A traumatic brain injury (TBI) triples the risk of a person dying before the age of 56, often as a result of violence or suicide, a study has found.
A TBI is a blow to the head that results in a skull fracture, internal bleeding, or loss of consciousness for more than an hour.
The link between traumatic brain injury and early death was discovered by scientists studying the Swedish medical records of 218,300 TBI survivors dating back 41 years.
Study leader Dr Seena Fazel, from Oxford University's Department of Psychiatry, said: "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.
"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."