The epidemiology of traumatic brain injury.

OBJECTIVE: To describe the most recent estimates of the incidence and prevalence of traumatic brain injury (TBI) and review current issues related to measurement and use of these data.

DESIGN: State of the science literature for the United States and abroad was analyzed and issues were identified for (1) incidence of TBI, (2) prevalence of lifetime history of TBI, and (3) incidence and prevalence of disability associated with TBI.

RESULTS: The most recent estimates indicate that each year 235 000 Americans are hospitalized for nonfatal TBI, 1.1 million are treated in emergency departments, and 50 000 die. The northern Finland birth cohort found that 3.8% of the population had experienced at least 1 hospitalization due to TBI by 35 years of age. The Christchurch New Zealand birth cohort found that by 25 years of age 31.6% of the population had experienced at least 1 TBI, requiring medical attention (hospitalization, emergency department, or physician office). An estimated 43.3% of Americans have residual disability 1 year after hospitalization with TBI. [corrected] The most recent estimate of the prevalence of US civilian residents living with disability following hospitalization with TBI is 3.2 million.

CONCLUSION: Estimates of the incidence and prevalence of TBI are based on varying sources of data, methods of calculation, and assumptions. Informed users should be cognizant of the limitations of these estimates when determining their applicability.