Obesity, inflammation and cognition

A comparative study of cognitive function and reaction time in obese and non-obese adults

OBJECTIVE

Obesity may negatively affect the physical health and cognitive functions of individuals and delay their reaction time to stimuli. However, the association among obesity, cognitive functions, and reaction times is yet to be fully elucidated. The aim of this study was to assess the effect of obesity on cognitive functions and visual and auditory reaction times in adults.

METHODS

Data of 100 participants (50 obese and 50 normal) were analyzed in the study. Anthropometric parameters and 24-h dietary recall data were recorded. The Montreal Cognitive Assessment (MoCA) was used to evaluate the cognitive functions, Simple Reaction Time Task (SRTT)-Visual and SRTT-Auditory were used to assess visual and auditory reaction times of the participants, respectively.

RESULTS

The mean MoCA score of the obese was significantly lower than normal (17.46 and 25.22, respectively; p < 0.001). In addition, the mean auditory (p < 0.001) and visual (p < 0.05) reaction times of obese were significantly longer than normal. Similarly, this condition was also observed for the fastest and lowest values of auditory and visual reaction times. Additionally, obesity caused a decrease in the MoCA score (β = -0.762; p < 0.001) and delayed visual (β = 0.423; p < 0.001) and auditory (β = 0.590; p < 0.001) reactions. The negative effect of obesity was maintained after controlling for potential factors (MoCA, β = -0.594; p < 0.001; SRTT-Auditory, β = 0.409; p < 0.01; SRTT-Visual, β = 0.330; p < 0.05).

CONCLUSION

Obese participants showed worse cognitive, auditory and visual performance. Additional research will be necessary in the future to shed light on the fundamental mechanisms involved.

Bariatric Surgery Is Associated With Reduced Incidence of Mild Cognitive Impairment and Alzheimer Disease and Related Dementias: A Retrospective Cohort Study

Objective

To evaluate the association of bariatric surgery with reduced incidence and delayed development of mild cognitive impairment (MCI) and Alzheimer disease and related dementias (ADRD) in patients with obesity.

Background

This retrospective longitudinal study utilized Electronic Health Records from Vanderbilt University Medical Center, covering 5303 patients who underwent bariatric surgery and 10,606 propensity score-matched obese patients who did not, from 2000 to 2023. Patients with prior MCI, ADRD, schizophrenia, alcoholism, gastric cancer, gastric ulcers, inflammatory bowel disease, coagulopathy, stroke, Parkinson disease, or brain cancer were excluded from both groups.

Methods

Differences in time to MCI/ADRD between surgical and control groups were analyzed using linear regression, and adjusted for confounders: demographics, medical history, and socioeconomic status. Survival probability differences for MCI and ADRD between the 2 groups over time were assessed using Kaplan-Meier curves and log-rank tests. Incidence differences of MCI and ADRD between the groups were evaluated using Fine-Gray subdistribution hazard models, accounting for the competing risk of death and confounders.

Results

Bariatric surgery was associated with a significantly reduced incidence of ADRD, evidenced by a subdistribution hazard ratio (SHR) of 0.37 (95% confidence interval [CI]: 0.15-0.89; P = 0.03). Similarly, the incidence of MCI was significantly lower in the surgical group, with an SHR of 0.57 (95% CI: 0.39-0.85; P = 0.01). Additionally, patients who underwent bariatric surgery experienced a delay of 2.01 years before developing MCI compared with the control group (95% CI: 0.70-3.50; P = 0.004).

Conclusions

These findings suggest that bariatric surgery may serve as an effective strategy to delay the onset of MCI and reduce the risk of both MCI and ADRD in patients with obesity.

Assessing the Role of Dark Sweet Cherry (Prunus avium L.) Consumption on Cognitive Function, Neuropeptides, and Circadian Rhythm in Obesity: Results from a Randomized Controlled Trial

Background/Objectives: Obesity is linked to a higher risk of cognitive impairment. The objective of this single blind randomized trial was to evaluate the impact of dark sweet cherry (DSC) intake on cognitive function in obese adults. Methods: Participants (body mass index (BMI): 30-40 kg/m2, >18 years, without chronic diseases and/or antibiotic use) consumed 200 mL of DSC drink with 3 g of cherry powder (n = 19) or an isocaloric placebo drink (n = 21) twice daily for 30 days. Cognitive function was assessed at Day 1 (D1) and Day 30 (D30) using standardized cognitive tests and the NeuroTracker (NT) 3D training program. Blood biomarkers related to cognitive health (neurotensin, substance p, and oxytocin) and circadian rhythm (melatonin and cortisol) were assessed at D1 and D30 using a Luminex multiplex bead-based immunoassay. Results: DSC supplementation significantly improved working memory and concentration, as indicated by higher scores in the digit span forward (DSF, p = 0.006) and backward (DSB, p = 0.01) tests. However, processing speed, sustained attention, and visual spatial skills, assessed through the trail making (TMT) and digit symbol substitution (DSST) tests, as well as visual cognitive performance (VCP) evaluated by the NT program, showed no significant differences between groups. Neurotensin, associated with cognitive deficits, increased in both cherry and placebo groups but was significant only in the placebo group (p = 0.007). Similarly, melatonin increased in both groups, reaching significance only in the placebo group (p = 0.02), and it correlated positively with IFNγ, suggesting a compensatory response to inflammation. Conclusions: These findings suggest DSC supplementation may enhance specific cognitive functions in obese adults. Further clinical trials are needed to confirm these results.

Inflammation and cognitive performance in elite athletes: A cross-sectional study

Functional cognition is relevant for athletic success and interdependent with physical exercise, yet despite repeatedly demonstrated inflammatory responses to physical training, there are no studies addressing the relationship between cognition and inflammation in athletes. The aim of this study was to investigate the relationship between cognitive performance and selected inflammatory, and further physiological biomarkers in elite athletes. Data from 350 elite athletes regarding cognitive performance (processing speed, selective attention, working memory, cognitive flexibility), systemic inflammatory markers, metabolic hormones, growth factors, tissue damage markers, and micronutrients (e.g., ferritin, 25-OH-vitamin D), as well as physiological, subjective ratings of recovery and stress were analysed by correlative and multiple regression analyses. Results show that across all athletes variance in processing speed, selective attention, and working memory, could be best explained through a combination of metabolic hormones with physiological and psychological indicators of stress, and in cognitive flexibility through vitamin D levels. Only for the subgroup of athletes from closed-skill sports, the ratio TNF-α:IL-10 significantly contributed to explanation of variance in working memory and cognitive flexibility. In general, found correlations point to the importance of inflammatory balance and sufficient long-term nutrient supply for unaffected cognitive performance.

Interplay between preclinical indices of obesity and neural signatures of fluid intelligence in youth

Pediatric obesity rates have quadrupled in the United States, and deficits in higher-order cognition have been linked to obesity, though it remains poorly understood how deviations from normal body mass are related to the neural dynamics serving cognition in youth. Herein, we determine how age- and sex-adjusted measures of body mass index (zBMI) scale with neural activity in brain regions underlying fluid intelligence. Seventy-two youth aged 9-16 years underwent high-density magnetoencephalography while performing an abstract reasoning task. The resulting data were transformed into the time-frequency domain and significant oscillatory responses were imaged using a beamformer. Whole-brain correlations with zBMI were subsequently conducted to quantify relationships between zBMI and neural activity serving abstract reasoning. Our results reveal that participants with higher zBMI exhibit attenuated theta (4-8 Hz) responses in both the left dorsolateral prefrontal cortex and left temporoparietal junction, and that weaker temporoparietal responses scale with slower reaction times. These findings suggest that higher zBMI values are associated with weaker theta oscillations in key brain regions and altered performance during an abstract reasoning task. Thus, future investigations should evaluate neurobehavioral function during abstract reasoning in youth with more severe obesity to identify the potential impact.

The relationship between uric acid levels, cognition and inflammation in a cohort of elderly subjects

BACKGROUND

Uric acid (UA) is the most powerful antioxidant found among human body fluids. With this effect, UA protects neurons from oxidant effects and ensures the continuation of the structure and functions of neuronal tissue. However, UA has effects on the immune system. This study aims to explain the relationship between UA, cognitive level and inflammation in cases with a wide spectrum of cognitive function.

METHODS

A total of 67 women and 62 men who applied to the psychiatry outpatient clinic to obtain a health report were evaluated. The cognitive states of the individuals were determined with the mini-mental state examination test (MMSE). Additionally, serum uric acid levels and simple inflammatory parameters such as CRP, sedimentation, neutrophil-lymphocyte ratio (NLR), and monocyte-lymphocyte ratio (MLR) were measured. According to the MMSE results, two groups were created. Those with an MMSE score of 24 or above formed the first group, and those with an MMSE score below 24 formed the second group.

RESULTS

While a statistically significant positive strong correlation was found between UA and MMSE in all individuals, negative correlations were found between UA and NLR and MLR in men. UA was found to be significantly lower in the group with MMSE scores below 24 and NLR values were higher in the same group.

CONCLUSION

According to these results, UA seems to have a protective effect on cognitive functions. This situation manifests itself more clearly in men. At physiological concentrations, UA may have an anti-inflammatory effect. It appears that there are complex interactions between UA, cognition, and inflammation. Particularly, men appear to be more susceptible to UA effects.

Peripheral inflammation is associated with impaired sadness recognition in euthymic bipolar patients

BACKGROUND

Inflammation impairs cognitive function in healthy individuals and people with psychiatric disorders, such as bipolar disorder (BD). This effect may also impact emotion recognition, a fundamental element of social cognition. Our study aimed to investigate the relationships between pro-inflammatory cytokines and emotion recognition in euthymic BD patients and healthy controls (HCs).

METHODS

We recruited forty-four euthymic BD patients and forty healthy controls (HCs) and measured their inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and TNF-α. We applied validated cognitive tasks, the Wisconsin Card-Sorting Test (WCST) and Continuous Performance Test (CPT), and a social cognitive task for emotion recognition, Diagnostic Analyses of Nonverbal Accuracy, Taiwanese Version (DANVA-2-TW). We analyzed the relationships between cytokines and cognition and then explored possible predictive factors of sadness recognition accuracy.

RESULTS

Regarding pro-inflammatory cytokines, TNF-α was elevated in euthymic BD patients relative to HCs. In euthymic BD patients only, higher TNF-α levels were associated with lower accuracy of sadness recognition. Regression analysis revealed that TNF-α was an independent predictive factor of sadness recognition in patients with euthymic BD when neurocognition was controlled for.

CONCLUSIONS

We demonstrated that enhanced inflammation, indicated by increased TNF-α, was an independent predictive factor of impaired sadness recognition in BD patients but not in HCs. Our findings suggested a direct influence of TNF-α on sadness recognition and indicated vulnerability to depression in euthymic BD patients with chronic inflammation.

A biobehavioural and social-structural model of inflammation and executive function in pediatric chronic health conditions

Evidence indicates that pediatric chronic health conditions (CHCs) often impair executive functioning (EF) and impaired EF undermines pediatric CHC management. This bidirectional relationship likely occurs due to biobehavioural and social-structural factors that serve to maintain this feedback loop. Specifically, biobehavioural research suggests that inflammation may sustain a feedback loop that links together increased CHC severity, challenges with EF, and lower engagement in health promoting behaviours. Experiencing social and environmental inequity also maintains pressure on this feedback loop as experiencing inequities is associated with greater inflammation, increased CHC severity, as well as challenges with EF and engagement in health promoting behaviours. Amidst this growing body of research, a model of biobehavioural and social-structural factors that centres inflammation and EF is warranted to better identify individual and structural targets to ameliorate the effects of CHCs on children, families, and society at large. This paper proposes this model, reviews relevant literature, and delineates actionable research and clinical implications.

Incidence of microvascular dysfunction is increased in hyperlipidemic mice, reducing cerebral blood flow and impairing remote memory

Introduction

The development of cognitive dysfunction is not necessarily associated with diet-induced obesity. We hypothesized that cognitive dysfunction might require additional vascular damage, for example, in atherosclerotic mice.

Methods

We induced atherosclerosis in male C57BL/6N mice by injecting AAV-PCSK9DY (2x1011 VG) and feeding them a cholesterol-rich Western diet. After 3 months, mice were examined for cognition using Barnes maze procedure and for cerebral blood flow. Cerebral vascular morphology was examined by immunehistology.

Results

In AAV-PCSK9DY-treated mice, plaque burden, plasma cholesterol, and triglycerides are elevated. RNAseq analyses followed by KEGG annotation show increased expression of genes linked to inflammatory processes in the aortas of these mice. In AAV-PCSK9DY-treated mice learning was delayed and long-term memory impaired. Blood flow was reduced in the cingulate cortex (-17%), caudate putamen (-15%), and hippocampus (-10%). Immunohistological studies also show an increased incidence of string vessels and pericytes (CD31/Col IV staining) in the hippocampus accompanied by patchy blood-brain barrier leaks (IgG staining) and increased macrophage infiltrations (CD68 staining).

Discussion

We conclude that the hyperlipidemic PCSK9DY mouse model can serve as an appropriate approach to induce microvascular dysfunction that leads to reduced blood flow in the hippocampus, which could explain the cognitive dysfunction in these mice.

Deep learning-based BMI inference from structural brain MRI reflects brain alterations following lifestyle intervention

Obesity is associated with negative effects on the brain. We exploit Artificial Intelligence (AI) tools to explore whether differences in clinical measurements following lifestyle interventions in overweight population could be reflected in brain morphology. In the DIRECT-PLUS clinical trial, participants with criterion for metabolic syndrome underwent an 18-month lifestyle intervention. Structural brain MRIs were acquired before and after the intervention. We utilized an ensemble learning framework to predict Body-Mass Index (BMI) scores, which correspond to adiposity-related clinical measurements from brain MRIs. We revealed that patient-specific reduction in BMI predictions was associated with actual weight loss and was significantly higher in active diet groups compared to a control group. Moreover, explainable AI (XAI) maps highlighted brain regions contributing to BMI predictions that were distinct from regions associated with age prediction. Our DIRECT-PLUS analysis results imply that predicted BMI and its reduction are unique neural biomarkers for obesity-related brain modifications and weight loss.

Individual and dual trajectories of insomnia symptoms and body mass index before and after retirement and their associations with changes in subjective cognitive functioning

BACKGROUND

We examined individual and dual trajectories of insomnia symptoms and body mass index (BMI) before and after retirement, and their associations with changes in subjective cognitive functioning after retirement.

METHODS

We used the Helsinki Health Study's (n = 2360, 79% women, aged 40-60 at baseline, Finland) repeated surveys to identify the developmental patterns of insomnia symptoms and BMI (2000-2017) and changes in subjective cognitive functioning (2017-2022). We analysed the data using latent group-based dual trajectory modelling and logistic regression analysis.

RESULTS

Three latent groups were identified for insomnia symptoms (stable low, decreasing and increasing symptoms) and BMI (stable healthy weight, stable overweight and stable obesity). Insomnia symptoms were associated with declining subjective cognitive functioning and largely explained the effects in the dual models.

CONCLUSION

The association between dual trajectories of insomnia symptoms and BMI with subjective cognitive decline is dominated by insomnia symptoms.

The cerebellum plays more than one role in the dysregulation of appetite: Review of structural evidence from typical and eating disorder populations

OBJECTIVE

Dysregulated appetite control is characteristic of anorexia nervosa (AN), bulimia nervosa (BN), and obesity (OB). Studies using a broad range of methods suggest the cerebellum plays an important role in aspects of weight and appetite control, and is implicated in both AN and OB by reports of aberrant gray matter volume (GMV) compared to nonclinical populations. As functions of the cerebellum are anatomically segregated, specific localization of aberrant anatomy may indicate the mechanisms of its relationship with weight and appetite in different states. We sought to determine if there were consistencies in regions of cerebellar GMV changes in AN/BN and OB, as well as across normative (NOR) variation.

METHOD

Systematic review and meta-analysis using GingerALE.

RESULTS

Twenty-six publications were identified as either case-control studies (nOB  = 277; nAN/BN  = 510) or regressed weight from NOR data against brain volume (total n = 3830). AN/BN and OB analyses both showed consistently decreased GMV within Crus I and Lobule VI, but volume reduction was bilateral for AN/BN and unilateral for OB. Analysis of the NOR data set identified a cluster in right posterior lobe that overlapped with AN/BN cerebellar reduction. Sensitivity analyses indicated robust repeatability for NOR and AN/BN cohorts, but found OB-specific heterogeneity.

DISCUSSION

Findings suggest that more than one area of the cerebellum is involved in control of eating behavior and may be differentially affected in normal variation and pathological conditions. Specifically, we hypothesize an association with sensorimotor and emotional learning via Lobule VI in AN/BN, and executive function via Crus I in OB.

Exercise Reshapes the Brain: Molecular, Cellular, and Structural Changes Associated with Cognitive Improvements

Physical exercise is well known as a non-pharmacological and holistic therapy believed to prevent and mitigate numerous neurological conditions and alleviate ageing-related cognitive decline. To do so, exercise affects the central nervous system (CNS) at different levels. It changes brain physiology and structure, promoting cognitive improvements, which ultimately improves quality of life. Most of these effects are mediated by neurotrophins release, enhanced adult hippocampal neurogenesis, attenuation of neuroinflammation, modulation of cerebral blood flow, and structural reorganisation, besides to promote social interaction with beneficial cognitive outcomes. In this review, we discuss, based on experimental and human research, how exercise impacts the brain structure and function and how these changes contribute to cognitive improvements. Understanding the mechanisms by which exercise affects the brain is essential to understand the brain plasticity following exercise, guiding therapeutic approaches to improve the quality of life, especially in obesity, ageing, neurodegenerative disorders, and following traumatic brain injury.

Growth Velocities Across Distinct Early Life Windows and Child Cognition: Insights from a Contemporary US Cohort

OBJECTIVE

To evaluate the relative importance of overall and period-specific postnatal growth and their interaction with fetal growth on cognition in a generally well-nourished population.

STUDY DESIGN

We included 1052 children from Project Viva, a prospective cohort in Boston, Massachusetts. Using linear spline mixed-effects models, we modeled length/height and body mass index (BMI) trajectories from birth to 7 years and estimated standardized overall (0-7 years) and period-specific growth velocities ie, early infancy (0-4 months), late infancy (4-15 months), toddlerhood (15-37 months), and early childhood (37-84 months). We investigated associations of growth velocities as well as their interactions with birthweight-for-gestational age on mid-childhood (mean age: 7.9 years) IQ, visual memory and learning, and visual motor ability.

RESULTS

Greater overall height velocity was associated with modestly higher design memory score, (adjusted β [95% CI] 0.19 [-0.01,0.38] P = .057])points per SD increase but lower verbal IQ (-0.88 [-1.76,0.00] P = .051). Greater early infancy height velocity was associated with higher visual motor score (1.92 [0.67,3.18]). Greater overall BMI velocity was associated with lower verbal IQ (-0.71 [-1.52,0.11] P = .090). Greater late infancy BMI velocity was associated with lower verbal IQ (-1.21 [-2.07,-0.34]), design memory score (-0.22 [-0.42,-0.03)], but higher picture memory score (0.22 [0.01,0.43]). Greater early infancy height velocity (-1.5 SD vs 1.5 SD) was associated with higher nonverbal IQ (margins [95% CI] 102.6 [98.9106.3] vs 108.2 [104.9111.6]) among small-for-gestational age infants (P-interaction = 0.04).

CONCLUSIONS

Among generally well-nourished children, there might not be clear cognitive gains with faster linear growth except for those with lower birthweight-for-gestational age, revealing the potential importance of early infancy compensatory growth.

Triangulating causality between childhood obesity and neurobehavior: Behavioral genetic and longitudinal evidence

Childhood obesity is a serious health concern that is not yet fully understood. Previous research has linked obesity with neurobehavioral factors such as behavior, cognition, and brain morphology. The causal directions of these relationships remain mostly untested. We filled this gap by using the Adolescent Brain Cognitive Development study cohort comprising 11,875 children aged 9-10. First, correlations between the age- and sex-specific 95th BMI percentile (%BMIp95) and neurobehavioral measures were cross-sectionally analyzed. Effects were then aggregated by neurobehavioral domain for causal analyses. Behavioral genetic Direction of Causation modeling was used to test the direction of each relationship. Findings were validated by longitudinal cross-lagged panel modeling. %BMIp95 correlated with impulsivity, motivation, psychopathology, eating behavior, and cognitive tests (executive functioning, language, memory, perception, working memory). Greater %BMIp95 was also associated with reduced cortical thickness in frontal and temporal brain areas but with increased thickness in parietal and occipital areas. Similar although weaker patterns emerged for cortical surface area and volume. Behavioral genetic modeling suggested causal effects of %BMIp95 on eating behavior (β = 0.26), cognition (β = 0.05), cortical thickness (β = 0.15), and cortical surface area (β = 0.07). Personality/psychopathology (β = 0.09) and eating behavior (β = 0.16) appeared to influence %BMIp95. Longitudinal evidence broadly supported these findings. Results regarding cortical volume were inconsistent. Results supported causal effects of obesity on brain functioning and morphology. The present study highlights the importance of physical health for brain development and may inform interventions aimed at preventing or reducing pediatric obesity. RESEARCH HIGHLIGHTS: A continuous measure related to obesity, %BMIp95, has correlations with various measures of brain functioning and structure Behavioral genetic and longitudinal modeling suggest causal links from personality, psychopathology, and eating behavior to %BMIp95 Results also indicate directional links from %BMIp95 to eating behavior, cognition, cortical thickness, and cortical surface area Obesity may play a role for healthy brain development during childhood.

Neuroinflammation: A Modifiable Pathway Linking Obesity, Alzheimer's disease, and Depression

Obesity, depression and Alzheimer's disease (AD) are three major interrelated modern health conditions with complex relationships. Early-life depression may serve as a risk factor for AD, while late-life depression may be a prodrome of AD. Depression affects approximately 23% of obese individuals, and depression itself raises the risk of obesity by 37%. Mid-life obesity independently increases AD risk, while late-life obesity, particularly metabolically healthy obesity, may offer protection against AD pathology. Chronic inflammation serves as a key mechanism linking obesity, AD, and depression, encompassing systemic inflammation from metabolic disturbances, immune dysregulation through the gut microbiome, and direct interactions with amyloid pathology and neuroinflammation. In this review, we explore the biological mechanisms of neuroinflammation in relation to obesity, AD, and depression. We assess the efficacy of therapeutic interventions targeting neuroinflammation and discuss current and future radiological imaging initiatives for studying neuroinflammation. By comprehending the intricate interplay among depression, obesity, and AD, especially the role of neuroinflammation, we can advance our understanding and develop innovative strategies for prevention and treatment.

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.

The Association of Obesity and Overweight with Executive Functions in Community-Dwelling Older Women

Among the risk factors reported for cognitive decline, the literature highlights changes in body composition. Thus, the aim of the present study was to examine the relationship between obesity/overweight and executive functions in cognitively normal older adult women. This cross-sectional study included 224 individuals (60-80 years), stratified into normal weight (n = 45), overweight (n = 98), and obesity (n = 81). As outcomes, body mass index (BMI), waist circumference (WC), and Trail Making Test Parts A and B were assessed. We found positive correlations of BMI and WC with completion times of TMT-A and TMT-B, and a negative correlation of BMI and WC with education. ANCOVA showed an association between higher BMI and slower completion time of TMT-A, TMT-B, and ΔTMT (B-A). Impairment of executive functions of cognitively normal older women may be positively associated with obesity and negatively associated with years of education. The findings may contribute to designing strategies that make it possible to prevent cognitive decline in women during aging.

Obesity Is Associated With Gait Alterations and Gait Asymmetry in Older Adults

OBJECTIVES

The prevalence of obesity (OB) has increased in the older adult (OA) population. However, it is not quite clear whether OB exaggerates gait instability and leads to a higher risk of falls in OAs. The first goal of this study was to investigate whether OB is associated with gait alterations and gait asymmetry in OAs. The second goal of this study was to examine relationships between various OB measures with gait measures and gait symmetry measures in OAs.

METHODS

A total of 30 OAs were included and categorized according to their body mass index (BMI) values into groups of persons with normal weight (NW), overweight (OW), and OB. Participants were required to complete an anthropometric assessment, a body composition assessment, and overground walking tests.

RESULTS

The group with OB had shorter swing phase, longer stance phase, and shorter single support phase than the NW group. Increased body weight, BMI, visceral adipose tissue mass, and android fat had correlations with shorter swing phase, longer stance phase, and shorter single support phase. Increased body weight and BMI had significantly positive correlations with symmetry index of knee range of motion.

CONCLUSIONS

OB may impair gait automation capacity in OAs. Both body weight and BMI remain good measures in terms of establishing correlations with gait stability in OAs. However, the amount of fat mass surrounding the abdomen could be vital to interpreting the alterations in the gait of OAs with obesity.

Chronic Home Radon Exposure Is Associated with Higher Inflammatory Biomarker Concentrations in Children and Adolescents

Children are particularly vulnerable to the deleterious impacts of toxic environmental exposures, though the effects of some rather ubiquitous toxins have yet to be characterized in youths. One such toxin, radon gas, is known to accumulate to hazardous levels in homes, and has been linked with the incidence of lung cancer in aging adults. However, the degree to which chronic home radon exposure may impact risk for health problems earlier in life is unknown. Herein, we explored the degree to which chronic home radon exposure relates to biomarkers of low-grade inflammation in 68 youths ages 6- to 14 years old residing in an area of the United States prone to high home radon concentrations. Parents completed a home radon test kit, and youths provided a saliva sample to assess concentrations of five biomarkers. Using a multiple regression approach, we found that greater radon exposure was specifically associated with higher levels of C-reactive protein (β = 0.31, p = 0.007) and interleukin-1β (β = 0.33, p = 0.016). The data suggested specificity in associations between chronic home radon exposure and different biomarkers of inflammatory activity and highlight a pathway which may confer risk for future mental and physical health maladies.

Association of Psychological distress and Physical Health with Subjective and Objective Memory in Older Adults

ObjectivesTo investigate how indicators of psychological stress and physical health differentially influence subjective and objective memory in older adults. Methods: 404 adults aged ≥55 without cognitive impairment participated in remote assessment of physical health (PHY; multimorbidity, body-mass-index), psychological distress (PDS; perceived stress, anxiety, depression), subjective memory complaints (SM), and task-based objective memory performance (OM). Results: Separately, both PHY and PDS significantly predicted SM (p < 0.01), but only PHY was associated with OM (p = 0.05). Combined models showed that PHY and PDS maintained significant association with SM (p < 0.01, R² = 0.30), while only PHY was associated with OM (p = .07, R² = 0.03; for associative OM, p = 0.04). Discussion: SM is associated with participants' psychological profile, highlighting the importance of addressing these factors when assessing SM. The results also reveal that remotely-administered OM tasks are more immune to participants' psychological profile, and support previously-established links between physical health and objective and subjective memory function.

The effects of an obesogenic diet on behavior and cognition in zebrafish (Danio rerio): Trait average, variability, repeatability, and behavioral syndromes

The obesity epidemic, largely driven by the accessibility of ultra-processed high-energy foods, is one of the most pressing public health challenges of the 21st century. Consequently, there is increasing concern about the impacts of diet-induced obesity on behavior and cognition. While research on this matter continues, to date, no study has explicitly investigated the effect of obesogenic diet on variance and covariance (correlation) in behavioral traits. Here, we examined how an obesogenic versus control diet impacts means and (co-)variances of traits associated with body condition, behavior, and cognition in a laboratory population of ~160 adult zebrafish (Danio rerio). Overall, an obesogenic diet increased variation in several zebrafish traits. Zebrafish on an obesogenic diet were significantly heavier and displayed higher body weight variability; fasting blood glucose levels were similar between control and treatment zebrafish. During behavioral assays, zebrafish on the obesogenic diet displayed more exploratory behavior and were less reactive to video stimuli with conspecifics during a personality test, but these significant differences were sex-specific. Zebrafish on an obesogenic diet also displayed repeatable responses in aversive learning tests whereas control zebrafish did not, suggesting an obesogenic diet resulted in more consistent, yet impaired, behavioral responses. Where behavioral syndromes existed (inter-class correlations between personality traits), they did not differ between obesogenic and control zebrafish groups. By integrating a multifaceted, holistic approach that incorporates components of (co-)variances, future studies will greatly benefit by quantifying neglected dimensions of obesogenic diets on behavioral changes.

Psychobiological foundations of coping and emotion regulation: Links to maltreatment and depression in a racially diverse, economically disadvantaged sample of adolescent girls

Adolescent risk for depression and passive or active suicidal ideation (PASI) involves disturbance across multiple systems (e.g., arousal regulatory, affective valence, neurocognitive). Exposure to maltreatment while growing up as a child or teenager may potentiate this risk by noxiously impacting these systems. However, research exploring how coordinated disturbance across these systems (i.e., profiles) might be uniquely linked to depressogenic function, and how past maltreatment contributes to such disturbance, is lacking. Utilizing a racially diverse, economically disadvantaged sample of adolescent girls, this person-centered study identified psychobiological profiles and linked them to maltreatment histories, as well as current depressive symptoms and PASI. Girls (N = 237, Mage=13.98, SD=0.85) who were non-depressed/non-maltreated (15.1%), depressed/non-maltreated (40.5%), or depressed/maltreated (44.4%) provided morning saliva samples, completed questionnaires, a clinical interview, and a neurocognitive battery. Latent profile analysis of girls' morning cortisol:C-reactive protein ratio, positive and negative affect levels, and attentional set-shifting ability revealed four profiles. Relative to Normative (66.6%), girls exhibiting a Pro-inflammatory Affective Disturbance (13.1%), Severe Affective Disturbance (10.1%), or Hypercortisol Affective Neurocognitive Disturbance (n = 24, 10.1%) profile reported exposure to a greater number of maltreatment subtypes while growing up. Girls exhibiting these dysregulated profiles were also more likely (relative to Normative) to report current depressive symptoms (all three profiles) and PASI (only Pro-inflammatory Affective Disturbance and Hypercortisol Affective Neurocognitive Disturbance). Of note, girls' cognitive reappraisal utilization moderated profile membership-depression linkages (depressive symptoms, but not PASI). A synthesis of the findings is presented alongside implications for person-centered tailoring of intervention efforts.

Atherogenic Risk, Anthropometry, Diet and Physical Activity in a Sample of Spanish Commercial Airline Pilots

Cardiovascular accidents are the most disabling event for pilots, causing complicated situations during flight and the withdrawal of license. The study aims to assess the modifiable risk factors and the atherogenic index of plasma (AIP) associated with anthropometric, physiometabolic and lifestyle profiles in a sample of Spanish aviation pilots. Data from pilots’ clinical and professional history, anthropometric and bioelectrical impedance assessments of nutritional status, and diet and physical activity questionnaires. The sample comprised 304 men pilots. Up to 53.6% showed excess weight, of which 6.4% were obese, 64.3% presented high relative adiposity and 64.6% showed abdominal obesity. Regarding the physiometabolic profile, 10.0% had hypertension, 42.6% hypercholesterolemia, 9.4% high LDL and 10.6% low HDL, 9.4% hyperglycemia and 8.1% hypertriglyceridemia. The adherence to the Mediterranean diet (MedDiet) was high in 29.7% and low in 14.7%. Most of the sample showed a good physical activity level. The AIP risk increased with higher obesity indicators and LDL cholesterol levels. There was an inverse relationship between the MedDiet adherence and vigorous physical activity and the risk of atherogenicity. Elevated rates of overweight, abdominal obesity and hypercholesterolemia were found, contributing to the atherogenic risk of plasma (AIP). This parameter was significantly associated with all anthropometric indicators and LDL cholesterol. Prevention plans on reducing excess fat and blood cholesterol levels are recommended to reduce cardiovascular risk in Spanish aviation pilots and ensure flight safety.

One-Year Prospective Association of BMI with Later Cognitive Development in Preschoolers

This study examined the prospective relationships between preschoolers' body mass index (BMI) and cognitive development. BMI, cognitive (i.e., Brigance), sex, and age data were collected from seven cohorts of children attending Head Start from 2012 to 2018. Children (N = 324) with two years of complete data were included. After controlling for the first year cognitive development scores, age, gender, and the cohort, the BMI was predictive of lower cognitive development scores in year two (B = -0.06, β = -0.14, t = -3.19, p = 0.002). Female sex (B = 2.69, β = 0.10, t = 2.30, p = 0.022) and older age (B = 0.02, β = 0.15, t = 3.20, p ≤ 0.001) were also shown to be statistically significant predictors of improved year two cognitive scores. The initial BMI scores were associated with poorer one year cognitive development scores in this sample of preschool children. Excessive body mass may contribute to numerous biological, psychological, and social factors that inhibit children with obesity from reaching their full cognitive potential, during a time in which brain development and cognitive skills development are at critical points of growth. Early childhood obesity interventions may have positive consequences for cognitive development, but additional prospective studies are needed to confirm these results.

Inflammation mediates depression and generalized anxiety symptoms predicting executive function impairment after 18 years

INTRODUCTION

Scar theories propose that elevated depression and anxiety can predispose people to future decreased executive function (EF) via heightened inflammation across decades. However, more longitudinal (versus cross-sectional) research on this topic is needed.

OBJECTIVE

We thus investigated if increased major depressive disorder (MDD), generalized anxiety disorder (GAD), and panic disorder (PD) severity predicted EF decrement 18 years later via heightened inflammation.

METHOD

Community-dwelling adults participated in this study. Time 1 (T1) MDD, GAD, and PD severity (Composite International Diagnostic Interview-Short Form), T2 inflammation (interleukin-6, C-reactive protein, and fibrinogen blood levels concentration), and T2 and T3 EF (Brief Test of Adult Cognition by Telephone) were measured. The waves of assessment were spaced approximately 9 years apart. Structural equation modeling was conducted.

RESULTS

Higher T1 MDD and GAD (but not PD) severity forecasted elevated T2 inflammation (Cohen's d = 0.116-0.758). Greater T2 inflammation level predicted lower T3 EF following 9 years (d = -0.782--0.636). The T1 MDD-T3 EF and T1 GAD-T3 EF negative associations were mediated by T2 inflammation, and explained 38% and 19% of the relations, respectively. Direct effects of higher T1 GAD and MDD predicting lower T3 EF were also observed (d = -0.585--0.560). Significant effects remained after controlling for socio-demographic, lifestyle, medication use, various illness variables across time, and T2 EF.

CONCLUSIONS

Inflammation may be a mechanism explaining the T1 MDD-T3 EF and T1 GAD-T3 EF relations. Treatments that target inflammation, worry, and/or depression may prevent future EF decline.

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 Mass Index Predicts Decline in Executive Function in Bipolar Disorder: Preliminary Data of a 12-Month Follow-up Study

INTRODUCTION

Obesity and associated risk factors have been linked to cognitive decline before.

OBJECTIVES

In the present study, we evaluated potential cumulative negative effects of overweight and obesity on cognitive performance in euthymic patients with bipolar disorder (BD) in a longitudinal design.

METHODS

Neurocognitive measures (California Verbal Learning Test, Trail Making Test [TMT] A/B, Digit-Symbol-Test, Digit-Span, d2 Test), anthropometrics (e.g., body mass index [BMI]), and clinical ratings (Hamilton Depression Scale, Young Mania Rating Scale) were collected over a 12-month observation period. Follow-up data of 38 patients with BD (mean age 40 years; 15 males, 23 females) were available.

RESULTS

High baseline BMI predicted a decrease in the patient's performance in the Digit-Span backwards task measuring working memory performance. In contrast, cognitive performance was not predicted by increases in BMI at follow-up. Normal weight bipolar patients (n = 19) improved their performance on the TMT B, measuring cognitive flexibility and executive functioning, within 1 year, while overweight bipolar patients (n = 19) showed no change in this task.

CONCLUSIONS

The results suggest that overweight can predict cognitive performance changes over 12 months.

Obesity, putative biological mediators, and cognitive function in a national sample of children and adolescents

Childhood obesity has reached epidemic rates nationwide and may be associated with impaired cognitive function. A growing body of evidence suggests that poorer academic performance for children with obesity and overweight is related to declines in executive function skills. This study aimed to identify biological mediators between obesity and overweight and cognitive function among children and adolescents. A total of 3323 children aged 6-16 years from the Third National Health and Nutrition Examination Survey between 1988 and 1994 (NHANES III) was used to measure associations between measures of obesity and overweight, cognitive function (IQ test batteries), iron deficiency, inflammation (c-reactive protein), and glucose metabolism (glycosylated hemoglobin) using multiple mediation models. Approximately 15% of the children were overweight and 11% were obese. Results showed lower scores for children who were obese or overweight than children of normal weight on several IQ subtest batteries. Obesity and overweight were also associated with biological mediators such as iron deficiency, elevated c-reactive protein and glycosylated hemoglobin. Several biomarkers of iron status were also related to measures of cognitive function. Early declines in cognitive function are associated with biomarkers of iron deficiency and inflammation in children and adolescents, and while some biological linkages between obesity and overweight and cognitive function are identified herein, further study is needed to identify additional biological mediators between obesity and overweight and cognitive function in pediatric populations.

Lifestyle-dependent microglial plasticity: training the brain guardians

Lifestyle is one of the most powerful instruments shaping mankind; the lifestyle includes many aspects of interactions with the environment, from nourishment and education to physical activity and quality of sleep. All these factors taken in complex affect neuroplasticity and define brain performance and cognitive longevity. In particular, physical exercise, exposure to enriched environment and dieting act through complex modifications of microglial cells, which change their phenotype and modulate their functional activity thus translating lifestyle events into remodelling of brain homoeostasis and reshaping neural networks ultimately enhancing neuroprotection and cognitive longevity.

A variant near DHCR24 associates with microstructural properties of white matter and peripheral lipid metabolism in adolescents

Visceral adiposity has been associated with altered microstructural properties of white matter in adolescents. Previous evidence suggests that circulating phospholipid PC(16:0/2:0) may mediate this association. To investigate the underlying biology, we performed a genome-wide association study (GWAS) of the shared variance of visceral fat, PC(16:0/2:0), and white matter microstructure in 872 adolescents from the Saguenay Youth Study. We further studied the metabolomic profile of the GWAS-lead variant in 931 adolescents. Visceral fat and white matter microstructure were assessed with magnetic resonance imaging. Circulating metabolites were quantified with serum lipidomics and metabolomics. We identified a genome-wide significant association near DHCR24 (Seladin-1) encoding a cholesterol-synthesizing enzyme (rs588709, p = 3.6 × 10-8); rs588709 was also associated nominally with each of the three traits (white matter microstructure: p = 2.1 × 10-6, PC(16:0/2:0): p = 0.005, visceral fat: p = 0.010). We found that the metabolic profile associated with rs588709 resembled that of a TM6SF2 variant impacting very low-density lipoprotein (VLDL) secretion and was only partially similar to that of a HMGCR variant. This suggests that the effect of rs588709 on VLDL lipids may arise due to altered phospholipid rather than cholesterol metabolism. The rs588709 was also nominally associated with circulating concentrations of omega-3 fatty acids in interaction with visceral fat and PC(16:0/2:0), and these fatty acid measures showed robust associations with white matter microstructure. Overall, the present study provides evidence that the DHCR24 locus may link peripheral metabolism to brain microstructure, an association with implications for cognitive impairment.

Executive Functioning in Extreme Obesity: Contributions from Metabolic Status, Medical Comorbidities, and Psychiatric Factors

PURPOSE

Extreme obesity has been associated with cognitive deficits across the lifespan and may be a risk factor for dementia in later life. However, the relationship between obesity and domain-specific cognitive deficits is complicated by a body of literature that often fails to adequately account for medical and psychiatric conditions frequently co-occurring with extreme obesity.

MATERIALS AND METHODS

The present study included a cross-sectional evaluation of adults with extreme obesity (n=117) compared to lean control (n=46) participants on a brief cognitive battery using the NIH Toolbox and Rey Auditory Verbal Learning Test. Specifically, this study evaluated measures of executive functioning, attention, processing speed, learning, and memory while accounting for many common obesity-related medical and psychiatric comorbidities with known cognitive effects.

RESULTS

Results revealed group differences with lower performances on measures of executive functioning, processing speed, and learning (ps<0.01) for participants with obesity. Reduced executive functioning was associated with abdominal obesity and medication use (ps<0.01) and together contributed significantly to overall modeling of cognition in individuals with obesity.

CONCLUSION

Individuals with extreme obesity in this sample showed lower cognitive performance on measures of executive functioning, processing speed, and learning compared to lean controls. Abdominal obesity was associated with executive functioning deficits independent of many common medical and psychiatric factors.

Investigating whether depressed youth exhibiting elevated C reactive protein perform worse on measures of executive functioning, verbal fluency and episodic memory in a large, population based sample of Dutch adolescents

Cognitive functioning is disrupted during a depressive episode and cognitive dysfunction persists when depression is in remission. A subtype of depressed individuals who exhibit elevated inflammatory biomarkers may be at particular risk for cognitive dysfunction. We examined whether an elevated inflammatory biomarker (C-reactive protein: CRP) in acute and/or remitted depression was associated with specific deficits in executive functioning, episodic memory, and verbal fluency. Data were drawn from a population-based sample of Dutch adolescents (N = 1066; 46% male) recruited at the age of 11 and followed over the course of eight years. We tested whether adolescents with either, (i) a history of depression (Wave 1-3) or (ii) current depression (Wave 4), and elevated levels of C-reactive protein measured in blood at Wave 3 performed worse on cognitive assessments at Wave 4. Eight measures of cognitive functioning were hypothesized to load on to one of three dimensions of cognitive functioning (executive functioning, episodic memory, and verbal fluency) within a structural equation model framework. Higher levels of CRP were associated with worse future executive functioning in adolescents with and without current/prior depression. A current depression diagnosis also was associated with worse executive functioning. There was consistent evidence linking low socioeconomic status and health-related covariates (high body mass index/sedentary behavior) with worse performance across multiple measures of cognitive functioning and, importantly, the association of depression/CRP and executive functioning was no longer significant when controlling for these covariates. Future studies may benefit from investigating whether specific depressogenic behaviors (e.g., sedentary behavior/substance use) mediate a relationship between depression and worse executive functioning, potentially via a prospective pathway through elevated inflammation.

Adiposity, Inflammation, and Working Memory: Evidence for a Vicious Cycle

Overweight and obesity constitute the fifth leading cause of preventable deaths worldwide. One pathway through which excess weight contributes to poor health outcomes is via inflammatory activity and changes in cognitive processes. Prior theory has proposed a vicious cycle whereby obesity potentiates inflammatory activity, which alters cognitive processes such as working memory, which in turn leads to a reduced ability to self-regulate and therefore manage weight. However, to date no longitudinal studies have examined this potential dynamic. In the current study, we addressed this gap by assessing the relations among fat mass, C-reactive protein (CRP), and working memory across time in a large sample of 8,536 children followed through adolescence in the Avon Longitudinal Study of Parents and Children in the United Kingdom. Adiposity was quantified via dual emission x-ray absorptiometry (DEXA) at ages 9 and 15.5 years old, and inflammatory activity was indexed via circulating serum C-reactive protein (CRP) levels assessed with a high-sensitivity assay at those same ages. Working memory was assessed between these two time points, at age 10, permitting examination of the temporal relations between working memory, adiposity, and inflammatory activity. As hypothesized, we found that fat mass predicted later poor working memory, and this association was statistically mediated by CRP. Further, we found that poor working memory predicted greater subsequent fat mass and CRP, and the link between working memory and subsequent CRP was partially mediated by fat mass. These results thus could be taken to suggest the existence of a vicious cycle of mutually amplifying adiposity, inflammatory activity, and poor working memory over time.

Mitochondrial Functioning and the Relations among Health, Cognition, and Aging: Where Cell Biology Meets Cognitive Science

Cognitive scientists have determined that there is a set of mechanisms common to all sensory, perceptual, and cognitive abilities and correlated with age- and disease-related declines in cognition. These mechanisms also contribute to the development and functional coherence of the large-scale brain networks that support complex forms of cognition. At the same time, these brain and cognitive patterns are correlated with myriad health outcomes, indicating that at least some of the underlying mechanisms are common to all biological systems. Mitochondrial functions, including cellular energy production and control of oxidative stress, among others, are well situated to explain the relations among the brain, cognition, and health. Here, I provide an overview of the relations among cognitive abilities, associated brain networks, and the importance of mitochondrial energy production for their functioning. These are then linked to the relations between cognition, health, and aging. The discussion closes with implications for better integrating research in cognitive science and cell biology in the context of developing more sensitive measures of age- and disease-related declines in cognition.

Depression and worry symptoms predict future executive functioning impairment via inflammation

BACKGROUND

Scar models posit that heightened anxiety and depression can increase the risk for subsequent reduced executive function (EF) through increased inflammation across months. However, the majority of past research on this subject used cross-sectional designs. We therefore examined if elevated generalized anxiety disorder (GAD), major depressive disorder (MDD), and panic disorder (PD) symptoms forecasted lower EF after 20 months through heightened inflammation.

METHODS

Community-dwelling adults partook in this study (n = 614; MAGE = 51.80 years, 50% females). Time 1 (T1) symptom severity (Composite International Diagnostic Interview - Short Form), T2 (2 months after T1) inflammation serum levels (C-reactive protein, fibrinogen, interleukin-6), and T3 (20 months after T1) EF (Brief Test of Adult Cognition by Telephone) were assessed. Structural equation mediation modeling was performed.

RESULTS

Greater T1 MDD and GAD (but not PD) severity predicted increased T2 inflammation (Cohen's d = 0.21-1.92). Moreover, heightened T2 inflammation forecasted lower T3 EF (d = -1.98 to -1.87). T2 inflammation explained 25-32% of the negative relations between T1 MDD or GAD and T3 EF. T1 GAD severity predicting T3 EF via T2 inflammation path was stronger among younger (v. older) adults. Direct effects of T1 MDD, GAD, and PD forecasting decreased T3 EF were found (d = -2.02 to -1.92). Results remained when controlling for socio-demographic, physical health, and lifestyle factors.

CONCLUSIONS

Inflammation can function as a mechanism of the T1 MDD or GAD-T3 EF associations. Interventions that successfully treat depression, anxiety, and inflammation-linked disorders may avert EF decrements.

Central Obesity, Cardiometabolic Risk, and Cognitive Change in the Study of Latinos - Investigation of Neurocognitive Aging

BACKGROUND

The relationships between obesity and cognitive decline in aging are mixed and understudied among Hispanics/Latinos.

OBJECTIVE

To understand associations between central obesity, cognitive aging, and the role of concomitant cardiometabolic abnormalities among Hispanics/Latinos.

METHODS

Participants included 6,377 diverse Hispanics/Latinos enrolled in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and SOL-Investigation for Neurocognitive Aging (SOL-INCA). Participants were 45 years and older at the first cognitive testing session (Visit 1). Cognitive outcomes (z-score units) included global composite and domain specific (learning, memory, executive functioning, processing speed) measures at a second visit (SOL-INCA, on average, 7 years later), and 7-year change. We used survey linear regression to examine associations between central obesity (waist circumference≥88 cm and≥102 cm for women and men, respectively) and cognition. We also tested whether the relationships between obesity and cognition differed by cardiometabolic status (indication of/treatment for 2 + of the following: high triglycerides, hypertension, hyperglycemia, low high-density lipoprotein cholesterol).

RESULTS

Central obesity was largely unassociated with cognitive outcomes, adjusting for covariates. However, among individuals with central obesity, cardiometabolic abnormality was linked to poorer cognitive function at SOL-INCA (ΔGlobalCognition =-0.165, p < 0.001) and to more pronounced cognitive declines over the average 7 years (ΔGlobalCognition = -0.109, p < 0.05); this was consistent across cognitive domains.

CONCLUSION

Central obesity alone was not associated with cognitive function. However, presence of both central obesity and cardiometabolic abnormalities was robustly predictive of cognition and 7-year cognitive declines, suggesting that in combination these factors may alter the cognitive trajectories of middle-aged and older Hispanics/Latinos.

Mitochondrial Functions, Cognition, and the Evolution of Intelligence: Reply to Commentaries and Moving Forward

In response to commentaries, I address questions regarding the proposal that general intelligence (g) is a manifestation of the functioning of intramodular and intermodular brain networks undergirded by the efficiency of mitochondrial functioning (Geary 2018). The core issues include the relative contribution of mitochondrial functioning to individual differences in g; studies that can be used to test associated hypotheses; and, the adaptive function of intelligence from an evolutionary perspective. I attempt to address these and related issues, as well as note areas in which other issues remain to be addressed.

C-Reactive Protein as a Possible Predictor of Trail-Making Performance in Individuals with Psychiatric Disorders

Cognitive dysfunction is a prominent feature of psychiatric disorders. Studies have shown that systemic low-grade inflammation is crucial in the development of cognitive deficits across psychiatric disorders. The aim of this study was to further examine the role of inflammation and inflammatory mediators in cognitive function in psychiatric disorders. This study included 364 inpatients (53% females) with International Classification of Diseases (ICD)-10 F3 (affective disorders) and F4 (neurotic, stress-related, and somatoform disorders) diagnoses. The mean age was 52 years (22 to 69 years) and the median body mass index was 27.6. Cognitive function was assessed with the Color–Word Interference Test after Stroop and the Trail-Making Test A/B. Multiple linear regression models were calculated to assess the predictive value of C-reactive protein and the kynurenine/tryptophan ratio on cognitive function controlling for age, sex, education, premorbid verbal intelligence quotient, illness duration, depressive symptoms, and obesity-related parameters (e.g., body mass index, high-density lipoprotein). Our data confirm that in patients with psychiatric disorders, C-reactive protein serum concentration is a relevant and important predictor of Trail-Making Test B performance, measuring cognitive flexibility. The effect size of this association did not change much after adding clinical and metabolic variables into the regression model. The kynurenine/tryptophan ratio was not related to cognitive test scores. The involvement of C-reactive protein as a peripheral inflammatory marker in cognitive flexibility and psychomotor processing speed in psychiatric illness can be concluded.

The role of prebiotics in cognition, anxiety, and depression

The disruption of the gut microbial composition, defined as dysbiosis, has been associated with many neurological disorders with inflammatory components. The alteration of the gut microbiota leads to an increase in pro-inflammatory cytokines that are associated with metabolic diseases (such as obesity and type 2 diabetes), autoimmune arthritis, and neuropsychiatric diseases. Prebiotics are defined as non-digestible carbohydrates and promote the growth of beneficial bacteria such as bifidobacteria and lactobacillus, exert beneficial effects on improving dysbiosis and its associated inflammatory state. Preclinical and clinical data indicated that some prebiotics also have positive impacts on the central nervous system (CNS) due to the modulation of neuroinflammation and thus may have a key role in the modulation of cognitive impairment, anxiety, and depression. The present manuscript reviews the state-of-art of the effects of prebiotics in cognitive impairment, anxiety, and depressive disorders. Data from clinical studies are still scarce, and further clinical trials are needed to corroborate the potential therapeutic cognitive, antidepressant, and anxiolytic of prebiotics. Prebiotics may provide patients suffering from cognitive deficits, depression, and anxiety with a new tool to minimize disease symptoms and increase the quality of life.

Executive dysfunction in depression in adolescence: the role of inflammation and higher body mass

BACKGROUND

There is substantial evidence that many depressed individuals experience impaired executive functioning. Understanding the causes of executive dysfunction in depression is clinically important because cognitive impairment is a substantial contributor to functional impairment. This study investigated whether elevated levels of an inflammatory cytokine [interleukin-6 (IL-6)] and/or higher body mass index (BMI) concurrently and/or prospectively accounted for the relationship between depressive symptoms and impaired executive functioning in adolescents.

METHODS

A diverse, community sample of adolescents (N = 288; mean age = 16.33; 51.4% female; 59.0% African-American) completed assessments of height and weight, IL-6, depressive symptoms, and self-report/behavioral measures of executive functioning (selective attention, switching attention) and future orientation annually over 3 years. Adolescents experiencing acute illness or medical conditions that affect inflammation were excluded from analyses. Path analysis within a structural equation modeling framework simultaneously examined the concurrent and prospective relationships between BMI, IL-6, depressive symptoms, and the measures of cognitive functioning across three timepoints.

RESULTS

Across all timepoints, higher BMI was prospectively associated with higher levels of IL-6 and depressive symptoms, while higher levels of IL-6 were associated with worse performance on three behavioral and self-report measures of cognitive functioning. Higher depressive symptoms also were prospectively associated with elevated IL-6 and both higher depressive symptoms and a higher BMI predicted worse future executive functioning via increased IL-6.

CONCLUSIONS

More severe depressive symptoms and increased BMI may disrupt executive functioning via elevated IL-6.

The association between obesity and lower working memory is mediated by inflammation: Findings from a nationally representative dataset of U.S. adults

Obesity is often accompanied by lower working memory (e.g., a lower ability to keep goal-relevant information in mind) relative to healthy weight individuals. Understanding this relative working memory impairment has important clinical implications, as working memory is thought to facilitate adherence to weight management programs. Theoretical models of obesity, self-regulation, and inflammation suggest that inflammation plays a role in obesity-related working memory impairments, but to date no study has tested this prediction. Therefore, the current study examined whether inflammation statistically mediated the relationship between obesity and working memory in a nationally representative dataset of U.S. adults from Wave IV of The National Longitudinal Study of Adolescent to Adult Health (N = 11,546, age range 25-34). Inflammation was quantified via C-reactive protein (CRP) level, and working memory was assessed using a modified digit span backward task. As expected, cross-sectional analyses showed that a body mass index (BMI) indicative of obesity-as well as greater BMI when BMI was analyzed continuously-and greater CRP were each related to lower working memory. Critically, we found that CRP levels statistically mediated the relationships between obesity/greater BMI and working memory, with CRP accounting for 44.1% of the variance explained in working memory by BMI. Moreover, these findings held both with and without controlling for relevant covariates, including demographic characteristics (e.g., age), socioeconomic status, and behavioral factors (e.g., smoking). Our results therefore point to inflammation as playing an important role in the relationship between obesity and working memory, and suggest that interventions aimed at reducing inflammation may help lessen the cognitive burden of obesity.

Altered neural correlates of episodic memory in adolescents with severe obesity

Negative effects of obesity on memory and associated medial temporal circuitry have been noted in animal models, but the status in humans, particularly children, is not well established. Our study is the first to examine neural correlates of successful memory encoding of visual scenes and their associated context in adolescents with severe obesity (age 14-18 years, 43% male). Despite similar subsequent memory as adolescents without obesity (BMI for age and sex <95th percentile), those with severe obesity (BMI for age and sex 120% above the 95th percentile) showed reduced hippocampal, parahippocampal, frontal, and parietal engagement during encoding of remembered visual scenes and greater lateral temporal engagement during encoding of their associated context. Standardized testing revealed a trend level group difference in memory performance, with a larger magnitude of obesity-related difference in recollection-related memory that was mediated by individual differences in lateral temporal activation during contextual encoding. The observed widespread functional alterations are concerning in light of the importance of mnemonic processing for academic achievement and feeding behavior and underscore the need for prevention and intervention initiatives for pediatric obesity.

Effects of adiposity and metabolic dysfunction on cognition: A review

Obesity and metabolic dysfunction are both correlated with increased rates of cognitive decline. However, because these two conditions often co-occur, it remains unclear whether their cognitive consequences are independent. In this review, we carefully consider literature examining the effects of metabolic dysfunction and increased adiposity on cognition across the lifespan, including only well-controlled studies that attempt to dissociate their effects. We found a total of 36 studies, 17 examining metabolic dysfunction and 19 examining the effects of adiposity. We found evidence from the literature suggesting that increased adiposity and metabolic dysfunction may contribute to deficits in executive function, memory, and medial temporal lobe structures largely independent of one another. These deficits are thought to arise principally from physiological changes associated with inflammation, vascularization, and oxidative stress, among others. Such processes may result from excess adipose tissue and insulin resistance that occur independently and can further exacerbate when the two conditions co-occur. However, we also find it likely that impaired cognition plays a role in behavioral and lifestyle choices that lead to increased adiposity and metabolic dysfunction, which can then perpetuate and augment cognitive decline. We recommend additional prospective and longitudinal studies to examine whether impaired cognition is a cause and/or consequence of these factors.

Anti-diabetic effect of oligosaccharides from seaweed Sargassum confusum via JNK-IRS1/PI3K signalling pathways and regulation of gut microbiota

Brown seaweed Sargassum confusum (C. Agardh) has been used in traditional Chinese medicine to treat a variety of diseases. The aim of the present study was to evaluate the anti-diabetic effect of oligosaccharides from brown seaweed S. confusum (SCO). The anti-diabetic effect of SCO was evaluated in vivo using high-fat/high-sucrose fed hamsters. Molecular mechanisms of modulating gene expression of specific members of insulin signaling pathways were determined. The components of the intestinal microflora in diabetic animals were also analyzed by high-throughput 16S rRNA gene sequencing. And it was found that SCO had a sequence of sulfated anhydrogalactose and methyl sulfated galactoside units. Fasting blood glucose levels were significantly decreased after SCO administration. Histology showed that SCO could protect the cellular architecture of the liver. SCO could also significantly increase the relative abundance of Lactobacillus and Clostridium XIVa and decrease that of Allobaculum, Bacteroides and Clostridium IV. The active role of SCO in anti-diabetic effect was revealed by its regulation of insulin receptor substrate 1/phosphatidylinositol 3-kinase and c-Jun N-terminal kinase pathways. These results suggested that SCO might be used as a functional material to regulate gut microbiota in obese and diabetic individuals.

A Preliminary Cohort Study Assessing Routine Blood Analyte Levels and Neurological Outcome after Spinal Cord Injury

There is increasing interest in the identification of biomarkers that could predict neurological outcome following a spinal cord injury (SCI). Although initial American Spinal Injury Association (ASIA) Impairment Scale (AIS) grade is a good indicator of neurological outcome, for the patient and clinicians, an element of uncertainty remains. This preliminary study aimed to assess the additive potential of routine blood analytes following principal component analysis (PCA) to develop prognostic models for neurological outcome following SCI. Routine blood and clinical data were collected from SCI patients (n = 82) and PCA used to reduce the number of blood analytes into related factors. Outcome neurology was obtained from AIS scores at 3 and 12 months post-injury, with motor (AIS and total including all myotomes) and sensory (AIS, touch and pain) abilities being assessed individually. Multiple regression models were created for all outcome measures. Blood analytes relating to “liver function” and “acute inflammation and liver function” factors were found to significantly increase prediction of neurological outcome at both 3 months (touch, pain, and AIS sensory) and at 1 year (pain, R² increased by 0.025 and total motor, R² increased by 0.016). For some models “liver function” and “acute inflammation and liver function” factors were both significantly predictive, with the greatest combined R² improvement of 0.043 occurring for 3 month pain prediction. These preliminary findings support ongoing research into the use of routine blood analytes in the prediction of neurological outcome in SCI patients.

Allostatic load and executive functions in overweight adults

BACKGROUND/OBJECTIVE

Overweight is linked to inflammatory and neuroendocrine responses potentially prompting deregulations in biological systems harmful to the brain, particularly to the prefrontal cortex. This structure is crucial for executive performance, ultimately supervising behaviour. Thus, in the present work, we aimed to test the relationship between allostatic load increase, a surrogate of chronic physiological stress, and core executive functions, such as cognitive flexibility, inhibitory control, and working memory.

METHOD

Forty-seven healthy-weight and 56 overweight volunteers aged from 21 to 40 underwent medical and neuropsychological examination.

RESULTS

Overweight subjects exhibited a greater allostatic load index than healthy-weight individuals. Moreover, the allostatic load index was negatively related to inhibitory control. When separated, the link between allostatic load index and cognitive flexibility was more marked in the overweight group.

CONCLUSIONS

An overweight status was linked to chronic physiological stress. The inverse relationship between the allostatic load index and cognitive flexibility proved stronger in this group. Set-shifting alterations could sustain rigid-like behaviours and attitudes towards food.

Psychological Factors and Cardiovascular Disease Risk Factors as Mediators of the Relationship between Overweight/Obesity and Cognitive Function among School Children in Kuala Lumpur, Malaysia

BACKGROUND

Recent research suggests that a negative relationship exists between adiposity and cognitive function in children. However, limited information is known on how they are related. This study aimed to examine the mediators of the relationship between overweight/obesity and cognitive function among school children in Kuala Lumpur, Malaysia.

METHODS

This is a cross-sectional comparison study whereby 225 overweight/obese children matched for age, sex, and ethnicity with 225 normal weight children participated in this study. Body image dissatisfaction, disordered eating, and depressive symptoms were assessed through a self-administered questionnaire. Blood pressure was measured, whereas blood was drawn to determine insulin, high-sensitivity C-reactive protein (hs-CRP), glucose, and lipid profiles. Homeostasis model assessment-estimated insulin resistance (HOMA-IR) was calculated using glucose and insulin levels. Wechsler's Intelligence Scale for Children-Fourth Edition (WISC-IV) was used to assess cognitive function in children. Ordinary least square regression analysis was conducted to determine the direct and indirect relationships between weight status and cognitive function.

RESULTS

A negative relationship was found between overweight/obesity with cognitive function. Overweight/obese children were on average 4.075 units lower in cognitive function scores compared to normal weight children. Such difference was found through mediators, such as body image dissatisfaction, disordered eating, depression, systolic blood pressure, triglycerides, HOMA-IR, and hs-CRP, contributing 22.2% of the variances in cognitive function in children.

CONCLUSION

Results highlight the important mediators of the relationship between overweight/obesity and cognitive function. Consequently, future interventions should target to improve psychological well-being and reduce cardiovascular disease risk for the prevention of poorer cognitive performance in overweight/obese children.