A novel approach to model cumulative stress: Area under the s-factor curve

OBJECTIVE

Using a large longitudinal sample of adults from the Midlife in the United States (MIDUS) study, the present study extended a recently developed hierarchical model to determine how best to model the accumulation of stressors, and to determine whether the rate of change in stressors or traditional composite scores of stressors are stronger predictors of health outcomes.

METHOD

We used factor analysis to estimate a stress-factor score and then, to operationalize the accumulation of stressors we examined five approaches to aggregating information about repeated exposures to multiple stressors. The predictive validity of these approaches was then assessed in relation to different health outcomes.

RESULTS

The prediction of chronic conditions, body mass index, difficulty with activities of daily living, executive function, and episodic memory later in life was strongest when the accumulation of stressors was modeled using total area under the curve (AUC) of estimated factor scores, compared to composite scores that have traditionally been used in studies of cumulative stress, as well as linear rates of change.

CONCLUSIONS

Like endogenous, biological markers of stress reactivity, AUC for individual trajectories of self-reported stressors shows promise as a data reduction technique to model the accumulation of stressors in longitudinal studies. Overall, our results indicate that considering different quantitative models is critical to understanding the sequelae and predictive power of psychosocial stressors from midlife to late adulthood.

Loneliness, epigenetic age acceleration, and chronic health conditions

Having associations with a range of adverse physical health outcomes including mortality, loneliness is increasingly recognized as a pressing public health concern, but the mechanisms studied to date do not yet explain all loneliness-related health risk. We sought to evaluate whether epigenetic influences on DNA methylation could help explain the relationship between loneliness and health. To do so, we first estimated associations between loneliness and epigenetic age acceleration (EAA) in a subsample of participants in the study of midlife in the United States (n = 1,310), before testing whether EAA mediated and/or moderated the association between loneliness and the onset of chronic health conditions in older adulthood (n = 445 completing longitudinal follow-ups). Greater loneliness was weakly associated with greater EAA in the Horvath, DunedinPACE, and GrimAge measures after accounting for demographic (0.08 ≤ β ≤ 0.11) and behavioral (0.06 ≤ β ≤ 0.08) covariates. Loneliness also predicted increases in chronic condition counts and these effects were more pronounced for individuals with higher DunedinPACE EAA values (interaction term β = 0.09, p = .009), suggesting possible synergistic impacts. EAA measures appear to be promising in helping to understand individual variations in the health impacts of loneliness, but the specific mechanisms involved require further research. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Connecting loneliness with pathological personality traits: Evidence for genetic and environmental mediation from a study of older twins

Loneliness has broad public health importance, especially in older adulthood, and there is some evidence suggesting it is associated with several personality disorders (PDs). The etiology of these PD-loneliness associations, however, has rarely been studied, especially in the context of the maladaptive traits of the DSM-5 alternative model of personality disorder (AMPD). To address these limitations, we estimated phenotypic, genetic, and unique environmental associations between loneliness and maladaptive personality traits in a sample of older adults from the Minnesota Twin Registry (n = 1,356, Mage = 70.4). Loneliness was moderately to strongly associated with each of the AMPD domains of negative affect, detachment, antagonism, disinhibition, and psychoticism (r = .22-.58), with evidence of both genetic (rg = .45-.75) and unique environmental (re = .10-.48) influences explaining the associations to varying degrees. We argue that loneliness may be an underappreciated concomitant of personality pathology, with PD traits perhaps underlying its development. Indeed, these findings suggest that loneliness may be a manifestation of the genetic and environmental forces that also lead to pathological personality variation. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

How does loneliness "get under the skin" to become biologically embedded?

Loneliness is linked to declining physical health across cardiovascular, inflammatory, metabolic, and cognitive domains. As a result, loneliness is increasingly being recognized as a public health threat, though the mechanisms that have been studied do not yet explain all loneliness-related health risk. Potential mechanisms include loneliness having 1.) direct, causal impacts on health, possibly maintained by epigenetic modification, 2.) indirect effects mediated through health-limiting behaviors, and 3.) artifactual associations perhaps related to genetic overlap and reverse causation. In this scoping review, we examine the evidence surrounding each of these pathways, with a particular emphasis on emerging research on epigenetic effects, in order to evaluate how loneliness becomes biologically embedded. We conclude that there are significant gaps in our knowledge of how psychosocial stress may lead to physiological changes, so more work is needed to understand if, how, and when loneliness has a direct influence on health. Hypothalamic-pituitary adrenocortical axis disruptions that lead to changes in gene expression through methylation and the activity of transcription factor proteins are one promising area of research but are confounded by a number of unmeasured factors. Therefore, wok is needed using causally informative designs, such as twin and family studies and intensively longitudinal diary studies.

Assessing the measurement invariance of the Personality Inventory for DSM-5 across Black and White americans

The Personality Inventory for DSM-5 (PID-5) is the primary tool for assessing maladaptive personality traits within the DSM-5 alternative model for personality disorders. Evidence has begun to accumulate on the replicability and measurement invariance of its five-domain factor structure across countries, clinical and community populations, and sex, but its equivalency across racial groups within a given country is largely unstudied. Attempting to replicate the evidence of noninvariance demonstrated by Bagby et al. (2022), we examined the factor structure of the PID-5 across White Americans (n = 612) and Black Americans (n = 613) within the United States. The five-domain structure emerged across both samples with reasonably congruent factor loadings. Therefore, we tested for measurement invariance using the 13-step framework advocated by Marsh et al. (2009) for personality data. We found support for the PID-5's comparability across racial groups, offering some preliminary backing for its use with Black Americans, though additional evidence is needed to clarify the conflicting results and further validate the instrument. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Comparing Phenotypic, Genetic, and Environmental Associations between Personality and Loneliness

As a strong risk factor for mortality, individual differences in loneliness are of clear public health significance. Four of the Big Five traits have emerged as cross-sectional correlates, but the etiology of these links is unclear, as are relations with more specific personality facets. Thus, we estimated phenotypic, genetic, and environmental associations between loneliness and both broader and narrower personality dimensions. Traits that indexed Negative Emotionality (e.g., Neuroticism, Stress Reactivity, Alienation) and low Positive Emotionality (e.g., low Extraversion, low Well-Being) had the strongest associations with loneliness, though low Conscientiousness, low Agreeableness, and high Aggression were also implicated. These associations were explained by both genetic (0.30<|rg|<0.80) and unique environmental (0.10<|re|<0.35) influences, consistent with an etiology of loneliness involving several personality domains.

Comparing associations between personality and loneliness at midlife across three cultural groups

OBJECTIVE

Loneliness represents a public health threat given its central role in predicting adverse mental and physical health outcomes. Prior research has established four of the Big Five personality traits as consistent cross-sectional predictors of loneliness in largely western, White samples. However, it is not clear if the personality predictors of loneliness vary across cultures.

METHOD

The present study estimates associations between the Big Five traits and loneliness across distinct samples of White American, Black American, and Japanese adults (n = 6051 at T1). Confirmatory factor analysis and exploratory structural equation modeling were used to examine measurement invariance properties of the Big Five and loneliness across these groups. The factor structures were then carried forward to estimate associations between personality and loneliness across two assessments waves using structural equation modeling.

RESULTS

While Neuroticism was a strong predictor across groups, low Extraversion was more predictive of loneliness in Japan than in the U.S., and low Conscientiousness was only a significant predictor in the U.S.

CONCLUSIONS

Previous literature offers a framework for interpreting these findings in that loneliness may be shaped comparatively more through interconnectedness in Japanese culture, while, in the U.S., individual goals and personal romantic expectations are more salient.