When Anger Remains Unspoken: Anger and Accelerated Epigenetic Aging Among Stress-Exposed Black Americans

Racial Discrimination, Neural Connectivity, and Epigenetic Aging Among Black Women

Importance

Racial discrimination increases the risk of adverse brain health outcomes, potentially via neuroplastic changes in emotion processing networks. The involvement of deep brain regions (brainstem and midbrain) in these responses is unknown. Potential associations of racial discrimination with alterations in deep brain functional connectivity and accelerated epigenetic aging, a process that substantially increases vulnerability to health problems, are also unknown.

Objective

To examine associations of racial discrimination with brainstem and midbrain resting-state functional connectivity (RSFC) and DNA methylation age acceleration (DMAA) among Black women in the US.

Design, Setting, and Participants

This cohort study was conducted between January 1, 2012, and February 28, 2015, and included a community-based sample of Black women (aged ≥18 years) recruited as part of the Grady Trauma Project. Self-reported racial discrimination was examined in association with seed-to-voxel brain connectivity, including the locus coeruleus (LC), periaqueductal gray (PAG), and superior colliculus (SC); an index of DMAA (Horvath clock) was also evaluated. Posttraumatic stress disorder (PTSD), trauma exposure, and age were used as covariates in statistical models to isolate racial discrimination-related variance. Data analysis was conducted between January 10 and October 30, 2023.

Exposure

Varying levels of racial discrimination exposure, other trauma exposure, and posttraumatic stress disorder (PTSD).

Main Outcomes and Measures

Racial discrimination frequency was assessed with the Experiences of Discrimination Scale, other trauma exposure was evaluated with the Traumatic Events Inventory, and current PTSD was evaluated with the PTSD Symptom Scale. Seed-to-voxel functional connectivity analyses were conducted with LC, PAG, and SC seeds. To assess DMAA, the Methylation EPIC BeadChip assay (Illumina) was conducted with whole-blood samples from a subset of 49 participants.

Results

This study included 90 Black women, with a mean (SD) age of 38.5 (11.3) years. Greater racial discrimination was associated with greater left LC RSFC to the bilateral precuneus (a region within the default mode network implicated in rumination and reliving of past events; cluster size k = 228; t85 = 4.78; P < .001, false discovery rate-corrected). Significant indirect effects were observed for the left LC-precuneus RSFC on the association between racial discrimination and DMAA (β [SE] = 0.45 [0.16]; 95% CI, 0.12-0.77).

Conclusions and Relevance

In this study, more frequent racial discrimination was associated with proportionately greater RSFC of the LC to the precuneus, and these connectivity alterations were associated with DMAA. These findings suggest that racial discrimination contributes to accelerated biological aging via altered connectivity between the LC and default mode network, increasing vulnerability for brain health problems.

Associations of stress and stress-related psychiatric disorders with GrimAge acceleration: review and suggestions for future work

The notion of "biological aging" as distinct from chronological aging has been of increasing interest in psychiatry, and many studies have explored associations of stress and psychiatric illness with accelerated biological aging. The "epigenetic clocks" are one avenue of this research, wherein "biological age" is estimated using DNA methylation data from specific CpG dinucleotide sites within the human genome. Many iterations of the epigenetic clocks have been developed, but the GrimAge clock continues to stand out for its ability to predict morbidity and mortality. Several studies have now explored associations of stress, PTSD, and MDD with GrimAge acceleration (GrimAA). While stress, PTSD, and MDD are distinct psychiatric entities, they may share common mechanisms underlying accelerated biological aging. Yet, no one has offered a review of the evidence on associations of stress and stress-related psychopathology with GrimAA. In this review, we identify nine publications on associations of stress, PTSD, and MDD with GrimAA. We find that results are mixed both within and across each of these exposures. However, we also find that analytic methods - and specifically, the choice of covariates - vary widely between studies. To address this, we draw upon popular methods from the field of clinical epidemiology to offer (1) a systematic framework for covariate selection, and (2) an approach to results reporting that facilitates analytic consensus. Although covariate selection will differ by the research question, we encourage researchers to consider adjustment for tobacco, alcohol use, physical activity, race, sex, adult socioeconomic status, medical comorbidity, and blood cell composition.

Reduced epigenetic age in older adults who volunteer

BACKGROUND

Volunteering is associated with improved health and well-being outcomes, including a reduced risk of mortality. However, the biological mechanisms underlying the association between volunteering and healthy aging and longevity have not been well-established. We evaluated if volunteering was associated with reduced epigenetic age acceleration in older adults.

METHODS

We evaluated associations between volunteering and age acceleration, measured by 13 DNA methylation (DNAm) "epigenetic clocks" in 4011 older adults (M_age=69 years; SD_age=10 years) who participated in the Health and Retirement Study. We assessed 9 first-generation clocks (Horvath, Hannum, Horvath Skin, Lin, Garagnani, Vidalbralo, Weidner, Yang, and Bocklandt, which predict chronological age) and 4 second-generation clocks (Zhang, PhenoAge, GrimAge, and DunedinPoAm, which predict future disease or longevity). We quantified the total associations between volunteering and DNAm age acceleration as well as the extent to which these associations might be attributable to potential confounding by individual demographics (e.g., race), social demographics (e.g., income), health factors (e.g., diabetes), and health behaviors (e.g., smoking).

RESULTS

Volunteering was associated with reduced epigenetic age acceleration across 6 epigenetic clocks optimized for predicting health and longevity (False Discovery Rate [FDR] q < 0.0001 for epigenetic clocks: PhenoAge, GrimAge, DunedinPoAm, Zhang mortality, Yang mitotic; FDR q < 0.01: Hannum). These associations were mostly independent of demographic and health factors, but substantially attenuated after adjusting for health behaviors.

CONCLUSION

Volunteering was associated with reduced epigenetic age acceleration in 6 of 13 (mostly second-generation) epigenetic clocks. Results provide preliminary evidence that volunteering might provide health benefits through slower biological aging and implicate health behaviors as one potential mechanism of such effects.

Psychological and biological mechanisms linking trauma with cardiovascular disease risk

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, and experiences of psychological trauma have been associated with subsequent CVD onset. Identifying key pathways connecting trauma with CVD has the potential to inform more targeted screening and intervention efforts to offset elevated cardiovascular risk. In this narrative review, we summarize the evidence for key psychological and biological mechanisms linking experiences of trauma with CVD risk. Additionally, we describe various methodologies for measuring these mechanisms in an effort to inform future research related to potential pathways. With regard to mechanisms involving posttraumatic psychopathology, the vast majority of research on psychological distress after trauma and CVD has focused on posttraumatic stress disorder (PTSD), even though posttraumatic psychopathology can manifest in other ways as well. Substantial evidence suggests that PTSD predicts the onset of a range of cardiovascular outcomes in trauma-exposed men and women, yet more research is needed to better understand posttraumatic psychopathology more comprehensively and how it may relate to CVD. Further, dysregulation of numerous biological systems may occur after trauma and in the presence of posttraumatic psychopathology; these processes of immune system dysregulation and elevated inflammation, oxidative stress, mitochondrial dysfunction, renin-angiotensin system dysregulation, and accelerated biological aging may all contribute to subsequent cardiovascular risk, although more research on these pathways in the context of traumatic stress is needed. Given that many of these mechanisms are closely intertwined, future research using a systems biology approach may prove fruitful for elucidating how processes unfold to contribute to CVD after trauma.

Epigenetic clocks and their association with trajectories in perceived discrimination and depressive symptoms among US middle-aged and older adults

Background: Perceived discrimination may be associated with accelerated aging later in life, with depressive symptoms acting as potential mediator.

Methods: A nationally representative sample of older adults was used [Health and Retirement Study 2010–2016, Age: 50–100 y in 2016, N = 2,806, 55.6% female, 82.3% Non-Hispanic White (NHW)] to evaluate associations of perceived discrimination measures [Experience of discrimination or EOD; and Reasons for Perceived discrimination or RPD) and depressive symptoms (DEP)] with 13 DNAm-based measures of epigenetic aging. Group-based trajectory and four-way mediation analyses were used.

Results: Overall, and mostly among female and NHW participants, greater RPD in 2010–2012 had a significant adverse total effect on epigenetic aging [2016: DNAm GrimAge, DunedinPoAm38 (MPOA), Levine (PhenoAge) and Horvath 2], with 20–50% of this effect being explained by a pure indirect effect through DEP in 2014–2016. Among females, sustained elevated DEP (2010–2016) was associated with greater LIN DNAm age (β ± SE: +1.506 ± 0.559, p = 0.009, reduced model), patterns observed for elevated DEP (high vs. low) for GrimAge and MPOA DNAm markers. Overall and in White adults, the relationship of the Levine clock with perceived discrimination in general (both EOD and RPD) was mediated through elevated DEP.

Conclusions: Sustained elevations in DEP and RPD were associated with select biological aging measures, consistently among women and White adults, with DEP acting as mediator in several RPD-EPICLOCK associations.

Association between racial/ethnic discrimination and pubertal development in early adolescence

Racial health disparities in the United States are a major concern, with Black or African Americans experiencing more morbidity and mortality at earlier ages compared to White Americans. More data is needed on the biological underpinnings of this phenomenon. One potential explanation for racial health disparities is that of accelerated aging, which is associated with increased stress exposure. Black Americans face disproportionate levels of environmental stress, specifically racial/ethnic discrimination. Here we investigated associations between self-reported experiences of discrimination and pubertal development (PD) in a diverse sample of young American adolescents (N = 11,235, mean age 10.9 years, 20.5% Black participants) from the Adolescent Brain Cognitive Development (ABCD) Study. Compared to their non-Black counterparts, Black youth experienced more racial/ethnic discrimination in the past year (10.4% vs 3.1%) and had a greater likelihood of being in late/post-pubertal status (3.6% vs 1.5% in boys, 21.3% vs 11.4% in girls). In both sexes, multivariable regression models run in the full sample revealed a cross-sectional association of experiences of racial/ethnic discrimination with pubertal development (boys: standardized beta [β]=0.123, P < .001; girls: β = 0.110, P < .001) covarying for demographics, BMI, and dietary habits. Associations remained significant when controlling for multiple other environmental confounders including other forms of (non-racial/ethnic) discrimination and other environmental adversities including poverty and negative life events, and when using parent-reported assessment of pubertal development. Furthermore, racial/ethnic discrimination was associated with elevated estradiol levels in girls (β = 0.057, P = .002). Findings suggest an association between experiences of discrimination and pubertal development that is independent of multiple environmental stressors. Future longitudinal studies are warranted to establish causal mechanism.