A recent study of veterans with traumatic brain injuries (or TBI) are twice as likely to develop dementia later in life. The expansive study by the United States Military showed that traumatic brain injuries can be more harmful than previously thought. According to the CDC, a traumatic brain injury is “a disruption in the normal function of the brain that can be caused by a bump, blow or jolt to the head, or penetrating head injury.” Previous studies on the link between dementia and TBI showed a connection, however military researchers say this study provides conclusive evidence that traumatic brain injuries sharply increase a veteran’s risk for dementia later in life.
Further, researchers say the evidence shows that even a mild TBI – defined as one that does not cause the injured person to become unconscious – increases the risk of dementia. According to military statistics, between 15 and 20 percent of veterans who served in Iraq and Afghanistan suffered at least a mild TBI and almost half of all TBIs are characterized as either moderate or severe. The military said that the majority of minor TBI are caused by “exposure to a shock wave that follows an explosion.”
Scientists are unsure exactly why dementia rates increase with individuals who have suffered brain injuries. Some scientists believe that a TBI may trigger development of the “abnormal proteins” that cause Alzheimer’s disease. Other scientists say that a traumatic brain injury may just weaken the brain in a way that exposes it to more vulnerabilities. The author of the military study on veterans with TBI, Kristine Yaffe, concluded that “we need more work in this area” and all potential causes were merely theoretical at this point. The study, which tracked more than 350,000 veterans, will be published in JAMA Neurology next month.