Helmets have been a hot topic in the snow-sports safety forum for many years now. Initial media interest in the subject was sparked by the deaths of Sonny Bono and Michael Kennedy in 1998. Since then, many countries and ski areas have made great efforts to promote and encourage the use of helmets on the slopes (particularly amongst children). Some have even advocated enforcement by law, citing the undoubted success of earlier seat belt campaigns amongst car occupants. Most recently, the debate was reignited after the tragic death of actress Natasha Richardson (Liam Neeson's wife) whilst skiing in Canada in March 2009. In April 2009, Vail Resorts announced that from 2009/10, helmet use would be compulsory for all their employees on the snow. The latest data from the NSAA indicates that helmet use in the USA increased in the 2009/10 season to 57% of the total on slope population, with higher rates since in children and skiers/boarders over the age of 65.
To add fuel to the initial fire, the US Government got on the bandwagon and commissioned the controversial CPSC study which in January 1999 concluded that more than 7,000 head injuries on the slopes each year in the USA could be prevented or reduced in severity by the use of a helmet.
You can read this report in PDF format here. Be aware that whilst this publication has been widely quoted in many subsequent publications and on the surface seems to make a conclusive case, it has also been criticised by most leading ski injury researchers (including Bob Johnson & Rick Greenwald) as being politically motivated. As one example of skewed statistics in the report, snowboarding head injuries are quoted rather dramatically as having risen from 1000 in 1993 to 5200 in 1997 – without mentioning that the straightforward reason for this was that the total number of snowboarders on the slopes increased by at least the same % if not more.
The CPSC were also offered the head injury data collected in Vermont by Professors Shealy and Johnson - arguably a far more comprehensive set of statistics - but the CPSC declined this offer. For these reasons, most researchers in the know regard the CPSC study as being poorly designed and claim its sole objective was political - to reach the conclusions that it did regardless of the actual facts.
The American Medical Association have produced arguably a more objective assessment of helmets for snow sports - click here to read their report - "Helmets for Recreational Skiing and Other Winter Sports in Children and Adolescents". Personally, I wear a helmet myself and would always recommend (but not force) others do so too - in my opinion there is no good reason not to wear a helmet other than personal choice. However, I also agree with the AMA's conclusion that there is insufficient evidence to support mandatory wearing of helmets on the slopes. Yes, head injuries do occur and yes, helmets will help in the vast majority of head injury situations. The argument is stronger for children who are at higher generic risk of injury on the slopes. In my opinion though, the fact remains that the risk of such an injury remains too small to insist that everyone on the slopes must wear a helmet. It should remain your personal choice at the end of the day. Nevertheless, parents should think long and hard before sending their kids out on the slopes without a lid on......
Deaths and Helmets
Accurate data on traumatic deaths on the slopes is not easy to come by for many of the main ski countries in the world. The most complete publically available data that I am aware of on deaths on the slopes comes from the USA. On average over the last ten years, there have been about 39 deaths per year from snow sports (Source, NSAA March 2009). There is some year on year variation - for example, during the 2006/07 season there were 22 deaths from 55.1 million skier/snowboarder days. This gives a death rate that year of one for every 2.5 million skier days. (Source - NSAA). This compares to 37 skier and snowboarder deaths in the U.S. in 2002/03. With 57.6 million visits in 2002/2003, the death rate that year equates to one death every 1.6 million skier visits.
In a published research study of the death rates from skiing and snowboarding in US resorts from 1991/2 to 1998/9 Shealy, Ettlinger and Johnson reported 285 deaths from a total of 426.2 million participant visits (MPVs). This equates to an overall rate of 0.67 deaths per MPVs - put another way, statistically a death can be expected for every 1.49 million visits to a ski area. Interestingly, the death rate for snowboarding (0.46 per MPV) was 34% lower than that for alpine skiing (0.70 per MPV). The causes of death and the fatality rate associated with them are given in the table below (adapted from Shealy et al) :-
|Modality of death||Fatality rate per PMV||Ratio of skiing to snowboarding death rates|
|Impact -object or person||0.195||0.563||2.89 to 1|
|NARSID*||0.081||0.016||0.19 to 1|
|Impact with snow||0.081||0.085||1.05 to 1|
|Jump||0.065||0.022||0.34 to 1|
|Other||0.033||0.016||0.48 to 1|
(* NARSID = Non-Avalanche Related Snow Immersion Death - see my summary page for more details)
So the leading mechanism of death in both sports is a collision with either a static object (tree, for example) or another person. This is particularly so for skiers. This aside, snowboarders are most likely to die from a NARSID or as the result of a jump.
In the 1998/99 part of the study, Shealy and colleagues followed the deaths as they happened and found that, where the information was available, 35% of individuals who died were wearing a helmet. This is much higher than the rate of helmet use amongst the general population on the piste. Two of the deaths amongst snowboarders resulted from them being struck by young skiers wearing helmets who had jumped without being able to see where they would land.
Shealy et al conclude "...the findings are not particularly supportive of the notion that wearing helmets will significantly reduce the number of fatalities in winter snow sports". This was supported by a presentation at the last ISSS meeting by the Chief Medical Examiner for the state of Vermont, USA - Dr Paul L. Morrow. Dr Morrow was of the opinion that of 54 deaths at commercial ski areas in Vermont from 1979/80 to 1997/98, helmets would not have been of any particular value in saving any of the lives lost - as the degree of trauma simply overwhelmed any benefits that the helmet might convey in an impact. To quote Shealy et al again - a team of highly respected ski injury researchers - "On the basis of results to date, there is no clear evidence that helmets have been shown to be an effective means of reducing fatalities in alpine sports".
Its a sobering fact for example that more than half of the people involved in fatal accidents in 2008/09 at ski areas in the USA were wearing helmets at the time of the incident (Source - NSAA). As Shealy states "Even though the prevalence of helmet utilization is rising by 4 to 5 percent per year in the U.S., there has been no statistically significant observable effect on the incident of fatality."
In another recent scientific publication, Shealy and his colleagues found that the most common primary injury in ski and snowboarding fatalities is some sort of head injury – approximately 60 percent of ski fatalities involve a head injury. However, it is critical to place this into its proper context. “While some sort of head injury is usually the first listed cause of death, most of the fatalities also involve multiple, or secondary trauma sites; single causes of death are not common.” Most fatalities appear to occur under circumstances that are likely to exceed the protective capacity of current helmets designed for recreational snow sports. (Source - “Do Helmets Reduce Fatalities or merely Alter the Patterns of Death?” Shealy, J., Johnson, R., and Ettlinger, C., 2008)
The take home message is that the wearing of a helmet should not be viewed as a panacea against fatal injury and should not give the wearer a false sense of security. Carl Ettlinger - a world renowned expert in ski safety from Vermont, USA - sums up the situation when he says on his website...
"When you feel that rush of adrenalin while skiing (snowboarding), ask yourself if you would be doing what you are doing if you were not wearing a helmet. If the answer is NO, maybe you should reconsider the activity."
So, whilst helmets may help reduce the incidence of minor and moderate head injuries and lacerations they may be less able to protect the foolhardy skier who pushes his or her limits and who (inadvertently) ends up wrapping themselves around a tree at typical skiing speeds. To give a stark example, biomechanics have demonstrated that in order to protect the head against a direct impact blow at 30 mph, with currently available materials, a helmet would need to be at least 18cm thick, 50cm wide and weigh 5kg+. Hhhmm….stylish. Radar data collected from ski areas suggests most intermediate skiers regularly travel at much higher speeds than this.....
How many skiers and boarders currently wear a helmet on the slopes?
I've already commented on this, but to add a bit more meat - According to the 2009/10 NSAA National Demographic Study 57% of US skiers and boarders wore a helmet (up from 25% in 2002/03 and a 9% rise on the previous year)
♦ 77% of children aged 9 yrs or less wore a helmet
♦ In contrast, only 32% of men aged 18-22 yrs wore a helmet.
♦ Helmet usage increases with ability level - 26% of beginners wore a helmet compared to 55% of
In Switzerland, about 80% of skiers and boarders wear helmets now. In Scotland, helmet usage has also increased but to lower levels - approx 40% of the total population. However, about 70% of those aged less than 16 years now wear a helmet.
For an analysis of the possible reasons why a greater percentage of skiers and snowboarders do not wear helmets, see further down this page.
Head Injuries and helmets
So what about data regarding helmets reducing the rates and severity of head injuries?
Again, things have to be kept in perspective. Head injuries account for at most 10-20% of all injuries from snow sports - although some studies have shown higher rates in children (up to 43% in one Canadian study though I have not seen that reported anywhere else). But even taking this 43% rate coupled with the highest injury rate gives a rate for head injury of 2.4 per 1000 skier days - really very low. A more average risk would be about 0.3-0.5 per 1000 skier days. Most of these injuries are minor (usually concussion) and as I have already mentioned the bad ones are usually the result of skiing or boarding out of control.
Nakaguchi et al in 1999 published a two year prospective study of snowboarding head injuries from Nagano, Japan. The overall rates for head injury were 6.5 per 100,000 visits for snowboarders and 3.8 for skiers. Out of a total of 301 cases, 11 (9 boarders and 2 skiers) were classified as “major”, three of whom required neurosurgery and were left with residual neurological deficit.
MacNab et al in 2002 published a case-control study to determine whether wearing a helmet protected young skiers and boarders against head injury. They looked at head, face and neck injuries in those aged less than 13 years and found helmets lead to a 43% reduction in the risk of head, face and neck injuries. Furthermore, they found that no serious neck injuries occurred as the result of wearing a helmet.
In February 2005, Hagel and colleagues from Canada published a case-control study in the British Medical Journal comparing 1082 skiers and snowboarders with head or neck injuries with 3295 skiers/boarders without head or neck injuries. They found that wearing a helmet reduced the risk of a head injury overall by 29%. For those who required ambulance transport, wearing a helmet reduced the risk of head injury by 56%. 693 people had head injuries - 69,7% of which were cases of concussion. Those with head injuries were more likely to have been injured as the result of a collision or jump. They found no associations between wearing a helmet and the occurrence of neck injuries.
Sulheim et al from Norway published a case-control study from 8 Norwegian resorts in 2006 to see if helmets might reduce head injury rates. The overall incidence of head injury in this study of 3277 injuries was 17.6%. They found a 53% higher incidence of head injuries amongst snowboarders compared to alpine skiers. Using a helmet reduced the risk of sustaining a head injury by 60% (Odds ratio 0.40, 95% confidence interval 0.3-0.55 for the statisticians amongst you!). They also found a trend towards a lower incidence of neck injuries amongst those wearing a helmet.
Shealy et al's 2008 publication concludes that “the salutary effect [of helmet usage] was limited to the less serious head injuries, such as scalp lacerations and mild concussions. No significant effect was noted for the more serious head injuries such as concussions more severe than mild, closed head injury, skull fracture and death due to head injury.”
Russell and colleagues in 2010 published a meta-analysis of 12 previous studies and concluded that skiers and snowboarders wearing a helmet were significantly less likely than those without a helmet to have a head injury (odds ratio 0.65, 95% confidence interval 0.55 to 0.79). In children under 13 years the odds ratio was 0.41 (0.27 to 0.59). In addition, they concluded that helmets were not associated with an increased risk of neck injury (odds ratio 0.89, 95% confidence interval 0.72-1.09).
Finally, we have some epidemiological data on the relationship between helmet use and the incidence of potentially serious head injuries (PSHI) - things like skull fractures, loss of consciousness, bleeding within the brain etc.
Jake Shealy from Vermont presented (as yet unpublished) data from their ongoing epidemiological study that specifically focussed on this question at the 19th ISSS meeting in Keystone, Colorado in May 2011.They defined potentially serious head injury (PSHI) as concussion, skull fracture, epidural/subdural bleed, neurological deficit or death from head injury. They found that from the 1995/6 season to the 2009/10 season, helmet use increased from 5 to 76%. They also found that head injuries as a % of all injuries decreased by 20% over the same time frame. The incidence of PSHI (expressed as MDBI) improved by 64% from 8775 days to 24,690 days between each PSHI as the rate of helmet use increased (p<0.01).
PSHI have fortunately been pretty rare in Scotland, probably because we don't have trees on or near our pistes to collide with or long wide slopes that maybe associated with high speed person to person collisions. Nevertheless, its no reason for complacency. Our ongoing study shows that from 1999-2008, head/face injuries accounted for just under 15% of all injuries in skiers and snowboarders with an absolute rate of 0.32 per 1000 skier days. The vast majority of injuries were minor in nature and only a few people needed transfer to hospital. None had any serious neurological complications as a result of their injury. Despite rising rates of helmet use (about 40% of all slope users currently compared to 5% in 1999, we have not seen the % of head injuries - even minor/moderate ones - decrease yet in Scotland).
Arguments for not wearing a helmet
Various reasons have been put forward to explain the resistance to wearing helmets on the slopes. I have been personally involved in several studies of this myself over the years and the reasons largely remain the same. Leaving aside issues such as personal choice, cost and availability, (neither of the latter should be issues these days) I offer a scientific response to a few of these concerns below. Of course, you will (as I have - frequently!) meet individuals who will argue strongly against the scientific evidence presented below and of course everyone is entitled to their opinion.
1. Helmets predispose the neck to a greater risk of injury
A common anti-helmet argument has been the concern that wearing a helmet may predispose the wearer to a greater risk of injury to the neck. The logic is that the increased weight of the helmet places the neck under increased strain in the event of an accident. Thankfully, the issue has been examined in both the laboratory and also out in the field. Computer simulation data presented at the 17th ISSS meeting concluded that wearing a helmet did not place additional stress on the neck. More recently, in May 2010 Brent Hagel and colleagues published the results of a 10 year case-control study looking specifically at this issue, even subdividing the risk between adults and children. They found no evidence that wearing a helmet increased the risk of a neck injury whilst skiing or snowboarding and this conclusion was supported by the subsequent meta-analysis by Russell mentioned above.
2. Helmets interfere with your vision (especially peripheral vision)
Once again, this concern has been studied and there is no evidence that wearing a helmet does interfere with the visual field of skiers or snowboarders. For example, a randomised controlled pilot study by Guedl and colleagues due to be published in 2011 found no differences in mean reaction time between people wearing a ski helmet or ski cap. Ski goggles increased the reaction time, however, so may limit the field of vision.
3. Wearing a helmet impairs your sense of hearing (and hence impending dangers)
It has also been argued that wearing a helmet may impair your sense of hearing, especially at certain frequencies which may make it difficult to hear sounds of impending danger (such as another slope user about to collide with you, initial avalanche noise etc). Avoiding collisions on the slopes is important because in general its the person being hit (not the person causing the collision) who comes off worse as they have no time to react. There is limited work on this topic - one study did suggest that ski helmets could raise the hearing threshold of frequencies between 2 kHz and 8 kHz, which are characteristic of the hissing caused by a skier or snowboarder passing closely by or breaking behind. However, there was no loss of hearing for the frequencies of the human voice and therefore warning shouts could still be heard. I am not aware of any studies that have looked at the specific issue of using an MP3 player/ipod type device whilst skiing/boarding. Arguably, this could also reduce your sense of awareness on the slopes so whilst not wishing to be a killjoy, do ensure these don't interfere with your general sense of awareness.
4. Wearing a helmet makes you take more risks
This idea is called the "risk compensation theory". Basically, the argument goes along the lines that wearing protective equipment makes the user more likely to take risks. A study of self reported behaviour found that although skiers and snowboarders who were risk takers skied faster than cautious people (53 v 45 km/h), the use of helmets was nearly equal in both groups (59.2% v 59.7%).
One study of self reported behaviour found that although skiers and snowboarders who were risk takers skied faster than cautious people (53 v 45 km/h), the use of helmets was nearly equal in both groups (59.2% v 59.7%). In addition, significantly more skilled skiers wore helmets (76.9% v 59.0%), and a similar proportion of those who did and did not wear helmets exhibited risk taking behaviour (29.8% v 30.2%). An editorial in the BMJ in 2011 by the same authors concluded that "the use of a helmet is not necessarily associated with a higher level of risk taking but primarily with a higher level of skill".
I am aware of other unpublished (and therefore arguably less reliable) data including some of our own from Scotland that does indicate an association between helmet wearing and risk taking. Anecdotally, I and my fellow patrollers have seen this happening on the slopes. Perhaps its a factor that varies from country to country and may be associated with cultural differences as much as anything else. More work is warranted on this topic and hopefully will help to clarify the issue. But the take home message has to be that wearing a helmet does not make you invincible!
Ski patrollers and helmets
An interesting study by Evans et al (International Journal of Injury Control and Safety Promotion, 2009; Volume 16(1): p9–14) questionned ski patrollers on their thoughts about helmet use. There was a strong belief that helmets protected against injury and that patrollers had an important position as role models for others on the slopes. Despite this, only 23% of nearly 100 patrollers in the study reported wearing a helmet! Perceived discomfort and interference with hearing were the commonest reasons for non-use (we have to remember that ski patrollers have to use radios and perhaps wearing a helmet interfered with this function). Interestingly, many patrollers felt that wearing a helmet encouraged recklessness on the slopes and increased the risks of injury. The study doesn't go into more details on this, but its possible many patrollers have anecdotal experience of helmets skiers and boarders taking undue risks. I am aware that several helmet manufacturers now offer helmets with integrated radio systems for professional skiers which may help allay some of the concerns of the patrol staff.
In 2011, I conducted a survey of ski patrollers in the UK to gauge their opinions on ski helmets. You will soon be able to read a summary of this work on this website.
Personal stories of injury
Every year, I receive hundreds and hundreds of emails relating to injuries sustained on the slopes. Whilst they are strictly speaking anecdotes, nevertheless many of them tell powerful and moving stories. One such email came from Claudia Currie in Canada whose son Chris sustained a serious head injury whislt skiing in 2003. He collided with a tree, was wearing a helmet and was also lucky enough to receive exemplary immediate medical attention. Chris and his family are pictured right and with their permission you can read his story by clicking here.
Risk calculation and helmet standards
So in my mind, the real issue is that of risk calculation - i.e. how likely is a head injury to occur? It would appear to be actually very low. This is the precise reason that cycle helmets have not been made compulsory in the UK - yes, they may reduce injuries but the absolute risk of getting one in the first place is relatively small and not great enough to warrant a mandatory law.
There is nevertheless a strong argument that any degree of risk that can be reduced, should be reduced. As a result, more and more skiers and snowboarders are buying helmets every year. As I stated above, about 40% of all skiers and boarders in Scotland in 2010 now wear a lid - the numbers are even higher for children. Helmet sales in virtually every other ski country have also increased year by year. It seems as if my prophesy from 2000 has finally come true... where not so long ago helmets were viewed as un-cool, the opposite is now increasingly true - wear a helmet and you are a dude! The advent of better styling, helmet cams, MP3 systems etc have all helped to make helmets more attractive to users.
Whatever helmet you end up buying - make sure you get a good fit and also buy a helmet that has meet an accepted standard for use in snow sports. As with other so-called “protective gear”, some "helmets" have not been subjected to any standardised testing. The helmet standards to look for are the Central European Standard EN1077 or the American standards ASTM 2040 or Snell RS-98.
Snell sets the toughest standard (see diagram below) and therefore helmets that meet the Snell standard have been put through more than the others - unfortunately, v. few commercially available snow sports helmets are currently Snell certified. The bottom line is that if you are going to buy a helmet, make sure it at least meets one (if not more) of these standards. That way, you know it has undergone some form of testing appropriate to its ultimate use on a ski slope. DO NOT use a bicycle helmet (or any other kind of helmet for that matter) on the slopes. The protective requirements of helmets vary depending on the use to which they are put.
These diagrams illustrate some of the differences between the three standards for snow sports helmets. You can see that Snell sets the toughest standards for impact absorption.
Recommended manufacturers include Leedom International, Boeri, Giro and Red. You can also check out a series of helmet reviews at www.skihelmets.com
We all know that rental gear tends to get abused, and rental helmets are probably no different. Leaving aside issues such as availability of appropriate sizes and helmet cleaning, what about the potential damage done to helmets by repeated rental use? Perhaps, if a helmet is dropped or knocked repeatedly, this may reduce the effectiveness of the helmet. The situation could of course be worse if the helmet was involved in an impact on the slopes but the user does not report it to the rental store. Its not an issue if the damage is obvious to the naked eye, but this may not be the case.
Thankfully, another study from ISSS 2011 attempted to examine this issue. Irv Scher and colleagues took 6 helmets that met current standards. Half of them were subjected to "pre-conditioning" whereas the others were left untouched as "new" helmets. The preconditioned helmets were dropped 30 times onto asphalt from a height of 1m, which is arguably more abuse than your avergae rental lid will endure. Both groups of helmets were then tested to ASTM standards. The results showed that there was no significant difference between the preconditioned and new helmets despite the preconditioned group having visible evidence of minor damage. Based on these results, they concluded that "average" wear and tear may not significantly reduce the effectiveness of rental helmets.
So, to conclude, I am a helmet wearer and would always recommend (but not force) others to wear one too. Although the absolute risk of a head injury (especially a serious one) is low, there is good evidence to indicate that a helmet will protect you against many of the common injuries that the head is susceptible too when on the slopes. They are especially important for children, who run a higher generic risk of snow sport injury and who aren't always as risk aware as adults. Helmets seem to have their most protective effect in incidents involving low speed impacts (below 15 mph) and for falls leading to blows to the head on the snow surface although Shealy's data now suggests they might have an influence on more serious injuries too.
If you do decide to wear a helmet, make sure it fits properly and meets one of the accepted standards for snowsports. Don't put ill fitting or hand me down helmets on children and replace any helmet that has suffered a significant impact.
There is no evidence to date that helmets predispose the wearer to a higher risk of neck injury or cause injury to others. Neither that they significantly restrict vision, hearing or general sensory awareness although anecdotally there will always be those who disagree.
Finally though, be aware that there is no conclusive scientific evidence that helmets reduce the risk of death in the event of a high speed collision with another object. Wearing a helmet does not make you invincible and should be regarded as a secondary defence against injury as it may not offer you complete protection if you have a high speed impact - so go careful, especially if there are trees on or near the pistes you're using.
Serious head injuries though are very rare and as a result in my opinion (and that of most other snow sports researchers) the overall risk does not justify a blanket law mandating their use.
Hagel BE et al. Effectiveness of helmets in skiers and snowboarders: case-control and case crossover study. BMJ. 2005 Feb 12;330(7487):345.
Macnab AJ et al. Effect of helmet wear on the incidence of head/face and cervical spine injuries in young skiers and snowboarders. Inj Prev. 2002 Dec;8(4):324-7.
Nakaguchi H et al. Snowboard head injury: prospective study in Chino, Nagano, for two seasons from 1995 to 1997. J. Trauma. 1999 Jun;46(6):1066-9.
Sulheim S et al. Helmet use and risk of head injuries in alpine skiers and snowboarders. JAMA. 295(8):919-24, 2006 Feb 22.
Hagel, BE et al. Helmet use and risk of neck injury in skiers and snowboarders. Am. J. Epidemiology. 171(10); 1134-43. May 2010.
Ruedl, G et al. Factors associated with self-reported risk-taking behaviour on ski slopes. Br. J. Sports Medicine 2010 44(3): 204-206
Russel, K et al. The effects of helmets on the risk of head and neck injuries amongst skiers and snowboarders. A meta-analysis. 2010. CMAJ. 182(4): 333-240
Tudor A. et al. Ski helmets could attenuate the sounds of danger. Clin J Sports Med 2010. 20: 173-8
Ruedl, G et al. Do ski helmets affect reaction time to peripheral stimuli? Wilderness Environ Medicine 2011 (In press)
If you or someone you know has suffered a significant head injury, click here for information on "Traumatic Brain Injury - A Survival Guide" by Dr Glen Johnson.