Helmets reduce bicycle-related head and facial injuries

On 26 May, 21:02, JMS wrote:
Some reading if you are interested in cycle helmet research:http://www.ncbi.nlm.nih.gov/pubmed/10796827


MAIN RESULTS: No randomized controlled trials were found. This review
identified five well conducted case control studies which met our
selection criteria. Helmets provide a 63%-88% reduction in the risk of
head, brain and severe brain injury for all ages of bicyclists.
Helmets provide equal levels of protection for crashes involving motor
vehicles (69%) and crashes from all other causes (68%). Injuries to
the upper and mid facial areas are reduced 65%. REVIEWER'S

CONCLUSIONS: Helmets reduce bicycle-related head and facial injuries
for bicyclists of all ages involved in all types of crashes including
those involving motor vehicles.

More details at :http://mrw.interscience.wiley.com/co...icles/CD001855...

I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.

That is as expected, and runs counter to the diet of inexpert claims
we hear on cycling newsgroups that they only work for slight injury
and simple spills, and do not work in accidents with other vehicles.

Fatal cycling accidents usually result from severe collision with
other vehicles, and there is also some interesting information and
data in the Transport Research Laboratory's recent report PPR438

'Analysis of police collision files for pedal cycling fatalities in
London,2001 - 2006',

The wider TRL report PPR 446 'The potential for cycle helmets to
prevent injury - a review of the evidence' is also interesting. (The
same, plus additional fatality data is discussed in Appendix H and
lists the effect of helmets making a significant difference in
severity of head trauma being the main cause of fatality).

Both reports are downloadable by registering (free) on TRL website
http://www.trl.co.uk/online_store/

They support the other reasonable evidence that helmets are effective,
can give advantages in all types of accidents and can mitigate
(sometimes crucially) the level of trauma throughout the whole
spectrum of mild to severe.

Toom

In message
Toom Tabard wrote:


I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.


I also note included amongst the following are :-

References to studies included in this review

Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a


References to studies excluded from this review

Spaite 1991

Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
prospective analysis of injury severity among helmeted and nonhelmeted
bicyclists involved in collisions with motor vehicles. Journal of Trauma
1991;31(11):1510-6.

Which had some interesting findings that initially goes along quite well
with Thompson's reported observations above.

http://tinyurl.com/2vav626

Abstract: To evaluate the impact of helmet use on injury severity,
patient information was prospectively obtained for all bicyclists
involved in collisions with motor vehicles seen at a level-I trauma
center from January 1986 to January 1989. Two hundred ninety-eight
patients were evaluated; in 284 (95.3%, study group) cases there was
documentation of helmet use or nonuse. One hundred sixteen patients
(40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine
patients (70.1%) had an ISS 15, while 85 (29.9%) were severely
injured (ISS 15). Only 5.2% of helmet users (6/116) had an ISS 15
compared with 47.0% (79/168) of nonusers (p 0.0001). The mean ISS
for helmet users was 3.8 compared with 18.0 for nonusers (p 0.0001).
Mortality was higher for nonusers (10/168, 6.0%) than for helmet users
(1/116, 0.9%; p 0.025).

But then Spaite et al decided to look closer at the non-head injuries
sustained by the cyclists and they found something that is also present
in the data from some of the studies of Thompson (but not commented on
by them).

A striking finding was noted when the group of patients without major
head injuries (246) was analyzed separately. Helmet users in this
group still had a much lower mean ISS (3.6 vs. 12.9, p 0.001) and
were much less likely to have an ISS 15 (4.4% vs. 32.1%, p 0.0001)
than were nonusers. In this group, 42 of 47 patients with an ISS 15
(89.4%) were not wearing helmets. We conclude that helmet nonuse is
strongly associated with severe injuries in this study population.
This is true even when the patients without major head injuries are
analyzed as a group; a finding to our knowledge not previously
described. This implies that nonusers of helmets tend to be in higher
impact crashes than helmet users, since the injuries suffered in body
areas other than the head also tend to be much more severe. It is
possible that at least some of the ''protection'' afforded helmet
wearers in previous studies may be explained by safer riding habits
rather than solely a direct effect of the helmets themselves.


It has also been shown in other published studies that the behaviour of
non-helmeted cyclists is significantly different from helmeted cyclists
e.g. they are also less likely to have hi-viz clothing, less likely to
have lit front and back lights, and less likely to comply with traffic
regulations.

Unfortunately these additional confounding factors are not tested for in
most of the studies reporting a protective factor for helmets against
head injuries (especially the papers by Thompson et al).

Mike
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | caving, antibody engineer and
` || (_)/ (_) | \corn computer user" http://www.antibody.me.uk/

On 28 May, 18:54, Mike Clark wrote:
In message
* * * * * Toom Tabard wrote:



I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.

I also note included amongst the following are :-

References to studies included in this review

Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a

References to studies excluded from this review

Spaite 1991

Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
prospective analysis of injury severity among helmeted and nonhelmeted
bicyclists involved in collisions with motor vehicles. Journal of Trauma
1991;31(11):1510-6.

Which had some interesting findings that initially goes along quite well
with Thompson's reported observations above.

http://tinyurl.com/2vav626

* Abstract: To evaluate the impact of helmet use on injury severity,
* patient information was prospectively obtained for all bicyclists
* involved in collisions with motor vehicles seen at a level-I trauma
* center from January 1986 to January 1989. Two hundred ninety-eight
* patients were evaluated; in 284 (95.3%, study group) cases there was
* documentation of helmet use or nonuse. One hundred sixteen patients
* (40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine
* patients (70.1%) had an ISS 15, while 85 (29.9%) were severely
* injured (ISS 15). Only 5.2% of helmet users (6/116) had an ISS 15
* compared with 47.0% (79/168) of nonusers (p 0.0001). The mean ISS
* for helmet users was 3.8 compared with 18.0 for nonusers (p 0.0001)..
* Mortality was higher for nonusers (10/168, 6.0%) than for helmet users
* (1/116, 0.9%; p 0.025).

But then Spaite et al decided to look closer at the non-head injuries
sustained by the cyclists and they found something that is also present
in the data from some of the studies of Thompson (but not commented on
by them).

* A striking finding was noted when the group of patients without major
* head injuries (246) was analyzed separately. Helmet users in this
* group still had a much lower mean ISS (3.6 vs. 12.9, p 0.001) and
* were much less likely to have an ISS 15 (4.4% vs. 32.1%, p 0.0001)
* than were nonusers. In this group, 42 of 47 patients with an ISS 15
* (89.4%) were not wearing helmets. We conclude that helmet nonuse is
* strongly associated with severe injuries in this study population.
* This is true even when the patients without major head injuries are
* analyzed as a group; a finding to our knowledge not previously
* described. This implies that nonusers of helmets tend to be in higher
* impact crashes than helmet users, since the injuries suffered in body
* areas other than the head also tend to be much more severe. It is
* possible that at least some of the ''protection'' afforded helmet
* wearers in previous studies may be explained by safer riding habits
* rather than solely a direct effect of the helmets themselves.

It has also been shown in other published studies that the behaviour of
non-helmeted cyclists is significantly different from helmeted cyclists
e.g. they are also less likely to have hi-viz clothing, less likely to
have lit front and back lights, and less likely to comply with traffic
regulations.

Unfortunately these additional confounding factors are not tested for in
most of the studies reporting a protective factor for helmets against
head injuries (especially the papers by Thompson et al).

Mike
--

On Fri, 28 May 2010 18:54:47 +0100, Mike Clark
wrote:

In message
Toom Tabard wrote:


I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.


I also note included amongst the following are :-

References to studies included in this review

Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a


References to studies excluded from this review

Spaite 1991

Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
prospective analysis of injury severity among helmeted and nonhelmeted
bicyclists involved in collisions with motor vehicles. Journal of Trauma
1991;31(11):1510-6.


There will be any number of papers *not* included.

You seem not to understand how such reviews work:

Criteria are set - and then searches and reviews are carried out.

Those papers which satisfy the search or review criteria are included;
those that don't are excluded.


You do not just include a paper because you *think* that it *ought*
to be included.



As the authors of the paper comment :


Some bicycling advocates have argued that helmeted cyclists may change
their riding behavior influenced by a greater feeling of security and,
thus take more risks and be more likely to crash (Hillman 1993). The
converse argument has also been made that helmeted cyclists may ride
more carefully and that these behaviors account for the reduction in
head injury, not helmet use (Spaite 1991). We believe these arguments
to be specious. The fundamental issue is whether or not when bicycle
riders crash and hit their heads they are benefited by wearing a
helmet. Cyclists would have to increase their risk taking four-fold to
overcome the protective effect of helmets. This seems unlikely. There
are no objective data to support this risk homeostasis theory, and
now, five case-control studies have demonstrated the protective effect
of helmets.


--
Many cyclists are proving the need for registration by their contempt for the Highway Code and laws.

The answer:
All cyclists over 16 to take compulsory test, have compulsory insurance, and be registered.
Registration number to be clearly visible on the back of mandatory hi-viz vest.
Habitual law breakers' cycles confiscated and crushed.
(With thanks to KeithT for the idea)

On 28 May, 18:54, Mike Clark wrote:
In message
* * * * * Toom Tabard wrote:



I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.

I also note included amongst the following are :-

References to studies included in this review

Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a

References to studies excluded from this review

Spaite 1991

Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
prospective analysis of injury severity among helmeted and nonhelmeted
bicyclists involved in collisions with motor vehicles. Journal of Trauma
1991;31(11):1510-6.

Which had some interesting findings that initially goes along quite well
with Thompson's reported observations above.

http://tinyurl.com/2vav626

* Abstract: To evaluate the impact of helmet use on injury severity,
* patient information was prospectively obtained for all bicyclists
* involved in collisions with motor vehicles seen at a level-I trauma
* center from January 1986 to January 1989. Two hundred ninety-eight
* patients were evaluated; in 284 (95.3%, study group) cases there was
* documentation of helmet use or nonuse. One hundred sixteen patients
* (40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine
* patients (70.1%) had an ISS 15, while 85 (29.9%) were severely
* injured (ISS 15). Only 5.2% of helmet users (6/116) had an ISS 15
* compared with 47.0% (79/168) of nonusers (p 0.0001). The mean ISS
* for helmet users was 3.8 compared with 18.0 for nonusers (p 0.0001)..
* Mortality was higher for nonusers (10/168, 6.0%) than for helmet users
* (1/116, 0.9%; p 0.025).

But then Spaite et al decided to look closer at the non-head injuries
sustained by the cyclists and they found something that is also present
in the data from some of the studies of Thompson (but not commented on
by them).

* A striking finding was noted when the group of patients without major
* head injuries (246) was analyzed separately. Helmet users in this
* group still had a much lower mean ISS (3.6 vs. 12.9, p 0.001) and
* were much less likely to have an ISS 15 (4.4% vs. 32.1%, p 0.0001)
* than were nonusers. In this group, 42 of 47 patients with an ISS 15
* (89.4%) were not wearing helmets. We conclude that helmet nonuse is
* strongly associated with severe injuries in this study population.
* This is true even when the patients without major head injuries are
* analyzed as a group; a finding to our knowledge not previously
* described. This implies that nonusers of helmets tend to be in higher
* impact crashes than helmet users, since the injuries suffered in body
* areas other than the head also tend to be much more severe. It is
* possible that at least some of the ''protection'' afforded helmet
* wearers in previous studies may be explained by safer riding habits
* rather than solely a direct effect of the helmets themselves.

It has also been shown in other published studies that the behaviour of
non-helmeted cyclists is significantly different from helmeted cyclists
e.g. they are also less likely to have hi-viz clothing, less likely to
have lit front and back lights, and less likely to comply with traffic
regulations.

Unfortunately these additional confounding factors are not tested for in
most of the studies reporting a protective factor for helmets against
head injuries (especially the papers by Thompson et al).


That abstract does not say, as you claim, that they 'looked closer at
the non-head injuries'. It says they looked at the group 'without
major head injuries'

If you score for head and rest of the body separately (the latter
would be non-head injuries) that tells more. If look at those without
major head injury, there is the problem of accommodation for helmet
wearers who might only be in that group because they were wearing
helmets. If you look at those who only had head injuries, there is the
question of helmet wearers who might not be there because they were
wearing helmets,etc.

And how is that relevant to helmets giving 'equal levels of protection
for crashes involving motor vehicles' - the same as e.g simple cycle
accidents with no other vehicle? The cyclist has less control of the
circumstances and force of impact where other vehicles are involved
(i.e any safer riding habits are diluted) but the protection is the
same.
And if 'at least some of the protection' is due to rider habits, that
would not affect the situation of a helmet per se having a further
substantial mitigating effect on such injuries as are sustained.

Toom

On May 28, 10:40*pm, Toom Tabard wrote:
On 28 May, 18:54, Mike Clark wrote:





In message
* * * * * Toom Tabard wrote:

I note their statements of equal levels of protection for crashes
involving motor vehicles, and on effect of helmets in mitigating
severe brain trauma.

I also note included amongst the following are :-

References to studies included in this review

Thompson 1989 Thompson 1990 Thompson 1996 Thompson 1996a

References to studies excluded from this review

Spaite 1991

Spaite DW, Murphy M, Criss EA, Valenzuela TD, Meislin HW. A
prospective analysis of injury severity among helmeted and nonhelmeted
bicyclists involved in collisions with motor vehicles. Journal of Trauma
1991;31(11):1510-6.

Which had some interesting findings that initially goes along quite well
with Thompson's reported observations above.

http://tinyurl.com/2vav626

* Abstract: To evaluate the impact of helmet use on injury severity,
* patient information was prospectively obtained for all bicyclists
* involved in collisions with motor vehicles seen at a level-I trauma
* center from January 1986 to January 1989. Two hundred ninety-eight
* patients were evaluated; in 284 (95.3%, study group) cases there was
* documentation of helmet use or nonuse. One hundred sixteen patients
* (40.9%) wore helmets and 168 (59.1%) did not. One hundred ninety-nine
* patients (70.1%) had an ISS 15, while 85 (29.9%) were severely
* injured (ISS 15). Only 5.2% of helmet users (6/116) had an ISS 15
* compared with 47.0% (79/168) of nonusers (p 0.0001). The mean ISS
* for helmet users was 3.8 compared with 18.0 for nonusers (p 0.0001).
* Mortality was higher for nonusers (10/168, 6.0%) than for helmet users
* (1/116, 0.9%; p 0.025).

But then Spaite et al decided to look closer at the non-head injuries
sustained by the cyclists and they found something that is also present
in the data from some of the studies of Thompson (but not commented on
by them).

* A striking finding was noted when the group of patients without major
* head injuries (246) was analyzed separately. Helmet users in this
* group still had a much lower mean ISS (3.6 vs. 12.9, p 0.001) and
* were much less likely to have an ISS 15 (4.4% vs. 32.1%, p 0.0001)
* than were nonusers. In this group, 42 of 47 patients with an ISS 15
* (89.4%) were not wearing helmets. We conclude that helmet nonuse is
* strongly associated with severe injuries in this study population.
* This is true even when the patients without major head injuries are
* analyzed as a group; a finding to our knowledge not previously
* described. This implies that nonusers of helmets tend to be in higher
* impact crashes than helmet users, since the injuries suffered in body
* areas other than the head also tend to be much more severe. It is
* possible that at least some of the ''protection'' afforded helmet
* wearers in previous studies may be explained by safer riding habits
* rather than solely a direct effect of the helmets themselves.

It has also been shown in other published studies that the behaviour of
non-helmeted cyclists is significantly different from helmeted cyclists
e.g. they are also less likely to have hi-viz clothing, less likely to
have lit front and back lights, and less likely to comply with traffic
regulations.

Unfortunately these additional confounding factors are not tested for in
most of the studies reporting a protective factor for helmets against
head injuries (especially the papers by Thompson et al).

That abstract does not say, as you claim, that they 'looked closer at
the non-head injuries'. It says they looked at the group 'without
major head injuries'

If you score for head and rest of the body separately (the latter
would be non-head injuries) that tells more. If look at those without
major head injury, there is the problem of *accommodation for helmet
wearers who might only be in that group because they were wearing
helmets. If you look at those who only had head injuries, there is the
question of helmet wearers who might not be there because they were
wearing helmets,etc.

And how is that relevant to helmets giving 'equal levels of protection
for crashes involving motor vehicles' - the same as e.g simple cycle
accidents with no other vehicle? The cyclist has less control of the
circumstances and force of impact where other vehicles are involved
(i.e any safer riding habits are diluted) but the protection is the
same.
And if 'at least some of the protection' is due to rider habits, that
would not affect the situation of a helmet per se having a further
substantial mitigating effect on such injuries as are sustained.

Toom-

The psycholists claim that cycle helmets do not significantly reduce
fatal and severe head injuries in the cycling population as a whole,
that helmets offer little protection in high speed impacts, and that
wearing helmets can change the behaviour of both cyclists and drivers,
for the better or for the worse.

There has been a significant reduction in cyclist KSI figures over the
period in which cycle helmet wearing has become more commonplace. Some
protection is usually better than non. Does the fact that the more
safety concious cyclists tend to wear helmets outweigh risk
compensation by others?

IMHO, the only way to find out if cycle helmets are effective is to
look at hospital studies, because this is when the things have
actually been tested in real life accidents. Perhaps the studies
should include the circumstances of the accident, the severity of the
injury and the outcome, e.g death, permanent diasablement, or complete
recovery.

Derek C

Derek C wrote:

There has been a significant reduction in cyclist KSI figures over the
period in which cycle helmet wearing has become more commonplace.

And has been pointed out to you numerous times, correlation and
causation aren't necessarily bedmates. The KSI figures for
pedestrians has gone down at about the same rate as for cyclists
over the same period.

Does the fact that the more
safety concious cyclists tend to wear helmets outweigh risk
compensation by others?

That's a good question. The data we have doesn't really allow us
to get a robust answer.

IMHO, the only way to find out if cycle helmets are effective is to
look at hospital studies, because this is when the things have
actually been tested in real life accidents.

Population studies show what has actually happened to /everyone/
cycling. All the helmets tested in real life accidents will have
been worn by members of the whole population, so if they get to
pretty much any hospital then they'll be in the population data set
where they can influence the figures accordingly (and of course if
they're /not/ in there having not gone to hospital because of their
helmet then they'll register with a reduction in the rates of
cyclists presenting with serious head injuries, though it seems
that doesn't actually happen).

If the hospital studies you like so much were worth much for giving
a solid answer they'd come up with reproducible numbers, but AFAICT
from having looked at plenty they don't. One thing about the
population studies is they at least manage to come up with the same
general answer (that is, ca. zero effect with (potentially large)
error bars).

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

On May 29, 12:36*pm, Peter Clinch wrote:
Derek C wrote:
There has been a significant reduction in cyclist KSI figures over the
period in which cycle helmet wearing has become more commonplace.

And has been pointed out to you numerous times, correlation and
causation aren't necessarily bedmates. *The KSI figures for
pedestrians has gone down at about the same rate as for cyclists
over the same period.

Does the fact that the more
safety concious cyclists tend to wear helmets outweigh risk
compensation by others?

That's a good question. *The data we have doesn't really allow us
to get a robust answer.

IMHO, the only way to find out if cycle helmets are effective is to
look at hospital studies, because this is when the things have
actually been tested in real life accidents.

Population studies show what has actually happened to /everyone/
cycling. *All the helmets tested in real life accidents will have
been worn by members of the whole population, so if they get to
pretty much any hospital then they'll be in the population data set
where they can influence the figures accordingly (and of course if
they're /not/ in there having not gone to hospital because of their
helmet then they'll register with a reduction in the rates of
cyclists presenting with serious head injuries, though it seems
that doesn't actually happen).

If the hospital studies you like so much were worth much for giving
a solid answer they'd come up with reproducible numbers, but AFAICT
from having looked at plenty they don't. *One thing about the
population studies is they at least manage to come up with the same
general answer (that is, ca. zero effect with (potentially large)
error bars).

Pete.
--
I have also pointed out on a number of occasions that cyclists who
wear helmets may be less seriously injured, or even uninjured, in a
given accident, so they will be less likely to be admitted to hospital
in the first place. So if anything, hospital studies will give an
under-estimate of the effectiveness of cycle helmets in preventing
deaths and serious injuries.

Derek C

Derek C wrote:
On May 29, 12:36 pm, Peter Clinch wrote:
Derek C wrote:
There has been a significant reduction in cyclist KSI figures over the
period in which cycle helmet wearing has become more commonplace.
And has been pointed out to you numerous times, correlation and
causation aren't necessarily bedmates. The KSI figures for
pedestrians has gone down at about the same rate as for cyclists
over the same period.

Does the fact that the more
safety concious cyclists tend to wear helmets outweigh risk
compensation by others?
That's a good question. The data we have doesn't really allow us
to get a robust answer.

IMHO, the only way to find out if cycle helmets are effective is to
look at hospital studies, because this is when the things have
actually been tested in real life accidents.
Population studies show what has actually happened to /everyone/
cycling. All the helmets tested in real life accidents will have
been worn by members of the whole population, so if they get to
pretty much any hospital then they'll be in the population data set
where they can influence the figures accordingly (and of course if
they're /not/ in there having not gone to hospital because of their
helmet then they'll register with a reduction in the rates of
cyclists presenting with serious head injuries, though it seems
that doesn't actually happen).

If the hospital studies you like so much were worth much for giving
a solid answer they'd come up with reproducible numbers, but AFAICT
from having looked at plenty they don't. One thing about the
population studies is they at least manage to come up with the same
general answer (that is, ca. zero effect with (potentially large)
error bars).

Pete.
--
I have also pointed out on a number of occasions that cyclists who
wear helmets may be less seriously injured, or even uninjured, in a
given accident, so they will be less likely to be admitted to hospital
in the first place. So if anything, hospital studies will give an
under-estimate of the effectiveness of cycle helmets in preventing
deaths and serious injuries.

That had occurred to me too, on reading the preceding post.

On 29 May, 12:36, Peter Clinch wrote:
Derek C wrote:
There has been a significant reduction in cyclist KSI figures over the
period in which cycle helmet wearing has become more commonplace.

And has been pointed out to you numerous times, correlation and
causation aren't necessarily bedmates. *The KSI figures for
pedestrians has gone down at about the same rate as for cyclists
over the same period.


Indeed, it is the fall in the number of cyclist KSI figures which has
resulted in cyclists displaying an increasing desire to wear helmets
as a fashion accessory.

Also of interest and great use is the discovery of the correlation
between increasing temperature and increased rate of chirping of
crickets. That means that you just need to make a few local crickets
chirp faster and you'll make it into a nice warm day. Global climate
scientists are now at work on methods to control the chirping rate of
crickets.

Toom