data from 15 studies with a total sample of 4909 youth were included. A random effects meta-analysis revealed a small negative effect of overall EF skills on disinhibited eating behavior, r = -0.14, p < 0.01. Analysis of individual EF skills found working memory had an overall medium negative effect on disinhibited eating behavior, r = -0.25, p < 0.05. Taken together, findings from this meta-analysis support an inverse relationship between EF abilities and disinhibited eating patterns in children and adolescents, such that poorer EF abilities are associated with higher levels of disinhibited eating. Given the effect on eating behavior, future research is needed to assess whether EF difficulties may be a barrier to effective weight management in youth. Specifically, research is needed to examine whether EF skills may be a key target to consider for effective obesity prevention and treatment in children and adolescents.

Stress and eating responses in adolescent females predisposed to obesity: A pilot and feasibility study

OBJECTIVE

To explore how chronic stress, reactivity to acute stress, and obesogenic eating are linked in adolescent females predisposed to obesity.

METHODS

Participants included 21 adolescent females (m_age = 14.57 years) and their biological mothers with obesity (body mass index [BMI] ≥ 30 kg/m²). The pilot and feasibility study involved adolescent self-report of chronic stress, an acute stress-induction paradigm (Trier Social Stress Task, TSST), salivary cortisol collection to assess stress reactivity, and both subjective (self-report) and objective (snack buffet) measures of obesogenic eating.

RESULTS

Adolescent females reporting high chronic stress were significantly more likely to engage in self-reported emotional and external eating and to have higher food cravings (p's < .05) compared to adolescents with low chronic stress. Effect size estimates suggested a blunting effect of cortisol in the high chronic stress group. Blunted cortisol reactivity significantly predicted higher self-reported food cravings for the high chronic stress group (p = .04). Associations among chronic stress, cortisol, and self-reported and objective obesogenic eating reflected medium to large effect sizes.

CONCLUSIONS

This study built on limited extant research on stress and eating to demonstrate that chronic stress was associated with self-reported obesogenic eating patterns in adolescent females predisposed to obesity. Different patterns of cortisol reactivity and eating emerged depending on chronic stress group (low versus high). Understanding these eating patterns in the context of chronic stress can inform interventions to reduce obesity risks in adolescence.

Associations Between Different Cortisol Measures and Adiposity in Children: A Systematic Review and Meta-Analysis

This study examined associations between hair, salivary, serum, and urinary cortisol concentration with adiposity-related indicators in children, and explored their potential effects modification by age, sex, cortisol measurement method, and country developmental context. We systematically searched PubMed, Web of Science, and Embase for studies examining at least one of the four aforementioned cortisol with objectively measured adiposity-related outcomes in children. Meta-analyses of cross-sectional studies revealed that hair cortisol concentration was associated with fat mass index (FMI)-standard deviation score (SDS)/FMI z-score (pooled-β = 0.04, 95% CI: 0.01, 0.08) and BMI/BMI z-score (pooled-β = 0.15, 95% CI: 0.06, 0.25), and these associations were significant among children aged ≤ 12 years (pooled-β = 0.15, 95% CI: 0.05, 0.26) and >12 years (pooled-β = 0.13, 95% CI: 0.04, 0.22), children from developed countries (pooled β = 0.12, 95% CI: 0.03, 0.21) and developing countries (pooled-β = 0.193, 95% CI: 0.188, 0.198), and in studies extracting cortisol via LC-MS/MS (pooled-β = 0.18, 95% CI: 0.06, 0.29) but not ELISA (pooled-β = 0.08, 95% CI: −0.06, 0.22). Meta-analyses of both cohort and cross-sectional studies revealed non-significant associations of morning salivary cortisol concentration and total daily cortisol output with BMI/BMI z-score. Serum cortisol concentration was not associated with BMI or waist circumference. Meta-analysis of urinary cortisol concentration and adiposity was hindered by insufficient data. These findings further corroborate understanding of chronic stress’ physiological contribution to increased pediatric obesity risk.

Children's inhibitory control abilities in the presence of rewards are related to weight status and eating in the absence of hunger

The Reflective-Impulsive Dual Processes Model suggests that overeating occurs when the temptation to consume food overrides inhibitory control processes. However, how rewards interact with inhibitory control and their relation to children's weight status and food intake is not understood. Here, 7-to-11-year-old children (n = 66; 32 overweight/obese) completed two versions (baseline [i.e., non-reward incentivized/control] and reward incentivized [food, money, no reward]) of a Go/Nogo task. Intake of palatable foods in the absence of hunger (i.e., eating in the absence of hunger-EAH) was measured following a standardized meal. A drift diffusion model was used to characterize children's performance parameters on the Go/Nogo. On the baseline Go/Nogo, children with higher weight status responded more cautiously, but on reward trials for food/money children were more cautions and made more false alarms relative to the no reward condition. Energy intake during EAH positively correlated with FA errors for food and money vs. no reward, but sex moderated this effect such that FA positively associated with EAH in girls but not boys. Independent of sex, FA for money vs. no reward and food vs. money were both positively associated with energy consumed during EAH. These results suggest that the presence of food and money rewards impair inhibitory control processing, especially in children with higher weight status. Further, increased inhibitory control impairment in response to food rewards, specifically, may be a risk factor for disinhibited eating in girls. Though preliminary, results may be useful in the development of targeted treatments to help moderate excess consumption in children.

Does temperament make children differently susceptible to their home physical food environment? A cross-sectional DAGIS study on 3-6 year old Finnish children's food consumption

Consistently linked with children's food consumption are food availability and accessibility. However, less is known about potential individual differences among young children in their susceptibility to home food environments. The purpose of the study was to examine whether the association between home food availability and accessibility of sugar-rich foods and drinks (SFD) or fruits and vegetables (FV) and children's consumption of these foods differ according to their temperament. The study used two cross-sectional datasets collected as part of the Increased Health and Wellbeing in Preschools (DAGIS) study: 1) a cross-sectional data of 864 children aged 3-6 years old collected between fall 2015 and spring 2016, and 2) an intervention baseline data of 802 children aged 3-6 collected in fall 2017. Parents reported their children's temperament, consumption of FV and SFD, and home availability and accessibility of SFD and FV. Examination of whether associations between home availability and accessibility of FV and their consumption differ according to children's temperament involved using linear regression models. Similar models were used to examine association between home availability and accessibility of SFD and their consumption, and the moderating role of temperament. The association between home accessibility of SFD and their consumption frequency was dependent on the level of children's negative affectivity. More frequent consumption of SFD was observed with higher home accessibility of SFD. The association was stronger in children with higher scores in negative affectivity. No other interactions were found. Children with higher negative affectivity are possibly more vulnerable to food cues in the home environment than children with lower negative affectivity. Consideration of children's individual characteristics is necessary in supporting their healthy eating.

The influence of temperament on stress-induced emotional eating in children

Background

Stress‐induced emotional eating is a risk factor for overweight and obesity. Previous research proposes both the human serotonin transporter gene (5‐HTTLPR) and child's reactive temperament are promising candidates to help explain individual differences in stress‐induced emotional eating and weight. Understanding the association between specific genotypes, reactive temperament factors, and stress‐induced emotional eating may inform the development of personalized and effective treatment for children who may be at risk for overweight and obesity.

Objective

The current study explored the conditional indirect effect of genetic and environmental susceptibility (i.e., the interaction between 5‐HTTLPR and reactive temperament) on weight (as measured by percent body fat) mediated by stress‐induced emotional eating.

Method

One hundred and forty‐seven children (4 to 6 years old; 50.3% female; 22.4% Hispanic), along with their primary caregiver, completed laboratory tasks and questionnaires that assessed the child's reactive temperament, stress‐induced emotional eating, and percent body fat.

Results

The interaction between 5‐HTTLPR and impulsivity as well as with negative affectivity significantly predicted percent body fat. The interaction between 5‐HTTLPR and impulsivity as well as with negative affectivity significantly predicted both total calorie consumption and rate of total calorie consumption. However, the mediation aspect of this statistical model was not supported.

Conclusions

Child reactive temperament is an important indicator of how children approach eating when stressed. Mental health providers may consider prescribing strategies to reduce emotional eating among children with the SL variant and moderate to high impulsivity as well as children with the LL variant and high negative affectivity.

Do stressed children have a lot on their plates? A cross-sectional study of long-term stress and diet among Finnish preschoolers

We examined the association between hair cortisol concentration (HCC) - an indicator of long-term stress - and diet among preschoolers in a cross-sectional design. The participants were 597 Finnish 3-6-year-olds, and the data were collected in 2015-16. We used 4-cm hair samples to analyze HCC during the past four months. Food consumption was assessed using a food frequency questionnaire, and we used consumption frequencies of selected food groups as well as data-driven dietary pattern scores in the analyses. The parents of the participating children reported their educational level and family income. The researchers measured the children's weight and height. We examined the associations between HCC and diet using multilevel linear mixed models adjusted for age, gender, the highest education in the family, household relative income, and child BMI. Higher HCCs were associated with less frequent consumption of fruit and berries (B estimate -1.17, 95% CI -2.29, -0.05) and lower scores in a health-conscious dietary pattern (B estimate -0.38, 95% CI -0.61, -0,14). Higher HCCs were also associated with more frequent consumption of sugary beverages (B estimate 1.30, 95% CI 0.06, 2.54) in a model adjusted for age, gender and highest education in the family, but the association attenuated after further adjustments. Our results are parallel with previous studies that show a link between stress and unhealthy diet. In the future, longitudinal studies are needed to establish a causal relationship between stress and diet among children.

Exploring the effects of daily hassles on eating behaviour in children: The role of cortisol reactivity

It is well established that stress is positively associated with unhealthy eating behaviours and that cortisol reactivity to stress has been found to influence the stress-eating relationship in adults. However, there is a paucity of research that has explored the daily stress-cortisol-eating relationship amongst children. Therefore, the current study aimed to explore whether the experience of daily stressors was associated with an increase in between-meal snack consumption in children over 7 days. Individual cortisol reactivity to stress in the laboratory was explored as a potential moderator of the stress-eating relationship in the real world. Twenty 8-11 year old children completed the Trier Social Stress Test (for children, TSST-C) during which 4 salivary cortisol samples were taken. Participants subsequently completed a 7-day diary that recorded daily hassles (stressors) and between-meal snack consumption. Using multi-level modelling, the results showed there were no effects of daily hassles or mood on snack consumption. However, there were cross-level interactions, such that individuals who had higher cortisol reactivity to stress in the laboratory were found to consume more total and unhealthy snacks in naturalistic settings on days with high hassles and more negative mood compared to those who exhibited low and moderate cortisol reactivity to stress. This exploratory study provides novel evidence that cortisol reactivity to stress is an important moderator of stress-eating relationship in children and that daily diary approaches are feasible in studies investigating stress and eating in children aged 8-11 years old.

The Mediating Effect of Self-Regulation in the Association Between Poverty and Child Weight: A Systematic Review

Deficits in self-regulation (SR) have been proposed as a potential contributor to child overweight/obesity, a public health concern that disproportionately affects children living in poverty. Although poverty is known to influence SR, SR has not been considered as a potential mechanism in the association between poverty and child obesity. The aim of the current paper was to systematically review the current literature to determine whether SR is a viable mechanism in the relationship between child exposure to poverty and later risk of overweight/obesity. We systematically review and summarize literature in three related areas with the aim of generating a developmentally informed model that accounts for the consistent association between poverty and child weight, specifically how: (1) poverty relates to child weight, (2) poverty relates to child SR, and (3) SR is associated with weight. To quantify the strength of associations for each pathway, effect sizes were collected and aggregated. Findings from the studies included suggest small but potentially meaningful associations between poverty and child SR and between SR and child weight. The conceptualization and measurement of SR, however, varied across literature studies and made it difficult to determine whether SR can feasibly connect poverty to child obesity. Although SR may be a promising potential target for obesity intervention for low-income children, additional research on how SR affects risk of obesity is crucial, especially based on the lack of success of the limited number of SR-promoting interventions for improving children's weight outcomes.

Longitudinal associations between overweight/obesity and stress biology in low-income children

Background/Objectives

Associations between overweight and altered stress biology have been reported cross-sectionally during childhood, but it is unclear whether overweight precedes altered stress biology or if altered stress biology predicts greater likelihood of overweight over time. The current longitudinal study investigates associations between overweight/obesity, salivary alpha amylase and cortisol morning intercept, diurnal slope, and reactivity to social stress in a cohort of low-income children during preschool and middle childhood.

Subjects/Methods

Children were recruited through Head Start and were observed and followed into middle childhood (N = 257; M = 8.0 years). Height and weight were measured at both time points. Saliva samples were collected across the day and in response to a social challenge at both ages for alpha amylase and cortisol determination.

Results

Cross-lagged panel analyses indicated that overweight/obesity at preschool predicted lower morning alpha amylase (β = −0.18, 95% CI: −0.34, −0.03; p = .023), lower morning cortisol (β = −0.22, 95% CI: −0.38, −0.06; p = .006), lower sAA diurnal slope (β = −0.18, 95% CI: −0.34, −0.03; p = .021), and lower cortisol stress reactivity (β = −0.19, 95% CI: −0.35, −0.02; p = .031) in middle childhood. Lower alpha amylase reactivity at preschool was the only biological factor that predicted higher likelihood of overweight/obesity at middle childhood (β = −0.20, 95% CI: −0.38, −0.01; p = .035).

Conclusions

These findings suggest that overweight/obesity may be driving changes in stress biology across early to middle childhood, particularly in down-regulation of morning levels of stress hormones, diurnal sAA slope, and cortisol reactivity to stress, rather than stress biology driving overweight/obesity.

Weight status moderates stress-eating in the absence of hunger associations in children

OBJECTIVE

The association between stress and eating remains unclear in children potentially due to factors that may moderate the association. We examined whether weight status or sex moderated associations between response to a stress induction and eating in the absence of hunger (EAH), among low-income children.

METHOD

Children (n = 223; M age = 7.8 years, SD = 0.7 years) participated in a stress induction protocol (modified Trier Social Stress Test for Children [TSST-C]) during which behavioral coding of observed anxiety and change in self-reported distress were measured. Afterwards, participants completed a standardized EAH protocol where they were offered palatable foods. Total kilocalories consumed during the EAH protocol was calculated. Weight and height were measured and weight status calculated as overweight (BMI ≥ 85th percentile for age and sex) vs. not overweight. Multivariate linear regression models adjusting for covariates were conducted to test whether child weight status or sex moderated the stress response-EAH association, for both stress response variables.

RESULTS

Weight status moderated the association between observed stress response and EAH such that children with overweight engaged in more EAH as observed anxiety increased, whereas children without overweight engaged in less EAH as observed anxiety increased (β_interaction = 0.48; p = .010). Weight status did not moderate associations between self-reported distress and EAH. Child sex was not a significant moderator.

CONCLUSIONS

After exposure to stress, children with overweight in middle childhood may eat more palatable food compared to children without overweight, possibly due to hypersensitization to food cues or weight stigma experienced by youth with overweight. It may be helpful to encourage youth with overweight to engage in stress-management techniques that do not involve eating as a response to stress.

The Influence of Psychological Stress, Depressive Symptoms, and Cortisol on Body Mass and Central Adiposity in 10- to-12-Year-Old Children

PURPOSE

The purpose of this study was to examine the influence of psychological stress and depressive symptoms on body mass and central adiposity in 10-to-12-year-old children and to determine the mediating role of cortisol in the relationships among psychological stress, depressive symptoms, body mass, or central adiposity.

DESIGN AND METHODS

The convenience sample included 147 children (84 females; 63 males) who were recruited from one middle school and three elementary schools in a rural area of a southeastern state. Height, weight, waist circumference (WC), and salivary cortisol were measured. Children completed the Rating Scale for Pubertal Development for screening, Children's Depression Inventory, and the Feel Bad Scale. Bivariate correlation, multiple regression analyses, and univariate regression techniques were used in data analyses.

RESULTS

A positive relationship between psychological stress and depressive symptoms (r = 0.559, p < .001) was found. Depressive symptoms explained a significant amount of the variance in body mass index (BMI) (β = 0.37, p ≤.001) and central adiposity (β = 0.40, p ≤ .001) when sex, race/ethnicity, puberty, and socioeconomic status were controlled. No statistically significant relationships were found between psychological stress and cortisol or between depressive symptoms and cortisol.

CONCLUSIONS

Depressive symptoms were reported by normoweight, overweight, and obese children. Depressive symptoms accounted for variance in body mass and central adiposity. Practice Implications In addition to regular screening of BMI and WC, nurses and other health care professionals need to consider psychological factors that contribute to childhood obesity.

Psychosocial stress promotes food intake and enhances the neuroenergetic level in men

Psychosocial stress may lead to increased food consumption and overweight. In turn, obesity is related to reduced brain energy content. We hypothesized that psychosocial stress influencing food intake may alter the neuroenergetic status in the human brain. We tested 14 healthy normal weight men in a randomized crossover design. A modified version of the Trier Social Stress Test (TSST) was carried out to induce psychosocial stress vs. control in a neuroimaging setting. Cerebral energy content, i.e. high energy phosphates adenosine triphosphate (ATP) and phosphocreatine (PCr), was measured by ³¹phosphorus magnetic resonance spectroscopy. Food intake was quantified by an ad libitum buffet test. Stress hormonal response and alterations in glucose metabolism were monitored by blood sampling. Before data collection, we mainly expected a stress-induced reduction in cerebral high energy phosphates, followed by higher food intake. Psychosocial stress increased serum cortisol concentrations (p = .003) and fat intake of all participants by 25% (p = .043), as well as food intake of "stress-eaters" by 41.1% (p = .003) compared with controls. Blood glucose and insulin concentrations were not affected (p > .174 for both). Cerebral ATP and PCr levels generally increased upon stress-induction (p > = .022 and p = .037, respectively). Our data confirm that psychosocial stress may enhance food intake. Contrary to our expectations, stress induces a distinct increase in the neuroenergetic status. This insight suggests that the underlying central nervous mechanisms of stress-induced overeating may involve the regulation of the brain energy homeostasis.

Diurnal Cortisol Concentrations and Growth Indexes of 12- to 48-Month-Old Children From Mexico City

Context

Early life cortisol plays an important role in bone, muscle, and fat mobilization processes, which could influence body composition, affecting anthropometric indicators such as weight and height.

Objective

To explore the association between diurnal cortisol levels and growth indexes in children from 12 to 48 months of age.

Design

This study includes data from 404 children from the Programming Research in Obesity, Growth, Environment and Social Stressors Mexican birth cohort. Cortisol was measured in eight saliva samples collected at four time points during the day (from wakeup to bedtime), over 2 days, when the child was either 12, 18, or 24 months old. Total daytime cortisol levels were calculated by averaging the area under the curve (AUC) for the 2 days. Height and weight were measured from 12 to 48 months of age. Growth indexes were constructed according to z scores following World Health Organization standards: weight-for-age z score (Z-WFA), height/length-for-age z score, weight-for-height/length z score (Z-WFH), and body mass index-for-age z score (Z-BMIFA). Mixed models were used to analyze the association between cortisol AUC quartiles and growth indexes.

Results

Cortisol showed an inverted U-shaped association with the four growth indexes. Compared with the first quartile, all quartiles had a positive association with indexes that include weight, with the second quartile having the strongest association, resulting in an average change of β (95% CI) 0.38 (0.13-0.64) for Z-WFA, 0.36 (0.10-0.62) for Z-WFH, and 0.43 (0.17-0.69) for Z-BMIFA.

Conclusions

Results suggest that early life daytime cortisol levels, as a reflection of hypothalamic-pituitary-adrenal axis development, might influence growth in early infancy.

Pathways of Association from Stress to Obesity in Early Childhood

OBJECTIVE

The objective of this study is to critically review the literature on early life stress in relation to obesity in humans, including the multiple biological and behavioral mechanisms through which early life stress exposure (birth to the age of 5 years) may associate with obesity risk during childhood.

METHODS

A review of the literature was conducted to identify studies on associations between early childhood stress and risk for obesity and the mechanisms of association. Multiple databases (PubMed, PsycInfo, Google Scholar) were used in the search as well as a "snowball" search strategy. All study designs were included.

RESULTS

Early life stress and adverse childhood experiences are associated with obesity and overweight in adults. Evidence is less consistent in children. Studies vary in the nature of the stress examined (e.g., chronic vs. acute), sample characteristics, and study designs. Longitudinal studies are needed, as the effects of early life stress exposure may not emerge until later in the life-span. Early life stress exposure is associated with biological and behavioral pathways that may increase risk for childhood obesity.

CONCLUSIONS

There is evidence that early life stress is associated with multiple biological and behavioral pathways in children that may increase risk for later obesity. Little work has detailed the interconnections among these mechanisms across development or identified potential moderators of the association. Mapping the mechanisms connecting early life stress exposure to obesity risk in young children longitudinally should be a priority for obesity researchers. Recommendations for developmentally sensitive approaches to research that can inform obesity prevention strategies are presented.

Is brain response to food rewards related to overeating? A test of the reward surfeit model of overeating in children

The reward surfeit model of overeating suggests that heightened brain response to rewards contributes to overeating and subsequent weight gain. However, previous studies have not tested whether brain response to reward is associated with food intake, particularly during childhood, a period of dynamic development in reward and inhibitory control neurocircuitry. We conducted functional magnetic resonance imaging (fMRI) with 7-11-year-old children (n = 59; healthy weight, n = 31; overweight, n = 28; 54% female) while they played a modified card-guessing paradigm to examine blood-oxygen-level-dependent (BOLD) response to anticipating and winning rewards (food, money, neutral). Food intake was assessed at three separate meals that measured different facets of eating behavior: 1) typical consumption (baseline), 2) overindulgence (palatable buffet), and 3) eating in the absence of hunger (EAH). A priori regions of interest included regions implicated in both reward processing and inhibitory control. Multiple stepwise regressions were conducted to examine the relationship between intake and BOLD response to rewards. Corrected results showed that a greater BOLD response in the medial prefrontal cortex for anticipating food compared to money positively correlated with how much children ate at the baseline and palatable buffet meals. BOLD response in the dorsolateral prefrontal cortex for winning food compared to money was positively correlated with intake at the palatable buffet meal and EAH. All aforementioned relationships were independent of child weight status. Findings support the reward surfeit model by showing that increased brain response to food compared to money rewards positively correlates with laboratory measures of food intake in children.

Chronic Stress in Children and Adolescents: A Review of Biomarkers for Use in Pediatric Research

PROBLEM

Incorporating biomarkers of chronic stress into pediatric research studies may help to explicate the links between exposure to adversity and lifelong health, but there are currently very few parameters to guide nurse researchers in choosing appropriate biomarkers of chronic stress for use in research with children and adolescents.

METHODS

Biomarkers of chronic stress are described, including primary mediators (glucocorticoids, catecholamines, and cytokines) and secondary outcomes (neurologic, immune, metabolic, cardiovascular, respiratory, and anthropometric) of the chronic stress response.

RESULTS

Evidence of the use of each biomarker in pediatric research studies is reviewed. Recommendations for pediatric researchers, including selection of appropriate biomarkers, measurement considerations, potential moderators, and future directions for research, are presented.

DISCUSSION

A wide range of biomarkers is available for use in research studies with children. While primary mediators of chronic stress have been frequently measured in studies of children, measurement of secondary outcomes, particularly immune and metabolic biomarkers, has been limited. With thoughtful and theoretically based approaches to selection and measurement, these biomarkers present an important opportunity to further explore the physiologic pathways linking exposure to chronic stress with later health and disease.

CONCLUSION

The incorporation of chronic stress biomarkers into pediatric research studies may provide valuable insight into the mechanisms through which stressful environments "get under the skin" and ultimately inform efforts to promote health and reduce inequities among children exposed to adversity.

Externalizing behavior is prospectively associated with intake of added sugar and sodium among low socioeconomic status preschoolers in a sex-specific manner

BACKGROUND

High intake of added sugar and sodium is a public health concern for preschool-aged children living in the US. Externalizing behavior may predict higher consumption of added sugar and/or sodium; however, previous studies have mostly been cross-sectional. The aim was to evaluate whether externalizing behavior is prospectively related to added sugar and intake in a sex-specific manner among preschoolers.

METHODS

This was a secondary analysis of 524 preschool children (48% male) from Michigan who participated in an obesity prevention trial that occurred during one school year from 2011 to 2015. Teacher-assessed externalizing behaviors and three 24-h dietary recalls were completed at baseline and follow-up. We used linear mixed effects regression to evaluate the association between externalizing behavior at baseline and added sugar (% of total Calories) and sodium intake (mg/1000 Calories) at follow-up. In adjusted analysis, we included baseline income-to-needs ratio, child race/ethnicity, and baseline overweight status. All models were adjusted for total energy intake and accounted for clustering by classroom.

RESULTS

Baseline externalizing behavior was positively associated with added sugar intake at follow-up among boys; after adjustment for confounders, every 5 points lower externalizing T-score (corresponding to higher externalizing behavior) was associated with a 0.6 higher percentage of added sugar per total Calories (95% CI 0.2 to 1.1; P value = 0.004). In contrast, girls with higher levels of externalizing behavior had lower consumption of added sugars; after confounder adjustment, every 5 points lower externalizing T-score was related to 0.6 lower percentage intake (95% CI -1.0 to -0.1; P value = 0.01). Baseline externalizing behavior was inversely associated with sodium intake at follow-up among boys. After potential confounder adjustment, for every 5 points lower externalizing behavior T-score, there was a 22 mg/1000 Cal lower sodium intake (95% CI -45 to 1; P value = 0.06). In contrast, after adjustment for confounders, every 5 points lower externalizing T-score among girls was related to 24 mg/1000 Cal higher sodium intake (95% CI 1 to 46; P value = 0.04).

CONCLUSIONS

Externalizing behavior among preschool-aged children was prospectively related to added sugar and sodium intake in a sex-dependent manner.

TRIAL REGISTRATION

NCT01398358 Registered 19 July 2011.

What constitutes effective coping and efficient physiologic regulation following psychosocial stress depends on involuntary stress responses

This study utilized a random-assignment experimental design to examine the interactive contributions of youth-reported trait involuntary stress responses (ISRs) and effortful coping on physiologic reactivity and recovery patterns in preadolescent boys and girls. Fourth- and fifth-grade child-parent dyads (N=126) participated in this study. Children were exposed to the Trier Social Stress Test (TSST-C) and then to one of two randomly-assigned experimental coping conditions: behavioral distraction and cognitive avoidance. Children's ISRs were examined as predictors of salivary cortisol and alpha-amylase (sAA) reactivity as well as moderators of the effect of coping condition on cortisol and sAA recovery trajectories. Multi-level modeling analyses did not link ISRs to physiologic reactivity patterning. ISRs and coping condition interacted to predict differential physiologic recovery trajectories. In the distraction condition, children reporting high ISR levels displayed less efficient cortisol and sAA recovery than children reporting low ISR levels. Surprisingly, the opposite was found for children reporting high ISR levels in the avoidance condition. These children displayed more efficient physiologic recovery relative to their high ISR level peers in the distraction condition. Findings suggest that the efficiency of preadolescents' physiologic recovery following stress may depend on regulatory fit between children's ISR levels and cues from their coping environment.

HPA Axis Interactions with Behavioral Systems

Perhaps the most salient behaviors that individuals engage in involve the avoidance of aversive experiences and the pursuit of pleasurable experiences. Engagement in these behaviors is regulated to a significant extent by an individual's hormonal milieu. For example, glucocorticoid hormones are produced by the hypothalamic-pituitary-adrenocortical (HPA) axis, and influence most aspects of behavior. In turn, many behaviors can influence HPA axis activity. These bidirectional interactions not only coordinate an individual's physiological and behavioral states to each other, but can also tune them to environmental conditions thereby optimizing survival. The present review details the influence of the HPA axis on many types of behavior, including appetitively-motivated behaviors (e.g., food intake and drug use), aversively-motivated behaviors (e.g., anxiety-related and depressive-like) and cognitive behaviors (e.g., learning and memory). Conversely, the manuscript also describes how engaging in various behaviors influences HPA axis activity. Our current understanding of the neuronal and/or hormonal mechanisms that underlie these interactions is also summarized. © 2016 American Physiological Society. Compr Physiol 6:1897-1934, 2016.

From Bench to Bedside: Understanding Stress-Obesity Research Within the Context of Translation to Improve Pediatric Behavioral Weight Management

A growing body of literature suggests that stress, including chronic stress and acute physiologic stress reactivity, is one contributor to the development and maintenance of obesity in youth. Little has been done to apply the literature on stress and obesity risk to inform the development of pediatric behavioral weight control (BWC) interventions. The aims of this review are to (1) discuss research linking stress and pediatric obesity, (2) provide examples of the implications of the stress-obesity research for pediatric BWC development, and (3) propose that a mindfulness-based approach may be useful in targeting stress reduction within pediatric BWC.

Parental control and overconsumption of snack foods in overweight and obese children

The associations between snack food consumption, parent feeding practices and general parenting in overweight in obese children are largely unknown. Therefore, we examined these relationships in 117 treatment-seeking overweight and obese children (10.40 ± 1.35 years; 53% female; 52% Caucasian; BMI-z: 2.06 ± .39). Children consumed a dinner meal, completed an Eating in the Absence of Hunger (EAH) free access paradigm (total EAH intake = EAH%-total; sweet food intake = EAH%-sweet), and completed the Child Report of Parent Behavior Inventory. Parents completed the Child Feeding Questionnaire. Child EAH%-total and EAH%-sweet were positively associated with dinner consumption (p's < .01). Girls had significantly higher EAH%-total compared to boys (p < .05). In separate models, higher EAH%-total was associated with greater use of maternal psychological control (p < .05) and EAH%-sweet was positively associated with parent monitoring (p < .05). In analyses examining factors associated with the consumption of specific foods, EAH snack food, parent restriction, pressure to eat, monitoring, and maternal psychological control were positively correlated with intake of Hershey's(®) chocolate bars (p's < .05). In summary, parental monitoring is associated with child sweet snack food intake and maternal psychological control is associated with child total snack food consumption. Future research should evaluate the complex relationship between child eating and parenting, especially with regard to subgroups of foods.

Low Childhood Socioeconomic Status Promotes Eating in the Absence of Energy Need

Life-history theory predicts that exposure to conditions typical of low socioeconomic status (SES) during childhood will calibrate development in ways that promote survival in harsh and unpredictable ecologies. Guided by this insight, the current research tested the hypothesis that low childhood SES will predict eating in the absence of energy need. Across three studies, we measured (Study 1) or manipulated (Studies 2 and 3) participants’ energy need and gave them the opportunity to eat provided snacks. Participants also reported their SES during childhood and their current SES. Results revealed that people who grew up in high-SES environments regulated their food intake on the basis of their immediate energy need; they ate more when their need was high than when their need was low. This relationship was not observed among people who grew up in low-SES environments. These individuals consumed comparably high amounts of food when their current energy need was high and when it was low. Childhood SES may have a lasting impact on food regulation.

Mindless feeding: Is maternal distraction during bottle-feeding associated with overfeeding?

Mindless eating, or eating while distracted by surrounding stimuli, leads to overeating. The present study explored whether "mindless feeding," or maternal distraction during bottle-feeding, is associated with greater infant formula/milk intakes and lower maternal sensitivity to infant cues. Mothers and their ≤24-week-old bottle-feeding infants (N = 28) visited our laboratory for a video-recorded feeding observation. Infant intake was assessed by weighing bottles before and after the feedings. Maternal sensitivity to infant cues was objectively assessed by behavioral coding of video-records using the Nursing Child Assessment Feeding Scale. Maternal distraction was defined as looking away from the infant >75% of the feeding; using a mobile device; conversing with another adult; or sleeping. Twenty-nine percent (n = 8) of mothers were distracted. While differences in intakes for infants of distracted vs. not distracted mothers did not reach significance (p = 0.24), the association between distraction and infant intake was modified by two dimensions of temperament: orienting/regulation capacity (p = 0.03) and surgency/extraversion (p = 0.04). For infants with low orienting/regulation capacity, infants of distracted mothers consumed more (177.1 ± 33.8 ml) than those of not distracted mothers (92.4 ± 13.8 ml). Similar findings were noted for infants with low surgency/extraversion (distracted: 140.6 ± 22.5 ml; not distracted: 78.4 ± 14.3 ml). No association between distraction and intake was seen for infants with high orienting/regulation capacity or surgency/extraversion. A significantly greater proportion of distracted mothers showed low sensitivity to infant cues compared to not distracted mothers (p = 0.04). In sum, mindless feeding may interact with infant characteristics to influence feeding outcomes; further experimental and longitudinal studies are needed.

Stress, behavior, and biology: risk factors for cardiovascular diseases in youth

Psychological stress reactivity is associated with atherogenesis in youth. The novel hypothesis is that stress promotes atherogenic behaviors, including snacking on energy-dense food and reducing physical activity, and increases adiposity. Stress also increases systolic blood pressure cardiovascular reactivity, which also may be atherogenic. Exercise dampens stress reactivity and may be one mechanism by which it protects against the development of cardiovascular diseases.

Stress exposure, food intake and emotional state

This manuscript summarizes the proceedings of the symposium entitled, "Stress, Palatable Food and Reward", that was chaired by Drs. Linda Rinaman and Yvonne Ulrich-Lai at the 2014 Neurobiology of Stress Workshop held in Cincinnati, OH. This symposium comprised research presentations by four neuroscientists whose work focuses on the biological bases for complex interactions among stress, food intake and emotion. First, Dr Ulrich-Lai describes her rodent research exploring mechanisms by which the rewarding properties of sweet palatable foods confer stress relief. Second, Dr Stephanie Fulton discusses her work in which excessive, long-term intake of dietary lipids, as well as their subsequent withdrawal, promotes stress-related outcomes in mice. Third, Dr Mark Wilson describes his group's research examining the effects of social hierarchy-related stress on food intake and diet choice in group-housed female rhesus macaques, and compared the data from monkeys to results obtained in analogous work using rodents. Finally, Dr Gorica Petrovich discusses her research program that is aimed at defining cortical-amygdalar-hypothalamic circuitry responsible for curbing food intake during emotional threat (i.e. fear anticipation) in rats. Their collective results reveal the complexity of physiological and behavioral interactions that link stress, food intake and emotional state, and suggest new avenues of research to probe the impact of genetic, metabolic, social, experiential and environmental factors on these interactions.

Weight loss by calorie restriction versus bariatric surgery differentially regulates the hypothalamo-pituitary-adrenocortical axis in male rats

Behavioral modifications for the treatment of obesity, including caloric restriction, have notoriously low long-term success rates relative to bariatric weight-loss surgery. The reasons for the difference in sustained weight loss are not clear. One possibility is that caloric restriction alone activates the stress-responsive hypothalamo-pituitary-adrenocortical (HPA) axis, undermining the long-term maintenance of weight loss, and that this is abrogated after bariatric surgery. Accordingly, we compared the HPA response to weight loss in five groups of male rats: (1) high-fat diet-induced obese (DIO) rats treated with Roux-en-Y gastric bypass surgery (RYGB, n = 7), (2) DIO rats treated with vertical sleeve gastrectomy (VSG, n = 11), (3) DIO rats given sham surgery and subsequently restricted to the food intake of the VSG/RYGB groups (Pair-fed, n = 11), (4) ad libitum-fed DIO rats given sham surgery (Obese, n = 11) and (5) ad libitum chow-fed rats given sham surgery (Lean, n = 12). Compared with Lean controls, food-restricted rats exhibited elevated morning (nadir) non-stress plasma corticosterone concentration and increased hypothalamic corticotropin-releasing hormone and vasopressin mRNA expression, indicative of basal HPA activation. This was largely prevented when weight loss was achieved by bariatric surgery. DIO increased HPA activation by acute (novel environment) stress and this was diminished by bariatric surgery-, but not pair-feeding-, induced weight loss. These results indicate that the HPA axis is differentially affected by weight loss from caloric restriction versus bariatric surgery, and this may contribute to the differing long-term effectiveness of these two weight-loss approaches.

Cortisol responses to a group public speaking task for adolescents: variations by age, gender, and race

Laboratory social stress tests involving public speaking challenges are widely used for eliciting an acute stress response in older children, adolescents, and adults. Recently, a group protocol for a social stress test (the Trier Social Stress Test for Groups, TSST-G) was shown to be effective in adults and is dramatically less time-consuming and resource-intensive compared to the single-subject version of the task. The present study sought to test the feasibility and effectiveness of an adapted group public speaking task conducted with a racially diverse, urban sample of U.S. adolescents (N=191; 52.4% female) between the ages of 11 and 18 (M=14.4 years, SD=1.93). Analyses revealed that this Group Public Speaking Task for Adolescents (GPST-A) provoked a significant increase in cortisol production (on average, approximately 60% above baseline) and in self-reported negative affect, while at the same time avoiding excessive stress responses that would raise ethical concerns or provoke substantial participant attrition. Approximately 63.4% of participants exhibited an increase in cortisol levels in response to the task, with 59.2% of the total sample showing a 10% or greater increase from baseline. Results also suggested that groups of five adolescents might be ideal for achieving more uniform cortisol responses across various serial positions for speech delivery. Basal cortisol levels increased with age and participants belonging to U.S. national minorities tended to have either lower basal cortisol or diminished cortisol reactivity compared to non-Hispanic Whites. This protocol facilitates the recruitment of larger sample sizes compared to prior research and may show great utility in answering new questions about adolescent stress reactivity and development.

Chewing after stress: psychosocial stress influences chewing frequency, chewing efficacy, and appetite

BACKGROUND

Psychosocial stress is accompanied by an increase in the activity of the hypothalamic-pituitary-adrenocortical (HPA)-axis and by an increase in food intake. At present, no studies have been conducted to examine the impact of a potent laboratory stress test on the chewing frequency.

METHODS

Thirty-one healthy participants (14 females, mean age 27.13) were compared after they had fulfilled the protocol of a standardized psychosocial stress test, the Trier Social Stress Test (TSST), and after a resting condition of silent reading in reference to their chewing frequency, chewing efficacy, food intake, and eating preferences. As part of the design free salivary cortisol levels and heart rate variability were measured repeatedly before and after the TSST and the resting condition.

RESULTS

After the TSST, the participants exhibited a significantly higher mean chewing frequency than after the resting condition (F(2,60)=3.600, p=.035, η(2)=.107). The testing condition had no influence on the amount of food intake. Following the psychosocial stress, however, the participants reported a significantly less general appetite (Z=-3.921, p<.001) and less of an appetite for eggs (Z=-2.023, p=.043) than after their resting condition. No correlation was found between the salivary cortisol response and the chewing frequency.

CONCLUSION

The results indicated that psychosocial stress is associated with an increase in chewing frequency, as measured with a sound-based apparatus, and with a decrease in appetite.

Low-income women's conceptualizations of emotional- and stress-eating

Emotional- and stress-eating have been proposed as risk factors for obesity. However, the way that individuals conceptualize these behaviors is not well understood and no studies have employed a qualitative approach. We sought to understand how women conceptualize emotional- and stress-eating. Sixty-one low-income women from South-central Michigan with young children (ages 2-5 years) participated in either a focus group or individual semi-structured interview during which they were asked about their conceptualizations of eating behaviors among adults and children. Responses were transcribed and the constant comparative method was used to identify themes. Identified themes included that emotional- and stress-eating are viewed as uncommon, severe, pitiable behaviors that reflect a lack of self-control and are highly stigmatized; that when these behaviors occurred among children, the behaviors resulted from neglect or even abuse; and that bored-eating is viewed as distinct from emotional- or stress-eating and is a common and humorous behavior with which participants readily self-identified. Future research and interventions should seek to develop more detailed conceptualizations of these behaviors to improve measurement, destigmatize emotional- and stress-eating and potentially capitalize on the strong identification with bored-eating by targeting this behavior for interventions.

Neuroendocrine circuits governing energy balance and stress regulation: functional overlap and therapeutic implications

Significant comorbidities between obesity-related metabolic disease and stress-related psychological disorders suggest important functional interactions between energy balance and brain stress integration. Largely overlapping neural circuits control these systems, and this anatomical arrangement optimizes opportunities for mutual influence. Here we first review the current literature identifying effects of metabolic neuroendocrine signals on stress regulation, and vice versa. Next, the contributions of reward-driven food intake to these metabolic and stress interactions are discussed. Lastly, we consider the interrelationships between metabolism, stress, and reward in light of their important implications in the development of therapies for metabolism- or stress-related disease.

Loss of melanocortin-4 receptor function attenuates HPA responses to psychological stress

The melanocortin 4 receptor (MC4R), well-known for its role in the regulation of energy balance, is widely expressed in stress-regulatory brain regions, including the paraventricular nucleus of the hypothalamus (PVH) and the medial amygdala (MeA). In agreement with this, MC4R has been implicated in hypothalamic-pituitary-adrenocortical axis (HPA) regulation. The present work investigated the role of chronic Mc4r function to modulate basal HPA axis tone and to facilitate acute HPA responses to psychological stress, using a novel rat model with Mc4r loss-of-function. In this study, adult male rats were placed into 3 groups (n=15/group) according to genotype [wild-type (WT); heterozygous mutant (HET); and homozygous mutant (HOM)]. Basal (pre-stress) plasma adrenocorticotropic hormone (ACTH) and corticosterone were measured in the AM and PM, and the HPA axis response to restraint was assessed in the AM. Rats were perfused at 2h after restraint to assess the effect of loss of MC4R on stress-induced c-Fos immunolabeling in stress-regulatory brain regions. We find that basal (non-stress) AM and PM plasma ACTH and corticosterone showed a normal diurnal rhythm that was not altered according to genotype. Consistent with this, adrenal and thymus weights were unaffected by genotype. However, the plasma ACTH and corticosterone responses to restraint were significantly reduced by loss of MC4R function. Likewise, stress-induced c-Fos immunolabeling in both PVH and MeA was significantly reduced by loss of Mc4r function. These results support the hypothesis that endogenous MC4R signaling contributes to the HPA axis response to stress. Because MC4R plays a critical role in the regulation of energy balance, the present work suggests that it may also serve as an important communication link between brain metabolic and stress systems.

Biological and psychological markers of stress in humans: focus on the Trier Social Stress Test

Validated biological and psychological markers of acute stress in humans are an important tool in translational research. The Trier Social Stress Test (TSST), involving public interview and mental arithmetic performance, is among the most popular methods of inducing acute stress in experimental settings, and reliably increases hypothalamic-pituitary-adrenal axis activation. However, although much research has focused on HPA axis activity, the TSST also affects the sympathetic-adrenal-medullary system, the immune system, cardiovascular outputs, gastric function and cognition. We critically assess the utility of different biological and psychological markers, with guidance for future research, and discuss factors which can moderate TSST effects. We outline the effects of the TSST in stress-related disorders, and if these responses can be abrogated by pharmacological and psychological treatments. Modified TSST protocols are discussed, and the TSST is compared to alternative methods of inducing acute stress. Our analysis suggests that multiple readouts are necessary to derive maximum information; this strategy will enhance our understanding of the psychobiology of stress and provide the means to assess novel therapeutic agents.

Blunted cortisol response to stress is associated with higher body mass index in low-income preschool-aged children

No known studies have tested the hypothesis that a blunted pattern of cortisol reactivity to stress, which is often found following exposure to chronic life stressors, is associated with a higher body mass index (BMI) in very young children. Low-income children (n=218, mean age 56.6 (range: 38.1-78.5; SD 7.0) months, 49.1% male, 56.4% white, 16.1% black, 11.5% Hispanic/Latino) participated in a series of behavioral tasks designed to elicit stress. Cortisol was sampled in saliva 5 times during the protocol, and area under the curve (AUC), representing total cortisol output during stress elicitation, was calculated. Children were weighed and height measured and body mass index (BMI) z-score was calculated. Linear regression was used to evaluate the association between cortisol AUC and BMI z-score, controlling for child age, sex, and race/ethnicity (non-Hispanic white vs. not); primary caregiver weight status (overweight, defined as BMI ≥ 25 vs. not); and family income-to-needs ratio. Mean child BMI z-score was 0.88 (SD=1.03). Mean cortisol AUC was 6.11 μg/dL/min (SD=10.44). In the fully adjusted model, for each 1-standard deviation unit decrease in cortisol AUC, the child's BMI z-score increased by 0.17 (SE 0.07) standard deviation units (p<0.02). A blunted cortisol response to stress, as is often seen following chronic stress exposure, is associated with increased BMI z-score in very young children. Further work is needed to understand how associations between stress, cortisol, and elevated body mass index may develop very early in the lifespan.

Genetics of food intake self-regulation in childhood: literature review and research opportunities

Pediatric obesity results from a daily energy imbalance between intake and expenditure, an imbalance potentially as slight as ~30-50 kcal/day (e.g., a few extra sips of cola or bites of a cookie). That an 'energy gap' so small may be so powerful suggests the importance of understanding mechanisms of food intake self-regulation (FISR). This review focuses on 4 behavioral indices of FISR in childhood: (1) eating in the absence of hunger; (2) eating rate; (3) caloric compensation and satiety responsiveness, and (4) food responsiveness. Evidence from pediatric samples around the world indicates that these traits are associated with body mass index, are heritable, and are linked to polymorphisms in the FTO gene. We review these data, also discussing their relevance to practical issues of parental feeding styles, portion sizes, and health literacy and numeracy. Research gaps and opportunities for future investigation are discussed. Multidisciplinary approaches and study designs that can address gene-environment interactions are needed to advance the science of FISR and stimulate new avenues for childhood obesity prevention.