Table 2.

Summary of studies comparing full-face and open helmets on head and cervical outcomes in motorcyclists who had road accidents.

Factors/Study	Hitosugi et al	Cini et al	Lopes Albuquerque et al	Yu et al
Country	Japan	Brazil	Brazil	Taiwan
Year	2004	2014	2014	2011
Study design	Retrospecitve study	Case-control	Retrespective cohort	Matched case-control
Inclusion	Jikei University autopsies of motorcyclists who died in traffic accidents from 1998 to 2002	Patients with facial injuries from a motorcycle accident	Motorcycle accident victims who had to be referred to the outpatient clinic at the hospital	As in Table 1
Exclusion	NA	Those with injuries to any other part of the body or whose injuries resulted in death	Incomplete hospital records or refusal to participate	As in Table 1
Numbers of participants	36	1,628	253	458 pairs
Primary outcome(s)	Number of severely injured body regions	Facial injuries	Facial Injury Severity Scale, traumatic brain injury, facial fractures	Head injury
Full-face helmet with head or cervical injury, n	9*	12**	24***	50
Full-face helmet without head or cervical injury, n	8*	63**	22***	73
Open helmet with head or cervical injury, n	16*	9**	39***	106
Open helmet without head or cervical injury, n	3*	25**	12***	149

Note. NA: not available; * indicates severe head injury; ** indicates zygomatic fracture; ***indicates traumatic brain injury.