Male veterans with posttraumatic stress disorder appear to be nearly twice as likely to develop dementia as those who do not have PTSD, a study has shown.
The reason for this association is not yet known, nor is it clear whether treatment of PTSD reduces dementia risk. Until more is understood about this newly identified link, it is critical that all patients with PTSD, especially those of advanced age, be followed to screen for cognitive impairment, said Dr. Kristine Yaffe of the University of California, San Francisco, and her associates.
To their knowledge this is the first study of its kind, despite observational reports that older patients with PTSD have been found to show greater declines in cognitive performance than control subjects.
“Given that PTSD symptoms often continue late in life and that alterations in the hypothalamic-pituitary-adrenal axis often accompany PTSD, and these in turn may be associated with dementia, there is reason to believe that PTSD might be associated with accelerated brain aging,” they said.
Dr. Yaffe and her colleagues performed a retrospective cohort study involving 181,093 veterans (96% males), aged 55 and older, who received their medical treatment at VA hospitals nationwide. A total of 53,155 of these patients had received a diagnosis of PTSD, while the remainder had no PTSD.
At baseline, the veterans had a mean age of 69 years and were followed for a mean of 7 years to track the development of incident dementia. This included senile dementias, vascular dementia, Alzheimer's disease, frontotemporal dementia, Lewy body dementia, and dementia “not otherwise specified.”
Patients with PTSD were nearly twice as likely to develop dementia during follow-up as were those without PTSD, with a hazard ratio of 1.77. The cumulative incidence of dementia was about 11% with PTSD, compared with approximately 7% without it, Dr. Yaffe and her associates said (Arch. Gen. Psychiatry 2010;67:608-13).
The link was strong across all dementia subtypes, and it persisted when subjects with diagnoses of clinical depression, substance abuse, or head injury were excluded from the analysis.
This study was limited in that it enrolled male veterans primarily. The study was funded by the U.S. Department of Defense and the National Institute on Aging. Dr. Yaffe and her associates reported ties to Novartis, Zelos Therapeutics, Tethys Bioscience, NPS Pharmaceuticals, Actelion Pharmaceuticals, Sanofi-Aventis, Takeda, the Chatham Institute, and the Pri-Med Institute.