The epidemiology of traumatic brain injury: a review.

PURPOSE Traumatic brain injury (TBI) not only has considerable morbidity and mortality, but it is a major cause of epilepsy. We wish to determine the frequency of TBI, special groups at risk for TBI, and mortality from TBI. METHODS We reviewed studies of TBI that are either population based or derived from definable catchment areas that allow determination of incidence, identification of risk groups, and mortality. We review methodology used in epidemiologic studies of TBI and try to distinguish this data from that of head injury not necessarily affecting the brain. We report epidemiologic characteristics of TBI, including incidence, differences by age, gender, race and ethnic group, and geographic variation, and mortality. RESULTS Population-based studies in the United States suggest that the incidence of TBI is between 180 and 250 per 100,000 population per year. Incidence may be higher in Europe and South Africa. There are groups at high risk for TBI. This includes males and individuals living in regions characterized by socioeconomic deprivation. There are selective age groups at risk for TBI. This includes the very young, adolescents and young adults, and the elderly. Mortality varies by severity but is high in those with severe injury and in the elderly. CONCLUSIONS TBI is a major public health problem as well as a major cause of epilepsy. If primary prevention is to be undertaken, we must understand the epidemiology of the condition. The primary causes of TBI vary by age, socioeconomic factors, and geographic region, so any planned interventions must be tailored accordingly.