By analyzing the data of thousands of U.S. veterans, researchers have found that people who have mild traumatic brain injury even without loss of consciousness still have more than twice the risk of developing dementia compared with people who do not have these injuries.

Large Study Of US Veterans

Jack Tsao, from Memphis Veterans Affairs Medical Center, and colleagues looked at the data of nearly 358,000 veterans, most of whom were male. Half of these veterans were diagnosed with brain injuries and the other half did not have history of brain injury.

The researchers found that the veterans with mild traumatic brain injury who did not lose consciousness had 2.4 times increased risk of developing dementia than their counterparts without brain injury.

For those who had lost consciousness, the likelihood of getting diagnosed with dementia was 2.5 times higher. Moderate to severe brain injuries, on the other hand, were linked to 3.77 times higher risk.

Researchers also found that dementia diagnosis tend to occur about 1.5 years earlier in individuals with brain injuries compared with those without brain injuries.

"We observed a dose-response association between TBI severity and dementia diagnosis," the researchers wrote in their study, which was published in JAMA Neurology on May 7.

"Even mild TBI without loss of consciousness was associated with more than a 2-fold increase in the risk of dementia diagnosis after adjusting for demographic factors and medical and psychiatric comorbidities."

US Veterans At Higher Risk Of Dementia

In an editorial, Ramon Diaz-Arrastia, from the University of Pennsylvania in Philadelphia, and Kimbra Kenney, from the Uniformed Services University of the Health Services in Bethesda, wrote that the large study provides the best information to date that show U.S. veterans face higher risk of dementia as a result of injury they sustain while serving the country. U.S. soldiers are also at higher risk for post-traumatic stress disorder (PTSD) because of their line of work.

"The young mean age of veterans in this study (50 years) raises concerns that this problem will increase as TBI-exposed veterans age," Diaz-Arrastia and Kenney wrote. "Substantial investments in clinical care and neuroscience research will be needed in the next decades to fulfill society's obligations to those who have served our country."

Tsai said that there is no way to reduce dementia risk after a brain injury but getting the proper treatment is crucial. Rest and taking precautionary measures to avoid another injury can also help with immediate clinical recovery.