Post-traumatic stress disorder and risk of dementia among U.S. veterans

Abstract

Post-traumatic stress disorder (PTSD) is highly prevalent among veterans returning from combat and may impair cognitive function. Our goal was to determine if PTSD was associated with risk of developing dementia among older veterans in the US receiving treatment in veterans’ medical centers. Using data from the Department of Veterans Affairs (VA) National Patient Care Database, we conducted a stratified retrospective cohort study of 181,093 veterans aged ≥ 55 years without dementia from 1997-2000 (53,155 veterans diagnosed with PTSD and 127,938 veterans without PTSD). During the follow-up period from 2001 through 2007, we ascertained newly diagnosed dementia or cognitive impairment from ICD-9 codes. The mean baseline age of the veterans was 68.8 years and 97% were male. Veterans with PTSD had a 7-year cumulative incident dementia rate of 14.4% whereas those without PTSD had a rate of 8.1% (p<0.001). In multivariable models using age as the time scale and adjusting for demographics, medical and psychiatric comorbidities, PTSD patients were still nearly twice as likely to develop incident dementia (HR = 1.93, 95% CI 1.86-2.00). Results were similar when we excluded those with a history of traumatic brain injury, substance abuse or depression. We found that in a predominately male veteran cohort, those diagnosed with PTSD were at a nearly two-fold higher risk of developing dementia compared to veterans without PTSD. Mechanisms linking these important disorders need to be identified with the hope of finding ways to reduce the increased risk of dementia associated with PTSD.