Accelerated DNA Methylation Age: Associations With Posttraumatic Stress Disorder and Mortality

Posttraumatic Stress Disorder Symptoms, Temperament, and the Pathway to Cellular Senescence

Traumatic stress is thought to be associated with shortened telomere length (TL) in leukocytes, an age-related marker of increased risk for cellular senescence, although findings thus far have been mixed. We assessed associations between posttraumatic stress disorder (PTSD) symptom severity, temperament, and TL in a sample of 453 White, non-Hispanic, middle-aged, trauma-exposed male and female veterans and civilians. Given that prior research has suggested an association between PTSD and accelerated cellular age, we also examined associations between TL and an index of accelerated cellular age derived from DNA methylation data (DNAm age). Analyses revealed that, controlling for chronological age, PTSD was not directly associated with TL but rather this association was moderated by age, β = -.14, p = .003, ΔR2 = .02. Specifically, PTSD severity evidenced a stronger negative association with TL among relatively older participants (≥ 55 years of age). In a subset of veterans with data pertaining to temperament (n = 150), positive emotionality, and, specifically, a drive toward achievement, β = .26, p = .002, ΔR2 = .06, were positively associated with TL. There was no evidence of an association between age-adjusted TL and accelerated DNAm age. Collectively, these results indicate that older adults may be more vulnerable to the negative health effects of PTSD but that traits such as achievement, resilience, and psychological hardiness may be protective. These findings underscore the importance of identifying reliable biomarkers of cellular aging and senescence and of determining the biological mechanisms that contribute to stress-related disease and decline.

Traumatic stress and accelerated DNA methylation age: A meta-analysis

BACKGROUND

Recent studies examining the association between posttraumatic stress disorder (PTSD) and accelerated aging, as defined by DNA methylation-based estimates of cellular age that exceed chronological age, have yielded mixed results.

METHODS

We conducted a meta-analysis of trauma exposure and PTSD diagnosis and symptom severity in association with accelerated DNA methylation age using data from 9 cohorts contributing to the Psychiatric Genomics Consortium PTSD Epigenetics Workgroup (combined N = 2186). Associations between demographic and cellular variables and accelerated DNA methylation age were also examined, as was the moderating influence of demographic variables.

RESULTS

Meta-analysis of regression coefficients from contributing cohorts revealed that childhood trauma exposure (when measured with the Childhood Trauma Questionnaire) and lifetime PTSD severity evidenced significant, albeit small, meta-analytic associations with accelerated DNA methylation age (ps = 0.028 and 0.016, respectively). Sex, CD4T cell proportions, and natural killer cell proportions were also significantly associated with accelerated DNA methylation age (all ps < 0.02). PTSD diagnosis and lifetime trauma exposure were not associated with advanced DNA methylation age. There was no evidence of moderation of the trauma or PTSD variables by demographic factors.

CONCLUSIONS

Results suggest that traumatic stress is associated with advanced epigenetic age and raise the possibility that cells integral to immune system maintenance and responsivity play a role in this. This study highlights the need for additional research into the biological mechanisms linking traumatic stress to accelerated DNA methylation age and the importance of furthering our understanding of the neurobiological and health consequences of PTSD.

Accelerated DNA methylation aging and increased resilience in veterans: The biological cost for soldiering on

Accelerated epigenetic aging, the difference between the DNA methylation-predicted age (DNAm age) and the chronological age, is associated with a myriad of diseases. This study investigates the relationship between epigenetic aging and risk and protective factors of PTSD. Genome-wide DNA methylation analysis was performed in 211 individuals including combat-exposed Australian veterans (discovery cohort, n = 96 males) and trauma-exposed civilian males from the Grady Trauma Project (replication cohort, n = 115 males). Primary measures included the Clinician Administered PTSD Scale for DSM-5 and the Connor-Davidson Resilience Scale (CD-RISC). DNAm age prediction was performed using the validated epigenetic clock calculator. Veterans with PTSD had increased PTSD symptom severity (P-value = 3.75 × 10-34) and lower CD-RISC scores (P-value = 7.5 × 10-8) than veterans without PTSD. DNAm age was significantly correlated with the chronological age (P-value = 3.3 × 10-6), but DNAm age acceleration was not different between the PTSD and non-PTSD groups (P-value = 0.24). Evaluating potential protective factors, we found that DNAm age acceleration was significantly associated with CD-RISC resilience scores in veterans with PTSD, these results remained significant after multiple testing correction (P-value = 0.023; r = 0.32). This finding was also replicated in an independent trauma-exposed civilian cohort (P-value = 0.02; r = 0.23). Post-hoc factor analyses revealed that this association was likely driven by "self-efficacy" items within the CD-RISC (P-value = 0.015; r = 0.35). These results suggest that among individuals already suffering from PTSD, some aspects of increased resilience might come at a biological cost.

Traumatic Stress and Accelerated Cellular Aging: From Epigenetics to Cardiometabolic Disease

PURPOSE OF REVIEW

The aim of this paper is to review the recent literature on traumatic stress-related accelerated aging, including a focus on cellular mechanisms and biomarkers of cellular aging and on the clinical manifestations of accelerated biological aging.

RECENT FINDINGS

Multiple lines of research converge to suggest that PTSD is associated with accelerated aging in the epigenome, and the immune and inflammation systems, and this may be reflected in premature onset of cardiometabolic and cardiovascular disease. The current state of research paves the way for future work focused on identifying the peripheral and central biological mechanisms linking traumatic stress to accelerated biological aging and medical morbidity, with an emphasis on processes involved in inflammation, immune functioning, oxidative stress, autonomic arousal, and stress response. Ultimately, such work could help reduce the pace of biological aging and improve health and wellness.