Nutrition, Physical Activity, and Other Lifestyle Factors in the Prevention of Cognitive Decline and Dementia

Tailoring meat products for the elderly: A comprehensive review

The population of the elderly is projected to grow significantly in most of the developed countries in the near future. This should earn this demographic the title of 'Consumer of the future'. Meat has high quality proteins and essential vitamins which are important for all demographics but more so for the elderly due to their susceptibility to sarcopenia. This review explored the landscape of meat research and product development that meets the distinctive requirements of the elderly, drawing from published refereed articles, industry reports, and unpublished grey literature. The review emphasised the importance of understanding the evolving dietary and sensory requirements associated with ageing and how they intersect with meat consumption. One notable aspect observed is the diversity within the elderly population, which underscores the necessity for tailored approaches in meat product development to cater to the varying preferences and nutritional needs of different individuals. This review also highlights the ongoing efforts in developing meat-based products that span a spectrum of consistencies, ranging from solid to liquid forms, to accommodate the diverse needs of elderly consumers. Despite these advancements, the review found a discrepancy between the pace of meat product development for the elderly and the rapid advancements in kitchen-level technologies and suggests that further research is needed to bridge this gap and align product innovation with emerging technological trends.

Photobiomodulation in the aging brain: a systematic review from animal models to humans

Aging is a multifactorial biological process that may be associated with cognitive decline. Photobiomodulation (PBM) is a non-pharmacological therapy that shows promising results in the treatment or prevention of age-related cognitive impairments. The aim of this review is to compile the preclinical and clinical evidence of the effect of PBM during aging in healthy and pathological conditions, including behavioral analysis and neuropsychological assessment, as well as brain-related modifications. 37 studies were identified by searching in PubMed, Scopus, and PsycInfo databases. Most studies use wavelengths of 800, 810, or 1064 nm but intensity and days of application were highly variable. In animal studies, it has been shown improvements in spatial memory, episodic-like memory, social memory, while different results have been found in recognition memory. Locomotor activity improved in Parkinson disease models. In healthy aged humans, it has been outlined improvements in working memory, cognitive inhibition, and lexical/semantic access, while general cognition was mainly enhanced on Alzheimer disease or mild cognitive impairment. Anxiety assessment is scarce and shows mixed results. As for brain activity, results outline promising effects of PBM in reversing metabolic alterations and enhancing mitochondrial function, as evidenced by restored CCO activity and ATP levels. Additionally, PBM demonstrated neuroprotective, anti-inflammatory, immunomodulatory and hemodynamic effects. The findings suggest that PBM holds promise as a non-invasive intervention for enhancing cognitive function, and in the modulation of brain functional reorganization. It is necessary to develop standardized protocols for the correct, beneficial, and homogeneous use of PBM.

Association between life's essential 8 and cognitive impairment in older patients: results from NHANES 2011-2014

BACKGROUND

This study aimed to examine the association between the American Heart Association's (AHA) newly revised Life's Essential 8 (LE8) algorithm, designed for assessing cardiovascular health (CVH), and cognitive impairment among older adults in the United States.

METHODS

This study employed a cross-sectional design, utilizing data from the 2011-2014 National Health and Nutrition Examination Survey to explore the relationship between CVH and cognitive impairment in older adults. CVH scores are assessed based on the AHA definition of the LE8, categorized into three tiers: low (0-49), medium (50-79), and high (80-100). Cognitive impairment is evaluated using three distinct scoring systems: the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST). The lowest quartile as the cut-off point; below or equal to the lower quartile was considered as low cognitive population, and above the lower quartile was normal population. To analyze the association, multivariable logistic regression and restricted cubic spline (RCS) models were employed.

RESULTS

A significant negative correlation exists between the LE8 and cognitive impairment. After adjusting for multiple variables, the odds ratios (OR) for cognitive impairment, as measured by the CERAD, AFT, and DSST, were compared between patients with high and low CVH. The results indicated OR values of 0.60 (95% CI: 0.36-0.98), 0.72 (95% CI: 0.52-0.97), and 0.29 (95% CI: 0.16-0.53) for the CERAD, AFT, and DSST, respectively. Additionally, the RCS curve demonstrated a significant linear relationship between lifestyle factors encapsulated by the LE8 and cognitive impairment.

CONCLUSIONS

The findings indicate higher adherence to LE8 was associated with lower odds of cognitive impairment. Furthermore, maintaining optimal CVH is crucial in preventing cognitive impairment.

Effects of socio-therapeutic interventions on cognitive functions among institutionalized elderly

Cognitive impairment affects over one billion people globally, with elderly individuals in institutions in China being particularly impacted. This study involved 60 elderly participants with mild cognitive impairment, who were randomly assigned to one of two groups: 30 in a control group receiving traditional programs from the elderly institution and 30 in an intervention group receiving socio-therapeutic methods. Cognitive function was assessed before the intervention, and at the end of the first, second, and third months (with unsupervised interventions in the third month). Initially, both groups had similar low MMSE scores. However, the socio-therapeutic intervention led to significant cognitive improvements in the intervention group after the first and second months, with results remaining higher than the control group by the end of the third month. The study highlights the effectiveness of socio-therapeutic interventions in enhancing cognitive function and suggests that such programs should be adopted in elderly care institutions. Further research is needed to explore long-term effects and optimal program components, with personalized interventions and family/community involvement recommended to maximize benefits.

Cognitive Frailty and Aging: Clinical Characteristics, Pathophysiological Mechanisms, and Potential Prevention Strategies

Frailty has been conceptualized not only as a physical disease, but also as a multidomain entity that encompasses a multimorbid status, disability, cognitive impairment, psychosocial risk factors, and even geriatric syndromes. In addition to physical ailments and depending on the diagnostic model. Standardized neuropsychological tests can identify cognitive deficiencies along with mild cognitive impairment, a pre-dementia stage characterized by memory and/or other cognitive domain impairments with relatively preserved instrumental activities of daily living. Hence, the possibility of cognitive frailty (CF), a construct that refers to physical frailty in concurrence with non-dementia cognitive decline, is proposed. The estimated prevalence of CF ranges from 10.3 to 42.8%. It is likely that the pathway to overt cognitive impairment, which does not yet involve physical function, begins with the asymptomatic early accumulation of progressive brain damage. Thus, timely detection strategies that target the initial phases of CF are warranted. The pathophysiological components of CF include dysregulation of the hypothalamic-pituitary axis stress response, imbalance in energy metabolism, impaired cardiovascular function, mitochondrial deterioration, and vascular age-related arterial stiffness. Changes that contribute to this disease can also occur at the cellular level, including overexpression of the renin-angiotensin-aldosterone system, activation of proinflammatory pathways, endothelial dysfunction, reduced nitric oxide production, and increased oxidative stress. Non-pharmacological interventions, that range from dietary and nutritional counseling to psychosocial therapy, are currently the main approaches. Both cognitive and physical training programs are considered to be the best researched and most useful multidomain interventions. Clinicians recognize CF as a valid concept that warrants prevention and treatment strategies supported by current research.

Interactive association of metals and Life's Essential 8 with mortality in U.S. adults: a prospective cohort study from the NHANES dataset

BACKGROUND

Life's Essential 8 (LE8) is a novel assessment of cardiovascular health (CVH) by evaluating lifestyle, and reports of the associations between LE8 and urinary metals on mortality have been very limited. This study aimed to conduct a prospective cohort study and investigate the combined effects of metals and LE8 on mortality in U.S. adults.

METHODS

This study enrolled participants with complete information on urinary metals, LE8, mortality status, and confounders from the National Health and Nutrition Examination Survey (2005-2018). The Cox regression model, adaptive lasso penalized regression, and restricted cubic spline were used to analyze the individual effects of metals and LE8 on all-cause mortality. The additive and multiplicative interaction scales and quantile g-computation were used to evaluate the interaction and combined effects. Stratified analyses were performed to clarify whether metals and LE8 interacted with other variables to influence all-cause mortality.

RESULTS

A total of 8017 participants were included in this study. The concentrations of cadmium, cobalt, lead, antimony, and thorium were greater in the low CVH group than in the high CVH group [median (µg/L): 0.29 vs. 0.19, 0.36 vs. 0.35, 0.48 vs. 0.39, 0.05 vs. 0.04, and 0.07 vs. 0.06]. The interaction between cadmium and LE8 was statistically significant, with a synergy index of 1.169 (95% CI: 1.004, 1.361). The stratified analyses showed that the interaction between age and LE8 had an impact on all-cause mortality (P for interaction = 0.004).

CONCLUSIONS

In this representative sample of the U.S. population, we found that the combined effect of cadmium, lead, thallium, and LE8 was positively associated with all-cause mortality. Furthermore, the interaction between cadmium and LE8 influenced all-cause mortality. So people should adopt healthy behaviors and reduce heavy metal exposure to minimize the risk of adverse health outcomes.

Joint effect of polysocial risk score, lifestyle and genetic susceptibility with the risk of dementia: A prospective cohort study

OBJECTIVES

The comprehensive impact of polysocial risk score (PsRS)-encompassing multiple social determinants of health (SDoHs) with genetic and lifestyle factors on dementia incidence remains to be elucidated.

STUDY DESIGN

This study aimed to clear the associations between PsRS and dementia incidence and evaluated how genetic and lifestyle factors modified these associations in the UK Biobank cohort.

METHODS

The detailed prospective study involved over 500,000 participants when recruited in 2006-2010. The PsRS was calculated by 12 SDoHs across psychosocial factors, socioeconomic status, and neighborhood and living environment. A healthy lifestyle score was constructed from physical activities, alcohol consumption, smoking status, and diet. A genetic risk score (GRS) was computed via genotype data from UK Biobank. The Cox proportional hazards model was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for the association between PsRS, lifestyle factors, GRS and dementia.

RESULTS

Results showed the participants with intermediate (HR = 1.32, 95%CI: 1.20-1.45) and high PsRS (HR = 2.10, 95 % CI: 1.91-2.32) were significantly associated with an increased risk of dementia compared with those with a low PsRS. Then, compared with participants with low PsRS and favorable lifestyle/low GRS, high PsRS and unfavorable lifestyle/high GRS had the highest risk of dementia (HR = 3.11,95%CI: 2.63-3.68)/(HR = 3.56, 95%CI: 2.62-4.85).

CONCLUSIONS

Both high PsRS and GRS were significantly associated with higher dementia risk. A favorable lifestyle could reduce dementia incidence regardless of high PsRS or GRS. Additionally, focusing on the intervention of SDoHs would be positive in preventing dementia.

Joint Association of Combined Healthy Lifestyle Factors and Hearing Loss With Cognitive Impairment in China

BACKGROUND

Hearing loss and lifestyle factors have been associated with cognitive impairment. We aimed to explore the joint association of combined healthy lifestyle factors and hearing loss with cognitive impairment, which has been scarcely studied.

METHODS

This baseline study used data from the CHOICE-Cohort study (Chinese Hearing Solution for Improvement of Cognition in Elders). Hearing loss was assessed by the better-ear pure-tone average. A composite healthy lifestyle score was built based on never smoking, never drinking, regular physical activity, and a balanced diet. Cognitive impairment was diagnosed by the Mini-Mental State Examination score of less than 24.

RESULTS

We included 17 057 participants aged 60 years or older in China (mean age 69.8 [standard deviation 6.2] years, 55.7% female). Among the participants, 48.3% (n = 8 234) had mild hearing loss, and 25.8% (n = 4 395) had moderate or greater hearing loss. The proportion of participants with healthy lifestyle scores of 0-1, 2, 3, and 4 was 14.9% (n = 2 539), 29.3% (n = 5 000), 37.4% (n = 6 386), and 18.4% (n = 3 132), respectively. About 29.6% (n = 5 057) participants had cognitive impairment. When compared to those with normal hearing and healthy lifestyle (scores of 3-4), participants with hearing loss plus unhealthy lifestyle (scores of 0-2) exhibited approximately twofold increased risk of cognitive impairment (odds ratio [OR] = 1.92, 95% confidence interval [CI] 1.70-2.18). Conversely, the risk was greatly attenuated by adherence to healthy lifestyle in individuals with hearing loss (OR = 1.57, 95% CI 1.40-1.76).

CONCLUSIONS

Our findings demonstrated adherence to a broad range of healthy lifestyle factors was associated with a significantly lower risk of cognitive impairment among participants with hearing loss.

APOE ε4 carrier status moderates the effect of lifestyle factors on cognitive reserve

INTRODUCTION

This study examines the role of lifestyle factors in cognitive reserve among older adults, focusing on the moderating effect of apolipoprotein E (APOE) ε4 status.

METHODS

Data from 157 participants aged 45 and older from the Healthy Brain Initiative (HBI) were analyzed. Cognitive reserve was estimated using residual scores from Cognivue Clarity tests after accounting for brain atrophy and white matter hyperintensities (WMHs). Lifestyle factors included education, occupational attainment, physical activity, social engagement, diet, and mindfulness. Structural equation models were conducted to assess interactions.

RESULTS

Significant interactions were found between APOE ε4 status and mindfulness and social engagement on cognitive reserve, indicating stronger associations for APOE ε4 carriers.

DISCUSSION

APOE ε4 carriers may benefit more from certain lifestyle factors, potentially through stress reduction and anti-inflammatory pathways. These findings support integrating APOE ε4 genetic screening into personalized prevention strategies to enhance interventions aimed at preserving cognitive function and delaying dementia onset in at-risk populations.

HIGHLIGHTS

Mindfulness and social engagement have increased cognitive reserve in APOE ε4 carriers. Study uses residual scores from Cognivue Clarity tests to estimate cognitive reserve. APOE ε4 carriers show stronger associations with certain lifestyle factors on cognitive reserve. Personalized interventions could enhance cognitive resilience in genetically at-risk populations. Comprehensive assessment of multiple lifestyle factors highlights targeted intervention benefits.

Assessment of Wearable Device Adherence for Monitoring Physical Activity in Older Adults: Pilot Cohort Study

Background

Physical activity has emerged as a modifiable behavioral factor to improve cognitive function. However, research on adherence to remote monitoring of physical activity in older adults is limited.

Objective

This study aimed to assess adherence to remote monitoring of physical activity in older adults within a pilot cohort from objective user data, providing insights for the scalability of such monitoring approaches in larger, more comprehensive future studies.

Methods

This study included 22 participants from the Boston University Alzheimer's Disease Research Center Clinical Core. These participants opted into wearing the Verisense watch as part of their everyday routine during 14-day intervals every 3 months. Eighteen continuous physical activity measures were assessed. Adherence was quantified daily and cumulatively across the follow-up period. The coefficient of variation was used as a key metric to assess data consistency across participants over multiple days. Day-to-day variability was estimated by calculating intraclass correlation coefficients using a 2-way random-effects model for the baseline, second, and third days.

Results

Adherence to the study on a daily basis outperformed cumulative adherence levels. The median proportion of adherence days (wearing time surpassed 90% of the day) stood at 92.1%, with an IQR spanning from 86.9% to 98.4%. However, at the cumulative level, 32% (7/22) of participants in this study exhibited lower adherence, with the device worn on fewer than 4 days within the requested initial 14-day period. Five physical activity measures have high variability for some participants. Consistent activity data for 4 physical activity measures might be attainable with just a 3-day period of device use.

Conclusions

This study revealed that while older adults generally showed high daily adherence to the wearable device, consistent usage across consecutive days proved difficult. These findings underline the effectiveness of wearables in monitoring physical activity in older populations and emphasize the ongoing necessity to simplify usage protocols and enhance user engagement to guarantee the collection of precise and comprehensive data.

Exploring the link between sedentary behavior and cognitive decline: a comprehensive study combining Mendelian randomization and animal model experiments

Objective

The causal link between detrimental behaviors and cognitive performance remains unclear. This research seeks to investigate the causal impact of adjustable lifestyle factors on cognitive deterioration, including frequency of alcohol intake, onset of smoking, and sedentary activities like prolonged television viewing.

Methods

This research combines large-scale genetic data obtained from univariable and multivariable Mendelian randomization analyses with experimental findings obtained from animal models.

Results

Our findings reveal that the odds ratio (OR) for cognitive function deterioration was 0.445 (inverse variance weighted [IVW] 95% CI: 0.370 to 0.536, p < 0.001) for each standard deviation increase in television watching time. After adjustment for body mass index (BMI), number of days walked /moderate activity over 10+ min and education in Multivariable Mendelian Randomization (MVMR), only the genetic predisposition to increased television watching time remained significantly associated with worse cognitive function (OR 0.659, 95% CI: 0.452 to 0.960, p = 0.030). The other two habits had no significant effects. Sensitivity analyses have confirmed that genetic pleiotropy did not influence the results. To further explore the relationship between sedentary behavior and cognitive function, as well as the underlying mechanisms, we conducted a restricted cage housing experiment and a physical exercise training experiment in mice. The results showed that physical exercise significantly improved spatial memory, as assessed by the Morris water maze, and increased exploratory interest, as evaluated by the open field test (OFT) and the elevated plus-maze test, compared to the sedentary control group. These cognitive advantages may be mediated through mechanisms involving free radical scavenging and enhanced synaptic plasticity.

Conclusion

Our research provides genetic evidence indicating that extended television viewing is linked to an elevated risk of cognitive decline. Additionally, experimental data from mouse models suggest that physical exercise can counteract cognitive decline and anxiety-like behaviors induced by sedentary behavior. This protective effect is likely mediated by reactive oxygen species (ROS)-dependent mechanisms that enhance synaptic plasticity within the hippocampus.

Mediterranean Diet and Lifestyle in Persons with Mild to Moderate Alzheimer's Disease

Due to the continuous aging of the population and consequent increase in dementia, focus on its prevention is of growing importance for public health. Since effective pharmacological treatments are not yet available, other determinants of cognitive decline have become fundamental. Several studies have indicated that the Mediterranean diet (MedDiet) is associated with reduced incident cognitive decline and dementia, but few studies have been conducted in persons already diagnosed with Alzheimer's disease (AD). We age-matched 73 patients with mild-moderate AD with 73 controls (mean age for the whole group = 76.5 ± 6.5; 67.5% women). The cases had a significantly lower adherence to the MedDiet and lower physical activity vs. controls, where only one participant (1.4%) had a high adherence to the MedDiet among cases compared to 5.5% among controls, while 52.5% of the cases had a moderate adherence to the MedDiet vs. 82.2% in controls. In multivariate analysis, only the presence of AD was significantly associated with a lower adherence to the MedDiet vs. controls. Other factors examined (gender, age, physical activity level, multimorbidity, and polypharmacy) were not significantly associated with adherence to the MedDiet. Thus, AD patients had a low adherence to the MedDiet and very low physical activity. Public health strategies aimed at promoting the Mediterranean diet and physical activity for older people should be a priority.

The Hidden Dangers of Sedentary Living: Insights into Molecular, Cellular, and Systemic Mechanisms

With the aging of the global population, neurodegenerative diseases are emerging as a major public health issue. The adoption of a less sedentary lifestyle has been shown to have a beneficial effect on cognitive decline, but the molecular mechanisms responsible are less clear. Here we provide a detailed analysis of the complex molecular, cellular, and systemic mechanisms underlying age-related cognitive decline and how lifestyle choices influence these processes. A review of the evidence from animal models, human studies, and postmortem analyses emphasizes the importance of integrating physical exercise with cognitive, multisensory, and motor stimulation as part of a multifaceted approach to mitigating cognitive decline. We highlight the potential of these non-pharmacological interventions to address key aging hallmarks, such as genomic instability, telomere attrition, and neuroinflammation, and underscore the need for comprehensive and personalized strategies to promote cognitive resilience and healthy aging.

Genomic Insights into Dementia: Precision Medicine and the Impact of Gene-Environment Interaction

The diagnosis, treatment, and management of dementia provide significant challenges due to its chronic cognitive impairment. The complexity of this condition is further highlighted by the impact of gene-environment interactions. A recent strategy combines advanced genomics and precision medicine methods to explore the complex genetic foundations of dementia. Utilizing the most recent research in the field of neurogenetics, the importance of precise genetic data in explaining the variation seen in dementia patients can be investigated. Gene-environment interactions are important because they influence genetic susceptibilities and aid in the development and progression of dementia. Modified to each patient's genetic profile, precision medicine has the potential to detect groups at risk and make previously unheard-of predictions about the course of diseases. Precision medicine techniques have the potential to completely transform treatment and diagnosis methods. Targeted medications that target genetic abnormalities will probably appear, providing the possibility for more efficient and customized medical interventions. Investigating the relationship between genes and the environment may lead to preventive measures that would enable people to change their surroundings and minimize the risk of dementia, leading to the improved lifestyle of affected people. This paper provides a comprehensive overview of the genomic insights into dementia, emphasizing the pivotal role of precision medicine, and gene-environment interactions.

Informal caregiver and healthcare professional perspectives on dementia and nutrition

BACKGROUND

Persons living with dementia and informal caregivers are at a higher risk for malnutrition. Most caregivers are not experts at identifying nutritional complications of dementia. Therefore, we aimed to identify nutrition knowledge and challenges related to feeding and caring for persons with dementia to develop a meaningful intervention.

METHODS

A mixed-methods approach was used. Eight focus groups were conducted with caregivers of persons living with dementia (n = 28) and healthcare professionals (n = 23). Data was analysed using NVivo software. A questionnaire was administered to identify nutritional challenges. A modified food frequency questionnaire assessed food patterns of caregivers and persons with dementia. Results were compared to Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) dietary guidelines. Data were analysed using SPSS software.

RESULTS

Four major themes emerged: forgetting to eat, developing food aversions, strong preferences for sweets and weight changes. Findings revealed common strategies used to improve nutrition intake included cueing, supplements and quiet eating environment. Caregivers were impacted by stress leading to poorer food choices and exhaustion. Recommendations for a caregiver program made by participants included education, resources and support. Findings from the food frequencies questionnaire survey showed most participants had a lower dietary diversity compared to the MIND diet guidelines.

CONCLUSIONS

With both groups being more prone to malnutrition, this research shows that participants were less likely to obtain adequate nutrition for brain health. Additionally, caregivers are dealing with nutrition issues themselves and their person living with dementia. The findings support the need for registered dietitians to provide tailored nutrition interventions for these families.

Associations between the Number of Children, Depressive Symptoms, and Cognition in Middle-Aged and Older Adults: Evidence from the China Health and Retirement Longitudinal Study

Background: China's rapidly aging population presents challenges for cognitive health and mental well-being among the older adults. This study examines how the number of children affects cognitive function in middle-aged and older adults and whether depressive symptoms mediate this relationship. Methods: This study analyzed data from waves 1 to 5 (2011-2020) of the China Health and Retirement Longitudinal Study (CHARLS), involving 5932 participants aged 45 and older. Participants were grouped by the number of children: childless, only child and multiple children. We used Logarithmic Generalized Linear Models (LGLMs) to explore the relationships among the number of children, depressive symptoms, and cognitive function. Indirect effect coefficients and 95% bias-corrected and accelerated confidence intervals (BCaCI) were estimated using Simultaneous Equation Models (SEM) with three-stage least squares (3SLS) and the bootstrap method to assess the mediating effect of depressive symptoms. Results: In middle-aged and older adults, a negative association was observed between the number of children and overall cognitive functioning (all p < 0.01). This association remained significant even after adjusting for covariates in groups with three (β = -0.023, p < 0.05) and four or more children (β = -0.043, p < 0.001). Conversely, the positive association between the number of children and depression also persisted after adjusting for covariates, although it weakened as the number of children increased (all p < 0.01). Depressive symptoms consistently correlated negatively with overall cognitive function (p < 0.001) and partially mediated the relationship between the number of children and cognitive function (pMe = 20.36%, p < 0.05). The proportion of the mediating effect attributed to depression was more pronounced in middle-aged and older adults who had experienced the loss of children (pMe = 24.31%) or had two children (pMe = 25.39%), with stronger mediating effects observed in males (pMe = 48.84%) and urban residents (pMe = 64.58%). Conclusions: The findings indicate that depressive symptoms partially mediate the relationship between the number of children and cognitive function in middle-aged and older adults in China. These results highlight the significance of considering mental health factors when studying cognitive function in this demographic. Notably, in families without children and those with two children, depressive symptoms play a crucial role in explaining the decline in cognitive function.

Dose-response relationship of high-intensity training on global cognition in older adults with mild cognitive impairment or dementia: a systematic review with meta-analysis - the ACHIEVE-Study

BACKGROUND

The prevalence of mild cognitive impairment (MCI) and its subsequent progression to dementia has increased progression to dementia has increased worldwide, making it a topic of interest. of interest, and it has been observed that approximately 23% of cases are avoidable through preventable through vigorous exercise.

METHODS

A systematic review with meta-analysis was conducted by searching in the PubMed, Scopus, CINAHL, and Web of Science databases. For inclusion, studies had to incorporate High Intensity Training (HIT) as a primary or significant component of the overall intervention for older adults with MCI. Out of the 611 articles identified, 14 randomized clinical trials met the criteria for inclusion in the review.

RESULTS

Fourteen trials were included in the systematic review, and seven were included in the meta-analysis. A total of 1839 participants were included in the studies, with 1014 receiving a high-intensity training-based intervention, and 998 were considered in the meta-analysis. Compared to usual care or sedentary activities, the high-intensity training interventions had a positive effect on cognition, either improving it or delaying the decline (g = 0.710 (95% CI: 0.191 - 1.229; p = 0.007). Additionally, the meta-analysis determined that a frequency of 3 sessions per week (g = 0.964, CI = 0.091 - 1.837, p = 0.030) of approximately 60 minutes (g = 0.756, CI = 0.052 - 1.460, p = 0.035) each was the best dose to obtain better effects on global cognition.

CONCLUSION

Low-frequency and short-duration high-intensity training interventions are sufficient to improve or at least delay the decline in global cognition.

The relationship between multimorbidity and cognitive function in older Chinese adults: based on propensity score matching

Objective

The goal of this study was to further validate the effect of multimorbidity on cognitive performance in older adults after controlling for confounders using propensity score matching (PSM).

Methods

A cross-sectional survey of older adult people aged 60 years or older selected by convenience sampling was conducted in seven medical institutions, three communities, and five nursing homes in Zunyi City, Guizhou Province. The data collected included general information, health-related information, and Mini-Mental State Examination (MMSE) scores. Variables were controlled for confounders by PSM to analyze differences in cognitive ability between multimorbidity and nonmultimorbidity older adults. Logistic regression and multivariate-adjusted restricted cubic spline (RCS) curves for matched samples were used to assess the relationship between multimorbidity and cognitive decline.

Results

A total of 14,175 respondents were enrolled, and the mean age of the participants included in this study was 71.26 ± 7.1 years, including 7,170 (50. 58%) of the participants were males, 7,005 (49.42%) were females, and 5,482 participants (38.67%) were screened for cognitive decline. After PSM, logistic regression analysis revealed that multimorbidity was a risk factor for cognitive decline (OR = 1.392, 95% CI = 1.271-1.525, p < 0.001). The RCS show that the risk of cognitive decline is always greater in older adults with multimorbidity than in older adults without multimorbidity at the same age. Age, sex, marital status, educational level, monthly income, drinking status, participation in social activities, and exercise were influential factors for cognitive decline in older adults (p < 0.05). The incidence of cognitive decline in older adults with multimorbidity was also greater than that in older adults with one chronic disease (p < 0.001).

Conclusion

The risk of cognitive decline in older adults with multimorbidity is greater than that in older adults without multimorbidity; therefore, the government should strengthen the prevention and treatment of multimorbidity in older adults to further protect their cognitive abilities.

Focusing attention on the important association between food insecurity and psychological distress: a systematic review and meta-analysis

BACKGROUND

Food insecurity has involved more than 750 million individuals worldwide. The association of food insecurity with socio-economic factors is also undeniable demand more consideration. Food insecurity will become a global priority by 2030. This systematic review and meta-analysis examined current literature concerning the association between food insecurity and psychological distress.

METHODS

Relevant researches were identified by searching databases including PubMed, EMBASE, Scopus, and Web of Science, ProQuest, and Cochrane Library up to June 2024 without language limitation. Then a snowball search was conducted in the eligible studies. The quality assessment was made through Newcastle-Ottawa Scale.

RESULTS

Data were available from 44 cross-sectional articles for systematic review and 17 eligible articles for meta-analysis with 2,267,012 and 1,953,636 participants, respectively. Findings support the growing segment of literature on the association between food insecurity and psychological distress. The highly represented groups were households with low income. Psychological and diabetic distress was directly associated with food insecurity as it increased the odds of distress to 329% (OR: 3.29; 95% CI: 2.46-4.40). Sleep problems, anxiety, depression, lower life satisfaction, obesity, and a higher rate of smoking were among the secondary outcomes.

CONCLUSION

Food insecurity was a common stressor that can have a negative impact on psychological well-being and even physical health. The findings should be considered in the public health and making policy-making process.

Dissecting the causal relationship between moderate to vigorous physical activity levels and cognitive performance: a bidirectional two-sample Mendelian randomization study

Introduction

Recent studies increasingly suggest that moderate-to-vigorous physical activity (MVPA) impacts cognitive risk. However, the bidirectional nature of this relationship warrants further exploration. To address this, we employed a Mendelian randomization (MR) approach, analyzing two distinct samples.

Methods

These analyses utilized published genome-wide association study (GWAS) summary statistics for MVPA (n = 377,234) and cognitive performance (n = 257,841). Our primary method was the inverse variance weighted (IVW) model with random effects, aiming to deduce potential causal links. Additionally, we employed supplementary methods, including MR Egger regression, Weighted median, Weighted mode, and Simple mode. For sensitivity analysis, tools like the MR Egger test, Cochran's Q, MR PRESSO, and leave-one-out (LOO) were utilized.

Results

Our findings indicate a decrease in cognitive risk with increased MVPA (Odds Ratio [OR] = 0.577, 95% Confidence Interval [CI]: 0.460-0.723, p = 1.930 × 10-6). Furthermore, enhanced cognitive levels corresponded to a reduced risk of inadequate MVPA (OR = 0.866, 95% CI: 0.839-0.895, p = 1.200 × 10-18).

Discussion

In summary, our study demonstrates that MVPA lowers cognitive risk, while poor cognitive health may impede participation in MVPA. Overall, these findings provide valuable insights for developing personalized prevention and intervention strategies in health and sports sciences.

Poor sleep quality, dementia status and their association with all-cause mortality among older US adults

BACKGROUND

Evidence points to associations between sleep quality, dementia, and mortality. We examined whether poor sleep quality mediated or moderated the association between dementia and mortality risk among older US adults and vice versa, and whether these associations differed by sex and by race.

METHODS

The study investigated bi-directional associations between sleep quality, dementia and mortality in older US adults using data from the Health and Retirement Study (N = 6,991, mean age = 78.1y, follow-up: 2006-2020, number of deaths = 4,938). It tested interactions and mediating effects, using Cox proportional hazards models and four-way decomposition models.

RESULTS

Poor sleep quality was associated with increased mortality risk, particularly among male and White older adults. However, the association was reversed in the fully adjusted model, with a 7% decrease in risk per tertile. Probable dementia was associated with a two-fold increase in mortality risk, with a stronger association found among White adults. The association was markedly attenuated in the fully adjusted models. Sleep quality-stratified models showed a stronger positive association between dementia and mortality among individuals with better sleep quality. Both mediation and interaction were involved in explaining the total effects under study, though statistically significant total effects were mainly composed of controlled direct effects.

CONCLUSIONS

Poor sleep quality is directly related to mortality risk before lifestyle and health-related factors are adjusted. Dementia is linked to mortality risk, especially in individuals with better sleep quality, males, and White older adults. Future research should explore the underlying mechanisms.

Glutamatergic Neurotransmission in Aging and Neurodegenerative Diseases: A Potential Target to Improve Cognitive Impairment in Aging

Aging is characterized by the decline in many of the individual's capabilities. It has been recognized that the brain undergoes structural and functional changes during aging that are occasionally associated with the development of neurodegenerative diseases. In this sense, altered glutamatergic neurotransmission, which involves the release, binding, reuptake, and degradation of glutamate (Glu) in the brain, has been widely studied in physiological and pathophysiological aging. In particular, changes in glutamatergic neurotransmission are exacerbated during neurodegenerative diseases and are associated with cognitive impairment, characterized by difficulties in memory, learning, concentration, and decision-making. Thus, in the present manuscript, we aim to highlight the relevance of glutamatergic neurotransmission during cognitive impairment to develop novel strategies to prevent, ameliorate, or delay cognitive decline. To achieve this goal, we provide a comprehensive review of the changes reported in glutamatergic neurotransmission components, such as Glu transporters and receptors during physiological aging and in the most studied neurodegenerative diseases. Finally, we describe the current therapeutic strategies developed to target glutamatergic neurotransmission.

Efficacy of technology-based cognitive and exercise interventions for mild cognitive impairment: A systematic review, network meta-analysis, and meta-regression of randomized controlled trials

BACKGROUND

Technology has been increasingly integrated into controlling the decline of cognitive function. It is unclear whether technology-based cognitive and exercise interventions (T-CEIs) could generate synergistic benefits and what components would optimize this effect. This study aimed to compare the effectiveness of various T-CEIs on cognitive function in individuals with mild cognitive impairment (MCI).

METHODS

In this study, we searched MEDLINE, Web of Science, Scopus, Embase, and APA PsycInfo from inception to November 4, 2023. We included randomized controlled trials that evaluated the effects of T-CEIs on cognitive function for individuals with MCI. The primary outcome was global cognition. The outcomes were summarized in narrative synthesis and combined using meta-analysis. Pairwise meta-analysis and network meta-analysis were sequentially performed to investigate the effects of each category of interventions and their comparative intervention effectiveness, respectively. Meta-regression was performed to examine the influence of study design and participants' characteristics on the intervention effectiveness. This systematic review protocol was registered in PROSPERO (CRD 42023486359).

RESULTS

Twenty-eight studies with 1633 participants were included. The results of pairwise meta-analyses indicated that T-CEIs were superior to active/passive controls in improving global cognition, cognitive shifting, processing speed, working memory, delayed recall, and category fluency (p < 0.05). The results of network meta-analyses indicated that the optimal components in improving global cognition (SUCRA 77.0 %, SMD 0.85, 95 % CI -0.17 to 1.87) and cognitive shifting (SUCRA 92.4 %, SMD 1.57, 95 % CI 0.88-2.25) were cognitive stimulation (CS) combined with mind-body exercise (MBE), while cognitive training combined with MBE was the most beneficial in developing processing speed (SUCRA 88.5 %, SMD 0.68, 95 % CI 0.14-1.22). Meta-regression further suggested that the effects of the tested interventions were independent of the various factors related to study design and participants' characteristics.

CONCLUSIONS

T-CEIs are effective in improving global cognition and core subdomains of cognition in individuals with MCI. This review highlights the superior effects of technology-based CS combined with MBE in improving global cognition.

Aerobic Exercise Ameliorates Cognitive Disorder and Declined Oxidative Stress via Modulating the Nrf2 Signaling Pathway in D-galactose Induced Aging Mouse Model

The aim of this research was to explore the potential of treadmill exercise in preventing brain aging and neurodegenerative diseases caused by oxidative stress, by studying its effects on D-galactose-induced mice and the mechanisms involved. The results showed that C57BL/6 mice induced with D-gal exhibited cognitive impairment and oxidative stress damage, which was ameliorated by treadmill exercise. The Morris water maze also showed that exercise improved cognitive performance in aging mice and alleviated hippocampal and mitochondrial damage. The study also found that treadmill exercise increased the expression of nuclear factor Nrf2, p-GSK3β, HO-1, NQO1, BDNF, and Bcl-2 proteins while decreasing the expression of Bax. Furthermore, there was a substantial increase in the levels of CAT, GSH-PX and SOD in the serum, along with a decrease in MDA levels. The outcomes propose that aerobic exercise has the potential to hinder oxidative stress and cell death in mitochondria through the modulation of the Nrf2/GSK3β signaling pathway, thus improving cognitive impairment observed in the aging model induced by D-galactose. It appears that treadmill exercise could potentially serve as an effective therapeutic approach to mitigating brain aging and neurodegenerative diseases triggered by oxidative stress.

What exercise strategies are best for people with cognitive impairment and dementia? A systematic review and meta-analysis

OBJECTIVE

Explore the types of exercise that are appropriate for people with dementia, as well as the intensity and frequency of exercise training that is appropriate for older patients to carry out.

METHODS

Cochrane Library, PubMed, Embase, Web of Science, Scopus databases were searched by computer to collect RCT studies that met the inclusion criteria of this article. The search time limit was until January 2024. Two reviewers independently screened literature, extracted data, and assessed the quality and risk of bias of the included studies. Then, meta-analysis was performed using RevMan 5.4 and Stata 15.1 software.

RESULTS

The results of our study showed that physical exercise improved patients' cognitive ability and walking ability, with aerobic and multicomponent training showing the best improvement, and that the number of training sessions should not be too high, with the experimental group showing the best results when the total number of interventions was less than 30.

CONCLUSION

We recommend long-term exercise training for middle-aged and elderly patients with dementia or those who are predisposed to dementia. The type of training we recommend is multi-component training and aerobic training, and we recommend 2-3 sessions of exercise per week for about 60 min each.

Aging and cognitive resilience: Molecular mechanisms as new potential therapeutic targets

As the global population ages, the need to prolong lifespan and healthspan becomes increasingly imperative. Understanding the molecular determinants underlying cognitive resilience, together with changes during aging and the (epi)genetic factors that predispose an individual to decreased cognitive resilience, open avenues for researching novel therapies. This review provides a critical and timely appraisal of the molecular mechanisms underlying cognitive resilience, framed within a critical analysis of emerging therapeutic strategies to mitigate age-related cognitive decline. Significant insights from both animals and human subjects are discussed herein, directed either toward active pharmaceutical ingredients (drug repositioning or macromolecules), or, alternatively, advanced cellular therapies.

Non-Linear Association of Dietary Polyamines with the Risk of Incident Dementia: Results from Population-Based Cohort of the UK Biobank

Natural polyamines, including spermidine (SPD), spermine (SPM) and putrescine (PUT), are evolutionarily conserved endogenous molecules crucially involved in central cellular processes. Their physiological importance may extend to the maintenance of cognitive function during aging. However, limited population-based epidemiological studies have explored the link between dietary polyamines and dementia risk. This study was a prospective analysis of 77,092 UK Biobank participants aged ≥ 60 years without dementia at baseline. We used Cox proportional hazard regression models to explore the associations between dietary polyamines and the risk of dementia, and restricted cubic splines to test the non-linear relationships. During a median follow-up of 12 years, 1087 incidents of all-cause dementia cases occurred, including 450 Alzheimer's disease (AD) cases and 206 vascular dementia (VD) cases. The fully adjusted hazard ratios (HRs) for the upper fourth quintile of dietary SPD, in comparison with the lowest quintile of intake, were 0.68 (95% confidence interval [95% CI]: 0.66-0.83) for the risk of all-cause dementia, 0.62 (95% CI: 0.45-0.85) for AD and 0.56 (95% CI: 0.36-0.88) for VD, respectively. A 26% reduction in dementia risk [HR: 0.74, (95% CI: 0.61-0.89)] and a 47% reduction in AD [HR: 0.53, (95%CI: 0.39-0.72)] were observed comparing the third with the lowest quintiles of dietary SPM. Dietary PUT was only associated with a reduced risk of all-cause dementia in the fourth quintile [HR (95% CI): 0.82 (0.68-0.99)]. Reduced risk was not found to be significant across all quintiles. There were 'U'-shaped relationships found between dietary polyamines and all-cause dementia, AD and VD. Stratification by genetic predisposition showed no significant effect modification. Optimal intake of polyamines was linked to a decreased risk of dementia, with no modification by genetic risk. This potentially suggests cognitive benefits of dietary natural polyamines in humans.

Risk factors for cognitive decline in non-demented elders with amyloid-beta positivity

BACKGROUND

As a currently incurable but preventable disease, the prevention and early diagnosis of Alzheimer's disease (AD) has long been a research hotspot. Amyloid deposition has been shown to be a major pathological feature of AD. Notably, not all the people with amyloid-beta (Aβ) pathology will have significant cognitive declines and eventually develop AD. Therefore, the aim of this study was to explore the risk factors for cognitive decline in Aβ-positive participants.

METHODS

We included 650 non-demented participants who were Aβ-positive at baseline from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Mixed effects and COX regression models were applied to assess 37 potential risk factors. Mixed effects models were employed to assess the temporal associations between potential risk factors and four cognitive assessment scales. COX regression models were used to assess the impact of potential risk factors on cognitive diagnosis conversion. Univariate and multivariate analyses were applied to the above models. Additionally, we used the Cochran-Armitage trend test to examine whether the incidence of cognitive decline increased with the number concurrent of risk factors.

RESULTS

Six factors (low diastolic pressure, low body mass index, retired status, a history of drug abuse, Parkinsonism, and depression) were the identified risk factors and four factors (a history of urinary disease, musculoskeletal diseases, no major surgical history, and no prior dermatologic-connective tissue diseases) were found to be suggestive risk factors. The incidence of cognitive decline in the Aβ-positive participants gradually increased as the number of concurrent risk factors increased (p for trend = 0.0005).

CONCLUSIONS

Our study may facilitate the understanding of the potential pathological processes in AD and provide novel targets for the prevention of cognitive decline among participants with Aβ positivity.

Healthy Dietary Pattern Improves Cognitive Function in Elderly Persons With Periodontitis: A Cross-Sectional Study of NHANES

AIM

Cognitive decline is thought to be more prevalent in elderly persons with periodontitis. Greater adherence to Healthy Eating Index (HEI)-2015 has been reported to improve cognitive function in the elderly population. However, whether the benefits of HEI-2015 on cognitive function apply to elderly patients with periodontitis remains unknown.

METHODS

This is a cross-sectional study based on the National Health and Nutrition Examination Survey (NHANES). The data were extracted from database 2011-2014. Cognitive function was measured through the Consortium to Establish a Registry for Alzheimer's Disease battery for immediate recall (CERAD-WL) and delayed recall (CERAD-DR), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). The data of HEI-2015 were acquired from 24-hour dietary recalls. Weighted linear regression models were performed to investigate the association between HEI-2015 and cognitive function in elderly patients with periodontitis. The associations were further investigated in subgroups of sex, cardiovascular disease status, and depression status.

RESULTS

A total of 1862 participants were included, and 1223 of them had periodontitis. Periodontitis was negatively associated with cognitive function (β = -0.45; 95% confidence interval [CI], -0.87 to -0.03). No statistically significant relationship was observed between HEI-2015 and cognitive function (β = 0.33; 95% CI, -0.02 to 0.69). Low HEI-2015 score was associated with high odds of cognitive decline in patients with periodontitis (β = -0.73; 95% CI, -1.25 to -0.21; P for trend = .01). Higher HEI-2015 was related to the lower incidence of cognitive function decline in patients with periodontitis who were female (β = -0.53; 95% CI, -1.03 to -0.03), had a socioeconomic status from 0 to 3 (β = -0.55; 95% CI, -1.00 to -0.09), did not have cardiovascular disease (β = -0.60; 95% CI, -1.14 to -0.05), and did not have depression (β = -0.57; 95% CI, -1.11 to -0.03).

CONCLUSIONS

Greater HEI-2015 adherence may improve cognitive function amongst elderly patients with periodontitis. Further studies are needed to investigate this putative association in elderly persons with periodontitis.

Long-Term Effects of the Multicomponent Program BrainProtect® on Cognitive Function: One-Year Follow-Up in Healthy Adults

Background

Age-related neuronal changes impact cognitive integrity, which is a major contributor to health and quality of life. The best strategy to prevent cognitive decline and Alzheimer's disease is still debated.

Objective

To investigate the long-term effects of the eight-week multicomponent training program BrainProtect® on cognitive abilities compared to general health counseling (GHC) in cognitively healthy adults in Germany.

Methods

Healthy adults (age ≥50 years) previously randomized to either GHC (n = 72) or BrainProtect (intervention group, IG, n = 60) for eight-weeks (once weekly, 90 minutes, group-based) underwent a comprehensive neuropsychological test battery and health-related quality of life (HRQoL) evaluation 3- and 12-months after intervention end.

Results

Dropout rates were n = 8 after 3 months and n = 19 after 12 months. No significant long-term effect of BrainProtect was observed for the primary endpoint Consortium to Establish a Registry for Alzheimer's Disease (CERAD-Plus) total score. Logical reasoning was significantly improved (p = 0.024) 12 months after completion of the training program in IG participants compared to the GHC group independent of sex, age, education, diet, and physical activity. In IG participants, thinking flexibility (p = 0.019) and confrontational naming (p = 0.010) were improved 3 months after completing the intervention compared to the GHC group, however, after conservative Bonferroni adjustment, significance was lost.

Conclusions

BrainProtect® independently improved logical reasoning compared to GHC up to 12 months after cognitive training's end in healthy adults. To uncover the long-term clinical significance of multicomponent cognitive training in healthy adults, studies with larger sample size and frequent follow up visits are necessary.

Influence of daily life and health profile in subtle cognitive decline of women residing in Spanish religious communities: DeCo religious orders study

Background

Prior to the onset of dementia, individuals commonly undergo a phase marked by subtle cognitive changes, known as subtle cognitive decline. Recognizing these early cognitive alterations is crucial, as they can serve as indicators of an impending decline in cognitive function, warranting timely intervention and support.

Objectives

To determine the incidence of subtle cognitive decline in a population of Spanish women and establish the relationship with possible protective and/or risk factors such as cognitive reserve, cardiovascular risk factors, medication consumption and psychosocial factors.

Design and participants

This is a cross-sectional observational study with women from the general population and a more homogeneous population composed of nuns from the Valencian region (Spain).

Measurements

A validated questionnaire was used including lifestyle variables, chronic illnesses, level of education and pharmacological treatments. Three validated subtle cognitive decline screening tests with varying levels of sensitivity and specificity were used: Memory Impairment Screening, Pfeiffer's Short Portable Mental State Questionnaire, and Semantic Verbal Fluency.

Results

Our results suggest that nuns may have a significantly reduced risk of cognitive decline compared to the general population (20.67% in nuns vs. 36.63% in the general population). This lower risk for subtle cognitive decline in nuns may be partly attributed to their higher cognitive reserve and long-time engagement in intellectually stimulating activities. Additionally, nuns tend to adopt healthy lifestyles, they are not isolated because they live in community and obtained lower scores for risk factors such as depression, anticholinergic burden, and benzodiazepine consumption.

Conclusion

A healthy lifestyle combined with intellectually stimulating activities is related with preserved cognitive function.

Effect of combined physical-cognitive training on the functional and cognitive capacity of older people with mild cognitive impairment: a randomized controlled trial

BACKGROUND

The increase in population aging highlights the growing prevalence of mild cognitive impairment, prompting the adoption of interventions that combine physical exercise and cognitive training to improve health and cognitive performance in older adults. The aim of this study was to analyze the efficacy of a combined program on physical and cognitive health in older people with cognitive impairment.

METHODS

A 12-week randomized controlled clinical trial involving 95 participants (aged 72.12 ± 4.25 years), 47 individuals participated in a control group (CG) that only underwent cognitive stimulation, while 48 individuals were in an experimental group (EG) that participated in a combined program. Balance was measured using the Tinetti scale, upper body strength was assessed with the arm curl test, lower body strength was evaluated with the 30-s chair stand test, flexibility was tested using the back scratch test and chair sit-and-reach test, physical function was measured with the Timed Up and Go test, cognitive function was assessed using the Mini Mental State Examination, cognitive impairment was evaluated with the Montreal Cognitive Assessment, verbal fluency was tested with the Isaac test, and executive functions were assessed using the Trail Making Test.

RESULTS

The results of the study show significant improvements in both physical and cognitive aspects, such as balance, gait, upper and lower body strength, flexibility, physical function, cognitive function, cognitive impairment, verbal fluency, and executive functions in the group that carried out the intervention compared to the control group.

CONCLUSION

A combined program for older individuals with mild cognitive impairment leads to enhancements in physical and cognitive health. These improvements underscore the importance of integrating physical exercise with cognitive training as an effective strategy for enhancing overall health and quality of life in older adults.

TRIAL REGISTRATION

NCT05503641.

Impact of food insecurity on cognitive health in older adults: insights from the NHANES 2011-2014 data

Purpose

To investigate the relationship between food insecurity and cognitive decline among elderly Americans.

Methods

Utilizing NHANES 2011-2014 data, we examined cognitive function via the Immediate Recall Test (IRT), Delayed Recall Test (DRT), Animal Fluency Test (AFT), Digit Symbol Substitution Test (DSST) and assessed food security through the US Food Security Survey Module. Multiple regression models were used to adjust for demographic and health variables.

Results

Food insecurity demonstrated a significant association with lower cognitive function scores. The effects of food insecurity on cognitive function were moderated by factors such as smoking and alcohol use, indicating a direct influence of food insecurity on cognitive decline.

Conclusion

This study underscores the importance of food security for cognitive health in the elderly and advocates for targeted interventions to address nutritional disparities and enhance cognitive functioning in aging populations.

Effect of time-restricted eating and intermittent fasting on cognitive function and mental health in older adults: A systematic review

Objective

Emerging evidence suggests that dietary interventions hold promise for promoting cognitive function and mental well-being in aging populations. This systematic review aimed to examine the potential relationship between Time-Restricted Eating (TRE) and Intermittent Fasting (IFA) with cognitive function and mental health in older adults.

Methods

A thorough exploration was undertaken on electronic databases such as PubMed, Scopus, Web of Science, Science Direct, and Google Scholar, up to October 2023, following PRISMA standards. The evaluation of the quality and potential bias in the incorporated articles involved the use of the Newcastle-Ottawa Scale and Consolidated Standards of Reporting Trials (CONSORT).

Results

From a total of 539 articles initially identified, eight studies met the eligibility criteria for inclusion in this review. Out of these eight studies, six focused on cognitive function, and 2 focused on mental health. The reviewed articles encompassed a wide range of population sizes, with the number of older adults studied varying from 10 to 1357, reflecting a diverse cohort of individuals. Conclusions.The findings suggest that TRE and IFA may have a positive impact on cognitive function and mental health in this population. However, additional research is needed to fully comprehend this relationship. Therefore, future research should specifically examine factors such as the duration and timing of the eating window in TRE, as well as the physical condition of older adults, to provide a more nuanced understanding of the cognitive and mental health benefits of TRE and IFA in older adults.

Prevalence and risk factors for dementia and mild cognitive impairment among older people in Southeast China: a community-based study

BACKGROUND

With the aging population, the number of individuals with dementia in China is increasing rapidly. This community-based study aimed to investigate the prevalence and risk factors for dementia and mild cognitive impairment (MCI) among older adults in China.

METHODS

In this study, 20,070 individuals aged ≥ 65 were recruited between January 1, 2022, and February 1, 2023, from ten communities in Xiamen City, China. We collected data on age, sex, level of education, and medical history, as well as global cognition and functional status. The prevalence of dementia and MCI was examined, and the risk factors for different groups were assessed.

RESULTS

The overall prevalence of dementia and MCI was approximately 5.4% (95% confidence interval [CI], 5.1-5.7) and 7.7% (95% CI, 7.4-8.1), respectively. The results also indicated that dementia and MCI share similar risk factors, including older age, female sex, hypertension, and diabetes mellitus. Compared with individuals with no formal education, those with > 6 years of education had an odds ratio for MCI of 1.83 (95% CI, 1.49-2.25). We also found that only 5.5% of the positive participants chose to be referred to the hospital for further diagnosis and treatment during follow-up visits.

CONCLUSIONS

This study estimated the prevalence and risk factors for dementia and MCI among individuals aged ≥ 65 years in Southeast China. These findings are crucial for preventing and managing dementia and MCI in China.

Comprehensive Bio-Screening of Phytochemistry and Biological Capacity of Oregano (Origanum vulgare) and Salvia triloba Extracts against Oral Cariogenic and Food-Origin Pathogenic Bacteria

This study utilized phytochemical screening to conduct the qualitative analysis of plant extracts, aiming to identify various classes of secondary metabolites. Moreover, the antibacterial activity of different types of Oregano vulgare and Salvia triloba extracts was determined. To achieve the aim of this study, aqueous, ethanolic, and enzymatic extracts were prepared and screened for phytochemical capacity and antioxidant activities. The determination of the antibacterial activity included phenotypic screening of antibiotic susceptibility pattern of oral and food pathogenic bacterial strains, determination of the minimum inhibitory concentration and minimum bactericidal concentration-via microdilution broth test and in vitro valuation of antibacterial efficacies-of the anti-biofilm properties of the studied herbal extractions. Results: Our study evaluated the phytochemical composition and the antioxidant, antibacterial, and anti-biofilm properties of O. vulgare and S. triloba extracts. The analyzed samples contained bioactive compounds, such as phenolics and flavonoids, contributing to the observed strong antioxidant effect. Furthermore, they exhibited notable activity against oral biofilm formation and demonstrated significant antibacterial efficacy against dental caries' microorganisms as well as food pathogens. Despite methodological variations, all extracts showed significant antioxidant capacity and promising antibacterial activity against various pathogens, including resistant strains, while also inhibiting biofilm formation. Although limited to two plant species and facing methodological constraints, this study lays the groundwork for future research, indicating the therapeutic potential of O. vulgare and S. triloba extracts. Further exploration is needed to report on underlying mechanisms and validate efficacy through clinical trials.

Dietary patterns in mild cognitive impairment and dementia in older adults from Yucatan, Mexico

Background

Some dietary patterns and dietary components have an important role in preventing and helping to improve patients' quality of life of individuals with Mild Cognitive Impairment (MCI) and dementia. In Mexico, it is unknown what the dietary patterns are among older adults with MCI and dementia. We aimed to identify the dietary patterns of older adults with MCI and dementia living in Yucatan, Mexico.

Methods

A cross-sectional study was carried out among 39 patients as controls and 34 individuals as cases (MCI and dementia). A food frequency questionnaire collected diet information, anthropometric and clinical parameters, and lifestyle characteristics. The dietary patterns were evaluated through Partial Least-Squares Discriminant Analysis (PLS-DA).

Results

The food groups that showed discrimination between groups and were classified into the dietary patterns of MCI and dementia individuals were "pastries and cookies," "soups," and "legumes." The dietary pattern of older adults without cognitive impairment was characterized by "nuts and seeds," "candies," "vegetables," "coffee and tea," and "water." The consumption of "pastries and cookies" showed an increasing correlation with serum insulin levels (r = 0.36, p = 0.01), and "soups" showed an inverse correlation with total cholesterol levels (r = -0.36, p = 0.02) in patients with MCI and dementia. In controls, there is a positive correlation between the consumption of "nuts and seeds" (r = 0.333, p = 0.01) and "vegetables" (r = 0.32, p = 0.02) with levels of urea; "coffee and tea" showed a positive association with levels of insulin (r = 0.378, p = 0.05).

Conclusion

The dietary pattern of individuals with MCI and dementia has some nutritional deficiencies. Including an adequate intake of vegetables, fruits, and protein could improve the quality of life of subjects living with these conditions in Yucatan, Mexico.

A Review of the Current Status of Disease-Modifying Therapies and Prevention of Alzheimer's Disease

Alzheimer's disease is the most common form of dementia and includes cognitive, personality, and behavioral changes. The 2024 report from the Alzheimer's Association estimated that 6.9 million adults >65 years in the US are currently living with Alzheimer's disease. Modeling studies predict that this number will double by 2050, and associated healthcare costs will reach $1 trillion. In June 2021, regulatory approval of aducanumab, a humanized recombinant monoclonal antibody to amyloid ß, initially raised expectations for improved disease-modifying therapy. However, in February 2024, production of aducanumab and a post-marketing clinical trial ceased in the US due to the costs and limitations of aducanumab therapy. In March 2024, biobank data identified significant modifiable risk factors for Alzheimer's disease, including diabetes mellitus, exposure to nitrogen dioxide (a proxy for air pollution), and the frequency of alcohol intake. Therefore, modification of identifiable risk factors, combined with testing for disease-susceptibility genes, could be the most effective approach to reduce the incidence. This article aims to review the current status of disease-modifying therapies and prevention of Alzheimer's disease.

Joint effect of abnormal systemic immune-inflammation index (SII) levels and diabetes on cognitive function and survival rate: A population-based study from the NHANES 2011-2014

OBJECTIVE

The purpose of this study was to investigate whether the combination of abnormal systemic immune-inflammation index (SII) levels and hyperglycemia increased the risk of cognitive function decline and reduced survival rate in the United States.

METHODS

This cross-sectional study used data from the National Health and Nutrition Examination Survey (NHANES) database from 2011-2014 and enrolled 1,447 participants aged 60 years or older. Restricted cubic splines (RCS), linear regression and kaplan-meier(KM) curve were employed to explore the combined effects of abnormal SII and hyperglycemia on cognitive function and survival rate, and subgroup analysis was also conducted.

RESULTS

The RCS analysis revealed an inverted U-shaped relationship between lgSII levels and cognitive function. Linear regression analysis indicated that neither abnormal SII nor diabetes alone significantly contributed to the decline in cognitive function compared to participants with normal SII levels and blood glucose. However, when abnormal SII coexisted with diabetes (but not prediabetes), it resulted to a significant decline in cognitive function. After adjusting for various confounding factors, these results remained significant in Delayed Word Recall (β:-0.76, P<0.05) and Digit Symbol Substitution tests (β:-5.02, P<0.05). Nevertheless, these results showed marginal significance in Total Word Recall test as well as Animal Fluency test. Among all subgroup analyses performed, participants with both abnormal SII levels and diabetes exhibited the greatest decline in cognitive function compared to those with only diabetes. Furthermore, KM curve demonstrated that the combination of abnormal SII levels and diabetes decreased survival rate among participants.

CONCLUSION

The findings suggest that the impact of diabetes on cognitive function/survival rate is correlated with SII levels, indicating that their combination enhances predictive power.

A bibliometric analysis on the health behaviors related to mild cognitive impairment

Background

Mild cognitive impairment (MCI) is commonly defined as a transitional subclinical state between normal aging and dementia. A growing body of research indicates that health behaviors may play a protective role against cognitive decline and could potentially slow down the progression from MCI to dementia. The aim of this study is to conduct a bibliometric analysis of literature focusing on health behaviors and MCI to summarize the factors and evidence regarding the influence of health behaviors on MCI.

Methods

The study performed a bibliometric analysis by retrieving publications from the Science Citation Index and Social Sciences Citation Index sub-databases within the Web of Science Core Collection. Utilizing VOSviewer and CiteSpace software, a total of 2,843 eligible articles underwent co-citation, co-keywords, and clustering analyses. This methodology aimed to investigate the current status, trends, major research questions, and potential future directions within the research domain.

Results

The bibliometric analysis indicates that research on healthy behaviors in individuals with MCI originated in 2002 and experienced rapid growth in 2014, reflecting the increasing global interest in this area. The United States emerged as the primary contributor, accounting for more than one-third of the total scientific output with 982 articles. Journals that published the most articles on MCI-related health behaviors included "Journal of Alzheimer's Disease," "Neurobiology of Aging," "Frontiers in Aging Neuroscience," and other geriatrics-related journals. High-impact papers identified by VOSviewer predominantly cover concepts related to MCI, such as diagnostic criteria, assessment, and multifactorial interventions. Co-occurrence keyword analysis highlights five research hotspots in health behavior associated with MCI: exercise, diet, risk factors and preventive measures for dementia, cognitive decline-related biomarkers, and clinical trials.

Conclusion

This study provides a comprehensive review of literature on health behavior in individuals with MCI, emphasizing influential documents and journals. It outlines research trends and key focal points, offering valuable insights for researchers to comprehend significant contributions and steer future studies.

Association of physical activity and vitamin D deficiency with cognitive impairment in older adults: a population based cross-sectional analysis

Objectives

The global aging situation is becoming increasingly critical and cognitive impairment in the elderly has become a public health burden of concern. Physical activity (PA) and vitamin D may play a key role in improving cognitive impairment. However, little studies have examined the interaction between these two. The purpose of this study was to assess the association of PA and vitamin D with cognitive impairment in older adults, as well as the interactions of PA and vitamin D.

Materials and methods

This study was conducted by multi-stage random sampling of elderly people ≥60 years old, and a total sample of 2,492 (1,207 male and 1,285 female, mean age of 69.41 ± 6.75 years) with complete data was included in the analysis. PA was assessed by the Global Physical Activity Questionnaire, and < 600 MET-min/week was used as the division criteria. Serum vitamin D was measured by high-performance liquid chromatography tandem mass spectrometry, and 25-hydroxyvitamin D2/D3 concentration < 20 ng/mL was used as a vitamin D deficiency criterion. Cognitive function was assessed by three subtests: the Consortium to Establish a Registry for Alzheimer's disease word learning test (CERAD-WL) for immediate and delayed learning, the Animal Fluency Test (AFT) for verbal fluency; and the Digit Symbol Substitution Test (DSST) for information processing speed and switching attention. All three subtests were scored at less than the lowest quartile of the score as a criterion for cognitive impairment. Statistical analysis was performed using SPSS for chi-square test, rank sum test, interaction analysis, subgroup analysis, and regression analysis.

Results

Lower level of PA is associated with higher odds of cognitive impairment (CERAD W-L: OR = 1.596, 95% CI: 1.338-1.905, p < 0.001; AFT: OR = 1.833, 95% CI: 1.534-2.190, p < 0.001; DSST: OR = 1.936, 95% CI: 1.609-2.329, p < 0.001). Vitamin D deficiency has significant effects in AFT (OR = 1.322, 95% CI: 1.103-1.584, p = 0.003) and DSST (OR = 1.619, 95% CI: 1.345-1.948, p < 0.001). After adjusted for covariates, PA and vitamin D have multiplicative interaction on AFT (OR = 0.662, 95% CI: 0.448-0.977, p = 0.038) and DSST (OR = 0.775, 95% CI: 0.363-0.868, p = 0.009). The interaction between PA and vitamin D was not significant in the CERAD W-L (OR = 0.757, 95% CI: 0.508-1.128, p = 0.172).

Conclusion

The results showed that lower level of PA and vitamin D deficiency were associated with higher odds of cognitive impairment in the elderly population and that there was a multiplicative interaction between PA and vitamin D on cognitive function, with a significant effect of vitamin D on cognitive impairment in high PA conditions.

Effectiveness of a combined lifestyle intervention for older people in long-term care: A randomized controlled trial

PURPOSE

Lifestyle medicine interventions combining physical, nutritional, and psychological components have been found effective in general older population. However, evidence from the long-term care (LTC) is scarce.

METHODS

We conducted a pragmatic, two-arm, parallel group, superiority randomized controlled trial. Residents living in a LTC facility for one or more years, able to discern and to express informed consent, and requiring nursing care were considered eligible. The three-months intervention combined bi-weekly physical exercise groups, a healthy diet, and weekly psychological wellbeing sessions. Patients of the control group were subjected to routine care. At the end of the study participants were assessed using Barthel Index, Katz Activities of Daily Living, and Tinetti scales.

RESULTS

A total of 54 patients with a mean age of 84 years took part to the study. Physical exercise and psychological wellbeing sessions were mostly attended by all the subjects of the intervention group. Both groups took less calories than planned in the diets; in addition, the intervention group showed a lower energy and carbohydrates intake than the control group. At the end of the study, the intervention group showed a significant improvement in the total scores of all the scales.

CONCLUSIONS

This intervention was effective in improving functionality in older people living in the LTC setting. Results were achieved in a short timeframe, likely due to synergistic interactions between components. However, a further exploration of underlying factors is needed, to better understand the barriers that hampered a complete intervention delivery in this context.

Monitoring risk factors for dementia in middle-aged and older adults: a longitudinal study

Given the importance of dementia syndrome and its impacts on the population, interest in studying modifiable risk factors for dementia is growing.

Objective

To compare the prevalence of risk factors for dementia in middle-aged and older adults over a two-year period and to identify what variables in baseline were predictive of cognitive decline in the follow-up.

Methods

Longitudinal and quantitative study, with follow-up evaluation after two years, conducted with 200 participants aged 45 years or more, registered in Primary Care Units. In the baseline (2018/2019) and follow-up (2021) assessments, sociodemographic data were collected, and cognitive performance and risk factors for dementia were evaluated (education, hearing loss, head trauma, high blood pressure, alcohol use, obesity, smoking, depressive symptoms, social isolation, physical inactivity, and diabetes mellitus). Data were compared using the McNemar's test. Individual multinomial logistic regression models were performed to identify the factors associated with cognitive decline after two years.

Results

The percentages of low education, traumatic brain injury, and smoking remained the same in both assessments. There was a significant increase in the prevalence of high blood pressure (from 55.0 to 62.0%) and physical inactivity (from 58.5 to 74.5%) and a significant reduction in social isolation (from 25.0 to 18.0%). Participants with depressive symptoms in baseline had a higher risk of cognitive decline in follow-up.

Conclusion

There was an increase in the prevalence of high blood pressure and physical inactivity and a reduction in social isolation after two years. Depressive symptoms predict cognitive decline.

Effectiveness of Partially Hydrolyzed Guar Gum on Cognitive Function and Sleep Efficiency in Healthy Elderly Subjects in a Randomized, Double-Blind, Placebo-Controlled, and Parallel-Group Study

The consumption of functional foods in a daily diet is a promising approach for the maintenance of cognitive health. The present study examines the effects of water-soluble prebiotic dietary-fiber, partially hydrolyzed guar gum (PHGG), on cognitive function and mental health in healthy elderly individuals. Participants consumed either 5 g/day of PHGG or a placebo daily for 12 weeks in this randomized, double-blind, placebo-controlled, and parallel-group study. An assessment of cognitive functions, sleep quality, and subjective mood evaluations was performed at baseline and after 8 and 12 weeks of either PHGG or placebo intake. The visual memory scores in cognitive function tests and sleepiness on rising scores related to sleep quality were significantly improved in the PHGG group compared to the placebo group. No significant differences were observed in mood parameters between the groups. Vigor-activity scores were significantly improved, while the scores for Confusion-Bewilderment decreased significantly in the PHGG group when compared to the baseline. In summary, supplementation with PHGG was effective in improving cognitive functions, particularly visual memory, as well as enhancing sleep quality and vitality in healthy elderly individuals (UMIN000049070).

Medium-Chain Triglycerides (MCTs) for the Symptomatic Treatment of Dementia-Related Diseases: A Systematic Review

Pathomechanisms of dementias involve increasing damage to neuronal energy metabolism, resulting in degeneration-related insulin resistance and glucose hypometabolism. In this case, ketone bodies can provide an alternative energy source. Supplementation with medium-chain triglycerides (MCTs), which can induce ketogenesis, may alleviate brain energy deficits and improve neuronal function. This review aims to determine the effectiveness of MCT as a symptomatic treatment approach. The systematic literature search was conducted in April 2023 following the Cochrane Handbook and PRISMA guidelines. A total of 21 studies were included, comprising eight uncontrolled trials and 13 RCTs investigating the effects of MCT on Alzheimer's disease (AD) and mild cognitive impairment (MCI). A substantial increase in plasma ketone levels and brain metabolic rates was observed. Cognitive assessments showed only occasional or domain-specific performance improvements. The effects on functional abilities or psychological outcomes have been inadequately studied. Besides gastrointestinal side effects, no harmful effects were observed. However, the evidence was severely weakened by heterogeneous and poorly designed study protocols, bias, and conflicts of interest. In conclusion, the ketogenic properties of MCTs may have beneficial effects on brain metabolism in AD and MCI but do not always result in measurable clinical improvement. Current evidence is insufficient to recommend MCT as a comparable symptomatic treatment option.

Nutritional Supplements for Healthy Aging: A Critical Analysis Review

Background: Healthy aging is defined as survival to advanced age while retaining autonomy in activities of daily living, high societal participation, and good quality of life. Sarcopenia, insomnia, cognitive impairment, and changes in sensation can be key hinderances to healthy aging, but nutritional supplements may abate their impact. As research advances, an updated review on their efficacy on age-related conditions is warranted. Results: Sarcopenia can be mitigated through proper protein intake, supplements like creatine, and in certain situations Branched-Chain Amino Acids and Vitamin D, in adults over 65. Melatonin supplementation has moderate evidence for improving sleep, while valerian root lacks evidence. Magnesium, tart cherry, and kiwifruits have shown promising impacts on sleep in limited articles. Magnesium, Vitamin D, and B vitamin supplementation have been shown to improve cognition in those with mild cognitive impairment and Alzheimer's disease but require further study prior to recommendation. The Age-Related Eye Disease Study supplement combination is routinely recommended to reduce risk of progression to advance stages of age-related macular degeneration. Alpha-Lipoic Acid and Folate have been investigated for their roles in mitigating age-related hearing losses. Conclusions: Nutritional supplements and lifestyle changes may mitigate disabilities across multiple domains of age-related illnesses and promote healthy aging.

Platelet Dynamics in Neurodegenerative Disorders: Investigating the Role of Platelets in Neurological Pathology

Background: Neurological disorders, particularly those associated with aging, pose significant challenges in early diagnosis and treatment. The identification of specific biomarkers, such as platelets (PLTs), has emerged as a promising strategy for early detection and intervention in neurological health. This systematic review aims to explore the intricate relationship between PLT dynamics and neurological health, focusing on their potential role in cognitive functions and the pathogenesis of cognitive disorders. Methods: Adhering to PRISMA guidelines, a comprehensive search strategy was employed in the PubMed and Scholar databases to identify studies on the role of PLTs in neurological disorders published from 2013 to 2023. The search criteria included studies focusing on PLTs as biomarkers in neurological disorders, their dynamics, and their potential in monitoring disease progression and therapy effectiveness. Results: The systematic review included 104 studies, revealing PLTs as crucial biomarkers in neurocognitive disorders, acting as inflammatory mediators. The findings suggest that PLTs share common features with altered neurons, which could be utilised for monitoring disease progression and evaluating the effectiveness of treatments. PLTs are identified as significant biomarkers for detecting neurological disorders in their early stages and understanding the pathological events leading to neuronal death. Conclusions: The systematic review underscores the critical role of PLTs in neurological disorders, highlighting their potential as biomarkers for the early detection and monitoring of disease progression. However, it also emphasises the need for further research to solidify the use of PLTs in neurological disorders, aiming to enhance early diagnosis and intervention strategies.

The prevalence and risk factors study of cognitive impairment: Analysis of the elderly population of Han nationality in Hunan province, China

OBJECTIVE

A large number of studies have found that the prevalence of cognitive impairment varies in different regions. However, data on cognitive impairment in the Chinese population is still lacking. The goal of this study was to assess the prevalence of cognitive impairment among the elderly in a region of China and explore the associated risk factors.

METHODS

We performed a population-based cross-sectional survey from April to June 2022. Residents come from three villages and six urban communities in the county-level city of Liuyang in southern China (N = 3233) and the coverage rate of our study population reached 73%. Participants were assessed with a series of clinical examinations and neuropsychological measures. A total of 2598 participants were selected after filtering out those under 60 years old or with incomplete data. Patients with cognitive impairment included those with mild cognitive impairment (MCI) or dementia who met standard diagnostic criteria.

RESULTS

The prevalence of cognitive impairment, MCI, and dementia among participants aged 60 years and older were 21.48% (95% CI, 19.90-23.10), 15.70% (95% CI, 14.30-17.10), and 5.77 (95% CI, 4.90-6.70), respectively. And residents in villagers were more likely to have cognitive impairment than in urban communities (p < 0.001). Age growth and education level were independent influencing factors for cognitive impairment in all populations (p < 0.001). For lifestyles factors, both smoking and drinking reduced the risk of cognitive impairment (p < 0.05), but when further quantified, the link disappeared. Moreover, having cerebrovascular disease and severe vision impairment were risk factors (p < 0.05).

CONCLUSION

A representative prevalence of cognitive impairment, MCI, and dementia was found in the elderly Han Chinese population in Southern China. And we further explored the role of known risk factors, particularly in physical activity, smoking, and alcohol consumption.

Vascular dementia: From pathobiology to emerging perspectives

Vascular dementia (VaD) is the second most common type of dementia. VaD is synonymous with ageing, and its symptoms place a significant burden on the health and wellbeing of older people. Despite the identification of a substantial number of risk factors for VaD, the pathological mechanisms underpinning this disease remain to be fully elucidated. Consequently, a biogerontological imperative exists to highlight the modifiable lifestyle factors which can mitigate against the risk of developing VaD. This review will critically examine some of the factors which have been revealed to modulate VaD risk. The survey commences by providing an overview of the putative mechanisms which are associated with the pathobiology of VaD. Next, the factors which influence the risk of developing VaD are examined. Finally, emerging treatment avenues including epigenetics, the gut microbiome, and pro-longevity pharmaceuticals are discussed. By drawing this key evidence together, it is our hope that it can be used to inform future experimental investigations in this field.

Exploring relevant factors of cognitive impairment in the elderly Chinese population using Lasso regression and Bayesian networks

Older adults are highly susceptible to developing cognitive impairment(CI). Various factors contribute to the prevalence of CI, but the potential relationships among these factors remain unclear. This study aims to explore the relevant factors associated with CI in Chinese older adults and analyze the potential relationships between CI and these factors.We analyzed the data on 6886 older adults aged≥60 from the China Health and Retirement Longitudinal Study (CHARLS) 2018. Lasso regression was initially used to screening variables. Bayesian Networks(BNs) were used to identify the correlates of CI and potential associations between factors. After screening with Lasso regression, 11 variables were finally included in the BNs. The BNs, by establishing a complex network relationship, revealed that age, education, and indoor air pollution were the direct correlates affecting the occurrence of CI in older adults. It also indicated that marital status indirectly influenced CI through age, and residence indirectly linked to CI through two pathways: indoor air pollution and education.Our findings underscore the effectiveness of BNs in unveiling the intricate network linkages among CI and its associated factors, holding promising applications. It can serve as a reference for public health departments to address the prevention of CI in the elderly.