VIENNA — Post-traumatic stress disorder nearly doubled the risk of later dementia in large cohort of male veterans, a retrospective study has determined.
The finding points to the importance of close follow-up for veterans—or any patient—with symptoms of the stress-induced disorder, Dr. Kristine Yaffe said at the International Conference on Alzheimer's Disease. “It's critical to follow patients with PTSD and evaluate them early for dementia,” said Dr. Yaffe, director of the Memory Disorders Clinic at the San Francisco Veterans Administration Medical Center.
Dr. Yaffe studied the incidence of dementia in a retrospective cohort of 183,000 veterans in the Department of Veterans Affairs National Patient Care Database who did not have dementia at baseline enrollment (1997-2000). Most of the subjects (97%) were men; their mean age at baseline was 69 years. PTSD had been diagnosed in 53,155 of the subjects.
During a follow-up period from 2001 to 2007, the cumulative incidence of new-onset dementia was 11% for those veterans with PTSD and 7% for those without PTSD—a significant difference. The results did not change even when Dr. Yaffe excluded subjects with a history of traumatic brain injury, substance abuse, or depression.
“Even after adjusting for demographics and medical and psychiatric comorbidities, PTSD patients in this study were still nearly twice as likely to develop incident dementia—hazard ratio 1.8—than veterans without PTSD,” she said at the meeting, which was sponsored by the Alzheimer's Association.
PTSD was significantly associated with all four subtypes types of dementia that Dr. Yaffe examined, conferring a 70% increased risk of Alzheimer's disease, a doubled risk of senile dementia, a 70% increased risk of vascular dementia, and an 80% increased risk of nonspecific dementia.
She could not speculate on the nature of the connection between PTSD and dementia, saying that more research is necessary. “With that knowledge, we may be able to find ways to reduce the increased risk of dementia associated with PTSD.” However, she noted that other studies have confirmed that the disorder is associated with decreases in hippocampal volume, cognitive dysfunction, and alteration of the hypothalamic-pituitary-adrenal axis.
Dr. Yaffe said she did not have any potential conflicts of interest with regard to the study.