National Institutes of Health State-of-the-Science Conference statement: preventing alzheimer disease and cognitive decline

Carotenoid Supplementation for Alleviating the Symptoms of Alzheimer's Disease

Alzheimer's disease (AD) is characterized by, among other things, dementia and a decline in cognitive performance. In AD, dementia has neurodegenerative features and starts with mild cognitive impairment (MCI). Research indicates that apoptosis and neuronal loss occur in AD, in which oxidative stress plays an important role. Therefore, reducing oxidative stress with antioxidants is a natural strategy to prevent and slow down the progression of AD. Carotenoids are natural pigments commonly found in fruits and vegetables. They include lipophilic carotenes, such as lycopene, α- and β-carotenes, and more polar xanthophylls, for example, lutein, zeaxanthin, canthaxanthin, and β-cryptoxanthin. Carotenoids can cross the blood-brain barrier (BBB) and scavenge free radicals, especially singlet oxygen, which helps prevent the peroxidation of lipids abundant in the brain. As a result, carotenoids have neuroprotective potential. Numerous in vivo and in vitro studies, as well as randomized controlled trials, have mostly confirmed that carotenoids can help prevent neurodegeneration and alleviate cognitive impairment in AD. While carotenoids have not been officially approved as an AD therapy, they are indicated in the diet recommended for AD, including the consumption of products rich in carotenoids. This review summarizes the latest research findings supporting the potential use of carotenoids in preventing and alleviating AD symptoms. A literature review suggests that a diet rich in carotenoids should be promoted to avoid cognitive decline in AD. One of the goals of the food industry should be to encourage the enrichment of food products with functional substances, such as carotenoids, which may reduce the risk of neurodegenerative diseases.

Association between the geriatric nutritional risk index and cognitive functions in older adults: a cross-sectional study from National Health and Nutrition Examination Survey

Objective

To investigate the associations between the geriatric nutritional risk index (GNRI) with cognitive functions among U.S. older adults. (Patients were classified into two nutrition risk groups based on the GNRI).

Methods

Our analysis utilized data from the cross-sectional National Health and Nutrition Examination Survey (NHANES) conducted between 2011 and 2014. Cognitive function was measured using CERAD test, AFT and DSST. Composite z-scores were obtained by summing test-specific z-scores of the above three cognitive tests and were used to assess the global cognitive function. We employed weighted logistic regression models to evaluate the associations between GNRI and nutritional status (low and high GNRI) with cognitive function among older participants. The non-linear relationship was described using fitted smoothed curves and threshold effect analyses. Subgroup analysis and interaction tests were also conducted.

Results

This study included 2,592 older participants aged 60 years and older. After adjusting for confounding variables, the GNRI was positively associated with AFT (β = 0.05, 95% CI 0.005-0.096, p-value = 0.0285), DSST (β = 0.192, 95% CI 0.078-0.305, p-value = 0.0010) and the composite z-scores (β = 0.027, 95% CI 0.010-0.044, p-value = 0.0024). The results also showed that the high-GNRI group was significantly associated with AFT (β = 0.922, 95% CI 0.166-1.677, p-value = 0.0169), DSST (β = 2.791, 95% CI 0.884-4.698, p-value = 0.0042) and composite z-scores (β = 0.405, 95% CI 0.115-0.695, p-value = 0.0062) likewise had significant positive correlations, using the low-GNRI group as a reference. In addition, inflection points with CERAD and composite z-scores were found at GNRI of 108.016, and 105.371, respectively. Specifically, on the left side of the inflection point GNRI levels were positively correlated with CERAD and composite z-scores (CERAD β = 0.087, 95% CI 0.024-0.150, p-value = 0.0070; composite z-scores β = 0.065, 95% CI 0.040-0.091, p-value <0.0001), while on the right side of the inflection point were significantly negatively associated (CERAD β = -0.295, 95% CI -0.529 to -0.062, p-value = 0.0133, composite z-scores β = -0.050, 95% CI -0.091 to -0.008, p-value = 0.0184).

Conclusion

Lower GNRI was associated with poorer performance in several cognitive domains. Additionally, there was a non-linear positive association between GNRI and cognitive function in normal nutritional states, for excessive GNRI may cause cognitive decline.

The Relationship between Healthy Vascular Aging with the Mediterranean Diet and Other Lifestyles in the Spanish Population: The EVA Study

The aim of this study was to analyze the relationship between healthy vascular aging (HVA) and the Mediterranean diet alongside other lifestyles in a Spanish population aged 35 to 75 years without previous cardiovascular diseases.

METHODS

In this cross-sectional descriptive study, 501 individuals aged 35 to 75 years were recruited from five health centers by random sampling stratified by age and sex (55.90 ± 14.24 years, 49.70% men). HVA was determined in two steps. Step 1: Subjects with vascular damage to the carotid arteries or peripheral arterial disease were classified as non-HVA. Step 2: The study population was classified by age and sex using the percentiles of the vascular aging index (VAI), with VAI ≤p25 considered HVA and >p25 considered non-HVA. The VAI was estimated using the following formula (VAI = (log (1.09) × 10 cIMT + log (1.14) cfPWV) × 39.1 + 4.76. Carotid-femoral pulse wave velocity (cfPWV) was measured with the SphygmoCor® device, and carotid intima-media thickness using Sonosite Micromax® ultrasound. Mediterranean diet (MD) adherence, alcohol and tobacco use were recorded through validated questionnaires. Physical activity was assessed with the ActiGraph-GT3X® accelerometer.

RESULTS

The mean VAI value was 61.23 ± 12.86 (men-63.47 ± 13.75 and women-59.04 ± 11.54; p < 0.001). HVA was found in 18.9% (men-19.9% and women-17.8%). In the multiple regression analysis after adjusting for possible confounding factors, the mean VAI value showed a positive association with alcohol use (β = 0.020) and sedentary hours per week (β = 0.109) and a negative association with hours of activity per week (β = -0.102) and with the number of healthy lifestyles (β = -0.640). In the logistic regression analysis, after adjusting for possible confounding factors and compared to those classified as non-HVA, subjects classified as HVA were more likely to show MD adherence (OR = 0.571), do more than 26 h per week of physical activity (OR = 1.735), spend under 142 h per week being sedentary (OR = 1.696), and have more than two healthy lifestyles (OR = 1.877).

CONCLUSION

The results of this study suggest that the more time spent doing physical activity and the less time spent in a sedentary state, the lower the vascular aging index and the greater the likelihood of being classified in the group of subjects with HVA.

The Interplay of Protein Aggregation, Genetics, and Oxidative Stress in Alzheimer's Disease: Role for Natural Antioxidants and Immunotherapeutics

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that comprises amyloid-beta protein (Aβ) as a main component of neuritic plaques. Its deposition is considered a trigger for AD pathogenesis, progression, and the clinical symptoms of cognitive impairment. Some distinct pathological features of AD include phosphorylation of tau protein, oxidative stress, and mitochondrial dysfunction. These pathological consequences tend to produce reactive oxygen species (ROS), resulting in the dysregulation of various signaling pathways of neuroinflammation and neurodegeneration. The relationship between the Aβ cascade and oxidative stress in AD pathogenesis is like a "chicken and egg" story, with the etiology of the disease regarding these two factors remaining a question of "which comes first." However, in this review, we have tried our best to clarify the interconnection between these two mechanisms and to show the precise cause-and-effect relationship. Based on the above hallmarks of AD, several therapeutic strategies using natural antioxidants, monoclonal antibodies, and vaccines are employed as anti-Aβ therapy to decrease ROS, Aβ burden, chronic neuroinflammation, and synaptic failure. These natural antioxidants and immunotherapeutics have demonstrated significant neuroprotective effects and symptomatic relief in various in vitro and in vivo models, as well as in clinical trials for AD. However, none of them have received final approval to enter the drug market for mitigating AD. In this review, we extensively elaborate on the pitfalls, assurances, and important crosstalk between oxidative stress and Aβ concerning current anti-Aβ therapy. Additionally, we discuss future strategies for the development of more Aβ-targeted approaches and the optimization of AD treatment and mitigation.

Association between Subjective Cognitive Complaints and Sleep Disturbance among Community-Dwelling Elderly Individuals in Japan

Subjective cognitive complaints (SCCs) are a crucial modifiable risk factor for dementia. There is increasing interest in the association between SCC and sleep disturbance; however, the effects of sleep disturbance on SCC development among community-dwelling elderly individuals in Japan remain unclear. We aimed to cross-sectionally investigate the association between SCC and sleep disturbance, with adjustment for multiple factors related to cognitive decline, among 241 community-dwelling elderly persons without cognitive impairment. The measures were SCCs (Kihon Checklist-Cognitive Function, KCL-CF), sleep disturbance (Japanese version of the Athens Insomnia Scale, AIS-J), general cognitive function (Mini-Mental State Examination), and depressive symptoms (five-item version of the Geriatric Depression Scale [GDS-5]). The following data were collected: sex, age, educational history, whether the participants had visited a medical institution for diseases (hypertension, diabetes, hyperlipidemia, heart disease), and the presence/absence of established risk factors (hearing loss, history of head injury, drinking habits, smoking habits, social isolation, and physical inactivity and activity). Based on the KCL-CF, 96 and 145 participants were considered to have and lack SCCs, respectively. On logistic regression analysis, the AIS-J score and smoking history were significantly associated with SCCs. Our findings suggest that sleep disturbance is associated with SCC development among community-dwelling elderly people in Japan. Evaluating and managing sleep disturbances can be important in preventing SCCs and dementia.

Current Health Status of Gulf War Deployed and Gulf War Era Veterans Who Use Veterans Affairs Health Care

Background: Although some recent studies have examined the health of female Gulf War (GW) deployed and non-deployed GW era veterans, these all relied on self-report, which can be inaccurate and subject to recall bias. This study investigated the current health of GW deployed and non-deployed GW era female and male veterans using Veterans Health Administration (VHA) electronic health records (EHR). Methods: We performed a cohort study of deployed GW and non-deployed GW era veterans, identified from a list from the Defense Manpower Data Center (DMDC). We used the VA-Frailty Index (VA-FI), calculated with VHA administrative claims and EHR, as a proxy measure of current health. Results: We identified 402,869 veterans (351,496 GW deployed; 51,3373 non-deployed GW era; 38,555 female) in VHA databases. Deployed female veterans had the highest VA-FI (i.e., were frailest) despite being younger than deployed and non-deployed male veterans and non-deployed female veterans. Compared with deployed male veterans, deployed females were more likely to be pre-frail, mildly, and moderately frail. Health differences between deployed and non-deployed female veterans were more prominent among older (60+ years) than younger (<60 years) veterans. Conclusions: Mirroring reports from recent, smaller survey studies of users and non-users of VA health care, findings from this cohort study indicate that deployed female GW veterans who use VA health care are frailer and have more health deficits than non-deployed female GW era and deployed male GW veterans. Because deployed female GW veterans appear to have additional health care needs, this may warrant increased outreach from women's clinics at VA hospitals.

Walking time and genetic predisposition for Alzheimer's disease: Results from the HELIAD study

Objective: Our study aimed to explore whether physical condition might affect the association between genetic predisposition for Alzheimer's Disease (AD) and AD incidence. Methods: The sample of participants consisted of 561 community-dwelling adults over 64 years old, without baseline dementia (508 cognitively normal and 53 with mild cognitive impairment), deriving from the HELIAD, an ongoing longitudinal study with follow-up evaluations every 3 years. Physical condition was assessed at baseline through walking time (WT), while a Polygenic Risk Score for late onset AD (PRS-AD) was used to estimate genetic predisposition. The association between WT and PRS-AD with AD incidence was evaluated with Cox proportional hazard models adjusted for age, sex, education years, global cognition score and APOE ε-4 genotype. Then, the association between WT and AD incidence was investigated after stratifying participants by low and high PRS-AD. Finally, we examined the association between PRS-AD and AD incidence after stratifying participants by WT. Results: Both WT and PRS-AD were connected with increased AD incidence (p < 0.05), after adjustments. In stratified analyses, in the slow WT group participants with a greater genetic risk had a 2.5-fold higher risk of developing AD compared to participants with lower genetic risk (p = 0.047). No association was observed in the fast WT group or when participants were stratified based on PRS-AD. Conclusions: Genetic predisposition for AD is more closely related to AD incidence in the group of older adults with slow WT. Hence, physical condition might be a modifier in the relationship of genetic predisposition with AD incidence.

An Assessment of Physical Activity and Risk Factors in People Living with Dementia: Findings from a Cross-Sectional Study in a Long-Term Care Facility in Vietnam

BACKGROUND

People living with dementia (PLWD) may experience substantial cognitive decline as the disease progresses, which interferes with their daily activities. This study aimed to assess physical activity (PA) performance and care dependency (CD) and identify factors related to PA among PLWD.

METHODS

We conducted a cross-sectional study in 63 PLWD from National Geriatrics Hospital, Vietnam, from 2021 to 2023. We used the Mini Nutritional Assessment (MNA), International Physical Activity Questionnaire (IPAQ), and Care Dependency Scale (CDS) to assess the nutritional status and the levels of PA and CD, respectively. We used the Mann-Whitney test to compare the differences in the PA types and CD levels between dementia levels and a multivariable logistics regression model to analyze factors related to PA.

RESULTS

More than half of the subjects had mild dementia. In total, 35% of the PLWD had a low level of PA, and 46.3% were completely independent of care. The mean score in each CDS aspect of the subjects with moderate/severe dementia was statistically significantly lower than that of those with mild dementia (p ≤ 0.05). Lower dependency (OR = 0.9; 95% CI = 0.88-0.99) and malnutrition (OR = 15.4; 95% CI = 1.18-20.21) were associated with insufficient PA in the PLWD.

CONCLUSION

Formal caregivers and healthcare workers should encourage PLWD to perform physical activities at any level and personalize the development of tailored and nutritional care strategies for each individual.

Sex and race differences in the association of albumin with cognitive function in older adults

BACKGROUND

With the increasing aging population, dementia has become a significant socioeconomic burden. However, the effects of albumin on delayed recall (DR) impairment remain unclear, and there are limited reports on sex and race differences in this relationship. This study aimed to investigate the association between albumin levels and DR impairment in older adults.

METHODS

A total of 1507 normal cognitive function and 553 DR impairment from the National Health and Nutrition Examination Survey (NHANES) 2011-2014 were included in this cross-sectional analysis. Participants aged 60 years and above were assessed using the Consortium to Establish a Registry for Alzheimer's Disease DR (CERAD-DR) test to evaluate cognitive function. Participants were categorized into DR impairment and normal cognitive function groups according to their CERAD-DR scores. Logistic regression analyses, generalized additive models, and fitted smoothing curves were utilized for data analysis.

RESULTS

After adjusting for potential confounders, a negative association was found between albumin levels and cognitive function (odds ratio [OR] = 0.60, 95% confidence interval [CI] 0.41-0.87). Subgroup analysis stratified by sex, race/ethnicity, and age revealed that the negative association remained significant in men (OR = 0.53, 95%CI 032-0.87), Blacks (OR = 0.35, 95%CI 0.17-0.74), and the age group of 60-70 years (OR = 0.48, 95%CI 0.28-0.81). However, no significant association was observed in women (OR = 0.72, 95%CI 0.41-1.28), whites (OR = 0.58, 95%CI 0.31-1.07), or Mexican Americans (OR = 1.11, 95%CI 0.35-3.46), as well as the age group of 71-80 years (OR = 0.62, 95%CI 0.37-1.03).

CONCLUSIONS

Our study suggests that elevated albumin levels are associated with a decreased incidence of cognitive function impairment, particularly in older men and Blacks. This finding indicates that maintaining high levels of albumin may be beneficial for cognitive function in older adults.

Mild Cognitive Impairment Progression and Alzheimer's Disease Risk: A Comprehensive Analysis of 3553 Cases over 203 Months

This study aimed to elucidate the long-term progression of mild cognitive impairment (MCI) within a comprehensive longitudinal dataset, distinguish it from healthy aging, explore the influence of a dementia subtype on this progression, and identify potential contributing factors. Patients with prodromal and preclinical cases underwent regular neuropsychological assessments utilizing various tools. The study included a total of 140 participants with MCI, categorized into Alzheimer's disease (AD) and non-AD subtypes. Our dataset revealed an overall progression rate of 92.8% from MCI to the clinical stage of dementia during the follow-up period, with an annual rate of 15.7%. Notably, all prodromal cases of Lewy body dementia/Parkinson's disease (LBD/PDD) and frontotemporal dementia (FTD) advanced to clinical stages, whereas 7% of vascular dementia (VaD) cases and 8.4% of AD cases remained in the prodromal stage throughout follow-up. Furthermore, we observed a faster progression rate in MCI-AD cases compared to non-AD sufferers (53.9% vs. 35.5%, Entropy: 0.850). This study revealed significant cognitive changes in individuals with MCI over time. The mini-mental state examination (MMSE), global deterioration scale (GDS), and calculation tests were the most effective tests for evaluation of MCI. These findings may offer valuable insights for the development of personalized interventions and management strategies for individuals with MCI.

Association Between Composite Dietary Antioxidant Index and Cognitive Function Among Aging Americans from NHANES 2011-2014

Background

Antioxidant diets are considered to be protective factors for cognitive function. However, comprehensive measures of antioxidant diets are lacking.

Objective

To examine the association between the Composite Dietary Antioxidant Index (CDAI) and cognitive function in the elderly.

Methods

This cross-sectional study included a total of 2,456 participants (≥60 years old) from NHANES 2011-2014. Calculation of CDAI based on 6 minerals and vitamins (manganese, selenium, zinc, vitamins A, C, and E). Cognitive function was measured by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word Learning sub-test, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). We also created a composite cognitive z-score to represent global cognition. The statistical analyses we used included multiple linear regression analyses, subgroup analyses, curve-fitting analyses, and threshold effects analyses.

Results

After controlling for demographic characteristics, lifestyle factors, and disease history, multivariate linear regression analyses showed that increased CDAI was positively associated with scores on global cognitive function and each cognitive domain (p < 0.05), with subgroup analyses suggesting that this association was more pronounced in stroke patients (p for interaction < 0.05). Curve-fitting analyses and threshold effect analyses showed saturation effects between CDAI and CREAD Test, AFT, and composite Z-score, and an inverted U-shaped relationship with DSST, with inflection points of -1.89, 0.79, 1.13, and 1.77, respectively.

Conclusions

Our findings support that higher levels of CDAI are correlated with significantly elevated cognitive function. Maintaining CDAI in an appropriate range may contribute to cognitive health in elderly.

The Longitudinal Association of Egg Consumption with Cognitive Function in Older Men and Women: The Rancho Bernardo Study

This study examines the prospective association of egg consumption with multiple domains of cognitive function in older, community-dwelling men and women followed for 16.3 years. Participants were 617 men and 898 women from the Rancho Bernardo Cohort aged 60 and older, who were surveyed about egg intake/week in 1972-1974, and attended a 1988-1991 research visit, where cognitive function was assessed with 12 tests. Analyses showed that egg intake ranged from 0-24/week (means: men = 4.2 ± 3.2; women = 3.5 ± 2.7; p < 0.0001). In men, covariate-adjusted regressions showed that egg intake was associated with better performance on Buschke total (p = 0.04), long-term (p = 0.02), and short-term (p = 0.05) recall. No significant associations were observed in women (p's > 0.05). Analyses showed that in those aged <60y in 1972-1974, egg intake was positively associated with scores on Heaton copying (p < 0.04) and the Mini-Mental Status Exam (MMSE; p < 0.02) in men and category fluency (p < 0.05) in women. Egg intake was not significantly associated with odds of poor performance on MMSE, Trails B, or category fluency in either sex. These reassuring findings suggest that there are no long-term detrimental effects of egg consumption on multiple cognitive function domains, and for men, there may be beneficial effects for verbal episodic memory. Egg consumption in middle age may also be related to better cognitive performance later in life.

Subjective and Performance-Based Cognition and Their Associations with Head Injury History in Older Former National Football League Players

PURPOSE

Investigate the association between self-reported subjective and performance-based cognition among older (50-70 years) former professional American football players, as well as the relationship of cognitive measures with concussion history and years of football participation, as a proxy for repetitive head impact exposure.

METHODS

Among older former National Football League (NFL) players ( N = 172; mean age = 60.69 ± 5.64), associations of subjective (Patient Reported Outcome Measurement Information System Cognitive Function-Short Form) and performance-based cognitive measures (Brief Test of Adult Cognition by Telephone [BTACT] Executive Function and Episodic Memory indices) were assessed via univariable and multivariable regression models, with a priori covariates of depression and race. A similar univariate and multivariable regression approach assessed associations between concussion history and years of football participation with subjective and performance-based cognitive measures. In a sample subset ( n = 114), stability of subjective cognitive rating was assessed via partial correlation.

RESULTS

Subjective ratings of cognition were significantly associated with performance-based assessment, with moderate effect sizes (episodic memory ηp2 = 0.12; executive function ηp2 = 0.178). These associations were weakened, but remained significant ( P s < 0.05), with the inclusion of covariates. Greater concussion history was associated with lower subjective cognitive function ( ηp2 = 0.114, P < 0.001), but not performance-based cognition. The strength of association between concussion history and subjective cognition was substantially weakened with inclusion of covariates ( ηp2 = 0.057). Years of participation were not associated with measures of subjective or objective cognition ( P s > 0.05).

CONCLUSIONS

These findings reinforce the importance of comprehensive evaluation reflecting both subjective and objective measures of cognition, as well as the consideration of patient-specific factors, as part of a comprehensive neurobehavioral and health assessment of older former contact sport athletes.

Taste receptor type 1 member 3 mediates diet-induced cognitive impairment in mice

AIMS

Long-term consumption of a western diet (WD), which is characterized by high intake of saturated fats and sugary drinks, causes cognitive impairment. However, the molecular mechanism by which WD induces cognitive impairment remains unclear. Taste receptor type 1 member 3 (TAS1R3), activated by ligands of WD, is expressed in extra-oral tissues, including the brain, and particularly in the hippocampus. This study investigated whether TAS1R3 regulates WD-induced cognitive impairment in mice.

MAIN METHODS

Male C57BL/6J wild-type (WT) and Tas1r3 knock-out (KO) mice were fed either a normal diet (ND) or WD for 18 weeks. Cognitive functions were assessed using novel object recognition and Barnes maze tests. The mechanisms underlying WD-induced cognitive impairment were assessed using RNA-sequencing and bioinformatics analysis.

KEY FINDINGS

Cognitive impairment was observed in WT mice fed WD (WT-WD) compared with WT-ND mice. Conversely, mice lacking TAS1R3 were not cognitively impaired even under long-term WD feeding. Hippocampal transcriptome analysis revealed upregulated AMP-activated protein kinase (AMPK) signaling and increased AMPK-targeted sirtuin 3 expression in KO-WD mice. Pathway enrichment analysis showed that response to oxidative stress was downregulated, whereas neurogenesis was upregulated in dentate gyrus of KO-WD mice. In vitro studies validated the findings, indicating that Tas1r3 knockdown directly upregulated decreased sirtuin 3 expression, its downstream genes-related to oxidative stress, and apoptosis induced by WD condition in hippocampal neuron cells.

SIGNIFICANCE

TAS1R3 acts as a critical mediator of WD-induced cognitive impairment in mice, thereby offering potential as a novel therapeutic target to prevent WD-induced cognitive impairment.

Gut microbiota-derived short chain fatty acids act as mediators of the gut-brain axis targeting age-related neurodegenerative disorders: a narrative review

Neurodegenerative diseases associated with aging are often accompanied by cognitive decline and gut microbiota disorder. But the impact of gut microbiota on these cognitive disturbances remains incompletely understood. Short chain fatty acids (SCFAs) are major metabolites produced by gut microbiota during the digestion of dietary fiber, serving as an energy source for gut epithelial cells and/or circulating to other organs, such as the liver and brain, through the bloodstream. SCFAs have been shown to cross the blood-brain barrier and played crucial roles in brain metabolism, with potential implications in mediating Alzheimer's disease (AD) and Parkinson's disease (PD). However, the underlying mechanisms that SCFAs might influence psychological functioning, including affective and cognitive processes and their neural basis, have not been fully elucidated. Furthermore, the dietary sources which determine these SCFAs production was not thoroughly evaluated yet. This comprehensive review explores the production of SCFAs by gut microbiota, their transportation through the gut-brain axis, and the potential mechanisms by which they influence age-related neurodegenerative disorders. Also, the review discusses the importance of dietary fiber sources and the challenges associated with harnessing dietary-derived SCFAs as promoters of neurological health in elderly individuals. Overall, this study suggests that gut microbiota-derived SCFAs and/or dietary fibers hold promise as potential targets and strategies for addressing age-related neurodegenerative disorders.

Urgent needs of caregiving in ageing populations with Alzheimer's disease and other chronic conditions: Support our loved ones

The ageing process begins at birth. It is a life-long process, and its exact origins are still unknown. Several hypotheses attempt to describe the normal ageing process, including hormonal imbalance, formation of reactive oxygen species, DNA methylation & DNA damage accumulation, loss of proteostasis, epigenetic alterations, mitochondrial dysfunction, senescence, inflammation, and stem cell depletion. With increased lifespan in elderly individuals, the prevalence of age-related diseases including, cancer, diabetes, obesity, hypertension, Alzheimer's, Alzheimer's disease and related dementias, Parkinson's, and other mental illnesses are increased. These increased age-related illnesses, put tremendous pressure & burden on caregivers, family members, and friends who are living with patients with age-related diseases. As medical needs evolve, the caregiver is expected to experience an increase in duties and challenges, which may result in stress on themselves, and impact their own family life. In the current article, we assess the biological mechanisms of ageing and its effect on body systems, exploring lifestyle and ageing, with a specific focus on age-related disorders. We also discussed the history of caregiving and specific challenges faced by caregivers in the presence of multiple comorbidities. We also assessed innovative approaches to funding caregiving, and efforts to improve the medical system to better organize chronic care efforts, while improving the skill and efficiency of both informal and formal caregivers. We also discussed the role of caregiving in end-of-life care. Our critical analysis strongly suggests that there is an urgent need for caregiving in aged populations and support from local, state, and federal agencies.

Developing and validating a nomogram for cognitive impairment in the older people based on the NHANES

Objective

To use the United States National Health and Nutrition Examination Study (NHANES) to develop and validate a risk-prediction nomogram for cognitive impairment in people aged over 60 years.

Methods

A total of 2,802 participants (aged ≥ 60 years) from NHANES were analyzed. The least absolute shrinkage and selection operator (LASSO) regression model and multivariable logistic regression analysis were used for variable selection and model development. ROC-AUC, calibration curve, and decision curve analysis (DCA) were used to evaluate the nomogram's performance.

Results

The nomogram included five predictors, namely sex, moderate activity, taste problem, age, and education. It demonstrated satisfying discrimination with a AUC of 0.744 (95% confidence interval, 0.696-0.791). The nomogram was well-calibrated according to the calibration curve. The DCA demonstrated that the nomogram was clinically useful.

Conclusion

The risk-prediction nomogram for cognitive impairment in people aged over 60 years was effective. All predictors included in this nomogram can be easily accessed from its' user.

World-wide variations in tests of cognition and activities of daily living in participants of six international randomized controlled trials

Background

Better understanding of worldwide variation in simple tests of cognition and global function in older adults would aid the delivery and interpretation of multi-national studies of the prevention of dementia and functional decline.

Method

In six RCTs that measured cognition with the mini-mental state examination (MMSE), Montreal cognitive assessment (MoCA), and activities of daily living (ADL) with the Standardised Assessment of Everyday Global Activities (SAGEA), we estimated average scores by global region with multilevel mixed-effects models. We estimated the proportion of participants with cognitive or functional impairment with previously defined thresholds (MMSE≤24 or MoCA≤25, SAGEA≥7), and with a country-standardised z-score threshold of cognitive or functional score of ≤-1.

Results

In 91,396 participants (mean age 66.6 years [SD 7.8], 31% females) from seven world regions, all global regions differed significantly in estimated cognitive function (z-score differences 0.11-0.45, p<0.001) after accounting for individual-level factors, centre and study. In different regions, the proportion of trial participants with MMSE≤24 or MoCA≤25 ranged from 23-36%; the proportion below a country-standardised z-score threshold of ≤1 ranged from 10-14%. The differences in prevalence of impaired IADL (SAGEA≥7) ranged from 2-6% and by country-standardised thresholds from 3-6%.

Conclusions

Accounting for country-level factors reduced large differences between world regions in estimates of cognitive impairment. Measures of IADL were less variable across world regions, and could be used to better estimate dementia prevalence in large studies.

Association of the Oxidative Balance Score and Cognitive Function and the Mediating Role of Oxidative Stress: Evidence from the National Health and Nutrition Examination Survey (NHANES) 2011-2014

BACKGROUND

Oxidative stress is possibly related to cognitive function decline. The oxidative balance score (OBS) that combines pro- and antioxidant components from diet and lifestyle has been reported to be associated with age-related diseases.

OBJECTIVES

We aimed to investigate the association between OBS and cognitive function in older adults and explore whether oxidative stress mediated this relationship.

METHODS

A total of 1745 adults aged ≥60 y were included in the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Cognitive function was measured using 4 tests: the immediate recall test, delayed recall test, animal fluency test (AFT), and digital symbol substitution test (DSST). Weighted multivariate linear regression and restricted cubic splines (RCS) analyses were used to evaluate the association between OBS and cognitive function, and mediation analysis was used to test the indirect effect of oxidative stress indicators on the association.

RESULTS

The OBS was positively associated with AFT, DSST, and global cognitive function in older adults, and the beta estimates (95% CI) were 0.015 (0.008, 0.034), 0.009 (0.002, 0.025), and 0.030 (0.024, 0.074), moreover, RCS results suggested an approximately linear dose-response relationship between the OBS and these 3 tests. The highest quartiles of these 3 tests were also significantly correlated with OBS. Albumin, uric acid, and serum 25(OH)D concentrations were significant mediators of the relationship between OBS and cognitive function, and the overall mediation effect proportion was 36% when included in 1 model.

CONCLUSIONS

OBS was positively correlated with cognitive function in older adults, and albumin, uric acid, and serum 25(OH)D concentrations could be the driving mediators of the association. The findings emphasize the importance of a healthy, antioxidant diet and lifestyle that contribute to cognitive function. J Nutr 20xx;x:xx.

Amyloid β-based therapy for Alzheimer's disease: challenges, successes and future

Amyloid β protein (Aβ) is the main component of neuritic plaques in Alzheimer's disease (AD), and its accumulation has been considered as the molecular driver of Alzheimer's pathogenesis and progression. Aβ has been the prime target for the development of AD therapy. However, the repeated failures of Aβ-targeted clinical trials have cast considerable doubt on the amyloid cascade hypothesis and whether the development of Alzheimer's drug has followed the correct course. However, the recent successes of Aβ targeted trials have assuaged those doubts. In this review, we discussed the evolution of the amyloid cascade hypothesis over the last 30 years and summarized its application in Alzheimer's diagnosis and modification. In particular, we extensively discussed the pitfalls, promises and important unanswered questions regarding the current anti-Aβ therapy, as well as strategies for further study and development of more feasible Aβ-targeted approaches in the optimization of AD prevention and treatment.

Explainable semi-supervised deep learning shows that dementia is associated with small, avocado-shaped clocks with irregularly placed hands

The clock drawing test is a simple and inexpensive method to screen for cognitive frailties, including dementia. In this study, we used the relevance factor variational autoencoder (RF-VAE), a deep generative neural network, to represent digitized clock drawings from multiple institutions using an optimal number of disentangled latent factors. The model identified unique constructional features of clock drawings in a completely unsupervised manner. These factors were examined by domain experts to be novel and not extensively examined in prior research. The features were informative, as they distinguished dementia from non-dementia patients with an area under receiver operating characteristic (AUC) of 0.86 singly, and 0.96 when combined with participants' demographics. The correlation network of the features depicted the "typical dementia clock" as having a small size, a non-circular or "avocado-like" shape, and incorrectly placed hands. In summary, we report a RF-VAE network whose latent space encoded novel constructional features of clocks that classify dementia from non-dementia patients with high performance.

[Reminiscence program supported by artificial intelligence and based on intangible cultural heritage aimed at the elderly: A pilot study]

INTRODUCTION

Technological applications are an innovative way of providing reminiscence therapy and must meet the users' needs. Intangible cultural heritage as a basis for such therapy has not been explored yet. We evaluated the applicability of a new technological application supported by artificial intelligence for reminiscence therapy based on intangible cultural heritage aimed at older people.

MATERIAL AND METHODS

A prospective observational study was carried out with people aged 65 or over, without cognitive impairment and with mild and moderate cognitive impairment who attended six centers for older people in Spain and Portugal. Participants tested the first prototype of the individualized LONG-REMI program in four consecutive weekly sessions. The usability and satisfaction of the experience were evaluated using the VAS scale at the end of the intervention. Emotions were evaluated using the PANAS scale before and at the end of the intervention.

RESULTS

Data from 56 participants were analysed. For all participants, usability and satisfaction were highly perceived, with scores of 7.75±1.88 and 8.38±1.57, respectively. The positive affect subscale PANAS showed significant changes (28.86±8.88 before the intervention versus 36.70±9.43 post intervention, Z = -4.18, P = 0.000). There were no significant changes in the PANAS negative affect subscale.

CONCLUSIONS

The first prototype of the LONG-REMI technological application can be used by older people both with and without cognitive impairment. This has the potential to be an instrument for future cognitive therapies with stimulating activities and benefits for emotions.

Brain region-specific genome-wide deoxyribonucleic acid methylation analysis in patients with Alzheimer's disease

Objective

Alzheimer's disease (AD) is a neurodegenerative disease characterized by neuropathology and cognitive decline and associated with age. The comprehensive deoxyribonucleic acid methylation (DNAm)-transcriptome profile association analysis conducted in this study aimed to establish whole-genome DNAm profiles and explore DNAm-related genes and their potential functions. More appropriate biomarkers were expected to be identified in terms of AD.

Materials and methods

Illumina 450KGSE59685 dataset AD (n = 54) and HC (n = 21) and ribonucleic-acid-sequencing data GSE118553 dataset AD patients (n = 21) and HCs (n = 13) were obtained from the gene expression omnibus database before a comprehensive DNAm-transcriptome profile association analysis, and we performed functional enrichment analysis by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses (KEGG). Three transgenic mice and three wild-type mice were used to validate the hub genes.

Results

A total of 18,104 DNAm sites in healthy controls (n = 21) and AD patients (n = 54) were surveyed across three brain regions (superior temporal gyrus, entorhinal cortex, and dorsolateral prefrontal cortex). With the addition of the transcriptome analysis, eight hypomethylated-related highly expressed genes and 61 hypermethylated-related lowly expressed genes were identified. Based on 69 shared differentially methylated genes (DMGs), the function enrichment analysis indicated Guanosine triphosphate enzymes (GTPase) regulator activity, a synaptic vesicle cycle, and tight junction functioning. Following this, mice-based models of AD were constructed, and five hub DMGs were verified, which represented a powerful, disease-specific DNAm signature for AD.

Conclusion

The results revealed that the cross-brain region DNAm was altered in those with AD. The alterations in DNAm affected the target gene expression and participated in the key biological processes of AD. The study provides a valuable epigenetic resource for identifying DNAm-based diagnostic biomarkers, developing effective drugs, and studying AD pathogenesis.

DNA Damage Response-Associated Cell Cycle Re-Entry and Neuronal Senescence in Brain Aging and Alzheimer's Disease

Chronological aging is by far the strongest risk factor for age-related dementia and Alzheimer's disease. Senescent cells accumulated in the aging and Alzheimer's disease brains are now recognized as the keys to describing such an association. Cellular senescence is a classic phenomenon characterized by stable cell arrest, which is thought to be applicable only to dividing cells. Emerging evidence indicates that fully differentiated post-mitotic neurons are also capable of becoming senescent, with roles in contributing to both brain aging and disease pathogenesis. The key question that arises is the identity of the upstream triggers and the molecular mechanisms that underly such changes. Here, we highlight the potential role of persistent DNA damage response as the major driver of senescent phenotypes and discuss the current evidence and molecular mechanisms that connect DNA repair infidelity, cell cycle re-entry and terminal fate decision in committing neuronal cell senescence.

Therapeutic Application of Virtual Reality in the Rehabilitation of Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

This review aimed to quantify the effect of therapeutic application of virtual reality (VR) on cognitive function in individuals with mild cognitive impairment (MCI). We searched for randomized controlled trials involving VR in the interventions provided to individuals with MCI. After searching four international electronic databases, we analyzed six studies involving 279 individuals with MCI. RevMan 5.4 was used for quality assessment and quantitative analysis. Therapeutic application of VR in individuals with MCI resulted in a significant improvement in cognitive function (mean difference = -1.46; 95% confidence interval: -2.53 to -0.39; heterogeneity: χ² = 970.56, df = 18, I² = 98%; and overall effect: Z = 2.67, p = 0.008). However, there was no significant improvement in the subcategories such as global cognition, working memory, executive function, memory function, and attention. In conclusion, feedback stimulation through VR has a potential value in improving cognitive function in individuals with MCI. However, on the basis of the results of the subcategories, a personalized VR program is required for the individual subcategories of cognitive function.

Long-Term Intensive Care Unit (ICU) Stays Can Lead to Long-Term Cognitive Impairment (LTCI): Neurosurgery Nursing Strategies to Minimize Risk

Long-term cognitive impairment (LTCI) is a phenomenon predominantly seen in patients within intensive care units (ICU) that causes chronic dysfunction, defined as new or worsening deficits in memory, attention, mental processing speed, executive function, intellectual function, and visual-spatial abilities for over 12 months, inhibiting the necessary return to baseline function without appropriate intervention. Our objective is to provide a guideline of nursing strategies to reduce LTCI through different studies that evaluate pharmacological and non-pharmacological methods. Current literature demonstrates that pharmacotherapy focused on neuronal protection as well as robust physical therapy regimens and regulated sleep schedules show promise in strengthening cognitive function and reducing LTCI. Future studies regarding LTCI should focus on the efficacy of specific pharmacological regimens, large-scale assessments of the implementation of physical therapy to reduce LTCI, as well as, specific interventions to reduce the incidence of delirium in the ICU.

Organized Registration for the Assessment of Dementia by the Nationwide General Consortium Toward Effective Treatment (ORANGE) Registry: Current Status and Perspectives of Mild Cognitive Impairment

Background: With increasingly aging societies, a comprehensive strategy for dementia research is important. The Organized Registration for the Assessment of dementia by the Nationwide General consortium toward Effective treatment (ORANGE) Registry is the first longitudinal multicenter prospective trial-ready cohort in Japan. Objective: To establish a large cohort for use in clinical trials and research in Japan. Methods: This registry, based on communities, hospitals, and nursing homes, covers three dementia stages (preclinical, mild cognitive impairment [MCI], and advanced dementia), and includes more than 30 hospitals. We analyzed enrollment and 1-year follow-up data for disease progression. Results: There were 1450 registered patients (649 men, 801 women; mean age, 77.92±6.70 years; mean Mini-Mental State Examination [MMSE] score, 25.19±2.76). The conversion rates from MCI to dementia and MCI to normal were 14.3% and 1.1%, respectively. High Clinical Dementia Rating score (odds ratio [OR] = 11.085, 95% confidence interval [CI]:1.619–75.913, p = 0.014), low MMSE score (OR = 0.835, 95% CI: 0.761–0.917, p <  0.001), high Geriatric Depression Scale score (OR = 1.093, 95% CI: 1.005–1.189, p = 0.038), and low body mass index (OR = 0.895, 95% CI: 0.829–0.967, p = 0.005) at enrollment were significant factors for conversion. Conclusion: The ORANGE MCI Registry is an established registry that facilitates creation of trial-ready cohorts to accelerate promotion of clinical trials with low reversion rates as it originates from a hospital. One-year follow-up analysis suggested assessing various factors for conversion risk. Further analyses will be possible in future with registry expansion. We will continue to refine this registry, including how it can be used more efficiently.

COMbined Exercise Trial (COMET) to improve cognition in older adults: Rationale and methods

Substantial evidence suggests physical exercise may sustain cognitive function and perhaps prevent Alzheimer's Disease (1, 2). Current public health recommendations call for older adults to do at least 150 min a week of aerobic exercise (e.g. walking) and twice a week resistance exercise (e.g. weight lifting) for physical health. Yet, much remains unknown about how these exercise modalities support brain health independently or in combination. The COMbined Exercise Trial (COMET) is designed to test the combined and independent effects of aerobic and resistance training specifically focusing on exercise-related changes in 1) cognitive performance, 2) regional brain volume, 3) physical function, and 4) blood-based factors. To explore these questions, we will enroll 280 cognitively normal older adults, age 65-80 years, into a 52-week community-based exercise program. Participants will be randomized into one of four arms: 1) flexibility/toning- control 2) 150 min of aerobic exercise only, 3) progressive resistance training only, or 4) combined aerobic and progressive resistance training. Outcomes assessed include a comprehensive cognitive battery, blood biomarkers, brain magnetic resonance imaging, physiological biomarkers, cardiorespiratory fitness, physical function, and battery of psychosocial questionnaires is assessed at baseline, 6 and 12-months. COMET will provide rigorous randomized controlled trial data to understand the effects of the most common exercise modalities, and their combination (i.e., the standard public health recommendation), on brain health.

The combined effect of physical activity and fruit and vegetable intake on decreasing cognitive decline in older Taiwanese adults

The factors associated with cognitive decline among older adults include physical activity and fruit and vegetable intake. However, the long-term effects of concomitant physical activity and fruit and vegetable intake are unknown. This 16-year longitudinal study explored the joint effect of mitigating cognitive decline in a cohort of older Taiwanese individuals. Five population-based surveys (Taiwan Longitudinal Survey on Aging [1999–2015]) involving 4440 respondents over 53 years old in 1999 were conducted. Cognitive function was assessed using the Short Portable Mental Status Questionnaire (SPMSQ). The demographic, socioeconomic, health-related, behavioral, and disease status covariates were adjusted in the regression analysis. Trends in cognitive decline were observed over 16 years. The risk of cognitive decline decreased by 63% when high physical activity and high fruit and vegetable intake were combined (odds ratio 0.37; 95% confidence interval 0.23–0.59), indicating a potential combined effect of physical activity and fruit and vegetable intake on mitigating cognitive decline. These personal actions are safe, effective, and economical approaches to health promotion and disease prevention.

The Impact of Alcohol Consumption on Cognitive Impairment in Patients With Diabetes, Hypertension, or Chronic Kidney Disease

To investigate the impact of alcohol use on the risk of cognitive impairment in older adults with chronic illness, we used the Digit Symbol Substitution Test (DSST) to evaluate cognitive function in older adults (≥ 60 years) in the National Health and Nutrition Examination Survey. Participants were categorized as light drinkers, moderate and heavy drinkers. Logistic regression analyses were used to explore associations between cognitive impairment and alcohol drinking in patients with or without diabetes, hypertension, and chronic kidney disease (CKD). Multivariate analysis showed that alcohol heavy drinkers was significantly associated with a higher risk of cognitive impairment in patients with hypertension (aOR 6.089, 95% CI 1.318–28.13) and CKD (aOR 6.324, 95% CI 1.158–34.52) compared with light drinkers. The dose-response analyses revealed that moderate to heavy alcohol use was associated with a higher risk of cognitive decline in patients with diabetes and CKD, heavy drinking increased the risk of cognitive impairment in patients with hypertension. The impacts of alcohol drinking on cognitive impairment are significantly different in patients with different comorbidities.

LONG-REMI: An AI-Based Technological Application to Promote Healthy Mental Longevity Grounded in Reminiscence Therapy

Reminiscence therapy (RT) consists of thinking about one's own experiences through the presentation of memory-facilitating stimuli, and it has as its fundamental axis the activation of emotions. An innovative way of offering RT involves the use of technology-assisted applications, which must also satisfy the needs of the user. This study aimed to develop an AI-based computer application that recreates RT in a personalized way, meeting the characteristics of RT guided by a therapist or a caregiver. The material guiding RT focuses on intangible cultural heritage. The application incorporates facial expression analysis and reinforcement learning techniques, with the aim of identifying the user's emotions and, with them, guiding the computer system that emulates RT dynamically and in real time. A pilot study was carried out at five senior centers in Barcelona and Portugal. The results obtained are very positive, showing high user satisfaction. Moreover, the results indicate that the high frequency of positive emotions increased in the participants at the end of the intervention, while the low frequencies of negative emotions were maintained at the end of the intervention.

The Impact of Genes and Environment on Brain Ageing in Males Aged 51 to 72 Years

Magnetic resonance imaging data are being used in statistical models to predicted brain ageing (PBA) and as biomarkers for neurodegenerative diseases such as Alzheimer's Disease. Despite their increasing application, the genetic and environmental etiology of global PBA indices is unknown. Likewise, the degree to which genetic influences in PBA are longitudinally stable and how PBA changes over time are also unknown. We analyzed data from 734 men from the Vietnam Era Twin Study of Aging with repeated MRI assessments between the ages 51-72 years. Biometrical genetic analyses "twin models" revealed significant and highly correlated estimates of additive genetic heritability ranging from 59 to 75%. Multivariate longitudinal modeling revealed that covariation between PBA at different timepoints could be explained by a single latent factor with 73% heritability. Our results suggest that genetic influences on PBA are detectable in midlife or earlier, are longitudinally very stable, and are largely explained by common genetic influences.

The impact of heavy alcohol consumption on cognitive impairment in young old and middle old persons

Background

Dementia indicates a significant disease burden worldwide with increased population aging. This study aimed to investigate the impact of alcohol consumption on the risk of cognitive impairment in older adults.

Methods

Participants ≥ 60 years were administered the Digit Symbol Substitution Test (DSST) to evaluate cognitive function in National Health and Nutrition Examination Survey (NHANES) cycles from 1999 to 2002 and 2011 to 2014 for enrollment in the present study. Participants were categorized into non-drinker, drinker, and heavy drinker groups. Logistic regression analyses were performed to explore associations between cognitive impairment and alcohol consumption.

Results

Multivariate analysis showed that older adults, men, people from minority races, persons with lower education or income levels, social difficulties, hypertension, or chronic kidney disease were significantly associated with a higher risk of cognitive impairment (all p < 0.05). In the young old (60–69 years), heavy amount of alcohol drinking was significantly associated with lower risk of cognitive impairment compared with drinkers [adjusted odds ratio (aOR): 0.280, 95% Confidence interval (CI) 0.095–0.826]. But in the middle old persons (≥ 70 years), heavy alcohol drinking was associated with higher risk of cognitive impairment (aOR: 2.929, 95% CI 0.624–13.74).

Conclusions

Our study demonstrated that light to heavy drinking was associated with lower risk of cognitive impairment in participants aged between 60 and 69 years, but caution is needed in the middle old people with heavy alcohol drinking.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03353-3.

Distinctive effects of executive dysfunction and loss of learning/memory abilities on resting-state brain activity

Dementia is a syndrome characterised by cognitive impairments, with a loss of learning/memory abilities at the earlier stages and executive dysfunction at the later stages. However, recent studies have suggested that impairments in both learning/memory abilities and executive functioning might co-exist. Cognitive impairments have been primarily evaluated using neuropsychological assessments, such as the Mini-Mental State Examination (MMSE). Recently, neuroimaging techniques such as magnetoencephalography (MEG), which assess changes in resting-state brain activity, have also been used as biomarkers for cognitive impairment. However, it is unclear whether these changes reflect dysfunction in executive function as well as learning and memory. In this study, parameters from the MEG for brain activity, MMSE for learning/memory, and Frontal Assessment Battery (FAB) for executive function were compared within 207 individuals. Three MEG parameters were used as representatives of resting-state brain activity: median frequency, individual alpha frequency, and Shannon’s spectral entropy. Regression analysis showed that median frequency was predicted by both the MMSE and FAB scores, while individual alpha frequency and Shannon’s spectral entropy were predicted by MMSE and FAB scores, respectively. Our results indicate that MEG spectral parameters reflect both learning/memory and executive functions, supporting the utility of MEG as a biomarker of cognitive impairment.

A Systematic Review of the Impact of Physical Exercise-Induced Increased Resting Cerebral Blood Flow on Cognitive Functions

Brain perfusion declines with aging. Physical exercise represents a low-cost accessible form of intervention to increase cerebral blood flow; however, it remains unclear if exercise-induced amelioration of brain perfusion has any impact on cognition. We aimed to provide a state-of-the art review on this subject. A comprehensive search of the PubMed (MEDLINE) database was performed. On the basis of the inclusion and exclusion criteria, 14 studies were included in the analysis. Eleven of the studies conducted well-controlled exercise programs that lasted 12–19 weeks for 10–40 participants and two studies were conducted in much larger groups of subjects for more than 5 years, but the exercise loads were indirectly measured, and three of them were focused on acute exercise. Literature review does not show a direct link between exercise-induced augmentation of brain perfusion and better cognitive functioning. However, in none of the reviewed studies was such an association the primary study endpoint. Carefully designed clinical studies with focus on cognitive and perfusion variables are needed to provide a response to the question whether exercise-induced cerebral perfusion augmentation is of clinical importance.

Cognitive impairment and World Trade Centre-related exposures

On 11 September 2001 the World Trade Center (WTC) in New York was attacked by terrorists, causing the collapse of multiple buildings including the iconic 110-story 'Twin Towers'. Thousands of people died that day from the collapse of the buildings, fires, falling from the buildings, falling debris, or other related accidents. Survivors of the attacks, those who worked in search and rescue during and after the buildings collapsed, and those working in recovery and clean-up operations were exposed to severe psychological stressors. Concurrently, these 'WTC-affected' individuals breathed and ingested a mixture of organic and particulate neurotoxins and pro-inflammogens generated as a result of the attack and building collapse. Twenty years later, researchers have documented neurocognitive and motor dysfunctions that resemble the typical features of neurodegenerative disease in some WTC responders at midlife. Cortical atrophy, which usually manifests later in life, has also been observed in this population. Evidence indicates that neurocognitive symptoms and corresponding brain atrophy are associated with both physical exposures at the WTC and chronic post-traumatic stress disorder, including regularly re-experiencing traumatic memories of the events while awake or during sleep. Despite these findings, little is understood about the long-term effects of these physical and mental exposures on the brain health of WTC-affected individuals, and the potential for neurocognitive disorders. Here, we review the existing evidence concerning neurological outcomes in WTC-affected individuals, with the aim of contextualizing this research for policymakers, researchers and clinicians and educating WTC-affected individuals and their friends and families. We conclude by providing a rationale and recommendations for monitoring the neurological health of WTC-affected individuals.

Statistical optimization and formulation of microalga cultivation medium for improved omega 3 fatty acid production

Microalgae are considered a rich source of high-value metabolites with an array of nutraceutical and pharmaceutical applications. Different strategies have been developed for cultivating microalgae at large-scale photobioreactors but high cost and low productivity are the major hurdles. Optimizing the composition of media for the cultivation of microalgae to induce biomass production and high-value metabolite accumulation has been considered as an important factor for sustainable product development. In this study, the effect of plant growth regulators together with basal microalgal cultivation medium on biomass, total lipid, and EPA production was studied using the Plackett-Burman model and Response surface methodology. The traditional one-factor-at-a-time optimization approach is laborious, time-consuming, and requires more experiments which makes the process and analysis more difficult. The Designed PB model was found to be significant for biomass (396 mg/L), lipid (254 mg/L), and EPA (5.6%) production with a P value < 0.05. The major objective of this study is to formulate a medium for EPA production without compromising the growth properties. Further, we had formulated a new media using RSM to achieve the goal and the significant variables selected were NaNO3, NaH2PO4, and IAA and was found to be significant with 16.72% EPA production with a biomass production of 893 mg/L with a P value < 0.05. The formulated medium can be used in large-scale cultivation systems which can enhance biomass production as well as the omega 3 fatty acid production in marine microalgae Nannochloropsis oceanica.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43393-021-00069-1.

Delirium and other neuropsychiatric manifestations of COVID-19 infection in people with preexisting psychiatric disorders: a systematic review

BACKGROUND

Psychiatric disorders increase risk of neuropsychiatric disease and poor outcomes, yet little is known about the neuropsychiatric manifestations of COVID-19 in the psychiatric population. The primary objective is to synthesize neuropsychiatric outcomes of COVID-19 in people with preexisting psychiatric disorders.

METHODS

Data were collected during an ongoing review of the impact of pandemics on people with existing psychiatric disorders. All study designs and gray literature were included. Medline, PsychInfo, CINAHL, EMBASE, and MedRx were searched from inception to September 1 2020. Risk of bias was assessed using a published tool that can accommodate all study types. Two independent authors screened the studies and extracted data. Data were narratively synthesized, as there were insufficient data to meta-analyze. Evidence was appraised according to GRADE.

RESULTS

Four case reports were included, comprising 13 participants from three countries. Many large-sample, relevant papers were omitted for not reporting psychiatric history, despite reporting other comorbidities. Included participants (n = 13) were hospitalized with COVID-19 and appeared to meet criteria for delirium. Myoclonus, rigidity, and alogia were also reported. The most commonly reported preexisting psychiatric diagnoses were mood disorders, schizophrenia, and alcohol use disorder.

CONCLUSIONS

People with preexisting psychiatric disorders may experience delirium, rigidity, myoclonus, and alogia during COVID-19 infection; although higher quality and longitudinal data are needed to better understand these phenomena. Relevant COVID-19 literature does not always report psychiatric history, despite heightened neuropsychiatric vulnerability within this population.

TRIAL REGISTRATION

 PROSPERO (CRD42020179611).

Cognitive reserve, modifiable-risk-factor profile and incidence of dementia: results from a longitudinal study of CFAS Wales

OBJECTIVES

Both cognitive reserve and modifiable-risk-factor profiles play a role in dementia incidence. We investigated whether cognitive reserve moderates the risk of dementia attributable to the modifiable-risk-factor profile.

METHOD

We followed 2102 older individuals aged 65+ years recruited from the population-based longitudinal cohort CFAS Wales study, begun in 2011, and the follow-up wave completed in early 2016. Cognitive reserve was measured by combining educational level, occupation complexity, and engagement in social and cognitive activities in later life. Modifiable-risk-factor profile scores were based on depression, diabetes, smoking, physical activity, healthy diet, and drinking. The interactions between cognitive reserve indicators and modifiable-risk-factor profiles were assessed on multiplicative and additive scales.

RESULTS

There is an additive interaction between the composite effect of cognitive reserve indicator and modifiable-risk-factor profile on dementia. In those with low cognitive reserve, the risk of dementia in participants with a favorable profile was significantly lower than in those with an unfavorable one (OR = 0.08, 95% CI = 0.02-0.27).

CONCLUSION

Cognitive reserve significantly moderates the association between modifiable-risk-factor profiles and dementia.

Working life job strain status and cognitive aging in Europe: A 12-year follow-up study

BACKGROUND

To examine the association of job strain with cognitive ability and the influence of life-course job strain on later life cognitive decline.

METHODS

Data were derived from six waves of the Survey of Health, Aging, and Retirement in Europe. The study sample consists of 13349 participants aged 50 to 98 years at wave 2 and has been followed up for 12-years. Job strain status across working life was assessed using a short demand-control job strain model containing two core dimensions: job demands and job control collected in wave 3. Cognitive abilities concerning episodic memory was assessed by immediate recall and delayed recall tests, executive function was evaluated by verbal fluency test collected in all waves (waves 2-7) except wave 3. Mixed-effects model was used to estimate working life job strain and its cumulative effect on cognitive decline.

RESULTS

Both passive and high strain jobs were associated with lower levels of cognitive ability (episodic memory and verbal fluency) in comparison with active job. Long exposure to active- or low strain-job was associated with higher cognitive ability whereas long exposure to passive job or moderate duration of high strain job was associated with lower cognitive ability. The rate of memory decline was positively related to moderate duration of passive job and negatively related to long-term exposure to low strain job.

LIMITATIONS

Information on working conditions was based on self-reported recollections.

CONCLUSIONS

Working life variation in job strain status and their duration may explain individual differences in cognitive ability in later life.

Impaired Cognitive Function is Associated with Motor Function and Activities of Daily Living in Mild to Moderate Alzheimer's Dementia

BACKGROUND

The deterioration of cognitive and motor functions and activities of daily living is common in Alzheimer's dementia.

OBJECTIVES

The purpose of this study was to investigate the correlation and the strength of the relationship between cognitive function and motor function and activities of daily living after a diagnosis of Alzheimer's disease dementia.

METHODS

Sixty-three patients with mild to moderate Alzheimer's disease dementia in a community setting of South Korea were examined for cognitive and motor functions, and functional levels. The test or measures used for cognitive function were the Mini-Mental State Examination (MMSE), Global Deterioration Scale (GDS), and Clinical Dementia Rating (CDR). The 10-meter walking test (10MWT), Berg Balance Scale (BBS), and Timed Up and Go Test (TUG) were used to examine motor function, while the Modified Barthel Index (MBI) and Katz Index (KI) were used to examining activities of daily living.

RESULTS

The MMSE had a positive correlation with that from the BBS (r=.338, p<.05), MBI (r=.363, p<.05), and KI (r=.276, p<.05). The GDS was negatively correlated with BBS (r=.319, p<.05). Multivariate regression analysis showed that MMSE was a major explanatory variable for BBS (R2 =.115, β=.338, p<.05) MBI (R2 =.131, β=.363, p<.05), and KI (R2 =.076, β=.276, p<.05).

CONCLUSION

The results of the present study show that cognitive function by MMSE is correlated with balance by BBS and activities of daily living by MBI and KI, and MMSE, which are tests or measures for cognitive function, can be explanatory variable to explain variations in the BBS, MBI, and KI in the persons with mild to moderate Alzheimer's dementia. It may mean that a decrease in cognitive function was found to affect motor function and activities of daily living. Based on this study, appropriate intervention approaches including physical exercise, should be considered for caring for persons with mild to moderate Alzheimer's dementia in a community setting.

A Traditional Review of Sickle Cell Disease and the Associated Onset of Dementia: Hematological and Neurocognitive Crossroads

Sickle cell trait and disease are potential risk factors for dementia and cognitive dysfunction in African Americans, as are genetic variants. This illness affects around 300 million people globally. Due to its ability to defend against severe malaria, it represents an evolutionary survival advantage. It has been shown that sickle cell disease and trait are independent risk factors for the prevalence and incidence of albuminuria and chronic renal disease. Sickle cell anemia impairs cognitive performance in people with minimal or mild manifestations of the genetic blood disorder, owing mostly to its cerebrovascular implications. Similarly, various cerebral minor vascular disorders, such as silent cerebral infarcts, have been linked to the sickle cell trait, which is associated with impaired cognitive ability. It has been found that patients with sickle cell disease have a significantly decreased subcortical and cortical brain volume. Adults and children with sickle cell disease have been documented to have attention-related issues, particularly reduced sustained attention.

Predictors of Cognitive Function in Community-Dwelling Older Adults by Age Group: Based on the 2017 National Survey of Older Korean Adults

Owing to a growing older adult population, dementia is emerging as an important health issue. Given that maintaining cognitive functions is crucial for the prevention of dementia, this study aimed to identify the predictors of cognitive function in community-dwelling older adults, through a secondary data analysis of the 2017 National Survey of Older Koreans. A total of 9836 participants were classified into three age groups—young-old (65–74 years), old-old (75–84 years), and oldest-old (≥85 years)—and were separately analyzed using multiple linear regression models. The final model explained 28.0%, 35.0%, and 37.0% of variance in cognitive function in the three age groups, respectively. The most potent predictors of cognitive function in the young-old were electronic device-based activities, instrumental activities of daily living (IADL), and nutrition management; the predictors for the old-old group were electronic device-based activities, IADL, and dementia screening, and those for the oldest-old group were frequency of contact with acquaintances, traveling, and religion. Thus, age group-specific interventions are needed to effectively promote cognitive function among older adults. Digital literacy education, use of community-based elderly welfare programs, opportunities for social interactions, and physical activities can help older adults in maintaining a functional status and muscle strengthening.

Subjective age, depressive symptoms, and cognitive functioning across five domains

Objective: Younger subjective age predicts better episodic memory and executive functioning performance independent of chronological age. This study examined whether subjective age is associated with performance in five cognitive domains, quantified the extent to which these relationships are mediated by depressive symptoms, and tested whether these associations are moderated by chronological age.Method: Participants in this cross-sectional study included 993 adults aged 65 and older from the Health and Retirement Study's 2016 Harmonized Cognitive Assessment Protocol. Moderated mediation models estimated direct and indirect effects of subjective age on factor scores representing episodic memory, executive functioning, language, visuoconstruction, and speed through depressive symptoms and tested whether associations differed according to chronological age.Results: Depressive symptoms explained 21-32% of the associations between subjective age and language, speed, episodic memory, and executive functioning. Chronological age moderated the indirect effect involving language, such that depressive symptoms were more strongly related to worse language performance at older chronological ages. After accounting for indirect effects, direct effects of younger subjective age remained for language and speed domains.Conclusions: This study extends research on the cognitive correlates of subjective age and demonstrates that depressive symptoms partly mediate these relationships. Subjective age may bemost strongly associated with language among individuals at older chronological ages not because they are more sensitive to the negative mental health impact of feeling older than they are but because they may be particularly vulnerable to the negative effects of depressive symptoms on language ability. Additional longitudinal research is needed to determine whether links between subjective age and cognition are causal versus predictive.

Increased Plasma Level of 24S-Hydroxycholesterol and Polymorphism of CYP46A1 SNP (rs754203) Are Associated With Mild Cognitive Impairment in Patients With Type 2 Diabetes

Background

Abnormal cholesterol metabolism is common in type 2 diabetes mellitus (T2DM) and causes dementia. Cholesterol 24S-hydroxylase (CYP46A1) converts cholesterol into 24S-hydroxycholesterol (24-OHC) and maintains cholesterol homeostasis in the brain.

Objective

This study aimed to investigate the roles of 24-OHC and the CYP46A1 (rs754203) polymorphism in patients with T2DM and mild cognitive impairment (MCI).

Methods

A total of 193 Chinese patients with T2DM were recruited into two groups according to the Montreal Cognitive Assessment (MoCA). Demographic and clinical data were collected, and neuropsychological tests were conducted. Enzyme-linked immunosorbent assay (ELISA) and Seqnome method were used to detect the concentration of plasma 24-OHC and the CYP46A1 rs754203 genotype, respectively.

Results

Compared with 118 healthy cognition participants, patients with MCI (n = 75) displayed a higher plasma level of 24-OHC and total cholesterol concentration (all p = 0.031), while no correlation was found between them. In the overall diabetes population, the plasma level of 24-OHC was negatively correlated with MoCA (r = −0.150, p = 0.039), and it was further proved to be an independent risk factor of diabetic MCI (OR = 1.848, p = 0.001). Additionally, patients with MCI and the CC genotype of CYP46A1 rs754203 showed the highest plasma level of 24-OHC even though the difference was not statistically significant, and they obtained low scores in both the verbal fluency test and Stroop color and word test A (p = 0.008 and p = 0.029, respectively).

Conclusion

In patients with T2DM, high plasma level of 24-OHC and the CC genotype carrier of CYP46A1 rs754203 may portend a high risk of developing early cognitive impairment, including attention and executive deficits.

Amyloid-β: A double agent in Alzheimer's disease?

Amyloid-β (Aβ) accumulation is one of the cardinal pathological hallmarks of Alzheimer's disease and plays an important role in its pathogenesis. Although the neurotoxic effects of Aβ has been extensively studied, recent studies have revealed that it may also have protective effects. Here, we review novel findings that have shifted our understanding of the role of Aβ in the pathogenesis of Alzheimer's disease. An in-depth and comprehensive understanding of Aβ will provide us with a broader perspective on the treatment of Alzheimer's disease.

Interaction between APOE ε4 and dietary protein intake on cognitive decline: A longitudinal cohort study

OBJECTIVE

To exam the association of cognitive decline with APOE ε4 allele carriage and dietary protein intake and investigate whether there is a gene-diet (GxD) interaction of APOE ε4 allele carriage and dietary protein intake on cognitive decline in a nationwide cohort of older adults.

METHODS

A cohort study of participants from Chinese Longitudinal Healthy Longevity Survey was conducted from 2008 to 2014. A total of 3029 participants (mean age of 77.0 years, SD = 9.0; 49.3% were women) was enrolled. We genotyped APOE ε4 allele for each participant and calculated the diversity of dietary protein intake (DDPI) by summing up the frequency of intake of the 6 protein-rich foods (meats, fish, eggs, nuts, dairy products, and bean products). We assessed cognitive function using the Mini-Mental State Examination (MMSE). We used ordinal regression model to estimate the independent and joint effects of APOE ε4 carrier and dietary protein intake on cognitive decline, adjusting for potential confounders of age, sex, education, socio-economic status, lifestyles, BMI, and cardiometabolic conditions.

RESULTS

There was significant association between carrying APOE ε4 allele and faster cognitive decline (Odds ratio: 1.19, 95% CI = 1.00-1.42), independent of potential confounders. While the associations of DDPI and the intake of 6 protein-rich foods with cognitive decline did not reach any statistical significance. We observed significant interactions of APOE ε4 with DDPI and fish intake, at multiple correction-adjusted Ps < 0.05. In those who were APOE ε4 carriers rather than non-carriers, both high DDPI (OR = 0.54, 95% CI: 0.34-0.88) and daily fish intake (OR = 0.43, 95% CI: 0.22-0.78) were significantly associated with slower cognitive decline, respectively. We also found that frequent intake of fish benefits women more than men regarding the mitigating of cognitive decline among APOE ε4 allele carriers (P for interaction = 0.016).

CONCLUSIONS

The results of this study support the hypothesis that diversified protein food intake in addition to frequent fish intake may reduce the detrimental effect of APOE ε4 on cognitive health.

Association between dietary diversity and cognitive impairment among the oldest-old: Findings from a nationwide cohort study

BACKGROUND & AIMS

Dietary diversity is widely recommended in national and international guidelines; however, whether the beneficial effects on cognitive function still apply in the oldest-old (80+) has rarely been studied. This study aimed to evaluate the associations of dietary diversity with cognitive function among the oldest-old in a large prospective cohort in China.

METHODS

We conducted a long-term prospective analysis on 11,970 participants aged 80+ (6581 octogenarians, 3730 nonagenarians, and 1659 centenarians). We constructed the baseline dietary diversity score (DDS) based on eight food items of a food frequency questionnaire. Mini-mental state examination (MMSE) was used to classify the participants as having cognitive impairment or not and was also used as a continuous metric. Non-linear associations of DDS with cognitive impairment was evaluated by cox models with penalized splines. We used mixed-effect models for longitudinal data with repeated measurements of MMSE (for up to seven time during the follow-up between 1998 and 2014).

RESULTS

We documented 4778 cognitive impairment during 46,738 person-years of follow-up. Each one unit increase in DDS was associated with a 4% lower risk of cognitive impairment (adjusted hazard ratio (HR): 0.96; 95% confidential interval (CI): 0.94-0.98). Compared to participants with DDS of 0 score, those with a DDS of 1-2, 3-4, and higher than 5 scores had a lower cognitive impairment risk, the HRs were 0.86 (0.79-0.95), 0.82 (0.74-0.91), and 0.72 (0.64-0.82) respectively, and a significant trend emerged (p < 0.001). Compared with DDS of zero score, a DDS of 1-2,3-4, ≥5 was related to slower MMSE decline (β = 0.128, 0.162, 0.301, respectively, p < 0.01).

CONCLUSIONS

Even after the age of 80, dietary diversity may offer a simple and straightforward mean of identifying and screening individuals at high risk for cognitive impairment. Recommendation of dietary diversity may be advocated to attenuate cognitive decline and decrease the risk of cognitive impairment in the oldest-old, especially in a low income or middle-income countries.

APOE-ε4 Carrier Status and Gut Microbiota Dysbiosis in Patients With Alzheimer Disease

BACKGROUND

Alternations in gut microbiota and a number of genes have been implicated as risk factors for the development of Alzheimer disease (AD). However, the interactions between the altered bacteria and risk genetic variants remain unclear.

OBJECTIVE

We aimed to explore associations of the risk genetic variants with altered gut bacteria in the onset of AD.

METHODS

We collected baseline data and stool and blood samples from 30 AD patients and 47 healthy controls in a case-control study. The rs42358/rs4512 (ApoE), rs3851179 (PICALM), rs744373 (BIN1), rs9331888 (CLU), rs670139 (MS4A4E), rs3764650 (ABCA7), rs3865444 (CD33), rs9349407 (CD2AP), rs11771145 (EPHA1), and rs3818361/rs6656401 (CR1) were sequenced, and microbiota composition was characterized using 16S rRNA gene sequencing. The associations of the altered gut bacteria with the risk genetics were analyzed.

RESULTS

Apolipoprotein ε4 allele and rs744373 were risk loci for the AD among 12 genetic variants. Phylum Proteobacteria; orders Enterobacteriales, Deltaproteobacteria, and Desulfovibrionales; families Enterobacteriaceae and Desulfovibrionaceae; and genera Escherichia-Shigella, Ruminococcaceae_UCG_002, Shuttleworthia, Anaerofustis, Morganelia, Finegoldia, and Anaerotruncus were increased in AD subjects, whereas family Enterococcaceae and genera Megamonas, Enterococcus, and Anaerostipes were more abundant in controls (P < 0.05). Among the altered microbiota, APOE ε4 allele was positively associated with pathogens: Proteobacteria.

CONCLUSION

The interaction of APOE ε4 gene and the AD-promoting pathogens might be an important factor requiring for the promotion of AD. Targeting to microbiota might be an effective therapeutic strategy for AD susceptible to APOE ε4 allele. This needs further investigation.