Personality and Transition From Mild Cognitive Impairment to Normal Cognition vs Dementia.

OBJECTIVES: Mild cognitive impairment (MCI) is a critical stage preceding incident dementia, but not all individuals with MCI progress to dementia and some revert to normal cognition. This study examined whether personality is associated with the probability of transition from MCI to normal cognition or dementia. DESIGN: Longitudinal observational study. SETTING AND PARTICIPANTS: Older adults with MCI from the Health and Retirement Study (N = 1608, 56% female, mean age = 72.29, SD = 9.91). Personality traits; cognitive status; and demographic (age, sex, education, race, and ethnicity), clinical (diabetes, hypertension), behavioral (smoking, physical activity), psychological (depressive symptoms), and genetic (apolipoprotein E ε4) covariates were obtained in 2006/2008. Follow-up data on cognitive status were collected every 2 years up to the 2020 wave. METHODS: Cox regression analyses tested the association between personality and reversion from MCI to normal cognition and progression to dementia, controlling for demographic, clinical, behavioral, psychological, and genetic covariates. RESULTS: Controlling for demographic factors, lower neuroticism and higher openness and conscientiousness were associated with a higher likelihood of reversion from MCI to normal cognition and a lower risk of progression to dementia over time. Higher agreeableness was related to a lower risk of progression to dementia. Clinical, behavioral, psychological, and genetic factors partially accounted for these associations. There was little evidence that demographic, genetic factors, or baseline cognition moderated these associations. CONCLUSIONS AND IMPLICATIONS: Personality traits can help identify individuals who are more likely to revert from MCI and not progress to dementia. These findings suggest that even during mild impairment, personality may modulate dementia risk and thus inform targeted interventions.

Balance, Strength, and Risk of Dementia: Findings From the Health and Retirement Study and the English Longitudinal Study of Ageing.

BACKGROUND: Slow gait speed has been consistently associated with an increased risk of dementia. This study examined whether measures of balance and lower limb strength are similarly related to the risk of developing dementia. METHODS: Participants from the Health and Retirement Study (HRS, N = 5 658, mean age = 73.23, standard deviation [SD] = 6.22) and the English Longitudinal Study of Ageing (ELSA, N = 3667, mean age = 69.90, SD = 7.02) completed measures of gait speed, semi-tandem balance, chair stand (ELSA only), and cognitive status at baseline. Cognitive status was assessed over up to 15 years. RESULTS: Baseline slower gait speed (hazard ratio [HR]HRS = 1.52, 95% confidence interval [CI] = 1.32-1.75, p < .001; HRELSA = 1.73, 95% CI = 1.37-2.18, p < .001); and balance impairment (HRHRS = 1.58, 95% CI = 1.26-1.96, p < .001; HRELSA = 1.97, 95% CI = 1.24-3.14, p < .01) were related to a higher risk of incident dementia, adjusting for demographic factors. The combination of slower gait and impaired balance was associated with a two-to-three times higher risk of dementia in HRS and ELSA. Worse performance on the chair stand at baseline was associated with a higher risk of dementia in ELSA (HR = 1.56, 95% CI = 1.23-1.99, p < .001). All performance measures remained significant when entered simultaneously and accounted for obesity, diabetes, blood pressure, physical activity, smoking, and depressive symptoms. There was little evidence that age, sex, or APOE ε4 moderated the association. CONCLUSIONS: Similar to gait speed, measures of balance and strength are associated with a higher risk of incident dementia. The findings have implications for clinical practice, given that these routinely used geriatric assessment tools are similarly related to dementia risk.

Personality and Cognition: The Mediating Role of Inflammatory Markers.

OBJECTIVES: Five-Factor Model personality traits are associated consistently with cognition. Inflammation has been hypothesized as a biological pathway in this association, but this assumption has yet to be tested. The present study tested inflammatory markers as mediators between personality traits and cognition. METHODS: Participants were from the Health and Retirement Study (HRS; N = 4,364; 60% women; mean age = 64.48 years, standard deviation = 8.79). Personality traits and demographic factors were assessed in 2010/2012. Data on inflammatory markers (high-sensitivity C-reactive protein [hsCRP], interleukin-6 [IL-6], soluble tumor necrosis factor 1 (sTNFR1), interleukin-10 [IL-10], interleukin-1 receptor antagonist [IL-1Ra], and transforming growth factor [TGF]-ß1) were obtained in 2016 from the HRS Venuous Blood Study. Cognition was assessed in 2020 using the modified Telephone Interview for Cognitive Status. RESULTS: Higher neuroticism was related to lower cognition at follow-up, whereas higher extraversion, openness, agreeableness, and conscientiousness were associated with better cognition. Higher extraversion and higher conscientiousness were related to lower hsCRP, IL-6, IL-10, IL-1Ra, and sTNFR1, and higher openness was associated with lower IL-10, IL-1Ra, and sTNFR1 and to higher soluble TGF-ß1. Lower sTNFR1 partially mediated the associations between conscientiousness, extraversion, and openness and cognition at follow-up, explaining an estimated 4%-12% of these associations. The mediating role of sTNFR1 persisted when physical activity and depressive symptoms were included as additional mediators. DISCUSSION: The present study provides new evidence on personality and inflammatory markers. Consistent with the inflammation hypothesis, the sTNFR1 finding supports a potential biological pathway between personality and cognition.

Personality and Risk of Incident Stroke in 6 Prospective Studies.

BACKGROUND: A large literature has examined a broad range of factors associated with increased risk of stroke. Few studies, however, have examined the association between personality and stroke. The present study adopted a systematic approach using a multi-cohort design to examine the associations between 5-Factor Model personality traits (neuroticism, extraversion, openness, agreeableness, and conscientiousness) and incident stroke using data from 6 large longitudinal samples of adults. METHODS: Participants (age range: 16-104 years old, N=58 105) were from the MIDUS (Midlife in the United States) Study, the HRS (Health and Retirement Study), The US (Understanding Society) study, the WLS (Wisconsin Longitudinal Study), the NHATS (National Health and Aging Trends Study), and the LISS (Longitudinal Internet Studies for the Social Sciences). Personality traits, demographic factors, clinical and behavioral risk factors were assessed at baseline; stroke incidence was tracked over 7 to 20 years follow-up. RESULTS: Meta-analyses indicated that higher neuroticism was related to a higher risk of incident stroke (hazard ratio, 1.15 [95% CI, 1.10-1.20]; P<0.001), whereas higher conscientiousness was protective (HR, 0.89 [95% CI, 0.85-0.93]; P<0.001). Additional meta-analyses indicated that BMI, diabetes, blood pressure, physical inactivity, and smoking as additional covariates partially accounted for these associations. Extraversion, openness, and agreeableness were unrelated to stroke incidence. CONCLUSIONS: Similar to other cardiovascular and neurological conditions, higher neuroticism is a risk factor for stroke incidence, whereas higher conscientiousness is a protective factor.

Personality and aging-related immune phenotype.

An aging-related immune phenotype (ARIP) has been defined as a decrease in naïve T cells (TN) relative to the accumulation of memory T cells (TM). Recent research implicates ARIP measures, such as CD4 +TN/TM and CD8 +TN/TM ratios, in multimorbidity and mortality. This study examined whether psychological dispositions that assess how people think, feel, and behave are related to CD4 +TN/TM and CD8 +TN/TM. Participants were adults aged 50-104 years (N = 4798; 58% women, Mean Age= 67.95, SD= 9.56) from the Health and Retirement Study. Data on CD4 +TN/TM and CD8 +TN/TM were obtained in 2016. Data on personality, demographic factors, and potential clinical (body mass index, disease burden), behavioral (smoking, alcohol, physical activity), psychological (depressive symptoms, stress), and biological (cytomegalovirus IgG antibodies) mediating factors were obtained in 2014/2016. Controlling for demographic factors, higher conscientiousness was related to higher CD4 +TN/TM and CD8 +TN/TM. To a lesser extent, higher neuroticism and lower extraversion were associated with lower CD4 +TN/TM. Physical activity, and to a lesser extent BMI and disease burden, were the most robust mediators between personality and ARIP measures. Cytomegalovirus IgG level mediated the association between conscientiousness and both CD4 +TN/TM and CD8 +TN/TM. This study provides novel evidence that personality is related to ARIP. Higher conscientiousness and, to a lesser extent, higher extraversion may be protective against age-related immunophenotype change, whereas neuroticism may be a risk factor.

Personality associations with lung function and dyspnea: Evidence from six studies.

OBJECTIVE: The present study examined the association between Five Factor Model personality traits and lung function and dyspnea. METHODS: Participants were middle aged and older adults aged 34-103 years old (N > 25,000) from the Midlife in the United States Study (MIDUS), the Health and Retirement Study (HRS), the English Longitudinal Study of Ageing (ELSA), the National Health and Aging Trends Survey (NHATS), and the Wisconsin Longitudinal Study graduate (WLSG) and sibling (WLSS) samples. Data on peak expiratory flow (PEF), dyspnea, personality traits, smoking, physical activity, body mass index (BMI), emotional/psychiatric problems, and demographic factors were obtained in each sample. RESULTS: A meta-analysis indicated that higher neuroticism was related to lower PEF, higher risk of PEF less than 80% of predicted value, and higher risk of dyspnea. In contrast, higher extraversion and conscientiousness were associated with higher PEF, lower likelihood of PEF lower than 80% of the predicted value, and lower risk of dyspnea. Higher openness was related to higher PEF and lower risk of PEF less than 80%, whereas agreeableness was related to higher PEF and lower risk of dyspnea. Smoking, physical activity, BMI and emotional/psychiatric problems partially accounted for these associations. There was little evidence that lung disease moderated the association between personality and PEF and dyspnea. CONCLUSIONS: Across cohorts, this study found replicable evidence that personality is associated with lung function and associated symptomatology.

The Mediating Role of Biomarkers in the Association Between Subjective Aging and Episodic Memory.

OBJECTIVES: Subjective aging, indexed by subjective age and self-perceptions of aging (SPA), is consistently related to cognition in adulthood. The present study examined whether blood biomarkers mediate the longitudinal associations between subjective aging indices and memory. METHODS: Data of 5,369 individuals aged 50-94 years (mean = 66.89 years, SD = 9.22; 60% women) were drawn from the Health and Retirement Study (HRS). Subjective age, SPA, and demographic factors were assessed in 2012/2014. Interleukin-6, C-reactive protein, albumin, cystatin C, N-terminal pro B-type natriuretic peptide (NT-proBNP), fasting glucose, Vitamin D, hemoglobin, red cells distribution width, and epigenetic aging were assessed as part of the HRS Venuous Blood Study in 2016. Memory was measured in 2018. The mediators (except for epigenetic aging, which was assessed in a subsample) were tested simultaneously in models that accounted for demographic covariates. RESULTS: An older subjective age was related to worse memory partially through higher fasting glucose, higher cystatin C, higher NT-proBNP, and accelerated epigenetic aging. Negative SPA was related to worse memory through lower Vitamin D3, higher fasting glucose, higher cystatin C, higher NT-proBNP, and accelerated epigenetic aging. The biomarkers explained between 2% and 10% of subjective age and between 1% and 8% of SPA associations with memory. Additional analysis revealed that biomarkers continued to be significant mediators when physical inactivity and depressive symptoms were included as additional mediators. CONCLUSION: The present study adds to existing research on the association between subjective aging and memory by providing new evidence on the biological mediators of this association.

Facets of Personality and Risk of Cognitive Impairment: Longitudinal Findings in a Rural Community from Sardinia.

BACKGROUND: Few studies have examined the associations between personality facets and dementia risk and rarely included individuals from rural settings or with low education. OBJECTIVE: To examine the association between personality and the risk of cognitive impairment. METHODS: Participants (N = 1,668; age 50 to 94 at baseline; 56.4% women; 86.5% less than high school diploma) were from a rural region of Sardinia (Italy) who completed the Revised NEO Personality Inventory (NEO-PI-R) during the first wave (2001-2004) and the Mini-Mental State Examination (MMSE) at waves two to five (2005-2021). Cox regression was used to test personality and covariates as predictors of cognitive impairment based on MMSE education-adjusted cutoffs. RESULTS: During the up to 18-year follow-up (M = 10.38; SD = 4.76), 187 individuals (11.2%) scored as cognitively impaired. Participants with higher neuroticism (particularly the depression facet [HR = 1.22, 95% CI = 1.06-1.40]), and lower agreeableness (particularly the modesty facet [HR = 0.83, 95% CI = 0.71-0.97]) and lower conscientiousness (particularly the dutifulness facet [HR = 0.78, 95% CI = 0.67-0.92]) were at higher risk of cognitive impairment. Lower warmth ([HR = 0.75, 95% CI = 0.65-0.87], facet of extraversion) and ideas ([HR = 0.76, 95% CI = 0.65-0.89], facet of openness) were also associated with increased risk of impairment. These associations were virtually unchanged in models that accounted for other risk factors, including smoking, depression, obesity, hypertension, diabetes, and apolipoprotein E (APOE) ɛ4 carrier status. Across the five domains, sex and the APOE variant did not moderate the associations. CONCLUSION: In a sample with demographic characteristics underrepresented in dementia research, this study identifies personality domains and facets most relevant to the risk of cognitive impairment.

Personality and change in perceived control during the acute stage of the coronavirus pandemic.

Lower perceived control (PC) is related to maladaptive psychological responses to stressful events, yet it is unclear whether longer-term situations are associated with PC change over time. This study examined PC change during the beginning of the coronavirus pandemic and whether trajectories varied by age and personality. Personality was assessed in 2455 U.S. adults (18-100 years) from an online study conducted January-February 2020. PC was assessed across three follow-ups (March-July 2020). Latent growth curves modeled PC change. In controlled models, PC decreased (ß = -0.107, p = .005). Older adults had higher PC than younger adults (ß = 0.012, p = .001), and experienced less PC decline (ß = 0.012, p < .001). All personality traits but Openness were related to PC at baseline (ßs ranged from -0.912 to 0.543, ps < .001). Conscientiousness (ß = 0.155, p = .002), Extraversion (ß = 0.128, p = .008), and Agreeableness (ß = 0.099, p = .044) were associated with less PC decline. Employment (ß = 0.160, p = .022), health (ß = 0.133, p = .002), and disease burden (ß = -0.056, p = .014) were also associated with PC change. These results were largely driven by the financial dimension of PC. This study provides evidence for PC change during the COVID-19 pandemic and identifies sociodemographic, personality, and health moderators of PC trajectory.

Self-rated health and incident dementia over two decades: Replication across two cohorts.

This prospective study examined the association between self-rated health and incident dementia in two large cohorts of middle-aged and older adults. Participants were drawn from the Health and Retirement Study (HRS, N = 13,839, Mean Age = 64.32, SD = 9.04) and the English Longitudinal Study of Ageing (ELSA, N = 4649, Mean Age = 64.44, SD = 9.97). Self-rated health and covariates were assessed at baseline in 1998 and 2002, and cognitive status was tracked for up to 21 years in HRS and 17 years in ELSA, respectively. Controlling for demographic factors, poorer self-rated health was associated with higher risk of incident dementia in HRS (HR: 1.18, 95%CI: 1.12-1.24, p < .001) and ELSA (HR: 1.38, 95%CI: 1.23-1.55, p < .001). These associations remained significant when diabetes, hypertension, smoking, physical inactivity, depressive symptoms, personality, and polygenic risk for Alzheimer's Disease were included as additional covariates or when cases occurring within the first ten years of follow-up were excluded from the analyses. There was no replicable evidence that age, sex, education, race or ethnicity moderated the association. Self-rated health is a long-term, replicable predictor of incident dementia that is independent of genetic, clinical, and behavioral risk factors.

Neuroticism and Risk of Parkinson's Disease: A Meta-Analysis.

BACKGROUND: Neuroticism is linked to mood disorders and Alzheimer's disease, but fewer studies have tested the prospective association with Parkinson's disease (PD). OBJECTIVES: To examine the association between neuroticism and risk of PD in a large cohort and a meta-analysis of prospective cohort studies. METHODS: Participants from the UK Biobank (N = 490,755) completed a neuroticism scale in 2006-2010. Incident PD was ascertained using electronic health records or death records up to 2018. The systematic search and meta-analysis followed the MOOSE guidelines. RESULTS: During 11.91 years of follow-up (mean = 8.88 years; 4,360,105 person-years) 1142 incident PD cases were identified. Neuroticism was associated with higher risk of incident PD, both as continuous (HR = 1.28; 95% CI: 1.21-1.36) and categorical variable (top vs. bottom quartiles: HR = 1.88; 95% CI: 1.60-2.22). The association remained significant after accounting for age, sex, smoking, physical activity, anxiety, and depressed mood, and after excluding cases that occurred within the first 5 years of follow-up. The associations were similar for women and men and across levels of socioeconomic status. Random-effect meta-analysis of four prospective studies (N = 548,284) found neuroticism associated with increased risk of incident PD (HR = 1.82; 95% CI: 1.59-2.08; P = 7.31-19 ). There was no evidence of heterogeneity across studies with follow-ups ranging from one to four decades. CONCLUSION: The results from the large UK Biobank and meta-analysis of prospective studies indicate that neuroticism is consistently associated with a higher risk of incident PD. © 2021 International Parkinson and Movement Disorder Society.

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.

Predicting Cognitive Impairment and Dementia: A Machine Learning Approach.

BACKGROUND: Efforts to identify important risk factors for cognitive impairment and dementia have to date mostly relied on meta-analytic strategies. A comprehensive empirical evaluation of these risk factors within a single study is currently lacking. OBJECTIVE: We used a combined methodology of machine learning and semi-parametric survival analysis to estimate the relative importance of 52 predictors in forecasting cognitive impairment and dementia in a large, population-representative sample of older adults. METHODS: Participants from the Health and Retirement Study (N = 9,979; aged 50-98 years) were followed for up to 10 years (M = 6.85 for cognitive impairment; M = 7.67 for dementia). Using a split-sample methodology, we first estimated the relative importance of predictors using machine learning (random forest survival analysis), and we then used semi-parametric survival analysis (Cox proportional hazards) to estimate effect sizes for the most important variables. RESULTS: African Americans and individuals who scored high on emotional distress were at relatively highest risk for developing cognitive impairment and dementia. Sociodemographic (lower education, Hispanic ethnicity) and health variables (worse subjective health, increasing BMI) were comparatively strong predictors for cognitive impairment. Cardiovascular factors (e.g., smoking, physical inactivity) and polygenic scores (with and without APOEɛ4) appeared less important than expected. Post-hoc sensitivity analyses underscored the robustness of these results. CONCLUSIONS: Higher-order factors (e.g., emotional distress, subjective health), which reflect complex interactions between various aspects of an individual, were more important than narrowly defined factors (e.g., clinical and behavioral indicators) when evaluated concurrently to predict cognitive impairment and dementia.

Personality traits and preventive cancer screenings in the Health Retirement Study.

The Five-Factor model of personality has been associated with a wide range of health behaviors and health outcomes. However, few studies have examined whether personality traits are related to cancer screening in older adults. The present study investigated the cross-sectional associations between personality traits and the probability of obtaining a recent preventive screening for breast, cervical, prostate, and colorectal cancer. Participants from the Health and Retirement Study (N = 14,394, Mage = 68.14 years, range = 50-102 years, 58.6% female) completed a personality inventory and reported on cancer screenings in the 2010-2012 assessment. Logistic regression models were used to analyze the data, including age, race, ethnicity, gender, education, income, and wealth as covariates. Higher conscientiousness was associated with a higher likelihood of obtaining breast, cervical, and prostate screening. Higher extraversion was related to higher odds of breast, cervical, and colorectal screening. Higher neuroticism was linked to higher odds of colorectal screening, and conscientiousness moderated the link between neuroticism and cervical screening. These associations were significant in models that accounted for demographic and socioeconomic factors. The effect sizes were in the range of a 10-20% higher likelihood of cancer screening for 1 SD difference in personality. The present findings suggest that conscientiousness and extraversion were related to preventive cancer screenings, whereas neuroticism, openness and agreeableness were largely unrelated to the likelihood of such screenings. If these results are further replicated, health policy makers may consider personality traits when planning and implementing screening recommendations to improve preventive medicine.