Table 2

Investigation of male youth ice hockey incidence and calculated estimates from the literature

Study	Period	Type	Country	Age (years)	No. of players	No of concussions	Exposure (PGH)	Incidence (/1000 PGH)
The first four rows of the table are from the present study. Results are calculated from: *mean number of game hours per player × number of players; †number of injuries × proportion of injuries that were concussions; ‡number of injuries ÷ incidence of injury per player game hour. ‡Median; all other numerical values in this column are range. Retro, retrospective; P, prospective; NR, not reported.
Official reports	2003–2004	Retro	Canada	12 to 17	19548	60	17 1045	0.35
Volunteer reports	2002–2003	Pro	Canada	12 to 17	792	22	3861	5.70
Elite	2001–2003	Retro	Canada	15 to 17	475	79	10 688	7.39
Non-elite	2004	Retro	Canada	11 to 17	107	26	1605	16.20
Gerberich¹³	1982–1983	Retro	USA	16.1‡	251	22	4141.5*	4.35
Roberts¹⁹	1993–1994	Pro	USA	12 to 13	132	2	86.4	23.15
				14 to 15	127	1	93.6	10.68
				12 to 15	163	2	108	18.52
Roberts¹⁸	1994	Pro	USA	<20	273	4	213.9	18.70
Smith²¹	1994–1995	Pro	USA	NR	86	1†	639‡	1.56
Stuart²²	1993–1994	Pro	USA	16 to 21	66	0	4707	0