published helmet research - not troll

Tom Kunich wrote:

Specialized ran some tests to debunk the idea that helmets "grabbed"
the ground and caused increased rotational forces on the
brain/head/neck. They ran all the tests, looked at the data and never
published a word of it. That is significant in my book.

Interesting. Also fits in with recent developments in motorcycle helmets,
where they are trying to replicate the effect of skin sliding over the
skull. The human body is remarkably well adapted to survival, isn't it?

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

Mark & Steven Bornfeld DDS wrote:

You quite rightly demand well-designed research to demonstrate any
health benefit from helmets.
I am having great difficulty however finding any well-designed
research demonstrating that cycling improves life expectency in
age-matched populations, adjusting for confounding factors such as
diet, cigarette smoking, etc.

The source most usually quoted (in my experience) is Mayer Hillman (Cycling
towards health and safety. British Medical Association, 1992); this work is
ten years old and currently being updated.

Here are some other leads you might want to follow up:

Health, fitness, physical activity and morbidity of middle aged male factory
workers. Tuxworth et al. Br J Indus Med 1986; 43:733.

Physical activity, all-cause mortality and longevity of college alumni.
Paffenbarger et al. New England Journal of Medicine 1986; 314(10): 605-613.

Cycling and the promotion of health. Hillman M. Policy Studies vol 14, PSI
London.

All-cause mortality associated with physical activity during leisure time,
work, sports and cycling to work. Andersen LB et al. Arch Intern Med 2000;
Jun 12;160(11):1621-8.


This is not an area I have studied in any great depth, so you may well be
able to pick holes in this, in which case I'd be interested to know.

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

Bill Z. wrote:

"Riley Geary" writes:



From NHTSA, we have their official "What's New about Bicycle
Helmets" brochure at
http://www.nhtsa.dot.gov/people/inju...ead/page2.html
that states:

"Why are bicycle helmets so important?
Bicycle helmets can reduce the risk of head injury by up to 85 percent. Most
deaths related to bicycle falls and collisions involve head injuries. This
means that wearing a helmet can save your life."


"Up to 85%" is a pretty weak statment, as is "can save your life." Kind
of like saying "Brand X reduces cavities by up to 80%."

Nonetheless, this kind of misinformation and exaggeration is what is
constantly piped out by the "safety industry" and consequently, it's
what everyone "knows." Even though it's demonstrably wrong.



What I wrote was "I don't think anyone seriously claims an 85%
reduction in fatalities, nor in fatal head injuries - that is mostly a
strawman Krygowski et al. like to bring up." A serious claim is
something you'd see in respectable journal, not some brochure or some
random web site.
....

You mean like the infamous Sachs, et al "study" still available on the bhsi
website at http://www.bhsi.org/stats.htm and still cited by true believers
among helmet promoters that took the original TRT "finding" and extrapolated
it to fatalities with the ludicrous assertion that:


You guys claimed that the BHSI is simply a single individual putting up a
personal web site. Would you mind getting your story straight or at least
consistent? BTW. the title of the page you are complaining about is
"A Compendium of Statistics from Various Sources." That doesn't sound
like the sort of thing anyone should take seriously.

Obviously, Bill, you don't recognize that the Sachs paper referred to
was published in the Journal of the Amercian Medical Association, a
generally "respectable journal."

Obviously, you are YET AGAIN arguing about a paper you haven't read!

I'm amazed this sort of thing doesn't embarrass you into silence!

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

On Tue, 27 Jul 2004 19:37:58 GMT, Joe Riel wrote
in message :

Can you provide any other example of "personal protective equipment"
which is claimed to be more effective against serious injuries than
trivial ones?

The airbag might be [more effective against serious injuries than
trivial ones], considering that it can cause nontrivial injuries when
deployed. Of course, it is more a system than equipment...

Maybe, but it's nont personal protective equipment - and it only
deploys once a threshold has passed, so you can't compare it.

Although... url:http://www.sheldonbrown.com/airbag-helmet.html

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

Frank Krygowski wrote:

Steven Bornfeld DDS wrote:



Guy--

You quite rightly demand well-designed research to demonstrate any
health benefit from helmets.
I am having great difficulty however finding any well-designed
research demonstrating that cycling improves life expectency in
age-matched populations, adjusting for confounding factors such as
diet, cigarette smoking, etc.
I love to ride, and no one can tell me that it doesn't improve the
quality of my life. But I think you have to be careful to employ the
same rigorous standards to the very specific benefits you claim for
cycling.


I haven't tried to examine the strength of any "life expectancy" claims,
largely because they're unimportant to me, just as they are to you. I
don't cycle to live longer; I cycle to _live_. But random thoughts
which may or may not be pertinent:

The top four causes of death in the US are heart disease, cancer,
stroke, and lung disease. It's generally thought that cycling reduces
all of these, at least to some degree. Based on that, I'd guess cycling
causes increased longevity.

The confounding factors must make this difficult, though. Example: I
knew a female nurse who detested exercise all her life. In her 50s, she
learned she had a bad heart valve, and was told it had doubtlessly made
exercise more painful for her than for others. So "fitness" behavior
probably is self-selecting to a degree.

However, I think there's little doubt that transportational cycling
causes increased life expectancy _in others_. What with air pollution,
noise, and direct impacts, motoring certainly seems to have a negative
effect on others. Cycling doesn't do this, so it must help.

This latter stuff is what Mayer Hillman was taking into account when he
computed the ratio of years-of-life-gained vs. years-of-life-lost due to
cycling as about 20:1. But I don't know much about how he gathered his
data.


This figure is on the face of it absurd--similar in quality to the
self-serving information purporting to prove helmet efficacy.
The test design would be daunting, but if someone is going to make the
claim, they have to demonstrate evidence in an honest way.

Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001

Just zis Guy, you know? wrote:

Mark & Steven Bornfeld DDS wrote:


You quite rightly demand well-designed research to demonstrate any
health benefit from helmets.
I am having great difficulty however finding any well-designed
research demonstrating that cycling improves life expectency in
age-matched populations, adjusting for confounding factors such as
diet, cigarette smoking, etc.


The source most usually quoted (in my experience) is Mayer Hillman (Cycling
towards health and safety. British Medical Association, 1992); this work is
ten years old and currently being updated.

Here are some other leads you might want to follow up:

Health, fitness, physical activity and morbidity of middle aged male factory
workers. Tuxworth et al. Br J Indus Med 1986; 43:733.

Physical activity, all-cause mortality and longevity of college alumni.
Paffenbarger et al. New England Journal of Medicine 1986; 314(10): 605-613.

Cycling and the promotion of health. Hillman M. Policy Studies vol 14, PSI
London.

All-cause mortality associated with physical activity during leisure time,
work, sports and cycling to work. Andersen LB et al. Arch Intern Med 2000;
Jun 12;160(11):1621-8.


This is not an area I have studied in any great depth, so you may well be
able to pick holes in this, in which case I'd be interested to know.

Guy

Only one of these sources purports to even obliquely address the issue
of cycling and longevity (and one other addresses mortality by physical
activity).
My experience is that papers of this nature (as for the derided helmet
studies) use research the way a drunk uses a lamppost--for support, not
for light.
Several years back a small article by Ed Pavelka in Bicycling magazine
about cycling and perineal paresis provoked a firestorm of protest--one
must not even mention a possible health risk of cycling. Meanwhile,
three of my close friends in their 50s have developed prostate cancer in
the past two years--one is terminally ill. The doctors think the fact
that they are all cyclists and have ridden heavy mileage for years is
interesting, but that is all they can say--because the research simply
isn't there.
If we love cycling, I rather think we've a responsibility to
investigate all possible risks--not to turn folks off to cycling, but to
mitigate or minimize the risks--to make cycling the safer lifelong
activity that Paul Dudley Wright envisioned all those years ago.

Steve

--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001

Mark & Steven Bornfeld DDS wrote:
This latter stuff is what Mayer Hillman was taking into account when
he computed the ratio of years-of-life-gained vs. years-of-life-lost
due to cycling as about 20:1. But I don't know much about how he
gathered his data.


This figure is on the face of it absurd--similar in quality to the
self-serving information purporting to prove helmet efficacy.

While I wouldn't be surprised if the 'study' was bogus, it seems as
though the figure could easily by true, if somewhat meaningless.

To make things easy, assume
average life expectancy is 100 years,
1 in 1000 cyclists are killed while riding
the non-killed cyclists add one year to their life expectancy.

Further assume the average age of the killed cyclist is 50.
The ratio of expected years gained to years lost is

1 : 50/1000 = 20 : 1.

However, since you only add one year to your life expectancy, it really
isn't a big deal. The point is, the ratio is probably not a useful measure.

[anecdote]
On the other hand, I believe that one of the reasons that I survived a
major medical trauma this year was that I was in excellent physical
condition due to years of cycling.
[\anecdote]

Joe

Mark & Steven Bornfeld DDS wrote:

Frank Krygowski wrote:

This latter stuff is what Mayer Hillman was taking into account when he
computed the ratio of years-of-life-gained vs. years-of-life-lost due to
cycling as about 20:1. But I don't know much about how he gathered his
data.


This figure is on the face of it absurd--similar in quality to the
self-serving information purporting to prove helmet efficacy.

Why would you say that?
Let's run some numbers, off the top of my head, and see if Hillman
is at least within an order of magnitude, or if we can dismiss him
as lightly as you do.

Every year, ~800 out of many million cyclists are killed in the USA.
Let's assume the average age to be 25, and they lose 55 years of
life expectancy. 55x800=44,000 man-years lost in America each year.

If I cycle for 50 years, are you willing to allow me an extra 2
years of life expectancy? If so, I'm getting .04 years of life
for every year of cycling. If there are 25 million of me, then
we're saving one million man-years each year, which would imply
a gain/loss ratio of 23 to one.

Either you are using population estimates very far from mine above,
or you are dismissing published research as absurd without even
considering it first.

Mitch.

"Joe Riel" wrote in message
...
[...]
Further assume the average age of the killed cyclist is 50.
The ratio of expected years gained to years lost is

1 : 50/1000 = 20 : 1.

However, since you only add one year to your life expectancy, it really
isn't a big deal.

When it's you and that extra year is this year then I think it would be a
big deal.




--
'I believe in self-assertion, destiny or slight diversion
Now it seems I've got my head on straight
I'm a freak, an apparition .It seems I've made no right decision.'

-self

Joe Riel wrote:

Mark & Steven Bornfeld DDS wrote:

This latter stuff is what Mayer Hillman was taking into account when
he computed the ratio of years-of-life-gained vs. years-of-life-lost
due to cycling as about 20:1. But I don't know much about how he
gathered his data.


This figure is on the face of it absurd--similar in quality to the
self-serving information purporting to prove helmet efficacy.


While I wouldn't be surprised if the 'study' was bogus, it seems as
though the figure could easily by true, if somewhat meaningless.

To make things easy, assume
average life expectancy is 100 years,
1 in 1000 cyclists are killed while riding
the non-killed cyclists add one year to their life expectancy.

Further assume the average age of the killed cyclist is 50.
The ratio of expected years gained to years lost is

1 : 50/1000 = 20 : 1.

However, since you only add one year to your life expectancy, it really
isn't a big deal. The point is, the ratio is probably not a useful
measure.

[anecdote]
On the other hand, I believe that one of the reasons that I survived a
major medical trauma this year was that I was in excellent physical
condition due to years of cycling.
[\anecdote]

Joe

My younger brother moved to Florida about 15 years ago because:
1)He hated NY winters. and
2) He could afford to buy a house in South Florida; he could not in NY.
Well, there are tens, perhaps hundreds of other considerations I could
have weighed and measured if it were I making the decision to move. It
is helpful to be able to see things in the simplest possible light if
one must make a decision.
I cycle (not much anymore, sadly) because
1)I love it. and
2) It used to get me out of the house. and
3) It was the framework about which much of my social life revolved. And:
4) I thought it was likely beneficial for my health to get regular exercise.

These are all IMO very valid reasons. However, they are no where near
as stark, immutable and objectifyable as saying they will make me live
longer.
In my compulsive parsing of this issue, a couple of things come to mind:
1) The studies demonstrating longevity benefits of cycling usually
assume that vigorous regular aerobic exercise has comparable
cardiovascular benefits (reasonable)
2)That risk of dying in an accident because you are a cyclist is not
likely much higher than if you are not a cyclist (possible, but not
demonstrated clearly to my knowledge)
3) That there is no other significant morbidity associated with cycling
other than crashes (very doubtful, in my view)

Like you, I'm not too interested in determining the answer to the
question--I enjoy cycling too much. By the same token, I am in a
profession where I am daily exposed to toxic fumes, infectious agents,
and radiation. In other words, in the scheme of things, I have bigger
problems to worry about.
I would just hope that where public policy is concerned, if one side is
going to demand solid evidence before making categorical claims (totally
reasonable) that one should be careful about casual unsupported claims
that could very well undermine your credibility.

Steve


--
Mark & Steven Bornfeld DDS
http://www.dentaltwins.com
Brooklyn, NY
718-258-5001