Leisure time physical activity and dementia risk: a dose-response meta-analysis of prospective studies

The impact of exercise on blood-based biomarkers of Alzheimer's disease in cognitively unimpaired older adults

Physical activity is a promising preventative strategy for Alzheimer's disease: it is associated with lower dementia risk, better cognition, greater brain volume and lower brain beta-amyloid. Blood-based biomarkers have emerged as a low-cost, non-invasive strategy for detecting preclinical Alzheimer's disease, however, there is limited literature examining the effect of exercise (a structured form of physical activity) on blood-based biomarkers. The current study investigated the influence of a 6-month exercise intervention on levels of plasma beta-amyloid (Aβ42, Aβ40, Aβ42/40), phosphorylated tau (p-tau181), glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) chain in cognitively unimpaired older adults, and as a secondary aim, whether blood-based biomarkers related to cognition. Ninety-nine community-dwelling older adults (69.1 ± 5.2) were allocated to an inactive control, or to moderate or high intensity exercise groups where they cycled twice weekly for six months. At baseline and six months (post-intervention), fasted blood was collected and analysed using single molecule array (SIMOA) assays, and cognition was assessed. Results demonstrated no change in levels of any plasma biomarker from pre- to post-intervention. At baseline, higher NfL was associated with poorer cognition (β = -0.33, SE = 0.13, adjusted p = .042). Exploratory analyses indicated higher cardiorespiratory fitness was associated with higher NfL and GFAP levels in apolipoprotein E (APOE) ε4 non-carriers compared to ε4 carriers (NfL, β = -0.43, SE = 0.19, p = .029; GFAP, β = -0.41, SE = 0.20, p = .044), though this association was mediated by body mass index (BMI). These results highlight the importance of considering BMI in analysis of blood-based biomarkers, especially when investigating differences between APOE ε4 carriers and non-carriers. Our results also indicate that longer follow-up periods may be required to observe exercise-induced change in blood-based biomarkers.

Relationships of Physical Activity and Type 2 Diabetes With Cognition in Mexican Americans and Non-Hispanic Whites

Problem, Research Strategy, and Findings: Low physical activity (PA) and Type 2 diabetes are associated with cognitive aging and Alzheimer's disease, but the evidence is inconsistent and particularly limited by ethnicity. The purpose of this study was to examine the relationships of PA and Type 2 diabetes with cognition in Mexican Americans and non-Hispanic Whites. The study was a cross-sectional analysis of the Health and Aging Brain Study-Health Disparities (n = 1,982-2,000 after removing outliers). Predictors included Rapid Assessment of Physical Activity and hemoglobin A1c (HbA1c). Episodic memory was assessed by Weschler Memory Scale-Third Edition Logical Memory and Spanish-English Verbal Learning Test, executive function by Weschler Memory Scale-Third Edition Digit Span and Digit Symbol Substitution Test, verbal fluency by FAS and animal naming, and global cognition by the Mini-Mental State Examination. Results show that aerobic PA and HbA1c were not associated with domain-specific, or global cognition, but strength/flexibility PA was associated with FAS (b = 0.404, 95% CI [0.023, 0.761]). Higher aerobic PA was associated with greater verbal fluency for Mexican Americans (b = 0.294, 95% CI [0.96, 0.497]) only. HbA1c was negatively associated with Mini-Mental State Examination (b = 0.838, 95% CI [0.008, 1.656]). For low HbA1c, the association between aerobic PA and Digit Symbol Substitution Test was significant for non-Hispanic Whites (b = 0.838, 95% CI [0.008, 1.656]) in comparison to Mexican Americans. Takeaway for Practice: The relationships between PA, Type 2 diabetes, and cognition vary by cognitive domains and ethnicity. Increasing aerobic activities may be particularly important for Mexican Americans who have elevated HbA1c to potentially improve fluency or executive function.

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

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

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Perimenopausal Physical Activity and Dementia Risk: A Systematic Review

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

Association between garden work and risk of incident dementia in an older population in China: a national cohort study

OBJECTIVES

Evidence on the association between garden work and risk of incident dementia in the older Chinese population is limited. This study aimed to explore the association between the frequency of garden work and risk of incident dementia in an older population in China.

STUDY DESIGN

This was a national cohort study.

METHODS

This study analysed data from 8676 participants (median age: 86 years) from the Chinese Longitudinal Healthy Longevity Survey. Cox proportional hazard models were used to assess the association between the frequency of garden work and risk of incident dementia using hazard ratios (HRs) and 95% confidence intervals (CIs). Multiplicative and additive interaction effects were calculated between the frequency of garden work and age, sex or residence on incident dementia; subgroup analyses of the association were also conducted by age, sex and residence. In addition, sensitivity analyses were performed to assess the robustness of the results.

RESULTS

During 4.31 years (median) of follow-up, 633 participants developed dementia. Compared with participants who did not engage in garden work, the adjusted risk of incident dementia for those who regularly or almost daily engaged in garden work decreased by 28% (HR = 0.72, 95% CI: 0.57-0.93). An additive interaction effect between frequency of garden work and age on incident dementia was observed, with subgroup analyses demonstrating similar statistically significant associations among participants aged ≥85 years, women and city or town residents. Sensitivity analyses were consistent with the primary analysis in the present study.

CONCLUSIONS

Frequent engagement in garden work may be associated with a reduced risk of dementia and may be an effective measure to prevent incident dementia in the older population in China.

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

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

Critical periods for cognitive reserve building activities for late life global cognition and cognitive decline: the Sydney memory and aging cohort study

Cognitive, social, and physical activities, collectively linked to cognitive reserve, are associated with better late-life cognitive outcomes. To better understand the building of cognitive reserve, we investigated which of these activities, during which stages of life, had the strongest associations with late-life cognitive performance. From the Sydney Memory and Aging Study, 546 older Australians, who were community-dwelling and without a dementia diagnosis at recruitment (Mage 80.13 years, 52.2% female), were asked about their engagement in social, physical, and cognitive activities throughout young adulthood (YA), midlife (ML), and late-life (LL). Comprehensive neuropsychological testing administered biennially over 6 years measured baseline global cognition and cognitive decline. In our study, YA, but not ML nor LL, cognitive activity was significantly associated with late-life global cognition (β = 0.315, p < .001). A follow-up analysis pointed to the formal education component of the YA cognitive activity measure, rather than YA cognitive leisure activities, as a significant predictor of better late-life global cognition (β = 0.146, p = .003). YA social activity and LL cognitive activity were significantly associated with less cognitive decline (β = 0.023, p < .001, and β = 0.016, p = .022, respectively). Physical activity was not found to be associated with global cognition or cognitive decline. Overall, YA cognitive activity was associated with better late-life cognition, and YA social and LL cognitive activities were associated with less cognitive decline. Formal education emerges as the key contributor in the association between YA cognitive activity and late-life global cognition.

Socioeconomic status, lifestyle and risk of incident dementia: a prospective cohort study of 276730 participants

Healthy lifestyle might alleviate the socioeconomic inequities in health, but the extent of the joint and interactive effects of these two factors on dementia are unclear. This study aimed to detect the joint and interactive associations of socioeconomic status (SES) and lifestyle factors with incident dementia risk, and the underlying brain imaging alterations. Cox proportional hazards analysis was performed to test the joint and interactive associations. Partial correlation analysis was performed to reflect the brain imaging alterations. A total of 276,730 participants with a mean age of 55.9 (±8.0) years old from UK biobank were included. Over 8.5 (±2.6) years of follow-up, 3013 participants were diagnosed with dementia. Participants with high SES and most healthy lifestyle had a significantly lower risk of incident dementia (HR=0.19, 95% CI=0.14 to 0.26, P<2×10-16), Alzheimer's disease (AD, HR=0.19, 95% CI=0.13 to 0.29, P=8.94×10-15), and vascular dementia (HR=0.24, 95% CI=0.12 to 0.48, P=7.57×10-05) compared with participants with low SES and an unhealthy lifestyle. Significant interactions were found between SES and lifestyle on dementia (P=0.002) and AD (P=0.001) risks; the association between lifestyle and dementia was stronger among those of high SES. The combination of high SES and healthy lifestyle was positively associated with higher volumes in brain regions vulnerable to dementia-related atrophy. These findings suggest that SES and lifestyle significantly interact and influence dementia with its related brain structure phenotypes.

A retrospective analysis of serious adverse events and deaths in U.S.-based lifestyle clinical trials for cognitive health

Objective

This retrospective analysis examined serious adverse events (SAEs) and deaths in U.S. lifestyle clinical trials aimed at enhancing cognitive health in older adults.

Methods

Data was gathered from trials completed between January 1, 2000, and July 19, 2023, via ClinicalTrials.gov's API.

Results

Among these trials, 76% did not report results. The remaining studies fell into four intervention categories: Cognitive/Behavioral, Exercise/Movement, Diet/Supplement, and Multi-modal. When considering all trial types collectively, the findings suggest that lifestyle clinical trials are generally safe. There was no significant increase in the relative risk of experiencing an SAE in the intervention group compared to the control group. However, in terms of relative risk of death, an increase of 28% was observed in the intervention compared to the control, which was statistically significant (X2 (1, N = 36), p < 0.00688). Nevertheless, this increase did not surpass age-adjusted U.S. mortality rates. Assessing the data by intervention type, Diet/Supplement, and Multi-modal trials displayed an elevated relative risk of SAEs in the intervention. Diet/Supplement trials had a 16% increase (X2 (1, N = 2), p < 0.0263), and Multi-modal trials had a 365% increase (X2 (1, N = 5), p < 0.000213). Diet/Supplement trials also showed a 67% increased risk of death (X2 (1, N = 2), p < 0.000197).

Conclusions

These findings should be cautiously considered due to the low rate of reporting, but underscore the significance of reporting clinical trial results, enhancing transparency, and facilitating more accurate safety assessments in cognitive aging and lifestyle interventions for older adults.

The impact of exercise on Alzheimer's disease progression

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Association between chronic pain classes and cognitive function in older adults: A cross-sectional study based on latent class analysis

The purpose of this study was to identify latent classes of chronic pain in older adults based on perceptual, cognitive, behavioral, emotional and social factors, and to explore the associations between each class of chronic pain and different cognitive domains. A total of 629 participants were included. Three classes of chronic pain were identified: "episodic recurrent mild pain with good psychosocial state" (class 1), "episodic recurrent moderate pain with general psychosocial state" (class 2) and "continuous multilocational severe pain with attacks accompanied by poor psychosocial state and avoidance of activity" (class 3). After adjusting for relevant confounders, chronic pain presenting as class 1 was associated with worse memory; class 2 was associated with worse global cognitive function, memory, information processing speed, and executive function; and class 3 was additionally associated with worse attention compared to class 2. The findings contribute to the development of targeted programs for treating pain and improving cognitive functioning.

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

Importance

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

Objective

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

Data Sources

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

Study Selection

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

Data Extraction and Synthesis

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

Main Outcomes and Measures

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

Results

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

Conclusions and Relevance

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

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.

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.

Trajectories of occupational physical activity and risk of later-life mild cognitive impairment and dementia: the HUNT4 70+ study

Background

High levels of occupational physical activity (PA) have been linked to an increased risk of dementia. We assessed the association of trajectories of occupational PA at ages 33-65 with risk of dementia and mild cognitive impairment (MCI) at ages 70+.

Methods

We included 7005 participants (49.8% were women, 3488/7005) from the HUNT4 70+ Study. Group-based trajectory modelling was used to identify four trajectories of occupational PA based on national registry data from 1960 to 2014: stable low (30.9%, 2162/7005), increasing then decreasing (8.9%, 625/7005), stable intermediate (25.1%, 1755/7005), and stable high (35.2%, 2463/7005). Dementia and MCI were clinically assessed in 2017-2019. We performed adjusted multinomial regression to estimate relative risk ratios (RRR) with 95% confidence intervals (CI) for dementia and MCI.

Findings

902 participants were diagnosed with dementia and 2407 were diagnosed with MCI. Absolute unadjusted risks for dementia and MCI were 8.8% (95% CI: 7.6-10.0) and 27.4% (25.5-29.3), respectively, for those with a stable low PA trajectory, 8.2% (6.0-10.4) and 33.3% (29.6-37.0) for those with increasing, then decreasing PA; while they were 16.0% (14.3-17.7) and 35% (32.8-37.2) for those with stable intermediate, and 15.4% (14.0-16.8) and 40.2% (38.3-42.1) for those with stable high PA trajectories. In the adjusted model, participants with a stable high trajectory had a higher risk of dementia (RRR 1.34, 1.04-1.73) and MCI (1.80, 1.54-2.11), whereas participants with a stable intermediate trajectory had a higher risk of MCI (1.36, 1.15-1.61) compared to the stable low trajectory. While not statistically significant, participants with increasing then decreasing occupational PA had a 24% lower risk of dementia and 18% higher risk of MCI than the stable low PA group.

Interpretation

Consistently working in an occupation with intermediate or high occupational PA was linked to an increased risk of cognitive impairment, indicating the importance of developing strategies for individuals in physically demanding occupations to prevent cognitive impairment.

Funding

This work was supported by the National Institutes of Health (R01AG069109-01) and the Research Council of Norway (296297, 262700, 288083).

Falls and Sleep Disorders in Spanish Alzheimer's Disease in Nursing Homes: An Observational Study

OBJECTIVE

The main objective of this study was to establish a relationship between the number of falls and sleep problems experienced by patients with Alzheimer's disease.

MATERIALS AND METHODS

This was a cross-sectional study. A total of 114 Spanish aged people with Alzheimer's disease institutionalized in nursing homes and 80 independent Spanish aged people without neurodegenerative diseases living at home were enrolled in this study and completed in-person interviews and digital questionnaires.

RESULTS

The mean age was 78.98 ± 8.59 years. Sleep disorders were related to continuous stress (p = 0.001; OR = 4.729) and a high frequency of falls (p = 0.001; OR = 2.145), while predictor variables associated with falls in patients with Alzheimer's disease were continuous medical visits (β = 0.319, p < 0.001), family history of dementia (β = 0.212; p = 0.014), and sleep disorders (β = 0.235; p = 0.007). Second, the analysis showed that moderate physical activity (p = 0.001; OR = 0.147), continuous medical visits (p < 0.001; OR = 0.621), and high level of study (p = 0.011; OR = 0.334) were protective factors against Alzheimer's, while older age (p = 0.035; OR = 1.087), type II Diabetes Mellitus (p = 0.042; OR = 3.973), number of falls (p = 0.021; OR = 1.409), and daily drug intake (p = 0.001; OR = 1.437) were risk factors for Alzheimer's.

CONCLUSIONS

Sleep disturbances are related to stress and falls in a sample of 114 Spanish AD aged people institutionalized in nursing homes, and the falls they experience are related to ongoing medical visits, a history of dementia, and sleep disturbances. Therefore, a bidirectional relationship was established between falls and sleep disorders in these patients. Moreover, this study showed that a greater frequency of falls and high daily drug intake could constitute novel risk factors for Alzheimer's disease, in addition to already known factors, such as age and type II Diabetes Mellitus, while being physically active and a high level of studies are protective factors against Alzheimer's disease.

Minimal amount of exercise prevents incident dementia in cognitively normal older adults with osteoarthritis: a retrospective longitudinal follow-up study

Robust evidence suggests that regular exercise, including walking more than 6000 steps, is effective for preventing dementia; however, such activity is less feasible in older people with osteoarthritis (OA) or other motor disabilities. Therefore, we aimed to test whether the minimal amount of exercise (MAE) could help prevent dementia in older adults with OA. A retrospective longitudinal study was performed and a non-demented cohort (≥ 50-years-old) of 242 people (155 [64.0%] non-converters and 87 [36.0%] converters) from three centers in Taiwan was analyzed with a mean follow-up of 3.1 (range 0.3-5.9) and 2.9 (range 0.5-6.0) years, respectively. MAE was defined as walking for approximately 15-30 min or 1500-3000 steps. Rate of MAE (0, 1-2, or ≥ 3) within one week were defined as MAE-no, MAE-weekly, or MAE-daily, respectively. The incidence rates of dementia were compared between groups. Multivariate logistic regression and Cox proportional hazards analyses were used to study the influence of MAE on dementia occurrence. Age, education, sex, activities of daily living, neuropsychiatric symptoms, cognition, multiple vascular risk factors, and related medications were adjusted. Compared to the MAE-no group, the odds ratios for the incidents of dementia were 0.48 and 0.19 in the MAE-weekly and MAE-daily groups, respectively. In addition, older age, poorer cognition, poorer ADL performance, and congestive heart failure increased the incidence of dementia. Daily and weekly MAE prevented dementia in older adults with OA. As such, an informative public health policy may help promote adequate exercise in at-risk groups.

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.

A Retrospective Analysis of Serious Adverse Events and Deaths in US-Based Lifestyle Clinical Trials for Cognitive Health

This retrospective analysis assessed the serious adverse events and deaths reported in lifestyle clinical trials designed to enhance cognitive health in older adults living in the United States. Data was collected from studies conducted between January 1, 2000, and July 19, 2023, using the ClinicalTrials.gov application programming interface. Our query revealed that 76% of these studies did not report trial results. The remaining studies with reported results were categorized under one of four intervention types: Cognitive/Behavioral, Exercise/Movement, Diet/Supplement, and Multi-modal. When all trial types are considered together, the results indicate that lifestyle clinical trials are safe, with no significant increase in relative risk of experiencing an SAE in an intervention group over a control group. And although the increase in relative risk of death in an intervention group over a control group was significant at 28% (X2 (1, N = 36), p < 0.00688), the probability of death was not higher than the U.S. mortality rates by age. When assessing the data using intervention type, Diet/Supplement trials and Multi-modal trials both had an increase in relative risk of experiencing an SAE in the intervention over the control group, with Diet/Supplement trials at 16% (X2 (1, N = 2), p < 0.0263) and Multi-modal trials at 365% (X2 (1, N = 5), p < 0.000213). The Diet/Supplement trials also had an increased risk of death at 67% (X2 (1, N = 2), p < 0.000197). These results should be taken with careful consideration. Due to such a low reporting rate, the 36 studies included in this analysis do not accurately represent the majority of lifestyle clinical trials conducted in the U.S. This study is valuable in that it highlights the importance of reporting clinical trial results, which will improve transparency in trial results and allow for more accurate assessments of safety in the growing field of cognitive aging and lifestyle interventions for older adults.

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.

Why might urban tree canopy reduce dementia risk? A causal mediation analysis of 109,688 adults with 11 years of hospital and mortality records

Urban tree canopy is associated with lower dementia risk, but no mediation analysis has been attempted to reveal potential mechanisms. We examined 3,639 dementia diagnoses in 109,688 participants of the Sax Institute's 45 and Up Study. Adjusted models indicated ≥20% tree canopy lowered the odds of developing dementia by 14% over 11 years (Odds Ratio = 0.86, 95%CI = 0.79-0.93). Association between tree canopy and dementia was partially mediated by physical activity (4.5%) and absences of psychological distress (5.7%), social support (2.9%), sleep duration (2.3%) and diabetes (1.8%). Social loneliness and absence of heart disease or hypertension did not mediate the tree canopy-dementia association.

Impact of exercising alone and exercising with others on the risk of cognitive impairment among older Japanese adults

PURPOSE

This longitudinal study investigates the influence of the stratified frequency of exercising alone and exercising with others on the prevention of cognitive impairment among older Japanese adults.

METHODS

This four-year follow-up study targeted 4,358 individuals (mean age: 76.9 ± 5.6 years, female: 51.8%) who participated in an inventory mail survey in one region of Japan. The exercise forms surveyed involved the frequency of exercising alone and with others. Cognitive impairment was assessed using the nationally standardized dementia scale proposed by the Ministry of Health, Labour and Welfare of Japan. Adjusted Cox proportional-hazard models were used to examine the association between the exercise forms and the development of cognitive impairment, and calculate population-attributable fractions (PAFs).

RESULTS

The cumulative incidence of cognitive impairment throughout the study was 7.7%. Participants who exercised ≥ 2 times/week alone (hazard ratio [HR] = 0.78; 95% confidence interval [CI] = 0.61-0.998) had a lower risk of developing cognitive impairment than those who did not exercise alone. Similarly, participants who exercised ≥ 2 times/week with others (HR = 0.66; 95% CI = 0.47-0.94) showed a lower risk of developing cognitive impairment than those who did not exercise with others. The scenarios involving PAFs demonstrated that, if all participants exercised alone or with others ≥ 2 times/week, the risk of cognitive impairment decreased by 15.1% and 29.2%, respectively.

CONCLUSION

Both forms of exercise reduced the development of cognitive impairment, with exercising with others potentially being highly effective in preventing cognitive impairment.

Associations between physical activity and cognitive dysfunction in older companion dogs: results from the Dog Aging Project

Canine cognitive dysfunction (CCD) is a form of dementia that shares many similarities with Alzheimer's disease. Given that physical activity is believed to reduce risk of Alzheimer's disease in humans, we explored the association between physical activity and cognitive health in a cohort of companion dogs, aged 6-18 years. We hypothesized that higher levels of physical activity would be associated with lower (i.e., better) scores on a cognitive dysfunction rating instrument and lower prevalence of dementia, and that this association would be robust when controlling for age, comorbidities, and other potential confounders. Our sample included 11,574 companion dogs enrolled through the Dog Aging Project, of whom 287 had scores over the clinical threshold for CCD. In this observational, cross-sectional study, we used owner-reported questionnaire data to quantify dog cognitive health (via a validated scale), physical activity levels, health conditions, training history, and dietary supplements. We fit regression models with measures of cognitive health as the outcome, and physical activity-with several important covariates-as predictors. We found a significant negative relationship between physical activity and current severity of cognitive dysfunction symptoms (estimate =  - 0.10, 95% CI: - 0.11 to - 0.08, p < 0.001), extent of symptom worsening over a 6-month interval (estimate =  - 0.07, 95% CI: - 0.09 to - 0.05, p < 0.001), and whether a dog reached a clinical level of CCD (odds ratio = 0.53, 95% CI: 0.45 to 0.63, p < 0.001). Physical activity was robustly associated with better cognitive outcomes in dogs. Our findings illustrate the value of companion dogs as a model for investigating relationships between physical activity and cognitive aging, including aspects of dementia that may have translational potential for Alzheimer's disease. While the current study represents an important first step in identifying a relationship between physical activity and cognitive function, it cannot determine causality. Future studies are needed to rule out reverse causation by following the same dogs prospectively over time, and to evaluate causality by administering physical activity interventions.

Effects of physical activity and exercise interventions on Alzheimer's disease: an umbrella review of existing meta-analyses

INTRODUCTION

During the last decade, physical activity (PA) (or "exercise") has been identified as one of the main modifiable factors that influence the development of Alzheimer's disease (AD) pathophysiology. We performed an umbrella review to summarize the evidence on the association between PA/exercise and the risk of developing AD risk, and the effect of exercise interventions on the progression of AD.

METHODS

A systematic search was performed in PubMed, SportDiscus, Cochrane Library and Web of Science (March 2022) to identify meta-analyses assessing the association between PA and the incidence of AD, and assessing the effect of exercise interventions on patients with AD.

RESULTS

Twenty-one studies were included. The results with strongest evidence revealed the positive effects of PA on AD risk. Specifically, meeting the WHO recommendations for PA was associated with a lower risk of AD. They also revealed positive effects of exercise on cognitive function, physical performance, and functional independence.

CONCLUSIONS

There is strong evidence of a protective effect of regular PA against AD risk; however, the dose-response association remains unclear. Physical exercise seems to improve several dimensions in patients with AD, although research is warranted to elucidate the exercise characteristics that promote the greatest benefits.

Contribution of pain to subsequent cognitive decline or dementia: A systematic review and meta-analysis of cohort studies

BACKGROUND

Dementia is an urgent public health problem worldwide, and the determination of the contribution of pain to cognitive decline or dementia is significant for the prevention of dementia.

OBJECTIVE

To comprehensively explore the contribution of pain to subsequent cognitive decline or dementia and analyze possible influencing factors.

DESIGN

Systematic review and meta-analysis of cohort studies.

METHODS

We systematically searched MEDLINE, EMBASE, PsycINFO, CINAHL, Cochrane Library, China National Knowledge Internet, WANFANG DATA and VIP for cohort studies from database inception to January 21, 2022. Random-effects meta-analysis was used to pool odds ratios (ORs) and 95% confidence intervals (CIs) of incident cognitive decline or dementia among patients with pain. Subgroup analyses and meta-regression were used to explore the sources of heterogeneity.

RESULTS

A total of 35 cohort studies containing 1,122,503 participants were included. As a whole, pain (OR = 1.24; 95% CI = 1.17-1.31) was a risk factor for subsequent cognitive decline or dementia; headache, migraine, tension-type headache, widespread pain, and irritable bowel syndrome, but not burning mouth syndrome, were also risk factors. Pain increased the risk of all-cause dementia (OR = 1.26; 95% CI = 1.18-1.35), Alzheimer's disease (OR = 1.28; 95% CI = 1.12-1.47), and vascular dementia (OR = 1.31; 95% CI = 1.06-1.62). Pain interference (OR = 1.42; 95% CI = 1.16-1.74) was associated with an increased risk of cognitive decline or dementia, while pain intensity was not. Pooled results from studies with sample sizes less than 2000 or with relatively low quality showed that pain did not increase the risk of cognitive decline or dementia. There was no statistically significant increase in the risk of cognitive decline or dementia in people with pain aged ≥75 years.

CONCLUSIONS

Our results demonstrated that pain increased the risk of subsequent cognitive decline or dementia. Sample size, study methodological quality, types of pain, pain severity (pain interference), and age composition of the study population may affect the relationship between pain and cognitive decline or dementia.

REGISTRATION

PROSPERO (CRD42022316406).

Modifying effects of race and ethnicity and APOE on the association of physical activity with risk of Alzheimer's disease and related dementias

INTRODUCTION

We investigated whether the protective association of physical activity with risk of Alzheimer's disease and related dementias (ADRD) has genetic or behavioral variations.

METHODS

In the Multiethnic Cohort, we analyzed moderate or vigorous physical activity (MVPA) reported at ages 45 to 75 among 88,047 participants in relation to 13,039 incident diagnoses of late-onset ADRD identified in Medicare claims (1999 to 2014), by five racial and ethnic groups, hours sitting, and in a subset (16%), apolipoprotein E (APOE) genotype.

RESULTS

MVPA was inversely associated with ADRD (hazard ratio for ≥14 vs <2.5 hours/week: 0.83, 95% confidence interval [CI]: 0.76 to 0.90 in men; 0.88, 5% CI: 0.81 to 0.95 in women). The association was inverse in all racial and ethnic groups except Black participants (P-heterogeneity = 0.52), but stronger in individuals with lower levels of sitting duration or those who do not carry the APOE e4 risk allele.

DISCUSSION

The different effects of physical activity by sitting duration and APOE genotype warrant further research.

A Combination of Caffeine Supplementation and Enriched Environment in an Alzheimer's Disease Mouse Model

A variety of factors has been associated with healthy brain aging, and epidemiological studies suggest that physical activity and nutritional supplements such as caffeine may reduce the risk of developing dementia and, in particular, Alzheimer's disease (AD) in later life. Caffeine is known to act as a cognitive enhancer but has been also shown to positively affect exercise performance in endurance activities. We have previously observed that chronic oral caffeine supplementation and a treatment paradigm encompassing physical and cognitive stimulation by enriched environment (EE) housing can improve learning and memory performance and ameliorate hippocampal neuron loss in the Tg4-42 mouse model of AD. Here, we investigated whether these effects were synergistic. To that end, previous findings on individual treatments were complemented with unpublished, additional data and analyzed in depth by ANOVA followed by Bonferroni multiple comparison post tests. We further evaluated whether plasma neurofilament light chain levels reflect neuropathological and behavioral changes observed in the experimental groups. While a treatment combining physical activity and caffeine supplementation significantly improved learning and memory function compared to standard-housed vehicle-treated Tg4-42 in tasks such as the Morris water maze, no major additive effect outperforming the effects of the single interventions was observed.

Resistance Exercise Program in Cognitively Normal Older Adults: CERT-Based Exercise Protocol of the AGUEDA Randomized Controlled Trial

OBJECTIVES

To provide a comprehensive CERT (Consensus on Exercise Reporting Template)-based description of the resistance exercise program implemented in the AGUEDA (Active Gains in brain Using Exercise During Aging) study, a randomized controlled trial investigating the effects of a 24-week supervised resistance exercise program on executive function and related brain structure and function in cognitively normal older adults.

DESIGN AND PARTICIPANTS

90 cognitively normal older adults aged 65 to 80 were randomized (1:1) to a: 1) resistance exercise group; or a 2) wait-list control group. Participants in the exercise group (n = 46) performed 180 min/week of resistance exercise (3 supervised sessions per week, 60 min/session) for 24 weeks.

INTERVENTION

The exercise program consisted of a combination of upper and lower limb exercises using elastic bands and the participant's own body weight as the main resistance. The load and intensity were based on the resistance of the elastic bands (7 resistances), number of repetitions (individualized), motor complexity of exercises (3 levels), sets and rest (3 sets/60 sec rest), execution time (40-60 sec) and velocity (as fast as possible).

SETTINGS

The maximum prescribed-target intensity was 70-80% of the participants' maximum rate of perceived exertion (7-8 RPE). Heart rate, sleep quality and feeling scale were recorded during all exercise sessions. Those in the wait-list control group (n = 44) were asked to maintain their usual lifestyle. The feasibility of AGUEDA project was evaluated by retention, adherence, adverse events and cost estimation on the exercise program.

RESULTS AND CONCLUSIONS

This study details the exercise program of the AGUEDA trial, including well-described multi-language manuals and videos, which can be used by public health professionals, or general public who wish to implement a feasible and low-cost resistance exercise program. The AGUEDA exercise program seems to be feasible by the high retention (95.6%) and attendance rate (85.7%), very low serious adverse event (1%) and low economic cost (144.23 € /participant/24 weeks). We predict that a 24-week resistance exercise program will have positive effects on brain health in cognitively normal older adults.

The long-term relation between physical activity and executive function in the Rotterdam Study

BACKGROUND

Research on the association between physical inactivity and cognitive decline and dementia is dominated by studies with short-term follow-up, that might be biased by reverse causality.

OBJECTIVE

Investigate the long-term association between physical activity, cognition, and the rate of age-associated cognitive decline.

METHODS

We investigated the association between late-life physical activity and executive functioning and rate of decline of executive abilities during follow-up of up to 16 years, in 3553 participants of the prospective Rotterdam Study cohort. Measurement took place in 1997-1999, 2002-2004, 2009-2011, and 2014-2015.

RESULTS

At baseline (age ± 72 years), higher levels of physical activity were associated with higher levels of executive functioning (adjusted mean difference = 0.03, 95% CI: 0.00 ; 0.06, p = 0.03). This difference remained intact up to 16 years of follow-up. The level of physical activity at baseline was unrelated to the rate of decline of executive abilities over time, in the whole group (adjusted mean difference in change_{time*physical activity} = 0.00, 95% CI: -0.00 ; 0.01, p = 0.31). However, stratification by APOE genotype showed that the accelerated decline of executive abilities observed in those with the ApoE-ε4 allele might be attenuated by higher levels of physical activity in late adulthood (ApoE-ε4 carriers: B_{time*physical activity} = 0.01, 95% CI: 0.00 ; 0.01, p = 0.03).

CONCLUSION

Higher levels of physical activity in late adulthood are related to higher levels of executive functioning, up to 16 years of follow-up. Accelerated decline of executive abilities observed in those with the ApoE-ε4 allele might be mitigated by higher levels of physical activity.

Sleep, physical activity, sedentary behavior, and risk of incident dementia: a prospective cohort study of 431,924 UK Biobank participants

Although sleep, physical activity and sedentary behavior have been found to be associated with dementia risk, findings are inconsistent and their joint relationship remains unclear. This study aimed to investigate independent and joint associations of these three modifiable behaviors with dementia risks. A total of 431,924 participants (median follow-up 9.0 years) without dementia from UK Biobank were included. Multiple Cox regressions were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). Models fitted with restricted cubic spline were conducted to test for linear and nonlinear shapes of each association. Sleep duration, leisure-time physical activity (LTPA), and screen-based sedentary behavior individually associated with dementia risks in different non-linear patterns. Sleep duration associated with dementia in a U-shape with a nadir at 7 h/day. LTPA revealed a curvilinear relationship with dementia in diminishing tendency, while sedentary behavior revealed a J-shaped relationship. The dementia risk was 17% lower in the high LTPA group (HR[95%CI]: 0.83[0.76-0.91]) and 22% higher in the high sedentary behavior group (1.22[1.10-1.35]) compared to the corresponding low-level group, respectively. A combination of seven-hour/day sleep, moderate-to-high LTPA, and low-to-moderate sedentary behavior showed the lowest dementia risk (0.59[0.50-0.69]) compared to the referent group (longer or shorter sleep/low LTPA/high sedentary behavior). Notably, each behavior was non-linearly associated with brain structures in a pattern similar to its association with dementia, suggesting they may affect dementia risk by affecting brain structures. Our findings highlight the potential to change these three daily behaviors individually and simultaneously to reduce the risk of dementia.

Dietary nitrate and brain health. Too much ado about nothing or a solution for dementia prevention?

Dementia is a significant public health priority with approximately 55 million cases worldwide, and this number is predicted to quadruple by 2050. Adherence to a healthy diet and achieving optimal nutritional status are vital strategies to improve brain health. The importance of this area of research has been consolidated into the new term ‘nutritional psychiatry’. Dietary nitrate, closely associated with the intake of fruits and vegetables, is a compound that is increased in dietary patterns such as the Mediterranean and MIND diets and has protective effects on cognition and brain health. Nitrate is characterised by a complex metabolism and is the precursor of the nitrate–nitrite–nitric oxide (NO) pathway contributing to systemic NO generation. A higher intake of dietary nitrate has been linked to protective effects on vascular outcomes including blood pressure and endothelial function. However, the current evidence supporting the protective effects of dietary nitrate on brain health is less convincing. This article aims to provide a critical appraisal of the current evidence for dietary nitrate supplementation for improving brain health and provide suggestions for future research.

Physical activity, memory function, and hippocampal volume in adults with Down syndrome

Higher engagement in moderate-intensity physical activity (PA) is related to better cognitive functioning in neurotypical adults; however, little is known about the effect of PA on cognitive aging in adults with Down syndrome (DS). Individuals with DS have three copies of chromosome 21, which includes the gene involved in the production of the amyloid precursor protein, resulting in an increased risk for an earlier onset of Alzheimer’s disease (AD). The goal of this study was to understand the relationship between engagement in moderate PA, memory, and hippocampal volume in adults with DS. Adults with DS participated in an ancillary Lifestyle study linked to the Alzheimer’s Biomarkers Consortium for DS (ABC- DS; N = 71). A within-sample z-score memory composite was created from performance on the Cued Recall Test (CRT) and the Rivermead Picture Recognition Test. Participants wore a wrist-worn accelerometer (GT9X) to measure PA. Variables of interest included the average percentage of time spent in moderate PA and average daily steps. Structural MRI data were acquired within 18 months of actigraphy/cognitive data collection for a subset of participants (n = 54). Hippocampal volume was extracted using Freesurfer v5.3. Associations between moderate PA engagement, memory, and hippocampal volume were evaluated with hierarchical linear regressions controlling for relevant covariates [age, body mass index, intellectual disability level, sex, and intracranial volume]. Participants were 37.77 years old (SD = 8.21) and were 55.6% female. They spent 11.1% of their time engaged in moderate PA (SD = 7.5%) and took an average of 12,096.51 daily steps (SD = 4,315.66). After controlling for relevant covariates, higher memory composite score was associated with greater moderate PA engagement (β = 0.232, p = 0.027) and more daily steps (β = 0.209, p = 0.037). In a subset of participants, after controlling for relevant covariates, PA variables were not significantly associated with the hippocampal volume (all p-values ≥ 0.42). Greater hippocampal volume was associated with higher memory composite score after controlling for relevant covariates (β = 0.316, p = 0.017). More PA engagement was related to better memory function in adults with DS. While greater hippocampal volume was related to better memory performance, it was not associated with PA. Greater PA engagement may be a promising lifestyle behavior to preserve memory in adults with DS.

Associations of Modifiable Behavioral Risk Factor Combinations at 65 to 74 Years Old With Cognitive Health Span for 20 Years

OBJECTIVE

Behavioral risk factors for dementia tend to co-occur and interrelate, especially poor diet, physical inactivity, sleep disturbances, and depression. Having multiple of these modifiable behavioral risk factors (MBRFs) may predict a particularly shortened cognitive health span and therefore may signal high-risk status/high intervention need.

METHODS

These secondary analyses of data from the Cardiovascular Health Study included 3149 participants aged 65 to 74 years (mean [standard deviation {SD}] age = 69.5 [2.5] years; 59.6% female). MBRF exposures were self-reports regarding a) diet, b) activity, c) sleep, and d) depression symptoms. We primarily analyzed MBRF counts. For up to 26 years of follow-up, we assessed the a) number of remaining cognitively healthy life-years (CHLYs) and b) percentage of remaining life-years (LYs) that were CHLYs (%CHLY). We estimated CHLYs as time before a dementia diagnosis, cognitive screener scores indicating impairment, proxy report indicating significant cognitive decline, or dementia medication use.

RESULTS

Participants averaged a remaining 16 LYs (SD = 7 LYs), 12.2 CHLYs (SD = 6.6 CHLYs), and 78.1% of LYs being CHLYs (SD = 25.6 CHLYs). Compared with having no MBRFs, having one was associated with ~1 less LY and CHLY, but not a relatively lower %CHLY. In contrast, having 3+ MBRFs was associated with about 2 to 3 fewer LYs and CHLYs as well as about 6% lower %CHLY (95% confidence interval = -9.0 to -2.5 %CHLYs; p = .001).

CONCLUSIONS

MBRF-related reductions in the cognitive health span are most apparent when people have multiple MBRFs. Future research is needed to determine if/how behavioral risks converge mechanistically and if dementia prevention efficacy improves when targeting MBRF combinations.

Sex-specific longitudinal association between baseline physical activity level and cognitive decline in Chinese over 45 years old: Evidence from the China health and retirement longitudinal study

OBJECTIVES

To examine whether sex-specific associations between baseline PA level and follow up cognitive performance in Chinese subjects exist from the China Health and Retirement Longitudinal study (CHARLS).

METHOD

A total of 3395 adults aged 45 or old from the CHARLS were used for analysis. The combined scores of measurements of mental status and verbal episodic memory were utilized for assessing cognitive function at baseline in 2011 and the follow-up survey in 2015. Baseline PA level was quantified as the total PA score. Multiple linear regression and logistic regression models were used to examine the association between baseline PA status and global cognitive function and cognitive domains.

RESULTS

In the female subjects (n = 1748), compared with individuals of PA level in the lower tertile, those grouped into the upper tertile had the lowest risk of global cognitive decline [odds ratio (OR) =0.273, 95% confidence interval (CI) =0.077-0.960; p = 0.043] and verbal episodic memory decline [OR)=0.257, 95% CI =0.066-1.003; p = 0.051] from 2011 to 2015. However, no significant associations were observed in the male subjects (n = 1647).

CONCLUSION

In the female subjects, higher PA level was associated with reduced risk of cognitive decline within 4 years, this might be associated with reduced decline of verbal episodic memory. Our findings confirmed that female sex would positively affect the association between PA levels and cognitive decline.

Relationship between physical activity and incidence of dementia in people aged 50 and over in Europe

OBJECTIVE

The aim of this study was to analyse the relationship between physical activity and the incidence of dementia in a cohort of people aged 50 years or older without dementia from different countries in Europe between the years 2013 and 2015.

METHODS

Prospective longitudinal design study (2013-2015) with a sample of 46,141 people without dementia in 2013 who participated in the SHARE project in waves 5 and 6, where 15 European countries participated. We defined dementia as a self-report of Alzheimer's disease, organic brain syndrome, senility, or any other serious memory impairment during follow-up. The frequency of moderate, vigorous and moderate-to-vigorous physical activity in 2013 was obtained from a validated questionnaire. Incidences of dementia by year (between 2013 and 2015) were calculated for each category of physical activity. Poisson regression models with robust variance were fitted for the association between physical activity and dementia.

RESULTS

The incidence of dementia was 7.4 [95%CI = 6.8-7.9] cases per 1000 persons per year. Very frequent moderate physical activity is a protective factor for dementia independently of the frequency of vigorous physical activity and inversely. The risk of dementia was 2.36 [95%CI = 1.77-3.14] higher in people who hardly ever, or never did moderate-to-vigorous physical activity comparing to people engaged in it more than once a week independently of the baseline cognitive level.

CONCLUSION

Physical activity is associated with the incidence of dementia in people aged 50 and over in both men and women in Europe.

Associations of Physical Activity with Alzheimer’s Disease Pathologies and Cognition: The CABLE Study

Background: The associations of physical activity with Alzheimer’s disease (AD) pathologies remain controversial. Objective: To quantitatively assess the association between the frequency of physical activity with cerebrospinal fluid (CSF) biomarkers in AD and further explore the mechanism by which AD pathologies regulate the correlation between physical activity and cognition. Methods: A total of 918 participants without dementia from Chinese Alzheimer’s Biomarker and Lifestyle (CABLE) were examined in this population-based cross-sectional study. Multiple linear models were used to evaluate the associations of physical activity with CSF biomarkers and cognition. Moreover, mediation analyses were conducted to investigate the potential relationships between physical activity, AD pathologies, and cognitive function. Results: Regular physical activity was positively associated with CSF Aβ 42 (p <  0.001) and Aβ 42/40 (p <  0.001), while it was negatively associated with p-tau/Aβ 42 (p <  0.001) and t-tau/Aβ 42 (p <  0.001). Of all participants, regular physical activity was associated with increased cognitive function (p <  0.001). The interaction effect indicated that age moderated the association between physical activity frequency and CSF Aβ 42 (p = 0.014) and p-tau/Aβ 42 (p = 0.041). The impact of physical activity on cognition was mediated in part by amyloid pathologies, accounting for 4.87% to 21.56% of the total effect (p <  0.05). Conclusion: This study showed the beneficial impact of physical activity on AD pathologies and cognition in participants without dementia.

Computerised cognitive training tools and online nutritional group counselling for people with mild cognitive impairment: study protocol of a completely digital, randomised, controlled trial

INTRODUCTION

People with mild cognitive impairment (MCI) are at increased risk of decreasing cognitive functioning. Computerised cognitive training (CCT) and nutrition have been shown to improve the cognitive capacities of people with MCI. For each variable, we developed two kinds of interventions specialised for people with MCI (CCT: 'individualised' CCT; nutrition: a whole-food, plant-based diet). Additionally, there are two kinds of active control measures (CCT: 'basic' CCT; nutrition: a healthy diet following the current guidelines of the German Nutrition Society). The aim of this study is to investigate the effects of the two interventions on cognition in people with MCI in a 2×2 randomised controlled trial with German participants.

METHODS AND ANALYSIS

Participants will be community-dwelling individuals with a psychometric diagnosis of MCI based on the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination. With N=200, effects with an effect size of f≥0.24 (comparable to Cohen's d≥0.48) can be detected. Screening, baseline, t6 and t12 testing will be conducted via a videoconferencing assessment, telephone, and online survey. Participants will be randomly allocated to one of four groups and will receive a combination of CCT and online nutritional counselling. The CCT can be carried out independently at home on a computer, laptop, or tablet. Nutrition counselling includes 12 online group sessions every fortnight for 1.5 hours. The treatment phase is 6 months with follow-ups after six and 12 months after baseline.

ETHICS AND DISSEMINATION

All procedures were approved by the Friedrich-Alexander-Universität Erlangen-Nürnberg Ethics Committee (Ref. 21-318-1-B). Written informed consent will be obtained from all participants. Results will be published in peer-reviewed scientific journals, conference presentations.

TRIAL REGISTRATION NUMBER

ISRCTN10560738.

Identifying the Relationship between Leisure Walking and Prevalence of Alzheimer’s Disease and Other Dementias

The literature suggests that leisure walking can play an important role in preventing dementia. The purpose of the present study was to investigate the relationship between leisure walking and the prevalence of Alzheimer’s disease (AD) and other dementias among older adults. Using the 2020 Health and Retirement Study (HRS), 4581 responses constituted the sample for the present study. A hierarchical logit regression analysis was conducted to investigate the relationship between leisure walking and the prevalence of AD and dementia. The results show that leisure walking has been negatively associated with the prevalence of AD and other dementias—that is, they indicate that older adults who frequently engaged in leisure walking were less likely to develop AD and other dementias. This finding suggests the importance of leisure walking as a dementia prevention program for older adults.

Physical Activity Intensity and Suspected Dementia in Older Japanese Adults: A Dose-Response Analysis Based on an 8-Year Longitudinal Study

Background: Moderate- to vigorous-intensity physical activity (PA) may reduce the risk of dementia; however, few studies have examined the effects of PA intensity on dementia risk. Objective: To prospectively examine the dose-response relationship of PA intensity with the incidence of suspected dementia in community-dwelling older adults. Methods: We conducted a baseline mail survey with an 8-year follow-up of 3,722 older adults in Japan. We assessed PA levels using the International Physical Activity Questionnaire short form and calculated the amount of time per week spent performing moderate- and vigorous-intensity PA (VPA). Information regarding suspected dementia was obtained from the city database during the follow-up period. Cox proportional-hazard models with age as time scale, and delayed entry and restricted cubic spline regression as variables were used to estimate risk of developing suspected dementia, excluding cases occurring <  1 year after baseline evaluation. Results: The cumulative incidence of suspected dementia during the follow-up period was 12.7% . Compared with those who did not practice moderate-intensity PA (MPA), those who practiced≥300 min (hazard ratio, 0.73; 95% confidence interval 0.56–0.95) of MPA showed a lower risk of developing suspected dementia. Furthermore, when the dose-response relationship was examined, the hazard of developing suspected dementia decreased almost linearly with MPA. A significantly lower hazard was observed from 815 minutes/week. There was no significant association between VPA and suspected dementia. Conclusion: This study suggested that MPA is often practiced in older adults and this PA intensity has a sufficiently favorable effect on dementia prevention.

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

Objective

Physical activity (PA) is associated with a decreased incidence of dementia, but much of the evidence comes from short follow-ups prone to reverse causation. This meta-analysis investigates the effect of study length on the association.

Design

A systematic review and meta-analysis. Pooled effect sizes, dose–response analysis and funnel plots were used to synthesise the results.

Data sources

CINAHL (last search 19 October 2021), PsycInfo, Scopus, PubMed, Web of Science (21 October 2021) and SPORTDiscus (26 October 2021).

Eligibility criteria

Studies of adults with a prospective follow-up of at least 1 year, a valid cognitive measure or cohort in mid-life at baseline and an estimate of the association between baseline PA and follow-up all-cause dementia, Alzheimer’s disease or vascular dementia were included (n=58).

Results

PA was associated with a decreased risk of all-cause dementia (pooled relative risk 0.80, 95% CI 0.77 to 0.84, n=257 983), Alzheimer’s disease (0.86, 95% CI 0.80 to 0.93, n=128 261) and vascular dementia (0.79, 95% CI 0.66 to 0.95, n=33 870), even in longer follow-ups (≥20 years) for all-cause dementia and Alzheimer’s disease. Neither baseline age, follow-up length nor study quality significantly moderated the associations. Dose–response meta-analyses revealed significant linear, spline and quadratic trends within estimates for all-cause dementia incidence, but only a significant spline trend for Alzheimer’s disease. Funnel plots showed possible publication bias for all-cause dementia and Alzheimer’s disease.

Conclusion

PA was associated with lower incidence of all-cause dementia and Alzheimer’s disease, even in longer follow-ups, supporting PA as a modifiable protective lifestyle factor, even after reducing the effects of reverse causation.

Can exercise training teach us how to treat Alzheimer's disease?

Alzheimer's disease (AD) is the most common cause of dementia and there is currently no cure. Novel approaches to treat AD and curb the rapidly increasing worldwide prevalence and costs of dementia are needed. Physical inactivity is a significant modifiable risk factor for AD, estimated to contribute to 12.7% of AD cases worldwide. Exercise interventions in humans and animals have shown beneficial effects of exercise on brain plasticity and cognitive functions. In animal studies, exercise also improved AD pathology. The mechanisms underlying these effects of exercise seem to be associated mainly with exercise performance or cardiorespiratory fitness. In addition, exercise-induced molecules of peripheral origin seem to play an important role. Since exercise affects the whole body, there likely is no single therapeutic target that could mimic all the benefits of exercise. However, systemic strategies may be a viable means to convey broad therapeutic effects in AD patients. Here, we review the potential of physical activity and exercise training in AD prevention and treatment, shining light on recently discovered underlying mechanisms and concluding with a view on future development of exercise-free treatment strategies for AD.

Leisure-Time and Non-Leisure-Time Physical Activities Are Dose-Dependently Associated With a Reduced Risk of Dementia in Community-Dwelling People Aged 40-74 Years: The Murakami Cohort Study

OBJECTIVE

Although physical activity (PA) in late life is considered a preventive factor for dementia, effects of different types of PAs on the development of dementia in early old age are unclear. This study aimed to determine the effect of leisure-time and non-leisure-time PAs on dementia risk in middle-aged and older adults during an 8-year follow-up.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

Participants were 13,773 community-dwelling individuals aged 40-74 years who completed the baseline self-administered questionnaire survey of the Murakami cohort study in 2011-2013.

METHODS

Main predictors were leisure-time and non-leisure-time (commute, occupational work, and housework) PAs as assessed by MET score (MET-hour/d). The outcome was newly developed dementia determined using a long-term care insurance database. Covariates included demographics, lifestyle, body size, disease history, and PA level. Hazard ratios (HRs) were calculated using Cox proportional hazards models.

RESULTS

Mean age of participants was 59.0 (SD 9.3) years. Higher levels of leisure-time PA were associated with lower HRs (adjusted P for trend <.001), with all tertiles having significantly lower HRs (low: 0.71, 95% CI 0.51-0.99; medium: 0.59, 95% CI 0.43-0.81; high: 0.55, 95% CI 0.41-0.75) relative to the reference (zero). Higher quartiles of non-leisure-time PA were associated with lower adjusted HRs for dementia (adjusted P for trend < .001), with the second-fourth quartiles having significantly lower HRs (second: 0.73, 95% CI 0.54-0.98; third: 0.59, 95% CI 0.43-0.81; fourth: 0.55, 95% CI 0.41-0.75) relative to the lowest quartile. These associations were robust regardless of sex and age group.

CONCLUSIONS AND IMPLICATIONS

Both leisure-time and non-leisure-time PAs are independently and robustly associated with a reduced risk of dementia.

A personalized mobile app for physical activity: An experimental mixed-methods study

Objectives

To investigate the feasibility of the be.well app and its personalization approach which regularly considers users’ preferences, amongst university students.

Methods

We conducted a mixed-methods, pre-post experiment, where participants used the app for 2 months. Eligibility criteria included: age 18–34 years; owning an iPhone with Internet access; and fluency in English. Usability was assessed by a validated questionnaire; engagement metrics were reported. Changes in physical activity were assessed by comparing the difference in daily step count between baseline and 2 months. Interviews were conducted to assess acceptability; thematic analysis was conducted.

Results

Twenty-three participants were enrolled in the study (mean age = 21.9 years, 71.4% women). The mean usability score was 5.6 ± 0.8 out of 7. The median daily engagement time was 2 minutes. Eighteen out of 23 participants used the app in the last month of the study. Qualitative data revealed that people liked the personalized activity suggestion feature as it was actionable and promoted user autonomy. Some users also expressed privacy concerns if they had to provide a lot of personal data to receive highly personalized features. Daily step count increased after 2 months of the intervention (median difference = 1953 steps/day, p-value <.001, 95% CI 782 to 3112).

Conclusions

Incorporating users’ preferences in personalized advice provided by a physical activity app was considered feasible and acceptable, with preliminary support for its positive effects on daily step count. Future randomized studies with longer follow up are warranted to determine the effectiveness of personalized mobile apps in promoting physical activity.

Exercise Dosage in Reducing the Risk of Dementia Development: Mode, Duration, and Intensity-A Narrative Review

Senile dementia, also known as dementia, is the mental deterioration which is associated with aging. It is characterized by a decrease in cognitive abilities, inability to concentrate, and especially the loss of higher cerebral cortex function, including memory, judgment, abstract thinking, and other loss of personality, even behavior changes. As a matter of fact, dementia is the deterioration of mental and intellectual functions caused by brain diseases in adults when they are mature, which affects the comprehensive performance of life and work ability. Most dementia cases are caused by Alzheimer’s disease (AD) and multiple infarct dementia (vascular dementia, multi-infarct dementia). Alzheimer’s disease is characterized by atrophy, shedding, and degenerative alterations in brain cells, and its occurrence is linked to age. The fraction of the population with dementia is smaller before the age of 65, and it increases after the age of 65. Since women live longer than men, the proportion of women with Alzheimer’s disease is higher. Multiple infarct dementia is caused by a cerebral infarction, which disrupts blood supply in multiple locations and impairs cerebral cortex function. Researchers worldwide are investigating ways to prevent Alzheimer’s disease; however, currently, there are no definitive answers for Alzheimer’s prevention. Even so, research has shown that we can take steps to reduce the risk of developing it. Prospective studies have found that even light to moderate physical activity can lower the risk of dementia and Alzheimer’s disease. Exercise has been proposed as a potential lifestyle intervention to help reduce the occurrence of dementia and Alzheimer’s disease. Various workout modes will be introduced based on various physical conditions. In general, frequent exercise for 6–8 weeks lessens the risk of dementia development.