Do We Become More Lonely With Age? A Coordinated Data Analysis of Nine Longitudinal Studies.

Loneliness is a pervasive experience with adverse impacts on health and well-being. Despite its significance, notable gaps impede a full understanding of how loneliness changes across the adult life span and what factors influence these changes. To address this, we conducted a coordinated data analysis of nine longitudinal studies encompassing 128,118 participants ages 13 to 103 from over 20 countries. Using harmonized variables and models, we examined loneliness trajectories and predictors. Analyses revealed that loneliness follows a U-shaped curve, decreasing from young adulthood to midlife and increasing in older adulthood. These patterns were consistent across studies. Several baseline factors (i.e., sex, marital status, physical function, education) were linked to loneliness levels, but few moderated the loneliness trajectories. These findings highlight the dynamic nature of loneliness and underscore the need for targeted interventions to reduce social disparities throughout adulthood.

Personality predictors of dementia diagnosis and neuropathological burden: An individual participant data meta-analysis.

INTRODUCTION: The extent to which the Big Five personality traits and subjective well-being (SWB) are discriminatory predictors of clinical manifestation of dementia versus dementia-related neuropathology is unclear. METHODS: Using data from eight independent studies (Ntotal = 44,531; Ndementia = 1703; baseline Mage = 49 to 81 years, 26 to 61% female; Mfollow-up range = 3.53 to 21.00 years), Bayesian multilevel models tested whether personality traits and SWB differentially predicted neuropsychological and neuropathological characteristics of dementia. RESULTS: Synthesized and individual study results indicate that high neuroticism and negative affect and low conscientiousness, extraversion, and positive affect were associated with increased risk of long-term dementia diagnosis. There were no consistent associations with neuropathology. DISCUSSION: This multistudy project provides robust, conceptually replicated and extended evidence that psychosocial factors are strong predictors of dementia diagnosis but not consistently associated with neuropathology at autopsy. HIGHLIGHTS: N(+), C(-), E(-), PA(-), and NA(+) were associated with incident diagnosis. Results were consistent despite self-report versus clinical diagnosis of dementia. Psychological factors were not associated with neuropathology at autopsy. Individuals with higher conscientiousness and no diagnosis had less neuropathology. High C individuals may withstand neuropathology for longer before death.

Associations Between Generativity and Social Asymmetry Among Older Adults in Japan.

OBJECTIVES: Loneliness and social isolation are major public health concerns among older adults in Japan. Generativity, the concern for and commitment to future generations, may buffer older adults from loneliness. This study examined the cross-sectional and longitudinal associations between generativity and social asymmetry (the discrepancy between social isolation and loneliness) among older adults in Japan. METHODS: Data were from 2 waves (2008 and 2012) of the Midlife in Japan survey, a nationally representative longitudinal study of 645 adults aged 30-79 residing in the Tokyo metropolitan area. Generativity was measured using the 6-item Loyola Generativity Scale. Social asymmetry was computed as the residual score from regressing loneliness onto social isolation. RESULTS: Higher generativity levels were associated with lower social asymmetry scores (B=-0.21, SE=0.04), but generativity change across waves did not predict social asymmetry 4 years later (B=-0.04, SE=0.06). DISCUSSION: Generativity may play a protective role in buffering older adults from the adverse effects of social isolation on loneliness. Promoting generativity among older adults may be a potential intervention strategy to reduce loneliness and improve well-being in aging populations in Japan.

Availability of Cognitive Resources in Early Life Predicts Transitions Between Cognitive States in Middle and Older Adults From Europe.

Background and Objectives: The existing literature highlights the importance of reading books in middle-to-older adulthood for cognitive functioning; very few studies, however, have examined the importance of childhood cognitive resources for cognitive outcomes later in life. Research Design and Methods: Using data from 11 countries included in the Survey of Health, Ageing, and Retirement in Europe (SHARE) data set (N = 32,783), multistate survival models (MSMs) were fit to examine the importance of access to reading material in childhood on transitions through cognitive status categories (no cognitive impairment and impaired cognitive functioning) and death. Additionally, using the transition probabilities estimated by the MSMs, we estimated the remaining years of life without cognitive impairment and total longevity. All models were fit individually in each country, as well as within the pooled SHARE sample. Results: Adjusting for age, sex, education, and childhood socioeconomic status, the overall pooled estimate indicated that access to more books at age 10 was associated with a decreased risk of developing cognitive impairment (adjusted hazard ratio = 0.79, confidence interval: 0.76-0.82). Access to childhood books was not associated with risk of transitioning from normal cognitive functioning to death, or from cognitive impairment to death. Total longevity was similar between participants reporting high (+1 standard deviation [SD]) and low (-1 SD) number of books in the childhood home; however, individuals with more access to childhood books lived a greater proportion of this time without cognitive impairment. Discussion and Implications: Findings suggest that access to cognitive resources in childhood is protective for cognitive aging processes in older adulthood.

The Big Five personality traits and allostatic load in middle to older adulthood: A systematic review and meta-analysis.

Further understanding of the associations between personality traits and allostatic load (AL) may be important for predicting, addressing, and optimizing health outcomes. This review synthesized the existing literature reporting the association between the Big Five personality traits and AL in adults to identify the generalizability and robustness of relationships, potential mechanisms underlying the associations, and study characteristics that may be contributing to inconsistencies in the field. Published and unpublished empirical reports were included if at least one of the Big Five traits was examined and an AL index was constructed using at least two biomarkers in a sample of adults. The methodological plan and standardized coding guide were pre-registered and reported (https://osf.io/rxw5a). Based on 11 studies that met eligibility, meta-analysis of correlation coefficients indicated a small but significant positive association between neuroticism and AL, and small but significant inverse associations between both conscientiousness and openness with AL. This review identifies strengths and limitations within the field, as well as several avenues for future research.

Transitions Between Mild Cognitive Impairment, Dementia, and Mortality: The Importance of Olfaction.

BACKGROUND: The existing literature suggests that impaired olfaction may be an early marker for cognitive decline. Tracking the earliest stages of the progression to dementia is paramount, and yet the importance of olfactory ability throughout cognitive states and death remains unclear. METHODS: Drawing data from the Rush Memory and Aging Project (N = 1 501; 74% female), olfactory ability was assessed using the Brief Smell Identification Test (range = 0-16), while cognitive states (unimpaired, mild cognitive impairment [MCI], and dementia) were determined using a 3-step neuropsychological diagnostic protocol at up to 15 annual occasions. Multistate survival models simultaneously estimated the association of olfactory ability on transitions through cognitive states and death, while multinomial regression models estimated cognitively unimpaired and total life expectancies. RESULTS: Higher olfactory scores were associated with a reduced risk of transitioning from unimpaired cognition to MCI (hazard ratio [HR] = 0.86, 95% confidence interval [CI] = 0.82-0.88) and from MCI to dementia (HR = 0.89, 95% CI = 0.86-0.93), indicating that 1-unit increase in olfactory scores was associated with an approximate 14% and 11% reduction in risk, respectively. Additionally, higher olfactory scores were associated with a greater likelihood of transitioning backward from MCI to unimpaired cognition (HR = 1.07, 95% CI = 1.02-1.12). Furthermore, higher baseline olfactory scores were associated with more years of longevity without cognitive impairment. However, olfaction was not associated with the transition to death when accounting for transitions through cognitive states. CONCLUSIONS: Findings suggest that higher olfactory identification scores are associated with a decreased risk of transitioning to impaired cognitive states and that associations between olfaction and mortality may occur primarily through the pathway of neurodegeneration.

Personality traits, cognitive states, and mortality in older adulthood.

Research suggests that personality traits are associated with mild cognitive impairment (MCI), dementia, and mortality risk, but the timing of when traits are most important in the progression to dementia and the extent to which they are associated with years of cognitive health span are unclear. This project applied secondary data analysis to the Rush Memory and Aging Project (N = 1954; baseline Mage = 80 years; 74% female) over up to 23 annual assessments. Multistate survival modeling examined the extent to which conscientiousness, neuroticism, and extraversion, assessed using the NEO Five Factor Inventory, were associated with transitions between cognitive status categories and death. Additionally, multinomial regression models estimated cognitive health span and total survival based on standard deviation units of personality traits. Adjusting for demographics, depressive symptoms, and apolipoprotein (APOE) ε4, personality traits were most important in the transition from no cognitive impairment (NCI) to MCI. For instance, higher conscientiousness was associated with a decreased risk of transitioning from NCI to MCI, hazard ratio (HR) = 0.78, 95% CI [0.72, 0.85] and higher neuroticism was associated with an increased risk of transitioning from NCI to MCI, HR = 1.12, 95% CI [1.04, 1.21]. Additional significant and nonsignificant results are discussed in the context of the existing literature. While personality traits were not associated with total longevity, individuals higher in conscientiousness and extraversion, and lower in neuroticism, had more years of cognitive health span, particularly female participants. These findings provide novel understanding of the simultaneous associations between personality traits and transitions between cognitive status categories and death, as well as cognitive health span and total longevity. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Personality predictors of cognitive dispersion: A coordinated analysis of data from seven international studies of older adults.

OBJECTIVES: Dispersion in cognitive test performance within a single testing session is proposed as an early marker of poor brain health. Existing research, however, has not investigated factors that may explain individual differences in cognitive dispersion. We investigate the extent to which the Big Five personality traits are associated with cognitive dispersion in older adulthood. METHOD: To promote transparency and reliability, we applied preregistration and conceptual replication via coordinated analysis. Drawing data from seven longitudinal studies of aging (Ntotal = 33,581; Mage range = 56.4-71.2), cognitive dispersion scores were derived from cognitive test results. Independent linear regression models were fit in each study to examine personality traits as predictors of dispersion scores, adjusting for mean cognitive performance and sociodemographics (age, sex, education). Results from individual studies were synthesized using random effects meta-analyses. RESULTS: Synthesized results revealed that openness was positively associated with cognitive dispersion, 0.028, 95% CI [0.003, 0.054]. There was minimal evidence for associations between cognitive dispersion and the other personality traits in independent analyses or meta-analyses. Mean cognitive scores were negatively associated with cognitive dispersion across the majority of studies, while sociodemographic variables were not consistently associated with cognitive dispersion. CONCLUSION: Higher levels of openness were associated with greater cognitive dispersion across seven independent samples, indicating that individuals higher in openness had more dispersion across cognitive tests. Further research is needed to investigate mechanisms that may help to explain the link between openness and cognitive dispersion, as well as to identify additional individual factors, beyond personality traits, that may be associated with cognitive dispersion. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Within-Couple Personality Concordance Over Time: The Importance of Personality Synchrony for Perceived Spousal Support.

OBJECTIVES: Within-couple similarities in personality traits tend to be positively associated with relationship well-being. However, research in this area is typically based on cross-sectional designs, thereby limiting examination of longitudinal personality concordance. Given that life experiences shape within-person change in personality, and that partners within a couple often experience similar life events, investigation of within-couple personality synchrony and associations with marital outcomes is warranted. METHODS: Using data from 3,988 couples (mean age at baseline = 67.0 years, SD = 9.6), multilevel dyadic growth models estimated within-couple similarity in baseline levels, change, and occasion-to-occasion variability for each of the Big Five personality traits over an 8-year follow-up. Bivariate growth models examined the effect of within-couple similarity on perceived spousal support, accounting for dependency within couples. RESULTS: Adjusting for baseline age, education, functional ability, and relationship length, analyses revealed within-couple concordance between baseline levels of all 5 personality traits, as well as correlated within-couple fluctuations in neuroticism, extraversion, and openness over time. Similarity in openness, agreeableness, and neuroticism trajectories predicted spousal support. Couples were most similar in openness, showing correlated intercepts, change, and variability, and this longitudinal synchrony was particularly important for perceived spousal support in women. DISCUSSION: These findings provide evidence for longitudinal personality synchrony over time within older adult couples. Further, concordance in neuroticism, extraversion, and openness predicted perceived spousal support, though there may be some gender differences in personality dynamics and relationship well-being. Effects of similarity were relatively small compared to actor and partner effects of these traits.

The Importance of Engaging in Physical Activity in Older Adulthood for Transitions Between Cognitive Status Categories and Death: A Coordinated Analysis of 14 Longitudinal Studies.

BACKGROUND: Given increasing incidence of cognitive impairment and dementia, further understanding of modifiable factors contributing to increased healthspan is crucial. Extensive literature provides evidence that physical activity (PA) delays the onset of cognitive impairment; however, it is unclear whether engaging in PA in older adulthood is sufficient to influence progression through cognitive status categories. METHOD: Applying a coordinated analysis approach, this project independently analyzed 14 longitudinal studies (NTotal = 52 039; mean baseline age across studies = 69.9-81.73) from North America and Europe using multistate survival models to estimate the impact of engaging in PA on cognitive status transitions (nonimpaired, mildly impaired, severely impaired) and death. Multinomial regression models were fit to estimate life expectancy (LE) based on American PA recommendations. Meta-analyses provided the pooled effect sizes for the role of PA on each transition and estimated LEs. RESULTS: Controlling for baseline age, sex, education, and chronic conditions, analyses revealed that more PA is significantly associated with decreased risk of transitioning from nonimpaired to mildly impaired cognitive functioning and death, as well as substantially longer LE. Results also provided evidence for a protective effect of PA after onset of cognitive impairment (eg, decreased risk of transitioning from mild-to-severe cognitive impairment; increased likelihood of transitioning backward from severe-to-mild cognitive impairment), though between-study heterogeneity suggests a less robust association. CONCLUSIONS: These results yield evidence for the importance of engaging in PA in older adulthood for cognitive health, and a rationale for motivating older adults to engage consistently in PA.

Is Healthy Neuroticism Associated with Health Behaviors? A Coordinated Integrative Data Analysis.

Current literature suggests that neuroticism is positively associated with maladaptive life choices, likelihood of disease, and mortality. However, recent research has identified circumstances under which neuroticism is associated with positive outcomes. The current project examined whether "healthy neuroticism", defined as the interaction of neuroticism and conscientiousness, was associated with the following health behaviors: smoking, alcohol consumption, and physical activity. Using a pre-registered multi-study coordinated integrative data analysis (IDA) approach, we investigated whether "healthy neuroticism" predicted the odds of engaging in each of the aforementioned activities. Each study estimated identical models, using the same covariates and data transformations, enabling optimal comparability of results. These results were then meta-analyzed in order to estimate an average (N-weighted) effect and to ascertain the extent of heterogeneity in the effects. Overall, these results suggest that neuroticism alone was not related to health behaviors, while individuals higher in conscientiousness were less likely to be smokers or drinkers, and more likely to engage in physical activity. In terms of the healthy neuroticism interaction of neuroticism and conscientiousness, significant interactions for smoking and physical activity suggest that the association between neuroticism and health behaviors was smaller among those high in conscientiousness. These findings lend credence to the idea that healthy neuroticism may be linked to certain health behaviors and that these effects are generalizable across several heterogeneous samples.

Is Healthy Neuroticism Associated with Chronic Conditions? A Coordinated Integrative Data Analysis.

Early investigations of the neuroticism by conscientiousness interaction with regards to health have been promising, but to date, there have been no systematic investigations of this interaction that account for the various personality measurement instruments, varying populations, or aspects of health. The current study - the second of three - uses a coordinated analysis approach to test the impact of the neuroticism by conscientiousness interaction on the prevalence and incidence of chronic conditions. Using 15 pre-existing longitudinal studies (N > 49,375), we found that conscientiousness did not moderate the relationship between neuroticism and having hypertension (OR = 1.00,95%CI[0.98,1.02]), diabetes (OR = 1.02[0.99,1.04]), or heart disease (OR = 0.99[0.97,1.01]). Similarly, we found that conscientiousness did not moderate the prospective relationship between neuroticism and onset of hypertension (OR = 0.98,[0.95,1.01]), diabetes (OR = 0.99[0.94,1.05]), or heart disease (OR = 0.98[0.94,1.03]). Heterogeneity of effect sizes was largely nonsignificant, with one exception, indicating that the effects are consistent between datasets. Overall, we conclude that there is no evidence that healthy neuroticism, operationalized as the conscientiousness by neuroticism interaction, buffers against chronic conditions.

Trajectories of Big Five Personality Traits: A Coordinated Analysis of 16 Longitudinal Samples.

This study assessed change in self-reported Big Five personality traits. We conducted a coordinated integrative data analysis using data from 16 longitudinal samples, comprising a total sample of over 60 000 participants. We coordinated models across multiple datasets and fit identical multi-level growth models to assess and compare the extent of trait change over time. Quadratic change was assessed in a subset of samples with four or more measurement occasions. Across studies, the linear trajectory models revealed declines in conscientiousness, extraversion, and openness. Non-linear models suggested late-life increases in neuroticism. Meta-analytic summaries indicated that the fixed effects of personality change are somewhat heterogeneous and that the variability in trait change is partially explained by sample age, country of origin, and personality measurement method. We also found mixed evidence for predictors of change, specifically for sex and baseline age. This study demonstrates the importance of coordinated conceptual replications for accelerating the accumulation of robust and reliable findings in the lifespan developmental psychological sciences.

Increases in Neuroticism May Be an Early Indicator of Dementia: A Coordinated Analysis.

OBJECTIVES: Although personality change is typically considered a symptom of dementia, some studies suggest that personality change may be an early indication of dementia. One prospective study found increases in neuroticism preceding dementia diagnosis (Yoneda, T., Rush, J., Berg, A. I., Johansson, B., & Piccinin, A. M. (2017). Trajectories of personality traits preceding dementia diagnosis. The Journals of Gerontology. Series B, Psychological Sciences and Social Sciences, 72, 922-931. doi:10.1093/geronb/gbw006). This study extends this research by examining trajectories of personality traits in additional longitudinal studies of aging. METHODS: Three independent series of latent growth curve models were fitted to data from the Longitudinal Aging Study Amsterdam and Einstein Aging Study to estimate trajectories of personality traits in individuals with incident dementia diagnosis (total N = 210), in individuals with incident Mild Cognitive Impairment (N = 135), and in individuals who did not receive a diagnosis during follow-up periods (total N = 1740). RESULTS: Controlling for sex, age, education, depressive symptoms, and the interaction between age and education, growth curve analyses consistently revealed significant linear increases in neuroticism preceding dementia diagnosis in both datasets and in individuals with mild cognitive impairment. Analyses examining individuals without a diagnosis revealed nonsignificant change in neuroticism overtime. DISCUSSION: Replication of our previous work in 2 additional datasets provides compelling evidence that increases in neuroticism may be early indication of dementia, which can facilitate development of screening assessments.

Is there a positive side to sensation seeking? Trajectories of sensation seeking and impulsivity may have unique outcomes in young adulthood.

INTRODUCTION: High levels of sensation seeking and impulsivity in adolescence are typically associated with risky behaviours; limited research has examined the relation of these traits to positive outcomes. Given that adolescence is a sensitive developmental period that can impact success later in life, we adopt the Positive Youth Development Framework to better understand how the development of self-reported sensation seeking and impulsivity may be differentially related to positive markers of early adulthood. METHOD: Data are from the Victoria Healthy Youth Survey (T1 N = 662; 52% female), a six-wave longitudinal cohort study of Canadian youth. Parallel process latent class growth analysis estimated trajectories of sensation seeking and impulsivity identifying classes of youth (ages 14-28). Controlling for baseline age, sex, and socio-economic status, linear regression analyses examined how longitudinal patterns (classes) of sensation seeking and impulsivity were related to positive markers of early adulthood. RESULTS: Three classes of youth were identified. These varied in levels and trajectories of change in sensation seeking (Ss) and impulsivity (I): LowSs-LowI, 26%; HighSs-HighI, 35%; ModerateSs-LowI, 38%. In young adulthood (T6; ages 22-29), youth in the LowSs-LowI and ModerateSs-LowI classes had significantly higher educational and occupational achievement, and lower financial strain, compared to youth in the HighSs-HighI class. Further, the ModerateSs-LowI class was associated with the highest levels of income and well-being. CONCLUSIONS: Findings identified differential trajectories of sensation seeking and impulsivity, with youth in the ModerateSs-LowI class, followed by the LowSs-LowI class, reporting the most positive outcomes in young adulthood.

Personality Predicts Mortality Risk: An Integrative Data Analysis of 15 International Longitudinal Studies.

This study examined the Big Five personality traits as predictors of mortality risk, and smoking as a mediator of that association. Replication was built into the fabric of our design: we used a Coordinated Analysis with 15 international datasets, representing 44,094 participants. We found that high neuroticism and low conscientiousness, extraversion, and agreeableness were consistent predictors of mortality across studies. Smoking had a small mediating effect for neuroticism. Country and baseline age explained variation in effects: studies with older baseline age showed a pattern of protective effects (HR<1.00) for openness, and U.S. studies showed a pattern of protective effects for extraversion. This study demonstrated coordinated analysis as a powerful approach to enhance replicability and reproducibility, especially for aging-related longitudinal research.

Trajectories of Personality Traits Preceding Dementia Diagnosis.

BACKGROUND: Several retrospective studies using informant report have shown that individuals with dementia demonstrate considerable personality change. Two prospective studies, also using informant report, have shown that individuals who develop dementia show some personality changes prior to diagnosis. The current study is the first to assess personality trait change prior to dementia diagnosis using self-report measures from longitudinal data. METHOD: This study used data from the Swedish OCTO-Twin Study, a longitudinal panel of 702 twins aged 80 and older. Analysis was restricted to 86 individuals who completed the Eysenck Personality Inventory and received a dementia diagnosis during follow-up occasions. Latent growth curve analyses were used to examine trajectories of extraversion and neuroticism preceding dementia diagnosis. RESULTS: Controlling for sex, age, education, depressive symptoms, and the interaction between age and education, growth curve analyses revealed a linear increase in neuroticism and stability in extraversion. Individuals who were eventually diagnosed with dementia showed a significant increase in neuroticism preceding diagnosis of dementia. DISCUSSION: Personality change, specifically an increase in neuroticism, may be an early indicator of dementia. Identification of early indicators of dementia may facilitate development of screening assessments and aid in early care strategies and planning.