Prisoner of war status, posttraumatic stress disorder, and dementia in older veterans.

BACKGROUND: It is not known whether prisoners of war (POWs) are more likely to develop dementia independently of the effects of posttraumatic stress disorder (PTSD).

METHODS: We performed a retrospective cohort study in 182,879 U.S. veterans age 55 years and older, and examined associations between POW status and PTSD at baseline (October 1, 2000-September 30, 2003), and incident dementia during follow-up (October 1, 2003-September 30, 2012).

RESULTS: A total of 484 veterans (0.3%) reported being POWs, of whom 150 (31.0%) also had PTSD. After adjusting for demographics, medical and psychiatric comorbidities, period of service, and the competing risk of death, the risk of dementia was increased in veterans who were POWs only (hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.30-1.98) or had PTSD only (HR, 1.52; 95% CI, 1.41-1.64) and was greatest in veterans who were POWs and also had PTSD (HR, 2.24; 95% CI, 1.72-2.92).

CONCLUSIONS: POW status and PTSD increase risk of dementia in an independent, additive manner in older veterans.