Table 3

Study population, design characteristics, equipment item, and intervention and control arm data

Paper	Year	Sport	Randomised (Y/N)	Exposure data	Type of exposures	INT group	INT population size	INT concussions	INT crude concussion rate	Concussion incidence per 1000 exposures	CTRL group	CTRL population size	CTRL concussions	CTRL crude concussion rate	Concussion incidence per 1000 exposures	Incidence ratio (EXP/CTRL)
Barbic et al15	2005	American Football and Rugby	Y	N	NR	WIPSS Brain-Pad MG	308	22	0.07	NR	Standard MG	306	21	0.07	NR	NR
Benson et al16	1999	Hockey	N	Y	Practices/games	Full face shield	319	38	0.12	1.57	Half face shield	323	41	0.13	1.53	1.03
Collins et al17	2006	American Football	N	N	NR	Revolution helmet	1173	62	0.05	NR	Standard helmet	968	74	0.08	NR	NR
Hollis et al22	2009	Rugby	N	Y	Player game hours	Always wore HG	671	NR	NR	7.39	Never wore HG	985	NR	NR	7.48	0.99
Hollis et al22	2009	Rugby	N	Y	Player game hours	Always wore MG	1735	NR	NR	7.45	Never wore MG	236	NR	NR	8.62	0.86
Kemp et al23	2008	Rugby	N	Y	Player game hours	MG	NR	75	NR	4	No MG	NR	17	NR	5.8	0.69
Kemp et al23	2008	Rugby	N	Y	Player game hours	HG	NR	7	NR	2	No HG	NR	85	NR	4.6	0.43
Kerr et al18	2015	American Football	N	Y	Practices/games	HUF+PW	2108	23	0.02	NR	No HUF	704	22	0.03	NR	NR
Labella et al26	2002	Basketball	N	Y	Practices/games	MG	NR	3	NR	0.35	No MG	NR	34	NR	0.55	0.64
Marshall et al24	2005	Rugby	N	Y	Practices/games	MG	*NR	*NR	NR	NR	No MG	*NR	*NR	NR	NR	NR
Marshall et al24	2005	Rugby	N	Y	Practices/games	HG	*NR	*NR	NR	NR	No HG	*NR	*NR	NR	NR	NR
McGuine et al19	2014	American Football	N	Y	Practices/games	Custom or specialised MG	901	99	0.11	NR	Standard MG	1386	107	0.08	NR	NR
McIntosh and McCrory25	2001	Rugby	Y	Y	Games	HG	NR	7	NR	5.94	No HG	NR	2	NR	5.6	1.06
McIntosh20	2009	Rugby	Y	Y	Player game hours	Modified HG	1474	80	0.05	7.5	No HG	1493	67	0.04	6.7	1.12
McIntosh20	2009	Rugby	Y	Y	Player game hours	Standard HG	1128	52	0.05	6.4	No HG	1493	67	0.04	6.7	0.96
Stuart et al28	2002	Hockey	N	Y	Player game hours	Half face shield	NR	5	NR	8.2	No face shield	NR	4	NR	12.2	0.67
Stuart et al28	2002	Hockey	N	Y	Player game hours	Full face shield	NR	2	NR	2.9	No face shield	NR	4	NR	12.2	0.24
Thompson et al14	1996	Bicycling	N	N	NR	Helmet	1718	62	0.04	NR	No helmet	1672	141	0.08	NR	NR
Winters and DeMont21	2014	American Football	Y	N	NR	Custom MG	220	8	0.04	NR	Standard MG	192	16	0.08	NR	NR
Wisniewski et al27	2004	American Football	N	Y	Practices/games	Custom MG	NR	169	NR	0.99	Standard MG	NR	200	NR	1.10	0.9

*Total population size=304; concussions=22.
CTRL, control; HG, headgear; HUF, Heads Up Football; PW, Pop Warner; INT, interventional; MG, mouthguard; N, no; NR, not reported; Y, yes.