published helmet research - not troll

Peter writes:

Bill Z. wrote:

Peter writes:

Bill Z. wrote:


The reduction is due to traffic conditions, which have gotten worse.

The traffic conditions didn't change appreciably between the year
before the helmet law was enacted and the year after. Yet there was a
very obvious effect on the number of bicycles in the school racks.

We had basically zero decline the year the helmet law went into effect,
and I'm in the Bay Area too. Most of the kids had helmets anyway (even
if just tied to the bike).


The things you describe don't happen at any of the three schools that
I pass.

They happen in a school nearby where I live. The parking area is set
for diagonal parking right in front of the school, so parents pull
over, facing the wrong way, and then continue, driving the wrong way
in or near the bike lane until they can cross. It is very
disconcerting to see a car moving straight towards you on the wrong
side of the road, with no idea of the driver notices you or not.


Your claim was that the helmet law can't affect ridership since it's
not enforced by the police. But at least in my neighborhood it is
enforced by the schools and anyone who wants to ride to school must at
least wear a helmet when on the school grounds. This requirement was
made clear both to the children and to parents during back-to-school
activities.

So they'll take it off once off the school grounds, and no one
anything about it.


I had one in the '50s - when were they "not available?"

They weren't available where I lived ... at least I never saw anyone
use one. With no demand, that might not be surprising.


It was mostly a "little kids ride
bikes" thing. If it isn't one excuse, it's another, but I see no
reason to blame helmets.

The 30% or so drop in ridership when surveys were done in NZ and
Australia just before and after helmet laws went into effect would
seem to be one good reason. I didn't keep any statistics at the
schools I observed, but there was a similar drop.

I don't believe you ... I saw no such drop in the year the helmet law
went into effect and we live in the same general area. Are things
*that* different on the other side of the bay? I've no idea about
Australia or NZ, but maybe the law was actually enforced there. It
sure hasn't been where I live.

--
My real name backwards: nemuaZ lliB

Bill Z. wrote:
Steven Bornfeld writes:


Frank Krygowski wrote:

Steven Bornfeld wrote:



Yeah, yeah. I'll bet he hates helmets too.

:-) The intellectual level of the discussion seems to be falling
like a stone.
He did study the issue of benefits versus detriments of cycling when
he was researching the helmet issue, true. And it's partly for that
reason that he is strongly against mandating helmets, and very
cautious about even promoting them.
Give the guy credit for doing study and research before forming his
opinion, please.

Like I said. I'd be happy to seek out the study. Can you
post a reference?

Steve


This was also beaten to death a decade ago, and is being trotted out
again. The guy didn't say that helmets were ineffective. He suggested
that the health benefits of cycling regularly, even for "commuter" or
"utility" cyclists riding short distances at low speeds, exceeded the
risks whether helmets were used or not. That has zero to do with
whether helmets are effective or not. It may be a good argment
against mandatory helmet laws (depending on how much of a disencentive
a helmet requirement actually is.)


Sorry to open old wounds. ;-).
Of course, the kind of mental masturbation done to judge relative
benefits vs. risks of this type is done all the time.
Personally, I have no problem with anyone being an advocate--I am
myself. But (and it's possible I'm getting this all wrong) posting a
putatively bicycle advocacy piece which is actually a disguised
libertarian screed is a mite dishonest.
As for actually calculating the quantitative saving of lives, this is
always more complicated than it seems. I'll give you one example.
In the past year, three close friends (all male cyclists in their 50s)
have developed prostate cancer. One is terminally ill. Now, looking at
clusters of disease to advance one agenda or the other is very common
(the NY Times magazine did a piece on a BSE outbreak just a few weeks
ago), but although a few studies have been done with inconclusive
results, I still feel it is possible that there is a relationship
between cycling and prostate disease. In the kind of study which
Krygowski cited, this possibility is not on the map. Of course, it may
be in a few years.
I think an honest appraisal of the helmet issue is that what could be
dispassionately discussed as a clinical study usually degenerates into a
study of the rights of the individual vs. the government's involvement
in what is perceived to be the public interest. That these issues come
up all the time (licensing, mandatory vaccination etc.) doesn't make
them any less annoying to me.

Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY

Eric S. Sande wrote:

:-) The intellectual level of the discussion seems to be falling like
a stone.


Frank. I haven't even entered this discussion.

However there is a certain academic quality to your posts that just
naturally tends to alienate the average reader.


I can't speak for the average reader. For me, talking about my "next
Mercedes" does remind me of one of my college biochemistry professors,
whose very obvious disdain for the premed students didn't strike me as
academic in the least.

Steve

:-)



--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY

Frank Krygowski wrote:

Steven Bornfeld wrote:



Frank Krygowski wrote:

Steven Bornfeld wrote:



Well, that's the problem, isn't it? Tough to run a controlled
study of this type in real-life conditions.




It would be tough if there weren't such things as mandatory helmet
laws (MHLs). Or even better, _enforced_ MHLs. When you've got a
step increase in the percentage of cyclists in helmets for a whole
country, it's not a bad test of "real-life conditions." All you have
to do is remember to account for the decrease in cycling those laws
have caused. (Pro-helmet papers have been known to ignore a 35%
cycling drop, and count the 30% HI drop as a good sign!)




I don't know how you can call this a real test with any
control. In your response to Jay, you just said:

"Other pro-helmet studies from Australia have done things like ignore
the drop in cycling, ignore the concurrent installation of speed
cameras and stiff drunk driving enforcement, etc. to maximize the
supposed helmet benefit. Still, this is the first time I recall any
study but T&R's coming anywhere close to 85%. Despite the fudging,
other pro-helmet studies come out much lower. I'd like to check the
original paper."


If there were confounding factors in the prior example, you can't
come back and now say these can be ignored.


Do you understand that we're talking about multiple papers?

And do you understand that if the confounding factors all would tend to
decrease cyclist injuries, it's disingenuous to attribute all reduced
injuries to just one factor, the helmets?

I think it is disingenuous to say that all the other factors would
decrease cyclist injuries EXCEPT for the helmets!


I am suggesting that antihelmet partisans can be depended upon to
parse the data out there selectively.


... whereas pro-helmet partisans ...???

Sure.

Incidentally, the word "antihelmet" is rather imprecise.
"Anticompulsion" would be more accurate for many. "Anti-over-promotion"
would fit others. "Anti-fearmongering" still others. But I must say, I
can't recall anyone ever wanting to make helmets illegal.

Of course, it may be that the Church of the Helmet requires absolute
belief in _all_ pro-helmet dogma. If so, then there really are lots of
anti-helmet people.


Oh, a libertarian. Never mind--this explains it.


I've heard the same arguments from people who don't wear
seatbelts in cars. I thought they made what could be valid
points--until I spent a year covering head/neck trauma during my
residency.



So tell us about your head trauma experience. Since we're talking
about saving lives, what percentage of the head trauma fatalities you
saw were cyclists?



They don't usually call the dentist on the head trauma
fatalities. I was called on facial injuries. There were a
substantial number of cycling accidents. Most weren't wearing
helmets, but then this was 28 years ago.


Oh, a dentist.

IOW, you know something about teeth. You know relatively little about
head trauma. I should have guessed.


Ad hominem. You have no idea what I know about head trauma. Do you
want to tell me about your academic qualifications?



You probably realize that nationally, cyclists are less than 1% of
that problem, right?


If it's you, you're 100% dead.


... and, apparently, you know relatively little about evaluating
relative risk.


I personally know several people (including myself) who have suffered
head injury of various degrees while cycling. In most of these, there
was no automobile involved.
I hope you are lucky enough to have escaped serious injury, and that
your loved ones do the same.

Good luck,
Steve





--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY

On Fri, 18 Jun 2004 22:21:32 -0400, Steven Bornfeld
wrote:


You want to believe this is a helmet manufacturer conspiracy, go right
ahead.

I have no intention of wasting time proving that the earth isn't
flat.


You're a master of building straw men. Did I say anything about a
helmet manufacturer conspiracy. I've simpley asked repeatedly for
evidence that bicycle helmets are important safety devices and
suggested that given a lack of evidence proving that that helmet
proponents should be more honest and say they "hope" or "speculate"
that helmets are important. If that suggestion of honesty threatens
you so much that you have to build straw men to argue against it,
perhaps you should sit back and ask yourself why you feel threatened.

JT

John Forrest Tomlinson wrote:

On Fri, 18 Jun 2004 22:21:32 -0400, Steven Bornfeld
wrote:



You want to believe this is a helmet manufacturer conspiracy, go right
ahead.


I have no intention of wasting time proving that the earth isn't
flat.



You're a master of building straw men. Did I say anything about a
helmet manufacturer conspiracy. I've simpley asked repeatedly for
evidence that bicycle helmets are important safety devices and
suggested that given a lack of evidence proving that that helmet
proponents should be more honest and say they "hope" or "speculate"
that helmets are important. If that suggestion of honesty threatens
you so much that you have to build straw men to argue against it,
perhaps you should sit back and ask yourself why you feel threatened.

JT


JT, I'm really flattered that you consider me a master of
anything--that's high praise indeed!
I am not an epidemiologist, nor am I an actuary. It is possible that
some of these very smart people in fact have large equity positions in
helmet manufacturing companies. I posted the link of a review of
previously published clinical studies. I am not prepared to read them
and critique the design of each. If you have the time to review all of
these studies and find them flawed, more power to you.
I only raced one season--1986. You may recall that was the year that
the USOC lost its liability policy, and the USCF suspended racing until
a policy could be written. I remember the hue and cry that went up when
the hard shell helmet rule went into effect.
It is certainly understandable to me that racers who'd become
accustomed to the wind in their hair would object to the "intrusion" of
the insurance companies. Certainly there had been no studies back then
demonstrating the uselessness of helmets in preventing serious injuries,
but those I spoke to (some of whom you undoubtedly know personally) were
just as opposed to mandated helmets as you are now.
Of course, some folks are in favor of allowing performance-enhancing
drugs as well--after all, if they're administered correctly they can be
safe and effective, and it's the racers' bodies after all, isn't it?
Krygowski (and perhaps you) can probably name some safety measures that
you would acknowledge will decrease death and morbidity from bicycle
accidents. Are there any that you would mandate? Or is this more about
personal freedom than safety?

Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY

Frank Krygowski wrote:

Only in a very marginal way. They're designed to prevent a body-less
magnesium headform from exceeding 300 gees of linear acceleration in a 2
meter drop, IIRC. That's the standard - nothing more than a 14 mph
impact, and no provision for fighting rotational acceleration of the
brain.

Any idea what standard (max g's from some speed) motorcycle helmets are
designed to meet?

Joe Riel

Mark & Steven Bornfeld DDS wrote:
JT, I'm really flattered that you consider me a master of
anything--that's high praise indeed!

Hard to consider your positions when you can't even fix your user name.

Bill "multiple personalities? OK then" S.

On Sat, 19 Jun 2004 10:59:23 -0400, Mark & Steven Bornfeld DDS
wrote:
Krygowski (and perhaps you) can probably name some safety measures that
you would acknowledge will decrease death and morbidity from bicycle
accidents. Are there any that you would mandate? Or is this more about
personal freedom than safety?
Given that cycling is a fundemantally healthy activity, the only
safety thing that should be mandated are that riders generally follow
the rules of the road. And we already have laws about that everywhere
I have ever lived.

If you or anyone really care about cycling safety, I think that
teaching drivers to give other road users more respect would be
important. And better road design.

I wear a helmet most of the time when I ride both becasue I'm in a
sport where it's use is mandated (racing) and it makes sense to get
used to wearing a helmet. And I imagine that riding with a helmet is
probably a tiny bit safer than riding without one (I don't really know
that -- it's speculation).

JT

On Sat, 19 Jun 2004 10:59:23 -0400, Mark & Steven Bornfeld DDS
wrote in message
:

I posted the link of a review of
previously published clinical studies.

That'll be where you went wrong, then. Epidemiological studies based
on whole population data (including series where there are substantial
step-changes in helmet use over very short periods, like in Australia)
show no discernible benefit. Small-scale prospective studies show
benefit, but often fall apart under investigation due to basic errors.
Injury Prevention has just published a critique of one such paper by
Cook & Sheikh; they mistook percentages for percentage points (a
fairly basic statistical error) - if you correct this they are saying
that helmets are 186% effective, with every helmet protecting not only
its wearer but somebody else as well - this clearly demonstrates that
there are major confounding factors in the data for which they have
not accounted.

Many of the clinical papers are actually just literature reviews, with
remarkably few actual studies, of which the best-known is Thompson,
Rivara and Thompson's 1989 paper in the New England Journal of
Medicine. The flaws in that study are well-documented (it arrives at
a figure of 85% effectiveness by comparing poor solo urban street
cyclists with middle-class families on bike paths and attributes the
entire difference in injury rates to differences in helmet use). It
is still quoted as gospel by almost every "new" paper and literature
review, and I have only once or twice seen any explicit mention of the
known flaws in the study. In fact, if you replace the "control" group
with Rivara's own street counts from the previous year, the supposed
benefit vanishes. BHSI still quote it, despite knowing that it is
wrong, because the figure is "so ingrained in the injury prevention
community" that to use another figure would be "unhelpful". Unhelpful
to whom? Those seeking to make the case for compulsion? Or those
seeking to form a balanced judgement based on theevidence?

By the way, according to BHSI this thread is not happening ;-)


The fact that head injury rates have risen by 40% in the USA in a
period when helmet use rose from 18% to 50% surely tells us something.

As does the fact that the pro-helmet British government has admitted
that it knows of no case where cyclist safety has improved with
increasing helmet use.

It is certainly understandable to me that racers who'd become
accustomed to the wind in their hair would object to the "intrusion" of
the insurance companies. Certainly there had been no studies back then
demonstrating the uselessness of helmets in preventing serious injuries,
but those I spoke to (some of whom you undoubtedly know personally) were
just as opposed to mandated helmets as you are now.

That was not, in my opinion, an actuarial judgement; there was not
enough data to go on at the time. Quite why a device designed for a
crash at around 12mph should be mandated for racing is an interesting
philosophical question. HPV races now have helmets mandated. I have
never seen an HPV racer sustain a head injury in a crash. Several
helmeted wedgie racers have died and been brain injured in recent
times, though.

Krygowski (and perhaps you) can probably name some safety measures that
you would acknowledge will decrease death and morbidity from bicycle
accidents.

Only about 10% of cyclist injuries are to the area covered by the
helmet and many (possibly most) cyclists who die of head injury also
have other mortal injuries. Most fatal cyclist injuries are of course
sustained in crashes involving motor vehicles: it is motor traffic,
not cycling, which is dangerous.

Any "safety programme" which ignores these fundamental facts is
necessarily going to be of limited effect.


The first, best thing that can be done to improve cyclist safety is to
promote cycling. There is robust evidence from around the world that
risk falls as participation increases, for a variety of reasons.

The best thing a cyclist can do to ensure their own safety is to ride
confidently and in a vehiclular style, as per Effective Cycling (and
the equivalents in other countries such as Cyclecraft).

If you look at detailed returns on crashes you find recurrent themes:
cyclist injured by turning goods vehicle after the cyclist has gone up
the inside at a junction; cyclist hit by car emerging from junction
(which can be reduced by riding further out so you are where the
driver is looking); cyclist hit by overtaking car which turns across
their path (which can be reduced by riding further out, as the
overtaking manoeuvre is then more deliberate and reminds the driver
that you are there, rather than simply cruising by).

And of course a cyclist should ensure that their bike is well
maintained, with brakes and steering in good order.



The biggest problem with helmet promotion is that it reinforces the
perception of cycling as dangeorus without teaching any of the
techniques which reduce the danger. In doing so, it actively deters
cycling, which paradoxically /increases/ risk.

Now, I would not normally care too much about people who decide to
promote helmet use, if it weren't for the studies which show that it
deters cycling - but these days the only thing stopping some
jurisdictions from passing a helmet law is low levels of helmet use.
More than one Government has said that compulsion will be introduced
when voluntary wearing rates are high enough (at least they've learned
that much from Australia, where cycling was decimated by compulsion).

So the Liddites have persuaded Gvernments that every person who wears
a helmet is voting for compulsion. That is unacceptable.

My objections to helmet compulsion are not libertarian, but
evidence-based. We have the experience of laws in Australia, New
Zealand and Canada to draw on. In no case did injury rates reduce.
In every case cycling was deterred.



But of course, these are unwelcome messages. When you compare child
head injury rates for road crashes you find that pedestrians and
cyclists have around the same proportion of head injuries, and
pedestrian injuries are much more numerous (the risk levels in
off-road cycling for children are an order of magnitude lower). Any
justification of cycle helmet promotion applies to a much greater
extent to walking helmets. And even more so for car occupants, whose
fatality rate from head injuries is much greater. What to do?
Clearly the answer is to reduce the danger which cars pose to other
road users, but that is politically unacceptable. Cycle helmets give
the impression of "doing something" without the need to offend the
motor lobby, which is politically very attractive.

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