How did the BMA get bicycle helmets so wrong?

In 1958, the UK licensed a drug for treating morning sickness. It worked very well. The studies all showed that pregnant women suffering from morning sickness received much relief with the drug. Three years later it was withdrawn, but not before 2,000 babies were born with birth defects — 20,000 worldwide — three quarters of whom would die in infancy. The drug was, of course, thalidomide. It managed to get licensed because too many of the people studying it were focused on very specific aspects of its activity on the disease states that it was thought to treat, and too few were stepping back and looking at the big picture. It prevented morning sickness, therefore it worked — the logic of the day.

Joe’s anecdatum: In 2003, Joe, an 18 year old male, slipped on some wet stairs in a block of flats. His head fell eight feet onto the concrete floor. He was not wearing a bicycle helmet. He had a headache for the rest of the evening. He has never been diagnosed with any long-term ill-effects.

A disaster on the scale of Thalidomide can’t happen these days because the path to drug licensing forces researchers to comprehensively check all effects and outcomes of a new drug. Individual researchers will know in extravagant detail very narrow aspects of how a new drug achieves its desired effect. Some of them will know the exact rate at which it crosses the various barriers into the blood and into organs; others will know the exact chain of activation of molecules and genes within cells, down the individual amino acid residues that are modified and the exact number of seconds after the drug is administered; others will know the exact schedule and mechanism by which the drug is broken down or expelled from the body. They’ll be really excited and enthusiastic about their new drug. But when somebody steps back and points out that the drug causes heart failure, it won’t get anywhere.

But the BMA seems to forget everything it knows about testing interventions when it comes to bicycle helmets. There are some superficial differences between helmets and what we normally think of as “medical intervention”. They are a physical intervention rather than a drug — but medicine deals with and properly tests physical interventions all the time. And it’s supposed to prevent rather than treat injuries — but medicine deals with and properly tests preventative measures, including conventional drugs, all the time. There is no intrinsic reason why bicycle helmets can not be tested properly, in line with the rules that were designed to prevent another thalidomide disaster. We have the methods and the expertise.

Joe’s anecdatum: In 2009, Joe, a 23 year old male, slid on the gravel on the Greenwich Peninsula Thames Path, hitting his head on the concrete path and writing off an £800 camera lens. He was not wearing a cycle helmet. He was unhappy and was bored for several hours waiting for Lewisham Hospital to glue his face back together. He stayed home all next day. He has never been diagnosed with any long-term effects.

And yet the evidence that we have on bicycle helmets is currently in a worse state than the evidence that got thalidomide licensed. There is some (limited) evidence that in people who have had crashes, helmets reduce the rate of specific types of head injury — just as there is undisputed evidence that thalidomide is effective in relieving morning sickness. But there is also (equally limited and disputed) evidence of several different side effects — an increase in other types of injury* and an increased rate of crashes (particularly crashes with vehicles, which are more likely to have negative outcomes). And there is also evidence that helmets discourage many people from cycling* — an activity that adds many quality years to people’s lives by preventing or delaying cardiovascular disease, cancers, diabetes, depression, dementia, and all those other diseases of sedentary lifestyles. Helmets might be an effective intervention for the types of injuries they are claimed to prevent, but that would be irrelevant if, like thalidomide, they cause more problems than they solve.

Joe’s anecdata: In 1991, Joe, a 6 year old male, on separate occasions smashed his head open a door, some concrete steps, and a glass coffee table. On no occasion was he wearing a cycle helmet. He has a scar on his forehead that is almost identical to James Murdoch’s. Unlike James Murdoch, he has never been diagnosed with any other long-term impairment or ill-effects.

I’m not saying that they do. The issue is not that there is overwhelming evidence against helmets. The evidence that they are the cause of crashes and other injuries is no stronger than the evidence that they prevent head injuries. The issue is that the evidence either way is nowhere near good enough to make a recommendation. If helmets were a drug, they would be nowhere close to getting licensed right now.

Which is why British doctors should be embarrassed that the British Medical Association currently lobbies for helmets to be compulsory when riding a bicycle. Imagine if a pharmaceutical company developed a drug which, if administered before receiving a specific kind of traumatic injury, makes that injury easier to treat. Imagine doctors and medical scientists lobbying for it to be compulsory for everybody to take this drug daily, without anybody ever having checked for side-effects.

How has this situation arisen?  The policy decision has largely been made on the insistence of A&E consultants and trauma surgeons.  Consider the anonymous quotations that are scattered through the BMA’s cycling pages:

‘I have seen – in my practice and when working in A/E – quite a number of serious head injuries from children falling off bicycles. I have also seen a number of children who wore helmets who only suffered minor injury. I am convinced that helmets reduce injury.’ — GP

’I would certainly support cycle helmet wearing for cyclists. I have seen far too many young lives ruined by head injuries.’  — Consultant in Emergency Medicine

’I am an Emergency Department Consultant and a keen cyclist. I wholly agree…that we need to move to an environment where cycle helmet wearing is the norm, rather than the exception’  — Emergency Department Consultant

’As a regular commuting cyclist through twelve miles of heavy London traffic and as a Consultant Emergency Physician I whole-heartedly support the BMA’s stance on the introduction of legislation to make the wearing of helmets mandatory.’  — Consultant and Honorary Senior Clinical Lecturer in Emergency Medicine

’Over the [last] 16 years I have worked in A/E. I have dealt with hundreds of head and facial injuries, particularly in children, that could have been avoided had a cycle helmet been worn. I have also had the misfortune to deal with a number of fatalities that I believe would have been avoided by simply wearing a helmet. I firmly believe that legislation making cycle helmet usage mandatory is essential.’  — Emergency Medicine Consultant and Clinical Director

‘I have worked in emergency medicine for the last twelve years. Personally I cycle around two and a half thousand miles each year and my family are rapidly becoming keen cyclists also. Prior to working in emergency medicine, I did not routinely wear a cycle helmet.

I have seen numerous examples of patients sustaining severe head injuries from which they will never recover whilst cycling at low speed without a helmet. I have never seen this pattern of pathology in cyclists wearing helmets under these circumstances.

I am aware of the recent Cochrane review on the subject. I firmly believe that all cyclists should wear helmets. I also believe that the only way to ensure this happens is through legislation. I can see no justification for allowing this entirety predictable pattern of head injuries to persist. I strongly support the BMA position…’  — Consultant in Emergency Medicine

That’s five emergency medics and a GP, all reciting anecdotes from A&E. Nobody who specialises in, say, public health.

Emergency medics and trauma surgeons are obviously very enthusiastic about the potential to put an end to injuries, just as people who were very focused on the problem of morning sickness were excited by thalidomide. But ironically, most doctors and scientists are not very good with complexity. They are good with the intense detail of their own specialism, but when they have a problem to solve they fail to consider that there might be relevant things happening outside of their own field. When emergency medics want to solve the problem of head and brain injury, they look at those injuries in isolation from the rest of medicine. It’s not their job to think about the bigger the picture, or worry about things like side-effects.

Indeed, dare I suggest that for most working emergency medics and GPs, the science of evidence-based medicine is not their job or even a major part of their training: they only need to practice what the scientists amongst them tell them to practice; most working doctors don’t need to understand how we know their interventions work.

Which is fine. But that stuff is somebody‘s job, and somebody isn’t doing it right at the BMA.

This way of thinking about the issue — as an isolated problem of emergency medicine — is reflected all through the BMA’s bizarre “safe cycling” pages, which emphasise these individual anecdotes and opinions of doctors in that field (despite “expert opinion” being frequently out of line with the science and despite everything we know about the ability of anecdotes to lead readers astray), while failing to ever think of the issues around helmets in terms of effects and side-effects or the usual path of research that is demanded for medical interventions.

The authors of the Cochrane review on bicycle helmets say, in dismissing risk compensation, “the fundamental issue is whether or not when bicycle riders crash and hit their heads they are benefited by wearing a helmet.” This is exactly analogous to saying that “the fundamental issue is whether or not when a pregnant woman has morning sickness her symptoms are relieved by thalidomide.” That is not the fundamental issue at all. The fundamental issue with any medical intervention is whether it does more help than harm, whether it improves the length and quality of our lives, whether we are better with it or without. That the authors of a Cochrane review are allowed to get away with saying otherwise is a great failure for evidence-based medicine. That the BMA think there is sufficient grounds not merely to promote this intervention but to enforce it is an epic failure.

* I thought about posting separately on these sets of side-effects too, but those posts would have been much like the rest of this series: there’s a plausible hypothesis, there’s some evidence to support it, but the evidence has limitations. Ultimately the conclusions always are: the evidence base is nowhere near good enough to support helmet promotion, let alone legislation.

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21 responses to “How did the BMA get bicycle helmets so wrong?

  1. Pingback: Appendix: Bad Science Bingo in the BMA’s “safe cycling” pages | At War With The Motorist

  2. To judge by the anecdata I would advise that “Joe” lay off the cider… ;-)

  3. Great article. One of the things that puzzles me, though, is why doctors seem so fixated on bicycles. They endlessly call for intervention to save cyclists from themselves (including a doctor in Australia who recently called for mandatory long-sleeve-high-collar cycling jerseys to protect against skin cancer!), whilst being apparently unmoved by equally or more compelling arguments for other interventions – motoring helmets, hi-viz for pedestrians, non-slip shower surfaces and so on.
    I wrote a trio of posts that touch on this after a particularly hysterical article by a Sydney A&E doctor published in a cycling magazine; you can read them here (first one at the bottom):

  4. On the money. Well done.

  5. Nicely put.


    This is such flawed reasoning to justify helmet laws….it is astounding.

    This logic is not applied to anything else in society at all, why are bikes singled out for mandating safety equipment?

    Think of general outrage if the following scenarios were proposed:

    Mandatory hat law – “the fundamental issue is whether or not when people are out in the sun and at risk of developing skin cancer, they are benefited by wearing a hat”

    Mandatory life jacket law – “the fundamental issue is whether or not when swimmers find themselves in distress in the ocean or pool they are benefited by wearing a life jacket”

    Mandatory shoe law – “the fundamental issue is whether or not when walkers or runners step on sharp objects they are benefited by wearing a shoes.”

    and on it goes……

    But sadly I’d be willing to bet that if any of these ridiculous proposals were to somehow become a law, within a short time, there would be people with stories about how their life-jacket saved their life once, or how they once stood on glass and would have needed an amputation if they weren’t wearing shoes, etc etc.

  6. “Why are bikes singled out?” – because cycle “helmets” have managed to gain a strong foothold in the public imagination, because the public see cycling as something that’s dangerous but increasingly desirable to do. People will gladly snap up anything that will apparently make their cycling safer (I’m surprised the glove and knee pad people haven’t yet cottoned on to this).

    And because manufacturers, distributors, and bike shops make lots of money selling these over-priced expanded polystyrene mouldings (unit costs to make these things must be very low!). They also look bright and exciting in shops, much more so than brakes and tyres do.

    People won’t buy pedestrian helmets because walking is seen as a safe activity, and the same goes for car helmets.

    The sad thing is that the more people are seen wearing bike helmets, the more dangerous cycling looks. We’ve got to the point where ordinary people shout “you should wear a helmet!”, thus reinforcing the scam without the helmet manufacturers needing to do much at all.

    I wonder how long it’ll be before cycle “helmets” are seen as the scam that they are, like those static electricity strips everyone once had on their cars.

  7. “The evidence that [helmets] are the cause of crashes and other injuries is NO STRONGER [my emphasis] than the evidence that they prevent head injuries.”

    Your bias is showing here. In fact, the evidence that helmets either cause crashes or exacerbate injuries is so weak as to be almost nonexistent, whereas the evidence supporting their protective value in the most common types of crashes is quite strong. So why not say so plainly and avoid the weasel-wording? Unless, of course, you hope to mislead your readers. I trust that’s not the case.

    Don’t get me wrong: I’ve no quibble with you choosing to ride bareheaded. If you wish to incur the well-documented risks associated with (preventable) traumatic brain injury, so be it. I won’t have to change your nappies and mop your drool, after all. But at least try to put the case for helmets honestly. That’s not too much to ask, is it?

    • “So why not say so plainly and avoid the weasel-wording?”

      Because it’s just not true, I’m afraid. The evidence for and against is equally weak in the sense that neither comes anywhere close to being able to guide policy.

      The appeal to emotion in the last paragraph there is a particularly fine one. Do you mind if I use it next time I’m defending somebody’s right to climb stairs without wearing a helmet?

  8. A mandatory lifejacket law has actually emerged:

    This week, the legislative council in King County, Wash. — which includes Seattle — voted five-to-four to require that life jackets be worn by anyone and everyone “on or in a major river.”

    So there you have it. It can happen. It has happened. Failure to don an approved personal flotation device while “swimming or wading more than five feet from shore, or in water more than four feet in depth,” can get you an $86 fine.

  9. I wonder if Ed knows about the study showing that drivers leave more room when overtaking cyclists without helmets? The researcher, Dr Ian Walker, was hit twice when conducting this research – by a truck and a bus – both times when he was wearing a helmet!

    This phenomenon is known as risk compensation. It also affects cyclists. Another study found that that cyclists accustomed to wearing helmets ride significantly faster (implying greater risk tolerance) with helmets than without. This is bound to increase the risk of crashing.

    This is no different to observations of children running an obstacle course. Tripping, falling and bumping into things was 51% higher when the children wore helmets and wrist guards than without them.

    One way to determine whether increased risk compensation negates the benefits of helmets is to examine what happens when helmet laws are passed and millions of cyclists are forced to wear helmets or give up cycling. The statistics show that there was no decrease in head injuries per km cycled. Instead, other injuries per km increased. As well as risk compensation, the large reduction in cycling may have reduced Safety in Numbers – something that is also expected to increase injuries per km cycled.

    As Joe points out, the most important argument against helmet laws is that cycling adds many quality years to people’s lives by preventing or delaying cardiovascular disease, cancers, diabetes, depression, dementia, and all those other diseases of sedentary lifestyles. In Holland, mortality rates of people who don’t cycle to work are 39% higher than people who do. This research, published in 2000, was before any self-respecting Dutch commuter cyclist would even think of wearing a helmet.

    Given the huge benefits of cycling even without a helmet, and the evidence of risk compensation and reduced Safety in Numbers when helmet laws are passed, it is extraordinary that the BMA want to make cycling without a helmet illegal.

  10. Making helmets mandatory is being seen to be doing something (and make it possible to claim concern for cyclists) without having to spend anything on cycling infrastructure or upsetting car drivers “right” to exclusive use of roads. I don’t know where the BMA fits into this, unless they all drive BMWs and resent being obstructed on the road.

  11. Good article, Joe. Such (not all) doctors are indeed ignorant outside their own area of competence. Helmet advocacy, after all, represents the privatisation of road safety, where state responsibility would lead to the most obvious preventative measure – proper cycling infrastructure.

    As you say, why pick out cycling? I got food poisoning last year and banged my head on the loo doorframe whilst struggling to the toilet to throw up. If I was wearing a helmet at the time, my head injuries would have been significantly reduced. C’mon BMA, demand compulsory helmets for trips to the bog when ill. You know it makes sense.

  12. Pingback: AWWTM: How did the BMA get bicycle helmets so wrong? | Joe D

  13. Pingback: In which I have to agree with the ABD | At War With The Motorist

  14. Joe
    My concern is that all the emphasis is on helmet vs no helmet whilst there is no discussion at all about the design of the helmets. Motorbike helmets are designed using thin shell strength – just like an egg shell whereas cycling helmets have massive holes punched through them. Yes I do sweat a lot when cycling hard but is there no alternative that does not undermine the structural integrity of the helmet? I would like to see a lot more done on testing helmets and evidence to show how they stand up. Surely they could put some helmets on the car test dummies and see how they perform. I for one have never seen any evidence given by a helmet manufacturer on performance in an accident situation.

    • A motorcycle helmet is designed to protect people travelling up to 70 mph and beyond. Hence a different design.

      I’m also sure that in a head on collision with a car that a motorcyclist will be only minimally protected by the helmet (sustaining deadly injuries to other parts of the body).

      No cycle helmet manufacturer will ever say that a helmet will protect you in a collision with a vehicle. This is because they know the truth is it wouldn’t. They are designed for falls from a bike, at speeds a bike can realistically reach.

      So riding home, hit a pothole and fall to the tarmac whilst hitting your head. Then you are safer wearing a helmet.

      Get slight knocked by a car, fall over and hit the tarmac and hit your head. Then you are safer.

      Get hit by a car at 20,30 or 40 MPH then the helmet cannot protect you because it’s designed for ~12 MPH. If you get run over by a car then all bets are off.

      If I was riding down a mountain trail on a mountain bike I’d wear a helmet because I’d expect to fall off. Riding on smooth tarmac after years of experience I do not expect to fall so don’t bother.

      The people who sell these things pander to the idea (without explicitly saying) that if you get hit by a car, run over by a car, then you will survive because you have a helmet. Their design does not account for this, and in any situation involving a car the likelihood is that injuries will be to your arms legs and torso.

      • Richard Burton


        I think you’ll find that motorcycle helmets are effective up to about 16mph, as they cannot prevent the massive decelaration of the brain in the skull. The design is different to cycle helmets because motorcyclists don’t need ventilation because they aren’t exercising.

        Neither is it clear that motorcycle helmets have had a beneficial effect on the risk of dying while riding. When the motorcycle helmet law was introduced in this country, deaths to motorcyclists fell immediately, so they must work, right? Except that they mostly seemed to work between the hours of 10pm and 2am, which seems rather odd until you realise that drink driving laws were introduced at the same time. So was it likely that motorcycle helmets suddenly become effective for four hours a day, or was the drop in deaths due to motorcyclists not being drunk?

        The problem is that certain fundamentalist go-gooders get an idea and insist that a law will benefit everyone, even if they don’t like it “it’s for your own good” etc. When they do get a law passed, there is never any independent analysis of whether it had the predicted effect, but with cycle helmets the kind Aussies and Kiwis have done the experiment for us, with over twenty years of helmet laws. The result?: no proven benefit.

      • @Richard Motorcycle helmets: agree that they’re also not anything like as protective as many think. They’re also smooth to minimise the chances of sudden rotation injuries to brain and neck, and shaped to protect the neck of the wearer too. Far too heavy and hot for cycling.

        I find it interesting that in the litigation-friendly USA, you don’t need to wear a motorcycle helmet at all in Illinois, Iowa or New Hampshire. If you’re 21 or older you don’t have to wear a helmet on a motorbike in many other US states (some states require that you have health insurance). []

  15. The pro helmet lobby is highly influenced by the arguments from doctors but these have a peculiar perspective as has been pointed out.
    An experience of mine involving the son of a highly repected doctor and friend of ours many years ago illustrates this.
    As a kid I was a keen builder of model engine powered craft. Later in adulthood the doctor’s 12 year old son came over with a small aero engine he had aquired to ask my help with some fuel for it and helping him in starting it. I did this and followed up a few weeks later as to how he had got on
    His father, the doctor, had vetoed the whole project. In astonishment I asked why and was told it was because of the fire risk. This was amazing to me as I had never heard of anyone being burnt by model engine fuel and even researching this now has revealed nothing.
    I eventually understood his fathers perspective. He had been the doctor on one of Britains motor racing circuits and the smell of the burning fuel of racing cars is exactly the smell of burning model engine fuel.

  16. Pingback: Helmets in cars, helmets on bicycles | As Easy As Riding A Bike

  17. Pingback: All those helmets posts in one place | At War With The Motorist

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