Developmental timing of index trauma exposure and accelerated epigenetic aging in United States military veterans.

Trauma exposure has been linked to accelerated GrimAge, an epigenetic biomarker of premature morbidity and mortality. Building on this evidence, the present study examined whether the type and timing of index trauma exposure are differentially associated with accelerated GrimAge. Participants were 873 European American male United States military Veterans from the National Health and Resilience in Veterans Study. We investigated associations between self-reported age at index trauma, index trauma type (interpersonal violence, non-interpersonal trauma, or loss/instability/other), and accelerated GrimAge, operationalized as GrimAge exceeding chronological age by five or more years. Results revealed that interpersonal violence was associated with three-fold greater odds of accelerated GrimAge compared to other trauma types. Age at index trauma was not independently associated with accelerated GrimAge. However, we observed a significant interaction between trauma type and its developmental timing, even after adjusting for index trauma recency, cumulative trauma burden, and other potential confounders. Specifically, Veterans who were older at the time of exposure to interpersonal violence or trauma involving loss or instability had higher odds of accelerated GrimAge. In contrast, exposure to non-interpersonal trauma was more strongly associated with accelerated GrimAge when it occurred at younger ages. These results indicate that trauma type and timing jointly influence epigenetic aging in Veterans, highlighting the need for tailored interventions that address specific trauma characteristics to reduce associated long-term health risks in this population.