Prevalence of Concussion Among US Adolescents and Correlated Factors

Little is known about the prevalence and correlates of concussions among US adolescents. A regional study of Canadian adolescents found that approximately 20% had sustained a concussion.^1,2 Providing a national baseline of concussion prevalence and correlates is necessary to target and monitor prevention efforts to reduce these types of injuries during this important developmental period.

This study used cross-sectional data from the 2016 Monitoring the Future (MTF) survey, an annual, in-school survey of US students in grades 8, 10, and 12.³ Response rates for the 2016 MTF survey were 90% for grade 8, 89% for grade 10, and 81% for grade 12. The institutional review board at the University of Michigan approved this study. A waiver of informed consent was sent to parents providing them a means to decline their child’s participation if necessary.

An item to assess concussion was developed in collaboration with concussion experts, pilot tested, and added to the MTF survey in 2016. Respondents were asked: “Have you ever had a head injury that was diagnosed as a concussion?” Response options included “no,” “yes, once,” and “yes, more than once.”

Sociodemographic variables included sex, race/ethnicity, grade level, and participation in competitive sport within the past 12 months. Participation in competitive sport assessed 21 different types of sports and was recoded into a mutually exclusive variable that included 5 participation categories: no sports, contact sports, semicontact sports, noncontact sports, and other sports (see Table 1 for details).

Binary logistic regression models (using STATA [StataCorp], version 14.0) were used to estimate odds ratios (ORs), adjusted odds ratios (AORs) and 95% CIs. All binary logistic regression models estimating the AORs simultaneously controlled for sociodemographic variables (listed in Table 2). Analyses used weights to account for the probability of selection into the sample and adjust for the different sample sizes for grades 8, 10, and 12. Two-tailed significance tests with an α of .05 were used to assess statistical significance. Given that 10.4% of the sample had missing data on at least 1 of the variables used in the analyses, multiple regression imputation was used to impute missing data (see Table 1 for details).

Among the 13 088 adolescents who participated in the 2016 MTF survey, 50.2% were female, 46.8% were white, and the modal age was 16 years (range, 12-18). An estimated 19.5% of adolescents (95% CI, 18.5%-20.6%) reported at least 1 diagnosed concussion in their lifetime (Table 1); 14.0% (95% CI, 13.1%-14.8%) reported 1 diagnosed concussion; and 5.5% (95% CI, 4.9%-6.1%) reported being diagnosed with more than 1 concussion.

Several factors were associated with higher lifetime prevalence of reporting a diagnosed concussion (Table 2): being male, white, in a higher grade, and participating in competitive sports. In particular, participation in contact sports was associated with a higher adjusted odds of lifetime prevalence of being diagnosed with more than 1 concussion (11.1%; AOR, 4.83 [95% CI, 3.29-4.83]).

In 2016, 19.5% of US adolescents in grades 8, 10, and 12 reported at least 1 diagnosed concussion during their lifetime, and 5.5% reported being diagnosed with more than 1 concussion. Involvement in competitive sports was associated with a greater odds of lifetime diagnosis of concussions. These findings are consistent with those from emergency department and regional studies that show that participation in sports is one of the leading causes of concussions among adolescents,^1,4 and that youth involved in contact sports are at an increased risk for sustaining concussions.⁵

The prevalence of concussions among adolescents reported here is much higher than reported from emergency departments (ie, between 4% and 5%),⁶ but consistent with regional surveys (ie, 20%).^1,2 Greater effort to track concussions using large-scale epidemiological data are needed to identify high-risk subpopulations and monitor prevention efforts.

Study limitations include the self-report measure of concussion; responses may be biased due to respondents misunderstanding the question or providing inaccurate information. The cross-sectional design precluded causal or temporal interpretation of the associations found. Temporal ordering of sport participation and diagnosed concussion could not be determined due to the wording of the questions in the survey.

Accepted for Publication: June 21, 2017.

Corresponding Author: Phil Veliz, PhD, Institute for Research on Women and Gender, University of Michigan, 204 S State St, Ann Arbor, MI 48109 (ptveliz@umich.edu).

Author Contributions: Drs Veliz and Schulenberg had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Veliz, McCabe, Schulenberg.

Drafting of the manuscript: Veliz, Schulenberg.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Veliz.

Obtained funding: McCabe, Schulenberg.

Administrative, technical, or material support: Eckner, Schulenberg.

Supervision: McCabe, Schulenberg.

Conflict of Interest Disclosures: All 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 research grants L40DA042452 (Dr Veliz), R01DA031160, and R01DA036541 (both Dr McCabe) from the National Institute on Drug Abuse (NIDA), K23HD078502 from the National Institute of Child Health and Human Development (Dr Eckner), and R01CA203809 from the National Cancer Institute (NCI; Dr McCabe) of the National Institutes of Health (NIH). The Monitoring the Future data were collected under grant R01DA001411 from NIDA (Dr Schulenberg).

Role of the Funder/Sponsor: The NIH had no involvement in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.

Disclaimer: The content is solely the responsibility of the authors and does not necessarily represent the official views of NIDA, NCI, or the NIH.