Physical activity as a protective factor for dementia and Alzheimer's disease: systematic review, meta-analysis and quality assessment of cohort and case-control studies

Life-Course Multidisciplinary Psychosocial Predictors of Dementia Among Older Adults: Results From the Health and Retirement Study

Background and Objectives

Identifying predictors of dementia may help improve risk assessments, increase awareness for risk reduction, and identify potential targets for interventions. We use a life-course psychosocial multidisciplinary modeling framework to examine leading predictors of dementia incidence.

Research Design and Methods

We use data from the Health and Retirement Study to measure 57 psychosocial factors across 7 different domains: (i) demographics, (ii) childhood experiences, (iii) socioeconomic conditions, (iv) health behaviors, (v) social connections, (vi) psychological characteristics, and (vii) adverse adulthood experiences. Our outcome is dementia incidence (over 8 years) operationalized using Langa-Weir classification for adults aged 65+ years who meet criteria for normal cognition at the baseline when all psychosocial factors are measured (N = 1 784 in training set and N = 1 611 in testing set). We compare the standard statistical method (Logistic regression) with machine learning (ML) method (Random Forest) in identifying predictors across the disciplines of interest.

Results

Standard and ML methods identified predictors that spanned multiple disciplines. The standard statistical methods identified lower education and childhood financial duress as among the leading predictors of dementia incidence. The ML method differed in their identification of predictors.

Discussion and Implications

The findings emphasize the importance of upstream risk and protective factors and the long-reaching impact of childhood experiences on cognitive health. The ML approach highlights the importance of life-course multidisciplinary frameworks for improving evidence-based interventions for dementia. Further investigations are needed to identify how complex interactions of life-course factors can be addressed through interventions.

Effects of treadmill exercise on endoplasmic reticulum protein folding and endoplasmic reticulum-associated protein degradation pathways in APP/PS1 mice

A hallmark of Alzheimer's disease (AD) is the disruption of protein homeostasis (proteostasis), manifested by the misfolding and aggregation of proteins. Molecular chaperones and the endoplasmic reticulum (ER)-associated protein degradation (ERAD) pathway in the ER are essential for correct protein folding and degradation of misfolded proteins respectively, thus contributing to the maintenance of proteostasis. The present study aimed to investigate whether the beneficial effects of exercise in an AD mice model is associated with changes in ER protein folding and ERAD. APP/PS1 transgenic and wild-type mice were subjected to treadmill exercise for three months. The levels of molecular chaperones, specifically protein disulfide isomerases (PDIs) and heat shock proteins (HSPs), as well as ERAD-associated molecules were analyzed in the hippocampus. The result revealed a decrease in mRNA levels of PDIA2, PDIA3, PDIA4, PDIA5, PDIA6, HSPA1B, HSPA8, HSP90B1, DNAJB2, CRYAB, and CNX, an increase in mRNA levels of HSPA5 and HSPH1, an increase in protein levels of HERPUD1, and a decrease in protein levels of VCP in APP/PS1 mice. However, following a 3-month treadmill exercise regimen, an increase in mRNA levels of PDIA2, PDIA4, PDIA6, HSPA1A, HSPA8, HSP90AB1, and DNAJB2, as well as an increase in protein levels of VCP and DERL2, and a decrease in protein levels of HERPUD1 were noted. Overall, our findings indicate that disruptions in hippocampal ER protein folding and ERAD pathways may be implicated in AD, with exercise serving as a regulator of these pathways.

SoccHealth: a health status examination of former professional football (soccer) players within the German National Cohort

The long-term health effects of football (soccer) have received significant attention in recent years. While brain health is currently the focus of this interest, potential long-term risks or benefits related to cardiovascular and metabolic diseases and cancer are also of interest to sports medicine professionals. However, studies assessing the overall health risks for professional football players remain scarce. We introduce 'SoccHealth', a satellite project to the German National Cohort (NAKO), Germany's largest population-based cohort study. SoccHealth examined 348 former professional football players aged 40-69 using the infrastructure and comprehensive examination programme of NAKO. The German Statutory Accidental Insurance for Professional Athletes identified and invited male players, while female players were recruited among former national team members. Details of the examination programme and the sociodemographic and career-related characteristics of the participants are described. The identical examination programme for the NAKO participants provides the opportunity to draw general population controls according to various definitions and focus on the respective research question to be analysed. This report delineates one approach to evaluate the long-term health effects of football across a broad range of diseases.

The impact of education as a proxy for lifestyle habits on reducing the association with dementia prevalence in the Southern Region of Brazil

Objectives

This study aimed to investigate the prevalence of dementia among older adults from Florianópolis, in the Southern Region of Brazil.

Methods

Data were originally drawn from the Epifloripa Aging Cohort Study, a representative and community-based survey designed to evaluate older people's health. This cross-sectional study was conducted in two phases: the community-screening phase, in which the Mini-Mental State Examination and a multifunctional scale were administered to older subjects and close informants, respectively; and the hospital-diagnosis phase, when the Cambridge Examination and the National Institute on Aging criteria were used. Adjustment for screening accuracy was made in order to estimate dementia prevalence.

Results

Of 1184 subjects evaluated in the community, 243 were screened for the diagnosis phase, in which 47 were identified with dementia, resulting in a crude prevalence of 4.5% (95% CI: 3.241-5.758) and an estimated prevalence of 9.2% (95% CI: 7.446-10.954). Dementia was associated with older ages, lower education levels, and the presence of stroke. Mild alcohol use (in comparison with no alcohol use), community-group practice, internet use and a higher level of physical activity, rather than education, decreased the odds ratio for dementia. Education was directly associated with these lifestyle habits.

Conclusions

Prevalence was lower than that in previous studies in the country, and multivariate analysis reinforced the importance of lifestyle in preventing cognitive disorders in the older population.

Accelerometer-derived 'weekend warrior' physical activity pattern and brain health

Extensive evidence shows the beneficial effect of adhering to a regular physical activity (PA) pattern on brain health. However, whether the 'weekend warrior' pattern, characterized by concentrated moderate-to-vigorous PA (MVPA) over 1-2 days, is associated with brain health is unclear. Here, we perform a prospective cohort study including 75,629 participants from the UK Biobank with validated accelerometry data. Individuals were classified into three PA patterns using current guideline thresholds: inactive (<150 min week-1 of MVPA), weekend warrior (≥150 min week-1 with ≥50% of total MVPA occurring within 1-2 days) and regularly active (≥150 min week-1 but not meeting weekend warrior criteria). We find that the weekend warrior pattern is associated with similarly lower risks of dementia, stroke, Parkinson's disease, depressive disorders and anxiety compared to a regularly active pattern. Our findings highlight the weekend warrior pattern as a potential alternative in preventive intervention strategies, particularly for those unable to maintain daily activity routines.

Best practice in dementia health care: Key clinical practice pointers from a national conference and innovative opportunities for pharmacy practice

OBJECTIVE

Sub-optimal care of people living with dementia has serious consequences for older populations. The 2021 Australian Royal Commission noted that a large proportion of older adults in aged care live with dementia, yet there are limitations in the knowledge and understanding of staff who care for them. In the pursuit of educating pharmacists, physicians, allied health care professionals, researchers, academics, people living with dementia and their carers, and the public, who are facing the challenges of dementia management, the 'Best Practice in Dementia Health Care' conference was held on November 10, 2022 at Western Health (Sunshine Hospital, Melbourne, Australia).

METHODS

Sixteen experts presented on the current practice and challenges associated with delivering best practice dementia health care to older Australians, often highlighting how medication-related challenges impacted on their area of practice.

RESULTS

Presenters highlighted the importance of individualised medication management plans, considerations of culture and Indigenous communities, the role of technology, and the impact of exercise and the physical environment on care of people living with dementia. Key clinical practice messages from each expert presenter fit into four main topics: 'navigating complexities of medication management'; 'enhancing wellbeing'; 'supportive settings and environments'; and 'programs and services improving care'.

CONCLUSIONS

Pharmacists are crucial members of allied health care teams. They have the necessary medication and comorbidity expertise to review medication regimens, liaise with all health care providers, and provide holistic, pharmacological and non-pharmacological patient education. Towards providing best practice dementia health care, pharmacists can contribute in several ways, such as providing health practitioner education to increase understanding about medications and how they can impact on allied health practice, to ensure that medications are prescribed appropriately and safely. Further, pharmacists can make available resources to ensure people living with dementia receive culturally safe and appropriate care, while advocating for greater understanding of the history and experiences of people living with dementia to ensure care aligns with their day-to-day routines. Finally, pharmacists can provide peer-support to other health care professionals and care staff to ensure optimal management of behavioural and psychological symptoms of dementia. The information and insights shared at the conference can serve as a valuable resource for pharmacists and other health care professionals and researchers working to improve the lives of those living with dementia.

Age differences in the moderating effects of neighbourhood disadvantage on the relationship between physical activity and cognitive function: A longitudinal analysis of the Canadian Longitudinal Study on Aging

OBJECTIVES

To explore whether the association between physical activity (PA) and cognition is moderated by neighbourhood disadvantage, and whether this relationship varies with age.

STUDY DESIGN

A longitudinal analysis of the Canadian Longitudinal Study on Aging, wherein we included participants (N = 41,599) from urban areas who did not change their residential postal code from baseline (2010-2015) to first follow-up (2015-2018).

MAIN OUTCOME MEASURES

At baseline, we measured PA using the Physical Activity Scale for the Elderly, and neighbourhood disadvantage using the Material and Social Deprivation Indices.

RESULTS

Using latent change score regression models, we determined that higher PA at baseline was independently associated with greater maintenance in memory performance from baseline to first follow-up both for adults aged 45-64 (B = 0.04, SE = 0.01, p = 0.001) and for those aged 65+ years (B = 0.12, SE = 0.02, p < 0.001). For participants aged 45-64 years, greater material deprivation was independently associated with declines in memory performance (B = -0.10, SE = 0.03, p < 0.001). In addition, greater social deprivation was associated with a stronger effect of PA on changes in executive functions (B = 0.17, SE = 0.08, p = 0.025) for adults aged 45-64 years; greater material deprivation was associated with a stronger effect of PA on changes in memory performance (B = 0.07, SE = 0.03, p = 0.022). We failed to detect any interactions between PA and neighbourhood disadvantage among adults aged 65+ years (all p values >0.05).

CONCLUSION

For middle-aged adults, the benefits of PA on cognitive performance may be strongest among adults living with greater neighbourhood social and material disadvantages. For older adults, PA may be beneficial to cognitive performance irrespective of neighbourhood disadvantages.

Sound and Alzheimer's Disease-From Harmful Noise to Beneficial Soundscape Augmentation and Music Therapy

Exposure to sound energy may be a risk factor or a therapeutic intervention for Alzheimer's disease (AD). On one hand, noise has a harmful effect on people with AD by contributing to hearing loss, sleep disturbance, oxidative stress, inflammation, and excitotoxicity. But on the other hand, clinical trials and nursing home interventions with soundscape augmentation involving natural sounds have shown promising results in alleviating psychophysiological symptoms in people with AD. Music therapy, an emerging non-pharmacological treatment, can improve cognition, reduce anxiety and depression, and enhance self-awareness in patients with AD. To ensure that music does not become noise in clinical trials, only favorite music at levels safe for hearing should be used. From a public health standpoint, noise countermeasures, soundscape augmentation with natural sounds, and active or passive engagement with music may be regarded as potentially powerful strategies for the prevention of AD.

Effects of Occupational and Leisure-Time Physical Activity on the Risk of Dementia: Results From the Copenhagen City Heart Study

Leisure-time physical activity (LTPA) decreases the risk of dementia, whereas occupational physical activity (OPA) possibly increases the risk. Yet, previous findings are mixed. We therefore aimed to investigate the effect of LTPA and OPA, respectively, on dementia among men and women. In this observational, longitudinal study, we used data from the second wave of a population-based cohort from the municipality of Copenhagen as baseline. Data were collected in 1981-1983, and 10 343 participants were followed until the end of 2016. LTPA and OPA were self-reported, and information on dementia diagnoses and redemption of dementia medication was obtained at an individual level from national health registers. We used Poisson regression to analyze the association between LTPA/OPA and dementia and adjusted for self-reported age, socioeconomic factors, stress, and cardiovascular risk factors (smoking, alcohol, body mass index, and blood pressure). A higher level of LTPA was associated with a lower dementia risk among men, but we found no clear association among women. OPA and dementia were not associated among men, but occupationally active women who reported OPA in terms of walking, lifting, and heavy work had a higher risk of dementia than women with sedentary jobs. This study supported earlier findings of a protective effect of LTPA on dementia among men. Women in physically demanding jobs possibly have a higher risk of dementia, yet this finding warrants further investigation in future studies.

Cardiorespiratory fitness, independent of APOE genotype, is associated with better neurocognitive function in older adults: An ERP study

This study assessed the association between cardiorespiratory fitness and carriage of the apolipoprotein-E ε4 (APOE ε4) alleles and cognitive function using behavioral and neuroelectric measures obtained from cognitively normal older adults. A total of 159 adults aged 50-70 years were categorized into four groups based on cardiorespiratory fitness (i.e., higher vs. lower fitness) and the APOE genotype status (i.e., APOE ε4 carrier vs. non-carrier). Neurocognitive functions were indexed using response time and accuracy measures from the Stroop task and averaged mean P3 amplitudes of event-related potentials obtained during task performance. A significant main effect of cardiorespiratory fitness (p = .01) and the Stroop congruency (p < .001), but not the APOE genotype status, with shorter response times for the higher fitness group than for the lower fitness group and for the congruent condition relative to the incongruent condition, were observed. Similar findings were also revealed, with larger averaged mean P3 amplitudes for the higher fitness group than those in the lower fitness group, and in the congruent condition than in the incongruent condition. These findings suggest that higher cardiorespiratory fitness is linked to better neurocognitive function, and the positive association is evident regardless of the APOE ε4 status and the cognitive domain assessed in cognitively normal older adults.

Physical activity and the risk of developing 8 age-related diseases: epidemiological and Mendelian randomization studies

BACKGROUND

We aimed to characterize the associations between physical activity levels and the risk of developing age-related diseases in the Coronary Artery Risk Development in Young Adults (CARDIA) study and used Mendelian randomization (MR) to assess whether there are causal relationships between physical activity levels and the risk of developing 8 age-related diseases (coronary atherosclerosis, ischemic heart disease, angina, Alzheimer's disease, hypertension, type 2 diabetes, hyperlipidemia, and venous thromboembolism).

METHODS

Based on the data available in the CARDIA, we obtained data related to five disease states: coronary heart disease, hypertension, diabetes, hyperlipidemia, and venous thromboembolism. Binary logistic regression analysis estimated the multivariable-adjusted associations between different physical activity statuses and diseases. For the MR study, we used summary-level data from a recently published genome-wide association study on physical activity (including vigorous physical activity and accelerometer-based physical activity) conducted with participants from the UK Biobank study. We selected the above 8 age-related diseases as our outcomes.

RESULTS

In the CARDIA-based analysis, the risk of developing coronary heart disease [OR (95% CI): 0.562 (0.397-0.795)], hypertension [OR (95% CI): 0.703 (0.601-0.821)], diabetes [OR (95% CI): 0.783 (0.620-0.988)], and hyperlipidemia [OR (95% CI): 0.792 (0.662-0.949)] was negatively related to physical activity status when participants achieved the physical activity target. Our MR results support a negative causal association between genetically determined vigorous physical activity levels and the risk of developing 3 age-related diseases, namely, angina, hypertension and type 2 diabetes. Moreover, our results also support a negative causal association between genetically determined accelerometer-based physical activity levels and the risk of developing angina.

CONCLUSIONS

Promotion of physical activity is likely to prevent specific age-related diseases.

Hindlimb immobilization induces insulin resistance and elevates mitochondrial ROS production in the hippocampus of female rats

Alzheimer's disease (AD) is the fifth leading cause of death in older adults, and treatment options are severely lacking. Recent findings demonstrate a strong relationship between skeletal muscle and cognitive function, with evidence supporting that muscle quality and cognitive function are positively correlated in older adults. Conversely, decreased muscle function is associated with a threefold increased risk of cognitive decline. Based on these observations, the purpose of this study was to investigate the negative effects of muscle disuse [via a model of hindlimb immobilization (HLI)] on hippocampal insulin sensitivity and mitochondrial function and identify the potential mechanisms involved. HLI for 10 days in 4-mo-old female Wistar rats resulted in the following novel findings: 1) hippocampal insulin resistance and deficits in whole body glucose homeostasis, 2) dramatically increased mitochondrial reactive oxygen species (ROS) production in the hippocampus, 3) elevated markers for amyloidogenic cleavage of amyloid precursor protein (APP) and tau protein in the hippocampus, 4) and reduced brain-derived neurotrophic factor (BDNF) expression. These findings were associated with global changes in iron homeostasis, with muscle disuse producing muscle iron accumulation in association with decreased serum and whole brain iron levels. We report the novel finding that muscle disuse alters brain iron homeostasis and reveal a strong negative correlation between muscle and brain iron content. Overall, HLI-induced muscle disuse has robust negative effects on hippocampal insulin sensitivity and ROS production in association with altered brain iron homeostasis. This work provides potential novel mechanisms that may help explain how loss of muscle function contributes to cognitive decline and AD risk.NEW & NOTEWORTHY Muscle disuse via hindlimb immobilization increased oxidative stress and insulin resistance in the hippocampus. These findings were in association with muscle iron overload in connection with iron dysregulation in the brain. Overall, our work identifies muscle disuse as a contributor to hippocampal dysfunction, potentially through an iron-based muscle-brain axis, highlighting iron dysregulation as a potential novel mechanism in the relationship between muscle health, cognitive function, and Alzheimer's disease risk.

Effect of long-term physical exercise and multidomain interventions on cognitive function and the risk of mild cognitive impairment and dementia in older adults: A systematic review with meta-analysis

INTRODUCTION

Recent studies have suggested that sustained multidomain interventions, including physical exercise, may be beneficial in preventing cognitive decline. This review aims to assess the impact of prolonged physical exercise and multidomain strategies on overall cognitive faculties and dementia risk among community-dwelling older adults without dementia.

METHODS

We systematically searched PubMed, Web of Science, PsychInfo, and CINHAL databases from inception until April 1, 2024, for randomized controlled trials that investigated the effects of long-term (≥ 12 months) physical exercise or multidomain interventions on non-demented, community-dwelling older adults. The primary outcomes assessed were changes in global cognition and the risk of mild cognitive impairment (MCI) or dementia. Standardized mean differences (SMD) and risk ratios (RR) with 95 % confidence intervals were computed using a random-effects inverse-variance method with the Hartung-Knapp-Sidik-Jonkman adjustment for effect size calculation. The Cochrane Risk-of-Bias-2 tool (RoB-2) was used for bias assessment, and the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) approach was applied to evaluate the certainty of evidence.

RESULTS

Sixteen trials, including 11,402 participants (mean age 73.2 [±5.5] years; 62.3 % female) were examined. The risk of bias was low. Moderate-certainty evidence indicated that physical exercise interventions had modest to no effect on cognitive function (k= 9, SMD: 0.05; 95 % CI: -0.04-0.13; p = 0.25), whereas multidomain interventions were significantly impactful (k=7, SMD: 0.09; 95 % CI: 0.04-0.15; p < 0.01). Physical exercise interventions did not alter MCI risk (k= 4, RR: 0.98; 95 % CI: 0.73-1.31; p = 0.79) or dementia onset (k= 4, RR: 0.61; 95 % CI: 0.25-1.52; p = 0.19), with very low-to low-certainty evidence, respectively.

CONCLUSIONS

Integrative multidomain strategies incorporating physical exercise may benefit the global cognitive function of older adults. However, long-term physical exercise alone did not yield any cognitive gains. The effectiveness of such exercise interventions to mitigate the overall risk of incident MCI and dementia warrants further research.

Association of 24-Hour movement behavior and cognitive function in older Taiwanese adults

OBJECTIVES

This study investigates how 24-hour movement behaviors (physical activity, sedentary time, sleep) relate to cognitive performance in older adults.

METHODS

213 adults (aged 65+) wore accelerometers to track activity. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). Isotemporal substitution analysis examined how replacing one behavior with another affected cognition.

RESULTS

Increased light physical activity was linked to better cognitive function, whereas longer sleep had a negative impact. Replacing 30 min of sedentary behavior or sleep with light physical activity improved orientation, attention, language, and short-term memory. Substituting moderate-to-vigorous physical activity did not have the same cognitive benefit.

CONCLUSION

Encouraging older adults to replace sedentary time or excess sleep with light physical activity could support cognitive health and potentially help prevent dementia. These findings have implications for public health strategies promoting cognitive well-being in aging populations.

Physical activity modification over time according to socioeconomic position: results from the EPIC-Italy cohort study

Objectives

Our study aimed to investigate how physical activity (PA) changes over an 11-year follow-up among adults from different socioeconomic positions (SEP) near retirement age. Moreover, an analysis of different PA types is considered.

Methods

We used data from the EPIC-Italy cohort. We evaluated PA using the Cambridge Physical Activity Index (CPAI) and the metabolic equivalent of tasks (MET) per hour of activity for recreational PA and household PA. Educational level was assessed using the Relative Index of Inequality (RII). Occupational classes were classified according to LIFEPATH Consortium knowledge. Logistic regression was used to analyse PA among SEP and changes during follow-up. Analyses were also conducted separately for sex.

Results

The higher educated were more prevalent in the higher quartile of recreational PA than the lower educated both at baseline and follow-up (37% vs 28% and 37% vs 27%, respectively). At the baseline, the lower educated had a higher risk of being physically inactive than the higher educated based on recreational PA (overall OR: 1.50, 95% CI 1.40 to 1.60). Manual workers did not show a higher risk of less PA than professionals/managers (overall OR: 1.03, 95% CI 0.91 to 1.16).At follow-up, the lower educated and manual workers showed a higher risk of being physically inactive (lower educated OR: 1.46, 95% CI 1.37 to 1.56; manual worker OR: 1.33, 95% CI 1.18 to 1.50). The analyses of changes in PA showed that those who were less educated or manual workers had a higher risk of worsening their PA during the follow-up period, particularly women in recreational PA and men in CPAI measurement.

Conclusion

Individuals who had a disadvantaged SEP showed a higher risk of performing less PA over time.

Lifestyle Changes in Aging and their Potential Impact on POAG

Primary open angle glaucoma is a primary mitochondrial disease with oxidative stress triggering neuroinflammation, eventually resulting in neurodegeneration. This affects many other areas of the brain in addition to the visual system. Aging also leads to inflammaging - a low-grade chronic inflammatory reaction in mitochondrial dysfunction, so these inflammatory processes overlap in the aging process and intensify pathophysiological processes associated with glaucoma. Actively counteracting these inflammatory events involves optimising treatment for any manifest systemic diseases while maintaining chronobiology and improving the microbiome. Physical and mental activity also provides support. This requires a holistic approach towards optimising neurodegeneration treatment in primary open angle glaucoma in addition to reducing intraocular pressure according personalised patient targets.

The impact of physical exercise on neuroinflammation mechanism in Alzheimer's disease

Introduction

Alzheimer's disease (AD), a major cause of dementia globally, imposes significant societal and personal costs. This review explores the efficacy of physical exercise as a non-pharmacological intervention to mitigate the impacts of AD.

Methods

This review draws on recent studies that investigate the effects of physical exercise on neuroinflammation and neuronal enhancement in individuals with AD.

Results

Consistent physical exercise alters neuroinflammatory pathways, enhances cognitive functions, and bolsters brain health among AD patients. It favorably influences the activation states of microglia and astrocytes, fortifies the integrity of the blood-brain barrier, and attenuates gut inflammation associated with AD. These changes are associated with substantial improvements in cognitive performance and brain health indicators.

Discussion

The findings underscore the potential of integrating physical exercise into comprehensive AD management strategies. Emphasizing the necessity for further research, this review advocates for the refinement of exercise regimens to maximize their enduring benefits in decelerating the progression of AD.

Estrogen Receptors: A New Frontier in Alzheimer's Disease Therapy

Alzheimer's disease (AD) is a long-term neurodegenerative condition that leads to the deterioration of neurons and synapses in the cerebral cortex, resulting in severe dementia. AD is significantly more prevalent in postmenopausal women, suggesting a neuroprotective role for estrogen. Estrogen is now known to regulate a wide array of physiological functions in the body by interacting with three known estrogen receptors (ERs) and with the β-amyloid precursor protein, a key factor in AD pathogenesis. Recent experimental evidence indicates that new selective ER modulators and phytoestrogens may be promising treatments for AD for their neuroprotective and anti-apoptotic properties. These alternatives may offer fewer side effects compared to traditional hormone therapies, which are associated with risks such as cardiovascular diseases, cancer, and metabolic dysfunctions. This review sheds light on estrogen-based treatments that may help to partially prevent or control the neurodegenerative processes characteristic of AD, paving the way for further investigation in the development of estrogen-based treatments.

Effect of hypoglycemic events on cognitive function in individuals with type 2 diabetes mellitus: a dose-response meta-analysis

Background

Type 2 diabetes mellitus (T2DM) is widely acknowledged as a vital warning sign contributing to cognitive dysfunction. However, there is still a lack of consensus on whether hypoglycemic events resulting from poor glycemic control increase the risk of cognitive dysfunction in people with diabetes, and the potential dose-response correlation between hypoglycemic events and cognitive dysfunction remains unexplored. The primary objective of the current study was to assess the contribution of hypoglycemic events to cognitive dysfunction in T2DM patients and the dose-response correlation between the two.

Methods

A comprehensive search of nine major databases was executed from inception to May 2023. We screened all observational studies examining the connection between hypoglycemia and cognitive dysfunction. The DerSimonian-Laird method was used to compute the combined risk ratio (RR) and its 95% confidence interval (CI). Additionally, dose-response analysis was employed to investigate the correlation between the frequency of hypoglycemia and the likelihood of cognitive dysfunction.

Results

A total of 30 studies of different levels in 17 articles with 3,961,352 participants were included in this review. The pooled RR for the connection of hypoglycemia and the likelihood of cognitive dysfunction was 1.47 (95% CI: 1.35-1.60). Subgroup analyses showed that the pooled RR for the likelihood of cognitive dysfunction was 1.20 (95% CI: 1.11-1.31) for one episode of hypoglycemia, 1.41 (95% CI: 1.05-1.88) for two episodes of hypoglycemia, and 1.62 (95% CI: 1.20-2.91) for three or more episodes of hypoglycemia. Dose-response analysis showed a linear dose-response relationship between hypoglycemia and the likelihood of cognitive dysfunction (exp (b) = 1.178694, z = 7.12, p < 0.001).

Conclusion

Our investigations demonstrated a 47% heightened likelihood of cognitive dysfunction in individuals with hypoglycemia compared to those without. Furthermore, the likelihood of cognitive dysfunction climbed by 17.87% for every subsequent episode of hypoglycemia. Therefore, long-term monitoring of blood glucose, periodic screening of cognitive function, and moderate health education should be encouraged, which will be beneficial for people with diabetes to prevent hypoglycemic events and cognitive dysfunction.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, CRD42023432352.

Perimenopausal Physical Activity and Dementia Risk: A Systematic Review

Mixed-gender studies predominate in the current literature exploring the interaction between physical activity and dementia risk. Considering that menopause appears to contribute to females' increased risk of cognitive decline when compared to males, further clarity is required on the impact of physical activity in reducing late-life dementia risk, specifically in perimenopausal females. A literature search of MEDLINE, EMBASE, Web of Science, SCOPUS and CINAHL databases yielded fourteen studies for review. A significant inverse relationship between perimenopausal leisure time physical activity, or physical fitness, and future all-cause dementia risk was found in most studies exploring this interaction. Higher levels of perimenopausal household physical activity and combined non-leisure time physical activity also displayed a favorable impact in lowering dementia risk. A dose-response effect was demonstrated, with approximately 10 MET-hour/week of leisure time physical activity required for significant dementia risk reduction. Three of four papers exploring causality provided analyses proposed to counter the reverse causation argument, suggesting that physical activity may indeed have a protective role in reducing dementia risk post-menopause. The current systematic review provides promising results regarding the impact of pre- and perimenopausal physical activity on reducing late-life dementia risk, suggesting that promoting perimenopausal physical activity may serve as a crucial tool in mitigating the risk of post-menopausal cognitive decline.

Associations of ambient air pollution exposure and lifestyle factors with incident dementia in the elderly: A prospective study in the UK Biobank

OBJECTIVE

Dementia is an important disease burden among the elderly, and its occurrence may be profoundly affected by environmental factors. Evidence of the relationship between air pollution and dementia is emerging, but the extent to which this can be offset by lifestyle factors remains ambiguous.

METHODS

This study comprised 155,828 elder adults aged 60 years and above in the UK Biobank who were dementia-free at baseline. Cox proportional hazard models were conducted to examine the associations of annual average levels of air pollutants in 2010, including nitrogen dioxide (NO2), nitrogen oxides (NOX), particulate matter (PM2.5, PM10, and PMcoarse) and lifestyle factors recorded at baseline [physical activity (PA), sleep patterns, or smoking status] with incident risk of dementia, and their interactions on both multiplicative and additive scales.

RESULTS

During a 12-year period of follow-up, 4,389 incidents of all-cause dementia were identified. For each standarddeviationincrease in ambient NO2, NOX or PM2.5, all-cause dementia risk increases by 1.07-fold [hazard ratio (HR) and 95 % confidence interval (CI) = 1.07 (1.04, 1.10)], 1.05-fold (95 % CI: 1.02, 1.08) and 1.07-fold (95 % CI: 1.04, 1.10), whereas low levels of PA, poor sleep patterns, and smoking are associated with an elevated risk of dementia [HR (95 % CI) = 1.17 (1.09, 1.26), 1.13 (1.00, 1.27), and 1.14 (1.07, 1.21), respectively]. Furthermore, these air pollutants show joint effects with low PA, poor sleep patterns, and smoking on the onset of dementia. The moderate to high levels of PA could significantly or marginally significantly modify the associations between NO2, NOX or PM2.5 (P-int = 0.067, 0.036, and 0.067, respectively) and Alzheimer's disease (AD), but no significant modification effects are found for sleep patterns or smoking status.

CONCLUSION

The increased exposures of NO2, NOX, or PM2.5 are associated with elevated risk of dementia among elderly UK Biobank population. These air pollutants take joint effects with low PA, poor sleep patterns, and smoking on the development of dementia. In addition, moderate to high levels of PA could attenuate the incident risk of AD caused by air pollution. Further prospective researches among other cohort populations are warranted to validate these findings.

Combined healthy lifestyle behaviours and incident dementia: A systematic review and dose-response meta-analysis of cohort studies

BACKGROUND

The associations of combined healthy lifestyle behaviours and incident dementia have not been systematically reviewed and the dose-response relationship was uncertain.

OBJECTIVES

To evaluate the associations of combined healthy lifestyle behaviours with incident dementia and other cognitive outcomes, assess the dose-response relationship between the number of lifestyle behaviours and incident dementia, and summarise the adherence to healthy lifestyle behaviours.

DESIGN

Systematic review and meta-analysis.

METHODS

PubMed, EMBASE, Web of Science and PsycINFO were searched from inception to 20 Jan 2024. Cohort studies reporting associations of combined healthy lifestyle behaviours with incident dementia or other cognitive outcomes were included. We used the random-effects meta-analysis to pool the risk estimates and the robust error meta-regression method to examine the dose-response relationship. The methodological quality was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 22 articles including 25 cohort studies mostly from high-income economics were included, with all assessed as high methodological quality. Adherence to a healthy lifestyle was associated with a decreased risk of incident dementia, either per healthy lifestyle behaviour increase (pooled hazard ratio 0.89, 95 % confidence interval 0.85-0.94) or the highest level versus the lowest level (pooled hazard ratio 0.61, 95 % confidence interval 0.49-0.76). An inverse, linear dose-response relationship (Pnon-linear = 0.845) between the number of healthy lifestyle behaviours and incident dementia was observed, with an 11 % risk reduction for each healthy behaviour increase. A relatively limited number of included studies indicated that adherence to a healthy lifestyle combination could yield benefits for cognitive decline, global cognition, memory and executive function. In addition, the adherence rates typically decreased as the number of healthy lifestyle behaviours increased.

CONCLUSIONS

Adherence to a healthy lifestyle was associated with a lower risk of incident dementia and other cognitive outcomes. It is important to find a subtle balance between the benefits and adherence. Further large cohort studies for combined lifestyle behaviours with specific cognitive outcomes and dose-response relationships are required, especially based on middle- and low-income populations.

REGISTRATION

The study was registered in PROSPERO (CRD42023418509).

TWEETABLE ABSTRACT

Engaging in a greater number of healthy lifestyle behaviours yields increased benefits in preventing dementia, albeit with lower adherence rates as a trade-off. Finding a delicate balance between the benefits and adherence is crucial.

Longitudinal Patterns of Systolic Blood Pressure, Diastolic Blood Pressure, Cardiorespiratory Fitness, and Their Association With Dementia Risk: The HUNT Study

BACKGROUND

High blood pressure and poor cardiorespiratory fitness are independent risk factors for dementia. However, few studies have examined if combined longitudinal patterns of these modifiable risk factors are associated with dementia risk.

METHODS

In this prospective cohort study, we used data from the population-based Trøndelag Health (HUNT) Study, Norway. We applied group-based multidimensional trajectory modeling to identify age-specific multidimensional trajectories of SBP, DBP, and estimated cardiorespiratory fitness across 3 surveys (HUNT1, 1984-1986 to HUNT3, 2006-2008). Dementia was diagnosed in the HUNT4 70+ substudy in 2017-2019. We used multivariate logistic regression to estimate odds ratios (ORs) and risk differences (RDs) of dementia.

RESULTS

In total, 7 594 participants (54.9% women) were included, with a mean age of 44.7 (SD 6.3) years at HUNT1. Dementia was diagnosed in 1 062 (14.0%) participants. We identified 2 multidimensional trajectories throughout adulthood within 3 age groups: one with higher systolic blood pressure (SBP) and diastolic blood pressure (DBP), and lower estimated cardiorespiratory fitness (the poorer group), and one with lower SBP and DBP, and higher cardiorespiratory fitness (the better group). After adjustment for sex, apolipoprotein E ε4 status, education, marital status, and diabetes, the better group had consistently lower risk of dementia in all age groups with the lowest OR in the middle-aged group of 0.63 (95% confidence intervals [95% CI]: 0.51, 0.78) with corresponding RD of -0.07 (95% CI: -0.10, -0.04).

CONCLUSIONS

Having a beneficial multidimensional trajectory of SBP, DBP, and cardiorespiratory fitness in adulthood was associated with reduced dementia risk. Aiming for optimal SBP, DBP, and estimated cardiorespiratory fitness throughout adulthood may reduce dementia risk.

Melatonin improves cognitive dysfunction and decreases gliosis in the streptozotocin-induced rat model of sporadic Alzheimer's disease

Introduction

Alzheimer's disease (AD) and other forms of dementia have a devastating effect on the community and healthcare system, as neurodegenerative diseases are causing disability and dependency in older population. Pharmacological treatment options are limited to symptomatic alleviation of cholinergic deficit and accelerated clearance of β-amyloid aggregates, but accessible disease-modifying interventions are needed especially in the early phase of AD. Melatonin was previously demonstrated to improve cognitive function in clinical setting and experimental studies also.

Methods

In this study, the influence of melatonin supplementation was studied on behavioral parameters and morphological aspects of the hippocampus and amygdala of rats. Streptozotocin (STZ) was injected intracerebroventricularly to induce AD-like symptoms in male adult Wistar rats (n = 18) which were compared to age-matched, sham-operated animals (n = 16). Melatonin was administered once daily in a dose of 20 mg/kg body weight by oral route. Behavioral analysis included open-field, novel object recognition, and radial-arm maze tests. TNF-α and MMP-9 levels were determined from blood samples to assess the anti-inflammatory and neuroprotective effects of melatonin. Immunohistological staining of brain sections was performed using anti-NeuN, anti-IBA-1, and anti-GFAP primary antibodies to evaluate the cellular reorganization of hippocampus.

Results and Discussion

The results show that after 40 days of treatment, melatonin improved the cognitive performance of STZ-induced rats and reduced the activation of microglia in both CA1 and CA3 regions of the hippocampus. STZ-injected animals had higher levels of GFAP-labeled astrocytes in the CA1 region, but melatonin treatment reduced this to that of the control group. In conclusion, melatonin may be a potential therapeutic option for treating AD-like cognitive decline and neuroinflammation.

Cross-sectional study of cognitive impairment and visual impairment among the elderly population in residential care in India: the Hyderabad Ocular Morbidity in Elderly Study (HOMES)

OBJECTIVE

To report the relationship between visual impairment (VI) and cognitive impairment (CI) among the older population living in residential care homes in Hyderabad, India.

STUDY DESIGN

Cross-sectional study.

SETTING

41 homes for the aged centres in the Hyderabad region.

PARTICIPANTS

965 participants aged ≥60 years from homes for the aged centres.

PRIMARY OUTCOME MEASURES

Visual impairment and cognitive impairment.

METHODS

The Hindi mini-Mental Status Examination (HMSE) questionnaire was used to assess the cognitive function. The final HMSE score was calculated after excluding vision-dependent tasks (HMSE-VI). A detailed eye examination was conducted, including visual acuity (VA) measurement for distance and near vision, using a standard logarithm of the minimum angle of resolution chart under good illumination. CI was defined as having a HMSE-VI score of ≤17. VI was defined as presenting VA worse than 6/12 in the better-seeing eye. Near VI (NVI) was defined as binocular presenting near vision worse than N8 and distance VA of 6/18 or better in the better-seeing eye. Multiple logistic regression was done to assess the association between VI and CI.

RESULTS

The mean age (±SD) was 74.3 (±8.3) years (range: 60-97 years). There were 612 (63.4%) women, and 593 (61.5%) had a school education. In total, 260 (26.9%; 95% confidence intervals: 24.2 to 29.9) participants had CI. The prevalence of CI among those with VI was 40.5% compared with 14.6% among those without VI (p<0.01). The logistic regression analysis showed that the participants with VI for distance vision had three times higher odds of having CI (OR 3.09; 95% confidence intervals: 2.13 to 4.47; p<0.01). Similarly, participants with NVI had two times higher odds of having CI (OR 2.11; 95% confidence intervals: 1.36 to 3.29; p<0.01) after adjusting for other covariates.

CONCLUSIONS

CI was highly prevalent among those with distance and near VI. VI was independently and positively associated with CI after adjusting for potential confounders. Interventions can be planned to address VI in this vulnerable population which could have a ripple effect in preventing cognitive decline.

Effect of vigorous-intensity physical activity on incident cognitive impairment in high-risk hypertension

INTRODUCTION

We investigated the effect vigorous physical activity (VPA) on the risk of incident mild cognitive impairment (MCI) and probable dementia among individuals with high-risk hypertension.

METHODS

Baseline self-reported frequency of VPA was categorized into low VPA (<1 session/week), and high VPA (≥1 session/week). We used multivariate Cox regression analysis to examine the association of VPA categories with incident MCI and probable dementia events.

RESULTS

Participants in the high VPA category, compared with low VPA, experienced lower events rates (per 1000 person-years) of MCI (13.9 vs 19.7), probable dementia (6.3 vs 9.0), and MCI/probable dementia (18.5 vs 25.8). In the multivariate Cox regression model, high VPA, compared with low VPA, was associated with lower risk of MCI, probable dementia, and MCI/probable dementia (HR [95% CI]: 0.81 [0.68-0.97], 0.80 [0.63-1.03], and 0.82 [0.70-0.96]), respectively.

DISCUSSION

This study provides evidence that VPA may preserve cognitive function in high-risk patients with hypertension.

HIGHLIGHTS

Hypertension is associated with an increased risk of cognitive impairment Physical activity (PA) is associated with a lower risk of decline in cognition The effect of ≥1 sessions of vigorous-intensity PA (VPA) per week was assessed This analysis included SPRINT MIND trial participants with high-risk hypertension ≥1 VPA sessions/week was associated with lower risk of future cognitive impairment.

Transcranial Direct Current Stimulation to Ameliorate Post-Stroke Cognitive Impairment

Post-stroke cognitive impairment is a common and disabling condition with few effective therapeutic options. After stroke, neural reorganization and other neuroplastic processes occur in response to ischemic injury, which can result in clinical improvement through spontaneous recovery. Neuromodulation through transcranial direct current stimulation (tDCS) is a promising intervention to augment underlying neuroplasticity in order to improve cognitive function. This form of neuromodulation leverages mechanisms of neuroplasticity post-stroke to optimize neural reorganization and improve function. In this review, we summarize the current state of cognitive neurorehabilitation post-stroke, the practical features of tDCS, its uses in stroke-related cognitive impairment across cognitive domains, and special considerations for the use of tDCS in the post-stroke patient population.

Mind the Metabolic Gap: Bridging Migraine and Alzheimer's disease through Brain Insulin Resistance

Brain insulin resistance has recently been described as a metabolic abnormality of brain glucose homeostasis that has been proven to downregulate insulin receptors, both in astrocytes and neurons, triggering a reduction in glucose uptake and glycogen synthesis. This condition may generate a mismatch between brain's energy reserve and expenditure, ??mainly during high metabolic demand, which could be involved in the chronification of migraine and, in the long run, at least in certain subsets of patients, in the prodromic phase of Alzheimer's disease, along a putative metabolic physiopathological continuum. Indeed, the persistent disruption of glucose homeostasis and energy supply to neurons may eventually impair protein folding, an energy-requiring process, promoting pathological changes in Alzheimer's disease, such as amyloid-β deposition and tau hyperphosphorylation. Hopefully, the "neuroenergetic hypothesis" presented herein will provide further insight on there being a conceivable metabolic bridge between chronic migraine and Alzheimer's disease, elucidating novel potential targets for the prophylactic treatment of both diseases.

Physical activity, sedentary behaviour, and cognitive function among older adults: A bibliometric analysis from 2004 to 2024

Because of population ageing, there will be a vast increase in the prevalence of cognitive decline and dementia. Physical activity and sedentary behaviour have been identified as modifiable lifestyle behaviours associated with these cognitive conditions. Therefore, the aim of this bibliometric analysis is to reveal the knowledge structure of the field of physical activity, sedentary behaviour, and cognitive function among older adults from 2004 to 2024, and to predict emerging research trends. A total of 1290 publications were retrieved from the Web of Science Core Collection. CiteSpace and VOSviewer were applied to conduct performance analysis, science mapping, and enrichment. T. Liu-Ambrose was the most prolific author (39 publications), and the University of British Columbia was the most prolific institution (48 publications). The USA, China, and Canada were the three most productive countries with 392, 174, and 136 publications respectively. Two research trends revealed the knowledge structure of this field, including the shift from evaluating the effectiveness of interventions on cognitive function to evaluating the effectiveness of interventions on other health-related outcomes, as well as an expansion of research on the role of physical activity and sedentary behaviour in the context of healthy ageing. Sleep, sedentary behaviour, and virtual reality may be emerging research trends and may predict directions for future research. Collectively, this bibliometric analysis provides a one-step overview of the knowledge structure in this field for researchers and other stakeholders, as well as a reference for future research.

Physical Activity Inclusion in Dementia-Friendly Communities: A Mixed Methods Study

Dementia-friendly communities (DFCs) are a policy-endorsed approach to community engagement in England that promotes social inclusion to enable people affected by dementia to live well. Research suggests that physical activity is beneficial in encouraging social connection and improving health. A mixed method sequential study design in England involving a national survey (n = 31) and semistructured interviews (n = 65) in three DFCs was carried out. The aim was to understand how DFCs enable people affected by dementia to participate in physical activities. An evaluation framework for DFCs was used to organize and interpret the data, and analysis was informed by the inclusive (social) citizen lens. Findings showed that DFCs offered a range of adapted dementia-inclusive and dementia-specific activities; however, people were not routinely offered information at time of diagnosis. Local authorities (councils) were key to enable access to information and infrastructure change to support sustainable inclusion within their local community.

Sports and Immunity, from the recreational to the elite athlete

The pivotal role of the immune system in physical activity is well-established. While interactions are complex, they tend to constitute discrete immune responses. Moderate intensity exercise causes leukocytosis with a mild anti-inflammatory cytokine profile and immunoenhancement. Above a threshold of intensity, lactate-mediated IL-6 release causes a proinflammatory state followed by a depressed inflammatory state, which stimulates immune adaptation and longer term cardiometabolic enhancement. Exercise-related immune responses are modulated by sex, age and immunonutrition. At all ability levels, these factors collectively affect the immune balance between enhancement or overload and dysfunction. Excessive training, mental stress or insufficient recovery risks immune cell exhaustion and hypothalamic pituitary axis (HPA) stress responses causing immunodepression with negative impacts on performance or general health. Participation in sport provides additional immune benefits in terms of ensuring regularity, social inclusion, mental well-being and healthier life choices in terms of diet and reduced smoking and alcohol, thereby consolidating healthy lifestyles and longer term health. Significant differences exist between recreational and professional athletes in terms of inherent characteristics, training resilience and additional stresses arising from competition schedules, travel-related infections and stress. Exercise immunology examines the central role of immunity in exercise physiology and straddles multiple disciplines ranging from neuroendocrinology to nutrition and genetics, with the aim of guiding athletes to train optimally and safely. This review provides a brief outline of the main interactions of immunity and exercise, some influencing factors, and current guidance on maintaining immune health.

Alzheimer's disease prevention: Apolipoprotein e4 moderates the effect of physical activity on brain beta-amyloid deposition in healthy older adults

OBJECTIVES

To investigate if higher baseline physical activity levels are associated with less β-amyloid burden and whether the ApoE4 genotype moderates this association cross-sectionally and longitudinally.

DESIGN

Prospective cohort study.

METHODS

204 cognitively normal older adults (74.5 ± 6.6 years; 26 % ApoE4-carrier) were analyzed. Baseline physical activity was measured using the Minnesota Physical Activity Questionnaire. Brain β-amyloid burden was measured with positron emission tomography using 11C-labeled Pittsburgh compound. A subsample of 128 participants underwent longitudinal positron emission tomography (2.0 ± 0.9 scans over 5 ± 3 years). Statistical analysis was run according to physical activity (high/low group) and the ApoE4 genotype (carrier/noncarrier).

RESULTS

The ApoE4 genotype moderated the relationship between physical activity and β-amyloid, such that low physical activity had a greater impact on β-amyloid deposition in ApoE4-carriers than noncarriers. This ApoE4 × physical activity effect on brain β-amyloid deposition was also observed when all available β-amyloid scan timepoints were included in the model. β-amyloid deposition increased over time (p < 0.001), and ApoE4-carriers had disproportionately greater β-amyloid accumulation than ApoE4-noncarriers. The lower physical activity group had marginally greater β-amyloid accumulation than the higher physical activity group (p = 0.099), but there was no significant ApoE4 effect on β-amyloid accumulation.

CONCLUSIONS

Low physical activity in combination with the ApoE4-carrier genotype is associated with increased β-amyloid burden, suggesting that ApoE4 moderates the effect of physical activity on β-amyloid load. However, this effect was insufficient for baseline physical activity to modulate the change in β-amyloid accumulation over time.

Unveiling the link between physical activity levels and dementia risk: Insights from the UK Biobank study

BACKGROUND

There is limited information on the mixture effect and weights of light physical activity (LPA), moderate physical activity (MPA), and vigorous physical activity (VPA) on dementia risk.

METHODS

A prospective cohort study was conducted based on the UK Biobank dataset. We included participants aged at least 45 years old without dementia at baseline between 2006-2010. The weighted quantile sum regression was used to explore the mixture effect and weights of three types of physical activity on dementia risk.

RESULTS

This study includes 354,123 participants, with a mean baseline age of 58.0-year-old and 52.4 % of female participants. During a median follow-up time of 12.5 years, 5,136 cases of dementia were observed. The mixture effect of LPA, MPA, and VPA on dementia was statistically significant (β: -0.0924, 95 % Confidence Interval (CI): (-0.1402, -0.0446), P < 0.001), with VPA (weight: 0.7922) contributing most to a lower dementia risk, followed by MPA (0.1939). For Alzheimer's disease, MPA contributed the most (0.8555); for vascular dementia, VPA contributed the most (0.6271).

CONCLUSION

For Alzheimer's disease, MPA was identified as the most influential factor, while VPA stood out as the most impactful for vascular dementia.

Physical exercise, cognition, and brain health in aging

Exercise training is an important strategy to counteract cognitive and brain health decline during aging. Evidence from systematic reviews and meta-analyses supports the notion of beneficial effects of exercise in cognitively unimpaired and impaired older individuals. However, the effects are often modest, and likely influenced by moderators such as exercise training parameters, sample characteristics, outcome assessments, and control conditions. Here, we discuss evidence on the impact of exercise on cognitive and brain health outcomes in healthy aging and in individuals with or at risk for cognitive impairment and neurodegeneration. We also review neuroplastic adaptations in response to exercise and their potential neurobiological mechanisms. We conclude by highlighting goals for future studies, including addressing unexplored neurobiological mechanisms and the inclusion of under-represented populations.

Observational evidence of the association between physical and psychological determinants of aging with cognition in older adults

Aging involves physical and cognitive deterioration in older adults. Detecting predictors of dementia early is crucial to identify its onset. This study aimed to associate physical and psychological determinants with cognitive performance in older adults. Observational study with 221 older adults, classified according to cognitive impairment. We evaluated cognitive function by Mini-Mental State Examination. Physical determinants encompassed muscle strength, functional mobility, and cardiorespiratory fitness, while psychological consisted of quality of life and activities of daily living. Multiple linear regression was performed to investigate this relationship. Physical and psychological determinants were significantly linked to cognitive impairment, including lower muscle strength, reduced functional mobility and of cardiorespiratory fitness. The influence of environment, autonomy, and engagement in daily activities on cognitive impairment was also observed. The analysis of physical and psychological determinants could help to aid in distinguishing individuals with cognitive impairment.

The impact of physical exercise on hippocampal atrophy in mild cognitive impairment and Alzheimer's disease: a meta-analysis

Physical activity (PA) is a promising therapeutic for Alzheimer's disease (AD). Only a handful of meta-analyses have studied the impact of PA interventions on regional brain volumes, and none to date has solely included studies on effect of PA on regional brain volumes in individuals with cognitive impairment (CI). In this meta-analysis, we examined whether there is support for the hypothesis that PA interventions positively impact hippocampal volume (HV) in individuals with CI. We also assessed whether the level of CI [mild CI (MCI) vs. AD] impacted this relationship. We identified six controlled trials that met inclusion criteria. These included 236 participants with AD, MCI, or preclinical AD. Data were extracted and analyzed following Cochrane guidelines. We used a random-effects model to estimate the mean change in HV pre- and post-exercise intervention. Forest plots, Hedges' g funnel plots, and Egger's test were used to assess unbiasedness and visualize intervention effects, and Tau 2 , Cochran's Q, and I 2 were calculated to assess heterogeneity. The primary analysis revealed a significant positive effect of PA on total HV. However, sub-group analyses indicated a significant preservation of HV only in individuals with MCI, but not in those with AD. Egger's test indicated no evidence of publication bias. Subgroup analyses also revealed significant heterogeneity only within the MCI cohort for the total and left HV. PA demonstrated a moderate, significant effect in preserving HV among individuals with MCI, but not AD, highlighting a therapeutic benefit, particularly in earlier disease stages.

Design and Rationale of a Two-Armed Randomized Controlled Trial on Yoga/Brisk Walking-Based Lifestyle Modification on Dementia Risk Reduction, and Influence of ApoE Genotypes on the Intervention

Background/Introduction

Though considered a late-onset disease, the 2020 report of the Lancet Commission emphasizes the necessity of conducting primary prevention trials with an approach of never too early in the life course for dementia prevention. Driven by the same notion, we hereby aim to compare the dementia risk reduction potential of two potential interventions, 48 weeks (12 months) of yoga and brisk walking, in middle-aged high-risk subjects.

Design

A randomized controlled trial.

Setting

Community in India.

Participants

In total, 323 at-risk dementia subjects will be recruited from community settings through health awareness camps and door-to-door surveys across Delhi, India. Participants will be randomized into yoga or brisk-walking groups (1:1). The yoga intervention group will receive 60 contact yoga sessions per 60-min/day at the community parks, followed by continued tele-supervised home practice, further followed by at-home self-practice, and will be tested at 3-time points (baseline, 24-week and 48-week, post-randomization) to test the efficacy of the intervention. The control group will be asked to do brisk walking daily for 45 minutes at their convenience, followed by weekly telephone follow-ups. Applying the intention-to-treat principle, the primary endpoint will be the change from baseline at the 12th month in the Cardiovascular Risk Factors, Aging, and Dementia (CAIDE) Scores. Secondary outcomes will include the composite scores derived from a comprehensive neuropsychology battery, comprising the Trail Making Test, Digit Span Test, N Back, Color Trail, Animal Fluency Test, COWA (Controlled Oral Word Association Test), and Digit Symbol Substitution. The primary outcome will be analyzed using mixed-effect models for repeated measures, adjusted for covariates as fixed effects. The study has been prospectively registered (CTRI/2023/02/049746) on February 15, 2023. The protocol was conceptualized in 2021 and approved by the Institutional Ethics Committee of SVYASA. Recruitment began in February 2023 and is underway with patient enrollment.

Conclusion

To our knowledge, this is the first controlled trial to investigate the longitudinal effects of a yoga-based intervention on dementia risk reduction using the CAIDE risk score. The findings of this trial will also provide insight into a better understanding of genotype-dependent responses to yoga intervention and open up avenues for understanding the implications of gene-intervention interactions for precision prevention using yoga.

Association between household size and risk of incident dementia in the UK Biobank study

Currently, the relationship between household size and incident dementia, along with the underlying neurobiological mechanisms, remains unclear. This prospective cohort study was based on UK Biobank participants aged ≥ 50 years without a history of dementia. The linear and non-linear longitudinal association was assessed using Cox proportional hazards regression and restricted cubic spline models. Additionally, the potential mechanisms driven by brain structures were investigated by linear regression models. We included 275,629 participants (mean age at baseline 60.45 years [SD 5.39]). Over a mean follow-up of 9.5 years, 6031 individuals developed all-cause dementia. Multivariable analyses revealed that smaller household size was associated with an increased risk of all-cause dementia (HR, 1.06; 95% CI 1.02-1.09), vascular dementia (HR, 1.08; 95% CI 1.01-1.15), and non-Alzheimer's disease non-vascular dementia (HR, 1.09; 95% CI 1.03-1.14). No significant association was observed for Alzheimer's disease. Restricted cubic splines demonstrated a reversed J-shaped relationship between household size and all-cause and cause-specific dementia. Additionally, substantial associations existed between household size and brain structures. Our findings suggest that small household size is a risk factor for dementia. Additionally, brain structural differences related to household size support these associations. Household size may thus be a potential modifiable risk factor for dementia.

Systematic review and meta-analysis of randomized controlled trials on the effects of exercise interventions on amyloid beta levels in humans

Alzheimer's disease (AD) represents the most common type of dementia. A crucial mechanism attributed to its development is amyloid beta (Aβ) dynamics dysregulation. The extent to which exercise can modulate this phenomenon is uncertain. The aim of this study was to summarize the existing literature evaluating this issue. A comprehensive systematic search was performed in Pubmed, Scopus, Embase, Web of Science, and SciELO databases and completed in August 2023, aiming to identify randomized controlled trials investigating the effect of exercise upon Aβ-related pathology. The keywords "exercise" and "amyloid beta", as well as all their equivalents and similar terms, were used. For the analysis, the negative or positive dementia status of the subjects was initially considered and then the soluble amyloid precursor protein (sAPP) components and Aβ fragments separately. A meta-analysis was performed and involved eight studies (moderate-to-high quality) and 644 assessments, which were 297 for control and 347 for exercise. No overall effect favoring exercise interventions was observed for both negative (SMD95%=0,286 [-0,131; 0,704]; p = 0,179) or positive AD dementia status (SMD95%=0,110 [-0,155; 0,375]; p = 0,416). The absence of an overall effect favoring exercise interventions was also found for Aβ peptides (SMD95%=0,226 [-0,028; 0,480]; p = 0,081) and for sAPP components (SMD95%=-0,038 50 [-0,472; 0,396]; p = 0,863) levels. Our findings suggest that exercise interventions do not improve Aβ-related pathology in both healthy individuals and individuals with dementia (SMD95%=0,157 [-0,059; 0,373]; p = 0,155), indicating that the beneficial effects of exercise for AD reported in previous studies are related to other mechanistic effects rather than direct amyloid effects (PROSPERO registration number: CRD42023426912).

A Two-Phased Pilot Study Evaluating the Feasibility and Acceptability of the Cognitively Enriched Walking Program "Take a Walk with Your Brain" for Older Adults

Given the aging population, finding solutions to retain optimal cognitive capacity is a research priority. The potential of physical activity to reduce the risk of cognitive decline and to enhance cognitive functioning is established. Combining physical with cognitive activity has been put forward as a potentially even more effective way to promote healthy cognitive aging. Most studies on combined interventions have however been conducted in laboratory settings. This paper reports on a two-phased pilot study evaluating the acceptability and feasibility of a newly developed real-life cognitively enriched walking program for adults aged 65+ years. In Phase I, the feasibility and enjoyability of the cognitive tasks was evaluated by conducting walk-along interviews with older adults (n = 163). In Phase II, the cognitively enriched walking program was piloted in two groups of older adults (n = 19), and the feasibility and acceptability of the program and cognitive tasks was evaluated by means of questionnaires and focus groups. The cognitive tasks (i.e., median scores of ≥3 on a total of 4 (Phase I) and ≥6 on a total of 10 (Phase II) for most of the tasks) and the cognitively enriched walking program (i.e., median scores of ≥7 on a total of 10) were considered feasible and acceptable. Based on the input of the participants, key considerations for a feasible and acceptable program were defined: participants should be sufficiently challenged cognitively and physically, social interaction is an important motivator, cognitive tasks should make use of stimuli reflecting daily life and be conducted in group, the rationale for the tasks should be explained to participants, the frequency of the group sessions should be maximum 2 times a week, and the program should be supervised by a trained coach. These results warrant future research to establish the effectiveness of this program.

The impact of exercise on Alzheimer's disease progression

INTRODUCTION

The preventive effects of chronic physical exercise (CPE) on Alzheimer's disease (AD) are now admitted by the scientific community. Curative effects of CPE are more disputed, but they deserve to be investigated, since CPE is a natural non-pharmacological alternative for the treatment of AD.

AREAS COVERED

In this perspective, the authors discuss the impact of CPE on AD based on an exhaustive literature search using the electronic databases PubMed, ScienceDirect and Google Scholar.

EXPERT OPINION

Aerobic exercise alone is probably not the unique solution and needs to be complemented by other exercises (physical activities) to optimize the slowing down of AD. Anaerobic, muscle strength and power, balance/coordination and meditative exercises may also help to slow down the AD progression. However, the scientific evidence does not allow a precise description of the best training program for patients with AD. Influential environmental conditions (e.g. social relations, outdoor or indoor exercise) should also be studied to optimize training programs aimed at slowing down the AD progression.

Changes in EEG Activity and Cognition Related to Physical Activity in Older Adults: A Systematic Review

Aging is generally associated with a decline in important cognitive functions that can be observed in EEG. Physical activity in older adults should be considered one of the main strategies to promote health and prevent disease in the elderly. The present study aimed to systematically review studies of EEG activity and cognitive function changes associated with physical activity in older adults. Records from PubMed, Scopus, and EBSCO databases were searched and, following the PRISMA guidelines, nine studies were included in the present systematic review. A risk of bias assessment was performed using the National Institute of Health Quality Assessment Tool for Case-control Studies instrument. The studies analyzed used two main strategies to determine the effects of physical activity on cognition and EEG: (1) multiscale entropy and power frequencies; and (2) event-related potentials. In terms of EEG activity, it can be concluded that exercise-induced neuroplasticity underlies improvements in cognitive function in healthy older adults.

Leisure-Time Physical Activity May Attenuate the Impact of Diabetes on Cognitive Decline in Middle-Aged and Older Adults: Findings From the ELSA-Brasil Study

OBJECTIVE

To assess leisure-time physical activity (LTPA) as a modifier of the diabetes/cognitive decline association in middle-aged and older participants in the Estudo Longitudinal de Saude do Adulto (ELSA-Brasil) study.

RESEARCH DESIGN AND METHODS

ELSA-Brasil is a cohort of 15,105 participants (age 35-74 years) enrolled between 2008 and 2010. We evaluated global cognitive function, summing the scores of six standardized tests evaluating memory and verbal fluency, including the Trail-Making Test, at baseline and follow-up. Incident cognitive impairment was defined as a global cognitive function score at follow-up lower than -1 SD from baseline mean. Participants reporting ≥150 min/week of moderate to vigorous LTPA at baseline were classified as physically active. We assessed the association of LTPA with global cognition change in those with diabetes in the context of our overall sample through multivariable regression models.

RESULTS

Participants' (N = 12,214) mean age at baseline was 51.4 (SD 8.8) years, and 55.5% were women. During a mean follow-up of 8.1 (SD 0.6) years, 9,345 (76.5%) inactive participants and 1,731 (14.1%) participants with diabetes at baseline experienced faster declines in global cognition than those who were active (β = -0.003, -0.004, and -0.002) and those without diabetes (β = -0.004, -0.005, and -0.003), respectively. Diabetes increased the risk of cognitive impairment (hazard ratio [HR] 1.71; 95% Cl 1.22, 2.39) in inactive but not in active adults (HR 1.18; 95% CI 0.73, 1.90). Among participants with diabetes, those who were active showed a delay of 2.73 (95% CI 0.94, 4.51) years in the onset of cognitive impairment.

CONCLUSIONS

In adults living with diabetes, LTPA attenuated the deleterious association between diabetes and cognitive function.

Lifetime Physical Activity and Late-Life Mild Cognitive Impairment in Community-Dwelling Older Adults

OBJECTIVES

Regular physical activity throughout life is generally recommended to prevent dementia; however, there is little evidence regarding the association between lifetime physical activity and mild cognitive impairment (MCI), which often precedes dementia. This study aimed to examine the association of lifetime physical activity and their transitions with late-life MCI.

DESIGN

A population-based case-control study.

SETTING AND PARTICIPANTS

A total of 2968 Japanese community-dwelling older adults aged ≥70 years without dementia.

METHODS

We evaluated the participants' early-, mid-, and late-life physical activity habits and categorized their transitions across life stages. Cognitive functions in late life were assessed for memory, attention, executive function, and processing speed; functional impairment in one or more cognitive domains was defined as MCI.

RESULTS

Regular physical activity in early life was not significantly associated with late-life MCI [odds ratio (OR), 0.80; 95% CI, 0.63-1.02], although those in mid-life (OR, 0.64; 95% CI, 0.51-0.81) and late-life (OR, 0.74; 95% CI, 0.59-0.91) were associated with lower odds of late-life MCI. Compared with nonexercisers, participants who acquired new habits of physical activity during mid- or late-life (OR, 0.71; 95% CI, 0.55-0.91) and those who maintained physical activity throughout their life span (OR, 0.61; 95% CI, 0.42-0.87) had lower odds of late-life MCI; those who stopped regular activity during mid- or late-life did not (OR, 0.79; 95% CI, 0.58-1.06).

CONCLUSIONS AND IMPLICATIONS

While physical activity throughout the life span is associated with the lowest odds of MCI, starting regular physical activity, even later in life, confers a benefit and should be encouraged as a "lifelong approach" to MCI risk reduction.

A Dual-Task Paradigm Combining Physical and Cognitive Training in Mice: Application to Aging

Physical Activity (PA) is often associated with better overall health status, especially in older adults. Numerous pieces of evidence indicate that PA would be more beneficial when applied in conjunction with Cognitive Training (CT) either simultaneously (i.e., in Dual-Task [DT]) or sequentially. Nonetheless, the underlying mechanisms of such benefits remain elusive. To help delve deeper into their understanding, we developed a cognitive-motor DT paradigm in young adult mice and subsequently tested its effect in old age. Three groups of young adults C57BL/6J mice (3.5 months of age; n=10/group) were required. They were given cognitive tasks, either alone (Control) or in combination with PA which was administered either sequentially (SeqT group) or simultaneously (DT group). Mice were trained in a touchscreen chamber: first on a Visual Discrimination (VD) learning task, then on its Reversal (RVD) which assesses cognitive flexibility alongside procedural learning. PA was given through a homemade treadmill, designed to fit in the touchscreen chambers and set at 9 m/min. Fourteen months later, we further evaluated the effects of PA administered in both DT and SeqT groups, on the performance of the now 19-month-old mice. When compared to SeqT and control groups, DT mice significantly displayed better procedural learning in both VD and RVD tasks as young adults. In the RVD task, this enhanced performance was associated with both poorer inhibition and motor performance. Finally, in 19-month-old mice, both DT and SeqT mice displayed better motor and cognitive performances than control mice. This new cognitive-motor DT paradigm in mice yields an interesting framework that should be useful for adapting DT training in aging, including providing knowledge on the neurobiological correlates, to get the most out of its benefits.

Physical Activity and Cognitive Decline Among Older Adults: A Systematic Review and Meta-Analysis

Importance

Physical activity is associated with the risk for cognitive decline, but much of the evidence in this domain comes from studies with short follow-ups, which is prone to reverse causation bias.

Objective

To examine how length of follow-up, baseline age, physical activity amount, and study quality modify the longitudinal associations of physical activity with cognition.

Data Sources

Observational studies of adults with a prospective follow-up of at least 1 year, a valid baseline cognitive measure or midlife cohort, and an estimate of the association of baseline physical activity and follow-up cognition were sought from PsycInfo, Scopus, CINAHL, Web of Science, SPORTDiscus, and PubMed, with the final search conducted on November 2, 2022.

Study Selection

Two independent researchers screened titles with abstracts and full-text reports.

Data Extraction and Synthesis

Two reviewers independently assessed study quality and extracted data. Pooled estimates of association were calculated with random-effects meta-analyses. An extensive set of moderators, funnel plots, and scatter plots of physical activity amount were examined. This study is reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guideline.

Main Outcomes and Measures

Pooled estimates of the associations between physical activity and global cognition, as well as specific cognitive domains, were examined.

Results

A total of 104 studies with 341 471 participants were assessed. Analysis of binary outcomes included 45 studies with 102 452 individuals, analysis of follow-up global cognition included 14 studies with 41 045 individuals, and analysis of change in global cognition included 25 studies with 67 463 individuals. Physical activity was associated with a decreased incidence of cognitive impairment or decline after correction for funnel plot asymmetry (pooled risk ratio, 0.97; 95% CI, 0.97-0.99), but there was no significant association in follow-ups longer than 10 years. Physical activity was associated with follow-up global cognition (standardized regression coefficient, 0.03; 95% CI, 0.02-0.03) and change in global cognition (standardized regression coefficient, 0.01; 95% CI, 0.01 to 0.02) from trim-and-fill analyses, with no clear dose-response or moderation by follow-up length, baseline age, study quality or adjustment for baseline cognition. The specific cognitive domains associated with physical activity were episodic memory (standardized regression coefficient, 0.03; 95% CI, 0.02-0.04) and verbal fluency (standardized regression coefficient, 0.05; 95% CI, 0.03-0.08).

Conclusions and Relevance

In this meta-analysis of the association of physical activity with cognitive decline, physical activity was associated with better late-life cognition, but the association was weak. However, even a weak association is important from a population health perspective.