Traumatic brain injury, posttraumatic stress disorder, and vascular risk are independently associated with white matter aging in Vietnam-Era veterans.

McGill, Makenna B.; Clark, Alexandra L.; Schnyer, David M.

Objective: Traumatic brain injury (TBI), mental health conditions (e.g., posttraumatic stress disorder [PTSD]), and vascular comorbidities (e.g., hypertension, diabetes) are highly prevalent in the Veteran population and may exacerbate age-related changes to cerebral white matter (WM). Our study examined (1) relationships between health conditions—TBI history, PTSD, and vascular risk—and cerebral WM micro- and macrostructure, and (2) associations between WM measures and cognition. Method: We analyzed diffusion tensor images from 183 older male Veterans (mean age = 69.18; SD = 3.61) with (n = 95) and without (n = 88) a history of TBI using tractography. Generalized linear models examined associations between health conditions and diffusion metrics. Total WM hyperintensity (WMH) volume was calculated from fluid-attenuated inversion recovery images. Robust regression examined associations between health conditions and WMH volume. Finally, elastic net regularized regression examined associations between WM measures and cognitive performance. Results: Veterans with and without TBI did not differ in severity of PTSD or vascular risk (p's >0.05). TBI history, PTSD, and vascular risk were independently associated with poorer WM microstructural organization (p's 2 = 0.034). Higher WMH volume predicted poorer processing speed (R 2 = 0.052). Conclusions: Relative to TBI history and PTSD, vascular risk may be more robustly associated with WM micro- and macrostructure. Furthermore, greater WMH burden is associated with poorer processing speed. Our study supports the importance of vascular health interventions in mitigating negative brain aging outcomes in Veterans.

DIFFUSION tensor imaging; COGNITIVE aging; POST-traumatic stress disorder; BRAIN injuries; VETERANS

Journal of the International Neuropsychological Society, 2024, Vol 30, Issue 10, p923

1355-6177

Academic Journal

10.1017/S1355617724000626