According to researchers at Oxford University and Karolinska Institute in Stockholm, Sweden, survivors of traumatic brain injuries are three times more likely to die prematurely than the general population, often from suicide or fatal injuries.
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, said the study published in the journal JAMA Psychiatry.
Schumacher, 44, who remains in critical condition at a hospital in Grenoble, France, after suffering severe head injuries, has been in a medically induced, unconscious state for 18 days.
Researchers examined Swedish medical records going back 41 years covering 218,300 TBI survivors, 150,513 siblings of TBI survivors and over two 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 study leader Seena Fazel, a Wellcome Trust Senior Research Fellow at Oxford University's department of psychiatry.
The results show that TBI survivors who also have a history of substance abuse or psychiatric disorders are at highest risk of premature death, said the study.
This new finding offers key insight into the longer-term impact of TBI's on the brain and their effect on survival later in life.
"We hope that further research into understanding which parts of the brain are responsible would help improve future management programmes and reduce the potential for premature death," said Fazel.
Premature deaths were 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, added the study.
TBI survivors should be monitored carefully for signs of depression, substance abuse and other psychiatric disorders, which are all treatable conditions, it said.
Concussions, sometimes called mild TBIs, do not present with these symptoms and were analysed separately, said the study.