'Organ donors' without helmets

tomasrojo · 29-03-2011 09:50AM

Found it!
http://www.cyclehelmets.org/1216.html

A press release[3] (removed by the authors, after the commentary on their paper was submitted for peer-review) claimed: “preliminary results of a year-long study that indicates cyclists are nearly twice as likely to suffer a brain injury if they are not wearing a bicycle helmet”. A similar, but weaker, claim was made in the published paper: “Although our data set did not find significance in relative risk of cycling without helmet (most likely due to small sample size), it did show a trend consistent with previous studies…”

To make such claims when head injury rates of non-alcohol-affected patients were 30.4% (helmeted) and 32.9% (non-helmeted) seems downright deceptive.

HivemindXX · 29-03-2011 09:54AM

ednwireland wrote: »

this made me laugh as i had been told off by someone i know for not having lights on (in daylight) because they hadnt seen me as they came over a blind crest on a country road at 80km/h, seems to me the RSA thinks that its all the cyclists fault.

obviously all my fault

Yeah... It's a pretty irritating feature of discussion I find. I will mention an incident to someone and they will thrash around looking for an excuse to blame me.

Probably the most worrying was when I phoned the guards to report a bus driver that had deliberately squeezed me againt the kerb and the first question the guard on the phone asked me was if I had any lights (at 10am on a clear Summer morning).

The most farcical one was when I was told that my bright orange jacket could easily blend in to the setting sun and make me harder to see.

While I agree that some people only see what is convenient for them to see, I still think bright clothing and lights are essential as soon as it is in any way dark (dusk, dawn, very overcast. It might make the difference between being seen and not seen. At the least it will make it more difficult for the other party to justity what happened by brushing you off as a 'ninja cyclist'.

doozerie · 29-03-2011 09:57AM

I'm actually surprised that there is any reference at all that De Indo may have drawn that headline from, however ridiculously shaky it might be. I'm not sure whether to be impressed by the fact that they don't always just arbitrarily make up their own nonsense but sometimes track down other peoples' nonsense to regurgitate. They obviously actually put a little bit of effort into the muck they peddle, bless 'em.

tomasrojo · 29-03-2011 10:16AM

I emailed the Irish Independent. Not expecting a response. The pedant in me can't let these things pass.

tomasrojo · 29-03-2011 10:19AM

HivemindXX wrote: »

While I agree that some people only see what is convenient for them to see, I still think bright clothing and lights are essential as soon as it is in any way dark (dusk, dawn, very overcast).

I agree. Though if you have very good lights the bright clothing isn't required once the sun is set.

Mucco · 29-03-2011 11:04AM

tomasrojo wrote: »

I emailed the Irish Independent. Not expecting a response. The pedant in me can't let these things pass.

The 'twice as likely to be killed' quote is from the RSA - their website refuses to load for me, but it's in their cycle safety booklet - unattributed.

unionman · 29-03-2011 11:07AM

Mucco wrote: »

The 'twice as likely to be killed' quote is from the RSA - their website refuses to load for me, but it's in their cycle safety booklet - unattributed.

Makes sense, Indo aren't in the habit of bothering their arse with a second source.

petethedrummer · 29-03-2011 11:20AM

tomasrojo wrote: »

I emailed the Irish Independent. Not expecting a response. The pedant in me can't let these things pass.

Same here, how did you contact them? I used the online query thing, which might just disappear into the ether.

tomasrojo · 29-03-2011 11:32AM

petethedrummer wrote: »

Same here, how did you contact them? I used the online query thing, which might just disappear into the ether.

independent.letters@independent.ie

It was quite hard to find that email address. I had to use google with the "site:" modifier.

tomasrojo · 29-03-2011 11:40AM

I suppose it's really the RSA who have to be contacted. If they really are taking statistics from retracted press releases, it's a very, very poor show.

Cookie_Monster · 29-03-2011 12:01PM

tomasrojo wrote: »

independent.letters@independent.ie

It was quite hard to find that email address. I had to use google with the "site:" modifier.

it's on the "contact us" page

http://www.independent.ie/service/contact-us-24070.html

tomasrojo · 29-03-2011 12:03PM

Cookie_Monster wrote: »

it's on the "contact us" page

http://www.independent.ie/service/contact-us-24070.html

Yeah, that's where Google led me. I was initially looking on the letters page. I think the Irish Times follows the same convention as the Independent though.

monument · 29-03-2011 07:04PM

irishmotorist wrote: »

I think that it is a good idea for cyclists to wear helmets. I didn't say that others should not. I stated that I thought comparing cyclists to other types of road users was not valid and this is because there are differences. You ask specifically about pedestrians. Well, pedestrians have their own space - the footpath. They are not regularly travelling at 20/30/40km/h on a shared surface with cars. These are differences that make this comparison useless, IMO. I think that the shared space and my speed on a bike give bigger risk. If something happens to me or I make a mistake at that speed, I think that I have a bigger risk of a problem than if I fell while I was walking.

Sure there are differences. But you're making a lot of assumptions. There's no evidence to show that cyclists are at greater risk of head or brain injury.

The "pedestrians have their own space" argument does not stack up to reality -- pedestrians get hit all the time by vehicles, from cars to cyclists to HGVs to buses. While in "their own space" pedestrians get hit by cars, cyclists and by bus mirrors, and vehicles can mount curbs with little effort when in crashes. Both cyclists and motorists break traffic lights and most road crossing (even if you exclude drive ways) do not include ped lights.

Let's take the way you look at risks and there's loads of risks while walking -- crack footpaths, slippery footpaths, narrow footpaths close to traffic, cyclists on footpaths, people who may assault you, there's people running around, people's shoes could be untied, or some body could push you on to the road or into a wall or poll. Is that a silly list? Because that's the kind of argument you're getting into when you say things like "It's the behaviour of cyclists and the people that we're near that cause all of the danger, with the minute exception of an unseen brick on the road."

The effects of mass and speed differential means that when a car hits a person walking slowly (or a cyclist going slowly) the impact may be worse off than when a cyclist is going faster and gets hits by a car going fast but with less of a speed difference. There's many other factors too -- cyclists will tend to get hit lower down, while walkers will tend to get hit full on, which increases the force of the impact for what ever part of the body hits the ground or anything else.

Most commuting cyclists don't get to 40km/h regularly -- many people here may go to those speeds and beyond, but that is not a reason to say helmets are useful generally for cyclists.

For cyclists to be at such a greater risk of head injuries than other roads users, the injury and death rate would have to be much higher. The use of helmets while cycling but not while walking does not stack up.

Do you wear a helmet while walking? Why not? There's risks!

irishmotorist wrote: »

Just on head injuries, my wife's cousin fell from a standing position (he passed out) a number of hears ago. He hit his head when he fell. After 3 days in a coma, he only recognised immediate family for the first number of weeks. Slowly things came back, but his personality and approach to life is different. He still has no sense of smell. This was a relatively simple fall but the way he hit his head, caused these problems.

On a bike, my head would be heading towards the ground at a similar speed. I'm probably unlikely to hit it in exactly the same way that he did, but I do believe that the helmet will reduce potential injuries. It won't stop them - it will reduce them.

Surly your example here means helmets will reduce potential injuries from people walking around too? And if people wore them in the city late at night it would also reduce potential injuries from potential assaults?

irishmotorist · 29-03-2011 07:37PM

I think we just have different viewpoints and we aren't going to convince each other that our view is correct. I'll leave it at this so.

From the point of view of this overall discussion, I don't care if pedestrians are at high/low/similar risk. I see that as a different discussion and not too relevant to this one. Walking on a footpath is different to cycling on a road. I think that cycling at speed (even a general commuter speed of 20km/h) carries more chance of mishap than walking at 3 or 4 km/h. As speed increases, reaction times are lengthened. Changing direction, decelerating etc. are slower the faster you are going.

There are risks involved every time we step outside the door. My personal experience as an adult tells me that I'm more likely to have to react quickly to avoid problems when I'm on a bike than when I'm on foot. I personally think that my speed, size and relative silence are the main reasons for this (people stepping without looking, drivers turning without looking etc.) Because of this increased risk, I believe that wearing a helmet on the bike is a good way to provide some protection to my most important asset.

Iwannahurl · 29-03-2011 08:20PM

Mucco wrote: »

The 'twice as likely to be killed' quote is from the RSA - their website refuses to load for me, but it's in their cycle safety booklet - unattributed.

It's from the RSA's own analysis, using Garda records.

BostonB · 29-03-2011 08:48PM

irishmotorist wrote: »

I think we just have different viewpoints and we aren't going to convince each other that our view is correct. I'll leave it at this so....

You're obviously entitled to your opinion or to rely on your own experience. Indeed your own experience, my buck the general trend because of something you do, perhaps cycling along the M50, to use an extreme example to illustrate that.

But however I think the problem with the general reporting on this issue, is that is generally flawed. But most people accept it at face value with out really questioning it. Theres a lot of lazy journalists and papers out there happy, to repeat other peoples lazy reporting.

monument · 29-03-2011 08:50PM

irishmotorist wrote: »

I think we just have different viewpoints and we aren't going to convince each other that our view is correct. I'll leave it at this so.

Ok, but that's not what you are doing...

irishmotorist wrote: »

From the point of view of this overall discussion, I don't care if pedestrians are at high/low/similar risk. I see that as a different discussion and not too relevant to this one. Walking on a footpath is different to cycling on a road. I think that cycling at speed (even a general commuter speed of 20km/h) carries more chance of mishap than walking at 3 or 4 km/h. As speed increases, reaction times are lengthened. Changing direction, decelerating etc. are slower the faster you are going.

There are risks involved every time we step outside the door. My personal experience as an adult tells me that I'm more likely to have to react quickly to avoid problems when I'm on a bike than when I'm on foot. I personally think that my speed, size and relative silence are the main reasons for this (people stepping without looking, drivers turning without looking etc.) Because of this increased risk, I believe that wearing a helmet on the bike is a good way to provide some protection to my most important asset.

You clearly do care if pedestrians are at a high/low/similar risk, otherwise you would not be trying to make arguments claiming that cyclists are at greater risks.

You're doing this with little or no evidence to back you up. You say the extra speed of a cyclist at around 20km/h increases risk compared to a pedestrian at around 4km/h, but the extra speed could allow cyclists to get out of harms way. When getting hit by a vehicle going faster than 20km/h, closing the gap in speed difference could also lessen the impact.

For both cycling and walking the risk of getting hit or falling is low, after that the risk of injury is low again, and then the risk of serious injury is lower again. But yet you only wear a helmet for one and not the other?

tomasrojo · 31-03-2011 07:42AM

The Irish Independent did publish an edited version of my letter.

Your recent article entitled "Helmets halve risks of fatality" (Irish Independent, March 29) is inaccurate. There is no published study that makes this claim about bicycle helmets.

On a related theme, I am disappointed that the RSA has chosen not to put at the top of their cyclist safety tips -- in flashing red letters -- the advice not to pass large vehicles on the inside at junctions. They mention it, but it is very near the end of their list.

Since this is the cause of 70pc of urban cyclist deaths, it should be given top priority.

Dermot Ryan
Dublin 8

http://www.independent.ie/opinion/letters/no-study-to-back-up-bicycle-helmet-claims-2602015.html

tomasrojo · 31-03-2011 07:43AM

Iwannahurl wrote: »

It's from the RSA's own analysis, using Garda records.

I'm going to try and get the RSA data and analyse it myself. Anyone know where I can get it?

Cookie_Monster · 31-03-2011 08:18AM

tomasrojo wrote: »

I'm going to try and get the RSA data and analyse it myself. Anyone know where I can get it?

Contact the RSA would be my first point of action anyway

Doctor Bob · 31-03-2011 08:23AM

Contact the Guards too- I understand they have an Analysis Services section (or somesuch- I may have the name slightly wrong). Best to go to the horses mouth, I'd have thought.

tomasrojo wrote: »

The Irish Independent did publish an edited version of my letter.
[...]
http://www.independent.ie/opinion/letters/no-study-to-back-up-bicycle-helmet-claims-2602015.html

Do you have the original version? I'd be curious to see what they edited out.

tomasrojo · 31-03-2011 08:30AM

Doctor Bob, I'll PM you the original. Their version is better than my original. They took out a mention of the retracted press release, which is just as well, since I was wrong about that being the source of the claim.

Idleater · 31-03-2011 09:32AM

For another slight tangent, I liked this "classic" comic that my iGoogle page showed me today:

There are a few other classic "helmet debate" strips in the yehuda catalogue.

doozerie · 31-03-2011 03:23PM

This is a bit off-topic but I'll mention it here as I referred to James Cracknell in an earlier post. There is a documentary of this journey on Discovery channel tonight at 21h00 and by the looks of things his "crash" will be the focus of some of it so helmets are likely to be at least mentioned:

Race Across America with James Cracknell

Following the former Olympic rower as he tries to run, cycle and swim across America in just 16 days, and his subsequent path to recovery following a life-threatening head injury he sustained in the race.

petethedrummer · 31-03-2011 03:29PM

I hope he warns people against doing 5 day desert marathons after seeing the state of him in last weeks show.

tomasrojo · 06-04-2011 08:22PM

Mucco wrote: »

The 'twice as likely to be killed' quote is from the RSA - their website refuses to load for me, but it's in their cycle safety booklet - unattributed.

I finally looked into this. The RSA claim is based on Garda collision reports collected between 1997 and 2009. What the RSA did was compare the proportion of cyclists recorded as wearing a helmet who died with the proportion of cyclists recorded as not wearing a helmet who died, calculating what's called a relative risk.
http://www.rsa.ie/Documents/Press%20Office/Pedal%20cyclist%20Road%20collision%20facts%201997-2009.doc
See the table called "Pedal Cycle users involved in fatal and injury collisions classified by crash helmet usage, 1997-2009"

There were an awful lot of missing data about helmet-wearing (more below), but these were the numbers they had to use:
185 cyclists were recorded as wearing a helmet during a collision; 5 died
904 cyclists were recorded as not wearing a helmet during a collision; 51 died

So the proportion of dead cyclists without a helmet is 2.09 times the proportion of dead cyclists with a helmet. That's the source of the claim that cyclist who don't wear helmets are roughly twice as likely to die in the event of a collision.
(Actually, the claim in the document above, Pedal Cyclist Road Collision Facts 1997-2009, is "Cyclists not wearing helmet have a risk of being killed on the road that is approximately two times the risk of those wearing helmet". This isn't quite the same as what I just wrote, since they haven't estimated the likelihood of helmeted cyclists being in a collision versus the likelihood of a unhelmeted cyclist.)

The main problem with this statistic is the RSA don't mention how uncertain this relative risk of 2.09 is. There are only five dead helmet-wearing cyclists recorded, for example, so the uncertainty around the relative risk might be large.

And indeed it is. I calculated a 95% confidence interval for the relative risk (a standard expression of uncertainty in science and clinical medicine), and got a range of probable values going from 0.84 to 5.15

1.0 would mean there's no difference between the two groups, so to a statistician, there's no evidence of difference between the two groups, as 1.0 is contained within the probable range of values. If the RSA submitted this as a paper to a peer-reviewed journal, their claim wouldn't be allowed.

A striking thing about the Garda data is that the Gardaí hadn't recorded whether cyclists were wearing helmets in the majority of collisions, fatal or otherwise. It clearly isn't a high priority for them. What recording bias might lie in this and whether it would have made the ratio higher or lower than 2.09, or would have made no difference, no-one can say. But it's a very incomplete dataset.

So overall, a poor basis for their conclusions.

Iwannahurl · 06-04-2011 10:13PM

Thanks for that analysis. It's the clearest explanation of Relative Risk I've seen in quite a while.

This bit was new to me, or else I had forgotten about the principle: "1.0 would mean there's no difference between the two groups, so to a statistician, there's no evidence of difference between the two groups, as 1.0 is contained within the probable range of values."

tomasrojo · 06-04-2011 10:19PM

Iwannahurl wrote: »

Thanks for that analysis. It's the clearest explanation of Relative Risk I've seen in quite a while.

This bit was new to me, or else I had forgotten about the principle: "1.0 would mean there's no difference between the two groups, so to a statistician, there's no evidence of difference between the two groups, as 1.0 is contained within the probable range of values."

Hi Iwannahurl,

http://clinicalevidence.bmj.com/ceweb/resources/glossary.jsp

If the 95% confidence interval for a relative risk (RR) or an odds ratio (OR) crosses 1, then this is taken as no evidence of an effect.

Chips Lovell · 06-04-2011 10:21PM

OK, that went over my head.

tomasrojo · 06-04-2011 10:51PM

el tonto wrote: »

OK, that went over my head.

A confidence interval is rather like the margin of error opinion polling companies give before elections. Don't know if that makes it any clearer.

'Organ donors' without helmets

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