Are bike hel­mets re­ally a no-brainer for cy­clists?

Central Otago Mirror - - CLASSIFIEDS -

When I was a high school se­nior, I ended up in hos­pi­tal af­ter the front wheel of my bi­cy­cle fell off when I caught some air on a kerb. I was not wear­ing a hel­met. Manda­tory hel­met laws might seem like a no-brainer. Yet when the med­i­cal jour­nal BMJ polled its read­ers in 2011, 68 per cent of the re­spon­dents op­posed manda­tory hel­met laws. Pro­po­nents of hel­met laws say they re­duce in­juries. But ev­i­dence for this claim re­mains mixed. Two stud­ies pub­lished last month came to op­pos­ing con­clu­sions. The first, pub­lished in BMJ, com­pared rates of cy­clin­gre­lated head in­juries in six Cana­dian prov­inces be­fore and af­ter they passed hel­met leg­is­la­tion. Re­searchers an­a­lysed data from 1994 to 2008 and, af­ter ac­count­ing for base­line trends, con­cluded that ‘‘the over­all rates of head in­juries were not ap­pre­cia­bly al­tered by hel­met leg­is­la­tion’’. The sec­ond study, pub­lished in the Jour­nal of Pe­di­atrics, an­a­lysed statis­tics on United States bi­cy­clists who were se­verely in­jured or killed be­tween Jan­uary 1999 and De­cem­ber 2009. The au­thors com­pared the in­jury and death rates among cy­clists aged 16 and younger in states with manda­tory hel­met laws for young­sters to rates in states with­out such laws. They found in­jury rates were about 20 per cent lower in states with hel­met laws. How could the two stud­ies come to op­pos­ing con­clu­sions? Be­cause it’s in­her­ently dif­fi­cult to mea­sure whether dif­fer­ences in in­jury rates are due to hel­met leg­is­la­tion or other fac­tors, says Jessica Dennis, an epi­demi­ol­o­gist at the Univer­sity of Toronto and lead author of the BMJ study. Hel­mets don’t pre­vent the things that cause a crash, but they do of­fer a last line of de­fence when things go wrong. Even most op­po­nents of manda­tory hel­met laws ad­vo­cate hel­met use, but they say that the neg­a­tive con­se­quences of hel­met laws out­weigh the ben­e­fits. One of the first things that manda­tory hel­met laws do is de­crease rid­er­ship, says Wash­ing­ton Area Bi­cy­clist As­so­ci­a­tion board mem­ber Jim Ti­tus. Op­po­nents also worry that manda­tory hel­met laws send a false mes­sage – that cycling is an in­her­ently danger­ous ac­tiv­ity – when, in fact, it’s an ac­tiv­ity with well-known health ben­e­fits. Mean­while, it seems that bi­cy­clists wear­ing hel­mets may en­cour­age riskier driv­ing by mo­torists. Traf­fic psy­chol­o­gist Ian Walker from the Univer­sity of Bath equipped a bike with a sen­sor to record the dis­tance be­tween him and pass­ing ve­hi­cles. He took more than 2300 mea­sure­ments and found that mo­torists passed him more closely when he wore a hel­met. The abil­ity of bike hel­mets to re­duce in­jury has been over­stated, Ti­tus says. Hel­mets are some­times said to re­duce the risk of head in­jury by 85 per cent, but that statistic comes from a 1989 study that has not been repli­cated. ‘‘Stud­ies in the last 20 years have cal­cu­lated that hel­mets pre­vent 10 to 40 per­cent of head in­juries,’’ says Ti­tus. His ar­gu­ments ap­par­ently con­vinced the US Cen­ters for Dis­ease Con­trol and Preven­tion and the National High­way Traf­fic Safety Ad­min­is­tra­tion. Last month, both agen­cies re­moved the 85 per­cent claim from the in­for­ma­tion they dis­sem­i­nate to the pub­lic. ‘‘We should be talk­ing about other strate­gies to re­duce cycling in­juries’ be­yond hel­mets,’’ Dennis says. Her study did show that in­jury rates dropped af­ter hel­met laws were im­ple­mented, but the ef­fect dis­ap­peared when she took into ac­count the rate at which in­jury rates had been fall­ing be­fore the laws took ef­fect. This sug­gests that re­duc­tions were prob­a­bly due to other mea­sures, such as traf­fic calm­ing, des­ig­nated bike lanes and safety cam­paigns. Th­ese days, I al­most al­ways wear a hel­met when I ride, but I recog­nise that it’s my last line of de­fence. Not long af­ter my crash, a friend of mine ex­pe­ri­enced a nearly iden­ti­cal wreck. He was wear­ing a hel­met, yet his in­juries were sim­i­lar to mine. Our wheels flew off be­cause the quick­re­lease mech­a­nism for the front wheel had come un­done. A few years af­ter my wreck, bike man­u­fac­tur­ers be­gan em­ploy­ing a safety ap­pa­ra­tus to pre­vent this.A hel­met may have less­ened my im­pact, but to pre­vent the crash in the first place, I needed a safety strat­egy that looked be­yond the hel­met.

Bi­cy­cle main­te­nance: You’re never too young to learn how your bike works.

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