Study Suggests PTSD, Brain Injury Can Increase Impact of Alzheimer's-Linked Gene Variant

A large-scale study has found that head trauma and post-traumatic stress disorder (PTSD) affect genetic risk for Alzheimer's disease. While PTSD and traumatic brain injury (TBI) are known to increase dementia risk, some research has suggested that the epsilon 4 variant of apolipoprotein E (APOE) — the strongest Alzheimer's disease genetic risk factor — might modify that risk. In Alzheimer's & Dementia: The Journal of the Alzheimer's Association this week, researchers from the VA Boston Healthcare System used data from the US Department of Veterans Affairs' Million Veteran Program to determine the effects of PTSD, TBI, and APOE epsilon 4 on Alzheimer's disease and related dementias in veteran cohorts of European and African ancestry. They found higher rates of dementias in veterans with PTSD and TBI, as well as in those with APOE epsilon 4. Notably, they also discovered that the effects of PTSD and TBI on dementia rates was greater in APOE epsilon 4 carriers. The findings, the study's authors write, indicate that PTSD and TBI history "can be an important component of genetic dementia risk assessment and targeting early intervention."