Key points from article :
Traumatic brain injury (TBI) can come from falling, contact sports, traffic accidents or violence.
Swedish register searched for all cases of brain trauma and dementia from 1964 to 2012.
TBI sufferers compared with people who did not suffer such head injuries.
Link with dementia was more frequent the more severe the injury.
Occurrence of early dementia is 200–400 times more frequent among professional boxers.
