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#71
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published helmet research - not troll
S o r n i wrote: Mark & Steven Bornfeld DDS wrote: JT, I'm really flattered that you consider me a master of anything--that's high praise indeed! Hard to consider your positions when you can't even fix your user name. Bill "multiple personalities? OK then" S. Name's Steve Bornfeld. I sometimes post from my home computer, and sometimes at the office. Steve |
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#72
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published helmet research - not troll
Just zis Guy, you know? wrote: On Sat, 19 Jun 2004 10:59:23 -0400, Mark & Steven Bornfeld DDS wrote in message : I posted the link of a review of previously published clinical studies. That'll be where you went wrong, then. Epidemiological studies based on whole population data (including series where there are substantial step-changes in helmet use over very short periods, like in Australia) show no discernible benefit. Small-scale prospective studies show benefit, but often fall apart under investigation due to basic errors. Injury Prevention has just published a critique of one such paper by Cook & Sheikh; they mistook percentages for percentage points (a fairly basic statistical error) - if you correct this they are saying that helmets are 186% effective, with every helmet protecting not only its wearer but somebody else as well - this clearly demonstrates that there are major confounding factors in the data for which they have not accounted. Let me see if I get this straight. All the studies showing a benefit have fatal flaws; all the studies that show no benefit are well-designed. The studies I saw cited are all retrospective studies. I believe it is possible that somewhere a paper may have been published that confuses percentages for percentage points. It is hard to believe this happened multiple times in referreed journals. Let me be clear--I am not an expert in safety data nor in epidemiology. But I am up to my eyeballs in newsgroup pundits (in unrelated fields) making patently ridiculous claims about the body of evidence in fields in which I do have expertise. It is impossible for me to evaluate helmet data for myself, nor have I found it prudent to believe folks such as yourself who may very well have that expertise. One hopes that people in position of authority choose carefully in whom they listen to when policy is made. Many of the clinical papers are actually just literature reviews, with remarkably few actual studies, of which the best-known is Thompson, Rivara and Thompson's 1989 paper in the New England Journal of Medicine. The flaws in that study are well-documented (it arrives at a figure of 85% effectiveness by comparing poor solo urban street cyclists with middle-class families on bike paths and attributes the entire difference in injury rates to differences in helmet use). See, I'm going to have to look up that paper. It is very, very difficult for me to believe that NEJM would publish a paper with a flaw that blatant. It is still quoted as gospel by almost every "new" paper and literature review, and I have only once or twice seen any explicit mention of the known flaws in the study. In fact, if you replace the "control" group with Rivara's own street counts from the previous year, the supposed benefit vanishes. BHSI still quote it, despite knowing that it is wrong, because the figure is "so ingrained in the injury prevention community" that to use another figure would be "unhelpful". Unhelpful to whom? Those seeking to make the case for compulsion? Or those seeking to form a balanced judgement based on theevidence? By the way, according to BHSI this thread is not happening ;-) The fact that head injury rates have risen by 40% in the USA in a period when helmet use rose from 18% to 50% surely tells us something. Are we talking about cycling head injuries, or total head injuries? As does the fact that the pro-helmet British government has admitted that it knows of no case where cyclist safety has improved with increasing helmet use. I'd love to hear some context. It is certainly understandable to me that racers who'd become accustomed to the wind in their hair would object to the "intrusion" of the insurance companies. Certainly there had been no studies back then demonstrating the uselessness of helmets in preventing serious injuries, but those I spoke to (some of whom you undoubtedly know personally) were just as opposed to mandated helmets as you are now. That was not, in my opinion, an actuarial judgement; there was not enough data to go on at the time. Quite why a device designed for a crash at around 12mph should be mandated for racing is an interesting philosophical question. Actually in this area you have a point. It was a decision made for the USCF by whichever insurance carrier was willing to write the liability policy. Far be it from me to tell you their decisions are made on the basis of good, rational data. ;-) HPV races now have helmets mandated. I have never seen an HPV racer sustain a head injury in a crash. Several helmeted wedgie racers have died and been brain injured in recent times, though. Krygowski (and perhaps you) can probably name some safety measures that you would acknowledge will decrease death and morbidity from bicycle accidents. Only about 10% of cyclist injuries are to the area covered by the helmet and many (possibly most) cyclists who die of head injury also have other mortal injuries. Most fatal cyclist injuries are of course sustained in crashes involving motor vehicles: it is motor traffic, not cycling, which is dangerous. Statistically you are right of course. But we are talking about cycling; we might have much more to talk about were this a political or automotive ng. But I know of several folks who have suffered head injury, a couple of which were life-threatening (prolonged coma and permanent neurological damage) without the benefit of motor vehicles. Any "safety programme" which ignores these fundamental facts is necessarily going to be of limited effect. The first, best thing that can be done to improve cyclist safety is to promote cycling. There is robust evidence from around the world that risk falls as participation increases, for a variety of reasons. The best thing a cyclist can do to ensure their own safety is to ride confidently and in a vehiclular style, as per Effective Cycling (and the equivalents in other countries such as Cyclecraft). If you look at detailed returns on crashes you find recurrent themes: cyclist injured by turning goods vehicle after the cyclist has gone up the inside at a junction; cyclist hit by car emerging from junction (which can be reduced by riding further out so you are where the driver is looking); cyclist hit by overtaking car which turns across their path (which can be reduced by riding further out, as the overtaking manoeuvre is then more deliberate and reminds the driver that you are there, rather than simply cruising by). And of course a cyclist should ensure that their bike is well maintained, with brakes and steering in good order. The biggest problem with helmet promotion is that it reinforces the perception of cycling as dangeorus without teaching any of the techniques which reduce the danger. In doing so, it actively deters cycling, which paradoxically /increases/ risk. Clarification please: are you talking about relative risk to the rider, or total risk to the population? Now, I would not normally care too much about people who decide to promote helmet use, if it weren't for the studies which show that it deters cycling - but these days the only thing stopping some jurisdictions from passing a helmet law is low levels of helmet use. More than one Government has said that compulsion will be introduced when voluntary wearing rates are high enough (at least they've learned that much from Australia, where cycling was decimated by compulsion). So the Liddites I must complement you on this usage! have persuaded Gvernments that every person who wears a helmet is voting for compulsion. That is unacceptable. My objections to helmet compulsion are not libertarian, but evidence-based. We have the experience of laws in Australia, New Zealand and Canada to draw on. In no case did injury rates reduce. In every case cycling was deterred. As long as this is not libertarian, and allowing that proper bicycle maintenance and effective cycling are more important to cyclist safety, what would your feelings be about: 1) Mandatory licensing of cyclists (as per motor vehicles) 2) Mandatory minimum age for cyclists on public streets and roads 3) Mandatory registration of bicycles and periodic bicycle inspections But of course, these are unwelcome messages. When you compare child head injury rates for road crashes you find that pedestrians and cyclists have around the same proportion of head injuries, and pedestrian injuries are much more numerous (the risk levels in off-road cycling for children are an order of magnitude lower). Any justification of cycle helmet promotion applies to a much greater extent to walking helmets. And even more so for car occupants, whose fatality rate from head injuries is much greater. Another clarification please: The head injury rates for cyclists vs. pedestrians vs. auto passengers are for 1) Mile traveled 2)total number in population 3) hour spent in activity What to do? Clearly the answer is to reduce the danger which cars pose to other road users, but that is politically unacceptable. Cycle helmets give the impression of "doing something" without the need to offend the motor lobby, which is politically very attractive. I think that making the auto industry the focus in this discussion in very much the same way makes it too easy to absolve ourselves of responsibility in this issue. I certainly agree with you about the relative danger of autos. I also agree that doing anything meaningful in this area will be difficult (although the increase in the price of crude oil is doing more than the political will would allow--if a sustained rise in gasoline prices leads to diminished sale of SUVs, I would be very happy). But if we wish to appear to be "doing something", it is not enough to fault those who think helmet laws will save us; we must have the courage (and the political clout) to do something that WILL be meaningful. Best, Steve 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 |
#73
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published helmet research - not troll
Frank Krygowski wrote: Mark & Steven Bornfeld DDS wrote: Krygowski (and perhaps you) can probably name some safety measures that you would acknowledge will decrease death and morbidity from bicycle accidents. Are there any that you would mandate? Or is this more about personal freedom than safety? Personally, I heartily agree with many already-mandated safety measures. Examples are obedience to traffic signs and signals. Respecting right of way, and other similar traffic laws. Use of lights at night. There are some I disagree with. For example, many states require a bicycle bell. To me, this is senseless - it adds nothing practical to safety. IOW, it's a mistake to paint me as a libertarian, as you did in another post. Having said that, I _do_ think personal freedom is very important. If you disagree, post your diet for the past month, and we'll get started on what, and how much, you should be allowed to eat! Hey--my diet shouldn't concern you--only my wife and daughter who have to smell me. Steve |
#74
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published helmet research - not troll
In article TQJAc.135474$Ly.96010@attbi_s01, "Shayne Wissler"
wrote: "John Forrest Tomlinson" wrote in message ... Now what evidence do you have about helmets protecting against dented skulls or brain injuries? I have an idea for an experiment. Go outside and have someone hold a brick about 2 feet over your bare head and have him drop it. Observe the pain and damage (assuming you're still conscious). Then try the same experiment on your friend, but have him wear a cycling helmet. I Dayum, Shane! No one ever came up with this before! If you are unable to apply the knowledge gained from this experiment to real-life, I would submit that it's not more experiments that you're actually in need of. Dayum, Shane! No one ever thought of this clever insult before! Shayne Wissler I can't believe you left out the part about "If you don't wear a helmet, you have no brains to protect." How could you resist putting the cherry on top of your sarcasm sundae? -- Stella Hackell She who succeeds in gaining the mastery of the bicycle will gain the mastery of life. --Frances E. Willard, _How I Learned to Ride the Bicycle_ |
#75
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published helmet research - not troll
"Frank Krygowski" wrote
Like the vast, overwhelming majority of cyclists throughout history, I've escaped serious injury perfectly, both as an adult (30+ years) or as a kid (about 20 years). The same is true of my wife, and our now-grown kids. And until helmets became a commercial item, this was known to be normal. Now we're faced with fear mongering. I am pleased to have some uphold reason about bicycle safety. When I started riding bicycles (It was in 1948.), no one had ever heard of using a helmet on a bicycle. And all kids had bicycles and rode them everywhere. My brother and I delivered newspapers every morning on them. And in the dark in the winter. I don't remember my parents, or anyone else, expressing concern about safety. I have been riding ever since and have never gotten hurt. And rode a little over 5,000 miles last year. Today, I see only two types of riders. Grownups with time and money who ride for exercise and sport. And Hispanic men going to and from work. No kids. In fact, the government or someone is pushing something called a "Safe Routes to School" program which never seems to be funded. But the clear and loud message from this title is, if I can over-state a little, "Don't let your kids ride their bicycle to school. It is not safe. Wait until we can put in bike paths that are separate from the dangerous roads." Again, thanks to Frank for his tireless defense of reason. |
#76
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published helmet research - not troll
"VC" wrote in message om... "Shayne Wissler" wrote in message news:TQJAc.135474$Ly.96010@attbi_s01... snip of implication that helmets may increase risk of rotational brain injury Not everything is what it seems to be. A helmet may indeed not be so good for your health. Nice imagination, but do you have any actual reason to believe that helmets increase the rotational forces involved? Casual observation would imply the opposite. Helmets are more slippery than skin, and they have a larger radius than the skull. Also, the helmet is not as tightly coupled to the head as the skin is, and if the helmet got a large impulse of rotational force from a localized postion on the helmet, it would tend to be ripped apart, damping the force. All of thse would tend to reduce the rotational forces involved. What reason do you have to think that the opposite would happen? Shayne Wissler |
#77
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published helmet research - not troll
"Stella Hackell" wrote in message ... Dayum, Shane! No one ever came up with this before! snip Dayum, Shane! No one ever thought of this clever insult before! snip Gee, I guess when someone had thought of something before, then it must not be worth saying, eh? How could you resist putting the cherry on top of your sarcasm sundae? Evidently, your hill-billy expressions above match your metaphorical wit. Shayne Wissler |
#78
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published helmet research - not troll
Shayne Wissler wrote: "VC" wrote in message om... "Shayne Wissler" wrote in message news:TQJAc.135474$Ly.96010@attbi_s01... snip of implication that helmets may increase risk of rotational brain injury Not everything is what it seems to be. A helmet may indeed not be so good for your health. Nice imagination, but do you have any actual reason to believe that helmets increase the rotational forces involved? Casual observation would imply the opposite. Helmets are more slippery than skin, and they have a larger radius than the skull. Also, the helmet is not as tightly coupled to the head as the skin is, and if the helmet got a large impulse of rotational force from a localized postion on the helmet, it would tend to be ripped apart, damping the force. All of thse would tend to reduce the rotational forces involved. What reason do you have to think that the opposite would happen? Shayne Wissler This is probably harder to demonstrate. That's why the standard is designed for a direct blow. The problem (inexact as my understanding may be) is that there need not be rotation of the skull to induce rotational forces on the brain. A tangential blow might very well do the same. IMO this is not a reason to discount the efficacy of helmets, but it does point out the difficulty of predicting real-life implications for a given traumatic event. Steve |
#79
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published helmet research - not troll
Steven Bornfeld wrote:
S o r n i wrote: Mark & Steven Bornfeld DDS wrote: JT, I'm really flattered that you consider me a master of anything--that's high praise indeed! Hard to consider your positions when you can't even fix your user name. Bill "multiple personalities? OK then" S. Name's Steve Bornfeld. I sometimes post from my home computer, and sometimes at the office. Still takes about 13 seconds to change your Usenet account info. Bill "nothing to do with what computer you're on" S. |
#80
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published helmet research - not troll
In article ,
Steven Bornfeld writes: As long as this is not libertarian, and allowing that proper bicycle maintenance and effective cycling are more important to cyclist safety, what would your feelings be about: 1) Mandatory licensing of cyclists (as per motor vehicles) 2) Mandatory minimum age for cyclists on public streets and roads 3) Mandatory registration of bicycles and periodic bicycle inspections Aw, bloody hell. At least stick to one agendum at a time, please. -- -- Powered by FreeBSD Above address is just a spam midden. I'm really at: tkeats [curlicue] vcn [point] bc [point] ca |
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