It can't happen here

You really have to question the method of the study. I happen to live
in the Yokohama area where the local high schools require the bike
riding students to wear helmets. I see them every morning with their
standard white plastic bucket helmet--in their bike basket! Maybe one
out of ten actually has one on their head. I have to wonder if the
elementary kids acted similarly.

Quoted message said:

I was browsing here:

http://www.magma.ca/~ocbc/hfaq.html

When I clicked on this link:

http://www.magma.ca/~ocbc/jpeds.html

For convenience, I've copied the text below.

At first, I wondered if it was a hoax, but it seems to be
authentic--the spelling and language are not unusual for
such cross-cultural papers. Tatsuhiro Yamanaka does appear
to be a published Japanese pediatric researcher.

For those not familiar with statistics, the numbers do
support the conclusion of no significant difference for such
a study. (When an odds-ratio is 95% likely to fall on either
side of 1.00, it means that that the figures, no matter how
they may appear at first glance, suggest a 95% probability
that an effect was either positive, negative, or dead even.)

An alternative thread title was "Won't someone think of the
children?"

Cheers,

Carl Fogel

THE EFFECTIVENESS OF WEARING PEDESTRIAN HELMET WHILE WALKING
FROM HOME TO SCHOOL IN ELEMENTARY SCHOOL CHILDREN.
(from the Third International Conference on Injury Control
and Prevention, Melbourne, Australia, February 1996)

Presenter: Tatsuhiro Yamanaka, JAPAN

Author(s):
Yamanaka Tatsuhiro; Ogihara Arata
Department of Pediatrics, Yaizu Municipal Hospital, Yaizu
city, Shizuoka, Department of Public Health, School of
Medicine, Yokohama City University, Yokohama city, Kanagawa,
JAPAN.

PURPOSE: To evaluate the effectiveness of head injury
prevention among pedestrians wearing a helmet while walk.

METHOD: We performed a retrospective case control study of
head injury in elementary school children over a five-year
period in Shimizu city. Population is 240, 000 and there are
26 elementary schools in this city. The principle of the
school can decide whether helmet wearing should be a rule
for pupils, which means there are only two possible
situations, wearing or not wearing a helmet while walking.
Elementary school children are prohibited from bicycling to
school and there is no school bus system at all. The number
of head injuries and other injuries were collected from the
data sheet by the insurance system of the School Safety
Division of the National Stadium and School Health Center of
Japan.

RESULTS: There were 13 elementary schools which required
students to wear a helmet while walk. One school had changed
from wearing a helmet to not wearing a helmet during the
5-year period. The accumulated annual number of elementary
school children was 32,922 required to wear helmets, and
56,214 not required to wear helmets. The number of injuries
among children wearing helmets was 58 (0.18%), and 125
(0.22%) among children not wearing helmets during the 5-year
period. Head injuries were recorded in 4 children (0.012%)
wearing helmets and 10 (0.018%) who were not wearing
helmets.

CONCLUSION: There was no significant difference between
children wearing helmets and those not wearing helmets in
the incidence of all injuries and head injuries by Xy test.
The odds ratio for the no helmet system was 1.26 ( 0.92 to
1.71 for 95 % confidence) for all injuries and 1.46 ( 0.45
to 4.12 for 95 % confidence) for head injuries.

Silly study, silly idea.
The next idea that will come down the pipe is for EVERYONE to wear a
helmet AT ALL TIMES.

Ken
--
New cycling jersey: $49
new cycling shorts: $39
Not being a slave to the petrol pump: priceless.

Quoted message said:

CONCLUSION: There was no significant difference between
children wearing helmets and those not wearing helmets in
the incidence of all injuries and head injuries by Xy test.
The odds ratio for the no helmet system was 1.26 ( 0.92 to
1.71 for 95 % confidence) for all injuries and 1.46 ( 0.45
to 4.12 for 95 % confidence) for head injuries.

They just need to stop using the Final Fantasy game engineers as the
primary contractors for design of the routes to school.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

In article <[email hidden]>,

tiborg said:

You really have to question the method of the study. I happen to live
in the Yokohama area where the local high schools require the bike
riding students to wear helmets. I see them every morning with their
standard white plastic bucket helmet--in their bike basket! Maybe one
out of ten actually has one on their head. I have to wonder if the
elementary kids acted similarly.

Well, what they did is a pretty standard epidemiological approach.
However, it is not at all clear that they controlled for confounds such
as- which you mention- compliance with wearing the helmets or behavioral
changes while wearing the helmets. Had they gone and sampled the
compliance data, then their information would be more meaningful.
Perhaps only 10% of the children wore their helmets when out of sight of
parents or teachers; that might account for the lack of statistically
significant difference. On the other hand, if there was 100% compliance
then the lack of significant difference would suggest that the helmets
the kids are wearing are of little protective utility.

It's ironic that the prevalence rate of head injuries is so low even in
the unprotected group and yet this is such a big deal, while the hazards
of smoking, sedentariness and poor diet and such have huge effect sizes
but little is done about those. Are the school principals ordering
students to eat a balanced diet, get 30 minutes of aerobic exercise per
day and to not smoke?

Tim McNamara said:

Well, what they did is a pretty standard epidemiological approach.
However, it is not at all clear that they controlled for confounds such
as

You forgot the most important confound, in this wretched system where
children are forbidden to ride bicycles to school and must wear helmets
while walking to school. The source of head injury is children banging
their heads against the wall over the outrageous stupidity of the
adults. Usually they keep it to a mournful knock, but sometimes it just
gets out of control.

In article <[email hidden]>,

41 said:

Tim McNamara said:

Well, what they did is a pretty standard epidemiological approach.
However, it is not at all clear that they controlled for confounds
such as

You forgot the most important confound, in this wretched system where
children are forbidden to ride bicycles to school and must wear
helmets while walking to school. The source of head injury is
children banging their heads against the wall over the outrageous
stupidity of the adults. Usually they keep it to a mournful knock,
but sometimes it just gets out of control.

You're right, I overlooked that one.

Tim McNamara said:

It's ironic that the prevalence rate of head injuries is so low even in
the unprotected group and yet this is such a big deal, while the hazards
of smoking, sedentariness and poor diet and such have huge effect sizes
but little is done about those.

But people don't want to be let off the hook for being nonsmokers or
healthy eaters. They want to be let off the hook for using wasteful,
unhealthy forms of personal transportation.

Lots of folks know that cycling for transportation is the right thing
to do, and that they have no good excuse for not doing it. Pushing
helmets for cycling makes cycling seem like a risky thing to do. That
gives them a psychologically acceptable justification for not doing it.
It's no wonder that cycle helmets are an attractive idea to many
non-cyclists, especially if they also happen to be busybodies.

What I don't understand is why so many cyclists buy into a trend that
is pretty clearly contrary to their collective interests. Wearing a
helmet makes a tacit statement to non-cyclists. The cumulative
risk-elevating effects of that statement may be a lot more potent than
the cumulative protective effects of the helmets that help make it.

Riders who wear helmets and other conspicuously bike-specific gear may
think they are saying something like "I am a serious, skillful, and
responsible rider who is worthy of your respect."

What a non-cyclist is likely to hear, though, is more like "I get
around by a means that is so dangerous that I have to wear a crash
helmet-- like a skydiver, a race car driver, or a spastic. I must be
crazy! You are very wise to drive your nice safe comfortable car and
not be a foolhardy, queerly clothed masochist like me."

I think the consequences of spreading the latter perception represents
a lot more potential harm to us that the benefit conferred by bike
helmets.

Chalo

Chalo said:

What I don't understand is why so many cyclists buy into a trend that
is pretty clearly contrary to their collective interests. Wearing a
helmet makes a tacit statement to non-cyclists. The cumulative
risk-elevating effects of that statement may be a lot more potent than
the cumulative protective effects of the helmets that help make it.

Riders who wear helmets and other conspicuously bike-specific gear may
think they are saying something like "I am a serious, skillful, and
responsible rider who is worthy of your respect."

What a non-cyclist is likely to hear, though, is more like "I get
around by a means that is so dangerous that I have to wear a crash
helmet-- like a skydiver, a race car driver, or a spastic. I must be
crazy! You are very wise to drive your nice safe comfortable car and
not be a foolhardy, queerly clothed masochist like me."

I think the consequences of spreading the latter perception represents
a lot more potential harm to us that the benefit conferred by bike
helmets.

I agree. But I think it's going to be a long, long time before many
other cycling enthusiasts understand this point, let alone accept it.

One problem is that most avid American cyclists today have never seen a
magazine photo of an avid cyclist who was not under styrofoam.
_Bicycling_ magazine, _Adventure Cycling_ magazine, and the League of
American Bicyclists' magazine have long had policies against showing
American folks biking without helmets. (They give dispensation to
"ignorant" people in Europe or the Third World.) Consequently, most
avid American cyclists literally never consider riding without a
helmet.

Another problem is the inborn human tendency to use dress to indicate
their "tribe." This seems to be universal, and psychologically
important. It leads to some bizarre looks - like tribes with weirdly
modified bodies and really shocking costumes. I'm talking, of course,
about tribes that do things like shave the hair off their legs, and
wear day-glo magic symbols of their favorite corporations on their
cycling jerseys. ;-)

But worst is the real conviction of many, perhaps most, cyclists that
what they are doing _is_ actually dangerous! AFAICT, neither swimmers,
skiers, boaters, skaters, general aviation pilots, motorcyclists, nor
avid motorists are as likely to enthusiastically accept the idea that
what they do is very dangerous. It seems far easier to google links to
bike helmets and bike head injury than it is to, say, drownings and
water wings! (Guess which would _really_ save more lives per year.)

Overall, you're correct. Cyclists are excellent at shooting themselves
in the foot.

Perhaps we should have bullet-proof cycling shoes. After all, if only
_one_ toe can be saved...!

- Frank Krygowski