Concussions From Sports Among High School Students, 2017

A concussion is a type of traumatic brain injury. High school athletes are more susceptible to concussions than older athletes and take longer to recover, and the effects — short- and long-term — can include changes in thinking, mood and behavior. Yet the usual ways of counting youth concussions miss many of them:

• emergency department data miss concussions treated elsewhere;
• athletic trainers' reports miss concussions outside school sports;
• both miss concussions that are never treated.

In 2017, CDC added a concussion question to the national Youth Risk Behavior Survey (YRBS) for the first time. After a definition — "when a blow or a jolt to the head causes problems such as headaches, dizziness, being dazed or confused, difficulty remembering or concentrating, vomiting, blurred vision, or being knocked out" — students were asked how many times in the past 12 months they had a concussion from playing a sport or being physically active. 14,765 students in grades 9–12 answered the anonymous survey.

Visual abstract. Credit: Centers for Disease Control and Prevention.

How common

• 15.1% of high school students — about 2.5 million — reported at least one concussion in the past year.
• 6.0% — about 1.0 million — reported two or more.
• By number: 9.1% had one, 3.0% two, 1.0% three, and 2.0% four or more.

Concussions were significantly more common among male students than female students, and among students who played on a sports team than among those who didn't. Black and Hispanic students were more likely than white students to report four or more concussions (3.7% and 2.4%, compared with 1.3%).

More teams, more concussions

Compared with students on one team, the odds of a concussion were 1.5 times as high for students on two teams, and 2.2 times as high for those on three or more. The rise held in every sex, grade and racial/ethnic group studied.

Why the numbers are higher than other estimates

The 15.1% is similar to a 2013 study of YRBS data from three states, which found 17.6% to 20.1%. It is higher than estimates from emergency departments (for example, 622.5 visits per 100,000 people aged 10–14) or athletic trainers (1.8 per 100 high school and college athletes per season).

Underreporting is a known problem: in one study of high school athletes with concussions, 40% said their coach didn't know about their symptoms. An anonymous survey, with no risk of losing playing time, may capture concussions that other sources miss.

Limitations

• Concussions were self-reported and not checked against medical records. Students might also have counted a concussion from before the 12-month window, or mistaken symptoms like a headache for one.
• Only students attending school were surveyed; in 2013, about 5% of 16- and 17-year-olds were not enrolled and had no high school credential.
• The survey can't show how many repeat concussions followed one that hadn't healed — though playing with a symptomatic concussion raises the risk of another, more serious one.
• It can't separate team sports from other physical activity.

What to do

A 2014 National Academy of Sciences report called for more complete estimates of youth sports concussions, and CDC is working toward a National Concussion Surveillance System covering all traumatic brain injuries across the lifespan. Meanwhile, the authors recommend:

• Safety culture: make concussion prevention and management an explicit part of sports, and have coaches and parents stress rules of play that protect players.
• Targeted education: reach students who play on several teams, and Black and Hispanic students about the risks of multiple concussions.
• Remove and clear: any athlete with a suspected concussion should leave practice or competition and not return without a health care provider's clearance. Playing on can worsen symptoms and raise the risk of a second concussion, so athletes need to know why reporting symptoms matters.
• Helmets: in recreation, bicycle helmets have been shown to reduce head injuries.
• Return safely: students, parents, coaches, teachers and providers should all know how to bring a student safely back to school and play.

Sources

Based on DePadilla L, Miller GF, Jones SE, Peterson AB, Breiding MJ, "Self-Reported Concussions from Playing a Sport or Being Physically Active Among High School Students — United States, 2017," Morbidity and Mortality Weekly Report 67(24), Centers for Disease Control and Prevention; a work of the United States government in the public domain. Original report.