Epidemiology of Traumatic Brain Injury
Of all types of injury, those to the brain are among the most likely to result in death or permanent disability. Estimates of traumatic brain injury (TBI) incidence, severity, and cost reflect the enormous losses to individuals, their families, and society from these injuries. These data demonstrate a critical need for more effective ways to prevent brain injuries and care for those who are injured.
Highlights
Incidence of traumatic brain injury (TBI). Using national data for 1995-1996, the CDC estimates that TBIs have this impact in the United States each year:
- 1 million people are treated and released from hospital emergency departments
- 230,000 people are hospitalized and survive
- 50,000 people die
TBI incidence rate, risk factors, and causes. Using preliminary hospitalization and mortality data collected from 12 states (Alaska, Arizona, Sacramento County [California], Colorado, Louisiana, Maryland, Missouri, New York, Oklahoma, Rhode Island, South Carolina, and Utah) during 1995-1996, CDC finds the following:
- The average TBI incidence rate (combined hospitalization and mortality rate) is 95 per 100,000 population. Twenty-two percent of people who have a TBI die from their injuries. The risk of having a TBI is especially high among adolescents, young adults, and people older than 75 years of age.
- For persons of all ages, the risk of TBI among males is twice the risk among females.
- The leading causes of TBI are motor vehicle crashes, violence, and falls. Nearly two-thirds of firearm-related TBIs are classified as suicidal in intent.
- The leading causes of TBI vary by age: falls are the leading cause of TBI among persons aged 65 years and older, whereas transportation leads among persons aged 5 to 64 years.
- The outcome of these injuries varies greatly depending on the cause: 91% of firearm-related TBIs resulted in death, but only 11% of fall-related TBIs are fatal.
Incidence and prevalence of TBI-related disability. Based on national TBI incidence data and preliminary data from the Colorado Traumatic Brain Injury Registry that describe TBI-related disability in 1996-1997, CDC estimates the following:
- Each year more than 80,000 Americans survive a hospitalization for traumatic brain injury but are discharged with TBI-related disabilities.
- 5.3 million Americans are living today with a TBI-related disability.
Note: The preliminary estimates described above are derived from provisional data that are subject to change, pending receipt of additional data. Therefore, the information contained in this outline should not be published without approval from the Centers for Disease Control and Prevention.
Traumatic Brain Injury Incidence: Morbidity and Mortality
There are several published epidemiologic studies of TBI-related hospitalizations and deaths in the U.S. Kraus has reviewed some of these studies in detail.6 Recent data suggest a decline in rates of hospitalization for less severe TBI, possibly due to changes in hospital admission criteria.2 The lower TBI incidence rate seen today may be due in part to a real decline in brain injuries but also appear to be an artifact of counting methods which capture only hospitalized and fatal cases.
Location of Study Year(s) Annual Rate of TBI per 100,000 Population
Olmstead County, Minnesota 1934-74 [193]
U.S. 1974 [200]
San Diego, California 1978 [294]
North Central Virginia 1978 [175]
Rhode Island 1979-80 [249]
Chicago, Illinois 1980 [367]
Bronx, New York City, New York 1980 [249]
San Diego County, California1 1981 [180]
Maryland 1986 [132]
Utah 1990-92 [106]
Colorado, Missouri, Oklahoma, Utah 1990-93 [103]
Colorado18 1991-92 [101]
Seven states (AZ, CO, MN, MO, NY excluding NYC, OK, SC) 1994 [92]
Traumatic Brain Injury Mortality: Causes and Trends
There was a 22% decline in the TBI-related death rate from 24.6/100,000 U.S. residents in 1979 to 19.3/100,000 in 1992. Firearm-related rates increased 13% from 1984 through 1992, undermining a 25% decline in motor vehicle-related rates for the same period. Firearms surpassed motor vehicles as the largest single cause of death associated with traumatic brain injury in the United States in 1990. These data highlight the success of efforts to prevent traumatic brain injury due to motor vehicles and failure to prevent such injuries due to firearms. The increasing importance of penetrating injury has important implications for research, treatment, and prevention of traumatic brain injury in the United States.
Populations at Risk, Outcome and Cost
Populations at Risk
A number of studies have shown that males are about twice as likely to incur TBI as females. Most studies indicate that the highest rates of these injuries are found in persons 15-24 years of age. Persons under the age of 5 or over the age of 75 are also at high risk.
Outcome
Each year more than 50,000 Americans die following traumatic brain injuries.3 Each year an estimated 80,000 Americans survive a hospitalization for traumatic brain injury but are discharged with TBI-related disabilities. An estimated 5.3 million Americans are living today with a TBI-related disability.
There are many kinds of impairments that may occur as a result of TBI. These injuries may impair:
- cognition -- concentration, memory, judgment, and mood
- movement abilities -- strength, coordination, and balance
- sensation -- tactile sensation and special senses such as vision
- TBI sometimes results in seizure disorders (epilepsy). About 1 percent of persons with severe TBI survive in a state of persisting unconsciousness.
Cost
There is no way to describe fully the human costs of traumatic brain injury: the burdens borne by those who are injured and their families.
Only a few analyses of the monetary costs of these injuries are available, including the following estimate (lifetime cost of all brain injuries occurring in the United States in 1985):
Direct annual expenditures: $4.5 billion
Indirect annual costs: $33.3 billion
Total costs: $37.8 billion
Traumatic Brain Injury as a Public Health Problem
A large number of people experience traumatic brain injury each year, often with severe consequences. This is a public health problem that requires:
Ongoing surveillance to follow trends in the incidence, risk factors, causes, and outcomes of these injuries. To promote TBI surveillance efforts, the National Center for Injury Prevention and Control (NCIPC): developed Guidelines for the Surveillance of Central Nervous System Injury, a publication that sets forth standards and recommendations to improve coordination of central nervous system injury surveillance.22 The surveillance standards provide case definitions for traumatic brain injury and spinal cord injury and a list of defined data elements to be collected for each case of injury. Provided funding to Alaska, Arkansas, Arizona, California, Colorado, Louisiana, Maryland, Minnesota, Missouri, Nebraska, New York, Oklahoma, Rhode Island, South Carolina, and Utah to enhance current traumatic brain injury surveillance by using the standards defined in the Guidelines for the Surveillance of Central Nervous System Injury. These states contribute data to a multi-state surveillance system maintained by the NCIPC.
The development of effective, science-based strategies to prevent the occurrence of these injuries. In collaboration with other federal and state agencies, the National Center for Injury Prevention and Control supports programs for the primary prevention of motor vehicle-related injuries, other unintentional injuries, and violence-related injuries.
The development of more effective strategies to improve the outcomes of these injuries and minimize disability among those injured. The National Center for Injury Prevention and Control: provides funding to the Colorado Department of Public Health and the Environment (in collaboration with Craig Hospital) and the South Carolina Department of Health and Environmental Control (in collaboration with the University of South Carolina School of Medicine) to develop population-based follow-up registries of persons who have sustained traumatic brain injury. This project will determine the burden of disabilities, monitor trends in disabilities, identify subgroups of people with traumatic brain injury at highest risk of disability, and determine service utilization and barriers to service access. Developed Facts about Concussion and Brain Injury to address the lack of information on the symptoms, sequelae and treatment of less severe TBI. This booklet explains what can happen after a concussion, how to get better, and where to go for more information and help when needed. Funds cooperative agreements for Statewide Traumatic Brain Injury Surveillance Programs created the document, Traumatic Brain Injury in the United States: A Report to Congress, summarizing current knowledge about the incidence, causes, severity, associated disabilities, and prevalence of TBI.
References
Guerrero J, Thurman DJ, Sniezek JE. Emergency department visits association with traumatic brain injury: United States, 1995-1996. Brain Injury, 2000; 14(2):181-6. Thurman DJ, Guerrero J. Trends in hospitalization associated with traumatic brain injury. JAMA, 1999; 282(10):954-7.
Unpublished data from Multiple Cause of Death Public Use Data from the National Center for Health Statistics, 1996. Methods are described in Sosin DM, Sniezek JE, Waxweiler RJ. Trends in death associated with traumatic brain injury, 1979-1992. JAMA 1995;273(22):1778-1780.
Analysis by the CDC National Center for Injury Prevention and Control, using data obtained from state health departments in Alaska, Arizona, California (reporting Sacramento County only), Colorado, Louisiana, Maryland, Missouri, New York, Oklahoma, Rhode Island, South Carolina, and Utah. Methods are described in: Centers for Disease Control and Prevention. Traumatic Brain Injury -- Colorado, Missouri, Oklahoma, and Utah, 1990-1993. MMWR 1997;46(1):8-11.
Thurman DJ, Sniezek JE, Johnson D, Greenspan A, Smith SM. Guidelines for Surveillance of Central Nervous System Injury. Atlanta: Centers for Disease Control and Prevention, 1995.
Thurman DJ, Alverson CA, Dunn KA, Guerrero J, Sniezek JE. Traumatic brain injury in the United States: a public health perspective. J Head Trauma Rehab, 1999; 14(6):602-15.
Kraus JF. Epidemiology of head injury. In: Cooper, PR, ed. Head Injury, Third Edition. Baltimore: Williams and Wilkins, 1993; 1-25.
Annegers JF, Grabow HD, Kurland LT, et al. The incidence, cause and secular trends in head injury in Olmstead County, Minnesota, 1935-1974. Neurology 1980;30:912-919.
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Thurman DJ, Jeppson L, Burnett CL, et al. Surveillance of traumatic brain injuries in Utah. West J Med 1996;165:192-196.
Centers for Disease Control and Prevention. Traumatic brain injury -- Colorado, Missouri, Oklahoma, and Utah, 1990-1993. MMWR 1997;46(1):8-11.
Gabella B, Hoffman RE, Marine WW, Stallones L. Urban and rural traumatic brain injuries in Colorado. AEP 1997;7(3):207-212.
Thurman DJ, et al. Traumatic brain injury in the United States: A report to Congress. Atlanta, Centers for Disease Control and Prevention, 1999.
Sosin DM, Sniezek JE, Waxweiler RJ. Trends in death associated with brain injury, 1979-1992. JAMA 1995;273:1778-80.
Max W, MacKenzie EJ, Rice DP. Head injuries: costs and consequences. Journal of Head Trauma Rehabilitation 1991;6(2):76-91.
Thurman DJ, Sniezek JE, Johnson D, Greenspan A, Smith SM. Guidelines for Surveillance of Central Nervous System Injury. Atlanta: Centers for Disease Control and Prevention, 1995.
National Committee for Injury Prevention and Control. Injury Prevention: Meeting the Challenge. New York: Oxford University Press, 1989.
Pope AM, Tarlov AR, editors. Disability in America: Toward a National Agenda for Prevention. Washington, DC: National Academy Press, 1991.
