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

Association of hypoglycemic events with cognitive impairment in patients with type 2 diabetes mellitus: Protocol for a dose-response meta-analysis

INTRODUCTION

With an incidence rate as high as 46%-58%, hypoglycemia is a common complication of glycemic management among those suffering from type 2 diabetes mellitus(T2DM). According to preclinical research, hypoglycemia episodes may impair cognition by harming neurons. However, there is still controversy regarding the clinical evidence for the relationship between hypoglycemic events and the likelihood of cognitive impairment. Furthermore, little research has been done on the dose-response association between hypoglycemia incidents and the possibility of cognitive impairment. To address these knowledge gaps, the present research intends to update the comprehension of the association among hypoglycemic events and the risk of cognitive impairment and to clarify the correlation between dose and response by incorporating the most recent investigations.

METHOD AND ANALYSIS

This work has developed a protocol for a systematic review and meta-analysis that will examine, via a well-organized assessment of several databases, the relationship between the incidence of hypoglycemia and the probability of cognitive impairment. Observational studies investigating the connection between hypoglycemia episodes and cognitive impairment will be included. The databases that will be searched are PubMed, Web of Science, the Chinese Biomedical Literature Database (CBM), Cochrane Library, Embase, the China National Knowledge (CNKI), Wan Fang, the Chinese Science and Technology Periodical Database (VIP), and Du Xiu. Literature from the establishment of each database to December 2023 will be included in the search. Two researchers will independently screen the studies that satisfy the requirements for both inclusion and exclusion. A third researcher will be asked to mediate any disputes. The methodological caliber of the studies included will be assessed utilizing the Newcastle-Ottawa Scale (NOS) or the Joanna Briggs Institute (JBI) critical appraisal method. With regard to GRADE, which stands for Grading of Recommendations, Assessment, Development, and Evaluation, the quality of the evidence will be evaluated. ROBIS Tool will be used to evaluate the risk of bias in the development of the systematic review. If the data is accessible, meta-analysis and dose-response curve analysis will be employed by Stata software. However, if the data does not allow for such analysis, a descriptive review will be performed.

DISCUSSION AND CONCLUSION

Hypoglycemic episodes may raise the likelihood of cognitive impairment, according to earlier investigations. This study will update the relevant evidence and explore the dose-response connection between hypoglycemic episodes and cognitive impairment. The results of this review will have significant effects on decision-making by individuals with diabetes, healthcare providers, and government policy institutions.

TRIAL REGISTRATION

Prospero registration number: CRD42023432352.

Association of step counts with cognitive function in apparently healthy middle-aged and older Japanese men

Background

Increasing physical activity may prevent cognitive decline. Previous studies primarily focused on older adults and used self-reported questionnaires to assess physical activity. We examined the relationship between step count, an objective measure of physical activity, and cognitive function in community-based middle-aged and older Japanese men.

Methods

The Shiga Epidemiological Study of Subclinical Atherosclerosis randomly recruited community-dwelling healthy men aged 40-79 years from Shiga, Japan, and measured their step counts over 7 consecutive days using a pedometer at baseline (2006-2008). Among men who returned for follow-up (2009-2014), we assessed their cognitive function using the Cognitive Abilities Screening Instrument (CASI) score. We restricted our analyses to those with valid 7-day average step counts at baseline and those who remained free of stroke at follow-up (n = 676). Using analysis of covariance, we calculated the adjusted means of the CASI score according to the quartiles of the average step counts.

Results

The mean (standard deviation) of age and unadjusted CASI score were 63.8 (9.1) years and 90.8 (5.8), respectively. The CASI score was elevated in higher quartiles of step counts (90.2, 90.4, 90.6, and 91.8 from the lowest to the highest quartile, respectively, [p for trend = 0.004]) in a model adjusted for age and education. Further adjustment for smoking, drinking, and other cardiovascular risk factors resulted in a similar pattern of association (p for trend = 0.005).

Conclusion

In apparently healthy middle-aged and older Japanese men, a greater 7-day average step count at baseline was associated with significantly higher cognitive function score.

Social Isolation, Physical Activity, and Subsequent Changes in Cognition Among Middle- and Older-Aged Adults: Results From the Canadian Longitudinal Study on Aging

OBJECTIVE

The objectives of this study were to a) evaluate associations between social isolation and change in cognition over a 3-year period, and b) evaluate whether physical activity mediates the association between social isolation and cognition change.

METHODS

Using baseline and follow-up 1 data from the Canadian Longitudinal Study on Aging, latent change score models, incorporating direct and indirect pathways, were constructed to estimate the indirect effect of social isolation on cognitive change through physical activity. Multigroup models were constructed based on age group (45-65 versus 65+ years) and sex to allow for varying estimates across age and sex. The final analytic sample included 51,338 participants.

RESULTS

Indirect effects of social isolation on cognition through physical activity were evident in men and women 65+ years old for memory change ( = -0.005 [99.9% confidence interval = -0.007 to -0.002], p < .001 in both groups) and in male adults 65+ years old for executive function change ( = -0.01 [99.9% confidence interval = -0.02 to -0.006], p < .001). Statistically significant indirect effects were not observed for adults between 45 and 65 years old.

CONCLUSIONS

Social isolation is associated with diminished physical activity, and in turn, diminished physical activity is associated with decline in memory in older women and men, with larger declines in executive function in older men. Public health initiatives to promote physical activity-perhaps incorporating social interaction-among older adults experiencing social isolation could be one way to mitigate the negative impact of social isolation on cognitive health.

The impact of modifiable health metrics on mortality for older adults with low cognitive function

Objectives

Cognitive impairment has emerged as a major contributing factor to mortality for older adults. Identifying the strong modifiable health metrics against mortality is of high priority, especially in this high-risk population.

Methods

This population-based study used data of US adults aged≥60 years old from the National Health and Nutrition Examination Survey 2011-2014 cycles. De-identified data for participants who completed cognitive function test were extracted. Mortality data was obtained by linking to the 2019 public-use linked mortality file.

Results

Participants with low global cognition had higher risk of all-cause mortality (HR = 1.46; 95%CI, 1.04-2.05). The highest prevalence of ideal level of health metrics was observed for sleep duration (54.36% vs. 62.37%), and the lowest was noted for blood pressure (12.06% vs. 21.25%) for participants with low and average to high global cognition, respectively. Ideal status of physical activity and diet quality were significantly associated with all-cause mortality among participants with low global cognition (HR = 0.48, 95%CI: 0.28-0.82; HR = 0.63, 95%CI: 0.43-0.95). The corresponding population-attributable fractions were 26.58 and 15.90%, respectively.

Conclusion

Low cognitive function was associated with increased risk of all-cause death for older adults. Attainment of healthy metrics, especially sufficient physical activity, consuming healthy diet and being never smoked, provided strong protection against death risk.

Digital Therapeutics for Improving Effectiveness of Pharmaceutical Drugs and Biological Products: Preclinical and Clinical Studies Supporting Development of Drug + Digital Combination Therapies for Chronic Diseases

Limitations of pharmaceutical drugs and biologics for chronic diseases (e.g., medication non-adherence, adverse effects, toxicity, or inadequate efficacy) can be mitigated by mobile medical apps, known as digital therapeutics (DTx). Authorization of adjunct DTx by the US Food and Drug Administration and draft guidelines on "prescription drug use-related software" illustrate opportunities to create drug + digital combination therapies, ultimately leading towards drug-device combination products (DTx has a status of medical devices). Digital interventions (mobile, web-based, virtual reality, and video game applications) demonstrate clinically meaningful benefits for people living with Alzheimer's disease, dementia, rheumatoid arthritis, cancer, chronic pain, epilepsy, depression, and anxiety. In the respective animal disease models, preclinical studies on environmental enrichment and other non-pharmacological modalities (physical activity, social interactions, learning, and music) as surrogates for DTx "active ingredients" also show improved outcomes. In this narrative review, we discuss how drug + digital combination therapies can impact translational research, drug discovery and development, generic drug repurposing, and gene therapies. Market-driven incentives to create drug-device combination products are illustrated by Humira® (adalimumab) facing a "patent-cliff" competition with cheaper and more effective biosimilars seamlessly integrated with DTx. In conclusion, pharma and biotech companies, patients, and healthcare professionals will benefit from accelerating integration of digital interventions with pharmacotherapies.

Current perspectives on prevention of vascular cognitive impairment and promotion of vascular brain health

INTRODUCTION

The true global burden of vascular cognitive impairment (VCI) is unknown. Reducing risk factors for stroke and cardiovascular disease would inevitably curtail VCI.

AREAS COVERED

The authors review current diagnosis, epidemiology, and risk factors for VCI. VCI increases in older age and by inheritance of known genetic traits. They emphasize modifiable risk factors identified by the 2020 Lancet Dementia Commission. The most profound risks for VCI also include lower education, cardiometabolic factors, and compromised cognitive reserve. Finally, they discuss pharmacological and non-pharmacological interventions.

EXPERT OPINION

By virtue of the high frequencies of stroke and cardiovascular disease the global prevalence of VCI is expectedly higher than prevalent neurodegenerative disorders causing dementia. Since ~ 90% of the global burden of stroke can be attributed to modifiable risk factors, a formidable opportunity arises to reduce the burden of not only stroke but VCI outcomes including progression from mild to the major in form of vascular dementia. Strict control of vascular risk factors and secondary prevention of cerebrovascular disease via pharmacological interventions will impact on burden of VCI. Non-pharmacological measures by adopting healthy diets and encouraging physical and cognitive activities and urging multidomain approaches are important for prevention of VCI and preservation of vascular brain health.

Exercise-Related Physical Activity Relates to Brain Volumes in 10,125 Individuals

BACKGROUND

The potential neuroprotective effects of regular physical activity on brain structure are unclear, despite links between activity and reduced dementia risk.

OBJECTIVE

To investigate the relationships between regular moderate to vigorous physical activity and quantified brain volumes on magnetic resonance neuroimaging.

METHODS

A total of 10,125 healthy participants underwent whole-body MRI scans, with brain sequences including isotropic MP-RAGE. Three deep learning models analyzed axial, sagittal, and coronal views from the scans. Moderate to vigorous physical activity, defined by activities increasing respiration and pulse rate for at least 10 continuous minutes, was modeled with brain volumes via partial correlations. Analyses adjusted for age, sex, and total intracranial volume, and a 5% Benjamini-Hochberg False Discovery Rate addressed multiple comparisons.

RESULTS

Participant average age was 52.98±13.04 years (range 18-97) and 52.3% were biologically male. Of these, 7,606 (75.1%) reported engaging in moderate or vigorous physical activity approximately 4.05±3.43 days per week. Those with vigorous activity were slightly younger (p < 0.00001), and fewer women compared to men engaged in such activities (p = 3.76e-15). Adjusting for age, sex, body mass index, and multiple comparisons, increased days of moderate to vigorous activity correlated with larger normalized brain volumes in multiple regions including: total gray matter (Partial R = 0.05, p = 1.22e-7), white matter (Partial R = 0.06, p = 9.34e-11), hippocampus (Partial R = 0.05, p = 5.96e-7), and frontal, parietal, and occipital lobes (Partial R = 0.04, p≤1.06e-5).

CONCLUSIONS

Exercise-related physical activity is associated with increased brain volumes, indicating potential neuroprotective effects.

Physical Activity in Mild Vascular Cognitive Impairment: Results of the AFIVASC Randomized Controlled Trial at 6 Months

Background

Vascular cognitive impairment is frequent, in mild (mVCI) or severe forms (vascular dementia).

Objective

To do a randomized controlled-trial to evaluate the impact of physical activity on cognition (primary outcome), neurocognitive measures, quality of life, functional status, and physical function (secondary outcomes), in patients with mVCI.

Methods

A hundred and four patients with mVCI (mean age 71.2 years; 53 women) were randomized for a six-month intervention of moderate physical activity (60-minute sessions, 3 times/week) (n = 53) or best-practice "usual care" (n = 51). Comprehensive evaluations of primary and secondary outcomes included an objective measure of physical activity through accelerometry at baseline and after intervention.

Results

Mean session attendance was 58%. Adverse events were negligible. After 6 months, no significant primary outcome change was observed, either in the intervention or 'usual care' group. The intervention group improved significantly in some secondary outcomes in physical function - aerobic capacity (U = 403; p = 0.000) and agility (U = 453; p = 0.005) after 6 months. Regardless of randomization arm, a post-hoc analysis based on fulfilling at least 21.5 minutes/day of moderate or 10.7 minutes/day of vigorous physical activity (World Health Organization-WHO standards) revealed improvements. These were not only in motor capacity but also on the global measure of cognition, executive functions and memory.

Conclusions

Physical activity was safe and beneficial regarding domains of physical function. No significant cognitive decline was registered over 6-months, regardless of intervention allocation. Larger samples, longer follow-ups and focus on intervention adherence are needed to fully analyze the impact of WHO recommendations for physical activity in mVCI populations.

Biomarker Responses to Acute Exercise and Relationship with Brain Blood Flow

BACKGROUND

There is evidence that aerobic exercise is beneficial for brain health, but these effects are variable between individuals and the underlying mechanisms that modulate these benefits remain unclear.

OBJECTIVE

We sought to characterize the acute physiological response of bioenergetic and neurotrophic blood biomarkers to exercise in cognitively healthy older adults, as well as relationships with brain blood flow.

METHODS

We measured exercise-induced changes in lactate, which has been linked to brain blood flow, as well brain-derived neurotrophic factor (BDNF), a neurotrophin related to brain health. We further quantified changes in brain blood flow using arterial spin labeling.

RESULTS

As expected, lactate and BDNF both changed with time post exercise. Intriguingly, there was a negative relationship between lactate response (area under the curve) and brain blood flow measured acutely following exercise. Finally, the BDNF response tracked strongly with change in platelet activation, providing evidence that platelet activation is an important mechanism for trophic-related exercise responses.

CONCLUSIONS

Lactate and BDNF respond acutely to exercise, and the lactate response tracks with changes in brain blood flow. Further investigation into how these factors relate to brain health-related outcomes in exercise trials is warranted.

Harnessing Passive Pulsatile Shear Stress for Alzheimer's Disease Prevention and Intervention

Alzheimer's disease (AD) affects more than 40 million people worldwide and is the leading cause of dementia. This disease is a challenge for both patients and caregivers and puts a significant strain on the global healthcare system. To address this issue, the Lancet Commission recommends focusing on reducing modifiable lifestyle risk factors such as hypertension, diabetes, and physical inactivity. Passive pulsatile shear stress (PPSS) interventions, which use devices like whole-body periodic acceleration, periodic acceleration along the Z-axis (pGz), and the Jogging Device, have shown significant systemic and cellular effects in preclinical and clinical models which address these modifiable risks factors. Based on this, we propose that PPSS could be a potential non-pharmacological and non-invasive preventive or therapeutic strategy for AD. We perform a comprehensive review of the biological basis based on all publications of PPSS using these devices and demonstrate their effects on the various aspects of AD. We draw from this comprehensive analysis to support our hypothesis. We then delve into the possible application of PPSS as an innovative intervention. We discuss how PPSS holds promise in ameliorating hypertension and diabetes while mitigating physical inactivity, potentially offering a holistic approach to AD prevention and management.

Attitudes and Considerations for Multidomain Lifestyle Approaches to Dementia Prevention: A Qualitative Study

BACKGROUND

Dementia, with the most common form being Alzheimer's disease, is a global health issue and lifestyle-based strategies may reduce risk. Individuals with a family history of dementia are an important target group, but little is known about their attitudes and perceptions of dementia risk reduction.

OBJECTIVE

To elucidate the attitudes to and key considerations for multidomain lifestyle-based dementia prevention strategies in middle-aged Australians with a family history of dementia.

METHODS

Twenty participants (80% female; age range 47-65 years), undertook semi-structured phone-based interviews. Inductive thematic analysis of interview transcripts was conducted. Hierarchical coding frames and illustrative quotes were compiled and critically challenged until a final set of themes was produced.

RESULTS

Some participants expressed a positive attitude toward lifestyle-based dementia prevention. Reasons related to wanting to future proof, believing that risk reduction is relevant at all life stages and/or that there is always room for improvement. Other participants had a negative attitude, expressing that they were already following a healthy lifestyle, did not feel it was relevant to them yet, and/or held a deterministic view that dementia is random. Important considerations congregated on the themes of being tailored/personalized, taking a holistic approach, and involving small, achievable steps.

CONCLUSIONS

In individuals with a family history of dementia, a positive attitude to dementia prevention holds promise for intervention efforts, but in individuals expressing negative attitudes, further education and individual-level counselling may be warranted. Multidomain lifestyle-based preventive strategies also need to be tailored to the needs of key target groups to optimize appeal and effectiveness.

Dose-response associations, physical activity intensity and mortality risk: A narrative review

Physical activity is consistently associated with reduced mortality, decreased risk for non-communicable diseases, and improved mental health in observational studies. Randomized controlled trials and observational Mendelian randomization studies support causal links between physical activity and health outcomes. However, the scarcity of evidence from randomized controlled trials, along with their inherent challenges like exposure contrasts, healthy volunteer biases, loss to follow-up, and limited real-world dose-response data, warrants a comprehensive approach. This review advocates synthesizing insights from diverse study designs to better understand the causal relationship between physical activity, mortality risk, and other health outcomes. Additionally, it summarizes recent research since the publication of current physical activity recommendations. Novel observational studies utilizing device-measured physical activity underscore the importance of every minute of activity and suggest that all intensity levels confer health benefits, with vigorous-intensity potentially requiring lower volumes for substantial benefits. Future guidelines, informed by device-measured physical activity studies, may offer refined age-specific recommendations, emphasize vigorous-intensity physical activity, and include daily step counts as a simple, easily assessable metric using commercial wearables.

The Potential of a Stratified Approach to Drug Repurposing in Alzheimer's Disease

Alzheimer's disease (AD) is a complex neurodegenerative condition that is characterized by the build-up of amyloid-beta plaques and neurofibrillary tangles. While multiple theories explaining the aetiology of the disease have been suggested, the underlying cause of the disease is still unknown. Despite this, several modifiable and non-modifiable factors that increase the risk of developing AD have been identified. To date, only eight AD drugs have ever gained regulatory approval, including six symptomatic and two disease-modifying drugs. However, not all are available in all countries and high costs associated with new disease-modifying biologics prevent large proportions of the patient population from accessing them. With the current patient population expected to triple by 2050, it is imperative that new, effective, and affordable drugs become available to patients. Traditional drug development strategies have a 99% failure rate in AD, which is far higher than in other disease areas. Even when a drug does reach the market, additional barriers such as high cost and lack of accessibility prevent patients from benefiting from them. In this review, we discuss how a stratified medicine drug repurposing approach may address some of the limitations and barriers that traditional strategies face in relation to drug development in AD. We believe that novel, stratified drug repurposing studies may expedite the discovery of alternative, effective, and more affordable treatment options for a rapidly expanding patient population in comparison with traditional drug development methods.

Impact of type, intensity, frequency, duration and volume of physical activity on dementia and mild cognitive impairment in older adults: protocol for a systematic review and meta-analysis

INTRODUCTION

Worldwide, the prevalence of degenerative diseases such as dementia and mild cognitive impairment (MCI) is increasing with population ageing and increasing life expectancy. Both conditions share modifiable risk factors. Physical inactivity is one of these modifiable risk factors, and research points to the protective effect of physical activity on the incidence of dementia and MCI. However, this association tends to change according to type, intensity, frequency, duration and volume of physical activity. Furthermore, it remains unclear which of these characteristics offers the greatest protective effect. Therefore, this study aims to evaluate the impacts of different types, intensities, frequencies, duration and volume of physical activity on dementia and cognitive decline in older adults.

METHODS AND ANALYSIS

The search will be carried out from October 2023, using the following databases: PubMed, Embase, Scopus, CINAHL and Web of Science. Cohort studies with a follow-up time of 1 year or longer that have investigated the incidence of dementia and/or MCI in older adults exposed to physical activity will be included. There will be no limitations on the date of publication of the studies. Studies published in English, Spanish or Portuguese will be analysed. Two researchers will independently screen the articles and extract the data. Any discrepancies will be resolved by a third reviewer. Association measures will be quantified, including OR, HR, relative risk and incidence ratio, with a 95% CI. If the data allow, a meta-analysis will be performed. To assess the methodological quality of the selected studies, the Grading of Recommendations, Assessment, Development and Evaluations instrument, and the Downs and Black instrument to assess the risk of bias, will be used.

ETHICS AND DISSEMINATION

Ethical approval is not required. The results will be submitted for publication in a peer-reviewed journal.

PROSPERO REGISTRATION NUMBER

CRD42023400411.

Associations between physical inactivity and dementia prevalence: ecological study using global data

OBJECTIVES

Given the predicted rise in dementia prevalence around the world, targeting modifiable risk factors (often lifestyle related) is a priority. This work sought to understand the role of physical inactivity (PI) as a modifiable risk factor for dementia.

STUDY DESIGN

Ecological study using globally available ecological data (both 2010 and 2016) from 192 countries.

METHODS

Age-standardised PI prevalence and dementia prevalence data were accessed from the World Health Organisation (WHO) and the Global Burden of Disease Study. Linear regression was used to assess the relationship between PI and dementia, with stratified analyses used to further explore the impact of sex, WHO region, and World Bank income group on the relationship.

RESULTS

Linear regression showed a positive association between inactivity and dementia prevalence in 2010 (b = 1.38 [95% confidence interval {CI}: 0.04, 2.71] P = 0.044) and 2016 (coefficient = 2.52 [95% CI: 1.07, 3.96] P = 0.0007). Sub-group analyses of sex-specific data showed the strength of the relationship was stronger in men than in women. Rates of both dementia and inactivity rose with increasing world income group.

CONCLUSIONS

This analysis of global data indicates the presence of a positive relationship between prevalence of PI and dementia prevalence, which has increased in strength with time, and is stronger in men than in women. This highlights the importance of public health interventions on a global scale to reduce the percentage of the population failing to reach or exceed the recommended physical activity guidelines.

Moderate and vigorous leisure time physical activity in older adults and Alzheimer's disease-related mortality in the USA: a dose-response, population-based study

BACKGROUND

Data for the dose-response associations of moderate physical activity (MPA) and vigorous physical activity (VPA) with Alzheimer's disease-related mortality are scarce. We aimed to examine the prospective associations of such activity with Alzheimer's disease-related mortality.

METHODS

In this dose-response, population-based study, we pooled data from 22 consecutive waves of the US National Health Interview Survey (from 1997 to 2018). Participants aged 68 years or older were included in the study if they had full data for physical or muscle-strengthening activity, chronic conditions, functional limitations, marital status, education level, alcohol consumption, smoking status, and BMI, and follow-up time after study entry. Participants were linked to the National Death Index until Dec 31, 2019. We defined Alzheimer's disease-related mortality as a leading cause by using the G-30 code of the International Statistical Classification of Diseases and Related Health Problems tenth revision. Information on MPA and VPA was self-reported, with participants asked to answer four questions on the frequency and duration of both types of physical activity. We calculated hazard ratios (HRs) and used restricted cubic splines models to assess dose-response associations, and we estimated the annual number of Alzheimer's disease-related deaths that could be prevented through physical activity using adjusted population attributable fractions.

FINDINGS

After excluding 21 377 participants, 91 298 adults were included in the analysis. The weighted mean participant age was 75·8 years (SE 0·0); 55 658 (56·7%) were female and 76 796 (87·6%) were White (weighted percentages). The median follow-up was 6·5 years (IQR 3·6-10·7), corresponding to 703 393 person-years. 2176 (2·4%) participants died due to Alzheimer's disease as the leading cause. For MPA, we did not find a significant dose-response association with Alzheimer's disease-related mortality, whereas for VPA, we observed a significant L-shaped association between 20 weekly min and 190 weekly min. For VPA, we identified a minimal amount (ie, 50% of the optimal amount) at 40 min/week (HR 0·91, 95% CI 0·84-0·95) and an optimal amount (ie, the nadir of the curve) at 140 min/week (0·79, 0·66-0·95) for reducing Alzheimer's disease-related mortality. For the USA, we estimated that 40 weekly min of VPA would prevent 12 238 deaths per year (95% CI 89-23 172) and 140 weekly min of VPA would prevent 37 710 deaths per year (311-63 567), compared with a scenario in which US adults did not do any VPA.

INTERPRETATION

These findings might inform future guidelines for preventing Alzheimer's disease-related mortality by emphasising the importance of VPA over MPA and providing specific VPA targets.

FUNDING

None.

Association between perceived risk of Alzheimer's disease and related dementias and cognitive function among U.S. older adults

INTRODUCTION

The aim of the study was to assess factors associated with the perceived risk of developing Alzheimer's disease and related dementias (ADRD) and how the perceived risk of ADRD was related to cognitive function.

METHODS

We conducted a retrospective cohort study using 5 waves of data from the Health and Retirement Study (2012-2022) that included adults aged 65 years or older with no previous diagnosis of ADRD at baseline. Cognitive function was measured at baseline and over time using a summary score that included immediate/delayed word recall, serial 7's test, objective naming test, backwards counting, recall of the current date, and naming the president/vice-president (range = 0-35). Perceived risk of developing ADRD was categorized at baseline as "definitely not" (0% probability), "unlikely" (1-49%), "uncertain" (50%), and "more than likely" (>50-100%). Additional baseline measures included participants' sociodemographic background, psychosocial resources, health behaviors, physiological status, and healthcare utilization.

RESULTS

Of 1457 respondents (median age 74 [IQR = 69-80] and 59.8% women), individuals who perceived that they were "more than likely" to develop ADRD had more depressive symptoms and were more likely to be hospitalized in the past two years than individuals who indicated that it was "unlikely" they would develop ADRD. Alternatively, respondnets who perceived that they would "definitely not" develop ADRD were more likely to be non-Hispanic Black, less educated, and have lower income than individuals who indicated it was "unlikely" they would develop ADRD. Respondents who reported their risks of developing ADRD as "more than likely" (β = -2.10, P < 0.001) and "definitely not" (β = -1.50, P < 0.001) had the lowest levels of cognitive function; and the associations were explained in part by their socioeconomic, psychosocial, and health status.

CONCLUSIONS

Perceived risk of developing ADRD is associated with cognitive function. The (dis)concordance between individuals' perceived risk of ADRD and their cognitive function has important implications for increasing public awareness and developing interventions to prevent ADRD.

White matter abnormalities mediate the association between masticatory dysfunction and cognition among older adults

BACKGROUND

Masticatory parameters, such as reduced number of teeth and posterior contacts, have been shown to be associated with reduced cognitive status. The underlying mechanisms that affect these associations, are however, not well understood.

OBJECTIVES

The study aims to investigate the association between masticatory dysfunction and cognition and explore the mediating effect of brain structure.

METHODS

In this cross-sectional study, 45 older adults with subjective masticatory dysfunction (mean age 72.3 ± 4.0 years) were included. Mini-Mental State Examination score <25, brain trauma, neurological disease, neurodegenerative disorders, depression or poor Swedish language skills were criteria for exclusion. Cognitive functions (executive function and episodic memory) and masticatory dysfunction defined by functional occluding status (FOS; the number of occluding units and number of remaining teeth) were analysed with partial correlation models. Structural magnetic resonance imaging was performed on 28 feasible participants. Multiple regression analyses were performed to evaluate the predictive value of brain structure and white matter hypointensities (WM-hypo) on cognitive functions. A mediation analysis was applied to assess significant predictor/s of the association between FOS and cognition.

RESULTS

Both episodic memory and executive functions were positively correlated with FOS. WM-hypo predicted cognitive status (executive function, p ≤ .01). WM-hypo mediated 66.6% (p = 0.06) of the association between FOS and executive functions.

CONCLUSION

Associations between FOS and cognitive functions are reported, where FOS, a potential modifiable risk factor, was related to both episodic memory and executive functions. The mediating effect of WM-hypo on the association between FOS and executive functions highlights the impact of the vascularisation of the brain on the link between mastication and cognition. The present study provides increased knowledge that bridges the gap between masticatory dysfunction and cognition.

Gut-muscle-brain axis: Molecular mechanisms in neurodegenerative disorders and potential therapeutic efficacy of probiotic supplementation coupled with exercise

Increased longevity is often associated with age-related conditions. The most common neurodegenerative disorders in the older population are Alzheimer's disease (AD) and Parkinson's disease (PD), associated with progressive neuronal loss leading to functional and cognitive impairments. Although symptomatic treatments are available, there is currently no cure for these conditions. Gut dysbiosis has been involved in the pathogenesis of AD and PD, thus interventions targeting the "gut-brain axis" could potentially prevent or delay these pathologies. Recent evidence suggests that the skeletal muscle and the gut microbiota can affect each other via the "gut-muscle axis". Importantly, cognitive functions in AD and PD patients significantly benefit from physical activity. In this review, we aim to provide a comprehensive picture of the crosstalk between the brain, the skeletal muscle and the gut microbiota, introducing the concept of "gut-muscle-brain axis". Moreover, we discuss human and animal studies exploring the modulatory role of exercise and probiotics on cognition in AD and PD. Collectively, the findings presented here support the potential benefits of physical activity and probiotic supplementation in AD and PD. Further studies will be needed to develop targeted and multimodal strategies, including lifestyle changes, to prevent or delay the course of these pathologies.

Effect of physical activity on risk of Alzheimer's disease: A systematic review and meta-analysis of twenty-nine prospective cohort studies

OBJECTIVE

Physical activity (PA) is beneficial in reductions of all-cause mortality and dementia. However, whether Alzheimer's disease (AD) risk is modified by PA remains disputable. This meta-analysis aims to disclose the underlying relationship between PA and incident AD.

METHODS

Pubmed, Embase, Cochrane Library, and Web of Science were retrieved from inception to June 2023. Random-effects models were employed to derive the effect size, represented by hazard ratio (HR) and 95% confidence interval (CI).

RESULTS

Twenty-nine prospective cohort studies involving 2068,519 participants were included. The pooled estimate showed a favorable effect of PA on AD risk decline (HR 0.72, 95% CI 0.65-0.80). This association remained robust after adjusting for maximum confounders (HR 0.85, 95% CI 0.79-0.91). Subgroup analysis of PA intensity demonstrated an inverse dose-response relationship between PA and AD, effect sizes of which were significant in moderate (HR 0.85, 95% CI 0.80-0.93) and high PA (HR 0.56, 95% CI 0.45-0.68), but not in low PA (HR 0.94, 95% CI 0.77-1.15). Regardless of all participants or the mid-life cohort, the protection of PA against AD appeared to be valid in shorter follow-up (<15 years) rather than longer follow-up (≥15 years). In addition to follow-up, the robustness of the estimates persisted in supplementary meta-analyses, meta-regression analyses, and sensitivity analyses.

CONCLUSION

PA intervention reduces the incidence of AD, but merely in moderate to vigorous PA with follow-up of less than 15 years, thus conditionally recommending the popularization of PA as a modifiable lifestyle factor to prevent AD.

The comprehensive mechanism underlying Schisandra polysaccharide in AD-like symptoms of Aβ25-35-induced rats based on hippocampal metabolomics and serum lipidomics techniques

As is well documented, Alzheimer's disease (AD) is the most prevalent neurodegenerative disease. Meanwhile, Schisandra polysaccharide (SCP) has been reported to exert a protective effect on the nervous system and can regulate metabolic disorders in AD-like symptoms of amyloid β-peptide (Aβ) 25-35-induced rats. Nevertheless, the underlying mechanisms and metabolic markers for the diagnosis of AD are yet to be determined. This study aimed to explore the neuroprotective effect and potential mechanism of action of SCP in AD-like symptoms of Aβ25-35-induced rats by combining pharmacodynamics, metabolomics, and lipidomics. The pharmacodynamic results revealed that SCP significantly improved the spatial learning and long-term memory function and the morphology of neurons in the hippocampal CA1 region, alleviated inflammatory damage and oxidative stress, inhibited the activation of microglia and astrocytes, and increased the proportion of mature neurons of AD-like symptoms of Aβ25-35-induced rats. The results of hippocampal metabolomics and serum lipidomics showed 46 and 48 potential biomarkers were identified for the SCP treatment of AD, respectively. The involved pathways principally comprised lipid metabolism, amino acid metabolism, and energy metabolism. This study elucidates the neuroprotective effect of SCP in AD and its mechanism from the perspective of metabolomics and lipidomics and provides a theoretical basis for the therapeutic effect of SCP in AD.

Exercise Intervention for Alzheimer's Disease: Unraveling Neurobiological Mechanisms and Assessing Effects

Alzheimer's disease (AD) is a progressive neurodegenerative disease and a major cause of age-related dementia, characterized by cognitive dysfunction and memory impairment. The underlying causes include the accumulation of beta-amyloid protein (Aβ) in the brain, abnormal phosphorylation, and aggregation of tau protein within nerve cells, as well as neuronal damage and death. Currently, there is no cure for AD with drug therapy. Non-pharmacological interventions such as exercise have been widely used to treat AD, but the specific molecular and biological mechanisms are not well understood. In this narrative review, we integrate the biology of AD and summarize the knowledge of the molecular, neural, and physiological mechanisms underlying exercise-induced improvements in AD progression. We discuss various exercise interventions used in AD and show that exercise directly or indirectly affects the brain by regulating crosstalk mechanisms between peripheral organs and the brain, including "bone-brain crosstalk", "muscle-brain crosstalk", and "gut-brain crosstalk". We also summarize the potential role of artificial intelligence and neuroimaging technologies in exercise interventions for AD. We emphasize that moderate-intensity, regular, long-term exercise may improve the progression of Alzheimer's disease through various molecular and biological pathways, with multimodal exercise providing greater benefits. Through in-depth exploration of the molecular and biological mechanisms and effects of exercise interventions in improving AD progression, this review aims to contribute to the existing knowledge base and provide insights into new therapeutic strategies for managing AD.

Peripheral inflammation and neurocognitive impairment: correlations, underlying mechanisms, and therapeutic implications

Cognitive impairments, such as learning and memory deficits, may occur in susceptible populations including the elderly and patients who are chronically ill or have experienced stressful events, including surgery, infection, and trauma. Accumulating lines of evidence suggested that peripheral inflammation featured by the recruitment of peripheral immune cells and the release of pro-inflammatory cytokines may be activated during aging and these conditions, participating in peripheral immune system-brain communication. Lots of progress has been achieved in deciphering the core bridging mechanism connecting peripheral inflammation and cognitive impairments, which may be helpful in developing early diagnosis, prognosis evaluation, and prevention methods based on peripheral blood circulation system sampling and intervention. In this review, we summarized the evolving evidence on the prevalence of peripheral inflammation-associated neurocognitive impairments and discussed the research advances in the underlying mechanisms. We also highlighted the prevention and treatment strategies against peripheral inflammation-associated cognitive dysfunction.

Association of accelerometer-measured physical activity intensity, sedentary time, and exercise time with incident Parkinson's disease

Evidence regarding the association between physical activity and Parkinson's disease (PD) risk is generally limited due to the use of self-report questionnaires. We aimed to quantify the separate and combined effects of accelerometer-measured light physical activity (LPA), moderate-to-vigorous physical activity (MVPA), sedentary time and exercise timing with incident PD. 96,422 participants without prior PD and with usable accelerometer data were included from UK Biobank. Time spent in sedentary activity, LPA, MVPA, and exercise timing were estimated using machine learning models. The study outcome was incident PD. Over a median follow-up duration of 6.8 years, 313 participants developed PD. There was a L-shaped association for LPA and MVPA, and a reversed L-shaped association for sedentary time, with the risk of incident PD (all P for nonlinearity < 0.001). Similar trends were found across three time-windows (morning, midday-afternoon, and evening). Compared with those with both low LPA (<3.89 h/day) and low MVPA (<0.27 h/day), the adjusted HR (95% CI) of PD risk was 0.49 (0.36-0.66), 0.19 (0.36-0.66) and 0.13 (0.09-0.18), respectively, for participants with high MVPA only, high LPA only, and both high LPA and high MVPA. Moreover, participants with both low LPA and high sedentary time (≥9.41 h/day) (adjusted HR, 5.59; 95% CI: 4.10-7.61), and those with both low MVPA and high sedentary time (adjusted HR, 3.93; 95% CI: 2.82-5.49) had the highest risk of incident PD. In conclusion, regardless of exercise timing (morning, midday-afternoon, and evening), there was an inverse association for accelerometer-measured MVPA and LPA, and a positive association for sedentary time, with incident PD.

The contribution of being physically active to successful aging

Growing old involves changes in physical, psychological, and cognitive functions. Promoting physical and mental health has become one of the priorities for an aging population. Studies have demonstrated the benefits of engaging in regular physical activity. Here, we aimed to understand the relationships between physical activity and working memory complaints in attention, memory storage, and executive functions. We hypothesized that physical activity was negatively associated with complaints in working memory domains after controlling for socio-demographics and distress factors, such as anxiety, stress, and depression. Two hundred and twenty-three individuals aged between 65 and 100 years (74.84; SD = 7.74; 133 males) without self-reported neurological and/or psychiatric disorders completed a questionnaire on socio-demographic, with questions on physical activity and the Italian version of the working memory questionnaire (WMQ) and the DASS-21 measuring anxiety, stress, and depression. Results from three linear regression models showed that low physical activity was associated with complaints in attention (R2 = 0.35) and executive functions (R2 = 0.37) but not in memory storage (R2 = 0.28). Notably, age, gender, and total emotional distress (DASS score) were significant in all regression models. Our results suggested regular physical activity, even just walking, is crucial for maintaining efficient cognitive function. Theoretical and practical implications for engaging in physical activity programs and social aggregation during exercise are considered. Limitations are also presented.

Change in physical activity and systolic blood pressure trajectories throughout mid-life and the development of dementia in older age: the HUNT study

BACKGROUND

There is lack of research on combinations of possible modifiable risk factors for dementia in a life-time perspective. Dementia has currently no cure, and therefore new knowledge of preventive factors is important. The purpose of this study is to investigate if changes in physical activity (PA) in combinations with systolic blood pressure (SBP) trajectories in mid to late life are related to development of dementia in older age.

METHODS

This prospective cohort study uses data from four consecutive surveys of the HUNT Study, Norway. Dementia was assessed in the HUNT4 70 + sub-study (2017-19). Group-based trajectory modelling identified three SBP trajectories from HUNT1 (1984-86) to HUNT3 (2006-2008): low, middle, and high. Change in PA was categorized into four groups based on high or low PA level at HUNT1 and HUNT3 and were combined with the SBP trajectories resulting in 12 distinct categories. Logistic regression was used to estimate odds ratios (ORs) of dementia.

RESULTS

A total of 8487 participants (55% women, mean age (SD) 44.8 (6.5) years at HUNT1) were included. At HUNT4 70 + , 15.2% had dementia. We observed an overall decrease in OR of dementia across the PA/SBP categories when ranked from low to high PA (OR, 0.96; 95% CI, 0.93 to 1.00, P = 0.04). Within PA groups, a low SBP trajectory was associated with lower OR for dementia, apart from those with decreasing PA. The strongest association was observed for people with stable high PA and low SBP trajectory (OR, 0.38; 95% confidence interval (CI), 0.13 to 1.10 and adjusted risk difference, -8.34 percentage points; 95% CI, -15.32 to -1.36).

CONCLUSION

Our findings illustrate the clinical importance of PA and SBP for dementia prevention and that favorable levels of both are associated with reduced occurrence of dementia.

Handgrip strength, physical activity and incident mild cognitive impairment and dementia

OBJECTIVE

We analyzed the mediating role of handgrip strength in the association between moderate to vigorous physical activity and incident mild cognitive impairment and dementia.

METHODS

We used prospective data from 14 European countries participating in the Survey of Health, Ageing, and Retirement in Europe. 19,686 participants free of dementia and mild cognitive impairment (64.9 ± 8.7 years) were followed up for a mean of 10.2 years. Moderate to vigorous physical activity was self-reported, and handgrip strength was assessed with a dynamometer. Mild cognitive impairment was defined as 1.5 standard deviations below the mean of the standardized global cognition score, while dementia was determined by physician diagnosis. Gender, age, country, education, presence of chronic diseases, depressive symptoms, limitations in activities of daily living, body mass index, and baseline cognitive levels were used as covariates. Cox proportional hazards as well as mediation models were used.

RESULTS

Moderate to vigorous physical activity for at least 1 day per week was independently associated with lower incident mild cognitive impairment (HR: 0.85; 95%CI: 0.74-0.98). A 10 % increase in handgrip strength was associated a 6 % lower hazard for incident mild cognitive impairment (0.94; 0.92-0.97) and 5 % lower hazard for incident dementia (0.95; 0.93-0.98). Handgrip strength partly mediated the association of moderate to vigorous physical activity with mild cognitive impairment (Coefficient: 0.03; 95%CI: 0.01-0.05; 17.9 %).

CONCLUSIONS

Physical activity is independently associated with a lower incidence of mild cognitive impairment.

Systematic review and meta-analysis on population attributable fraction for physical inactivity to dementia

INTRODUCTION

The number of cases of dementia attributable to physical inactivity remains unclear due to heterogeneity in physical inactivity definitions and statistical approaches used.

METHODS

Studies that used population-based samples to estimate the population attributable fraction (PAF) of physical inactivity for dementia were included in this review. Weighted PAFs were adjusted for communality among the risk factors (i.e., inactive persons may also share other risk factors) analyzed. Values were reported as percentage (%) of cases of dementia attributable to physical inactivity.

RESULTS

We included 22 studies. The overall impact of physical inactivity, defined by any criteria, on dementia ranged from 6.6% (95% CI: 3.6%, 9.6%; weighted) to 16.6% (95% CI: 14.4%, 18.9%; unweighted). Studies using the WHO criterion for physical inactivity estimated a higher unweighted impact (β = 7.3%; 95% CI: 2.0%, 12.6%) than studies using other criteria.

DISCUSSION

Conservatively, one in 15 cases of dementia may be attributable to physical inactivity, defined by any criteria.

Physical activity and exercise for the prevention and management of mild cognitive impairment and dementia: a collaborative international guideline

BACKGROUND

Physical activity and exercise have been suggested as effective interventions for the prevention and management of mild cognitive impairment (MCI) and dementia, but there are no international guidelines.

OBJECTIVES

To create a set of evidence- and expert consensus-based prevention and management recommendations regarding physical activity (any bodily movement produced by skeletal muscles that results in energy expenditure) and exercise (a subset of physical activity that is planned, structured, repetitive), applicable to a range of individuals from healthy older adults to those with MCI/dementia.

METHODS

Guideline content was developed with input from several scientific and lay representatives' societies. A systematic search across multidisciplinary databases was carried out until October 2021. Recommendations for prevention and management were developed according to the GRADE and complemented by consensus statements from the expert panels.

RECOMMENDATIONS

Physical activity may be considered for the primary prevention of dementia. In people with MCI there is continued uncertainty about the role of physical activity in slowing the conversion to dementia. Mind-body interventions have the greatest supporting evidence. In people with moderate dementia, exercise may be used for maintaining disability and cognition. All these recommendations were based on a very low/low certainty of evidence.

CONCLUSIONS

Although the scientific evidence on the beneficial role of physical activity and exercise in preserving cognitive functions in subjects with normal cognition, MCI or dementia is inconclusive, this panel, composed of scientific societies and other stakeholders, recommends their implementation based on their beneficial effects on almost all facets of health.

Noradrenergic neuromodulation in ageing and disease

The locus coeruleus (LC) is a small brainstem structure located in the lower pons and is the main source of noradrenaline (NA) in the brain. Via its phasic and tonic firing, it modulates cognition and autonomic functions and is involved in the brain's immune response. The extent of degeneration to the LC in healthy ageing remains unclear, however, noradrenergic dysfunction may contribute to the pathogenesis of Alzheimer's (AD) and Parkinson's disease (PD). Despite their differences in progression at later disease stages, the early involvement of the LC may lead to comparable behavioural symptoms such as preclinical sleep problems and neuropsychiatric symptoms as a result of AD and PD pathology. In this review, we draw attention to the mechanisms that underlie LC degeneration in ageing, AD and PD. We aim to motivate future research to investigate how early degeneration of the noradrenergic system may play a pivotal role in the pathogenesis of AD and PD which may also be relevant to other neurodegenerative diseases.

Association between physical activity and body posture: a systematic review and meta-analysis

OBJECTIVE

To estimate the possible associations between posture and physical activity (PA).

DESIGN

A systematic review and meta-analysis.

DATA SOURCES

The search was conducted in seven databases (PubMed, Web of Science, SportDiscus, EMBASE, Scopus, Cochrane Library, and CINAHL) for studies published from inception to January 2023.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies were required to meet following criteria: (1) study design: cross-sectional, case control and cohort studies. (2) Participants: people of all ages without any diagnosed diseases. (3) Exposure and outcome: studies that examined the possible effect or correlations between PA, physical inactivity, physical exertion and human body posture.

RESULTS

Sixteen cross-sectional studies, two cohort studies and one case control study involving a total of 16772 participants aged from 6 to 79 years were included. Correlational studies showed that there was a significant relationship between PA and posture (C = 0.100, CI 95% = 0.012-0.186). However, regression studies demonstrated that there was not a significant association between PA and posture (C = 1.00, CI 95% = 0.998-1.002). Three studies investigated the association between PA and the lumbar lordosis and showed that there was not a significant association between the lordosis and PA (CI 95%: -0.253-0.048, P = 0.180). In addition, four studies showed that there were not any associations between scoliosis and PA (CI 95%: 0.819, 1.123, P = 0.607). The evidence of heterogeneity and publication bias was found among all analyzed data (P < 0.05). Also, meta regression was used for age and BMI and the results were not significant.

CONCLUSION

Although a weak correlation was shown to exist between PA and human posture, the odds ratio indicated that there was not a significant association between PA and human posture. The lack of a significant relationship may indicate that multiple biopsychosocial factors may be involved in human posture. In summary, our study highlights the need for caution when interpreting the results of meta-analyses, particularly when there is significant heterogeneity and publication bias in the included studies.

The embodied mind in motion: a neuroscientific and philosophical perspective on prevention and therapy of dementia

The embodied mind in motion is a concept in which health and well-being, prevention and therapy, as well as lifestyle and habits meet. The mind changes profoundly in the course of dementias, affecting daily living and resulting in reduced quality of life. Interdisciplinary approaches are required for a holistic understanding of how the mind is affected by dementia. We here explore what such a holistic theory of dementia might look like and propose the idea of "embodied mind in motion". The paradigm is biopsychosocial or biocultural, the theoretical anchor point is the lifeworld, and the guiding concept is "embodiment," as body and mind are constantly in motion. Physical activity is, hence, central for the experience of health and well-being, beyond being "exercise" and "health behavior". We discuss the embodied mind in motion referring to phenomenology, enactivism and (philosophical) anthropology. In our view, habits are embodied long-term memories and a philosophical equivalent to lifestyle. They unfold the meaningfulness of moving the body, complementing the objectifiable benefits of physical exercise. Empirical studies on "holistic activities" like hiking, yoga, music and dance illustrate improved integration into everyday life. Their meaningfulness enhances compliance and increases the preventive and even therapeutic potential. A crucial factor for this is the emotional dimension of lifestyle, exemplified by the virally popularized performance of "Swan Lake" by wheel-chair bound ex-ballerina Marta Cinta González Saldaña, suffering from Alzheimer's disease. A number of epistemological and ontological consequences anchor "embodied movement" as a valuable principle for dementia research.

Underlying Mechanisms of Brain Aging and Neurodegenerative Diseases as Potential Targets for Preventive or Therapeutic Strategies Using Phytochemicals

During aging, several tissues and biological systems undergo a progressive decline in function, leading to age-associated diseases such as neurodegenerative, inflammatory, metabolic, and cardiovascular diseases and cancer. In this review, we focus on the molecular underpinning of senescence and neurodegeneration related to age-associated brain diseases, in particular, Alzheimer's and Parkinson's diseases, along with introducing nutrients or phytochemicals that modulate age-associated molecular dysfunctions, potentially offering preventive or therapeutic benefits. Based on current knowledge, the dysregulation of microglia genes and neuroinflammation, telomere attrition, neuronal stem cell degradation, vascular system dysfunction, reactive oxygen species, loss of chromosome X inactivation in females, and gut microbiome dysbiosis have been seen to play pivotal roles in neurodegeneration in an interactive manner. There are several phytochemicals (e.g., curcumin, EGCG, fucoidan, galangin, astin C, apigenin, resveratrol, phytic acid, acacetin, daucosterol, silibinin, sulforaphane, withaferin A, and betulinic acid) that modulate the dysfunction of one or several key genes (e.g., TREM2, C3, C3aR1, TNFA, NF-kb, TGFB1&2, SIRT1&6, HMGB1, and STING) affected in the aged brain. Although phytochemicals have shown promise in slowing down the progression of age-related brain diseases, more studies to identify their efficacy, alone or in combinations, in preclinical systems can help to design novel nutritional strategies for the management of neurodegenerative diseases in humans.

Does Therapeutic Exercise Support Improvement in Cognitive Function and Instrumental Activities of Daily Living in Patients with Mild Alzheimer's Disease? A Randomized Controlled Trial

This randomized controlled trial aims to investigate the effect of 12 weeks of therapeutic exercise on cognitive function and daily activities in patients with mild Alzheimer's disease (AD). A total of 171 patients with mild AD from the Amarousion Day Care Center of the Alzheimer Society of Athens and the Athens General Hospital "G. Gennimatas" were randomly divided into three groups. Group A (aerobic and resistance exercise, n = 57), group B (resistance exercise, n = 57), and group C (control group, n = 57). Group A followed a weekly program consisting of 5 days with 30 min walking and 3 days with resistance exercises for about 45 min. Group B followed only a resistance exercise program, the same as group A. Group C did not participate in any exercise program. After the intervention, cognitive function was assessed with the Cognitive Examination-Revised (ACE-R), Trail Making Test A-B (TMT A-B), and Digit Span Test Forward and Backward (DST F-B) and daily activities with the instrumental activities of daily living scale (IADLs). A significant intervention effect was observed for all outcome measures (global cognitive function and instrumental activities of daily living). ANCOVA Bonferroni corrected post hoc tests revealed that the aerobic and resistance group improved compared to the control group on all measurement scales. The resistance group also showed an improvement compared to the control group. No significant effects were found between the aerobic and resistance group and the resistance group in any of the outcome measures.

Modifiable cardiovascular risk factors and genetics for targeted prevention of dementia

Dementia is a major global challenge for health and social care in the 21st century. A third of individuals >65 years of age die with dementia, and worldwide incidence numbers are projected to be higher than 150 million by 2050. Dementia is, however, not an inevitable consequence of old age; 40% of dementia may theoretically be preventable. Alzheimer's disease (AD) accounts for approximately two-thirds of dementia cases and the major pathological hallmark of AD is accumulation of amyloid-β. Nevertheless, the exact pathological mechanisms of AD remain unknown. Cardiovascular disease and dementia share several risk factors and dementia often coexists with cerebrovascular disease. In a public health perspective, prevention is crucial, and it is suggested that a 10% reduction in prevalence of cardiovascular risk factors could prevent more than nine million dementia cases worldwide by 2050. Yet this assumes causality between cardiovascular risk factors and dementia and adherence to the interventions over decades for a large number of individuals. Using genome-wide association studies, the entire genome can be scanned for disease/trait associated loci in a hypothesis-free manner, and the compiled genetic information is not only useful for pinpointing novel pathogenic pathways but also for risk assessments. This enables identification of individuals at high risk, who likely will benefit the most from a targeted intervention. Further optimization of the risk stratification can be done by adding cardiovascular risk factors. Additional studies are, however, highly needed to elucidate dementia pathogenesis and potential shared causal risk factors between cardiovascular disease and dementia.

Physical activity, sedentary behavior and pancreatitis risk: Mendelian randomization study

BACKGROUND

Although observational studies have shown that physical activity is a protective factor for acute pancreatitis, the causal associations between PA/ sedentary behavior and acute pancreatitis (AP) and chronic pancreatitis (CP) remain unclear.

METHODS

We used Mendelian randomization as a strategy to assess the causalities between exposures and outcomes by simulating randomized experiments with genetic variation. The collected genetic variants data of physical activity were from UK Biobank, the data on sedentary behavior were also from UK Biobank, and both of them could be found in the GWAS catalog, and the data on AP and CP were from FinnGen. There were three physical activity related activity patterns (moderate to vigorous physical activity [MVPA], accelerometer-based physical activity with average acceleration, [AccAve] and accelerometer-based physical activity with accelerations >425 milli-gravities, [Acc425]) and three sedentary behavior-related lifestyle patterns (Leisure screen time [LST], Sedentary commuting, Sedentary behavior at work). We used inverse variance weighted (IVW), weighted median and MR-Egger for the analysis of Mendelian randomization, followed by sensitivity tests with the Cochran Q test, MR-Egger intercepts analysis and MR-PRESSO.

RESULTS

A causal relationship was found between LST and acute pancreatitis based on IVW analysis (odds ratios [OR] = 1.38, corresponding 95% confidence intervals [CI] = 1.16-1.64, p = 0.0002) and there were no causal relationships between physical activity/sedentary behavior and chronic pancreatitis. Sensitivity analysis showed no pleiotropy and heterogeneity of the results.

CONCLUSIONS

Results show that reducing LST contributes to the prevention of acute pancreatitis, thereby reducing the health burden associated with it.

Exercise interveNtion outdoor proJect in the cOmmunitY - results from the ENJOY program for independence in dementia: a feasibility pilot randomised controlled trial

The Seniors Exercise Park program is an evidence-based outdoor physical and social activity program designed originally for older people with no cognitive impairment. This study aimed to pilot this program for people living with dementia in residential aged care. We examined the feasibility of delivering the program, evaluating its structure, safety, and supervision needs. In addition, physical, social, health and cognitive benefits of participation were examined. Method This was a feasibility pilot randomised controlled design. Adults aged ≥ 60 years with symptoms of dementia and/or diagnoses of dementia were recruited from an aged care facility in Australia. Participants allocated to the intervention underwent a 12-week structured supervised physical activity program using the outdoor Seniors Exercise Park equipment followed by a 12-week maintenance phase, while the controls received usual care programs. Assessments occurred at baseline, 12 and 24-weeks. Feasibility evaluation included recruitment rate, retention, attendance, overall adherence, dropout rate, adverse events, program delivery modifications and supervision requirements. A suite of cognitive and health-related questionnaires and physical function measures were also collected. Results Sixteen participants were recruited (recruitment rate: 58.6%), eight for the intervention (83.3 ± 7.5 years, 87.5% women) and eight for the control (age 87.5 ± 3.0 years, 87.5% women). Eighty-eight percent completed the 12-week structured program, with 75% retention at 24-weeks. Across the 24-week period, 84.3% participation adherence was reported. No falls or adverse events occurred. Modifications of the program mainly related to method of communication, cueing and adjustments to suit individual personality and characteristics. A ratio of one trainer to two participants was practical and safe. There were no significant changes over time between groups in any of the secondary outcomes. High level of engagement, enjoyment and mood was reported throughout the exercise program. Conclusion The Seniors Exercise Park physical activity program was safe and feasible for people living with dementia in residential care, with high levels of enjoyment, positive attitude, and engagement reported in the intervention group. Individualised communication during program delivery was needed to facilitate motivation and participation. Further research is needed to assess the program effectiveness on physical and cognitive function on a larger scale. Trial registration This trial is registered with the Australian New Zealand Clinical Trials Registry-Registry Number ACTRN12620000733976 . Registered on the 13/07/2020.

Association between physical activity and episodic memory and the moderating effects of the apolipoprotein E ε4 allele and age

Background

An abundance of evidence indicates that physical activity may protect against Alzheimer's disease (AD) and related cognitive decline. However, little is known about the association between physical activity and AD-related cognitive decline according to age and the apolipoprotein E (APOE) ε4 allele (APOE4) as major risk factors. Therefore, we examined whether age and APOE4 status modulate the effects of physical activity on episodic memory as AD-related cognition in non-demented older adults.

Methods

We enrolled 196 adults aged between 65 and 90 years, with no dementia. All participants underwent comprehensive clinical assessments including physical activity evaluation and APOE genotyping. The AD-related cognitive domain was assessed by the episodic memory, as the earliest cognitive change in AD, and non-memory cognition for comparative purposes. Overall cognition was assessed by the total score (TS) of the Consortium to Establish a Registry for Alzheimer's Disease neuropsychological battery.

Results

We found significant physical activity × age and physical activity × APOE4 interaction effects on episodic memory. Subgroup analyses indicated that an association between physical activity and increased episodic memory was apparent only in subjects aged > 70 years, and in APOE4-positive subjects.

Conclusion

Our findings suggest that physical activity has beneficial effects on episodic memory, as an AD-related cognitive domain, in individuals aged > 70 years and in APOE4-positive individuals. Physicians should take age and APOE4 status account into when recommending physical activity to prevent AD-related cognitive decline.

The association between physical activity and cognitive function in the elderly in rural areas of northern China

Background

Physical activity plays an important role in cognitive function in older adults, and the threshold effect and saturation effect between physical activity and cognitive function are unclear.

Objective

The purpose of this study was to explore the threshold effect and saturation effect between physical activity and cognitive function in the elderly.

Methods

The International Physical Activity Questionnaire (IPAQ) was used to measure moderate-intensity physical activity and vigorous-intensity physical activity and total physical activity in older adults. Cognitive function assessment uses the Beijing version of the Montreal Cognitive Assessment Scale (MoCA). The scale consists of seven parts: visual space, naming, attention, language, abstract ability, delayed recall and orientation, for a total of 30 points. The total score of the study participants < 26 was defined as the optimum cutoff point for a definition of mild cognitive impairment (MCI). The multivariable linear regression model was used to initially explore the relationship between physical activity and total cognitive function scores. The logistic regression model was used to assess the relationship between physical activity and cognitive function dimensions and MCI. The threshold effect and saturation effect between the total physical activity and the total cognitive function scores were investigated by smoothed curve fitting.

Results

This cross-sectional survey had a total of 647 participants aged 60 years and older (mean age: 73 years, female: 53.7%). Participants' higher level of physical activity were associated with higher visual space, attention, language, abstract ability, and delayed recall scores (P < 0.05). Physical activity was not statistically associated with naming and orientation. Physical activity was a protective factor for MCI (P < 0.05). Physical activity was positively correlated with total cognitive function scores. There was a saturation effect between total physical activity and total cognitive function scores, and the saturation point was 6546 MET × min/wk.

Conclusion

This study showed a saturation effect between physical activity and cognitive function, and determined an optimal level of physical activity to protect cognitive function. This finding will help update physical activity guidelines based on cognitive function in the elderly.

Precious but convenient means of prevention and treatment: physiological molecular mechanisms of interaction between exercise and motor factors and Alzheimer's disease

Disproportionate to the severity of Alzheimer's disease (AD) and the huge number of patients, the exact treatment and prevention of AD is still being explored. With increasing ageing, the search for means to prevent and treat AD has become a high priority. In the search for AD, it has been suggested that exercise may be one of the more effective and less costly means of preventing and treating AD, and therefore a large part of current research is aimed at exploring the effectiveness of exercise in the prevention and treatment of AD. However, due to the complexity of the specific pathogenesis of AD, there are multiple hypotheses and potential mechanisms for exercise interventions in AD that need to be explored. This review therefore specifically summarises the hypotheses of the interaction between exercise and AD from a molecular perspective, based on the available evidence from animal models or human experiments, and explores them categorised according to the pathologies associated with AD: exercise can activate a number of signalling pathways inhibited by AD (e.g., Wnt and PI3K/Akt signalling pathways) and reactivate the effects of downstream factors regulated by these signalling pathways, thus acting to alleviate autophagic dysfunction, relieve neuroinflammation and mitigate Aβ deposition. In addition, this paper introduces a new approach to regulate the blood-brain barrier, i.e., to restore the stability of the blood-brain barrier, reduce abnormal phosphorylation of tau proteins and reduce neuronal apoptosis. In addition, this paper introduces a new concept." Motor factors" or "Exerkines", which act on AD through autocrine, paracrine or endocrine stimulation in response to movement. In this process, we believe there may be great potential for research in three areas: (1) the alleviation of AD through movement in the brain-gut axis (2) the prevention and treatment of AD by movement combined with polyphenols (3) the continued exploration of movement-mediated activation of the Wnt signalling pathway and AD.

Examining later-in-life health risks associated with sport-related concussion and repetitive head impacts: a systematic review of case-control and cohort studies

OBJECTIVE

Concern exists about possible problems with later-in-life brain health, such as cognitive impairment, mental health problems and neurological diseases, in former athletes. We examined the future risk for adverse health effects associated with sport-related concussion, or exposure to repetitive head impacts, in former athletes.

DESIGN

Systematic review.

DATA SOURCES

Search of MEDLINE, Embase, Cochrane, CINAHL Plus and SPORTDiscus in October 2019 and updated in March 2022.

ELIGIBILITY CRITERIA

Studies measuring future risk (cohort studies) or approximating that risk (case-control studies).

RESULTS

Ten studies of former amateur athletes and 18 studies of former professional athletes were included. No postmortem neuropathology studies or neuroimaging studies met criteria for inclusion. Depression was examined in five studies in former amateur athletes, none identifying an increased risk. Nine studies examined suicidality or suicide as a manner of death, and none found an association with increased risk. Some studies comparing professional athletes with the general population reported associations between sports participation and dementia or amyotrophic lateral sclerosis (ALS) as a cause of death. Most did not control for potential confounding factors (eg, genetic, demographic, health-related or environmental), were ecological in design and had high risk of bias.

CONCLUSION

Evidence does not support an increased risk of mental health or neurological diseases in former amateur athletes with exposure to repetitive head impacts. Some studies in former professional athletes suggest an increased risk of neurological disorders such as ALS and dementia; these findings need to be confirmed in higher quality studies with better control of confounding factors.

PROSPERO REGISTRATION NUMBER

CRD42022159486.

Consensus statement on concussion in sport: the 6th International Conference on Concussion in Sport-Amsterdam, October 2022

For over two decades, the Concussion in Sport Group has held meetings and developed five international statements on concussion in sport. This 6th statement summarises the processes and outcomes of the 6th International Conference on Concussion in Sport held in Amsterdam on 27-30 October 2022 and should be read in conjunction with the (1) methodology paper that outlines the consensus process in detail and (2) 10 systematic reviews that informed the conference outcomes. Over 3½ years, author groups conducted systematic reviews of predetermined priority topics relevant to concussion in sport. The format of the conference, expert panel meetings and workshops to revise or develop new clinical assessment tools, as described in the methodology paper, evolved from previous consensus meetings with several new components. Apart from this consensus statement, the conference process yielded revised tools including the Concussion Recognition Tool-6 (CRT6) and Sport Concussion Assessment Tool-6 (SCAT6, Child SCAT6), as well as a new tool, the Sport Concussion Office Assessment Tool-6 (SCOAT6, Child SCOAT6). This consensus process also integrated new features including a focus on the para athlete, the athlete's perspective, concussion-specific medical ethics and matters related to both athlete retirement and the potential long-term effects of SRC, including neurodegenerative disease. This statement summarises evidence-informed principles of concussion prevention, assessment and management, and emphasises those areas requiring more research.

The independent and joint association of accelerometer-measured physical activity and sedentary time with dementia: a cohort study in the UK Biobank

BACKGROUND

Research on the association of physical activity and sedentary time with dementia is accumulating, though elusive, and the interaction effects of the two remain unclear. We analysed the joint associations of accelerometer-measured physical activity and sedentary time with risk of incident dementia (all-cause dementia, Alzheimer's disease and vascular dementia).

METHODS

A total of 90,320 individuals from the UK Biobank were included. Accelerometer-measured total volume of physical activity (TPA) and sedentary time were measured at baseline and dichotomised by median (low TPA [< 27 milli-gravity (milli-g)], high TPA [≥ 27 milli-g]; low sedentary time [< 10.7 h/day], high sedentary time [≥ 10.7 h/day]). Cox proportional hazards models were used to evaluate the joint associations with incident dementia on both additive and multiplicative scales.

RESULTS

During a median follow-up of 6.9 years, 501 cases of all-cause dementia were identified. Higher TPA was associated with a lower risk of all-cause dementia, Alzheimer's disease and vascular dementia; the multivariate adjusted hazard ratios (HRs) (95% CI) per 10 milli-g increase were 0.63 (0.55-0.71), 0.74 (0.60-0.90) and 0.69 (0.51-0.93), respectively. Sedentary time was only found to be linked to all-cause dementia, and the HR for high sedentary time was 1.03 (1.01-1.06) compared with that for low sedentary time. No additive and multiplicative relationship of TPA and sedentary time to incident dementia was found (all P values > 0.05).

CONCLUSION

Higher TPA level was related to a lower risk of incident dementia irrespective of sedentary time, which highlighted the implication of promoting physical activity participation to counteract the potential detrimental effect of sedentary time on dementia.

Spicy food intake predicts Alzheimer-related cognitive decline in older adults with low physical activity

A plausible association exists among spicy food consumption, physical activity, and Alzheimer's disease (AD) or cognitive decline, but it remains poorly investigated. We aimed to examined the association between spicy food and AD-related memory decline or global cognitive decline in older adults under the moderating effect of physical activity. Total 196 non-demented older adults were included. Participants underwent comprehensive dietary and clinical assessments including spicy food intake, AD-related memory, global cognition, and physical activity. The strength of spicy food was stratified into three categories: 'not spicy' (reference), 'low spiciness', and 'high spiciness'. Multiple linear regression analyses were performed to examine the relationships between spicy level and cognition. The spicy level was the independent variable in each analysis; it was entered as a stratified categorical variable using the three categories. We found a significant association between a high level of spiciness in food and decreased memory ([Formula: see text] - 0.167, p < 0.001) or global cognition ([Formula: see text] - 0.122, p = 0.027), but not non-memory cognition. To explore the moderating effects of age, sex, apolipoprotein E ε4 allele-positivity, vascular risk score, body mass index, and physical activity on the associations between spicy level and memory or global cognition, the same regression analyses were repeated including two-way interaction terms between the spicy level and each of the six variables as an additional independent variable. An interactive effect was detected between a high level of spiciness in food and physical activity on the memory ([Formula: see text] 0.209, p = 0.029) or global cognition ([Formula: see text] 0.336, p = 0.001). Subgroup analyses showed that the association between a high level of spiciness in food and a lower memory ([Formula: see text] - 0.254, p < 0.001) and global score ([Formula: see text] - 0.222, p = 0.002) was present only in older adults with low physical activity, but not in older adults with high physical activity. Our findings suggest that spicy food intake is predictive of AD-related cognitive decline, i.e., episodic memory; this relationship is worsened by physically inactive lifestyle.

Adherence to the Mediterranean diet and waist-to-hip ratio in middle-aged postmenopausal women are the main factors associated with semantic verbal fluency 12 years later

Few studies have analized the effect of vascular risk factors and lifestyle habits affecting the middle age of postmenopausal women on later cognitive performance in old age. We have carried out an observational study to identify those factors and whether they differ from those acting in men. Postmenopausal women and males, both aged 40-60  years old at recruitment, from a community dwelling cohort were included. Data for this study were collected from the first visit at recruitment (2001 to 2005). Participants were interviewed with a questionnaire on their health-related antecedents and underwent a physical exam. The cohort was contacted again for a new presential visit between 2014 and 2015. A semantic verbal fluency test was included in this new visit protocol as a brief measure of cognition. Besides educational attainment, Mediterranean diet adherence 20th percentile (OR = 1.93; 95%CI = 1.07-3.47) and waist to hip ratio 80th percentile (OR = 1.81; 95%CI = 1.10-2,98) were the main factors associated to low semantic fluency performance in postmenopausal women, while declared diabetes mellitus (OR = 2.24; 95%CI = 1.16-4,33), HOMA 2 insulin resistance index (OR = 1.77; 95%CI =1.04-3,02), light physical activity in leisure time (OR = 0.41; 95%CI = 0.19-0,93) and recommended moderate to vigorous physical activity (OR = 2.09; 95%CI = 1.23-3.56) did in men. Factors in middle age that explain semantic verbal fluency in old age are different between postmenopausal women and men. Menopause related fat redistribution may be a precondition for other vascular risk factors. The effect of Mediterranean diet on cognition deserves new specific studies centered on postmenopausal women as group.

Incidence of memory complaints during the COVID-19 pandemic in Southern Brazil: findings from PAMPA cohort

Population-level studies investigating the incidence of memory complaints during the COVID-19 pandemic are scarce.

Objective

This study aimed to examine the incidence of memory complaints over 15 months during the COVID-19 pandemic in adults from Southern Brazil.

Methods

Data from the PAMPA (Prospective Study about Mental and Physical Health in Adults) cohort, a longitudinal study with adults residing in Southern Brazil, were analyzed. An online-based, self-administered questionnaire was used to assess self-rated memory. Participants rated their memories as excellent, very good, good, fair, or poor. Incident memory complaints were defined as worse memory perception from baseline to follow-up. Cox proportional hazard models were used to identify factors associated with the increased risk of memory complaints.

Results

During follow-up, a cumulative incidence of 57.6% for memory complaints was observed. Female sex (hazard ratio [HR] 1.49; 95% confidence intervals [CI] 1.16-1.94), lack of access to prescribed medicine (HR: 1.54; 95%CI 1.06-2.23), and worsened anxiety symptoms (HR: 1.81; 95%CI 1.49-2.21) were associated with an increased risk of memory complaints. Regular practice of physical activity was associated with a reduced risk of memory complaints (HR: 0.65; 95%CI 0.57-0.74).

Conclusion

Since the COVID-19 pandemic, 6 in 10 adults in Southern Brazil have developed memory complaints. Factors including sex and lack of medications increased the risk of incident memory complaints. Physical activity reduced the risk of incident memory complaints during the COVID-19 pandemic.

Association Between 24-Hour Movement Behavior and Cognitive Function in Brazilian Middle-Aged and Older Adults: Findings From the ELSA-Brasil

Background and Objectives

The relationship between 24-hr movement behavior and specific domains of cognitive function is unclear. The purpose of this study was to identify the joint association of daily time spent in light (light-intensity physical activity [LPA]) and moderate-to-vigorous physical activity (MVPA), sedentary behavior (SB), and sleep with cognitive function in middle-aged and older adults.

Research Design and Methods

Cross-sectional data from Wave 3 (2017-2019) of the Brazilian Longitudinal Study of Adult Health were analyzed. The study included adults aged 41-84 years old. Physical activity was assessed using a waist-worn accelerometer. Cognitive function was examined using standardized tests to assess memory, language, and Trail-Making test. Global cognitive function score was calculated by averaging domain-specific scores. Compositional isotemporal substitution models were performed to identify the association between the reallocation of time spent in LPA, MVPA, sleep, and SB with cognitive function.

Results

Participants (n = 8,608) were 55.9% female (mean age 58.9 [8.6] years). Reallocating time from SB to MVPA was associated with higher cognitive function: Reallocating 15 min to MVPA by reducing 5 min from each other behavior was associated with increased odds of better cognitive function in both insufficient (<7 hr/day; odds ratio [OR]: 0.64; 95% confidence interval [CI]: 0.54-0.77) and sufficient (≥7 hr/day; OR: 0.62; 95% CI: 0.58-0.67) sleep groups. Among those with insufficient sleep, reallocating time to MVPA and sleep from SB was associated with higher global cognitive performance.

Discussion and Implications

Small reductions in SB and increments in MVPA were associated with higher cognitive function in middle-aged and older adults.

Physical activity for cognitive health promotion: An overview of the underlying neurobiological mechanisms

Physical activity is one of the modifiable factors of cognitive decline and dementia with the strongest evidence. Although many influential reviews have illustrated the neurobiological mechanisms of the cognitive benefits of physical activity, none of them have linked the neurobiological mechanisms to normal exercise physiology to help the readers gain a more advanced, comprehensive understanding of the phenomenon. In this review, we address this issue and provide a synthesis of the literature by focusing on five most studied neurobiological mechanisms. We show that the body's adaptations to enhance exercise performance also benefit the brain and contribute to improved cognition. Specifically, these adaptations include, 1), the release of growth factors that are essential for the development and growth of neurons and for neurogenesis and angiogenesis, 2), the production of lactate that provides energy to the brain and is involved in the synthesis of glutamate and the maintenance of long-term potentiation, 3), the release of anti-inflammatory cytokines that reduce neuroinflammation, 4), the increase in mitochondrial biogenesis and antioxidant enzyme activity that reduce oxidative stress, and 5), the release of neurotransmitters such as dopamine and 5-HT that regulate neurogenesis and modulate cognition. We also discussed several issues relevant for prescribing physical activity, including what intensity and mode of physical activity brings the most cognitive benefits, based on their influence on the above five neurobiological mechanisms. We hope this review helps readers gain a general understanding of the state-of-the-art knowledge on the neurobiological mechanisms of the cognitive benefits of physical activity and guide them in designing new studies to further advance the field.

Mechanisms and Clinical Manifestations of Cognitive Decline in Atrial Fibrillation Patients: Potential Implications for Preventing Dementia

Atrial fibrillation (AF) patients face an approximate 1.5-fold increased risk of cognitive decline compared with the general population. Among poststroke AF patients, the risk of cognitive decline is even higher with an estimated threefold increase. This article provides a narrative review on the current evidence and highlights gaps in knowledge and areas for future research. Although earlier studies hypothesized that the association between AF and cognitive decline is mainly a consequence of previous ischemic strokes, more recent evidence also suggests such an association in AF patients without a history of clinical stroke. Because AF and cognitive decline mainly occur among elderly individuals, it is not surprising that both entities share multiple risk factors. In addition to clinically overt ischemic strokes, silent brain infarcts and other brain injury are likely mechanisms for the increased risk of cognitive decline among AF patients. Oral anticoagulation for stroke prevention in AF patients with additional stroke risk factors is one of the only proven therapies to prevent brain injury. Whether a broader use of oral anticoagulation, or more intense anticoagulation in some patients are beneficial in this context needs to be addressed in future studies. Although direct studies are lacking, it is reasonable to recommend optimal treatment of comorbidities and risk factors for the prevention of cognitive decline and dementia.