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You really should wear a helmet on your bicycle

By johnboy - 7 May 2013 53

Bike helmets: an emergency doctor’s perspective

By Michael Dinh

For those working on the frontline of trauma care, the findings of a report into the protective effects of helmets in cyclists and motorcyclists published in the Medical Journal of Australia last week come as no surprise.

When an ambulance arrives at an emergency department with a cyclist injured on the road, a clinician needs to first know a few important details. How old is the patient? What are the vital signs? And finally … were they wearing a helmet?

That’s because ambulance officers, doctors and nurses have known for a long time that if a helmet is not being worn at the time a head strikes the road, pavement or cycleway, the chances of severe head injury are much higher.

Now this been shown in a one-year study I conducted, with two colleagues, of injured cyclists and motorcyclists presenting to seven major trauma centres in Sydney.

The risks of severe head injury were more than five times higher in cyclists not wearing a helmet compared to helmeted ones, and more than three times higher in motorcyclists not wearing a helmet at the time of injury.

Severe head injuries were defined as any with significant brain haemorrhage, complex skull fracture or brain swelling.

Some 70% of such patients end up on a ventilator in intensive care units; many patients with severe head injuries are left with permanent brain damage.

It’s estimated that each new case of severe brain injury costs Australia A$4.5 million.

But it’s the things that can’t be calculated that are perhaps more crippling – the long-term personality changes, the seizures, the post-traumatic adjustment, and the interminable stress on family and carers.

helmets

judy_and_ed

Conflicting studies

Australia is one of the few countries in the world with mandatory helmet laws protecting both motorcyclists and pedal cyclists.

While helmet use in motorbike riders is generally accepted, compulsory helmet laws have been resisted by many experts.

Many argue that helmet use simply deters people from dusting off their two wheelers and pedalling their way to better health.

Using a telephone survey, Professor Chris Rissel from the University of Sydney concluded that cycling rates could increase dramatically if mandatory helmet laws in Sydney were repealed.

In contrast, a recent National Heart Foundation survey showed that overall road safety, road speed and the presence of dedicated bike paths were the main obstacles limiting bicycle use.

Only 17% of respondents identified helmet use as a potential factor.

Turning the tables on rotational injury

Publicised court cases testing Australian helmet laws have even invoked limited autopsy reports hypothesising the effect of helmets imparting “rotational forces” on the brain, causing diffuse axonal injury.

Diffuse axonal injury is widespread (rather than focused) damage to the brain, and is one of the major causes of unconsciousness and persistent vegetative state following head trauma.

The argument here is helmets apparently exacerbate head injury severity by causing the head to twist quickly on impact, thus creating rotational forces on the brain.

There have been no controlled studies in the clinical setting into the association between helmet use and diffuse axonal injury – until now.

We found no reports of diffuse axonal injury in pedal cyclists, helmeted or non-helmeted, and only a marginal increase in such diagnoses in non-helmeted motorcyclists.

Definitely worth helmet hair

This Sydney-based study was the first to place motorcyclists and pedal cyclists side by side and demonstrated that the protective role of helmets in both groups are important – and even better in pedal cyclists.

Helmet hair is a small price to pay for protection. mrlerone

These results are within the range reported by a Cochrane Collaboration systematic review on the subject as well as a study of more than 13,000 pedal cyclists in France published in 2012.

Some experts against this type of observational research cite small sample sizes, and flaws inherent in case control studies, such as not being able to take into account factors such as speed and intoxication.

But it is also true that the very same type of observational study designs was the basis on which the association between smoking and lung cancer was first described.

Once you get enough studies pointing in the one direction, the signal becomes harder to refute.

If mandatory helmets are good enough for motorcyclists, they’re certainly good enough for pedal cyclists.

And as more and more people use bicycles to go to work, work up a sweat or just spend time with the kids, they can rest assured that the helmet resting comfortably on their head is doing something much more than simply disrupting their hairdo.

Michael Dinh does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations.

The Conversation

This article was originally published at The Conversation.
Read the original article.

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53 Responses to
You really should wear a helmet on your bicycle
Cantabile 12:21 pm 07 May 13

A bike helmet saved my brother’s face and possibly prevented some pretty serious head injuries as a kid, so for me it’s a non-issue.

Aeek 12:19 pm 07 May 13

I do wonder if the total lack of enforcement by Canberra policing means that a challenge along the same lines as to the Tasmanian gay laws would be successful.

DrKoresh 12:18 pm 07 May 13

@CylcingCanuckian
I’m happy to argue against the legislation of wearing helmets, but arguing that helmets don’t serve to greatly reduce serious injury in the event of a bad crash is demonstrably wrong. I don’t even understand how someone could possibly think otherwise. To say Dr Dinh is a tool of the automotive industry sounds borderline psychotic in its paranoia, especially considering how often people on bicycles have accidents that are entirely unrelated to other people’s use of cars. The recent incident where some community-spirited individual decided to spread rice on the bike path for example had nothing to do with cars or lacking bicycle infrastructure but does have a lot to do with why it’s a good idea to wear a helmet when you’re riding a bike.

I get that you’re gay for bicycles and are butt-hurt about cars, it’s a position that isn’t entirely without merit, but your reasoning in this thread is completely baffling. Blaming a doctor for promoting a public safety initiative is attacking entirely the wrong person for completely wrong reasons and only serves to demonstrate just how deluded and dogmatic you’ve become in pursuit of your agenda.

johnboy 12:13 pm 07 May 13

I have to say the handy sunshade on my helmet makes it a no brainer for me as a hat that won’t come off at speed!

PoQ 12:08 pm 07 May 13

Having crashed my car any number of times and been saved by the safety belt – buckling up is simple self preservation.

Having come off my bike any number of times, wearing a helmet is self-preservation.

As my old GP used to say, “if you need motivation to quit smoking, go visit the emphysema ward at Westmead”. Perhaps we could make tours of the trauma wards available.

The arguments against bike helmets are the same ones used against anti-smoking and for those of you who can vaguely recollect the late 1960s, anti-compulsory seat belts.

Besides, its not a question of how well or otherwise you ride your bike: it hurts the same when you fall off it when you’re in the right as it does when you’re in the wrong. And its the bloke who “oh sorry mate, I didn’t see you” who’s going to knock you off your bike and onto the ground at speed.

howeph 11:45 am 07 May 13

DrKoresh said :

howeph said :

Well I’d like to check the evidence presented but I can’t because you have to be a paid subscriber to the Medical Journal of Australia to read it.

Was this research publicly funded? If so why do I have to pay for it… again.

Because you’re paying to access the journal, not the study.

I don’t wan’t to access the journal, just the study.

Canberracanuck 11:44 am 07 May 13

@DrKoresh

Ha ha, what a clever little joke about my being Canadian. /sarcasm

As long as Dinh sides with the fear-mongers, yes, I blame him for the continued Australian addiction to cars.

@Rollersk8r

Seat belts don’t protect your head…that’s why race car drivers wear a helmet. If your 75 year old gran wants to ride a bike to the shops (which is perfectly normal in other countries) she shouldn’t have to dress like she is riding in the Tour de France

howeph 11:40 am 07 May 13

As stated above, I can’t read the study because you have to pay for it; but a key problem with the study may be selection bias [http://en.wikipedia.org/wiki/Selection_bias].

From the article “… one-year study … of injured cyclists and motorcyclists presenting to seven major trauma centres in Sydney”

Public health policy should not be based on studies conducted on very select populations – in this case only seriously ill patients arriving at major trauma centres.

Almost by definition, if you have had an accident serious enough to send you to a major trauma centre, then there is a good chance that head trauma is involved and that you would have been better off if you had been wearing a helmet when you had the accident. Hence the study shows a significant benefit, in these select circumstances (i.e. a serious accident), of wearing a helmet.

However if the study was done over the the total bike riding population (including those who have no or only minor accidents) then I suspect that the result would show that wearing a helmet has only a very small (possibly unmeasurable) effect. And it is this, possibly tiny benefit, that needs to be compared with the costs of reduced participation in cycling caused by mandatory helmet laws.

My opinion is that most forms of cycling are not the highly risky activity that Australian society seams to think it is.

A compromise should be made. I propose a change in the law for the ACT (given the ACT’ good roads and shared footpaths):

“A helmet is only mandatory if you are riding on a road with a speed limit greater or equal to 80km/h”

This law would be practical to police and would enable a simple trip to the local shops, or with the family around the lake can be done helmet free. Even my current route to commute, from Kambah to Fyshwick, would not require a helmet if I choose.

Aeek 11:36 am 07 May 13

Timing. I forgot my helmet this morning and didn’t notice until I went to take it off at work due to the winter beanie. Will take more care riding home.

Rollersk8r 11:28 am 07 May 13

Canberracanuck said :

Shall we discuss the myriad of injuries and death associated with automobiles? The reduction of brain trauma that would be caused by insisting on car drivers wearing helmets? No?

Um, there is already a mandatory safety device in all cars that almost nobody argues against – it’s called a seatbelt.

DrKoresh 10:51 am 07 May 13

Canberracanuck said :

You can push the statistics around all you want, Mr Dinh, but the fact is that, unlike Australia,most of the world “gets it”, that using a bike to get from A to B is a normal activity and doesn’t require specialised equipment. Helmets may work, but they are the product of a culture that sells fear and constantly brands the use of bicycles as a “sporting” or “leisure” activity. People need to be aware that the “convenience” of the automobile is a lie, that it marginalizes the old and the young, it has a horrific impact on the health and psychology of our society. Frightening people off their bicycles by painting vivid pictures of brain damage and insisting on armor to venture outside is not presenting a balanced argument. Shall we discuss the myriad of injuries and death associated with automobiles? The reduction of brain trauma that would be caused by insisting on car drivers wearing helmets? No? Your article merely encourages the status quo …that Austalians will continue to use their cars despite the carnage on the roads and bicycles will always be a fringe activity… unsafe and only for the physically adventurous. A little more vision is required. The use of the bicycle has to be accepted as normal, by the average citizen, by our legislators, and by our city planners,as it was before the rise in popularity of the autombile. Instead of blaming the victim, you should be berating the powers-that-be for not doing more to encourage people away from automobiles and toward public and active transport.

That’s a long bow you’re drawing there, eh? I don’t think it’s fair to blame Dr. Dinh aboot Australia’s car-culture, eh?

Holden Caulfield 10:49 am 07 May 13

Won’t somebody please think of the bells!

DrKoresh 10:49 am 07 May 13

howeph said :

Well I’d like to check the evidence presented but I can’t because you have to be a paid subscriber to the Medical Journal of Australia to read it.

Was this research publicly funded? If so why do I have to pay for it… again.

Because you’re paying to access the journal, not the study.

Canberracanuck 10:42 am 07 May 13

You can push the statistics around all you want, Mr Dinh, but the fact is that, unlike Australia,most of the world “gets it”, that using a bike to get from A to B is a normal activity and doesn’t require specialised equipment. Helmets may work, but they are the product of a culture that sells fear and constantly brands the use of bicycles as a “sporting” or “leisure” activity. People need to be aware that the “convenience” of the automobile is a lie, that it marginalizes the old and the young, it has a horrific impact on the health and psychology of our society. Frightening people off their bicycles by painting vivid pictures of brain damage and insisting on armor to venture outside is not presenting a balanced argument. Shall we discuss the myriad of injuries and death associated with automobiles? The reduction of brain trauma that would be caused by insisting on car drivers wearing helmets? No? Your article merely encourages the status quo …that Austalians will continue to use their cars despite the carnage on the roads and bicycles will always be a fringe activity… unsafe and only for the physically adventurous. A little more vision is required. The use of the bicycle has to be accepted as normal, by the average citizen, by our legislators, and by our city planners,as it was before the rise in popularity of the autombile. Instead of blaming the victim, you should be berating the powers-that-be for not doing more to encourage people away from automobiles and toward public and active transport.

howeph 10:17 am 07 May 13

Well I’d like to check the evidence presented but I can’t because you have to be a paid subscriber to the Medical Journal of Australia to read it.

Was this research publicly funded? If so why do I have to pay for it… again.

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