Another doctor questions helmet research

Chris BeHanna wrote:

On Fri, 13 Aug 2004 22:17:13 -0400, Frank Krygowski wrote:

.... To quote: "What is
clear from our findings ... is that cycle helmets are not achieving the
gains which were expected of them."

[...snip...]


Very interesting. Now, I wonder, did Scuffham go further and look
at whether or not the patients admitted with head injuries were or
weren't wearing helmets at the time of their accidents? The answer to
the question that I have been asking could easily be answered if he
did.

He did not, AFAIK, because there was no mechanism for checking this, I
think. However, understand that for one age group (kids younger than
teens) the percentage in helmets at the end was over 90%. It's simply
not plausible that _all_ of those hospitalized due to head injuries came
from the last 10% to take up helmets, and that going all the way back to
1980, some equivalent population was responsible for all hospitalizable
head injuries.

Come to think of it, if that _were_ the case, it makes absolutely no
sense to even sell helmets! Those who would buy them under any
circumstances must be the ones who would never need them; and those who
absolutely refuse their use are the only ones who would ever benefit!

That's too absurd to be taken seriously, compared to the alternative
explanation: that the helmets had no effect on serious (i.e.
hospitalizable) head injuries.



I've been googling, and unfortunately, I'm having some trouble
finding the text of the study.

Accident Analysis & Prevention is available online only if you're
connected with a library system that pays the hefty subscription fee.
I'm lucky enough to be so connected. But generally, other libraries can
get such articles for a fee. I'd recommend doing so.


What I have found thus far has not been terribly encouraging:

http://www.zzapp.org/rileygea/itsa/helmet2.htm

This page presents a credible argument that FARS helmet use data for
accident-involved bicyclists in the U.S. is unreliable, which makes it
much, much harder to answer my question.

Riley is _very_ knowledgeable in this area. He's able to see
implications in the raw data that would forever elude me.

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.


Stationary or in motion, the closing speed of the cyclist's head
with the ground is the same, and, IMHO, the benefit provided by the
helmet in reducing the impulse delivered to the cyclist's head
FROM THE GROUND is the same. Of course, injuries from collisions
with fenceposts, automobiles, or other stationary objects for which
the horizontal component of the cyclist's velocity is greater than
that for which the helmet was designed to mitigate will not be
affected by the presence or absence of a helmet.

As a person who teaches courses in classical mechanics, I understand the
logic, but I'm not convinced that simple analysis applies.

Obviously, there are circumstances we all recognize where a vehicle can
directly impact a cyclist's head at well over the "certified" speed.
(Actually, _we_ recognize that, but others don't; during a failed
attempt at a MHL in my state, a pro-MHL article that appeared in many
newspapers claimed a 14 year old would have survived his head-on
collision with a 35 mph Chevy Blazer if only he'd worn a helmet. The
kid was riding facing traffic, BTW.)

But beyond that, I think many impacts that are not directly to the head
can cause greater impact speeds. As an example: balance a pencil on
point, and impact it 1/4 of its height above the table. The eraser hits
at a higher speed than in a slow topple. I think similar things can
happen when a cyclist is struck, although the physics is chaotic enough
to defy ordinary analysis.


The best that can be said for either side, I think, is that the
data to answer the question regarding whether or not bicycle helmets
are effective at reducing or preventing serious head injuries is still
open. Certainly, helmet *LAWS* are ineffective, and I DO NOT SUPPORT
THEM.

Obviously I disagree with the "still open" idea, because of the observed
effects of helmet laws. Not all helmet laws, but the strictly enforced,
nationwide, all-ages laws in New Zealand and Australia. When you get
90% or more of those country's populations to suddenly use helmets all
the time, and when the serious head injuries per rider do not fall, it
seems difficult to pretend the helmets are somehow effective!



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

Chris BeHanna Wrote:
On Sat, 14 Aug 2004 13:38:42 +1000, RogerDodger wrote:


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'
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 i
your
quest for contentedness - you'll need to use some of your own
initiative here.

How nice of you. The title of the paper or even the year of
publication wouldn't be too much to ask, would it? Google is a very
big place.


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

That is truly offensive, and only cements the view of you that
I've formed by reading other posts of yours.

--
Chris BeHanna


Yes Chris I concede that I have displayed a rather and perhap
unjustified and unnecesarily impolite and abrasive approach to some o
your posts - I apologise but not unreservedly as I am very reluctant t
run around doing legwork for people who are perhaps not genuinel
interested in giving a fair hearing to opposing evidence an
argument.

Here is some info that might be helpful:

Email from Dorothy Robinson (Australian Researcher/ Biostaticia
permission hasn't been asked or given to reproduce this but I a
hopeful that Dorre will not object)

To
Sent Monday 15 September 2003

2) Empirical studies suggest that helmet wearers hit their heads mor
often than non-wearers. This again may be due to the greater size an
mass of the head - a skid where a non-helmeted head just misses th
ground by half an inch will cause a helmeted head to impact th
pavement. Some people have also argued that weight of the helme
affects balance, especially going over rough surfaces such as bumps o
pot-holes. These arguments have been expounded in an article, 'Bicycl
helmets and accident involvement' , published in Cycling World, a U
magazine.

Below is some further information. The arguments are plausible, and i
would seem reasonable not to want to wear a bike helmet if, havin
weighed up the evidence, you thought that helmets were likely t
increase the risk of hitting your head and suffering rotationa
injuries including shearing connections between neurones and consequen
loss of brain function.


Evidence for Increased Head Hitting Rates Amongst Helmet Wearers
The extra size of a helmeted head seems to result in helmet wearer
hitting their heads more often than non wearers. Evidence for thi
comes from three published papers which looked at head hitting rates.
In each case, helmet wearing amongst cyclists who had hit their head
was extraordinarily high.

Dorsh et al. (Acc Anal Prev, 19: 183-190), sent out questionnaire
(c 1982) to various bicycle clubs in Adelaide, requesting informatio
about head injuries and head hitting rates. 23% of respondents had hi
their heads. 62% of them were wearing helmets at the time! Given th
year and what is generally known about helmet wearing in that period
this proportion is quite astonishing. I wrote to the author, but sh
failed to provide any information about helmet wearing in the sampl
who didn't hit their heads.

Another paper from the US (Wasserman et al. 1988, Amer J Publi
Health, 78: 1220-1221) seemed to suggest the same thing. They stoppe
cyclists riding past 16 roadside locations in Vermont in 1994. 76
agreed to a 5 minute interview. Only 8% were wearing helmets whe
interviewed. 19% said they owened a helmet, but 24% of helmet owner
said they didn't wear the helmet because of discomfort. When aske
about head hitting and head injuries, 21 of the 516 riders reporte
falling and hitting their heads in the past 18 months. 8 wer
helmeted, 13 not (4 lacerations, 3 concussions, 6 no head injury).

Unfortunately, cyclists were not asked how often they wore helmets,
but it would be reasonable to assume the proportion wearing helmets
when they were stopped was indicative of wearing rates in general. If
you do the sums, that means 8 cases of head hitting in about 40
helmeted cyclists, compared to 13 out of about 476 non-helmeted
cyclists. This would again strongly suggest helmet wearing is
associated with head hitting. Of course, it may simply be that helmet
wearers tend to do a lot more riding, but it would be hard to explain a
difference of that magnitude (20% vs 2.7%) just by the amount of
cycling. As far as head injury rates are concerned, the 3 concussions
out of roughly 476 non wearers, (0.6%) is nowhere near significantly
different from 0/40 in wearers.

Another paper (Wasserman et al. 1990, Amer J Sports Med, 18,
96-97) asked readers of 4 bicycling magazines (Bicycling USA,
BikeReport, California Bicyclist and Velo-News) to respond to a letter
to the editor in 1985, asking for reports of mishaps where the cyclist
had struck his or her head. Of those that had, 57% were wearing
helmets! The incidence of concussion weren't that different, 29% for
wearers vs 41% of non-wearers, though skull fractures ( 1% vs 11%)
facial soft tissue injuries (5% vs 18%) and neck injuries (13% in
wearers vs 7% in non wearers) appeared somehat different. The
difference in facial soft tissue injuries (where helmets wouldn't be
expected to provide a great deal of help) that some of the head impacts
in the wearers were relatively minor, perhaps being cases where a non
wearer wouldn't have hit the head.

So if head hitting rates differ - in the first Wasserman et al.
study, it would appear that wearers hit their heads 7 times more
frequently than non-wearers - then helmets are unlikely to offer any
real benefit.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


--
RogerDodger

Further sources of info for Chris BeHanna on above subject

In "Cycle Helmets the case for and against" by Mayer Hillman Polic
Studies Institute, London, 1993, p.12:

"...a study on the emergency treatment of cycle accidentsin the U
covering the 15 yearsto 1987 found 'no statistical evidencetha
hard-shell helmets have reduced head injury or fatality rates', an
concluded that increasing helmet wearing is actually associated with a
increase in injuries (Rodgers, 1988)."

Rodgers, G.B. (1988), 'Reducing Bicycle Accidents: A Re-evaluation o
the Impacts of the CPSC Bicycle Standard and Helmet Use', -Journal o
Products Liability-, 11, 307 - 17.

More to come...

Roge

--
RogerDodger

Further sources of info for Chris BeHanna on above subject

In "Cycle helmet effectiveness in New Zealand" , L.J. Povey, W.J.Frith
P.G. Graham, (of the Land Transport Satety Authority NZ), Acciden
Analysis and Prevention, 31 (1999) 763-770.

take a look at Fig.2 and Fig.3 on page 765 - the the titles og th
two graphs are graph swapped by mistake as "Cyclists admitted t
hospital with head injuries" and "Hospitalised cyclists with lim
fractures" Both graphs display an unexplained sharp jump in the total
of limb fracture and head injury admissions, from 1992 to 1993 and i
the case of limb fracture admissions the gradually decreasing yearl
total of ~350 in 1992 jumps to ~460 in 1993 and then just slightly dip
to values ~440, ~430, then back up to ~460 in 1996. This increase o
limb fractures needs explanation - it occurs in the year prior to th
introduction of the MHL - it could be associated with the increase o
helmet wearing or something else perhaps?
One thing's for sure this sharp jump ramped down the ratio of HI/lim
admissions hinging at the year before the MHL and thus giving th
appearance of a helmet effect. It's difficult to describe verbally wha
is so easily depicted graphically but in summary there appears
continuing downward trend in HI admissions - apart from a unexplaine
blip up in 1993 and limb admissions ramp up approx 20-25% from '92 -'9
and stay thereabouts - open to interpretation but very curious.

All of this probably means little if you don't have a copy of th
research.

Roge

--
RogerDodger

On Sat, 14 Aug 2004 12:52:47 -0400, Frank Krygowski wrote:

Chris BeHanna wrote:

I guess the only way we could *really* know, is if we could
compile a large enough number of reports of cyclists who hit their
heads while wearing helmets vs. those who hit their heads while not
wearing helmets, and look at the results. That would take
risk-aversion completely out of the discussion.

To illustrate how complex this problem really is: Even that wouldn't be
foolproof. There are factors that cause helmeted riders to hit their
"heads" (actually, helmets) more often.

One reason is that the helmet is larger than the head. Obviously, there
are crashes that would have been a near miss to a person's scalp, but
where the helmet gives a startling "bang" on the pavement. (I'd bet
this causes a large percentage of the "My helmet saved my life!" stories.

Such stories wouldn't result in a trip to the hospital for a head
injury, however. They shouldn't skew the results.

A second reason is that riders feeling more protected are apt to take
more risks. ("Risk compensation.") If these risks result in the helmet
impacting the ground, the very presence of the helmet has effected the
"experiment."

Both yours and Guy's points are well-taken.

I think what you'd like to see is some double-blind study involving
helmets of current protective value, but zero thickness. Obviously,
this isn't possible!

I'd like to see some data that actually provides useful
information to allow cyclists to make informed decisions, free of pro-
or anti-helmet zealotry or influence, with specific enough methods
that the results do not require much, if any, interpretation.

It doesn't look like that is coming any time soon, alas.

Anyway, thank you for your civility.

--
Chris BeHanna
Software Engineer (Remove "allspammersmustdie" before responding.)

I was raised by a pack of wild corn dogs.

On Sun, 15 Aug 2004 16:14:44 GMT, Chris BeHanna
wrote:

On Sat, 14 Aug 2004 12:52:47 -0400, Frank Krygowski wrote:

Chris BeHanna wrote:

I guess the only way we could *really* know, is if we could
compile a large enough number of reports of cyclists who hit their
heads while wearing helmets vs. those who hit their heads while not
wearing helmets, and look at the results. That would take
risk-aversion completely out of the discussion.

To illustrate how complex this problem really is: Even that wouldn't be
foolproof. There are factors that cause helmeted riders to hit their
"heads" (actually, helmets) more often.

One reason is that the helmet is larger than the head. Obviously, there
are crashes that would have been a near miss to a person's scalp, but
where the helmet gives a startling "bang" on the pavement. (I'd bet
this causes a large percentage of the "My helmet saved my life!" stories.

Such stories wouldn't result in a trip to the hospital for a head
injury, however. They shouldn't skew the results.

Personal testimonials are awfully effective at influencing individual
decisions though. We're never rational actors anyway.
snip

-Luigi

Chris BeHanna wrote:



I'd like to see some data that actually provides useful
information to allow cyclists to make informed decisions, free of pro-
or anti-helmet zealotry or influence, with specific enough methods
that the results do not require much, if any, interpretation.

It doesn't look like that is coming any time soon, alas.

Unfortunately, this issue has been on the table long enough that you're
unlikely to find knowledgeable opinions free of "pro" or "anti"
influence. (Although almost all "anti-helmet" folks are actually not
trying to outlaw helmets; if anything, most of those folks are either
pro-cycling or anti-bull****.)

What I mean is: I've studied this issue for at least ten years. In the
very beginning, although I was anti-compulsion, I was pro-helmet. I
recommended their use.

After years of study, reading dozens of serious research papers and
discussion of those papers, I became convinced that helmets are being
greatly oversold, and that they are neither generally necessary nor as
protective as claimed. And, BTW, from what I read here, most people
seem to move in the direction I moved when they learn more about the issue.

In any case, people who are interested enough in this issue have an
opinion (even if it's just "My company needs to increase its helmet
sales!" or "We must protect the children in any way possible!!"). So
you're unlikely to find people who have anything to contribute but who
have no opinion.

But it's that way with most issues in life. Really, the best thing to
do is to read a bunch of the papers, and track down the discussion of
them (because it's not unusual for authors to be proven wrong). Then
make your own decision.


Anyway, thank you for your civility.

No problem.


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

On Sun, 15 Aug 2004 13:31:26 -0400, Frank Krygowski
wrote in message :

After years of study, reading dozens of serious research papers and
discussion of those papers, I became convinced that helmets are being
greatly oversold, and that they are neither generally necessary nor as
protective as claimed. And, BTW, from what I read here, most people
seem to move in the direction I moved when they learn more about the issue.

You are me and I claim my five pounds )

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

"Chris BeHanna" wrote in message
newsan.2004.08.14.14.52.53.85302@allspammersmust die.behanna.org...
On Sat, 14 Aug 2004 02:01:22 +0000, Tom Kunich wrote:

"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.

No, in point of fact, it has *NOT*. I've received pointers to
numerous studies that show quite convincingly that mandatory helmet
laws do not work, and I believe them.

I have yet to see one single table that shows the percentage of
people treated for head injuries who were wearing helmets, vs. the
people treated for head injuries who were not wearing helmets. THAT
is the nugget I'm after, and based upon a critique I've found
regarding FARS helmet use data, it appears that I'm unlikely to get
it. :-(

Not trying to provoke you Chris but you see, there was no way of knowing if
they were or if they weren't because that sort of information hasn't been
garnered until lately.

But here's the kicker - when you look at a time study of fatalities before
and after a large increase in helmet use and see no change and you ask the
sort of question you did, your implication is that those who don't wear
helmets are those who get involved in all of the accidents. In effect you're
claiming that there is an accident prone group who are responsible for all
of the accidents. To expand upon that, it also excuses drivers, often
seriously BAD drivers from the profound results of their carelessness since
we are saying that there is an accident prone group of bicyclists who are
the CAUSE of fatal and serious accidents.

And that I sincerely refuse to even consider appropriate. And I don't
believe that you really mean that and have merely not considered the full
implications of your ideas.

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.

Sigh. You misunderstand me.

No, I didn't mean that in a inculpatory manner. I think that you simply do
not believe that helmets would not work even if you fully understood the
minute effects a helmet could have in major collisions.

I wear a helmet because I BELIEVE (though tests don't particularly support)
that they are effective in minor accidents in which you may whack your head
on the road, trail or some other object. Since I have spent a lifetime
falling I have a pretty good falling technique and have never hit my head
hard before. But as a safety precaution I think it probably adviseable to
wear one for those accidents in which I MAY hit my head.

And let me say this: I'm not just some guy who looked up a few papers on
helmets because I didn't like them. Of COURSE I didn't like them but I was
riding alone out in the desert on motorcycles and it seemed smart to have
some sort of protection when riding off cliffs or into quicksand pits. Then
racing motorcycles became my hobby and helmets were mandatory. A few friends
died without helmets on and I started reading up on helmets to find reasons
to convince people to use helmets. When I read the helmet standards I was
aghast. Then when I read a few medical reports on people who died wearing
helmets I was pretty much convinced that they not only didn't work as billed
but that it was impossible to make a helmet that could provide even a fair
amount of protection to the head.

I became the safety director for the American Federation of Motorcyclists
and studied helmets seriously. And with each paper I read I had a growing
uneasiness. All of the studies seemed to be very pro-helmet and were
reporting findings that my understanding of the physics of crashes and the
standards themselves would indicate were impossible.

I even talked to Dr. Shively at the Snell Memorial Institute and while he
danced around the questions a little he pretty plainly agreed with me. His
basic opinion seemed to me to be, "I know that they don't do what is claimed
for them but they DO do something and that is better than nothing."

I agree with that position but I don't believe that it reaches the level of
protection which would make it intelligent or even advisable for helmet
wearers or even safety directors to make full population mandates. And
certainly I find it less than acceptable to be riding along the road with
someone without a helmet on and have every other rider who passes exclaim,
"Where's your helmet stupid?"

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.

I think about my head first anyway. Don't you?

I do because I started out without wearing helmets. Many have never fallen
and hit their heads without a helmet on and found out how painful it can be
without even leaving a bump! It requires some experiences like that to
instill in you the instinct for protecting your head first and foremost. And
those instincts can safe your life with more regularity than a helmet can.

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.

That's conjecture. A belief that in an accident of the type in
which a helmet can be of some benefit, you'll be able to control your
head, is what I'd call "hubris."

Not at all. I fell a great deal in the early days of mountain biking. Heavy
bikes with questionable handling on unstable surfaces tend to be a bit
unpredictable at times. And yet I never hit my head once without a helmet
and would wack my head quite a bit while wearing a helmet. So either the
helmet's extra weight and size were causing the head strikes or I was acting
differently in a fall with a helmet on. I opt for a combination of those two
reasons.

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.

You'll get no argument from me on this point.

BTW I put down "February, Fitness Magazine" when it was in the September
2004 issue - the latest one on the stands. In the lab waiting room it was
the only non-supermarket tabloid reading material.

Chris BeHanna requested info on the following subject:

A Bicycling Mystery: Head Injuries Piling Up

New York Times, 29th July 2001
by Julian E Barnes

Millions of parents take it as an article of faith that putting
bicycle helmet on their children, or themselves, will help keep the
out of harm's way.
But new data on bicycle accidents raises questions about that. Th
number of head injuries has increased 10 percent since 1991, even a
bicycle helmet use has risen sharply, according to figures compiled b
the Consumer Product Safety Commission. But given that ridership ha
declined over the same period, the rate of head injuries per activ
cyclist has increased 51 percent [1] just as bicycle helmets hav
become widespread.

What is going on here? No one is very sure, but safety experts stres
that while helmets do not prevent accidents from happening, they ar
extremely effective at reducing the severity of head injuries when the
do occur. Almost no one suggests that riders should stop wearin
helmets, which researchers have found can reduce the severity of brai
injuries by as much as 88 percent.

Still, with fewer people riding bicycles, experts are mystified as t
why injuries are on the rise. "It's puzzling to me that we can't fin
the benefit of bike helmets here," said Ronald L. Medford, th
assistant executive director of the safety commission's hazar
identification office.
...
see rest of article at http://www.cyclehelmets.org/1028.htm

--
RogerDodger