Prevalence of dementia in the United States: the aging, demographics, and memory study

Oxidative stress-mediated neuroinflammation in Alzheimer's disease

Reactive oxygen species (ROS) are metabolic by-products that constitute an indispensable component of physiological processes, albeit their heightened presence may proffer substantial perils to biological entities. Such a proliferation gives rise to a gradual escalation of oxidative stress within the organism, thereby compromising mitochondrial functionality and inflicting harm upon various bodily systems, with a particular predilection for the central nervous system. In its nascent stages, it is plausible that inflammation has been a facilitator in the progression of the malady. The precise role of inflammation in Alzheimer's disease (AD) remains somewhat enigmatic, although it is conceivable that activated microglia and astrocytes might be implicated in the removal of amyloid-β (Aβ) deposits. Nonetheless, prolonged microglial activation is associated with Tau phosphorylation and Aβ aggregation. Research studies have indicated that AD brains upregulate complementary molecules, inflammatory cytokines, acute phase reacting agents, and other inflammatory mediators that may cause neurodegeneration. In this review, oxidative damage products will be discussed as potential peripheral biomarkers for AD and its early stages. The disordered excretion of pro-inflammatory cytokines, chemokines, oxygen, and nitrogen-reactive species, along with the stimulation of the complement system by glial cells, has the potential to disrupt the functionality of neuronal termini. This perturbation, in turn, culminates in compromised synaptic function, a phenomenon empirically linked to the manifestation of cognitive impairments. The management of neurodegenerative conditions in the context of dementia necessitates therapeutic interventions that specifically target the excessive production of inflammatory and oxidative agents. Furthermore, we shall deliberate upon the function of microglia and oxidative injury in the etiology of AD and the ensuing neurodegenerative processes.

Adaptation and Validation of the Psychological Consequences of Screening Questionnaire (PCQ) for Cognitive Screening in Primary Care

BACKGROUND

Context-specific measures with adequate external validity are needed to appropriately determine psychosocial effects related to screening for cognitive impairment.

METHODS

Two-hundred adults aged ≥65 y recently completing routine, standardized cognitive screening as part of their Medicare annual wellness visit were administered an adapted version of the Psychological Consequences of Screening Questionnaire (PCQ), composed of negative (PCQ-Neg) and positive (PCQ-Pos) scales. Measure distribution, acceptability, internal consistency, factor structure, and external validity (construct, discriminative, criterion) were analyzed.

RESULTS

Participants had a mean age of 73.3 y and were primarily female and socioeconomically advantaged. Most had a normal cognitive screening result (99.5%, n = 199). Overall PCQ scores were low (PCQ-Neg: x ¯ = 1.27, possible range 0-36; PCQ-Pos: x ¯ = 7.63, possible range 0-30). Both scales demonstrated floor effects. Acceptability was satisfactory, although the PCQ-Pos had slightly more item missingness. Both scales had Cronbach alphas >0.80 and a single-factor structure. Spearman correlations between the PCQ-Neg with general measures of psychological distress (Impacts of Events Scale-Revised, Perceived Stress Scale, Kessler Distress Scale) ranged from 0.26 to 0.37 (P's < 0.001); the correlation with the World Health Organization-Five Well-Being Index was -0.19 (P < 0.01). The PCQ-Neg discriminated between those with and without a self-reported subjective cognitive complaint (x ¯ = 2.73 v. 0.89, P < 0.001) and was associated with medical visit satisfaction (r = -0.24, P < 0.001) on the Patient Satisfaction Questionnaire. The PCQ-Pos predicted self-reported willingness to engage in future screening (x ¯ = 8.00 v. 3.00, P = 0.03).

CONCLUSIONS

The adapted PCQ-Neg is an overall valid measure of negative psychological consequences of cognitive screening; findings for the PCQ-Pos were more variable. Future studies should address measure performance among diverse samples and those with abnormal screening results.

HIGHLIGHTS

The PCQ scale is an overall valid measure of psychological dysfunction related to cognitive screening in older adults receiving normal screen results.PCQ scale performance should be further validated in diverse populations and those with abnormal cognitive screening results.The adapted PCQ may be useful to both health research and policy stakeholders seeking improved assessment of psychological impacts of cognitive screening.

The association between preserved ratio impaired spirometry (PRISm) and cognitive function among American older adults: the mediating role of systolic blood pressure

BACKGROUND

Recent studies have drawn attention to the association between preserved ratio impaired spirometry (PRISm) and cognitive function decline. High systolic blood pressure (SBP) is a known risk factor for both PRISm and dementia. This study aimed to investigate whether elevated SBP may mediate the relationship between PRISm and cognitive function in older adults.

METHODS

This study analyzed 732 participants aged ≥ 60 years who had completed spirometry and cognitive function tests in the National Health and Nutrition Examination Survey (NHANES) 2011-2012. Multivariable linear regression was employed to assess the relationship between PRISm and cognitive function, as measured through the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word Learning sub-test, the Animal Fluency test (AFT), the Digit Symbol Substitution test (DSST), and global cognition tests. All cognitive tests were modeled as z-scores, and global cognition was calculated as the sum of the z-scores of the CERAD, AFT, and DSST. Mediation analyses were conducted to test the mediating effect of SBP on the association between PRISm and cognitive function.

RESULTS

Participants with PRISm had lower AFT (β = -0.300; 95% confidence interval [CI] = -0.479 to -0.122; p = 0.001), DSST (β = -0.157; 95% CI = -0.309 to -0.004; p = 0.044), and global cognition scores (β = -0.211; 95% CI = -0.369 to -0.053; p = 0.009) than those with normal spirometry, after adjusting for all potential confounders. SBP was considerably associated with AFT (β = -0.084; 95% CI = -0.162 to -0.005; p = 0.038) and DSST (β = -0.132; 95% CI = -0.207 to -0.057; p < 0.001), mediating 7.9% and 18.0% of the association of PRISm with cognitive function, respectively. Furthermore, SBP mediated 17.1% of the association of PRISm with global cognition.

CONCLUSIONS

The findings suggested the potential role of SBP as a mediator of associations between PRISm and cognitive decline in older adults.

Nicotine is an Immunosuppressant: Implications for Women's Health and Disease

A plethora of evidence supports that nicotine, the primary alkaloid in tobacco products that is generally accepted for maintaining use, is immunoregulatory and may function as an immunosuppressant. Women have unique experiences with use of nicotine-containing products and also undergo significant reproductive transitions throughout their lifespan which may be impacted by nicotine use. Within the extant literature, there is conflicting evidence that nicotine may confer beneficial health effects in specific disease states (e.g., in ulcerative colitis). Use prevalence of nicotine-containing products is exceptionally high in individuals presenting with some comorbid disease states that impact immune system health and can be a risk factor for the development of diseases which disproportionately impact women; however, the mechanisms underlying these relationships are largely unclear. Further, little is known regarding the impacts of nicotine's immunosuppressive effects on women's health during the menopausal transition, which is arguably an inflammatory event characterized by a pro-inflammatory peri-menopause period. Given that post-menopausal women are at a higher risk than men for the development of neurodegenerative diseases such as Alzheimer's disease and are also more vulnerable to negative health effects associated with diseases such as HIV-1 infection, it is important to understand how use of nicotine-containing products may impact the immune milieu in women. In this review, we define instances in which nicotine use confers immunosuppressive, anti-inflammatory, or pro-inflammatory effects in the context of comorbid disease states, and focus on how nicotine impacts neuroimmune signaling to maintain use. We posit that regardless of potential health benefits, nicotine use cessation should be a priority in the clinical care of women. The synthesis of this review demonstrates the importance of systematically defining the relationships between volitional nicotine use, immune system function, and comorbid disease states in women to better understand how nicotine impacts women's health and disease.

Trends in prevalence, mortality, and risk factors of dementia among the oldest-old adults in the United States: the role of the obesity epidemic

The oldest-old population, those aged ≥ 80 years, is the fastest-growing group in the United States (US), grappling with an increasingly heavy burden of dementia. We aimed to dissect the trends in dementia prevalence, mortality, and risk factors, and predict future levels among this demographic. Leveraging data from the Global Burden of Disease Study 2019, we examined the trends in dementia prevalence, mortality, and risk factors (with a particular focus on body mass index, BMI) for US oldest-old adults. Through decomposition analysis, we identified key population-level contributors to these trends. Predictive modeling was employed to estimate future prevalence and mortality levels over the next decade. Between 1990 and 2019, the number of dementia cases and deaths among the oldest-old in the US increased by approximately 1.37 million and 60,000 respectively. The population growth and aging were highlighted as the primary drivers of this increase. High BMI emerged as a growing risk factor. Females showed a disproportionately higher dementia burden, characterized by a unique risk factor profile, including BMI. Predictions for 2030 anticipate nearly 4 million dementia cases and 160,000 related deaths, with a marked increase in prevalence and mortality anticipated among those aged 80-89. The past 30 years have witnessed a notable rise in both the prevalence and mortality of dementia among the oldest-old in the US, accompanied by a significant shift in risk factors, with obesity taking a forefront position. Targeted age and sex-specific public health strategies that address obesity control are needed to mitigate the dementia burden effectively.

Cognition and Wealth Changes in Mid-to-later Life: A Latent Class Trajectories Approach Using the Health and Retirement Study

ObjectivesTo assess how cognitive trajectories from mid-to-later life relate to wealth change, overall and by mid-life income. Methods: Data were from participants (51-64 years) in the 2000-2018 U.S. Health and Retirement Study who were cognitively healthy at baseline (year 2000; unweighted n = 3821). Longitudinal latent class analyses generated cognitive and wealth trajectories, independently, and multinomial logistic regressions estimated the association between cognitive trajectories and wealth profiles, overall and by median income. Results: We identified three cognitive: cognitively healthy (CH), increasing cognitive impairment (ICI), and increasing dementia (ID) and four wealth profiles: stable wealth loss (SWL), delayed gradual wealth loss (DGWL), stable wealth gain (SWG), and gradual wealth gain (GWG). The ID group had higher probability of being in the SWL group and lower probability of SWG, which was more pronounced in respondents with greater median income. Discussion: Individuals with ID may be vulnerable to wealth loss, particularly for middle-class households.

Racial and ethnic minority representation in dementia risk factor research: a scoping review of cohort studies

BACKGROUND

Despite a potentially greater burden of dementia, racial and ethnic minority populations around the world may be more likely to be excluded from research examining risk factors for incident dementia. We aimed to systematically investigate and quantify racial and ethnic minority representation in dementia risk factor research.

METHODS

We performed a two-stage systematic search of databases-MEDLINE (Ovid SP), Embase (Ovid SP) and Scopus-from inception to March 2021 to identify population-based cohort studies looking at risk factors for dementia incidence. We included cohort studies which were population-based and incorporated a clinical dementia diagnosis.

RESULTS

Out of the 97 identified cohort studies, fewer than half (40 studies; 41%) reported the race or ethnicity of participants and just under one-third (29 studies; 30%) reported the inclusion of racial and ethnic minority groups. We found that inadequate reporting frequently prevented assessment of selection bias and only six studies that included racial and ethnic minority participants were at low risk for measurement bias in dementia diagnosis. In cohort studies including a multiethnic cohort, only 182 out of 337 publications incorporated race or ethnicity in data analysis-predominantly (90%) through adjustment for race or ethnicity as a confounder. Only 14 publications (4.2% of all publications reviewed) provided evidence about drivers of any observed inequalities.

CONCLUSIONS

Racial and ethnic minority representation in dementia risk factor research is inadequate. Comparisons of dementia risk between different racial and ethnic groups are likely hampered by significant selection and measurement bias. Moreover, the focus on 'adjusting out' the effect of race and ethnicity as a confounder prevents understanding of underlying drivers of observed inequalities. There is a pressing need to fundamentally change the way race, ethnicity and the inclusion of racial and ethnic minorities are considered in research if health inequalities are to be adequately addressed.

Functional Connectome Controllability in Patients with Mild Cognitive Impairment after Repetitive Transcranial Magnetic Stimulation of the Dorsolateral Prefrontal Cortex

Background: Repetitive transcranial magnetic stimulation (rTMS) has shown therapeutic effects in neurological patients by inducing neural plasticity. In this pilot study, we analyzed the modifying effects of high-frequency (HF-)rTMS applied to the dorsolateral prefrontal cortex (DLPFC) of patients with mild cognitive impairment (MCI) using an advanced approach of functional connectome analysis based on network control theory (NCT). Methods: Using local-to-global functional parcellation, average and modal controllability (AC/MC) were estimated for DLPFC nodes of prefrontal-lateral control networks (R/LH_Cont_PFCl_3/4) from a resting-state fMRI series acquired at three time points (T0 = baseline, T1 = T0 + 4 weeks, T2 = T1 + 20 weeks) in MCI patients receiving regular daily sessions of 10 Hz HF-rTMS (n = 10, 68.00 ± 8.16 y, 4 males) or sham (n = 10, 63.80 ± 9.95 y, 5 males) stimulation, between T0 and T1. Longitudinal (group) effects on AC/MC were assessed with non-parametric statistics. Spearman correlations (ρ) of AC/MC vs. neuropsychological (RBANS) score %change (at T1, T2 vs. T0) were calculated. Results: AC median was reduced in MCI-rTMS, compared to the control group, for RH_Cont_PFCl_3/4 at T1 and T2 (vs. T0). In MCI-rTMS patients, for RH_Cont_PFCl_3, AC % change at T1 (vs. T0) was negatively correlated with semantic fluency (ρ = -0.7939, p = 0.045) and MC % change at T2 (vs. T0) was positively correlated with story memory (ρ = 0.7416, p = 0.045). Conclusions: HF-rTMS stimulation of DLFC nodes significantly affects the controllability of the functional connectome in MCI patients. Emerging correlations between AC/MC controllability and cognitive performance changes, immediately (T1 vs. T0) and six months (T2 vs. T0) after treatment, suggest NCT could help explain the HF-rTMS impact on prefrontal-lateral control network, monitoring induced neural plasticity effects in MCI patients.

Chromosome X-wide association study in case control studies of pathologically confirmed Alzheimer's disease in a European population

Although there are several genome-wide association studies available which highlight genetic variants associated with Alzheimer's disease (AD), often the X chromosome is excluded from the analysis. We conducted an X-chromosome-wide association study (XWAS) in three independent studies with a pathologically confirmed phenotype (total 1970 cases and 1113 controls). The XWAS was performed in males and females separately, and these results were then meta-analysed. Four suggestively associated genes were identified which may be of potential interest for further study in AD, these are DDX53 (rs12006935, OR = 0.52, p = 6.9e-05), IL1RAPL1 (rs6628450, OR = 0.36, p = 4.2e-05; rs137983810, OR = 0.52, p = 0.0003), TBX22 (rs5913102, OR = 0.74, p = 0.0003) and SH3BGRL (rs186553004, OR = 0.35, p = 0.0005; rs113157993, OR = 0.52, p = 0.0003), which replicate across at least two studies. The SNP rs5913102 in TBX22 achieves chromosome-wide significance in meta-analysed data. DDX53 shows highest expression in astrocytes, IL1RAPL1 is most highly expressed in oligodendrocytes and neurons and SH3BGRL is most highly expressed in microglia. We have also identified SNPs in the NXF5 gene at chromosome-wide significance in females (rs5944989, OR = 0.62, p = 1.1e-05) but not in males (p = 0.83). The discovery of relevant AD associated genes on the X chromosome may identify AD risk differences and similarities based on sex and lead to the development of sex-stratified therapeutics.

Anticholinergic and sedative medication use in older patients with cognitive concerns

BACKGROUND

Anticholinergic (AC) and sedative medications are a risk factor for cognitive impairment. This study sought to characterize AC and sedative use in older patients seen for outpatient neuropsychological evaluation and evaluate their associations with different cognitive domains. We hypothesized that AC and sedative use would be associated with worse attention/processing speed (AP), executive functioning (EF), and memory.

METHODS

We conducted a cross-sectional chart review of 392 patients (mean [M] age = 72 ± 7.7 years, range = 54-91). Medications were characterized by number of AC medications (≥1 on the Anticholinergic Cognitive Burden Scale [ACB]), number of sedative medications, and polypharmacy (≥5 daily medications). Demographically adjusted composites were calculated for AP, EF, and memory. Bivariate Pearson correlations assessed relationships between medication use and cognition. Multivariate linear regressions evaluated significant medication-cognition associations, controlling for total medications, medical comorbidities, and estimated premorbid cognitive functioning.

RESULTS

Polypharmacy was common (80%; n = 314). Most patients (70%; n = 275) used ≥1 sedative medications (range = 0-9). Over half (63%; n = 248) used ≥1 AC drugs (range = 0-7), yet ACB scores were ≤2 in 74% of patients. Sedative use was negatively correlated with AP (r = -0.134, p = 0.008) and EF (r = -0.105, p = 0.04). ACB scores were negatively correlated with AP (r = -0.106, p = 0.037). Sedatives and a priori covariates significantly predicted AP performance (R2 = 0.127, p < 0.001); using more sedative medications was uniquely associated with worse AP (β = -0.426, p = 0.049). No significant associations were found with memory.

CONCLUSION

AC and sedative medications and polypharmacy were prevalent in this sample of older patients. Though both drug classes had negative relationships with AP and EF, sedatives had a particularly negative association with AP. Contrary to our hypotheses, memory was not associated with medication use; however, anticholinergic burden was low within the sample, and AP and EF deficits may masquerade as memory problems.

The Association Between Cardiovascular Disease and Dementia: A Review of Trends in Epidemiology, Risk Factors, Pathophysiologic Mechanisms, and Clinical Implications

With increases in life expectancy and the size of the aging population, cognitive decline and neurodegenerative pathologies are expected to increase in the next few decades. Age-related increases in risk for dementia and cardiovascular disease have been researched widely. Epidemiology trends reveal a predicted increase of neurodegenerative disease to more than 65 million by 2030 in the United States. There are several risk factors for the development of cardiovascular disease that have been widely studied for their impact on dementia; such as: diabetes, hypertension, and hyperlipidemia. Several pathophysiologic mechanisms exist by which cardiovascular disease could impact dementia including cerebral hypoperfusion, reactive oxidative species, and increased cleavage of amyloid precursor protein into amyloid beta plaques and accumulation of neurofibrillary tangles. Emerging evidence also suggests that treatment of cardiovascular disease risk factors could reduce the risk of dementia development. In this review, we seek to examine the relationship between cardiovascular disease and dementia by examining epidemiologic trends, common risk factors, pathophysiologic mechanisms and implications for clinical management.

Experiences managing behavioral symptoms among Latino caregivers of Latino older adults with dementia and memory problems: a qualitative study

BACKGROUND

Latinos are more likely than non-Latino Whites to develop dementia and be prescribed antipsychotics for dementia-related behavioral symptoms. Antipsychotics have significant risks yet are often overprescribed. Our understanding of how Latino caregivers of Latino older adults living with dementia perceive and address behavioral issues is limited, impeding our ability to address the root causes of antipsychotic overprescribing.

METHODS

We interviewed Latino older adults' caregivers and community-based organization workers serving older adults with cognitive impairment (key informants), focusing on the management of behavioral symptoms and experiences with health services.

RESULTS

We interviewed 8 caregivers and 2 key informants. Caregivers were the spouses, children, or grandchildren of the older adult living with cognitive impairment; their ages ranged from 30 to 95. We identified three categories of how caregivers learned about, managed, and coped with behavioral symptoms: caregivers often faced shortcomings with dementia care in the medical system, receiving limited guidance and support; caregivers found community organizations and senior day centers to be lifelines, as they received relevant, timely advice and support, caregivers often devised their own creative strategies to manage behavioral symptoms.

CONCLUSION

In-depth interviews suggest that the healthcare system is failing to provide support for behavioral symptoms from dementia; caregivers of Latino older adults rely on community organizations instead.

A Polysocial Approach in Exploring Racial and Ethnic Differences in Dementia and Cognitive Decline Among U.S. Older Adults: Health and Retirement Study

Background and Objectives

The racial or ethnic disparity in the burden of dementia exists among older adults in the United States, whereas gaps remain in understanding the synergic effect of multiple social determinants of health on diminishing this disparity. We aim to build a polysocial score for dementia and investigate the racial or ethnic difference in dementia risk among older persons with different polysocial score categories.

Research Design and Methods

In this prospective cohort study, we utilized longitudinal data from the Health and Retirement Study in the United States recruiting 6 945 participants aged ≥65 years who had data on 24 social determinants of health in 2006/2008. The dementia status of participants was measured by a modified version of the Telephone Interview of Cognitive Status. The stepwise Cox regression was applied to select social determinants of health associated with incident dementia to construct a polysocial score. The multivariable Poisson model and linear mixed model were utilized to investigate the associations between polysocial score and incident dementia and cognitive decline, respectively.

Results

Eight social determinants of health were used to build the polysocial score. Non-Hispanic Black older participants had a higher incidence rate (incidence rate difference [IRD] = 22.7; 95% confident interval [95% CI] = 12.7-32.8) than non-Hispanic White older adults in the low polysocial score, while this difference was substantially attenuated in the high polysocial score category (IRD = 0.5; 95% CI = -6.4 to -7.5). The cognitive decline of non-Hispanic older Black adults with high polysocial score was 84.6% slower (averaged cognitive decline: non-Hispanic White: -2.4 [95% CI = -2.5 to -2.3] vs non-Hispanic Black: -1.3 [95% CI = -1.9 to -0.8]) than that of non-Hispanic older White persons.

Discussion and Implications

These findings may help comprehensively understand and address racial and ethnic disparities in dementia risk and may be integrated into existing dementia prevention programs to provide targeted interventions for community-dwelling older adults with differentiated social disadvantages.

Trends on Prevalence, All-Cause Mortality, and Survival Status of Dementia Patients in Rural China Based on Pooling Analysis

Objectives

No study has reported secular trends in dementia prevalence, all-cause mortality, and survival status in rural China.

Methods

We established two cohorts (XRRCC1 and XRRCC2) in the same region of China, 17 years apart, to compare dementia prevalence, all-cause mortality, and survival status, and performed regression analysis to identify associated factors.

Results

Dementia prevalence was 3.49% in XRRCC1 and 4.25% in XRRCC2, with XRRCC2 showing a significantly higher prevalence (OR = 1.79, 95%CI: 1.2-2.65). All-cause mortality rates for dementia patients were 62.0% in XRRCC1 and 35.7% in XRRCC2. Mortality in the normal population of XRRCC2 decreased by 66% compared to XRRCC1, mainly due to improved survival rates in women with dementia. Dementia prevalence was positively associated with age >65, spouse-absent status, and stroke, and negatively associated with ≥6 years of education.

Conclusion

Dementia prevalence in rural China increased over 17 years, while mortality decreased. Major risk factors include aging, no spouse, and stroke, with higher education offering some protection.

A comparison of dementia diagnoses and cognitive function measures in Medicare claims and the Minimum Data Set

BACKGROUND

Gold standard dementia assessments are rarely available in large real-world datasets, leaving researchers to choose among methods with imperfect but acceptable accuracy to identify nursing home (NH) residents with dementia. In healthcare claims, options include claims-based diagnosis algorithms, diagnosis indicators, and cognitive function measures in the Minimum Data Set (MDS), but few studies have compared these. We evaluated the proportion of NH residents identified with possible dementia and concordance of these three.

METHODS

Using a 20% random sample of 2018-2019 Medicare beneficiaries, we identified MDS admission assessments for non-skilled NH stays among individuals with continuous enrollment in Medicare Parts A, B, and D. Dementia was identified using: (1) Chronic Conditions Warehouse (CCW) claims-based algorithm for Alzheimer's disease and non-Alzheimer's dementia; (2) MDS active diagnosis indicators for Alzheimer's disease and non-Alzheimer's dementias; and (3) the MDS Cognitive Function Scale (CFS) (at least mild cognitive impairment). We compared the proportion of admissions with evidence of possible dementia using each criterion and calculated the sensitivity, specificity, and agreement of the CCW claims definition and MDS indicators for identifying any impairment on the CFS.

RESULTS

Among 346,013 non-SNF NH admissions between 2018 and 2019, 57.2% met criteria for at least one definition (44.7% CFS, 40.7% CCW algorithm, 26.0% MDS indicators). The MDS CFS uniquely identified the greatest proportion with evidence of dementia. The CCW claims algorithm had 63.7% sensitivity and 78.1% specificity for identifying any cognitive impairment on the CFS. Active diagnosis indicators from the MDS had lower sensitivity (47.0%), but higher specificity (91.0%).

CONCLUSIONS

Claims- and MDS-based methods for identifying NH residents with possible dementia have only partial overlap in the cohorts they identify, and neither is an obvious gold standard. Future studies should seek to determine whether additional functional assessments from the MDS or prescriptions can improve identification of possible dementia in this population.

Nomination of a novel plasma protein biomarker panel capable of classifying Alzheimer's disease dementia with high accuracy in an African American cohort

Introduction

African Americans (AA) are widely underrepresented in plasma biomarker studies for Alzheimer's disease (AD) and current diagnostic biomarker candidates do not reflect the heterogeneity of AD.

Methods

Untargeted proteome measurements were obtained using the SomaScan 7k platform to identify novel plasma biomarkers for AD in a cohort of AA clinically diagnosed as AD dementia (n=183) or cognitively unimpaired (CU, n=145). Machine learning approaches were implemented to identify the set of plasma proteins that yields the best classification accuracy.

Results

A plasma protein panel achieved an area under the curve (AUC) of 0.91 to classify AD dementia vs CU. The reproducibility of this finding was observed in the ANMerge plasma and AMP-AD Diversity brain datasets (AUC=0.83; AUC=0.94).

Discussion

This study demonstrates the potential of biomarker discovery through untargeted plasma proteomics and machine learning approaches. Our findings also highlight the potential importance of the matrisome and cerebrovascular dysfunction in AD pathophysiology.

MIAMI-AD (Methylation in Aging and Methylation in AD): an integrative knowledgebase that facilitates explorations of DNA methylation across sex, aging, and Alzheimer's disease

Alzheimer's disease (AD) is a common neurodegenerative disorder with a significant impact on aging populations. DNA methylation (DNAm) alterations have been implicated in both the aging processes and the development of AD. Given that AD affects more women than men, it is also important to explore DNAm changes that occur specifically in each sex. We created MIAMI-AD, a comprehensive knowledgebase containing manually curated summary statistics from 98 published tables in 38 studies, all of which included at least 100 participants. MIAMI-AD enables easy browsing, querying, and downloading DNAm associations at multiple levels-at individual CpG, gene, genomic regions, or genome-wide, in one or multiple studies. Moreover, it also offers tools to perform integrative analyses, such as comparing DNAm associations across different phenotypes or tissues, as well as interactive visualizations. Using several use case examples, we demonstrated that MIAMI-AD facilitates our understanding of age-associated CpGs in AD and the sex-specific roles of DNAm in AD. This open-access resource is freely available to the research community, and all the underlying data can be downloaded. MIAMI-AD facilitates integrative explorations to better understand the interplay between DNAm across aging, sex, and AD. Database URL: https://miami-ad.org/.

Oral diseases are associated with cognitive function in adults over 60 years old

OBJECTIVE

To investigate the bidirectional association between oral diseases and cognitive function comprehensively.

SUBJECTS AND METHODS

This cross sectional study utilized data from the National Health and Nutrition Examination Survey. Oral diseases include periodontitis, dental caries, and tooth loss (end point of oral disease resulting in tooth extraction). Cognitive function included three domains: memory, processing speed, and executive function. A global cognitive score was then derived from sum of the three cognitive domains. Oral cognition associations were examined using various statistical models: (1) Regress oral disease on cognitive function; (2) Regress cognitive function on oral disease; and (3) Structural equation modelling treating cognition and oral disease as latent variables.

RESULTS

There were 2508 participants aged 60+ who had both oral and cognitive information. Associations between various oral disease and global cognitive score were observed (Odds ratio ORcog->periodontitis 0.95, 95% Confidence Interval [0.92, 0.99]; βcog->caries -0.13, [-0.23, -0.04]; βcog->tooth loss -0.03 [-0.04, -0.01]; βtooth loss->cog -0.04 [-0.06, -0.02]; βcaries->cog -0.03 [-0.06, -0.01]; βperiodontitis->cog -0.39 [-0.69, -0.10]). Significant correlation was also found between these oral disease and cognitive function using structural equation model (r -0.22, [-0.34, -0.10]).

CONCLUSIONS

This study found robust bidirectional associations between oral disease and cognitive function using various modelling approaches among the aging population.

Association of cardiovascular diseases with cognitive performance in older adults

BACKGROUND

Cognitive function and cardiovascular disease (CVD) have a bidirectional relationship, but studies on the impact of CVD subtypes and aging spectrum have been scarce.

METHODS

We assessed older adults aged ≥60 years from the 2011 to 2012 and 2013 to 2014 cycles of the National Health and Nutrition Examination Survey who had coronary heart disease, angina, prior myocardial infarction, congestive heart failure, or prior stroke. We compared CERAD-IR, CERAD-DR, Animal Fluency test, and DSST scores to assess cognitive performance in older adults with and without CVD.

RESULTS

We included 3,131 older adults, representing 55,479,673 older adults at the national level. Older adults with CVD had lower CERAD-IR (mean difference 1.8, 95% CI 1.4-2.1, P < .001), CERAD-DR (mean difference 0.8, 95% CI 0.6-1.0, P < .001), Animal Fluency test (mean difference 2.1, 95% CI 1.6-2.6, P < .001), and DSST (mean difference 9.5, 95% CI 8.0-10.9, P < .001) scores compared with those without CVD. After adjustment, no difference in CERAD-IR, CERAD-DR, and Animal Fluency test scores was observed, but DSST scores were lower in older adults with CVD (adjusted mean difference 2.9, 95% CI 1.1-4.7, P = .001). Across CVD subtypes, individuals with congestive heart failure had lower performance on the DSST score. The oldest-old cohort of patients ≥80 years old with CVD had lower performance than those without CVD on both the DSST and Animal Fluency test.

CONCLUSION

Older adults with CVD had lower cognitive performance as measured than those free of CVD, driven by pronounced differences among those with CHF and those ≥80 years old with CVD.

Dementia severity at incident diagnosis in a population representative sample of older Americans

INTRODUCTION

We provide the first analysis of distribution of dementia severity at incident diagnosis for a population representative sample of older Americans.

METHODS

Using data from the Aging, Demographics, and Memory Study (ADAMS), the Health Retirement Study (HRS), and traditional Medicare claims, we estimated the Clinical Dementia Rating Scale for ADAMS respondents and applied parameter estimates to predict dementia severity for HRS respondents with claims-based incident dementia diagnosis.

RESULTS

Seventy percent of older adults received a dementia diagnosis of mild cognitive impairment or mild dementia (early stages). Fewer individuals were diagnosed at early stages in years 2000 to 2008 (65%) compared to years 2009 to 2016 (76%). About 72% of non-Hispanic white persons were diagnosed at early stages, compared to 63% non-Hispanic black and 59% Hispanic persons. More males than females were diagnosed at early stages (75% vs 67%).

DISCUSSION

These data linkages allow population surveillance of early and equitable dementia detection in the older US population to assess clinical and policy levers to improve detection.

Highlights

For the US population 70 and older, 30% were diagnosed with dementia at a moderate or severe stage.Fewer were diagnosed at early stages in years 2000 to 2008 compared to 2009 to 2016 (65% vs 76%).A total of 72% of white persons were diagnosed at early stages, compared to 63% black and 59% Hispanic persons.More males than females were diagnosed at early stages (75% vs 67%).High wealth and education level were associated with diagnosis at early stages disease.

The African American Dementia and Aging Project (AADAPt): An Oregon-based Longitudinal Study

Objectives

The vast majority of studies on aging, cognition, and dementia focus on non-Hispanic white subjects. This paper adds to the extant literature by providing insight into the African American aging experience. Here we describe the study design and baseline characteristics of the African American Dementia and Aging Project (AADAPt) study, which is exploring aging and cognition in African American older adults in Oregon.

Methods

African American older adults (n=177) participated in AADAPt, a longitudinal study that collected data on cognitive, physical, and social functioning in annual visits since 2000.

Results

AADAPt participants had risk factors for developing dementia in future, such as hypertension and hyperlipidemia, but also reported protective factors such as high social engagement.

Conclusions

The AADAPt project offers new insights into aging in older African Americans that includes data on cognition, social engagement, and physical health, which are crucial for understanding the experience of under-represented groups and making future studies more inclusive. These findings reflect a window of time for a geographically-focused cohort, and the lessons learned from this study likely have broader implications for shaping the health of these older African American adults. Keywords: African American, Dementia, Observational Study.

Acoustic Analysis of Swallowing of an Experimental Meal of Three Food Textures: A Comparative Aging Study

Swallowing disorders in the elderly represent a public health problem, their detections are a medico-economic issue. The acoustic analysis of swallowing has the advantages of being non-invasive with no radiation, compared to videofluoroscopy or fiberoptic swallowing assessments. Acoustic analysis of swallowing has been tested in many studies but only on small food boluses. The aim of this study was to compare the acoustic swallowing parameters of two groups of healthy subjects, before and after 70 years old, during the intake of a series of 3 food textures. A laryngophone was used to record the pharyngeal phase of swallowing. The experimental meal was composed of 100 ml of mashed potatoes, 100 ml of water, and 100 ml of yogurt. Group 1 (50-70 years old) comprised 21 subjects and group 2 (over 70 years old) 23 subjects. Acoustic parameters analyzed were the number of swallows, average duration of swallowing, average duration of inter-swallowing, meal duration, and the average frequency of swallowing per minute. These parameters for groups 1 and 2 were compared. The average duration of inter-swallowing and the meal duration were significantly higher in the older group (p < 0.001), with a mean duration of inter-swallowing that was 2.4 s longer than the younger group. The average swallowing frequency per minute was higher in the younger group (11.3 vs 7.9; p < 0.001). This study demonstrated that acoustic analysis of an experimental meal of three food textures generated usable data on swallowing. In the over 70 age group, there was a decrease in swallowing frequency, indicating a slowdown in food intake. A reduced swallowing frequency could become a criteria to assess presbyphagia.

Comparative Review of the Socioeconomic Burden of Lower Back Pain in the United States and Globally

Internationally, the United States (U.S.) cites the highest cost burden of low back pain (LBP). The cost continues to rise, faster than the rate of inflation and overall growth of health expenditures. We performed a comprehensive literature review of peer-reviewed and non- peer-reviewed literature from PubMed, Scopus, and Google Scholar for contemporary data on prevalence, cost, and projected future costs. Policymakers in the U.S. have long attempted to address the high-cost burden of LBP through limiting low-value services and early imaging. Despite these efforts, costs (~$40 billion; ~$2,000/patient/yr) continue to rise with increasing rates of unindicated imaging, high rates of surgery, and subsequent revision surgery without proper trial of non-pharmacologic measures and no corresponding reduction in LBP prevalence. Globally, the overall prevalence of LBP continues to rise largely secondary to a growing aging population. Cost containment methods should focus on careful and comprehensive clinical assessment of patients to better understand when more resource-intensive interventions are indicated.

Atrial Fibrillation and Cognitive Disorders

The prevalence of atrial fibrillation among older adults is increasing. Research has indicated that atrial fibrillation is linked to cognitive impairment disorders such as Alzheimer and vascular dementia, as well as Parkinson disease. Various mechanisms are believed to be shared between atrial fibrillation and cognitive impairment disorders. The specific pathologies and mechanisms of different cognitive disorders are still being studied. Potential mechanisms include cerebral hypoperfusion, ischemic or hemorrhagic infarction, and cerebrovascular reactivity to carbon dioxide. Additionally, circulatory biomarkers and certain infectious organisms appear to be involved. This review offers an examination of the overlapping epidemiology between atrial fibrillation and cognitive disorders, explores different cognitive disorders and their connections with this arrhythmia, and discusses trials and guidelines for preventing and treating atrial fibrillation in patients with cognitive disorders. It synthesizes existing knowledge on the management of atrial fibrillation and identifies areas that require further investigation to bridge the gap in understanding the complex relationship between dementia and atrial fibrillation.

A Look Into How the "Blue Zone" Lifestyle May Affect Patients' Lives Before and After Hip Fracture: A Propensity-Matched Cohort Study

INTRODUCTION

Hip fractures are life-changing injuries with associated one-year mortality up to 30%. Five locations in the world have been termed "blue zones," where the longevity of the population is markedly higher than that of surrounding areas and there are 10 times more centenarians. The United States has one blue zone (Loma Linda, California), which is believed to be because of the lifestyle of the Seventh-day Adventist population living there. We hypothesized that patients from the blue zone experience low-energy, frailty-driven, osteoporotic hip fractures later in life and an increased postinjury longevity relative to non-blue zone control subjects.

METHODS

A review of patients treated for hip fracture between January 2010 and August 2020 from a single institution was conducted. Demographic data were collected, and the end point of mortality was assessed using death registry information, queried in April 2024. Groups were divided into blue zone and non-blue zone. Statistical analysis was conducted with P < 0.05 considered significant.

RESULTS

Complete data were available for 1,032 patients. The blue zone cohort sustained low-energy hip fractures 12 years later in life (83.2 versus 71.1, P < 0.01). Propensity score matching was used to account for this difference. After propensity score matching, age, body mass index, American Society of Anesthesiologists score, surgery performed, sex, mechanism, ethnicity, diabetes, chronic obstructive pulmonary disease, CHF, chronic kidney disease grade, dementia, surgical time, and drug/tobacco/marijuana use were similar between groups. Blue zone patients had lower mortality at both 1 and 2 years postoperatively (12% versus 24%, P = 0.03 and 20% versus 33%, P = 0.03, respectively), had more hypertension (76% versus 62%, P = 0.03), reported lower alcohol use (7% versus 20%, P < 0.01), and included more Seventh-day Adventists (64% versus 15%, P < 0.01).

CONCLUSION

The blue zone lifestyle affected the onset of frailty and delayed osteoporotic hip fracture by 12 years in this propensity-matched cohort study. Postoperative mortality was also markedly lower in the blue zone cohort.

2024 Alzheimer's disease facts and figures

This article describes the public health impact of Alzheimer's disease (AD), including prevalence and incidence, mortality and morbidity, use and costs of care and the ramifications of AD for family caregivers, the dementia workforce and society. The Special Report discusses the larger health care system for older adults with cognitive issues, focusing on the role of caregivers and non-physician health care professionals. An estimated 6.9 million Americans age 65 and older are living with Alzheimer's dementia today. This number could grow to 13.8 million by 2060, barring the development of medical breakthroughs to prevent or cure AD. Official AD death certificates recorded 119,399 deaths from AD in 2021. In 2020 and 2021, when COVID-19 entered the ranks of the top ten causes of death, Alzheimer's was the seventh-leading cause of death in the United States. Official counts for more recent years are still being compiled. Alzheimer's remains the fifth-leading cause of death among Americans age 65 and older. Between 2000 and 2021, deaths from stroke, heart disease and HIV decreased, whereas reported deaths from AD increased more than 140%. More than 11 million family members and other unpaid caregivers provided an estimated 18.4 billion hours of care to people with Alzheimer's or other dementias in 2023. These figures reflect a decline in the number of caregivers compared with a decade earlier, as well as an increase in the amount of care provided by each remaining caregiver. Unpaid dementia caregiving was valued at $346.6 billion in 2023. Its costs, however, extend to unpaid caregivers' increased risk for emotional distress and negative mental and physical health outcomes. Members of the paid health care and broader community-based workforce are involved in diagnosing, treating and caring for people with dementia. However, the United States faces growing shortages across different segments of the dementia care workforce due to a combination of factors, including the absolute increase in the number of people living with dementia. Therefore, targeted programs and care delivery models will be needed to attract, better train and effectively deploy health care and community-based workers to provide dementia care. Average per-person Medicare payments for services to beneficiaries age 65 and older with AD or other dementias are almost three times as great as payments for beneficiaries without these conditions, and Medicaid payments are more than 22 times as great. Total payments in 2024 for health care, long-term care and hospice services for people age 65 and older with dementia are estimated to be $360 billion. The Special Report investigates how caregivers of older adults with cognitive issues interact with the health care system and examines the role non-physician health care professionals play in facilitating clinical care and access to community-based services and supports. It includes surveys of caregivers and health care workers, focusing on their experiences, challenges, awareness and perceptions of dementia care navigation.

Effect of visual impairment on subjective cognitive decline in older adults: a cross-sectional study in China

OBJECTIVE

People with visual impairment have more functional limitations associated with subjective cognitive decline (SCD), and those with SCD are extremely susceptible to transitioning to irreversible cognitive impairment. This study aimed to explore if visual impairment is a significant predictor of SCD compared with other socioeconomic and health factors associated with SCD.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

The investigation aimed to assess the factors influencing SCD among 428 participants aged 60 and above in Zhaoyuan, China.

PRIMARY OUTCOME MEASURES

The primary outcome variable was SCD, measured by the Chinese version of SCD questionnaire. Multiple logistic regression and propensity score matching (PSM) were used to analyse the influence of visual impairment on the subjective cognition of the elderly.32.2% of the elderly were experiencing SCD. Older adults with SCD showed a higher prevalence of visual impairment (72.5%) than the elderly without SCD (58.6%) (P=0.006). Multivariate logistic regression analysis showed that bad self-reported health status, lack of physical exercise and visual impairment were the risk factors for SCD in older adults, while more than 9 years of education was a protective factor. In addition, PSM model showed that after eliminating the dominant biases caused by the individual observable heterogeneity of older adults with and without visual impairment, the risk of SCD in the elderly with visual impairment was increased by 13.6%-14.5% and the difference was statistically significant (P<0.05).

CONCLUSIONS

It was found that older adults experiencing visual impairments are at an elevated risk of developing SCD compared with their counterparts without such impairments. Additionally, visual impairment remains a significant risk factor for SCD in the elderly, even adjusting for potential biases arising from individual observable heterogeneity.

Data-driven clustering approach to identify novel clusters of high cognitive impairment risk among Chinese community-dwelling elderly people with normal cognition: A national cohort study

Background

Cognitive impairment is a highly heterogeneous disorder that necessitates further investigation into the distinct characteristics of populations at varying risk levels of cognitive impairment. Using a large-scale registry cohort of elderly individuals, we applied a data-driven approach to identify novel clusters based on diverse sociodemographic features.

Methods

A prospective cohort of 6398 elderly people from the Chinese Longitudinal Healthy Longevity Survey, followed between 2008-14, was used to develop and validate the model. Participants were aged ≥60 years, community-dwelling, and the Chinese version of the Mini-Mental State Examination (MMSE) score ≥18 were included. Sixty-nine sociodemographic features were included in the analysis. The total population was divided into two-thirds for the derivation cohort (n = 4265) and one-third for the validation cohort (n = 2133). In the derivation cohort, an unsupervised Gaussian mixture model was applied to categorise participants into distinct clusters. A classifier was developed based on the most important 10 factors and was applied to categorise participants into their corresponding clusters in a validation cohort. The difference in the three-year risk of cognitive impairment was compared across the clusters.

Results

We identified four clusters with distinct features in the derivation cohort. Cluster 1 was associated with the worst life independence, longest sleep duration, and the oldest age. Cluster 2 demonstrated the highest loneliness, characterised by non-marital status and living alone. Cluster 3 was characterised by the lowest sense of loneliness and the highest proportions in marital status and family co-residence. Cluster 4 demonstrated heightened engagement in exercise and leisure activity, along with independent decision-making, hygiene, and a diverse diet. In comparison to Cluster 4, Cluster 1 exhibited the highest three-year cognitive impairment risk (adjusted odds ratio (aOR) = 3.31; 95% confidence interval (CI) = 1.81-6.05), followed by Cluster 2 and Cluster 3 after adjustment for baseline MMSE, residence, sex, age, years of education, drinking, smoking, hypertension, diabetes, heart disease and stroke or cardiovascular diseases.

Conclusions

A data-driven approach can be instrumental in identifying individuals at high risk of cognitive impairment among cognitively normal elderly populations. Based on various sociodemographic features, these clusters can suggest individualised intervention plans.

The association between waist-to-height ratio and cognitive function in older adults

OBJECTIVES

The waist-to-height ratio (WHtR) is a simple, practical, and effective tool used to assess central obesity. Despite its usefulness, few studies have investigated the association between WHtR and cognitive function among older adults in the United States. This study aims to investigate the associations between WHtR and cognitive function.

METHODS

The study sample comprised adults who participated in the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2014. WHtR was calculated from measured waist circumference and height. Cognitive function was assessed using the digit symbol substitution test. A weighted multiple linear regression analysis was performed to evaluate the association between WHtR and cognitive function, with smooth curve fitting applied to detect non-linearities.

RESULTS

Our analysis included 1709 participants over the age of 65. After adjusting for potential confounders, WHtR was found to have a negative association with cognitive function (β = -36.91, 95% CI: -54.54 to -19.29, P < 0.001). Subgroup analyzes stratified by sex and race showed that the negative correlation of WHtR with cognitive function remained in both men and women, as well as in non-Hispanic white and other races. Among women, the association between WHtR and cognitive function followed an inverted U-shaped curve, with an inflection point of 0.68.

CONCLUSION

This study provides evidence of a negative association between WHtR and cognitive function in older adults. These findings suggest that in advanced age, central obesity may have negative implications for cognitive function.

Towards a Deeper Understanding: Utilizing Machine Learning to Investigate the Association between Obesity and Cognitive Decline-A Systematic Review

Background/Objectives: Several studies have shown a relation between obesity and cognitive decline, highlighting a significant global health challenge. In recent years, artificial intelligence (AI) and machine learning (ML) have been integrated into clinical practice for analyzing datasets to identify new risk factors, build predictive models, and develop personalized interventions, thereby providing useful information to healthcare professionals. This systematic review aims to evaluate the potential of AI and ML techniques in addressing the relationship between obesity, its associated health consequences, and cognitive decline. Methods: Systematic searches were performed in PubMed, Cochrane, Web of Science, Scopus, Embase, and PsycInfo databases, which yielded eight studies. After reading the full text of the selected studies and applying predefined inclusion criteria, eight studies were included based on pertinence and relevance to the topic. Results: The findings underscore the utility of AI and ML in assessing risk and predicting cognitive decline in obese patients. Furthermore, these new technology models identified key risk factors and predictive biomarkers, paving the way for tailored prevention strategies and treatment plans. Conclusions: The early detection, prevention, and personalized interventions facilitated by these technologies can significantly reduce costs and time. Future research should assess ethical considerations, data privacy, and equitable access for all.

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.

The advent of Alzheimer treatments will change the trajectory of human aging

Slowing neurodegenerative disorders of late life has lagged behind progress on other chronic diseases. But advances in two areas, biochemical pathology and human genetics, have now identified early pathogenic events, enabling molecular hypotheses and disease-modifying treatments. A salient example is the discovery that antibodies to amyloid ß-protein, long debated as a causative factor in Alzheimer's disease (AD), clear amyloid plaques, decrease levels of abnormal tau proteins and slow cognitive decline. Approval of amyloid antibodies as the first disease-modifying treatments means a gradually rising fraction of the world's estimated 60 million people with symptomatic disease may decline less or even stabilize. Society is entering an era in which the unchecked devastation of AD is no longer inevitable. This Perspective considers the impact of slowing AD and other neurodegenerative disorders on the trajectory of aging, allowing people to survive into late life with less functional decline. The implications of this moment for medicine and society are profound.

Hearing loss and dementia in older adults: A narrative review

The prevalence of hearing loss is high among older adults; globally, 65% of adults over 60 years have hearing loss. Over the past decade, evidence from epidemiologic studies has linked hearing loss to nearly two times greater risk of dementia. The hypothesized mechanistic pathways through which hearing loss could contribute to increased dementia risk include the effects of hearing on greater cognitive load, changes in brain structure and function, and decreased social engagement. These mechanistic pathways may be modified by management of hearing loss using existing intervention (eg, hearing aids). Hearing treatment may be an effective intervention for slowing cognitive decline in some older adults. In this review, we update existing reviews of the current epidemiologic research on the association between hearing loss and dementia risk and discuss hypothesized mechanisms of this association. We also discuss management of hearing loss as a potential intervention for slowing cognitive decline and reducing dementia risk.

Development and validation of a cognitive dysfunction risk prediction model for the abdominal obesity population

Objectives

This study was aimed to develop a nomogram that can accurately predict the likelihood of cognitive dysfunction in individuals with abdominal obesity by utilizing various predictor factors.

Methods

A total of 1490 cases of abdominal obesity were randomly selected from the National Health and Nutrition Examination Survey (NHANES) database for the years 2011-2014. The diagnostic criteria for abdominal obesity were as follows: waist size ≥ 102 cm for men and waist size ≥ 88 cm for women, and cognitive function was assessed by Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Word Learning subtest, Delayed Word Recall Test, Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST). The cases were divided into two sets: a training set consisting of 1043 cases (70%) and a validation set consisting of 447 cases (30%). To create the model nomogram, multifactor logistic regression models were constructed based on the selected predictors identified through LASSO regression analysis. The model's performance was assessed using several metrics, including the consistency index (C-index), the area under the receiver operating characteristic (ROC) curve (AUC), calibration curves, and decision curve analysis (DCA) to assess the clinical benefit of the model.

Results

The multivariate logistic regression analysis revealed that age, sex, education level, 24-hour total fat intake, red blood cell folate concentration, depression, and moderate work activity were significant predictors of cognitive dysfunction in individuals with abdominal obesity (p < 0.05). These predictors were incorporated into the nomogram. The C-indices for the training and validation sets were 0.814 (95% CI: 0.875-0.842) and 0.805 (95% CI: 0.758-0.851), respectively. The corresponding AUC values were 0.814 (95% CI: 0.875-0.842) and 0.795 (95% CI: 0.753-0.847). The calibration curves demonstrated a satisfactory level of agreement between the nomogram model and the observed data. The DCA indicated that early intervention for at-risk populations would provide a net benefit, as indicated by the line graph.

Conclusion

Age, sex, education level, 24-hour total fat intake, red blood cell folate concentration, depression, and moderate work activity were identified as predictive factors for cognitive dysfunction in individuals with abdominal obesity. In conclusion, the nomogram model developed in this study can effectively predict the clinical risk of cognitive dysfunction in individuals with abdominal obesity.

CRISPR/Cas9 Gene Editing: A Novel Approach Towards Alzheimer's Disease Treatment

In defiance of the vast amount of information regarding Alzheimer's disease (AD) that has been learned over the past thirty years, progress toward developing an effective therapy has been difficult. A neurological ailment that progresses and cannot be reversed is Alzheimer's disease, which shows neurofibrillary tangles, beta-amyloid plaque, and a lack of cognitive processes that is created by tau protein clumps with hyperphosphorylation that finally advances to neuronal damage without a recognized treatment, which has stimulated research into new therapeutic strategies. The protein CAS9 is linked to CRISPR, which is a clustered Regularly Interspaced Short Palindromic Repeat that inactivates or corrects a gene by recognizing a gene sequence that produces a doublestranded break has enchanted a whole amount of interest towards its potency to cure gene sequences in AD. The novel CRISPR-Cas9 applications for developing in vitro and in vivo models to the benefit of AD investigation and therapies are thoroughly analyzed in this work. The discussion will also touch on the creation of delivery methods, which is a significant obstacle to the therapeutic use of CRISPR/Cas9 technology. By concentrating on specific genes, such as those that are significant early- onset AD risk factors and late-onset AD risk factors, like the apolipoprotein E4 (APOE4) gene, this study aims to evaluate the potential application of CRISPR/Cas9 as a possible treatment for AD.

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.

Increased Likelihood of Dementia with Coexisting Atrophy of Multiple Regions of Interest

BACKGROUND

Brain volume is associated with cognitive decline in later life, and cortical brain atrophy exceeding the normal range is related to inferior cognitive and behavioral outcomes in later life.

OBJECTIVE

To investigate the likelihood of cognitive decline, mild cognitive impairment (MCI), or dementia, when regional atrophy is present in participants' magnetic resonance imaging (MRI).

METHODS

Multi-center MRI data of 2,545 adults were utilized to measure regional volumes using NEUROPHET AQUA. Four lobes (frontal, parietal, temporal, and occipital), four Alzheimer's disease-related regions (entorhinal, fusiform, inferior temporal, and middle temporal area), and the hippocampus in the left and right hemispheres were measured and analyzed. The presence of regional atrophy from brain MRI was defined as ≤1.5 standard deviation (SD) compared to the age- and sex-matched cognitively normal population. The risk ratio for cognitive decline was investigated for participants with regional atrophy in contrast to those without regional atrophy.

RESULTS

The risk ratio for cognitive decline was significantly higher when hippocampal atrophy was present (MCI, 1.84, p < 0.001; dementia, 4.17, p < 0.001). Additionally, participants with joint atrophy in multiple regions showed a higher risk ratio for dementia, e.g., 9.6 risk ratio (95% confidence interval, 8.0-11.5), with atrophy identified in the frontal, temporal, and hippocampal gray matter, than those without atrophy.

CONCLUSIONS

Our study showed that individuals with multiple regional atrophy (either lobar or AD-specific regions) have a higher likelihood of developing dementia compared to the age- and sex-matched population without atrophy. Thus, further consideration is needed when assessing MRI findings.

Clusterization of Behavioral and Psychological Symptoms of Dementia as Assessed by Neuropsychiatric Inventory: A Case Against the Use of Principal Component Analysis

Background

The term Behavioral and Psychological Symptoms of Dementia (BPSD) covers a group of phenomenologically and medically distinct symptoms that rarely occur in isolation. Their therapy represents a major unmet medical need across dementias of different types, including Alzheimer's disease. Understanding of the symptom occurrence and their clusterization can inform clinical drug development and use of existing and future BPSD treatments.

Objective

The primary aim of the present study was to investigate the ability of a commonly used principal component analysis to identify BPSD patterns as assessed by Neuropsychiatric Inventory (NPI).

Methods

NPI scores from the Aging, Demographics, and Memory Study (ADAMS) were used to characterize reported occurrence of individual symptoms and their combinations. Based on this information, we have designed and conducted a simulation experiment to compare Principal Component analysis (PCA) and zero-inflated PCA (ZI PCA) by their ability to reveal true symptom associations.

Results

Exploratory analysis of the ADAMS database revealed overlapping multivariate distributions of NPI symptom scores. Simulation experiments have indicated that PCA and ZI PCA cannot handle data with multiple overlapping patterns. Although the principal component analysis approach is commonly applied to NPI scores, it is at risk to reveal BPSD clusters that are a statistical phenomenon rather than symptom associations occurring in clinical practice.

Conclusions

We recommend the thorough characterization of multivariate distributions before subjecting any dataset to Principal Component Analysis.

Serum neurofilament light chain and cognition decline in US elderly: A cross-sectional study

OBJECTIVE

Early identification of cognitive impairment in neurodegenerative diseases like Alzheimer's disease (AD) is crucial. Neurofilament, a potential biomarker for neurological disorders, has gained attention. Our study aims to investigate the relationship between serum neurofilament light (sNfL) levels and cognitive function in elderly individuals in the United States.

METHODS

This cross-sectional study analyzed data from participants aged 60 and above in the National Health and Nutrition Examination Survey (2013-2014). We collected sNfL levels, cognitive function tests, sociodemographic characteristics, comorbidities, and other variables. Weighted multiple linear regression models examined the relationship between ln(sNfL) and cognitive scores. Restricted cubic spline (RCS) visualization explored nonlinear relationships. The stratified analysis examined subgroups' ln(sNfL) and cognitive function association.

RESULTS

The study included 446 participants (47.73% male). Participants with ln(sNfL) levels between 2.58 and 2.81 pg/mL (second quintile) performed relatively well in cognitive tests. After adjusting for multiple factors, ln(sNfL) levels were negatively correlated with cognitive function, with adjusted β (95% CI) as follows: immediate recall test (IRT): -0.763 (-1.301 to -0.224), delayed recall test (DRT): -0.308 (-0.576 to -0.04), animal fluency test (AFT): -1.616 (-2.639 to -0.594), and digit symbol substitution test (DSST): -2.790 (-4.369 to -1.21). RCS curves showed nonlinear relationships between ln(sNfL) and DRT, AFT, with inflection points around 2.7 pg/mL. The stratified analysis revealed a negative correlation between ln(sNfL) and cognition in specific subgroups with distinct features, with an interaction between diabetes and ln(sNfL).

INTERPRETATION

Higher sNfL levels are associated with poorer cognitive function in the elderly population of the United States. sNfL shows promise as a potential biomarker for early identification of cognitive decline.

The Associations of Phosphorylated Tau 181 and Tau 231 Levels in Plasma and Cerebrospinal Fluid with Cognitive Function in Alzheimer's Disease: A Systematic Review and Meta-Analysis

Background

Cerebrospinal fluid (CSF) or blood biomarkers like phosphorylated tau proteins (p-tau) are used to detect Alzheimer's disease (AD) early. Increasing studies on cognitive function and blood or CSF p-tau levels are controversial.

Objective

Our study examined the potential of p-tau as a biomarker of cognitive status in normal control (NC), mild cognitive impairment (MCI), and AD patients.

Methods

We searched PubMed, Cochrane, Embase, and Web of Science for relevant material through 12 January 2023. 5,017 participants from 20 studies-1,033 AD, 2,077 MCI, and 1,907 NC-were evaluated. Quantitative analysis provided continuous outcomes as SMDs with 95% CIs. Begg tested publication bias.

Results

MCI patients had lower CSF p-tau181 levels than AD patients (SMD =-0.60, 95% CI (-0.85, -0.36)) but higher than healthy controls (SMD = 0.67). AD/MCI patients had greater plasma p-tau181 levels than healthy people (SMD =-0.73, 95% CI (-1.04, -0.43)). MCI patients had significantly lower p-tau231 levels than AD patients in plasma and CSF (SMD =-0.90, 95% CI (-0.82, -0.45)). MCI patients showed greater CSF and plasma p-tau231 than healthy controls (SMD = 1.34, 95% CI (0.89, 1.79) and 0.43, (0.23, 0.64)). Plasma p-tau181/231 levels also distinguished the three categories. MCI patients had higher levels than healthy people, while AD patients had higher levels than MCI patients.

Conclusions

CSF p-tau181 and p-tau231 biomarkers distinguished AD, MCI, and healthy populations. Plasma-based p-tau181 and p-tau231 biomarkers for AD and MCI need further study.

Hip Fractures in Patients with Dementia: An Emerging Orthopedic Concern

Hip fractures are a very common injury in the elderly population associated with an increased mortality rate. Currently, more and more elderly patients are diagnosed with dementia. Demented patients are more prone to falls and hip fractures compared to the general population because of conditions related to their disease such as instability, osteoporosis, poor muscle control and weakness. The coexistence of dementia and hip fractures is a difficult situation for both the patients and the treating physicians because of postoperative complications in this frail subgroup of patients and their inability to stand up and walk. To enhance the literature, we reviewed published studies of hip fracture patients suffering from dementia to discuss why they have more frequent hip fractures, to review their associated in-hospital complications, and to emphasize on their postoperative management to be able to reach the pre-injury activity level and optimal quality of life.

Metabolites and Cognitive Decline in a Puerto Rican Cohort

Background

Recent studies have identified plasma metabolites associated with cognitive decline and Alzheimer's disease; however, little research on this topic has been conducted in Latinos, especially Puerto Ricans.

Objective

This study aims to add to the growing body of metabolomics research in Latinos to better understand and improve the health of this population.

Methods

We assessed the association between plasma metabolites and global cognition over 12 years of follow-up in 736 participants of the Boston Puerto Rican Health Study (BPRHS). Metabolites were measured with untargeted metabolomic profiling (Metabolon, Inc) at baseline. We used covariable adjusted linear mixed models (LMM) with a metabolite * time interaction term to identify metabolites (of 621 measured) associated with ∼12 years cognitive trajectory.

Results

We observed strong inverse associations between medium-chain fatty acids, caproic acid, and the dicarboxylic acids, azelaic and sebacic acid, and global cognition. N-formylphenylalanine, a tyrosine pathway metabolite, was associated with improvement in cognitive trajectory.

Conclusions

The metabolites identified in this study are generally consistent with prior literature and highlight a role medium chain fatty acid and tyrosine metabolism in cognitive decline.

MIAMI-AD (Methylation in Aging and Methylation in AD): an integrative knowledgebase that facilitates explorations of DNA methylation across sex, aging, and Alzheimer's disease

Alzheimer's disease (AD) is a common neurodegenerative disorder with a significant impact on aging populations. DNA methylation (DNAm) alterations have been implicated in both the aging processes and the development of AD. Given that AD affects more women than men, it is also important to explore DNAm changes that occur specifically in each sex. We created MIAMI-AD, a comprehensive knowledge base containing manually curated summary statistics from 97 published tables in 37 studies, all of which included at least 100 participants. MIAMI-AD enables easy browsing, querying, and downloading DNAm associations at multiple levels - at individual CpG, gene, genomic regions, or genome-wide, in one or multiple studies. Moreover, it also offers tools to perform integrative analyses, such as comparing DNAm associations across different phenotypes or tissues, as well as interactive visualizations. Using several use case examples, we demonstrated that MIAMI-AD facilitates our understanding of age-associated CpGs in AD and the sex-specific roles of DNAm in AD. This open-access resource is freely available to the research community, and all the underlying data can be downloaded. MIAMI-AD (https://miami-ad.org/) facilitates integrative explorations to better understand the interplay between DNAm across aging, sex, and AD.

Design and feasibility of an Alzheimer's disease blood test study in a diverse community-based population

INTRODUCTION

Alzheimer's disease (AD) blood tests are likely to become increasingly important in clinical practice, but they need to be evaluated in diverse groups before use in the general population.

METHODS

This study enrolled a community-based sample of older adults in the St. Louis, Missouri, USA area. Participants completed a blood draw, Eight-Item Informant Interview to Differentiate Aging and Dementia (AD8® ), Montreal Cognitive Assessment (MoCA), and survey about their perceptions of the blood test. A subset of participants completed additional blood collection, amyloid positron emission tomography (PET), magnetic resonance imaging (MRI), and Clinical Dementia Rating (CDR® ).

RESULTS

Of the 859 participants enrolled in this ongoing study, 20.6% self-identified as Black or African American. The AD8 and MoCA correlated moderately with the CDR. The blood test was well accepted by the cohort, but it was perceived more positively by White and highly educated individuals.

DISCUSSION

Studying an AD blood test in a diverse population is feasible and may accelerate accurate diagnosis and implementation of effective treatments.

HIGHLIGHTS

A diverse group of older adults was recruited to evaluate a blood amyloid test. The enrollment rate was high and the blood test was well accepted by participants. Cognitive impairment screens have moderate performance in a diverse population. Alzheimer's disease blood tests are likely to be feasible for use in real-world settings.

Neuropsychological differential diagnosis of Alzheimer's disease and vascular dementia: a systematic review with meta-regressions

Introduction

Diagnostic classification systems and guidelines posit distinguishing patterns of impairment in Alzheimer's (AD) and vascular dementia (VaD). In our study, we aim to identify which diagnostic instruments distinguish them.

Methods

We searched PubMed and PsychInfo for empirical studies published until December 2020, which investigated differences in cognitive, behavioral, psychiatric, and functional measures in patients older than 64 years and reported information on VaD subtype, age, education, dementia severity, and proportion of women. We systematically reviewed these studies and conducted Bayesian hierarchical meta-regressions to quantify the evidence for differences using the Bayes factor (BF). The risk of bias was assessed using the Newcastle-Ottawa-Scale and funnel plots.

Results

We identified 122 studies with 17,850 AD and 5,247 VaD patients. Methodological limitations of the included studies are low comparability of patient groups and an untransparent patient selection process. In the digit span backward task, AD patients were nine times more probable (BF = 9.38) to outperform VaD patients (β g = 0.33, 95% ETI = 0.12, 0.52). In the phonemic fluency task, AD patients outperformed subcortical VaD (sVaD) patients (β g = 0.51, 95% ETI = 0.22, 0.77, BF = 42.36). VaD patients, in contrast, outperformed AD patients in verbal (β g = -0.61, 95% ETI = -0.97, -0.26, BF = 22.71) and visual (β g = -0.85, 95% ETI = -1.29, -0.32, BF = 13.67) delayed recall. We found the greatest difference in verbal memory, showing that sVaD patients outperform AD patients (β g = -0.64, 95% ETI = -0.88, -0.36, BF = 72.97). Finally, AD patients performed worse than sVaD patients in recognition memory tasks (β g = -0.76, 95% ETI = -1.26, -0.26, BF = 11.50).

Conclusion

Our findings show inferior performance of AD in episodic memory and superior performance in working memory. We found little support for other differences proposed by diagnostic systems and diagnostic guidelines. The utility of cognitive, behavioral, psychiatric, and functional measures in differential diagnosis is limited and should be complemented by other information. Finally, we identify research areas and avenues, which could significantly improve the diagnostic value of cognitive measures.

Local and Systemic Hypoxia as Inductors of Increased Aluminum and Iron Brain Accumulation Promoting the Onset of Alzheimer's Disease

Human environment is highly contaminated with aluminum, and aluminum is toxic to majority of tissues, particularly to neurons. In previous decades, aluminum exposure was frequently linked with the onset of Alzheimer's disease (AD), and increased levels of Al were detected in the brains of individuals with AD. People who live in a certain area are exposed to aluminum in a similar way (they eat the same vegetable and other foodstuffs, use similar cosmetics, and buy medications from the same manufacturer), nevertheless not all of them develop Alzheimer's disease. Majority of known risk factors for AD promote atherosclerosis and consequently reduce brain blood supply. In this review, we highlighted the significance of local (carotid disease and atherosclerosis of intracranial blood vessels) and systemic hypoxia (chronic obstructive pulmonary disease and anemia) in the development of AD. Nerve tissue is very sophisticated and sensitive to hypoxia and aluminum toxicity. As a side effect of compensatory mechanisms in case of hypoxia, neurons start to uptake aluminum and iron to a greater extent. This makes perfect a background for the gradual onset and development of AD.

The disproportionate burden of Alzheimer's disease and related dementias (ADRD) in diverse older adults diagnosed with cancer

INTRODUCTION

Older adults living with Alzheimer's disease and related dementias (ADRD) who are then diagnosed with cancer are an understudied population. While the role of cognitive impairment during and after cancer treatment have been well-studied, less is understood about patients who are living with ADRD and then develop cancer. The purpose of this study is to contribute evidence about our understanding of this vulnerable population.

MATERIALS AND METHODS

This was a retrospective cohort study of a linked, representative family of databases of cancer registries and Medicare administrative claims that make up the SEER-Medicare database. Older adults ages 68 and older with a first primary cancer type: breast, cervical, colorectal, lung, oral, or prostate were eligible for inclusion (N = 337,932). Prevalence estimates of ADRD across cancer types and a 5% non-cancer comparison sample were compared by patient factors.

RESULTS

The overall prevalence of patients who had an ADRD diagnosis anytime in the three years prior to their cancer diagnosis was 5.6%. Patients with ADRD were more likely to be female, older (over age 75), a racial/ethnic minority, single, with multiple chronic conditions, and a tumor diagnosed early (stage I) or were unstaged. Black patients with colorectal and oral cancer had the highest and second highest prevalence of ADRD compared to White patients (13.46% vs 7.95% and 12.64% vs 7.82% respectively, p < .0001). We observed the highest prevalence of ADRD among Black patients for breast (11.85%), cervical (11.98%), lung (8.41%), prostate (4.83), and the 5% sample (9.50%, p > .0001).

DISCUSSION

The higher prevalence of ADRD among Black and Latine older adults with cancer not only aligns with the trend observed in our non-cancer comparison sample, but also, these findings demonstrate the compounded risk experienced by minoritized older adults over the life course. The greater than expected prevalence of patients with ADRD who go on to develop cancer demonstrates better assessment of cognition is urgently needed. Accurate identification of these vulnerable populations is critical to improve assessment, care coordination, and address inequities in screening and treatment planning.

Association between napping and cognitive impairment: A systematic review and meta-analysis

STUDY OBJECTIVES

Increasing evidence suggests that napping is associated with cognitive impairment and dementia, but the conclusions are inconsistent. Moreover, the extent of the risk is uncertain. We therefore conducted a systematic review and meta-analysis to quantify the connection between napping and cognitive impairment.

METHODS

We performed a systematic search of PubMed, EMBASE, Web of Science, and Cochrane Library for studies that were published up to June 2023, and assessed associations between napping and cognitive impairment. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated as the effect sizes for all studies. Heterogeneity and potential publication biases were assessed.

RESULTS

A total of 4535 papers were retrieved, with 20 reports assessing the relationships between napping and cognitive impairment. Pooled analysis indicated that napping was associated with dementia (OR = 1.14; 95% CI: 1.07-1.21). Importantly, we found that those napping longer than 30, 45, and 60 min/day were 35%, 41%, and 40%, respectively, more likely to have an increased risk of cognitive impairment (30 min: OR = 1.35; 95% CI: 1.24-1.48; 45 min: OR = 1.41; 95% CI: 1.27-1.58; 60 min: OR = 1.40; 95% CI: 1.26-1.56). North America and Europe showed that associations existed between napping and cognitive impairment (North America: OR = 1.15; 95% CI: 1.04-1.27; Europe: OR = 1.13; 95% CI: 1.08-1.18).

CONCLUSIONS

This meta-analysis indicated associations between long napping durations and cognitive impairment or dementia, suggesting that longer napping might be a potential risk factor of adverse cognitive outcomes.

Extracellular matrix proteoglycans support aged hippocampus networks: a potential cellular-level mechanism of brain reserve

One hallmark of normative brain aging is vast heterogeneity in whether older people succumb to or resist cognitive decline. Resilience describes a brain's capacity to maintain cognition in the face of aging and disease. One factor influencing resilience is brain reserve-the status of neurobiological resources available to support neuronal circuits as dysfunction accumulates. This study uses a cohort of behaviorally characterized adult, middle-aged, and aged rats to test whether neurobiological factors that protect inhibitory neurotransmission and synapse function represent key components of brain reserve. Histochemical analysis of extracellular matrix proteoglycans, which play critical roles in stabilizing synapses and modulating inhibitory neuron excitability, was conducted alongside analyses of lipofuscin-associated autofluorescence. The findings indicate that aging results in lower proteoglycan density and more lipofuscin in CA3. Aged rats with higher proteoglycan density exhibited better performance on the Morris watermaze, whereas lipofuscin abundance was not related to spatial memory. These data suggest that the local environment around neurons may protect against synapse dysfunction or hyperexcitability and could contribute to brain reserve mechanisms.