Cognitive functions among predominantly minority urban adolescents with metabolic syndrome

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.

Association Between Ideal Cardiovascular Health and Executive Function in Chinese Primary School Children

Aims: Little information exists on the associations of cardiovascular health, a new metric proposed by the American Heart Association, and executive function, particularly in children. We aimed to explore this topic.

Methods: We studied 3,798 children aged 6–12 years from 5 schools in Guangzhou, China. The executive function of children was evaluated using parent reports of the Behavioral Rating Inventory of Executive Function, which included 2 composite indexes and 8 subscale scores. We calculated the number of ideal cardiovascular health (range: 0–7) based on smoking, body mass index, physical activity (PA), diet, blood pressure, cholesterol, and glucose. A generalized linear mixed model was used to assess the association of the number of ideal cardiovascular health metrics and executive function.

Results: Compared with children exhibiting 1–3 ideal cardiovascular health metrics, decreases of 1.37–2.63 points (indicating better performance) in metacognition index and its 5 subscale indexes (initiate, working memory, plan/organize, organization of materials, and monitor) were observed in children who attained 5 or 6–7 ideal metrics (all p for trend <0.001). Ideal diet and ideal PA were independently associated with lower indexes of behavioral regulation and metacognition.

Conclusions: The number of ideal cardiovascular health was positively associated with performance of executive function in children.

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.

Metabolic Syndrome and Cognitive Function

PURPOSE OF REVIEW

Metabolic syndrome (MetS) is a cluster of cardiovascular disease risk factors that are related to several adverse health outcomes, including poor cognitive function. This review seeks to summarize and critically review select recent findings on the association between MetS and cognition.

RECENT FINDINGS

MetS was associated with lower domain-specific and global cognitive function in most cross-sectional studies, but findings from longitudinal studies are not consistent. The associations varied depending on age, sex, cognitive test, genetic susceptibility, and the duration of follow-up in prospective studies. MetS was associated with a higher risk of mild cognitive impairment (MCI) and progression from MCI to dementia, particularly vascular dementia. Among MetS components, high blood pressure, high waist circumference, and hyperglycemia were the strongest predictors of cognitive function. MetS is associated with higher risk of cognitive impairment. Research is needed on how preventing or treating MetS affects cognition.

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.

Obesity in childhood, socioeconomic status, and completion of 12 or more school years: a prospective cohort study

OBJECTIVES

Children with obesity achieve lower educational level compared with normal-weight peers. Parental socioeconomic status (SES) impacts both a child's academic achievement and risk of obesity. The degree to which the association between obesity and education depends on parental SES is unclear. Therefore, the primary aim is to investigate if individuals with obesity in childhood are less likely to complete ≥12 years of schooling, independently of parental SES. The secondary aim is to study how weight loss, level of education and parental SES are associated.

DESIGN

Nationwide prospective cohort study.

SETTING

Swedish national register data.

PARTICIPANTS

Children aged 10-17 years, recorded in the Swedish Childhood Obesity Treatment Register, and aged 20 years or older at follow-up were included (n=3942). A comparison group was matched by sex, year of birth and living area (n=18 728). Parental SES was based on maternal and paternal level of education, income and occupational status.

PRIMARY OUTCOME MEASURE

Completion of ≥12 years of schooling was analysed with conditional logistic regression, and adjusted for group, migration background, attention deficit disorder with or without hyperactivity, anxiety/depression and parental SES.

RESULTS

Among those with obesity in childhood, 56.7% completed ≥12 school years compared with 74.4% in the comparison group (p<0.0001). High parental SES compared with low SES was strongly associated with attained level of education in both children with and without obesity, adjusted OR (^aOR) (99% CI)=5.40 (4.45 to 6.55). However, obesity in childhood remains a strong risk factor of not completing ≥12 school years, independently of parental SES, ^aOR=0.57 (0.51 to 0.63). Successful obesity treatment increased the odds of completing ≥12 years in school even when taking parental SES into account, ^aOR=1.34 (1.04 to 1.72).

CONCLUSIONS

Individuals with obesity in childhood have lower odds of completing ≥12 school years, independently of parental SES. Optimised obesity treatment may improve school results in this group.

Childhood Metabolic Biomarkers Are Associated with Performance on Cognitive Tasks in Young Children

OBJECTIVE

To evaluate the hypothesis that metabolic measures (fasting glucose, insulin, and Homeostatic Model of Assessment for Insulin Resistance [HOMA-IR] levels) are inversely associated with performance on cognitive tasks using data from young (4- to 6-year-old), typically developing, healthy children.

STUDY DESIGN

Data were obtained from children participating in the Healthy Start study, a pre-birth cohort in Colorado. HOMA-IR, glucose, and insulin values were centered and scaled using the study sample means and SD. Thus, they are reported in number of SD units from the mean. Fully corrected T scores for inhibitory control (Flanker task), cognitive flexibility (Dimensional Change Card Sort test), and receptive language (Picture Vocabulary test) were obtained via the National Institutes of Health Toolbox cognition battery.

RESULTS

Children included in this analysis (n = 137) were 4.6 years old, on average. Per 1-SD unit, fasting glucose (B = -2.0, 95% CI -3.5, -0.5), insulin (B = -1.7, 95% CI -3.0, -0.4), and HOMA-IR values (B = -1.8, 95% CI -3.1, -0.5) were each significantly and inversely associated with inhibitory control (P < .05 for all, respectively). Fasting glucose levels were also inversely associated with cognitive flexibility (B = -2.0, 95% CI -3.7, -0.2, P = .03).

CONCLUSIONS

Our data suggest that metabolic health may impact fluid cognitive function in healthy, young children.

Association Between Cardiovascular Risk Factors and Stress Hormones With Cognitive Performance in Mexican Adolescents

Objective

The objective of this study was to determine whether cardiovascular disease (CVD) risk factors and stress hormones are associated with cognitive performance in Mexican adolescents.

Methods

This was a cross-sectional study including 139 Mexican adolescents 10-14 years old. Participants were divided into three categories: 0, 1-2, and ≥3 CVD risk factors. These factors included: high-density lipoprotein-cholesterol (HDL-C) <40 mg/dl; waist circumference (WC) ≥90th percentile for age and sex, systolic or diastolic blood pressure ≥90th percentile for age, sex, and height; and triacylglycerols (TGs) ≥110 mg/dl. Low-density lipoprotein-cholesterol (LDL-C), very low-density lipoprotein-cholesterol (VLDL-C), total cholesterol, cortisol, and plasma catecholamines were measured as well. Furthermore, attention, memory, and executive functions were evaluated using a validated test for Spanish-speaking individuals (Neuropsi).

Results

Adolescents in the three risk categories did not show significant differences in Neuropsi test performance tasks; however, they presented different lipid and plasma norepinephrine concentrations. TG and VLDL-C were inversely associated with memory (r = -0.19, **p < .01). Multivariate regression analysis showed consistently that TG/HDL-C ratio was inversely related to attention-memory general score (standardized β = -0.99, t = -2.30, p = .023), memory (standardized β = -0.83, t = -2.08, p = .039), and attention-executive functions (standardized β = -1.02, t = -2.42, p = .017). Plasma epinephrine levels presented an inverse and weak relation to the attention-executive functions score (standardized β = -0.18, t = -2.19, p = .030).

Conclusions

Cognitive performance is not completely dependent on the accumulation of risk factors, but instead on the combination of strong predictors of CVD like waist to height ratio, TG/HDL-C, and VLDL-C. Plasma norepinephrine and epinephrine have a stronger association with cognition and CVD risk than dopamine and cortisol.

The Need for Innovative Methods to Increase Adherence in Individuals Experiencing Cognitive Decline

Cognitive impairment, particularly coupled with advanced age, is becoming an increasing concern for both clinicians and caregivers. Nonadherence is a common problem in individuals with cognitive impairment, leading to concerns regarding patient autonomy. The development and use of innovative strategies to overcome nonadherence is important to increase the likelihood of engagement in healthy lifestyle behaviors.