"Ian" <
[email protected]> wrote in message
news:BBD94571.16D79%[email protected]...
> > Call it a foible. I can't allow advocacy of compulsory helmets pass unchallenged, because the
> > only research that has ever suggested
significant
> > benefit from wearing a helmet has been from people who have already made
up
> > their minds that they want helmets to be compulsory, and no country
which
> > has tried it has actually reduced injury rates. Cycling rates, yes,
helmet
> > laws cut cycling rates pretty dramatically, but injury rates remain the same. Until we know why
> > I am unwilling for me or my children to be lab
rats
> > in the same failed experiment.
> So all the development that helmet manufacturers put into helmets is not worth a light?
It would seem so, judging by the published figures.
> Can you tell me what the vast majority of cycle injuries are?
The vast majority of cycle injuries are: irrelevant to this discussion. Liddites claim that lids
reduce head injuries by 85%; countries introduce compulsory helmet legislation as a result; those
countries experience no measurable reduction in head injury rates. That means one of two things:
either the helmets do not work, or they work just fine but they make a crash more likely to happen,
thus cancelling out their effect. I don't know which, and nobody seems to be working on finding out.
Until we know what's going on, I am vehemently opposed to compulsory helmet laws.
The TRL produced a report suggesting that injury rates increased in areas where there was aggressive
helmet promotion. Does this explain the observed facts? Who knows? I wrote to the DfT asking them,
and they sent me a form letter by reply which failed to acknowledge that the issue even existed. But
it does exist, because John Franklin (who knows more about cycling than am ever likely to) says it
exists. And so do lots of other people.
We are not anti-helmet, we are anti-compulsion. And we are not anti-compulsion because we don't
believe helmets work, we are anti-compulsion because logic indicates that they should work, but
whole population and time-series data repeatedly prove that at the populaiton level they don't. So
there is a gap between the specific effect of a helmet in a crash and the actual effect of helmets
in populations. Maybe helmeted cyclists ride more dangerously, or maybe the kinds of crashes wich
account for hospital admissions (notably those involving motor vehicles) are, as the helmet
manufacturers acknowledge, beyond the capabilities of helmets.
> We are not talking about the blanket of all injuries here afterall, just head injuries, you
> trotting out non specifics and swallowing wholesale non specifics from elsewhere is showing you to
> have "ostrich" syndrome.
Yes, head injuries not blanket injuries. So how come the leading study quoted by helmet advocates
also manages to show that helmets reduce leg and torso injuries? It cuts both ways, you see. The
simple fact is that head injury rates have not fallen where helmet use has risen. The ratio of
cyclist to pedestrian injuries is static over time despite increasing use of helmets. This is tru
for children as well as adults.
I can model something on a small scale and persuade myself it works, maybe like the perpetual motion
machines they sold as desk toys in the 70s, but if I test my hypothesis on whole population and
time-series data, occasionally causing large step changes in usage rates, and the results
persistently show no measurable effect (which they do), then my model is clearly flawed. You can
take a wide range of data from Australia and New Zealand, and other places, and say "point to the
place where the helmet law was introduced" and it's impossible.
> Lets look at New Zealand
Yes, let's. Taking the original data, Dr Nigel Perry graphed the change in the ratio of head
injuries to all injuries, relative to a reference date, March 1988. He co-plotted for two groups:
cyclists, and a control group of the whole population - motorists, pedestrians, ladder climbers -
everyone who sustained an injury. If helmets prevent 85% of head injuries this will be clearly
visible in this graph.
This graph shows that:
- The general fall in the likelihood of head injury for cyclists coincides to a high degree with a
similar fall in head injury for non-cyclists (who make up the great majority of the whole
population control group).
- There is a fall for cyclists and not the control group when the law was introduced, but the
cyclist head injury rate had previously risen above the overall one, and the fall is soon followed
by an increase. The cyclist head injury rate does appear to fluctuate a little more than the
overall rate.
- There has been no additional benefit for cyclists through the wearing of helmets that has not been
enjoyed by the population as a whole without helmets. This is despite the fact that the survey on
which the graph is based included head injuries sustained in simple falls (for which cycle helmets
are designed to offer some degree of protection) as well as more serious instances of collisions
with motor vehicles.
http://www.cyclehelmets.org/papers/c2007.pdf
> Australia.
Cameron et al (1994) fitted a logistic regression to the pre-law data and extrapolated it beyond the
helmet law introduction. Post-law, the only significant change from the regression line was the
1992/93 point which lies below their 95% confidence limits. It is likely that changes in reporting
rates, hospital procedures or some other factor can account for this discrepancy in an otherwise
relatively smooth trend.
Charting the percentage of head injuries amongst hospitalised cyclists [...] It is not possible to
discern from the graph the year of introduction of the legislation.
http://www.cyclehelmets.org/papers/c2016.pdf
> Of course this isn't worth anything to you because you would rather we
have
> a head injury and a broken leg rather than just the leg, so you can say
that
> we need to educate car drivers, a few more brain damaged kids will help further your cause
> afterall.
It is not worth anything to me because the reports you quote were commissioned by the respective
Governments in order to "prove" that they were right to introduce helmet legislation, as a response
to comments in the learned journals which pointed out that despiote a large step-change in wearing
rates there was no discernible corresponding change in injury rates. The trend in cyclist head
injury vs. all injury rates is essentially flat over time.
> "Bicyclists admitted to hospital with head injuries are 20 times as likely to die as those
> without."
Quite possibly, but there is no evidence that helmets have any impact on this. There is no
credible evidence to suggest that, in a given impact, a helmet will make the difference between
life and death.
> Of course non of this research exists according to you.
Oh it exists all right, as I said above. And there is a similarly large body of research pointing
out that, despite these grandiose claims, the effect of cycle helmets in overall casualty trends is
invisibly small. Except in British Columbia, where head injury rates have increased significantly
post-law. Oops.
> How about this non scientific test.
http://www.sph.emory.edu/Helmets/HRC/boardman.html
Non-scientific,as you say. At least two helmeted riders died in the USA last year, and a large
number of unhelmeted riders have survived. And we could use similar graphic pictures of motor racing
crashes to show that all car drivers should wear Nomex suits and full-face helmets. This is just
shroud-waving and it sheds more heat than light. Think of Nikki Lauda! Don't go out without your
fireproof longjohns!
The human skull is tough. My friend Albert, in his seventies, did a header over the bars while not
wearing a helmet and suffered nothing worse than cuts. I don't want the cuts - so I wear a plastic
hat - but the skull saved his life. Scope for a "skull saved my life" thread maybe? We are all
fitted with a skull as standard.
> "However, the great majority of the fatalities and approximately half the injuries - most of them
> to adults - result from damage to the head
following
> collision with a car or goods vehicle."
Now check the disclaimer on your helmet. You will find that any collision with a motor vehicle is
outside the design parameters of a cycle helmet. No helmet is designed to withstand impacts of that
severity. The various tests are designed to mimic the effect of a fall from a bicicyle to the ground
at low speeds, usually quoted at not more than 12mph.
> How much research do you want?
Anything credible based on whole population or time-series data will do. Well, there would probably
have to be a couple of reports, to balance the large stack which prove no effect.
> So come on, lose the blanket you hide behind and talk "head injuries".
I have no problem talking about head injuries, injuries, non-head injuries. The fact remains that
the effect of helmets on injury rates including or excluding head injuries is unmeasurably small
when applied to whole populations.
> Of course I'm sure no studies are valid unless you do them yourself with your huge knowledge of
> such matters[SARCASM]
I make no claims to expertise - but here are some people who do:
http://www.cyclehelmets.org. Helmet
advocates make substantial claims, 85% of head injuries prevented being one common one. BHIT quoted
exactly this figure in the Early Day Motion they sponsored. That figure is no longer supported by
its authors, who have published corrections over time. BHIT still use the incorrect figure. Even
taking the lower figures of around 60%, if you double the helmet wearing rate you would expect to
see a large change in the ratio of head injuries to all injuries. In Australia this change is
vivible only in the non-cycling population, not the cycling population. Why? I don't claim to know.
But I do suggest that until the gulf between the claims and the reality is fully understood, to
advocate helmet compuslion is irresponsible.
TRL apparnetly claim around 16% injury reductions. That at least is credible. Looking for a number
that small in the overall data would demand different techniques which I don't think Franklin et.
al. have tried yet, but then I've not seen the TRL report which claimed 16% - it might someone
misremembering.
> Not trying to pick a fight, just trying to open some eyes, and I still advocate choice on wearing
> helmets in adults.
But you're not opening my eyes in saying these things, Ian, because I have already read those
reports. I was originally a Liddite. It was only through reading the research that I arrived at my
current position, and that was at least inpart due to comparing the strident tone of the "pro"
reports with the much more measured approach by some of the sceptics. Even the BMA does not think
helmet compulsion is a good idea.
And confining it to children is a fig-leaf, a piece of BHIT dishonesty hoping to get legislation in
and then extend it in future, when the adult wearing rate is higher because of all those kids who've
got into the habit of wearing a lid.
90% of child cycling accidents happen off the roads. How would legislation mandating helmet use for
children on the road affect this? BHIT know that perfectly well.
But it would have given the insurers of the driver who hit Darren Coombs a way of claiming that his
injuries were his own fault. It is pointless to deny that insurers would use such legislation in the
courts, because they already try to claim contributory negligence when cyclists are hit by car
drivers and suffer head injuries while not wearing helmets.
--
Guy
===
WARNING: may contain traces of irony. Contents may settle after posting.
http://chapmancentral.demon.co.uk
