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Charlie Lloyd, spokesperson London Cycling Campaign
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In the BMJ editorial (BMJ 2000;321:1035-1036) "Bicycle helmets: it's time to use them " Rivara, Thompson and Thompson say that "public policy makers have a duty to promote the health of the public and to base their recommendations on evidence of effectiveness". The paper by Cook and Sheikh offers anything but strong evidence of the efficacy of cycle helmet wearing. Cook and Sheikh suggest that an unspecified increase in helmet wearing caused a reduction in the proportion of head injuries among cyclist casualties between 1991 and 1995. At first glance the published figures for cyclist fatalities (DETR, Transport Statistics Great Britain, 1997) show a similar trend with a significant fall compared to the average for the previous five years. However over the same period pedestrian fatalities fell at a slightly faster rate. In the two subsequent years cyclist fatalities rose to be above the average of the previous four years (by 6.5% and 1%) while pedestrian fatalities continued to fall. It is difficult to theorise any causation of helmet wearing activity for these outcomes. Public policy makers should also look at the type of collisions that cause these fatalities. For example in London the majority of cyclists' deaths result from collisions with Large Goods Vehicles (11 out of 12 deaths in 1998). Cycle helmets offer no protection against the type of crushing injuries routinely recorded as the cause of death in these cases. Most of the 804 of British cyclists' death in 1991 to 1994 occurred before hospital admission and so are not included in the type of study conducted by Cook and Sheikh. A comparison of Britain and similar European countries where cyclist fatality and injury rates are many times lower and fewer helmets are worn should suggest to policy makers that action to prevent collisions by making the roads safer would be far more effective than rules to enforce helmet wearing. Charlie Lloyd
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Tom Godefrooij Dutch Cyclists' Union 'Fietsersbond'
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Whereas one could claim that the paper of Cook and Sheikh are presenting facts, the editorial based on this paper is biased if not narrow-minded. My main objections against the editorial conclusions are threefold: 1. In fact the objections of many cyclists' organisations have not to do
so much with the question wheather or not a helmet is effective in reducing
the risk of head-injury. It is much more about a side-effect of helmet-
legislation and helmet-promotion: its impact on the level of bicycle use.
2. I cannot understand why the helmet debate is so exclusively a debate about cycling. Head-injuries occur to all road-users. It would only be logical if the debate of helmet wearing should be extended to car drivers and pedestrains as well. There is no evidence that cyclists have a disproportinal risc of head injury in comparison with other road users. 3. The helmet debate is diverting the attention from the policies which could be much more effective in increasing cyclists' safety. It is illustrative that the helmets debate is most fierce in those countries where cyclists have little rights and facilities. Traffic calming and good bicycle infrastructure are much more effective when it comes to prevent casualties and injuries (including headinjuries). Apart from this I support the comment of Avery Burdett on the absence of information on prevailing rates of head injuries amongst other road users, and his reference to Bruce Robinson. But as stated above, the relevance of this debate is only marginal, because it is not addressing the key issue: the balance between positive and negative effects of helmet promotion and legislation. |
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Nigel Perry, Senior Lecturer Massey University, New Zealand
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Poor science and cycle helmet advocacy seem to be common bedfellows. It is a pity we are now seeing it in the BMJ. Cook and Sheikh's paper is certainly poor science. Their proposition is "we observe A and conclude B", yet they show no correlation between A and B! How many other factors could there be? Did cyclist numbers, trips, distances travelled stay the same? Where there any road safety programmes run over this period? What was the trend in injury rates for other classes of road user? Etc. Whether the observation is correct or not is certainly not answered by this paper. Yet the conclusion is then supported in Thompson, Thompson and Rivera's Editorial. It must be acknowledged that these three are among the world's leading cycle helmet advocates. Their seminal 1989 paper is probably the most oft quoted in support of helmet promotion and mandation, and indeed Cook & Sheikh do so. However this paper has also been shown to be flawed by Robinson making its conclusions unreliable, more poor science. Thompson, Thompson & Rivara's dismissal of the large body of evidence which indicates that cycle helmet manadation has been somewhat less than successful, if improving safety and health rather than helmet sales is the goal, is inexplicable. Risk homeostasis? Of course it occurs - "he can't do it as he isn't wearing a helmet", on kid to the group as they challenge each other to ride down a steep obstacle strewn bank in NZ. One story of course doesn't prove a trend, just like those that say "my helmet saved my life", but to deny the existence of risk compensation is incredible. Helmets of course offer some protection, but they have their design limits. To imply, as seems to be the norm during helmet promotion, that they offer significant protection from the type of severe head injuries caused by vehicular impact verges on the criminal. However Tom Godefrooij in his repsonse "Helmet debate is counter productive" is right, this debate should long since have been abandoned. Even if cycle helmets and mandation provide some benefit, which is clearly questionable, we are today faced with the undisputed fact that cyclists in countries such as The Netherlands and Denmark, where helmets are rare, are safer than those in New Zealand and Australia, where helmets have been mandated for years. Helmets are clearly the wrong solution. Over the period 90-98 cycling in New Zealand dropped by 19%, we can only wonder how much better off we would be today if instead of deciding cycling was dangerous and mandating helmets the NZ Government had instead promoted cycling and road safety measures. Tom Godefrooij's comments on helmets for car occupants also point out a huge inconsistency in most cycle helmet advocates arguments. That helmets for car occupants make "as much sense" as for cyclists has long been suggested by a number of researchers. FORS in Australia published a report claiming A$500Million would be saved if car occupants wore "cycle" helmets or padded headbands, reducing to just A$350Million if the car fleet was completely equipped with airbags. Some cycle helmet advocates do wear helmets in their cars as well, and however much we might disagree with their overall conclusions on the need for helmets, we cannot help but respect them for their consistency. What is baffling is that those who find a risk unacceptable when taken by a cyclist, and call for helmet mandation, find the same risk acceptable for motor vehicle occupants - to the extent that they choose not to even protect their own heads! It is hard to give credence to any argument based on such an inconsistency. In New Zealand we have the perverse situation that car borne Police Officers, unhelmetted of course, stop and ticket unhelmetted cyclists for being "irresponsible" and taking an "unacceptable risk". Mandated hypocrisy is no basis for a sound helath and saftey strategy; yet Thompson, Thompson and Rivara appear to want to see this situation expanded to other countries. It is time poor science and scapegoating were removed from cyclist safety. Don't follow New Zealand, we got it very wrong and some of us are truely ashamed. |
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Peter Ward, GP trainee Newcastle u Tyne
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After Rivara, Thompson and Thompsons' editorial on cycle helmets and Cook and Sheikhs' conclusive paper on how brilliantly they work, I believe there is only one course of action open to us if we want to be called civilized countries. We must immediatley start a case controlled trial to see if helmets can reduce the huge amount of pedestrians killed by head injuries. If they do (are there any doubters?) we can then lobby the governments of the World for a 'helmet law' thus saving millions of lives. We could ask the police force, who in Britain mostly wear them already to fine anyone walking the streets without one and divert lots of money from catching speeding car drivers into this. Of course we will have to exempt car drivers as they are a very strong lobby and it may be politically difficult to include them. This would have the effect of persuading people to drive about in their cars more so making the streets safer...errm, wouldn't it? |
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Richard Ayres
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Editor - Recently in our town a cyclist was killed by a large lorry who's driver failed to see him while turning left. In the local newspaper it was briefly noted that the wheels of the lorry went over the mans chest, but the final disparaging comment was; "and he was not wearing a cycle helmet"! Do-gooders such as Rivara and Thompson (1)are no doubt well meaning in their assertion that we should all wear cycle helmets, but wrong to assert that the evidence is overwhelming. The case-control study by Cook and Sheikh (2) suggests that head injuries as a proportion of total cycling injuries decreased during the 5 years between 1991-95. They note that use of cycle helmets increased during the same period, and suggest that this was the reason. But all sorts of things about cycle use changed during that period! Sensible people might point to the provision of cycle lanes and advance stops at traffic lights for example. For my part I feel that the increasing use of tight Lycra cycling shorts may be the secret. Being highly visible these may act as a deterrent to cars coming too close. Alternatively since it is well known that cyclists bottoms are better to look at than most peoples, they may cause drivers to slow down whilst passing. Serious injuries such as head fractures and the like are thus avoided. However one does feel more macho in Lycra, so that overall injury rates remain constant. Whatever the reason, we live in an age of what Skrabanek so eloquently called Coercive Healthism (3) and all of us cyclists will be forced into helmets before we can say brake- block. Such evidence as we have proves only that making cycle helmets mandatory reduces cycle use. Indeed they would do more good on car users and pedestrians (4). Especially since, despite government hype the imposition of seat belt use made only a temporary difference to serious injuries in vehicle accidents (5). Bad injuries to cyclists are nearly always caused by vehicles. Seperating the two by the provision of cycle lanes etc is the way to reduce the problem. I love the simplicity of cycling. I do not want an expensive, ugly piece of polystyrene stopping me feeling the wind in my hair. I look good enough in my Lycra shorts! Richard Ayres 1)Rivara F,Thompson D. Bicycle helmets: it's time to use them.BMJ 2000;321:1035-6 2)Cook A, Sheike A. Trends in serious head injuries among cyclists in England: analysis of routinely collected data. BMJ 2000;321:1055 3)Skrabanek P. The Death of Humane Medicine. The Social affairs Unit 1994. 4)McCarthy M. Do cycle helmets prevent serious head injury? BMJ 1992;305:881-2 5)Richens J, Imrie J, Copas A. Condoms and seat belts: the parallels and lessons. Lancet. 355(9201):400-3,2000 Jan 29 |
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Carlton Reid
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Editor - Oh, dear. Cycle helmets. The BMJ just loves this subject. Which makes it odd that such a flawed article was allowed to pass as an "editorial." I'm no scientist but the cracks in "Bicycle helmets: it's time to use them" are so wide you have to wonder whether the authors have themselves suffered head trauma at some stage because they clearly have massive blindspots when it comes to presenting a fair and impartial case. The main point seems to be that reports of head trauma have gone down at the same time as helmet use has increased. No other explanation is even considered. No evidence, except anecdotal, is offered for the supposed increase in helmet use. Why didn't the authors consider that cycle use may be down? Or that car speeds might have been restricted in some areas leading to less injuries? There are many possible reasons for the drop in reported head injuries. Personally I wear a helmet and it's reasonably obvious "even to helmet haters" that wearing one will prevent injury should you happen to fall from your bike. But road cyclists don't often fall from their bikes (it's different for mountain bikers) and even those that do, usually report their heads remained unmolested by tarmac. Sadly, some cyclists die from head trauma and helmets could have saved them. But look at the stats, opening the mail is a risky operation too. So is walking along the street, yet do scientists clamour for pedestrians to wear helmets? And far more deaths and head injuries would be prevented if drivers wore helmets too. I'm all for more helmet sales but whether to wear bonce protection or not should be up to the individual, not safety-nannies. As has been shown in Australia, once helmet use is mandatory, cycle use drops dramatically. And as the BMA well knows, the health benefits of cycling far outweigh the risks. So, please, let there be less one-sided scare-mongering, all it does is deflate cycle use. If safety-nannies must argue that cyclists should be dressed head to foot in armour, then at least they could argue the same for all activities, because life, dear reader, is risky. Carlton Reid
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Peter Wilkinson
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EDITOR - I am not a medic but I often read my wife's BMJ and being a cyclist I read "Bicycle helmets: it's time to use them" 1 with interest. I have no argument with the authors' analysis of injuries suffered by cyclists and their conclusion that wearing helmets has reduced the number of head injuries. I do question whether wearing helmets is the best way to get the maximum health benefit from cycling, minimising injury and maximising exercise. Cycling is very popular in Holland and Denmark yet I don't remember seeing cyclists there wearing helmets. They are provided with a safer environment through widespread cycle routes which keeps them separate from motor traffic. As a result of this policy cycling is safer and a large proportion of the population of these countries take part in good quality exercise. A study of cycling injuries in Holland and Denmark, their frequency and the proportion of serious head injuries compared to those in countries, such as the UK and the USA, where separation of cyclists and motorists is not the norm could inform the wider debate about safe sustainable transport. Peter Wilkinson 1 Rivara FP, Thompson DC, Thompson RS, Bicycle helmets; it's time to use them. BMJ 2000;321:1035-6 |
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Nicholas P Mann
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Editor - We wish to strongly support the conclusions of the recent Editorial on cycle helmets by Rivara, Thompson and Thompson which strongly recommends their widespread use1. Accidents are a major cause of death and disability affecting young people. Eight out of 10 children in this country ride bicycles and it is an activity that should be encouraged with attention paid to promotion of safe cycling. Children are more likely to fall off cycles than adults - under 16 year olds account for over 60% of those attending casualty departments for bicycle related injuries2. We have shown in a recently published study the efficacy of a bicycle helmet promotion campaign on wearing rates among cyclists less than 16 years old3. This study was carried out over a 6 year period in Reading, Berkshire between 1992 and 1998. Ownership of helmets increased during the study period from 23 to 68%, and usage rates, assessed by questionnaire (always using a helmet) increased from 11 to 31%. Simultaneously during the study period hospital casualty figures from the area showed that cycle related head injuries in under 16 year olds fell from 113 to 61 per 100,000 of the under 16 year old population. The study demonstrated the efficacy of an educational campaign in achieving higher usage rates and demonstrated a concurrent reduction in head injury rates. Currently only 18% of under 16 year olds nationally wear cycle helmets. There is now overwhelming evidence showing the effectiveness of helmet wearing in reducing head and brain injuries. In our view significant quantities of NHS resources need to be directed at this health promotion programme nationally. The Bicycle Helmet Initiative Trust is a national resource centre for bicycle helmet awareness and provides education materials to achieve the aim of increased helmet usage in children. Nicholas P Mann
Rachel Takriti
Angela Lee
Competing interest: Angela Lee is Director and Nicholas Mann Vice- Chairman of Bicycle Helmet Initiative Trust. 1. Rivara FP, Thompson DC, Thompson RS. Bicycle Helmets: It's time to use them. BMJ 2000; 321:1035-6. 2. Department of Trade and Industry. Accident figures cycle related - report. DTI Foreword/Pub 2522 Foreword/5.5kForeword/1Foreword/97Foreword/np 1995 3. Lee AJ, Mann NP, Takriti R. Hospital led promotion campaign aimed to increased bicycle helmet wearing among children aged 11 - 15 living in West Berkshire 1992 - 98. Inj Prev 2000; 6 (2): 151-3 |
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P S Wootton, M.Sc. student in Exercise & Nutrition Science University College of Chester
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May I begin by congratulating you & your colleagues on your work. It was certainly an intresting read that brought up a number of asreas which will no doubt lead to more continuous debate. I wish to comment on one particular statement made by one paper you included and the ACTUAL practicality and somewhat mis-conception of helmets. In your paper, Hillman (1993)states: "Cyclists ride in a less cautious manner so there overall risk of injury is unchanged". I find this quite alarming for a number of reasons (i) how does Hillman justify this statement; (ii) what population did he use to measure accrue this data; what did Hillman do to test this data; (iv) how did he measure this; (v)what does he use to back up this statement, i.e., other research to back up his arguement or just hie own data (vi) & what does he suggest to rectify this ? My background includes being professional in Triathlon (7 years) based in Spain then France which included track and road cycling for a top amateur team, and the GBTrack Team for a number of years unitl last year to concentrate on my final year). To suggest that cyclist who wear helmets ride less cautiously is an extremely proposterous and ignorant remark, especially when one looks at the incident rate of cycle-vehicle accidents, and the attitudes of GB motorists per se. A number of factors need to be taken into accopunt of these facts: - cyclists are often treated with enourmous contempt and abuse (including "road rage" in numereous forms) by vehicle users for being on the road; - if such a driver is forced to slow down for a couple of seconds, then from the reaction of the driver, one would think that their world will end; - the fact that some drivers will NOT use their indicators to denote which way they are travelling at a junction, thus cuasing the cyclist/s to either crash or a v. near miss; - some drivers will pull out of a junction and on to a cyclist/s in the hope that they can get out before the cyclist reaches their (motorists') stationary position (at the junction); - certain drivers will not give cyclist/s adequate room when overtaking, narrowly missing the cyclist/s; - in addition to this, forgetting that their vehicle may have a drag effect (i.e., depending on the speed of the vehicle and the size - the bigger & faster the vehicle, the geater and more letal the drag). There are copious amounts of incidents that can be accounted for by cyclists as to the behaviour of drivers. In a country where cyclists are regarded as a nuisance to be sometimes tolerated when it suits, by a MAJORITY, is indicitive of the incidents that occur. The fact that they are not reported to the Police doesn't mean that they don't occur. Go along to any cycling club BCF or CTC affilitated or anyone out for a leisurely ride and they will tell the same horror stories or at least, v. similar ones. The fact is, that the attitude of GB motorists needs to be addressed. This needs to filter through to the Diriving Test with provision made for cyclists on the road and how to cater for cyclists on the road. In mainland Europe, e.g., Spain & France (both of where I lived for many years as a Semi / Professional trasithlete & cyclist), cyclists are catered for by way of the judical Law. In Spain, cyclists motorised or otherwise must travel on the equivalent of the "hard shoulder" which are aon ALL roads main or streets. In France if a motorist hits a cyclist, then they must prove their innocence, which is why a French motorist would rather hit an on-coming vehicle than a cyclist. They will think nothing of waiting for an on- coming car to pass before overtaking the cyclist/s and giving such room as to travel on the opposite side of the road, literally. In Holland, Belgium, Italy, Denamrk, Sweden to name but a few, if a motorist hits a cyclist and is at fault then they are dealt with v.stringently by the Law. If drinking or drugs are suspected and proven their is a jail sentence MINIUMUM !! This also extends to reckless driving. In this country, the judges at most will issue a fine, slap on the wrists and no more is said. It is the attitude of the GB driver that puts the GBcyclist/s in danger, and that fact is, having to slow down for a couple of seconds is fatal to the point that their whole world will cease to exist. If Hillman wishes to disprove me, then I would suggest that Hillman invest in a cycling helmet and bike and go out cycling on roads and not just quiet roads, but main roads as these are usually the only way to get out of the "hussle & bussle", for at least 1hr at a time 3 times p/wk for 3-6 months. This could be the basis of a prudent research paper. With this in mind, Hillman could see 1st hand, whether or not he rides in a less cautious manner. Then to validate his findings, to try it again only this time without a helmet and then again with a helmet. After this he could look at his original statement (1993) and see how accurate it was !! I conclude that such statements by Hillman as been expressed are not only ludicrous but also dangerous because it reflects the majority attitude - "cyclists shouldn't be on the roads & if they crash, it's their own fault for being on the road in the 1st place". I hope that this has made some sense and has remained as polite as I intended. I would like to thank you for your valuable time and patience in reading this reply to your original paper. I remain, yours sincerley . . . Phil Wootton |
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David W Evans, Retired cardiologist
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Dr.Nigel Perry is to be congratulated on drawing attention to the poor science being propagated by the advocates of compulsory helmet use when cycling. The plausible presentation and reiteration of such insecure or even irrelevant data has, in other areas of controversy, proved powerfully misleading in the past. The widespread acceptance, after official promulgation(1), that a few bedside tests had the power to determine that "all functions of the brain had permanently and irreversibly ceased" is a case in point. That unscientific notion held sway for some 16 years - to be replaced by the similarly insecure idea that they suffice for the diagnosis of irrecoverable loss of consciousness(2). Perhaps we may look forward to genuinely science-based discussion in the next Millenium. 1. Conference of Medical Royal Colleges and their Faculties in the UK,1979,BMJ;1:332. 2. The Demise of "Brain Death" in Britain,2000,in 'Beyond Brain Death',Eds. Potts,Byrne & Nilges,Kluwer Academic Publishers,Dordrecht,139-158. David W.Evans, 27 Gough Way, Cambridge, CB3 9LN |
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Malcolm Wardlaw
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Cyclists were the only group of UK road users to suffer a sharp increase in fatalities during the Nineties (1), yet cycling was in decline all through the decade(2). Cyclists were the only group to take up helmet- wearing during that period. It is interesting that Cook and Sheikh selected the period 1991 to 1995 for the basis of their study. During that period, the country was in the deepest recession since WW2; casualties and severity of injury fell for all road user groups. Cyclists did not benefit any more than either car-users or pedestrians. I ask Cook and Sheikh a question; why did they not select 1994-1998? You see, during that period the Fatality Rate of cyclists jumped by 25%, and during that period cycle helmets became much more widely popular than they had been. Is that coincidence or consequence? Could it not be that at least some helmeted cyclists, misled by the likes of Cook and Sheikh, Thompson and Rivara to believe they had protection that wasn't there, lowered their guard just a little and thus reacted fractionally less quickly come their terminal emergency? Hmmm? It seems to me fishy in the extreme that a period of rapid take-up in helmet wearing saw a sharp increase in fatalities that cannot be accounted for by any trend for other road users (pedestrian deaths continued to decline during 1994-98). For the record, Scuffham et al studied the effects of voluntary helmet wearing in New Zealand during 1989-1992, during which period helmet use rose from nil to 65%. That's a pretty sharp rise, not so? If helmets were effective, such a sharp rise would have had an effect on injury patterns - not so? Scuffham concluded no reduction in head injury admissions (3). More recently, the Scuffham team returned to the topic and examined the effect of the law of 1994, which increased wearing rates to 95%. This time they concluded a reduction of 19% in admissions for head injury (4). Their results are inconsistent - as they admit. They included superficial injuries (scalp lacerations) in their definition of head injury. They also failed to explain a disturbance in the injury trends during the years immediately prior to the law. This disturbance may explain the inconsistency in their results. The imposition of law did cause a reduction in cycling. Experience in the UK shows that if there is a decline in cycling, the level of injuries does not fall as much. Proponents of helmets never take into account that any deterrence of cycling will increase the risk of death for those who continue to cycle. Careful analysis of the Australian legislation of 1989-92 by Robinson B.(5) and Robinson D. (6) showed no prevention of head injury admissions from sharply increased helmet wearing. The reduction in cycling (-35%) was much greater than the reduction in head injury admissions (-15% to -20%), indicating an increase in risk, probably because of the reduction in cycling. Therefore, my money is on the first Scuffham study. Cyclists need to be informed of the truth. Yet today, I read in The Times newspaper placid and uncritical promotion of the Cook and Sheikh study. So much for a free press. Another question, this time for Fred Rivara and Diane Thompson. In the USA, the safety record for drivers is really shockingly bad. If the UK had the same per-capita death rate as the USA, we would see 10,000 road fatalities a year (we actually see only 3,500). Why is it you two build your positions on cycle helmets, when driving standards in the US are clearly a far more serious public health issue? Why do you discriminate against drivers in this way? A final question to leave you doctorly lot with. If I am interpreting the literature correctly, the health damage associated with NOT cycling is similar to the health damage of smoking 20 cigarettes a day. To promote cycle helmets (thereby supporting the myth that cycling is more dangerous than driving or walking) is pretty much like promoting cigarette smoking. The UK is not a fit nation. We are a nation of unfit slobs who spend too much time moulded into the driving seat of a car, clogging up neighbourhoods and imposing our pioson and danger on child cyclists (who in consequence are pressured to wear helmets). Cycling is one of the few charming, innocent, harmless pleasures left in this anaesthetic, stinking world - and it's actually good for you! So what's the deal with promoting cycle helmets? Is the professional scope of Thompson, Rivara, Cook and Sheikh really so arid that you have nothing better to do? 1. DETR. Road Accidents in Great Britain; The Casualty Report, London, DETR 1998. 2. DETR. National Travel Survey. London. DETR 1998. 3. Scuffham P, Langley JD. "Trends in cycle injury in New Zealand under voluntary helmet use." Accident Analysis and Prevention 1997;29:1 4. Scuffham P, Alsop J, Cryer C, Langley JD. "Head injuries to bicyclists and the New Zealand helmet law." Accident Analysis and Prevention 2000;32:565-573. 5. Robinson B. "Is there any reliable evidence that Australian helmet legislation works?" Paper presented at Velo Australis Conference, Perth 1996. 6. Robinson D. "Head injuries and bicycle helmet laws." Accident Analysis and Prevention 1996;28(4):463-475. |
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Philip Docking, Lecturer Nanyang Polytechnic, Singapore
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In an acticle I wrote many years ago, the need to separate motor vehicles and cyclists was stressed. Keep them apart and reduce the risk of collision significantly. However do not move them to the pavement as this causes problems for pedestrians. Then both will need helmets. |
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Peter Jacobsen, Public Health Consultant Consultant
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Cook and Sheikh [1] report a 24% reduction in serious head injuries to bicyclists in England across a four-year interval, roughly from 1991 to 1994, during which the number of injured bicyclists admitted to hospitals remained essentially constant. This reduction is noteworthy and cries out for rigorous analysis. Cook and Sheikh speculate that increased use of cycle helmets could have been a major causal agent. Unfortunately, they offer no data on this point. Insofar as the decline in cyclist head injuries was not tied to an increase in helmet usage, the suggestion in the accompanying BMJ editorial [2] that cycle helmets should be mandatory, was astonishing. What is more, the editorial overlooked compelling evidence that reforming transport policies is key to reducing casualties not only to bicyclists but to other road users as well. Whereas Cook and Sheikh used data on hospital admission, all five studies cited in the editorial used emergency room presentations, which is a lower measure of severity. The literature indicates declining benefits from helmet wearing as injury severity increases. Two reports by the authors of the editorial illustrate this limitation; from the same data set, they reported an odds ratio of 0.31 for the protective ability of helmet against head injuries presenting at emergency rooms, [3] but only 0.7 for hospital admission, and just 0.9 for severe injury. [4] Given this magnitude of risk reduction, it is unlikely that an increase in helmet use in England could explain the reduction in hospital admissions with head injuries. Moreover, that same study provides a plausible hypothesis for the 24% reduction in cyclist hospital admissions for head injuries. It explains, "[c]ollison with a motor vehicle increased the risk of severe injury more than fourfold; crashes occurring at [bicyclist] speed estimated at > 15 mph increased the risk by 20%. Helmets had no apparent effect on the risk of severe injury, probably because head injuries accounted for fewer than one in six of all injuries and the majority of head injuries were not severe.” [4] In short, limiting the capacity of motor vehicles to cause harm offer the greatest potential for reducing head (and other) injuries to bicyclists. We note further that, from January 1991, to December 1994, a period closely corresponding to that analyzed by Cook and Sheikh, pedestrian fatalities in England declined by 25%, while the number of bicyclists killed declined by 29%. [5] Since we can be sure that pedestrians were not donning protective headgear, the explanation may lie in changes in the overall road environment. And in fact, the first half of the 1990s was a time of great change in governmental policy toward transportation. As BMJ reported at the time, bicycle lanes, pedestrian priority areas, and traffic restrictions were part of the manifestos of both the Conservative and Labour parties. [6] These changes in policy have paid off in continued large reductions in the number of people killed while walking and bicycling — halving the number of non-occupants killed in a ten years — without compelling either pedestrians or cyclists to wear helmets. 1. Cook A, Sheikh A. Trends in serious head injuries among cyclists in England: analysis of routinely collected data. BMJ 2000;321:1055. 2. Rivara FP, Thompson DC, Thompson RS. Bicycle helmets: it’s time to use them. BMJ 2000;321:1035-36. 3. Thompson DC, Rivara FP, Thompson RS. Effectiveness of bicycle safety helmets in preventing head injuries. JAMA 1996; 276:1968-73. 4. Rivara FP, Thompson DC, Thompson RS. Epidemiology of bicycle injuries and risk factors for serious injury. Inj Prev 1997;3:110-114. 5. Dept. of Environment, Transport, and Roads, Transport Statistics Great Britain: 1999 Edition. 6. Godlee F. European cities move on banning cars. BMJ 1992;304:797-798. Conflicting interest: Ownership of shares in Bell Sports Corporation, manufacturers of helmets. |
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Colin Read
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Editor - Rivara et al correctly assert that the evidence that cycle helmets prevent head injury is strong.1 Accident and Emergency physicians are often frustrated at the lack of cycle helmet use, particularly in children. In Leicester almost half of people involved in cycling accidents presenting to the A&E department have some form of injury to the head or face2. We performed a prospective structured questionnaire in order to investigate the attitudes of parents to cycle helmets, and to look at the reasons children gave for not wearing helmets when cycling. Three hundred questionnaires were distributed to parents attending the A&E department with their children. There were two parts to the questionnaire, one for parents and one for the child. Children attending with injuries related to cycling were excluded. Out of 241 adults that completed the questionnaire (response rate 80%), 220 (91% of those who responded) agreed that legislation should be introduced to make it compulsory for cycle helmets to be worn. The most commonly cited reason for parents (57% of respondents) not buying a helmet for their child was that: "The child would not wear it anyway." Of the 207 children completing the questionnaire, the most common reason (in 63, 30% of respondents) given for not wearing a helmet was that it was not perceived as fashionable. Comfort and the fact that friends did not wear a helmet were other reasons cited (48, 23% for both). In analysing the group of children who thought cycle helmets were unfashionable, 24 (39%) said they would be more likely to wear the helmet if a logo of their favourite pop-star or sports team was on the helmet. Twenty-four (39%) in this group said that they would be more likely to wear a helmet if their friends did. These factors do suggest possible strategies for increasing cycle helmet use in the future. A helmet with the logo of a pop star on would be easy to produce, and one would hope that celebrities would help promote the use of cycle helmets. Cook and Sheikh stress the importance of local publicity campaigns to encourage cycle helmet use3 . We would add that measures to make helmets more appealing to children also have a role. 1. Rivara FP, Thompson DC, Thompson RS. Bicycle helmets: it's time to use them. BMJ 2000:321:1035-1036. 2. Ballham A. Absoud EM. Kotecha MB. Bodiwala GG, A study of bicycle accidents. Injury 1985:16(6): 405-8. 3. Cook A, Sheikh A, Trends in serious head injuries among cyclists in England: analysis of routinely collected data. BMJ 2000: 321:1035 Colin Read John McInerney Ravi Assomull Gautam Bodiwala Accident and Emergency Department, Leicester Royal Infirmary, Leicester LE1 5WW |
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Frederick P Rivara, Head, Division of General Pediatrics and George Adkins Professor of Pediatrics University of Washington, Seattle, WA, USA
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Our editorial on bicycle helmets and the Cook and Sheikh study has engendered a great deal of discussion in the electronic pages of the BMJ. The comments fall into a few major themes. First, factors other than increased helmet use explained the decrease in bicycle-related head injury admissions. Second, environmental measures are more important than helmets in decreasing the risk of severe injuries. Third, mandating the use of helmets can have an adverse effect by decreasing cycling as a form of exercise, and thereby increasing the risk of cardio-vascular disease. Fourth, helmets are not effective in motor vehicle-bicycle collisions, the cause of most severe and fatal injuries. Finally, the protective effects of helmets are markedly reduced by the increased risk-taking of helmeted cyclists, "risk-compensation." We agree with the comments by Nicholas Mann, PS Wootton and Colin Reed. However, the tone of the other letters is vituperative and distinctly unscientific. The letter writers counter scientific studies published in prestigious peer-reviewed publications with opinion and with unpublished studies, or with non-peer reviewed research reports. The attitude is clearly anti-evidence based medicine and public health, against the reliance on scientific literature strongly supported in the pages of the BMJ. The space limitations of the BMJ do not allow us to respond to the multiple comments at length. Two well known cycling advocates, Bill Curnow and Dorothy Robinson, have posited similar arguments to our systematic review of helmet effectiveness published in the Cochrane Library. (1) Their comments, and our responses, are fully published in that forum and will not be duplicated here. We will be answering comments from Richard Keatinge and Mayer Hillman in future issues of the Cochrane Library. Interested readers can follow the debate at the Cochrane Injuries Group website. ( www.cochrane-injuries.ich.ucl.ac.uk/HelmetComment.htm) . Few injury control professional in the world believe that helmets are the only answer for the prevention of serious disability and death to bicyclists. Other interventions, such as separation of bicyclists from traffic and bicycle rider training programs may also be important measures. However, these and other proposed interventions have not been subject to the kind of careful, rigorous research that has been done by a number of investigators examining helmet effectiveness. Such studies are welcome and clearly needed. The purpose of publishing health research, and discourse about it, is to improve the health of the public. We believe that the evidence indicates that helmets have a net positive effect on the health of the public. We look forward to the publication of future studies in the pages of the BMJ and other peer-reviewed journals examining this question. References Thompson DC, Rivara FP, Thompson RS. Helmets for preventing head and facial injuries in bicyclists (Cochrane Review) In: The Cochrane Library, Issue 4, 1999. Oxford: Update Software. Frederick P. Rivara, MD, MPH,
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Colin Guthrie, GP 1448 Dumbarton Road Glasgow G149DW
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Rivara and colleagues1 may care to reflect on the following plus two grim news stories from either side of the atlantic. 2 and 3. Our respective cultures are abnormally car-centric and heading for a society where the elderly will only be allowed to cross roads if they are wearing full fluorescent garb 2 and waving a red flag 3. Perhaps in a few years time Rivara and colleagues will be debating the finer epidemiological points of crash helmets, fluorescent garb, red flags and even curfews for pedestrians. I was at a conference run by the Glasgow Police last week looking at how they can meet the latest Government target on halving Killed and Seriously injured children in Britain by 2010 ( Labour could have done this overnight at recent Roads review by reducing urban speed limits from 30 to 20 at a cost of only 3 minutes on the average commute but the government bottled out for fear of losing the motorists' vote ) At this conference someone from Mercededs safety research talked for 20 minutes on car safety. The whole of his talk was about 'car occupant safety' and the various electronic devices that serve to cosset and protect the driver and passengers in the event of an accident ie him going too bloody fast( and therefore , of course, encourage speeding by creating an unreal awareness of speeding danger ). I asked why he had not mentioned anything on pedestrian / cyclist survival in an accident and why had the car manufacturers shelved car design research in '85 which showed that car protection in accidents for the pedestrian / cyclist existed in the form of softened bumpers and recessed engine blocks? He admitted that 'there was no demand for this in their cars ' and 'it was sad that such safety devices do not exist'. Sad? Surely a vile indictment of our car-obsessed culture?. Helmets are just an obfuscating diversion in a dead backwater of transport safety visited by epidemiologists (who mostly don't know their cogs from their bearings) for a bit of safe statistical sport and career enhancement. The clear message from several recent response sites, touching on cycle helmet usage, is that these waters are now very dangerous areas in which to venture. We cyclists are thoroughly fed up being used as epidemiological fodder in such an area of marginal risk improvement. Back off. If public health / epidemiologists really want to make a difference then do something useful and mine the far more productive areas of speed restriction, urban design, child's play restrictions and pedestrian -safe vehicle design. Or would this research be dangerous for you? Would it bring you or your unit into conflict with local / central politicians or even funding streams? Could there possibly be public health departments out there funded by car manufacturers etc ? Don't be so obsessed with YOUR evidence base. Reality is out there staring in your face. When you are being bombed you shouldn't have to hide in shelters, you should be stopping the bombing. Colin Guthrie 1 Frederick P Rivara www.bmj.com/cgi/eletters/321/7268/1035#EL17 2 Headline:
The following story is on the front page of the weekly Birmingham
MetroNews - Thursday November 30 2000 Issue 491.
She said that five of the seven road deaths in the area since June, and most of the serious injuries, had been older people. She put the problem down to elderly pedestrians crossing in the wrong place, and not being seen until it was too late. "There has recently been an increase in road traffic collisions where unfortunately elderly people have died trying to cross the road" she said. "To stop this from happening we advise the public - especially the elderly -to wear a bright item of clothing or something fluorescent." "We don't expect to see OAPs in those bright jackets that builders wear even if it's just the bands cyclists wear on their arms, it's better than nothing." Jane Eason, from the Royal Society for the Prevention of Accidents agreed. "It is always better to try and wear something bright so drivers can make you out, like a brightly coloured or white coat."And the worsening winter weather means, if pedestrians don't look out, the death toll in Brum will rise. "People should also bear in mind that the bad weather conditions will affect the visibility of both the driver and the pedestrian," said PC Evans. "The driver's ability to stop will also be drastically reduced if the road surface is wet or icy." The Editor, MetroNews, 28 Colmore Circus , Birmingham B4 6AX 3 From: Anthony Hinxman In Salt Lake City, Utah, clusters of orange flags will be placed at
the city's most dangerous crosswalks. Pedestrians can pick up a flag if
they like, wave it at oncoming traffic and then drop the flag off in a
container on the opposite side. The city has wide streets and rapid
drivers. "Salt Lake City is a place that loves its cars," says Edie
Trimmer, head of the city's transportation advisory board. "If you want to
get across, you've got
to be young and agile." |
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Aedan McGhie, Biology teacher and cyclist Glasgow
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Would Frederick P Rivara, Diane C Thompson, and Robert S Thompson be in favour of helmet wearing for pedestrians, train passengers, airplane passengers and car passengers? If yes then what have they done to promote this? If not, why not? aedan |
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Kate Carpenter, Principal Engineer Babtie Group, Bedford
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Both the article and the response to critics fail to refer to the proportion of serious and fatally injured cyclists who are subject to emergency admission. Any casualty who is certified dead at the scene or on arrival at hospital would be omitted from the figures analysed. These casualties are the most important for considering the number/severity of cyclist casualties, and the protection offered by helmets because they represent the 'worst case'. If one considers only those who survive to A&E, all subsequent analysis is of limited value. I agree with many points made about the role of the cyclist in transport (indeed, why do pedestrians not wear helmets?) but the critical point is whether the review undertaken was worthwhile. I suggest the authors obtain figures on numbers of fatally and seriously injured cyclist casualties as a whole, then review their findings. In addition, Consumers' Association tests show enormous variation in the resistance of helmets to impact, irrespective of cost. Perhaps the first step should be to ensure that accident statistics collected locally by Police forces and collated nationally by DETR include information on cycle helmet usage. Surprisingly, even seatbelt usage is not routinely recorded in accident reports now. Without meaningful information on usage rates in total, and among casualties, and the differing levels of protection against impact, there seems little value in in-depth analysis of only some of those seriously injured. As an chartered engineer (a profession still viewed by the public as oily-rag carriers and telephone fitters) I am rather frustrated to see qualified medical professionals making fundamental omissions in a field where much more research is needed. If nothing else, perhaps the debate will encourage more people to consider wearing helmets, and to reduce the number of fatal accidents I and my colleagues must investigate. |
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Dennis Crowley, Consultant Pasadena, California
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Rivara responds, explaining that they focus on helmets to protect bicyclists from injuries, with "Other interventions ... have not been subject to the kind of careful, rigorous research that has been done by a number of investigators examining helmet effectiveness." [1] That explanation reminds me of the man who lost his keys: One night a fellow was intently looking around the on the ground under a lamp post, obviously distraught. A passerby asked what was wrong and if he needed assistance. "Yes, I lost my keys." "Where?" "Over there," pointing down the street. "Well, if you lost them over there why are you looking here?" "The light's better here." 1 Frederick P Rivara www.bmj.com/cgi/eletters/321/7268/1035#EL17 |
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M Wardlaw, Business analyst
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This non-issue will destroy road cycling unless you drop it. My paper on cycling “Three lessons for a better cycling future” was published in the Christmas edition of the BMJ - and I must extend my gratitude to the Editor and Selection Board for having had the candour to publish its unauthorised views. However, you in the medical profession have largely cold-shouldered it and the media utterly ignored it. Now it can be safely forgotten. Just the other week I read a piece on cycle helmets by Tam Dalyell in New Scientist magazine, which revealed all the normal ignorance of and contempt towards cycling by the political class. To give Mr Dalyell his due, he did change his opinions after I had sent him corrective material - but he had been misinformed in the first place by precisely this editorial by Dr Rivara, promoting misleading research by Cook and Sheikh. The whole issue of risk when cycling is being left to politicians badly advised by research programmes of extremely dubious quality. There is no political protection of the cyclists’ case and there never has been. A criminal is innocent until proven guilty - that basic right has never been accorded to cycling, and efforts to place the risks of cycling in perspective are being ignored by the safety establishment - as is the uncomfortable fact that cyclist deaths increased by 25-30% after 1994 during years of continuous decline in mileage, a jump in fatalities not seen for any other user group. Cycling in this country is going to get further marginalised by bad research, political expediency and newspapers ever-eager to have a go at cycling. By the time critics like myself have inspected the research and found it wanting - even suspiciously selective - the damage is done. The BMJ accepted my Rapid Response critical of the Cook and Sheikh research (“Subsequences and consequences”) for publication in the paper journal, and I thank the editorial staff for that, but a letter published months after the event is not going to catch one shred of media attention. The truth is nowhere in sight. Suggestion, selection and misrepresentation are winning. Public health is the loser. Unless something effective is done to halt this process, the consequences for cycling over the next few years will be no different from an actual helmet law. The appeal of cycling will fade, participation will dwindle, risks will go up, public health will suffer. The National Cycling Strategy will be bleated and the targets reset as they expire. It is getting less and less bearable to walk or cycle even around the suburbs. No one cares. The absolute servility to the motor vehicle is now evidenced in children and pensioners being pressured to wear dayglo jackets when walking. It is only a matter of time before some darling of safety promotes walking helmets for schoolchildren. No one dares to question the pre-eminence enjoyed by those who drive. I drive myself, but I cannot grant that I should have such privileges over others merely because I can hurt them if they get in my way. That is barbarism, but there is no political criticism of it. As I see it, the only measure likely to alter current trends is strong editorial criticism by the medical journals - the kind of tough stuff that not even the Daily Mail can ignore - and strong criticism by GPs at the local level. The oppression of walking and cycling is harming health. The amenity of our lives is being wasted serving juggernauts and essential car use. Children have no freedom. The situation is allowed by a particularly obnoxious, unmentioned public contract: you can kill my child, but I can kill yours too. The politicians remain servile to the status quo, behind their beaming smiles. This deplorable state of affairs has to be attacked. The BMJ has carried several editorials over the last year critical of the harm to life from excessive dependence on motor transport, but the message just does not seem to be getting into the House of Commons, let alone out to the wider public. Well, I hope you doctors now understand the health consequences of silence on this issue. |
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Michael R Mott, Engineer/Scientist Boeing
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Editors: Peter Jacobsen's letter was well researched, well written, and perhaps explained the data better than TRT themselves did. A widely- respected publication such as the BMJ should not allow TRT to respond to Peter's serious arguments by calling his response "unscientific and vituperative". A serious intellectual discussion of this important public health issue demands better than this and as editors you must tell your readers that TRT failed in their obligation to seriously discuss the issues raised in Peter's letter. |
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Ken Bidgood, Consultant O&G Taunton and Somerset NHS Trust
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The use of Cycle Helmets is recomended in the editorial from Rivara et al. I use one and I think it may have saved me an occipital injury during an episode of lost concentration leading to involuntary contact with the road. However the gentleman who passes me regularly in his Porsche at high speed frightens me far more. Please could the BMJ point to the real problem - if we were to have speeds limited to perhaps 20 MPH as suggested recently in New Scientist then road injuries would be reduced and the benefits of cycling would then outway the slowness. What is more the climate might benefit. |
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daniel james keown, SHO emergency Wellington, New Zealand
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Bad science Would Thompson, Thompson, and Rivara please stop quoting the old, well performed, but essentially flawed case control studies into bike helmets please. Newer ecological studies have replaced them. The old studies have never showed that bike helmets protect against head injury, merely that people wearing bike helmets are less likely to present with a head injury. It may sound like splitting hairs but it is for exactly this reason that DBRCT were introduced. I'm afraid that they are sounding like a tired old record and a little annoying. I wonder if they are actually interested in what has happened in the REAL world since legislation or our so myopic that they have not looked past there own flawed analysis. |
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