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

Intelligence and obesity during the obesity epidemic

Several studies conducted during the last 50 years have shown that lower intelligence is associated with a higher body mass index (BMI). During this period, the prevalence of obesity and overweight has increased considerably. We investigated whether this increase has altered the relation between intelligence and BMI by studying two cohorts of 419,319 conscripts, born 1939-1959 and 1983-2001, examined in the same geographical districts in Denmark. While the prevalence of obesity increased from 0.8% in the early to 6.7% in the late cohort, the two cohorts showed essentially the same pattern of relations between intelligence test scores (ITS), prevalence of obesity and overweight (including obesity), and BMI. The prevalence of obesity and overweight and BMI was higher at any ITS value in the late than in the early cohort, but inversely associated with ITS in both cohorts. The ITS displayed inverse J-shaped associations with BMI, with ITS peaking around a BMI of 20 kg/m2 and declining with higher BMI, although with a somewhat steeper decline in the early than in the late cohort. Thus, irrespective of the increase in prevalence of obesity and overweight and in BMI, the pattern of inverse relations between intelligence and higher BMI levels was maintained.

Relationships of the gut microbiome with cognitive development among healthy school-age children

Background

The gut microbiome might play a role in neurodevelopment, however, evidence remains elusive. We aimed to examine the relationship between the intestinal microbiome and cognitive development of school-age children.

Methods

This cross-sectional study included healthy Israeli Arab children from different socioeconomic status (SES). The microbiome was characterized in fecal samples by implementing 16S rRNA gene sequencing. Cognitive function was measured using Stanford-Binet test, yielding full-scale Intelligence Quotient (FSIQ) score. Sociodemographics and anthropometric and hemoglobin measurements were obtained. Multivariate models were implemented to assess adjusted associations between the gut microbiome and FSIQ score, while controlling for age, sex, SES, physical growth, and hemoglobin levels.

Results

Overall, 165 children (41.2% females) aged 6-9 years were enrolled. SES score was strongly related to both FSIQ score and the gut microbiome. Measures of α-diversity were significantly associated with FSIQ score, demonstrating a more diverse, even, and rich microbiome with increased FSIQ score. Significant differences in fecal bacterial composition were found; FSIQ score explained the highest variance in bacterial β-diversity, followed by SES score. Several taxonomic differences were significantly associated with FSIQ score, including Prevotella, Dialister, Sutterella, Ruminococcus callidus, and Bacteroides uniformis.

Conclusions

We demonstrated significant independent associations between the gut microbiome and cognitive development in school-age children.

Effect of the environmental factor of coexistence on the physical condition of people with mild and moderate intellectual disabilities

BACKGROUND

The main objective of this study was to compare the physical condition of people with intellectual disabilities living in residential homes (RH; restricted residential environment) versus independent homes (IH; family houses while performing paid work). The effect of gender on physical condition was also evaluated separately for each group.

METHOD

Sixty individuals with mild to moderate intellectual disability, 30 living in RH and 30 living in IH, participated in this study. The RH and IH groups were homogeneous in terms of gender distribution (17 males and 13 females) and intellectual disability level. Body composition, postural balance, and static and dynamic force were considered as dependent variables.

RESULTS

The IH group performed better in the postural balance and dynamic force tests compared to the RH group, but no significant differences between the groups were observed for any body composition or static force variable. Women in both groups tended to have better postural balance than men, while men presented higher dynamic force.

CONCLUSIONS

The IH group presented a higher physical fitness compared to RH group. This result emphasises the need to increase the frequency and intensity of the physical activity sessions commonly programed for individuals living in RH.

Association between physical fitness, body mass index and intelligence quotient in individuals with intellectual disabilities

BACKGROUND

Physical exercise seems to improve cognitive abilities at different physiological levels. Numerous studies have examined the relationship between physical fitness (PF), physical activity and cognition among populations without intellectual disabilities (ID), but very few have addressed this question with respect to people with ID. This study aimed to determine the correlation between intelligence quotient (IQ) and factors related to PF in healthy adults with ID.

METHODS

A multicentre cross-sectional study was conducted in 91 individuals with ID. All participants were assessed with the K-BIT tests and the following test items from the SAMU DIS-FIT Battery: body mass index, handgrip strength (HGS), leg strength, dynamic balance and physical endurance.

RESULTS

Significant differences between men and women were tested by multiple regression. IQ was found to be statistically related to HGS and leg strength, with a medium effect size. Statistical relationships were also found between sex and physical endurance, with a medium effect size, and HGS, with a large effect size.

CONCLUSIONS

The study results highlight relationships between the variables of muscular strength and the participants' IQ. Further studies with experimental designs are needed to enhance the understanding of the relationships between PF and cognition in persons with ID.

Individual and Environmental Predictors of Age of First Intercourse and Number of Children by Age 27

Reproductive behavior characteristics may be influenced by both social and individual factors. Recent studies have revealed that personality traits might be related to reproductive characteristics in adulthood. Little is known about potential mediators or moderators of relations between personality and reproductive behavior. The present study examines the relation between personality traits measured in early adolescence and the number of children people have by age 27, with an attempt to identify moderation and mediation effects. We used data from the longitudinal cohort (N = 585) collected as a part of the Child Development Project. Personality was measured with the use of Lanthier's Big Five Personality Questionnaire. Results from regression analyses and structural equation models showed that four of the five personality traits (except extraversion) were related to the number of children individuals had by age 27, and these associations were mediated by the age of first intercourse and participants' familial and educational plans. We also identified moderation effects of IQ and SES both on the associations of personality traits with mediators and the number of children by age 27.

Association between intestinal worm infection and malnutrition among rural children aged 9-11 years old in Guizhou Province, China

BACKGROUND

Intestinal worm infection adversely impacted child health and was one of the China's largest health burdens. However, yet little was known about associations between intestinal worm infection and malnutrition in school-aged children in rural China. This study aimed to fill into the gap.

METHODS

Data were from a survey of children aged 9-11 years old in Guizhou Province, China conducted in June 2013. Considering anemia and low intelligent quotient (IQ) as mediating factors, binomial logistic regression was used to estimate the associations of intestinal worm infection with thinness, underweight, and stunting. Moreover, the associations between socio-demographic factors and malnutrition were also explored.

RESULTS

Among 2179 children, part of children was infected by intestinal worm (41.85%). Stunting (28%), low memory IQ (87.52%), and low process IQ (62.59%) were highly prevalent in the sample. Socio-demographic factors were associated with thinness, underweight, stunting, low memory IQ, low process IQ, anaemia, and intestinal worm infection. Intestinal worm infection was associated with low IQ, anemia, and stunting. In addition, anemia and low IQ could not confound the other expected associations.

CONCLUSION

This study demonstrated the association between intestinal worm infections and stunting appeared to be largely mediated via low IQ. The study highlighted the importance of deworming and improving nutrition in the surveyed areas.

Sleeve Gastrectomy for Youth With Cognitive Impairment or Developmental Disability

BACKGROUND AND OBJECTIVES

Youth with cognitive impairment or developmental disability (CI/DD) face higher rates of obesity and secondary medical issues. Bariatric surgery may be a helpful tool for health improvement because it has been shown efficacious for adolescents. We aim to contribute to literature regarding bariatric surgery for adolescents with CI/DD and explore the association between cognitive functioning and weight loss outcomes.

METHODS

Adolescents (N = 64) received a preoperative psychological evaluation, including cognitive assessment, and bariatric surgery at 1 weight loss program between 2010 and 2017. For these adolescents with measured cognitive performance, CI/DD was defined by an IQ <80 or previous diagnosis. In analyses, we compared adolescents with and without CI/DD. Structural equation modeling was used to assess the impact of cognitive functioning on weight loss 3 to 24 months postsurgery.

RESULTS

There were no significant differences between adolescents with or without CI/DD in terms of preoperative BMI, age, and sex. Having CI/DD did not significantly impact weight loss or weight loss trajectory in the 2 years after surgery, although modeling revealed a trend toward individuals with CI/DD losing more weight over time. Similarly, intelligence scores did not predict weight loss after surgery.

CONCLUSIONS

Bariatric surgery may be a helpful tool for adolescents with severe obesity and CI/DD. They could benefit from the surgery as much as those with typical development, and having CI/DD should not be used as a criterion to deny surgery. Continuing research with this population can be used to determine long-term outcomes in addition to defining best practices.

Polymorphisms in Manganese Transporters SLC30A10 and SLC39A8 Are Associated With Children's Neurodevelopment by Influencing Manganese Homeostasis

Background: Manganese (Mn) is an essential element but at excessive levels, it is neurotoxic. Even a moderate increase in Mn has been suggested to interfere with neurodevelopment in children. Genetics influencing Mn concentrations and toxicity is unclear.

Objective: We assessed, in a cross-sectional study, whether common single-nucleotide polymorphisms in the Mn transporters SLC39A8 (influx) and SLC30A10 (efflux) are associated with neurodevelopment in children.

Design: We genotyped SLC39A8 (rs13107325 C/T) and SLC30A10 (rs1776029 G/A and rs12064812 T/C) in Italian children (n = 686, ages 11–14). We then used linear regression models to analyze associations between genotype, blood Mn concentrations, and neurodevelopmental outcomes including intelligence, behavior, motor function, and sway. Inferred causal relationships were evaluated using instrumental variables (IV) analysis.

Results: For SLC30A10 rs1776029, the minor allele (A) was associated with increased average blood Mn of 41% (p < 0.001), whereas minor alleles for rs12064812 (C) and rs13107325 (T) were associated with reduced blood Mn of 7% (p = 0.002) and 15% (p < 0.001), respectively. For children carrying genotypes associated with high blood Mn, we observed lower performance for certain IQ subtests, increased sway, and increased scores for behavioral problems. High Mn genotypes showed odds ratios of 2–4 (p ≤ 0.01) for high scores in tests assessing ADHD-related behavior. IV analyses suggested that several of the associations were mediated by blood Mn.

Conclusions: Our results suggest that common polymorphisms in SLC39A8 and SLC30A10 influence neurodevelopmental outcomes in children via differences in Mn homeostasis.

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.

A systematic review of genetic syndromes with obesity

Syndromic monogenic obesity typically follows Mendelian patterns of inheritance and involves the co-presentation of other characteristics, such as mental retardation, dysmorphic features and organ-specific abnormalities. Previous reviews on obesity have reported 20 to 30 syndromes but no systematic review has yet been conducted on syndromic obesity. We searched seven databases using terms such as 'obesity', 'syndrome' and 'gene' to conduct a systematic review of literature on syndromic obesity. Our literature search identified 13,719 references. After abstract and full-text review, 119 relevant papers were eligible, and 42 papers were identified through additional searches. Our analysis of these 161 papers found that 79 obesity syndromes have been reported in literature. Of the 79 syndromes, 19 have been fully genetically elucidated, 11 have been partially elucidated, 27 have been mapped to a chromosomal region and for the remaining 22, neither the gene(s) nor the chromosomal location(s) have yet been identified. Interestingly, 54.4% of the syndromes have not been assigned a name, whereas 13.9% have more than one name. We report on organizational inconsistencies (e.g. naming discrepancies and syndrome classification) and provide suggestions for improvements. Overall, this review illustrates the need for increased clinical and genetic research on syndromes with obesity.

Obesity and insulin resistance are associated with reduced activity in core memory regions of the brain

Increasing research in animals and humans suggests that obesity may be associated with learning and memory deficits, and in particular with reductions in episodic memory. Rodent models have implicated the hippocampus in obesity-related memory impairments, but the neural mechanisms underlying episodic memory deficits in obese humans remain undetermined. In the present study, lean and obese human participants were scanned using fMRI while completing a What-Where-When episodic memory test (the “Treasure-Hunt Task”) that assessed the ability to remember integrated item, spatial, and temporal details of previously encoded complex events. In lean participants, the Treasure-Hunt task elicited significant activity in regions of the brain known to be important for recollecting episodic memories, such as the hippocampus, angular gyrus, and dorsolateral prefrontal cortex. Both obesity and insulin resistance were associated with significantly reduced functional activity throughout the core recollection network. These findings indicate that obesity is associated with reduced functional activity in core brain areas supporting episodic memory and that insulin resistance may be a key player in this association.

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Obesity associated with reduced activity in core recollection network during episodic memory.

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Insulin resistance associated with reduced activity in core recollection network during episodic memory.

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Insulin resistance, but not obesity, associated with poorer memory performance.

Impact of obesity on outcomes of paediatric acute pancreatitis based on a national administrative database

BACKGROUND

Insufficient information is available on the relationship between obesity and outcome of paediatric patients with acute pancreatitis.

OBJECTIVES

This study aimed to investigate the effect of obesity on outcomes of paediatric patients with acute pancreatitis based on a national administrative database.

METHODS

A total of 500 cases in 416 paediatric patients with acute pancreatitis (aged 5-17 years) were referred from 260 hospitals between 2010 and 2012 in Japan. Patients were divided into two groups according to the presence of obesity: with obesity (n = 65) and without obesity (n = 435). Patient data were collected from the administrative database to compare the prevalence of severe acute pancreatitis, in-hospital mortality, length of stay (LOS) and medical costs between the groups.

RESULTS

Both prevalence of severe acute pancreatitis and in-hospital mortality were significantly higher in paediatric patients with obesity than those without (36.9% vs. 16.3% and 3.1% vs. 0.0%; P < 0.001, respectively). Longer LOS and higher medical costs were also observed in paediatric patients with obesity (25.7 vs. 15.2 days, P < 0.001 and 14 169.5 vs. 7457.7 US dollars, P < 0.001, respectively).

CONCLUSION

This study demonstrated that obesity significantly influenced the outcomes of paediatric acute pancreatitis.

Challenges in the Detection of Working Memory and Attention Decrements among Overweight Adolescent Girls

BACKGROUND

The present study is unique in employing unusually difficult attention and working memory tasks to reveal subtle cognitive decrements among overweight/obese adolescents. It evaluated novel measures of background electroencephalographic (EEG) activity during one of the tasks and tested correlations of these and other measures with psychological and psychiatric predictors of obesity maintenance or progression.

METHODS

Working memory and sustained attention tasks were presented to 158 female adolescents who were rated on dichotomous (body mass index percentile <85 vs. ≥85) and continuous (triceps skinfold thickness) measures of adiposity.

RESULTS

The results revealed a significant association between excess adiposity and performance errors during the working memory task. During the sustained attention task, overweight/obese adolescents exhibited more EEG frontal beta power as well as greater intraindividual variability in reaction time and beta power across task periods than their normal-weight peers. Secondary analyses showed that frontal beta power during the sustained attention task was positively correlated with anxiety, panic, borderline personality features, drug abuse, and loss of control over food intake.

CONCLUSIONS

The findings suggest that working memory and sustained attention decrements do exist among overweight/obese adolescent girls. The reliable detection of the decrements may depend on the difficulty of the tasks as well as the manner in which performance and brain activity are measured. Future studies should examine the relevance of these decrements to dietary education efforts and treatment response.

Study of resilience and environmental adversity in midlife health (STREAM)

PURPOSE

The Jerusalem study of resilience and environmental adversity in midlife health (STREAM) was established to examine the prevalence of common mental and physical health issues in mid-adulthood in the inner city of Jerusalem, and to examine their association with lifespan psychosocial factors of vulnerability and resilience.

METHOD

Participants were 811 randomly selected individuals from 7000 individuals who were born and grew up in inner-Jerusalem. Participants were 34-44 years old during first wave of STREAM assessment. Initial telephone surveys took place in 2007-2008 and participants were followed-up for a second survey 1 year later. Upon funding, a new wave is planned for 2017-2018. Survey topics comprised common health problems (e.g., type 2 diabetes/migraine), health markers (e.g., BMI), and psychiatric vulnerabilities (e.g., anxiety, post-traumatic stress, depressive symptoms, psychosis). Other measures included socioeconomic status, creativity, life style behavior (e.g., smoking, exercise), social contact and adaptation to change. Survey data were retrospectively merged with data of national registry sources that included adverse psychosocial factors, psychiatric and social measures assessed across all developmental stages through midlife. This includes data available on birth factors, school achievement and adjustment, cognitive and behavioral functioning during young adulthood, psychiatric hospitalizations, immigration and socioeconomic status.

RESULTS

Results on health outcomes of the first STREAM wave indicate that prevalence rates of health problems are comparable to recent World Mental Health Surveys.

CONCLUSIONS

Apart from measures on adverse psychosocial factors, STREAM provides a cohort to examine resilience to developing health problems and having a poor health and functional outcome.