Cycle helmets - major study

[Michael Macclan]

In message <[email protected]>, Tony Raven <[email protected]> writes
>As they point out, both sides dismiss the "evidence" and "research" of the other side. I found it a
>balanced presentation of both sides. YMMV

Well, doesn't it depend whether the dismissal of the "evidence" and "research" was preceded by
consideration? I entered the helmet debate as definitely "pro". Actually, none of the evidence and
research in favour of helmets I have seen since seems at all convincing and I have therefore shifted
my opinion towards the sceptics. I suppose the authors of the report would argue that I have
dismissed the "evidence" and "research" of the other side. So be it, but I have considered it.

John Franklin writes in "Cyclecraft", "The life-saving value of helmets is sometimes overstated,
whilst the real-life experience of countries where the wearing of helmets has become more common
suggests that, overall, head injury reduction is minimal."

I believe that Mr Franklin is something of an authority in matters of cyclist safety and his words
appear to me to sum up the helmet arguments succinctly. The question that needs to be put now is, if
helmets have only a limited effect why is there such a strong campaign going on to persuade people
to wear them. In whose interest is this, apart from the helmet manufacturers' and distributors'?
--
Michael MacClancy

 

[Scott]

"[Not Responding]" <[email protected]> wrote in message
news:<[email protected]>...

> All the evidence seems to be that the agenda is to increase voluntary helmet use to a point where
> compulsion can be brought in with relative ease.
>
> In this environment every time you wear a helmet you are making a vote, however unwillingly, for
> compulsory helmet laws.

Although I classify myself as pro-choice, and would never tell somebody they shouldn't wear a helmet
if they want to, in my heart of hearts I kinda feel this way, too.

I'd be genuinely bummed out by compulsion. It's a real quality-of-life issue for me. And I'm
speaking as somebody who's hit his head loads of times (most recently when walking into a lampost);
just never while cycling.

 

[Tony Raven]

Richard Burton <[email protected]> wrote:
>
> How can it be balanced when it ignores the largest piece of evidence, which coincidentally,
> doesn't support its preconceived ideas?
>

Can you give me a reference to that piece of work?

Tony

--
http://www.raven-family.com

"The reasonable man adapts himself to the world; the unreasonable man persists in trying to
adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George
Bernard Shaw

 

[Richard Burton]

Sorry Tony, but no I can't. There have been several reports about the fact that head injuries and
related deaths have not decreased pro rata, but only in line with the decrease in cycling that
helmet laws have brought about. Most were from Australia/NZ, but the last one was from the USA,
where heavy helmet promotion increased helmet-wearing, but had the perverse effect of increasing
deaths/injuries pro rata.

Do a search for cycle helmets and you'll find lots of stuff.

Rich

"Tony Raven" <[email protected]> wrote in message
news:[email protected]...
> Richard Burton <[email protected]> wrote:
> >
> > How can it be balanced when it ignores the largest piece of evidence, which coincidentally,
> > doesn't support its preconceived ideas?
> >
>
> Can you give me a reference to that piece of work?
>
> Tony
>
> --
> http://www.raven-family.com
>
> "The reasonable man adapts himself to the world; the unreasonable man persists in trying to
> adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George
> Bernard Shaw

 

[Tim Woodall]

On Mon, 21 Apr 2003 13:42:49 +0100, Richard Burton <[email protected]> wrote:

> "Tony Raven" <[email protected]> wrote in message
> news:[email protected]...
>> Richard Burton <[email protected]> wrote:
>> >
>> > How can it be balanced when it ignores the largest piece of evidence, which coincidentally,
>> > doesn't support its preconceived ideas?
>> >
>>
>> Can you give me a reference to that piece of work?
>>
> Sorry Tony, but no I can't. There have been several reports about the fact that head injuries and
> related deaths have not decreased pro rata, but only in line with the decrease in cycling that
> helmet laws have brought about. Most were from Australia/NZ, but the last one was from the USA,
> where heavy helmet promotion increased helmet-wearing, but had the perverse effect of increasing
> deaths/injuries pro rata.
>
> Do a search for cycle helmets and you'll find lots of stuff.
>

On the whole it seems reasonably balanced, until you get to the conclusions.

(1) There must be a high level of scientific evidence that bicycle helmets are effective in reducing
the rate of head injury to bicyclists.

and then

"The first of these criteria has been met."

This is probably the single most contentious point. The pro-choice lobby would argue that not only
do helmets have no measurable effect on the rate of head injuries but they actually increase the
risk of other injuries.

Regards,

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

http://tjw.hn.org/ http://www.locofungus.btinternet.co.uk/

 

[Tony Raven]

Tim Woodall <[email protected]> wrote:
>
> The pro-choice lobby would argue that not only do helmets have no measurable effect on the rate of
> head injuries but they actually increase the risk of other injuries.
>

I think you mean the anti-helmet lobby. The pro-choice lobby, of which I consider myself one, would
argue that it is up to each individual to weight the arguments and exercise their own personal
choice in whether or not to wear a helmet.

Tony

--
http://www.raven-family.com

"The reasonable man adapts himself to the world; the unreasonable man persists in trying to
adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George
Bernard Shaw

 

[Just Zis Guy]

On Sat, 19 Apr 2003 23:22:47 +0100, "Richard Burton" <[email protected]> wrote:

>I'm afraid I don't concur that it is balanced, and it appears to be yet another "scientific"
>analysis which ignores the fact that no whole population experience which shows that helmets are in
>any way effective.

I tend to agree - the people who wrote it fail to mention, as far as I've read so far, the
acknowledged fact that although most fatalities result from impact from a car, this kind of crash
falls outside the design parameters of bike helmets. The "research evidence" for protective effectis
mainly in single-vehicle accidents at speeds below 12mph, as far as my understanding goes.

Guy
===
** WARNING ** This posting may contain traces of irony. http://www.chapmancentral.com (BT ADSL and
dynamic DNS permitting)
NOTE: BT Openworld have now blocked port 25 (without notice), so old mail addresses may no longer
work. Apologies.

 

[Pete Jones]

On Mon, 21 Apr 2003 19:23:29 +0100, "Just zis Guy, you know?" <[email protected]> blathered:

>>I'm afraid I don't concur that it is balanced, and it appears to be yet another "scientific"
>>analysis which ignores the fact that no whole population experience which shows that helmets are
>>in any way effective.
>
>I tend to agree - the people who wrote it fail to mention, as far as I've read so far, the
>acknowledged fact that although most fatalities result from impact from a car, this kind of crash
>falls outside the design parameters of bike helmets. The "research evidence" for protective
>effectis mainly in single-vehicle accidents at speeds below 12mph, as far as my understanding goes.

Let's throw some more from the Favourites folder into the discussion - http://www.cycle-helmets.com/
http://www.magma.ca/~ocbc/ http://bmj.com/cgi/eletters/321/7268/1035 (interesting pros & cons if you
plough through that last collection; sample quote: "cyclists in countries such as The Netherlands
and Denmark, where helmets are rare, are safer than those in New Zealand and Australia, where
helmets have been mandated for years")

Pete
----
http://www.btinternet.com/~peteajones/

 

[Patrick Herring]

Tim Woodall <[email protected]> wrote: ...
| On the whole it seems reasonably balanced, until you get to the conclusions.
|
| (1) There must be a high level of scientific evidence that bicycle helmets are effective in
| reducing the rate of head injury to bicyclists.
|
| and then
|
| "The first of these criteria has been met."
|
| This is probably the single most contentious point.

I agree. The author appears to mean by (1) that helmets are provably effective in particular
individual cases, which is true as many here testify. Once you're flying through the air en route
for some hard stuff it's a good idea to put your helmet on. But there is another meaning to (1) i.e.
that the effect is generalisable over all the other factors causing accidents, which is precisely
the question at issue. It was bad authorship IMHO not to have made that clear.

yours, pro-choicably & anti-helmetarianly,

--
Patrick Herring, Sheffield, UK http://www.anweald.co.uk

 

[Tim Woodall]

On Mon, 21 Apr 2003 18:10:43 +0100, Tony Raven <[email protected]> wrote:
> Tim Woodall <[email protected]> wrote:
>>
>> The pro-choice lobby would argue that not only do helmets have no measurable effect on the rate
>> of head injuries but they actually increase the risk of other injuries.
>>
>
> I think you mean the anti-helmet lobby. The pro-choice lobby, of which I consider myself one,
> would argue that it is up to each individual to weight the arguments and exercise their own
> personal choice in whether or not to wear a helmet.
>
Indeed. However, it is disingenious of a report that claims to have a balanced look at the pros and
cons of helmet wearing to take the generally accepted view that, once a collision or accident has
occurred, a helmet will usually reduce the risk of head injury and then to ignore the other
evidence that suggests that _compulsory_[1] helmet wearing dramatically increases the risk of the
collision occuring.

From the figures for NSW and Victoria, my belief is that it is the compulsory wearing reducing total
cycling numbers, reducing the "visibility" of cyclists and in turn increasing the number of
cycle/motorvehicle collisions which are the accidents that tend to lead to head injuries (and lower
body injuries) that is what is swamping any possible benefit of helmets.

There may be some risk compensation occuring but I don't believe that that will be affecting the
head injury rate which tends to be as the result of car/cycle collisions where the extra 1mph or so
that someone might risk in a given situation is unlikely to make much difference to the collision
rate. OTOH, for single bike accidents that 1mph might make the difference between making it around a
"slippy" bend and losing it. (I don't believe that much more than 1mph can be involved because given
the same conditions, i.e. commuter, training, racing etc, then 1mph is likely to be all that is
physically and reasonably available - although top speed on decents might vary by a bit more. I very
nearly overcooked it on the windcheetah last week. 1mph may well have made all the difference
between "heart stopping exhilaration on two wheels" and sliding across the road on my side - and
possibly hitting my head - can I claim this as a serious head injury that didn't occur because I
wasn't wearing a helmet? ;-P )

Even motorcycle helmets appear to have a very small effect (if any) on fatal injury rates. It, of
course, depends on how you calculate the rate.

From http://www.bikersrights.com/statistics/goldstein/goldstein.html

If a major concern of policy makers is the prevention of fatalities, helmet legistlation may not be
effective in achieving that objective.

If the overall cost to society of motorcycle accidents is the issue, then cost-benefit analyses that
adequately consider the tradeoff between head and neck injuries must be conducted BEFORE the cost
effectiveness of helmets can be determined.

And a site to show that you can, relatively easily, "show" that compulsory bicycle helmets are an
extremely dangerous initiative: (see footnote [1] again)

http://agbu.une.edu.au/~drobinso/bhacc.htm

Finally, and unfortuately I can't find it again now, the fatality rates per 100,000 hours are
something like 50% HIGHER for car drivers and passengers than they are for cyclists (1998 figures
IIRC) If we could only convince people that they would be safer cycling to work instead of driving
then the increased cyclist number would probably make it safer still. (for my commute - 8 miles - it
takes me about 20% longer by bike than car on average although the s.d. for the bike is very small
(one snowy day excepted) while for the car it is a significant proportion of the mean) (My best ever
time for the car is just over 15 minutes (although that was motorway and is about 1/2 mile further
than the route I cycle) while my best time for the bike is about 20minutes (unfortuantely I didn't
time it but I started getting changed at work at 17:15 and I was in the house, at home, by 17:40)

Regards,

Tim.

[1] I use compulsory here because, as far as I can see the "voluntary helmet wearing" education
campaigns don't seem to have had the negative effects that the laws have. I would further
suggest that a NO helmet law (i.e. cycling helmets must NOT be worn) would similarly affect
cycling numbers and hence increase accident rates. However, I would suspect that had Australia
spent the umpteen million dollars on cyclist training and driver education instead of voluntary
helmet wearing education then they may well have seen significant health gains rather than the
general trend continuation they did see during those years.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

http://tjw.hn.org/ http://www.locofungus.btinternet.co.uk/

 

[Paul Smith]

On Tue, 22 Apr 2003 09:05:47 +0000 (UTC), Tim Woodall <[email protected]> wrote:

>There may be some risk compensation occuring but I don't believe that that will be affecting the
>head injury rate which tends to be as the result of car/cycle collisions where the extra 1mph or so
>that someone might risk in a given situation is unlikely to make much difference to the collision
>rate. OTOH, for single bike accidents that 1mph might make the difference between making it around
>a "slippy" bend and losing it. (I don't believe that much more than 1mph can be involved because
>given the same conditions, i.e. commuter, training, racing etc, then 1mph is likely to be all that
>is physically and reasonably available - although top speed on decents might vary by a bit more. I
>very nearly overcooked it on the windcheetah last week. 1mph may well have made all the difference
>between "heart stopping exhilaration on two wheels" and sliding across the road on my side - and
>possibly hitting my head - can I claim this as a serious head injury that didn't occur because I
>wasn't wearing a helmet? ;-P )

A rather more plausible risk compensation mechanism is that when perceived risk is lower less
attention is paid to the task at hand.

Since many accidents are avoided by a mechanism of early perception and planned avoidance, it
follows that less attention can easily lead to an increase in accidents.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Tony Raven]

Tim Woodall <[email protected]> wrote:
> On Mon, 21 Apr 2003 18:10:43 +0100,
>
> Indeed. However, it is disingenious of a report that claims to have a balanced look at the pros
> and cons of helmet wearing to take the generally accepted view that, once a collision or accident
> has occurred, a helmet will usually reduce the risk of head injury and then to ignore the other
> evidence that suggests that _compulsory_[1] helmet wearing dramatically increases the risk of the
> collision occuring.
>

Your reference [1] is the personal page of an beef cattle geneticist. It has not been peer reviewed
nor been published, nor are any publications on helmets listed in her publications list. Without
having checked every reference in the DfT report I believe it is based almost entirely on studies
that are published in peer reviewed literature. I do not see it being disingenous at all in ignoring
someone's personal web page in such a review.

Tony

--
http://www.raven-family.com

"The reasonable man adapts himself to the world; the unreasonable man persists in trying to
adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George
Bernard Shaw

 

[Tim Woodall]

On Tue, 22 Apr 2003 10:43:47 +0100, Tony Raven <[email protected]> wrote:
> Tim Woodall <[email protected]> wrote:
>> On Mon, 21 Apr 2003 18:10:43 +0100,
>>
>> Indeed. However, it is disingenious of a report that claims to have a balanced look at the pros
>> and cons of helmet wearing to take the generally accepted view that, once a collision or accident
>> has occurred, a helmet will usually reduce the risk of head injury and then to ignore the other
>> evidence that suggests that _compulsory_[1] helmet wearing dramatically increases the risk of the
>> collision occuring.
>>
>
> Your reference [1] is the personal page of an beef cattle geneticist. It has not been peer
> reviewed nor been published, nor are any publications on helmets listed in her publications list.
> Without having checked every reference in the DfT report I believe it is based almost entirely on
> studies that are published in peer reviewed literature. I do not see it being disingenous at all
> in ignoring someone's personal web page in such a review.
>
??? There wasn't a reference in [1]. I gave two URLs, one to show that even for motorcycle helmets
their efficacy is disputed and one to show that it is relatively trivial to analyse the Aus results
and get a negative benefit for legislation.

But this isn't the sole preserve of "beef cattle geneticists". Finch et al. 1993 Report No 45,
Monash University Accident Research Centre and Smith and Milthorpe 1993, Roads and Traffic
Authority both used matched before and after samples and both conclude that the primary effect of
helmet legislation has been a dramatic decrease in cycling while only a minimal decrease in head
injuries (2x decrease in cycling, 13% decrease in head injuries IIRC. The latest numbers I remember
seeing said head injuries are now higher than before legislation while cycling is still 15% down
but I may well have seen that in a newsgroup posting rather than a formal paper - I can't remember
where I saw it)

Scuffham, P.A., Langley, J. D., Trend in cycling injuries in New Zealand under voluntary helmet
use, 1997 analysed the trends in head injuries from 1980 to 1992 (I think - just before helmet
wearing became compulsory anyway) and found that the increase in voluntary helmet wearing during
this period has had little effect on the number of serious head injuries as a proportion of all
serious injuries.

Then there are papers like Robinson, B; or Robinson D.L.

And you don't have to mention the only paper that the anti-helmet lobby quotes: Hillman. The fact
that the paper that started this thread manages to dismiss Hillmans concerns is ridiculous (I don't
recall them mentioning any of the other papers - maybe their methodology is sufficiently flawed that
they can be ignored) but they do mention Hillman and so can't just assert that there is now
overwhelming scientific evidence that cycling helmets reduce the rate of head injuries but need, at
least, to argue why Hillman's claims are bogus.

I would like to get hold of a copy of Ulrich? paper where the four items in the conclusion that are
listed come from . I would be interested to see how (s)he defines "risk of head injury".

And yes, all the statistics might be bogus: Cameron, Heiman and Neiger 1992 state it is "almost
impossible to isolate and measure the contribution of cycle helmets", and that "there are no
reliable figures on which to base analysis" but, to me at least, if the benefits of helmets were as
good as many claim then I don't believe people would be able to dispute the benefits using what
looks to me as reasonable analysis of the results in Aus, NZ and Canada.

I supose the one (hopefully indisputable) good thing out of all of this legislation, nobody disputes
that helmet wearing increased significantly post legislation, even in NZ where the rates were
already very high. Cyclists are obviously a law abiding folk.

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

http://tjw.hn.org/ http://www.locofungus.btinternet.co.uk/

 

[Tony Raven]

Tim Woodall <[email protected]> wrote:
>>
> ??? There wasn't a reference in [1].

In which case I apologise for misreading your post.

Tony

--
http://www.raven-family.com

"The reasonable man adapts himself to the world; the unreasonable man persists in trying to
adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George
Bernard Shaw

 

[David Damerell]

Patrick Herring <[email protected]> wrote:
>I agree. The author appears to mean by (1) that helmets are provably effective in particular
>individual cases, which is true as many here testify. Once you're flying through the air en route
>for some hard stuff it's a good idea to put your helmet on.

This is by no means proven; it seems likely that helmets have little effect on severe impacts, and
exacerbate torsional injuries.

"many here testify" - in fact, the sheer number of "helmet saved me" anecdotes illustrates that that
assessment cannot be correct in the majority of cases.
--
David Damerell <[email protected]> Distortion Field!

 

[Tim Woodall]

On Tue, 22 Apr 2003 13:23:24 +0100, Tony Raven <[email protected]> wrote:
> Tim Woodall <[email protected]> wrote:
>>>
>> ??? There wasn't a reference in [1].
>
> In which case I apologise for misreading your post.
>
>
That's OK. I reread my posting twice to try and see what confusion I had caused and it all seemed
clear to me but obviously wasn't sufficiently unambigious.

I think it was you who said the (original) paper seemed well balanced, and I would agree. Except for
the one statement that has kicked off this sub-thread. (I haven't read the paper very carefully so
there may be other things I disagree with but this claim was the only one that made me stop and
reread to make sure I understood why they were claiming it)

Regards,

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

http://tjw.hn.org/ http://www.locofungus.btinternet.co.uk/

 

[Tim Woodall]

On 22 Apr 2003 15:40:18 +0100 (BST), David Damerell <[email protected]> wrote:
> Patrick Herring <[email protected]> wrote:
>>I agree. The author appears to mean by (1) that helmets are provably effective in particular
>>individual cases, which is true as many here testify. Once you're flying through the air en route
>>for some hard stuff it's a good idea to put your helmet on.
>
> This is by no means proven; it seems likely that helmets have little effect on severe impacts, and
> exacerbate torsional injuries.
>
> "many here testify" - in fact, the sheer number of "helmet saved me" anecdotes illustrates that
> that assessment cannot be correct in the majority of cases.

Not necessarily. The helmet saved me cases could all be true and evidence of a dramatic risk
compensation "attitude" amongst cyclists. (Personally I don't believe it but it could be true)

This could also then be used to explain the Aus results. Those who wore helmets before are still
cycling, those who didn't have stopped cycling. The helmet wearers were the ones having all the
accidents and so there has been a negligible drop in accidents despite a halving of cycling. (Again,
I don't believe it!)

There are other possible explanations I can think of as well but given that this is an emotional
subject already I think it is probably foolish to pour oil on the flames ;-)

Regards,

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

http://tjw.hn.org/ http://www.locofungus.btinternet.co.uk/

 

[David Damerell]

Tim Woodall <[email protected]> wrote:
>David Damerell <[email protected]> wrote:
>>"many here testify" - in fact, the sheer number of "helmet saved me" anecdotes illustrates that
>>that assessment cannot be correct in the majority of cases.
>Not necessarily. The helmet saved me cases could all be true and evidence of a dramatic risk
>compensation "attitude" amongst cyclists.

We do this every time. Yes, it is also possible that helmets make one grossly accident-prone, but
equally that is not an argument for wearing one.
--
David Damerell <[email protected]> Distortion Field!

 

[Patrick Herring]

David Damerell <[email protected]> wrote:

| Patrick Herring <[email protected]> wrote:
| >I agree. The author appears to mean by (1) that helmets are provably effective in particular
| >individual cases, which is true as many here testify. Once you're flying through the air en route
| >for some hard stuff it's a good idea to put your helmet on.
|
| This is by no means proven; it seems likely that helmets have little effect on severe impacts, and
| exacerbate torsional injuries.

Yes, actually I agree with that but forgot when posting.

--
Patrick Herring, Sheffield, UK http://www.anweald.co.uk

 

[Tony Raven]

David Damerell <[email protected]> wrote:
>
> it seems likely that helmets have little effect on severe impacts.
>

Not necessarily so. Since 1993 they have had black boxes on Indy cars gathering data when accidents
happen. Its been found that the human body can withstand decelerations up to 130G - much more than
previously thought. A major safety increase was achieved by putting crash attenuators on the back of
the car - basically a 6" crushable aluminium honeycomb can. The slight reduction in deceleration
resulting from the crushing 6" of honeycomb in a 200mph rear end into wall crash was sufficient to
improve survivability significantly. In that light an inch of foam could make a difference at speeds
and decelerations well outside those set in the various testing standards.

Tony

-- http://www.raven-family.com

"The reasonable man adapts himself to the world; the unreasonable man persists in trying to
adapt the world to himself. Therefore, all progress depends on the unreasonable man." -- George
Bernard Shaw