Category Archives: Helmets

Trying to deny that helmets can aggravate brain injury

Abstract

Several studies have reported that bicycle helmets can increase rotational acceleration. Rotational acceleration is the primary cause of brain injury.

The Australian government commissioned a study to defend its controversial helmet law. The study set up unrealistic conditions fostering low rotational acceleration. The study claims that helmets do not increase brain injury. This is deceitful. The study unrealistic conditions are not representative of real life accidents.

An interview with a study author revealed the study was not set up to address rotational acceleration. The author said:

“soft-shell helmets are for cosmetic purposes, not really for protection, …
current helmets do not appear to protect against brain injury.”

 

Look at a bicycle helmet. It has been designed with comfort in mind. It is made of light weight material that grip the road on impact rather than glance off it (as is the case with motorcycle helmets).

Helmets increase the volume of the head. In the event of an accident, this increases the risk of the head hitting the road.

The increase in the volume of the head, coupled with the gripping of the road surface, means that when a head comes into contact with the ground at speed, the head rotates quickly. This quick rotation is the main cause of brain injury.

What causes brain injury?

An old popular belief is that brain injury is caused by a direct hit the head, like a head hitting a wall, causing linear acceleration. This is focal brain injury. Bicycle helmets are designed to reduce focal injury. The polystyrene reduces linear acceleration by compressing on impact.

Scientific research done in the 1970′s has revealed that the main cause of severe brain injury is not focal injury but diffuse axonal injury:

“Protecting the brain from injury that results in death or chronic disablement provides the main motivation for wearing helmets. Their design has been driven by the development of synthetic polystyrene foams which can reduce the linear acceleration resulting from direct impact to the head, but scientific research shows that angular acceleration from oblique impulse is a more important cause of brain injury. Helmets are not tested for capacity to reduce it and, as Australian research first showed, they may increase it.

Rotational acceleration means the head turning quickly. This can create shearing inside the brain, tearing apart brain tissue. This is diffuse axonal injury. It can lead to permanent disability. This article reports from a surgeon who operates on cyclists:

” “The ones with brain swelling, that’s diffuse axonal injury, and that’s bad news” …

the whole brain is shaken up, creating many little tears in its inner structure …

Such patients undergo personality change, can contract epilepsy and have difficulty controlling their anger. They might become unemployable. Depression is a common accompaniment to brain injury. Rosenfeld sees patients’ families shattered, too. “They’re never the same. It often leads to marriage disharmony and family breakdown.” …

Rosenfeld’s opinion is candid.  “I don’t know if [helmets] do much to protect the inner part of the brain,” “

Helmets cannot protect against rotational injury but they can increase it, according to research done in Sweden:

“The non-shell helmet did in all trials grab the asphalt surface, which rotated the head together with
the helmet. The consequences were in addition to the rotating of the head, a heavily bent and compressed neck, transmitted on through the whole test dummy body after the impact.  …

This gives an average angular acceleration of 20800 rad/s² for rotating the head from 0 to 0.26 rad during the 5 ms. Löwenhielm proposes 4500 rad/s² to be the maximum angular acceleration that can be tolerated for a limited time period.”

Soft-shell helmets amplified rotational acceleration to four times higher than the tolerable maximum. Soft-shell helmets are helmets without a hard shell. They are the most common type of bicycle helmet.

On impact, the larger head volume amplifies rotational acceleration. 3cm increase in helmet circumference increases rotational acceleration by 150%:

“the 3000rad/s² to 8500rad/s² measured during abrasive and projection oblique tests with size 54cm (E) helmeted headforms. However, for the most severe cases using a size 57cm (J) headform, rotational acceleration was typically greater than 10,000rad/s² and increased to levels of 20,000rad/s², a level at which a 35% – 50% risk of serious AIS3+ injuries is anticipated.”

The difference between a helmeted and non-helmeted head is about 20cm.

In 1987, an Australian government agency released research that highlighted deficiencies with bicycle helmets:

The substantial elastic deformation of the child head that can occur during impact can result in quite extensive diffuse brain damage. It is quite apparent that the liner material in children’s bicycle helmets is far too stiff …

rotational accelerations were found to be 30% higher than those found in similar tests using a full face polymer motorcycle helmet. More work needs to be done in this area as there would seem to be a deficiency in rotational acceleration attenuation that may be the result of insufficient shell stiffness

doctor from New Zealand reports:

“cycle helmets were turning what would have been focal head injuries, perhaps with an associated skull fracture, into much more debilitating global head injuries”

In Canada, the length of stay in hospital increased increased following helmet laws, from 4.3 days to 6.9 days. The number of serious head injury admissions increased by 46%.

A strange “study”

The Australian government introduced a policy of mandatory helmets. Many people wrote to the government about brain injury from rotational acceleration. The bureaucrats claimed:

“A 2009 study by the University of NSW confirmed the effectiveness of a bicycle helmet in reducing angular acceleration and subsequent brain injury in crashes”.

This study was commissioned by the government. It was not published. After much insistence, a copy was obtained from a government agency. The abstract states that the study’s aim is to

investigate the ability of a bicycle helmet to reduce angular head acceleration“.

It seems to be a “study” with a pre-determined conclusion, like this one.

The study was set with unrealistic conditions, by

  1. Using a type of hard-shell helmet not representative of the most common type of helmet used
  2. Testing at unrealistically low speeds of 5 to 11 km/h
  3. Testing on a non-abrasive surface not representing standard road conditions
  4. Failing to test for oblique impacts (Oblique impacts generate high rotational acceleration)

Studies have reported high rotational acceleration with soft-shell helmets, at speeds above 30 km/h. This study fostered low rotational acceleration. 

The study used a helmet with a ABS shell, like the one on the right. Then it generalised its results to all bicycle helmets.

The study conclusion makes no mention of the unrealistically low speeds (5 km/h to 11 km/h). How can accident protection research only do tests a low speed? Speed is a major factor affecting impact severity. Testing only a low speeds is almost useless.

The study tested a low speeds like 5 km/h, even though the risks they are “studying” have been reported at higher speeds like 30 km/h.  The study then claimed that the risk doesn’t exist.

The conclusion fails to qualify the results by mentioning it was not using a realistic road surface. The flat surface used reduces the risk of the helmet sticking to the surface. Other studies have reported that helmets tend to stick to the road surface.

Despite the unrealistic conditions, the study claims are generalized without qualifications:

“At worst bicycle helmets do not appear to exacerbate head injury risks arising from angular acceleration.”

This is deceitful, as this claim is the result of the peculiar set up of the study. It cannot be generalised beyond the laboratory conditions.

Interview with an author of the study

CRAG has interviewed one of the study authors:

Why use hard-shell helmets?

“The helmets were supplied to us”

Why not use a soft-shell helmet, the most common type used today?

” the soft-shell helmet doesn’t do much – basically for cosmetic purposes – falls to pieces very easily – When touched can dent easily – Main function of soft shell helmets to ‘retain foam in semi-rigid format,’ not really for protection”

The tests were done at speed from 5 km/h to 11 km/h.  Why not higher speeds like 20 km/h?

“We had borrowed the RTA’s crash dummy and didn’t want to damage it”

Do you believe that the conditions used in the study are realistic of real-world conditions?

“No “

Is this study comprehensive enough to assert that helmets do not increase rotational acceleration?

the study does not address any oblique impact issues so therefore does not address potential increase in rotational acceleration of the brain

… current helmets on the market are limited in preventing rotational acceleration

… there is no rotational testing element in the helmet standard.”

In your opinion as an expert, do helmets do their job?

“As long as there is no oblique impact, yes

… But in an accident with any oblique impact, probably not

.. Current helmets do not appear to protect for brain injury such as concussion or haematoma

Ethical issues

Between 2006 & 2009, the University of NSW earned $248,000 from helmet “studies” such as this one.

This study is still not published, escaping independent scrutiny. Its purpose seems to be to defend a controversial government policy.

The government is expected to fund research to improve helmets, like it did in 1987 (before the helmet law). Commissioning research to mask deficiencies of a government policy is unethical.

The fundamental role of science is to serve the truth. It is NOT to serve the interests of the state.

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July 2013 update

The same team of researchers published a related study in 2013. It is called: “Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests“.

Like the “study” described above, this study sets up unrealistic conditions. Nothing can be concluded about real life accidents from unrealistic conditions.

Bureaucrats have peddled this study as “proof” that helmets reduce rotational acceleration.
Public money well spent?

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Helmet believers doubtful after increase in injuries

A helmet advocate researched Canadian provinces with a bicycle helmet law. What he found shocked him. Provinces with a helmet law experienced relatively more injuries.

“A study that compared six-year periods on either side of the helmet laws in the four provinces that have them calculated a reduction in fatalities of 37 per cent and a reduction in cycling of 20.5 per cent, for a net reduction in fatalities of 20.4 per cent. In provinces without helmet laws, there was a reduction of 29.5 per cent.

Other Canadian studies reports a decline in cycling and an increase in the rate of injury for children.

“Compared to adults who were not required to wear helmets, children’s cycling (<13 years) fell by 59%, with a 41% reduction for teenagers aged 13-17 …

The observed post-law number of injuries – 1676 per year – is 2.37 times higher than would have been expected for the amount of cycling.  In contrast, the safety of adult cyclists (who were not affected by the law) improved.

Thus, far from improving safety for children and teenagers, the risk of injury seems to have increased after Alberta introduced its helmet law.  Similar calculations (Tables 2 & 3), show increases in the risk of head and non-head injuries requiring ER treatment for both children and teenagers, as well as increased risk of head injuries for children, and non-head injuries for children and teenagers admitted to hospital.  In contrast, risks for adults generally decreased.”

Similar result in the US, as reported by the New York Times:

the rate of head injuries per active cyclist has increased 51 percent just as bicycle helmets have become widespread. …

the increased use of bike helmets may have had an unintended consequence: riders may feel an inflated sense of security and take more risks. …

The helmet he was wearing did not protect his neck; he was paralyzed from the neck down. …

”It didn’t cross my mind that this could happen,” said Philip, now 17.

”I definitely felt safe. I wouldn’t do something like that without a helmet.” “

A recent study in New Zealand reports a similar result:

“The New Zealand Medical Journal research found a 51 per cent drop in the average hours cycled per person from the 1989-90 period when compared to 2006-09. …

Comparing the ratio of cyclist to pedestrian injuries from 1988-91 to 2003-07 showed cyclists’  injuries more than doubled compared with pedestrians “

Similar result in Australia. Cycling decreased by 40%, the risk of injury tripled.

The most surprising outcome of bicycle helmet laws is an increase in the rate of head injuries.

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Do helmets really protect racing cyclists?

Most sport cyclists wear a helmet as it is “obvious” it protects.  Does it?

Since mandatory helmets, deaths of professional cyclists while racing have doubled:

“The helmet rule for professional cyclists was brought by the UCI in 2003 following the death of Andrei Kivlev during the Paris-Nice race.

Since then deaths of professional cyclists while racing have doubled, so where is the protection that helmets are supposed to give a rider?

It seems to me that there is too much emphasis on the part of manufacturers in designing something that looks cool rather than do what it is supposed to do, and that is protect a rider in the event he or she should hit their head.”

Dr Carwyn Hooper from St George’s University in London reports:

“Looking at evidence, it does not matter if people are wearing a helmet or not, any serious accident on a bike is likely to kill them,”

Polystyrene helmets are designed to mitigate falls below 20 km/h. Professional cyclists travel at speeds of 40 to 50 km/h, increasing to 80 km/h in downhill sections.

Why is it deemed essential that racing cyclists wear devices that are not designed to protect them? The Union Cycliste Internationale, the sport’s ruling body, first tried to impose helmets in 1991, but failed. It finally imposed them in 2003, using a tragic accident as an excuse. This opened up a new stream of sponsorship income for professional cycling.

Bicycle helmets:

  1. increase the risk of accidents
  2. increase the risk of neck injury
  3. increase the risk of brain injury

Does the protection compensates for these risks?

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Are bicycle helmets dangerous?

Abstract

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Helmets protect against minor skull injuries like bruises and lacerations.

Helmets:

  1. increase the risk of accidents
  2. increase the risk of neck injury
  3. increase the risk of brain injury
Wearing a helmet can make us feel safer.
However feeling safe is not the same as being safe

 

Some politicians claim “Helmets save lives“.

Is this true? CRAG has asked for evidence, but the government has been unable to provide any.

Even helmet salespeople do not make such claims. After being asked

Can your helmet save your life?“,

a helmet salesperson shrugged and laughed uncomfortably, before responding

Can it?” “Well, not save your life, no.

What is it that politicians know that helmet salespeople don’t?

What protection do helmets provide?

soft-shell-helmetA bicycle helmet is a piece of polystyrene covered by a layer of plastic less than 1mm thick.
It can protect in a minor accident.  However, it is not designed to protect in a serious accident.

Bicycle helmets are a piece of styrofoam designed to protect in minor impacts:

“In cases of high impact, such as most crashes that involve a motor vehicle, the initial forces absorbed by a cycle helmet before breaking are only a small part of the total force and the protection provided by a helmet is likely to be minimal in this context. In cases where serious injury is likely, the impact energy potentials are commonly of a level that would overwhelm even Grand Prix motor racing helmets. Cycle helmets provide best protection in situations involving simple, low-speed falls with no other party involved. They are unlikely to offer adequate protection in life-threatening situations.“

In serious accidents, they tend to disintegrate on impact, absorbing little energy. This crumbling is what many people mistake the helmet for as having saved their life:

“The next time you see a broken helmet, suspend belief and do the most basic check – disregard the breakages and look to see if what’s left of the styrofoam has compressed. If it hasn’t, you can be reasonably sure that it hasn’t saved anyone’s life.“

Dr Carwyn Hooper from St George’s University in London reports:

“Looking at evidence, it does not matter if people are wearing a helmet or not, any serious accident on a bike is likely to kill them,”

Bicycle helmets protect against bruises and minor lacerations.
Yet, cycling injuries tripled after Australia introduced a helmet law.

cycling_injury_rateThe rate of cycling injuries tripled after Australia introduced a helmet law.

How can the widespread wearing of helmets increase the risk of injuries?

Although helmets protect, they can also increase the risk of accidents.

Increase risk of accidents

A false sense of safety can induce people to take more risks, leading to more accidents and more injuries. This is risk compensation, a well-known safety factor:

“the law of unintended consequences is extraordinarily applicable when talking about safety innovations. Sometimes things intended to make us safer may not make any improvement at all to our overall safety”

risk-compensationRisk compensation is the tendency to take more risks when wearing safety equipment.

Wearing a helmet can induce cyclists to take more risks. This can lead to permanent disability, as reported in the New York Times:

the rate of head injuries per active cyclist has increased 51 percent just as bicycle helmets have become widespread. …

the increased use of bike helmets may have had an unintended consequence: riders may feel an inflated sense of security and take more risks. …

The helmet he was wearing did not protect his neck; he was paralyzed from the neck down. …

”It didn’t cross my mind that this could happen,” said Philip, now 17.
”I definitely felt safe. I wouldn’t do something like that without a helmet.” ”

Safety experts recognise the role of risk compensation. From the New York Times article:

”People tend to engage in risky behavior when they are protected,” he said. ”It’s a ubiquitous human trait.”

Even cyclists who discount the daredevil effect admit that they may ride faster on more dangerous streets when they are wearing their helmets.

1989 study found that helmet wearers were 7 times more likely to have accidents.

Risk compensation also affects motorists who tend to be less careful around helmeted cyclists. As reported in a study published by the University of Bath in the UK:

“Bicyclists who wear protective helmets are more likely to be struck by passing vehicles”

Children are affected by risk compensation, as reported in Accident Analysis and Prevention :

“Results indicated that children went more quickly and behaved more recklessly when wearing safety gear than when not wearing gear, providing evidence of risk compensation.”

Helmets encourage people to ride faster, as reported by the Risk Analysis international journal:

“those who use helmets routinely perceive reduced risk when wearing a helmet, and compensate by cycling faster

The severity of injuries is much higher at higher speeds.

Many people believe that helmets protect against brain injury. Do they?

What causes brain injury?

In 1960, people believed that brain injury was due to linear acceleration, from the head hitting a wall for example. This belief has shaped the design of bicycle helmets.

Since, scientific research has shown that the main cause of brain injury is diffuse injury, caused by the head turning quickly. The skull may be intact, but there can severe internal brain injury. This article reports from a surgeon who operates on cyclists:

” “The ones with brain swelling, that’s diffuse axonal injury, and that’s bad news” …

the whole brain is shaken up, creating many little tears in its inner structure …

Such patients undergo personality change, can contract epilepsy and have difficulty controlling their anger. They might become unemployable. Depression is a common accompaniment to brain injury. Rosenfeld sees patients’ families shattered, too. “They’re never the same. It often leads to marriage disharmony and family breakdown.” …

Rosenfeld’s opinion is candid. “I don’t know if [helmets] do much to protect the inner part of the brain,” “

Helmets can increase brain injury, according to this research:

“The non-shell helmet did in all trials grab the asphalt surface, which rotated the head together with
the helmet. The consequences were in addition to the rotating of the head, a heavily bent and compressed neck, transmitted on through the whole test dummy body after the impact.  …

This gives an average angular acceleration of 20800 rad/s² for rotating the head from 0 to 0.26 rad during the 5 ms. Löwenhielm proposes 4500 rad/s² to be the maximum angular acceleration that can be tolerated for a limited time period”

Helmets amplified rotational acceleration to four times higher than the tolerable maximum.

On impact, the larger head volume amplifies rotational acceleration. A 3cm increase in helmet circumference increases rotational acceleration by 150%:

“the 3000rad/s² to 8500rad/s² measured during abrasive and projection oblique tests with size 54cm (E) helmeted headforms. However, for the most severe cases using a size 57cm (J) headform, rotational acceleration was typically greater than 10,000rad/s² and increased to levels of 20,000rad/s², a level at which a 35% – 50% risk of serious AIS3+ injuries is anticipated.”

The difference between a helmeted and non-helmeted head is about 20cm.

Increase risk of the head hitting the road

In the event of an accident, helmets increase the risk of the head hitting the road.  Helmets increase the volume/size of contact area of the head. Helmeted riders are more than twice as likely to hit their head in an accident, with more impacts to the sides. Post-crash studies found that most helmets show impacts to the side,where a bare head is protected by the shoulders.

helmet-head-size-2

Helmets increase volume of the head, doubling chance of the head hitting the road in an accident;
The larger volume also amplifies rotational acceleration, the main cause of brain injury.
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A 1988 study reports that helmeted riders hit their heads seven times more often than un-helmeted riders.

Helmets are not suitable for children’s more deformable head

In 1987, the Federal Office of Road Safety published research on helmets. This research highlighted serious deficiencies with bicycle helmets:

The substantial elastic deformation of the child head that can occur during impact can result in quite extensive diffuse brain damage. It is quite apparent that the liner material in children’s bicycle helmets is far too stiff …

rotational accelerations were found to be 30% higher than those found in similar tests using a full face polymer motorcycle helmet. More work needs to be done in this area as there would seem to be a deficiency in rotational acceleration attenuation that may be the result of insufficient shell stiffness. 

child cycling 4

Bicycle helmets helmets are designed for adult heads. They are too stiff for children more deformable heads. Despite this, helmets are promoted as “protecting” children, without appropriate warnings.

Helmets are associated with more severe brain injuries

New Zealand doctor reports:

“cycle helmets were turning what would have been focal head injuries, perhaps with an associated skullfracture, into much more debilitating global head injuries”

In Canada, the length of stay in hospital increased increased following helmet laws, from 4.3 days to 6.9 days. The number of serious head injury admissions increased by 46%.

Do helmets provide a net safety benefit?

Bicycle helmets are a safety trade-off. They protect the skull against bruises and lacerations. But they increase the risk of accidents and can increase brain injury.

Evidence provided in court suggests that helmets provide limited protection.:

“So in at least one case now, a High Court has decided that the balance of probability was, in the matter before the Court, that a cycle helmet would not have prevented the injuries sustained when the accident involved simply falling from a cycle onto a flat surface, with barely any forward momentum. …

the QC … repeatedly tried to persuade the neurosurgeons … to state that one must be more safe wearing a helmet than would be the case if one were not. All three refused to do so, claiming that they had seen severe brain damage and fatal injury both with and without cycle helmets

recent meta-analysis of helmets effectiveness reports reports no net beneficial effect. They do not protect against facial injuries, and increase neck injuries.

The belief that helmets can only improve safety may be a myth:

“Bicycle helmets might not protect cyclists much at all.  And, in fact, in some cases, they might actually be more dangerous than going lidless. …

head injuries had increased even though the use of helmets had skyrocketed throughout the 1990s.  The risk of injury per cyclist had gone up by 51%. …

We don’t know what’s going on,” said one political appointee who should know.  Well, I’ll offer my idea.  People accepted the idea that helmets work, and then created studies to “prove” that they do. “

We do not know whether helmets provide a net safety benefit. We do know that injuries have increased after a helmet law was imposed in Australia. The risk of death & serious injury increased by 50% for child cyclists. 

The UK’s National Children’s Bureau provided a detailed review of cycling and helmets in 2005:

“The conclusion from the arguments outlined above is that the case for cycle helmets is far from, sound. The strong claims of injury reduction made by helmet proponents have not been borne out for fatalities (which this paper argues is the most methodologically sound test of effectiveness) in real-life settings with large populations. …

the benefits of helmets need further investigation before even a policy supporting promotion can be unequivocally supported. ….

The cycle helmet debate shows the dramatic power of real life events in shaping our understanding of causality. Tragedies happen; child cyclists are killed or left disabled for life; and we cannot let go of the belief that something 
could and should have been done to stop that particular event from happening – especially when that something is so simple as wearing a helmet. We find it hard to accept that the helmet may have made no difference. We find it harder to accept that encouraging or forcing children to wear helmets might also encourage them to ride in a more dangerous way and paradoxically to increase the risk that they will suffer an accident. And we find it much harder to accept that compulsory helmet use might put children off cycling altogether, leaving them less physically active, and – many years later – more likely to die of heart disease.Think of all the uncertainty behind that line of argument, compared with the seeming rock-solid conviction that a helmet could have saved that particular child’s life, at that particular time. And of course the fact that we are talking about children, who have a claim on our protection and who are still getting to grips with the world, makes it so much more difficult to accept the limitations on our ability to prevent them coming to harm. We cannot ignore the human suffering, pain and loss that lie behind the research and statistics. But our response to it demands reflection and perspective as well as sympathy and conviction.

Is it worth to increase the risk of brain injury to mitigate minor skull injuries? An Australian cyclist challenged a helmet fine as helmets can increase brain injury. After reviewing evidence in a court of law, NSW District Court Judge Roy Ellis concluded:

“”Having read all the material, I think I would fall down on your side of the ledger …

I frankly don’t think there is anything advantageous and there may well be a disadvantage in situations to have a helmet  and it seems to me that it’s one of those areas where it ought to be a matter of choice.

What about the studies that claim that helmets protect against 80% of head injuries?

There have been many “studies” claiming that helmets protect against brain injuries. The most famous one was done by helmet lobbyists and funded by the helmet industry. This “study” had methodological errors. It was the basis for a US government claim that helmets reduce 85% of head injuries. The US government has since dropped this claim.

Many studies assume that helmets are effective and attempt to “prove” it. Such studies jump to a predetermined conclusion, with a disturbing lack of scientific discipline. Often the claims are contradicted by the study’s own data.

Governments who enacted helmet law have funded policy-driven studies defending their policy. Such “studies” use biased statistics, resulting in misleading claims. Bill Curnow, a scientist from the CSIRO, wrote as a conclusion of a scientific article:

“Compulsion to wear a bicycle helmet is detrimental to public health in Australia but, to maintain the status quo, authorities have obfuscated evidence that shows this.”

In 2000, a government agency published a meta-analysis, that claimed to provide

overwhelming evidence in support of helmets for preventing head injury and fatal injury“.

This study was re-assessed by an independent researcher who concluded:

This paper … was influenced by publication bias and time-trend bias that was not controlled for. As a result, the analysis reported inflated estimates of the effects of bicycle helmets …

According to the new studies, no overall effect of bicycle helmets could be found when injuries to head, face or neck are considered as a whole

After attempts to justify its policy through misleading “studies”, and following CRAG submission to the Prime Minister in 2009, the federal government abandoned its compulsory helmets policy.

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Review of Evidence of the Efficacy of Helmets for Cyclists

Introduction

That the wearing of a helmet can protect cyclists from head injury might seem obvious. Measurements in laboratories have shown that helmets have the potential to do this, but, as Davis (1993) noted, the issue is what happens when the devices promoted by such research are used and adapted by real people. Research into actual use of helmets shows that the efficacy of helmets in reducing head injury is far from clear.

Interested bodies have tended to place undue credence on research findings that appear to support their own premature conclusions that helmet wearing is efficaceous. The House of Representatives Committee on Transport Safety noted in its 1985 report, hereunder HORSCOTS 1985 report, that research in which Dorsch and others found …. , see below, “has received almost universal acceptance by bicycle groups who have been working for many years to have bicycle helmets widely accepted on the basis of their effectiveness in reducing head injuries”. Similarly, despite evidence that the evidence that the efficacy of helmets was unproved, see below, the committee itself declared early in its inquiry that, “It is this committee’s belief that all cyclists should wear a helmet to increase cycling safety both on and off roads.”

An examination is made here of the evidence of the efficacy of helmet wearing which the Federal Government relied upon for its 1989 policy of compulsory helmet wearing and of evidence from later research and experience of the policy in effect. The states relied in varying degrees on the Federal Government for evidence; the Government of the ACT relied on it entirely.

1. Evidence cited

In a letter of 24 June 1992, copy attached, the Federal Office of Road Safety cited several reports as the basis for the compulsory helmets policy. Four of them argue that wearing helmets reduces head injury. They are:

1. report of the inquiry into child pedestrian and bicycle safety, Social Development Committee of the Parliament of Victoria, 1986, 1987, (the Victoria report);

2. Staysafe 12, Parliament of New South Wales, Joint Standing Committee on Road Safety, 1988 (the NSW report);

3. FORS report CR 47, Helmets for child bicyclists, some biomedical considerations, by J.C. Lane, 1986

4. FORS report CR 36, Children and road accidents, an analysis of the problems and some suggested solutions, by Barry Elliott, 1985.

Hereunder, the original research papers upon which the four reports in turn relied are listed and commented upon.

1. The Victoria report

(a) McDermott and Klug (1982) and McDermott (1984)

From statistics for Victoria, they showed that head injuries were proportionately more frequent in injured bicyclists (few of whom wore helmets) than in motorcyclists (most of whom wore helmets) despite the more severe body injuries and presumed more severe impact sustained by motorcyclists. That the benefit of helmet wearing would transfer from motorcyclists to cyclists was merely assumed, however (McDermott et al, 1993).

Comment: The second researchers listed, Dorsch et al, said “… it is of little help to compare the nature and frequency of head injuries between helmeted motorcyclists and unhelmeted bicyclists, as was done in a recent Australian study. In such a study, a host of differences between pre-crash, within-crash and post-crash factors in the two groups could contribute to erroneous conclusions about the potential protective effects of bicycle helmets.”

The submission by the Government of Victoria to the HORSCOT 1985 inquiry commented on the Dorsch study, but did not even mention McDermott or Klug.

(b) Dorsch et al (1984, 1987)

The Victoria report cited the unpublished 1984 paper. The authors introduced their published paper of 1987 with the words, “In the past, evaluation of helmet efficacy has been based on laboratory tests of limited relevance to real crashes. … Helmets for bicyclists could do much to reduce deaths and injuries among crash-involved riders. While few people would doubt this assertion, there are currently no quantitative data demonstrating the efficacy of bicycle helmets in real crashes.”

The authors sent 1321 questionnaires to members of bicycling clubs in South Australia, seeking information about their most recent crash. Out of 866 usable responses, “197 bicyclists reported a crash within the last five years in which they had struck their head or helmet. … it was estimated that the risk of death from head injury was considerably reduced for helmeted relative to unhelmeted bicyclists. … Further research is needed to confirm and refine our findings.”

Comments:

1. The authors note the popular assumption that helmets are efficaceous … “While few people would doubt this assertion“.

2. The authors themselves acknowledged limitations of their findings and the need for further research to confirm them.

3. The sample was mainly drawn from members of bicycle racing clubs, and therefore was not representative of the mostly younger and slower- moving general population of cyclists. Indeed, Dr Dorsch said in evidence to the House of Representatives Standing Committee on Road Transport Safety (HORSCOTS) inquiry (1985) on page 901(a) of evidence “One has to be very careful in making estimates of how effective universal bicycle helmet usage would be in reducing deaths and serious injuries. … people who are wearing what we regarded as the good, hard helmet … had 19 times less risk of suffering a fatal head injury. That was a hypothetical procedure. … it was based largely on an adult group of cyclists and because we went through a rather hypothetical statistical procedure to arrive at those numbers, I think one would have to be very careful in generalising those findings perhaps to very young bicyclists. … one has to be very careful in making estimates of how effective universal bicycle helmet usage would be in reducing deaths and serious injuries. In our paper we did, sure, put estimates on it but as a very hypothetical procedure. I was a bit distressed by some of the reports I had seen that suggested that 75 per cent of deaths could be prevented by everyone wearing very good, hard helmets.” She later added: “When you read those [coroners’] reports … you start to have some doubt that even the best helmets available would be as effective as we might think.”

4. In its submission to the HORSCOTS 1985 inquiry, the Government of Victoria said:

“The incidence of bicycle helmet use has not yet reached a sufficiently high level anywhere in the world for a scientific examination of helmet effectiveness in injury reduction to be undertaken. One study has examined the effectiveness of helmets on a self-reported accident basis for a small sample of users and concluded that the better hard shell helmets give greater levels of protection than inferior hard shell helmets, soft helmets or no helmet (Dorsch et al 1983) (NHMRC Road Accident Research Unit, University of Adelaide, Adelaide, 1984).” McDermott and Klug, 1982 was not even cited.

A new Australian standard, AS2063.2 adopted in 19??, after the Dorsch study, “allowed for the introduction of light-weight, well-ventilated, soft-shell helmets” (Connolly, 1991). The findings of Dorsch would not be applicable to such helmets.

5. The later researchers, Thompson et al (1989), noted the findings of Dorsch et al and added, “Because of methodologic limitations, none of the available studies have produced compelling evidence of the effectiveness of bicycle helmets.” Hillman (1993) – see below – made comments to similar effect. Wood and Milne (1986) noted that the findings of McDermott and Klug and Dorsch et al had indicated significant gains from helmet use, but pointed out that “the benefits of bicycle helmet wearing have not been proven yet using mass accident data.”

The Victoria report also says, “In an extensive analysis of children and road accidents, Elliott (1985) states that `The value and importance of pedal cyclists wearing helmets appears beyond question at this point in time'”, but Elliott relies on McDermott and Dorsch et al.

Ms C. Boughton of FORS cited Dorsch: “helmets meeting the current standard of AS2063 decrease the chance of death by a factor of 19 when compared to a person who is not wearing a helmet at all.” … “need promotion and public education campaigns to get the usage rates up to any acceptable level.”

[Following paragraph added by Peter van Schaik]
6. Another interesting point about the Dorsch study is that it found 62 per cent of cyclists who reported hitting their heads were wearing helmets at the time, but the percentage of helmet wearers would have been low. This suggests that helmeted cyclists are more likely to have an accident and/or strike their head.

2. The NSW report

The discussion of helmets in the NSW report began with the statement, “The Committee received compelling information about the need for helmets to be worn by bicyclists”, but the only evidence it cited was a finding by Healy (1985) of a 21 per cent drop in head injuries following increases in helmet wearing in Victoria.

Healy (1985): Healy merely used data from Wood and Milne. The data comprise statistics for head and other injuries to cyclists and rates of helmet wearing in Victoria in 1981-85. The numbers are small and show much year-to-year variation, and Wood and Milne denied that these data constitute proof of the benefits of helmet wearing – see their comment above.

3. FORS report CR 47

The main concern of this report, by Lane (1986), was the technical characteristics of helmets. It relied for its evaluation of efficacy on Dorsch et al and a study by Wood (1986) of bicyclist casualties in Victoria over the period 1983-86, when the use of helmets was increasing. Lane cited Wood’s data showing bicyclist casualties with head injuries declined, but there was little change in the number of other injuries. Lane concluded this was very suggestive that the observed reduction in casualties with head injuries is a consequence of increased helmet wearing. He noted, however, that it did not constitute a formal evaluation.

4. FORS report CR 36

As noted above under the Victoria report, this report by Elliott (1985) relies on McDermott and Dorsch et al.

Hillman (1993) in his report Cycle helmets, the case for and against makes a comprehensive review, in chapter 3, of research on helmet wearing and head injuries. He draws attention to difficulties and causes of uncertainty in estimating the efficacy of helmets, and shows that findings of research have varied widely. In chapter 4, Hillman questions the benefits of helmet wearing. He describes the benefits attributed to helmets as at best highly exaggerated, and says that wearing a helmet only marginally reduces the extent of head injuries following collision with a motor vehicle. (In Australia, a moving motor vehicle was involved in 92 per cent of fatal bicycle crashes in 1988 (Attewell and Dowse, 1992)).

Summary of evidence cited in support of Federal policy

Clearly, the evidence that supported the Federal Government adopting its compulsory helmets policy was flimsy. Far from being adequate to justify governments overriding individual decisions, it is hardly strong enough to support governments promoting the wearing of helmets.

2. Evidence from other studies pre-law

Wasserman et al (1986): These researchers noted that several authorities had suggested that bicyclists wear helmets but added: “few data are available to either support or refute this recommendation.” They interviewed 516 bicyclists in the USA regarding helmet use and head injuries. They expressed their findings in very cautious terms: “The findings suggest that helmets may be effective in preventing head injuries”, adding qualifications that “unmeasured variables might account for the apparent association between helmet use and protection from head injury … the results were somewhat fragile statistically … relied entirely on the interview.”

Thompson et al (1989): Their conclusions that cyclists with helmets had an 85 per cent reduction in their risk of head injury and an 88 per cent reduction in their risk of brain injury are often cited. Their case-control study, at Seattle in the USA, comprised the following, with percentages wearing helmets in brackets: 235 “case patients” with head injuries received while bicycling (7%), a control group of 433 persons with bicycling injuries not involving the head (24%) and a second control group of 558 people who had had bicycling accidents during the previous year (23%).

The authors acknowledged two sources of uncertainty: statistical error due to the fairly small sample, and bias in the sample: “We cannot completely rule out the possibility that more cautious cyclists may have chosen to wear helmets and also had less severe accidents.” Also, for the case patients a much higher proportion of crashes (22.6 per cent) was caused by contact with a moving motor vehicle than for the control groups (12.5 and 3.9 per cent respectively). Such crashes typically result in more serious injuries than crashes where no moving motor vehicle is involved.

[Following paragraph added by Peter van Schaik]
Dr. R.S.Thompson et al wrote in 1989 that bike helmets are highly effective, 85% for their group, in preventing head injuries, added that “Safety helmets are widely recommended for cyclists, but convincing evidence of their effectiveness is lacking.”

[Following paragraph added by Peter van Schaik]
McDermott et al in a Journal of Trauma report noted that Thompson’s 85% result reduces to 61% by excluding facial head injuries that a helmet would not prevent. It further notes that Thompson’s study had ten cyclists wearing helmets in the adjusted counts, a number too small to draw such a statistical conclusion. McDermott found that about 40% of bicyclist’s head injuries were reduced when using approved helmets, though injury rates increased for the neck, extremities and the pelvic region.

[Following paragraph added by Peter van Schaik]
Robinson (Head Injuries and Bicycle Helmet Laws, in press) says: “The 85% reduction in head injuries from helmet wearing in Seattle was derived mainly from a comparison of a 21.1% helmet wearing rate in a control group of children from families in a healthcare cooperative who had cycling accidents and a wearing rate of 2.1% in head injured child cyclists. However, in Seattle in May and September 1987, the same time as the investigation into helmet effectiveness at the five major teaching hospitals, the observational study (DiGuisseppi et al., 1989) found helmet wearing rates of only 3.1 and 3.3% in samples of 1957 and 2544 child cyclists. If cyclists riding around Seattle had been considered the control population, rather than those who had accidents, a rather different conclusion might have been reached about the effectiveness of helmets.”

[Following paragraph added by Peter van Schaik]
Thompson found that helmets reduce the risk of head injury by 85%, but by using the same methodology on other data in the study, it can be concluded that helmet use also reduces the risk of injury to other parts of the body by 72%.

Rodgers (1988): To examine claims that growth in the use of hard shell bicycle helmets had been successful in reducing bicycle- related head injuries and deaths, Rodgers studied over 8 million cases of injury and death to cyclists over 15 years in the USA. He concluded as follows: “There is no evidence that hard shell helmets have reduced the head injury and fatality rates. The most surprising finding is that the bicycle-related fatality rate is positively and significantly correlated with increased helmet use.” To our knowledge, Rodgers’s findings have never been challenged.

Travers Morgan (1987): Data from a questionnaire survey of bicycle crashes in Western Australia 1985-86 did “not include enough helmet wearers to assess with certainty whether head injuries are less common or less serious when a helmet is worn. … there is an indication that severe overall injuries are actually slightly more common among helmet wearers. Whilst this may not be significant, it does suggest that further research could be worthwhile” – page 35. Despite this finding, the authors recommended, on page 55, “greater initiatives should be taken to promote use of safety helmets.”

Corner et al (1987): This study of technical requirements for helmets noted that “the most life-threatening crash situation is collision with another vehicle. Other crash situations, e.g. falling from the bicycle and the like, are usually significantly less severe and require only minimal head protection.” The study recommended that helmets should be extended to protect the temporal area of the head.

Williams (1991): Helmets made to the Australian standard may fail to provide protection from 63 per cent of impacts to the head, those occurring to the temples and elsewhere below the test line for helmets. Also, where impact occurred on the ear pieces of the retention system or the rim of the helmet near the ear, wearers have suffered lacerations from the sharp edges of the ear pieces and rims.

Comment by the British Medical Association: The British Medical Association (1993) reviewed the studies of Dorsch et al, and Thompson, Rivara and Thompson and a survey in the UK by Mills (1989). The BMA’s comment was: “Although these studies provide useful preliminary data, further research is required in order that more authoritative recommendations can be made.”

[Following paragraph added by Peter van Schaik]
North et al (1993): noted in South Australia that “We have recently observed an apparent fall in the number of patients suffering from head injury due to road trauma. … The largest drop in patient numbers was observed in motor cyclists, falling from an average of 24 per year previously, to only five in 1992.” This shows that whilst head injuries to bicyclists declined dramatically after the helmets law, so did those to other road users.

[Following paragraph added by Peter van Schaik]
Pitt et al. (1994): Commented “the reason for the decrease in bicycle related head injuries is more complex than just increased wearing of helmets”.

[Following paragraph added by Peter van Schaik]
Cameron et al (1994): Interpreted the decline in percentage of head injuries in Victorian accident claims for cyclists to be purely as a consequence of increased helmet wearing. Robinson (Head Injuries and Bicycle Helmet Laws, in press) observed a similar trend for child pedestrians and cyclists in data from 1980-85, when few cyclists wore helmets. The correlation between the head injury percentages was 0.94, with P < 0.02. It is suggested that the common trend may be related to impact speed of motor vehicles. Janssen amd Wismans (1985) found that reductions in impact speeds result in greater reductions in head accelerations than for other parts of the body. The introduction of the helmets law in Victoria coincided with the introduction of major initiatives directed at drink-driving and speeding in December 1989 and March 1990, as noted by Cameron. From this it could be expected that average impact speeds in bicycle accidents would be less, and thus the percentage of head injuries would also be reduced.

Conclusion

The Federal Government’s policy on compulsory helmets was decided without sufficient knowledge of the efficacy of helmets in reducing injury to cyclists.

References

Attewell, R.G. and Dowse, M.J., Fatal crash types. Analysis of 1988 fatality file, Federal Office of Road Safety report no. CR 105, Canberra 1992

British Medical Association, Cycling towards health and safety, Oxford University Press, Oxford, New York, 1993

Corner, J.P., Whitney, C.W., O’Rourke, N. and Morgan, D.E., Motorcycle and bicycle protective helmets: requirements resulting from a post crash study and experimental research, Federal Office of Road Safety report no. CR 55, Canberra 1987

Davis, R, Death on the streets, Leading Edge Press and Publishing Ltd, Hawes, North Yorkshire, 1992

Elliott, B., Children and road accidents, FORS report CR 36, Federal Office of Road Safety, Canberra, 1985

Dorsch, M.M., evidence given to the House of Representatives Standing Committee on Transport Safety inquiry on motorcycle and bicycle helmet safety, 1985, at pages 901A and 902A

Dorsch, M.M., Wodward, A.J. and Somers, R.L., Do bicycle helmets reduce severity of head injury in real crashes?, Acc. Anal. & Prev. 19, 3, pp. 183-190, 1987

Government of Victoria: submission to the House of Representatives Standing Committee on Transport Safety inquiry on motorcycle and bicycle helmet safety, 1985, at page 1031

Healy, D., Trends in helmet usage rates and bicyclist numbers sustaining head injury – Victoria, Road Traffic Authority report 86/6, Melbourne, 1985

Hillman, M., Cycle helmets, the case for and against, Blackmore Press, Longmead, Shaftesbury, Dorset, 1993

Lane, J.C, Helmets for child bicyclists, some biomedical considerations, FORS report CR 47, Federal Office of Road Safety, Canberra, 1986

McDermott, F.T., Why pedal cyclists should wear safety helmets, Australian Family Physician, 13, 4, pp. 284-285, 1984

McDermott, F.T. and Klug, G.L., Differences in head injuries of pedal cyclists and motorcyclist casualties in Victoria, Med. J. Aust. 2:30, 1982

McDermott, F.T., Lane, J.C., Brazenor, G.A. and Debney, E.A., The effectiveness of bicyclist helmets: a study of 1710 casualties, The Journal of Trauma, 34, 6, pp. 834-845, 1993

Rodgers, G.B., Reducing bicycle accidents: a reevaluation of the impacts of the CPSC bicycle standard and helmet use, Journal of Products Liability, 11, pp. 307-317, 1988

Thompson, R.S., Rivara, F.P. and Thompson, D.C., A case-control study of the effectiveness of bicycle safety helmets, The New England Journal of Medicine, 320: 21, 1989

Travers Morgan Pty Ltd, Bicycle crashes in Western Australia 1985- 86, Federal Office of Road Safety, Canberra, 1987

Wasserman, R.C., Waller, J.A., Monty, M.J., Emery, A.B. and Robinson, D.R., Bicyclists, helmets and head injuries: a rider-based study of helmet use and effectiveness, American Journal of Public Health, 78, 9, pp. 1220-1221, 1988

Wood, T., Bicycle safety in Victoria, Proceedings Bikesafe 86 conference, Federal Office of Road Safety, Canberra, 1986

Wood, T. and Milne, P., Head injuries to pedal cyclists and the promotion of helmet use in Victoria, Australia, Acc. Anal. & Prev. 20, 3, pp. 177-185, 1988

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