Older veterans that experienced a traumatic brain injury (TBI) are 60 percent more likely to develop dementia than those who did not.

The recent study also found that veterans with a history of TBIs tended to get dementia two years earlier than those who did not, an American Academy of Neurology news release reported.

"These findings suggest that a history of TBI contributes risk for dementia in later life in veterans. If we assume that this relationship is causal, it seems likely that the same increased risk probably occurs with TBI in the civilian population as well," said study author Deborah E. Barnes, PhD, MPH, of the University of California, San Francisco and the San Francisco Veterans Affairs Medical Center and a member of the American Academy of Neurology.

The researchers looked at 188,784 veterans who were an average age of 68 at the start of the study. A total of 1,229 veterans had a TBI diagnosis at some point in their lives. After a seven year follow-up period 196 with TBI (16 percent) developed dementia compared with 18,255 (10 percent) without TBI.  After adjusting for other factors that increase the risk of dementia, the team determined that veterans with TBI were 60 percent more likely to develop the condition.

 "This study convincingly shows that mild trauma has a role in increasing the risk of dementia and sheds light on the more complex relationship between medical and psychiatric diseases with TBI in the development of the future risk of dementias. Neuroscientists must take a careful and comprehensive approach and avoid oversimplified claims of causality," Rodolfo Savica, MD, MSc, of the University of Utah School of Medicine in Salt Lake City, and a member of the American Academy of Neurology, who wrote an editorial accompanying the study, said in the news release.