A TBI is a blow to the head that leads to a skull fracture, internal bleeding, loss of consciousness for longer than an hour, or a combination of these symptoms.
For the study, researchers examined medical records going back 41 years covering 218,300 TBI survivors. They also looked at the records of 150,513 siblings of TBI survivors and more than 2 million control cases matched by sex and age from the general population.
“We found that people who survive six months after TBI remain three times more likely to die prematurely than the control population and 2.6 times more likely to die than unaffected siblings,” said Dr. Seena Fazel, a Wellcome Trust Senior Research Fellow in Oxford University’s Department of Psychiatry.
“Looking at siblings who did not suffer TBIs allows us to control for genetic factors and early upbringing, so it is striking to see that the effect remains strong even after controlling for these.”
The findings also show that TBI survivors who have a history of substance abuse or psychiatric disorders are at the highest risk of premature death, which was defined as before age 56.
The main causes of premature death in TBI survivors are suicide and fatal injuries, such as car accidents and falls, the researchers noted.
“TBI survivors are more than twice as likely to kill themselves as unaffected siblings, many of whom were diagnosed with psychiatric disorders after their TBI,” said Fazel. “Current guidelines do not recommend assessments of mental health or suicide risk in TBI patients, instead focusing on short-term survival.
“Looking at these findings, it may make more sense to treat some TBI patients as suffering from a chronic problem requiring longer term management, just like epilepsy or diabetes. TBI survivors should be monitored carefully for signs of depression, substance abuse and other psychiatric disorders, which are all treatable conditions.’
The exact reasons for the increased risk of premature death are unknown, but may involve damage to the parts of the brain responsible for judgment, decision-making and risk taking, the researchers postulate.
“This study highlights the important and as-yet unanswered question of why TBI survivors are more likely to die young, but it may be that serious brain trauma has lasting effects on people’s judgment,” said Fazel.
“People who have survived the acute effects of TBI should be more informed about these risks and how to reduce their impact.”
The researchers found that even concussions, which are relatively minor brain injuries, had a significant impact on early mortality. People who had suffered a concussion were found to be twice as likely to die prematurely, with suicide and fatal injuries as the main causes of death for them as well.
This raises issues surrounding concussions in a wide range of sports, from American football, rugby and soccer to baseball and cricket, the researchers noted.
The study was published in the journal JAMA Psychiatry.
Source: University of Oxford