WHY you need a helmet

From ChapmanCentral

WHY you need a helmet - BeHIT propaganda leaflet

This is a leaflet from the Bicycle Helmet Initiative Trust, the single-issue pressure group promoting compulsory use of bicycle helmets. Some sections of the leaflet have been toned down from the Trust’s claims elsewhere: I welcome the use of suitably cautious phrases like “may help reduce the severity of injury that may occur to your head”. This rightly implies that there is no degree of certainty in respect of such effects. Elsewhere in the leaflet, though, claims are made which are either substantially more emphatic than is justified by the available evidence; or based on out-of-date theories; or misleading in context (e.g. discussion of types of injuries well beyond the limited protective capabilities of bicycle helmets).

It is a reasonably representative example of pro-helmet propaganda, repeating several common themes, so is discussed here in some detail.

Contents 1 Section entitled “The REASON or you to wear a bicycle helmet” 2 Section “The Human Head…” 3 Section entitled “The Facts” 4 Section entitled “Darren’s Story”. 5 Section entitled “A message from […] David Coulthard”

Section entitled “The REASON or you to wear a bicycle helmet”

The claim is made that a helmet is “an effective measure that helps to reduce the risk of injury that can occur to your head/brain in the event of an accident”.

1. The use of the term brain injury without a definition is likely to mislead and to inspire unwarranted fear. In almost every study into cycle helmet effectiveness, the term brain injury refers in the main to simple concussions. A lay readership such as that for which the leaflet is intended is very unlikely to understand that.
2. A lay audience is most likely to construe “brain injury” as meaning injuries leading to permanent intellectual disablement, a type of injury which inspires fear and concern – and which is very rare. Helmets are not designed or specified to mitigate impacts severe enough to cause such injuries, so to use the term brain injury in this context is also likely to mislead.

Section “The Human Head…”

This section discusses only one source of injury causing serious or permanent intellectual disablement, skull fracture, with the clear implication that this is the major or only source of such injuries.

1. In describing only one of the potential mechanisms of brain injury, this section implies that helmets may be effective in reducing or preventing all causes of brain injury. At the very least there is a division of informed opinion on this, and as stated above it is the settled view of many that the major cause is not this type of injury. Indeed the theory of brain injury to which this section refers is considered by many to be long out-of-date; it is largely discredited^[1][2].
2. Notwithstanding the above, the illustration of a cracked eggshell refers solely to the coup / contre-coup theory of brain injury; these days it is widely believed that the major source of the most serious brain injuries is rotational or twisting forces, so-called diffuse axonal injury.
3. Notwithstanding the above, the evidence on which this claim is based is largely based on hard shell bicycle helmets. Almost all helmets now on sale are soft-shell or microshell helmets, with no scientifically proven efficacy against the injuries described^[3]

Section entitled “The Facts”

It is claimed that 100,000 children are treated in hospital annually due to a cycling accident

1. I know of no authoritative independent source for this figure; the source normally quoted is the chair of BHIT, the publishers of the leaflet.
   1. Notwithstanding the above, there is no evidence that cycling is unusually dangerous – having analysed figures for hospital admissions for children in England and Wales over a seven-year period, the major sources of hospitalisation are trips and falls.
   2. Notwithstanding the above, without context (i.e. how many are hospitalised for other causes, and the severity of the claimed injuries), the figure of 100,000 is likely to cause undue alarm and deter people from cycling, when cycling (with or without a helmet) has in fact been shown to be an activity which is more likely to extend than to shorten your life.
   3. Notwithstanding the above, the word “hospital” is almost certainly wrong; the closest I can come to this figure from an authoritative source is around 90,000 treatments, some years ago (it has been reducing steadily for many years), and refers to all treatments in hospitals, minor injury units and GP clinics; unless the figure includes only those treated at hospitals, and not at minor injury units and GP clinics, this claims is false.
2. It is claimed that 8 out of 10 young people ride bicycles; I know of no independent authority for this claim.
3. It is claimed that 60% of those injured suffer an injury to the head or face.
   1. This is typical for all impact injuries. Analysis of hospitalisation data shows no significant difference in the proportion of injuries which are head injuries between cycling and all admissions from any cause.
   2. Notwithstanding the above, the vast majority of the helmets on sale in the UK provide no protection to the face, so to include facial injuries is misleading.
4. It is claimed that head injuries are the most common form of death or permanent disability following a bicycle accident.
   1. This would be typical for all impact injuries. It is much easier to cause permanent disablement through head injury than through lower body injury.
   2. Notwithstanding the above, in terms of fatalities, head injuries currently make up around half; to claim that they are the most common cause of death is therefore misleading.
   3. Notwithstanding the above, the numbers of deaths and permanent disablements from bicycle accidents are very small in comparison to the numbers said to be participating – around ten deaths per year, for example.
   4. Notwithstanding the above, around five times as many children are hospitalised annually for serious head injury as a result of accidents sustained as pedestrians, as for cycling. The claim is therefore likely to cause undue alarm.
   5. Notwithstanding the above, in the context of helmet promotion, the idea that fatal or permanently disabling brain injuries can be prevented by cycle helmets is highly speculative. I know of no robust evidence to show any effect against such injuries, and the experience of New Zealand, where helmet use doubled in a single year to over 95% following compulsion, indicates that any claim of efficacy against serious and fatal injury is problematic to say the least.
   6. Notwithstanding the above, no cycle helmet manufacturer of which I am aware claims that their product is capable of preventing serious or fatal injury. To include serious or fatal injury is therefore inherently misleading.
5. It is claimed that the 12-16 age group is the most common to be seriously injured or killed in a bicycle accident.
   1. This is again typical for all impact injuries.
   2. Notwithstanding the above, around half of the claimed fatalities are not due to head injury at all; therefore to include fatalities is inherently misleading.
   3. Notwithstanding the above, the claim implies that riding a bicycle is unusually dangerous for this age group. I know of no independent evidence to show that this is the case. I believe the claim as stated is likely to discourage the 12-16 age group from cycling, or to encourage their parents to stop them cycling. Either of these outcomes is likely to have negative long-term health effects.
   4. Notwithstanding the above, no cycle helmet manufacturer claims efficacy against serious or fatal injury, so the claim is inherently misleading in the context of a helmet promotion leaflet.

Section entitled “Darren’s Story”.

The story is that of a child who sustained a severe brain injury in a collision with a motor vehicle. It is accompanied by a poem, allegedly written by the child, concluding “Be warned, wear a helmet and take care! Or you’ll finish up looking like me.”

1. It is claimed that he is disabled for life for lack of a helmet. This ignores a significant division of informed opinion on this issue. In particular:
   1. The claim assumes that the impact was of a type which may be mitigated by a bicycle helmet. There is evidence that the most severe brain injuries are caused by a mechanism which helmets have no power to mitigate[1].
   2. No current cycle helmets is designed or specified to be effective in collisions involving motor vehicles severe enough to cause disabling brain injury^[4].
2. There can be no guarantee that any helmet will provide meaningful protection in any collision involving a motor vehicle. To suggest that they do so is grossly irresponsible. It has been shown that children increase risk-taking in response to the perceived protection given by helmets^[5]. To imply meaningful protection against a type of collision which has the potential to (and often does) vastly exceed the protective capabilities of helmets^[6]. There can be no good outcome from giving children the false impression that cycle helmets are intended to protect against such impacts.
3. It is clear from the description of the crash that helmet promotion is not the most important lesson to be taken from this incident. First and foremost, the child freely admits to being inadequately in control of his machine. Secondly, the standard text on cycling technique recommend a road position such that a minor loss of control would probably not result in the cycle’s wheel hitting the kerb^[7]. Again, no cycle helmet is designed to protect against motor vehicle collision, and around half of children who die in bike vs. motor vehicle crashes, do not die of head injury. To concentrate on the use of protective equipment – secondary safety – rather than crash prevention is therefore misleading and irresponsible; to do so on the basis of protective equipment designed for another kind of crash altogether is grossly irresponsible.

Section entitled “A message from […] David Coulthard”

The claim is made that David Coulthard never cycles without a helmet.

1. During the campaign against a helmet law in 2004 it was noted that several images on Coulthard’s website showed him riding bicycles and a motor scooter bareheaded. The claim is dishonest.
2. Notwithstanding the above, Coulthard states that if he were taken to A&E with a head injury he would “probably” never be able to drive Formula 1 again. This is false. The vast majority of cyclists taken to A&E with head injuries are either not admitted, or released with no further treatment after a period of observation. The majority of "barin injuries" treated by A&E are simple concussions with no lasting effects.
3. Notwithstanding the above, one key reason Coulthard does not drive on a F1 circuit without a helmet is that he is not allowed to.
4. Notwithstanding the above, the parallels between Formula 1 and motor racing helmets, and cycling and cycle helmets, are not obvious. In particular, the amount of physical effort expended by a Formula 1 driver in order to propel his vehicle is strictly limited.
5. If modern helmets are as comfortable as Mr Coulthard suggests, how come he apparently finds it necessary to leave his straps half undone? This is a common way of mitigating the discomfort inherent in correctly fastened helmet straps.

References:

1. ↑ The efficacy of bicycle helmets against brain injury. Curnow WJ. 2003. Accident Analysis and Prevention: 2003,35:287-292
2. ↑ Assessment of current bicycle helmets for the potential to cause rotational injury, TRL, 2007
3. ↑ The Cochrane Collaboration and bicycle helmets, W.J. Curnow, Accident Analysis & Prevention, Volume 37, Issue 3 , May 2005, Pages 569-573.>
4. ↑ CEN European Standard EN 1078, Helmets for Pedal Cyclists and for Users of Skateboards and Roller Skates, February 1997
5. ↑ 5. Mok D, Gore G, Hagel B, Mok E, Magdalinos H, Pless B. 2004. Paediatr Child Health: Vol 9 No 5 May/June 2004
6. ↑ 4 http://www.cyclehelmets.org/mf.html?1047 – the opinion of Brian Walker, one of the main testers of cycle helmets coming into the UK.
7. ↑ Cyclecraft, John Franklin, The Stationery Office 1997, ISBN 0 11 702051