116Dementia risk in individuals with lifetime major trauma and post-traumatic stress disorder (PTSD) symptoms

Background Increasing evidence suggests that stress may be a risk factor for dementia, however further investigation is required particularly in community-dwelling individuals. This study investigated whether lifetime major trauma with and without re-experiencing of PTSD symptoms is associated with dementia risk. Methods Participants were 1,700 community-dwelling men and women enrolled in the ESPRIT study of later-life neuropsychiatric disorders. Lifetime major trauma and PTSD were assessed using Watson’s PTSD Inventory. Cognitive function was measured using tests of global cognition, visual memory, verbal fluency, psychomotor speed and executive function. Fourteen-year incident dementia was diagnosed according to DSM-IV criteria. The association between lifetime trauma and cognition, as well as incident dementia was determined by multivariate logistic regression and Cox-proportional hazards regression, respectively. Results An unexpected, yet consistent finding was the association between lifetime major trauma without re-experiencing symptoms, and better baseline cognition (global OR: 0.67 [95% CI: 0.52-0.87], executive function OR: 0.69 [95% CI: 0.51-0.93]). Furthermore, lifetime trauma without re-experiencing symptoms was associated with a decreased risk of dementia (HR: 0.63, 95% CI: 0.44-0.91), particularly for females (HR: 0.49, 95% CI: 0.29-0.80). Conclusions Lifetime major trauma without re-experiencing symptoms may be protective for later-life cognitive function and could reduce dementia risk, especially in females. The mechanisms and moderating factors underlying these association requires further investigation. Key messages This study presents novel findings, and suggests that in some instances, experiencing traumatic events may be beneficial in later-life health.