Evaluating the impact of cycle helmet use...

For all discussions about this "lively" subject. All topics that are substantially about helmet usage will be moved here.
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deliquium
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Re: Evaluating the impact of cycle helmet use...

Postby deliquium » 11 Jul 2020, 6:39pm

reohn2 wrote:
PaulaT wrote:
Mike Sales wrote:What would be best for cycling is a road environment in which nobody feels the need for a helmet.
Some other countries show how this can be achieved, and it is not done by wearing helmets.
The figures show that helmet wearing does not improve cyclist casualty rates.
Promotion of wearing, by propaganda or example, merely diverts energy and attention from effective safety measures.
To that extent helmets are bad for improving cycling safety, or indeed numbers cycling.
They demonstrate that cycling is an unusually dangerous activity, which it is not. Very few other everyday activities are seen to need helmets. Quite reasonably, since they do not protect most of the body and seem a flimsy protection for the head, non-cyclists are not encouraged to take up cycling by the sight of cyclists wearing them.


Spot on :)

+1


Spot on + 2
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Re: Evaluating the impact of cycle helmet use...

Postby pjclinch » 11 Jul 2020, 7:58pm

The utility cyclist wrote:promoting risky/riskier cycling, is that really difficult to grasp for you? :?


Deary, deary me... that's not so much cycling as circus skills on a bike, it has nothing much in common with most of the cycling done by most cyclists and it is so obviously on a different plane that what it mainly does is inspires admiration (because we know from our grounded cycling that flying doesn't come easily), not a DIY "I wonder how easy it is to do a backflip on a bike?" session.

You are going so far out of your way to see red that you can't see anything else. I am actually on your side with a lot of points, but I'm afraid here it needs to be pointed out that you have come adrift from the plot, and as a consequence are harming your own message.
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Re: Evaluating the impact of cycle helmet use...

Postby Mike Sales » 11 Jul 2020, 8:04pm

Thanks, Reohn, Paula and Deliquium.

I thought hard about what I wanted to say and how best to express it.

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Re: Evaluating the impact of cycle helmet use...

Postby reohn2 » 11 Jul 2020, 11:31pm

pjclinch wrote:.......You are going so far out of your way to see red that you can't see anything else. I am actually on your side with a lot of points, but I'm afraid here it needs to be pointed out that you have come adrift from the plot, and as a consequence are harming your own message.

I think that about sums it up.
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Re: Evaluating the impact of cycle helmet use...

Postby Nigel » 12 Jul 2020, 1:13pm

deliquium wrote:
Mike Sales wrote:What would be best for cycling is a road environment in which nobody feels the need for a helmet.
Some other countries show how this can be achieved, and it is not done by wearing helmets.
The figures show that helmet wearing does not improve cyclist casualty rates.
Promotion of wearing, by propaganda or example, merely diverts energy and attention from effective safety measures.
To that extent helmets are bad for improving cycling safety, or indeed numbers cycling.
They demonstrate that cycling is an unusually dangerous activity, which it is not. Very few other everyday activities are seen to need helmets. Quite reasonably, since they do not protect most of the body and seem a flimsy protection for the head, non-cyclists are not encouraged to take up cycling by the sight of cyclists wearing them.


Spot on + 2


+3.

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Mick F
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Re: Evaluating the impact of cycle helmet use...

Postby Mick F » 12 Jul 2020, 6:17pm

I did 40miles today into rural Devon and back on real roads ........ A roads and B roads too. Not worn a helmet for years.
For the vast majority of the ride, I hardly saw much traffic at all.

Not because of "lock-down" but because it's generally quiet down this end ..................... despite the caravans and campervans that seem to be arriving by the day.
I really have great sympathy for riders out there where it's very busy and very horrid.

Please don't think that everywhere and anywhere is all the same as where you (one?) particularly live and ride.
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Re: Evaluating the impact of cycle helmet use...

Postby Steady rider » 12 Jul 2020, 9:04pm

The utility cyclist wrote:
All helmet wearers and those that push for people to wear them whilst cycling do massive harm to society as a whole never mind other people riding bikes helmeted or not. That's not opinion, it's a fact.


Evaluation of Australia's bicycle helmet laws, The Sports Science Summit, O2 venue London UK http://www.cycle-helmets.com/au-assessment-2015.pdf Presented 14 January 2015.

Page 40
Erke and Elvik 2007 208 examined research from Australia and New Zealand and stated:
"There is evidence of increased accident risk per cycling-km for cyclists wearing a helmet. In Australia and
New Zealand, the increase is estimated to be around 14 per cent."


Conclusions - part states;
This evaluation of the Australian cycle helmet laws finds they have seriously failed in many ways.
'Australia's helmet law disaster'184 sums up the outcome. The safety aspects of cycle helmets were
overestimated and the negative health consequences of introducing legislation and discouraging cycling were
not properly assessed. The actual risk of serious head injury when cycling is low. The societal health cost
factor against the laws is calculated at 109, indicating they cause considerable harm.


Helmet laws mainly only come in when reasonable levels of wearing occur in the general population. Those wearing helmets indirectly contribute to calls for legislation, that according to research has resulted in massive harm, with a calculated value of 109 against the law in one example. In addition there is the accident compensation side, where compensation is sometimes reduced for not wearing a helmet.

Helmet wearers and those promoting helmet legislation can have an effect and result in social damage, even if their intentions were to promote safety.

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Re: Evaluating the impact of cycle helmet use...

Postby Jdsk » 12 Jul 2020, 9:08pm

Steady rider wrote:Helmet laws mainly only come in when reasonable levels of wearing occur in the general population. Those wearing helmets indirectly contribute to calls for legislation, that according to research has resulted in massive harm, with a calculated value of 109 against the law in one example.

What does "109" mean, please?

Have you got a reference for that research, please?

Thanks

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Re: Evaluating the impact of cycle helmet use...

Postby Steady rider » 12 Jul 2020, 9:32pm

http://www.cycle-helmets.com/au-assessment-2015.pdf

https://www.researchgate.net/publicatio ... elmet_laws
page 28
Cost effectiveness
Piet de Jong in 2012 provided a way to evaluate the question whether mandatory bicycle helmet laws deliver a net societal health benefit158. He reported that "in jurisdictions where cycling is relatively unsafe, helmets will do little to make it safer and a helmet law, under relatively extreme assumptions, may make a small positive contribution to net societal health." From the information available, an estimate can be made for Australia. The formula for the cost benefit ratio is (mu x beta)/(e x q ), where:
mu = odds of cycling is not maintained
beta = health benefit of cycling
e = proportional reduction in head injuries
q = proportion of accidents involving the head
The Handbook of Road Safety Measures159 detailed its findings on 'Effects on injuries of mandatory wearing of bicycle helmets' with:
• Increased use of helmets, Head injuries -25 (-30; -19)
• Increased risk per km cycled, All injuries +14 (+10; +17)
• Less cycling, All injuries -29 (-30; -28)
• Net effect, All injuries -22 (-23; -21)
Assuming values of 29% discouraged as reported, assuming 20 to 1 for health factor, e = - 0.25 as reported and q =0.3 matching general data (Whately 1985). mu value is 0.408, using 0.29/1-0.29 = 0.29/0.71= 0.408 beta = 20 e = 0.25 q = 0.3
Cost benefit ratio is (0.408 x 20)/(0.25 x 0.3) = 8.16/0.075 =109


The calculation was based on estimates of the health benefits of cycling and reported data. Professor Piet de Jong in 2012. ref 158 provided a formula to take account of the significant variables. The end result shows the outcome was a major negative health effect by discouraging cycling.

more recent research shows the increased accident rate may be higher than the 14% calculated in 2007.

https://www.researchgate.net/publicatio ... jury_rates

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Re: Evaluating the impact of cycle helmet use...

Postby Jdsk » 13 Jul 2020, 9:49am


Thank you

(They're both by Coiin Clarke.)

Jonathan

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Re: Evaluating the impact of cycle helmet use...

Postby Jdsk » 13 Jul 2020, 9:55am

Vorpal wrote:[Elvik found no overall benefit in the use of helmets. When he looked at Anderson's(?) review, he found some benefit in older studies that gradually decreased over time, and theorised that helmets used to provide some small benefit that has decreased with newer design and emphasis on cooling and weight.

From Elvik 2013:

"For all studies, based on a random-effects model adjusted for publication bias, the best estimate is a 33% reduction of the risk of injury to the head, the face or the neck if a bicycle helmet is worn. This summary estimate is statistically significant at the 5% level."

As I've said above this is very very difficult, and once you start diving into subgroups it gets even harder. But "no overall benefit" is too strong for what Elvik says.

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Re: Evaluating the impact of cycle helmet use...

Postby Vorpal » 13 Jul 2020, 10:01am

Jdsk wrote:
Vorpal wrote:[Elvik found no overall benefit in the use of helmets. When he looked at Anderson's(?) review, he found some benefit in older studies that gradually decreased over time, and theorised that helmets used to provide some small benefit that has decreased with newer design and emphasis on cooling and weight.

From Elvik 2013:

"For all studies, based on a random-effects model adjusted for publication bias, the best estimate is a 33% reduction of the risk of injury to the head, the face or the neck if a bicycle helmet is worn. This summary estimate is statistically significant at the 5% level."

As I've said above this is very very difficult, and once you start diving into subgroups it gets even harder. But "no overall benefit" is too strong for what Elvik says.

Jonathan

I apparently misremembered that study, but this is question he has looked at a number of times, and I have read his other studies... I guess they kind of blend together. He has another one is which he found roughly 25% reduction, but also a slight increase in neck injuries. And another is which he found no overall benefit. He does favour helmets, especially for children, which is a reason that the conclusion surprised me, but I must have misremembered which study it was in. Apologies, but I do not have time right now to figur our which one it was. If/when I do, I will come back to this.
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Re: Evaluating the impact of cycle helmet use...

Postby mikeymo » 13 Jul 2020, 2:39pm

Vorpal wrote: however, as I do think that focus on the topic has harmed cycle campaigning.


It seems to me that "focus on the topic" originates from those whose opinion is that helmets haven't been proved to save lives, in "whole population studies".

I don't think most helmet wearers are at all "focussed" on it. They put a helmet on, then cycle somewhere.

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Re: Evaluating the impact of cycle helmet use...

Postby pjclinch » 13 Jul 2020, 2:44pm

Part of the problem is that good science is reproducible, and one thing you find looking through all the stuff that shows a benefit is that the degree of benefit is actually all over the place, from quite low to 85% (actually the best benefit in a peer reviewed paper I've seen was 180%, noted as 60% in the paper but a reader pointed out the authors (Cook and Sheikh IIRC) hadn't followed their methodology correctly and had failed to include a multiplier of 3, their response was to thank the correspondent for pointing out the error which they admitted to making, but saying that the overall conclusion of a benefit was what was mattered). This is a lot of why I really don't find it trustworthy.

There should be a methodology most people are happy with which when applied gives you reproducible answers. I haven't seen any such thing in the decade or so I was looking hard, and in the decade since when I've kept in touch with the subject but in less detail there haven't been any noises that any such thing has appeared. Looking briefly in to ones that make the most noise (e.g., Olivier's work), they don't seem to have got past the usual confounders.

Population studies have a different set of problems, notably that the data sets are so coarse it's difficult to conclude much beyond getting everyone to wear helmets doesn't seem to help much at a level of overall public health. That is a useful conclusion in itself, but is no use at all at the level of do I benefit from wearing a helmet. Population studies tell us about Average Cyclists doing Average Journeys, and of course neither really exists, and all studies are only really concerned with benefits at serious injury or death level which is actually beyond what they're meant to do. If you want to wear one so your head isn't grazed by low branches MTBing through woods there really isn't anything in the literature for you.

The reason I often cite the Goldacre/Spiegelhalter editorial rather than particular peer reviewed studies is because it chimes very well with what I found myself looking at said studies. I found they don't tell you much beyond the fact that there hasn't been much to tell. G&S say it doesn't tell you much. If an evidence geek like Goldacre cites cycle helmets as quite specifically being a great case study in showing problems for epidemiology then maybe there really are problems...

In the meantime, I will say that the best description I've heard of helmet effectiveness is "about zero, plus or minus error bars", with a note that the error bars may be quite large. Anyone saying as a general case that people should or shouldn't wear them is going well beyond the clear evidence. In the meantime, pick or choose according to your own contexts.

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Re: Evaluating the impact of cycle helmet use...

Postby mikeymo » 13 Jul 2020, 2:46pm

pjclinch wrote:
The utility cyclist wrote:All helmet wearers and those that push for people to wear them whilst cycling do massive harm to society as a whole never mind other people riding bikes helmeted or not. That's not opinion, it's a fact.


All helmet wearers do massive harm to society as a whole? Really?

Okay, pop quiz, how does...

...do "massive harm to society"?

There's nothing quite like wildly overstating your case to put people right off listening to your actual valid points.


Though to be fair, there's one thing that Danny MacAskill sort of demonstrates. Which is that, given how many falls he's had, it might not be cyclist-falling-off-bike that is dangerous. But car-colliding-with-cyclist that is dangerous.