Cognitive profile, parental education and BMI in children: reflections on common neuroendrocrinobiological roots

Executive function differences as a function of parent-reported binge eating and weight: Results from the adolescent brain cognitive development study

Background

Binge eating is a relatively common disordered eating behavior among children, and is associated with poor health outcomes. Executive function (EF)-higher order cognitive abilities related to planning and impulse control-may be implicated in both binge eating and pediatric obesity. Although EF deficits are evident among individuals with obesity and/or binge eating, findings are mixed across the lifespan.

Methods

The present study examined differences in EF among children with varying weight statuses and parent-reported binge eating. The sample included 10,017 children from the Adolescent Brain Cognitive Development study, aged 9-10 years.

Results

Children with parent-reported binge eating-either with overweight/obesity or normal weight-had significantly lower EF than those with no binge eating and a normal weight status but did not differ from those with no binge eating and overweight/obesity. Children with no binge eating and overweight/obesity also had statistically significantly lower EF than those with normal weight status. Although all significant differences between groups were negligible to very small, results may indicate similar neurocognitive profiles among children with binge eating and those with overweight/obesity.

Conclusions

Alterations in EF among children with binge eating may not be solely related to weight-specific factors, as significant differences also emerged among children with normal weight status, with versus without parent-reported binge eating. Future research is needed to understand temporal associations between obesity, disordered eating, and neurocognition in children using multi-informant methods for assessing binge eating.

Profiles of Resilience among Children Exposed to Non-Maltreatment Adverse Childhood Experiences

Considering the high prevalence and negative consequences of non-maltreatment adverse childhood experiences (NM-ACEs), it is critical to understand their impacts on the resilient functioning of young children. This study sought to examine heterogeneity in resilience among first-grade children who were exposed to NM-ACEs during kindergarten and explore demographic and adversity characteristics that distinguish between resilience profiles. Latent profile analysis (LPA) was conducted on 4929 children drawn from the Early Childhood Longitudinal Study—Kindergarten (ECLS-K). The results of the LPA revealed four distinct resilience profiles: (1) low cognitive and executive functioning (4%); (2) low social and behavioral functioning (14%); (3) low average functioning (31%); and (4) multi-domain resilience (51%). Female children and those in families characterized by older maternal age, higher parental education level, household income above 200% federal poverty level, not receiving welfare benefits, and races other than Black were more likely to be in the multi-domain resilience profile. The findings highlight heterogeneity in resilience among children exposed to NM-ACEs and point to the need for a comprehensive, multi-domain assessment of child functioning to support optimal resilience development in this population.

Parental Education, Household Income, Race, and Children's Working Memory: Complexity of the Effects

Background. Considerable research has linked social determinants of health (SDoHs) such as race, parental education, and household income to school performance, and these effects may be in part due to working memory. However, a growing literature shows that these effects may be complex: while the effects of parental education may be diminished for Blacks than Whites, household income may explain such effects. Purpose. Considering race as sociological rather than a biological construct (race as a proxy of racism) and built on Minorities' Diminished Returns (MDRs), this study explored complexities of the effects of SDoHs on children's working memory. Methods. We borrowed data from the Adolescent Brain Cognitive Development (ABCD) study. The total sample was 10,418, 9- and 10-year-old children. The independent variables were race, parental education, and household income. The primary outcome was working memory measured by the NIH Toolbox Card Sorting Test. Age, sex, ethnicity, and parental marital status were the covariates. To analyze the data, we used mixed-effect regression models. Results. High parental education and household income were associated with higher and Black race was associated with lower working memory. The association between high parental education but not household income was less pronounced for Black than White children. This differential effect of parental education on working memory was explained by household income. Conclusions. For American children, parental education generates unequal working memory, depending on race. This means parental education loses some of its expected effects for Black families. It also suggests that while White children with highly educated parents have the highest working memory, Black children report lower working memory, regardless of their parental education. This inequality is mainly because of differential income in highly educated White and Black families. This finding has significant public policy and economic implications and suggests we need to do far more than equalizing education to eliminate racial inequalities in children's cognitive outcomes. While there is a need for multilevel policies that reduce the effect of racism and social stratification for middle-class Black families, equalizing income may have more returns than equalizing education.

Executive and Reward-Related Function in Pediatric Obesity: A Meta-Analysis

OBJECTIVE

This study examined the effect of pediatric obesity on executive function and reward-related decision-making, cognitive processes that are relevant to obesogenic behaviors, and evaluated their association with sample (e.g., age, gender, intelligence, and socioeconomic status, SES) and study/task (e.g., categorical/continuous variable, food stimuli) characteristics.

METHODS

A random-effects meta-analysis was conducted using Hedge's g effect sizes of published studies from 1960 to 2016, limited to children younger than the age of 21 years without medical comorbidities. Analysis included estimation of heterogeneity (τ²), publication bias (funnel-plot symmetry and fail-safe N), and sensitivity analyses for sample and study/task characteristics.

RESULTS

Across 68 studies with 70 samples, obesity was associated with worse functioning overall (-0.24; 95CI: -0.30 to -0.19; p < 0.001) and for each component process (attention, switching, inhibition, interference, working memory, reward, delay of gratification: -0.19 to -0.38; p's < 0.017), except trait impulsivity (-0.06; 95CI: -0.18 to 0.07). Deficits increased with age and female composition of the sample for inhibition (p = 0.002). No other characteristics moderated effect of obesity.

CONCLUSIONS

Small-to-moderate negative associations with obesity were observed for executive and reward-related performance, but not on reported impulsivity in studies with children younger than the age of 21 years. These results were not moderated by IQ, SES, and study/task characteristics. Age and gender moderated association with inhibition, with a larger obesity-related deficit in older and predominantly female samples. These results suggest cognitive and demographic intervention targets for prevention and mitigation of obesogenic behavior.

Maternal and offspring intelligence in relation to BMI across childhood and adolescence

Objective

The present study tested the association between both mothers’ and offspring’s intelligence and offspring’s body mass index (BMI) in youth.

Method

Participants were members of the National Longitudinal Survey of Youth 1979 (NLSY-79) Children and Young Adults cohort (n = 11,512) and their biological mothers who were members of the NLSY-79 (n = 4932). Offspring’s IQ was measured with the Peabody Individual Achievement Test (PIAT). Mothers’ IQ was measured with the Armed Forces Qualification Test (AFQT). A series of regression analyses tested the association between IQ and offspring’s BMI by age group, while adjusting for pre-pregnancy BMI and family SES. The analyses were stratified by sex and ethnicity (non-Black and non-Hispanic, Black, and Hispanic).

Results

The following associations were observed in the fully adjusted analyses. For the non-Blacks and non-Hispanics, a SD increment in mothers’ IQ was negatively associated with daughters’ BMI across all age-groups, ranging from β = −0.12 (95% CI −0.22 to −0.02, p = 0.021) in late childhood, to β = −0.17 (95% C.I. −0.27 to −0.07, p = 0001), in early adolescence and a SD increment in boys’ IQ was positively associated with their BMI in early adolescence β = 0.09 (95% CI 0.01–0.18, p = 0.031). For Blacks, there was a non-linear relationship between mothers’ IQ and daughters’ BMI across childhood and between girls’ IQ and BMI across adolescence. There was a positive association between mothers’ IQ and sons’ BMI in early adolescence (β = 0.17, 95% CI 0.02–0.32, p = 0.030). For Hispanic boys, there was a positive IQ-BMI association in late childhood (β = 0.19, 95% CI 0.05–0.33, p = 0.008) and early adolescence (β = 0.17, 95% CI 0.04–0.31, p = 0.014).

Conclusion

Mothers’ IQ and offspring’s IQ were associated with offspring’s BMI. The relationships varied in direction and strength across ethnicity, age group and sex. Obesity interventions may benefit from acknowledging the heterogeneous influence that intelligence has on childhood BMI.

School effects on non-verbal intelligence and nutritional status in rural Zambia

This study uses hierarchical linear modeling (HLM) to examine the school factors (i.e., related to school organization and teacher and student body) associated with non-verbal intelligence (NI) and nutritional status (i.e., body mass index; BMI) of 4204 3^rd to 7^th graders in rural areas of Southern Province, Zambia. Results showed that 23.5% and 7.7% of the NI and BMI variance, respectively, were conditioned by differences between schools. The set of 14 school factors accounted for 58.8% and 75.9% of the between-school differences in NI and BMI, respectively. Grade-specific HLM yielded higher between-school variation of NI (41%) and BMI (14.6%) for students in grade 3 compared to grades 4 to 7. School factors showed a differential pattern of associations with NI and BMI across grades. The distance to a health post and teacher's teaching experience were the strongest predictors of NI (particularly in grades 4, 6 and 7); the presence of a preschool was linked to lower BMI in grades 4 to 6. Implications for improving access and quality of education in rural Zambia are discussed.

Relation of intelligence quotient and body mass index in preschool children: a community-based cross-sectional study

OBJECTIVE

Overweight and obesity in children is a global problem. Besides physical effects, obesity has harmful psychological effects on children.

METHODS

We carried out cross-sectional community-based study to investigate the relation between body mass index (BMI) and cognitive functioning in preschool children. Thirteen socioeconomical elements of 1151 children were measured and analyzed based on their intelligence quotient (IQ) test results. Thirteen out of 33 provinces were selected randomly, and schools were selected as clusters in rural and urban areas. Descriptive statistics, t-test, analysis of variance and regression were used when appropriate.

RESULTS

Our analysis showed that IQ was associated with household income, place of residence, delivery type, type of infant feeding and father's and mother's education level (P<0.001 for all). Using penalized linear regression for eliminating the impact of confounding factor, our study shows that, living in metropolitan (β=2.411) and urban areas (β=2.761), the level of participants' father's education (β=5.251) was positively and BMI (β=-0.594) was negatively related with IQ test results.ConclusionsThe findings of the present study showed that a lower IQ score is associated with higher BMI. However, this relation appears to be largely mediated when the socioeconomic status was considered.

Impact of obesity on cognitive outcome in children with sleep-disordered breathing

OBJECTIVES

The objective of this study was to evaluate the impact of obesity on cognitive impairment, in children with obstructive sleep apnoea (OSA), children with OSA and obesity, and in normal controls.

METHODS

Thirty-six children with OSA (group 1), 38 children with OSA and obesity (group 2) and 58 normal controls (group 3) were studied. The Total intelligence quotient (T-IQ), Verbal IQ (V-IQ) and the Performance IQ (P-IQ) scores were obtained using the Wechsler Intelligence Scale for Children - Third Edition Revised. All participants' parents filled out the questionnaire containing the attention deficit and hyperactive disorder rating scale to investigate symptoms of hyperactivity and attention deficit. Obese and non-obese children with sleep-disordered breathing (SDB) underwent polysomnography.

RESULTS

T-QI and P-QI scores were significantly lower in group 2 with higher performance impairment at the subtest compared to other groups. In obese children, V-IQ was significantly correlated with age of onset (r = 0.335, p = 0.05) and duration of SDB (r = -0.362, p = 0.02), while P-IQ and T-IQ were correlated with body mass index (BMI) percentile (r = -0.341, p = 0.03) and respiratory disturbance index (RDI) (r = -0.321, p = 0.05), respectively. RDI and BMI negatively influenced T-IQ in obese children with OSA. No correlation was found between sleep parameters and IQ scores or subtest scores in all groups.

CONCLUSIONS

Obese children with OSA showed higher cognitive impairment. Obesity has an additive and synergic action with that exerted by OSA, speeding up the onset of complications.

Obesity-associated biomarkers and executive function in children

There is a growing focus on links between obesity and cognitive decline in adulthood, including Alzheimer's disease. It is also increasingly recognized that obesity in youth is associated with poorer cognitive function, specifically executive functioning skills such as inhibitory control and working memory, which are critical for academic achievement. Emerging literature provides evidence for possible biological mechanisms driven by obesity; obesity-associated biomarkers such as adipokines, obesity-associated inflammatory cytokines, and obesity-associated gut hormones have been associated with learning, memory, and general cognitive function. To date, examination of obesity-associated biology with brain function has primarily occurred in animal models. The few studies examining such biologically mediated pathways in adult humans have corroborated the animal data, but this body of work has gone relatively unrecognized by the pediatric literature. Despite the fact that differences in these biomarkers have been found in association with obesity in children, the possibility that obesity-related biology could affect brain development in children has not been actively considered. We review obesity-associated biomarkers that have shown associations with neurocognitive skills, specifically executive functioning skills, which have far-reaching implications for child development. Understanding such gut-brain associations early in the lifespan may yield unique intervention implications.

IQ and obesity in adolescence: a population-based, cross-sectional study

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT

Low IQ is associated with high BMI in childhood. There are inconsistent findings on the association between low SES and high BMI. Youth with low IQ have been reported to have poorer health behaviors, such as poor nutrition and less physical activity.

WHAT THIS STUDY ADDS

Low IQ is significantly associated with obesity for both male and female adolescents, though more strongly for female adolescents. Physical activity has a mediating effect on the association between low IQ and obesity among both male and female adolescents, though more strongly for male adolescents. The association between low IQ and obesity is strongest among adolescents from high SES backgrounds.

BACKGROUND

Previous studies have shown an association between low intelligence quotient (IQ), high body mass index and low socioeconomic status (SES).

OBJECTIVES

This study examined the cross-sectional association between IQ and obesity, exploring the roles of gender, SES and physical activity in this association.

METHODS

Subjects were 235,663 male and 169,259 female adolescents assessed by the Israeli military draft board.

RESULTS

Low IQ was significantly associated with increased odds of obesity among male (odds ratio [OR] = 1.44, 95% confidence interval [CI] = 1.36-1.52) and female adolescents (OR = 1.61, 95% CI = 1.51-1.73); this association was significantly stronger among female adolescents. Sobel tests indicated that physical activity had a significant mediating effect on this association for male and female adolescents, although more strongly for male adolescents. Dividing the sample according to SES, the association between low IQ and obesity was strongest in the high SES group (male adolescents: OR = 1.26, 95% CI = 1.10-1.43, female adolescents: OR = 1.61, 95% CI = 1.38-1.89), even when controlling for physical activity.

CONCLUSIONS

The findings suggest that low IQ is associated with increased odds of obesity, particularly in female adolescents and in adolescents with high SES. Physical activity has a mediating effect on this association, although more strongly for male than for female adolescents. Public health measures on decreasing obesity might focus on these groups.

Physical growth and nonverbal intelligence: associations in Zambia

OBJECTIVE

To investigate normative developmental body mass index (BMI) trajectories and associations of physical growth indicators--height, weight, head circumference (HC), and BMI--with nonverbal intelligence in an understudied population of children from sub-Saharan Africa.

STUDY DESIGN

A sample of 3981 students (50.8% male), grades 3-7, with a mean age of 12.75 years was recruited from 34 rural Zambian schools. Children with low scores on vision and hearing screenings were excluded. Height, weight, and HC were measured, and nonverbal intelligence was assessed using the Universal Nonverbal Intelligence Test, Symbolic Memory subtest and Kaufman Assessment Battery for Children, Second Edition, Triangles subtest.

RESULTS

Students in higher grades had a higher BMI over and above the effect of age. Girls had a marginally higher BMI, although that for both boys and girls was approximately 1 SD below the international Centers for Disease Control and Prevention and World Health Organization norms. When controlling for the effect of age, nonverbal intelligence showed small but significant positive relationships with HC (r = 0.17) and BMI (r = 0.11). HC and BMI accounted for 1.9% of the variance in nonverbal intelligence, over and above the contribution of grade and sex.

CONCLUSION

BMI-for-age growth curves of Zambian children follow observed worldwide developmental trajectories. The positive relationships between BMI and intelligence underscore the importance of providing adequate nutritional and physical growth opportunities for children worldwide and in sub-Saharan Africa in particular. Directions for future studies are discussed with regard to maximizing the cognitive potential of all rural African children.

Attention-deficit/hyperactivity disorder, iron deficiency, and obesity: is there a link?

The exact etiopathophysiology of attention-deficit/hyperactivity disorder (ADHD) remains elusive, likely because of its phenotypic heterogeneity. Given the involvement of iron in neurocognitive and behavioral functions, iron deficiency (ID) has been suggested as a possible etiopathophysiological factor in a subsample of individuals with ADHD. Most studies assessing ID in ADHD have focused on serum ferritin, a marker of peripheral iron status. Results from these studies are mixed, and the largest studies failed to find a significant association between ADHD and low serum ferritin levels. However, serum ferritin may be influenced by several conditions, including inflammatory status. Increasing evidence, especially from epidemiological studies, points to a significant association between ADHD and obesity. Interestingly, obesity is associated with a chronic inflammatory status, characterized by ID with normal-to-high serum ferritin levels. This article reviews the literature on iron status in ADHD and on the relationship between ADHD and obesity; discusses a possible link among ADHD, ID, and obesity; and proposes that comorbid obesity contributes to ID, via chronic inflammation, in a subsample of individuals with ADHD. Thus, the comorbidity between ADHD and obesity suggests moving beyond serum ferritin levels and assessing the molecular pathways of chronic inflammation that lead to ID in individuals with ADHD and obesity. In turns, this may pave the way for novel treatment strategies for cognitive and behavioral dysfunctions related to ID in ADHD.

Is obesity a risk factor for impaired cognition in young adults with low birth weight?

BACKGROUND

Overweight and obesity are risk factors for cardiovascular disease. There is also an association between body mass index (BMI) and cognitive ability. Since low birth weight is associated with adult metabolic disease, particularly in obese subjects, the question emerges whether obesity has an additional negative effect on cognitive function in subjects with low birth weight.

OBJECTIVES

The aim was to analyse whether overweight or obesity influence intellectual performance in young adults with particular focus on those with a low birth weight.

METHODS

Data were collected from the Swedish Medical Birth Register on 620,834 males born between 1973 and 1988 and matched to results on intellectual performance and BMI at conscription.

RESULTS

The risk for low intellectual performance was higher for those with high BMI compared to those with normal. The highest risk was found among subjects with low birth weight and overweight or obesity in young adulthood (odds ratios, 1.98 [1.73-2.22] and 2.59 [2.00-3.34], respectively). However, subjects with further high birth weight and a high BMI at conscription had no further increased risk.

CONCLUSIONS

Overweight and obesity are associated with an increased risk of subnormal intellectual performance in young adult males. Subjects with low birth weight and adolescent overweight/obesity are at particular risk of subnormal performance. A high birth weight increases the risk for obesity, but a high adult BMI does not further increase the risk for subnormal performance.

Obesity-Related Hormones in Low-Income Preschool-Age Children: Implications for School Readiness

Mechanisms underlying socioeconomic disparities in school readiness and health outcomes, particularly obesity, among preschool-aged children are complex and poorly understood. Obesity can induce changes in proteins in the circulation that contribute to the negative impact of obesity on health; such changes may relate to cognitive and emotion regulation skills important for school readiness. We investigated obesity-related hormones, body mass index (BMI), and school readiness in a pilot study of low-income preschoolers attending Head Start (participating in a larger parent study). We found that the adipokine leptin was related to preschoolers' BMI z-score, the appetite-regulating hormones ghrelin and glucagon-like peptide 1 (GLP-1), and pro-inflammatory cytokines typically associated with early life stress; and that some of these obesity-related biomarkers were in turn related to emotion regulation. Future work should evaluate how obesity may affect multiple domains of development, and consider modeling common physiological pathways related to stress, health, and school readiness.

Impact of metabolic syndrome on cognition and brain: a selected review of the literature

Metabolic syndrome (MetS), a clustering of risk factors for type 2 diabetes mellitus and cardiovascular disease, has been associated with cognitive dysfunction and brain abnormalities. This review describes the literature on the impact of MetS on brain and cognition and suggests directions for future research. A literature search for reports of MetS and cognition and brain imaging was conducted for both nonelderly adults and adolescents. No studies were found describing MetS and brain or cognition among adolescents; therefore, we also included studies investigating individual components of MetS in this age group. Most studies found associations between MetS and cognitive dysfunction. Multiple cognitive domains were affected by MetS in adults. In adolescents, the majority of findings were in executive functioning. Brain imaging literature in adults implicated MetS in ischemic stroke, white matter alterations, and altered brain metabolism. For adolescents, individual MetS factors were linked to volume losses in the hippocampus and frontal lobes. MetS negatively impacts cognitive performance and brain structure. Potential explanatory models include impaired vascular reactivity, neuroinflammation, oxidative stress, and abnormal brain lipid metabolism. We posit that insulin resistance-associated impairment in cerebrovascular reactivity is an important mechanism underlying brain deficits seen in MetS.

Four-year longitudinal performance of a population-based sample of healthy children on a neuropsychological battery: the NIH MRI study of normal brain development

The National Institutes of Health (NIH) Magnetic Resonance Imaging (MRI) Study of Normal Brain Development is a landmark study in which structural and metabolic brain development and behavior are followed longitudinally from birth to young adulthood in a population-based sample of healthy children. Cross-sectional findings from the neuropsychological test battery have been previously described (Waber et al., 2007). The present report details 4-year longitudinal neuropsychological outcomes for those children who were aged 6 to 18 years at baseline (N = 383), of whom 219 (57.2%) completed all 3 visits. Primary observations were (1) individual children displayed considerable variation in scores across visits on the same measures; (2) income-related differences were more prominent in the longitudinal than in the cross-sectional data; (3) no association between cognitive and behavioral measures and body mass index; and (4) several measures showed practice effects, despite the 2-year interval between visits. These data offer an unparalleled opportunity to observe normative performance and change over time on a set of standard and commonly used neuropsychological measures in a population-based sample of healthy children. They thus provide important background for the use and interpretation of these instruments in both research settings and clinical practice.