Characteristics of included studies
| Study | Sport | Study design | Duration (seasons) and location | Eligibility/study population | Exposure measures | Outcome measures | Main results |
|---|---|---|---|---|---|---|---|
| Macnab et al2 | Ski and snowboard | Case–control | November 1998 to May 1999 (one season) at a major ski resort in British Columbia, Canada | All young skiers and snowboarders (less than 13 years of age) presenting with head, face, or neck injuries to the one central medical facility at the base of the mountain | Helmet use | Head, neck, face injuries: treatment by physicians (n=70) | Head and neck injury: Among those without helmets, relative risk of head/neck/face injury was 2.24 (95% CI 1.23 to 4.12) compared with those who wore helmets |
| Cervical spine injuries: treatment by physicians (n=22) | Cervical spine injuries: Of the children who sustained a cervical spine injury, 32% were wearing a helmet at the time of the incident (RR 2.0, 95% CI 0.80 to 5.6; p=0.15 for cervical spine injury when not wearing a helmet). None of the cervical spine injuries were considered major. | ||||||
| Hagel et al15 | Ski and snowboard | Matched case–control and case crossover study | November 2001 to April 2002 (one season) at 19 ski resorts in Quebec, Canada | Cases=1082 skiers and snowboarders | Helmet use | Head injuries: treatment by ski patrollers (n=693) | Head injury: The adjusted OR for helmet use was 0.71 (95% CI 0.55 to 0.92), and for those with more severe head injuries requiring evacuation by ambulance it was 0.44 (0.95% CI 0.24 to 0.81). |
| Controls=3295 skiers and snowboarders | Neck injuries: treatment by ski patrollers (n=131) | Neck injury: The adjusted OR for helmet use for participants with any neck injury was 0.62 (0.33 to 1.19) and for participants who required evacuation by ambulance for neck injuries it was 1.29 (0.41 to 4.04). | |||||
| Sulheim et al16 | Ski and snowboard | Case–control | 2002 winter (one season) at eight major Norwegian alpine resorts | Cases=3277 injured skiers and snowboarders | Helmet use, injury type | Head injuries: treatment by ski patrollers (n=578) | Head injury: The adjusted OR for helmet use was 0.40 (95% CI 0.30 to 0.55), and for those with more severe injuries it was 0.43 (95% CI 0.25 to 0.77). |
| Controls=2992 non-injured controls | Neck injuries: treatment by ski patrollers (n=62) | Neck injury: The adjusted OR for helmet use was 0.68 (95% CI 0.34 to 1.35), indicating an association with a lower risk of neck injuries (statistically insignificant). | |||||
| Mueller et al1 | Ski and snowboard | Case–control | 2000–2005 (five seasons) at three ski resorts in Western USA | Cases=4224 | Helmet use | Head injuries: treatment by ski patrollers (n=2537) | Head injury: The adjusted OR for helmet use was 0.85 (95% CI 0.76 to 0.93). |
| Controls=17674 | Neck injuries: treatment by ski patrollers (n=565) | Neck injury: The adjusted OR for helmet use was 0.91 (95% CI 0.72 to 1.14). | |||||
| Greve et al17 | Ski and snowboard | Retrospective cohort | Injuries that occurred from July 2002 to July 2004 retrieved from emergency department medical records at nine medical facilities in Colorado, New York and Vermont | Skiers and snowboarders who sustained a head injury as defined by International Classification of Diseases-9 codes for acute head injuries (n=1013 total patients) | Helmet use | Head injury | There was a significantly lower incidence of head injuries involving loss of consciousness in helmet users who struck a fixed object (χ2: 5.8; p<0.05). |
| Sacco et al20 | Ski and snowboard | Retrospective cohort | Injuries that occurred from January 1990 to December 1995 at Vermont, USA | Medical records of a single paediatric and adult Level 1 trauma centre were evaluated with admissions for injuries caused by alpine skiing or snowboarding (n=279) | Helmet use | Head injury | Helmets were not worn by those sustaining head injuries (n=19) or fatalities (n=26). |
| Fukuda et al18 | Snowboard | Case-series | December 1999 to March 2003 (four seasons) at Uonuma ski resort, Niigata, Japan | 1190 consecutive patients who experienced head injury during snowboarding and consulted Saito Memorial Hospital | Helmet use, knit cap use | Serious head injuries requiring medical attention (n=549) | No significant association between helmet or knit cap wearing and the occurrence of serious head injury (p=0.056) |
| Bridges et al22 | Ski, snowboard, snowblade | Case-series | 1999–2000 (one season) at Mont Tremblant, Quebec, Canada | All participants who presented with themselves to the ski patrol with traumatic injury related to their sport (n=162) | Helmet use | Head injury, neck injury, lower-extremity injuries | Head injury: Concussions represented 11% of all injuries. |
| Neck injury: There was no increase in neck injury related to helmet use. | |||||||
| Machold et al19 | Snowboard | Cross-sectional | Winter season of 1996/1997 in Austria | Of 7221 students participating in winter sport programmes organised by Austrian schools, 2745 of those riding snowboards were asked to fill out questionnaires; 2579 snowboarders replied | NA | NA | Head injury: A total of 196 snowboarders (7.6%) wore a helmet. In this group, no head injury occurred. |
| Ekeland and Rødven21 | Ski and snowboard | Case-series | 1996–1998 (two seasons) at seven major Norwegian ski resorts | A total of 3915 injuries and 32.894 million lift transports were recorded during the two seasons | Helmet use | Head injury, knee injury, ankle injury, shoulder injury | Of the skiers and snowboarders suffering a head injury, only 9% wore a helmet. The percentage of uninjured skiers wearing a helmet is unknown. |