Does personality affect risk for dementia? A systematic review and meta-analysis

Neuroticism personality, social contact, and dementia risk: A prospective cohort study

BACKGROUND

Personality traits, especially neuroticism, can influence susceptibility to dementia. Social contact mitigates stress and risk of dementia, the extent to which social contact can mitigate excess risk associated with neuroticism remains unclear. We aim to investigate whether active social contact is associated with lower neuroticism-associated excess risk of dementia.

METHODS

This prospective cohort study examined 393,939 UK Biobank participants (mean [SD] age: 56.4 [8.1] years; 53.7 % female) assessed from 2006 to 2010 and followed up until December 2022. Neuroticism was measured using the Revised Eysenck Personality Questionnaire. Social contact levels were assessed based on household size, contact with family or friends, and group participation. Dementia was determined using linked electronic health records.

RESULTS

High neuroticism was associated with increased all-cause dementia risk and cause-specific dementia. Among high neuroticism participants, excess risk of all-cause dementia showed a stepwise decrease with increasing social contact (low: hazard ratios (HR) = 1.27, 95 % confidence interval (CI) = 1.15-1.40; intermediate: HR = 1.20, 95 % CI = 1.12-1.28; high: HR = 1.07, 95 % CI = 1.00-1.15). High social contact similarly decreased excess risk of cause-specific dementia, comparable to those with low neuroticism.

LIMITATIONS

Neuroticism and social contact information relied on self-report questionnaires at baseline, with a potential temporal relationship between these factors.

CONCLUSION

Active social contact is associated with a stepwise reduction in excess dementia risk and potentially eliminate excess risk of dementia with high neuroticism individuals, supporting social contact as a preventive strategy to attenuate excess risks of dementia from neuroticism personality trait.

Contributions of loneliness to cognitive impairment and dementia in older adults are independent of other risk factors and Alzheimer's pathology: a narrative review

Loneliness significantly contributes to cognitive impairment and dementia in older adults. Loneliness is a distressing feeling resulting from a perceived lack of social connection (i.e., a discrepancy between desired and actual social relationships), while social isolation is a related term that can be defined by number and type of social relationships. Importantly, loneliness is distinct from social isolation in that it is associated with a distressing self-perception. The primary focus of this narrative review is the impact of chronic loneliness on cognitive impairment and dementia among older adults. Loneliness has a significant association with many factors that are related to worse cognition, and therefore we include discussion on health, mental health, as well as the physiological effects of loneliness, neuropathology, and potential treatments. Loneliness has been shown to be related to development of dementia with a hazard ratio (HR) risk comparable to having a single APOE4 gene. The relationship of dementia to loneliness appears to be at least partially independent of other known dementia risk factors that are possibly associated with loneliness, such as depression, educational status, social isolation, and physical activity. Episodic memory is not consistently impacted by loneliness, which would be more typically impaired if the mild cognitive impairment (MCI) or dementia was due to Alzheimer's disease (AD) pathology. In addition, the several longitudinal studies that included neuropathology showed no evidence for a relationship between loneliness and AD neuropathology. Loneliness may decrease resilience, or produce greater cognitive change associated with the same level of AD neuropathology. Intervention strategies to decrease loneliness in older adults have been developed but need to consider key treatment targets beyond social isolation. Loneliness needs to be assessed in all studies of cognitive decline in elders, since it significantly contributes to the variance of cognitive function. It will be useful to better define the underlying mechanism of loneliness effects on cognition to determine if it is similar to other psychological factors related to excessive stress reactivity, such as neuroticism or even depression, which are also associated with cognitive decline. It is important from a health perspective to develop better strategies to decrease loneliness in older adults.

Does social connection mediate the association between neuroticism and cognition? Cross-sectional analysis of the Canadian Longitudinal Study on Aging

OBJECTIVES

This study tested the association between neuroticism and six cognitive measures, and examined the potential mediating roles of social connection (social isolation and loneliness) among middle-aged and older adults.

METHODS

This cross-sectional study was a secondary analysis of the Canadian Longitudinal Study on Aging (CLSA) Comprehensive Cohort, a sample of Canadians aged 45-85 years at baseline. Respondents with data collected at the first follow-up, between 2015 and 2018, were included (n = 27,765). Structural equation modelling was used to assess the association between neuroticism and six cognitive measures (Rey Auditory Verbal Learning Test immediate recall and delayed recall, Animal Fluency Test, Mental Alternation Test, Controlled Oral Word Association Test and Stroop Test interference ratio), with direct and indirect effects (through social isolation and loneliness). All analyses were stratified by sex, including females (n = 14,133) and males (n = 13,632).

RESULTS

In unadjusted models, there was evidence of associations between neuroticism and all cognitive measures, except the Stroop Test interference ratio, suggesting higher neuroticism was associated with lower scores on memory and executive function tests. In the models of these other five outcomes, there was consistent evidence of indirect effects (through social isolation and loneliness) and, in some cases, direct effects. The results are discussed in context with limitations, including the use of cross-sectional design and alternative hypotheses to explain the association between personality and cognition.

CONCLUSION

Among middle-aged and older adults, for both males and females, the findings suggest that the association between neuroticism and cognitive outcomes may be mediated by aspects of social connection.

Revised Temperament and Character Inventory factors predict neuropsychiatric symptoms and aging-related cognitive decline across 25 years

Introduction

Personality traits and neuropsychiatric symptoms such as neuroticism and depression share genetic overlap and have both been identified as risks factors for development of aging-related neurocognitive decline and Alzheimer's disease (AD). This study aimed to examine revised personality factors derived from the Temperament and Character Inventory, previously shown to be associated with psychiatric disorders, as predictors of neuropsychiatric, cognitive, and brain trajectories of participants from a population-based aging study.

Methods

Mixed-effect linear regression analyses were conducted on data for the full sample (Nmax = 1,286), and a healthy subsample not converting to AD-dementia during 25-year follow-up (Nmax = 1,145), complemented with Cox proportional regression models to determine risk factors for conversion to clinical AD.

Results

Two personality factors, Closeness to Experience (CE: avoidance of new stimuli, high anxiety, pessimistic anticipation, low reward seeking) and Tendence to Liabilities (TL: inability to change, low autonomy, unaware of the value of their existence) were associated with higher levels of depressive symptoms, stress (CE), sleep disturbance (TL), as well as greater decline in memory, vocabulary and verbal fluency in the full sample. Higher CE was additionally associated with greater memory decline across 25 years in the healthy subsample, and faster right hippocampal volume reduction across 8 years in a neuroimaging subsample (N = 216). Most, but not all, personality-cognition associations persisted after controlling for diabetes, hypertension and cardiovascular disease. Concerning risks for conversion to AD, higher age, and APOE-ε4, but none of the personality measures, were significant predictors.

Conclusion

The results indicate that personality traits associated with psychiatric symptoms predict accelerated age-related neurocognitive declines even in the absence of neurodegenerative disease. The attenuation of some personality effects on cognition after adjustment for health indicators suggests that those effects may be partly mediated by somatic health. Taken together, the results further emphasize the importance of personality traits in neurocognitive aging and underscore the need for an integrative (biopsychosocial) perspective of normal and pathological age-related cognitive decline.

Premorbid personality traits as predictors for incident predementia syndromes: a multistate model approach

OBJECTIVE

Associations have been found between five-factor model (FFM) personality traits and risk of developing specific predementia syndromes such as subjective cognitive decline (SCD) and mild cognitive impairment (MCI). The aims of this study were to: 1) Compare baseline FFM traits between participants who transitioned from healthy cognition or SCD to amnestic MCI (aMCI) versus non-amnestic MCI (naMCI); and 2) Determine the relationship between FFM traits and risk of transition between predementia cognitive states.

METHODS

Participants were 562 older adults from the Einstein Aging Study, 378 of which had at least one follow-up assessment. Baseline data collected included levels of FFM personality traits, anxiety and depressive symptoms, medical history, performance on a cognitive battery, and demographics. Follow-up cognitive diagnoses were also recorded.

RESULTS

Mann-Whitney U tests revealed no differences in baseline levels of FFM personality traits between participants who developed aMCI compared to those who developed naMCI. A four-state multistate Markov model revealed that higher levels of conscientiousness were protective against developing SCD while higher levels of neuroticism resulted in an increased risk of developing SCD. Further, higher levels of extraversion were protective against developing naMCI.

CONCLUSIONS

FFM personality traits may be useful in improving predictions of who is at greatest risk for developing specific predementia syndromes. Information on these personality traits could enrich clinical trials by permitting trials to target individuals who are at greatest risk for developing specific forms of cognitive impairment. These results should be replicated in future studies with larger sample sizes and younger participants.

Causal association between colorectal cancer and Alzheimer's disease: a bidirectional two-sample mendelian randomization study

Background: Colorectal cancer and Alzheimer's disease are both common life-threatening diseases in the elderly population. Some studies suggest a possible inverse relationship between colorectal cancer and Alzheimer's disease, but real-world research is subject to many biases. We hope to clarify the causal relationship between the two through a bidirectional two-sample Mendelian randomization study. Methods: In our study, we used genetic summary data from large-scale genome-wide association studies to investigate the relationship between colorectal cancer and Alzheimer's disease. Our primary analysis employed the inverse-variance weighted method and we also used complementary techniques, including MR-Egger, weighted median estimator, and Maximum likelihood. We applied simex adjustment to the MR-Egger results. We also utilized the MRlap package to detect potential sample overlap and its impact on the bias of the results. In addition, we performed several sensitivity and heterogeneity analyses, to ensure the reliability of our results. Results: The combined effect size results of the inverse-variance weighted method indicate that colorectal cancer may decrease the incidence of Alzheimer's disease, with an odds ratio (OR) of 0.846 (95% CI: 0.762-0.929). Similar results were observed using other methods such as MR-Egger, weighted median estimator, and Maximum likelihood. On the other hand, Alzheimer's disease may slightly increase the incidence of colorectal cancer, with an OR of 1.014 (95% CI: 1.001-1.027). However, the results of one subgroup were not significant, and the results from MRlap indicated that sample overlap introduced bias into the results. Therefore, the results of the reverse validation are not reliable. The F-statistic for all SNPs was greater than 20. Four SNPs related to the outcome were excluded using Phenoscanner website but the adjustment did not affect the overall direction of the results. The results of these statistics were further validated by MR-PRESSO, funnel plots, leave-one-out analyses, Cochran's Q, demonstrating the reliability of the findings. Conclusion: According to the findings of this Mendelian randomization study, there appears to be a causal association between colorectal cancer and Alzheimer's disease. These results could have important implications for clinical practice in terms of how colorectal cancer and Alzheimer's disease are treated. To better understand the relationship between these two diseases, more research and screening are needed in clinical settings.

The association between lifelong personality and clinical phenotype in the FTD-ALS spectrum

Introduction

Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are two phenotypes of the same neurodegenerative disease, the FTD-ALS spectrum. What determines the development of one rather than the other phenotype is still unknown. Based on the clinical observation that patients' personality seems to differ between the two phenotypes, i.e., ALS patients tend to display kind, prosocial behaviors whereas FTD patients tend to present anti-social behaviors, and that these traits are often reported as pre-existing the disease onset by caregivers, we set up to study experimentally patients' personality in their premorbid life.

Methods

We first tested for differences between groups, then tested the association between premorbid personality and current functional organization of the brain. Premorbid personality of a cohort of forty patients, 27 FTD and 13 ALS, was explored through the NEO Personality Inventory 3 (NEO-PI-3), which analyses the five main personality factors, completed by the caregiver with reference to patient's personality 20 years before symptoms onset (premorbid). A subgroup of patients underwent a brain MRI including structural and resting-state functional MRI (rsfMRI).

Results

A significant difference between FTD and ALS in premorbid personality emerged in the Openness (133.92 FTD vs. 149.84 ALS, p = 0.01) and Extraversion (136.55 FTD vs. 150.53 ALS, p = 0.04) factors. This suggests that ALS patients had been, in their premorbid life, more open to new experiences, more sociable and optimistic than FTD patients. They also showed greater functional connectivity than both FTD and a control group in the Salience resting state network, over and above differences in gray matter atrophy. Finally, there was a positive correlation between premorbid Openness and functional connectivity in the Salience network across all patients, suggesting a possible association between premorbid personality and current functional organization of the brain, irrespective of the degree of atrophy.

Discussion

Our proof-of-concept results suggest that premorbid personality may eventually predispose to the development of one, rather than the other, phenotype in the FTD-ALS spectrum.

Identifying modifiable factors and their joint effect on dementia risk in the UK Biobank

Previous hypothesis-driven research has identified many risk factors linked to dementia. However, the multiplicity and co-occurrence of risk factors have been underestimated. Here we analysed data of 344,324 participants from the UK Biobank with 15 yr of follow-up data for 210 modifiable risk factors. We first conducted an exposure-wide association study and then combined factors associated with dementia to generate composite scores for different domains. We then evaluated their joint associations with dementia in a multivariate Cox model. We estimated the potential impact of eliminating the unfavourable profiles of risk domains on dementia using population attributable fraction. The associations varied by domain, with lifestyle (16.6%), medical history (14.0%) and socioeconomic status (13.5%) contributing to the majority of dementia cases. Overall, we estimated that up to 47.0%-72.6% of dementia cases could be prevented.

The relationship between optimism, MCI, and dementia among postmenopausal women

OBJECTIVES

The relationship between optimism and cognitive functioning is not fully understood. We examined the association of optimism with risk of mild cognitive impairment (MCI) and dementia in the Women's Health Initiative Memory Study (WHIMS).

METHODS

Optimism was measured by the Life Orientation Test-Revised (LOT-R) total score, and optimism and pessimism subscales. A panel of experts adjudicated cognitive endpoints based on annual cognitive assessments. We used cox proportional hazard regression models to examine the association of LOT-R total score and optimism and pessimism sub-scores with MCI/dementia. We also examined the relationship between vascular disease, LOT-R total score, optimism and pessimism, and cognition.

RESULTS

Mean age was 70.5 (SD = 3.9) years. The sample (N = 7249) was 87% white, and 29.8% of participants had < 12 years of education. Total LOT-R score (HR = 0.96, 95% CI: 0.94, 0.98, p < 0.001) was associated with lower risk of combined MCI or dementia. More pessimism (HR = 1.08, 95% CI: 1.05, 1.11, p < 0.0001) was associated with higher risk of MCI or dementia after adjustment for ethnicity, education, vascular disease, and depression. No significant relationships emerged from the optimism subscale.

CONCLUSION

These data suggest that less pessimism, but not more optimism, was associated with a lower risk of MCI and dementia.

Gender, Personality, and Cognitive Resilience Against Early-Life Disadvantage

OBJECTIVES

Early-life disadvantage (ELD) relates to lower late-life cognition. However, personality factors, including having an internal locus of control (LOC) or a conscientious personality, relate to resilience and effective stress coping. We explore whether personality factors convey resilience against the negative effects of ELD on cognition, by gender, in Mexico.

METHODS

Using the 2015 Mexican Health and Aging Study, we estimated expected cognition using multiple ELD markers to identify a subsample in the lowest quartile of expected cognition given ELD (n = 2,086). In this subsample, we estimated cross-sectional associations between personality and having above-median observed cognitive ability (n = 522) using logistic regression.

RESULTS

Among those in the lowest quartile of expected cognition, a more internal LOC (β = 0.32 [men] and β = 0.44 [women]) and conscientious personality (β = 0.39 [men] and β = 0.17 [women]) were significantly associated with having above-median cognitive ability in models adjusted for demographic confounders. Larger benefits of conscientiousness were observed for men than women. Associations between personality and having above-median cognitive ability remained statistically significant after further adjustment for health, stress, and cognitive stimulation variables, regardless of gender.

DISCUSSION

Personality factors may convey resilience among individuals who experienced ELD, potentially breaking the link between ELD and worse late-life cognition. Structural factors and gender roles may affect how much women benefit from personality factors.

Personality traits and disorders in Alzheimer's disease

BACKGROUND

The relationships between axis II personality disorders and the normative personality traits were explored in the context of current and pre-morbid personality assessment in Alzheimer's disease (AD).

METHODS

The study was conducted with four groups who were administered the NEO-FFI and the PDQ-4+, in the form of individual interview sessions. Current personality measure: consisting of 44 female participants (AD group) and, the control group, consisting of 80 female participants from the population at large. Pre-morbid personality measure: AD group informants (n = 40); control group informants (n = 42).

RESULTS

The results are in line with the literature review and provide new research data. By factorial discriminant analysis, the current and pre-morbid personality variables that differentiate AD from control groups are identified. The personality traits variables are the best discriminators such as low agreeableness, low openness to experience, and high neuroticism, suggesting that the maladaptive personality functioning can be described extending the range of psychopathology to a dimensional approach.

CONCLUSIONS

The study of personality variables seems to suggest, in their inclusion, the possibility to increase sensitivity toward an assessment in AD.

Effects of Longitudinal Changes in Neuroticism and Stress on Cognitive Decline

OBJECTIVE

The relationships among depression, personality factors, stress, and cognitive decline in the elderly are complex. Depressed elders score higher in neuroticism than nondepressed older individuals. Independently, the presence of neuroticism and the number of stressful life events are each associated with worsening cognitive decline in depressed older adults. Yet little is known about combined effects of changes in neuroticism and changes in stress on cognitive decline among older depressed adults.

DESIGN

Longitudinal observational study.

SETTING

Academic Health Center.

PARTICIPANTS

The authors examined 62 participants in the Neurobiology of Late-life depression (NBOLD) study to test the hypothesis that, compared with older depressed subjects who experience improved neuroticism and lower psychosocial stressors over time, those with worsening neuroticism and greater psychosocial stressors will demonstrate more cognitive decline.

MEASUREMENTS

The authors measured neuroticism using the NEO-Personality Inventory-Revised at baseline and 1 year. Study psychiatrists measured depression using the Montgomery-Ǻsberg Depression Rating Scale. At annual assessments, subjects reported the number of psychosocial stressors in the prior year and completed a neuropsychological evaluation. Participants completed a detailed neuropsychological battery at baseline and annually over 3 years. The battery included a test of delayed story memory (Logical Memory-2 or LMII). The outcome 3-year change in cognitive scores was regressed against 3-year change scores of neuroticism and number of psychosocial stressors, plus their interaction, while adjusting for sex, age, race, education, baseline cognitive score, and 3-year change in MADRS score as covariates.

RESULTS

In multivariable linear regression analysis with the above covariates, the interaction effect of 3-year change in Total Neuroticism score and 3-year change in Total Stressors on change in LMII performance was statistically significant (B = -0.080[95%CL: -0.145 to -0.015], T = -2.48, df = 52, p = 0.017). Further exploration of this finding showed that 1) when total stressors increased by 2 or more over 3 years, LMII change was inversely associated with neuroticism change; and 2) when neuroticism improved less, LMII change score was inversely associated with total stressor change. There were no other significant interactions between stress and neuroticism on cognition.

CONCLUSION

Our findings document the importance of tracking change in neuroticism and monitoring psychosocial stress over the long-term course of treatment in geriatric depression. Both factors exert important combined effects on memory over time. Future studies in larger samples are needed to confirm our results and to extend them to examine both cognitive change and development of dementia.

Improving risk indexes for Alzheimer's disease and related dementias for use in midlife

Knowledge of a person’s risk for Alzheimer’s disease and related dementias (ADRDs) is required to triage candidates for preventive interventions, surveillance, and treatment trials. ADRD risk indexes exist for this purpose, but each includes only a subset of known risk factors. Information missing from published indexes could improve risk prediction. In the Dunedin Study of a population-representative New Zealand-based birth cohort followed to midlife (N = 938, 49.5% female), we compared associations of four leading risk indexes with midlife antecedents of ADRD against a novel benchmark index comprised of nearly all known ADRD risk factors, the Dunedin ADRD Risk Benchmark (DunedinARB). Existing indexes included the Cardiovascular Risk Factors, Aging, and Dementia index (CAIDE), LIfestyle for BRAin health index (LIBRA), Australian National University Alzheimer’s Disease Risk Index (ANU-ADRI), and risks selected by the Lancet Commission on Dementia. The Dunedin benchmark was comprised of 48 separate indicators of risk organized into 10 conceptually distinct risk domains. Midlife antecedents of ADRD treated as outcome measures included age-45 measures of brain structural integrity [magnetic resonance imaging-assessed: (i) machine-learning-algorithm-estimated brain age, (ii) log-transformed volume of white matter hyperintensities, and (iii) mean grey matter volume of the hippocampus] and measures of brain functional integrity [(i) objective cognitive function assessed via the Wechsler Adult Intelligence Scale-IV, (ii) subjective problems in everyday cognitive function, and (iii) objective cognitive decline measured as residualized change in cognitive scores from childhood to midlife on matched Weschler Intelligence scales]. All indexes were quantitatively distributed and proved informative about midlife antecedents of ADRD, including algorithm-estimated brain age (β's from 0.16 to 0.22), white matter hyperintensities volume (β's from 0.16 to 0.19), hippocampal volume (β's from −0.08 to −0.11), tested cognitive deficits (β's from −0.36 to −0.49), everyday cognitive problems (β's from 0.14 to 0.38), and longitudinal cognitive decline (β's from −0.18 to −0.26). Existing indexes compared favourably to the comprehensive benchmark in their association with the brain structural integrity measures but were outperformed in their association with the functional integrity measures, particularly subjective cognitive problems and tested cognitive decline. Results indicated that existing indexes could be improved with targeted additions, particularly of measures assessing socioeconomic status, physical and sensory function, epigenetic aging, and subjective overall health. Existing premorbid ADRD risk indexes perform well in identifying linear gradients of risk among members of the general population at midlife, even when they include only a small subset of potential risk factors. They could be improved, however, with targeted additions to more holistically capture the different facets of risk for this multiply determined, age-related disease.

Association of Self-reflection With Cognition and Brain Health in Cognitively Unimpaired Older Adults

BACKGROUND AND OBJECTIVES

Self-reflection (the active evaluation of ones thoughts, feelings, and behaviors) can confer protection against adverse health outcomes. Its effect on markers sensitive to Alzheimer disease (AD), however, is unknown. The primary objective of this cross-sectional study was to examine the association between self-reflection and AD-sensitive markers.

METHODS

This study used baseline data from cognitively unimpaired older adults enrolled in the Age-Well clinical trial and older adults with subjective cognitive decline from the SCD-Well clinical trial. In both cohorts, self-reflection was measured via the reflective pondering subscale of the Rumination Response Scale, global cognition assessed via the Preclinical Alzheimer's Cognitive Composite 5, and a modified late-life Lifestyle-for-Brain-Health (LIBRA) index computed to assess health and lifestyle factors. In Age-Well, glucose metabolism and amyloid deposition were quantified in AD-sensitive gray matter regions via fluorodeoxyglucose- and AV45-PET scans, respectively. Associations between self-reflection and AD-sensitive markers (global cognition, glucose metabolism, and amyloid deposition) were assessed via unadjusted and adjusted regressions. Furthermore, we explored whether associations were independent of health and lifestyle factors. To control for multiple comparisons in Age-Well, false discovery rate-corrected p values (p _FDR) are reported.

RESULTS

A total of 134 (mean age 69.3 ± 3.8 years, 61.9% women) Age-Well and 125 (mean age 72.6 ± 6.9 years, 65.6% women) SCD-Well participants were included. Across unadjusted and adjusted analyses, self-reflection was associated with better global cognition in both cohorts (Age-Well: adjusted-β = 0.22, 95% CI 0.05-0.40, p _FDR = 0.041; SCD-Well: adjusted-β = 0.18, 95% CI 0.03-0.33, p = 0.023) and with higher glucose metabolism in Age-Well after adjustment for all covariates (adjusted-β = 0.29, 95% CI 0.03-0.55, p _FDR = 0.041). Associations remained following additional adjustment for LIBRA but did not survive false discovery rate (FDR) correction. Self-reflection was not associated with amyloid deposition (adjusted-β = 0.13, 95% CI -0.07 to 0.34, p _FDR = 0.189).

DISCUSSION

Self-reflection was associated with better global cognition in 2 independent cohorts and with higher glucose metabolism after adjustment for covariates. There was weak evidence that relationships were independent from health and lifestyle behaviors. Longitudinal and experimental studies are warranted to elucidate whether self-reflection helps preserve cognition and glucose metabolism or whether reduced capacity to self-reflect is a harbinger of cognitive decline and glucose hypometabolism.

TRIAL REGISTRATION INFORMATION

Age-Well: NCT02977819; SCD-Well: NCT03005652.

Extraversion Is Associated With Lower Brain Beta-Amyloid Deposition in Cognitively Normal Older Adults

Emerging evidence suggests that some personality traits may link to the vulnerability to or protection for Alzheimer’s disease (AD). A causal mechanism underlying this relationship, however, remains largely unknown. Using 18F-Florbetaben positron emission tomography (PET) binding to beta-amyloid (Aβ) plaques, a pathological feature of AD, and functional magnetic resonance imaging (fMRI), we investigated pathological and functional correlates of extraversion and neuroticism in a group of healthy young and older subjects. We quantified the level of brain Aβ deposition in older individuals. Brain activity was measured in young adults using a task-switching fMRI paradigm. When we correlated personality scores of extraversion and neuroticism with these pathological and functional measures, higher extraversion, but not neuroticism, was significantly associated with lower global Aβ measures among older adults, accounting for age and sex. This association was present across widespread brain regions. Among young subjects, higher extraversion was associated with lower activity during task switching in the anterior cingulate cortex, left anterior insular cortex, left putamen, and middle frontal gyrus bilaterally, while higher neuroticism was associated with increased activity throughout the brain. The present results suggest that possibly via efficient neuronal activity, extraversion, one of the lifelong personality traits, may confer the protective mechanism against the development of Aβ pathology during aging.

Mediation of perceived stress and cortisol in the association between neuroticism and global cognition in older adults: A longitudinal study

Neuroticism has been associated with a greater dementia risk, but its association with cognitive decline in healthy older adults remains unclear. Stress has been proposed as one of the mechanisms that could explain this relationship. Our aim was to analyse, in healthy older people, the mediating role of perceived stress and the Hypothalamic-Pituitary-Adrenal (HPA) axis in the association between neuroticism and global cognition. At Waves 1 and 2 (4-year follow-up), 87 older people (49.4% women; M age = 65.08, SD = 4.54 at Wave 1) completed a neuropsychological battery and the Perceived Stress Scale (PSS), and provided saliva samples on two (Wave 1) and three (Wave 2) consecutive days to measure the wake-to-bed slope. In Wave 2, neuroticism was assessed with the NEO-Five-Factor Inventory. PSS, but not the wake-to-bed slope, mediated the negative associations between neuroticism and global cognition (Waves 1, 2 and change). Regarding gender differences, PSS (Waves 1, 2 and change) and the wake-to-bed slope (Wave 2 and change) mediated these associations in men. Our results suggest that perceived stress and HPA-axis dysregulation could act as mechanisms underlying the association between neuroticism and cognitive functioning and decline, at least in older men.

Data overuse in aging research: Emerging issues and potential solutions

Aging and lifespan development researchers have been fortunate to have public access to many longitudinal datasets. These data are valuable and see high utilization, yet this has a considerable downside. Many of these are heavily overused. Overuse of publicly available datasets creates dependency among published research papers giving the false impression of independent contributions to knowledge by reporting the same associations over multiple papers. This is a potentially serious problem in the aging literature given the high use of a relatively small number of well-known studies. Any irregularities or sampling biases in this relatively small number of samples have outsize influence on perceived answers to key aging questions. We detail this problem, focusing on issues of dependency among studies, sampling bias and overfitting, and contradictory estimates of the same effect from the same data in independent publications. We provide solutions, including greater use of data sharing, pre-registrations, holdout samples, split-sample cross-validation, and coordinated analysis. We argue these valuable datasets are public resources that are being diminished by overuse, with parallels in environmental science. Taking a conservation perspective, we hold that these practices (pre-registration, holdout samples) can preserve data resources for future generations of researchers. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Do Personality Traits Influence the Association Between Depression and Dementia in Old Age?

Depression and personality traits are independent predictors of dementia or cognitive impairment. Despite the well-established relationship between these two psychosocial factors and dementia, no research has been documented on how personality traits can influence dementia in older adults exhibiting depressive symptoms. This study explores the influence of personality traits on the association between change in depression and dementia in old age. A population-based longitudinal cohort study involving two waves of data collected 5 years apart, containing 2210 American older adults, from the National Social Life, Health, and Aging Project to explore if personality traits influence how change in depression predicts the development of dementia. We assessed these relationships while adjusting for sociodemographic characteristics. Change in depression increased the likelihood of dementia at T2 by 4.2% (AOR = 1.04, p = 0.019) in the co-variate adjusted model. Personality traits, overall, did not influence how depression predicts the development of dementia. However, agreeableness individually nullified the effect of depression on the development of dementia, whereas extraversion was the only personality trait that significantly predicted dementia. Prosocial behaviors should be promoted in old age as these appear to be protective. In addition, early life education and a strong social support can keep the depression–dementia spectrum at bay in old age.

Exploring Cortical Proteins Underlying the Relation of Neuroticism to Cognitive Resilience

Some individuals maintain cognitive health despite neuropathology. Targets impacting "cognitive resilience" may provide interventions for preventing dementia without decreasing neuropathology. Neuroticism represents the tendency to experience negative emotions, and is related to worse cognitive resilience. Exploring proteins associated with cognitive resilience risk factors, such as neuroticism, could yield new protein targets. We used 355 postmortem prefrontal cortex from two cohorts to measure 8356 proteins. We identified (i) proteins associated with both neuroticism and cognitive resilience, and (ii) proteins statistically mediating relations of neuroticism to cognitive resilience. We found two proteins, 40S ribosomal proteinS3 (RPS3) and branched chain keto acid dehydrogenase E1, subunit beta (BCKDHB), ranked in the top 1% of smallest p-values in parallel linear regression models of neuroticism to protein levels, and protein levels to cognitive decline resilience. In mediation models, RPS3 and BCKDHB accounted for 25% (p=0.005) of the relation of neuroticism to cognitive resilience. Our sample size is modest, thus results may be due to chance (p-values did not meet Bonferroni significance) and will require further confirmation; however, investigating biologic mediators of associations of risk factors to cognitive resilience may help discover targets to promote cognitive resilience and reduce dementia.

Personality Impact on Alzheimer's Disease-Signature and Vascular Imaging Markers: A PET-MRI Study

BACKGROUND

Several studies postulated that personality is an independent determinant of cognitive trajectories in old age.

OBJECTIVE

This study explores the impact of personality on widely used Alzheimer's disease (AD) and vascular imaging markers.

METHODS

We examined the association between personality and three classical AD imaging markers (centiloid-based-amyloid load, MRI volumetry in hippocampus, and media temporal lobe atrophy), and two vascular MRI parameters (Fazekas score and number of cortical microbleeds) assessed at baseline and upon a 54-month-follow-up. Personality was assessed with the Neuroticism Extraversion Openness Personality Inventory-Revised. Regression models were used to identify predictors of imaging markers including sex, personality factors, presence of APOE ɛ4 allele and cognitive evolution over time.

RESULTS

Cortical GM volumes were negatively associated with higher levels of Conscientiousness both at baseline and follow-up. In contrast, higher scores of Openness were related to better preservation of left hippocampal volumes in these two time points and negatively associated with medial temporal atrophy at baseline. Amyloid load was not affected by personality factors. Cases with higher Extraversion scores displayed higher numbers of cortical microbleeds at baseline.

CONCLUSION

Personality impact on brain morphometry is detected only in some among the routinely used imaging markers. The most robust associations concern the positive role of high levels of Conscientiousness and Openness on AD-signature MRI markers. Higher extraversion levels are associated with increased vulnerability to cortical microbleeds pointing to the fact that the socially favorable traits may have a detrimental effect on brain integrity in old age.

Neuroticism predicts informant reported cognitive problems through health behaviors

OBJECTIVE

Personality traits have been linked to cognitive impairment, though work is needed to understand the mechanisms involved. Research also needs to consider alternative markers of cognitive impairment, such as informant report measures. The aim of the current study was to examine the role of health behaviors and social engagement as mediators for the relationship between personality and informant reported cognitive problems. It was expected that neuroticism would predict cognitive problems through negative health behaviors, while conscientiousness might predict cognitive problems through positive health behaviors.

METHODS

Using data from the St. Louis Personality and Aging Network study at three time points, spanning approximately 2.27 years (N = 829, M age = 65.95), correlations were computed between the Big Five personality traits and health behaviors at wave 1, social engagement at wave 2, and informant reported cognitive problems at wave 3. Mediation tests examined whether health behaviors and social engagement explained the relationships found between personality and informant reported cognitive problems.

RESULTS

Findings showed that neuroticism at wave 1 significantly predicted informant reported cognitive problems at wave 3 and that health behaviors, specifically wellness maintenance, partially explained this relationship. No significant associations were found between informant reported cognitive problems and conscientiousness, agreeableness, extraversion, openness, or social engagement.

CONCLUSION

This study supports claims that neuroticism predicts later cognitive problems and expands on previous literature by demonstrating this relationship using an informant report measure. Furthermore, we found that health behaviors, and specifically wellness maintenance, account for some of the relationship between neuroticism and informant reported cognitive problems.

Association of Stress with Risk of Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Although many studies have investigated the association between stress and risk of dementia, findings are inconsistent due to the variation in the measures used to assess stress.

OBJECTIVE

We conducted a systematic review and meta-analysis to investigate the association between psychological stress (including neuroticism, stressful life events, and perceived stress) and the risk of incident dementia and mild cognitive impairment in adults.

METHODS

PsycINFO, Embase, and MEDLINE were searched to October 2020 for eligible observational, prospective studies. Of the 1,607 studies screened, 26 (24 unique cohorts) were included in the qualitative analysis and 16 (15 unique cohorts) were included in the quantitative analysis.

RESULTS

Across studies, higher perceived stress was significantly associated with an increased risk of mild cognitive impairment (Cases/Total N = 207/860: hazard ratio [HR] = 1.19, 95% confidence interval [CI] = 1.03-1.38) and all-cause dementia (Cases/Total N = 203/1,882: HR = 1.44, 95% CI = 1.07-1.95). Exposure to two or more stressful life events (versus none) was significantly associated with an increased risk of all-cause dementia (Cases/Total N = 3,354/11,597: HR = 1.72, 95% CI = 1.14-2.60), while one or more stressful life events was not. Higher neuroticism was significantly associated with an increased risk of Alzheimer's disease dementia (Cases/Total N = 497/4,771: HR = 1.07, 95% CI = 1.01-1.12), but not all-cause dementia.

CONCLUSION

This review suggests that psychological stress in adulthood is associated with an increased risk of dementia. Further research is needed to clarify the mechanisms underlying these associations.

Depression-, Anxiety-, and Anger and Cognitive Functions: Findings From a Longitudinal Prospective Study

Background: Determinants of changes in cognitive function during aging are not well-understood. We aimed to estimate the effects of depression-, anxiety- and anger symptoms on cognition and on cognition changes, especially on changes in episodic memory (EM) and executive functioning (EF). Methods: We analyze data from the Mid-Life in the Midlife in the United States Biomarker study at two time points including n = 710 women, and n = 542 men (1996/1997) at the first assessment and n = 669 women, and n = 514 men at the second assessment (2013/2014). To assess cognition we used the Brief Test of Adult Cognition (BTACT). To measure depression-, anxiety- and anger symptoms we used the Mood and Anxiety Symptom Questionnaire (MASQ), the Center for Epidemiologic Studies Depression Scale (CES-D) and the State-Trait Anger Expression Inventory (STAXI). We used repeated models analyses to explore changes in cognition, and repeated measures linear mixed-effects models to investigate depression, anxiety and anger effects on cognition. All analyses were adjusted for potential confounders (cognition at baseline, age, education, income). Results: At the first assessment, women had significantly better episodic memory functioning than men; men in the oldest age group had significant better executive functioning. At the second assessment, more education, and white ethnicity were associated with less negative changes on episodic memory and executive functioning. Depression- and anger symptoms were associated with declines in episodic memory among women; anxiety symptoms were associated with declines in episodic memory and executive functioning in both gender in men (EF: β: -0.02, (95% CI: -0.03, -0.01; EM: β -0.02 (-0.02, 95% CI: -0.03, -0.01) and in women (EF: β -0.01, 95% CI: -0.02, -0.0004; EM: β -0.013, 95% CI: -0.03, -0.001). Conclusions: Depression-, anxiety- and anger symptoms were associated with changes in episodic memory and executive functioning. Further longitudinal studies are critical in populations in more countries to better understand the impact of depression, anxiety and anger symptoms on cognition changes.

Neuroticism, negative life events, and dementia in older White and Black Brazilians

OBJECTIVE

Exposure to negative life events (NLEs) and neuroticism are associated with dementia. It is unknown whether neuroticism explains or modifies the association of NLEs with dementia in older Black and White Brazilians.

METHODS

A total of 1747 decedents 65 years and older White and Black (11% Black and 23% Mixed) Brazilians, 53% women, were included in the analyses. Data were obtained in a face-to-face interview with an informant (71% their children) who knew the decedents for 47 years on average. Dementia was classified using the Clinical Dementia Rating. NLEs were assessed with a 10-item scale involving common problems (e.g., death, illness, alcoholism, and financial). Neuroticism was assessed with a 6-item neuroticism scale adapted from the NEO Five-Factor Inventory. Models adjusted for age, sex, and education. Black and mixed-race were combined in the analyses.

RESULTS

NLEs (median of 2) were more common in Blacks than Whites (2.04 vs. 1.82, p = 0.007). More NLEs increased the odds of dementia (OR = 1.112, β = 0.106, p = 0.002), similarly in Blacks and Whites (β interaction  = 0.046, p = 0.526). More NLEs were also associated with higher neuroticism (β = 0.071, p < 0.0001), in Whites but not in Blacks (β interaction  = -0.048, p = 0.006). Neuroticism was associated with higher odds of dementia (OR = 1.658, β = 0.506, p=<0.001), in Whites but not in Blacks (β interaction  = -0.420, p = 0.040). Overall, 34% of the effect of NLEs on dementia was associated with the underlying neuroticism trait in Whites (65%, Indirect OR = 1.060, p < 0.001) but no association was evident in Blacks (6%, Indirect OR = 1.008, p = 0.326). Neuroticism did not moderate the association of NLEs with dementia (OR = 0.979, β = -0.021, p = 0.717).

CONCLUSION

The association of NLEs and dementia is partially explained by neuroticism in older White but not in Blacks Brazilians.

Stress diagnoses in midlife and risk of dementia: a register-based follow-up study

OBJECTIVES

Previous studies indicated that stress diagnoses increase the risk of dementia. However, previous results may be biased by confounding, reverse causation and misclassification. Therefore, the main aim of this study was to investigate the association between clinically diagnosed stress in midlife and later dementia risk, while addressing limitations of previous studies.

METHODS

The study population was selected from all individuals in Denmark born 1935-1956. Individuals diagnosed with stress in midlife (aged 37-58 years) were matched (1:5) with individuals without stress diagnoses based on sex and birthdate (N = 103,484). Data were retrieved from national registers. Cox regression models were adjusted for socio-demographic factors and different morbidities.

RESULTS

We found a 2.20 (95% CI: 1.93-2.50) times higher rate of dementia among individuals with any stress diagnosis registered in midlife compared with no stress diagnosis. Hazard rate ratios of dementia were 1.73 (95% CI: 1.13-2.65) among individuals with acute stress reactions, 2.37 (95% CI: 2.05-2.74) among individuals with adjustment disorders, and 2.20 (95% CI: 1.73-2.80) among individuals with unspecified stress reactions. Individuals with PTSD and other stress reactions had non-significantly elevated rates of dementia. Adjustment for confounding only slightly attenuated the association, and reverse causation did not appear to bias the results substantially.

CONCLUSION

Our results support the hypothesis that severe stress in midlife is an important risk factor for dementia. This finding emphasizes the importance of identifying and treating severe stress in midlife to reduce potential detrimental consequences for brain health in later life.

Physical activity is associated with lower cerebral beta-amyloid and cognitive function benefits from lifetime experience-a study in exceptional aging

BACKGROUND

Exceptional agers (85+ years) are characterized by preserved cognition presumably due to high cognitive reserve. In the current study, we examined whether personality, risk and protective factors for dementia as well as quality of life are associated with core features of Alzheimer's disease (amyloid-deposition and hippocampal volume) as well as cognition in exceptional aging.

METHODS

We studied 49 exceptional agers (average 87.8 years, range 84-94 years), with preserved activities of daily living and absence of dementia. All participants received a detailed clinical and neuropsychological examination. We used established questionnaires to measure lifetime experience, personality, recent physical and cognitive activity as well as quality of life. Cerebral amyloid-deposition was estimated by 18-[F]-Flutemetamol-PET and manual hippocampal volumetry was performed on 3D T1 MRI images.

RESULTS

In this sample of exceptional agers with preserved activities of daily living, we found intact cognitive performance in the subjects with the highest amyloid-load in the brain, but a lower quality of life with respect to autonomy as well as higher neuroticism. Higher self-reported physical activity in the last twelve months went with a lower amyloid load. Higher self-reported leisure-time/ not work-related activity went with better executive functioning at older age.

CONCLUSION

Even in exceptional aging, high amyloid load may subtly influence personality and quality of life. Our findings support a close relationship between high physical activity and low amyloid-deposition and underscore the importance of extracurricular activities for executive functions. As executive functions are known to be a central resource for everyday functioning in fostering extracurricular activities may be effective in delaying the onset of dementia.

Associations Between Personality Traits and Cognitive Resilience in Older Adults

OBJECTIVES

The goal of this paper was to examine associations between personality traits and resilience to neuropathologic burden.

METHOD

Using data from the Religious Orders Study and the Rush Memory and Aging Project, we identified a total of 1,375 participants with personality, cognitive, and post-mortem neuropathology data. We regressed cognition onto pathology and extracted the residuals as an indicator of cognitive resilience. We then modeled the effect of Big Five personality traits on cognitive resilience, adjusting for demographics, APOE status, medical comorbidities, and cognitive activity. The analytic plan was preregistered prior to data access or analysis, and all scripts and outputs are available online.

RESULTS

Higher neuroticism was associated with greater vulnerability to pathology. Results from exploratory analyses suggest that higher conscientiousness was associated with less cognitive decline relative to the amount of pathology, or greater resilience. Education and cognitive activity did not moderate these associations.

DISCUSSION

Personality may have a pathoplastic effect on neuropathology, as low neuroticism and high conscientiousness are associated with better function despite neuropathologic burden.

Conscientiousness is associated with less amyloid deposition in cognitively normal aging

Little is known about the association between personality and Alzheimer's disease (AD) biomarkers, and existing results are inconsistent. We aimed to determine whether personality was associated with β-amyloid (Aβ) accumulation in cognitively normal aging. One hundred twenty-nine participants were included in this cross-sectional study. Personality was measured with the Big Five Inventory (BFI) and brain Aβ deposition was assessed with [11C] Pittsburgh compound B (PiB)-positron emission tomography (PET) imaging. Conscientiousness scores had a negative association with global PiB distribution volume ratio (DVR) in all participants after adjusting for age, sex, education, and vascular risk factors (β[SE] = -0.19[0.09], 95% confidence interval [CI: -0.35, -0.02], p = .031), while agreeableness, extraversion, neuroticism, and openness had no association with global PiB DVR. Assuming the relative stability of personality traits, these findings suggest that conscientiousness may protect against Aβ accumulation in cognitively normal aging through mechanisms that are as yet unknown. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Perceived stress and dementia: Results from the Copenhagen city heart study

Objectives: We investigated if perceived stress in midlife increased the risk of dementia. Furthermore, we explored differences between subgroups related to sex, age and employment status when reporting stress.Methods: In this longitudinal study, we used information on perceived stress from 10,814 participants (mean age 56.7 years). Participants were followed through Danish national registers for development of dementia. Participants were considered at risk of dementia from the date they turned 60 years. Perceived stress was assessed as a combination of self-reported intensity and frequency of stress, and categorized into low (score 0-1), medium (score 2-4), and high stress (score 5-6). We used Poisson regression to estimate incidence rate ratios (IRR) and their 95% confidence intervals (CI) and adjusted for sociodemographic factors and psychiatric morbidity at baseline (main model) as well as cardio/cerebrovascular diseases and health behaviors at baseline (additional model).Results: The mean follow-up time was 13.8 years, and 1,519 participants were registered with dementia. Dementia risk was higher in participants reporting medium stress (IRR = 1.11, 95% CI: 0.99-1.24) and high stress (IRR = 1.36, 95% CI: 1.13-1.65). Adjustment for cardio/cerebrovascular diseases and health behaviors did not alter the results. We did not find strong support for differences between subgroups, although the association between stress and dementia was stronger for those who were employed at the time of reporting high stress.Conclusion: Our results provide empirical support for an effect of perceived stress on the risk of dementia in old age.

Repetitive negative thinking is associated with subjective cognitive decline in older adults: a cross-sectional study

BACKGROUND

In the absence of a cure or effective treatment for dementia, attention has shifted towards identifying risk factors for prevention. Subjective Cognitive Decline (SCD) describes self-perceived worsening of cognition despite unimpaired performance on neuropsychological tests. SCD has been associated with an increased dementia risk and steeper memory decline. Repetitive negative thinking (RNT) is a transdiagnostic process that manifests across several mental health disorders associated with increased vulnerability to dementia. RNT has thus been proposed as a candidate marker of risk for dementia and, relatedly, could contribute to the manifestation of SCD. We aimed to investigate the relationship between SCD and RNT alongside other proposed psychological risk/protective factors for dementia and cognitive decline.

METHODS

In a cross-sectional online survey, 491 older adults (mean = 64.9 years, SD = 4.2; 63.1% female) completed measures of RNT, personality traits, purpose in life, worry, rumination, and meditation practice. SCD was assessed continuously via self-perceived cognitive function (Neuro-QoL) and categorically via endorsement (yes/no) of memory complaints. Regression models, using a stepwise backwards elimination, were built to assess associations between SCD, demographics, and all risk/protective factors.

RESULTS

A total of 24.2% of participants reported memory complaints. In the final prediction models, RNT was the only psychological variable associated with lower self-perceived cognitive function and with a higher likelihood of memory complaints.

CONCLUSIONS

This study empirically corroborates the theoretical relationship between SCD and RNT. Longitudinal studies are needed to establish whether RNT is a prodromal symptom or an independent risk factor, and whether RNT can be a promising construct for future research on SCD and dementia risk.

The relationship between cognitive reserve and personality traits: a pilot study on a healthy aging Italian sample

BACKGROUND

Exploring the role of different individual factors in affecting the cognitive reserve levels is crucial step for aging research. Several studies explored the relationship between personality traits and aging, but a specific focus on the cognitive reserve is missing.

AIMS

This study aimed at collecting more direct evidence about possible relationships between cognitive reserve and personality traits.

METHODS

A sample of 100 healthy aging participants was involved in the study. They completed the Big Five personality inventory and a test to assess the cognitive reserve.

RESULTS

Results returned a positive relationship between the personality traits and participants' cognitive reserve. The only factor that did not return a significant correlation was Emotional stability (which overlaps with Neuroticism).

DISCUSSION

This study provides additional evidence to the existing literature and also adds relevant information and a critical reading regarding the role of personality traits that has been neglected in the aging literature, Friendliness and Conscientiousness.

CONCLUSION

The ability to measure and identify personality traits could be important in future research for developing interventions or activities that could target specific personality characteristics.

Does Personality Predict Behavioral and Psychological Symptoms of Dementia? Results from PACO Prospective Study

BACKGROUND

Premorbid personality could play a role in the onset of behavioral and psychological symptoms (BPS) in Alzheimer's disease (AD) but prospective studies are lacking.

OBJECTIVE

The present study aimed at prospectively assessing the influence of premorbid personality traits on BPS evolution in a population of patients with prodromal or mild AD.

METHODS

We used a multicenter prospective cohort study of 237 patients followed-up for 18 months. The influence of personality traits on BPS evolution, measured with Neuropsychiatric Inventory (NPI), was assessed using linear mixed-effect models.

RESULTS

A principal components analysis of the 12 NPI behavioral domains yielded five factors labelled as psychotic symptoms, affective symptoms, behavioral dyscontrol, apathy/appetite symptoms, and sleep disorders. During the follow-up, higher neuroticism was significantly associated with a higher progression of affective symptoms (p < 0.0001), apathy/appetite symptoms (p = 0.002), sleep disorders (p = 0.001) as well as global NPI scores (p < 0.0001). Greater conscientiousness was related to a lower evolution of psychotic (p = 0.002), affective (p = 0.02) and apathy/appetite symptoms (p = 0.02), and global NPI score (p < 0.0001). Higher openness was associated with lower affective symptoms evolution (p = 0.01). A significant relationship was found between higher extraversion, lower affective symptoms (p = 0.02), and higher behavioral dyscontrol (p = 0.04).

CONCLUSION

The present analysis suggests that premorbid personality may influence the evolution of BPS in prodromal or mild AD. Given these results, it seems important to give more importance to personality assessment in early AD, in order to better identify and manage patients at risk of adverse behavioral changes.

Late-life personality traits, cognitive impairment, and mortality in a population-based cohort

OBJECTIVES

We examined longitudinal associations between late-life personality traits and cognitive impairment, dementia, and mortality in the population-based Cardiovascular Risk Factors, Aging and Dementia (CAIDE) Study.

METHODS

Anger expression and trait anger (State-Trait Anger Expression Inventory), anxiety (State-Trait Anxiety Inventory), and sense of coherence (Sense of Coherence Scale) were assessed at the 1998 CAIDE visit (1266 cognitively normal individuals, mean age 71.0 years). Totally, 582 participants had complete re-examination in 2005-2008 (105 mild cognitive impairment, MCI; and 29 dementia). National registers data until 2008 were also used for both participants and nonparticipants to ascertain incident dementia (96 cases) and mortality (227 died). Analyses were adjusted for age, sex, education, follow-up time, cardiovascular and lifestyle factors, and depressive symptoms.

RESULTS

Higher anxiety was associated with higher risk of MCI/dementia (OR 1.68, 95% CI 1.07-2.63) and death (HR 1.46, 95% CI 1.08-1.98). High sense of coherence was associated with lower mortality (HR 0.65, 95% CI 0.45-0.93). These associations were attenuated after accounting for depressive symptoms (OR 1.57, 95% CI 0.96-2.58 for anxiety-MCI/dementia; HR 1.35, 95% CI 0.97-1.86 for anxiety-mortality; and HR 0.68, 95% CI 0.45-1.04 for sense of coherence-mortality). Trait anger was associated with higher dementia risk even after adjustments (HR 1.90, 95% CI 1.14-3.18).

CONCLUSIONS

Anxiety was linked to worse cognitive outcome and mortality and sense of coherence to lower mortality. Depressive symptoms attenuated the associations. As a novel finding, trait anger was connected to dementia risk. These findings emphasize the importance of personality-related risk factors for dementia and mortality. J Am Geriatr Soc 68:-, 2020.

Personality and Hypothalamic-Pituitary-Adrenal Axis in Older Men and Women

Personality has been related to health and mortality risk, which has created interest in the biological pathways that could explain this relationship. Although a dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis has been associated with health outcomes and aging, few studies have explored the association between personality and HPA axis functioning in older adults. In addition, it has been suggested that sex could moderate the relationship between personality and HPA axis functioning. Thus, our aim was to analyze the relationship between the big five personality traits and the diurnal cortisol pattern in older adults, as well as sex differences in this relationship. To do so, 79 older people (40 men and 39 women) from 59 to 81 years old (M = 69.19, SD = 4.60) completed the NEO-Five-Factor Inventory (FFI) to measure neuroticism, conscientiousness, extraversion, openness, and agreeableness. Saliva samples were provided on three consecutive days (awakening; 15, 30, and 45 min post-awakening; and bedtime) in order to analyze the diurnal cortisol pattern and, specifically, two cortisol indexes: the cortisol awakening response (CAR) and the diurnal cortisol slope (DCS). Results showed that neuroticism and conscientiousness moderated the diurnal cortisol pattern. Thus, individuals with higher neuroticism and lower conscientiousness scores showed higher bedtime cortisol levels, suggesting a less healthy diurnal cortisol pattern. Regarding the cortisol indexes, higher neuroticism and lower conscientiousness were related to greater CAR and DCS. Sex moderated the association between extraversion and the DCS. Specifically, higher extraversion was related to a lower DCS only in women. Openness and agreeableness were not related to the diurnal cortisol pattern. In conclusion, our results show that in older adults, neuroticism is a vulnerability factor for HPA axis dysregulation, with possible adverse effects on health. By contrast, conscientiousness, and extraversion only in women, appear to be protective factors of HPA axis functioning, with potential beneficial effects on health.

Sekentei as a Socio-Cultural Determinant of Cognitive Function among Older Japanese People: Findings from the NEIGE Study

Sekentei (social appearance) is a Japanese concept that describes a person’s sense of implicit societal pressure to conform to social norms. However, evidence of a relationship between sekentei and health outcomes is sparse. This study examined the association between sekentei and cognitive function among community-dwelling older Japanese people. Baseline data were obtained from the Neuron to Environmental Impact across Generations (NEIGE) study conducted in 2017; 526 randomly sampled community-dwelling individuals aged 65–84 years living in Tokamachi, Niigata Prefecture, Japan were analyzed. The 12-item Sekentei Scale was used to assess sekentei. Cognitive function levels were evaluated with the Japanese version of Mini-Mental State Examination (MMSE-J; ranging from 0–30). Approximately 10% and 25% had cognitive decline and mild cognitive impairment, respectively (MMSE-J scores of ≤23 and 24–26, respectively). Multinomial logistic regression analysis showed that both high and low levels of sekentei were associated with lower cognitive function, particularly mild cognitive impairment, after adjusting for sociodemographic factors, health behaviors, health conditions, and genetic factors. The current findings suggest that a moderate level of sekentei consciousness is beneficial for cognitive health, and that sekentei could be an important socio-cultural factor affecting cognitive function.

The Effect of Personality Traits on Risk of Incident Pre-dementia Syndromes

OBJECTIVES

Personality traits have been shown to be associated with the risk of dementia; less is known about their association with pre-dementia syndromes. The aim of the present study was to examine the role of personality traits as predictors of incident pre-dementia, motoric cognitive risk (MCR), and mild cognitive impairment (MCI) syndromes.

DESIGN

We prospectively examined the association between five personality traits (neuroticism, extraversion, conscientiousness, agreeableness, and openness) and the risk of incident MCR or MCI. MCR builds on MCI operational definitions, substituting the cognitive impairment criterion with slow gait, and it is associated with increased risk for both Alzheimer's disease and vascular dementia.

SETTING

Community based.

PARTICIPANTS

Nondemented participants (n = 524; 62% women) aged 65 years and older.

MEASUREMENTS

Cox proportional hazard analysis, adjusted for demographics and disease burden, was used to evaluate the risk of each pre-dementia syndrome based on baseline personality traits, measured using the Big Five Inventory.

RESULTS

Over a median follow-up of 3 years, 38 participants developed incident MCR, and 69 developed incident MCI (41 non-amnestic and 28 amnestic subtypes). Openness was associated with a reduced risk of developing incident MCR (adjusted hazard ratio [aHR] = .94; 95% confidence interval [CI] = .89-.99), whereas neuroticism was associated with an increased risk of incident non-amnestic MCI (aHR = 1.06; 95% CI = 1.01-1.11). These associations remained significant even after considering the confounding effects of lifestyle or mood. None of the personality traits were associated with MCI overall or amnestic MCI.

CONCLUSION

These findings provide evidence of a distinct relationship between personality traits and development of specific pre-dementia syndromes. J Am Geriatr Soc 68:1554-1559, 2020.

Neuroticism, conscientiousness, and in vivo Alzheimer pathologies measured by amyloid PET and MRI

AIM

It has been suggested that personality traits, particularly neuroticism and conscientiousness, are risk factors for Alzheimer's disease (AD) and related cognitive decline. However, the underlying pathological links between personality traits and AD-related cognitive impairments remain unclear. Thus, the present study investigated associations of neuroticism and conscientiousness with in vivo cerebral amyloid-beta (Aβ) burden, AD-signature regional neurodegeneration, and white matter hyperintensities (WMH) in non-demented middle- and old-aged adults.

METHODS

A total of 397 non-demented participants underwent comprehensive clinical and neuropsychological assessments, ¹¹ C-labeled Pittsburgh Compound B positron emission tomography, and magnetic resonance imaging. Additionally, the NEO Five-Factor Inventory was administered to both the participants and their informants to measure neuroticism and conscientiousness.

RESULTS

Neither neuroticism nor conscientiousness was associated with cerebral Aβ deposition or WMH. In contrast, higher neuroticism and lower conscientiousness, reported by informants in particular, were significantly associated with reduced AD-signature region cortical thickness. In regards to the direct and indirect effect of each personality on AD-signature region cortical thickness, only the direct effects were found, whereas indirect effects via Aβ deposition or WMH were not.

CONCLUSION

The present findings suggest that amyloid-independent regional neurodegeneration might underlie relations of neuroticism and conscientiousness with AD.

Personality factors and cerebral glucose metabolism in community-dwelling older adults

Personality factors have been associated with Alzheimer's disease (AD) and dementia, but they have not been examined against markers of regional brain glucose metabolism (a primary measure of brain functioning) in older adults without clinically diagnosed cognitive impairment. The relationship between personality factors derived from the five-factor model and cerebral glucose metabolism determined using positron emission tomography (PET) with [18F]-2-fluoro-2-deoxy-D-glucose (18F-FDG-PET) was examined in a cohort of 237 non-demented, community-dwelling older adults aged 60-89 years (M ± SD = 73.76 ± 6.73). Higher neuroticism and lower scores on extraversion and conscientiousness were significantly associated with decreased glucose metabolism in brain regions typically affected by AD neuropathological processes, including the hippocampus and entorhinal cortex. Furthermore, while there were significant differences between apolipoprotein E (APOE) ε4 allele carriers and non-carriers on ¹⁸F-FDG-PET results in the neocortex and other brain regions (p < 0.05), there was no significant difference between carriers and non-carriers on personality factors and no significant interactions were found between APOE ε4 carriage and personality factors on brain glucose metabolism. In conclusion, we found significant relationships between personality factors and glucose metabolism in neural regions more susceptible to AD neuropathology in older adults without clinically significant cognitive impairment. These findings support the need for longitudinal research into the potential mechanisms underlying the relationship between personality and dementia risk, including measurement of change in other AD biomarkers (amyloid and tau imaging) and how they correspond to change in personality factors. Future research is also warranted to determine whether timely psychological interventions aimed at personality facets (specific aspects or characteristics of personality factors) can affect imaging or other biomarkers of AD resulting in delay or ideally preventing the onset of the cognitive impairment.

Vital Exhaustion and Incidence of Dementia: Results from the Copenhagen City Heart Study

BACKGROUND

Psychological distress is potentially linked to the risk of dementia through neurologic and cardiovascular mechanisms. Vital exhaustion (VE) is a mental state of psychological distress, which could be a risk factor for dementia.

OBJECTIVE

To investigate whether VE is a risk factor for dementia in later life.

METHODS

We used data from 6,807 participants attending the third survey of the Copenhagen City Heart Study in 1991-1994. VE was assessed by 17 symptoms (score: 0-17) from the Maastricht Questionnaire. Information on dementia was obtained from national registers. Risk time for dementia was counted from five years after VE assessment for participants > 55 years at the time of VE assessment. For younger participants, risk time for dementia was counted from the year they turned 60 years and onwards. Participants were followed until 2016. We used Poisson regression to calculate incidence rate ratios (IRR) and their 95% confidence intervals (CI).

RESULTS

During an average follow-up of 10 years, 872 participants were registered with dementia. We found a dose-response relation between the number of VE symptoms and the incidence of dementia. For every additional VE symptom, the dementia incidence increased by 2% (IRR = 1.024; 95% CI: 1.004-1.043). Adjustment for socio-demographic and health-related factors did not change the results substantially. Neither did stratification by age, sex, educational level, and marital status.

CONCLUSION

We found evidence that VE is a risk factor for dementia. Our sensitivity analyses supported that this association was not only due to VE being a potential prodromal sign of dementia.

Association Between High School Personality Phenotype and Dementia 54 Years Later in Results From a National US Sample

IMPORTANCE

Personality phenotype has been associated with subsequent dementia in studies of older adults. However, neuropathologic changes often precede cognitive symptoms by many years and may affect personality itself. Therefore, it is unclear whether supposed dementia-prone personality profiles (high neuroticism and low conscientiousness) are true risk factors or merely reflections of preexisting disease.

OBJECTIVES

To examine whether personality during adolescence-a time when preclinical dementia pathology is unlikely to be present-confers risk of dementia in later life and to test whether associations could be accounted for by health factors in adolescence or differed across socioeconomic status (SES).

DESIGN, SETTING, AND PARTICIPANTS

Cohort study in the United States. Participants were members of Project Talent, a national sample of high school students in 1960. Individuals were identified who received a dementia-associated International Classification of Diseases, Ninth Revision (ICD-9) diagnosis code during any year between 2011 and 2013. The dates of our analysis were March 2018 to May 2019.

EXPOSURES

Ten personality traits were measured by the 150-item Project Talent Personality Inventory. Socioeconomic status was measured by a composite based on parental educational level, income, occupation, and property ownership. Participants were also surveyed on demographic factors and height and weight.

MAIN OUTCOMES AND MEASURES

Medicare records were collected, with dementia diagnoses in the period of 2011 to 2013 classified according to the US Centers for Medicare & Medicaid Services ICD-9-based algorithm. Cox proportional hazards regression models estimated the relative risk of dementia based on the 10 personality traits, testing interactions with SES and adjusting for demographic confounders.

RESULTS

The sample of 82 232 participants was 50.1% female, with a mean (SD) age of 15.8 (1.7) years at baseline and 69.5 (1.2) years at follow-up. Lower risk of dementia was associated with higher levels of vigor (hazard ratio for 1 SD, 0.93; 95% CI, 0.90-0.97; P < .001). Calm and maturity showed protective associations with later dementia that increased with SES. At 1 SD of SES, calm showed a hazard ratio of 0.89 (95% CI, 0.84-0.95; P < .001 for the interaction) and maturity showed a hazard ratio of 0.90 (95% CI, 0.85-0.96; P = .001 for the interaction).

CONCLUSIONS AND RELEVANCE

This study's findings suggest that the adolescent personality traits associated with later-life dementia are similar to those observed in studies of older persons. Moreover, the reduction in dementia risk associated with a calm and mature adolescent phenotype may be greater at higher levels of SES. Personality phenotype may be a true independent risk factor for dementia by age 70 years, preceding it by almost 5 decades and interacting with adolescent socioeconomic conditions.

Midlife Forgetfulness and Risk of Dementia in Old Age: Results from the Danish Working Environment Cohort Study

BACKGROUND

Despite the current evidence of a high prevalence of forgetfulness in middle-aged individuals, and the evidence of a link between midlife memory complaints and biological changes in the brain, no previous study has yet investigated midlife forgetfulness in relation to risk of dementia in old age.

AIMS

We investigated whether midlife forgetfulness was an indicator of an increased risk of dementia in old age.

METHODS

We used data from 3,136 employed men and women who participated in the Danish Work Environment Cohort Study in 1990. These data were linked to Danish national registers. Participants were asked whether their closest relative had ever told them that they were forgetful. Incidence rate ratios (IRR) were estimated using Poisson regression analysis.

RESULTS

At baseline, 749 (24%) study participants were categorized as forgetful, and 86 (2.7%) participants were diagnosed with dementia during a total of 31,724 person-years at risk. After adjusting for sociodemographic factors, comorbidities, and work-related factors, midlife forgetfulness was associated with a higher risk of dementia (IRR = 1.82; 95% CI: 1.12-2.97).

CONCLUSIONS

This study is the first to investigate midlife forgetfulness and dementia, and the results suggest that midlife forgetfulness is an early indicator of an increased risk of dementia in old age.

Making DEEP Sense of Lifestyle Risk and Resilience

To effectively promote life-long health and resilience against – for example – neurodegenerative diseases, evidence-based recommendations must acknowledge the complex multidimensionality not only of the diseases but also of personal lifestyle. In a straightforward descriptive and heuristic framework, more than 50 potential lifestyle factors cluster around diet (D), education (E), exercise (E), and purpose (P), unveiling their many relationships across domains and scales. The resulting systematics and its visualization might be a small but helpful step toward the development of more comprehensive, interdisciplinary models of lifestyle-dependent risk and resilience and a means to explain the opportunities and limitations of preventive measures to the public and other stakeholders. Most importantly, this perspective onto the subject implies that not all lifestyle factors are created equal but that there is a hierarchy of values and needs that influences the success of lifestyle-based interventions.

The influence of personality traits and facets on visuo-spatial task performance and self-assessed visuo-spatial inclinations in young and older adults

Aims

Personality traits are suggested to influence adults’ cognitive performance, but little is known about their association with visuo-spatial competence, in terms of those visuo-spatial abilities and inclinations crucial to remaining autonomous, especially with aging. This study newly investigated whether, and to what extent, major traits and narrower facets of personality influence young and older adults’ performance in the so-called objective visuo-spatial abilities (mental rotation and visuo-spatial working memory [VSWM]), and self-assessed visuo-spatial inclinations (pleasure and anxiety in exploring places).

Method

Seventy young adults (18–35 years old) and 70 older adults (65–75 years old) completed the Big-Five questionnaire, objective rotation and VSWM tasks, and spatial self-assessments on pleasure and anxiety in exploring places.

Results

Hierarchical regression models confirmed that age negatively predicted the variance in objective visuo-spatial tasks, but not in self-assessed visuo-spatial inclinations, while only the latter were slightly influenced by gender (in favor of men). Further, both objective visuo-spatial abilities (albeit modestly) and self-assessed visuo-spatial inclinations were predicted by higher Conscientiousness. The latter were also predicted by higher Emotional Stability. Finally, a better objective visuo-spatial performance was explained (again modestly) by lower Dynamism and Politeness, and higher Emotion Control, while higher Perseverance, Emotion Control and Cooperativeness explained a moderate part of the variance in the positive self-assessed visuo-spatial inclinations.

Conclusions

Our findings indicate that, beyond age and gender, some personality traits and facets predict self-assessed visuo-spatial inclinations to a larger extent than objective visuo-spatial performance. These results are discussed within the spatial cognition and aging framework.

Different Cognitive Frailty Models and Health- and Cognitive-related Outcomes in Older Age: From Epidemiology to Prevention

Frailty, a critical intermediate status of the aging process that is at increased risk for negative health-related events, includes physical, cognitive, and psychosocial domains or phenotypes. Cognitive frailty is a condition recently defined by operationalized criteria describing coexisting physical frailty and mild cognitive impairment (MCI), with two proposed subtypes: potentially reversible cognitive frailty (physical frailty/MCI) and reversible cognitive frailty (physical frailty/pre-MCI subjective cognitive decline). In the present article, we reviewed the framework for the definition, different models, and the current epidemiology of cognitive frailty, also describing neurobiological mechanisms, and exploring the possible prevention of the cognitive frailty progression. Several studies suggested a relevant heterogeneity with prevalence estimates ranging 1.0–22.0% (10.7–22.0% in clinical-based settings and 1.0–4.4% in population-based settings). Cross-sectional and longitudinal population-based studies showed that different cognitive frailty models may be associated with increased risk of functional disability, worsened quality of life, hospitalization, mortality, incidence of dementia, vascular dementia, and neurocognitive disorders. The operationalization of clinical constructs based on cognitive impairment related to physical causes (physical frailty, motor function decline, or other physical factors) appears to be interesting for dementia secondary prevention given the increased risk for progression to dementia of these clinical entities. Multidomain interventions have the potential to be effective in preventing cognitive frailty. In the near future, we need to establish more reliable clinical and research criteria, using different operational definitions for frailty and cognitive impairment, and useful clinical, biological, and imaging markers to implement intervention programs targeted to improve frailty, so preventing also late-life cognitive disorders.

Negative Affect Is Associated With Higher Risk of Incident Cognitive Impairment in Nondepressed Postmenopausal Women

Background

Positive affect (PA) and negative affect (NA) reflect subjective emotional experiences. Although related to depression and anxiety, these dimensions are distinct constructs representing affective states and patterns. Prior studies suggest that elevated depressive symptoms are associated with risk of mild cognitive impairment (MCI) and probable dementia, but whether affective states are associated with cognitive impairment is still unknown. The present study examined relationships between baseline affective states and cognitive impairment (MCI, probable dementia) in nondepressed women.

Method

Baseline PA and NA were assessed in postmenopausal women (N = 2,137; mean age = 73.8 years) from the Women's Health Initiative Study of Cognitive Aging (WHISCA) using the Positive and Negative Affect Schedule (PANAS). Women were followed annually for an average of 11.3 years; those with elevated depressive symptoms at baseline were excluded.

Results

Higher NA was associated with a higher risk of MCI and probable dementia, even after adjusting for important covariates including age, education, sociodemographic, lifestyle, and cardiovascular risk factors, global cognition, and hormone therapy assignment at baseline. PA was not significantly associated with either outcome.

Conclusions

We present the first evidence to date that greater NA, even in the absence of elevated depressive symptoms, is associated with higher risk of MCI and dementia. This suggests that NA may be an important, measureable and potentially modifiable risk factor for age-related cognitive decline.

Health-Promoting Strategies for the Aging Brain

As the world's population ages and people live longer, the changes in the aging brain present substantial challenges to our health and society. With greater longevity come age-related diseases, many of which have direct and indirect influences on the health of the brain. Although there is some degree of predictable decline in brain functioning with aging, meaningful cognitive decline is not inevitable and is perhaps preventable. In this review, we present the case that the course of aging-related brain disease and dysfunction can be modified. We present the evidence for conditions and risk factors that may contribute to cognitive decline and dementia and for interventions that may mitigate their impact on cognitive functioning later in life, or even prevent them and their cognitive sequelae from developing. Although much work remains to be done to meet the challenges of the aging brain, strategies to promote its health have been demonstrated and offer much promise, which can only be realized if we mount a vigorous public health effort to implement these strategies.

Genetic basis of motoric cognitive risk syndrome in the Health and Retirement Study

OBJECTIVE

To examine polygenic inheritance of motoric cognitive risk syndrome (MCR), a predementia syndrome characterized by the presence of subjective cognitive complaints and slow gait.

METHODS

We analyzed 4,915 individuals, age 65 years and above, with European ancestry (mean age 75.0 ± 6.8 years, 56.6% women) in the Health and Retirement Study. Polygenic scores (PGS) were calculated as weighted sums of the effect of single nucleotide polymorphisms, with effect sizes derived from genome-wide association studies. The association between PGSs of 9 phenotypes (general cognition, body mass index [BMI], mean arterial pressure, education, Alzheimer disease [AD], neuroticism, well-being, waist circumference, and depressive symptoms) and MCR as well as its key components (cognitive complaints and slow gait) were examined by logistic regression, adjusting for age, sex, education, and genetic ancestry, and reported as odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

There were 260 prevalent MCR cases, 529 with slow gait, and 1,928 with subjective cognitive complaints. Higher PGSs for BMI (OR 1.22, 95% CI 1.07-1.39) and waist circumference (OR 1.23, 95% CI 1.07-1.40) were associated with MCR, and PGS of AD showed a suggestive association (OR 1.16, 95% CI 1.02-1.32). Higher PGS for neuroticism (OR 1.10, 95% CI 1.03-1.18) was associated with cognitive complaints, whereas higher well-being PGS (OR 0.92, 95% CI 0.87-0.98) was protective. PGS for BMI (OR 1.16, 95% CI 1.06-1.28), waist circumference (OR 1.19, 95% CI 1.08-1.31), and AD (OR 1.13, 95% CI 1.03-1.24) was associated with slow gait.

CONCLUSION

Obesity-related genetic traits increase risk of MCR syndrome; further investigation is required to identify potential therapeutic targets.

Prolonged or serious conflicts at work and incident dementia: a 23-year follow-up of the Copenhagen City Heart Study

PURPOSE

Only a few studies have investigated the impact of negative aspects of social relations on cognitive function, and they have shown mixed results. Conflicts at work are part of the negative aspects of social relations, but the impact of experiencing conflicts at work has not yet been investigated as a risk factor for dementia. Therefore, we investigated whether experiencing prolonged or serious conflicts with a supervisor or colleagues at work was associated with incident dementia in old age.

METHODS

We analyzed data of 6,436 men and women from the third survey of the Copenhagen City Heart Study. At baseline in 1991-1994, the participants reported whether they had ever had a prolonged or serious conflict at work. The participants were followed until 2014. We used Poisson regression to estimate incidence rate ratios (IRR) and their 95% confidence intervals (CI).

RESULTS

After adjusting for potential confounders, the IRR for dementia was 1.53 (95% CI 0.77-3.03) among participants who had reported having prolonged or serious conflicts both with a supervisor and colleagues compared with participants who had never had such conflicts. In separate analyses stratified by sex, the IRRs were 2.14 (95% Cl 0.97-4.71) for men and 0.98 (95% Cl 0.29-3.32) for women.

CONCLUSIONS

Our findings did not support an overall association between experiencing prolonged or serious conflicts at work and incident dementia. However, because of the large differences in the point estimates for men and women, future research could aim at investigating potential sex differences regarding the association between conflicts at work and dementia.