Table 1 Prospective injury surveillance studies evaluating concussion by comparable sport and gender

Sport	Reference	Study method	Subjects/activity	Study length/no. of schools	Higher concussion rate	Statistical difference	Approximate no. of concussions compared
Football (soccer)	7	Case control	PRO	6 yr,	F (2.4×)	Not analysed	15
	7	Case control	G	20 tournaments	F (2.4×)	Not analysed	15
	6	Descriptive	HS,COL	1 yr,	F	yes	40
	6	Descriptive	PG	100 schools	F	yes	40
	8, 9	Descriptive	COL	15 yr,	F	yes	400
	8, 9	Descriptive	G	85 schools/yr	F	yes	400
	13	Cohort	HS	3 yr,	M	Not analysed	15
	13	Cohort	PG	100 schools/yr	M	Not analysed	15
Basketball	5	Descriptive	HS	2 yr,	F (2×)	Not analysed	unknown
	5	Descriptive	PG	100 schools/yr	F (2×)	Not analysed	unknown
	6	Descriptive	HS,COL	1 yr,	F	yes	35
	6	Descriptive	PG	100 schools	F	yes	35
	10, 11	Descriptive	COL	16 yr,	F	yes	200
	10, 11	Descriptive	G	120 schools/yr	F	yes	200
	13	Cohort	HS	3 yr,	F	Not analysed	10
	13	Cohort	PG	100 schools/yr	F	Not analysed	10
Ice hockey	14	Cohort	COL	1 yr,	F	no	15
	14	Cohort	PG	6 schools	F	no	15
	15, 16	Descriptive	COL	4 yr,	F	no	100
	15, 16	Descriptive	PG	20 schools/yr	F	no	100

HS, high school; COL, college; F, female; M, male; PRO, professional; G, game; PG, practice and game.