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Electronic letters published:
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Helmet legislation is dangerous for cyclists
Re: Better peer review is needed
Better peer review is needed
CMA irresponsible with bicycle helmets
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tOM A Trottier none
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tom{at}abacurial.com tOM A Trottier
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In the paper, they claim that the legislation increases the proportion of helmet wearing. They are correct, but looking at the larger picture, the helmet legislation is a disaster. Cyclists are more at risk after the legislation than before, ex-cyclists don't get the exercise, and all Haligonians suffer more air pollution from those cyclists who switched to cars. Using the numbers they reported, I made this analysis:
So the number of cyclists were drastically decreased (61.9%) in the first year, continuing to the second and third years (41.2%) The number of helmets counted actually dropped in the first year by 11.6%, but increased marginally (4.6%) the second and third years. Bike head injuries per cyclist-day actually INCREASED the first year.The second and third years showed a small decrease per cyclist-day. All bike injuries per cyclist-day go UP 180% in 1997 and are at an 81% increased level in 98/99 over 95/96 So helmet legislation at best reduces head injuries by reducing the number of cyclists, and helmet legislation (or fewer bicyclists) increases the likelihood of a cyclist incurring other injuries. The paper does not measure the effect on the atmosphere or on health of the reduction of cycling trips. Did heart attacks go up? Did smog and respiratory ailments increase as cyclists switched to cars? How many of the thousands of ex-cyclists and other inhabitants in Halifax sustained those "injuries"? In summary, the helmet legislation is a disaster for cyclists. tOM Trottier Conflict of Interest:None declared |
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Avery Burdett, Traffic Accident Researcher Ontario Coalition for Better Cycling
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avery{at}magma.ca Avery Burdett
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It is quite astonishing that LeBlanc et al, and Chipman, and correspondent, Wardlaw, examining the same set of data can come to diametrically opposed conclusions. Malcolm Wardlaw (echoing similar comments made by correspondent Chis Gillham) justifiably criticizes the peer review of, and the findings in, work by Leblanc et al by using the underlying data to demonstrate that the Nova Scotia bicycle helmet law has only succeeded in reducing head injuries by reducing cycling. Given the recognized health benefits of exercise, that is a disaster by any measure. Although similar problems in the Leblanc work were identified in the commentary by Chipman, she then turns around and makes the astonishing claim that Nova Scotia's law is working. That the province's expectations should be so low! It should be said there were other criticisms that have not been mentioned, for example, the unsubstantiated claim that deaths due to head injuries are preventable when helmets are worn. No credible evidence to this effect has ever been produced. Transport Canada fatality data over a twenty five period shows cyclists following an almost identical trend to pedestrians despite significant increases in helmet use among cyclists(1). Similar trends can be derived from US Department of Transport data (2). In looking at all of the criticisms, one wonders about the purpose of CMAJ's peer review. When commodities such as helmets are commonly described as "safety equipment" inevitably an end purpose for them is conveyed. It would appear CMA researchers and its peer reviewers are tainted by the same predilections that the rest of the population has on this matter. It looks like a case of "why let facts stand in the way of good intentions?" (1) Ontario Coalition for Better Cycling, http://www.magma.ca/~ocbc/fatals.html (2) Kunich, Thomas, http://www.magma.ca/~ocbc/kunich.html |
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Malcolm Wardlaw, Transport Analyst, Great Britain
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mj_wardlaw{at}hotmail.com Malcolm Wardlaw
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I have an interest in the topic of cycling, both as a cyclist and as a transport analyst working to raise levels of cycle use in Britain. I had a paper on cycling published in the British Medical Journal in December 2000 (Wardlaw, 2000). Policy and legislation in one country are likely to influence developments elsewhere. Therefore, I hope I may be able to make some outsider’s comments on the study by LeBlanc, Beattie and Culligan.
The definition of head injury used in this study is a wide one, including scalp lacerations and dental injuries. The main concern in cycle safety is to reduce the risk of genuinely serious head injuries, that is, injuries requiring admission. Evidently the wide definition adopted by the authors in this case has contributed to the positive effect reported, of a halving in the percentage of head injuries amongst all injuries to cyclists as the helmet law came into effect. A more valuable result would have followed the adoption of a tighter head injury definition, focusing on skull fractures and intracranial injuries. The data presented by LeBlanc, Beattie and Culligan show that the risk of head injury per cyclist did not change as a result of the law, but rather, the risk of non-head injury approximately doubled. This may be inferred as follows. Their bicycle count data show a 40-60% fall in the number of cyclists after the law, from 88 per day down to 33 or 52 per day. Their injury data shows a sharp fall in total injuries in 1997, but for 1998/99 the number of injuries was higher than before the law (443 versus 416). The absolute number of head injuries has fallen by half, but so has the number of cyclists, while the total number of injuries has increased. Likewise, the claim of a doubling in the rate of helmet use omits the more telling point that the absolute number of cyclists using helmets did not materially change. The Nova Scotia helmet law experience strengthens the arguments against helmet laws. There has been no reduction in the risk of head injury per cyclist – despite the loose definition of head injury used in this study. There has been a big increase in the risk of non-head injury per cyclist. There has been no material increase in the number of helmeted cyclists. There has been deterrence of cycling on a substantial scale. The deterrence of the safest mode of urban transport will not have contributed to road safety overall, nor will public health benefit overall. Utility cycling is a low-risk activity. Although cyclists in Britain do not have a notably good safety record, the expectation of a fatal crash for the average cyclist is only once in 18,000 years (3 million regular cyclists, 165 deaths per year). Experience shows that strong helmet promotion or laws bring about a low-utility, high-injury cycling culture. In countries like France, the Netherlands and Denmark, with high levels of utility cycling and much the best safety records, there is little interest in helmets. Cycling is very safe where it is popular. In France and Denmark, an hour of cycling is much safer than an hour of driving. In all countries for which I have seen data, pedestrians are more at risk than cyclists (for instance, Ramet, 1987, Robinson, 1996). This is certainly not the message delivered to the public by the current CMA policies on cycle helmets. Research here in Britain by the Transport Research Laboratory shows that the public do relate helmets and their promotion to danger, and this does deter cycling (TRL, 1998). As the relevant report comments: “Fear of traffic peril is a huge deterrent, though fear usually exceeds true danger. Discussion of safety frequently sharpens fear and so deters cycling”. The report observes that local authorities which ran prominent helmet campaigns saw a sharp drop in cycling activity. The British Medical Association reviewed the question of a national helmet law in 1999 and concluded that helmets should not be made compulsory anywhere in Great Britain. This decision was backed up by the Royal College of General Practitioners. Interested parties are advised to read the report issued by the BMA (BMA, 1999), paying particular attention to the chapter devoted to the effectiveness of bicycle helmets. It is made clear that a helmet will not prevent death in a serious crash with a motor vehicle (in as much as one can be sure of a negative). No positive estimate at all is proposed as to the likely protection from serious injury through wearing a helmet. This caution recognises real world experience in countries where helmets have come into general use, but little, if any, benefit has been observed in time trends of serious injuries (for instance, Hendrie et al, 1999). In discussing effectiveness, the BMA do not cite any research based on case-control studies. While the BMA is too polite to say so, this is tacit admission that case-control studies are not scientifically valid. Wise researchers are advised not to be too impressed by the contents of the Cochrane Library in this regard. Experience also shows that big increases in cycling do not lead to big increases in deaths and serious injuries. For instance, in Britain between 1973 and 1982, an increase in cycling of 70% was detected by the traffic census of the Department of Transport (see Road accidents in Great Britain; the casualty report, various years, issued by the Department of Transport, London). Yet during these years, the number of annual cyclist deaths actually fell by 10%. It has also been noted that in Oxfordshire, where the amount of cycling per capita is five times the national average, the number of cyclist deaths is less than half what one would expect (Rutter, 2000). The relationship between the amount of cycling and the risk of cycling has been neatly described in a recent letter to Injury Prevention (Komanoff, 2001). He warns that measures, such as helmet laws, that deter cycling will increase the risk of serious injury and death by reducing the presence of cyclists on the roads. Public policy intended to improve safety - and public health – must focus on more cycling, not more helmets. This observer must conclude that the Canadian medical profession has yet to register vital lessons in its quest to improve conditions for cyclists. Better peer review of research would be a useful first step in this process. References British Medical Association. Bicycle Helmets. BMA, The Chameleon Press, London, 1999. Department of Transport. Road accidents in Great Britain; the casualty report. HM Stationery Office, London, editions 1973-84. Hendrie D et al. An economic evaluation of the mandatory helmet legislation. University of Western Australia Public Health Dept. 1999. www.transport.wa.gov.au/roadsafety/papers/bicycle_helmet_legislation.html. Komanoff C. Safety in numbers? A new dimension to the bicycle helmet debate. Injury Prevention 2001;7:343-4. Ramet M, Vallet G. Typologies des accidentes du trafic routier a partir de 5459 dossiers. Rapports INRETS-LCB, Aug 1987 p106. Robinson D. Head injuries and bicycle helmet laws. Accident Analysis & Prevention 1996;28:463-75. Rutter H. Transport and Health. Policy report for Oxfordshire Health Authority. www.modalshift.org/reports/tandh/print_version.htm. Transport Research Laboratory. Achieving the aims of the National Cycling Strategy. TRL report 365. TRL, Crowthorne, England, 1998. Wardlaw M. Three lessons for a better cycling future. BMJ 2000;321:1582-5. |
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Chris Gillham, Freelance journalist and researcher
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journo{at}bigpond.net.au Chris Gillham
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I have just viewed the two Canadian Medical Association Journal articles, Hats off (or not?) to helmet legislation and Effect of legislation on the use of bicycle helmets, and I am dumbfounded by the CMAs irresponsible recommendation that the medical profession lobby for similar laws in other Canadian provinces. These articles come to the seemingly obvious conclusion that punishing people through legislation will cause a greater number to wear a bicycle helmet. The articles correctly note the huge reduction in Halifax cyclist numbers following legislative enforcement with consequent risks to obesity and ill health. The articles point to this reduction among both child and all-age cycling numbers, but seem oblivious to the fact that there are nevertheless more cyclists being injured. I may be wrong, but my viewing of the data indicates total injury numbers increased from 416 in 1995/96 to 433 in 1998/99). How can the CMA be satisfied with a law that reduces the number of people exercising by approximately 50%, yet puts more people in hospital than before? The proportion of head injuries between 95/96 and 98/99 fell from 3.6% to 1.6%, but in reality there were just eight less head injuries, most likely requiring a couple of days hospital admission. The Nova Scotia data confirms the disastrous consequences for public health experienced as a result of the Australian and New Zealand bicycle helmet legislation, and it is irresponsible in the extreme for the CMA to be recommending other Canadian legislatures adopt this law. The Nova Scotia data strongly suggests that the association is recommending a huge reduction in public recreational exercise, an increase in the number of people hospitalised per active cyclist, and a nominal reduction in head injuries despite about 80% of cyclists being forced to wear supposedly protective helmets. The Nova Scotia data also mirrors the legislative failures in Australia and New Zealand, where cycling popularity collapsed and record numbers of cyclists were nevertheless hospitalised. If its of any comfort to doctors concerned about the discouragement of cycling exercise (and alternative increased use of motor vehicles) the data at http://www.cycle-helmets.com re the all-age helmet law in Western Australia indicates that Nova Scotia cyclist numbers should have recovered by about 2007. In light of the legislative results from Australia, New Zealand and Nova Scotia, it is grossly irresponsible for the CMA to be recommending that the liberty and health of people in other jurisdictions also be damaged. |
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