Incidence
A survey in the USA found that TBI sufferers tend to be male (78%), and that 39% were between the ages of 16-25 (the mean age was 34 years). More specifically age appears to be related to aetiology of injury. In other words, in those below the age of 25, motor vehicle crashes were the primary cause of injury; violence related injuries were most frequently found in the 36-45 age group; pedestrian accidents most frequently occurred in those above 65 and 76% of the falls happened to those above 56. 76% of those wearing seat belts and 84% of those in motorcycle crashes were not wearing helmets at the time of injury. 51% of those included in the database had elevated blood alcohol levels at the time of injury.