09/12/2008

De negative konsekvenser af promovering af cykelhjelme

En artikel om hvorfor promovering af cykelhjelme er til ingen verdens nytte. Af en engelsk trafikplanlægger, Richard Burton in TransportXtra.

Ingen steder i verden har cykelhjelm reducereret antallet af hovedskader. Ingen steder. Hvorfor promovere de dem så?

Cycle helmets have no measurable benefits and many disbenefits, so why are they advocated?

By Richard Burton - Transport Planner - Bristol, UK

Many people will tell you that a cycle helmet is an essential piece of safety equipment and almost as many will tell you that a helmet saved their life. They are mistaken. Nowhere with a helmet law has shown any reduction in risk to cyclists, only a reduction in cyclists. The research that shows massive benefits from helmets is not reliable and is no basis for deciding policy. The evidence showing no benefit is much more reliable but is ignored by the extremely vociferous and blinkered helmet proponents.

Just over a year ago I started work on an MSc dissertation about cyclists’ views of cycle helmets and the risks of cycling and, as part of that, I undertook a wide literature review. Although aware of the controversy about helmets, and sceptical of the claims made for them, I was unprepared for the overt bias in much research, with some researchers apparently reaching conclusions before starting work – policy-based evidence making, as one observer commented.

My research investigated the risk compensation theory, where people given extra protection take more risks, thus reducing any benefit from the protection, one of the explanations put forward for helmets failing to reduce risk at a population level. This effect has been clearly demonstrated a number of times, car safety measures being the most commonly observed. I surveyed over 300 cyclists, and interviewed ten, and concluded that most cyclists have an exaggerated view of the protective effect of helmets, which was likely to lead to risk compensatory behaviour. Most cyclists also had an exaggerated view of the risks of cycling, which appeared to be associated with the exaggerated view of helmets.

Why should this matter? Cycling may not be a panacea for the ills of modern society but it addresses a huge number of them; health, obesity, pollution, congestion, global warming, noise, danger and social exclusion to name only the most obvious, and many of these are the subject of Government policy. Cycling is also extremely cheap to provide for, both personally and communally. Anyone who has visited countries that have effective pro-cycling policies will testify to the startlingly better quality of life in places that are not totally dominated by the motor vehicle.

In health terms, one researcher has said that, if the benefits of cycling could be bottled, it would be the most popular drug in the world. The promotion of cycle helmets has one single effect: a reduction in the numbers of cyclists. Given cycling’s clear and massive benefits, anything that might depress levels of cycling would have to demonstrate benefits of an even greater scale before it was even tolerated. The proponents of cycle helmets cannot demonstrate any such benefit, except with fatally flawed evidence, but many of them call for a law to force the wearing of them.

If that wasn’t absurd enough, many of the people demanding a law are health professionals, e.g. the British Medical Association. Health professionals calling for a law that will inevitably result in reduced public health! Many thousands of people in this country die early because they fail to exercise but there is no reliable evidence that cycle helmets would save even a single life, so why do health professionals want to bring in a law that would prevent many people doing something that protects them against all forms of morbidity, to quote the BMA’s own research? Similarly, the British Heart Foundation promotes cycle helmets, apparently unaware that they are increasing heart disease by discouraging cycling.

Anyone with a passing interest in helmets will have noticed two things: helmet manufacturers make very few claims for the effectiveness of their products and helmet proponents make huge claims. Manufacturers cannot make inflated claims because their advertisements have to be truthful but the helmet proponents are under no such stricture and blithely repeat claims that they know to be false, such as the Bicycle Helmet Initiative Trust’s claim on its website that helmets prevent 85% of head injuries. BHIT is a publicly-funded organisation that attempts to change the law, which is highly questionable on moral grounds, if not actually illegal.

Helmet proponents also exaggerate the risks of cycling, thus deterring many people who then see cycling as highly dangerous, but only by exaggerating the risk can helmet promotion be justified. The only thing that has been shown to improve the safety of cyclists is having more cyclists and, by deterring many, helmet promotion increases the risk for those who are left.

Cycle helmet promotion is a massive and increasingly serious own goal for many of the policy aims of any civilised society, in economic, health and other areas. Just because helmets are promoted by health professionals and politicians does not mean that they are effective, only that those people consider them so to be, without having had to go to the bother of examining the evidence.

It is time for action by our politicians to cease public funding for helmet promotion. Likewise, the health promotion bodies that currently promote helmets should cease to do so, unless their aims are other than an improvement in the public health.

But, above all, transport professionals should promote cycling as healthy, quick and non-polluting, ignoring helmets as an annoying distraction caused by a few well-meaning, misguided, do-gooders.

You can promote cycling, or you can promote helmets, but you can’t do both.

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