With weeks having passed after researchers suggested that even mild traumatic brain injuries (TBIs) could result in a higher risk of Parkinson's disease, a second study involving U.S. veterans is now hinting that these brain injuries, minor as they are, have the potential of increasing the risk of dementia.
According to a report from the Los Angeles Times, it had long been established that moderate and severe TBIs were associated with a higher risk of dementia and Alzheimer's disease, and a higher chance of developing either condition early. At the time of those studies, it was still unclear if mild TBIs increased the risk of those conditions. But the new study, which was published this week in the journal JAMA Neurology, suggests that even milder forms of traumatic brain injuries could have more serious consequences for veterans years down the line.
The researchers took a look at the medical records belonging to more than 350,000 veterans who previously fought in Iraq and Afghanistan, and determined that male and female veterans who suffered at least one mild TBI had more than double the risk of developing dementia after retirement, as compared to veterans who didn't suffer any brain injuries. This was based on information collected from two government databases, which identified close to 180,000 patients who were diagnosed by the Veterans Health Administration (VHA) with mild to severe traumatic brain injuries between 2001 and 2014,
After isolating the TBI cases found in the databases, the researchers matched the veterans with counterparts who also had records with the VHA, but were not diagnosed with any form of TBI. About 6.1 percent of the veterans in the TBI group suffered from dementia within an average of 3.6 years from the injury, while only 2.6 percent of those in the non-TBI control group developed the condition within an average span of 4.8 years. The researchers then adjusted for different variables, such as age, psychiatric conditions, and medical history, to determine that those who suffered from mild TBIs were at least 2.36 times more likely to develop dementia than the veterans in the control group, with the risk varying depending on whether the person lost consciousness or not following the injury.
Out of the injured veterans identified from the government databases, about 10 percent of the veterans suffered from mild TBIs and did not lose consciousness after being injured, while another 13 percent lost consciousness for 30 minutes or less after having a mild TBI. Thirty-one percent of these veterans were diagnosed with mild TBIs, with medical records not specifying whether they lost consciousness or not. The remaining 46 percent had either moderate or severe TBIs.