APOE-ϵ4 Genotype is Associated with Elevated Post-Concussion Symptoms in Military Veterans with a Remote History of Mild Traumatic Brain Injury

Abstract

Objective: We evaluated the influence of the APOE-ϵ4 allele on post-concussive symptoms in military Veterans with a remote history of mild traumatic brain injury (mTBI). Method: Participants (N = 77) were administered neuropsychiatric measures, on average, approximately 5 years following their most recent mTBI and provided a DNA sample for APOE genotyping. Veterans were divided into two groups based on their ϵ4 status (n = 14 ϵ4+, n = 63 ϵ4-). The Neurobehavioral Symptom Inventory (NSI) was the primary outcome measure, from which a total score was derived, as well as three symptom clusters (somatic, cognitive, and affective). Results: ANCOVAs showed a significant main effect of ϵ4 genotype on the NSI total score and somatic symptom cluster after adjusting for posttraumatic stress symptoms and mTBI history (p =. 019-.028, ηp2 =. 064-.073), such that ϵ4+ Veterans endorsed significantly greater symptoms than ϵ4-Veterans. Conclusions: Our findings suggest that genetic risk may help to explain the poorer long-term outcomes often observed in this population.