Sex Differences in the Clinical Incidence of Concussions, Missed School Days, and Time Loss in High School Student-Athletes: Part 1

Injury Characteristics and Risk Factors of Sport-Related Concussion Among High School Athletes in School-Sponsored Sports

BACKGROUND AND OBJECTIVES

Over a million sport-related concussions (SRC) affect children annually in the United States, posing a significant public health concern. Limited data exist on the premorbid risk factors and injury characteristics of SRCs in high school athletes. This study aims to understand acute SRC injury characteristics and describe premorbid risk factors in high school athletes.

METHODS

Athletes (aged 14-19 years) from 19 central Illinois high schools participating in school-sponsored sports from 2009 to 2023 were included. Sports Concussion Assessment Tool evaluations were performed as part of preseason and postinjury evaluations. Injury characteristics, such as mechanism, setting, and symptoms, were described using all SRCs in the study period. Odds ratios (OR) were computed to determine risk factors using athletes with a baseline Sports Concussion Assessment Tool before SRC and nonconcussed athletes.

RESULTS

In total, 4360 athletes were included (3953 without SRC; 407 with ≥1 SRC of whom 168 had a previous baseline). Overall, 24.2% of SRCs occurred in female athletes, and most SRCs occurred in competitions while playing American football (52.3%), soccer (20.4%), and basketball (7.6%). Blow/hit to the head was the most common mechanism. Headache was the most severe symptom (2.55 ± 1.51 [SD]), and symptoms of emotionality and nervousness/anxiety were significantly more severe in female athletes (P < .05). Students with previous concussions (OR 2.64 95% CI [1.81, 3.78]), previous hospitalization for head injury (OR 3.19 95% CI [1.9, 5.14]), headache/migraine disorders (OR 2.23 95% CI [1.29, 3.66]), and learning disabilities (OR 2.69 95% CI [1.47, 4.61]) had greater odds of SRC (P < .05). Lower odds of SRC were seen in athletes identifying as Black or African American (vs White) (OR 0.54 95% CI [0.32, 0.86]) and those attending larger (vs smaller) schools (OR 0.64 95% CI [0.46, 0.88]).

CONCLUSION

Understanding SRC risk factors and characteristics in high school athletes is critical for developing prevention and management programs, guiding neurosurgeons in mitigating SRC risk, and informing return-to-play decisions.

Association of concussion history with psychiatric symptoms, limbic system structure, and kynurenine pathway metabolites in healthy, collegiate-aged athletes

Psychiatric outcomes are commonly observed in individuals with repeated concussions, though their underlying mechanism is unknown. One potential mechanism linking concussion with psychiatric symptoms is inflammation-induced activation of the kynurenine pathway, which is thought to play a role in the pathogenesis of mood disorders. Here, we investigated the association of prior concussion with multiple psychiatric-related outcomes in otherwise healthy male and female collegiate-aged athletes (N = 212) with varying histories of concussion recruited from the community. Specially, we tested the hypotheses that concussion history is associated with worse psychiatric symptoms, limbic system structural abnormalities (hippocampal volume, white matter microstructure assessed using neurite orientation dispersion and density imaging; NODDI), and elevations in kynurenine pathway (KP) metabolites (e.g., Quinolinic acid; QuinA). Given known sex-effects on concussion risk and recovery, psychiatric outcomes, and the kynurenine pathway, the moderating effect of sex was considered for all analyses. More concussions were associated with greater depression, anxiety, and anhedonia symptoms in female athletes (ps ≤ 0.005) and greater depression symptoms in male athletes (p = 0.011). More concussions were associated with smaller bilateral hippocampal tail (ps < 0.010) and left hippocampal body (p < 0.001) volumes across male and female athletes. Prior concussion was also associated with elevations in the orientation dispersion index (ODI) and lower intracellular volume fraction in several white matter tracts including the in uncinate fasciculus, cingulum-gyrus, and forceps major and minor, with evidence of female-specific associations in select regions. Regarding serum KP metabolites, more concussions were associated with elevated QuinA in females and lower tryptophan in males (ps ≤ 0.010). Finally, serum levels of QuinA were associated with elevated ODI (male and female athletes) and worse anxiety symptoms (females only), while higher ODI in female athletes and smaller hippocampal volumes in male athletes were associated with more severe anxiety and depression symptoms (ps ≤ 0.05). These data suggest that cumulative concussion is associated with psychiatric symptoms and limbic system structure in healthy athletes, with increased susceptibility to these effects in female athletes. Moreover, the associations of outcomes with serum KP metabolites highlight the KP as one potential molecular pathway underlying these observations.

Most cited articles involving lacrosse since 1990 primarily focus on concussion and traumatic brain injury

OBJECTIVES

The purpose of this study was to identify the 50 most-cited publications relating to lacrosse since 1990 and conduct a bibliometric analysis of the identified studies.

METHODS

Clarivate Analytics Web of Science database was queried to identify all publication titles, abstracts, and keywords for the term 'lacrosse' on 9 June 2023. The resulting articles were sorted by total number of citations. Titles and abstracts were included based on their relevance to lacrosse. Once the 50 most cited articles were identified, each article was further analyzed to obtain author name, publication year, country of origin, journal name, article type, research topic, competition level, total number of citations, and the level of evidence. Citation density (total number of citations/years since publication) was calculated and recorded for each of the most-cited studies.

RESULTS

The 50 most-cited articles were cited 4237 of times with an average of 84 citations per article. The most cited article was cited 637 (15.0%) times. The articles came from 2 different countries, with the United States and Australia comprising 49 and 1 articles, respectively. All articles were published in English. The American Journal of Sports Medicine published the most articles (n = 21, 42.0%). The most studied topic was concussion/traumatic brain injury (n = 18) followed by studies assessing all injuries (n = 7). Collegiate-level lacrosse was the most studied level of competition (n = 22), while high school-level followed (n = 12).

CONCLUSIONS

The majority of the 50 most-cited articles related to lacrosse since 1990 focus on the prevalence, diagnosis and identification of concussion/traumatic brain injury in high school and collegiate-level athletes. These articles are predominantly epidemiological or cohort studies with Level III or IV evidence that almost unanimously originate from the United States.

Missing School Days Following Sport-Related Concussion in High School Athletes

Importance

Sport-related concussions (SRC) can significantly impact students' attendance and academic performance, highlighting the importance of gradual return-to-learn protocols for recovery. Understanding the association between missed school days and recovery, especially across genders, is vital for effective concussion management in high school athletes.

Objectives

To describe missed school days in high school athletes with SRC and to determine associations between missed school days and authorized clearance to return to competition; secondarily, to determine whether school days missed differed by gender.

Design, Setting, and Participants

Cohort study among student athletes participating in athletics sponsored by the Michigan High School Athletic Association (MHSAA) during academic years 2015 to 2023. SRC was a participant eligibility criterion and was defined as a head injury during participation in a MHSAA-sanctioned event. Data were analyzed from August 2015 to June 2023.

Exposures

Primary exposure was missed school days; additional exposures included gender, year of season, concussion history, event type, sport level, contact level, and athletic trainer involvement.

Main Outcome and Measure

The primary outcome was time to full unrestricted clearance following SRC.

Results

The analysis included a total of 20 934 individuals with SRC (13 869 boys [66.25%]). Gender (χ23 = 167.40; P < .001), season (χ221 = 57.41; P < .001), event type (χ23 = 99.29; P < .001), sport level (χ29 = 68.15; P < .001), contact level (χ26 = 56.73; P < .001), and initial evaluation (χ23 = 147.13; P < .001) were independently associated with missed school days. Athletes took a median (IQR) of 11 (7-16) days to return to full unrestricted clearance. Relative to no missed school days, there was a significant mean increase of 57% (incidence rate ratio, 1.57; 95% CI, 1.52-1.62) in time to full unrestricted clearance for 3 or more missed school days. The estimated mean days to return to sport were 12.15 (95% CI, 12.00-12.30) for 0 missed school days, 12.68 (95% CI, 12.39-12.96) for 1 missed school day, 15.47 (95% CI, 15.06-15.87) for 2 missed school days, and 19.08 (95% CI, 18.55-19.62) for 3 or more missed school days.

Conclusions and Relevance

This cohort study found that high school athletes typically missed 2 or fewer school days after SRC, suggesting that concussion management teams adhered to current recommendations of 24 to 48 hours of initial rest. The dose association, with more missed school days associated with slower return to play, suggests athletes' missing more school days (eg, ≥3) may be associated with severity of concussion and warrant additional support to return to school and/or sport.

Position comparison of sport-related concussions in female youth soccer players

OBJECTIVES

Youth soccer participation, particularly among females, continues to grow worldwide. With the high incidence of sport-related concussion (SRC) in soccer, it is important to investigate if SRC occurs disproportionally by positions. Our hypothesis was to see no positional differences in SRCs, SRC-related characteristics, and outcomes among in female youth soccer athletes.

METHODS

Data were prospectively collected from participants at a single sports medicine institution between August 2015-April 2021. Female participants aged 8-18 diagnosed with SRC sustained during an organized soccer practice, scrimmage, or game were separated into 4 groups based on position: Forward, Midfielder, Defender, and Goalkeeper. Demographics, medical history, injury-related details, and outcomes were reviewed. A chi-square test or Fisher's exact test was used for categorical variables. Continuous variables were compared with Mann-Whitney or Kruskal-Wallis test.

RESULTS

Two hundred fourteen participants were included: 52 Forwards, 65 Midfielders, 63 Defenders, and 34 Goalkeepers. There were no significant differences between the groups in age, race, ethnicity, or previous concussion history. Differences in mechanism existed with Goalkeepers most commonly reporting Head to Body Part. Goalkeepers, which make up 1/11 of the total positions on the field, had a significantly higher proportion of SRCs compared to Field Positions. (9.1% vs 15.9%)At 3-month post-enrollment, there were no significant differences in reported symptoms or return-to-play between the different positions.

CONCLUSION

In youth female soccer players, goalkeepers sustained a higher proportion of sport-related concussions compared to field players based upon the composition of a soccer team. The mechanism of injury also differed among the different soccer positions. However, no differences in concussion characteristics, outcomes, or RTP were seen across the different soccer positions.

Hormonal Contraceptive Influence on Baseline Vestibular/Ocular Symptomatology and Provocation for Concussion

Background

Hormonal contraceptives (HCs) and the menstrual cycle have been suggested to affect symptom severity and postconcussion recovery. Additionally, hormones have been a suggested rationale for sex differences between female and male athletes on concussion assessment. Researchers have yet to explore the effects of HC use on baseline symptomatology, including symptom reporting and provocation.

Purpose

To examine the influence of HC use on a baseline symptom reporting and vestibular/ocular provocation battery.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 61 college-aged individuals (21 HC-using women, 21 non-HC-using women, 19 men) were administered a baseline symptom battery consisting of the Post-Concussion Symptom Scale (PCSS), Headache Impact Test-6 (HIT-6), Pediatric Vestibular Symptom Questionnaire (PVSQ), and Vestibular/Ocular Motor Screening (VOMS). The main outcome measures consisted of PCSS symptom reporting (total symptoms, symptom severity score, and symptom factors), HIT-6 and PVSQ total scores, and VOMS item (ie, saccades, convergence, or vestibular/ocular reflex) symptom provocation scores.

Results

Significant differences were reported on HIT-6, with the highest headache reporting in the HC group (P = .026). On the PVSQ, the HC group also reported greater dizziness and unsteadiness symptoms than the non-HC group (P = .023). Similar findings existed on the PCSS, with the HC group reporting greater total symptoms (P < .001), symptom severity (P < .001), and vestibular-somatic (P = .024), cognitive-sensory (P = .004), sleep-arousal (P = .001), and affective (P < .001) factors compared with the non-HC group. Smooth pursuit (ie, following finger smoothly with eyes) was the only VOMS items with differences between groups (P = .003), with the HC group having greater provocation compared with non-HC users (P = .020).

Conclusion

HC use was associated with overall symptomatology and worse self-reported symptoms on vestibular-related inventories and concussion symptom scales and factors when compared with non-HC users and male controls. Additionally, HC users reported higher VOMS provocation scores on the smooth pursuit item than non-HC users and male controls.

Sex Differences in Resource Allocation and Access to Care After Sport-Related Concussion

CONTEXT

After sport-related concussion (SRC), immediate access to a certified athletic trainer (AT) is important to ensure proper treatment. However, resource allocation and coverage may differ between male and female youth sports.

OBJECTIVE

To compare resource allocation between male and female sports in the following areas: (1) rates of immediate on-field evaluation by an AT at the time of injury, (2) time to general health care presentation, and (3) time to SRC clinic presentation.

DESIGN

Retrospective cohort study.

SETTING

Regional sports concussion center.

PATIENTS OR OTHER PARTICIPANTS

Athletes aged 14 to 18 years who presented to a regional sports concussion center from November 2017 to April 2022.

MAIN OUTCOME MEASURE(S)

The primary exposure of interest was sex (male or female). The primary outcome was immediate on-field evaluation by an AT (yes or no). Secondary outcomes included time to general health care and SRC clinic presentation. Descriptive statistics, χ2 analyses, and linear regressions were performed. Covariates included age, history of prior concussions, and statistically significant demographics.

RESULTS

A total of 832 patients with SRC were included (age = 16.2 ± 1.2 years, 66.5% male). Female athletes had lower rates of attention-deficit/hyperactivity disorder (χ2 = 10.404, P = .001) and higher rates of anxiety and depression (χ2 = 12.891, P < .001) compared with male athletes. The average time to presentation to general health care and the SRC clinic did not differ between males and females, but AT on-field evaluation occurred more in male (40.3%) than female (32.3%) athletes (χ2 = 8.677, P = .013). Multivariable linear regression found that AT on-field evaluation was a significant predictor of time to general health care presentation (β = -.085, P = .015) but not SRC clinic presentation (β = -.055, P = .099). History of prior concussions was a significant predictor of time to initial health care contact (β = .083, P = .018). History of anxiety and depression (β = .136, P < .001) and initial evaluation by emergency department or urgent care (β = .305, P < .001) were significant predictors of delayed time to SRC clinic presentation.

CONCLUSIONS

Among 832 concussed youth athletes, female athletes were evaluated less frequently by an AT immediately after injury. Furthermore, not being evaluated by an AT on field was significantly associated with a longer time to health care presentation. Future investigations should elucidate resource equity among male and female athletes.

Association of Alzheimer's disease polygenic risk score with concussion severity and recovery metrics

Identification of genetic alleles associated with both Alzheimer's disease (AD) and concussion severity/recovery could help explain the association between concussion and elevated dementia risk. However, there has been little investigation into whether AD risk genes associate with concussion severity/recovery, and the limited findings are mixed. We used AD polygenic risk scores (PRS) and APOE genotypes to investigate any such associations in the NCAA-DoD Grand Alliance CARE Consortium (CARE) dataset. We assessed six outcomes in 931 total participants. The outcomes were two concussion recovery measures (number of days to asymptomatic status, number of days to return to play (RTP)) and four concussion severity measures (scores on SAC and BESS, SCAT symptom severity, and total number of symptoms). We calculated PRS using a published score [1] and performed multiple linear regression (MLR) to assess the relationship of PRS with the outcomes. We also used t-tests and chi-square tests to examine outcomes by APOE genotype, and MLR to analyze outcomes in European and African genetic ancestry subgroups. Higher PRS was associated with longer injury to RTP in the normal RTP (<24 days) subgroup ( p = 0.024), and one standard deviation increase in PRS resulted in a 9.89 hour increase to the RTP interval. There were no other consistently significant effects, suggesting that high AD genetic risk is not strongly associated with more severe concussions or poor recovery in young adults. Future studies should attempt to replicate these findings in larger samples with longer follow-up using PRS calculated from diverse populations.

High school rugby coaches' knowledge and opinions of concussion in Kwa-Zulu Natal province in South Africa: an ecological cross-sectional study

BACKGROUND

Concussions in Rugby Union are common with an increased risk to adolescent players. Coaches are key to injury prevention and a greater understanding of their knowledge and sentiments may guide future initiatives. There is a lack of data on rugby coaches, especially in South Africa. This study aimed to investigate the knowledge and opinions of high school rugby coaches regarding concussion management.

METHODS

This cross-sectional study of 37 high school rugby coaches in South Africa, was conducted via a self-reported questionnaire. Concussion knowledge was scored for correct answers only with closed-question scaling methods to measure the importance of items of concussion management using a graphical rating scale. An attitude scale (Likert) was used to assess self-reported opinions and behaviours. Associations were calculated for participant characteristics and overall concussion injury knowledge.

RESULTS

More participants showed good overall knowledge of ≥ 75% (n = 22, 59% vs. n = 15, 40%), especially those with greater coaching experience (p = 0.021). Player welfare was perceived more important than player performance (185 vs. 164), with concussion prevention most important (184 of 185). Appealing characteristics of an injury prevention programme were the improvement of player skill (173, SD ± 0.75, mean 4.68), being adaptable (171, ± 0.86, 4.62), and being completed in the warm-up (167, ± 0.93, 4.51). The biggest perceived barriers were duration (138, ± 1.59, mean 3.73), effort (130, ± 1.56, 3.51), compliance and lack of knowledge (both 127, ± 1.68, 3.43).

CONCLUSION

These results support the implementation of ongoing concussion education for rugby coaches and identify areas for promoting awareness and knowledge of concussion injury prevention, identification, and specific management of younger athletes. Appealing characteristics and barriers are highlighted and may allow for improved implementation and adherence to concussion prevention programmes.

Differences in Injury Profiles Between Female and Male Athletes Across the Participant Classification Framework: A Systematic Review and Meta-Analysis

BACKGROUND

Female sex is a significant determinant of anterior cruciate ligament (ACL) injury. It is not understood if sex is a key determinant of other sports-related injuries.

OBJECTIVE

The aim of this systematic review was to identify where differences in injury profiles are most apparent between the sexes in all sports across the six-tiered participant classification framework.

METHODS

This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and the 'implementing PRISMA in Exercise, Rehabilitation, Sport medicine and SporTs science'(PERSiST) guidance. The databases PubMed, CINAHL, Web of Science, SPORTDiscus, Medline, Scopus, Cochrane Library and EBSCO were searched from database inception to 24 April 2023. Longitudinal, prospective and retrospective cohort studies and cross-sectional and descriptive epidemiology studies that used standard injury data collection were included. Studies were excluded if injuries were not medically diagnosed and if injuries were not reported and/or analysed by sex. Two reviewers independently extracted data and assessed study quality using the Downs and Black checklist.

RESULTS

Overall, 180 studies were included (8 tier-5, 40 tier-4, 98 tier-3, 30 tier-2, 5 tier-1 studies; one study included data in two tiers). Of those, 174 studies were of moderate quality and six studies were of limited quality. In sex-comparable sports, there was moderate evidence that female athletes had greater risk of knee injury (relative risk (RR) 2.7; 95% CI 1.4-5.5), foot/ankle injuries (RR 1.25; 95% CI 1.17-1.34), bone stress injury (RR 3.4; 95% CI 2.1-5.4) and concussion (RR 8.46; 95% CI 1.04-68.77) than male athletes. Male athletes were at increased risk of hip/groin injuries (RR 2.26; 95% CI 1.31-3.88) and hamstring injuries (RR 2.4; 95% CI 1.8-3.2) compared with females, particularly in dynamic sports. Male athletes were 1.8 (1.37-2.7) to 2.8 (2.45-3.24) times more likely to sustain acute fractures than female athletes, with the highest risk in competition.

DISCUSSION

Most studies in all cohorts were of moderate quality (mean/range of scores tier-5: 17 ± 2.2 [14-20], tier-4: 16.9 ± 1.9 [11-21], tier-3: 16.9 ± 1.5 [11-20], tier-2: 16.3 ± 2.2 [11-20], tier-1 studies: 15.6 ± 1.3 [14-17] out of 28 on the Downs and Black checklist), with only six studies of limited quality. Female athletes' propensity for bone stress injuries highlights opportunities to reinforce development of optimal bone health during adolescence and to outline the effects of energy availability. Earlier strength development and exposure to neuromuscular training programmes and modification of skill development in female athletes may be effective strategies for reducing lower limb injury risk. Key components of neuromuscular training programmes could be beneficial for reducing hip/groin and hamstring injury risk in male athletes. There may be a need for sex-specific prevention and return-to-sport protocols for sports-related concussion in female athletes.

CONCLUSIONS

Female sex was a key determinant of sports-related injuries beyond ACL injury including foot/ankle injury, bone stress injury and sports-related concussion. Male sex was a key determinant of hip/groin, hamstring injury and upper limb injury.

TRIAL REGISTRY

PROSPERO registration number: CRD42017058806 (last updated on 7th June 2023).

Postconcussion Moderate to Vigorous Physical Activity Predicts Anxiety Severity among Adolescent Athletes

PURPOSE

This study aimed to examine how moderate-to-vigorous physical activity (MVPA) during concussion recovery influences self-reported anxiety symptoms at follow-up assessment. We hypothesized that more MVPA after concussion would be associated with lower anxiety rating at follow-up.

METHODS

We performed a prospective study of participants aged 13-18 yr initially assessed within 14 d of diagnosed concussion. Participants rated concussion symptoms using the Post-Concussion Symptom Inventory and were provided a wrist-worn actigraphy device to track activity for 1 wk after assessment. At follow-up assessment, participants rated anxiety symptoms using the four-question Patient-Reported Outcomes Measurement Information System (PROMIS) anxiety subscale. Each question ranged from 1 (never) to 5 (almost always), with an overall score range of 4-20. For univariable analysis, we calculated correlation coefficients between MVPA and PROMIS anxiety subscale scores. We then created a multiple linear regression model with follow-up PROMIS anxiety subscale score as the outcome and MVPA, sex, initial symptom severity, and preconcussion anxiety as predictors.

RESULTS

We enrolled and initially tested 55 participants, and 48 were included in the final analysis (age, 14.6±2.7 yr; 56% female; initial assessment, 7.3± 3.1 d; follow-up assessment, 42.0±29.7 d). We observed an inverse and low correlation between MVPA and follow-up PROMIS anxiety subscale T-scores ( r = -0.30, P = 0.04). Multivariable regression results indicated that MVPA ( β = -5.30; 95% confidence interval (CI), -10.58 to -0.01), initial Post-Concussion Symptom Inventory score ( β = 0.11; 95% CI, 0.03 to 0.19), and preconcussion anxiety ( β = 5.56; 95% CI, 0.12 to 11.0), but not sex ( β = -2.60; 95% CI, -7.14, to 1.94), were associated with follow-up PROMIS anxiety subscale T-scores.

CONCLUSIONS

After adjusting for covariates, more MVPA early after concussion predicted lower PROMIS anxiety subscale scores at follow-up. Although initial concussion symptom severity and preconcussion anxiety were also associated with follow-up PROMIS anxiety subscale score, MVPA represents a modifiable factor that may contribute to lower anxiety symptoms.

A developmental framework for understanding the influence of sex and gender on health: Pediatric pain as an exemplar

Sex differences are a robust finding in many areas of adult health, including cardiovascular disease, psychiatric disorders, and chronic pain. However, many sex differences are not consistently observed until after the onset of puberty. This has led to the hypothesis that hormones are primary contributors to sex differences in health outcomes, largely ignoring the relative contributions of early developmental influences, emerging psychosocial factors, gender, and the interaction between these variables. In this paper, we argue that a comprehensive understanding of sex and gender contributions to health outcomes should start as early as conception and take an iterative biopsychosocial-developmental perspective that considers intersecting social positions. We present a conceptual framework, informed by a review of the literature in basic, clinical, and social science that captures how critical developmental stages for both sex and gender can affect children's health and longer-term outcomes. The literature on pediatric chronic pain is used as a worked example of how the framework can be applied to understanding different chronic conditions.

Acute Sport-Related Concussion Management and Return to Sport Time in High School Athletes

BACKGROUND

The current evidence for acute management practices of sport-related concussion (SRC) is often limited to in-clinic visits, with limited studies identifying professionals in early SRC care and the association with prolonged recovery outcomes.

PURPOSE

To describe acute SRC management practices (ie, the personnel in the initial evaluations, removal from activity) and test the association with prolonged return to sport (RTS) time.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

We conducted a retrospective cohort study of 17,081 high school SRCs accrued between the 2015-2016 and 2020-2021 academic years. We reported acute management practices and RTS time as frequencies stratified by sex, sport, and event type and compared athletic trainer (AT) access in initial evaluation with chi-square tests (P < .05). Separate logistic regressions estimated odds ratios (ORs) and 95% CIs for removal from activity and prolonged RTS >21 days by acute management practices.

RESULTS

Most SRCs (n = 12,311 [72.1%]) had complete initial evaluation by an AT. Boys had an AT evaluation in 75.5% (n = 2860/3787) of practice-related and 74.8% (n = 5551/7423) of competition-related events. Girls had an AT evaluation in 61.3% (n = 1294/2110) of practice-related and 69.3% (n = 2606/3761) of competition-related events. In sex-comparable sports (n = 6501), there was no difference between boys (n = 1654/2455 [67.4%]) and girls (n = 2779/4046 [68.7%]) having an AT involved in the first evaluation (χ2 = 1.21; P = .27). Notably, 25.3% of girls' SRCs were evaluated by a coach alone, and we observed differences in personnel in initial evaluations by sport. The odds of immediate removal were higher when an AT made the initial evaluation (OR, 2.8 [95% CI, 2.54-3.08]). The odds of prolonged RTS >21 days was lower for those with an AT in the initial evaluation (OR, 0.74 [95% CI, 0.65-0.84]) adjusting for significant factors from univariate analyses, boys relative to girls (OR, 0.85 [95% CI, 0.76-0.96]), specialty care relative to PCP (OR, 2.16 [95% CI, 1.90-2.46]), specialty care relative to urgent or ready care (OR, 0.99 [95% CI, 0.82-1.22]) concussion history (OR, 1.41 [95% CI, 1.22-1.63]), and removal from activity (OR, 0.90 [95% CI, 0.78-1.05]).

CONCLUSION

This study found variability in personnel involved in initial SRC evaluations, with higher percentages of athletes with SRCs having ATs make the initial evaluation during competitive events. There was no association between sex and AT involvement in comparable sports. There was an association between prolonged RTS and AT involvement, sex, concussion history, and location of follow-up care.

Sex-Biased Expression and Response of microRNAs in Neurological Diseases and Neurotrauma

Neurological diseases and neurotrauma manifest significant sex differences in prevalence, progression, outcome, and therapeutic responses. Genetic predisposition, sex hormones, inflammation, and environmental exposures are among many physiological and pathological factors that impact the sex disparity in neurological diseases. MicroRNAs (miRNAs) are a powerful class of gene expression regulator that are extensively involved in mediating biological pathways. Emerging evidence demonstrates that miRNAs play a crucial role in the sex dimorphism observed in various human diseases, including neurological diseases. Understanding the sex differences in miRNA expression and response is believed to have important implications for assessing the risk of neurological disease, defining therapeutic intervention strategies, and advancing both basic research and clinical investigations. However, there is limited research exploring the extent to which miRNAs contribute to the sex disparities observed in various neurological diseases. Here, we review the current state of knowledge related to the sexual dimorphism in miRNAs in neurological diseases and neurotrauma research. We also discuss how sex chromosomes may contribute to the miRNA sexual dimorphism phenomenon. We attempt to emphasize the significance of sexual dimorphism in miRNA biology in human diseases and to advocate a gender/sex-balanced science.

Are Sex Differences in Collegiate and High School Sports-Related Concussion Reflected in the Guidelines? A Scoping Review

Background: Sport-related concussion (SRC) is a common sport injury. Females are participating in sports at increasing rates, and there is growing awareness that female athletes may be more vulnerable to SRC. Objectives: We aimed to identify sex differences in epidemiology, clinical manifestation and assessment of SRC and examine how these relate to the 6th International Conference on Concussion in Sport (ICCS). Methods: We conducted a scoping review of the Medline database and identified 58 studies examining the effects of sex on SRC in collegiate and high school athletes that were written in English and published in a peer-reviewed journal between March 2012 and March 2022. Results: We found that female athletes suffer higher rates of concussion in sex-comparable sports, in particular soccer. Female athletes experience more somatic symptoms-headache/migraine/sleep disturbance-and may take longer to recover from concussion. Sex differences were also identified regarding some aspects of sideline concussion assessment with the Sport Concussion Assessment Tool. Conclusions: Females are at greater risk and experience SRC differently than males; this is mostly likely due to a combination of biomechanical factors, differences in neck musculature and hormonal and social factors. Sex differences are not widely addressed by the 6th ICSS, which informs many sports' concussion protocols.

The consideration of post-exercise impact on SCAT3 scores in athletes immediately following a head injury

METHODS

Symptoms were assessed immediately following completion of a rugby match (median 60 minutes). Players removed from the match for assessment due to a head hit were classified as head injured. Controls completed match without head hit.

RESULTS

209 players (67 female; 33 ± 13 years) participated with 80 experiencing a head injury. Symptom severity was significantly greater in head injured (26.2 ± 17.6) compared with controls (8.9 ± 11.5, P < 0.001). 21% of control players reporting >16 symptom severity, misclassifying them as suspected concussion. There were no significant sex differences. Factor analysis produced four symptom clusters of which Headache was most discriminatory between the head injured (median = 1.7) and controls (median = 0.0).

CONCLUSION

These findings demonstrate that exercise and contact during a game affect symptom assessment, increasing the likelihood of misclassifying players with suspected concussion. Factor characterization of symptoms associated with head injury using an exercised comparison group provides more useful discrimination. These results highlight the necessity for objective measures to diagnose concussions outside of symptom self-report.

Comparison of Volleyball-Related Injuries at US Emergency Departments Between High School and Collegiate Athletes: A 10-Year NEISS Database Study

Background

There is a paucity of current data regarding the sport-specific injury patterns and epidemiological trends associated with volleyball.

Purpose

To provide an updated, comparative assessment of the epidemiology of volleyball-related injuries among female high school- and college-aged athletes and to characterize the burden of these injuries on emergency departments (EDs) across the United States.

Study Design

Descriptive epidemiological study.

Methods

Data were obtained from the National Electronic Injury Surveillance System for volleyball-related injuries between 2012 and 2021 in high school-aged (14-18 years) and college-aged (19-23 years) patients. Incidence, injury characteristics, incident locales, and dispositions were analyzed with weighted population statistics based on National Federation of State High School Associations and National Collegiate Athletic Association data as well as incidence rates and incidence rate ratios (IRRs) and 95% CIs.

Results

In total, an estimated 214,302 female athletes aged 14 to 23 years were evaluated in EDs across the United States with volleyball-related injuries between 2012 and 2021. Female college-aged athletes were nearly 3 times more likely to be evaluated with these injuries than their high school-aged counterparts, with incidence rates of 12.8 per 100 at-risk individuals among college-aged athletes and 4.3 per 100 at-risk individuals in high school-aged athletes (IRR, 0.338; 95% CI, 0.333-0.342). The ankle, head, and knee were most frequently injured, often involving strains/sprains, contusions, fractures, and concussions. The IRRs of nearly all injuries were higher among collegiate athletes, especially among knee (IRR, 4.56; 95% CI, 4.40-4.72) and shoulder (IRR, 5.07; 95% CI, 4.81-5.35) injuries.

Conclusion

Among volleyball-related injuries evaluated in EDs between 2012 and 2021, the incidence rates of injuries in college-aged athletes far surpassed those of their high school-aged peers irrespective of injury type or bodily location. While sprains and strains were the most frequent injuries, head injuries accounted for the second most common diagnosis in both groups, suggesting that clinicians should maintain a high index of suspicion for concussion when evaluating players.

Clinical recovery from concussion-return to school and sport: a systematic review and meta-analysis

OBJECTIVE

To define the time frames, measures used and modifying factors influencing recovery, return to school/learn (RTL) and return to sport (RTS) after sport-related concussion (SRC).

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

8 databases searched through 22 March 2022.

ELIGIBILITY CRITERIA

Studies with diagnosed/suspected SRC and interventions facilitating RTL/RTS or investigating the time and modifying factors for clinical recovery. Outcomes included days until symptom free, days until RTL and days until RTS. We documented study design, population, methodology and results. Risk of bias was evaluated using a modified Scottish Intercollegiate Guidelines Network tool.

RESULTS

278 studies were included (80.6% cohort studies and 92.8% from North America). 7.9% were considered high-quality studies, while 23.0% were considered high risk of bias and inadmissible. The mean days until symptom free was 14.0 days (95% CI: 12.7, 15.4; I²=98.0%). The mean days until RTL was 8.3 (95% CI: 5.6, 11.1; I²=99.3%), with 93% of athletes having a full RTL by 10 days without new academic support. The mean days until RTS was 19.8 days (95% CI: 18.8, 20.7; I²=99.3%), with high heterogeneity between studies. Several measures define and track recovery, with initial symptom burden remaining the strongest predictor of longer days until RTS. Continuing to play and delayed access to healthcare providers were associated with longer recovery. Premorbid and postmorbid factors (eg, depression/anxiety, migraine history) may modify recovery time frames. Though point estimates suggest that female sex or younger age cohorts take longer to recover, the heterogeneity of study designs, outcomes and overlap in CIs with male sex or older age cohorts suggests that all have similar recovery patterns.

CONCLUSION

Most athletes have full RTL by 10 days but take twice as long for an RTS.

PROSPERO REGISTRATION NUMBER

CRD42020159928.

Youth Tackle Football Head-Impact Estimation by Players and Parents: Is the Perception the Reality?

CONTEXT

With growing concerns surrounding exposure to head impacts in youth tackle football, players and parents must understand the exposure level when assenting and consenting to participate.

OBJECTIVE

To determine whether youth football players and parents could estimate on-field head-impact frequency, severity, and location.

DESIGN

Prospective cohort study.

SETTING

Football field.

PATIENTS OR OTHER PARTICIPANTS

We administered a 10-question head-impact estimation tool to parents (n = 23; mean age = 36.5 years [95% CI = 31.7, 37.3 years]) and players (n = 16 boys; mean age = 11.1 years [95% CI = 10.3, 11.8 years]).

MAIN OUTCOME MEASURE(S)

Player on-field head-impact exposure was captured using the Triax SIM-G system. We determined the accuracy between player and parent estimates relative to on-field head-impact exposures using κ and weighted κ values.

RESULTS

Youth tackle football players and parents did not accurately estimate on-field head-impact frequency (κ range = -0.09 to 0.40), severity (κ range = -0.05 to 0.34), or location (κ range = -0.30 to 0.13). Players and parents overestimated head-impact frequency in practices but underestimated the frequency in games. Both groups overestimated head-impact severity, particularly in games. Most players and parents underestimated the number of head impacts to the top of the head, particularly during practices.

CONCLUSIONS

Underestimations of head-impact frequency in games and to the top of the head suggest that informed consent processes aimed at educating players and parents should be improved. Overestimations of head-impact frequency in practices and severity may explain declining rates of youth tackle football participation.

Higher Sedentary Behaviors and Lower Levels of Specific Knowledge Are Risk Factors for Physical Activity-Related Injuries in Saudi Adolescents

Encouraging physical activity (PA) for adolescents is necessary to achieve and maintain optimal health, but it may increase the risk of PA-related injuries. This study sought to assess the frequency, location, type, and severity of PA-related injuries in Saudi students aged 13 to 18 years and to identify associated risk factors. A total of 402 students, including 206 boys aged 15.87 ± 1.69 years and 196 girls aged 15.83 ± 1.70 years, were randomly assigned to participate in this study. For each participant, height, weight, body mass index, and fat percentage were measured. Responses to a specially designed four-part self-administered questionnaire were also collected. Results revealed that better specific knowledge was associated with a lower likelihood of sustaining injuries (β = -0.136; p = 0.001) but increased sedentary behaviors were associated with a greater likelihood of sustaining a PA-related injury (β = 0.358; p = 0.023). Gender, knowledge, and sedentary behaviors were the factors overall associated with a greater likelihood of suffering 1, 2, and 3 or more PA-related injuries. However, gender, fat-free mass, knowledge, and sedentary behaviors were associated overall with a greater likelihood of bruises, strains, fractures, sprains, concussions, and at least two types of PA-related injuries. Collectively, we should pay attention to the PA-related injury problem among middle and high school students, particularly when promoting a physically active lifestyle.

Median Time to Return to Sports After Concussion Is Within 21 Days in 80% of Published Studies

PURPOSE

To perform a systematic review of the literature and evaluate the return to play (RTP) time frame after a concussion diagnosis. Our secondary purpose was to analyze and compare different prognostic variables affecting concussions, time to return to school, time to symptom resolution of concussive symptoms, and time each patient spent in the RTP protocol.

METHODS

A PubMed, Scopus, Medline, Embase, and Cochrane Library database literature review was performed in August 2022. The studies needed to report, in days, the length of time a patient/athlete was removed from play due to concussion management. The Risk of Bias in Non-Randomized Studies of Interventions tool was used for risk of bias for each study, and Methodological Index for Non-Randomized Studies criteria were used for quality assessment.

RESULTS

There were 65 studies included in the systematic review and a total of 21,966 patients evaluated. The RTP time intervals ranged from 1 to 1,820 days, with 80.7% of the median RTP time frames for each study within 21 days. Preconcussion risk factors for prolonged RTP included female sex, younger age, presence of psychiatric disorders, and history of previous concussion. Postconcussion risk factors included severe symptom scores at initial clinic visit, loss of consciousness, nonelite athletes, and delayed removal from competition. The most common sports resulting in concussion were contact sports, most commonly football and soccer. Median time to return to school was 3 to 23 days. Median time to symptom resolution ranged from 2 to 11 days. Median time in RTP protocol was 1 to 6 days.

CONCLUSIONS

Median time to return to sports after concussion is within 21 days in 80% of published studies.

LEVEL OF EVIDENCE

IV, systematic review of Level I to IV studies.

Neurovascular hypoxia after mild traumatic brain injury in juvenile mice correlates with heart-brain dysfunctions in adulthood

AIM

Retrospective studies suggest that mild traumatic brain injury (mTBI) in pediatric patients may lead to an increased risk of cardiac events. However, the exact functional and temporal dynamics and the associations between heart and brain pathophysiological trajectories are not understood.

METHODS

A single impact to the left somatosensory cortical area of the intact skull was performed on juvenile mice (17 days postnatal). Cerebral 3D photoacoustic imaging was used to measure the oxygen saturation (sO₂ ) in the impacted area 4 h after mTBI followed by 2D and 4D echocardiography at days 7, 30, 90, and 190 post-impact. At 8 months, we performed a dobutamine stress test to evaluate cardiac function. Lastly, behavioral analyses were conducted 1 year after initial injury.

RESULTS

We report a rapid and transient decrease in cerebrovascular sO₂ and increased hemoglobin in the impacted left brain cortex. Cardiac analyses showed long-term diastolic dysfunction and a diminished systolic strain response under stress in the mTBI group. At the molecular level, cardiac T-p38MAPK and troponin I expression was pathologic modified post-mTBI. We found linear correlations between brain sO₂ measured immediately post-mTBI and long-term cardiac strain after 8 months. We report that initial cerebrovascular hypoxia and chronic cardiac dysfunction correlated with long-term behavioral changes hinting at anxiety-like and memory maladaptation.

CONCLUSION

Experimental juvenile mTBI induces time-dependent cardiac dysfunction that corresponds to the initial neurovascular sO₂ dip and is associated with long-term behavioral modifications. These imaging biomarkers of the heart-brain axis could be applied to improve clinical pediatric mTBI management.

Sport-related concussion disclosure in women's rugby-A social identity approach

Introduction

Sport-related concussion (SRC) is a risk of collision sports such as women's rugby. To support appropriate SRC diagnosis and management, an understanding of the factors that encourage SRC disclosure is necessary. To date, research has focused on ascertaining individual player knowledge and attitudes towards SRC disclosure.

Methods

We chose to investigate the potential influence of group identification effects by examining the role of social identity on SRC disclosure in elite women's rugby. Seventeen elite players from the United Kingdom and Ireland were interviewed and their transcripts thematically analysed.

Results

The data highlighted that the players shared a very strong social identity as women in rugby and were acutely aware that their experiences were different to their male counterparts. The shared social identity had both positive and negative implications for SRC disclosure. The players interviewed did not feel comfortable disclosing their symptoms to their coach and often felt that medical staff either did not listen to them or were unavailable to them. Mediators such as communication, trust in medical teams, perceived pressure, positive injury management experience, and player role models were identified.

Discussion

This research could be utilised to inform sport psychology interventions to enhance SRC disclosure in elite women's rugby.

Concussion increases within-player injury risk in male professional rugby union

OBJECTIVES

To assess within-player change in injury risk and between-player subsequent injury risk associated with concussive and common non-concussive injuries in professional rugby union.

METHODS

This prospective cohort study in Welsh professional male rugby union analysed within-player and between-player injury risk for five common injuries: concussion, thigh haematoma, hamstring muscle strain, lateral ankle sprain and acromioclavicular joint sprain. Survival models quantified within-player injury risk by comparing precommon (before) injury risk to postcommon (after) injury risk, whereas between-player subsequent injury risk was quantified by comparing players who had sustained one of the common injuries against those who had not sustained the common injury. HRs and 95% CIs were calculated. Specific body area and tissue type were also determined for new injuries.

RESULTS

Concussion increased the within-player overall injury risk (HR 1.26 (95% CI 1.11 to 1.42)), elevating head/neck (HR 1.47 (95% CI 1.18 to 1.83)), pelvic region (HR 2.32 (95% CI 1.18 to 4.54)) and neurological (HR 1.38 (95% CI 1.08 to 1.76)) injury risk. Lateral ankle sprains decreased within-player injury risk (HR 0.77 (95% CI 0.62 to 0.97)), reducing head/neck (HR 0.60 (95% CI 0.39 to 0.91)), upper leg and knee (HR 0.56 (95% CI 0.39 to 0.81)), joint and ligament (HR 0.72 (95% CI 0.52 to 0.99)) and neurological (HR 0.55 (95% CI 0.34 to 0.91)) injury risk. Concussion (HR 1.24 (95% CI 1.10 to 1.40)), thigh haematomas (HR 1.18 (95% CI 1.04 to 1.34)) and hamstring muscle strains (HR 1.14 (95% CI 1.01 to 1.29)) increased between-player subsequent injury risk.

CONCLUSION

Elevated within-player injury risk was only evident following concussive injuries, while lateral ankle sprains reduced the risk. Both concussion and ankle injuries altered head/neck and neurological injury risk, but in opposing directions. Understanding why management of ankle sprains might be effective, while current concussion management is not at reducing such risks may help inform concussion return to play protocols.

Repetitive bout of controlled soccer heading does not alter heart rate variability metrics: A preliminary investigation

Objectives

There is elevated unease regarding how repetitive head impacts, such as those associated with soccer heading, contribute to alterations in brain function. This study examined the extent heart rate variability (HRV) and cardiac baroreceptor sensitivity (BRS) metrics are altered immediately following an acute bout of soccer heading.

Methods

Seven male elite soccer players (24.1 ± 1.5 years) completed 40 successful soccer headers in 20-min. The headers were performed under controlled circumstances using a soccer ball launcher located 25 meters away and using an initial ball velocity of 77.5 ± 3.7 km/h (heading condition). An accelerometer (xPatch) on the right mastoid process quantified linear/rotational head accelerations. Participants also completed sham (body contact) and control (non-contact) sessions. A three-lead ECG and finger photoplethysmography characterized short-term spontaneous HRV/cardiac BRS, before and after each condition. The SCAT3 indexed symptom scores pre-post exposures to all three conditions.

Results

During the heading condition, cumulative linear and rotational accelerations experienced were 1,574 ± 97.9 g and 313,761 ± 23,966 rad/s², respectively. Heart rate trended toward an increase from pre- to post-heading (p = 0.063), however HRV metrics in the time-domain (ps > 0.260) and frequency-domain (ps > 0.327) as well as cardiac BRS (ps > 0.144) were not significantly changed following all three conditions. Following the heading condition, SCAT3 symptom severity increased (p = 0.030) with a trend for symptom score augmentation (p = 0.078) compared to control and sham.

Conclusion

Whereas, symptoms as measured by the SCAT3 were induced following an acute bout of controlled soccer heading, these preliminary findings indicate they were not accompanied by alterations to autonomic function. Ultimately, this demonstrates further research is needed to understand the physiological underpinnings of alterations in brain function occurring immediately after a bout of soccer heading and how these may, over time, contribute to long-term neurological impairments.

Prevalence of Acute Neck Pain Following Sports-Related Concussion in High School Athletes

OBJECTIVES

To explore the prevalence of acute neck pain in high school athletes following sports-related concussion (SRC) and to examine the role of acute neck pain in modifying or amplifying concurrent concussive symptoms.

DESIGN

Retrospective observational.

SETTING

High school sporting events.

PARTICIPANTS

High school athletes who suffered a sports-related concussion between the 2011 and 2019 academic years academic years from the National Athletic Treatment, Injury and Outcomes Network (NATION) Study.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Prevalence of neck pain (yes/no) along with 33 other commonly reported concussion symptoms, number of symptoms reported, mechanism of injury (contact with person/surface or object), sport type (contact/noncontact), and injury history (first time/repeated injury).

RESULTS

One hundred thirty-eight of 401 athletes (33.9%) indicated acute neck pain following SRC. Those with neck pain reported significantly more symptoms overall (M = 13.53, SD = 6.89) relative to their non-neck pain counterparts (M = 8.46, SD = 5.68; t [191.35] = 7.11, P < 0.001). Athletes with SRC due to contact with a surface were significantly less likely to report neck pain than those reported contact with a person. Neck pain, repeated injury, and female sex were significantly associated with a greater number of concussion symptoms in the acute phase.

CONCLUSIONS

Our data suggest that acute neck pain is a frequent acute symptom following SRC and signals the necessity for additional screening to seek and identify comorbid cervical pathology. Prospective studies should seek to access the benefit of cervical therapy in the early stages in SRC patients with neck pain to reduce the risk of persistent postconcussion symptoms.

Cross-sectional study of gender differences in physical activity-related injuries amongst Chinese college students majoring in rehabilitation

The main objective of the paper was to explore the potential risk factors for physical activity-related injuries (PARI) amongst college students majoring in rehabilitation and to analyse gender differences. A random whole group sampling method was used to recruit freshmen to seniors aged 15-25 years from over 90 universities in China that offer rehabilitation. The total number of people included was 6,032, of which 1,989 were male and 4,043 were female. The underlying risk factors for PARI of different genders were assessed using a structured self-management questionnaire including sociodemographic characteristics, physical activity levels, risk-taking and protective behaviors, and PARI. Totally 6,032 questionnaires were obtained for final analysis, with 792 total number of injured persons (415 males, 377 females), the sum of the cumulative frequency of injuries to injured persons is 1,607 (881 males, 726 females) and a PARI risk of 0.27 (males: 0.44, females: 0.18; p < 0.001; sum of the cumulative frequency of injuries/total number of people surveyed/year). For male and female students, participation in sports teams, having a high level of PA as well as with antisocial behavior were risk factors for developing PARI. Regarding female students, regional differences was associated with elevated odds to suffer from PARI. The prevalence rates of PARI vary between male and female students. The research subjects were university students in rehabilitation. Compared to general college students, rehabilitation students have a certain knowledge base related to injuries, which defines the specificity and research value of this subjects. This study provides guidance for reducing PARI in students in rehabilitation and may provide a basis for developing future injury prevention mechanisms for university students in general.

Avenues for Sport-Related Concussion Prevention in High School Football: Effect of Limiting Collision Practices

CONTEXT

Football continues to demonstrate the highest rate of sport-related concussion (SRC) in high school athletics. To mitigate the SRC risk, the Michigan High School Athletic Association (MHSAA) implemented rules aimed at reducing the number of collisions occurring in practices.

OBJECTIVE

To estimate the rates of SRC in MHSAA football programs and evaluate progressive limitations to collision practices over 5 consecutive seasons.

DESIGN

Retrospective cohort study.

SETTING

Michigan high school football.

PATIENTS OR OTHER PARTICIPANTS

High school (9th-12th grade) football athletes (>99% male) participating in MHSAA-sanctioned events.

MAIN OUTCOME MEASURE(S)

Designated administrators at each school recorded the total number of participating athletes and SRCs (defined as head injuries resulting from athletic participation that required the student-athletes to be withheld from activity after exhibiting signs, symptoms, or behaviors consistent with an SRC) in the MHSAA injury-surveillance system each season (2015-2016 through 2019-2020). Progressive limitations to collision practices occurred across the study period. We estimated athlete-exposures (AEs) as the total number of players multiplied by the total number of possible practices (11 weeks, 4 days each) or competitions (9 weeks, 1 day each) during each season. Incidence rates and rate ratios (RRs) with 95% CIs were used to compare practice and competition SRCs and each season with the most recent season.

RESULTS

A total of 7755 football SRCs were diagnosed across the 5-year period. The overall SRC rate was 8.03 per 10 000 AEs (95% CI = 7.85, 8.21). The competition SRC rate (30.13/10 000 AEs) was higher than the practice rate (3.51/10 000 AEs; RR = 8.58; 95% CI = 8.19, 9.00). The practice SRC rate was lower in 2017-2018 (RR = 0.86; 95% CI = 0.77, 0.97), 2018-2019 (RR = 0.89; 95% CI = 0.79, 1.0), and 2019-2020 (RR = 0.83; 95% CI = 0.74, 0.94) relative to 2015-2016.

CONCLUSIONS

We found that the progressive limitations to collision practices were protective against SRCs, as the rate of SRC was lower in the 3 most recent seasons relative to 2015-2016.

The Role of Reported Affective Symptoms and Anxiety in Recovery Trajectories After Sport-Related Concussion

BACKGROUND

There is growing awareness and clinical interest in athletes with affective symptoms after sport-related concussion (SRC), as these symptoms may contribute to overall symptoms and represent a modifiable risk factor of longer recovery. However, evidence of their effects on the entire return-to-play (RTP) trajectory, particularly among women and men, is limited.

PURPOSE/HYPOTHESIS

To examine the relationship between affective symptom reporting and RTP progression after SRC among a cohort of Division 1 student-athletes. We hypothesized that those endorsing affective symptoms, specifically nervous-anxious symptoms, spend more time in RTP progression and recovery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Using SRC data from the Ivy League-Big Ten Epidemiology of Concussion Study among varsity athletes through February 2020, we identified the 4 affective symptoms from the Sport Concussion Assessment Tool symptom inventory. We modeled the relationship between a 4-category affective symptom variable and time to symptom resolution, RTP, and RTP progression, adjusting for nonaffective symptom prevalence and concussion history. Cox regressions were used to estimate hazard ratios for time to event outcomes, and linear regressions were used to evaluate mean differences for continuous outcomes.

RESULTS

Among 2077 student-athletes (men, 63.5%) with SRC symptoms, affective symptom prevalence was 47.6% and 44.3% in women and men, respectively, and nervous-anxious prevalence was 24.2% and 22.5%, respectively. When comparing women with and without co-occurring affective symptoms, rates of symptom resolution and RTP were significantly lower in those with affective symptoms, and women with nervous-anxious symptoms spent significantly longer in RTP progression. When comparing men with and without co-occurring affective symptoms, rates of symptom resolution and RTP were significantly lower in those with co-occurring affective symptoms, and affective symptoms were not associated with time in RTP progression.

CONCLUSION

Student-athletes with affective symptoms and nervous-anxious symptoms exhibited delayed clinical recovery and RTP timelines, particularly for time in RTP. Symptom prevalence and concussion history contributed to this; however, unmeasured confounding remains, as indicated by the poor model fit. This study motivates future work to explore affective symptoms and RTP timelines, considering anxiety and risk/protective factors over time.

Canadians Reporting Sport-Related Concussions: Increasing and Now Stabilizing

BACKGROUND

Canada is currently engaged in a national harmonization of strategies to prevent and manage sport-related concussions.

OBJECTIVE

To examine the annual incidence rates of reported sport-related concussions or other brain injuries by participants in the Canadian Community Health Survey, a national public health survey which provides nearly 2 decades of serial data using consistent methodology.

DESIGN

Serial cross-sectional survey.

SETTING

Population-based Canadian survey from 2000 to 2018 that collects data on "concussions or other brain injuries."

PARTICIPANTS

Respondents 12 years and older.

INDEPENDENT VARIABLES

Sex and age categorized 12 to 14 years, 15 to 19 years, 20 to 29 years, and 30+ years.

OUTCOME MEASURES

National incidence rates of participants reporting concussions or other brain injuries occurring within the previous year while engaged in "organized sports/leisure sports or physical exercise."

RESULTS

Data were available for 2000/01, 2003, 2005/6, 2009/10, 2013/4, and 2017/8 (N = 757 383). A previously stable annual incidence of reported sport-related concussions or other brain injuries increased nearly 2 and a half-fold from 2005/06 through 2013/14 (P < 0.0001) but seems to have stabilized recently (2013/14 vs 2017/8, P = 0.35). This trend is similar for both men and women but is manifest primarily within youth (12-19 years) as opposed to adults (>19 years). Approximately 1 in 450 Canadians 12 years and older report sport-related concussions or other brain injuries as their most significant injury associated with disability in the previous year (2017-2018: 221 per 100 000 population, 95% confidence interval: 179-264).

CONCLUSIONS

In Canada, the annual incidence rates of reported sport-related concussions or other brain injuries is changing and may reflect improved reporting and recognition.

Characteristics of concussion based on patient age and sex: a multicenter prospective observational study

OBJECTIVE

Children with concussion frequently present to emergency departments (EDs). There is limited understanding of the differences in signs, symptoms, and epidemiology of concussion based on patient age. Here, the authors set out to assess the association between age and acute concussion presentations.

METHODS

The authors conducted a multicenter prospective observational study of head injuries at 10 EDs in Australia and New Zealand. They identified children aged 5 to < 18 years, presenting with a Glasgow Coma Scale score of 13-15, presenting < 24 hours postinjury, with no abnormalities on CT if performed, and one or more signs or symptoms of concussion. They extracted demographic, injury-related, and signs and symptoms information and stratified it by age group (5-8, 9-12, 13 to < 18 years).

RESULTS

Of 8857 children aged 5 to < 18 years, 4709 patients met the defined concussion criteria (5-8 years, n = 1546; 9-12 years, n = 1617; 13 to < 18 years, n = 1546). The mean age of the cohort was 10.9 years, and approximately 70% of the patients were male. Sport-related concussion accounted for 43.7% of concussions overall, increasing from 19.1% to 48.9% to 63.0% in the 5-8, 9-12, and 13 to < 18 years age groups. The most common acute symptoms postinjury were headache (64.6%), disorientation (36.2%), amnesia (30.0%), and vomiting (27.2%). Vomiting decreased with increasing age and was observed in 41.7% of the 5-8 years group, 24.7% of the 9-12 years group, and 15.4% of the 13 to < 18 years group, whereas reported loss of consciousness (LOC) increased with increasing age, occurring in 9.6% in the 5-8 years group, 21.0% in the 9-12 years group, 36.7% in the 13 to < 18 years group, and 22.4% in the entire study cohort. Headache, amnesia, and disorientation followed the latter trajectory. Symptom profiles were broadly similar between males and females.

CONCLUSIONS

Concussions presenting to EDs were more sports-related as age increased. Signs and symptoms differed markedly across age groups, with vomiting decreasing and headache, LOC, amnesia, and disorientation increasing with increasing age.

Removal From Activity After Sports- Related Concussion in Sex-Comparable Sports From the Michigan High School Athletic Association

BACKGROUND

Research has demonstrated that female athletes are more likely to report their sports-related concussion (SRC) symptoms compared with male athletes; however, it is unknown if these reporting behaviors correspond to immediate removal from activity in sex-comparable sports.

PURPOSE

To compare the incidence of high school student-athletes removed and not removed from activity after SRC in sex-comparable sports in Michigan.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

Participants included student-athletes diagnosed with SRC participating in Michigan High School Athletic Association-sponsored athletic activities (22 sex-comparable sports) between 2016 and 2019. All SRCs were recorded in the association's Head Injury Reporting System (HIRS) by certified athletic trainers, administrators, or coaches. Removal from activity indicated that the student-athlete was removed from play at the time of an injury event. If the student-athlete reported that his or her suspected injury event occurred earlier during activity or if symptom onset was delayed, "not removed from activity" was entered into the HIRS. Incidence proportions were calculated by dividing SRCs not removed by total SRCs in each sport. Risk ratios were calculated by dividing the incidence proportions of girls not removed by boys not removed in each sport.

RESULTS

A total of 4418 (2773 female, 1645 male) SRCs were reported, with the most occurring in female soccer players (n = 1023). Overall, 515 girls and 243 boys were not removed from activity, resulting in incidences of 0.19 (95% CI, 0.17-0.20) and 0.15 (95% CI, 0.13-0.17), respectively. Across all sports, girls were 1.26 (95% CI, 1.09-1.45) times as likely to not be removed from activity compared with boys. Of the sports with the most SRCs-soccer, basketball, baseball/softball, and lacrosse-girls had 1.37 (95% CI, 1.09-1.72), 1.15 (95% CI, 0.89-1.47), 1.19 (95% CI, 0.77-1.84), and 1.35 (95% CI, 0.94-1.95) times the risk of not being removed, respectively.

CONCLUSION

Girls were at greater risk of not being removed from activity compared with boys in sex-comparable sports. Results from this study should be incorporated into SRC education in Michigan and potentially elsewhere to inform affiliated personnel of potential sex differences and protect female student-athletes from further harm.

Sports-related concussions in high school females: an epidemiologic analysis of twenty-year national trends

The epidemiology of sports-related concussions (SRCs) and closed head injuries (CHIs) in high school females remains undefined at the national level, especially for unorganized sports and recreational activities. This study examines 1,176,092 national weighted estimates of SRCs or CHIs in female patients 14-18 years of age presenting to United States (US) emergency departments (EDs) between 2000 and 2019 in the National Electronic Injury Surveillance System (NEISS). The national weighted estimate of female patients in our study increased significantly (p < 0.001) between 2000 (9,835; 95% Confidence Interval [CI] 7,105-12,566) and 2019 (31,751; CI 26,392-37,110). The top five ranked sports and recreational activities most commonly associated with concussions and CHIs in female patients 14-18 years of age were: soccer (20.6%; CI 17.6%-23.6%); basketball (18.5%; CI 16.9%-20.1%); cheerleading (10.4%; CI 8.9%-11.9%); softball (10.1%; CI 9.0%-11.3%); volleyball (6.5%; CI 5.7%-7.2%). Simple univariate regression models showed that an increase of 10,000 annual female participants across all high school sports and recreational activities was associated with 308.7 (SE = 20.8, p < 0.001, R2 = 0.92) additional annual SRCs and CHIs presenting to US EDs. The promotion of concussion awareness and educational programs may help minimize SRCs and CHIs.

Sex-Based Differences in Symptoms with Mouthguard Use Following Pediatric Sport-Related Concussion

CONTEXT

Current evidence regarding the protective effect of mouthguard use on symptom severity in children and adolescents who sustain sport-related concussions is insufficient to make clinical recommendations.

OBJECTIVE

To compare the association between mouthguard-use and symptoms stratified by sex in the first 4-weeks after pediatric sport-related concussion. We hypothesized that mouthguard-use would be associated with lower symptoms.

DESIGN

Prospective cohort study.

SETTING

Nine Canadian pediatric emergency departments (EDs).

PATIENTS

Children aged 5-18 years presenting ≤48 hours of concussion sustained during a collision or contact sport.

MAIN OUTCOME MEASURES

Injury characteristics were collected using the Acute Concussion Evaluation. Primary outcome measure was symptom score (0-6), measured using age-appropriate versions (5-7 years; 8-12 years; 13-18 years) of the Post-Concussion Symptom Inventory. Independent variable was time postconcussion (at initial assessment, 1-, 2-, 4, weeks).

RESULTS

Of 1019 children (73% male; median [IQR] age=13.43[11.01,15.27] years), 42% wore a mouthguard at time of injury. There was no significant group by sex by time interaction for symptoms (χ23=0.27; p=.965). Male mouthguard users reported similar symptom scores in the ED (diff=-0.07; 95%CI:-0.23,0.09), at week-1 (diff=-0.02; 95%CI:-0.18,0.14), week-2 (diff=-0.03; 95%CI:-0.19,0.13), and week-4 (diff=-0.13; 95%CI:-0.29,0.04) compared with males who didn't wear a mouthguard. Female mouthguard users reported minimally higher symptom scores at week-1 compared with non-mouthguard users (diff=0.29; 95%CI:0.01,0.56). Symptom scores were not significantly different for females who wore a mouthguard and those who didn't in the ED (diff=0.22; 95%CI:-0.04,0.48), at week-2 (diff=0.22; 95%CI:-0.06,0.51), or week-4 (diff=0.08; 95%CI:-0.20,0.36).

CONCLUSION

Wearing a mouthguard at time of injury is not associated with reduced acute and subacute symptoms after sport-related concussion in either males or females who were treated in the ED compared with those who did not wear a mouthguard. Athletes are still encouraged to wear a mouthguard during sports since overwhelming evidence supports their use in preventing dental injuries.

Association of Sex With Adolescent Soccer Concussion Incidence and Characteristics

Importance

Because of the negative consequences of concussion, considerable research efforts have been directed toward understanding the risk factors for sport-related concussion (SRC) and its outcomes to better inform strategies for risk reduction. Girls are suggested to have an increased risk of concussion, warranting exploration into sex-dependent variations in concussion presentation and management, with the potential that this information might inform sex-specific rules directed toward risk reduction within sports.

Objective

To compare sex-associated differences in epidemiology and concussion management in adolescent soccer players within a prospective, longitudinal high school injury surveillance project.

Design, Setting, and Participants

This prospective, longitudinal cohort study assessed male and female soccer athletes from all high schools in the Michigan High School Athletic Association (MHSAA) during academic years 2016-2017 to 2018-2019.

Exposures

Sport-related concussion captured in the MHSAA Head Injury Reporting System.

Main Outcomes and Measures

Outcomes included details regarding each documented SRC event, including injury mechanism, immediate management, and return-to-play time. Multiple comparisons were made between male and female athletes regarding SRC risk, mechanism, short-term management, and outcomes.

Results

A total of 43 741 male and 39 637 female soccer athletes participated in MHSAA soccer during the 3 consecutive academic years of study (2016-2017: n = 751 schools; 2017-2018: n = 750 schools; and 2018-2019: n = 747 schools). During the 3 years of surveillance, 1507 of the 83 378 soccer athletes (1.8%) were reported to have SRC during soccer participation, including 557 boys (37.0%) and 950 girls (63.0%). Documented SRC risk in female soccer participants was greater than in male soccer participants (risk ratio, 1.88; 95% CI, 1.69-2.09; P < .001). Male soccer athletes most often sustained SRC from contact with another player (48.4%), whereas SRCs in female soccer players recorded in the Head Injury Reporting System were most often from nonplayer contact events (41.9%; P < .001). Adolescent male soccer players with a documented SRC were more likely to be removed from play on the day of injury (odds ratio, 1.54; 95% CI, 1.15-2.06; P = .004). Although the overall median time to return to play was 11 days (interquartile range [IQR], 7-15 days), male athletes typically returned 2 days earlier than female athletes (median, 10 [IQR, 7-14] days vs 12 [IQR, 7-16] days; Peto test P < .001).

Conclusions and Relevance

In this cohort study, sex-associated differences were revealed among adolescent soccer athletes in SRC risk, mechanism of injury, immediate management, and outcomes in injuries documented in a statewide injury reporting system. Thus, consideration might be given to sex-specific approaches to participation and concussion management in the sport.

Data-Driven Risk Classification of Concussion Rates: A Systematic Review and Meta-Analysis

BACKGROUND

Concussion is a growing public health concern and generating concussion prevention programs depends on identifying high-risk sports and characteristics. Identifying the roles of sport, sex, and participation level (e.g., high school versus collegiate athletics) in concussion risk would facilitate more informed decision-making regarding sports participation and generate better targeted prevention strategies.

OBJECTIVES

The current study's objectives were to: (1) determine the magnitude and hierarchy of sports-related concussion (SRC) risk across an array of events and (2) evaluate the modifying roles of sex, participation level, and session type on SRC rates.

METHODS

A literature search was conducted on PubMed, searching concussion studies published between 2001 and December 2019. Inclusion criteria for studies required: (1) concussion occurred during sport, (2) that the SRC was clinically diagnosed, and (3) athlete exposures and concussions could be extracted or estimated. A study was excluded if it: (1) was not an original research article, (2) was not written in English language, (3) was an animal study, (4) did not have enough data to calculate SRC rates, (5) included professional or youth sample, and/or (6) contained data collected prior to 2001. The meta-analysis and meta-regression analyses were fit using a random effects model.

RESULTS

Search results returned 2695 unique research articles, with 83 studies included in analyses. Sport, sex, participation level, and session type all significantly influenced SRC rates. Overall, rugby had the highest concussion rate and was classified as the highest risk sport (28.25 concussions per 10,000 athlete exposures). Overall, females had a higher concussion rate than males. Only lacrosse demonstrated a higher concussion rate for males compared to females. Collegiate athletes had higher concussion rates than high school athletes. Games were associated with 2.01 more concussions per 10,000 AEs than practices.

CONCLUSIONS

This meta-analysis demonstrated rugby has the highest concussion risk, followed by American Football, ice hockey, and wrestling. Concussion risk was influenced by sport, sex, participation, and session. Identifying the factors and environments that influence concussion risk can facilitate risk reduction and prevention strategies.

Clinical Recovery Timelines following Sport-Related Concussion in Men's and Women's Collegiate Sports

CONTEXT

Past work has identified sex differences in sport-related concussion (SRC) incidence and recovery time; however, few have examined sex differences in specific recovery trajectories: time to symptom resolution, return-to-academics, and return-to-athletic activity across collegiate sports.

OBJECTIVE

To examine sex differences in SRC recovery trajectories across a number of varsity sports with differing levels of contact.

DESIGN

Descriptive Epidemiology Study.

SETTING

College varsity and club sports.

PATIENTS OR OTHER PARTICIPANTS

SRCs sustained by student-athletes (N=1,974; 38.7% female) participating in Ivy League sports were tracked from 2013/14-2018/19.

INTERVENTION(S)

Athletic trainers collected concussive injury and recovery characteristics as part of the Ivy League-Big Ten Epidemiology of Concussion Study's surveillance system.

MAIN OUTCOME MEASURE(S)

Time to symptom resolution, return-to-academics, and return-to-limited and full athletic activity were collected. Survival analyses determined time from injury to each recovery outcome for males and females by sport. Peto tests compared recovery outcomes between males and female athletes and by sport.

RESULTS

The median time to symptom resolution overall was 9 days [IQR:4,18], return-to-academics was 8 days [IQR:3,15], return-to-limited activity was 12 days [IQR:8,23], and return-to-full activity was 16 days [IQR:10,29]. There were significant differences overall between sexes for median time to symptom resolution (males: 8 days [IQR:4,17], females: 9 days [IQR:5,20], p=0.029) and return-to-academics (males: 7 days [IQR:3,14], females: 9 days [IQR:4,17], p<.001), but not return to athletics (limited activity, p=0.107; full activity, p=0.578). Within-sport comparisons found that female lacrosse athletes had longer symptom resolution (p=0.030) and return to academics (p=0.035) compared to males, while male volleyball athletes took longer to return to limited (p=0.020) and full (p=0.049) athletic activity compared to females.

CONCLUSION

There were significant differences in recovery timelines between sexes. Females experienced longer symptom duration and time to return-to-academics compared to male athletes, but females and males presented similar timelines for return-to-athletics.

Positive association between serum quinolinic acid and functional connectivity following concussion

The molecular mechanisms underlying the diverse psychiatric and neuropathological sequalae documented in subsets of athletes with concussion have not been identified. We have previously reported elevated quinolinic acid (QuinA), a neurotoxic kynurenine pathway metabolite, acutely following concussion in football players with prior concussion. Similarly, work from our group and others has shown that increased functional connectivity strength, assessed using resting state fMRI, occurs following concussion and is associated with worse concussion-related symptoms and outcome. Moreover, other work has shown that repetitive concussion may have cumulative effects on functional connectivity and is a risk factor for adverse outcomes. Understanding the molecular mechanisms underlying these cumulative effects may ultimately be important for therapeutic interventions or the development of prognostic biomarkers. Thus, in this work, we tested the hypothesis that the relationship between QuinA in serum and functional connectivity following concussion would depend on the presence of a prior concussion. Concussed football players with prior concussion (N = 21) and without prior concussion (N = 16) completed a MRI session and provided a blood sample at approximately 1 days, 8 days, 15 days, and 45 days post-injury. Matched, uninjured football players with (N = 18) and without prior concussion (N = 24) completed similar visits. The association between QuinA and global connectivity strength differed based on group (F(3, 127) = 3.46, p = 0.019); post-hoc analyses showed a positive association between QuinA and connectivity strength in concussed athletes with prior concussion (B = 16.05, SE = 5.06, p = 0.002, 95%CI[6.06, 26.03]), but no relationship in concussed athletes without prior concussion or controls. Region-specific analyses showed that this association was strongest in bilateral orbitofrontal cortices, insulae, and basal ganglia. Finally, exploratory analyses found elevated global connectivity strength in concussed athletes with prior concussion who reported depressive symptoms at the 1-day visit compared to those who did not report depressive symptoms (t(15) = 2.37, mean difference = 13.50, SE = 5.69, p = 0.032, 95%CI[1.36, 25.63], Cohen's d = 1.15.). The results highlight a potential role of kynurenine pathway (KP) metabolites in altered functional connectivity following concussion and raise the possibility that repeated concussion has a "priming" effect on KP metabolism.

Time to Authorized Clearance from Sport-Related Concussion: The Influence of Healthcare Provider and Medical Facility

CONTEXT

Return-to-play following sport-related concussion(SRC) requires authorized clearance from a healthcare provider(HCP). Variability in HCPs and facilities where athletes seek care may influence return time.

OBJECTIVE

Determine the initial examiner, HCPs that authorize clearance, and medical facilities authorizing clearance among high school student-athletes following SRC, and compare authorized clearance time by HCPs and medical facilities.

DESIGN

Prospective Cohort Study.

SETTING

High school.

PATIENTS OR OTHER PARTICIPANTS

Student-athletes(n=16,001) with SRC participating in STATE-XXX High School Athletic Association(XHSAA)-sponsored athletics.

MAIN OUTCOME MEASURE(S)

Frequencies of initial examiner and authorized clearance for each HCP(Doctor of Osteopathic Medicine(DO), Doctor of Medicine(MD), Nurse Practitioner(NP), Physician Assistant(PA)) and medical facility (Neurologist's Office, Team Physician, Primary Care Physician or Pediatrician's Office(PCP), Hospital, Urgent/Ready Care) for each SRC case. Kaplan-Meier curves and Peto tests evaluated differences in median time to authorized clearance between HCPs and facilities. Only cases with a follow-up authorized clearance date(80.3%, n=12,856) were included in authorized clearance and time to return analyses.

RESULTS

An athletic trainer was at least one of the initial examiners for 71.3%(n=11,404) of cases; 80.2%(n=12,990) had only one initial examiner. There was an association between initial examiner and medical facility providing clearance for athletic director(χ2=52.6, p≤.001, V=.06), athletic trainer(χ2=172.0, p≤.001, V=.12), coach(χ2=161.5, p≤.001, V=.11), DO(χ2=59.4, p≤.001, V= 07), and NP(χ2=10.0, p .03, V=.12). The majority(n=8,218, 63.9%) received clearance by an MD; 70.8%(n=9,099) were cleared at a PCP. Median time to authorized clearance varied by facility(Urgent/Ready Care: 7 days[4,11], Hospital: 9 days[6,14], PCP: 10 days[6,14], Team Physician: 12 days[8,16], Neurologist Office: 13 days[9,20]; p ≤ .001).

CONCLUSIONS

Clearance was frequently provided by an MD and at a PCP. Median time to return to unrestricted participation following SRC varied by HCP and medical facility. Future research should elucidate why differences exist and determine why athletes seek care at different medical facilities.

A Promising Subject-Level Classification Model for Acute Concussion Based on Cerebrovascular Reactivity Metrics

Concussion imaging research has primarily focused on neuronal disruption with lesser emphasis directed toward vascular dysfunction. However, blood flow metrics may be more sensitive than measures of neuronal integrity. Vascular dysfunction can be assessed by measuring cerebrovascular reactivity (CVR)-the change in cerebral blood flow per unit change in vasodilatory stimulus. CVR metrics, including speed and magnitude of flow responses to a standardized well-controlled vasoactive stimulus, are potentially useful for assessing individual subjects following concussion given that blood flow dysregulation is known to occur with traumatic brain injury. We assessed changes in CVR metrics to a standardized vasodilatory stimulus during the acute phase of concussion. Using a case control design, 20 concussed participants and 20 healthy controls (HCs) underwent CVR assessment measuring blood oxygen-level dependent (BOLD) magnetic resonance imaging using precise changes in end-tidal partial pressure of CO₂ (PETCO₂). Metrics were calculated for the whole brain, gray matter (GM), and white matter (WM) using sex-stratification. A leave-one-out receiver operating characteristic (ROC) analysis classified concussed from HCs based on CVR metrics. CVR magnitude was greater and speed of response faster in concussed participants relative to HCs, with WM showing higher classification accuracy compared with GM. ROC analysis for WM-CVR metrics revealed an area under the curve of 0.94 in males and 0.90 in females for speed and magnitude of response respectively. These greater than normal responses to a vasodilatory stimulus warrant further investigation to compare the predictive ability of CVR metrics against structural injury metrics for diagnosis and prognosis in acute concussion.

What is the risk of recurrent concussion in children and adolescents aged 5-18 years? A systematic review and meta-analysis

OBJECTIVE

We aimed to examine the risk of concussion in children with a previous history of concussion.

DESIGN

Systematic review and meta-analysis. The primary outcome was number of children with and without a previous lifetime history of concussion who sustained a diagnosed concussion within each study period. Risk of bias was assessed using the Newcastle-Ottawa Scale. A random effects model was used to estimate a pooled risk ratio (RR) with corresponding 95% CIs; results were summarised in forest plots.

DATA SOURCES

Four electronic databases (MEDLINE, Embase, CINAHL, SPORTDiscus) and selected reference lists were searched (PROSPERO registration No CRD42019135462).

ELIGIBILITY CRITERIA

Original English language peer-reviewed publications that compared concussion risk in children aged 5-18 years with and without a previous concussion history in which risk estimates were reported or able to be calculated.

RESULTS

Of 732 identified studies, 7 studies representing 23 411 children (risk of bias range, 7-9; maximum possible score=9) were included for meta-analysis. Pooled risk of sustaining a concussion was more than three times greater in children with a previous concussion compared with those with no previous concussion (RR=3.64; 95% CI: 2.68 to 4.96; p<0.0001; I ²=90.55%). Unreported sex-stratified data precluded direct comparison of concussion risk in male versus female athletes.

CONCLUSION

Previously concussed children have four times the risk of sustaining a concussion compared with those with no previous concussion history. This should be a consideration for clinicians in return to sport decision-making. Future studies examining subsequent recurrent concussion in youth sports must consider sex differences.

Concussion Knowledge, Attitudes, and Self-Reporting Intentions in Youth Athletes

CONTEXT

Although it has been suggested that developmental and sociological factors play a role in concussion reporting, the empirical evidence related to this is limited.

OBJECTIVE

To examine the influences of sex, school level, school location, concussion-reporting history, and socioeconomic status on concussion-related knowledge, attitudes, and reporting intentions among middle school and high school athletes.

DESIGN

Cross-sectional study.

SETTING

Master students and High School athletes attending pre-participation examinations (PPEs) were asked to complete paper-based surveys.

PATIENTS OR OTHER PARTICIPANTS

Overall, 541 athletes representing 18 sports returned fully completed surveys.

MAIN OUTCOME MEASURE(S)

Outcomes were concussion-related knowledge, perceived seriousness, positive feelings about reporting, and self-reporting intentions. We examined group differences in these outcomes across levels of the explanatory variables of sex, school level (middle school versus high school), school location (urban versus rural), concussion self-reporting history (yes or no), and socioeconomic status (free or reduced-price lunch versus no free or reduced-price lunch) using Wilcoxon rank sum tests. Then we used multivariable ordinal logistic regression models to identify predictors of higher score levels for each outcome. Odds ratio (OR) estimates with 95% confidence intervals (CIs) excluding 1.00 were deemed significant.

RESULTS

Odds of higher levels of knowledge were higher in urban versus rural school student-athletes (ORAdjusted = 1.81; 95% CI = 1.03, 3.17), and lower in student-athletes on free or reduced-price lunch versus those not on free or reduced-price lunch (ORAdjusted = 0.52; 95% CI = 0.36, 0.77). Similarly, odds of higher levels of seriousness were lower in male versus female student-athletes (ORAdjusted = 0.48; 95% CI = 0.32, 0.72). Further, odds of higher levels of self-reporting intentions were lower among male versus female student-athletes (ORAdjusted = 0.53; 95% CI = 0.37, 0.75).

CONCLUSIONS

Developmental and sociological factors were differentially associated with concussion-related knowledge, attitudes, and self-reporting intentions. These results can inform medical providers, parents, and coaches with regard to context-specific clinical assessments of concussion symptoms.

Concussion Epidemiology in Youth Sports: Sports Study of a Statewide High School Sports Program

BACKGROUND

Current research on concussion incidence in youth athletes (age <18 years) is small and limited by variability in injury reporting and diagnostic methodology.

HYPOTHESIS

Concussion injuries commonly occur in high school sports programs. The likelihood of concussion among student-athletes (aged 13-18 years) depends on the sport they are participating in as well as the sex of the athlete.

STUDY DESIGN

Descriptive epidemiology study.

LEVEL OF EVIDENCE

Level 4.

METHODS

A retrospective analysis of all Hawaii high school athletes aged 13 to 18 years participating in 14 sports from 2011 through 2017 was performed as part of a statewide standardized concussion assessment and management program.

RESULTS

A total of 5993 concussions were identified among 92,966 athletes. The overall concussion rate was 0.96 (95% CI, 0.94-0.99). Girls' judo had the highest concussion rate (1.92; 95% CI, 1.68-2.17) followed by football (1.60; 95% CI, 1.53-1.66). The concussion rate for boys (1.0; 95% CI, 0.97-1.03) was higher than that for girls (0.91; 95% CI, 0.87-0.95); however, in 4 of the 5 sports in which both girls and boys participated, girls had a higher rate of concussion injury.

CONCLUSION

The likelihood of concussion among student-athletes aged 13 to 18 years may be higher than previously thought and varies depending on sport and sex.

CLINICAL RELEVANCE

Epidemiologic data on concussion injury in children and adolescents are useful in accurately determining the relative risks of high school sports participation and may be valuable in determining the appropriate allocation of health care and scholastic resources for student-athletes, as well as the impact of rule and training modifications designed to improve participant safety.

Women Are at Higher Risk for Concussions Due to Ball or Equipment Contact in Soccer and Lacrosse

BACKGROUND

There is ample evidence to suggest sex- and gender-based differences in the incidence of sports-related concussions. The mechanisms of concussion may vary between male and female athletes and contribute to this observed difference. Understanding the underlying etiology by pooling data from primary studies across different settings and sport types will inform interventions that can reduce concussion rates.

QUESTIONS/PURPOSES

Specifically, we asked: (1) In which sports are female athletes less likely to experience concussions from player contact? (2) In which sports are female athletes more likely to experience concussions because of ball or equipment contact?

METHODS

PubMed, EMBASE, and Cochrane Library databases were searched to identify articles published from January 2000 to December 2018. Ten studies met the inclusion criteria, which were studies that reported concussion incidence by mechanism for both male and female athletes. Exclusion criteria included non-English studies, conference abstracts, and studies on non-sports related concussions. The sports represented by the 10 studies included ice hockey (n = 4), soccer (n = 5), basketball (n = 4), baseball/softball (n = 4), and lacrosse (n = 5). The rate ratio was calculated as the incidence rate in female athletes/male athletes for each concussion mechanism or activity. Data were pooled using the DerSimonian-Laird random-effects model. Study quality was assessed with the Newcastle-Ottawa Scale.

RESULTS

Female athletes were at lower risk of player-contact-induced concussions in lacrosse (pooled rate ratio 0.33 [95% CI 0.25 to 0.43]; p < 0.001), basketball (pooled rate ratio 0.86 [95% CI 0.76 to 0.97]; p = 0.01), ice hockey (pooled rate ratio 0.64 [95% CI 0.56 to 0.73]; p < 0.001), soccer (pooled rate ratio 0.70 [95% CI 0.66 to 0.75]; p < 0.001), and soccer heading (pooled rate ratio 0.80 [95% CI 0.72 to 0.90]; p < 0.001); in these sports, men were at higher risk of concussions from player contact. Female athletes were more likely to experience concussions because of ball or equipment contact in lacrosse (pooled rate ratio 3.24 [95% CI 2.10 to 4.99]; p < 0.001), soccer (pooled rate ratio 2.04 [95% CI 1.67 to 2.49]; p < 0.001), and soccer heading (pooled rate ratio 2.63 [95% CI 1.84 to 3.77]; p < 0.001).

CONCLUSIONS

The mechanism or activity underlying concussions differs between male and female athletes across different sports. This finding remains the same regardless of whether there are rule differences between the men's and women's games. The implementation of other interventions are required to further ensure player safety, including protective head equipment, concussion prevention training, or rules limiting player contact in the men's game.

LEVEL OF EVIDENCE

Level III, retrospective study.

Early cerebrovascular and long-term neurological modifications ensue following juvenile mild traumatic brain injury in male mice

Clinical evidence suggests that a mild traumatic brain injury occurring at a juvenile age (jmTBI) may be sufficient to elicit pathophysiological modifications. However, clinical reports are not adequately integrated with experimental studies examining brain changes occurring post-jmTBI. We monitored the cerebrovascular modifications and assessed the long-term behavioral and electrographic changes resulting from experimental jmTBI. In vivo photoacoustic imaging demonstrated a decrease of cerebrovascular oxygen saturation levels in the impacted area hours post-jmTBI. Three days post-jmTBI oxygenation returned to pre-jmTBI levels, stabilizing at 7 and 30 days after the injury. At the functional level, cortical arterioles displayed no NMDA vasodilation response, while vasoconstriction induced by thromboxane receptor agonist was enhanced at 1 day post-jmTBI. Arterioles showed abnormal NMDA vasodilation at 3 days post-jmTBI, returning to normality at 7 days post injury. Histology showed changes in vessel diameters from 1 to 30 days post-jmTBI. Neurological evaluation indicated signs of anxiety-like behavior up to 30 days post-jmTBI. EEG recordings performed at the cortical site of impact 30 days post-jmTBI did not indicate seizures activity, although it revealed a reduction of gamma waves as compared to age matched sham. Histology showed decrease of neuronal filament staining. In conclusion, experimental jmTBI triggers an early cerebrovascular hypo‑oxygenation in vivo and faulty vascular reactivity. The exact topographical coherence and the direct casualty between early cerebrovascular changes and the observed long-term neurological modifications remain to be investigated. A potential translational value for cerebro-vascular oxygen monitoring in jmTBI is discussed.

Physical-Activity-Related Injuries and Risk Factors among Secondary School Students in Hong Kong

Increase in physical activity (PA) might elevate risks for physical-activity-related injuries (PARIs). This study aimed to investigate the incidence rate and risk factors for PARIs among secondary school students in Hong Kong. All eligible students from three secondary schools were invited to participate in the study from November to December 2014. Information on PARI occurrences in the past 12 months, PA participation, and sociodemographics was collected. Multivariate and hierarchical logistic regression models were performed to estimate the risk of potential factors for PARIs. In total, 1916 students in forms 1-6 (aged 14.3 ± 1.7 years) completed valid questionnaires, with an overall yearly PARI incidence rate of 32.1% (boys: 34.3%; girls: 29.3%). There were sex differences in the risk factors identified, except that family size was associated with PARIs for all participants. Longer duration and higher intensity of PA increased the risk for PARI occurrences in both sexes. In conclusion, PARIs were prevalent among secondary school students in Hong Kong, and different sexes had different PARI incidence rates and were influenced by different risk factors. There is an urgent call for effective sex-specific interventions to prevent PARIs in this population.