Is there a gender difference in concussion incidence and outcomes?

Objective: To determine if there is a gender difference in the incidence and outcomes of sport concussion. Design: Critical literature review of sport concussion by gender. Intervention: PubMed and major sports medicine journals were reviewed using the keywords concussion and gender. Articles included in this paper were English prospective surveillance that included concussion as an injury option conducted over the past 10 years, involved data collected by qualified medical personnel (athletic trainers/therapists or medical doctors) and used injury rates as opposed to raw counts. Only data from sports (soccer, basketball and ice hockey) where actions, equipment and most rules were similar between genders were reviewed. Results: For the PubMed search, using "concussion" and "gender" as keywords, there were 51 articles. Ten studies (four in football (soccer), four in basketball and two in ice hockey, including high school, college and professional athletes) were included in the incidence portion of the paper. Nine of the studies showed higher absolute injury rates for female concussion compared to their male counterparts with four of them reaching statistical significance. Five of the studies (two football (soccer), two basketball and one ice hockey) examined concussion mechanism and in all cases, males had a higher absolute percent of player contact concussions while females had a higher absolute percentage of surface or ball contact concussion episodes. Two brain injury and four sport concussion outcome papers were reviewed. Traumatic brain injury outcome was shown to be worse in females than in males for a majority of measured variables; females also are shown to have different baseline and post-concussion outcomes on neuropsychological testing. Conclusions: After evaluating multiple years of concussion data in comparable sports, the evidence indicates that female athletes may be at greater risk for concussion than their male counterparts. There also is some evidence that gender differences exist in outcomes of traumatic brain injury and concussions. Because concussion is a clinical diagnosis often depending on self reporting and with no established biological marker or consistent symptoms/definitions, and because there is evidence that females are more honest in reporting general injuries than males, it is unclear whether the concussion incidence data, while generally consistent in showing a higher risk in females as compared to males in similar sports, is a true difference or is influenced by a reporting bias.