Effect of Personality Traits on Risk of Incident Pre‐dementia Syndromes

Abstract

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.

The five‐factor model (neuroticism, extraversion, openness, agreeableness, and conscientiousness) is widely used to describe and define aspects of personality.1 Longitudinal associations between personality traits with cognitive outcomes in older adults have been described, and they link neuroticism and conscientiousness to incident cognitive syndromes.2–7 However, results regarding effects of other personality traits on cognitive states are more mixed. Several studies have reported associations between lower levels of openness and increased risk for mild cognitive impairment (MCI)5 and Alzheimer’s disease,8 whereas others report no association.6 An association between lower agreeableness and increased risk for dementia was reported in one study3 but not in others.7 Extraversion was not associated with risk for MCI or dementia in previous studies.7 The mixed results reported for certain personality traits may be due to the relationship between certain personality traits and specific cognitive domains.9 The association between personality traits and motoric cognitive risk (MCR) syndrome10 was recently examined.11 MCR builds on the operational definition of MCI, substituting the objective cognitive criterion assessed through neuropsychological testing with slow gait, increasing clinical accessibility.10, 12 MCR is common in older adults and predictive of dementia.10, 12 Only partial overlap between individuals diagnosed with MCR and MCI syndromes was reported,10, 12 indicating that risk factors and cognitive trajectories for these syndromes may vary. Stephan et al identified cross‐sectional associations of prevalent MCR with lower openness, extraversion, and conscientiousness as well as higher neuroticism in two large aging cohorts.11
This prospective study builds on previous research to examine whether the five major personality traits1 are associated with risk of incident pre‐dementia syndromes, MCR and MCI syndromes, as well as MCI subtypes (amnestic and non‐amnestic MCI). We hypothesized that higher levels of openness and conscientiousness would be associated with a lower risk of MCR and MCI, and higher levels of neuroticism would be associated with an increased risk of MCI and MCR. We did not expect to find a relationship between agreeableness with either pre‐dementia syndrome, and we expected to find a relationship between extraversion and MCR alone.

METHODS

Participants

We studied community‐residing adults age 65 years and older enrolled in the Central Control of Mobility in Aging (CCMA) study. The primary goal of CCMA is to determine cognitive control of mobility.13, 14 CCMA procedures have been reported.13, 14 In brief, potential participants were identified from a Westchester County registered voter list that included individuals aged 65 years and older who voted in local or national elections in the past 2 years. They were first contacted by mail and then by telephone inviting them to participate. Potential participants were assessed for eligibility using a structured telephone screening interview and to rule out dementia using cognitive screeners.13, 14 Exclusion criteria included inability to speak English, inability to ambulate independently, presence of dementia (previous physician diagnosis or using cut scores on the validated cognitive screeners15, 16), significant loss of vision and/or hearing, current or history of neurologic or psychiatric disorders, recent or anticipated medical procedures that may affect mobility, and receiving hemodialysis.
Eligible individuals were scheduled for in‐person visits at the research center. During study visits, participants received comprehensive cognitive, psychological, and mobility assessments. Neuropsychological tests were administered by research assistants under the supervision of a licensed neuropsychologist and included a test of general cognitive function, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS),17 as well as tests to assess various cognitive domains including the Digit Symbol Substitution Test (subtest of Wechsler Adult Intelligence Scale‐Third Edition),18 the Trail Making Test,19 Free and Cued Selective Reminding Test,20 Controlled Oral Word Association Test‐Semantic and Phonemic Fluency,21 and Boston Naming Test.22 Diagnosis of dementia was assigned according to the Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM‐IV )23 at consensus diagnostic case conferences, as previously described.24 CCMA participants were followed longitudinally at yearly intervals. The study protocols were approved by the Albert Einstein College of Medicine institutional review board, and written informed consent was obtained at study visits.

The Big Five Inventory

The Big Five Inventory (BFI) is a 44‐item self‐report measure designed to assess five dimensions of personality25 (neuroticism, extraversion, conscientiousness, agreeableness, and openness).1 Participants were asked by trained research assistants to rate the extent to which they agreed or disagreed with each item using a 5‐point Likert scale where 1 = “Disagree strongly” and 5 = “Agree strongly.” Scores range from 0 to 40 for each of the five personality traits. The scale was shown to have good validity and reliability (α = .83) in previous studies.26

Pre‐Dementia Syndrome Diagnoses

MCI and MCR diagnostic procedures in CCMA were reported,12, 24, 27 based on published guidelines.28 In brief, nondemented participants with subjective cognitive complaints but without a dementia diagnosis or functional limitations were classified as amnestic MCI if they had impairments on tests of the memory domain or non‐amnestic MCI if they had impairments on tests of nonmemory domains. Impairment was defined as 1.5 standard deviations (SDs) below age‐ and education‐adjusted norms on relevant cognitive tests. MCI was diagnosed at consensus case conferences attended by study clinicians and neuropsychologists using DSM‐IV criteria.23
MCR syndrome is defined as the presence of subjective cognitive complaints and slow gait speed in older individuals without dementia or mobility disability.10, 12, 29 Subjective cognitive complaints were assessed by a score of 1 or higher on the AD8‐dementia screener15 or a “yes” response to the memory item on the Geriatric Depression Scale (GDS) (“Do you feel that you have more problems with memory than most?”).30 Gait speed at “normal pace” was measured on a computerized walkway (180 × 35.5 × .25 inches) with embedded pressure sensors (GAITRite; CIR Systems, Franklin, NJ).31 From footfalls recorded on the walkway, the software computes gait parameters including gait speed (cm/s). GAITRite is widely used and has excellent reliability.31 Slow gait was defined as walking speed 1 SD or more below age‐ and sex‐specific means.10, 12, 29
https://onlinelibrary.wiley.com/doi/full/10.1111/jgs.16424