Relationship between Central Obesity and the incidence of Cognitive Impairment and Dementia from Cohort Studies Involving 5,060,687 Participants

Association of Predicted Visceral Fat Percentage With Dementia Risk in Older Adults: The Role of Genetic Risk and Lifestyle

BACKGROUND AND OBJECTIVES

Obesity is a modifiable dementia risk factor, but body mass index does not account for fat distribution, particularly visceral fat, which is more strongly linked to metabolic and cardiovascular health. Despite its relevance, research on visceral fat and dementia is limited, especially in large-scale prospective studies. The aim of this study was to assess the association between visceral fat and dementia risk, its interaction with genetic predisposition, and the impact of healthy lifestyle adherence.

METHODS

Using data from the UK Biobank (UKB) cohort, we computed baseline, sex-specific visceral fat percentage (VFP), defined as the ratio of visceral fat mass to total body fat mass. Nonlinear associations between VFP and incident dementia were initially assessed using restricted cubic splines. The relationship between VFP and incident dementia was further examined using Cox proportional hazard models. In addition, stratified and interaction analyses were conducted to assess dementia incidence across VFP levels, lifestyle factors, and genetic risk.

RESULTS

The study included 63,042 women (mean age: 63.96 years) and 74,001 men (64.20 years) aged 60 years and older from the UKB, with a median follow-up of 14.07 years for men and 14.09 years for women. During follow-up, 2,805 men and 1,893 women developed dementia. A U-shaped association between VFP and dementia risk was observed in both sexes. In men, each SD increase in VFP below the median value of 8.1% was associated with a reduced risk of dementia (HR: 0.90, 95% CI 0.85-0.96), whereas above the median, the risk increased (1.06, 1.00-1.11). Similarly, in women, below the median VFP value of 3.1%, each SD increase was linked to a decreased dementia risk (0.89, 0.83-0.96), and above the median, the risk increased (1.14, 1.07-1.22). No significant interactions were found between VFP and genetic risk or lifestyle factors.

DISCUSSION

Among nondemented, community-dwelling older Britons, atypical VFP was associated with higher dementia risk in both sexes. The lack of interaction between VFP and genetic risk highlights the complexity of dementia pathogenesis. In addition, a healthy lifestyle may mitigate the dementia risk associated with atypical VFP levels.

Astrocyte-derived extracellular vesicular NFIA mediates obesity-associated cognitive impairment

BACKGROUND

The escalating global prevalence of cognitive decline associated with obesity represents a significant public health challenge. Emerging evidence implicates astrocyte-derived extracellular vesicles (ADEVs) as key mediators in the pathogenesis of neurodegenerative disease, positioning them as potential therapeutic targets. However, the precise mechanistic role of ADEVs in the pathological processes underlying obesity-related cognitive impairment remains poorly understood.

METHODS

We established an obese mouse model by feeding mice a 60% high-fat diet (HFD) and assessed cognitive function through a series of behavioral tests. To investigate the role of extracellular vesicles (EVs), we inhibited EVs secretion by intraperitoneally administering GW4869, a neutral sphingomyelinase-2 (nSMase2) inhibitor, to 12-week HFD-fed male mice. Using comprehensive proteomic sequencing of brain-derived EVs, we identified NFIA as a potentially candidate protein. A series of in vivo and in vitro experiments were then conducted to confirmed the astrocytic origin of NFIA and neuronal uptake of ADEVs. Further, ADEVs isolated from primary cultured astrocytes under high glucose conditions were administered to both wild-type mice and primary cultured neurons to demonstrate their mediating role. Additionally, we developed adeno-associated virus (AAV) constructs to specifically knockdown the target gene Nfia of astrocyte to validate these findings.

RESULTS

Following 16 weeks of HFD feeding, obese mice exhibited significant cognitive impairment, which was significantly alleviated by GW4869 administration through inhibition of ceramide-dependent EVs secretion. Proteomic analysis revealed a marked upregulation of NFIA protein in brain-derived EVs from obese mice, with astrocytes identified as the predominant cellular origin. ADEVs containing NFIA has been found to specifically accumulated in the hippocampal neurons both in vivo and in vitro. As expected, ADEVs isolated from high glucose-treated primary astrocytes induced substantial cognitive decline in healthy adult mice and caused synaptic injury in primary cultured neurons. Of note, astrocyte-specific knockdown of the Nfia gene resulted in improved synaptic function and ameliorated cognitive impairment in obese mice.

CONCLUSIONS

These findings demonstrated that elevated levels of NFIA packaged within ADEVs contributed to hippocampal synaptic injury under obesity-induced stress condition. The mechanistic insight may provide potential therapeutic targets for addressing obesity-related cognitive decline.

Cardiovascular risk and obesity impact loss of grey matter volume earlier in males than females

BACKGROUND

It remains imperative to discover the time course that cardiovascular risk factors influence neurodegeneration in males and females and decipher whether the apolipoprotein (APOE) genotype mediates this relationship. Here we perform a large-scale evaluation of the influence of cardiovascular risk and obesity on brain volume in males and females in different age groups.

METHODS

34 425 participants between the ages of 45 and 82 years were recruited from the UK Biobank database https://www.ukbiobank.ac.uk. T1-weighted structural MR images (n=34 425) were downloaded locally for all participants, and voxel-based morphometry was performed to characterise the volumetric changes of the whole brain. The influence of Framingham cardiovascular risk (general cardiovascular risk), abdominal subcutaneous adipose tissue, and visceral adipose tissue volume (obesity) on cortical grey matter volume across different decades of life was evaluated with voxel-wise analysis.

RESULTS

In males, cardiovascular risk and obesity demonstrated the greatest influence on lower grey matter volume between 55-64 years of age. Female participants showed the greatest effect on lower grey matter volume between 65-74 years of age. Associations remained significant in APOE ε4 carriers and APOE ε4 non-carriers when evaluated separately.

CONCLUSIONS

The strongest influence of cardiovascular risk and obesity on reduced brain volume was between 55-64 years of age in males, whereas women were most susceptible to the detrimental effects of cardiovascular risk a decade later between 65-74 years of age. Here we elucidate the timing that targeting cardiovascular risk factors and obesity should be implemented in males and females to prevent neurodegeneration and Alzheimer's disease development.

Causal cardiovascular risk factors for dementia: insights from observational and genetic studies

The escalating prevalence of dementia worldwide necessitates preventive strategies to mitigate its extensive health, psychological, and social impacts. As the prevalence of dementia continues to rise, gaining insights into its risk factors and causes becomes paramount, given the absence of a definitive cure. Cardiovascular disease has emerged as a prominent player in the complex landscape of dementia. Preventing dyslipidaemia, unhealthy western-type diets, hypertension, diabetes, being overweight, physical inactivity, smoking, and high alcohol intake have the potential to diminish not only cardiovascular disease but also dementia. The purpose of this review is to present our current understanding of cardiovascular risk factors for Alzheimer's disease and vascular dementia (VaD) by using clinical human data from observational, genetic studies and clinical trials, while elaborating on potential mechanisms. Hypertension and Type 2 diabetes surface as significant causal risk factors for both Alzheimer's disease and VaD, as consistently illustrated in observational and Mendelian randomization studies. Anti-hypertensive drugs and physical activity have been shown to improve cognitive function in clinical trials. Important to note is that robust genome-wide association studies are lacking for VaD, and indeed more and prolonged clinical trials are needed to establish these findings and investigate other risk factors. Trials should strategically target individuals at the highest dementia risk, identified using risk charts incorporating genetic markers, biomarkers, and cardiovascular risk factors. Understanding causal risk factors for dementia will optimize preventive measures, and the implementation of well-known therapeutics can halt or alleviate dementia symptoms if started early. Needless to mention is that future health policies should prioritize primordial prevention from early childhood to prevent risk factors from even occurring in the first place. Together, understanding the role of cardiovascular risk factors in dementia, improving genome-wide association studies for VaD, and advancing clinical trials are crucial steps in addressing this significant public health challenge.

The obesity paradox in cognitive decline: Impact of BMI dynamics and APOE genotypes across various cognitive status

AIMS

To explore the relationship between body mass index (BMI) and its changes in relation to cognitive decline across different cognitive status, while also examining the role of the APOE genotype in these associations.

MATERIALS AND METHODS

A total of 23 255 individuals from the National Alzheimer's Coordinating Center (NACC) were analysed using multivariable logistic and Cox regression to assess BMI and its variability in relation to cognitive decline. Subgroup analyses were conducted to explore how APOE genotype interacts with BMI and cognitive decline.

RESULTS

Compared to individuals with normal cognition and normal BMI, being underweight was associated with a higher risk of developing MCI (HR 3.065, 95% CI: [1.156-8.126]) and dementia (HR 4.057, 95% CI: [1.433-11.483]). Over the 4.07-year follow-up, 9171 individuals experienced cognitive decline. Longitudinal analysis revealed that being overweight or obese was linked to a lower risk of cognitive decline across different cognitive status, including impaired not MCI, MCI and dementia, but had no effect on those with normal cognition. Additionally, compared to stable BMI, the hazard ratios (95% CI) for developing dementia were 2.336 (2.128-2.565) and 2.338 (2.119-2.581) for annual BMI gain or loss greater than 5%. However, different APOE genotypes may influence the effect of BMI and BMI variability on cognitive decline.

CONCLUSIONS

This research supports the 'obesity paradox' and highlights the critical role of APOE in modulating BMI's influence on cognitive health.

Estimating global prevalence of mild cognitive impairment and dementia in elderly with overweight, obesity, and central obesity: A systematic review and meta-analysis

BACKGROUND AND AIM

Previous studies have demonstrated that adiposity, particularly obesity during midlife, may have a detrimental effect on cognitive function. This study aims to estimate the global prevalence of mild cognitive impairment (MCI) and dementia in elderly aged 60 years or above with overweight, obesity, and central obesity.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library from inception to November 2023. DerSimonian-Laird random-effects model with Logit transformation was used. Sensitivity analysis, meta-regression, and subgroup analysis were employed to investigate determinants of the prevalence of MCI and dementia.

RESULTS

A total of 72 studies involving 2,980,947 elderly with distinct adiposity status were included. Pooled prevalence of MCI and dementia in elderly with overweight and obesity was 32.54% and 9.47%, respectively. Univariate meta-regression analysis indicated that the heterogeneity in dementia prevalence was attributable to variations in study size (R2 = 0.01, p < 0.05), while the multivariable analysis underscored that the income of country or area had the most significant predictive importance (60.3% and 90.3%) for both MCI and dementia prevalence. Subgroup analysis revealed regional disparities and diagnostic technique variations contributing to heterogeneity. Based on currently available but inadequate epidemiological data, the pooled prevalence of MCI and dementia in elderly with central obesity was calculated as 10.18% and 9.75%, respectively.

CONCLUSION

Strategies to address adiposity-associated cognitive impairment should consider multifaceted interventions beyond simple weight reduction. Macro-level initiatives such as improvement of income levels and micro-level interventions including the adoption of accurate diagnostic techniques also represent equally pivotal components.

Severe obesity and menopause symptoms are associated with cognitive impairment in postmenopausal women from Latin America

OBJECTIVE

This study aimed to evaluate the association between obesity and cognitive impairment.

METHODS

This study is a sub-analysis of an observational, cross-sectional study in nine Latin American counties. Sociodemographic, clinical and anthropometric data were collected, and cognition was assessed using the Montreal Cognitive Assessment (MoCA) tool in 722 postmenopausal women.

RESULTS

The mean age, body mass index (BMI) and years of education of the cohort were 56.9 years, 26.8 kg/m2 and 13.6 years, respectively. Women with cognitive impairment, compared to those without, had a higher BMI (27.8 ± 5.9 vs. 26.6 ± 4.9 kg/m2, p = 0.037), had more children (3.1 ± 2.4 vs. 2.5 ± 1.7, p = 0.023), experienced more severe menopausal symptoms (56.3% vs. 31.9%, p < 0.001) and presented more comorbidities (60.0% vs. 43.8%, p = 0.006). They also had fewer years of study (10.8 ± 5.1 vs. 13.9 ± 4.9 years, p = 0.001), were less physically active (35.0% vs. 49.1%, p = 0.018) and were less likely to use menopausal hormone therapy (MHT) (11.3% vs. 28.8%, p = 0.001). In binary logistic regression analysis, BMI ≥ 35.0 kg/m2 (odds ratio [OR] 2.27, 95% confidence interval [CI] 1.08-4.76) and severe menopausal symptoms (OR 2.10, 95% CI 1.29-3.43) were associated with cognitive impairment. In the model, factors related to lower risk were ever use of MHT (OR 0.44, 95% CI 0.21-0.92) and having more years of education (OR 0.38, 95% CI 0.20-0.64).

CONCLUSION

Severe obesity and severe menopausal symptoms increased the risk of cognitive impairment in postmenopausal women, while higher education and ever use of MHT were protective factors.

Impact of obesity on neuropsychiatric symptoms in Alzheimer's disease: Insights from the ADNI cohort

BackgroundObesity is a major global health issue linked to increased risks of dementia, including Alzheimer's disease (AD). While the association between obesity and neuropsychiatric symptoms (NPS) in AD remains underexplored, identifying these links could aid in weight management in AD patients.ObjectiveThis study investigates the relationship between body mass index (BMI) and NPS in AD dementia patients, focusing on the potential mediating role of systemic inflammation.MethodsWe employed Generalized Additive Models (GAMs) to explore the relationship between BMI and NPS, as measured by the Neuropsychiatric Inventory Questionnaire (NPI-Q). Participants were classified into ideal, overweight, and obese groups based on WHO criteria. Longitudinal analyses assessed the trajectory of NPI-Q scores in different groups over a one-year follow-up.ResultsBMI significantly affects NPI-Q total scores and specific symptoms, including delusions, hallucinations, agitation/aggression, elation/euphoria, disinhibition, irritability/lability, aberrant motor behavior, nighttime disturbances, and appetite/eating disturbances. Obese patients exhibited higher NPI-Q total scores and greater severity in symptoms such as hallucinations, agitation/aggression, elation/euphoria, apathy/indifference, disinhibition, aberrant motor behavior, and nighttime disturbances. Additionally, CRP and complement C3 were identified as mediators in the relationship between obesity and NPS, highlighting the role of systemic inflammation.ConclusionsThis study demonstrates that obesity is associated with a heightened burden of NPS in AD dementia patients. The identification of CRP and complement C3 as mediators suggests inflammation plays a crucial role in the association between obesity and NPS. These findings underscore the importance of addressing obesity and its inflammatory consequences in managing NPS among this vulnerable population.

Sex differences in body mass index and waist circumference trajectories and dementia risk: the HUNT4 70+ study

We examined associations between body mass index (BMI), waist circumference (WC), and dementia risk, and differences in BMI and WC trajectories before dementia diagnosis. We included 9,739 participants (54% women) aged 70+ from the Trøndelag Health Study (HUNT4 70+). BMI was measured four times (1984-2019) and WC three times (1995-2019). Dementia diagnoses were clinically assessed at HUNT4 70+ . Women and men with dementia had higher midlife BMI and WC than those without dementia. These differences diminished closer to diagnosis, especially in women. Midlife obesity in both sexes and midlife overweight, high WC, and overweight/obesity with high WC in men were linked to higher dementia risk. Lower dementia risk was observed with late-life overweight for both sexes, late-life high WC in women, late-life overweight/obesity with normal WC in men or high WC in women. Adiposity measures and their changes influence dementia risk differently in women and men.

Depression reduces cognitive function partly through effects on BMI and hypertension: a large observational study and Mendelian randomization analysis

BACKGROUND

While abundant evidence suggests a correlation between depression and the risk of cognitive impairments, the causal relationship, as well as the mechanisms mediating this association, remain uncertain.

METHODS

We conducted an observational study within the National Health and Nutrition Examination Survey (NHANES), simultaneously employing weighted multivariable-adjusted linear regression to explore the association between them. Subsequently, Mendelian randomization analysis was employed to investigate the causal relationship between them as well as the mediating effects.

RESULTS

The observational analysis of NHANES data indicates that depression is independently associated with cognitive function. Regarding MR, genetically predicted depression is causally related to cognitive function in the IVW method (OR 0.33, 95% CI 0.14-0.78, P = 0.012). Furthermore, depression leads to obesity (OR = 1.91, P = 2.53 × 10 - 3) and elevated blood pressure (OR 2.34, P = 3.62 × 10 - 3). Waist circumference (OR = 0.85, P = 3.00 × 10 - 4), BMI (OR = 0.84, P = 1.06 × 10 - 6), and hypertension (OR = 0.95, P = 4.00 × 10 - 3) all contribute to cognitive function. Additionally, there is no causal association between cognitive function and depression (OR 1.00, 95% CI 0.99-1.01, P = 0.559) in reverse Mendelian randomization. Mediation analysis indicates that BMI and hypertension mediate 9.9% and 3.6% of the cognitive function under depression conditions, respectively.

CONCLUSIONS

Our study indicates that depression can lead to obesity and hypertension, which can reduce cognitive function. These findings underscore the importance of timely identification and management of depression in patients with cognitive impairments and suggest that treatments aimed at reducing weight and lowering blood pressure may help prevent cognitive impairment.

Associated factors and gender differences of falls in older adults with hypertension: a national cross-sectional survey

Background

Falls have become a crucial public health problem among older adults, especially those with hypertension. However, the current understanding of the risk of falls among them is still insufficient. The purpose of this study was to investigate the factors associated with falls and their gender differences among older adults with hypertension in China.

Methods

Based on the cross-sectional data of the Chinese Longitudinal Healthy Longevity Survey (CLHLS) 2018 database, this study defined 24 possible associated factors based on the five dimensions of the Health Ecology Model. Binary Logistic Regression Model was used to analyze the impact of each factor on falls among older adults with hypertension.

Results

The prevalence rate of falls in older adults with hypertension in China was 22.60%. Falls are associated with a variety of factors. Specifically, gender, self-rated health, hearing impairment, stroke, instrumental activities of daily living (IADL) disability, basic activities of daily living (BADL) disability, exercise, fresh fruit and taste preference are significant associated factors for falls among older adults with hypertension. Among them, the effects of self-rated health, stroke and exercise on falls are only significant in female with hypertension. The effect of fresh fruit on falls was significant only in men with hypertension.

Conclusion

The findings highlight that the current situation of falls among older adults with hypertension requires attention, necessitating comprehensive measures for prevention and control.

Association between abdominal obesity and cognitive decline among Chinese middle-aged and older adults: a 10-year follow-up from CHARLS

Introduction

The relationship between abdominal obesity and cognitive decline has controversial results, and the mediating effect of high-density lipoprotein cholesterol (HDL-C) between them remains uncertain. This study aims to explore the association between abdominal obesity and cognitive decline in middle-aged and older adults, including dose-response relationship and age differences, as well as the mediating effect of HDL-C.

Methods

Data were obtained from the China Health and Retirement Longitudinal Study (CHARLS), involving 3,807 participants aged 45 and above from 2010 to 2020. The TICS-10 was used to assess cognitive function, and the group-based trajectory model (GBTM) was used to explore the potential heterogeneity of cognitive changes. Abdominal obesity was measured by baseline waist circumference (WC) and a sequentially adjusted unordered multinomial logistic regression was used to investigate the association between abdominal obesity and cognitive decline in middle-aged and older adults. Restricted cubic spline (RCS) model was adopted to analyze the dose-response relationship between WC and risk of cognitive decline. HDL-C was used as a mediator to examine the potential causal chain between abdominal obesity and cognitive decline.

Results

Among the 3,807 participants, a total of 1,631 individuals (42.84%) had abdominal obesity. The GBTM identified 3 cognitive function trajectories: rapid decline (11.0%), slow decline (41.1%) and stable groups (47.9%). After controlling for confounders, participants with abdominal obesity were less likely to experience rapid decline (OR: 0.67, 95%CI: 0.51-0.8) and slow decline (OR: 0.81, 95%CI: 0.69-0.95) of cognitive function, compared to those with normal WC. RCS analysis showed a decreased risk of cognitive decline with increasing WC. In the age subgroup analysis, the protective effect was significant only in the population aged 50 and above. HDL-C mediated 19.15% (P < 0.05) of the relationship between abdominal obesity and cognitive decline.

Conclusion

Abdominal obesity had a significant protective effect on cognitive decline in Chinese middle-aged and older adults, with HDL-C playing a mediating role in the relationship between abdominal obesity and cognitive decline.

Role of obesity-related anthropometric indicators on cognitive function in obese older adults: A systematic review and meta-analysis

OBJECTIVES

The association between obesity and cognitive function in older adults remains inconsistent due to the use of various anthropometric indicators, such as body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR). More conclusive evidence is warranted. The aim of this study was to systematically summarize and synthesize the association between specific obesity-related anthropometric indicators (BMI, WC, and WHR) and cognitive function in obese older adults. Higher BMI, WC, or WHR is linked to cognitive decline in this population.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

A comprehensive literature search was carried out using PubMed, CINAHL, Scopus, Embase, and the Cochrane Library (from their inception to October 2023). Studies investigating the association between obesity indicators, including BMI, WC, WHR, and cognitive performance in older adults were included. The weighted mean difference (WMD), Odds Ratio, and 95 % confidence interval (CI) were used to estimate the pooled effect size. A random-effects model was employed as the main method. Subgroup analyses and the certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach were assessed (registered number: CRD42023461770).

RESULTS

Thirty-three eligible studies, involving 83,251 participants, were included. Obese older adults, as assessed by WC, had lower Mini-Mental State Examination (MMSE) scores than non-obese counterparts (WMD -0.84, 95 % CI -1.64 to -0.05, very low certainty). Those measured by WHR had a 31 % higher risk of cognitive impairment (OR 1.31, 95 % CI 1.12 to 1.53, moderate certainty). Subgroup analysis revealed a lower Montreal Cognitive Assessment (MoCA) score in obese group classified by WHO criteria compared to controls (WMD -1.67, 95 % CI -2.94 to -0.39).

CONCLUSION

This review suggests an association between obesity, as measured by WHR and WC, and poorer cognitive performance in older adults. WHR is moderately recommended for identifying cognitive impairment-related obesity, while WC recommendations are limited by very low evidence certainty.

Effects of Digital Neurohabilitation on Attention and Memory in Patients with a Diagnosis of Pediatric Obesity: Case Series

Objective: Obesity represents a health risk and several studies have linked this clinical entity to cognitive deficits. Among the neuropsychological rehabilitation tools, Peak, a digital application, has shown positive results as a therapeutic method. The aim of this work was to measure, for the first time, cognitive deficits and the effects of Peak digital cognitive neurohabilitation therapy in patients diagnosed with obesity. Methods: Peak treatment was offered to the parents who agreed and lasted 6 months, including the neurocognitive evaluation. The patients used Peak five times a day for 20 min. The Neuropsychological Attention and Memory Battery (NEUROPSI) was applied before and after the intervention. Results: The results revealed posttest changes in attention and executive function, memory, and total attention and memory. Significant clinical changes were observed, and the diagnostic range increased from severe to moderate. Conclusions: We concluded that, through an intervention with the Peak app, it is possible to enable attention and memory, which represent the main cognitive deficits in obese pediatric patients.

Sarcopenic obesity and brain health: A critical appraisal of the current evidence

Sarcopenic obesity (SO) is a body composition phenotype derived from the simultaneous presence in the same individual of an increase in fat mass and a decrease in skeletal muscle mass and/or function. Several protocols for the diagnosis of SO have been proposed in the last two decades making prevalence and disease risk estimates of SO heterogeneous and challenging to interpret. Dementia is a complex neurological disorder that significantly impacts patients, carers and healthcare systems. The identification of risk factors for early cognitive impairment and dementia is key to mitigating the forecasted trends of a 2-fold increase in dementia case numbers over the next two decades worldwide. Excess adiposity and sarcopenia have both been independently associated with risk of cognitive impairment and dementia. Whether SO is associated with a greater risk of cognitive impairment and dementia is currently uncertain. This review critically appraises the current evidence on the association between SO with cognitive outcomes and dementia risk. It also discusses some of the putative biological mechanisms that may link the SO phenotype with alteration of brain functions.

Associations of dynapenic abdominal obesity and its components with cognitive impairment among hemodialysis patients

OBJECTIVE

Cognitive impairment (CI) is a prevalent and significant health concern among patients undergoing maintenance hemodialysis (MHD). Recent studies have highlighted the growing interest in dynapenic abdominal obesity (DAO), which combines both low muscle strength and excess abdominal fat. Despite the increasing recognition of DAO, its association with CI in MHD patients remains uncertain. The objective of this study was to investigate the relationship between DAO and CI in MHD patients.

METHODS

We conducted a multicenter, cross-sectional study in twenty dialysis centers, encompassing 3767 adult MHD patients. Participants were categorized into four distinct groups based on the criteria for abdominal obesity (AO), defined as waist circumference (WC) ≥ 90 cm for men and ≥ 85 cm for women, and dynapenia, characterized by handgrip strength (HGS) < 28 kg in men and < 18 kg in women. The groups were: non-dynapenic/non-abdominal obesity (NDNAO), non-dynapenic/abdominal obesity (NDAO), dynapenic/non-abdominal obesity (DNAO), and dynapenic/abdominal obesity (DAO). Cognitive function was assessed using the Mini-Mental State Examination (MMSE), with a score below 27 indicating cognitive impairment (CI). Multivariate logistic models were used to investigate the correlations between DAO and its components with the risk of CI. Smooth curve fittings were used to identify the potential nonlinear relationship between WC and the MMSE scores. The piecewise regression model was used for fitting while the log-likelihood ratio test was used to determine whether a significant inflection point existed. Additionally, we conducted a series of subgroup analyses to test the robustness of our results.

RESULTS

The multi-variable adjusted odds ratios (ORs) of CI for DNAO and DAO were 2.10 (1.68-2.62, P < 0.001) and 1.81 (1.40-2.33, P < 0.001), respectively. These findings were consistently observed across subgroup analyses, indicating robustness in our results. AO was associated with increased risk of CI in the crude model (OR 1.22, 95%CI 1.05-1.41; P = 0.008), however, it became a protective factor after adjusting for potential confounders (OR 0.84, 95%CI 0.71-0.98; P = 0.03). We identified a significant nonlinear relationship between WC, HGS, and MMSE scores (P for non-linearity < 0.05). Notably, an inflection point at 23.29 kg for HGS was determined through threshold effect analysis. Below a WC threshold of 101 cm, MMSE scores demonstrated a positive correlation with WC (β = 0.03, 95% CI 0.01-0.04, P < 0.001). However, this relationship did not achieve statistical significance for WC values above 101 cm.

CONCLUSIONS

Both DAO and DNAO are associated with increased odds of CI in MHD patients, with dynapenia being the major factor contributing to the increased odds of CI, while AO appears to play a protective role against CI.

What Is the Impact of Obesity-Related Comorbidities on the Risk of Premature Aging in Patients with Severe Obesity?: A Cross-Sectional Study

Background and Objectives: The relationships between aging, chronic diseases, and obesity remain complex and poorly understood. This study aimed to investigate the impact of comorbidities on premature aging in individuals with severe obesity. Materials and Methods: This cross-sectional study included 99 bariatric patients with severe obesity (SG) and 30 healthy volunteers (HC). SG was further divided into subgroups based on comorbidity status. Various markers of biological aging, including interleukin-6 (IL-6), C-reactive protein (CRP), telomere length (TL), attention speed, executive functions, and metabolic age, were evaluated. Results: Both subgroups of patients with obesity presented elevated levels of IL-6 and CRP, shorter TLs, lower outcomes in executive functioning tests, and greater metabolic age than healthy subjects. However, no significant differences were observed between patients with obesity with and without comorbidities. This study highlighted the impact of BMI on increased inflammation and revealed that hypertension and inflammation are associated with cognitive decline. Conclusions: These findings suggest that obesity, regardless of comorbidities, contributes to premature aging. The presence of hypertension was linked to cognitive function decline, emphasizing the multifaceted implications of obesity for the aging process.

Trajectories of general and central obesity beyond middle age in relation to late-life cognitive decline and dementia

OBJECTIVE

The objective was to evaluate the longitudinal patterns of central and general obesity, identify their genetic and behavioral risk determinants, and investigate the association of distinct obesity trajectories beyond middle age with subsequent cognitive decline and the risk of developing dementia in late life.

METHODS

Using a nationally representative, longitudinal, community-based cohort, we examined trajectory patterns of obesity over a 14-year span beyond middle age employing latent mixture modeling. We then evaluated their relationship with subsequent cognitive decline through linear mixed models and with the risk of developing dementia using Cox models, adjusting for confounding variables.

RESULTS

Among the 4751 eligible participants (mean age, 58.7 [SD 8.1] years; 57% female), our analysis identified five distinct BMI trajectories and four WC trajectories spanning a 14-year period. In comparison with individuals in the low-stable BMI group, characterized by a consistent and healthy body weight (range, 22.8-22.9 kg/m2), those in the high-stable group, maintaining a stable obesity status (range, 34.3-35.4 kg/m2), exhibited an elevated risk of developing dementia (odds ratio [OR], 1.43; 95% CI: 1.02 to 2.00) and experienced a more accelerated cognitive decline over 6 years (difference in 6-year decline, -0.11 SD [95% CI: -0.18 to -0.03]). Similarly, when compared with participants in the low-stable WC group, indicating a stable and healthy WC (range, 76-79 cm), those in the high-increasing WC group, showing an increasing trend (range, 115-122 cm), demonstrated an increased risk of developing dementia (OR, 1.57, 95% CI: 1.01 to 2.49) and experienced a swifter cognitive decline (OR: -0.18 [95% CI: -0.28 to -0.07]).

CONCLUSIONS

General and central obesity trajectories beyond midlife with persistently high or increasing patterns were significantly associated with an increased risk of developing cognitive decline and dementia in late life. Longitudinal obesity patterns may assist in precise identification of older adults at risk of developing cognitive impairment for targeted intervention.

The mediating role of body surface area-adjusted basal metabolic rate: effects of low muscle mass and central obesity on cognitive impairment in Chinese patients with type 2 diabetes mellitus

Background

This study investigates the relationship between basal metabolic rate (BMR), body composition, obesity indices, and cognitive impairment (CI) in middle-aged and older type 2 diabetes mellitus (T2DM) patients, assessing their potential role in CI screening.

Methods

A cross-sectional study included 1243 T2DM patients over 45 years old. CI was assessed using the Montreal Cognitive Assessment. BMR and body composition indices were measured through bioelectrical impedance analysis. The associations and predictions related to CI were explored using multivariable-adjusted logistic regression, restricted cubic spline (RCS) models, and receiver operating characteristic (ROC) curve analyses. Mediation analysis explored the role of BMR adjusted by body surface area (BMR/BSA) in CI risk.

Results

Patients with CI showed significantly lower BMR, BMR adjusted for height squared (BMR/Height²), BMR/BSA, appendicular skeletal muscle mass (ASM), and fat-free mass (FFM), alongside higher waist circumference (WC) and percentage of body fat. Logistic regression showed that participants in the fourth quartile of BMR, BMR/Height2, and BMR/BSA had approximately a 54% reduced risk of CI (odds ratio range 0.457 to 0.463). RCS analysis indicated a linear decrease in CI risk with increasing BMR metrics. ROC analysis indicated high predictive efficacy for CI with combined indicators, particularly BMR and FFM (area under the curve 0.645). Mediation analysis suggested that BMR/BSA played a significant mediating role in WC, ASM and FFM on CI risk, with a mediation proportion ranging from 45.73% to 50.87%.

Conclusion

Low energy expenditure assessed by BMR/BSA is an independent risk factor for increased CI risk in middle-aged and elderly T2DM patients. Central obesity, low muscle mass, and low energy expenditure significantly elevate CI risk in this population.

Associations between nutritional status and abdominal adiposity with cognitive domains and depressive symptoms in older persons with multimorbidity: Understanding an understudied population

BACKGROUND

Malnutrition is a prevalent issue among older persons and has been linked to adverse outcomes. Limited information exists regarding its connection with cognition and depression in older persons burdened by chronic diseases, experiencing heightened nutritional and psychosocial vulnerability. In this study, we examined the association between nutritional status, cognitive performance, and depressive symptomatology, in a cohort of older persons with multimorbidity.

METHODS

This was a cross-sectional study of 114 pluripathological older persons. Nutritional status was assessed through Mini Nutritional Assessment (MNA), body mass index (BMI) and waist and calf circumferences. Cognition was assessed using Montreal Cognitive Assessment (MoCA) and depressive symptoms were measured with the 15-item Geriatric Depression Scale (GDS-15).

RESULTS

MNA score was positively correlated with the MoCA's visuospatial score (rho=0.262) and, participants with normal nutritional status according to MNA, performed better in orientation (p=0.037) and abstraction (p=0.013) domains. MNA was also associated with depressive symptoms, with odds 8.6 times higher in malnourished participants (AOR 8.6, 95% CI 2.6-28.8, p=0.000). Abdominal obesity, meanwhile, was associated with a decrease of 3.33 points in the overall MoCA score (β -3.33, 95% CI=-5.92; -0.73, p=0.013).

CONCLUSION

In older persons with multimorbidity, abdominal obesity and malnutrition were factors associated with lower global and domain-specific cognitive performance and increased depressive symptomatology.

Application of a new definition of sarcopenic obesity in middle-aged and older adults and association with cognitive function: Findings from the National Health and Nutrition Examination Survey 1999-2002

BACKGROUND & AIMS

The role of sarcopenic obesity (SO) in impaired cognitive function has been investigated in several observational studies, but results have been mixed. This study applied the proposed European Society for Clinical Nutrition and Metabolism (ESPEN)-European Association for the Study of Obesity (EASO) definition of SO to a representative population aged ≥50 years to identify the association between SO and cognitive function.

METHODS

Data from the National Health and Nutrition Examination Survey 1999-2002 waves were used. At the screening phase, body mass index or waist circumference were used to evaluate obesity; sarcopenia was identified using the SARC-F questionnaire. At the diagnostic phase I and II, sarcopenia was assessed using knee extensor isometric strength and appendicular lean mass, and fat mass percent was used to assess obesity. Cognitive function in older participants (60-85 years) was assessed using the Digit Symbol Substitution Test. A self-reported memory question was used in middle-aged individuals (50-59 years).

RESULTS

The sample included 2356 participants (men, 44.7%). The prevalence of SO was 32.3%, 21.2% and 15.0% at the screening, diagnosis I, and diagnosis II, respectively. Significant associations between SO and cognitive impairment were observed in individuals aged 60-85 at diagnosis I (OR: 2.3, 95%CI 1.4-3.8, P = 0.007) and diagnosis II (OR: 2.7, 95%CI 1.5-4.9, P = 0.004).

CONCLUSION

The new ESPEN-EASO definition of SO identified a high prevalence of SO cases. A significant association between SO and poor cognitive function in older individuals was observed.

Association of waist-to-hip ratio adjusted for body mass index with cognitive impairment in middle-aged and elderly patients with type 2 diabetes mellitus: a cross-sectional study

BACKGROUND

Numerous reports indicate that both obesity and type 2 diabetes mellitus (T2DM) are factors associated with cognitive impairment (CI). The objective was to assess the relationship between abdominal obesity as measured by waist-to-hip ratio adjusted for body mass index (WHRadjBMI) and CI in middle-aged and elderly patients with T2DM.

METHODS

A cross-sectional study was conducted, in which a total of 1154 patients with T2DM aged ≥ 40 years were included. WHRadjBMI was calculated based on anthropometric measurements and CI was assessed utilizing the Montreal Cognitive Assessment (MoCA). Participants were divided into CI group (n = 509) and normal cognition group (n = 645). Correlation analysis and binary logistic regression were used to explore the relationship between obesity-related indicators including WHRadjBMI, BMI as well as waist circumference (WC) and CI. Meanwhile, the predictive power of these indicators for CI was estimated by receiver operating characteristic (ROC) curves.

RESULTS

WHRadjBMI was positively correlated with MoCA scores, independent of sex. The Area Under the Curve (AUC) for WHRadjBMI, BMI and WC were 0.639, 0.521 and 0.533 respectively, and WHRadjBMI had the highest predictive power for CI. Whether or not covariates were adjusted, one-SD increase in WHRadjBMI was significantly related to an increased risk of CI with an adjusted OR of 1.451 (95% CI: 1.261-1.671). After multivariate adjustment, the risk of CI increased with rising WHRadjBMI quartiles (Q4 vs. Q1 OR: 2.980, 95%CI: 2.032-4.371, P for trend < 0.001).

CONCLUSIONS

Our study illustrated that higher WHRadjBMI is likely to be associated with an increased risk of CI among patients with T2DM. These findings support the detrimental effects of excess visceral fat accumulation on cognitive function in middle-aged and elderly T2DM patients.

Fecal microbiota transplantation ameliorates high-fat diet-induced memory impairment in mice

Gut dysbiosis is linked to metabolic and neurodegenerative diseases and comprises a plausible link between high-fat diet (HFD) and brain dysfunction. Here we show that gut microbiota modulation by either antibiotic treatment for 5 weeks or a brief 3-day fecal microbiota transplantation (FMT) regimen from low-fat (control) diet-fed mice decreased weight gain, adipose tissue hypertrophy, and glucose intolerance induced by HFD in C57BL/6 male mice. Notably, gut microbiota modulation by FMT completely reversed impaired recognition memory induced by HFD, whereas modulation by antibiotics had less pronounced effect. Improvement in recognition memory by FMT was accompanied by decreased HFD-induced astrogliosis in the hippocampal cornu ammonis region. Gut microbiome composition analysis indicated that HFD diminished microbiota diversity compared to control diet, whereas FMT partially restored the phyla diversity. Our findings reinforce the role of the gut microbiota on HFD-induced cognitive impairment and suggest that modulating the gut microbiota may be an effective strategy to prevent metabolic and cognitive dysfunction associated with unfavorable dietary patterns.

Association of obesity to reaction time and visual memory in schizophrenia

Background

Both overweight and cognitive deficits are common among people with schizophrenia (SZ) and schizoaffective disorder. The results in earlier studies have been inconsistent on whether overweight is associated with cognitive deficits in psychotic disorders.

Aims

Our aim in this study was to detect possible associations between obesity and cognitive deficits among study participants with SZ and schizoaffective disorder.

Methods

The study sample included 5382 participants with a clinical diagnosis of SZ or schizoaffective disorder selected from the Finnish SUPER study. Obesity was measured both with body-mass index and waist circumference. The cognitive performance was evaluated with two tests from the Cambridge automated neuropsychological test battery: Reaction time was evaluated with the 5-choice serial reaction time task. Visual memory was evaluated with the paired associative learning test. The final analysis included a total sample of 4498 participants applicable for the analysis of the reaction time and 3967 participants for the analysis of the visual memory.

Results

Obesity measured with body-mass index was associated with better performance in reaction time task among both female and male participants. Among male participants, overweight was associated with better performance in the visual memory test. The waist circumference was not associated with cognitive measures.

Conclusions

The results suggest that obesity in people with SZ or schizoaffective disorder might not be associated with cognitive deficits but instead with better cognitive performance. The results were opposite from earlier literature on the general population. More research is required to better understand whether the results might be partly caused by the differences in the etiology of obesity between the general population and people with SZ.

Association between geriatric nutritional risk index and cognitive function in older adults with/without chronic kidney disease

BACKGROUND

Cognitive impairment is highly prevalent among patients with chronic kidney disease, who face an increased risk of cognitive decline. The aim of this study was to investigate the relationship between the Geriatric Nutritional Risk Index (GNRI) and cognitive function in older individuals, both with and without chronic kidney disease (CKD).

METHODS

In this study, we analyzed data from 2728 participants in the 2011-2014 National Health and Nutrition Examination Survey (NHANES). Cognitive function was measured using the Consortium to Establish a Registry for the Alzheimer's Disease Word Learning subtest (CERAD W-L), the animal fluency test (AFT), the digit symbol substitution test (DSST), and the global cognitive z-score. The GNRI, representing whole-body nutritional status, was calculated based on serum albumin, body weight, and ideal body weight. We employed weighted multiple linear regression analyses and subgroup analyses to assess the independent association of GNRI with cognitive function in CKD and non-CKD populations. Smoothing techniques were used to fit curves, and interaction tests were used to assess the robustness and specificity of the findings.

RESULTS

Our analyses revealed a significant positive association between higher GNRI levels and cognitive function in the older US population (for global z-score: β = 0.01; 95% confidence interval [CI] = 0.00, 0.01). This association remained consistent across various subgroup analyses, including those for different gender groups, age groups, smoking statuses, diabetes statuses, hypertension statuses, individuals with a BMI below 25, individuals who consumed alcohol, and non-Hispanic white individuals. Smoothed curve-fitting analyses indicated that the GNRI was linearly related to cognitive function. No statistically significant interactions were detected among these variables.

CONCLUSION

Our findings emphasize the positive association between GNRI and cognitive health in individuals with or without CKD, especially when combined with other risk factors. Consequently, enhancing the nutritional status of the elderly may serve as a viable strategy to thwart the onset of cognitive decline.

Association Between Body Composition Patterns, Cardiovascular Disease, and Risk of Neurodegenerative Disease in the UK Biobank

BACKGROUND AND OBJECTIVES

Accumulating evidence connects diverse components of body composition (e.g., fat, muscle, and bone) to neurodegenerative disease risk, yet their interplay remains underexplored. This study examines the associations between patterns of body composition and the risk of neurodegenerative diseases, exploring the mediating role of cardiovascular diseases (CVDs).

METHODS

This retrospective analysis used data from the UK Biobank, a prospective community-based cohort study. We included participants free of neurodegenerative diseases and with requisite body composition measurements at recruitment, who were followed from 5 years after recruitment until April 1, 2023, to identify incident neurodegenerative diseases. We assessed the associations between different components and major patterns of body composition (identified by principal component analysis) with the risk of neurodegenerative diseases, using multivariable Cox models. Analyses were stratified by disease susceptibility, indexed by polygenetic risk scores for Alzheimer and Parkinson diseases, APOE genotype, and family history of neurodegenerative diseases. Furthermore, we performed mediation analysis to estimate the contribution of CVDs to these associations. In addition, in a subcohort of 40,790 participants, we examined the relationship between body composition patterns and brain aging biomarkers (i.e., brain atrophy and cerebral small vessel disease).

RESULTS

Among 412,691 participants (mean age 56.0 years, 55.1% female), 8,224 new cases of neurodegenerative diseases were identified over an average follow-up of 9.1 years. Patterns identified as "fat-to-lean mass," "muscle strength," "bone density," and "leg-dominant fat distribution" were associated with a lower rate of neurodegenerative diseases (hazard ratio [HR] = 0.74-0.94) while "central obesity" and "arm-dominant fat distribution" patterns were associated with a higher rate (HR = 1.13-1.18). Stratification analysis yielded comparable risk estimates across different susceptibility groups. Notably, 10.7%-35.3% of the observed associations were mediated by CVDs, particularly cerebrovascular diseases. The subcohort analysis of brain aging biomarkers corroborated the findings for "central obesity," "muscle strength," and "arm-dominant fat distribution" patterns.

DISCUSSION

Our analyses demonstrated robust associations of body composition patterns featured by "central obesity," "muscle strength," and "arm-dominant fat distribution" with both neurodegenerative diseases and brain aging, which were partially mediated by CVDs. These findings underscore the potential of improving body composition and early CVD management in mitigating risk of neurodegenerative diseases.

Association between weight-adjusted-waist index and cognitive decline in US elderly participants

Objective

To investigate the association between the weight-adjusted-waist index (WWI) and cognitive decline in elderly Americans from 2011 to 2014.

Methods

A cross-sectional study was conducted on 2,762 elderly participants from the National Health and Nutrition Examination (NHANES) between 2011 and 2014. WWI was calculated by dividing waist circumference (cm) by the square root of body weight (kg). Participants assessed their cognitive functions using tests such as the DSST, AFT, and CERAD W-L. In this research, multiple logistic regression, HIA, limited cubic spline (RCS), and threshold effect analysis methods were utilized to explore the relationship between cognitive decline and WWI.

Results

The study involved 2,762 participants aged 60 years and older, comprising 1,353 males (49%) and 1,409 females (51%), with a median age of 69.3 years (standard deviation = 6.7). The analysis revealed that the risk of cognitive decline was positively associated with the WWI. Fully adjusted models indicated significant correlations with the CERAD W-L [odds ratio (OR) = 1.24, 95% confidence interval (CI) = 1.06-1.46, p < 0.008], AFT (OR = 1.27, 95% CI = 1.08-1.49, p = 0.003), and DSST (OR = 1.56, 95% CI = 1.29-1.9, p < 0.001). Subgroup analysis demonstrated a consistent relationship across different population settings except for gender (average of interactions, p > 0.05). A J-shaped relationship between WWI and low DSST scores was observed using multivariate restricted cubic spline (RCS) regression (P for non-linearity <0.05), with the curve steepening when WWI ≥ 12.21 cm/√kg. Additionally, the study found that WWI was more strongly associated with an increased risk of cognitive decline than other obesity indicators such as Body Mass Index (BMI), waist circumference (WC), and A Body Shape Index (ABSI).

Conclusion

Our data have shown a significant positive association between the WWI and a higher risk of cognitive decline in older Americans, with a J-shaped non-linear relationship between WWI and DSST. In addition, our findings indicate that WWI was associated with greater cognitive decline than other markers of obesity.

The role of early cerebral edema and hematoma assessment in aneurysmal subarachnoid hemorrhage (a-SAH) in predicting early brain injury (EBI) and cognitive impairment: a case controlled study

BACKGROUND

Early assessment and management of cerebral edema and hematoma following aneurysmal subarachnoid hemorrhage (a-SAH) can significantly impact clinical cognitive outcomes. However, current clinical practices lack predictive models to identify early structural brain abnormalities affecting cognition. To address this gap, the authors propose the development of a predictive model termed the a-SAH Early Brain Edema/Hematoma Compression Neural (Structural Brain) Networks Score System (SEBE-HCNNSS).

METHODS

In this study, 202 consecutive patients with spontaneous a-SAH underwent initial computed tomography (CT) or MRI scans within 24 h of ictus with follow-up 2 months after discharge. Using logistic regression analysis (univariate and multivariate), the authors evaluated the association of clinically relevant factors and various traditional scale ratings with cognitive impairment (CI). Risk factors with the highest area under the curve (AUC) values were included in the multivariate analysis and least absolute shrinkage and selection operator (LASSO) analysis or Cox regression analysis.

RESULTS

A total of 177 patients were enrolled in the study, and 43 patients were classified with a high SEBE-HCNNSS grade (3-5). After a mean follow-up of 2 months, 121 individuals (68.36%) with a-SAH and three control subjects developed incident CI. The CT interobserver reliability of the SEBE-HCNNSS scale was high, with a Kappa value of 1. Furthermore, ROC analysis identified the SEBE-HCNNSS scale (OR 3.322, 95% CI: 2.312-7.237, P =0.00025) as an independent predictor of edema, CI, and unfavorable prognosis. These results were also replicated in a validation cohort.

CONCLUSION

Overall, the SEBE-HCNNSS scale represents a simple assessment tool with promising predictive value for CI and clinical outcomes post-a-SAH. Our findings indicate its practical utility as a prognostic instrument for risk evaluation after a-SAH, potentially facilitating early intervention and treatment.

White adipose tissue distribution and amount are associated with increased white matter connectivity

Obesity represents a significant public health concern and is linked to various comorbidities and cognitive impairments. Previous research indicates that elevated body mass index (BMI) is associated with structural changes in white matter (WM). However, a deeper characterization of body composition is required, especially considering the links between abdominal obesity and metabolic dysfunction. This study aims to enhance our understanding of the relationship between obesity and WM connectivity by directly assessing the amount and distribution of fat tissue. Whole-body magnetic resonance imaging (MRI) was employed to evaluate total adipose tissue (TAT), visceral adipose tissue (VAT), and subcutaneous adipose tissue (SAT), while MR liver spectroscopy measured liver fat content in 63 normal-weight, overweight, and obese males. WM connectivity was quantified using microstructure-informed tractography. Connectome-based predictive modeling was used to predict body composition metrics based on WM connectomes. Our analysis revealed a positive dependency between BMI, TAT, SAT, and WM connectivity in brain regions involved in reward processing and appetite regulation, such as the insula, nucleus accumbens, and orbitofrontal cortex. Increased connectivity was also observed in cognitive control and inhibition networks, including the middle frontal gyrus and anterior cingulate cortex. No significant associations were found between WM connectivity and VAT or liver fat. Our findings suggest that altered neural communication between these brain regions may affect cognitive processes, emotional regulation, and reward perception in individuals with obesity, potentially contributing to weight gain. While our study did not identify a link between WM connectivity and VAT or liver fat, further investigation of the role of various fat depots and metabolic factors in brain networks is required to advance obesity prevention and treatment approaches.

Associations of body habitus and its changes with incident dementia in older adults

BACKGROUND

This study examined the associations of body mass index (BMI) and waist circumference (WC), as well as their short- and long-term changes over time, with incident dementia in older individuals.

METHODS

Data came from 18,837 community-dwelling individuals aged 65+ years from Australia and the United States, who were relatively healthy without major cognitive impairment at enrolment. Anthropometric measures were prospectively assessed at baseline, as well as change and variability from baseline to year two (three time-points). In a subgroup (n = 11,176), self-reported weight at age 18 and 70+ years was investigated. Dementia cases satisfied DSM-IV criteria. Cox regression was used to examine the associations between anthropometric measures and incident risk of dementia.

RESULTS

Compared to normal weight, an overweight (HR: 0.67, 95%CI: 0.57-0.79, p < 0.001) or obese BMI (HR: 0.73, 95%CI: 0.60-0.89, p = 0.002), or a larger WC (elevated, HR: 0.71, 95%CI: 0.58-0.86, p < 0.001; highly elevated, HR: 0.65, 95%CI: 0.55-0.78, p < 0.001; relative to low) at baseline was associated with lower dementia risk. In contrast, substantial increases in BMI (>5%) over 2 years after baseline were associated with higher dementia risk (HR: 1.49, 95% CI: 1.17-1.91, p = 0.001). Increased dementia risk was also seen with an underweight BMI at baseline and a 2-year BMI decrease (>5%), but these associations appeared only in the first 4 years of follow-up. Compared to normal weight at both age 18 and 70+ years, being obese at both times was associated with increased dementia risk (HR: 2.27, 95%CI: 1.22-4.24, p = 0.01), while obesity only at age 70+ years was associated with decreased risk (HR: 0.70, 95%CI: 0.51-0.95, p = 0.02).

CONCLUSIONS

Our findings suggest that long-term obesity and weight gain in later life may be risk factors for dementia. Being underweight or having substantial weight loss in old age may be early markers of pre-clinical dementia.

Effects of a High-Fat Diet on Insulin-Related miRNAs in Plasma and Brain Tissue in APPSwe/PS1dE9 and Wild-Type C57BL/6J Mice

Insulin resistance (IR)-related miRNAs have been associated with the development and progression of Alzheimer's disease (AD). The dietary modulation of these miRNAs could become a potential strategy to manage AD. The aim of this study was to evaluate the effect of a high-fat diet (HFD), which aggravates AD-related pathogenic processes, on serum, cortex and hippocampus IR-related miRNA expression. C57BL/6J WT and APPSwe/PS1dE9 mice were fed either an HFD or a conventional diet till 6 months of age. The mice fed with the HFD showed a significant increase in body weight and worsening glucose and insulin metabolism. miR-19a-3p was found to be up-regulated in the cortex, hippocampus and serum of APP/PS1 mice and in the serum and hippocampus of WT mice fed with the HFD. miR-34a-5p and miR-146a-5p were up-regulated in the serum of both groups of mice after consuming the HFD. Serum miR-29c-3p was overexpressed after consuming the HFD, along with hippocampal miR-338-3p and miR-125b-5p, only in WT mice. The HFD modulated the expression of peripheral and brain miRNAs related to glucose and insulin metabolism, suggesting the potential role of these miRNAs not only as therapeutic targets of AD but also as peripheral biomarkers for monitoring AD.

Investigating the nexus of metabolic syndrome, serum uric acid, and dementia risk: a prospective cohort study

BACKGROUND

The global dementia prevalence is surging, necessitating research into contributing factors. We aimed to investigate the association between metabolic syndrome (MetS), its components, serum uric acid (SUA) levels, and dementia risk.

METHODS

Our prospective study comprised 466,788 participants without pre-existing MetS from the UK Biobank. We confirmed dementia diagnoses based on the ICD-10 criteria (F00-03). To evaluate the dementia risk concerning MetS, its components, and SUA levels, we applied Cox proportional hazards models, while adjusting for demographic factors.

RESULTS

Over a median follow-up of 12.7 years, we identified 6845 dementia cases. Individuals with MetS had a 25% higher risk of all-cause dementia (hazard ratio [HR] = 1.25, 95% confidence interval [CI] = 1.19-1.31). The risk increased with the number of MetS components including central obesity, dyslipidemia for high-density lipoprotein (HDL) cholesterol, hypertension, hyperglycemia, and dyslipidemia for triglycerides. Particularly for those with all five components (HR = 1.76, 95% CI = 1.51-2.04). Dyslipidemia for HDL cholesterol, hypertension, hyperglycemia, and dyslipidemia for triglycerides were independently associated with elevated dementia risk (p < 0.01). MetS was further linked to an increased risk of all-cause dementia (11%) and vascular dementia (VD, 50%) among individuals with SUA levels exceeding 400 μmol/L (all-cause dementia: HR = 1.11, 95% CI = 1.02-1.21; VD: HR = 1.50, 95% CI = 1.28-1.77).

CONCLUSIONS

Our study provides robust evidence supporting the association between MetS, its components, and dementia risk. These findings emphasize the importance of considering MetS and SUA levels in assessing dementia risk, offering valuable insights for prevention and management strategies.

Association between abdominal adiposity and cognitive decline in older adults: a 10-year community-based study

OBJECTIVES

This study aimed to investigate the association between abdominal adiposity and change in cognitive function in community-dwelling older adults.

DESIGN, SETTING, AND PARTICIPANTS

This longitudinal study included older adults aged ≥60 years without cognitive impairment who participated in the National Institute for Longevity Sciences - Longitudinal Study of Aging.

MEASUREMENTS

Cognitive function was evaluated biennially using the Mini-Mental State Examination (MMSE) over 10 years. Waist circumference (WC) was measured at the naval level, and subcutaneous fat area (SFA) and visceral fat area (VFA) were assessed using baseline computed tomography scans. WC, SFA, and VFA areas were stratified into sex-adjusted tertiles. A linear mixed model was applied separately for men and women.

RESULTS

This study included 873 older adults. In men, the groups with the highest levels of WC, SFA, and VFA exhibited a greater decline in MMSE score than the groups with the lowest levels (β [95% confidence interval]: WC, -0.12 [-0.23 to -0.01]; SFA, -0.13 [-0.24 to -0.02]; VFA, -0.11 [-0.22 to -0.01]). In women, the group with the highest level of WC and SFA showed a greater decline in MMSE score than the group with the lowest level (WC, -0.12 [-0.25 to -0.01]; SFA, -0.18 [-0.30 to -0.06]), but VFA was not associated with cognitive decline.

CONCLUSION

Higher WC, SFA, and VFA in men and higher WC and SFA in women were identified as risk factors for cognitive decline in later life, suggesting that abdominal adiposity involved in cognitive decline may differ according to sex.

Development and validation of a cognitive dysfunction risk prediction model for the abdominal obesity population

Objectives

This study was aimed to develop a nomogram that can accurately predict the likelihood of cognitive dysfunction in individuals with abdominal obesity by utilizing various predictor factors.

Methods

A total of 1490 cases of abdominal obesity were randomly selected from the National Health and Nutrition Examination Survey (NHANES) database for the years 2011-2014. The diagnostic criteria for abdominal obesity were as follows: waist size ≥ 102 cm for men and waist size ≥ 88 cm for women, and cognitive function was assessed by Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Word Learning subtest, Delayed Word Recall Test, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). The cases were divided into two sets: a training set consisting of 1043 cases (70%) and a validation set consisting of 447 cases (30%). To create the model nomogram, multifactor logistic regression models were constructed based on the selected predictors identified through LASSO regression analysis. The model's performance was assessed using several metrics, including the consistency index (C-index), the area under the receiver operating characteristic (ROC) curve (AUC), calibration curves, and decision curve analysis (DCA) to assess the clinical benefit of the model.

Results

The multivariate logistic regression analysis revealed that age, sex, education level, 24-hour total fat intake, red blood cell folate concentration, depression, and moderate work activity were significant predictors of cognitive dysfunction in individuals with abdominal obesity (p < 0.05). These predictors were incorporated into the nomogram. The C-indices for the training and validation sets were 0.814 (95% CI: 0.875-0.842) and 0.805 (95% CI: 0.758-0.851), respectively. The corresponding AUC values were 0.814 (95% CI: 0.875-0.842) and 0.795 (95% CI: 0.753-0.847). The calibration curves demonstrated a satisfactory level of agreement between the nomogram model and the observed data. The DCA indicated that early intervention for at-risk populations would provide a net benefit, as indicated by the line graph.

Conclusion

Age, sex, education level, 24-hour total fat intake, red blood cell folate concentration, depression, and moderate work activity were identified as predictive factors for cognitive dysfunction in individuals with abdominal obesity. In conclusion, the nomogram model developed in this study can effectively predict the clinical risk of cognitive dysfunction in individuals with abdominal obesity.

The joint effects of sarcopenia and cardiometabolic risk factors on declined cognitive function: Evidence from a 7-year cohort study

BACKGROUND

Sarcopenia and cardiometabolic risk factors are very common in the middle-aged and older population. This study aimed to explore the joint effect of sarcopenia and cardiometabolic risk factors on cognitive performance and cognitive decline.

METHODS

The definition of sarcopenia status was referenced in the AWGS 2019 algorithm. Linear regression models were used to explore the association of sarcopenia status with cognitive performance at baseline. Mixed effect models and multinomial logistic regression models were used to evaluate the long-term effect of sarcopenia status. The additive interaction between the effects of sarcopenia and cardiometabolic risk factors on cognitive performance was also evaluated.

RESULTS

In the cross-sectional analysis, sarcopenia and possible sarcopenia were associated with worse cognitive performance. In the longitudinal analysis, the participant with sarcopenia had a 0.34 [95 % CI (-0.43, -0.24)] lower global cognition score, and those with possible sarcopenia had a 0.20 [95 % CI (-0.27, -0.14)] lower global cognition score, compared with participants with no-sarcopenia. Sarcopenia and possible sarcopenia were identified as significant risk factors for cognitive decline. Sarcopenia combined with hypertension, type 2 diabetes, dyslipidemia, or abdominal obesity was associated with worse cognitive function.

LIMITATIONS

The assessment of cognitive function was not diagnosed accurately.

CONCLUSIONS

Sarcopenia and possible sarcopenia had adverse effects on cognitive performance and cognitive decline, sarcopenia combined with cardiometabolic risk factors can significantly enhance these effects. Therefore, the prevention of sarcopenia in the older population is crucial.

Midlife insulin resistance, APOE genotype, and change in late-life brain beta-amyloid accumulation - A 5-year follow-up [11C]PIB-PET study

We studied if midlife insulin resistance (IR) and APOE genotype would predict brain beta-amyloid (Aβ) accumulation and Aβ change in late-life in 5-year follow-up [11C]PIB-PET study. 43 dementia-free participants were scanned twice with [11C]PIB-PET in their late-life (mean age at follow-up 75.4 years). Participants were recruited from the Finnish Health2000 study according to their HOMA-IR values measured in midlife (mean age at midlife 55.4 years; IR+ group, HOMA-IR > 2.17; IR- group, HOMA-IR <1.25), and their APOEε4 genotype. At late-life follow-up, [11C]PIB-PET composite SUVr was significantly higher in IR+ group than IR- group (median 2.3 (interquartile range 1.7-3.3) vs. 1.7 (1.5-2.4), p = 0.03). There was no difference between IR- and IR+ groups in [11C]PIB-PET SUVr 5-year change, but the change was significantly higher in IR+/APOEε4+ group (median change 0.8 (0.60-1.0)) than in IR-/APOEε4- (0.28 (0.14-0.47), p = 0.02) and in IR+/APOEε4- group (0.24 (0.06-0.40), p = 0.046). These results suggest that APOEε4 carriers with midlife IR are at increased risk for late-life Aβ accumulation.

Gender-specific moderating role of abdominal obesity in the relationship between handgrip strength and cognitive impairment

BACKGROUND & AIMS

Both low handgrip strength (HGS) and abdominal obesity (AO) are associated with cognitive impairment. However, it remains unclear whether low HGS and AO interact to affect cognition, and whether the synergistic effect varies by gender. This study aimed to examine whether the association between low HGS and incident cognitive impairment was moderated by AO among Chinese older men and women.

METHODS

We used the data of participants (≥60 years) from four waves (2011-2018) of the China Health and Retirement Longitudinal Study. We defined low HGS as the maximal HGS of <28 kg in men and <18 kg in women, and AO as waist circumference of ≥90 cm for men and ≥80 cm for women. Cognitive impairment was defined as a global cognitive score in the lowest 10th percentile. For each gender, we used subdistribution hazards model to estimate subdistribution hazard ratios (SHRs) for the association of low HGS and AO with incident cognitive impairment, treating mortality as the competing event and controlling for other covariates. Multiplicative interaction was assessed through a cross-product interaction term of low HGS and AO in the model. Additive interaction between low HGS and AO was evaluated by calculating the relative excess risk due to interaction (RERI) and attributable proportion due to interaction (AP).

RESULTS

We included 3704 participants (Mean age: 66.9 ± 5.81; 54.9% male). During the 7-year follow-up, 1133 events of interest occurred (731 cognitive impairments and 402 deaths). Incidence rates of cognitive impairment and mortality were 4.1 (95% CI: 3.8 to 4.4) and 2.2 (95% CI: 2.0 to 2.5) per 100 person-years. There were positive multiplicative (SHR for the product term = 1.974, 95% CI: 1.114 to 3.500) and additive interactions (RERI = 1.056, 95% CI: 0.027 to 2.086, AP = 0.454, 95% CI: 0.158 to 0.750) of low HGS and AO on the risk of cognitive impairment among older men. Male participants with both low HGS and AO showed an increased risk of cognitive impairment (SHR = 2.325, 95% CI: 1.498 to 3.609) compared with those without either. There was no evidence of interaction among older women (SHR for the product term = 1.151, 95% CI: 0.725 to 1.825; RERI = 0.044, 95% CI: -0.524 to 0.613; AP = 0.039, 95% CI: -0.458 to 0.536).

CONCLUSIONS

Low HGS and AO may interact to synergistically increase the risk of cognitive impairment among Chinese older men. Screening the highest-risk subpopulation, who may benefit most from neurocognitive prevention strategies, may maximize potential public health gains.

The Presence and Severity of NAFLD are Associated With Cognitive Impairment and Hippocampal Damage

CONTEXT

Although cognitive impairment in nonalcoholic fatty liver disease (NAFLD) has received attention in recent years, little is known about detailed cognitive functions in histologically diagnosed individuals.

OBJECTIVE

This study aimed to investigate the association of liver pathological changes with cognitive features and further explore the underlying brain manifestations.

METHODS AND PATIENTS

We performed a cross-sectional study in 320 subjects who underwent liver biopsy. Among the enrolled participants, 225 underwent assessments of global cognition and cognitive subdomains. Furthermore, 70 individuals received functional magnetic resonance imaging scans for neuroimaging evaluations. The associations among liver histological features, brain alterations, and cognitive functions were evaluated using structural equation model.

RESULTS

Compared with controls, patients with NAFLD had poorer immediate memory and delayed memory. Severe liver steatosis (odds ratio, 2.189; 95% CI, 1.020-4.699) and ballooning (OR, 3.655; 95% CI, 1.419-9.414) were related to a higher proportion of memory impairment. Structural magnetic resonance imaging showed that patients with nonalcoholic steatohepatitis exhibited volume loss in left hippocampus and its subregions of subiculum and presubiculum. Task-based magnetic resonance imaging showed that patients with nonalcoholic steatohepatitis had decreased left hippocampal activation. Path analysis demonstrated that higher NAFLD activity scores were associated with lower subiculum volume and reduced hippocampal activation, and such hippocampal damage contributed to lower delayed memory scores.

CONCLUSIONS

We are the first to report the presence and severity of NAFLD to be associated with an increased risk of memory impairment and hippocampal structural and functional abnormalities. These findings stress the significance of early cognitive evaluation in patients with NAFLD.

The Role of Insulin-like Growth Factor I in Mechanisms of Resilience and Vulnerability to Sporadic Alzheimer's Disease

Despite decades of intense research, disease-modifying therapeutic approaches for Alzheimer's disease (AD) are still very much needed. Apart from the extensively analyzed tau and amyloid pathological cascades, two promising avenues of research that may eventually identify new druggable targets for AD are based on a better understanding of the mechanisms of resilience and vulnerability to this condition. We argue that insulin-like growth factor I (IGF-I) activity in the brain provides a common substrate for the mechanisms of resilience and vulnerability to AD. We postulate that preserved brain IGF-I activity contributes to resilience to AD pathology as this growth factor intervenes in all the major pathological cascades considered to be involved in AD, including metabolic impairment, altered proteostasis, and inflammation, to name the three that are considered to be the most important ones. Conversely, disturbed IGF-I activity is found in many AD risk factors, such as old age, type 2 diabetes, imbalanced diet, sedentary life, sociality, stroke, stress, and low education, whereas the Apolipoprotein (Apo) E4 genotype and traumatic brain injury may also be influenced by brain IGF-I activity. Accordingly, IGF-I activity should be taken into consideration when analyzing these processes, while its preservation will predictably help prevent the progress of AD pathology. Thus, we need to define IGF-I activity in all these conditions and develop a means to preserve it. However, defining brain IGF-I activity cannot be solely based on humoral or tissue levels of this neurotrophic factor, and new functionally based assessments need to be developed.

Elevated visceral adiposity index linked to improved cognitive function in middle-aged and elderly Chinese: evidence from the China health and retirement longitudinal study

Object

Cognitive decline and obesity are major global public health issues, and their association has been widely acknowledged. The link between the visceral adiposity index (VAI) and cognitive function in the Chinese population remains uncertain. This study aims to investigate the effects of VAI levels on cognitive function in the Chinese middle-aged and elderly population.

Methods

We analyzed longitudinal data from the China Health and Retirement Longitudinal Study (CHARLS) collected in 2011, 2013, 2015, and 2018. VAI levels were divided into three tertiles. Generalized estimating equation (GEE) models were used to explore the relationships between VAI levels and cognitive function, including overall cognitive scores, episodic memory, and mental status. Adjustments were made for potential confounders.

Results

The study consisted of 2,677 participants. Contrary to expectations, higher VAI levels were associated with higher overall cognitive scores and improved episodic memory scores, while no significant effect was observed on mental status. The GEE models consistently indicated that higher VAI levels were associated with higher overall cognitive scores, primarily due to their association with episodic memory. Stratified analyses revealed that the VAI was associated with better cognitive function primarily in males, individuals under 60 years old, those with lower education levels, rural residents, and married individuals, mainly in relation to episodic memory. No significant interactions were observed between VAI and demographic factors.

Conclusion

Our findings suggest that higher visceral adiposity is associated with slower cognitive decline in the Chinese middle-aged and elderly population, especially in its association with episodic memory. These results underline the need to further investigate the potential protective role of visceral fat in cognitive function, potentially offering new insights for interventions to enhance cognitive function and prevent dementia in this population.

Association between body mass index and cognitive impairment in Chinese older adults

Background

The association between body mass index (BMI) and the risk of cognitive impairment remains uncertain. Relatively few studies have analyzed the dose-response relationship between BMI and cognitive impairment. This article utilized nationally representative longitudinal data to assess the association between BMI and cognitive impairment in Chinese older adults.

Objective

The present study aimed to analyze the association between BMI and cognitive impairment in Chinese older people, including an investigation of gender differences and the dose-response relationship.

Methods

Data were obtained from the China Health and Retirement Longitudinal Study database in 2015 and 2018. The present study used logistic regression to analyze the relationship between baseline BMI and cognitive impairment, and adopted a restricted cubic spline model to plot dose-response curves for baseline BMI and prevalence of risk of cognitive impairment.

Results

The mean BMI of the survey population was 23.48 ± 3.66 kg/m2, and the detection rate of cognitive impairment was 34.2%. Compared to the normal weight group (18.5 ≤ BMI < 23.9 kg/m2), the odds ratio (OR) for cognitive impairment was 1.473 (95% CI: 1.189-1.823) in the underweight group (BMI < 18.5 kg/m2), whereas the corresponding OR was 0.874 (95% CI: 0.776-0.985) for the overweight or obese group (BMI ≥ 24.0 kg/m2) after adjusting for confounders. Gender subgroup analysis showed that overweight or obese older women were less likely to develop cognitive impairment (OR = 0.843; 95% CI: 0.720-0.987). The results of the restricted cubic spline analysis revealed a curvilinear L-shaped relationship between BMI and the risk of cognitive impairment (P non-linearity <0.05). In particular, the risk of cognitive impairment was higher at a lower baseline BMI. In contrast, BMI in the range of 23.2-27.8 kg/m2 was associated with a decreased risk of cognitive impairment.

Conclusion

BMI is a dose-dependent related factor for cognitive impairment in Chinese older adults. Being underweight is a risk factor for the development of cognitive impairment, while being overweight or obese is less likely to have cognitive impairment, particularly in female older people. Keeping BMI ranging from 23.2-27.8 kg/m2 in older adults can help maintain cognitive function.

Effects of Zinc Supplementation on Inflammatory and Cognitive Parameters in Middle-Aged Women with Overweight or Obesity

Obesity has been linked to cognitive decline and adverse effects on brain health. Zinc (Zn) is a mineral with important metabolic functions that can modulate obesity-related neurological impairment. Thus, the present study aimed to evaluate the effects of 12 weeks of Zn supplementation on the inflammatory profile, cognitive function, and mood of overweight or obese women through a double-blind, placebo-controlled study. The study included 42 women aged between 40 and 60, randomly divided into two groups: Zn supplementation (30 mg/day) or placebo for 12 weeks. Data regarding sociodemographic, anthropometric, dietary, and physical activity were collected. Mini-mental state examination (MMSE), verbal fluency test, clock drawing test, and Stroop test were performed. Anxiety and depression symptoms were assessed using the Beck anxiety inventory and the BDI-II, respectively. Saliva samples were collected to evaluate IL-1β, IL-6, TNF-α, insulin, nitrite, and Zn levels. Of the 42 participants (mean age 49.58 ± 6.46 years), 32 were included in the study analyses. Changes in body weight and macronutrient consumption were not different between placebo and Zn supplementation groups. Cognitive scores on the MMSE and Stroop tests were higher in the Zn supplementation group than in the placebo group. Salivary levels of IL-1b and Zn increased in the Zn group compared to placebo. There was no significant change in the adjusted means of the BDI-II and BECK scores between the zinc vs. placebo groups. Twelve weeks of Zn supplementation was able to partially improve the cognitive scores assessed in overweight or obese women, regardless of weight loss. These findings suggest that Zn supplementation can be considered an adjunct strategy to enhance cognitive health in overweight or obese women.

Mendelian randomization analyses identify bidirectional causal relationships of obesity with psychiatric disorders

BACKGROUND

Obesity have been showed to be strongly associated with psychiatric disorders, but the exact causality and the direction of the relationship remain inconclusive. Thus, we aimed to identify the causal associations between obesity and psychiatric disorders using two-sample Mendelian randomization (MR).

METHODS

Single-nucleotide polymorphisms associated with obesity, including body mass index (BMI), waist-hip ratio (WHR), and waist-hip ratio adjusted for BMI (WHRadjBMI), were extracted from a genome-wide association study of 694,649 European ancestry from the GIANT consortium. Summary level data for 10 psychiatric disorders were obtained from the Psychiatric Genomics Consortium. Inverse-variance weighted (IVW) method was used as the primary analysis, while several sensitivity analyses were applied to evaluate heterogeneity and pleiotropy.

RESULTS

The main MR results suggested higher BMI or WHR was positively causally associated with an increased risk of attention deficit hyperactivity disorder (ADHD), anorexia nervosa (AN), post-traumatic stress disorder (PTSD), major depressive disorder (MDD) and Alzheimer's disease (ALZ), but negatively causally associated with an increased risk of obsessive-compulsive disorder (OCD) and schizophrenia. For the reverse direction, ADHD and MDD were associated with an increased risk of obesity, but schizophrenia and ALZ were associated with a decreased risk of obesity.

CONCLUSION

Our findings support evidence of causal relationships between obesity and ADHD, MDD, PTSD, ALZ, SCZ, AN, and OCD, and confirmed the bidirectional causal relationships between obesity and ADHD, MDD, SCZ, and ALZ.

Mega-analysis of association between obesity and cortical morphology in bipolar disorders: ENIGMA study in 2832 participants

BACKGROUND

Obesity is highly prevalent and disabling, especially in individuals with severe mental illness including bipolar disorders (BD). The brain is a target organ for both obesity and BD. Yet, we do not understand how cortical brain alterations in BD and obesity interact.

METHODS

We obtained body mass index (BMI) and MRI-derived regional cortical thickness, surface area from 1231 BD and 1601 control individuals from 13 countries within the ENIGMA-BD Working Group. We jointly modeled the statistical effects of BD and BMI on brain structure using mixed effects and tested for interaction and mediation. We also investigated the impact of medications on the BMI-related associations.

RESULTS

BMI and BD additively impacted the structure of many of the same brain regions. Both BMI and BD were negatively associated with cortical thickness, but not surface area. In most regions the number of jointly used psychiatric medication classes remained associated with lower cortical thickness when controlling for BMI. In a single region, fusiform gyrus, about a third of the negative association between number of jointly used psychiatric medications and cortical thickness was mediated by association between the number of medications and higher BMI.

CONCLUSIONS

We confirmed consistent associations between higher BMI and lower cortical thickness, but not surface area, across the cerebral mantle, in regions which were also associated with BD. Higher BMI in people with BD indicated more pronounced brain alterations. BMI is important for understanding the neuroanatomical changes in BD and the effects of psychiatric medications on the brain.

Association of the Clínica Universidad de Navarra-Body Adiposity Estimator With Type 2 Diabetes: A Retrospective Cohort Study

Objectives: Clínica Universidad de Navarra-Body Adiposity Estimator (CUN-BAE) is considered to be a more accurate indicator of body fat estimation. We aimed to investigate the association of CUN-BAE with the risk of type 2 diabetes mellitus (T2DM) and to compare the strength of the association between CUN-BAE, body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR) and T2DM. Methods: The data were obtained from the annual health checkup database of residents in Xinzheng, China. From January 2011 to December 2021, 80,555 subjects aged ≥45 years met the inclusion criteria. Cox proportional hazard regression models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for CUN-BAE, BMI, WC, and WHtR in T2DM. Results: During a mean follow-up of 6.26 years, T2DM occurred in 12,967 subjects. The multivariable-adjusted HRs (95% CIs) of T2DM (highest vs. reference group) were 1.994 (1.811-2.196) for CUN-BAE, 1.751 (1.665-1.842) for WC, 1.715 (1.631-1.804) for WHtR, and 1.510 (1.436-1.588) for BMI, respectively. In addition, the risk of T2DM increased with baseline CUN-BAE (HR: 1.374; 95% CI: 1.328, 1.421), WC (HR: 1.236; 95% CI: 1.215, 1.256), WHtR (HR: 1.228; 95% CI: 1.208, 1.248), and BMI (HR: 1.175; 95% CI: 1.156, 1.195). Conclusion: Compared to BMI, WC or WHtR, CUN-BAE may more adequately reflect the adverse effects of adiposity on the risk of T2DM.

Leisure-Time Television Viewing and Computer Use, Family History, and Incidence of Dementia

INTRODUCTION

Time spent on screen-based sedentary activities is significantly associated with dementia risk, however, whether the associations vary by family history (FHx) of dementia is currently unknown. We aimed to examine independent associations of two prevalent types of screen-based sedentary activities (television [TV] viewing and computer use) with dementia and assess the modifying effect of FHx.

METHODS

We included 415,048 individuals free of dementia from the UK Biobank. Associations of TV viewing, computer use, and FHx with dementia risk were determined using Cox regression models. We estimated both multiplicative- and additive-scale interactions between TV viewing and computer use and FHx.

RESULTS

During a median follow-up of 12.6 years, 5,549 participants developed dementia. After adjusting for potential confounding factors, we observed that moderate (2-3 h/day; hazard ratio [HR] 1.13, 95% confidence interval 0.03-1.23) and high (>3 h/day; 1.33, 1.21-1.46) TV viewing was associated with a higher dementia risk, compared with low (0-1 h/day) TV viewing. Using restricted cubic spline models, the relationship of TV viewing with dementia was nonlinear (relative to 0 h/day; p for nonlinear = 0.005). We found that >3 h/day of TV viewing was associated with a 42% (1.42, 1.18-1.71) higher dementia risk in participants with FHx while a 30% (1.30, 1.17-1.45) in those without FHx. For computer use, both low (0 h/day; 1.41, 1.33-1.50) and high (>2 h/day; 1.17, 1.05-1.29) computer use were associated with elevated dementia risk, compared with moderate (1-2 h/day) computer use. We observed a J-shaped relationship with dementia (relative to 2 h/day; p for nonlinear <0.001). Compared with 1-2 h/day of computer use, the HRs of dementia were 1.46 (1.29-1.65) and 1.10 (0.90-1.36) for 0 h/day and >2 h/day of computer use in participants with FHx, respectively, while the corresponding HRs were 1.40 (1.30-1.50) and 1.19 (1.06-1.33) in those without FHx. We observed a positive additive interaction (RERI 0.29, 0.06-0.53) between computer use and FHx, while little evidence of interaction between TV viewing and FHx.

CONCLUSIONS

The time spent on TV viewing and computer use were independent risk factors for dementia, and the adverse effects of computer use and FHx were additive. Our findings point to new behavioral targets for intervention on preventing an early onset of dementia, especially for those with FHx.

Alzheimer's Disease: Causal Effect between Obesity and APOE Gene Polymorphisms

Currently studies on the correlation between obesity and Alzheimer's disease (AD) are still unclear. In addition, few indicators have been used to evaluate obesity, which has failed to comprehen-sively study the correlations between body fat mass, body fat distribution, and AD. Thus, this study innovatively utilized bioinformatics and Mendelian randomization (MR) to explore the key targets of obesity-induced AD, and investigate the causal associations between different types of obesity and key targets. The common targets of obesity and AD were screened using the GeneCards database, and functional and pathway annotations were carried out, thereby revealing the key target. MR analysis was conducted between body anthropometric indexes of obesity and the key target using an IVW model. Bioinformatics analysis revealed Apolipoprotein E (APOE) as the key target of obesity-induced AD. MR results showed that body mass index (BMI) had a negative causal association with APOE2, while body fat percentage (BFP) and trunk fat percentage (TFP) had no significant causal association with APOE2; BMI, BFP, and TFP had a negative causal association with APOE3, and none had any significant causal association with APOE4. In conclusion, there is a correlation between obesity and AD, which is mainly due to the polymorphism of the APOE gene rather than adipose tissue distribution. APOE3 carriers may be more susceptible to obesity, while the risk of AD caused by APOE2 and APOE4 may not be induced by obesity. This study sheds new light on current disputes. At the same time, it is suggested to regulate the body fat mass of APOE3 carriers in the early stage, and to reduce the risk of AD.

The Obesity Paradox: Effect of Body Mass Index and Waist Circumference on Post-Stroke Cognitive Impairment

Background

Obesity is a risk factor for dementia within the old population however not within the middle-aged population, that is referred to the "obesity paradox". This study explored the association of body mass index (BMI) and waist circumference (WC) with post-stroke cognitive impairment (PSCI) in middle-aged (40-65 years) versus old population (≥ 65 years).

Methods

The current study enrolled 1735 individuals over the age of 40 who had their first ischemic stroke from the Impairment of Cognition and Sleep (ICONS) subgroup of the China National Stroke Registry-3 (CNSR-3). BMI and WC were used for the diagnosis of obesity and central obesity, respectively. PSCI was diagnosed according to the Montreal Cognitive Assessment (MoCA). The main clinical outcome was the incidence of PSCI assessed at three months after stroke. Multivariable regression analysis was performed to evaluate the association between obesity and three-month PSCI. Stratified analysis was also performed to explore the effect of age on the relationship between obesity and PSCI.

Results

In the general population, multivariable logistic regression found that the adjusted odds ratio (OR) with 95% confidence interval (CI) of general obesity was 1.45 (1.06-1.98) and that of central obesity was 1.54 (1.24-1.91) for the three-month incidence of PSCI. Stratified analysis by age showed that the adjusted OR with a 95% CI of general obesity was 1.84 (1.24-2.72) in middle-aged patients and 0.89 (0.52-1.54) in elderly patients (p-value for interaction = 0.05). Central obesity was associated with PSCI in all age groups: 1.57 (1.18-2.09) in middle-aged patients and 1.52 (1.08-2.15) in elderly patients (p-value for interaction= 0.93).

Conclusion

General obesity was related to an increased risk of PSCI in middle-aged but not elderly patients, whereas central obesity was associated with an increased risk of PSCI in all age groups, suggesting that the obesity paradox arises only obesity is outlined by BMI.

Adipose tissue coregulates cognitive function

Obesity is associated with cognitive decline. Recent observations in mice propose an adipose tissue (AT)-brain axis. We identified 188 genes from RNA sequencing of AT in three cohorts that were associated with performance in different cognitive domains. These genes were mostly involved in synaptic function, phosphatidylinositol metabolism, the complement cascade, anti-inflammatory signaling, and vitamin metabolism. These findings were translated into the plasma metabolome. The circulating blood expression levels of most of these genes were also associated with several cognitive domains in a cohort of 816 participants. Targeted misexpression of candidate gene ortholog in the Drosophila fat body significantly altered flies memory and learning. Among them, down-regulation of the neurotransmitter release cycle-associated gene SLC18A2 improved cognitive abilities in Drosophila and in mice. Up-regulation of RIMS1 in Drosophila fat body enhanced cognitive abilities. Current results show previously unidentified connections between AT transcriptome and brain function in humans, providing unprecedented diagnostic/therapeutic targets in AT.