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Helmets on the slopes....Heads you win?
Introduction
Deaths and helmets
Head Injuries and helmets
Risk
calculation and helmet standards
In
conclusion
References
It’s been a hot topic in the
snow-sports safety forum for best part of ten years now – the issue of
helmets. High velocity collisions with trees lead to the deaths of Sonny Bono
and Michael Kennedy in 1998 and the inevitable mass media hype – rarely a forum
for informed debate! Since then, arguments have been put forward that more
should be done to encourage the use of helmets on the slopes (particularly
children) with some advocating enforcement by law, citing the undoubted success
of earlier seat belt campaigns amongst car occupants.
To add fuel to the 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 it in PDF format here.
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Whilst this publication has been widely quoted and on the surface seems to make a conclusive case, this study has been criticised by most leading ski injury researchers (including Bob Johnson & Rick Greenwald) as being politically motivated. The statistics in it have been accused of being misleading. As one example, 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 offered data by Jake Shealy on head injuries - a far more comprehensive set of statistics - but declined the offer. For these and many other reasons, most researchers criticise the study for being poorly designed and claim its sole objective was political - to reach the conclusions that it did regardless of the actual facts.
For a far more objective assessment of helmets for snow sports - click here to read the far more balanced and objective American Medical Association's report "Helmets for Recreational Skiing and Other Winter Sports in Children and Adolescents". Personally, I agree with its conclusion that there is insufficient evidence to support mandatory wearing of helmets on the slopes. Yes, injuries may occur and yes, helmets may help reduce them. But the fact remains that the risk of such an injury is far too small to insist that everyone wears a helmet. Personal choice at the end of the day.
So let's forget the hype and hysteria and concentrate on the true facts about head injuries and helmets! Of course, there’s no denying that head injuries and related deaths do occur, but it has to be kept in perspective - traumatic deaths from skiing and snowboarding are extremely rare.
The most up to date data from the NSAA in America were released in August 2003 - 37 skiers and snowboarders died accidentally on U.S. slopes in 2002/03 compared to 45 deaths the season before. With 57.6 million visits in 2002/2003, the death rate translates to 0.64 deaths per million visits (or one death every 1.6 million skier visits - really exceptionally low). Of the fatalities, 31 were male and six female. Thirty-one were skiers and six were snowboarders.
In a recently 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 | |
| Snowboarding | Skiing | ||
| Overall | 0.455 | 0.702 | 1.54 to1 |
| 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 intro 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.
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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".
The take home
message is that the majority of those who currently wear helmets are a defined
group of younger, male and more aggressive skiers – the group well known to be
at high risk of injury anyway. Many of the high speed impacts with solid
objects lead to multiple injuries that no helmet could prevent or reduce. 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.
The situation is perhaps best summed up by Carl Ettlinger - a world renowned
expert in ski safety from Vermont, USA - 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 more minor head injuries and lacerations (especially the ones we see in Scotland) they are less able to protect the foolhardy skier who pushes his or her limits and who (inadvertently) ends up wrapping themselves around a tree. 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 between 24-38 mph.
| So what about 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. Finally, in February 2006, Sulheim et al from Norway published a case-control study from 8 Norwegian resorts 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. Serious head injuries have fortunately been extremely rare in Scotland, probably because we don't have trees on or near our pistes, although its no reason for complacency. Our ongoing study shows that from 1999-2005, 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,
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Risk calculation and helmet standards
So 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. Helmet sales in the US are increasing year by year and the same trend is likely to start being seen here. It seems as if my prophesy 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!
One of the problems is knowing which helmet to buy – as with much so-called “protective gear”, many have not been subjected to any standardised testing. The commonest standards are the Central European Standard EN1077 and UNI EN 812, but the American Snell RS-98 test standard sets more stringent targets. Unlike EN1077, Snell performs a series of impact tests and requires a higher level of impact absorption. Specifically, helmets that meet the Snell standard have to withstand at least 30% more impact force than EN1077. A newer American standard ASTM F2040 has also been introduced - nevertheless, as the diagrams below illustrate - Snell sets the toughest standards 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. Only those which have been tested specifically for snow sports will afford you the protection you require.
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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. |
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Recommended manufacturers include Leedom International, Boeri, Giro and Red. You can also check out a series of helmet reviews at www.skihelmets.com
So, to conclude, helmets are a good idea and will protect you against many of the common injuries that the head is susceptible too. They are especially important for children, who are at highest risk of snow sport injury. In addition, there is no evidence to date that helmets predispose the wearer to a higher risk of neck injury or cause injury to others. However, it must be remembered that wearing a helmet will not protect you if you have a high speed impact - so go careful, especially if there are trees near the pistes you're on.
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.
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.
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© Copyright Dr Mike Langran 1999-2008 All international rights reserved. No part of this web page may be reproduced in any form, or by any electronic, mechanical or other means, without permission in writing from Dr Langran.
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