Sex-related differences in the prevalence of cognitive impairment among overweight and obese adults with type 2 diabetes

Predictors of Cognitive Impairment among Filipino Patients with Type 2 Diabetes Mellitus in a Tertiary Government Hospital

Background

Type 2 Diabetes Mellitus (T2DM) patients are predisposed to cognitive decline and dementia. The co-occurrence of the two diseases translate to a higher medical cost. Identification of factors contributing to cognitive impairment is warranted.

Objective

To determine the predictors of cognitive impairment among Filipino patients with Type 2 Diabetes Mellitus.

Methods

This is a cross-sectional analytical study involving Filipino patients diagnosed with T2DM in the outpatient clinic. A total of 171 patients were included and were screened using AD8-P tool.

Results

A total of 171 adult patients were included and screened for cognitive impairment.19.3% were cognitively impaired, with mean age of 59.6 years old (vs. 55.5 years old, p < 0.029), and two-thirds were female. The mean duration of the patient's diabetes was 11.2 years. After adjusting for confounders and multi-collinearity, the duration of diabetes was significantly associated with cognitive impairment with odds of developing cognitive impairment increasing as the duration reach 10 years above. Those with T2DM for at least ten years were 2.5 times more likely to develop cognitive impairment, holding the age constant. (OR = 2.5, 95% CI - 1.0 to 5.8, p < 0.043).

Conclusion

19.3% of Filipino patients with Type 2 Diabetes Mellitus in a tertiary government hospital are cognitively impaired and this can occur even in less than 65 years old. The ten years or longer duration of T2DM increases the risk of developing cognitive impairment by 2.5%.

Dysglycemia, gender, and cognitive performance in older persons living with mild cognitive impairment: findings from a cross-sectional, population-based study

OBJECTIVE

This study aims to examine the relationship between dysglycemia - also known as pre-diabetes or impaired glucose tolerance- and cognitive abilities in an older population living Mild Cognitive Impairment (MCI) and stratified by gender.

STUDY DESIGN

This is a retrospective study with data gathered from a large Italian clinical-based database.

MAIN OUTCOME MEASURES

The evaluation of cognitive performances by the Mini-Mental State Examination and the Addenbrooke's Cognitive Examination Revised rating scale as tests of screening and a comprehensive neuropsychological evaluation of several cognitive areas.

RESULTS

The study comprised 682 subjects (445 F/237 M) with a mean age of 76.08 ± 9.03 (range: 66-93) years. In all population, subjects with dysglycemia 193 (28.3%) had significantly poorer performance in memory (p = 0.006) and logic reasoning (p = 0.007) when compared with subjects without dysglycemia. The linear regression analyses revealed significant differences in the correlates of cognitive domains between gender groups. Independent of multiple covariates, women with dysglycemia showed worse performances in attention and short-term memory domains as compared with men. Even in the absence of dysglycemia women were more likely to show lower score in screening test of general cognition and attention.

CONCLUSIONS

Our findings suggest that dysglycemia in older individuals with MCI is associated with declines in specific cognitive domains, potentially influenced by gender. Implementing a comprehensive approach involving risk stratification and preventive strategies may be more effective in averting further cognitive decline in this high-risk population.

Diabetes mellitus and risk of incident dementia in APOE ɛ4 carriers: an updated meta-analysis

BACKGROUND AND AIM

Diabetes raises the risk of dementia, mortality, and cognitive decline in the elderly, potentially because of hereditary variables such as APOE. In this study, we aim to evaluate Diabetes mellitus and the risk of incident dementia in APOE ɛ4 carriers.

METHOD

We thoroughly searched PubMed (Medline), Scopus, and Google Scholar databases for related articles up to September 2023. The titles, abstracts, and full texts of articles were reviewed; data were extracted and analyzed.

RESULT

This meta-analysis included nine cohorts and seven cross-sectional articles with a total of 42,390 population. The study found that APOE ɛ4 carriers with type 2 diabetes (T2D) had a 48% higher risk of developing dementia compared to non-diabetic carriers (Hazard Ratio;1.48, 95%CI1.36-1.60). The frequency of dementia was 3 in 10 people (frequency: 0.3; 95%CI (0.15-0.48). No significant heterogeneity was observed. Egger's test, which we performed, revealed no indication of publication bias among the included articles (p = 0.2).

CONCLUSION

Overall, diabetes increases the risk of dementia, but further large-scale studies are still required to support the results of current research.

Prediction Model for Cognitive Impairment among Disabled Older Adults: A Development and Validation Study

Disabled older adults exhibited a higher risk for cognitive impairment. Early identification is crucial in alleviating the disease burden. This study aims to develop and validate a prediction model for identifying cognitive impairment among disabled older adults. A total of 2138, 501, and 746 participants were included in the development set and two external validation sets. Logistic regression, support vector machine, random forest, and XGBoost were introduced to develop the prediction model. A nomogram was further established to demonstrate the prediction model directly and vividly. Logistic regression exhibited better predictive performance on the test set with an area under the curve of 0.875. It maintained a high level of precision (0.808), specification (0.788), sensitivity (0.770), and F1-score (0.788) compared with the machine learning models. We further simplified and established a nomogram based on the logistic regression, comprising five variables: age, daily living activities, instrumental activity of daily living, hearing impairment, and visual impairment. The areas under the curve of the nomogram were 0.871, 0.825, and 0.863 in the internal and two external validation sets, respectively. This nomogram effectively identifies the risk of cognitive impairment in disabled older adults.

The impact of diabetes in cognitive impairment: A review of current evidence and prospects for future investigations

Cognitive impairment in individuals with diabetes represents a multifaceted and increasingly prevalent health concern. This review critically examines the current evidence regarding the intricate relationship between diabetes and cognitive decline. It highlights the existing knowledge on the impact of diabetes on cognitive function, spanning from mild cognitive impairment to dementia, including vascular and Alzheimer dementia. The review underscores the need for a standardized diagnostic paradigm and explores research gaps, such as the implications of cognitive impairment in younger populations and various diabetes types. Furthermore, this review emphasizes the relevance of diabetes-related comorbidities, including hypertension and dyslipidemia, in influencing cognitive decline. It advocates for a comprehensive, interdisciplinary approach, integrating insights from neuroscience, endocrinology, and immunology to elucidate the mechanistic underpinnings of diabetes-related cognitive impairment. The second part of this review outlines prospective research directions and opportunities. It advocates for longitudinal studies to understand disease progression better and identifies critical windows of vulnerability. The search for accurate biomarkers and predictive factors is paramount, encompassing genetic and epigenetic considerations. Personalized approaches and tailored interventions are essential in addressing the substantial variability in cognitive outcomes among individuals with diabetes.

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.

Physical activity in a swimming pool attenuates memory impairment by reducing glutamate and inflammatory cytokines and increasing BDNF in the brain of mice with type 2 diabetes

Type 2 diabetes is a risk factor for the development of cognitive impairment. Increasing evidence suggests that regular exercise is beneficial for the treatment of clinical symptoms in diabetic patients. The current study aimed to evaluate whether increasing physical activity through swimming training can reduce memory impairment in an animal model of type 2 diabetes. Diabetes and non-diabetes mice underwent swimming training for four weeks, and then working, spatial, and recognition memory were evaluated using three behavioral tests. Body weight, glucose, and insulin resistance were monitored. We also measured inflammatory cytokines (interleukin (IL)- 6, IL-1β, and tumor-necrosis-factor (TNF)-α), an anti-inflammatory cytokine (IL-10), and brain-derived-neurotrophic-factor (BDNF), and glutamate levels in the hippocampus or prefrontal cortex of mice. The findings showed that diabetes increased body weight, glucose, and insulin resistance, impaired working, spatial and recognition memory, increased levels of IL-6, IL-1β, TNF-α, and glutamate levels, and decreased BDNF in the hippocampus of diabetic mice. While higher physical activity was associated with reduced body weight, glucose, and insulin resistance, attenuated memory impairment, IL-6, IL-1β, TNF-α, and glutamate, and increased BDNF levels in the hippocampus and prefrontal cortex of diabetic mice. This study shows that swimming training can normalize body weight and glucose-insulin axis and reduce inflammation and glutamate in the hippocampus and enhance the neurotrophic system in both the hippocampus and prefrontal cortex of diabetic mice. This study also suggests that higher physical activity through swimming training can improve cognitive impairment in a mouse model of type 2 diabetes.

Daytime Sleepiness Is Associated with Lower Cognitive Scores: The Look AHEAD Study

Background

Daytime sleepiness is common in older adults and may result from poor nighttime sleep due to sleep disordered breathing, fragmented sleep, or other sleep disorders. Daytime sleepiness may be associated with cognition in older adults.

Objectives

We investigated the association between self-reported daytime sleepiness and cognitive function in the Look AHEAD clinical trial.

Design

Observational follow-up of a randomized clinical trial of an intensive lifestyle intervention.

Setting

Clinic.

Participants

Participants (n=1,778) aged 45-76 years at baseline with type 2 diabetes and overweight or obesity.

Interventions

Participants were randomized to an intensive lifestyle intervention for weight loss or a control condition of diabetes support and education.

Measurements

Participants provided self-reported levels of daytime sleepiness at baseline and years 12-13. Cognitive function was assessed with a neurocognitive battery at years 12-13 and 18-20.

Results

Participants who reported having frequent daytime sleepiness (often or always) performed significantly worse than others on the cognitive composite (-0.35; p-value=0.014) after controlling for covariates. When stratified by intervention arm, participants assigned to the intensive lifestyle intervention who reported often/always having daytime sleepiness performed worse on Digit Symbol Coding (-0.63; p-value=0.05) and Trail Making Part-B (-0.56; p-value=0.02) after controlling for covariates. Statistical interactions revealed associations between daytime sleepiness and the following covariates: race and ethnicity, APOE ε4 carrier status, baseline history of cardiovascular disease, and depression.

Conclusions

Daytime sleepiness over ~13 years predicted poorer cognitive performance in older individuals who, by virtue of having diabetes and overweight/obesity, are at high risk for sleep disorders and cognitive impairment.

The aging brain: risk factors and interventions for long term brain health in women

PURPOSE OF REVIEW

Poor cognitive aging and dementia pose a significant public health burden, and women face unique risks compared to men. Recent research highlights the role of genetics, menopause, chronic disease, and lifestyle in risk and resilience in women's cognitive aging. This work suggests avenues for clinical action at midlife that may change the course of brain health in aging.

RECENT FINDINGS

Studies indicate women's risk for poor cognitive aging relates in part to hormone changes at menopause, a time when memory, brain structure and function, and Alzheimer's pathology may be observed in women and not men. Medical and lifestyle risks including diabetes, hypertension, and low physical activity also contribute to women's unique risks. At the same time, literature on resilience suggests women may benefit from lifestyle and chronic disease intervention, possibly more than men. Current studies emphasize the importance of interacting genetic and lifestyle risks, and effects of social determinants of health.

SUMMARY

Women have greater risk than men for poor cognitive aging; however, by treating the whole person, including genetics, lifestyle, and social environment, clinicians have an opportunity to support healthy cognitive aging in women and reduce the future public health burden of dementia.

Sex and gender considerations in Alzheimer’s disease: The Women’s Brain Project contribution

The global population is expected to have about 131.5 million people living with Alzheimer’s disease (AD) and other dementias by 2050, posing a severe health crisis. Dementia is a progressive neurodegenerative condition that gradually impairs physical and cognitive functions. Dementia has a variety of causes, symptoms, and heterogeneity concerning the influence of sex on prevalence, risk factors, and outcomes. The proportion of male-to-female prevalence varies based on the type of dementia. Despite some types of dementia being more common in men, women have a greater lifetime risk of developing dementia. AD is the most common form of dementia in which approximately two-thirds of the affected persons are women. Profound sex and gender differences in physiology and pharmacokinetic and pharmacodynamic interactions have increasingly been identified. As a result, new approaches to dementia diagnosis, care, and patient journeys should be considered. In the heart of a rapidly aging worldwide population, the Women’s Brain Project (WBP) was born from the necessity to address the sex and gender gap in AD. WBP is now a well-established international non-profit organization with a global multidisciplinary team of experts studying sex and gender determinants in the brain and mental health. WBP works with different stakeholders worldwide to help change perceptions and reduce sex biases in clinical and preclinical research and policy frameworks. With its strong female leadership, WBP is an example of the importance of female professionals’ work in the field of dementia research. WBP-led peer-reviewed papers, articles, books, lectures, and various initiatives in the policy and advocacy space have profoundly impacted the community and driven global discussion. WBP is now in the initial phases of establishing the world’s first Sex and Gender Precision Medicine Institute. This review highlights the contributions of the WBP team to the field of AD. This review aims to increase awareness of potentially important aspects of basic science, clinical outcomes, digital health, policy framework and provide the research community with potential challenges and research suggestions to leverage sex and gender differences. Finally, at the end of the review, we briefly touch upon our progress and contribution toward sex and gender inclusion beyond Alzheimer’s disease.

Long-term high-fat diet increases glymphatic activity in the hypothalamus in mice

Obesity affects millions of people worldwide and is associated with an increased risk of cognitive decline. The glymphatic system is a brain-wide metabolic waste clearance system, dysfunction of which is linked to dementia. We herein examined glymphatic transport in mice with long-term obesity induced by a high-fat diet for 10 months. The obese mice developed hypertension and elevated heart rate, neuroinflammation and gliosis, but not apparent systemic inflammation. Surprisingly, glymphatic inflow was globally unaffected by the high-fat diet except for the hypothalamus, which displayed increased influx and elevated AQP4 vascular polarization compared to the normal weight control group. We propose that a long-term high-fat diet induced metabolic alteration of hypothalamic neurons and neuroinflammation, which in turn enhanced glymphatic clearance in the effected brain region.

Fingolimod Alleviates Cognitive Deficit in Type 2 Diabetes by Promoting Microglial M2 Polarization via the pSTAT3-jmjd3 Axis

Sphingosine receptors (S1PRs) are implicated in the progression of neurodegenerative diseases and metabolic disorders like obesity and type 2 diabetes (T2D). The link between S1PRs and cognition in type 2 diabetes, as well as the mechanisms that underpin it, are yet unknown. Neuroinflammation is the common pathology shared among T2D and cognitive impairment. However, the interplay between the M1 and M2 polarization state of microglia, a primary driver of neuroinflammation, could be the driving factor for impaired learning and memory in diabetes. In the present study, we investigated the effects of fingolimod (S1PR1 modulator) on cognition in high-fat diet and streptozotocin-induced diabetic mice. We further assessed the potential pathways linking microglial polarization and cognition in T2D. Fingolimod (0.5 mg/kg and 1 mg/kg) improved M2 polarization and synaptic plasticity while ameliorating cognitive decline and neuroinflammation. Sphingolipid dysregulation was mimicked in vitro using palmitate in BV2 cells, followed by conditioned media exposure to Neuro2A cells. Mechanistically, type 2 diabetes induced microglial activation, priming microglia towards the M1 phenotype. In the hippocampus and cortex of type 2 diabetic mice, there was a substantial drop in pSTAT3, which was reversed by fingolimod. This protective effect of fingolimod on microglial M2 polarization was primarily suppressed by selective jmjd3 blockade in vitro using GSK-J4, revealing that jmjd3 was involved downstream of STAT3 in the fingolimod-enabled shift of microglia from M1 to M2 polarization state. This study suggested that fingolimod might effectively improve cognition in type 2 diabetes by promoting M2 polarization.

Cognition and Diabetes: Examining Sex Differences Using a Longitudinal Sample of Older Adults

Objectives: This study aims to investigate sex-based differences in the diabetes status and cognition relationship using a representative sample of older Americans. Methods: Using a sample of 19,190 females and 15,580 males from the Health and Retirement Study, we conduct mixed-effects linear regression analyses to examine sex differences in the association between diabetes and cognition over a 20-year follow-up period among older adults in the United States. Main Findings: Females experience slightly steeper declines in cognition that are further exacerbated by diabetes. At age 65, females without diabetes have significantly higher cognition than males; this gap is eliminated by age 85. Among diabetics, there is no initial sex disparity, but females' cognition becomes significantly lower than males' over the following 20 years. Principal Conclusions: Relative to males, females are particularly susceptible to diabetes-related declines in cognition with increasing age.

Associations between cognitive function and endogenous levels of estradiol and testosterone in adults with type 2 diabetes

AIMS

To assess associations that endogenous estradiol and testosterone levels have with cognitive function in older adults with Type 2 diabetes mellitus (T2DM).

METHODS

We use data from the Look AHEAD clinical trial of behavioral weight loss. Endogenous estradiol and total testosterone levels were determined using stored serum from 996 individuals, mean age 69 years, at two times (averaging 4 years apart) during years 8-18 of follow-up. One to four standardized assessments of attention, executive function, memory, and verbal fluency were collected during this follow-up. Mixed effects models and multiple imputation were used to assess associations that estradiol and total testosterone levels had with body mass index and cognitive function.

RESULTS

Estradiol levels were not associated with cognitive function in either sex. Total testosterone levels were not associated with cognitive function in women, but greater total testosterone levels were associated with better verbal fluency in men (p < 0.001), most strongly among those carrying the APOE-e4 allele (interaction p = 0.02). The weight loss intervention left a legacy of relatively lower cognitive functioning among women, which was not mediated by current levels of sex hormones.

CONCLUSIONS

Behavioral weight loss intervention does not affect cognitive functioning through mechanisms related to estradiol or testosterone.

CLINICALTRIALS

gov Identifier: NCT00017953.

Targeted Mitochondrial Epigenetics: A New Direction in Alzheimer’s Disease Treatment

Mitochondrial epigenetic alterations are closely related to Alzheimer’s disease (AD), which is described in this review. Reports of the alteration of mitochondrial DNA (mtDNA) methylation in AD demonstrate that the disruption of the dynamic balance of mtDNA methylation and demethylation leads to damage to the mitochondrial electron transport chain and the obstruction of mitochondrial biogenesis, which is the most studied mitochondrial epigenetic change. Mitochondrial noncoding RNA modifications and the post-translational modification of mitochondrial nucleoproteins have been observed in neurodegenerative diseases and related diseases that increase the risk of AD. Although there are still relatively few mitochondrial noncoding RNA modifications and mitochondrial nuclear protein post-translational modifications reported in AD, we have reason to believe that these mitochondrial epigenetic modifications also play an important role in the AD process. This review provides a new research direction for the AD mechanism, starting from mitochondrial epigenetics. Further, this review summarizes therapeutic approaches to targeted mitochondrial epigenetics, which is the first systematic summary of therapeutic approaches in the field, including folic acid supplementation, mitochondrial-targeting antioxidants, and targeted ubiquitin-specific proteases, providing a reference for therapeutic targets for AD.

Type 2 diabetes mellitus-associated cognitive dysfunction: Advances in potential mechanisms and therapies

Type 2 diabetes (T2D) and its target organ injuries cause distressing impacts on personal health and put an enormous burden on the healthcare system, and increasing attention has been paid to T2D-associated cognitive dysfunction (TDACD). TDACD is characterized by cognitive dysfunction, delayed executive ability, and impeded information-processing speed. Brain imaging data suggest that extensive brain regions are affected in patients with T2D. Based on current findings, a wide spectrum of non-specific neurodegenerative mechanisms that partially overlap with the mechanisms of neurodegenerative diseases is hypothesized to be associated with TDACD. However, it remains unclear whether TDACD is a consequence of T2D or a complication that co-occurs with T2D. Theoretically, anti-diabetes methods are promising neuromodulatory approaches to reduce brain injury in patients with T2D. In this review, we summarize potential mechanisms underlying TDACD and promising neurotropic effects of anti-diabetes methods and some neuroprotective natural compounds. Constructing screening or diagnostic tools and developing targeted treatment and preventive strategies would be expected to reduce the burden of TDACD.

Comparing data-driven and hypothesis-driven MRI-based predictors of cognitive impairment in individuals from the Atherosclerosis Risk in Communities (ARIC) study

INTRODUCTION

A data-driven index of dementia risk based on magnetic resonance imaging (MRI), the Alzheimer's Disease Pattern Similarity (AD-PS) score, was estimated for participants in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS

AD-PS scores were generated for 839 cognitively non-impaired individuals with a mean follow-up of 4.86 years. The scores and a hypothesis-driven volumetric measure based on several brain regions susceptible to AD were compared as predictors of incident cognitive impairment in different settings.

RESULTS

Logistic regression analyses suggest the data-driven AD-PS scores to be more predictive of incident cognitive impairment than its counterpart. Both biomarkers were more predictive of incident cognitive impairment in participants who were White, female, and apolipoprotein E gene (APOE) ε4 carriers. Random forest analyses including predictors from different domains ranked the AD-PS scores as the most relevant MRI predictor of cognitive impairment.

CONCLUSIONS

Overall, the AD-PS scores were the stronger MRI-derived predictors of incident cognitive impairment in cognitively non-impaired individuals.

Legacy of a 10-Year Multidomain Lifestyle Intervention on the Cognitive Trajectories of Individuals with Overweight/Obesity and Type 2 Diabetes Mellitus

INTRODUCTION

Weight loss and increased physical activity interventions are commonly recommended for individuals with type 2 diabetes (T2D) and overweight or obesity. We examined the impact of randomization to an intensive lifestyle intervention (ILI) on trajectories of cognitive function over 10 years in a cohort of participants in a randomized clinical trial who had T2D and overweight/obesity at baseline.

METHODS

Participants aged 45-76 years were enrolled in 2001-2004 and were randomized to the ILI or a diabetes support and education (DSE) condition. Cognitive function was assessed in 3,938 participants at up to 4 time points 8-18 years after randomization. General linear mixed effects models examined cognitive trajectories over time. Subgroup analyses focused on sex, individuals with baseline body mass index >30, those carrying the APOE ε4 allele, and those with a baseline history of cardiovascular disease (CVD).

RESULTS

Overall, there were no differences in the rate of cognitive decline by intervention arm. Subgroup analyses showed that participants who had a baseline history of CVD and were randomized to the ILI arm of the study performed significantly worse on the Stroop Color Word Test than those in the DSE arm.

DISCUSSION/CONCLUSIONS

The ILI did not result in preserved cognitive function or slower rates of cognitive decline in this cohort of individuals who had T2D and were overweight or obese at baseline.

Sex-related differences in cognitive trajectories in older individuals with type 2 diabetes and overweight or obesity

INTRODUCTION

It is unknown whether rates of cognitive decline differ between older women and men with type 2 diabetes (T2D) and overweight or obesity.

METHODS

Two to four cognitive assessments were obtained across up to 10 years from 2799 adults (mean age 68 years; 62% women) with T2D who had been enrolled in a clinical trial of weight loss intervention. Sex-related differences in means and rates of decline of cognitive scores were assessed.

RESULTS

Women outperformed men in verbal learning and processing speed (P < 0.001), but not executive function (P = 0.22). The rates of decline over time for women and men were similar (P ≥  0.10); however women, but not men, with apolipoprotein E (APOE) ε4 alleles had steeper declines in verbal learning (P = 0.02) and processing speed (P = 0.007) than those without these alleles.

DISCUSSION

Cognitive advantages for women with T2D and overweight/obesity over men are preserved as they age; however, these are eroded by the APOE ε4 genotype.

Melatonin prevents diabetes-associated cognitive dysfunction from microglia-mediated neuroinflammation by activating autophagy via TLR4/Akt/mTOR pathway

Cognitive dysfunction often occurs in diabetes mellitus patients. This study aimed to investigate the efficacy of melatonin (MLT) in improving diabetes-associated cognitive decline and the underlying mechanism involved. Type 2 diabetic mice and palmitic acid (PA)-stimulated BV-2 cells were treated by MLT, and the potential mechanisms among MLT, cognition, and autophagy were explored. The results showed that type 2 diabetic mice showed obvious learning and memory impairments in the Morris water maze test compared with normal controls, which could be ameliorated by MLT treatment. Meanwhile, MLT administration significantly improved neuroinflammation and regulated microglial apoptosis. Furthermore, autophagy inhibitor 3-methyladenine (3-MA) increased the microglial inflammation and apoptosis, indicating that the treatment effect of MLT was mediated by autophagy. Lastly, MLT treatment significantly decreased the levels of toll-like receptors 4 (TLR4), phosphorylated-protein kinase B (Akt), and phosphorylated-mechanistic target of rapamycin (mTOR), indicating that blocking TLR4/Akt/mTOR pathway might be an underlying basis for the anti-inflammatory and anti-apoptosis effects of MLT. Collectively, our study suggested that MLT could improve learning and memory in type 2 diabetic mice by activating autophagy via the TLR4/Akt/mTOR pathway, thereby inhibiting neuroinflammation and microglial apoptosis.

Sex, diabetes status and cognition: findings from the study of longevity in diabetes

INTRODUCTION

Women comprise two-thirds of people with dementia, making female sex a significant dementia risk factor. Both type 1 diabetes (T1D) and type 2 diabetes (T2D) are known dementia risk factors with an increasing global incidence. Understanding whether subtle sex differences persist in cognitive function prior to dementia in the context of diabetes may help elucidate the magnitude of sex effects on dementia risk.

RESEARCH DESIGN AND METHODS

We examined cross-sectional data from the Study of Longevity in Diabetes (SOLID), a prospective cohort study of members of Kaiser Permanente Northern California aged 60 years and older with T1D (n=758), T2D (n=232) and without either T1D or T2D (n=247). We used factor analysis to generate summary scores of cognitive domains and used regression analyses to examine the associations between sex and cognition adjusting for sociodemographic and cardiovascular confounders.

RESULTS

We included 1237 participants (630 women and 607 men) with mean age 68 years. By design, the distribution of men and women in T1D, T2D and no diabetes was similar. Women had better cognitive performance than men in global cognition (β=0.21, 95% CI 0.16 to 0.26), language (β=0.08, 95% CI 0.004 to 0.15), executive function (β=0.13, 95% CI 0.05 to 0.20), episodic verbal memory (β=0.68, 95% CI 0.59 to 0.77) and attention (β=0.20, 95% CI 0.11 to 0.28) but not in episodic visual memory (β=0.006, 95% CI -0.07 to 0.09) adjusting for age and education independent of diabetes status. We did not find an interaction between sex and diabetes status for any of the cognitive outcomes.

CONCLUSIONS

Women in late mid-life have better cognitive performance than men in many cognitive domains independent of the presence of T1D or T2D. Further work is required to understand whether these differences change over time or in older cohorts and to understand their relationship to subsequent dementia.

Cognitive Function, Access to Kidney Transplantation, and Waitlist Mortality Among Kidney Transplant Candidates With or Without Diabetes

RATIONALE & OBJECTIVE

Intact cognition is generally a prerequisite for navigating through and completing evaluation for kidney transplantation. Despite kidney transplantation being contraindicated for those with severe dementia, screening for more mild forms of cognitive impairment before referral is rare. Candidates may have unrecognized cognitive impairment, which may prolong evaluation, elevate mortality risk, and hinder access to kidney transplantation. We estimated the burden of cognitive impairment and its association with access to kidney transplantation and waitlist mortality.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

3,630 participants (January 2009 to June 2018) with cognitive function measured (by the Modified Mini-Mental State Examination [3MS]) at kidney transplantation evaluation at 1 of 2 transplantation centers.

PREDICTORS

Cognitive impairment (3MS score<80).

OUTCOMES

Listing, waitlist mortality, and kidney transplantation.

ANALYTICAL APPROACH

We estimated the adjusted chance of listing (Cox regression), risk for waitlist mortality (competing-risks regression), and kidney transplantation rate (Poisson regression) by cognitive impairment. Given potential differences in cause of cognitive impairment among those with and without diabetes, we tested whether these associations differed by diabetes status using a Wald test.

RESULTS

At evaluation, 6.4% of participants had cognitive impairment, which was independently associated with 25% lower chance of listing (adjusted HR, 0.75; 95% CI, 0.61-0.91); this association did not differ by diabetes status (Pinteraction=0.07). There was a nominal difference by diabetes status for the association between cognitive impairment and kidney transplantation rate (Pinteraction=0.05), while the association between cognitive impairment and waitlist mortality differed by diabetes status kidney transplantation rates (Pinteraction=0.02). Among candidates without diabetes, those with cognitive impairment were at 2.47 (95% CI, 1.31-4.66) times greater risk for waitlist mortality; cognitive impairment was not associated with this outcome among candidates with diabetes.

LIMITATIONS

Single measure of cognitive impairment.

CONCLUSIONS

Cognitive impairment is associated with a lower chance of being placed on the waitlist, and among patients without diabetes, with increased mortality on the waitlist. Future studies should investigate whether implementation of screening for cognitive impairment improves these outcomes.

Development and Validation of a Nomogram for Predicting the 6-Year Risk of Cognitive Impairment Among Chinese Older Adults

OBJECTIVE

Although some people with mild cognitive impairment may not suffer from dementia lifelong, about 5% of them will progress to dementia within 1 year in community settings. However, a general tool for predicting the risk of cognitive impairment was not adequately studied among older adults.

DESIGN

Prospective cohort study.

SETTING

Community-living, older adults from 22 provinces in China.

PARTICIPANTS

We included 10,066 older adults aged 65 years and above (mean age, 83.2 ± 11.1 years), with normal cognition at baseline in the 2002-2008 cohort and 9354 older adults (mean age, 83.5 ± 10.8 years) in the 2008-2014 cohort of the Chinese Longitudinal Healthy Longevity Survey.

METHODS

We measured cognitive function using the Chinese version of the Mini-Mental State Examination. Demographic, medical, and lifestyle information was used to develop the nomogram via a Lasso selection procedure using a Cox proportional hazards regression model. We validated the nomogram internally with 2000 bootstrap resamples and externally in a later cohort. The predictive accuracy and discriminative ability of the nomogram were measured by area-under-the-curves and calibration curves, respectively.

RESULTS

Eight factors were identified with which to construct the nomogram: age, baseline of the Mini-Mental State Examination, activities of daily living and instrumental activities of daily living score, chewing ability, visual function, history of stroke, watching TV or listening to the radio, and growing flowers or raising pets. The area-under-the-curves for internal and external validation were 0.891 and 0.867, respectively, for predicting incident cognitive impairment. The calibration curves showed good consistency between nomogram-based predictions and observations.

CONCLUSIONS AND IMPLICATIONS

The nomogram-based prediction yielded consistent results in 2 separate large cohorts. This feasible prognostic nomogram constructed using readily ascertained information may assist public health practitioners or physicians to provide preventive interventions of cognitive impairment.

Association of Prediabetes and Type 2 Diabetes With Cognitive Function After Stroke: A STROKOG Collaboration Study

Background and Purpose- Type 2 diabetes mellitus (T2D) is associated with cognitive impairment and an increased risk of dementia, but the association between prediabetes and cognitive impairment is less clear, particularly in a setting of major cerebrovascular events. This article examines the impact of impaired fasting glucose and T2D on cognitive performance in a stroke population. Methods- Seven international observational studies from the STROKOG (Stroke and Cognition) consortium (n=1601; mean age, 66.0 years; 70% Asian, 26% white, and 2.6% African American) were included. Fasting glucose level (FGL) during hospitalization was used to define 3 groups, T2D (FGL ≥7.0 mmol/L), impaired fasting glucose (FGL 6.1-6.9 mmol/L), and normal (FGL <6.1 mmol/L), and a history of diabetes mellitus and the use of a diabetes mellitus medication were also used to support a diagnosis of T2D. Domain and global cognition Z scores were derived from standardized neuropsychological test scores. The cross-sectional association between glucose status and cognitive performance at 3 to 6 months poststroke was examined using linear mixed models, adjusting for age, sex, education, stroke type, ethnicity, and vascular risk factors. Results- Patients with T2D had significantly poorer performance in global cognition (SD, -0.59 [95% CI, -0.82 to -0.36]; P<0.001) and in all domains compared with patients with normal FGL. There was no significant difference between impaired fasting glucose patients and those with normal FGL in global cognition (SD, -0.10 [95% CI, -0.45 to 0.24]; P=0.55) or in any cognitive domain. Conclusions- Diabetes mellitus, but not prediabetes, is associated with poorer cognitive performance in patients 3 to 6 months after stroke.

Sex-Related Differences in Brain Volumes and Cerebral Blood Flow Among Overweight and Obese Adults With Type 2 Diabetes: Exploratory Analyses From the Action for Health in Diabetes Brain Magnetic Resonance Imaging Study

BACKGROUND

Sex may be an important modifier of brain health in response to risk factors. We compared brain structure and function of older overweight and obese women and men with type 2 diabetes mellitus.

METHODS

Cross-sectional cognitive assessments and magnetic resonance images were obtained in 224 women and 95 men (mean age 69 years) with histories of type 2 diabetes mellitus and overweight or obesity. Prior to magnetic resonance images, participants had completed an average of 10 years of random assignment to either multidomain intervention targeting weight loss or a control condition of diabetes support and education. Total (summed gray and white) matter volumes, white matter hyperintensity volumes, and cerebral blood flow across five brain regions of interest were analyzed using mixed-effects models.

RESULTS

After covariate adjustment, women, compared with men, averaged 10.9 [95% confidence interval 3.3, 18.5; ≈1%] cc greater summed region of interest volumes and 1.39 [0.00002, 2.78; ≈54%] cc greater summed white matter hyperintensity volumes. Sex differences could not be attributed to risk factor profiles or intervention response. Their magnitude did not vary significantly with respect to age, body mass index, intervention assignment, or APOE-ε4 genotype. Sex differences in brain magnetic resonance images outcomes did not account for the better levels of cognitive functioning in women than men.

CONCLUSIONS

In a large cohort of older overweight or obese adults with type 2 diabetes mellitus, differences in brain volumes and white matter disease were apparent between women and men, but these did not account for a lower prevalence of cognitive impairment in women compared with men in this cohort.

TRIAL REGISTRATION

NCT00017953.