Another doctor questions helmet research

"Chris BeHanna" wrote in message
newsan.2004.08.13.16.47.16.256376@allspammersmus tdie.behanna.org...

I have asked a question that has not yet been answered: In the
universe of accident-involved bicyclists who have head injuries, are
helmet-wearing bicyclists underrepresented?

And that's been answer many times in the various studies that are available
to you should you prefer to look them up. But the short answer is NO,
helmets appear to have no effect on the presence or absense of serious or
fatal injuries.

Furthermore, there is no strong data that shows that many bicyclists get
serious head injuries. Certainly what is shown by the statistics is that
less than 2% of all vehicular head injuries are attributable to bicyclists.

When I have that answer, I'll be content.

I rather doubt that. You show a great deal of the pro-helmet crowd which
believes in the magic of 1" of foamed plastic vs a 30 mph motor vehicle.

Alas, it is not so. I have seen more than one post that claims
that helmets are worthless, or that claims "I fell and hit my head and
I'm still here; ergo, helmets are worthless."

However, there were claim after claim after claim for Skid Lids written by
people who claimed that their lives were saved by that helmet when they
fell. That helmet had no padding and couldn't pass the simplest test that
the Snell Memorial Institute could devise. This demonstrates that claims of
the effectiveness of safety equipment of any kind must be taken with a heavy
dose of salt.

I particularly remember coming out onto the front straight at Vaca Valley
Raceway on my Kawasaki factory road racer and having it sieze up and dump me
rather unceremoniously onto the ground. While sliding down the road at a
high rate of speed I was holding my head up and trying to see where I was
sliding. Since I was going directly down the road I decided that I was safe
and could put my head down protected by the helmet. If I hadn't been wearing
that helmet I wouldn't have put my head down. And that in a nutshell is why
a lot of people can point to damaged helmets and say, "See, it saved me a
lot of damage." If you aren't wearing a helmet you think about your head
first.

Now, certainly you can theorize that there are accidents in which you don't
have time to worry about your head. I'm sure there are - the same sort of
accidents which are so violent that a helmet makes essentially no
difference.

And of course NONE of this is helped by the fact that pro-helmeteers are
willing to lie, distort or to simply quote long disproved studies.

Case in point: February Fitness Magazine. While sitting in the blood lab
waiting to bleed into a test tube I picked that rag up and flipped through
it. The second page I stopped on had the headline size print: "Bicycle
helmets prevent 88% of all serious and fatal injuries." Bell Sport.

Now that 88% number came from the original Thompson, Rivara and Thompson
study in Seattle. They had a poorly designed study that used a very small
number of upper class bicyclists who wore helmets and compared them against
a larger number of lower income bicycle riders. If memory serves there
wasn't a single fatality or serious head injury in the statistics and the
statistics showed something like 74% fewer minor injuries by bicyclists
wearing helmets. But, the assumed that if they had done their statistical
evaluation in another manner it might provide a number LIKE 88%.

This "study" was in all of the headlines everywhere and soon another "study"
used the TRT study for it's numbers but they obviously didn't actually read
it because they CLAIMED that helmets would prevent 85% of ALL SERIOUS OR
FATAL HEAD INJURIES! Something that even the amazingly biased TRT study
never claimed.

So, NOW we see that Bell Sports (who, btw, happened to fund the TRT study)
is spreading these bogus numbers around two decades after they were disputed
and despite the fact that full population studies have failed to find a
detectable difference between helmeted and unhelmeted riders.

Chris BeHanna wrote:

On Fri, 13 Aug 2004 20:42:29 +0100, Just zis Guy, you know? wrote:


On Fri, 13 Aug 2004 16:37:17 GMT, Chris BeHanna
wrote in message
pan.2004.08.13.16.47.16.256376@allspammersmustd ie.behanna.org:


I have asked a question that has not yet been answered: In the
universe of accident-involved bicyclists who have head injuries, are
helmet-wearing bicyclists underrepresented?

Assuming you are not concerned about trivial injuries, then no.


Cite?

The citation I like best is "Trends in Cycle Injury in New Zealand under
Voluntary Helmet Use", Scuffham, P. et. al, Accident Analyis &
Prevention, vol 29, no 1 pp 1-9, 1997.

Scuffham worked for the NZ government's Injury Prevention Research Unit
then. The "voluntary helmet use" referred to the time from 1980 to
1993. From 1990 on, prior to making helmets mandatory for all ages, the
NZ government promoted their use heavily, and helmet wearing went from
zero up to the mid-1980s, to about 20% in 1989, then suddenly shot up to
about 90% for kids, about 70% for teens and about 45% for adults.

Scuffham figured this was a great test of helmets. He wanted to display
the drop in head injuries. But because of previous bad studies of
similar events in Australia, he was smart enough not to just look at the
_count_ of HI. (In Oz, cycling dropped sharply when helmets were
mandated. Helmet proponents trumpeted a drop in HI, but were
discredited when others pointed out the drop in cycling was _greater_ -
meanign more HI per remaining cyclist.)

So Scuffham & team looked at records of all hospitalized cyclists since
1980, and computed _percentages_. To go with the sudden rise in helmet
use for the three age groups studied, he wanted to show the sudden drop
in the _percentage_ hospitalized due to HI (as opposed to broken bones,
etc.)

There are nice graphs in the paper for the three age groups. They show
the percentage hospitalized due to HI dropping slowly and steadily since
1980 - perhaps because doctors got better at diagnosing & treating these
things. (The same drop exists for pedestrians, BTW.) There's some
obvious random variation, but there is NO change in the gentle downward
slope due to the sudden surge in helmet use.

In papers of this type, they don't just visually inspect graphs, of
course; they apply pretty sophisticated math to examine the effect of
lots of different variables. But no matter. The only significant
variable was "time" - the later the year, the smaller the percentage
with HI. In particular, no matter how they sliced it mathematically,
the use of helmets made no detectable difference. To quote: "What is
clear from our findings ... is that cycle helmets are not achieving the
gains which were expected of them."

Now it's interesting that a few years later, Scuffham "reexamined" his
data; and in the mathematics, he purposely left out the "time" variable.
And presto, he found that helmets reduced HI by 19%. But other
researchers have re-processed his data including the very obvious "time"
variable and found that, as before, the helmet benefit goes away.


I like Scuffham's methods for many reasons. Compared to, say, Thompson
& Rivara or other case-control studies (T&R are the source of the
magical "85% reduction"), Scuffham's methods are much less biased by
self-selection of subjects - that is, by wealthier white kids in helmets
being taken into the ER "just in case" because their insurance will
cover it anyway, verus poor unhelmeted kids taken in only if the injury
is truly bad. Scuffham's sample size is much, much larger too, and his
"percentage" technique neatly avoids treating reduced cycling as a benefit.

I'll also mention that even if his later "19%" paper were accurate, I'd
treat that as much more plausible than the usual "85%" garbage. But
having read the papers and the resulting discussions, I'm convinced the
second paper is not accurate. Scuffham first effort got lots of grief
from the pro-helmet crowd, I'm told. (I read an account from a fellow
presenter at the first conference where he presented his paper.) I
wonder if he also got grief from his employers. In any case, purposely
removing the variable shown to be most significant is odd in the extreme!

Now, does this (or similar data) mean helmets are absolutely useless?
Well, no - it probably means they actually protect against only what
they're certified for: a stationary topple of a person seated on a bike.
But of course, stationary topples and prevention of scratches &
bruises isn't what sells helmets, or helmet laws for that matter.
They're touted as preventing truly serious injuries, including deaths.

At that, I'm convinced, they don't work.

--
--------------------+
Frank Krygowski [To reply, remove rodent and vegetable dot com,
replace with cc.ysu dot edu]

Chris BeHanna Wrote:

I have asked a question that has not yet been answered: In the
universe of accident-involved bicyclists who have head injuries, are
helmet-wearing bicyclists underrepresented?

When I have that answer, I'll be content.


I can point you to the research of UK's Mayer Hillman, Ozzie's Dorothy
Robinson - both of whom also refer to US's Rogers who found helmeted
riders to be over represented in the HI stakes.
I can't be bothered expending much effort in order to help you in your
quest for contentedness - you'll need to use some of your own
initiative here.

As the old (pre PC days) saying goes "who was your last little black
boy?"

Roger


--
RogerDodger

Chris BeHanna Wrote:


Both motorcycle helmets and bicycle helmets have limitations in
what they can do for the wearer. Neither should be mandated by
nanny
government. Somehow, the anti-mandate crowd focusses on attacking
the device rather than the mandate.

The logic here seems extra-planetory, or in need of further
explaining.
The fact that the anti-mandate focusses on challenging the claimed
efficacy of the device, effectively is an attack on the mandate because
the mandate's foundation, it's warrant, is the necessity that the
device be efficacious. If the efficacy is found to be illusiory - like
the belief that the starry heavens revolve around the earth - if the
warrant underpinning the mandate is found to be erroneous, the mandate
collapses (like classical physics and Bohr's hydrogen model).

Chris, your thinking here seems convoluted.

Roger


--
RogerDodger

Chris BeHanna Wrote:
[Guy wrote:] Assuming you are not concerned about trivial injuries,
then no.

[Chris responds:] Cite?

Seems to be a common ploy that some people with an overweening sense of
self importance tack on "Cite" a lot as if their viewpoint is on higher
ground and the onus is on us to run around after them providing
substantive support for our contentions. Compare that with the
uncritical claptrap that the other side has propagated with impunity.

Toss that!

One standard for both sides is what I say.

This tendency for this lot to demand citations just shows their pompous
and hypocritical conceit, in my view.

Roger


--
RogerDodger

Frank Krygowski Wrote:


The citation I like best is "Trends in Cycle Injury in New Zealand
under
Voluntary Helmet Use", Scuffham, P. et. al, Accident Analyis &
Prevention, vol 29, no 1 pp 1-9, 1997.

Scuffham worked for the NZ government's Injury Prevention Research
Unit
then. Frank Krygowski [To reply, remove rodent and vegetable dot
com,
replace with cc.ysu dot edu]

Sorry Frank but just two minor errors he
(1) research by Scuffham and head of the IPRU Prof. John Langley.
(2) IPRU is an offshoot of Otago University and is funded, according to
the acknowledgements in the 1997 AAP paper (above), as funded by two
government funded organisations - the Accident Compensation Corporation
and the Health Research Council.

Roger


--
RogerDodger

Just zis Guy, you know? Wrote:
Michael Warner wrote:

ISTM that non-helmet-wearers see entire nations of
compulsory-helmet-wearers as a threat to their civil liberties.

I don't. I see them as poster children for why compulsion is bad.
Look at
Australia, for example; in Syndey the number of teenage girsl who
cycled
after the law was 90% down on the figure pre-law - and teenaged girls
are
already one of the groups least likely to cycle.

Guy
--


Gedanken - thought experiment - imagine what would happen if people
started getting indignant and moralistically militant demanding helmets
for car occupants (and imagine at the same time there was a complete
absence of any MHL's for cyclists and not even a whisper that cyclists
should wear them).

Can you imagine the outcry against car helmets, and perhaps it would
lead to a decrease in car driving because people (mainly girls and
women) don't want their coiffures ruffled. Yes I can envisage what
would happen - a downsurge in car driving and an upsurge in cycling
where there's no coiffure interruptus.

Roger


--
RogerDodger

On Sat, 14 Aug 2004 14:10:35 +1000, RogerDodger
wrote:


Frank Krygowski Wrote:


The citation I like best is "Trends in Cycle Injury in New Zealand
under
Voluntary Helmet Use", Scuffham, P. et. al, Accident Analyis &
Prevention, vol 29, no 1 pp 1-9, 1997.

Scuffham worked for the NZ government's Injury Prevention Research
Unit
then. Frank Krygowski [To reply, remove rodent and vegetable dot
com,
replace with cc.ysu dot edu]

Sorry Frank but just two minor errors he
(1) research by Scuffham and head of the IPRU Prof. John Langley.
(2) IPRU is an offshoot of Otago University and is funded, according to
the acknowledgements in the 1997 AAP paper (above), as funded by two
government funded organisations - the Accident Compensation Corporation
and the Health Research Council.

Fill me in on the implications. A naive outsider would assume that
both constituent organizations of the IPRU would be helmet-use
boosters...right?

If so, what does it mean if their own study is less than conclusive on
the ultimate benefit of compulsory helmet use?

-Luigi



Roger

Luigi de Guzman Wrote:


Fill me in on the implications. A naive outsider would assume that
both constituent organizations of the IPRU would be helmet-use
boosters...right?

If so, what does it mean if their own study is less than conclusive on
the ultimate benefit of compulsory helmet use?

-Luigi


QUOTE]

The imperatives if both these organisations (or more correctly a
corporation and council) would, one could reasonably confidently
expect, have for the investigations in pursuit of measures and means of
reductions of accidents and the ensueing and ongoing costs thereof. In
the case of the Health Research Council $ might not figure as much as
with ACC for which the budget burden (tax funded) is considerable. The
prime objectives of each are slightly different but prevention is
central.


--
RogerDodger

Luigi de Guzman Wrote:


Fill me in on the implications. A naive outsider would assume that
both constituent organizations of the IPRU would be helmet-use
boosters...right?

If so, what does it mean if their own study is less than conclusive on
the ultimate benefit of compulsory helmet use?

-Luigi


/
I didn't answer the second question but I would point to the idea
encapsulated in "escalation of commitment".

Human nature - belief perserverance, confirmation bias, unwillingness
to alter views from the first one - its all documented in psychology
and incredibly Sir Francis Bacon was seminal in this in Novum Organum
(~1520, the time of Shakespeare):

XLVI
The human understanding when it has once adopted an opinion (either as
being the received opinion or as being agreeable to itself) draws all
things else to support and agree with it. And though there be a greater
number and weight of instances to be found on the other side, yet these
it either neglects and despises, or else by some distinction sets aside
and rejects, in order that by this great and pernicious predetermination
the authority of its former conclusions may remain inviolate. And
therefore it was a good answer that was made by one who, when they
showed him hanging in a temple a picture of those who had paid their
vows as having escaped shipwreck, and would have him say whether he did
not now acknowledge the power of the gods — "Aye," asked he again, "but
where are they painted that were drowned after their vows?" And such is
the way of all superstition, whether in astrology, dreams, omens, divine
judgments, or the like; wherein men, having a delight in such vanities,
mark the events where they are fulfilled, but where they fail, though
this happen much oftener, neglect and pass them by. But with far more
subtlety does this mischief insinuate itself into philosophy and the
sciences; in which the first conclusion colors and brings into
conformity with itself all that come after, though far sounder and
better. Besides, independently of that delight and vanity which I have
described, it is the peculiar and perpetual error of the human
intellect to be more moved and excited by affirmatives than by
negatives; whereas it ought properly to hold itself indifferently
disposed toward both alike. Indeed, in the establishment of any true
axiom, the negative instance is the more forcible of the two.


--
RogerDodger