This study provides information about the external causes, natures and demographic patterns of potential brain injury in a defined Ontario population and about the sequelae of acute injury. The study shows that about 30% of patients with blunt head injury presenting to the emergency department had signs consistent with brain injury. Of these, 56% received a CT scan, and 53% of those scanned had evidence of a brain injury, whereas 10% had evidence of a major intracranial injury. Leading external causes of potential brain injury were falls from heights in young children; motor vehicle injuries, bicycle injuries, sports injuries and fight-related injuries in individuals aged 10–44 years; and falls (all types) in those over the age of 65 years. Males had a rate of head injuries and potential brain injuries that was approximately twice that of females, and both injury rates peaked in boys and young men.
Although head trauma has been recognized as a serious health issue, there are few Canadian epidemiological studies of this issue that include population-based rates, and no studies have comprehensively examined the full spectrum of blunt head traumas seen at emergency departments. Existing studies have been conducted with large, but selected, populations of children18
only, whereas others have examined admissions to hospital20
The increased frequency of head injuries observed in males is consistent with the existing literature, and the peak ratio of 4:1 of head injuries in males compared with females seen among those aged 10–19 years was similar to that reported nationally from US emergency department data.10
The male predominance is probably attributable to differential exposure to risks in certain age groups. Although some studies have identified incidence peaks in teenagers and young adults,13
others have reported higher rates in children aged less than 5 years,1
which are mainly attributable to falls from heights. The peak in injuries from falls among elderly people that has been reported elsewhere,13
and is to some extent reflected in our data, is indicative of the intrinsic risks associated with aging.
We observed that motor vehicle injuries and sports injuries were concentrated in young people, which has been recorded elsewhere.20
Past research has indicated the importance of contact surfaces as a predictor of the severity of injuries,22
and ice and collisions are clearly causal environmental risk factors in ice skating and contact sports like ice hockey.23
Although earlier Canadian research found that almost one-third of cases of head injury admitted to hospital were sustained during fights,20
only 9 cases were identified in our study, almost all of them experienced by young men.
Because of the availability of universal health care coverage in Canada, the observed patterns of injury should not be distorted by differential access to health care, and the present analysis was based in emergency departments that serve the trauma needs of both rural and urban populations. Our study was limited, however, in that there was no standardized protocol for assessing patients. The lack of exact information on the location and context of these injuries also limited our ability to recommend focused alternative preventive measures. Follow-up data on disability and other long-term outcomes were also not available. These can be substantial, because up to 40% of patients with mild traumatic brain injuries remain impaired for at least 1 year,11
and all individuals who survive these injuries need clinical assessment and follow-up.
In conclusion, brain injuries represent a serious and perhaps underappreciated clinical challenge, and these data reinforce the importance of the many external causes that should be targeted for preventive measures.