Preliminary evidence of cognitive and brain abnormalities in uncomplicated adolescent obesity

Evaluation of executive functions in children and adolescents with obesity

The purpose of this study is to evaluation of executive functions of obese children and adolescents. Thirty children and adolescents with obesity between the ages of 11 and 18 and thirty age- and sex-matched healthy weight-peers were included. Participants with a body mass index (BMI) value of 5 to 85thpercentile and >95thpercentile were classified as normal and obese, respectively. Turkish Version of Kiddy Schedule for Affective Disorders and Schizophrenia-Present and Lifetime Version (K-SADS-PL-T) was applied for excluding participants with psychiatric diagnoses. All children and their parents were asked to fill out Strengths and Difficulties Questionnaire (SDQ), Wisconsin Card Sorting Test (WCST), and Stroop Color and Word Test (SCWT) to evaluate executive functions. Children with obesity tended to complete Part 4 and Part 5 of SCWT in longer time (p = 0.043 and p = 0.018, respectively). Rate of obesity was higher among nuclear family members (p = 0.001) with a higher number of relatives positive for history of a psychiatric disorder (p = 0.020). While children with obesity reported higher rates of peer problems as measured by SDQ (p = 0.030), there was no significant difference in parent forms. In conclusion, although children with obesity may have disruptions in their executive functions to some degree, this does not refer a generalized impairment.

The interconnection between obesity and executive function in adolescence: The role of the gut microbiome

In the United States, adolescent obesity is a growing epidemic associated with maladaptive executive functioning. Likewise, data link the microbiome to obesity. Emerging microbiome research has demonstrated an interconnection between the gut microbiome and the brain, indicating a bidirectional communication system within the gut-microbiome-brain axis in the pathophysiology of obesity. This narrative review identifies and summarizes relevant research connecting adolescent obesity as it relates to three core domains of executive functioning and the contribution of the gut microbiome in the relationship between obesity and executive functions in adolescence. The review suggests that (1) the interconnection between obesity, executive function, and the gut microbiome is a bidirectional connection, and (2) the gut microbiome may mediate the neurobiological pathways between obesity and executive function deficits. The findings of this review provide valuable insights into obesity-associated executive function deficits and elucidate the possible mediation role of the gut microbiome.

Neuroprotection in metabolic syndrome by environmental enrichment. A lifespan perspective

Metabolic syndrome (MetS) is defined by the concurrence of different metabolic conditions: obesity, hypertension, dyslipidemia, and hyperglycemia. Its incidence has been increasingly rising over the past decades and has become a global health problem. MetS has deleterious consequences on the central nervous system (CNS) and neurological development. MetS can last several years or be lifelong, affecting the CNS in different ways and treatments can help manage condition, though there is no known cure. The early childhood years are extremely important in neurodevelopment, which extends beyond, encompassing a lifetime. Neuroplastic changes take place all life through - childhood, adolescence, adulthood, and old age - are highly sensitive to environmental input. Environmental factors have an important role in the etiopathogenesis and treatment of MetS, so environmental enrichment (EE) stands as a promising non-invasive therapeutic approach. While the EE paradigm has been designed for animal housing, its principles can be and actually are applied in cognitive, sensory, social, and physical stimulation programs for humans. Here, we briefly review the central milestones in neurodevelopment at each life stage, along with the research studies carried out on how MetS affects neurodevelopment at each life stage and the contributions that EE models can provide to improve health over the lifespan.

Paediatric obesity and metabolic syndrome associations with cognition and the brain in youth: Current evidence and future directions

Obesity and components of the metabolic syndrome (MetS) are associated with differences in brain structure and function and in general and food-related cognition in adults. Here, we review evidence for similar phenomena in children and adolescents, with a focus on the implications of extant research for possible underlying mechanisms and potential interventions for obesity and MetS in youth. Current evidence is limited by a relative reliance on small cross-sectional studies. However, we find that youth with obesity and MetS or MetS components show differences in brain structure, including alterations in grey matter volume and cortical thickness across brain regions subserving reward, cognitive control and other functions, as well as in white matter integrity and volume. Children with obesity and MetS components also show some evidence for hyperresponsivity of food reward regions and hyporesponsivity of cognitive control circuits during food-related tasks, altered brain responses to food tastes, and altered resting-state connectivity including between cognitive control and reward processing networks. Potential mechanisms for these findings include neuroinflammation, impaired vascular reactivity, and effects of diet and obesity on myelination and dopamine function. Future observational research using longitudinal measures, improved sampling strategies and study designs, and rigorous statistical methods, promises to further illuminate dynamic relationships and causal mechanisms. Intervention studies targeted at modifiable biological and behavioural factors associated with paediatric obesity and MetS can further inform mechanisms, as well as test whether brain and behaviour can be altered for beneficial outcomes.

Obesity is associated with decreased gray matter volume in children: a longitudinal study

Childhood obesity has become a global health problem. Previous studies showed that childhood obesity is associated with brain structural differences relative to controls. However, few studies have been performed with longitudinal evaluations of brain structural developmental trajectories in childhood obesity. We employed voxel-based morphometry (VBM) analysis to assess gray matter (GM) volume at baseline and 2-year follow-up in 258 obese children (OB) and 265 normal weight children (NW), recruited as part of the National Institutes of Health Adolescent Brain and Cognitive Development study. Significant group × time effects on GM volume were observed in the prefrontal lobe, thalamus, right precentral gyrus, caudate, and parahippocampal gyrus/amygdala. OB compared with NW had greater reductions in GM volume in these regions over the 2-year period. Body mass index (BMI) was negatively correlated with GM volume in prefrontal lobe and with matrix reasoning ability at baseline and 2-year follow-up. In OB, Picture Test was positively correlated with GM volume in the left orbital region of the inferior frontal gyrus (OFCinf_L) at baseline and was negatively correlated with reductions in OFCinf_L volume (2-year follow-up vs. baseline). These findings indicate that childhood obesity is associated with GM volume reduction in regions involved with reward evaluation, executive function, and cognitive performance.

Altered brain activation in uncomplicated pediatric obesity: The second moment is more sensitive than the first

Traditionally, studies of the neurocognitive correlates of obesity have computed a central tendency across trials of a task to estimate the functional abilities of individual members of obese and non-obese groups. This computation assumes that the correlate is stable over time-a questionable assumption when individuals are impulsive, periodically inattentive, and capable of overcompensation following awareness of failure. The present investigation departs from the tradition by focusing on the second moment, or variability, in brain activation during a simple selective attention task. It compared 124 non-obese and 80 obese teenaged girls on the across-trial average amplitude and inter-trial variability (ITV) of a sensitive biomarker of attention, the P300 event-related electroencephalographic potential. It found that P300 ITV outperformed P300 average amplitude in differentiating the groups. Further, it found that the elevated P300 ITV among obese teenagers was associated with other indicators of impulsivity and inattention as well as slower reaction times and a trend toward more variable reaction times. Future studies should investigate the value of P300 ITV as an objective and sensitive endpoint for cognitive training focused on improving the attention skills of obese children.

Impact of dysglycemia and obesity on the brain in adolescents with and without type 2 diabetes: A pilot study

OBJECTIVE

Both diabetes and obesity can affect the brain, yet their impact is not well characterized in children with type 2 (T2) diabetes and obesity. This pilot study aims to explore differences in brain function and cognition in adolescents with T2 diabetes and obesity and nondiabetic controls with obesity and lean controls.

RESEARCH DESIGN AND METHODS

Participants were 12-17 years old (5 T2 diabetes with obesity [mean HgbA1C 10.9%], 6 nondiabetic controls with obesity and 10 lean controls). Functional MRI (FMRI) during hyperglycemic/euglycemic clamps was performed in the T2 diabetes group.

RESULTS

When children with obesity, with and without diabetes, were grouped (mean BMI 98.8%), cognitive scores were lower than lean controls (BMI 58.4%) on verbal, full scale, and performance IQ, visual-spatial and executive function tests. Lower scores correlated with adiposity and insulin resistance but not HgbA1C. No significant brain activation differences during task based and resting state FMRI were noted between children with obesity (with or without diabetes) and lean controls, but a notable effect size for the visual-spatial working memory task and resting state was observed.

CONCLUSIONS

In conclusion, our pilot study suggests that obesity, insulin resistance, and dysglycemia may contribute to relatively poorer cognitive function in adolescents with T2 diabetes and obesity. Further studies with larger sample size are needed to assess if cognitive decline in children with obesity, with and without T2 diabetes, can be prevented or reversed.

Gray matter reduction in bilateral insula mediating adverse psychiatric effects of body mass index in schizophrenia

BACKGROUND

Both schizophrenia (SZ) and overweight/obesity (OWB) have shown some structural alterations in similar brain regions. As higher body mass index (BMI) often contributes to worse psychiatric outcomes in SZ, this study was designed to examine the effects of OWB on gray matter volume (GMV) in patients with SZ.

METHODS

Two hundred fifty subjects were included and stratified into four groups (n = 69, SZ patients with OWB, SZ-OWB; n = 74, SZ patients with normal weight, SZ-NW; n = 54, healthy controls with OWB, HC-OWB; and n = 53, HC with NW, HC-NW). All participants were scanned using high-resolution T1-weighted sequence. The whole-brain voxel-based morphometry was applied to examine the GMV alterations, and a 2 × 2 full factorial analysis of variance was performed to identify the main effects of diagnosis (SZ vs HC), BMI (NW vs OWB) factors, and their interactions. Further, the post hoc analysis was conducted to compare the pairwise differences in GMV alterations.

RESULTS

The main effects of diagnosis were located in right hippocampus, bilateral insula, rectus, median cingulate/paracingulate gyri and thalamus (SZ < HC); while the main effects of BMI were displayed in right amygdala, left hippocampus, bilateral insula, left lingual gyrus, and right superior temporal gyrus (OWB < NW). There were no significant diagnosis-by-BMI interaction effects in the present study, but the results showed that both SZ and OWB were additively associated with lower GMV in bilateral insula. Moreover, mediation analyses revealed the indirect effect of BMI on negative symptom via GMV reduction in bilateral insula.

CONCLUSION

This study further supports that higher BMI is associated with lower GMV, which may increase the risk of unfavourable disease courses in SZ.

Endophenotypic correlates of cognitive function in reproductive-age individuals with polycystic ovary syndrome

Objective

To characterize cognitive performance in relation to hormonal and metabolic factors in women with polycystic ovary syndrome (PCOS).

Design

Cross-sectional study.

Setting

Tertiary university center.

Patients

A total of 48 individuals, aged 21-46 years, with PCOS according to the Rotterdam criteria.

Interventions

Complete history and physical examinations, endovaginal ultrasounds, dermatologic assessments, neuropsychological assessments, and metabolic and hormonal serum tests.

Main Outcome Measures

Sample-based z-scores on a comprehensive cognitive test battery.

Results

Subjects were defined as having an androgenic (n = 31) or a nonandrogenic (n = 17) PCOS phenotype. Compared with their nonandrogenized counterparts, subjects with hyperandrogenism demonstrated lower relative performance on the tests of executive function (β-coefficient for the executive function composite z-score, -0.44; 95% confidence interval, -0.79 to -0.09), despite similar performance on the tests of memory, verbal reasoning, and perceptual reasoning. These differences were independent of age, years of education, and obesity. In an exploratory analysis in which subjects were stratified by the presence of insulin resistance (IR), subjects with PCOS with both IR and hyperandrogenism showed the lowest performance on a composite score of executive function, followed by those with hyperandrogenism alone.

Conclusions

In this small study, subjects with hyperandrogenic PCOS demonstrated lower performance on the tests of executive function than subjects with nonandrogenic PCOS. Additional research is needed to confirm these findings in larger cohorts and investigate the role of modifiable factors, including IR, on cognitive outcomes.

Context Matters: Preliminary Evidence That the Association between Positive Affect and Adiposity in Infancy Varies in Social vs. Non-Social Situations

Previous studies have suggested that infants high in negative affect have higher levels of adiposity, arising in part via changes in nutrition (e.g., “feeding to soothe”). Few studies have examined whether positive affect shows similar or inverse associations with adiposity. The current study examined cross-sectional and longitudinal relationships between adiposity and observations of positive affect in both a social and a non-social context, using data from infants at four (n = 125) and 12 (n = 80) months of age. Our analyses did not find any cross-sectional associations between positive affect and adiposity (all p > 0.05). However, in the longitudinal analyses, positive affect in a non-social context, when observed at four months of age, was positively associated with weight-for-length at 12 months of age (zWFL; ß = 1.49, SE = 0.67, p = 0.03), while positive affect observed at four months of age in a social context was inversely associated with body fat percentage at 12 months of age (ß = −11.41, SE = 5.44, p = 0.04). These findings provide preliminary evidence that the p positive affect is related to adiposity in infancy and suggest that the direction of association (i.e., direct or inverse) may be specific to the context in which positive affect is measured. Future research should examine the role of nutritional status in any relationships between adiposity and emotion at this early stage.

Anthropometric Parameters, Physical Activity, Physical Fitness, and Executive Functions among Primary School Children

Physical activity during childhood and adolescence favors brain development and cognitive functioning, particularly the executive functions. This study aimed to assess potential associations between anthropometric parameters, physical activity, physical fitness, and executive functions among elementary school children returning to school after the COVID-19 lockdown in Chile. School-age male and female participants (n = 90; age, 10−12 years) participated in the study. To determine the association between variables, a multivariable linear regression analysis was performed. Higher fat-related anthropometric indexes were associated with lower working memory, cognitive flexibility, planning, and attention (r = −0.55 to −0.22; p = 0.031 to <0.001). In contrast, higher physical activity levels, better sprint performance, higher lower-body muscular power, and greater upper-body muscular strength were associated with better working memory, cognitive flexibility, inhibition, planning, and/or attention (r = 0.19 to −0.54; p = 0.04 to <0.001). Current results consistently suggest the need for adequate levels of physical activity, physical fitness, and anthropometric parameters among the school-age population to promote healthy and adequate executive functions.

A systematic review of diffusion tensor imaging studies in obesity

Obesity is a major global health problem leading to serious complications. It has been consistently associated with alterations in brain structure. Diffusion tensor imaging is used to examine brain white matter microstructure by assessing the dynamics of water diffusion in white matter tracts. Fractional anisotropy and mean diffusivity are two parameters measuring the directionality and rate of diffusion, respectively. Changes in these indices associated with obesity have been previously reported in numerous fiber tracts. This systematic review investigates microstructural white matter alterations in obesity using diffusion tensor imaging. A computerized search was performed in PubMed, Web of Science, and Livivo databases. Based on the inclusion/exclusion criteria, 31 cross-sectional studies comparing individuals with obesity and lean controls were identified. The studies included mixed-gender samples of children, young, middle-aged, and older adults. The majority of included studies reported decreased fractional anisotropy and increased mean diffusivity associated with elevated body mass index, suggesting white matter abnormalities. Nevertheless, a pattern of alterations is inconsistent across studies. This could be explained by several potential biases assessed by the National Institute of Health quality assessment tool. Furthermore, a direct assessment of body fat is recommended for a more accurate characterization of the brain-body relationship.

Milk fat globule membrane attenuates high fat diet-induced neuropathological changes in obese Ldlr-/-.Leiden mice

BACKGROUND

Milk-fat globule membrane (MFGM) is a complex structure secreted by the mammary gland and present in mammalian milk. MFGM contains lipids and glycoproteins as well as gangliosides, which may be involved in myelination processes. Notably, myelination and thereby white matter integrity are often altered in obesity. Furthermore, MFGM interventions showed beneficial effects in obesity by affecting inflammatory processes and the microbiome. In this study, we investigated the impact of a dietary MFGM intervention on fat storage, neuroinflammatory processes and myelination in a rodent model of high fat diet (HFD)-induced obesity.

METHODS

12-week-old male low density lipoprotein receptor-deficient Leiden mice were exposed to a HFD, a HFD enriched with 3% whey protein lipid concentrate (WPC) high in MFGM components, or a low fat diet. The impact of MFGM supplementation during 24-weeks of HFD-feeding was examined over time by analyzing body weight and fat storage, assessing cognitive tasks and MRI scanning, analyzing myelinization with polarized light imaging and examining neuroinflammation using immunohistochemistry.

RESULTS

We found in this study that 24 weeks of HFD-feeding induced excessive fat storage, increased systolic blood pressure, altered white matter integrity, decreased functional connectivity, induced neuroinflammation and impaired spatial memory. Notably, supplementation with 3% WPC high in MFGM components restored HFD-induced neuroinflammation and attenuated the reduction in hippocampal-dependent spatial memory and hippocampal functional connectivity.

CONCLUSIONS

We showed that supplementation with WPC high in MFGM components beneficially contributed to hippocampal-dependent spatial memory, functional connectivity in the hippocampus and anti-inflammatory processes in HFD-induced obesity in rodents. Current knowledge regarding exact biological mechanisms underlying these effects should be addressed in future studies.

Memory and eating: A bidirectional relationship implicated in obesity

This paper reviews evidence demonstrating a bidirectional relationship between memory and eating in humans and rodents. In humans, amnesia is associated with impaired processing of hunger and satiety cues, disrupted memory of recent meals, and overconsumption. In healthy participants, meal-related memory limits subsequent ingestive behavior and obesity is associated with impaired memory and disturbances in the hippocampus. Evidence from rodents suggests that dorsal hippocampal neural activity contributes to the ability of meal-related memory to control future intake, that endocrine and neuropeptide systems act in the ventral hippocampus to provide cues regarding energy status and regulate learned aspects of eating, and that consumption of hypercaloric diets and obesity disrupt these processes. Collectively, this evidence indicates that diet-induced obesity may be caused and/or maintained, at least in part, by a vicious cycle wherein excess intake disrupts hippocampal functioning, which further increases intake. This perspective may advance our understanding of how the brain controls eating, the neural mechanisms that contribute to eating-related disorders, and identify how to treat diet-induced obesity.

Choices of (in)action in obesity: Implications for research on treatment and prevention

The obesity epidemic has crossed social-demographic barriers and is a matter of significant concern. Why do individuals fail to restrain from eating high-calorie foods and fail to follow treatment routines that reduce the risk of health complications? These questions have been addressed through behavioral and brain imaging studies on prefrontal cortex inhibitory mechanisms. Failure to inhibit undesirable behaviors has become a hallmark of obesity. In many life situations, obesity risk is increased by inaction (e.g., not taking blood pressure medication, not following a healthy diet). Risk by inaction has been defined as passive risk-taking, and it is correlated with traits such as procrastination, future time perspective, and cognitive avoidance. To the present, passive tendencies, specifically in the context of risk-taking behaviors, have not been addressed in the obesity literature. We introduce a framework in which active and passive risk-taking behaviors are integrated within the scope of bidirectional models of obesity that describe the brain as both the cause and the consequence of obesity vulnerability. The present perspective aims to foster new research on treatment and prevention, and also on the neurobiology of passive behaviors in obesity and other metabolic conditions.

Does obesity-associated insulin resistance affect brain structure and function of adolescents differentially by sex?

Metabolic abnormalities affect the adolescent brain. For equivalent abnormalities in metabolism young people exhibit deficits in more cognitive domains than adults. We examine sex differences performance for adolescents with obesity/insulin resistance (IR) and evaluated how sex and IR effected frontal lobe structures and executive functioning. 125 adolescents underwent medical, cognitive, and brain-imaging assessments. Participants were categorized as insulin sensitive (IS) (QUICKI ≥ 0.350) or IR (QUICKI < 0.350). Degree of IR may affect brain and cognition differentially by sex. Females had positive associations between QUICKI and anterior cingulate cortex (ACC) volume, medial orbito-frontal cortex (OFC) thickness, and scores on the Stroop and Digit Symbol Substitution (DSST) tests. Females with IR tended to have thinner insular cortices. No such associations were found in males. In female adolescents, IR may negatively affect brain structure and function. No such effects were found for males. Although needing more development, hormonal effects and inflammation are potential contributors.

Aerobic Fitness, B-Vitamins, and Weight Status Are Related to Selective Attention in Children

There is an increasing prevalence of poor health behaviors during childhood, particularly in terms of physical activity and nutrition. This trend has occurred alongside a growing body of evidence linking these behaviors to cognitive function. B-vitamins are thought to be particularly important in the neural development that occurs during pregnancy, as well as in healthy cognitive aging. However, much less is known regarding the role of B-vitamins during childhood. Given that preadolescent childhood is a critical period for cognitive development, this study investigated the relationship between specific aspects of nutrition, particularly B-vitamins, and related health factors (e.g., body mass, fitness) on selective attention in children. Children (n = 85; 8-11 years) completed a selective attention task to assess inhibition. Participant's dietary intake was collected using the Automated Self-Administered 24-h dietary assessment tool. Correlations between specific nutrients, BMI, fitness, and task performance were investigated. After accounting for demographic variables and total caloric intake, increased B-vitamin intake (i.e., thiamin and folic acid) was associated with shorter reaction times (p's < 0.05), fitness was associated with greater response accuracy (p < 0.05), and increased BMI was related to increased variability in reaction times (p < 0.05). Together, these findings suggest that aspects of health may have unique contributions on cognitive performance. Proper physical health and nutrition are imperative for effective cognitive functioning in preadolescent children. Targeted efforts aimed at health education amongst this population could ensure proper cognitive development during school-age years, providing a strong foundation throughout life.

Sex Differences in the Association between Different Obesity Parameters and Cognitive Function in Older Adults: A Cross-Sectional Study in Rural China

BACKGROUND

Early identification of risk factors for cognition decline may contribute to the interventions for Alzheimer's disease. Obesity is a common modifiable risk factor for chronic diseases. The association between obesity and cognition in older adults is limited, and sex differences in this area have not been well recognized.

OBJECTIVE

The aim of the study was to observe the sex differences in the relationship between obesity and cognition in a rural community-dwelling older population of Guizhou, China.

METHODS

Data were gathered from the baseline survey of a cohort study of older people in rural areas of Guizhou, China. Demographic and behavioral data (sex, age, education, household income, smoking history, drinking history, history of head injury, diet, and level of physical exercise time) were collected. The Mini-Mental State Examination (MMSE) was used to assess cognitive function. Body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist-to-hip ratio (WHR) were used as different measures of obesity. Comparisons between the groups were made by the Wilcoxon rank-sum test or Kruskal-Wallis H test. Restricted cubic spline regression was used to examine a dose-response relationship between obesity indicators and cognitive function. Linear relationships were performed by the multivariable linear regression model.

RESULTS

A total of 1,654 participants including 964 women and 690 men were enrolled in this study. After adjustment, BMI showed a nonlinear relationship with MMSE scores in women. There was a significant trend toward increasing MMSE scores at the low end of BMI (13.52-20.10 kg/m2, p = 0.014). The multivariable linear regression model showed that MMSE increased by 0.631 (p < 0.001) for every one standard deviation increase in HC in women. No association was found between obesity parameters and cognitive function in men.

CONCLUSION

Our results suggest that there are significant sex differences in some obesity parameters and cognition in an older Chinese population. BMI and HC are positively associated with cognitive function in women. No association was found between obesity measures and cognitive function in men.

Body fat, cardiovascular risk factors and brain structure in school-age children

BACKGROUND

In adults, cardiovascular risk factors are known to be associated with brain health. We hypothesized that these associations are already present at school-age. We examined the associations of adverse body fat measures and cardiovascular risk factors with brain structure, including volumetric measures and white matter microstructure, in 10-year-old children.

METHODS

We performed a cross-sectional analysis in a population-based prospective cohort study in Rotterdam, the Netherlands. Analyses were based on 3098 children aged 10 years with neuroimaging data and at least one measurement of body fat and cardiovascular risk factors. Body fat measures included body mass index (BMI), fat mass index and android fat mass percentage obtained by Dual-energy X-ray absorptiometry. Cardiovascular risk factors included blood pressure, and serum glucose, insulin and lipids blood concentrations. Structural neuroimaging, including global and regional brain volumes, was quantified by magnetic resonance imaging. DTI was used to assess white matter microstructure, including global fractional anisotropy (FA) and mean diffusivity (MD).

RESULTS

As compared to children with a normal weight, those with underweight had a smaller total brain and white matter volumes (differences -18.10 (95% Confidence Interval (CI) -30.97,-5.22) cm³, -10.64 (95% CI -16.82,-4.47) cm³, respectively). In contrast, one SDS (Standard Deviation Score) increase in fat mass index was associated with a smaller gray matter volume (differences -3.48 (95% CI -16.82, -4.47) cm³). Also, one SDS increase in android fat mass percentage was associated with lower white matter diffusivity (difference -0.06 (95% CI -0.10, -0.02) SDS). None of the other cardiovascular risk factors were associated with any of the brain outcomes.

CONCLUSIONS

Body fat measures, but not other cardiovascular risk factors, were associated with structural neuroimaging outcomes in school-aged children. Prospective studies are needed to assess causality, direction and long-term consequences of the associations.

Effects of severe obesity and sleeve gastrectomy on cortical thickness in adolescents

OBJECTIVE

Neurocognitive differences in pediatric obesity may be underpinned by cortical structural alterations. Differences in cortical thickness associated with severe obesity were examined, and preliminary evidence was sought for changes following vertical sleeve gastrectomy (VSG).

METHODS

A total of 18 adolescents with severe obesity (OB) and 17 without obesity (nOB), aged 14 to 21, underwent T1-weighted structural magnetic resonance imaging. A subset was scanned twice 5 months apart to compare cortical thickness following VSG (n = 6) with two control groups: wait-listed (n = 9) and nOB (n = 12).

RESULTS

At baseline, OB had a thinner cortex than nOB in motor and superior parietal cortices. At follow-up, VSG adolescents lost weight, the wait-listed group gained weight, and nOB did not change. Group × Time interactions indicated that VSG had cortical thinning in orbitofrontal, primary sensorimotor, superior, and middle temporal cortices and thickening in lingual, fusiform, and lateral occipital cortices. Wait-listed and nOB groups largely did not change.

CONCLUSIONS

Severe obesity is associated with a thinner cortex in motor and attentional function-associated regions. VSG resulted in cortical thinning in reward valuation, sensory, and perceptual regions and thickening in visual regions. Surgery-related changes in regions distinct from those associated with obesity suggest compensation, rather than normalization. These results provide preliminary evidence supporting structural neural alterations following sleeve gastrectomy.

Childhood Obesity, Cortical Structure, and Executive Function in Healthy Children

The development of executive function is linked to maturation of prefrontal cortex (PFC) in childhood. Childhood obesity has been associated with changes in brain structure, particularly in PFC, as well as deficits in executive functions. We aimed to determine whether differences in cortical structure mediate the relationship between executive function and childhood obesity. We analyzed MR-derived measures of cortical thickness for 2700 children between the ages of 9 and 11 years, recruited as part of the NIH Adolescent Brain and Cognitive Development (ABCD) study. We related our findings to measures of executive function and body mass index (BMI). In our analysis, increased BMI was associated with significantly reduced mean cortical thickness, as well as specific bilateral reduced cortical thickness in prefrontal cortical regions. This relationship remained after accounting for age, sex, race, parental education, household income, birth-weight, and in-scanner motion. Increased BMI was also associated with lower executive function. Reduced thickness in the rostral medial and superior frontal cortex, the inferior frontal gyrus, and the lateral orbitofrontal cortex partially accounted for reductions in executive function. These results suggest that childhood obesity is associated with compromised executive function. This relationship may be partly explained by BMI-associated reduced cortical thickness in the PFC.

Obesity and Gray Matter Volume Assessed by Neuroimaging: A Systematic Review

Obesity has become a major public and individual health problem due to its high worldwide prevalence and its relation with comorbid conditions. According to previous studies, obesity is related to an increased risk of cognitive impairment and dementia. This systematic review aims to further examine the present state of the art about the association between obesity and gray matter volume (GMV) as assessed by magnetic resonance imaging (MRI). A search was conducted in Pubmed, SCOPUS and Cochrane of those studies released before 1 February 2021 including MRIs to assess the GMVs in obese participants. From this search, 1420 results were obtained, and 34 publications were finally included. Obesity was mainly measured by the body mass index, although other common types of evaluations were used (e.g., waist circumference, waist-to-hip ratio and plasma leptin levels). The selected neuroimaging analysis methods were voxel-based morphometry (VBM) and cortical thickness (CT), finding 21 and 13 publications, respectively. There were 30 cross-sectional and 2 prospective longitudinal studies, and 2 articles had both cross-sectional and longitudinal designs. Most studies showed a negative association between obesity and GMV. This would have important public health implications, as obesity prevention could avoid a potential risk of GMV reductions, cognitive impairment and dementia.

Child physical activity as a modifier of the relationship between prenatal exposure to maternal overweight/obesity and neurocognitive outcomes in offspring

BACKGROUND/OBJECTIVES

With rising obesity rates among pregnant women, more children are exposed in utero to maternal obesity. In prior epidemiological studies, exposure to maternal obesity was associated with lower intelligence quotient (IQ) scores and worse cognitive abilities in offspring. Further studies have shown that offspring exposed to maternal obesity, exhibit differences in the white matter microstructure properties, fractional anisotropy (FA) and mean diffusivity (MD). In contrast, physical activity was shown to improve cognition and white matter microstructure during childhood. We examined if child physical activity levels modify the relationship between prenatal exposure to maternal obesity with IQ and white matter microstructure in offspring.

SUBJECTS/METHODS

One hundred children (59% girls) age 7-11 years underwent brain magnetic resonance imaging and IQ testing. Maternal pre-pregnancy BMI was abstracted from electronic medical records. White matter was assessed using diffusion tensor imaging with the measures, global FA, MD. The 3-day physical activity recall was used to measure moderate-to-vigorous physical activity and vigorous physical activity (VPA). Linear regression was used to test for interactions between prenatal exposure to maternal overweight/obesity and child PA levels on child IQ and global FA/MD.

RESULTS

The relationship between prenatal exposure to maternal overweight/obesity and child IQ and global FA varied by child VPA levels. Children exposed to mothers with overweight/obesity who engaged in more VPA had higher IQ scores and global FA compared to exposed children who engaged in less VPA. Associations were independent of child age, sex, BMI Z-score and socioeconomic status. Children born to normal-weight mothers did not differ in either IQ or global FA by time in VPA.

CONCLUSIONS

Our findings support findings in rodent models and suggest that VPA during childhood modifies the relationship between prenatal exposure to maternal obesity and child IQ and white matter microstructure.

Metabolic syndrome and cognitive performance across the adult lifespan

Metabolic Syndrome (MetS) is associated with increased rates of mortality and increased risk for developing dementia. Changes in brain structure and cognitive functioning have been reported within the literature. However, research examining cognitive performance in individuals with MetS is limited, inconclusive, and focuses primarily on older cohorts. As such, the effect of MetS on cognitive functioning earlier in the lifespan is unclear. This study aimed to investigate cognitive performance in young, middle-aged, and older adults with multiple metabolic and vascular risk factors in a sample of community dwelling participants (N = 128). Participants were administered a comprehensive neuropsychological battery and self-report measures. As expected, older adults performed more poorly than young and middle-aged adults across most assessments. Relative to controls, individuals with MetS reported greater hunger and disinhibited eating. MetS participants performed more poorly on Color-Word Interference: Inhibition. Additionally, when weight was accounted for, there was a significant relationship between MetS and select executive functioning tasks in middle-aged adults. These findings suggest that aspects of executive functioning may be impaired in MetS and could be further impacted by excess weight in middle-age. Future studies aimed at investigating potential causal relationships between metabolic and vascular risk factors, disinhibited eating, and executive dysfunction may provide insight into effective intervention targets to prevent MetS.

Acute after-school screen time in children decreases impulse control and activation toward high-calorie food stimuli in brain regions related to reward and attention

The purpose of this study was to examine the effects of after-school sedentary screen time on children's brain activation in reward and cognitive control regions in response to pictures of high- and low-calorie foods. Thirty-two children participated in a randomized crossover study with counterbalanced treatment conditions. Conditions took place on separate days after school and included three hours of active or sedentary play. After each condition, neural activation was assessed using functional magnetic resonance imaging (fMRI) while participants completed a go/no-go task involving pictures of high- and low-calorie foods. General response inhibition was also measured using the Stroop task. Hunger was measured upon arrival to the testing facility and just prior to fMRI scans. Mixed effects models were used to evaluate main effects and interactions. Significant stimulus by condition interactions were found in the right superior parietal cortex, and left anterior cingulate cortex (Ps ≤ 0.05). High-calorie pictures elicited significantly more activation bilaterally in the orbitofrontal cortex compared to low-calorie pictures (Ps ≤ 0.05). Stroop task performance diminished significantly following the sedentary condition compared to the active (P ≤ 0.05). Subjective feelings of hunger were not different between conditions at any point. Sedentary screen time was associated with significantly decreased response inhibition and a reversed brain activation pattern to pictures of high- and low-calorie foods compared to active play, in areas of the brain important to the modulation of food intake. Decreased attention, and impulse control following sedentary screen time may contribute to disinhibited eating that can lead to overweight and obesity.

Psychopathology and Adolescent Bariatric Surgery: A Topical Review to Support Psychologists in Assessment and Treatment Considerations

The rising rates of severe obesity among adolescents in the United States indicate a dire need for more intensive weight management strategies. While current evidence suggests that bariatric surgery is a safe and efficacious intervention for adolescents, the linkages with psychopathology before and after surgery are not well understood. Psychologists are an integral part of the interdisciplinary surgery team and play an important role in preparing youth for bariatric surgery as well as supporting adolescents post-surgery. The present manuscript reviews the literature on psychopathology in the context of adolescent bariatric surgery, discusses consideration of psychopathology as a contraindication for surgery, and provides recommendations on how psychologist members of the bariatric surgery team may balance attention to motivation and adherence to medical recommendations with assessment and treatment of psychopathology. Finally, the importance of continued research to confirm clinical consensus regarding decision-making and expansion of psychological resources within adolescent bariatric surgery programs are discussed.

The effect of body mass index on hippocampal morphology and memory performance in late childhood and adolescence

Childhood obesity is associated with negative physiological and cognitive health outcomes. The hippocampus is a diverse subcortical structure involved in learned feeding behaviors and energy regulation, and research has shown that the hippocampus is vulnerable to the effects of excess adiposity. Previous studies have demonstrated reduced hippocampal volume in overweight and obese children; however, it is unclear if certain subregions are selectively affected. The purpose of this study was to determine how excess body weight influences regional hippocampal surface morphology and memory performance in a large cross-sectional cohort of 588 children and adolescents between 8.33 and 19.92 years of age using body mass index expressed as a percentage of the 95th percentile cutoff (%BMIp95). We demonstrate %BMIp95 is associated with reduced radial thickness in the superior anterior region of the left hippocampus, and this relationship is predominantly driven by children younger than 14 years. We also found %BMIp95 was associated with worse performance on a spatial episodic memory task and this relationship was partially mediated by the radial thickness of the significant shape cluster. These results demonstrate the differential influence of excess body weight on regional hippocampal structure and hippocampal-dependent behavior in children and adolescents.

Visual, Verbal and Everyday Memory 2 Years After Bariatric Surgery: Poorer Memory Performance at 1-Year Follow-Up

Severe obesity has been associated with reduced performance on tests of verbal memory in bariatric surgery candidates. There is also some evidence that bariatric surgery leads to improved verbal memory, yet these findings need further elucidation. Little is known regarding postoperative memory changes in the visual domain and how patients subjectively experience their everyday memory after surgery. The aim of the current study was to repeat and extend prior findings on postoperative memory by investigating visual, verbal, and self-reported everyday memory following surgery, and to examine whether weight loss and somatic comorbidity predict memory performance. The study was a prospective, observational study in which participants (n = 48) underwent cognitive testing at baseline, 1 and 2 years after bariatric surgery. Repeated measures analyses of variance revealed significantly poorer visual and verbal memory performance at the 1-year follow-up, with performance subsequently returning to baseline levels after 2 years. Verbal learning and self-reported everyday memory did not show significant postoperative changes. Memory performance at 1 year was not significantly predicted by weight loss, changes in C-reactive protein levels or postoperative somatic comorbidity (Type 2 diabetes, sleep apnea, and hypertension). The study demonstrated poorer visual and verbal memory performance at 1-year follow-up that returned to baseline levels after 2 years. These findings are in contrast to most previous studies and require further replication, however, the results indicate that postoperative memory improvements following bariatric surgery are not universal. Findings suggest that treatment providers should also be aware of patients potentially having poorer memory at 1 year following surgery.

Familial Obesity Risk and Current Excess Weight Influence Brain Structure in Adolescents

OBJECTIVE

Obesity risk transmits from parents to children. Underlying neural mechanisms were investigated in this study by evaluating influences of familial obesity risk defined by maternal obesity and influences of current overweight on three indices of brain structure in adolescents.

METHODS

In total, 22 lean adolescents with lean mothers (lean low-risk), 25 lean adolescents with mothers with obesity/overweight (lean high-risk), and 36 adolescents with obesity/overweight underwent structural MRI scans for estimation of regional gray and white matter volume and cortical thickness.

RESULTS

The lean high-risk compared with the lean low-risk group demonstrated lower gray and white matter volume and cortical thickness in the postcentral gyrus (somatosensory cortex), lower gray and white matter volume in the opercular cortex (taste cortex), lower gray matter volume and cortical thickness in the anterior cingulate cortex, and lower cortical thickness in the precuneus. Comparisons of the lean and obesity/overweight groups revealed further structural alterations in the postcentral gyrus, posterior cingulate gyrus, and middle temporal gyrus.

CONCLUSIONS

Familial obesity risk and current obesity/overweight were associated with overlapping and distinct patterns of brain structure alterations. Longitudinal studies are warranted to investigate whether structural changes associated with familial obesity risk predict future weight trajectories.

Volumetric brain magnetic resonance imaging analysis in children with obstructive sleep apnea

OBJECTIVES

Pediatric Obstructive Sleep Apnea (OSA) is associated with neurocognitive deficits. Cerebral structural alterations in the frontal cortex, cerebellum, and hippocampus have been reported in adult OSA patients. These brain areas are important for executive functioning, motor regulation of breathing, and memory function, respectively. Corresponding evidence comparing cerebral structures in pediatric OSA patients is limited. The objective of this study is to investigate MRI differences in cortical thickness and cortical volume in children with and without OSA.

STUDY DESIGN

Prospective, single institutional case-control study.

METHODS

Forty-five children were recruited at a pediatric tertiary care center (27 with OSA; mean age 9.9 ± 1.9 years, and 18 controls; mean age 10.5 ± 1.0 years). The OSA group underwent magnetic resonance imaging (MRI), polysomnography (PSG) and completed the Pediatric Daytime Sleepiness Scale (PDSS) and the Child's Sleep Habits Questionnaire (CSHQ). High-resolution T1-weighted MRI was utilized to examine cortical thickness and gray and white matter volume in children with OSA compared to a healthy group of demographically-comparable children without OSA selected from a pre-existing MRI dataset.

RESULTS

Children with OSA showed multiple regions of cortical thinning primarily in the left hemisphere. Reduced gray matter (GM) volume was noted in the OSA group in multiple frontal regions of the left hemisphere (superior frontal, rostral medial frontal, and caudal medial frontal regions). Reduced white matter (WM) volume in both the left and right hemisphere was observed in regions of the frontal, parietal, and occipital lobes in children with OSA.

CONCLUSION

This study noted differences in cortical thickness and GM and WM regional brain volumes in children with OSA. These findings are consistent with other pediatric studies, which also report differences between healthy children and those with OSA. We found that the severity of OSA does not correlate with the extent of MRI alterations.

Obesity and Brain Function: The Brain-Body Crosstalk

Dementia comprises a wide range of progressive and acquired neurocognitive disorders. Obesity, defined as excessive body fat tissue, is a common health issue world-wide and a risk factor for dementia. The adverse effects of obesity on the brain and the central nervous system have been the subject of considerable research. The aim of this review is to explore the available evidence in the field of body-brain crosstalk focusing on obesity and brain function, to identify the major research measurements and methodologies used in the field, to discuss the potential risk factors and biological mechanisms, and to identify the research gap as a precursor to systematic reviews and empirical studies in more focused topics related to the obesity-brain relationship. To conclude, obesity appears to be associated with reduced brain function. However, obesity is a complex health condition, while the human brain is the most complicated organ, so research in this area is difficult. Inconsistency in definitions and measurement techniques detract from the literature on brain-body relationships. Advanced techniques developed in recent years are capable of improving investigations of this relationship.

Higher Body-Mass Index and Lower Gray Matter Volumes in First Episode of Psychosis

BACKGROUND

Neurostructural alterations are often reported in first episode of psychosis (FEP), but there is heterogeneity in the direction and location of findings between individual studies. The reasons for this heterogeneity remain unknown. Obesity is disproportionately frequent already early in the course of psychosis and is associated with smaller brain volumes. Thus, we hypothesized that obesity may contribute to brain changes in FEP.

METHOD

We analyzed MRI scans from 120 participants with FEP and 114 healthy participants. In primary analyses, we performed voxel-based morphometry (VBM) with small volume corrections to regions associated with FEP or obesity in previous meta-analyses. In secondary analyses, we performed whole-brain VBM analyses.

RESULTS

In primary analyses, we found that when controlling for BMI, FEP had lower GM volume than healthy participants in a) left fronto-temporal region (pTFCE = 0.008) and b) left postcentral gyrus (pTFCE = 0.043). When controlling for FEP, BMI was associated with lower GM volume in left cerebellum (pTFCE < 0.001). In secondary analyses, we found that when controlling for BMI, FEP had lower GM volume than healthy participants in the a) cerebellum (pTFCE = 0.004), b) left frontal (pTFCE = 0.024), and c) right temporal cortex (pTFCE = 0.031). When controlling for FEP, BMI was associated with lower GM volume in cerebellum (pTFCE = 0.004). Levels of C-reactive protein, HDL and LDL-cholesterol correlated with obesity related neurostructural alterations.

CONCLUSIONS

This study suggests that higher BMI, which is frequent in FEP, may contribute to cerebellar alterations in schizophrenia. As previous studies showed that obesity-related brain alterations may be reversible, our findings raise the possibility that improving the screening for and treatment of obesity and associated metabolic changes could preserve brain structure in FEP.

Associations of cardiorespiratory fitness, adiposity, and arterial stiffness with cognition in youth

Purpose

To investigate the associations of cardiorespiratory fitness, adiposity, and arterial stiffness with cognition in 16‐ to 19‐year‐old adolescents.

Methods

Fifty four adolescents (35 girls; 19 boys) participated in the study. Peak oxygen uptake (V̇O_2peak) and peak power output (W_max) were measured by the maximal ramp test on a cycle ergometer and ventilatory threshold (VT) was determined with ventilation equivalents. Lean mass (LM) and body fat percentage (BF%) were measured using a bioelectrical impedance analysis. Aortic pulse wave velocity (PWVao) and augmentation index (AIx%) were measured by a non‐invasive oscillometric device. Working memory, short term memory, visual learning and memory, paired‐associate learning, attention, reaction time, and executive function were assessed by CogState tests.

Results

V̇O_2peak/LM (β = 0.36 p = .011) and W_max/LM (β = 0.30 p = .020) were positively associated with working memory. W_max/LM was also positively associated with visual learning (β = 0.37, p = .009). V̇O₂ at VT/LM was positively associated with working memory (β = 0.30 p = .016), visual learning (β = 0.31 p = .026), and associated learning (β = −0.27 p = .040). V̇O₂ at VT as % of V̇O_2peak, BF%, PWVao, and AIx% were not associated with cognition.

Conclusion

Cardiorespiratory fitness was related to better cognitive function, while BF% and arterial stiffness were not associated with cognition in adolescents.

Adverse labour market impacts of childhood and adolescence overweight and obesity in Western societies-A literature review

Overweight and obesity among children and adolescents are major health issues of today with both somatic and psychosocial consequences in childhood, adolescence and adulthood and potentially adverse effects for adult social life. We conducted a narrative review of the literature about the association of overweight and obesity in childhood and adolescence with possible adverse impact on labour market in adulthood. By PubMed and Google Scholar searches, we identified 12 original, prospective studies from Western countries and extracted data from these studies. We discuss the possible explanations of the associations and the conceptual and methodological challenges in these studies. Despite inherent difficulties in interpreting results, partly due to differences in outcome definitions, ages at exposure, measurements of overweight and obesity, confounder control and societal differences, the studies indicate adverse labour market impacts on adult wage and employment. Furthermore, penalties seemed present even if the excessive weight was lost before adulthood, and women seemed more affected than men, especially when weight persisted into adulthood. While both health and lower education might contribute to explain the adverse labour market outcomes, also discrimination, stigmatization and the development of cognitive and noncognitive skills seemed to influence the outcomes. Prevention of these adverse labour market impacts likely requires multilevel efforts.

Obesity impacts brain metabolism and structure independently of amyloid and tau pathology in healthy elderly

AIMS/HYPOTHESIS

Midlife obesity is a risk factor for dementia. We investigated the impact of obesity on brain structure, metabolism, and cerebrospinal fluid (CSF) core Alzheimer's disease (AD) biomarkers in healthy elderly.

METHODS

We selected controls from ADNI2 with CSF AD biomarkers and/or fluorodeoxyglucose positron emission tomography (FDG-PET) and 3T-MRI. We measured cortical thickness, FDG uptake, and CSF amyloid beta (Aβ)1-42, p-tau, and t-tau levels. We performed regression analyses between these biomarkers and body mass index (BMI).

RESULTS

We included 201 individuals (mean age 73.5 years, mean BMI 27.4 kg/m2). Higher BMI was related to less cortical thickness and higher metabolism in brain areas typically not involved in AD (family-wise error [FWE] <0.05), but not to AD CSF biomarkers. It is notable that the impact of obesity on brain metabolism and structure was also found in amyloid negative individuals.

CONCLUSIONS/INTERPRETATION

In the cognitively unimpaired elderly, obesity has differential effects on brain metabolism and structure independent of an underlying AD pathophysiology.

An Overview on the Associations between Health Behaviors and Brain Health in Children and Adolescents with Special Reference to Diet Quality

Unhealthy diet has been associated with overweight, obesity, increased cardiometabolic risk, and recently, to impaired cognition and academic performance. The aim of this review is to provide an overview of the associations between health behaviors and cognition and academic achievement in children and adolescents under 18 years of age with a special reference to diet quality. Dietary patterns with a low consumption of fish, fruits, and vegetables, and high in fast food, sausages, and soft drinks have been linked to poor cognition and academic achievement. The studies on the associations between the high intake of saturated fat and red meat and low intake of fiber and high-fiber grain products with cognition are limited. The available evidence and physiological mechanisms suggest that diet may have direct, indirect, and synergistic effects on brain and cognition with physical activity, sedentary behaviors, cardiometabolic health, and sleep, but the associations have been modest. Therefore, integrating a healthy diet, physically active lifestyle, and adequate sleep may provide optimal circumstances for brain development and learning. We conclude that most of the existing literature is contained in cross-sectional studies, which therefore highlights the need for longitudinal and intervention studies on the effects of diet, physical activity, sedentary behavior, and sleep on cognition and academic performance.

Associations Among Body Mass Index, Cortical Thickness, and Executive Function in Children

IMPORTANCE

A total of 25.7 million children in the United States are classified as overweight or obese. Obesity is associated with deficits in executive function, which may contribute to poor dietary decision-making. Less is known about the associations between being overweight or obese and brain development.

OBJECTIVE

To examine whether body mass index (BMI) is associated with thickness of the cerebral cortex and whether cortical thickness mediates the association between BMI and executive function in children.

DESIGN, SETTING, AND PARTICIPANTS

In this cross-sectional study, cortical thickness maps were derived from T1-weighted structural magnetic resonance images of a large, diverse sample of 9 and 10-year-old children from 21 US sites. List sorting, flanker, matrix reasoning, and Wisconsin card sorting tasks were used to assess executive function.

MAIN OUTCOMES AND MEASURES

A 10-fold nested cross-validation general linear model was used to assess mean cortical thickness from BMI across cortical brain regions. Associations between BMI and executive function were explored with Pearson partial correlations. Mediation analysis examined whether mean prefrontal cortex thickness mediated the association between BMI and executive function.

RESULTS

Among 3190 individuals (mean [SD] age, 10.0 [0.61] years; 1627 [51.0%] male), those with higher BMI exhibited lower cortical thickness. Eighteen cortical regions were significantly inversely associated with BMI. The greatest correlations were observed in the prefrontal cortex. The BMI was inversely correlated with dimensional card sorting (r = -0.088, P < .001), list sorting (r = -0.061, P < .003), and matrix reasoning (r = -0.095, P < .001) but not the flanker task. Mean prefrontal cortex thickness mediated the association between BMI and list sorting (mean [SE] indirect effect, 0.014 [0.008]; 95% CI, 0.001-0.031) but not the matrix reasoning or card sorting task.

CONCLUSIONS AND RELEVANCE

These results suggest that BMI is associated with prefrontal cortex development and diminished executive functions, such as working memory.

The effects of a 12-week jump rope exercise program on body composition, insulin sensitivity, and academic self-efficacy in obese adolescent girls

Background Childhood obesity is strongly associated with the development of cardiovascular disease (CVD). Exercise interventions have been used for obese children and adolescents to prevent the manifestation of CVD risks, such as hypertension and insulin resistance (IR). Additionally, obesity has been shown to be linked to low self-efficacy in adolescents, which has been shown to negatively impact academic performance. Therefore, the purpose of this study was to examine the effects of a 12-week jump rope exercise program on body composition, CVD risk factors, and academic self-efficacy (ASE) in obese adolescent girls with prehypertension. Methods Adolescent girls with prehypertension and obesity (n = 48, age 14-16 years) were randomly assigned to either the jump rope exercise group (EX, n = 24) or the control group (CON, n = 24). Body composition, blood pressure (BP), blood glucose, insulin levels, homeostatic model assessment of insulin resistance (HOMA-IR) (marker of IR), and ASE were assessed before and after 12 weeks of exercise training or control. Results There were significant group × time interactions following the 12-week exercise program for body fat percent, waist circumference (WC), systolic blood pressure (SBP), blood glucose, insulin levels, and HOMA-IR, which were all significantly reduced (p < 0.05). A significant improvement (p <0.05) was observed in task difficulty preference (TDP) and self-regulatory efficacy (SRE) following exercise training. Additionally, ASE was strongly correlated (r = -0.58) with body composition. Conclusions This study provides evidence that jump rope exercise intervention can be a useful therapeutic treatment to improve CVD risk factors and ASE in obese adolescent girls with prehypertension.

Cognitive Performance as Predictor and Outcome of Adolescent Bariatric Surgery: A Nonrandomized Pilot Study

Objectives

Evidence in adults suggests that improvements in cognitive performance may follow weight loss resulting from bariatric surgery, and baseline cognitive performance may be associated with weight loss following surgery. This has not been evaluated in adolescents.

Method

Participants were 38 adolescents of age 14-21 years composed of three groups: (1) 12 adolescents with severe obesity who received vertical sleeve gastrectomy during the study (VSG); (2) 14 adolescents with severe obesity who were wait-listed for VSG (WL); and (3) 12 healthy weight controls (HC). Participants completed testing of visual memory, verbal memory, and executive functioning at baseline (T1), which occurred presurgery for the VSG group, and approximately 4 months after baseline (T2). Body mass index (BMI) was assessed at T1, T2, and additionally at 6 months following VSG for the adolescents who received surgery.

Results

Although there was evidence of greater improvement for the VSG as compared with WL and HC groups in visual and verbal memory, group differences did not reach significance and effect sizes were small (η2 < 0.01). There was a significant positive association between indices of baseline executive functioning and excess BMI loss at 6 months postsurgery.

Conclusions

This small pilot study showed no significant differences by group in cognitive performance post-VSG. There was a significant association of baseline cognitive performance with weight loss outcomes. Given the very preliminary nature of these results in a small sample, future research should examine these relationships in a larger sample and evaluate mechanisms of these associations (e.g., insulin resistance, sleep, physical activity).

Interaction Effect of Sex and Body Mass Index on Gray Matter Volume

Objective: Few studies have investigated sex differences in brain structure associated with body mass index (BMI), and the related findings are inconsistent. In this study, we aimed to investigate the effect of sex × BMI interactions on gray matter volume (GMV), and to determine the implications of any structural differences.

Methods: The final sample comprised 653 participants (449 women) who were assessed using voxel-based morphology analysis of T1-weighted magnetic resonance images. We used the voxel-based morphometry (VBM) to build a multiple regression model to explore the association between BMI and GMV, and used analysis of variance (ANOVA) to explore the BMI × sex interaction on GMV. A subset of 410 participants (291 women) underwent whole brain resting-state functional connectivity (rsFC) analysis to investigate sex differences in the seed (interaction) region. The cluster with a significant effect in the previous ANOVA analysis was used as a seed.

Results: A significant BMI × sex interaction was observed in the left anterior cingulate cortex (ACC), while GMV was negatively correlated with BMI in men but not in women. The rsFC between the left ACC and the caudate was lower in men than in women. Within the entire sample, the insula, caudate, and medial frontal cortex activities were negatively correlated with BMI while the cerebellum and postcentral gyrus activities were positively correlated with BMI.

Conclusions: Our findings address the interaction effect of BMI and sex on GM alterations. We found that the GMV in men seemed to be more likely to change with BMI than women, and the left ACC may be the reason for the increase in BMI of men, but not women.

The Executive Functions in Overweight and Obesity: A Systematic Review of Neuropsychological Cross-Sectional and Longitudinal Studies

Background: The increasing incidence of people affected by overweight or obesity is a significant health problem. The knowledge of the factors which influences the inappropriate eating behaviors causing excessive body fat is an essential goal for the research. Overweight and obesity are significant risk factors for many health diseases, such as cardiovascular problems, diabetes. Recently, many studies have focused on the relationship between body weight and cognitive processes. Objectives: This systematic review is aimed to investigate the existence and the nature of the relationship between excessive body weight (overweight/obesity) and executive functions, analyzing cross-sectional, and longitudinal studies in order to verify the evidence of a possible causality between these variables. Methods: The review was carried out according to the PRISMA-Statement, through systematic searches in the scientific databases PubMed, Medline, PsychInfo, and PsycArticles. The studies selected examined performance on executive tasks by participants with overweight or obesity, aged between 5 and 70 years. Studies examining eating disorders or obesity resulting from other medical problems were excluded. Furthermore, the results of studies using a cross-sectional design and those using a longitudinal one were separately investigated. Results: Sixty-three cross-sectional studies and twenty-eight longitudinal studies that met our inclusion and exclusion criteria were analyzed. The results confirmed the presence of a relation between executive functions and overweight/obesity, although the directionality of this relation was not clear; nor did any single executive function emerge as being more involved than others in this relation. Despite this, there was evidence of a reciprocal influence between executive functions and overweight/obesity. Conclusions: This systematic review underlines the presence of a relationship between executive functions and overweight/obesity. Moreover, it seems to suggest a bidirectional trend in this relationship that could be the cause of the failure of interventions for weight reduction. The results of this review highlight the importance of a theoretical model able to consider all the main variables of interest, with the aim to structuring integrated approaches to solve the overweight/obesity problems.

Decreased Conflict Control in Overweight Chinese Females: Behavioral and Event-Related Potentials Evidence

Overweight or obesity is related to a decrease in cognitive control, especially conflict control. However, research on conflict control in overweight/obese individuals are still controversial. This study was conducted to explore general and food-related conflict control in overweight Chinese females (OWs) with a color–word Stroop task and a food-related conflict task. Event-related potentials (ERPs) were recorded during the food-related conflict task. Behavioral results showed that, OWs had a longer reaction time (RT) than normal-weight Chinese females (NWs), in both tasks. ERP results in the food-related conflict task showed that there was a reduction of N2 and N450 response strength in OWs, and the P3 and late positive component (LPC) response strength was enhanced. Results indicated that OWs might be less efficient in monitoring and resolving conflict, and OWs tended to have a higher motivational or emotional involvement in processing food-related stimuli, which was likely to contribute to their difficulty in losing weight.

A hypothesis linking the energy demand of the brain to obesity risk

We propose that variation in brain energy expenditure during childhood is an unexplored but important influence on obesity risk. This hypothesis is supported by evidence that the energy required by the developing brain decreases in later childhood as the rate of body weight gain is increasing. The hypothesis is further supported by findings of genetic and brain imaging research indicating a trade-off between the body mass index (BMI) and the volume of cortical and subcortical structures, and inverse associations between BMI and energetically costly executive cognitive functions. Efforts to quantify variability in brain energy use across children could inspire new educational strategies that increase brain energy demands and thereby reduce obesity risk.

The causes of obesity are complex and multifactorial. We propose that one unconsidered but likely important factor is the energetic demand of brain development, which could constrain energy available for body growth and other functions, including fat deposition. Humans are leanest during early childhood and regain body fat in later childhood. Children reaching this adiposity rebound (AR) early are at risk for adult obesity. In aggregate data, the developing brain consumes a lifetime peak of 66% of resting energy expenditure in the years preceding the AR, and brain energy use is inversely related to body weight gain from infancy until puberty. Building on this finding, we hypothesize that individual variation in childhood brain energy expenditure will help explain variation in the timing of the AR and subsequent obesity risk. The idea that brain energetics constrain fat deposition is consistent with evidence that genes that elevate BMI are expressed in the brain and mediate a trade-off between the size of brain structures and BMI. Variability in energy expended on brain development and function could also help explain widely documented inverse relationships between the BMI and cognitive abilities. We estimate that variability in brain energetics could explain the weight differential separating children at the 50th and 70th BMI-for-age centiles immediately before the AR. Our model proposes a role for brain energetics as a driver of variation within a population’s BMI distribution and suggests that educational interventions that boost global brain energy use during childhood could help reduce the burden of obesity.

The development of executive function in early childhood is inversely related to change in body mass index: Evidence for an energetic tradeoff?

A well-established literature demonstrates executive function (EF) deficits in obese children and adults relative to healthy weight comparisons. EF deficits in obesity are associated with overeating and impulsive consumption of high calorie foods leading to excess weight gain and to problems with metabolic regulation and low-grade inflammation that detrimentally affect the structure and function of prefrontal cortex. Here, we test a complementary explanation for the relation between EF and body mass index (BMI) grounded in the energy demand of the developing brain. Recent work shows that the brain accounts for a lifetime peak of 66% of resting metabolic rate in childhood and that developmental changes in brain energetics and normative changes in body weight gain are closely inversely related. This finding suggests a trade-off in early childhood between energy used to support brain development versus energy used to support physical growth and fat deposition. To test this theorized energetic trade-off, we analyzed data from a large longitudinal sample (N = 1,292) and found that change in EF from age 3 to 5 years, as a proxy for brain development in energetically costly prefrontal cortex, is inversely related to change in BMI from age 2 to 5 years. Greater linear decline in BMI predicted greater linear increase in EF. We interpret this finding as tentative support for a brain-body energetic trade-off in early childhood with implications for lifetime obesity risk.

Brain functional imaging in obese and diabetic patients

Obesity and type 2 diabetes are associated with greater risk of brain damage. Over the last decade, functional imaging techniques (functional magnetic resonance imaging, fMRI, positron emission tomography, PET, electroencephalography, magnetoencephalography, near infrared spectroscopy) have been exploited to better characterize behavioral and cognitive processes, by addressing cerebral reactions to a variety of stimuli or tasks, including hormones and substrates (e.g., glucose, insulin, gut peptides), environmental cues (e.g., presentation of sensory stimuli), and cognitive tasks. Among these techniques, fMRI and PET are most commonly used, and this review focuses on results obtained with these techniques in relation to brain substrate metabolism, appetite control and food intake, and cognitive decline in obesity and type 2 diabetes. The available knowledge indicates that there are a series of cerebral abnormalities associating with, or preceding obesity and type 2 diabetes, including impaired substrate handling, insulin resistance, disruption of inter-organ cross-talk and of resting state networking. Some of these abnormalities are reversed by metabolic interventions, suggesting that they are partly a consequence rather than cause of disease. Therefore, causal implications and mechanisms remain to be determined.

Brain and behavioral correlates of insulin resistance in youth with depression and obesity

Depression, together with insulin resistance, is increasingly prevalent among youth. These conditions have traditionally been compartmentalized, but recent evidence suggests that a shared brain motivational network underlies their co-occurrence. We posit that, in the context of depressive symptoms, insulin resistance is associated with aberrant structure and functional connectivity in the Anterior Cingulate Cortex (ACC) and hippocampus. This motivational neural circuit underlies dysfunctional behavioral responses and increased sensitivity to rewarding aspects of ingesting high calorie food that lead to disinhibition of eating even when satiated. To investigate this shared mechanism, we evaluated a sample of forty-two depressed and overweight (BMI > 85th%) youth aged 9 to 17. Using ACC and hippocampus structural and seed-based regions of interest, we investigated associations between insulin resistance, depression, structure (ACC thickness, and ACC and hippocampal area), and resting-state functional connectivity (RSFC). We predicted that aberrant associations among these neural and behavioral characteristics would be stronger in insulin resistant compared to insulin sensitive youth. We found that youth with greater insulin resistance had higher levels of anhedonia and more food seeking behaviors, reduced hippocampal and ACC volumes, and greater levels of ACC and hippocampal dysconnectivity to fronto-limbic reward networks at rest. For youth with high levels of insulin resistance, thinner ACC and smaller hippocampal volumes were associated with more severe depressive symptoms, whereas the opposite was true for youth with low levels of insulin resistance. The ACC-hippocampal motivational network that subserves depression and insulin resistance separately, may represent a critical neural interaction that link these syndromes together.