Injuries Among Infants, Children, Adolescents, and Young Adults Brain
Jess F. Kraus, MPH, PhD; Amy Rock, MPH; Parichehr Hemyari, PhD \s=b\ Blunt
to the brain constitute an enormous public health problem. If a child or young adult
survives a moderate or severe brain injury, there is a strong likelihood of a lifetime of physical and mental impairment as well as tremendous economic and social impact on the family. The magnitude of this problem has only been recently appreciated, yet many questions on the causes and short- or long-term outcomes remain unanswered. One conclusion is clear: prevention is the best solution, but information on the nature of the brain injury, exposure factors, and effectiveness of countermeasures is incomplete. We sought to summarize certain basic epidemiological data on brain injuries in infants, children, adolescents, and young adults as well as findings on incidence of brain injury and current data on demographics and risk factors. We also estimated disability and person-years of life lost from brain injuries and highlight the value of helmets as a countermeasure for several exposures to head injury.
from the epidemiological study of brain injury are hampered by severe limitations in the quality and quantity of information available in the scientific literature. The problems in¬
clude inconsistencies in the scope and definition of brain injury (often called "head injury"), differences in proce¬ dures for case-finding, different data sources, and varying ways in which se¬ verity is measured. These differences result in difficulties when comparing findings across the large number of clinical reports and the few epidemiological studies that have been published. For example, although
Accepted for publication August 23,1989. From the Department of Epidemiology, School
of Public Health, UCLA.
Reprint requests to Department of Epidemiology, School of Public Health, UCLA, Los Angeles, CA 90024-1772 (Dr Kraus).
there are hundreds of published studies on brain injuries of all types and severi¬ ties, to our knowledge there are none that provide specific details on the 0- to 19-year-old age group. In a few reports, data can be found on persons aged 0 to 15 years, but only two such reports have had an epidemiological focus. Thus, new findings are presented from a cohort study of San Diego County, California, residents, aged 0 to 19 years. In addi¬ tion, data from other published sources are used, where available, keeping in mind the limitations described above.
MATERIALS AND METHODS
Findings reported here are limited to two general sources. The first source is informa¬ tion found in the published literature, with emphasis given to data in epidemiological reports. This source was limited to Englishlanguage reports covering the period begin¬ ning 1970. The second source is unpublished findings for the target age group from a 1981 San Diego County brain injury study. In this study, members of the cohort were residents of San Diego County who were hospitalized (or died) in 1981 due to brain injury. Specific details of the study design, study region, case ascertainment, and methods are report¬ ed in detail elsewhere,1'3 and only certain relevant points are summarized here. For purposes of this study, brain injury is physical damage to, or functional impair¬ ment of, the cranial contents from acute me¬ chanical energy exchange exclusive of birth trauma. Cases included in this study were persons with autopsy evidence of brain inju¬ ry who died at the injury scene or were dead on arrival at an emergency department, and those admitted to a hospital with physiciandiagnosed brain injury. Brain injury cases were identified from emergency department and inpatient hospi¬ tal records of acute-care general hospitals in the county; all coroner's records in San Diego County and the adjoining counties of Imperi¬ al, Orange, and Riverside; all death certifi¬ cates (regardless of cause or place of death) for residents of San Diego County; a survey of all nursing homes and extended-care facili¬ ties in San Diego County; and reviews of the
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major hospitals in the three counties bordering San Diego County. Autopsy and nine
coroner's records were obtained for all rele¬ vant fatalities. For people surviving until hospital admis¬ sion, the Glasgow Coma Scale (6CS) was used to assess the level of brain injury sever¬ ity.4 This scale was used consistently in all San Diego County emergency departments during 1981. For a few patients, the verbal response part of the GCS was not recorded (eg, because of intubation), and it was as¬ sumed to be unimpaired if eye and motor response were unimpaired. For a very small number of severely injured patients for whom the GCS was not assessable, the medi¬ cal chart was examined thoroughly and all relevant clinical information was used to judge brain injury severity. The GCS score was measured on arrival at the emergency
department. Patients admitted with a GCS score of 8 or lower were defined as severe cases. Those with a GCS score of 9 or greater were defined as moderate if they had had a hospital stay of at least 48 hours and a GCS score below 13, an abnormal computed tomographic scan, or brain surgery. All other cases were termed mild. These categories and criteria are con¬ sistent with those suggested by Jennett and Teasdale4 and Levin et al.6 Rates of neurologic sequelae, which in¬ cluded such conditions as hemiparesis, dys-
phasia, hearing loss, or cognitive dysfunc¬ tion, were derived for all moderately or severely brain-injured persons admitted to a hospital. These rates were standardized for age, gender, and injury severity at the time of emergency department treatment. Neu¬ rologic limitations included only physiciandiagnosed deficits or limitations at the time of hospital discharge.
Persons under the age of 15 years were excluded from the blood alcohol analysis be¬ cause they generally were not blood-tested by the hospitals or the coroners in 1981. Blood alcohol samples for those aged 15 to 19 years were obtained while in the emergency department, and results were abstracted from the hospital record or the coroner's re¬ port and were not based on police reports. Most hospitals and coroners used a gas Chro¬ matographie method to determine blood al¬ cohol concentration (BAC).
700 r300h 600
Diego, Calif, 1981 Diego, Calif, 1978
Bronx, NY, 1980-1981
North Central Virginia, 1978
o o o o
Fig 2.—Number of and age-specific inci¬ dence rates for brain injuries in 0- to 19-yearolds, San Diego County, California, 1981.
Fig 1 .—Age-specific brain injury incidence rates per 100 000 population, selected US studies.
Mortality About one third of the 75 270 deaths in 1985 among infants and children aged 0 to 19 years in the United States were from injuries of all types.6 The propor¬ tion from brain injury is unknown but can be estimated if the brain injury mor¬ tality rates from Minnesota7 and San Diego County8 for those aged 0 to 14 years are accepted to represent the en¬ tire US population aged 0 to 19 years. Applying the rate from these two loca¬ tions of 10 per 100 000 population per year yields about 7000 brain injury deaths in 1985 or about 29% of all injury deaths in this age group. Incidence Findings on incidence for children or adolescents are limited to only two re¬ ports: the National Head and Spinal Cord Injury Survey9 and new findings for San Diego County residents for 1981. The National Head and Spinal Cord Injury Survey reported a brain injury incidence rate of first hospitaladmitted cases of 230 per 100 000 popu¬ lation under age 15 years during 1974.
Those dead at the scene or dead on ar¬ rival at the hospital were not included in this estimate. The rate for this same age group among residents of San Diego County was 185 per 100 000 during 1981 and includes prehospital and in-hospital deaths.8 The brain injury incidence rate for those aged 15 to 19 years was 294.5 per 100 000. The overall incidence rate for those aged 0 to 19 was 219.4 per 100 000 per year. Gender Data from San Diego County for 1981 show that the incidence of brain injury is 2.1 times higher for males compared with females (293.0 vs 137.9 per 100 000,
Age Data in Fig 1 show age-specific inci¬ dence rates per 100 000 from four re¬ ports that provide such data.1,10"12 Rates for all age groups are presented for con¬ trast. The data show an abrupt rise in rates beginning at about age 15 years. In three of the four reports, peak inci¬ dence occurs at ages 15 to 19 years. Data in Fig 2 give findings for San Diego
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County in 1981. Numbers of cases for each specific age and rates per 100 00Ö by age are presented. The numbers of new cases and rates are generally stable for most ages through age 16 years, but there is an abrupt rise in frequency be¬ ginning at age 17 years. This is seen also in the dramatic increase in the rate for those aged 15 to 19 years. Age and Gender Figure 3 shows age-specific incidence rates for males and females from five population-based studies.1,7,10"12 General¬ ly, the patterns are different, with males having the highest rates for those aged 15 to 24 years. The report from San Diego County for 1978 shows the same pattern for males and females by age. Age-specific rates for males and females are given in Fig 4. Rates for males increase slowly after age 5 years and increase dramatically at ages 15 to 19 years, while the rates for females de¬ cline after age 3 years, rising only mod¬ estly after age 12 years. For all age groups, there are more new brain inju¬ ries for males compared with females.
Race, Ethnicity, and Socioeconomic Status Data for 1981 from San Diego County2 show that brain injury incidence rates were related to the median family in¬ come of the census tract of residency of the brain-injured person. This finding was not altered when age or race/ethni¬
city was considered. Unfortunately, specific exposures by census tracts
measured; hence, the brain risk by factors other attributable injury than socioeconomic status could not be were
500 7001- Males
Diego, Calif, 1981 San Diego, Calif, 1978
Bronx, NY, 1980-1981
North Central Virginia, 1981 Olmsted, Minn, 1965-1974
Fig 4.—Age-specific brain injury rates per 100 000, by gender, San Diego County, Cali¬
fornia, 1981. 200
Severity There are no published reports avail¬ able that deal with severity of brain in¬ juries for children except the San Diego County report of 1981,8 which is limited to those aged 0 to 15 years. Data in Table 1 supplement these findings and
show that over all ages, 5% were dead at the scene or on arrival at the emergency facility, 6% had severe brain injury, 8% had a moderate-level injury, and 82% had mild brain injury (ie, a GCS score of 13 to 15). If those dead at the scene or emergency facility are omitted, then 86% have mild injuries, 8% have moder¬ ate-level injuries, and 6% have severe brain trauma. This pattern varies by age: infants and young adults aged 15 to 19 years have 24% moderate or severe brain injuries or were dead on arrival at the emergency facility from brain
Fig 3. —Age-specific brain injury incidence rates per 100 000 population for males and females,
selected US studies.
Age, Group, y
Age and Severity, San Die Severity, No. (%) of Bi
(11) 10 (5) 14 (6) 16 (7) 49 (9) 95 (8)
3 (6) 54 (100) (7) 1-4 155 8 (4) 12 (7) 185 (100) 5-9 197 13 (6) 5 (2) 229 (100) 10-14 7 (3) 213 5 (2) 241 (100) 15-19 395 38 (7) 43 (8) 525 (99) 68 (5) All Ages 1001 70 (6) 1234 (101) »Dead on arrival (DOA) includes those dead at the scene or pronounced dead at the emergency facility.