Cycle helmet law not properly assessed
Reading the article, The effects of provincial bicycle helmet legislation on helmet use and bicycle ridership in Canada (ref 1), it appears the conclusions reached were ill considered and unreliable for a number of reasons.
The article concludes that helmet legislation is not associated with changes in ridership. This statement is somewhat misleading. Fig 3 in the article shows trends of recreational bicycle use and the mean number of times cycled in Alberta and Prince Edward Island. Alberta youth data 2001 shows approximately 58% use bikes, 30 times a year, a combined product of 17.4 may indicate the level of cycling activity. In 2007, 58% also used bicycles but only 16 times per year, indicating a product of 9.28 and suggesting a reduced level of cycling activity by 47%. For PEI by similar calculation, in 2001, 73% x 38 = 27.7 and in 2007, 66% by 39 = 25.74, reduced cycling 8%. The articles does not provide data on the helmet wearing rates in either Alberta of PEI and therefore it lacks essential data to make reliable judgements, except possibly to say youth cycling has been discouraged. No information is provided on enforcement levels for helmet use, police data on fines for example, whereas in Victoria, Australia they issued more than 19000 fines in the first 12 months of their helmet law.
Fig 2 shows a wearing rate of 32.9% for youth in Saskatchewan and it is of interest because the head injury rate quoted by Macpherson et al 2002 (ref 2) was 9.78 for children 5-19 years in Saskatchewan, compared to an average for provinces with helmet legislation of 9.96. Ontario is similar with a low head injury rate but the wearing rate from before legislation to after was similar at about 46% (ref 3). Both results indicates helmets may have little bearing on the head injury rates and other aspects could be involved, taking more care when cycling for example.
The article mentions national response rates of 84.7%, 80.7%, and 78.9%, respectively, indicating a reduction and could this reflect people who may cycle less due to having a legal requirement not responding? People may also be less inclined to admit not wearing a helmet and thus breaking the law, so is the telephone survey process a reliable guide compared with road surveys for example.
The article contains no data on the accident rates, enforcement rates or head injury rate changes but advocates helmet legislation. It refers to a meta-analysis of five case control studies of cyclists seen in emergency departments found that helmets significantly reduced the risk of head, brain, and severe brain injuries by 63- 88% among cyclists of all ages. However, the 5 reports included in the meta -analysis were primarily comparing cyclists who had chosen to wear helmets and research suggests the accident rates and injury rates can change for various types of cyclists significantly.
The article mentions, bicycling is among the top five physical activities practiced by Canadians; however, benefits to physical health and to the environment must be considered in light of the risks of injury. Between 1994 and 2004, 44 577 hospitalisations occurred due to cycling incidents in Canada, representing 2% of all hospitalised injuries. The health benefit of cycling are not discussed in detail that would have helped to promote a balanced view, e.g. In 2001, deaths in Canada (ref 4) due to all circulatory disease were approximately 60,000 compared to 63 from cycling. Type 2 diabetes is one of the fastest growing diseases in Canada with more than 60,000 new cases yearly (ref 5). Per million population, approximately two cyclist deaths occur annually compared with 2000 from circulatory diseases. Exercise helps to avoid depression and annually about 3665 individuals commit suicide, including a youth category of approximately 500 (ref 6). Exercise also helps to avoid stroke leading to brain damage. During 2003/04, 26,676 patients were admitted for ischaemic stroke (ref 7). Physical inactivity, high blood pressure, obesity and diabetes continue to contribute to heart disease and stroke in Canada and cycling helps to avoid all these problems. Dr Hillman from the UK's Policy Studies Institute calculated the life years gained by cycling outweigh life years lost in accidents by a factor of 20 to 1(ref 8).
The UK's National Children's Bureau (NCB) provided a detailed review (ref 9) of cycling and helmets in 2005 stating the case for helmets is far from sound, the benefits of helmets need further investigation before even a policy supporting promotion can be unequivocally supported,. the strong claims of injury reduction made by helmet proponents have not been borne out for fatalities (which this paper argues is the most methodologically sound test of effectiveness) in real-life settings with large populations. (page 46).
The case for helmets is not conclusive because several reports contain details which raise serious doubts whether helmet wearing improves safety overall. Data from Canada also indicates that the accident rate can increase by wearing a helmet. My report, Evaluating bicycle helmet use and legislation in Canada (ref 3) shows why helmet legislation and helmet promotion is not justified and it is important to fully consider all of the evidence. Additional information is provided in an assessment of the USA and their state bicycle helmet laws (ref 10).
Jessica Dennis, Beth Potter, Tim Ramsay, Ryan Zarychanski. The effects of provincial bicycle helmet legislation on helmet use and bicycle ridership in Canada. Inj Prev 2010 16: 219-224 originally published online June 29, 2010
2 Macpherson AK, To TM, Macarthur C, et al. Impact of mandatory helmet legislation on bicycle-related head injuries in children: a population-based study. Pediatrics 2000;110:e60.
3 Clarke CF, Evaluating bicycle helmet use and legislation in Canada http://www.cycle-helmets.com/canada-helmet-assessment.doc
4 Health indicators, January 2005, Statistics Canada , Catalogue no. 82-221, Vol 2005 No1.
5 Health Canada, It's Your Health, Type 2 Diabetes http://www.hc- sc.gc.ca/iyh-vsv/diseases-maladies/diabete_e.html accessed 17.02.2008
6 Kutcher SP, Szumilas M, Youth suicide prevention, CanMedAssocJ, 29 Jan ,178,(3) 2008
7 Medical News Today, Weekend Hospital Admission Increases Fatality Risk Of Stroke, http://www.medicalnewstoday.com/articles/64884.php , accessed 18.02.2008
8 Hillman M, CYCLE HELMETS the case for and against Policy studies Institute, London 1993
9 Gill T, Cycling and Children and Young People, A review, National Children's Bureau, 2005. http://www.cycle- helmets.com/cyclingreport_timgill.pdf
10 Health and safety assessment of state bicycle helmets laws in the USA http://www.ctcyorkshirehumber.org.uk/USA_helmet_laws.pdf
Conflict of Interest:
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