Abstract
This study analyzes the increased incidence of concussion among US teens.
In 2016, 19.5% of US adolescents reported at least 1 concussion during their lifetime.1,2 While knowledge about concussion and management of these injuries within the adolescent population have increased over the past decade,3 to our knowledge, no national study has tracked whether rates of concussion have declined or increased. This study estimated trends in the lifetime prevalence of self-reported concussion among a national sample of adolescents between 2016 and 2020.
Methods
This study uses national cross-sectional data from the 2016-2020 Monitoring the Future (MTF) initiative.4 The MTF initiative is an annual school-based survey of 8th-, 10th-, and 12th-graders conducted between February and June each school year; surveys are administered in classrooms and completed during normal class periods. The MTF stopped data collection for the 2020 survey early on March 14, 2020, due to COVID-19 (a representative sample was still maintained). The student response rates between 2016 and 2020 ranged from 79% to 90%. The University of Michigan institutional review board approved this study. A waiver of informed consent was sent to parents providing them a means to decline their child’s participation.
A measure to assess concussion was added to the MTF in 2016, asking respondents the following: “Have you ever had a head injury that was diagnosed as a concussion?” Response options included “no,” “yes, once,” and “yes, more than once.” The measure did not change across the 5 years.
Binary regression models (using Mplus 8.1) estimated linear trends for self-reported concussion; adjusted models controlled for sex, race/ethnicity, grade level, parental education, and participation in sports. Analyses report the unadjusted prevalence ratios, adjusted prevalence ratios, and 95% CIs. Statistical significance was set at α ≤ .05 for a 2-tailed test when assessing linear trends. Full information maximum likelihood estimation was used to account for item missingness for each of the binary regression models. All analyses take into account the complex multistage sampling design, including clustering of respondents in primary sampling units4; weights were incorporated to provide nationally representative estimates along with adjusting for the different sample sizes for 8th-, 10th-, and 12th-graders.
Results
The sample consisted of 52 949 8th-, 10th-, and 12th-graders, of whom 50.3% were girls, and self-reported race/ethnicity was 45.0% White, 11.8% Black, 20.6% Hispanic, and 22.6% other (category included Asian American, American Indian or Alaska Native, and Native Hawaiian or other Pacific Islander) based on predefined categories. Lifetime prevalence of at least 1 self-reported concussion increased from 19.5% (95% CI, 18.5%-20.6%) in 2016 to 24.6% (95% CI, 22.5%-26.7%) in 2020 (adjusted prevalence ratio, 1.05; 95% CI, 1.03-1.08) (Table 1). The increase in lifetime prevalence of only 1 self-reported concussion (adjusted prevalence ratio, 1.05 [95% CI, 1.02-1.08]; 14.0% in 2016 vs 17.7% in 2020) and 2 or more self-reported concussions (adjusted prevalence ratio, 1.05 [95% CI, 1.01-1.11]; 5.5% in 2016 vs 6.8% in 2020) between 2016 and 2020 was statistically significant. Increases in any self-reported concussion were found across both sexes and race/ethnicity categories, among respondents whose parents had a high school diploma or less, and among respondents who participated in competitive sports during the past year (Table 2).
Table 1. Trends in Concussion Among US Adolescents Participating in the MTF, 2016-2020 (N = 52 949)a.
| Self-reported concussionb | No. (%) [95% CI]c | Linear trend, PR (95% CI)e | P value | Linear trend, aPR (95% CI)e | P value | ||||
|---|---|---|---|---|---|---|---|---|---|
| 2016 (n = 13 088) | 2017 (n = 12 320) | 2018 (n = 12 411) | 2019 (n = 11 852) | 2020 (n = 3278)d | |||||
| Any | 2342 (19.5) [18.5-20.6] | 2204 (18.2) [17.2-19.4] | 2365 (19.5) [18.4-20.6] | 2433 (21.6) [20.5-22.8] | 724 (24.6) [22.5-26.7] | 1.07 (1.04-1.10) | <.001 | 1.05 (1.03-1.08) | <.001 |
| 1 | 1709 (14.0) [13.1-14.8] | 1613 (13.3) [12.4-14.3] | 1672 (13.6) [12.7-14.5] | 1686 (14.9) [14.1-15.8] | 515 (17.7) [15.8-19.7] | 1.06 (1.03-1.09) | <.001 | 1.05 (1.02-1.08) | <.001 |
| ≥2 | 633 (5.5) [4.9-6.1] | 591 (4.9) [4.4-5.5] | 693 (5.9) [5.3-6.5] | 747 (6.7) [6.0-7.4] | 209 (6.8) [5.5-8.3] | 1.08 (1.02-1.14) | .005 | 1.05 (1.01-1.11) | .02 |
Abbreviations: aPR, adjusted prevalence ratio; MTF, Monitoring the Future initiative; PR, unadjusted prevalence ratio.
All analyses assessing lifetime self-reported concussion used custom weights to adjust for the different sample sizes for 8th-, 10th-, and 12th-graders. All analyses accounted for the complex sampling design.
Reported across each participant’s lifetime.
On the measure that assessed concussion, 4.9% (2603) of the sample had missing data. Percentages and 95% CIs are based on weighted data; sample sizes are based on unweighted data.
The MTF stopped data collection early on March 14, 2020, due to COVID-19. Values indicate approximately one-third of a typical annual MTF data collection.
Both the unadjusted and adjusted prevalence ratios assessing the linear trend in self-reported concussion are based on a continuous measure of cohort year (2016 = 0, 2017 = 1, 2018 = 2, 2019 = 3, 2020 = 4). Full information maximum likelihood estimation was used to adjust for missing data. Adjusted models included the following covariates: sex, race/ethnicity, grade level of respondent, parental education level, and past-year participation in sports.
Table 2. Trends in Any Self-reported Concussion by Sex, Race, Parental Education, and Past-Year Participation in Competitive Sports (N = 52 949)a.
| Any self-reported concussionb | No. (%) [95% CI]c | Linear trend, aPR (95% CI)e | P value | ||||
|---|---|---|---|---|---|---|---|
| 2016 (n = 13 088) | 2017 (n = 12 320) | 2018 (n = 12 411) | 2019 (n = 11 852) | 2020 (n = 3278)d | |||
| Boys | 1318 (23.2) [21.7-24.6] | 1176 (20.0) [18.6-21.6] | 1255 (21.9) [20.5-23.4] | 1350 (24.5) [23.0-26.1] | 382 (27.3) [24.5-30.3] | 1.05 (1.02-1.08) | <.001 |
| Girls | 920 (15.8) [14.4-17.0] | 910 (16.1) [14.7-17.5] | 961 (17.1) [15.7-18.6] | 997 (18.5) [16.9-20.2] | 332 (21.8) [18.8-25.1] | 1.06 (1.02-1.10) | <.001 |
| White racef | 1346 (23.7) [22.2-25.1] | 1175 (22.5) [21.1-24.1] | 1249 (23.1) [21.5-24.8] | 1397 (25.9) [24.6-27.4] | 428 (27.1) [24.4-29.9] | 1.04 (1.01-1.07) | .005 |
| Other race or ethnicity groupsf | 996 (15.5) [14.4-16.8] | 1029 (14.7) [13.5-15.9] | 1116 (16.5) [15.4-17.7] | 1036 (17.7) [16.3-19.1] | 296 (21.8) [18.5-25.5] | 1.08 (1.04-1.12) | <.001 |
| Less than high school educationg | 765 (16.4) [14.9-18.1] | 786 (16.4) [15.0-18.0] | 806 (17.7) [16.2-19.3] | 791 (19.5) [17.6-21.3] | 262 (25.9) [22.4-29.9] | 1.10 (1.06-1.15) | <.001 |
| Less than BA or BS degreeg | 1362 (22.3) [20.8-23.8] | 1234 (20.6) [19.1-22.1] | 1313 (22.0) [20.5-23.6] | 1422 (23.6) [22.2-25.1] | 412 (24.6) [21.3-28.1] | 1.02 (0.997-1.06) | .08 |
| Nonparticipation in sports | 326 (11.4) [9.8-13.3] | 378 (11.5) [10.1-13.1] | 392 (11.5) [10.0-12.9] | 312 (12.7) [10.8-14.7] | 82 (12.9) [9.5-17.2] | 1.03 (0.968-1.09) | .46 |
| Participation in sports | 1965 (22.4) [21.1-23.6] | 1781 (20.8) [19.5-22.1] | 1925 (22.9) [21.5-24.2] | 1943 (25.1) [23.8-26.5] | 611 (27.4) [24.8-30.0] | 1.06 (1.03-1.08) | <.001 |
Abbreviations: aPR, adjusted prevalence ratio; MTF, Monitoring the Future initiative.
All analyses assessing lifetime self-reported concussion use custom weights to adjust for the different sample sizes for 8th-, 10th-, and 12th-graders. All analyses account for the complex sampling design.
Reported across each participant’s lifetime.
Percentages and 95% CIs are based on weighted data; sample sizes are based on unweighted data.
The MTF stopped data collection early on March 14, 2020, due to COVID-19. Values indicate approximately one-third of a typical annual MTF data collection.
Adjusted prevalence ratio is based on a continuous measure of cohort year (2016 = 0, 2017 = 1, 2018 = 2, 2019 = 3, 2020 = 4). Full information maximum likelihood estimation was used to adjust for missing data. Adjusted models included the following covariates: sex, race/ethnicity, grade level of respondent, parent/guardian level of education, and past-year participation in sports.
Measures for race/ethnicity were self-reported and predefined within the survey. Race was assessed given differences across behavior, social, and academic outcomes.
Indicates parent/guardian education level.
Discussion
Between 2016 and 2020, the estimated percentage of US 8th-, 10th-, and 12th-graders who reported at least 1 diagnosed concussion during their lifetime increased. Although lower prevalence of self-reporting concussions has been found among Hispanic, non-Hispanic other, and non-Hispanic Black adolescents compared with non-Hispanic White adolescents,5 these groups saw increases in self-reported concussion during this time period.
The study also found that trends in self-reporting concussion among adolescents who participate in competitive sports increased during this time period, in contrast with emergency department data that showed a decrease in sports/recreation-related traumatic brain injuries among adolescents and children between 2012 and 2018.6
The increase in reporting of concussion could be due to an increased incidence or greater recognition of symptoms associated with these injuries. Given greater effort to educate the US population regarding the risks associated with head injuries, more adolescents may be seeking care for these injuries, including care from health care professionals outside the emergency department who have appropriate diagnosis and management skills.3
Limitations of the study include the use of self-reported measures of concussion and the use of cross-sectional data. Continued efforts to monitor and prevent concussion are needed.
Section Editor: Jody W. Zylke, MD, Deputy Editor.
References
- 1.Veliz P. Variation in national survey estimates and youth traumatic brain injury-where does the truth lie? JAMA Pediatr. 2019;173(4):399. doi: 10.1001/jamapediatrics.2019.0001 [DOI] [PubMed] [Google Scholar]
- 2.Veliz P, McCabe SE, Eckner JT, Schulenberg JE. Prevalence of concussion among US adolescents and correlated factors. JAMA. 2017;318(12):1180-1182. doi: 10.1001/jama.2017.9087 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Halstead ME, Walter KD, Moffatt K; Council on Sports Medicine and Fitness . Sport-related concussion in children and adolescents. Pediatrics. 2018;142(6):e20183074. doi: 10.1542/peds.2018-3074 [DOI] [PubMed] [Google Scholar]
- 4.Miech RA, Johnston LD, O’Malley PM, Bachman JG, Schulenberg JE, Patrick, ME. Secondary school students. In: Monitoring the Future: National Survey Results on Drug Use, 1975-2018. Vol 1. Institute for Social Research, University of Michigan; 2020. [Google Scholar]
- 5.Haarbauer-Krupa J, Lebrun-Harris LA, Black LI, et al. Comparing prevalence estimates of concussion/head injury in US children and adolescents in national surveys. Ann Epidemiol. 2021;54:11-20. doi: 10.1016/j.annepidem.2020.11.006 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Waltzman D, Womack LS, Thomas KE, Sarmiento K. Trends in emergency department visits for contact sports-related traumatic brain injuries among children—United States, 2001-2018. MMWR Morb Mortal Wkly Rep. 2020;69(27):870-874. doi: 10.15585/mmwr.mm6927a4 [DOI] [PMC free article] [PubMed] [Google Scholar]