Ilie G, Boak A, Adlaf EM, Asbridge M, Cusimano MD. Prevalence and correlates of traumatic brain injuries among adolescents. JAMA. doi:10.1001/jama.2013.6750
eTable. Estimates of Traumatic Brain Injury in 7th Through 12th Graders Living in Ontario, Canada
Ilie G, Boak A, Adlaf EM, Asbridge M, Cusimano MD. Prevalence and Correlates of Traumatic Brain Injuries Among Adolescents. JAMA. 2013;309(24):2550-2552. doi:10.1001/jama.2013.6750
Letters Section Editor: Jody W. Zylke, MD, Senior Editor.
Author Affiliations: Injury Prevention Research Office (Dr Ilie; firstname.lastname@example.org) and Division of Neurosurgery (Dr Cusimano), St Michael's Hospital, Toronto, Ontario, Canada; Social and Epidemiological Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada (Ms Boak and Dr Adlaf); and Department of Community Health and Epidemiology, Dalhousie University, Halifax, Nova Scotia, Canada (Dr Asbridge).
To the Editor: Traumatic brain injury (TBI) among adolescents has been identified as an important health priority.1,2 However, studies of TBI among adolescents in large representative samples are lacking.1,2 This information is important to the planning and evaluation of injury prevention efforts, particularly because even minor TBI may have important adverse consequences.2
We describe the prevalence of TBI, mechanisms of injury, and adverse correlates in a large representative sample of adolescents living in Ontario, Canada.
Data were derived from the Centre for Addiction and Mental Health's 2011 Ontario student drug use and health survey, consisting of anonymous, self-administered questionnaires completed in classrooms (62% response rate) by students grades 7-12 (age range: 11-20 years). A complete description of the study, including design and discussion of the validity of self-reports, potential nonresponse bias, and limitations, is available.3
Traumatic brain injury was defined as an acquired head injury in which the student was unconscious for at least 5 minutes or hospitalized overnight.4 Students were asked if they ever had such injury in the past 12 months or in their lifetime (excluding the past 12 months). Students reporting TBI in the past 12 months were asked about the source of the injury. Questions about consumption of alcohol and cannabis use during the last 12 months and usual grades received were also included.
All participants provided signed and parental consent. Research ethics board approval was provided by the Centre for Addiction and Mental Health, York University, and public and Catholic school boards throughout Ontario. The surveys were administered during a class period by field staff. Analyses were based on a complex sample design with 15 strata (region × school level), 181 primary sampling units (schools), and 8915 students.
All analyses used Taylor series linearization available in the complex sample module in SPSS version 20.0 (SPSS Inc). Multinomial logistic regression was performed fitting the 5 factors of sex, grade, past-year alcohol use, past-year cannabis use, and school grades against a 2-tailed P < .05.
The mean (SD) age of participants was 15.1 (1.82) years. The estimated lifetime prevalence of TBI was 20.2% (95% CI, 18.1%-22.4%); 5.6% (95% CI, 4.2%-7.5%) reported at least 1 TBI in the past 12 months (4.3% of girls and 6.9% of boys) and 14.6% (95% CI, 13.4%-15.9%) reported a TBI in their lifetime but not in the past 12 months (12.8% of girls and 16.2% of boys) (eTable).
Sports injuries accounted for more than half of the cases in the past 12 months (56%; 95% CI, 50.5%-63.0%) and were more common among males (46.9% in girls and 63.3% in boys). The multinomial logistic regression model distinguished differences among the 3 TBI groups (lifetime, past 12 months, never) (Wald F34,133 = 17.95, P < .001).
The odds ratio for a lifetime TBI (excluding the past 12 months) was 3.93 (95% CI, 2.13-7.27) for students who reported poor school grades compared with those with high grades (Table). Students who reported occasional to frequent consumption of alcohol and cannabis in the past 12 months had significantly higher odds of TBI in the past 12 months than abstainers.
Twenty percent of Ontario students in grades 7-12 in this provincewide school survey reported a TBI at some point in their life, and 5.6% sustained a TBI in the last 12 months. In the United States, more than half a million adolescents aged 15 years or younger require hospital-based care for head injury annually,2 and our data suggest a much higher number of adolescents may be experiencing these injuries.
The relationship among TBI, substance use, and poorer academic performance needs further investigation. The magnitude of the prevalence estimates and the associated risks identified within this representative sample support suggestions to improve understanding, prevention, and response to TBI among adolescents.1- 3,5,6
Possible bias related to self-report procedures and the preclusion of causal inferences due to the cross-sectional nature of the data are limitations of this study. Even though our data did not present evidence of appreciable bias overall,3 nonresponse bias may exist. Future studies should examine long-term outcomes of injury.
Author Contributions: Dr Ilie had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Ilie, Boak, Asbridge, Cusimano.
Acquisition of data: Boak, Adlaf.
Analysis and interpretation of data: Ilie, Boak, Adlaf, Cusimano.
Drafting of the manuscript: Ilie, Boak.
Critical revision of the manuscript for important intellectual content: Ilie, Boak, Adlaf, Asbridge, Cusimano.
Statistical analysis: Ilie.
Obtained funding: Asbridge, Cusimano.
Administrative, technical, or material support: Boak, Adlaf.
Study supervision: Cusimano.
Conflict of Interest Disclosures: The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none were reported.
Funding/Support: This work was supported by a team grant from the Strategic Teams in Applied Injury Research Program of the Canadian Institutes of Health Research. Additional funding was obtained from a grant from AUTO21, a member of the Networks of Centres of Excellence program that is administered and funded by the Natural Sciences and Engineering Research Council, the Canadian Institutes of Health Research, and the Social Sciences and Humanities Research Council, in partnership with Industry Canada.
Role of the Sponsor: The funding organizations had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
Additional Contributions: We thank Robert E. Mann, PhD, Hayley Hamilton, PhD, and Jürgen Rehm, PhD (all 3 with the Social and Epidemiological Research, Centre for Addiction and Mental Health, Toronto, Ontario, Canada), for their contributions to the manuscript. None received compensation for his or her contribution; however, Drs Mann, Hamilton, and Rehm acknowledge receiving ongoing funding/support from the Ontario Ministry of Health and Long-Term Care.