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It can't happen here
I was browsing he
http://www.magma.ca/~ocbc/hfaq.html When I clicked on this link: http://www.magma.ca/~ocbc/jpeds.html For convenience, I've copied the text below. At first, I wondered if it was a hoax, but it seems to be authentic--the spelling and language are not unusual for such cross-cultural papers. Tatsuhiro Yamanaka does appear to be a published Japanese pediatric researcher. For those not familiar with statistics, the numbers do support the conclusion of no significant difference for such a study. (When an odds-ratio is 95% likely to fall on either side of 1.00, it means that that the figures, no matter how they may appear at first glance, suggest a 95% probability that an effect was either positive, negative, or dead even.) An alternative thread title was "Won't someone think of the children?" Cheers, Carl Fogel THE EFFECTIVENESS OF WEARING PEDESTRIAN HELMET WHILE WALKING FROM HOME TO SCHOOL IN ELEMENTARY SCHOOL CHILDREN. (from the Third International Conference on Injury Control and Prevention, Melbourne, Australia, February 1996) Presenter: Tatsuhiro Yamanaka, JAPAN Author(s): Yamanaka Tatsuhiro; Ogihara Arata Department of Pediatrics, Yaizu Municipal Hospital, Yaizu city, Shizuoka, Department of Public Health, School of Medicine, Yokohama City University, Yokohama city, Kanagawa, JAPAN. PURPOSE: To evaluate the effectiveness of head injury prevention among pedestrians wearing a helmet while walk. METHOD: We performed a retrospective case control study of head injury in elementary school children over a five-year period in Shimizu city. Population is 240, 000 and there are 26 elementary schools in this city. The principle of the school can decide whether helmet wearing should be a rule for pupils, which means there are only two possible situations, wearing or not wearing a helmet while walking. Elementary school children are prohibited from bicycling to school and there is no school bus system at all. The number of head injuries and other injuries were collected from the data sheet by the insurance system of the School Safety Division of the National Stadium and School Health Center of Japan. RESULTS: There were 13 elementary schools which required students to wear a helmet while walk. One school had changed from wearing a helmet to not wearing a helmet during the 5-year period. The accumulated annual number of elementary school children was 32,922 required to wear helmets, and 56,214 not required to wear helmets. The number of injuries among children wearing helmets was 58 (0.18%), and 125 (0.22%) among children not wearing helmets during the 5-year period. Head injuries were recorded in 4 children (0.012%) wearing helmets and 10 (0.018%) who were not wearing helmets. CONCLUSION: There was no significant difference between children wearing helmets and those not wearing helmets in the incidence of all injuries and head injuries by Xy test. The odds ratio for the no helmet system was 1.26 ( 0.92 to 1.71 for 95 % confidence) for all injuries and 1.46 ( 0.45 to 4.12 for 95 % confidence) for head injuries. |
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#2
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It can't happen here
You really have to question the method of the study. I happen to live
in the Yokohama area where the local high schools require the bike riding students to wear helmets. I see them every morning with their standard white plastic bucket helmet--in their bike basket! Maybe one out of ten actually has one on their head. I have to wonder if the elementary kids acted similarly. |
#4
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It can't happen here
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#5
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It can't happen here
In article .com,
"tiborg" wrote: You really have to question the method of the study. I happen to live in the Yokohama area where the local high schools require the bike riding students to wear helmets. I see them every morning with their standard white plastic bucket helmet--in their bike basket! Maybe one out of ten actually has one on their head. I have to wonder if the elementary kids acted similarly. Well, what they did is a pretty standard epidemiological approach. However, it is not at all clear that they controlled for confounds such as- which you mention- compliance with wearing the helmets or behavioral changes while wearing the helmets. Had they gone and sampled the compliance data, then their information would be more meaningful. Perhaps only 10% of the children wore their helmets when out of sight of parents or teachers; that might account for the lack of statistically significant difference. On the other hand, if there was 100% compliance then the lack of significant difference would suggest that the helmets the kids are wearing are of little protective utility. It's ironic that the prevalence rate of head injuries is so low even in the unprotected group and yet this is such a big deal, while the hazards of smoking, sedentariness and poor diet and such have huge effect sizes but little is done about those. Are the school principals ordering students to eat a balanced diet, get 30 minutes of aerobic exercise per day and to not smoke? |
#6
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It can't happen here
Tim McNamara wrote: Well, what they did is a pretty standard epidemiological approach. However, it is not at all clear that they controlled for confounds such as You forgot the most important confound, in this wretched system where children are forbidden to ride bicycles to school and must wear helmets while walking to school. The source of head injury is children banging their heads against the wall over the outrageous stupidity of the adults. Usually they keep it to a mournful knock, but sometimes it just gets out of control. |
#7
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It can't happen here
In article . com,
"41" wrote: Tim McNamara wrote: Well, what they did is a pretty standard epidemiological approach. However, it is not at all clear that they controlled for confounds such as You forgot the most important confound, in this wretched system where children are forbidden to ride bicycles to school and must wear helmets while walking to school. The source of head injury is children banging their heads against the wall over the outrageous stupidity of the adults. Usually they keep it to a mournful knock, but sometimes it just gets out of control. You're right, I overlooked that one. |
#8
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It can't happen here
Tim McNamara wrote:
It's ironic that the prevalence rate of head injuries is so low even in the unprotected group and yet this is such a big deal, while the hazards of smoking, sedentariness and poor diet and such have huge effect sizes but little is done about those. But people don't want to be let off the hook for being nonsmokers or healthy eaters. They want to be let off the hook for using wasteful, unhealthy forms of personal transportation. Lots of folks know that cycling for transportation is the right thing to do, and that they have no good excuse for not doing it. Pushing helmets for cycling makes cycling seem like a risky thing to do. That gives them a psychologically acceptable justification for not doing it. It's no wonder that cycle helmets are an attractive idea to many non-cyclists, especially if they also happen to be busybodies. What I don't understand is why so many cyclists buy into a trend that is pretty clearly contrary to their collective interests. Wearing a helmet makes a tacit statement to non-cyclists. The cumulative risk-elevating effects of that statement may be a lot more potent than the cumulative protective effects of the helmets that help make it. Riders who wear helmets and other conspicuously bike-specific gear may think they are saying something like "I am a serious, skillful, and responsible rider who is worthy of your respect." What a non-cyclist is likely to hear, though, is more like "I get around by a means that is so dangerous that I have to wear a crash helmet-- like a skydiver, a race car driver, or a spastic. I must be crazy! You are very wise to drive your nice safe comfortable car and not be a foolhardy, queerly clothed masochist like me." I think the consequences of spreading the latter perception represents a lot more potential harm to us that the benefit conferred by bike helmets. Chalo |
#9
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It can't happen here
Chalo wrote: What I don't understand is why so many cyclists buy into a trend that is pretty clearly contrary to their collective interests. Wearing a helmet makes a tacit statement to non-cyclists. The cumulative risk-elevating effects of that statement may be a lot more potent than the cumulative protective effects of the helmets that help make it. Riders who wear helmets and other conspicuously bike-specific gear may think they are saying something like "I am a serious, skillful, and responsible rider who is worthy of your respect." What a non-cyclist is likely to hear, though, is more like "I get around by a means that is so dangerous that I have to wear a crash helmet-- like a skydiver, a race car driver, or a spastic. I must be crazy! You are very wise to drive your nice safe comfortable car and not be a foolhardy, queerly clothed masochist like me." I think the consequences of spreading the latter perception represents a lot more potential harm to us that the benefit conferred by bike helmets. I agree. But I think it's going to be a long, long time before many other cycling enthusiasts understand this point, let alone accept it. One problem is that most avid American cyclists today have never seen a magazine photo of an avid cyclist who was not under styrofoam. _Bicycling_ magazine, _Adventure Cycling_ magazine, and the League of American Bicyclists' magazine have long had policies against showing American folks biking without helmets. (They give dispensation to "ignorant" people in Europe or the Third World.) Consequently, most avid American cyclists literally never consider riding without a helmet. Another problem is the inborn human tendency to use dress to indicate their "tribe." This seems to be universal, and psychologically important. It leads to some bizarre looks - like tribes with weirdly modified bodies and really shocking costumes. I'm talking, of course, about tribes that do things like shave the hair off their legs, and wear day-glo magic symbols of their favorite corporations on their cycling jerseys. ;-) But worst is the real conviction of many, perhaps most, cyclists that what they are doing _is_ actually dangerous! AFAICT, neither swimmers, skiers, boaters, skaters, general aviation pilots, motorcyclists, nor avid motorists are as likely to enthusiastically accept the idea that what they do is very dangerous. It seems far easier to google links to bike helmets and bike head injury than it is to, say, drownings and water wings! (Guess which would _really_ save more lives per year.) Overall, you're correct. Cyclists are excellent at shooting themselves in the foot. Perhaps we should have bullet-proof cycling shoes. After all, if only _one_ toe can be saved...! - Frank Krygowski |
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