Background
Metabolic syndrome (MetS), defined by a constellation of cardiometabolic pathologies, is highly prevalent among veterans, especially those with posttraumatic stress disorder (PTSD), and poses a major risk for adverse health outcomes, including neurodegeneration and mortality. Given this, we evaluated: (a) the association between MetS and neural integrity, indexed by cortical thickness; (b) the relationship between PTSD and MetS; and (c) if PTSD was associated with cortical thickness indirectly through MetS.
Methods
The sample consisted of 346 US military veterans (89.3% male; 71.4% white) who deployed to Iraq and/or Afghanistan. Neuroimaging data were available for 274 participants.
Results
In whole-brain analyses, MetS was negatively associated with cortical thickness in 2 left and 4 right hemisphere regions: (a) bilateral temporal lobe, including temporal pole, fusiform gyrus, and insula, and extending into occipital cortex (left hemisphere) and orbitofrontal cortex (right hemisphere); (b) bilateral precuneus, posterior cingulate, calcarine, and occipital-parietal cortex; and (c) right rostral anterior cingulate cortex and central sulcus/postcentral gyrus. Path models showed that PTSD predicted MetS (β = .19, p < .001), which, in turn, was associated with reduced cortical thickness (βs from −.29 to – .43, all p <.001).
Conclusions
Results from this young veteran sample provide evidence that PTSD confers risk for cardiometabolic pathology and neurodegeneration and raise concern that this cohort may be aging pre-maturely and at risk for substantial medical and cognitive decline. This highlights the need to identify the molecular mechanisms linking PTSD to MetS and for effective interventions to reduce PTSD-related health comorbidities.