Incidence and descriptive epidemiologic features of traumatic brain injury in King County, Washington.

OBJECTIVE: Traumatic brain injury (TBI) is a major cause of disability among US children. Our goal was to obtain population-based data on TBI incidence rates.
METHODS: We conducted surveillance through a stratified random sample of hospital emergency departments in King County, Washington, to identify children 0 to 17 years of age with medically treated TBIs during an 18-month study period in 2007-2008. Additional cases were identified through hospital admission logs and the medical examiner's office. For a sample of nonfatal cases, parents were interviewed to verify TBIs, and medical record data on severity and mechanisms were obtained.
RESULTS: The estimated incidence of TBIs in this setting was 304 cases per 100,000 child-years. The incidence was highest for preschool-aged children and lowest for children aged 5 to 9 years. Rates were uniformly higher for boys than for girls; there was a larger gender gap at older ages. Falls were the main mechanism of injury, especially among preschool-aged children, whereas being struck by or against an object and motor vehicle-related trauma were important contributors for older children. Approximately 97% of TBI cases were mild, although moderate/severe TBI incidence increased with age.
CONCLUSIONS: TBIs led to many emergency department visits involving children, but a large majority of the cases were clinically mild. Incidence rates for King County were well below recent national estimates but within the range reported in previous US studies. Because mechanisms of injury varied greatly according to age, prevention strategies almost certainly must be customized to each age group for greatest impact.