R. Dawn Comstock

Epidemiology of Concussions Among United States High School Athletes in 20 Sports

Background: In the United States (US), an estimated 300,000 sports-related concussions occur annually. Among individuals 15 to 24 years of age, sports are second only to motor vehicle crashes as the leading cause of concussions. Purpose: To investigate the epidemiology of concussions in high school athletes by comparing rates and patterns of concussion among 20 sports. Study Design: Descriptive epidemiology study. Methods: Using an Internet-based data collection tool, RIO, certified athletic trainers from a large, nationally disperse sample of US high schools reported athlete exposure and injury data for 20 sports during the 2008-2010 academic years. Results: During the study period, 1936 concussions were reported during 7,780,064 athlete-exposures (AEs) for an overall injury rate of 2.5 per 10,000 AEs. The injury rate was higher in competition (6.4) than practice (1.1) (rate ratio [RR], 5.7; 95% confidence interval [CI], 5.2-6.3). The majority of concussions resulted from participation in football (47.1%, n = 912), followed by girls’ soccer (8.2%, n = 159), boys’ wrestling (5.8%, n = 112), and girls’ basketball (5.5%, n = 107). Football had the highest concussion rate (6.4), followed by boys’ ice hockey (5.4) and boys’ lacrosse (4.0). Concussions represented a greater proportion of total injuries among boys’ ice hockey (22.2%) than all other sports studied (13.0%) (injury proportion ratio [IPR], 1.7; 95% CI, 1.4-2.1; P < .01). In gender-comparable sports, girls had a higher concussion rate (1.7) than boys (1.0) (RR, 1.7; 95% CI, 1.4-2.0). The most common mechanisms of injury were player-player contact (70.3%) and player–playing surface contact (17.2%). In more than 40% of athletes in sports other than girls’ swimming and girls’ track, concussion symptoms resolved in 3 days or less. Athletes most commonly returned to play in 1 to 3 weeks (55.3%), with 22.8% returning in less than 1 week and 2.0% returning in less than 1 day. Conclusion: Although interest in sports-related concussions is usually focused on full-contact sports like football and ice hockey, concussions occur across a wide variety of high school sports. Concussion rates vary by sport, gender, and type of exposure. An understanding of concussion rates, patterns of injury, and risk factors can drive targeted preventive measures and help reduce the risk for concussion among high school athletes in all sports.

Epidemiology of High School and Collegiate Football Injuries in the United States, 2005–2006

Background Football, one of the most popular sports among male high school students in the United States, is a leading cause of sports-related injuries, with an injury rate almost twice that of basketball, the second most popular sport. Hypothesis Injury patterns will vary between competition and practice exposures and between levels of play (ie, high school vs. National Collegiate Athletic Association [NCAA]). Study Design Descriptive epidemiology study. Methods Football-related injury data were collected over the 2005-2006 school year from 100 nationally representative high schools via High School RIO™ (Reporting Information Online) and from 55 Division I, II, and III colleges via the NCAA Injury Surveillance System. Results Nationally, an estimated 517 726 high school football-related injuries (1881 unweighted injuries) occurred during the 2005-2006 season. The rate of injury per 1000 athlete-exposures was greater during high school competitions (12.04) than during practices (2.56). The rate of injury per 1000 athlete-exposures was also greater during collegiate competitions (40.23) than during practices (5.77). While the overall rate of injury per 1000 athlete-exposures was greater in the NCAA (8.61) than in high school (4.36), high school football players sustained a greater proportion of fractures and concussions. Running plays were the leading cause of injury, with running backs and linebackers being the positions most commonly injured. Conclusion Patterns of football injuries vary, especially by type of exposure and level of play. Future studies should continue to compare differences in injury patterns in high school and collegiate football, with particular emphasis placed on high-risk plays (running plays) and positions (running backs and linebackers).

High School Concussions in the 2008-2009 Academic Year Mechanism, Symptoms, and Management

Background An estimated 136 000 concussions occur per academic year in high schools alone. The effects of repetitive concussions and the potential for catastrophic injury have made concussion an injury of significant concern for young athletes. Purpose The objective of this study was to describe the mechanism of injury, symptoms, and management of sport-related concussions using the High School Reporting Information Online (HS RIO) surveillance system. Study Design Descriptive epidemiology study. Methods All concussions recorded by HS RIO during the 2008-2009 academic year were included. Analyses were performed using SPSS software. Chi-square analysis was performed for all categorical variables. Statistical significance was considered for P < .05. Results A total of 544 concussions were recorded. The most common mechanism (76.2%) was contact with another player, usually a head-to-head collision (52.7%). Headache was experienced in 93.4%; 4.6% lost consciousness. Most (83.4%) had resolution of their symptoms within 1 week. Symptoms lasted longer than 1 month in 1.5%. Computerized neuropsychological testing was used in 25.7% of concussions. When neuropsychological testing was used, athletes were less likely to return to play within 1 week than those for whom it was not used (13.6% vs 32.9%; P < .01). Athletes who had neuropsychological testing appeared less likely to return to play on the same day (0.8% vs 4.2%; P = .056). A greater proportion of injured, nonfootball athletes had computerized neuropsychological testing than injured football players (23% vs 32%; P = .02) Conclusion When computerized neuropsychological testing is used, high school athletes are less likely to be returned to play within 1 week of their injury. Concussed football players are less likely to have computerized neuropsychological testing than those participating in other sports. Loss of consciousness is relatively uncommon among high school athletes who sustain a sport-related concussion. The most common mechanism is contact with another player. Some athletes (1.5%) report symptoms lasting longer than 1 month.

Epidemiology of Severe Injuries Among United States High School Athletes: 2005-2007

Background Over 7 million students participate in high school athletics annually. Despite numerous health benefits, high school athletes are at risk for injury. Hypothesis Severe injury rates and patterns differ by gender and type of exposure. Study Design Descriptive epidemiology study. Methods Sports-related injury data were collected during the 2005-2007 academic years from 100 nationally representative United States high schools via RIO (Reporting Information Online). Severe injury was defined as any injury that resulted in the loss of more than 21 days of sports participation. Results Participating certified athletic trainers (ATCs) reported 1378 severe injuries during 3 550 141 athlete-exposures (0.39 severe injuries per 1000 athletic exposures). Football had the highest severe injury rate (0.69), followed by wrestling (0.52), girls’ basketball (0.34), and girls’ soccer (0.33). The rate in all boys’ sports (0.45) was higher than all girls’ sports (0.26) (rate ratio [RR], 1.74; 95% confidence interval [CI], 1.54-1.98; P < .001). However, among directly comparable sports (soccer, basketball, and baseball/softball), girls sustained a higher severe injury rate (0.29) than boys (0.23) (RR, 1.28; 95% CI, 1.08-1.52; P = .006). More specifically, girls’ basketball had a higher rate (0.34) than boys’ basketball (0.24) (RR, 1.43; 95% CI, 1.10-1.86; P = .009). Differences between boys’ and girls’ soccer and baseball/softball were not statistically significant. The severe injury rate was greater in competition (0.79) than practice (0.24) (RR, 3.30; 95% CI, 2.97-3.67; P < .001). Nationally, high school athletes sustained an estimated 446 715 severe injuries from 2005-2007. The most commonly injured body sites were the knee (29.0%), ankle (12.3%), and shoulder (10.9%). The most common diagnoses were fractures (36.0%), complete ligament sprains (15.3%), and incomplete ligament sprains (14.3%). Of severe sports injuries, 0.3% resulted in medical disqualification for the athletes’ career, and an additional 56.8% resulted in medical disqualification for the entire season. One in 4 (28.3%) severe injuries required surgery, with over half (53.9%) being knee surgeries. Conclusion Severe injury rates and patterns varied by sport, gender, and type of exposure. Because severe injuries negatively affect athletes’ health and often place an increased burden on the health care system, future research should focus on developing interventions to decrease the incidence and severity of sports-related injuries.

The Epidemiology of US High School Basketball Injuries, 2005–2007

Background With more than a million high school athletes playing during the 2006–2007 academic year, basketball is one of the most popular sports in the United States. Hypothesis Basketball injury rates and patterns differ by gender and type of exposure. Study Design Descriptive epidemiology study. Methods Basketball-related injury data were collected during the 2005–2006 and 2006–2007 academic years from 100 nationally representative US high schools via Reporting Information Online. Results High school basketball players sustained 1518 injuries during 780 651 athlete exposures for an injury rate of 1.94 per 1000 athlete exposures. The injury rate per 1000 athlete exposures was greater during competition (3.27) than during practice (1.40; rate ratio, 2.33; 95% confidence interval, 2.10–2.57) and was greater among girls (2.08) than among boys (1.83; rate ratio, 1.14; 95% confidence interval, 1.03–1.26). The ankle/foot (39.7%), knee (14.7%), head/face/neck (13.6%), arm/hand (9.6%), and hip/thigh/upper leg (8.4%) were most commonly injured. The most frequent injury diagnoses were ligament sprains (44.0%), muscle/tendon strains (17.7%), contusions (8.6%), fractures (8.5%), and concussions (7.0%). Female basketball players sustained a greater proportion of concussions (injury proportion ratio, 2.41; 95% confidence interval, 1.49–3.91) and knee injuries (injury proportion ratio, 1.71; 95% confidence interval, 1.27–2.30), whereas boys more frequently sustained fractures (injury proportion ratio, 1.87; 95% confidence interval, 1.27–2.77) and contusions (injury proportion ratio, 1.52; 95% confidence interval, 1.00–2.31). The most common girls’ injury requiring surgery was knee ligament sprains (47.9%). Conclusion High school basketball injury patterns vary by gender and type of exposure. This study suggests several areas of emphasis for targeted injury prevention interventions.

Epidemiology of 1.6 million pediatric soccer-related injuries presenting to US emergency departments from 1990 to 2003

Background As soccer participation in the United States increases, so does the number of children at risk for injury. Purpose To examine pediatric soccer-related injuries presenting to US emergency departments from 1990 to 2003. Study Design Descriptive epidemiology study. Methods A descriptive analysis of nationally representative, pediatric, soccer-related injury data from the US Consumer Product Safety Commissions National Electronic Injury Surveillance System. Results Among those 2 to 18 years of age, a nationally estimated 1 597 528 soccer-related injuries presented to US emergency departments from 1990 to 2003. Mean age was 13.2 years (range, 2-18 years); 58.6% were male. From 1990 to 2003, there was an increase in the absolute number of injuries among girls (P < .0001). The wrist/finger/hand (20.3%), ankle (18.2%), and knee (11.4%) were the most commonly injured body parts. The most common diagnoses were sprain/strain (35.9%), contusion/abrasion (24.1%), and fracture (23.2%). Boys were more likely to have face and head/neck injuries (17.7%; relative risk, 1.40; 95% confidence interval, 1.32-1.49; P < .01) and lacerations/punctures (7.5%; relative risk, 3.31; 95% confidence interval, 2.93-3.74; P < .01) than were girls (12.7% and 2.3%, respectively). Girls were more likely to have ankle injuries (21.8%; relative risk, 1.38; 95% confidence interval, 1.33-1.45; P < .01) and knee injuries (12.9%; relative risk, 1.25; 95% confidence interval, 1.15-1.35; P < .01) than were boys (15.7% and 10.4%, respectively). Girls were more likely to have sprains or strains (42.4%) than were boys (31.3%; relative risk, 1.36; 95% confidence interval, 1.31-1.40; P < .01). Children 2 to 4 years old sustained a higher proportion of face and head/neck injuries (41.0%) than did older children (15.5%; relative risk, 2.65; 95% confidence interval, 2.09-3.36; P < .01). Conclusion When comparing these data to available national statistics that estimate participation in youth soccer, true injury rates may actually be decreasing for boys and girls. Young children should be closely supervised because of risk of head injuries and rate of hospitalization. The establishment of a national database of soccer participation and injury data is needed to better identify injury risks.

The Epidemiology of United States High School Soccer Injuries, 2005–2007

Background United States high school soccer participation increased 5 fold over the last 30 years. With increased participation comes increased injury incidence. Hypothesis High school soccer injury patterns will vary by gender and type of exposure. Study Design Descriptive epidemiologic study. Methods Soccer-related injury data were collected over the 2005–2006 and 2006–2007 school years from 100 nationally representative United States high schools via Reporting Information Online (RIO, an Internet-based sports-related injury surveillance system). Results Participating certified athletic trainers reported 1524 soccer injuries during 637 446 athlete exposures (AEs), for an injury rate of 2.39 per 1000 AEs, corresponding to a nationally estimated 807 492 soccer-related injuries during the 2005–2006 and 2006–2007 seasons. The injury rate per 1000 AEs was greater during competition (4.77) than practice (1.37) (rate ratio [RR] = 3.49; 95% confidence interval [CI], 3.15–3.87). Overall, the most frequent diagnoses were incomplete ligament sprains (26.8%), incomplete muscle strains (17.9%), contusions (13.8%), and concussions (10.8%). The most commonly injured body sites were the ankle (23.4%), knee (18.7%), head/face (13.7%), and thigh/upper leg (13.1%). Similar proportions of boys (57.9%) and girls (53.9%) returned to activity in <1 week. During competition, girls sustained complete knee ligament sprains requiring surgery at a rate of 26.4 per 100 000 AEs, higher than the rate among boys during competition (1.98 per 100 000 AEs) (RR = 13.3; 95% CI, 3.15–56.35) and among girls during practice (2.34 per 100 000 AEs) (RR = 11.3; 95% CI, 4.31–29.58). Player-to-player contact was more common among competition injuries (injury proportion ratio [IPR] = 2.42; 95% CI, 2.01–2.92), while noncontact mechanisms were more common among practice injuries (IPR = 2.39; 95% CI, 1.90–3.01). Conclusions High school soccer injury patterns vary by gender and type of exposure. Identifying such differences in injury patterns is the important first step in the development of evidence-based, targeted injury prevention efforts.

National High School Athlete Concussion Rates From 2005-2006 to 2011-2012

Background: High school athletes are at risk for concussions. Although a previously published study showed an increase in concussion rates for a single school district, it remains unknown if the rate of concussions among high school athletes is increasing nationally. Purpose: To investigate national high school athlete concussion rates over time. Study Design: Descriptive epidemiologic study. Methods: The rate of concussions per 1000 athlete-exposures was calculated for academic years 2005-2006 through 2011-2012 using the High School Reporting Information Online sports injury surveillance system. Results: During the 7-year period of this study, High School Reporting Information Online captured 4024 concussions with overall concussion diagnosis rates increasing significantly from 0.23 to 0.51 (P = .004). Concussion diagnosis rates increased for each of the 9 sports studied, with 5 sports having statistically significant increases over this 7-year period. Conclusion: The study analysis indicates that national concussion diagnosis rates for high school sports have increased significantly over time.

Epidemiology of Knee Injuries Among Boys and Girls in US High School Athletics

Background The knee joint is the second most commonly injured body site and the leading cause of high school sports-related surgeries. Knee injuries are among the most economically costly sports injuries and may require subsequent surgery or extensive and expensive rehabilitation. Purpose To report the incidence, risk, and severity of high school knee injuries across sports, genders, and type of exposure. Study Design Descriptive epidemiology study. Methods During the 2005–2006 and 2006–2007 school years, 100 US high schools were randomly selected for a nationally representative sample. Certified athletic trainers tracked injuries using an online injury surveillance system, High School RIO™, in 9 high school sports. Results There were 1383 knee injuries reported during 3 551 131 athlete exposures for a rate of 3.89 knee injuries per 10 000 athlete exposures. Although boys had a higher overall rate of knee injury (rate ratio, 1.38; confidence interval, 1.22–1.55), girls were twice as likely to sustain knee injuries requiring surgery (major knee injuries) than were boys (injury proportion ratio, 1.98; confidence interval, 1.45–2.70) and twice as likely to incur noncontact major knee injuries (injury proportion ratio, 1.98; confidence interval, 1.23–3.19) as were boys. Although illegal play was identified as a contributing factor in only 5.7% of all knee injuries, 20% of knee injuries resulting from illegal play required surgery. Conclusion Knee injury rates and patterns varied by sport, gender, and type of exposure. Identified gender differences included differences in injury rates, injury severity, and basic injury mechanism. Further surveillance is crucial for the development of targeted, evidence-based injury prevention strategies to reduce the morbidity and economic impact of knee surgeries.

Patterns of Recurrent Injuries Among US High School Athletes, 2005-2008

Background High school sports participants sustain millions of injuries annually; many are recurrent injuries that can be more severe than new injuries. Hypothesis Recurrent injury patterns differ from new injury patterns by sport and gender. Study Design Descriptive epidemiology study. Methods High school sports injury data for the 2005 through 2008 academic years were collected via High School Reporting Information Online (RIO) from a nationally representative sample of 100 US high schools. Results From 2005 through 2008, certified athletic trainers reported 13 755 injuries during 5 627 921 athlete exposures (24.4 injuries per 10 000 athlete exposures). Recurrent injuries accounted for 10.5% of all injuries. Football players had the highest rate of recurrent injury (4.36 per 10 000 athlete exposures). Girls had higher rates of recurrent injuries than boys in soccer (injury rate ratio = 1.39; 95% confidence interval, 1.07-1.82). Recurrent injuries most often involved the ankle (28.3%), knee (16.8%), head/ face (12.1%), and shoulder (12.0%), and were most often ligament sprains (incomplete tears) (34.9%), muscle strains (incomplete tears) (13.3%), and concussions (11.6%). A greater proportion of recurrent injuries than new injuries resulted in the student choosing to end participation (recurrent = 2.4%, new = 0.7%). Recurrent shoulder injuries were more likely to require surgery than new shoulder injuries (injury proportion ratio = 4.51; 95% confidence interval, 2.82-7.20). Conclusion Recurrent injury rates and patterns differed by sport. Because recurrent injuries can have severe consequences on an athletes health and future sports participation, injury prevention must be a priority. Knowledge of injury patterns can drive targeted preventive efforts.