Epidemiology of Head Injuries Focusing on Concussions in Team Contact Sports: A Systematic Review.

Background: Although injuries to the head represent a small proportion of all sport injuries, they are of great concern due to their potential long-term consequences, which are even suspected in mild traumatic brain injuries.

Objective: The aim of this review was to compare the incidence of concussions and other head injuries in elite level football, rugby, ice hockey and American Football.

Methods: Four electronic databases (CINAHL, PsycINFO, Web of Science, PubMed) were searched. Prospective cohort studies on the incidence of concussion in elite athletes aged 17 years or older that were published in an English-language peer-reviewed journal since 2000 were included. Two authors independently evaluated study eligibility and quality. The extracted data on concussions were pooled in a meta-analysis using an inverse-variance fixed-effects model. The extracted data on head injuries were reported in a narrative and tabular summary.

Results: The search yielded 7673 results of which 70 articles were included in the qualitative and 47 in the quantitative analysis. In our meta-analysis, we found the highest concussion incidences in rugby match play (3.89 and 3.00 concussions per 1000 h and athletic exposures (AEs), respectively), and the lowest in men's football training (0.01 and 0.08 per 1000 h and AEs, respectively). Overall, concussions and all head injuries were rare in training when compared to match play. Female players had an increased concussion risk in football and ice hockey when compared to male players.

Conclusion: Future research should focus on concussion in women's contact sports, as there is little evidence available in this area. Methodological deficits are frequent in the current literature, especially regarding sample size and study power, and should be avoided.