helmets reduce head injury by 60% and brain injuries by 58%

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mikesbytes
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helmets reduce head injury by 60% and brain injuries by 58%

Postby mikesbytes » Sun Aug 29, 2010 8:22 pm

Just noticed that the RTA NSW state that helmets reduce head injury by 60% and brain injuries by 58%

http://www.rta.nsw.gov.au/roadsafety/bi ... dgear.html
If the R-1 rule is broken, what happens to N+1?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby TheSkyMovesSideways » Sun Aug 29, 2010 8:55 pm

If they'd given a citation, we might actually be able to tell what the circumstances of the tests were. As is, it's just a vague and suspect statement of no real worth. :?
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Re: helmets reduce head injury by 60% and brain injuries by

Postby Thoglette » Sun Aug 29, 2010 10:40 pm

TheSkyMovesSideways wrote:If they'd given a citation, we might actually be able to tell what the circumstances of the tests were. As is, it's just a vague and suspect statement of no real worth. :?
And probably dates back to some newpaper article used in 1979 to "call for" mandatory helmets. Actual studies with real numbers are very thin on the ground*

*one of the problems is it;s very, very hard to work out how many kilometers are ridden in any time period. With cars, you've got statistics on fuel sold and reasonable fleet mileage statistics. Best you can do with bikes is compare head injuries to general admissions for cyclists - and that is still skewed by the quacks changing admission criteria for head injuries every decade or so.
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Re: helmets reduce head injury by 60% and brain injuries by

Postby The Womble » Mon Aug 30, 2010 6:06 am

I love how you guys find the negative in everything. If youre unsure about how they test helmets then do some research into ANSI standards and testing pocedures. They test cars for safety in specific ways but Im sure you wouldnt argue airbag and seatbelt safety with the salesman when car shopping would you? Or would you?
ANSI only test things like this in specific ways and you find that these tests are performed without bias, and are designed to simulate. As a result the tests are engineered according to data gathered on govt and international figures relating specifically to head injuries.
If they test any part of a helmet for an impact at a given angle, who here would say "well yes but what if the impact was 2mm to the left or the angle was 4 degrees different?"
guess it plain sucks when evidence comes to light that supports the use of helmets.
Maybe these report figure vary from others, but the fact remains that helmets do help reduce head injuries

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Re: helmets reduce head injury by 60% and brain injuries by

Postby sogood » Mon Aug 30, 2010 7:19 am

Volunteers are still being called for the hammer test. First with a helmet and then without... :wink:
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Re: helmets reduce head injury by 60% and brain injuries by

Postby The Womble » Mon Aug 30, 2010 7:23 am

sogood wrote:Volunteers are still being called for the hammer test. First with a helmet and then without... :wink:
How much do they pay?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby mikesbytes » Mon Aug 30, 2010 8:29 am

The bottom line is that no amount of calls for helmet laws to be repelled are going to be successful if the Govt believes that helmets make a significant reduction in head/brain injuries.
If the R-1 rule is broken, what happens to N+1?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby sogood » Mon Aug 30, 2010 9:31 am

The Womble wrote:
sogood wrote:Volunteers are still being called for the hammer test. First with a helmet and then without... :wink:
How much do they pay?
Usually no longer required after the test. :wink:
Bianchi, Ridley, Tern, Montague and All things Apple :)
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Re: helmets reduce head injury by 60% and brain injuries by

Postby TheSkyMovesSideways » Mon Aug 30, 2010 10:36 am

mikesbytes wrote:The bottom line is that no amount of calls for helmet laws to be repelled are going to be successful if the Govt believes that helmets make a significant reduction in head/brain injuries.
Disagree. The government is not a monolithic entity, and if it came to discussion in Parliament I suspect actual studies would carry a lot more weight than the opinion of RTA NSW.
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Re: helmets reduce head injury by 60% and brain injuries by

Postby trailgumby » Mon Aug 30, 2010 2:05 pm

+1. Solid evidence eventually counts for something.

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Re: helmets reduce head injury by 60% and brain injuries by

Postby jules21 » Mon Aug 30, 2010 2:26 pm

TheSkyMovesSideways wrote:The government is not a monolithic entity, and if it came to discussion in Parliament I suspect actual studies would carry a lot more weight than the opinion of RTA NSW.
+1

like this one?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby The Womble » Mon Aug 30, 2010 2:39 pm

show me any scientific evidence from any major credible study into helmet safety that doesnt show the same or similar results. Id say its a losing battle youre fighting if youre looking to disprove the potential of a helmet to save a life

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Re: helmets reduce head injury by 60% and brain injuries by

Postby mikesbytes » Mon Aug 30, 2010 3:03 pm

TheSkyMovesSideways wrote:
mikesbytes wrote:The bottom line is that no amount of calls for helmet laws to be repelled are going to be successful if the Govt believes that helmets make a significant reduction in head/brain injuries.
Disagree. The government is not a monolithic entity, and if it came to discussion in Parliament I suspect actual studies would carry a lot more weight than the opinion of RTA NSW.
Hi Dave, I wish you luck, but if I was a betting man, I wouldn't put good odds on you succeeding.
If the R-1 rule is broken, what happens to N+1?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby TheSkyMovesSideways » Mon Aug 30, 2010 3:22 pm

The Womble wrote:show me any scientific evidence from any major credible study into helmet safety that doesnt show the same or similar results. Id say its a losing battle youre fighting if youre looking to disprove the potential of a helmet to save a life
Still clinging to strawman arguments then, are we?

Questioning the effectiveness and value of mandatory helmet legislation does not equate to attempting to "disprove the potential of a helmet to save a life". :roll:
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Re: helmets reduce head injury by 60% and brain injuries by

Postby vitualis » Mon Aug 30, 2010 3:46 pm

mikesbytes wrote:The bottom line is that no amount of calls for helmet laws to be repelled are going to be successful if the Govt believes that helmets make a significant reduction in head/brain injuries.
I think that we should stop arguing whether helmets reduce the rate of head injury in the setting of an individual serious accident. The suggestion that they don't will never be seen as credible and probably isn't even true. This is also not the pertinent question that should be asked.

The question rather is whether compulsory helmet laws are beneficial to society as a whole. I would argue (as has many people from a public health perspective) that the negative externality of compulsory helmet laws far outweigh the benefits of a slight decrease in the absolute rate of head injuries and death resulting from bicycle accidents.

From an international perspective, there are very few countries with compulsory helmet laws (and I know no Westernised nations considering the application of such) so Australia is definitely an outlier. Either we are (i) simply ahead of other nations in terms of the application of rational legislation; (ii) have a unique situation; (iii) the legislation is not rationally based (e.g., the result of a "preference" rather than based on evidence); or (iv) we are behind other nations in terms of the application of rational legislation.

There are many changes in behaviour that will improve public safety but that does NOT imply that such changes should necessarily be legislated. Let me give you an example: although drink driving is considered a crime, you are actually much more likely to be killed drink walking (on a fatality/km travelled basis). That is, you are more likely to be killed leaving your car parked at the pub and walking home after a few drinks than driving home. Does that mean we should outlaw "drink walking"?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby jules21 » Mon Aug 30, 2010 3:50 pm

vitualis wrote:There are many changes in behaviour that will improve public safety but that does NOT imply that such changes should necessarily be legislated. Let me give you an example: although drink driving is considered a crime, you are actually much more likely to be killed drink walking (on a fatality/km travelled basis). That is, you are more likely to be killed leaving your car parked at the pub and walking home after a few drinks than driving home. Does that mean we should outlaw "drink walking"?
of course not - it would be impractical. but can the same be said of helmet laws? this is much less clear.

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Re: helmets reduce head injury by 60% and brain injuries by

Postby vitualis » Mon Aug 30, 2010 4:06 pm

Actually, it's not impractical at all; arguably, setting up RBT for motor traffic is more difficult than setting up an RBT for pedestrians down the road from a pub. Many countries at various times have instituted alcohol abstinence laws to varying levels of success. The reasons for NOT legislating against "drink walking" has nothing to do with the impracticality of the application of such a law. Rather, it is questionable whether the flow on effects from such a law is worth the small improvement in public safety. Moreover, there are probably better strategies to reduce this risk than the use of law (e.g., encouraging people to catch a taxi).

As for that Canadian study, I have not read it in any detail but this has to be balanced with a number of other studies that have demonstrated the opposite effect (that is, taking the evidence base as a whole rather than cherry picking the information you want). Moreover, one needs to consider the possibility of a "type 2 error". Furthermore, whether the application of compulsory helmet laws in itself lowers the rate of cycling is of somewhat lesser importance to some contemporary issues; i.e., its effect on encouraging the uptake of cycling in the setting of mass city bicycle hire programs. It should be patently obvious that the failure of the Melbourne scheme compared to the success of multiple schemes around the world hinges on one critical component.

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Re: helmets reduce head injury by 60% and brain injuries by

Postby jules21 » Mon Aug 30, 2010 4:11 pm

vitualis wrote: It should be patently obvious that the failure of the Melbourne scheme compared to the success of multiple schemes around the world hinges on one critical component.
i think that is beyond debate, but the Bike Hire Scheme is only a small part of broader cycling. it's also solvable by hiring out helmets, which remains an option.
vitualis wrote:As for that Canadian study, I have not read it in any detail but this has to be balanced with a number of other studies that have demonstrated the opposite effect.
it's hard to argue with "a number of other studies" :)

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Re: helmets reduce head injury by 60% and brain injuries by

Postby The Womble » Mon Aug 30, 2010 4:24 pm

TheSkyMovesSideways wrote:
The Womble wrote:show me any scientific evidence from any major credible study into helmet safety that doesnt show the same or similar results. Id say its a losing battle youre fighting if youre looking to disprove the potential of a helmet to save a life
Still clinging to strawman arguments then, are we?

Questioning the effectiveness and value of mandatory helmet legislation does not equate to attempting to "disprove the potential of a helmet to save a life". :roll:
when was the thread ever about the legal requirement to wear one?

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Re: helmets reduce head injury by 60% and brain injuries by

Postby Missy24 » Mon Aug 30, 2010 4:55 pm

sogood wrote:
The Womble wrote:
sogood wrote:Volunteers are still being called for the hammer test. First with a helmet and then without... :wink:
How much do they pay?
Usually no longer required after the test. :wink:
And they say I'm trouble :wink:

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Re: helmets reduce head injury by 60% and brain injuries by

Postby TheSkyMovesSideways » Mon Aug 30, 2010 4:58 pm

The Womble wrote:when was the thread ever about the legal requirement to wear one?
2nd post by mikesbytes in this thread. Not sure what that's got to do with the post you're quoting though.
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Re: helmets reduce head injury by 60% and brain injuries by

Postby vitualis » Mon Aug 30, 2010 5:14 pm

With regards to evidence:
I think that there is pretty good evidence that helmets reduce the rate of head injuries. Here is a meta-analysis of five well controlled studies published in the Cochrane Database of Systematic Reviews: http://onlinelibrary.wiley.com/o/cochra ... frame.html

The recent Canadian study is here:
http://injuryprevention.bmj.com/content ... 9.abstract [abstract]
For all of you who don't have access to the full article, here it is:
https://docs.google.com/fileview?id=0Bw ... 4&hl=en_GB

jules21, the authors of the study list some of the articles that demonstrate a decline in cycling in their "discussion".

Now that I've read the study, there are some (serious) methodological limitations of this study. Firstly, the adherence rate for wearing helmets in the Canadian provinces with helmet laws is rather low, even those with mandatory helmet laws for all ages (Prince Edward Island). Secondly, there is significant helmet wearing in the province examined without any mandatory laws (Saskatchewan). Thirdly, the pre-legislation rates of cycle commuting (in adults at least) is quite low (4%) in the province that introduced the mandatory helmet laws (Prince Edward Island). Lastly, the authors gloss over some changes in "bicycle ridership" that is relatively unexplained. The "mean number of times bicycled" dropped substantially for youth in Alberta in 2007 (helmet laws for < 18 yo) and dropped significantly for adults Prince Edward Island in 2007 (manadatory helmet for all). Although these changes may well be related to factors other than helmet laws, the inability to account (or control) for these factors in their dataset again increases the likelihood of a type 2 error (i.e., their study was underpowered to detect a real effect that might be present).

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Re: helmets reduce head injury by 60% and brain injuries by

Postby jules21 » Mon Aug 30, 2010 5:25 pm

vitualis wrote: Firstly, the adherence rate for wearing helmets in the Canadian provinces with helmet laws is rather low, even those with mandatory helmet laws for all ages (Prince Edward Island).
i don't see how that's a limitation on the study - all that realy matters is whether helmet laws increase wearing rates - even if only by a finite amount. if they don't, then the argument that they reduce cycling rates must be rescinded. i think you're trying to have it both ways, there.
vitualis wrote: Secondly, there is significant helmet wearing in the province examined without any mandatory laws (Saskatchewan).
i don't see any reason why there shouldn't be.
vitualis wrote: Thirdly, the pre-legislation rates of cycle commuting (in adults at least) is quite low (4%) in the province that introduced the mandatory helmet laws (Prince Edward Island).
that seems high to me!
vitualis wrote:Although these changes may well be related to factors other than helmet laws, the inability to account (or control) for these factors in their dataset again increases the likelihood of a type 2 error (i.e., their study was underpowered to detect a real effect that might be present).
but you've got it the wrong way around. the onus is really on those who claim helmet laws reduce cycling rates, to prove it. it's up to them to navigate the difficulties with processing data, that you highlight.

while you may have highlighted a shortcoming of the study and i don't doubt you have some skill in this area, what's really needed is a peer reviewed study to rebut it.

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Re: helmets reduce head injury by 60% and brain injuries by

Postby vitualis » Mon Aug 30, 2010 5:48 pm

jules21 wrote:
vitualis wrote: Firstly, the adherence rate for wearing helmets in the Canadian provinces with helmet laws is rather low, even those with mandatory helmet laws for all ages (Prince Edward Island).
i don't see how that's a limitation on the study - all that realy matters is whether helmet laws increase wearing rates. if they don't, then the argument that they reduce cycling rates must be rescinded. i think you're trying to have it both ways, there.
vitualis wrote: Secondly, there is significant helmet wearing in the province examined without any mandatory laws (Saskatchewan).
i don't see any reason why there shouldn't be.
The point is that this weakens their data analysis. If pre-existing helmet wearing was already common without a law, the institution of a mandatory law is likely to have a lesser effect on ridership. Similarly, if after the implementation of such a law, the rates of compliance to the law is low, it is also going to have a lesser effect on ridership.

Optimally, you want the study to be done in a study population that has low helmet wearing prior to the law and then good compliance with helmet wearing after the law comes into place.

In any case, the authors do find (unsurprisingly) that mandatory helmet laws increases the rate of helmet wearing.
vitualis wrote:Although these changes may well be related to factors other than helmet laws, the inability to account (or control) for these factors in their dataset again increases the likelihood of a type 2 error (i.e., their study was underpowered to detect a real effect that might be present).
but you've got it the wrong way around. the onus is really on those who claim helmet laws reduce cycling rates, to prove it. it's up to them to navigate the difficulties with processing data, that you highlight.
Actually, you're the one who has it the wrong way around. The onus is on the authors to be able to justify their conclusions on the basis of their study. Their conclusion is that the introduction of helmet laws in Canada "was not associated with changes in ridership". My reading of their study is that there are problems with their methodology such that this conclusion may not be validly justified (this is not to say that this conclusion is actually incorrect, just that they haven't adequately demonstrated it).
what's really needed is a peer reviewed study to rebut it.
I have some sympathy for the researchers because this type of research is extraordinarily hard to do. For example, the response rate in their surveys (which mind you the authors haven't commented on their reliability because it most likely wasn't tested --> this is also a potential source of substantial bias due to problems with memory recall) is actually pretty good.

I frankly think we should move on from this question and further research should be directed at the mass bicycle hire schemes because they have been demonstrated to be very effective in many cities. Qualitative research can be done on the factors that make them successful and the factors that do not.

Addit: you mentioned that they could "hire helmets" with the bikes. Actually, this doesn't work for a number of reasons: (i) the scheme use a large number of automated hire points around the city and (ii) hygiene problems with reusable helmets and the practical issues of cleaning helmets (I think this is the reason the Melbourne scheme doesn't hire helmets). Disposable folding helmets might be a solution but I assume this will substantially increase the cost of such a scheme.

Cheers.
Michael Tam
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Re: helmets reduce head injury by 60% and brain injuries by

Postby The Womble » Mon Aug 30, 2010 6:14 pm

TheSkyMovesSideways wrote:
The Womble wrote:when was the thread ever about the legal requirement to wear one?
2nd post by mikesbytes in this thread. Not sure what that's got to do with the post you're quoting though.
Just what is your issue here?
1)The fact that there is a mountains worth of evidence out there that supports the RTAs report, and that you have nothing to disprove that helmets can and do absorb impacts that would more seriously damage an unprotected skull? Or
2)That you have nothing better to do with your day than follow me around blagging on about your Strawman crap? Maybe I should start a new Santa Doesnt Exist thread and see how long it takes for you to counter claim. :|
All those bodies that conduct testing to national/international standards and the manufacturers who spend tens of millions of dollars every year on development in an effort to produce safer more effective helmets, are plucking figures out of thin air for the lack of scientific research that they should have been doing to prove to you that helmets help to absorb and disperse the impacts that they are made for?
The RTAs report doesnt relate in any way to your wanting the choice to wear one. :?

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