Effects of Posttraumatic Stress Disorder and Metabolic Syndrome on Cognitive Aging in Veterans

With the influx of veterans entering older adulthood, it is increasingly important to understand risk factors for cognitive decline. Posttraumatic stress disorder (PTSD) and the metabolic syndrome (MetS) are highly prevalent in older veterans. Although both increase risk for cognitive decline and often co-occur, it is unclear how they may interact to negatively impact cognition. The aim of this cross-sectional study was to investigate associations among PTSD, MetS, and cognitive function in older veterans. We hypothesized that co-occurring PTSD and MetS would be associated with worse cognitive performance than seen in either illness alone.

Participants completed cognitive testing to assess processing speed, verbal memory, and executive function. Data from 204 male veterans aged 55-89 were analyzed with the use of hierarchical multiple regression models.

Veterans with MetS demonstrated poorer performance on tasks of executive function (response inhibition and cognitive set shifting) and immediate verbal memory regardless of PTSD status. There was an interaction between MetS and PTSD on delayed verbal memory, suggesting that the negative impact of MetS on verbal memory was only significant for veterans not classified as having PTSD.

This is the first study to examine the impact of comorbid PTSD and MetS on cognition. The results suggest that MetS is associated with poorer verbal learning and executive functioning independent of PTSD. We discuss the necessity of monitoring cerebrovascular risk factors and providing early behavioral and/or pharmaceutical interventions to lessen the risk of cognitive decline in older age.