Personality traits and polypharmacy: meta-analysis of five samples.

OBJECTIVE: The present study examined the prospective relationship between personality traits and the risk of polypharmacy. METHODS AND MEASURES: Participants (age range: 16-101 years; N > 15,000) were from the English Longitudinal Study of Ageing (ELSA), the Midlife in the United States Study (MIDUS), the Health and Retirement Study (HRS), the Wisconsin Longitudinal Study of Aging (WLS), and the Longitudinal Internet Studies for the Social Sciences (LISS). In each sample, personality traits and demographic factors were assessed at baseline. Number of medications was obtained from 2 to 20 years later. RESULTS: Random-effect meta-analyses revealed that higher neuroticism was related to a higher risk of polypharmacy (Odd Ratio = 1.30; 95% CI 1.17-1.46) and excessive polypharmacy (Odd Ratio = 1.44; 95% CI 1.18-1.77) whereas higher conscientiousness (Odd Ratio = 0.84; 95% CI 0.74-0.95) and extraversion (Odd Ratio = 0.85; 95% CI 0.73-0.98) were associated with a lower risk of polypharmacy. Openness and agreeableness were unrelated to polypharmacy. Body mass index, number of chronic conditions, and depressive symptoms partially mediated the association between personality and the number of medications. CONCLUSION: The present study provides replicable and robust evidence that neuroticism is a risk factor for simultaneous use of multiple medications, whereas conscientiousness and extraversion may play a protective role.

German population norms of the preference to solitude scale and its correlates.

AIM: Our first aim was to present norm values for the Preference for Solitude Scale by sex, age, and other sociodemographic groups. Our second aim was to evaluate the correlates of preference for solitude. METHODS: Data were collected in August/September 2023 from a sample of individuals (N = 5000) living in Germany aged 18 to 74 years (ensuring representativeness in terms of sex, age group and federal state for the German general adult population). The established and valid Preference for Solitude Scale (range 0 to 12, with higher values reflecting a stronger preference for solitude) was used to quantify the preference for solitude. Norm values were provided by sex and age groups. Multiple linear regressions were used to examine the correlates of preference for solitude. RESULTS: Average preference for solitude score was 7.6 (SD = 3.0; 0 to 12). The average score was 7.3 (SD = 3.0) among males and 7.9 (SD = 2.9) among females. Regressions showed that a stronger preference for solitude was associated with being female (ß = .51, p < .001), being older (e.g., being 40 to 49 years compared to 18 to 29 years, ß = .85, p < .001), being single (e.g., divorced compared to being single, ß = -.78, p < .01), higher level of education (secondary education compared to primary education, ß = .43, p < .01), never been a smoker (e.g., daily smoker compared to never smokers, ß = -.61, p < .001), absence of alcohol consumption (e.g., drinking once a week compared to never drinking, ß = -1.09, p < .001), no sports activity (e.g., 2-4 hours per week compared to no sports activity, ß = -.60, p < .001), poorer self-rated health (ß = .28, p < .001) and more depressive symptoms (ß = .05, p < .001). Sex-stratified regressions yielded similar results. CONCLUSION: Norm values provided in this study can be used as a benchmark for comparison with other countries and can guide further research dealing with preferences for solitude. We demonstrated the importance of several sociodemographic factors (e.g., marital status), lifestyle-related factors (e.g., sports activity), and health-related factors (e.g., depressive symptoms) for the preference for solitude. Such knowledge about the correlates of preference for solitude may help to characterize them. This is essential to ensure a good balance between social interaction and being alone. This is important because preference for solitude is associated with poor self-rated health and depression, but also with healthy behaviors such as abstaining from smoking and drinking.

Purpose in life and stress: An individual-participant meta-analysis of 16 samples.

Background: Purpose in life is a psychological resource that has been associated with better regulation of stress. The present research reports a coordinated analysis of the association between purpose in life and subjective stress and evaluates potential sociodemographic and mental health moderators of this association. Methods: With individual participant data from 16 samples (total N=108,391), linear regression examined the association between purpose in life and general subjective feelings of stress, controlling for sociodemographic characteristics. Results: Greater purpose in life was associated with less subjective stress (meta-analytic estimate=-.228, 95% Confidence Interval=-.292, -.164; p<.001). Interaction terms between sociodemographic factors and purpose tested in the individual samples and synthesized with meta-analysis were not significant, which indicated that the association between purpose and stress was similar across age, sex, race, ethnicity, and education. The association was also not moderated by psychological distress. Meta-regressions further indicated that this association was generally similar across scale length, content of the purpose measure, and across samples from Eastern and Western countries. Limitations: The associations reported are observational. Experimental work is needed to evaluate causality. Conclusions: Purpose in life is associated with less subjective stress across populations. Less subjective stress may be one mechanism through which purpose contributes to better mental and physical health.

Personality nuances and risk of dementia: Evidence from two longitudinal studies.

Personality traits are broad constructs composed of nuances, operationalized by personality items, that can provide a more granular understanding of personality associations with health outcomes. This study examined the associations between personality nuances and incident dementia and evaluated whether nuances associations replicate across two samples. Health and Retirement Study (HRS, N = 11,400) participants were assessed in 2006/2008, and the English Longitudinal Study of Ageing (ELSA, N = 7453) participants were assessed in 2010/2011 on personality and covariates. Dementia incidence was tracked for 14 years in the HRS and 8 years in ELSA. In both HRS and ELSA, higher neuroticism domain and nuances (particularly nervous and worry) were related to a higher risk of incident dementia, whereas higher conscientiousness domain and nuances (particularly responsibility and organization) were associated with a lower risk of dementia. To a lesser extent, higher extraversion (active), openness (broad-minded, curious, and imaginative), and agreeableness (helpful, warm, caring, and sympathetic) nuances were associated with a lower risk of dementia, with replicable effects across the two samples. A poly-nuance score, aggregating the effects of personality items, was associated with an increased risk of incident dementia in the HRS and ELSA, with effect sizes slightly stronger than those of the personality domains. Clinical, behavioral, psychological, and genetic covariates partially accounted for these associations. The present study provides novel and replicable evidence for specific personality characteristics associated with the risk of incident dementia.

Prevalence and factors associated with probable depression among the oldest old during the Covid-19 pandemic: evidence from the large, nationally representative 'Old Age in Germany (D80+)' study.

BACKGROUND: To date, most studies examining the prevalence and determinants of depression among individuals aged 80 and over have used geographically limited samples that are not generalisable to the wider population. Thus, our aim was to identify the prevalence and the factors associated with probable depression among the oldest old in Germany based on nationally representative data. METHODS: Data were taken from the nationally representative 'Old Age in Germany (D80+)' study (n = 8386; November 2020 to April 2021) covering both community-dwelling and institutionalised individuals aged 80 and over. The Short Form of the Depression in Old Age Scale was used to quantify probable depression. RESULTS: Probable depression was found in 40.7% (95% CI: 39.5% to 42.0%) of the sample; 31.3% were men (95% CI: 29.7% to 32.9%) and 46.6% women (95% CI: 44.9% to 48.3%). The odds of probable depression were positively associated with being female (odds ratio (OR): 1.55, 95% CI: 1.30 to 1.84), being divorced (compared to being married, OR: 1.33, 95% CI: 1.01 to 1.76), being widowed (OR: 1.14, 95% CI: 1.00 to 1.30), having a low education (e.g., medium education compared to low education, OR: 0.86, 95% CI: 0.74 to 0.99), living in an institutionalised setting (OR: 2.36, 95% CI: 1.84 to 3.02), living in East Germany (OR: 1.21, 95% CI, 1.05 to 1.39), not having German citizenship (German citizenship compared to other citizenship, OR: 0.55, 95% CI: 0.31 to 0.95), poor self-rated health (OR: 0.31, 95% CI: 0.28 to 0.34), and the number of chronic conditions (OR: 1.12, 95% CI: 1.09 to 1.14). CONCLUSION: About four out of 10 individuals aged 80 and over in Germany had probable depression, underlining the importance of this challenge. Knowledge of specific risk factors for this age group may assist in addressing older adults at risk of probable depression.

Personality traits and the risk of urinary incontinence: Evidence from three longitudinal samples.

OBJECTIVE: Urinary incontinence (UI) is a common condition with a substantial negative impact on older adults' quality of life. This study examines whether individual differences in behavioral, cognitive, and emotional traits assessed by the five major dimensions of personality are related to the risk of concurrent and incident UI. METHODS: Participants were older women and men (N > 26,000) from the Midlife in the United States Survey, the Health and Retirement Study, and the English Longitudinal Study of Aging. In each cohort, personality traits (measured with the Midlife Development Inventory) and demographic (age, sex, education, and race), clinical (body mass index, diabetes, blood pressure), and behavioral (smoking) factors were assessed at baseline. UI was assessed at baseline and again 8-20 years later. Results for each cohort were combined in random-effect meta-analyses. RESULTS: Consistently across cohorts, higher neuroticism and lower conscientiousness were related to a higher risk of concurrent and incident UI. To a lesser extent, extraversion, openness, and agreeableness were also related to lower risk of concurrent and incident UI. BMI, diabetes, blood pressure, and smoking partially accounted for these associations. There was little evidence that age or sex moderated the associations. CONCLUSIONS: The present study provides novel, robust, and replicable evidence linking personality traits to UI. The higher vulnerability for UI for individuals who score higher on neuroticism and lower on conscientiousness is consistent with findings for other multifactorial geriatric syndromes. Personality traits can help identify individuals at risk and may help contextualize the clinical presentation of comorbid emotional, cognitive, and behavioral symptoms.

Personality and Risk of Arthritis in Six Longitudinal Samples.

OBJECTIVES: Personality traits are broadly related to medical conditions, but there is limited research on the association with the risk of arthritis. This multi-cohort study examines the concurrent and prospective associations between personality traits and arthritis risk. METHOD: Participants (N > 45,000) were mostly middle-aged and older adults from six established longitudinal cohorts. Baseline assessments of personality traits, covariates (age, sex, education, race, ethnicity, depressive symptoms, body mass index, and smoking), and arthritis diagnosis were obtained in each sample. Arthritis incidence was assessed over 8 to 20 years of follow-up. RESULTS: The meta-analyses identified an association between higher neuroticism and an increased risk of concurrent (Odds Ratio= 1.20, 95% CI=1.16-1.24; p<.001, I2= 40.27) and incident (Hazard Ratio= 1.11, 95% CI=1.08-1.14; p<.001, I2= 0) arthritis and between higher conscientiousness and a decreased risk of concurrent (Odds Ratio = 0.88, 95% CI=0.86-0.90; p<.001, I2= 0) and incident (Hazard Ratio= 0.95, 95% CI=0.92-0.98; p=.002, I2= 41.27) arthritis. Higher extraversion was linked to lower risk of concurrent (Odds Ratio= 0.92, 95% CI=0.88-0.96; p<.001, I2= 76.09) and incident (Hazard Ratio= 0.97, 95% CI=0.95-0.99; p=.018, I2= 0) arthritis, and openness was related to lower risk of concurrent arthritis (Odds Ratio= 0.96, 95% CI=0.93-0.99; p=.006, I2= 35.86). Agreeableness was unrelated to arthritis. These association were partially accounted by depressive symptoms, body mass index, and smoking. There was no consistent evidence of moderation by age or sex. DISCUSSION: Findings from six samples point to low neuroticism and higher conscientiousness as factors that reduce risk of arthritis.

Purpose in life and cognitive health: a 28-year prospective study.

OBJECTIVES: To examine the prospective association between purpose in life measured at three points across middle and older adulthood and cognitive outcomes assessed 8-28 years later. DESIGN: Prospective Study. SETTING: Wisconsin Longitudinal Study of Aging (WLS). PARTICIPANTS: WLS participants who reported on their purpose in life at Round 4 (1992-1994; Mage = 52.58), Round 5 (2003-2007; Mage = 63.74), and/or Round 6 (2010-2012; Mage = 70.25) and were administered a cognitive battery at Round 7 (2020; Mage = 79.94) were included in the analysis (N = 4,632). MEASUREMENTS: Participants completed the Ryff measure of purpose in life and were administered the telephone interview for cognitive status and measures of verbal fluency, digit ordering, and numeric reasoning. RESULTS: Purpose in life measured at age 52 was related to better global cognitive function and verbal fluency but unrelated to dementia at age 80. In contrast, purpose in life at ages 63-70 was associated with lower likelihood of dementia, as well as better global cognitive function and verbal fluency at age 80. The effect sizes were modest (median Beta coefficient = .05; median odds ratio = .85). A slightly steeper decline in purpose in life between ages 52 and 70 was found for individuals with dementia at age 80. CONCLUSIONS: Purpose in life is associated with healthier cognitive function measured up to 28 years later. Individuals with lower purpose, especially in their 60s or older, and with steeper declines in purpose, are more likely to have dementia at age 80.

Purpose in Life and Risk of Falls: A Meta-Analysis of Cross-Sectional and Prospective Associations.

Background and Aim: Purpose in life is an aspect of well-being that is associated with better health outcomes in older adulthood. We examine the association between purpose in life and likelihood of a recent fall and risk of an incident fall over time. Methods: Purpose in life and falls were reported concurrently and falls were reported again up to 16 years later in four established longitudinal studies of older adults (total N = 25,418). Results: A random-effects meta-analysis of the four samples indicated that purpose was associated with a 14% lower likelihood of having fallen recently at baseline (meta-analytic OR = 0.88, 95% CI [0.84-0.92]). Among participants who reported no falls at baseline (N = 15,632), purpose was associated with a nearly 10% lower risk of an incident fall over the up to 16-year follow-up (meta-analytic HR = 0.92, 95% CI [0.90-0.94]). These associations were independent of age, sex, race, ethnicity, and education, were not moderated by these factors, and persisted controlling for physical activity and disease burden. Conclusion and Recommendations: Purpose in life is a meaningful aspect of well-being that may be useful to identify individuals at risk for falling, particularly among individuals without traditional risk factors, and be a target of intervention to reduce fall risk.

The Association between Happiness and Cognitive Function in the UK Biobank.

Feelings of happiness have been associated with better performance in creative and flexible thinking and processing. Less is known about whether happier individuals have better performance on basic cognitive functions and slower rate of cognitive decline. In a large sample from the UK Biobank (N=17,885; Age 40-70 years), we examine the association between baseline happiness and cognitive function (speed of processing, visuospatial memory, reasoning) over four assessment waves spanning up to 10 years of follow-up. Greater happiness was associated with better speed and visuospatial memory performance across assessments independent of vascular or depression risk factors. Happiness was associated with worse reasoning. No association was found between happiness and the rate of change over time on any of the cognitive tasks. The cognitive benefits of happiness may extend to cognitive functions such as speed and memory but not more complex processes such as reasoning, and happiness may not be predictive of the rate of cognitive decline over time. More evidence on the association between psychological well-being and different cognitive functions is needed to shed light on potential interventional efforts.

Purpose in Life and Cognitive Function: Evidence for Momentary Associations in Daily Life.

Background and Objectives: Purpose in life is associated with healthier cognitive outcomes in older adulthood. This research examines within-person dynamics between momentary purpose and cognitive function to provide proof of concept that increases in purpose are associated with better cognitive performance. Research Design and Methods: Participants (N = 303; 54% female; Mage = 51.71, SD = 7.32) completed smartphone-based momentary assessments of purpose and short cognitive tasks 3 times a day for 8 days. Results: In moments when participants felt more purpose driven than their average, they had faster processing speed (b = -1.240, SE = 0.194; p < .001), independent of person, temporal, and contextual factors and practice effects. Momentary purpose was unrelated to visual working memory performance (b = -0.001, SE = 0.001; p = .475). In contrast to purpose, momentary hedonic affect (e.g., happiness) was unrelated to momentary cognition. Discussion and Implications: Feeling more momentary purpose may support faster processing speed in daily life. Such evidence provides stage 0 support for a purpose-based intervention for healthier cognition, which may be particularly useful in middle adulthood and the transition to older adulthood before the onset of cognitive impairment.

Personality and cognitive errors in the Healthy Aging in Neighborhoods of Diversity across the Life Span study.

This study examines the association between personality and cognitive errors in the Healthy Aging in Neighborhoods of Diversity across the Life Span study, a sample diverse across race (Black, White) and SES (above, below 125% of the federal poverty line). Participants (N=1,062) completed a comprehensive personality questionnaire and were administered a brief mental status screener of cognitive errors. Higher neuroticism was associated with more cognitive errors, whereas higher openness and conscientiousness were associated with fewer errors. These associations were independent of age, sex, race, poverty status, and education and were generally not moderated by these factors. These findings support the associations between personality and cognition across race and SES.

Physical, cognitive, and social activities as mediators between personality and cognition: evidence from four prospective samples.

OBJECTIVES: The present study examined how activity engagement mediates the association between personality and cognition. METHODS: Participants were middle-aged and older adults (Age range: 24-93 years; N > 16,000) from the Midlife in the United States Study, the Health and Retirement Study, the English Longitudinal Study of Ageing, and the Wisconsin Longitudinal Study of Aging. In each sample, personality traits and demographic factors were assessed at baseline, engagement in cognitive, physical, and social activities was assessed in a second wave, and cognition was measured in a third wave, 8 to 20 years later. RESULTS: Random-effect meta-analyses indicated that lower neuroticism and higher extraversion, openness, and conscientiousness were prospectively associated with better cognition. Most of these associations were partly mediated by greater engagement in physical and cognitive activities but not social activities. Physical activity accounted for 7% (neuroticism) to 50% (extraversion) and cognitive activity accounted for 14% (neuroticism) to 45% (extraversion) of the association with cognition. CONCLUSION: The present study provides replicable evidence that physical and cognitive activities partly mediate the prospective association between personality traits and cognitive functioning.

Meaning in life and Parkinson's disease in the UK Biobank.

Introduction: Meaning in life is an aspect of eudaimonic well-being associated with lower dementia risk. This research examines whether this protective association extends to Parkinson's disease (PD). Methods: Participants (N = 153,569) from the UK Biobank reported on their meaning in life. Cases of PD were identified through health records. Results: Meaning in life was associated with a 50 % lower likelihood of prevalent PD (OR = 0.68, 95 % CI = 0.59-0.78). Over the 5-year follow-up, meaning was associated with a 35 % lower risk of incident PD (HR = 0.74, 95 % CI = 0.65-0.83), an association robust to sociodemographic characteristics, depression, history of seeking mental health care, smoking, physical activity, and genetic risk and not moderated by age, sex, education, deprivation, or genetic risk. Conclusions: Meaning in life is associated with lower risk of incident PD, an association independent of other major risk factors and generalizable across sociodemographic groups. Meaning is a promising target of intervention for common neurodegenerative diseases.

Purpose in life and slow walking speed: cross-sectional and longitudinal associations.

The present research examines the association between purpose in life - a component of well-being defined as the feeling that one's life is goal-oriented and has direction - and slow walking speed and the risk of developing slow walking speed over time. Participants (N = 18,825) were from three established longitudinal studies of older adults. At baseline, participants reported on their purpose in life, and interviewers measured their usual walking speed. Walking speed was measured at annual or biannual follow-up waves up to 16 years later. Random-effects meta-analysis was used to summarize the estimates from the individual studies. Every standard deviation higher in purpose in life (as a continuous measure) was associated with a lower likelihood of cross-sectional slow walking speed at baseline (meta-analytic OR = .80, 95% CI = .77-.83). Among participants who did not have slow walking speed at baseline (n = 8,448), every standard deviation higher purpose in life was associated with a lower likelihood of developing slow walking speed over the up to 16 years of follow-up (meta-analytic HR = .93, 95% CI = .89-.96). Physical activity and disease burden accounted for 25% and 14% of the cross-sectional and longitudinal associations, respectively. The associations were independent of age, sex, race, ethnicity, and education and not moderated by these factors. Higher purpose in life is associated with a lower risk of slow walking speed and a lower risk of developing slow walking speed over time. Purpose in life is a psychological resource that may help to support aspects of physical function, such as walking speed, and may help support better function with age.

Purpose in life and cognitive performance and informant ratings of cognitive decline, affect, and activities.

OBJECTIVE: To examine (1) the association between purpose in life and multiple domains of cognitive function and informant-rated cognitive decline, affect, and activities; (2) whether these associations are moderated by sociodemographic factors, cognitive impairment, or depression; (3) whether the associations are independent of other aspects of well-being and depressive symptoms. METHOD: As part of the 2016 Harmonized Cognitive Assessment Protocol from the Health and Retirement Study, participants completed a battery of cognitive tests and nominated a knowledgeable informant to rate their cognitive decline, affect, and activities. Participants with information available on their purpose in life from the 2014/2016 Leave Behind Questionnaire were included in the analytic sample (N = 2,812). RESULTS: Purpose in life was associated with better performance in every cognitive domain examined (episodic memory, speed-attention, visuospatial skills, language, numeric reasoning; median ß =.10, p <.001; median d =.53). Purpose was likewise associated with informant-rated cognitive decline and informant-rated affective and activity profiles beneficial for cognitive health (median ß =.18, p < .001; median d =.55). There was little evidence of moderation by sociodemographic or other factors (e.g., depression). Life satisfaction, optimism, positive affect, and mastery were generally associated with cognition. When tested simultaneously with each other and depressive symptoms, most dimensions were reduced to non-significance; purpose remained a significant predictor. CONCLUSIONS: Purpose in life is associated with better performance across numerous domains of cognition and with emotional and behavioral patterns beneficial for cognitive health that are observable by knowledgeable others. These associations largely generalize across demographic and clinical groups and are independent of other aspects of well-being.

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.

Physical activity and cognitive function: moment-to-moment and day-to-day associations.

BACKGROUND: The beneficial effect of acute physical exercise on cognitive performance has been studied in laboratory settings and in long-term longitudinal studies. Less is known about these associations in everyday environment and on a momentary timeframe. This study investigated momentary and daily associations between physical activity and cognitive functioning in the context of everyday life. METHODS: Middle-aged adults (n = 291, aged 40-70) were asked to wear accelerometers and complete ecological momentary assessments for eight consecutive days. Processing speed and visual memory were assessed three times per day and self-rated evaluations of daily cognition (memory, thinking, and sharpness of mind) were collected each night. The number of minutes spent above the active threshold (active time) and the maximum vector magnitude counts (the highest intensity obtained) before each cognitive test and at a daily level were used as predictors of momentary cognitive performance and nightly subjective cognition. Analyses were done with multilevel linear models. The models were adjusted for temporal and contextual factors, age, sex, education, and race/ethnicity. RESULTS: When participants had a more active time or higher intensity than their average level within the 20 or 60 minutes prior to the cognitive test, they performed better on the processing speed task. On days when participants had more active time than their average day, they rated their memory in the evening better. Physical activity was not associated with visual memory or self-rated thinking and sharpness of mind. CONCLUSIONS: This study provides novel evidence that outside of laboratory settings, even small increases in physical activity boost daily processing speed abilities and self-rated memory. The finding of temporary beneficial effects is consistent with long-term longitudinal research on the cognitive benefits of physical activity.

Loneliness and Risk of Parkinson Disease.

Importance: Loneliness is associated with morbidity and mortality, including higher risk of neurodegenerative diseases. To our knowledge, no study has examined whether the association between loneliness and detrimental outcomes extends to Parkinson disease (PD). Objective: To assess whether loneliness is associated with risk of incident PD and whether the association is independent of other risk factors or modified by age, sex, and genetic vulnerability. Design, Setting, and Participants: This prospective cohort study included a population-based sample of UK Biobank participants aged 38 to 73 years with loneliness data and without a diagnosis of PD at baseline who were first assessed from March 13, 2006, to October 1, 2010, and followed up to October 9, 2021. Exposure: Feeling lonely and covariates that are known risk factors for or prodromal features of PD. Main Outcome and Measure: Incident PD was ascertained through UK National Health Service health records. Results: Of 491 603 participants (mean [SD] age, 56.54 [8.09] years; 54.4% female), 2822 developed PD during the 15-year follow-up. Individuals who reported being lonely had a higher risk of PD (hazard ratio [HR], 1.37; 95% CI, 1.25-1.51), an association that remained after accounting for demographic factors, socioeconomic status, social isolation, PD polygenetic risk score, smoking, physical activity, body mass index, diabetes, hypertension, stroke, myocardial infarction, depression, and ever seeing a psychiatrist (fully adjusted model: HR 1.25; 95% CI, 1.12-1.39). The association between loneliness and incident PD was not moderated by sex (HR for interaction, 0.98; 95% CI, 95% CI, 0.81-1.18), age (HR for interaction, 0.99; 95% CI, 0.98-1.01), or polygenic risk score (HR for interaction, 0.93; 95% CI, 0.85-1.02). Contrary to expectations for a prodromal syndrome, when stratified by time, loneliness was not associated with risk for incident PD during the first 5 years (HR, 1.15; 95% CI, 0.91-1.45) but was associated with PD risk during the subsequent 10 years (HR, 1.32; 95% CI, 1.19-1.46). Conclusions and Relevance: This large cohort study found that loneliness was associated with risk of incident PD across demographic groups and independent of depression and other prominent risk factors and genetic risk. The findings add to the evidence that loneliness is a substantial psychosocial determinant of health.

Informant-rated change in personality traits, psychological distress, well-being, and social connection with dementia.

OBJECTIVES: Studies of retrospective personality change with dementia consistently find caregivers report large changes in personality (e.g., increases in neuroticism) of their care recipients compared to before dementia. This work seeks to replicate the established pattern of personality change, extend it to change in psychological distress, well-being, and social connection, and evaluate whether changes vary by stage of dementia. METHODS: Caregivers of people with dementia (N = 188) reported on the psychological and social health of their care recipient currently and how they were before they developed dementia. Personality was measured as five factor model traits. Psychological distress was measured as symptoms of depression and anxiety, perceived stress, and pessimism. Psychological well-being was measured as purpose in life, life satisfaction, happiness, self-efficacy, and optimism. Social connection was measured as loneliness, belonging, social support, and social strain. RESULTS: There were substantial increases in neuroticism (d = 1.14) and decreases in the other four personality traits (d range=-0.85 to -1.37). There were significant increases in psychological distress (e.g., d = 1.07 for depression) and substantial decreases in well-being (e.g., d=-1.18 for purpose in life) and social connection (e.g., d=-1.12 for belonging). Change was apparent across dementia stage and generally larger in more severe dementia. DISCUSSION: In addition to personality, there are large retrospective changes in psychological distress, well-being, and social connection with dementia. These quantitative findings complement clinical observations of the natural history of psychosocial changes in people with dementia, and can inform families, clinicians, and researchers on commonly observed changes and improve interventions to mitigate dementia burden.