Concussion rate doubled in decade
- There are between an estimated 1.6 and 3.8 million sports-related concussions in the United States every year. (1,2)
- Reducing the incidence of concussion in sports has become a public health priority. (15)
- High school athletes sustain an estimated 300,000 concussions per year. (10)
- A 2011 study (8) of U.S. high schools with at least one certified athletic trainer (AT) on staff found that concussions accounted for nearly 15% of all sports-related injuries reported to ATs and which resulted in a loss of at least one day of play.
- Another 2011 study (4) reported that, for all athletes, concussion rates in high school athletics have increased by 16% annually from the 1997-1998 to 2007-2008 academic years, possibly resulting from an increase in injury or diagnosis.
- A 2012 paper presented to the American Academy of Pediatrics' annual meeting (19) suggests that high schools with ATs have concussion rates much higher than those that don't (8 times higher in girl's soccer and 4.5 times higher in girls' basketball). Again, the reason for such higher concussion rates may be due to the fact that athletic trainers are better able to spot the often subtle signs of concussions.
- A 2012 study (10) of 20 high school sports reported that concussions accounted for 13.2% of all injuries in the sports studied, two thirds (66.6%) of which occurred during competition and one-third (33.4%) during practice.
- According to the Centers for Disease Control and Prevention (CDC) (12), an estimated 2.7 million children aged ≤19 years were treated annually in emergency departments (EDs) for sports and recreation-related injuries during 2001-2009. Approximately 6.5%, or 173,285, of these injuries, were traumatic brain injuries (TBIs), including concussion.
- During the same period, the estimated number of sports and recreation-related TBI visits to EDs increased 62%, from 153,375 to 248,418, with the highest rates among males aged 10-19 years. The rate of TBI visits also increased 57% from 153,375 to 248,418 during 2001-2009. The authors of the CDC report speculated that the increases were likely due to increased awareness of the importance of early diagnosis of TBI.
- For young people ages 15 to 24 years, sports are the second leading cause of traumatic brain injury behind only motor vehicle crashes. (3,13) [Editor's note: the study on which this statistic is based is 17 years old and based on data from 1991, so it may be outdated].
Concussion rates are increasing in high school sports.
The current rates per 100,000 athletic exposures (an AE is one athlete participating in one organized high school athletic practice or competition, regardless of the amount of time played), according to the two most recent studies (8,10) are as follows:
- Football: 64 -76.8
- Boys' ice hockey: 54
- Girl's soccer: 33
- Boys' lacrosse: 40 - 46.6
- Girls' lacrosse: 31 - 35
- Boys' soccer: 19 - 19.2
- Boys' wrestling: 22 - 23.9
- Girls' basketball: 18.6 - 21
- Girls' softball: 16 - 16.3
- Boys' basketball: 16 - 21.2
- Girls' field hockey: 22 - 24.9
- Cheerleading: 11.5 to 14
- Girls' volleyball: 6 - 8.6
- Boys' baseball: Between 4.6 - 5
- Girls' gymnastics: 7
- Girls' swim/dive: 2
- Girls' track/field: 2
- Boys' track/field: 2
- Boys' swim/dive: 1
Football players most at risk
- High school football is consistently shown in studies to be the sport with the greatest proportion of concussions (47.1%) and the highest concussion rate (6.4 concussions per 10,000 athletic exposures).
- At least one player sustains a mild concussion in nearly every American football game.
- There are approximately 67,000 diagnosed concussions in high school football every year. (9)
- According to research by The New York Times, at least 50 youth football players (high school or younger) from 20 different states have died or sustained serious head injuries on the field since 1997.
- Anecdotal evidence from athletic trainers suggests that only about 5% of high school players suffer a concussion each season (21) but formal studies surveying players suggest the number is much higher, with close to 50% saying they have experienced concussion symptoms (22) and fully one-third reporting two or more concussions in a single season.
- According to the National Center for Catastrophic Sport Injury Research (23), there were no direct fatalities in high school, college or youth football in 2012. IIt was the first year with no fatalities in high school football since 1990.
- Between 1931 and 2011, 678 high school football players died, two-thirds from helmet-to-helmet contact (23).
- According to a study reported in the July 2007 issue of The American Journal of Sports Medicine:
- Football players suffer the most brain injuries of any sport;
- An unacceptably high percentage (39%) of high school and collegiate football players suffering catastrophic head injuries (death, nonfatal but causing permanent neurologic functional disability, and serious injury but leaving no permanent functional disability) during the period 1989 to 2002 were still playing with neurologic symptoms at the time of the catastrophic event.
Girls more prone to concussion?
- Some studies suggest that girls have higher concussion rates than boys and that concussions represent a greater proportion of all injuries in girls than in boys, but the trend in peer-reviewed studies appears to be towards finding no significant gender differences.
- A study published in the Winter 2007-2008 Journal of Athletic Training (3) suggested that girls were much more susceptible to concussions in sports like soccer and basketball than boys,
- Two more recent studies suggested that, while the concussion rate for girls in soccer was higher (33.0 per 100,000 AEs versus 19.2 per 100,000 AES in the 2009-2010 school year)(8), the concussion rate for basketball was actually higher for boys (21.2) than girls (18.6).
- A more recent study of high school sports (10) found that the concussion rate for girls' basketball (21) was higher than that in boys' basketball (16) and soccer (34 versus 19).
- Whether female high school athletes are more likely than male athletes for have symptoms that persist longer than 7 days is also unclear. While a 2011 study (8) found such a gender gap, a 2010 study (5), reported no gender difference in the time symptoms took to clear or in the time athletes took to return to play. A study conducted by researchers at Vanderbilt published in late 2012 (14) found that girls did not appear to be worse off after sports-related concussion than boys, either in terms of concussion symptoms or on neurocognitive tests measuring reaction time and visual memory. The only significant gender-related difference the study identified was that female high school soccer players reported a greater number of post-concussion symptoms, although their total symptom score, when the symptoms were ranked on a 6-point scale for severity, were not statistically different from those of the male athletes.
The reason for the higher concussion rate for girls, if one exists at all, are unknown, although some have theorized that female athletes have weaker neck muscles and a small head mass than male athletes (5,10,17,18) or that male athletes are more reluctant to report concussions for fear of being removed from competition, which may result in the well-documented underestimation of the incidence of concussion among boys (6,15-18) and that female athletes may be generally more honest about reporting injuries than male athletes, a reporting bias resulting in a greater proportion of boys' concussions going undiagnosed than girls', thereby misrepresenting girls as having higher concussion rates. (10,17,18) A third explanation for gender differences in concussion may be possible hormonal factors, such as the protective effect of estrogen in males. (17,18)
- The percentage of high school athletes sustaining a concussion who had previously sustained a sports-related concussion either that season or in a previous season is holding steady at about 11%:
- in two studies released in 2011, the first (4) covering the 11-year period from 1997 to 2008 at high schools in one large suburban school district, each with an athletic trainer, and the second (8) covering the 2009-2010 school year for a representative sample of U.S. high schools with athletic trainers, both found that 11% of concussions in the high school sports studied were repeat concussions;
- the most recent study of concussions in high school sports (10) reported that 11.5% of concussions were of the recurrent variety.
- almost 20% of concussions in boys' wrestling were recurrent concussions. (10)
- Once an athlete has suffered an initial concussion, his or her chances of a second one are 3 to 6 times greater than an athlete who has never sustained a concussion.
- Slightly more than a third of high school players in one recent survey who reported two or more concussions within the same school year. (8)
- High school athletes who suffer 3 or more concussions are at increased risk of experiencing loss of consciousness (8-fold greater risk), anterograde/post-traumatic amnesia/PTA (reduced ability to form new memories after a brain injury) (5.5-fold greater risk), and confusion (5.1-fold greater risk) after a subsequent concussion.
- Children who are seen in a hospital emergency room for a head injury, concussion, skull fracture or intracranial injury) are more than twice as likely to sustain a subsequent head injury of similar type within 12 months as are children seeking care for an injury not related to the head, regardless of their age.
Recovery time varies
- A 2007 study found that:
- post-concussion symptoms resolved in 3 days or less in more than 50% of the high school athletes in sports other than girls' basketball and softball;
- The same study found that more than 50% of athletes returned to play in 9 days or less;
- From 30 to 80 percent of those athletes who have sustained concussions still had post-concussion signs and symptoms (e.g. are symptomatic) three months after being injured; about one in seven were still symptomatic after one year.
- A 2010 study of high school athletes in a large, suburban public school system,7 found, however, that, for most, concussion symptoms clear within a week.
- 27.0% had symptoms resolve in less than 24 hours;
- 36.2% between 1 and 3 days;
- 20.2% between 4 and 6 days;
- 15.1% had symptoms lasting more than a week but less than a month; and
- 1.5% were still experiencing symptoms more than a month after injury.
- Those results were confirmed in a 2011 study8 of U.S. high schools with athletic trainers for the 2009-2010 school year:
- 23.5% had symptoms resolve or clear in less than 24 hours;
- 33.8% between 1 and 3 days;
- 20.6% between 4 and 6 days;
- 19.6 between 1 week and 1 month; and
- 2.8% more than a month.
- The most recent study of U.S. high school athletes covering the 2008-2010 period showed that in more than 40% of athletes in 18 of the 20 sports studied (all but girls' swimming and girls' track) concussion symptoms resolved in 3 days or less, but that, although approximately one-fourth of all athletes studied had concussion symptoms resolve within a day, 2% returned to play the same day, a practice in clear violation of the current consensus statement on sports-related concussion (11), which recommends that no adolescent athlete who sustains a concussion should return to play on the day of injury.
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6. Id. at 599 nn. 24, 33.
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Most recently revised and updated May 17, 2013