Do Loneliness and Per Capita Income Combine to Increase the Pace of Biological Aging for Black Adults across Late Middle Age?

Depressive symptoms partially mediate the relationship between psychosocial factors and epigenetic age acceleration in a multi-racial/ethnic sample of older adults

Psychosocial factors, including cumulative psychosocial stress and loneliness, have been linked to epigenetic aging in older adults. Further, depressive symptoms have established relationships with both psychosocial factors and epigenetic aging. However, it is not known whether depressive symptoms mediate the association between psychosocial factors and epigenetic aging.We conducted linear regression models to examine associations between psychosocial stress, loneliness, and depressive symptoms and five epigenetic age acceleration (AA) measures estimated by DNA methylation in a multi-racial/ethnic sample of 2681 older adults from the Health and Retirement Study (mean age: 70.4 years). For all identified associations, we tested for effect modification by sex and educational attainment and performed mediation analysis to characterize the role of depressive symptoms on these associations.Psychosocial stress, loneliness, and depressive symptoms were each associated with at least one measure of epigenetic AA (FDR q < 0.05). Further, we observed interactions between loneliness, psychosocial stress, and sex on DunedinPACE, as well as loneliness and educational attainment on GrimAA, PhenoAA, and DunedinPACE, with females and individuals without a college degree appearing more sensitive to the psychosocial effects on epigenetic aging. Depressive symptoms mediated between 24 % and 35 % of the relationships between psychosocial stress and HannumAA, GrimAA, and DunedinPACE, as well as 40 % and 37 % of the relationships between loneliness and both GrimAA and DunedinPACE, respectively.

Results

from this study may help elucidate the relationship between psychosocial factors and epigenetic aging, which is critical in understanding the biological mechanisms through which psychosocial factors may contribute to age-related disease.

Housing insecurity pathways to physiological and epigenetic manifestations of health among aging adults: a conceptual model

Introduction

Housing insecurity is a social determinant of health, as evidenced by its associations with mental, physical, and biological outcomes. The scientific understanding of the mechanisms by which housing insecurity is associated with health is still limited. This review adapts existing stress process models to propose a conceptual model illustrating potential pathways linking the specific stressor of housing insecurity to physiological and epigenetic manifestations of stress among aging adults.

Methods

This narrative review examines literature across multiple fields, including public health, psychology, and sociology. The literature selected for this review was identified through scientific databases including Web of Science, PubMed, JSTOR, and Google Scholar; primarily peer-reviewed empirical studies, literature reviews, and research reports published in English between 1981 and 2024; and principally based in the United States context. A synthesis of this literature is presented in a proposed conceptual model.

Results

The literature supports the existence of two main predictors of housing insecurity: sociodemographic characteristics and the historical/current context. The main mediating pathways between housing insecurity and manifestations of stress include health behaviors, psychosocial resources, and structural resources. Moderating factors affecting the associations between housing insecurity and manifestations of stress include government assistance, chronic discrimination/unfair treatment, and individual differences. These interdependent mediating and moderating mechanisms affect stressor reactivity, a proximal manifestation of stress, which contributes to the physiological and epigenetic distal manifestations of stress in aging adults.

Discussion and implications

The prevalence of housing insecurity among aging adults is growing in the United States, with significant implications for public health and health disparities, given the growing percentage of aging adults in the population. Further empirical testing of the mediating and moderating mechanisms proposed in the conceptual model will elucidate how housing insecurity is connected to health and provide insight into preventive strategies to ameliorate the adverse effects of housing insecurity on biological health among aging adults.

Associations Between Loneliness, Epigenetic Aging, and Multimorbidity Through Older Adulthood

OBJECTIVES

Loneliness is a pressing public health concern, but the mechanisms by which it leads to declining physical health are uncertain. Prior work has begun to explore epigenetic pathways, with some evidence suggesting a link between loneliness and DNA methylation, though it is unclear whether epigenetic variation can help explain loneliness-health associations.

METHODS

Associations between loneliness and epigenetic age acceleration (EAA) were estimated, as well as the degree to which EAA mediated and moderated the association between loneliness and the development of chronic physical health conditions (multimorbidity) in older adulthood. The sample consisted of Health and Retirement Study participants who provided blood draws and consented to methylation profiling (n = 4,018).

RESULTS

Baseline loneliness was associated with greater EAA in the GrimAge measure net of demographic and behavioral covariates (β = 0.07, p = .003). Loneliness and GrimAge each predicted increasing condition counts, but there was no evidence of an interactive effect. The association between loneliness and increasing condition counts was, however, significantly mediated by GrimAge (indirect path β = 0.020, p = .003).

DISCUSSION

These results suggest that the impact of loneliness on multimorbidity may, in part, operate through DNA methylation. The specific intermediary, physiological mechanisms that are involved will require further research, but EAA measures like GrimAge are promising in helping to understand the health impacts of loneliness.

Epigenetic Aging Associations With Psychoneurological Symptoms and Social Functioning in Adults With Sickle Cell Disease

Objective: Sickle cell disease (SCD), the most common inherited blood disorder in the United States, is associated with severe psychoneurological symptoms. While epigenetic age acceleration has been linked to psychoneurological symptom burden in other diseases, this connection is unexplored in SCD. This study aimed to assess the association between epigenetic age acceleration and psychoneurological symptom burden in SCD. Methods: In this cross-sectional study, emotional impact, pain impact, sleep impact, social functioning, and cognitive function were assessed in 87 adults living with SCD. DNA methylation data were generated from blood specimens and used to calculate epigenetic age using five clocks (Horvath, Hannum, PhenoAge, GrimAge, & DunedinPACE). Associations between epigenetic age acceleration and symptoms were assessed. Results: The sample (N = 87) had a mean (SD) chronologic age was 30.6 (8.1) years. Epigenetic age acceleration was associated with several symptom outcomes. GrimAge age acceleration (β = -0.49, p = .03) and increased DunedinPACE (β = -2.23, p = .004) were associated with worse emotional impact scores. PhenoAge (β = -0.32, p = .04) and the GrimAge (β = -0.48, p = .05) age acceleration were associated with worse pain impact scores. Increased DunedinPACE (β = -2.07 p = .04) were associated with worse sleep impact scores. Increased DunedinPACE (β = -2.87, p = .005) was associated with worse social functioning scores. We did not find associations between epigenetic age acceleration and cognitive function in this sample. Conclusion: Epigenetic age acceleration was associated with worse symptom experiences, suggesting the potential for epigenetic age acceleration as a biomarker to aid in risk stratification or targets for intervention to mitigate symptom burden in SCD.

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).

Incarceration Exposure, Biological Aging, and Depression Symptoms in an African American Sample of Older Adults

Objectives: The study draws upon perspectives on life-course stressors and health to assess whether lifetime incarceration exposure is a determinant of biological aging and self-reported depression. Methods: Using data from a sample of 460 African American participants (average age= 57) in the Family and Community Health Study, the study examined two epigenetic indices of biological aging, DunedinPoAm and GrimAge, as well as a self-reported measure of depression symptoms. Estimates were derived from multivariate regression models with adjustments for selection on observables and confounding factors. Results: Exposure to incarceration was a significant determinant of accelerated biological aging (GrimAge) and the pace of aging (DunedinPoAm) and depressive symptoms. Discussion: Among formerly incarcerated older adults, past experiences with the stressors of incarceration predict key biomarkers of physiological deterioration and depressive symptoms. Incarceration contributes to the mental and physical health burden of older adults.

Racial discrimination during middle age predicts higher serum phosphorylated tau and neurofilament light chain levels a decade later: A study of aging black Americans

INTRODUCTION

Recent evidence suggests that exposure to the stress of racism may increase the risk of dementia for Black Americans.

METHODS

The present study used 17 years of data from a sample of 255 Black Americans to investigate the extent to which exposure to racial discrimination predicts subsequent changes in serum Alzheimer's Disease Research Center (ADRC) biomarkers: serum phosphorylated tau181(p-tau181), neurofilament light (NfL), and glial fibrillary acidic protein (GFAP). We hypothesized that racial discrimination assessed during middle age would predict increases in these serum biomarkers as the participants aged into their 60s.

RESULTS

Our findings indicate that exposure to various forms of racial discrimination during a person's 40s and early 50s predicts an 11-year increase in both serum p-tau181 and NfL. Racial discrimination was not associated with subsequent levels of GFAP.

DISCUSSION

These findings suggest that racial discrimination in midlife may contribute to increased AD pathology and neurodegeneration later in life.

HIGHLIGHTS

A 17-year longitudinal study of Black Americans. Assessments of change in serum p-tau181, neurofilament light, and glial fibrillary acidic protein. Exposure to racial discrimination during middle age predicted increases in p-tau181 and neurofilament light. Education was positively related to both p-tau181 and exposure to racial discrimination.

Polygenic risk for schizophrenia, social dispositions, and pace of epigenetic aging: Results from the Young Finns Study

Schizophrenia is often regarded as a disorder of premature aging. We investigated (a) whether polygenic risk for schizophrenia (PRSsch ) relates to pace of epigenetic aging and (b) whether personal dispositions toward active and emotionally close relationships protect against accelerated epigenetic aging in individuals with high PRSsch . The sample came from the population-based Young Finns Study (n = 1348). Epigenetic aging was measured with DNA methylation aging algorithms such as AgeAccelHannum , EEAAHannum , IEAAHannum , IEAAHorvath , AgeAccelHorvath , AgeAccelPheno , AgeAccelGrim , and DunedinPACE. A PRSsch was calculated using summary statistics from the most comprehensive genome-wide association study of schizophrenia to date. Social dispositions were assessed in terms of extraversion, sociability, reward dependence, cooperativeness, and attachment security. We found that PRSsch did not have a statistically significant effect on any studied indicator of epigenetic aging. Instead, PRSsch had a significant interaction with reward dependence (p = 0.001-0.004), cooperation (p = 0.009-0.020), extraversion (p = 0.019-0.041), sociability (p = 0.003-0.016), and attachment security (p = 0.007-0.014) in predicting AgeAccelHannum , EEAAHannum , or IEAAHannum . Specifically, participants with high PRSsch appeared to display accelerated epigenetic aging at higher (vs. lower) levels of extraversion, sociability, attachment security, reward dependence, and cooperativeness. A rather opposite pattern was evident for those with low PRSsch . No such interactions were evident when predicting the other indicators of epigenetic aging. In conclusion, against our hypothesis, frequent social interactions may relate to accelerated epigenetic aging in individuals at risk for psychosis. We speculate that this may be explained by social-cognitive impairments (perceiving social situations as overwhelming or excessively arousing) or ending up in less supportive or deviant social groups.

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.