Trends in the Risk of Cognitive Impairment in the United States, 1996-2014

Religious Involvement and Cognitive Function Among White, Black, and Hispanic Older Adults

We examined whether religious involvement was associated with cognitive function among older adults in the 2006-2020 waves of the Health and Retirement Study. Using growth curve analysis, we found the association between religious involvement and cognition varied by facet of religious involvement and race and Hispanic ethnicity. Attending religious services with friends was associated with higher initial levels of cognitive function (b = 0.22, p < .05). For Hispanic older adults, frequent attendance at religious services was associated with a slower rate of cognitive decline (b = 0.16, p < .01). Stratified models by race and Hispanic ethnicity demonstrated that religious salience was associated with lower initial levels of cognitive function among non-Hispanic White adults (b = -0.19, p < .01). We found no association between religious involvement and cognitive function among non-Hispanic Black respondents. In sum, elements of religious involvement are positively or negatively related to cognitive function in later life and vary by race and ethnicity.

The influencing factors of cognitive impairment in elderly individuals in Chengdu city: a cross-sectional study based on AD8

BACKGROUND

With the aging of society, cognitive impairment in elderly people is becoming increasingly common and has caused major public health problems. The screening of cognitive impairment in elderly people and its related influencing factors can aid in the development of relevant intervention and improvement strategies.

METHODS

In this study, stratified random cluster sampling was used to conduct a cross-sectional survey of elderly individuals aged 65 years in Chengdu, Sichuan Province, through an electronic questionnaire from November 2022 to November 2023. Descriptive analysis and logistic regression analysis were used to investigate cognitive impairment and its relevant influencing factors.

RESULTS

Among the 16,609 elderly people, 7524 (45.3%) were males and 9085 (54.7%) were females, with an average age of 73.6 ± 6.5 years (age range 65-101 years). The average years of education was 5.9 ± 6.2 years, and the proportion of individuals with cognitive impairment was 13.1%. With increasing age, the risk of cognitive impairment increased significantly. The risk factors for cognitive impairment in elderly individuals included advanced age, hypertension, heart disease, diabetes, cerebrovascular disease, depressive symptoms, and anxiety symptoms, while the protective factors included higher education level, married status, and greater life satisfaction.

CONCLUSION

Cognitive impairment in elderly individuals in Chengdu is serious. We can intervene in and improve cognitive impairment in elderly people by controlling blood pressure and blood sugar, treating depressive and anxiety symptoms and developing community colleges for elderly people and increasing satisfaction with life.

Associations of Muscle-Strengthening Activity and Cognitive Function in Community-Dwelling Middle-Aged and Older Adults

OBJECTIVE

To determine the associations between muscle-strengthening activity (MSA) and cognitive function among middle-aged and older adults.

METHODS

This cross-sectional study included 2973 participants aged ≥55 in the Cooper Center Longitudinal Study. Participants self-reported leisure-time physical activity. Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA). The associations of reported MSA frequency (0-1 vs. ≥2 sessions/week) and volume (zero, low: ≤250, medium: 250-420, high: >420 MET minutes/week) with mild cognitive impairment (MCI, defined as MoCA<26) and MoCA total score were examined using logistic and linear regression.

RESULTS

Individuals who participated in ≥2 MSA sessions/week had a significantly higher MoCA total score. Participants with medium MSA volume were significantly associated with lower odds of being classified as MCI and associated with a higher MoCA total score than those with zero volume.

CONCLUSIONS

Engaging in MSA is associated with cognitive health among middle-aged and older adults independent of aerobic exercise.

Trends in Memory Function and Memory Impairment Among Older Adults in the United States and Europe, 1996-2018

BACKGROUND

Single-country studies document varying time trends in memory function and impairment. Comparative analyses are limited.

METHODS

We used self-respondent data on adults aged 50+ years in 13 countries from 3 surveys (United States: Health and Retirement Study, 1998-2018; England: English Longitudinal Study of Ageing, 2002-2018; 11 European countries: Survey of Health, Ageing and Retirement in Europe, 2004-2019). Memory is measured with tests of immediate and delayed word recall. Unweighted age- and gender-adjusted mixed effects regression models as well as models with adjustments for additional sociodemographic characteristics and health behaviors were examined. Heterogeneity in trends by gender, age group, and educational attainment was measured.

RESULTS

The age-adjusted 10-year improvement in average test score is 0.04 standard deviations (SDs) (95% confidence interval [CI]: 0.03, 0.05) in the United States, 0.17 SDs (95% CI: 0.15, 0.19) in England, and 0.24 SDs (95% CI: 0.23, 0.25) in SHARE countries. Trends are largely similar across gender, age groups, and educational attainment. Regional differences in trends remain after adjustment for potential mechanisms. The difference between the United States and other countries is particularly large under 75 years of age compared to 75 years and older.

CONCLUSIONS

Pace of improvement in memory function varies strongly across countries. On average, the 11 European countries studied had the fastest improvement, followed by England. The trend in the United States indicates improvement, but at a much slower pace compared to that in England and other European countries. Uncovering the causes for the cross-country heterogeneity in time trends, and in particular the reasons for the comparatively poor performance of the United States, should be both a research and public health priority.

Racial Differences in the Association Between Loneliness and Cognitive Impairment Among Older Black and White Men

BACKGROUND

Loneliness is a biopsychosocial stressor linked to poor health outcomes including dementia. Few studies have focused on this association among men and even fewer have examined racial disparities in loneliness and cognitive functioning among this group. The purpose of this study was to examine racial differences in the association between loneliness and cognitive functioning among men in the 2016 wave of the Health and Retirement Study.

METHODS

This cross-sectional study included Black and White men who completed the core questionnaire and the Leave Behind Questionnaire (n = 2 227). Any cognitive impairment was the primary outcome and was measured by a dichotomous variable derived from a modified version of the Telephone Interview for Cognitive Status. Loneliness was the primary independent variable and was derived from the 3-item University of California, Los Angeles (UCLA) Loneliness Scale. Modified Poisson regression models with robust standard errors were estimated to generate prevalence ratios (PRs) and corresponding 95% confidence intervals (CIs).

RESULTS

Black men comprised 18.4% of the study sample; however, the proportion of this group with scores indicating cognitive impairment (35.9%) doubled the corresponding percentage of white men (17.6%). Findings from race-stratified modified Poisson regression models indicated that loneliness was associated with a higher prevalence of any cognitive impairment for White men (PR = 1.24, CI: 1.05-1.47), but not for Black men (PR = 0.92, CI: 0.73-1.16).

CONCLUSIONS

Our results underscore the complexity of race when investigating the association between loneliness and cognitive impairment among older men. Additional studies are needed to further examine how loneliness may have racially distinct implications for cognitive outcomes among the population.

Dementia Care Among United States Dialysis Providers: A Mixed Methods Study Evaluating Clinician Comfort and Knowledge

Rationale & Objective

Given the high burden of dementia in dialysis patients, the dialysis workforce needs to be prepared to provide high-quality, person-centered dementia care. We explored comfort with and knowledge of dementia among US dialysis care providers.

Study Design

Web-based survey.

Setting & Participants

Emails were sent to National Kidney Foundation and National Association of Nephrology Technicians/Technologists membership listservs (September 26, 2022-October 22, 2022). In total, 1,121 respondents had complete data for analysis (57%, 35-49 years; 62% female; 62%/22% White/African American) including 81 physicians, 61 advanced practice providers, 230 nurse managers, 260 nurses, 202 social workers, 195 dietitians, and 86 dialysis patient care technicians.

Exposures

Provider role, age, tenure, self-reported gender, previous dementia training, and awareness of dementia guidance.

Outcomes

Dementia Knowledge (assessed using Dementia Knowledge Assessment Scale [DKAS; score range, 0-25]).

Analytic Approach

Characteristics of respondents, comfort with dementia care, and dementia knowledge were summarized and tabulated overall and by role. Robust regression was used to obtain coefficients confidence intervals for the associations between characteristics and DKAS scores, adjusting for role and tenure. Free-text responses to an open-ended question about treating patients with dementia or cognitive impairment were analyzed using thematic analysis.

Results

Dementia knowledge among US dialysis providers may be limited (overall DKAS score = 17; range, 13-21 across roles), despite most reporting knowing when patients had dementia (97%) and receiving training in dementia care (62%). Further, training may be inadequate: those who reported receiving dementia training had lower DKAS scores than those who reported not receiving training (β, -3.9; 95% CI, -4.4 to -3.4). Thematic analysis of open-ended responses suggested that the impact of dementia on dialysis care and management and treatment beyond dialysis care are challenging for providers.

Limitations

Data were self-reported and limited information was gathered about quality, content, and timing of dementia training received.

Conclusion

Many US dialysis care providers had suboptimal dementia knowledge, despite reporting being comfortable with providing dementia care and reporting they received prior training. Qualitative findings indicate complexity among providers regarding comfort with and knowledge of treating patients with cognitive impairment. Targeted training for the dialysis workforce in dementia knowledge and best practices for person-centered dementia care is warranted.

Application of a new definition of sarcopenic obesity in middle-aged and older adults and association with cognitive function: Findings from the National Health and Nutrition Examination Survey 1999-2002

BACKGROUND & AIMS

The role of sarcopenic obesity (SO) in impaired cognitive function has been investigated in several observational studies, but results have been mixed. This study applied the proposed European Society for Clinical Nutrition and Metabolism (ESPEN)-European Association for the Study of Obesity (EASO) definition of SO to a representative population aged ≥50 years to identify the association between SO and cognitive function.

METHODS

Data from the National Health and Nutrition Examination Survey 1999-2002 waves were used. At the screening phase, body mass index or waist circumference were used to evaluate obesity; sarcopenia was identified using the SARC-F questionnaire. At the diagnostic phase I and II, sarcopenia was assessed using knee extensor isometric strength and appendicular lean mass, and fat mass percent was used to assess obesity. Cognitive function in older participants (60-85 years) was assessed using the Digit Symbol Substitution Test. A self-reported memory question was used in middle-aged individuals (50-59 years).

RESULTS

The sample included 2356 participants (men, 44.7%). The prevalence of SO was 32.3%, 21.2% and 15.0% at the screening, diagnosis I, and diagnosis II, respectively. Significant associations between SO and cognitive impairment were observed in individuals aged 60-85 at diagnosis I (OR: 2.3, 95%CI 1.4-3.8, P = 0.007) and diagnosis II (OR: 2.7, 95%CI 1.5-4.9, P = 0.004).

CONCLUSION

The new ESPEN-EASO definition of SO identified a high prevalence of SO cases. A significant association between SO and poor cognitive function in older individuals was observed.

tDCS-enhanced cognitive training improves attention and alters connectivity in control and somatomotor networks: A triple blind study

BACKGROUND

Executive dysfunction such as inattention or forgetfulness can lead to disruptions in a person's daily functioning and quality of life.

OBJECTIVE/HYPOTHESIS

This triple-blinded randomized clinical trial assessed the efficacy of bifrontal (over the forehead) transcranial direct current stimulation (tDCS) concurrent with cognitive training to improve cognitive performance in a healthy sample.

METHODS

Fifty-eight participants were randomly assigned to one of three stimulation conditions (2 mA left anode-right cathode, 2 mA right anode-left cathode, or sham), which was administered with cognitive training tasks 3x/week over 12 weeks with assessments at baseline, midpoint (6 weeks), and post-training (12 weeks). We assessed cognitive performance, functional connectivity, and the influence of individual differences in training advancement.

RESULTS

Forty participants completed training. We found that at midpoint and post, all groups improved significantly on overall cognitive performance. The left anode group's attention & vigilance score improved significantly at post, but the other two groups did not. Greater attention training advancement predicted attention improvement by post, most notably in the left anode group. Finally, within-network connectivity decreased in the control network and increased in the somatomotor network across all groups.

CONCLUSIONS

These results suggest that, given cognitive training, the left anode montage is more effective at improving attention than the right anode montage and sham. Future research may focus on the application of the left anode montage during cognitive training to assess its effectiveness in improving cognition in neuropsychiatric disorders.

Changes in prevalence and incidence of dementia and risk factors for dementia: an analysis from cohort studies

BACKGROUND

Some cohort studies have reported a decline in dementia prevalence and incidence over time, although these findings have not been consistent across studies. We reviewed evidence on changes in dementia prevalence and incidence over time using published population-based cohort studies that had used consistent methods with each wave and aimed to quantify associated changes in risk factors over time using population attributable fractions (PAFs).

METHODS

We searched for systematic reviews of cohort studies examining changes in dementia prevalence or incidence over time. We searched PubMed for publications from database inception up to Jan 12, 2023, using the search terms "systematic review" AND "dementia" AND ("prevalence" OR "incidence"), with no language restrictions. We repeated this search on March 28, 2024. From eligible systematic reviews, we searched the references and selected peer-reviewed publications about cohort studies where dementia prevalence or incidence was measured in the same geographical location, at a minimum of two timepoints, and that reported age-standardised prevalence or incidence of dementia. Additionally, data had to be from population-based samples, in which participants' cognitive status was assessed and where validated criteria were used to diagnose dementia. We extracted summary-level data from each paper about dementia risk factors, contacting authors when such data were not available in the published paper, and calculated PAFs for each risk factor at all available timepoints. Where possible, we linked changes in dementia prevalence or incidence with changes in the prevalence of risk factors.

FINDINGS

We identified 1925 records in our initial search, of which five eligible systematic reviews were identified. Within these systematic reviews, we identified 71 potentially eligible primary papers, of which 27 were included in our analysis. 13 (48%) of 27 primary papers reported change in prevalence of dementia, ten (37%) reported change in incidence of dementia, and four (15%) reported change in both incidence and prevalence of dementia. Studies reporting change in dementia incidence over time in Europe (n=5) and the USA (n=5) consistently reported a declining incidence in dementia. One study from Japan reported an increase in dementia prevalence and incidence and a stable incidence was reported in one study from Nigeria. Overall, across studies, the PAFs for less education or smoking, or both, generally declined over time, whereas PAFs for obesity, hypertension, and diabetes generally increased. The decrease in PAFs for less education and smoking was associated with a decline in the incidence of dementia in the Framingham study (Framingham, MA, USA, 1997-2013), the only study with sufficient data to allow analysis.

INTERPRETATION

Our findings suggest that lifestyle interventions such as compulsory education and reducing rates of smoking through country-level policy changes could be associated with an observed reduction, and therefore future reduction, in the incidence of dementia. More studies are needed in low-income and middle-income countries, where the burden of dementia is highest, and continues to increase.

FUNDING

National Institute for Health and Care Research Three Schools' Dementia Research Programme.

Stress and Loneliness Among Family Caregivers of Older Persons With Cognitive Impairment: The Mediating Role of Social Isolation and the Moderating Role of Personal Mastery

OBJECTIVES

Relatively little attention has been paid to the underlying processes and conditions leading to loneliness among caregivers of older persons with cognitive impairment (PCI). Drawing upon the caregiver stress-process model and the social relationship expectations framework, this study examined the mediating role of social isolation and the moderating role of caregiver personal mastery in the association between PCI memory and behavioral problems and caregiver loneliness.

METHODS

Structural equation modeling was applied to cross-sectional data from 266 caregivers in Singapore.

RESULTS

Caregiver-reported PCI memory and behavioral problems were associated with increased levels of caregiver loneliness. Caregiver social isolation partially mediated the association and caregiver personal mastery moderated the association.

DISCUSSION

Caregivers with low mastery were more likely to experience loneliness due in part to social isolation resulting from their PCI's memory and behavioral problems. Tailored interventions should address caregiver social isolation and foster caregiver personal mastery.

Associations between circadian alignment and cognitive functioning in a nationally representative sample of older adults

Proper alignment of activity-rest and light-dark patterns allows for healthy bodily functions to occur at optimal times of the day. Disruptions to this alignment may cause poor sleep as well as physical, mental, and cognitive problems. The purpose of this cross-sectional study was to determine if poorer circadian alignment was associated with decreased cognitive functioning among older (> 60 years) participants in the National Health and Nutrition Examination Survey. We utilized actigraphy-based rest-activity and dark-light measurements to calculate phasor magnitude (strength of circadian alignment coupling) and phasor angle (phase difference between activity-rest and light-dark cycles). Multiple linear regression models were used to determine associations of phasor magnitude and angle with performance in various cognitive tests, including Digit Symbol Substitution Test score (DSSS), CERAD Savings Percentage (CSP), and Animal Fluency Test (AFT) score. The results showed that a lower phasor magnitude (which indicates decreased strength of alignment coupling between rest-activity and dark-light cycles) was significantly associated with decreased DSSS (indicating slower processing speed and poorer working memory) when controlling for many important sociodemographic factors. However, this association became non-significant when accounting for sleep duration and total physical activity. Phasor angle did not have a significant association with any of the cognitive scores. Overall, we provided evidence indicating that circadian alignment may be a predictor of cognitive performance. Future studies should investigate whether improving circadian alignment may improve cognitive function and prevent cognitive decline.

Dyadic contagion in cognitive function: A nationally-representative longitudinal study of older U.S. couples

Later-life cognitive function is strongly influenced by one's environment. At this life stage, a partner's behaviors and attributes-including their own cognitive status-are a key environmental determinant. A recent "social allostasis" theory also yields specific predictions on patterns of mutual influence-or "contagion"-in cognitive function. Yet, no population representative studies have examined these coupled dynamics. Using recently developed fixed-effects cross-lagged panel modeling (FE-CLPM) methods and ten-year data from the Health and Retirement Study-nationally-representative of U.S. adults over 50-the current study filled this gap. Results supported dyadic cognitive contagion over the long- but not short-run. Short-term associations suggested intriguing "cognitive cycling" possibilities among both men and women that need further investigation. Overall, results supported a theoretical model of coupled "cognitive careers," and relational inducement of allostatic load. Especially among men, recurrent impulses also cumulatively induced substantial path-dependent cognitive improvements, supporting the added value of repeated over one-time interventions. Theoretical and substantive implications are discussed.

Seroprevalence of West Nile Virus in Tampa Bay Florida Patients Admitted to Hospital during 2020-2021 for Respiratory Symptoms

West Nile virus (WNV) is an arbovirus spread primarily by Culex mosquitoes, with humans being a dead-end host. WNV was introduced to Florida in 2001, with 467 confirmed cases since. It is estimated that 80 percent of cases are asymptomatic, with mild cases presenting as a non-specific flu-like illness. Currently, detection of WNV in humans occurs primarily in healthcare settings via RT-PCR or CSF IgM when patients present with severe manifestations of disease including fever, meningitis, encephalitis, or acute flaccid paralysis. Given the short window of detectable viremia and requirement for CSF sampling, most WNV infections never receive an official diagnosis. This study utilized enzyme-linked immunosorbent assay (ELISA) to detect WNV IgG antibodies in 250 patient serum and plasma samples collected at Tampa General Hospital during 2020 and 2021. Plaque reduction neutralization tests were used to confirm ELISA results. Out of the 250 patients included in this study, 18.8% of them were IgG positive, consistent with previous WNV exposure. There was no relationship between WNV exposure and age or sex.

Linking Adverse Childhood Experiences and Other Risk Factors to Subjective Cognitive Decline in an Aging Population

Introduction

The Centers for Disease Control and Prevention's Healthy Brain Initiative (HBI) encourages an interdisciplinary approach to addressing the burden of subjective cognitive decline (SCD) among the aging US population as that population continues to increase. Our study is one of the first to evaluate associations between SCD and adverse childhood experiences (ACEs) and other modifiable risk factors to support implementation of the initiative.

Methods

We used multivariate logistic regression to assess data from the 2020 Behavioral Risk Factor Surveillance System survey to evaluate associations between SCD and ACEs scores and sociodemographic, behavioral, and clinical risk factors. Models were weighted to account for the complex survey design.

Results

Approximately 8.1% of survey respondents reported experiencing SCD within the past 12 months. Adjusted regression analysis showed that conditions such as depression (AOR, 2.85; 95% CI, 2.29-3.55), arthritis (AOR, 1.30; 95% CI, 1.05-1.60), and diabetes (AOR, 1.33; 95% CI, 1.05-1.68) were significantly associated with SCD. SCD was also associated with experiencing more than 3 falls per year (AOR, 2.95; 95% CI, 2.13-4.09), sleeping more than 9 hours per night (AOR, 2.06; 95% CI, 1.37-3.09), and physical inactivity (AOR, 1.32; 95% CI, 1.03-1.68). Two or more ACEs also significantly increased the odds of SCD (AOR, 1.69; 95% CI, 1.36-2.10).

Conclusion

Findings from our study can be used to inform policy, environment, and systems change efforts aimed at addressing modifiable risk factors to support healthy aging. The role of ACEs as determinants of brain health across the life course should also be considered in the design of clinical and community-based interventions.

"We adjusted for race": now what? A systematic review of utilization and reporting of race in American Journal of Epidemiology and Epidemiology, 2020-2021

Race is a social construct, commonly used in epidemiologic research to adjust for confounding. However, adjustment of race may mask racial disparities, thereby perpetuating structural racism. We conducted a systematic review of articles published in Epidemiology and American Journal of Epidemiology between 2020 and 2021 to (1) understand how race, ethnicity, and similar social constructs were operationalized, used, and reported; and (2) characterize good and poor practices of utilization and reporting of race data on the basis of the extent to which they reveal or mask systemic racism. Original research articles were considered for full review and data extraction if race data were used in the study analysis. We extracted how race was categorized, used-as a descriptor, confounder, or for effect measure modification (EMM)-and reported if the authors discussed racial disparities and systemic bias-related mechanisms responsible for perpetuating the disparities. Of the 561 articles, 299 had race data available and 192 (34.2%) used race data in analyses. Among the 160 US-based studies, 81 different racial categorizations were used. Race was most often used as a confounder (52%), followed by effect measure modifier (33%), and descriptive variable (12%). Fewer than 1 in 4 articles (22.9%) exhibited good practices (EMM along with discussing disparities and mechanisms), 63.5% of the articles exhibited poor practices (confounding only or not discussing mechanisms), and 13.5% were considered neither poor nor good practices. We discuss implications and provide 13 recommendations for operationalization, utilization, and reporting of race in epidemiologic and public health research.

The association of upper airway anatomy with cognitive test performance: the Multi-Ethnic Study of Atherosclerosis

BACKGROUND

Numerous upper airway anatomy characteristics are risk factors for sleep apnea, which affects 26% of older Americans, and more severe sleep apnea is associated with cognitive impairment. This study explores the pathophysiology and links between upper airway anatomy, sleep, and cognition.

METHODS

Participants in the Multi-Ethnic Study of Atherosclerosis underwent an upper airway MRI, polysomnography to assess sleep measures including the apnea-hypopnea index (AHI) and completed the Cognitive Abilities Screening Instrument (CASI). Two model selection techniques selected from among 67 upper airway measures those that are most strongly associated with CASI score. The associations of selected upper airway measures with AHI, AHI with CASI score, and selected upper airway anatomy measures with CASI score, both alone and after adjustment for AHI, were assessed using linear regression.

RESULTS

Soft palate volume, maxillary divergence, and upper facial height were significantly positively associated with higher CASI score, indicating better cognition. The coefficients were small, with a 1 standard deviation (SD) increase in these variables being associated with a 0.83, 0.75, and 0.70 point higher CASI score, respectively. Additional adjustment for AHI very slightly attenuated these associations. Larger soft palate volume was significantly associated with higher AHI (15% higher AHI (95% CI 2%,28%) per SD). Higher AHI was marginally associated with higher CASI score (0.43 (95% CI 0.01,0.85) per AHI doubling).

CONCLUSIONS

Three upper airway measures were weakly but significantly associated with higher global cognitive test performance. Sleep apnea did not appear to be the mechanism through which these upper airway and cognition associations were acting. Further research on the selected upper airway measures is recommended.

Racial, Ethnic, Nativity, and Educational Disparities in Cognitive Impairment and Activity Limitations in the United States, 1998-2016

Despite extensive research on cognitive impairment and limitations in basic activities of daily living, no study has investigated the burden of their co-occurrence (co-impairment). Using the Health and Retirement Study data and incidence-based multistate models, we study the population burden of co-impairment using three key indicators: mean age at onset, lifetime risk, and health expectancy. We examine patterns by gender, race, ethnicity, nativity, education, and their interactions for U.S. residents aged 50-100. Furthermore, we analyze what fractions of racial, ethnic, and nativity disparities in co-impairment are attributable to inequalities in educational attainment. Results reveal that an estimated 56% of women and 41% of men aged 50 will experience co-impairment in their remaining life expectancy. Men experience an earlier onset of co-impairment than women (74 vs. 77 years), and women live longer in co-impairment than men (3.4 vs. 1.9 years). Individuals who are Black, Latinx, and lower educated, especially those experiencing intersecting disadvantages, have substantially higher lifetime risk of co-impairment, earlier co-impairment onset, and longer life in co-impairment than their counterparts. Up to 75% of racial, ethnic, and nativity disparity is attributable to inequality in educational attainment. This study provides novel insights into the burden of co-impairment and offers evidence of dramatic disparities in the older U.S. population.

Pragmatic approaches to handling practice effects in longitudinal cognitive aging research

INTRODUCTION

The challenge of accounting for practice effects (PEs) when modeling cognitive change was amplified by the COVID-19 pandemic, which introduced period and mode effects that may bias the estimation of cognitive trajectory.

METHODS

In three Kaiser Permanente Northern California prospective cohorts, we compared predicted cognitive trajectories and the association of grip strength with cognitive decline using three approaches: (1) no acknowledgment of PE, (2) inclusion of a wave indicator, and (3) constraining PE based on a preliminary model (APM) fit using a subset of the data.

RESULTS

APM-based correction for PEs based on balanced, pre-pandemic data, and with current age as the timescale produced the smallest discrepancy between within-person and between-person estimated age effects. Estimated associations between grip strength and cognitive decline were not sensitive to the approach used.

DISCUSSION

Constraining PEs based on a preliminary model is a flexible, pragmatic approach allowing for meaningful interpretation of cognitive change.

HIGHLIGHTS

The magnitude of practice effects (PEs) varied widely by study. When PEs were present, the three PE approaches resulted in divergent estimated age-related cognitive trajectories. Estimated age-related cognitive trajectories were sometimes implausible in models that did not account for PEs. The associations between grip strength and cognitive decline did not differ by the PE approach used. Constraining PEs based on estimates from a preliminary model allows for a meaningful interpretation of cognitive change.

Participatory and Receptive Arts Engagement in Older Adults: Associations with Cognition Over a Seven-Year Period

There is growing evidence for the impact of arts engagement on later life cognition. However, confounding by socioeconomic factors may have led to an overestimation of this association. We analyzed data from 4,344 older adults in the Wisconsin Longitudinal Study. We measured participatory (e.g. painting, making music, crafts) and receptive (e.g. concert, play, museum) arts engagement separately. Participants completed six neurocognitive tests measuring two distinct domains of cognitive function (episodic/working memory and executive function/language) concurrently and seven years later. We used inverse probability of treatment weighting (IPTW) to remove confounding by a range of demographic and socioeconomic factors. Engaging in participatory or receptive arts for up to one hour per week (but not more frequently) was associated with better subsequent executive function/language. Similarly, engaging in receptive arts activities for up to three hours per week (but not more frequently) was associated with better subsequent episodic/working memory. These effects were of similar sizes to doing vigorous physical activity for up to one hour per week. However, our findings also highlight key methodological issues when exploring the relationship between arts engagement and cognition that should be considered in future studies, including measurement bias, life-course stage, length of follow-up, variation in outcomes, attrition, and missing data.

The Role of Body Mass Index, Advanced Age, and Low Educational Attainment in Mild Cognitive Impairment among the Older Adult Population: A Study in a Rural Area in Indonesia

This study evaluated the prevalence of mild cognitive impairment (MCI) and factors associated with MCI among older adults in a rural area of Indonesia. This cross-sectional study was conducted in a rural area of East Java, Indonesia. Four hundred and twenty-seven older adults aged ≥60 years were included in the study. MCI was assessed using the Brain Health Test Cognitive Tool. Data related to possible risk factors were obtained using semi-structured questionnaires. The indirect body mass index was determined based on ulnar length. The prevalence of MCI was 12.9%. Being underweight (<18.5 kg/m2) (odds ratio [OR], 2.42; 95% confidence interval [CI], 1.17-4.97; p = 0.016), requiring assistance to manage money or medications (OR, 2.72; 95% CI, 1.02-7.23; p = 0.045), age ≥70 years (OR, 2.50; 95% CI, 1.11-5.60; p = 0.026), and having an educational attainment of ≤6 years (OR, 4.92; 95% CI, 1.92-12.60; p = 0.001) were significantly associated with MCI. In this Indonesian older adult population, underweight people who had an educational attainment of <6 years, those aged ≥70 years, and those who needed assistance to manage money or medications were more likely to have MCI.

Threshold effects of the relationship between physical exercise and cognitive function in the short-sleep elder population

Background

It has been demonstrated that elderly people's cognitive capacities can be improved with exercise, and short sleep is linked to cognitive decline. However, the impact of physical exercise on cognitive performance in seniors who do not get enough sleep is largely unknown. This makes it an intriguing subject to explore further.

Methods

This study consisted of elders (over 60 years old) who participated throughout the National Health and Nutrition Examination Survey's 2011-2014 cycle (NHANES). Weighted linear regression model and restricted cubic splines analysis were performed to evaluate the association between physical exercise and cognitive function. In the end, 1,615 samples were scrutinized and the total number of weighted respondents was 28,607,569.

Results

Results showed that in the Animal Fluency test and the Digit Symbol Substitution test, a positive association was found between physical exercise volume and scores in the fully adjusted model. A two-piecewise linear regression model was then applied to explore the threshold effect of exercise on cognitive performance. Before 960 and 800 MET-minutes/week, there were consistent positive relationship between exercise and scores of the Animal Fluency test [ß (95% CI): 0.233 (0.154, 0.312), p < 0.001] and Digit Symbol Substitution test [β (95% CI): 0.555 (0.332, 0.778), p < 0.001], respectively. However, there was a saturation effect where physical exercise volume reached the two inflection points.

Conclusion

According to our research, the benefit of exercise did not always expand with the exercise volume increment under the short-sleep condition, which challenged existing knowledge. The short-sleep elder group could maintain cognitive performance with no more than 800 MET-minutes/week of physical exercise. Verification of these findings requires further biological investigations.

Longitudinal trajectories of dietary quality and cognitive performance in older adults: Results from a 6-year cohort study

BACKGROUND

Diet affects cognitive performance, but most previous studies only assessed diet once. Trajectory analysis of diet measured at multiple timepoints can identify subpopulations requiring more interventional efforts. We thus assessed associations between dietary trajectories and cognitive performance in older adults.

METHODS

This was a 6-year prospective cohort study involving 356 ethnically Chinese, non-demented, community-dwelling older adults recruited between 2011 and 2013. At baseline and at 4th- and 6th-year follow-ups, dietary intakes of the participants were assessed using food frequency questionnaires. Dietary quality was graded using the modified Alternative Healthy Eating Index (mAHEI) with seven components; longitudinal trajectories of dietary quality were derived using latent growth mixture modelling. Outcomes were global- and domain-specific cognitive performance (attention, memory, executive functions, and verbal fluency). Multivariable regressions adjusting for important covariates (sex, age, energy intake, APOE risk alleles, depressive symptoms, and body mass index (BMI)) assessed associations between the dietary trajectories and cognitive outcomes.

RESULTS

Included participants had a mean age of 71.6 years and a mean BMI of 23.8 kg/m2. Three mutually exclusive dietary quality trajectories, namely "deteriorating", "improving", and "stable-high", were derived. Compared with the stable-high trajectory, the improving trajectory was associated with a lower z-score for the memory domain (β: -0.403; 95% CI: -0.656, -0.151; P = 0.002), which was consistently observed for the four individual tests of the domain (β range: -0.324 to -0.448; all P < 0.05). In unadjusted analysis, the deteriorating trajectory was associated with a 0.369 lower z-score for the verbal fluency domain (95% CI: -0.700, -0.039 P = 0.028), though attenuated to borderline significance with adjustment for covariates. Sex and BMI modified some of these associations. No other associations were observed for global cognition or other cognitive domains.

CONCLUSIONS

In Taiwanese older adults, consistently high dietary quality is associated with better cognitive performance. Interventions to promote and sustain better dietary quality over time can have substantial impacts on cognitive function.

Does adding MRI and CSF-based biomarkers improve cognitive status classification based on cognitive performance questionnaires?

BACKGROUND

Cognitive status classification (e.g. dementia, cognitive impairment without dementia, and normal) based on cognitive performance questionnaires has been widely used in population-based studies, providing insight into the population dynamics of dementia. However, researchers have raised concerns about the accuracy of cognitive assessments. MRI and CSF biomarkers may provide improved classification, but the potential improvement in classification in population-based studies is relatively unknown.

METHODS

Data come from the Alzheimer's Disease Neuroimaging Initiative (ADNI). We examined whether the addition of MRI and CSF biomarkers improved cognitive status classification based on cognitive status questionnaires (MMSE). We estimated several multinomial logistic regression models with different combinations of MMSE and CSF/MRI biomarkers. Based on these models, we also predicted prevalence of each cognitive status category using a model with MMSE only and a model with MMSE + MRI + CSF measures and compared them to diagnosed prevalence.

RESULTS

Our analysis showed a slight improvement in variance explained (pseudo-R2) between the model with MMSE only and the model including MMSE and MRI/CSF biomarkers; the pseudo-R2 increased from .401 to .445. Additionally, in evaluating differences in predicted prevalence for each cognitive status, we found a small improvement in the predicted prevalence of cognitively normal individuals between the MMSE only model and the model with MMSE and CSF/MRI biomarkers (3.1% improvement). We found no improvement in the correct prediction of dementia prevalence.

CONCLUSION

MRI and CSF biomarkers, while important for understanding dementia pathology in clinical research, were not found to substantially improve cognitive status classification based on cognitive status performance, which may limit adoption in population-based surveys due to costs, training, and invasiveness associated with their collection.

Nativity differences in the relationship between handgrip strength and cognitive impairment in older Mexican Americans over 20 years of follow-up

PURPOSE

To examine nativity differences in the relationship between handgrip strength (HGS) and cognitive impairment among Mexican Americans aged ≥ 65 years with normal or high cognitive function at baseline over a 20-year period.

METHODS

Prospective cohort study of 2,155 non-institutionalized Mexican Americans aged ≥ 65 years from the Hispanic Established Population for the Epidemiological Study of the Elderly) who scored ≥ 21 in the Mini Mental State Examination (MMSE) at baseline. Measures included socio-demographics, body mass index, medical conditions, depressive symptoms, physical function, disability, HGS quartiles (sex-adjusted), and MMSE. We used generalized estimating equation models to estimate the odds ratio (OR) and 95% Confidence Interval (CI) of cognitive impairment (MMSE < 21) as a function of HGS quartile by nativity and adjusted for covariates.

RESULTS

US-born and foreign-born participants in the 4th quartile (highest) of HGS at baseline had lower odds of cognitive impairment over time compared with those in the 1st (lowest) HGS quartile (OR=0.95, 95% CI=0.90-0.99 and OR=0.93, 95% CI=0.89-0.98, respectively), after controlling for all covariates. When we analyzed HGS quartiles as time-varying, we found that US-born participants in the 3rd and 4th HGS quartile had 25% and 30% lower odds of cognitive impairment, respectively, while foreign-born participants in the 3rd and 4th HGS quartile had 27% and 49% lower odds of cognitive impairment over time, respectively, after controlling for all covariates.

CONCLUSION

Foreign-born older Mexican Americans who performed high in HGS experienced 7% lower odds of cognitive impairment over time compared with US-born older Mexican Americans.

Temporal Dementia and Cognitive Impairment Trends in the Very Old in the 21st Century

BACKGROUND

Long-increasing dementia incidence and prevalence trends may be shifting. Whether such shifts have reached the very old is unknown.

OBJECTIVE

To investigate temporal trends in the incidence of dementia and cognitive impairment and prevalence of dementia, cognitive impairment, Alzheimer's disease, vascular dementia, and unclassified dementia among 85-, 90-, and ≥ 95-year-olds in Sweden during 2000-2017.

METHODS

This study was conducted with Umeå 85 + /Gerontological Regional Database data from 2182 85-, 90-, and ≥ 95-year-olds in Sweden collected in 2000-2017. Using logistic regression, trends in the cumulative 5-year incidences of dementia and cognitive impairment; prevalences of dementia, cognitive impairment, Alzheimer's disease, and vascular dementia; and Mini-Mental State Examination thresholds for dementia diagnosis were estimated.

RESULTS

Dementia and cognitive impairment incidences decreased in younger groups, which generally showed more-positive temporal trends. The prevalences of overall dementia, cognitive impairment, and Alzheimer's disease were stable or increasing; longer disease durations and increasing dementia subtype classification success may mask positive changes in incidences. Vascular dementia increased while unclassified dementia generally decreased.

CONCLUSION

The cognitive health of the very old may be changing in the 21st century, possibly indicating a trend break.

Establishing Healthy Eating 'Habits': A Pilot Randomised Controlled Trial of a Habit-Based Dietary Intervention following Oral Rehabilitation for Older Adults

An ageing population presents significant nutritional challenges, particularly for partially dentate adults. This two-armed pilot randomised controlled trial (RCT) compared habit formation (automaticity) for healthy eating behaviours between control and intervention groups after participation in a habit-based dietary intervention for older adults, following oral rehabilitation in the United Kingdom (UK). n = 54 participants were randomised to receive a habit-based dietary intervention (intervention group n = 27, IG) or standard dietary advice in a leaflet (control group n = 27, CG). The IG attended three sessions over six weeks, which focused on habit formation for three healthy eating behaviours (increasing fruit and vegetables, wholegrains, and healthy proteins). Participants were assessed for habit strength (using the Self-Report Behavioural Automaticity Index (SRBAI)) alongside health and nutrition outcomes at six weeks, four months and eight months. Forty-nine participants completed all follow-up visits. The IG compared to the CG had significant increases in automaticity at six weeks, four months (primary outcome) and eight months for eating ≥3 portions of fruit and vegetables; choosing wholegrain sources over white alternatives, and choosing healthy protein sources over red/processed meat. The mean change in the Mini Nutritional Assessment total score was greater in the IG compared with the CG at six weeks only (p = 0.03). A habit-based dietary intervention following oral rehabilitation increased automaticity for healthy dietary behaviours, which could translate into clinically meaningful benefits in this cohort of older adults.

The combined associations of depression and cognitive impairment with functional disability and mortality in older adults: a population-based study from the NHANES 2011-2014

Objective

The present study aimed to explore the combined associations of depression and cognitive impairment with functional disability and mortality, and whether the joint effects of depression and cognitive impairment on mortality were influenced by functional disability.

Methods

A total of 2,345 participants aged 60 and above from the 2011-2014 cycle of the National Health and Nutrition Examination Survey (NHANES) were included in the analyses. Questionnaires were used to evaluated depression, global cognitive function and functional disability (including disability in activities of daily living (ADLs), instrumental activities of daily living (IADLs), leisure and social activities (LSA), lower extremity mobility (LEM), and general physical activity (GPA)). Mortality status was ascertained up to December 31, 2019. Multivariable logistic regression was performed to investigate the associations of depression and low global cognition with functional disability. Cox proportional hazards regression models were conducted to evaluate the effect of depression and low global cognition on mortality.

Results

Interactions between depression and low global cognition were observed when exploring associations of depression and low global cognition with IADLs disability, LEM disability, and cardiovascular mortality. Compared with normal participants, participants with both depression and low global cognition had the highest odds ratios of disability in ADLs, IADLs, LSA, LEM, and GPA. Besides, participants with both depression and low global cognition also had the highest hazard ratios of all-cause mortality and cardiovascular mortality, and these associations remained after adjusting for disability in ADLs, IADLs, LSA, LEM, and GPA.

Conclusion

Older adults with both depression and low global cognition were more likely to have functional disability, and had the highest risk of all-cause mortality and cardiovascular mortality.

Effect of cognitive impairment on risk of death in Hispanic/Latino adults over the age of 50 residing in the United States with and without diabetes: Data from the Health and Retirement Study 1995-2014

OBJECTIVE

To understand the relationship between mortality and cognitive function among older US Hispanic adults with and without diabetes.

METHODS

Data from the Health and Retirement Study (1995-2014) were analyzed. Cox proportional hazard models were used to estimate the association between mortality and cognitive function. Models were stratified by diabetes.

RESULTS

Four thousand thirteen older US Hispanic adults were included. Fully adjusted models for individuals with diabetes showed those with mild cognitive impairment (MCI; hazard ratio [HR]: 1.61; 95% confidence interval [CI]: 1.06, 2.45; P = .025) and dementia (HR: 2.14; 95% CI: 1.25, 3.67; P = .006) had increased mortality compared to normal cognition. Fully adjusted models for individuals without diabetes showed those with MCI (HR: 1.87; 95% CI: 1.28, 2.74; P = .001) and dementia (HR: 3.25; 95% CI: 1.91, 5.55; P < .001) had increased mortality compared to normal cognition.

CONCLUSIONS

Cognitive impairment is associated with increased mortality in older US Hispanic adults with and without diabetes. Clinicians should regularly assess cognitive function in this group to quickly identify declines and make appropriate referrals for support to optimize health and reduce mortality.

Cognitive Dysfunction in Heart Failure: Pathophysiology and Implications for Patient Management

PURPOSE OF REVIEW

There is increasing recognition of the prevalence and impact of cognitive dysfunction (CD) in heart failure (HF) patients. This contemporary review appraises the evidence for epidemiological association, direct pathophysiological links and emerging pharmacological and non-pharmacological interventions. Furthermore, we present evidence for care models that aim to mitigate the morbidity and poor quality of life associated with these dual processes and propose future work to improve outcomes.

RECENT FINDINGS

CD disproportionately affects heart failure patients, even accounting for known comorbid risk factors, and this may extend to subclinical left ventricular dysfunction. Neuroimaging studies now provide evidence of anatomical and functional differences which support previously postulated mechanisms of reduced cerebral blood flow, micro-embolism and systemic inflammation. Interventions such as multidisciplinary ambulatory HF care, education and memory training improve HF outcomes perhaps to a greater degree in those with comorbid CD. Additionally, optimisation of standard heart failure care (cardiac rehabilitation, pharmacological and device therapy) may lead to additional cognitive benefits. Epidemiological, neuroimaging and intervention studies provide evidence for the causal association between HF and CD, although evidence for Alzheimer's dementia is less certain. Specific reporting of cognitive outcomes in HF trials and evaluation of targeted interventions is required to further guide care provision.

Disparities in Subjective Cognitive Impairment by Sexual Orientation and Gender in a National Population Based Study of U.S. Adults, 2013-2018

Objectives: This is the first national population-based study to examine cognitive impairment disparities among sexual minority mid-life and older adults. Methods: Using the National Health Interview Survey (2013-2018), we compared weighted prevalence of subjective cognitive impairment by sexual orientation and gender, among those aged 45 plus, applying logistic regressions adjusting for age, income, education, race/ethnicity, and survey years. Results: Sexual minorities (24.5%) were more likely to have subjective cognitive impairment than heterosexuals (19.1%). Sexual minority women had higher odds of greater severity, frequency, and extent of subjective cognitive impairment. Sexual minorities were also more likely to report activity limitations resulting from cognitive impairment and were no more likely to attribute limitations to dementia or senility. Discussion: Cognitive health disparities are of particular concern in this historically and socially marginalized population. The investigation of explanatory factors is needed, and targeted interventions and policies are warranted to address cognitive challenges faced by sexual minorities.

Cognitive impairment and edentulism among older adults: an observational study using claims data

Background

The scientific link between mastication strength and cognitive function has not yet been strongly corroborated in population studies. Utilizing large-scale claims, we aim to investigate the association between edentulism and cognitive impairment in older American adults.

Methods

Using de-identified claims from a commercial insurer from 2015–2019, we conducted a retrospective cohort study using multilevel regression models to evaluate the association between denture status and clinically diagnosed cognitive impairment. Secondary analysis included symptomatic cognitive impairment in the outcome.

Results

Adjusting for individual-level risk factors, denture status was significantly associated with clinical cognitive impairment with odds ratios of 1.13 (95%CI: 1.02–1.25) and 1.26, (95%CI: 1.09–1.45) for complete dentures on one or both jaws, respectively. Including symptomatic cognitive impairment in the analysis did not substantially change our fundamental findings.

Conclusion

Prevention and treatment of oral diseases should be considered a key component in preserving the overall wellness of older adults.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12877-022-02985-w.

Spatial transcriptomic analysis reveals inflammatory foci defined by senescent cells in the white matter, hippocampi and cortical grey matter in the aged mouse brain

There is strong evidence that aging is associated with an increased presence of senescent cells in the brain. The finding that treatment with senolytic drugs improves cognitive performance of aged laboratory mice suggests that increased cellular senescence is causally linked to age-related cognitive decline. The relationship between senescent cells and their relative locations within the brain is critical to understanding the pathology of age-related cognitive decline and dementia. To assess spatial distribution of cellular senescence in the aged mouse brain, spatially resolved whole transcriptome mRNA expression was analyzed in sections of brains derived from young (3 months old) and aged (28 months old) C57BL/6 mice while capturing histological information in the same tissue section. Using this spatial transcriptomics (ST)-based method, microdomains containing senescent cells were identified on the basis of their senescence-related gene expression profiles (i.e., expression of the senescence marker cyclin-dependent kinase inhibitor p16INK4A encoded by the Cdkn2a gene) and were mapped to different anatomical brain regions. We confirmed that brain aging is associated with increased cellular senescence in the white matter, the hippocampi and the cortical grey matter. Transcriptional analysis of the senescent cell-containing ST spots shows that presence of senescent cells is associated with a gene expression signature suggestive of neuroinflammation. GO enrichment analysis of differentially expressed genes in the outer region of senescent cell-containing ST spots ("neighboring ST spots") also identified functions related to microglia activation and neuroinflammation. In conclusion, senescent cells accumulate with age in the white matter, the hippocampi and cortical grey matter and likely contribute to the genesis of inflammatory foci in a paracrine manner.

Brain oxygen extraction and neural tissue susceptibility are associated with cognitive impairment in older individuals

BACKGROUND AND PURPOSE

We investigated the effects of aging, white matter hyperintensities (WMH), and cognitive impairment on brain iron levels and cerebral oxygen metabolism, known to be altered in Alzheimer's disease (AD), using quantitative susceptibility mapping and MR-based cerebral oxygen extraction fraction (OEF).

METHODS

In 100 individuals over the age of 50 (68/32 cognitively impaired/intact), OEF and neural tissue susceptibility (χ_n ) were computed retrospectively from MRI multi-echo gradient echo data, obtained on a 3 Tesla MRI scanner. The effects of age and WMH on OEF and χ_n were assessed within groups, and OEF and χ_n were assessed between groups, using multivariate regression analyses.

RESULTS

Cognitively impaired subjects were found to have 19% higher OEF and 34% higher χ_n than cognitively intact subjects in the cortical gray matter and several frontal, temporal, and parietal regions (p < .05). Increased WMH burden was significantly associated with decreased OEF in the cognitively impaired, but not in the cognitively intact. Older age had a stronger association with decreased OEF in the cognitively intact group. Both older age and increased WMH burden were significantly associated with increased χ_n in temporoparietal regions in the cognitively impaired.

CONCLUSIONS

Higher brain OEF and χ_n in cognitively impaired older individuals may reflect altered oxygen metabolism and iron in areas with underlying AD pathology. Both age and WMH have associations with OEF and χ_n but are modified by the presence of cognitive impairment.

Race/Ethnic Differences, Skin Tone, and Memory Among Older Latinos in the United States

OBJECTIVES

U.S. Latino populations are diverse. Research on racial identity, skin tone, and Latino health is imperative for understanding and combating racism and colorism. We examined differences in memory performance: among non-Latinos and Latinos who identified as Black, other, and White in the United States and then among Puerto Ricans in Boston whose skin tones ranged from dark, medium, light to "white."

METHODS

We used 2010 Health and Retirement Study and 2004 Boston Puerto Rican Health Survey data, respectively, to examine racial and color differences in memory performance among 50 and older adults in the United States and Puerto Rican older adults in Boston. We applied ordinary least squares regression to immediate and delayed word recall test scores and adjusted for education, health conditions, and health behaviors.

RESULTS

In adjusted models, White non-Latinos had better memory performance than White Latinos. Black Latinos, other Latinos, and Black non-Latinos had lower delayed word recall scores than White Latinos. Black Latinos and Black non-Latinos had similar scores. Intra-Latino racial disparities endured despite the inclusion of education and other covariates. Among Puerto Ricans in Boston, medium-toned individuals had higher scores than "white"-toned individuals.

DISCUSSION

Findings support the importance of examining self-identified race and skin tone in Latino aging research. Further investigation is needed to understand the stubborn intra-Latino racial disparities in memory performance and surprising adverse cognitive performance among "white"-toned relative to darker-toned Puerto Ricans in Boston.

Secular Improvements in Cognitive Aging: Contribution of Education, Health, and Routine Activities

Objectives

Limited evidence exists regarding the reasons for secular changes in cognitive functioning over historical time. Thus, we examined potential explanatory factors for changes in cognitive speed, a central dimension of cognitive functioning.

Methods

Population-based data of middle-aged and older adults from Germany (N = 5443) was used with baseline participants from 2002 to 2014, comparing the time periods 2002–2014.

Results

Cognitive speed improved in middle-aged adults (40–65) and older adults (66+). In both age groups, increases were partly explained by education, employment status, volunteering status, routine activities, and physical functioning. Changes in education were more important in explaining increases in older than in middle-aged adults, whereas changes in health were more important for explaining increases in middle-aged adults.

Conclusions

Cognitive speed increased in both age groups over historical time. Education, employment, volunteering, routine activities, and health were all important in explaining these changes, but their importance differed between age groups.

Independent associations between sleep duration, gamma gap, and cognitive function among older adults: Results from the NHANES 2013-2014

This study examined whether gamma gap mediated the association between sleep and cognitive function. Data from NHANES 2013-2014 were used. Three tests were used to measure cognitive function. Sleep was measured by three single questions. Gamma gap was calculated by subtracting albumin from total protein. Participants were 1392 older adults (53.2% females). Approximately 12% reported being told having sleep disorder, 1/3 reported having trouble sleeping, 25.9% had short sleep, and 12.5% had long sleep. Sleep disorders and sleep quality were not associated with cognitive function. Long sleep duration was an independent risk factor of reduced cognitive function on immediate recall, delayed recall, and executive function. Elevated gamma gap was also an independent risk factor of lower cognitive function. In a representative sample of older adults in the US, gamma gap and sleep duration were independent predictors of cognitive function. This study highlights the need for sleep assessment among older adults.

Daily Physical Activity Patterns as a Window on Cognitive Diagnosis in the Baltimore Longitudinal Study of Aging (BLSA)

BACKGROUND

Gradual disengagement from daily physical activity (PA) could signal present or emerging mild cognitive impairment (MCI) or Alzheimer's disease (AD).

OBJECTIVE

This study examined whether accelerometry-derived patterns of everyday movement differ by cognitive diagnosis in participants of the Baltimore Longitudinal Study of Aging (BLSA).

METHODS

Activity patterns, overall and by time-of-day, were cross-sectionally compared between participants with adjudicated normal cognition (n = 549) and MCI/AD diagnoses (n = 36; 5 participants [14%] living with AD) using covariate-adjusted regression models.

RESULTS

Compared to those with normal cognition, those with MCI/AD had 2.1% higher activity fragmentation (SE = 1.0%, p = 0.036) but similar mean total activity counts/day (p = 0.075) and minutes/day spent active (p = 0.174). Time-of-day analyses show MCI/AD participants had lower activity counts and minutes spent active during waking hours (6:00 am-5:59 pm; p < 0.01 for all). Also, they had lower activity fragmentation from 12:00-5:59 am (p < 0.001), but higher fragmentation from 12:00-5:59 pm (p = 0.026).

CONCLUSION

Differences in the timing and patterns of physical activity throughout the day linked to MCI/AD diagnoses warrant further investigation into potential clinical utility.

Trends in Dementia Prevalence, Incidence, and Mortality in the United States (2000-2016)

Objectives: The prevalence of dementia has declined in the United States; how this parallels to changes in incidence and mortality, and how improvements in educational attainment may have influences these trends, is not known. Methods: Using the Health and Retirement Study (2000-2016), we estimated logistic regression models to examine trends in dementia prevalence and incidence, and mortality for those with and without dementia. Results: The relative decline was about 2.4% per year for dementia prevalence and 1.9% for dementia incidence. Mortality declined similarly for those with and without dementia. Improved educational attainment accounted for decline in incidence, some of the decline in prevalence, and had a negligible role in mortality. Discussion: The declines in dementia incidence provide evidence that dementia prevalence should continue to decline in the near future. These declines are most likely largely driven by continued improvements in older adult education.

Religious attendance and global cognitive function: A fixed-effects cross-lagged panel modeling study of older U.S. adults

OBJECTIVES

Evidence linking religious attendance to better cognitive function is based on flawed study designs. No population representative longitudinal studies on the topic have taken both unobserved confounding and reverse causation into account. Recently developed fixed-effects cross-lagged panel modeling (FE-CLPM) offers simultaneous traction on these issues. It also allows parsing of long-from short-run effects. Using FE-CLPM and ten-year data from the Health and Retirement Study-a national probability sample of U.S. adults over age 50-this study began to fill the gaps above.

METHODS

Gender-specific FE-CLPM models were used to examine bidirectional and within-person linkages of religious attendance with global cognitive function. Granger-Sims "causality" tests further examined short-run effects in both directions. Impulse response analysis was used to explore time patterns in these linkages.

RESULTS

At least among women, religious attendance had negative short-term prospective linkages with global cognitive function. Over successive time points, these associations increased in strength among both genders. Feedback effects-of cognitive status on religious attendance-were found in both women's and men's models, but had a gender-specific pattern.

DISCUSSION

Results contradict a large literature positing cognitive benefits of religiosity. Instead, they lend support to a recent "neural resource depletion" model-especially among women. Overall, findings illustrate the "dark side" of religious engagement, which studies increasingly present as a social determinant with "outcome wide" positive effects on multiple health dimensions.

Changes in prevalence of cognitive impairment and associated risk factors 2000-2015 in São Paulo, Brazil

INTRODUCTION

Decreases in prevalence of cognitive impairment and dementia over the last two decades have been observed in different countries for cohorts entering older age. This study aimed to assess the cognitive impairment prevalence and explore associated factors among subjects aged >60 living in São Paulo, Brazil.

METHOD

Data came from a population-based Health, Welfare and Aging survey conducted in 2000, 2006, 2010, and 2015. Cognitive impairment was detected using the abbreviated Mini-Mental State Exam corrected by formal education years. In total, there were 5922 respondents in the statistical analyses.

RESULTS

Logistic regression models adjusted for age group, income, race, cardiovascular risk factors, and depression were used to estimate cognitive impairment prevalence. Between 2015 and 2000, respondents were more likely to report formal education, hypertension, diabetes, and overweight/obesity. Moreover, the weighted analyses showed that cognitive impairment prevalence was higher in 2015, even adjusting for sociodemographic and socioeconomic characteristics, cardiovascular risk factors, and depression.

CONCLUSION

In contrast to decreases in cognitive impairment prevalence in other countries and despite increases in educational years, our findings suggest no secular improvements in cognitive health for the 2015 wave of older adults residing in São Paulo.

Alterations in the gut microbiota contribute to cognitive impairment induced by the ketogenic diet and hypoxia

Many genetic and environmental factors increase susceptibility to cognitive impairment (CI), and the gut microbiome is increasingly implicated. However, the identity of gut microbes associated with CI risk, their effects on CI, and their mechanisms remain unclear. Here, we show that a carbohydrate-restricted (ketogenic) diet potentiates CI induced by intermittent hypoxia in mice and alters the gut microbiota. Depleting the microbiome reduces CI, whereas transplantation of the risk-associated microbiome or monocolonization with Bilophila wadsworthia confers CI in mice fed a standard diet. B. wadsworthia and the risk-associated microbiome disrupt hippocampal synaptic plasticity, neurogenesis, and gene expression. The CI is associated with microbiome-dependent increases in intestinal interferon-gamma (IFNg)-producing Th1 cells. Inhibiting Th1 cell development abrogates the adverse effects of both B. wadsworthia and environmental risk factors on CI. Together, these findings identify select gut bacteria that contribute to environmental risk for CI in mice by promoting inflammation and hippocampal dysfunction.

A 9-Year Comparison of Dementia Prevalence in Korea: Results of NaSDEK 2008 and 2017

BACKGROUND

In many high-income Western countries, the prevalence of dementia had been reduced over the past decades.

OBJECTIVE

We investigated whether the prevalence of all-cause dementia, Alzheimer's disease, vascular dementia, and mild cognitive impairment (MCI) had changed in Korea from 2008 to 2017.

METHODS

Nationwide Survey on Dementia Epidemiology of Korea (NaSDEK) in 2008 and 2017 was conducted on representative elderly populations that were randomly sampled across South Korea. Both surveys employed a two-stage design (screening and diagnostic phases) and diagnosed dementia and MCI according to the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders and the consensus criteria from the International Working Group, respectively. The numbers of participants aged 65 years or older in the screening and diagnostic phases were 6,141 and 1,673 in the NaSDEK 2008 and 2,972 and 474 in the NaSDEK 2017, respectively.

RESULTS

The age- and sex-standardized prevalence of all-cause dementia and Alzheimer's disease showed nonsignificant decrease (12.3% to 9.8%, odds ratio [OR] = 0.89, 95% confidence interval [CI] = 0.54-1.48 for all-cause dementia; 7.6% to 6.8%, OR [95% CI] = 0.91 [0.58-1.42] for Alzheimer's disease). Vascular dementia decreased in the young-old population aged less than 75 years (2.7% to 0.001%, OR [95% CI] = 0.04 [0.01-0.15]) and in women (1.9% to 0.5%, OR [95% CI] = 0.27 [0.10-0.72]) while MCI remained stable (25.3% to 26.2%, OR [95% CI] = 1.08 [0.67-1.73]).

CONCLUSION

We found that the prevalence of dementia in Korea showed a nonsignificant decrease between 2008 and 2017.

Rejoinder to "The Prevalence of Cognitive Impairment Is Not Increasing in the United States: A Critique of Hale et al. (2020)"

Supplemental Digital Content is available in the text.

The Prevalence of Cognitive Impairment Is Not Increasing in the United States: A Critique of Hale et al. (2020)

Previous research based on the longitudinal Health and Retirement Study (HRS) has argued that the prevalence of cognitive impairment has declined in recent years in the United States. A recent article published in Epidemiology by Hale et al., however, suggests this finding is biased by unmeasured panel conditioning (improvement in cognitive scores resulting from repeat assessment). After adjusting for test number, Hale and colleagues found that the prevalence of cognitive impairment had actually increased between 1996 and 2014. In this commentary, we argue that simply adjusting for test number is not an appropriate way to handle panel conditioning in this instance because it fails to account for selective attrition (the tendency for cognitively high-functioning respondents to remain in the sample for a longer time). We reanalyze HRS data using models that simultaneously adjust for panel conditioning and selective attrition. Contrary to Hale et al., we find that the prevalence of cognitive impairment has indeed declined in the United States in recent decades.

Prevalence and Outcomes of Major Psychiatric Disorders Preceding Index Surgery for Degenerative Thoracic/Lumbar Spine Disease

The relationship between preexisting major psychiatric disorders and outcomes of spine surgery for degenerative thoracic/lumbar disease remains unclear. A 5% subset of inpatients was randomly selected from the Taiwan National Health Insurance Research Database. A total of 10,109 inpatients aged 18 years or over with degenerative thoracic/lumbar disease and underwent spine surgery met inclusion criteria. Major psychiatric disorders diagnosed by psychiatrists preceding index surgery, including anxiety disorder, depression disorder, bipolar disorder, schizophrenia and dementia, were identified. The prevalence of psychiatric disorders, and their differential risks on in-hospital and post-discharge outcomes were examined. 10.4% had major psychiatric disorders, of which depression (6.6%) and anxiety (4.9%) were most common. Logistic regression revealed increased risks of ventilator use in depression (OR = 1.62, 95% CI = 1.04-2.54, p < 0.05), extended hospitalization length in bipolar (OR = 1.77, 95% CI = 1.08-2.89, p < 0.05), and higher rehabilitation utilization in depression (OR = 1.25, 95% CI = 1.06-1.47, p < 0.01) and bipolar (OR = 1.69, 95% CI = 1.04-2.76, p < 0.05). Those patients with anxiety had a decreased risk of longer hospitalization duration (OR = 0.77, 95% CI = 0.60-0.98, p < 0.05), while those with dementia and schizophrenia had no change in risks. Preoperative recognition of major psychiatric disorders for risk and treatment assessment is suggested as people with preexisting depression or bipolar disorder have worse outcomes after spine surgery.

Decreasing trend in the incidence and prevalence of dementia: a systematic review

INTRODUCTION

The progressive ageing of the population is one of the main socio-demographic phenomena, taking place at a global level. Several recent population-based studies conducted worldwide suggest that the age-specific risk of dementia may be changing in some countries and areas.

EVIDENCE ACQUISITION

This systematic review was performed using the methodology proposed by the Cochrane handbook for systematic reviews and reported following the PRISMA statement. A structured bibliographic search was performed on the databases PubMed, ISI Web of Science and the Cochrane Database of Systematic Reviews. All included studies were qualitatively assessed using the Methodological Evaluation of Observational REsearch (MORE).

EVIDENCE SYNTHESIS

The bibliographic search yielded 2394 records. Three more articles were retrieved from other sources. A total of ten studies were included, five reported data on a possible reduction in the prevalence of dementia, and five reported data on a possible reduction in its incidence.

CONCLUSIONS

The present systematic review focused on the recent observations of a possible decrease in the frequency of dementia and cognitive impairment in some Western countries (USA, UK, Sweden, the Netherlands, France, Iceland) between 1977 and 2014. The included studies have a high heterogeneity in terms of the clinical criteria used to diagnose dementia, and of the criteria used to define the clinical condition preceding dementia, such as isolated cognitive impairment. Moreover, the methodological quality with which they were conducted was also heterogeneous, with scores ranging from 1 to 7 using the MORE tool.

Sex Differences in Cardiovascular Disease and Cognitive Dysfunction in Rural West Elderly Texans

BACKGROUND

The prevalence of cognitive dysfunction increases in elderly due to cardiovascular disease related risk factors in rural communities like West Texas.

OBJECTIVE

The purpose of this study was to find risk factors of cardiovascular disease (CVD) related to cognitive dysfunction and their impact on elderly adults in rural West Texans.

METHODS

Statistical methods such as Pearson's chi-squared and a multinomial logistic regression were utilized to analyze data. We used SPSS software to detect and understand the nature of the risk factors.

RESULTS

A summary of statistics was obtained by using Pearson's chi-squared test for categorical variables. CVD, diabetes mellitus, and depression were significantly associated with cognitive dysfunction for both males and females (p = 0.0001), whereas anxiety was found to be significantly associated with cognitive dysfunction for females (p = 0.0001). Age group and race/ethnicity were significantly associated with cognitive dysfunction for both males and females (p = 0.0001). By performing a multinomial logistic regression method and controlling for confounders, the significant risk factors (p <  0.05)- age (65- 84 years), diabetes, and memory loss for age-associated cognitive impairment; diabetes for cognitive impairment no dementia; age (65- 84, ≥85 years), CVD, diabetes, depression, memory loss, non-Hispanic Whites, and Black/African-Americans for mild cognitive impairment; and age, memory loss, non-Hispanic Whites, Black/African-Americans, and male gender were found for dementia.

CONCLUSION

CVD related risk factors in developing cognitive dysfunction exist and integrating such risk variables may guide relevant policy interventions to reduce Alzheimer's incidence or dementia in rural communities in West Texans.

Live longer, retire later? Developments of healthy life expectancies and working life expectancies between age 50–59 and age 60–69 in Europe

Europe’s population is ageing. Statutory retirement ages are commonly raised to account for continuous increases in life expectancy. In order to estimate the potential to increase statutory and consequently effective retirement ages further, in this study, we investigate the relationship between partial working life expectancy (WLE) and three health expectancies that represent health aspects important for work ability and employability between ages 50 and 59 as well as 60 and 69 for women and men in Europe. We also explore the association between these four indicators and the highest level of educational attainment. We apply Sullivan’s method to estimate WLE and three selected measures that capture general, physical, and cognitive health status of older adults for 26 European countries since 2004. Over time, WLEs increased significantly in the younger age group for women and in the older age group for both sexes. The expected number of years in good physical health have continuously been higher than any of the other three indicators, while the expected number of years in good cognitive health have shown a noticeable increase over time. The investigation of the relationship between education and each life expectancy confirms the well-established positive correlation between education and economic activity as well as good health. Our results indicate potential to extend working lives beyond current levels. However, significant differences in the expected number of years in good health between persons with different levels of education require policies that account for this heterogeneity.