Incidence of concussion in contact sports: a systematic review of the evidence

Primary objective: To estimate incidence of concussion in contact sports. Research design: Systematic review of the literature on concussion in contact sports. Methods and procedures: MEDLINE was searched from 1985 - 2000. Older articles cited in retrieved articles were also reviewed. Articles meeting the inclusion/exclusion criteria were critically appraised for methodologic quality. The incidence of concussion was recalculated in some cases. Results: Twenty-three out of 63 identified articles were accepted to estimate the risk of concussion. Overall, ice hockey and rugby have the highest incidence of concussion and soccer has the lowest. Male boxers and female taekwondo participants have the highest frequency of concussion at the recreational level. Conclusions: There are few good studies on the incidence of concussion and limited information on the risk of concussion for females in contact sports. Some common methodological problems were also identified in this literature with the hope of improving future studies.