Post-traumatic stress disorder and risk of dementia among members of a health care delivery system.

Introduction: Post-traumatic stress disorder (PTSD) is associated with an increased risk of dementia in male veterans, but little is known in females and civilians.

Methods: PTSD and comorbidities were abstracted from medical records from 1/1/1996 to 12/31/2001. Dementia incidence from 1/1/2002 to 12/31/2014 in 499,844 health care members aged 60+ years over an average of 8.2 years. Cox proportional hazard models were adjusted for age, demographics, and comorbidities.

Results: PTSD was associated with increased risk of dementia over an average of 8 years of follow-up (females: hazard ratio [HR] = 1.59, 95% confidence interval [CI] = 1.30-1.95; males: HR = 1.96, 95% CI = 1.51-2.55). There was a two-fold risk of dementia in those with both PTSD and depression (females: HR = 2.08; 95% CI = 1.66-2.59; males: HR = 2.06; 95% CI = 1.47-2.91) versus those without.

Discussion: PTSD was a risk factor for dementia in both sexes, with a heightened risk in those with comorbid depression.