Helmets - the definitive thread.. ** Mod Note - Please read Opening Post **

quozl

galwaycyclist wrote: »

Just had this brought to my attention. The attention grabbing finding is that helmet wearing appears carry a slightly higher association with being treated for head injury.

This bit

No AIS 3+ head injuries were seen in helmet‐users.

seems much more attention grabbing to me.

Despite nearly 10% of participants (roughly 50) having AIS 3+ (ie serious or higher) head-injuries none were seen amongst helmet wearers. That's despite a minor - from 17% to 18% - increase in head injuries in helmet wearers.

That's shockingly supportive of helmet wearing.

tomasrojo

quozl wrote: »

This bit

seems much more attention grabbing to me.

Despite nearly 10% of participants (roughly 50) having AIS 3+ (ie severe)

Well, presumably that encompasses less than Severe: i.e.Serious, Severe, Critical and Unsurvivable.

I'd be interested to see the breakdown. Presumably they're mostly in the Serious rather than Severe category, given the distribution of these things generally.

(Also, it would be interesting to look at alcohol consumption among the cyclist before the injury was sustained. It wouldn't be the first time an alcohol effect was mistaken for a helmet effect.)

RayCun

galwaycyclist wrote: »

Just had this brought to my attention. The attention grabbing finding is that helmet wearing appears carry a slightly higher association with being treated for head injury.

That's a weird thing to highlight from the quote you post.

77 % received only AIS 1 injuries consisting of soft tissue injury, cerebral concussion and minor facial fractures. Nearly 10 % sustained AIS 3+ head injuries... No AIS 3+ head injuries were seen in helmet‐users.

So of those with head injuries, roughly equal numbers were wearing or not wearing helmets.
Of those with serious head injuries, it was all people not wearing helmets.

quozl

tomasrojo wrote: »

Well, presumably that encompasses less than Severe: i.e.Serious, Severe, Critical and Unsurvivable.

I'd be interested to see the breakdown. Presumably they're mostly in the Serious rather than Severe category, given the distribution of these things generally.

Yes, sorry. Serious+ rather than severe+, my mis-typing.

Even just the serious category is a 8-10% chance of death (http://en.wikipedia.org/wiki/Abbreviated_Injury_Scale). So even if all the AIS 3+ injuries were serious rather than higher it would still be an extraordinarily favourable result for helmet wearing.

tomasrojo

quozl wrote: »

Yes, sorry. Serious+ rather than severe+, my mis-typing.

Even just the serious category is a 8-10% chance of death (http://en.wikipedia.org/wiki/Abbreviated_Injury_Scale). So even if all the AIS 3+ injuries were serious rather than higher it would still be an extraordinarily favourable result for helmet wearing.

Fair point. If I get time I'll look into it in more detail. There are traditional confounders in these things: people on lower income and people who have been drinking are both more likely to acquire serious injuries and less likely to wear helmets. That doesn't mean they apply here, but headline figures are often misleading.

Speaking of which, this study caught my eye, mostly because it confirms my own estimation (i.e. it confirms my prejudices, I suppose):

http://link.springer.com/article/10.1007/s00068-014-0453-0

Conclusion

Bicycle helmets may have a protective effect against external head injury [fractures and scalp lesions] but its protective role for intra-cranial hemorrhage is questionable. Further studies assessing the protective role of helmets for intra-cranial hemorrhage are warranted.

(It's another study looking at cyclists admitted to hospital with injuries.)

quozl

Tomasrojo we share the same predjudices but I think you're discounting very significant figures there much too quickly.

Those are shocking figures and worth attention whether they suit our preferences or not.

Personally I much prefer the narrative that helmets are a waste of time and I do believe that the best protection for cyclists is increased numbers cycling and that if helmet use discourages that then it may even be a bad thing.

However it's hard to argue with 50 serious+ injuries for cyclists with no helmets and 0 for a similarly sized group of cyclists with helmets. Unless the entire study is somehow completely discredited which is unlikely.

It's another study to add to the weighting of both sides of the argument but it's a study with a large sample size and a very statistically significant result.

As a note there are traditional confounders on both sides - helmet wearers have been found to cycle faster in various studies. Possibly because of the magic-helmet effect or possibly because more serious (sports) cyclists are more likely to wear helmets and also cycle faster. Especially in countries with a large cycle commuting base where helmet wearing and speed in typical commuters is low.

tomasrojo

I won't dismiss it until I've read it!

This seems to be it:
http://t.co/WJiDCFb6En

Will have a look if time permits.

quozl

Reading it myself now too

To be clear this is not in relation to anything you said...

The authors actually state that the difference in head injury rates (17 and 18%) between cyclists wearing and not wearing helmets is not statistically significant. They performed a a Chi square test.

That was clear just from looking at the numbers anyway - such a tiny difference over a sample size of only 500 couldn't be statistically significant.

and as I guessed

helmet wearing rate was 26.0 % among cyclists who reported quick cycling and 12.4 % among those who stated slow cycling

So the results are even more impressive. The helmeted group with no AIS3+ injuries actually contained twice as many cyclists travelling over 20kph - the study's definition of fast cycling.

This is probably the study I've read that most strongly supports the protective value of cycling helmets and yet it was linked as a study showing that injuries occurred more in cyclists wearing helmets Abstracts can be misleading.

CramCycle

tomasrojo wrote: »

I'd be interested to see the breakdown. Presumably they're mostly in the Serious rather than Severe category, given the distribution of these things generally.

(Also, it would be interesting to look at alcohol consumption among the cyclist before the injury was sustained. It wouldn't be the first time an alcohol effect was mistaken for a helmet effect.)

Interestingly enough in another case where a cyclist died in Ireland the papers took the line about the cyclist not wearing a helmet but witnesses at the scene reported the cyclists being unsteady, and Gardai established that the victim was on his way home from the pub after what can only be described as an excess of pints. But at the time, the only mention in the paper was that there was no helmet and this was strongly indicated as the main contributing factor (also no mention of the lack of lights on the bike either).

I had been talking to two other posters about this via PM, one of whom was from the area and confirmed the story, unfortunately we can't put these details up as no one in the press thinks that version of the story is particularly interesting.

Chips Lovell

9.6% of those with head injuries had AIS 3+ injuries.

34 of those with head injuries were wearing a helmet.

If the severity of head injury between helmet wearers and non-helmet wearers were identical, you'd extrapolate that 3.26 helmet wears would have AIS 3+ injuries, i.e. 9.6% of 34 is 3.26.

Big conclusions are being drawn from very small numbers.

quozl

You're omitting that those wearing helmets had twice the reported rate of fast cycling and that fast cycling strongly correlated (Chi2, p < 0.01) with head injuries. Thus the predicted number of AIS3+ head injuries should be higher than that you give. Probably only something like 5 - as I don't want to do the maths.

That however is statistically significant. As is the difference from 3.8 to 0 in such a sample size. Values of statistical significance are chosen as guides of probability. They don't prove anything but they suggest something. The greater the significance the more strongly they suggest it.

Admittedly one study, even one with a decent sample size, does not prove anything. You would need a much larger study or many studies combined. However it's evidence to add to one side or other of the argument - towards the necessary mass of combined studies - and it is evidence for the other side of the argument than that it was originally presented as.

galwaycyclist

RayCun wrote: »

That's a weird thing to highlight from the quote you post.



So of those with head injuries, roughly equal numbers were wearing or not wearing helmets.
Of those with serious head injuries, it was all people not wearing helmets.

Yes I knew I was making myself a hostage by highlighting that. I havent read it in detail yet myself.

However the AIS3+ appear to have a stronger association with collisions with motor vehicles.

I had a quick look but I can't see if they separate out helmet v non-helmet participation with regard to collisions with motor vehicles,

If the proportion of helmet wearers in collisions with motor vehicles is markedly different (eg less) than for non-helmet wearers then the avoidance of AIS3+ may represent a different crash experience rather than any direct effect of helmets.

galwaycyclist

Also this

With 17.2 % altogether, the cycle helmet use rate among all injured bicyclists in our study was higher than 13 % reported by BASt for bicyclists in general

So helmets may be having a protective effect in crashes but at the cost of an increased risk of being in a crash at all.

tomasrojo

Oscar Gateaux wrote: »

9.6% of those with head injuries had AIS 3+ injuries.

34 of those with head injuries were wearing a helmet.

If the severity of head injury between helmet wearers and non-helmet wearers were identical, you'd extrapolate that 3.8 helmet wears would have AIS 3+ injuries, i.e. 9.6% of 34 is 3.8.

Big conclusions are being drawn from very small numbers.

9.6% of 34 is 3.264? Fair point, but the test of significance should cater for that. Somewhat anyway.

It looks at a quick glance like a good bit of work overall, but I need to read it properly. They don't directly mention gaps in the record, as far as I can see (though it is in the appendix, page 15: helmet status unknown for 58 and 49 of the head/face-injured and -non-injured respectively).

They also deliberately exclude neck injuries. That would be very interesting to see. I can see a reason to separate them out, but not to analyse them at all is a big omission.

quozl

galwaycyclist wrote: »

Also this



So helmets may be having a protective effect in crashes but at the cost of an increased risk of being in a crash at all.

For one thing helmet wearers are more likely to be travelling at higher speed in this study. So it's a bit of a cause/effect debate as I'm sure you know yourself.

Are cyclists wearing helmets more likely to be injured because they're wearing helmets or are they more likely to wear helmets because they're cycling in a manor more likely to cause injury - ie quickly.

I don't really have a stance on this. I find it very plausible that helmets can increase the risk of certain types of injuries but I also find it very plausible that fast leisure cyclists are more likely to be wearing helmets. All the cyclists I know who have been more than minorly injured while cycling have been sports cyclists wearing helmets. Being somewhat facetious, I know that I'd rather come off a bike at 15kph without a helmet than at 40kph with one!

galwaycyclist wrote:

I had a quick look but I can't see if they separate out helmet v non-helmet participation with regard to collisions with motor vehicles,

I read the whole thing but I don't recall seeing them doing that. TBF I wasn't looking out for that but it's a fair point. I doubt the effect that you wonder about is there - significantly differential rates of vehicle crash with/without helmets - but without the data I'm just speculating.

tomasrojo

It's also possible for, say, Dorothy Robinson's work to be broadly right, and for this study to be right: that is, helmet use at population level doesn't improve head-injury rate noticeably and that helmets still have a protective effect at Level 3 upwards, since serious head injuries among utility cyclists (of which Germany has very many) are actually quite rare.

Incidentally, their use of 3+ is maybe a little disingenuous, as they don't seem to have very many above 3. I suspect if they had statistical significance at 4 and above they'd have mentioned it.

quozl

tomasrojo wrote: »

It's also possible for, say, Dorothy Robinson's work to be broadly right, and for this study to be right: that is, helmet use at population level doesn't improve head-injury rate noticeably and that helmets still have a protective effect at Level 3 upwards, since serious head injuries among utility cyclists (of which Germany has very many) are actually quite rare.

Agreed.

My takeaway from the various studies I've read on this is that I want nobody else to wear a helmet because I believe that lack of helmet use encourages cycling and larger cycling numbers increases overall cycling safey, but that I want to be wearing one myself if I crash

Not really a stance I can argue for!

Chips Lovell

What I found most interesting about it was the conclusion the authors did draw:

A large proportion of cyclist head traumata are caused by single‐vehicle crashes. Analyses that are based entirely on police‐reported data tend to focus on collisions with motor‐vehicles and may overlook this fact

We do tend to focus a lot on collisions with motor vehicles but the reality is you're more likely to get a head injury wiping out on your own.

They also link cycling speed to likelihood of head injury and attribute this to the upsurge in use of electric bikes among older people, but I don't see where that conclusion is supported in the numbers.

tomasrojo

I find the use of the Greek plural of 'trauma' probably the most shocking thing in the paper. Now that's pedantic!

tomasrojo

Oscar Gateaux wrote: »

We do tend to focus a lot on collisions with motor vehicles but the reality is you're more likely to get a head injury wiping out on your own.

Definitely. True of most injuries, I guess. But how likely are such injuries to be life-changing for a utility cyclist (rather than a sports cyclist or someone being struck by a motorised vehicle)? Not very likely. [citation needed]

Beasty

tomasrojo wrote: »

Definitely. True of most injuries, I guess. But how likely are such injuries to be life-changing for a utility cyclist (rather than a sports cyclist or someone being struck by a motorised vehicle)? Not very likely. [citation needed]

Well I can balance the books on this one - one major head injury commuting before I got into cycling at a competitive level and one racing - neither involving motor vehicles and so far as I know neither became part of any police/Gardai stats (although they must have recorded some details of cause within the respective hospitals I guess)

Both were fast and both were wearing a helmet (not the same helmet I would add:pac:). All completely anecdotal mind .....

CatFromHue

It's the main reason I started wearing a helmet.

I've a road bike and going down hill on a country side road you can easily get up to 50+Km/h, hit a pot hole at that speed and you'll end up airborne.

tomasrojo

CatFromHue wrote: »

I've a road bike and going down hill on a country side road you can easily get up to 50+Km/h.

I personally just wouldn't go that fast. But I concede it's probably very exhilarating.

Snickers Man

OK so this is post number 1135 and I really can't be bothered reading ALL the others to make sure this point hasn't been made before so here goes. If it's been made already, consider it reinforcement.

I am opposed to a mandatory helmet rule for all cyclists because I believe it would have a negative effect on shared bike schemes such as Dublin Bikes. As a resident of central Dublin I make great use of this scheme and I consider it to be the biggest quality-of-life-improvement factor in the city in recent years.

But the beauty of it is spontaneity. You need to be on the other side of the city in a few minutes? Whip out your card and jump on a bike. You won't be able to do that if you have to carry a bloody helmet around with you all day.

If I was cycling 10 or 20 miles to work every day on my own bike, I probably WOULD wear a helmet. But for five-ten minute jaunts across town on clearly demarcated cycle paths (for the most part)? Hell no.

Cutting the number of cycling injuries by cutting the number of cyclists is a trivial exercise.

Compulsory hi-viz jackets after dark, now they're a different story. Maybe I should wait for the definitive "Hi Viz Thread" before commenting further. :-)


And just a thought, would this thread not benefit from a yes/no poll?

tomasrojo

Snickers Man wrote: »

Compulsory hi-viz jackets after dark, now they're a different story. Maybe I should wait for the definitive "Hi Viz Thread" before commenting further. :-)

http://www.boards.ie/vbulletin/showthread.php?t=2057136508
Have fun!

smacl

Beasty wrote: »

All completely anecdotal mind .....

There seems to be rather a lot of similar anecdotal posts from leisure cyclists on boards, who granted might like to get up a wee bit of speed on the bike every so often. One wonders is there enough to form the basis of a study based around that stratum of the cycling population? Put another way, just because Beasty should wear a helmet when cycling at speed in the lashings of rain in a pack of other cyclists hell bent on bettering one another doesn't mean that Tiny Tim needs on cycling around Marlay park

RainyDay

Beasty wrote: »

Well I can balance the books on this one - one major head injury commuting before I got into cycling at a competitive level and one racing - neither involving motor vehicles and so far as I know neither became part of any police/Gardai stats (although they must have recorded some details of cause within the respective hospitals I guess)

Both were fast and both were wearing a helmet (not the same helmet I would add:pac:). All completely anecdotal mind .....

Maybe we need to start reporting details of all collisions properly. Here's what they are up to in the UK

https://www.mysociety.org/2014/10/07/collideoscope-collating-cycle-accident-data/

Beasty

RainyDay wrote: »

Maybe we need to start reporting details of all collisions properly. Here's what they are up to in the UK

One of my accidents was in the UK. I've never seen that website and suspect a large majority of those involved in an accidents are oblivious to it. Equally as no motor vehicle was involved in either accident the police and Gardai showed little if any interest in either

Beasty

Snickers Man wrote: »

And just a thought, would this thread not benefit from a yes/no poll?

This thread was never about imposing one view over another on the subject of compulsion or indeed influencing anyone based on popular opinion. It's a neutral thread where posters can post their personal views or provide information from both sides of the debate. A poll would not be appropriate as it's effect would almost certainly be to influence some posters based on popular opinion

doozerie

quozl wrote: »

Being somewhat facetious, I know that I'd rather come off a bike at 15kph without a helmet than at 40kph with one!

I imagine a lot of people would adopt that view, it seems quite rational, but inherent in that view are lots of assumptions.

I recall being told years ago, by someone who had spent many years riding and racing motorbikes, that coming off a motorbike is fine as long as you slide. We were watching an Isle of Man TT rider sliding at high speed along the road at the time, and I was grimacing on his behalf. Obviously, motorbike racers wear very robust full-body clothing that cyclists typically don't but the same principles apply - it's the sudden stop that would worry me as regards significant head (and many other) injuries.

Until this year, the worst fall that I'd had from a bike was from an almost stationary position. I was in a car park, slowly cycling through, the ground was wet, I wasn't wearing a helmet. I took a 90-degree right turn so slowly that I was barely moving. I got out of the saddle and pressed on a pedal, and my front wheel completely went from under me. Being out of the saddle raised my head height by a bit, but I'm short, so the distance from my head to the ground was modest enough, however the force with which my head hit the ground felt huge. Even getting a hand to the ground first did little to lessen the blow to my head, such was the speed my head was moving. I discovered a long time later that I'd broken my wrist, not a serious break by any means but it's a measure of how hard my hand had hit the ground, and from a practically stationary position. I had a headache for a couple of days afterwards. Ironically, it was the kind of fall where a helmet probably has the greatest chance of working to its maximum potential, it was pretty much a replica of the kind of tests that a helmet has to undergo to meet the required safety standards.

A few months back my front wheel was completely taken out by two sliding riders near the end of a race. I was doing about 40kph at the time. I'm not entirely sure what happened next but I believe I went instantly airborne, me and my bike flipped in the air, and I came straight down on my back, mostly, and the side of my head subsequently bounced on the road too. I'm not sure whether I slid, if I did it was minimal, it was as if I'd dropped from the sky, pretty much. My helmet cracked above my ear, perhaps the thinnest part of the helmet so not too much of a surprise I guess. On balance I'm glad I had the helmet on my head (mostly because of the gravel on the ground where it hit) but I speculate that it really had little to do in those particular circumstances, my back and ribs "kindly" bore the brunt of the impact. It took about 6 weeks before I could sleep on my right side, due to the persistent pain there, it was a few months of regular treatment before my back was back to its pre-race state. It was a high speed fall that essentially mimicked my no-speed fall above.

Those are just anecdotes, they obviously prove nothing. Based on those, and other, experiences I might reason that a helmet is going to be of most use in any fall where you drop to the ground suddenly, and I might reason that this is less likely at high speed (my race crash above not being representative, in my view, I suspect most race crashes involve less sudden deceleration and more sliding). I'm clearly just speculating though, falls/collisions are unpredictable, the consequences of wearing a helmet, or not, are unpredictable. What never ceases to amaze me however is the conviction with which some people argue for or against helmets, as if the consequences of choosing to wear a helmet or not were black and white.

I don't think that any of even the reputable studies cited in this thread answer the simplistic question of whether I, or anyone else, should wear a helmet. They do demonstrate clearly though that it is a complex topic that seems to largely defy such simplification. Unfortunately that won't stop the usual misguided people (or self-righteous arses, depending on your point of view) from publicly pleading for all of us to be obliged to wear helmets, I wish they'd all just find useful hobbies instead.