The Thunder From (mostly) Down Under
November 16, 2013 20 Comments
I’ve been an Associate Editor for CJSM for just over six months now, and have written over 50 posts for this blog. I have never received so much traffic and commentary in this brief tenure as I have on my most recent two posts: A Discussion on Mandatory Bicycle Helmet Legislation and a poll about the same. Both relate to two very interesting pieces in the most recent, November issue of CJSM that I encourage you to read: “Bicycle Helmets: Don’t Say Something by not Saying Something” and the Canadian Academy of Sport and Exercise Medicine Position Statement on Mandatory Bicycle Helmet Legislation.
I have received an overwhelming and gratifying response to the post and the poll, most especially from Down Under: Australia and New Zealand have in place mandatory bicycle helmet legislation (MHL), and there are thunderous voices coming from there dissenting with their respective nation’s MHL. I have especially appreciated the voices that avoid references to Hitler and religious zealotry and instead share with me evidence from the medical literature on the issue. I encourage you to go the comments section on both posts to see this robust discussion. I have passed the information on to the papers’ authors as well.
If you’re reading this and you disagree with MHL initiatives, I’d ask you to take one more poll. I have been curious to understand what single issue folks find most drives their opposition to MHL. So, if you could take a moment to take the poll below I’d appreciate it. I’ll share the results from this poll and the previous one in an upcoming post.
Keep the comments coming (as they say in All I Really Need to Know I Learned in Kindergarten, Be nice and play fair! All comments are moderated). And, as ever, have a great weekend.
About sportingjim
Clinical Journal of Sport Medicine Blog 
The biggest turn-off for me was the greatly increased disregard by vehicle drivers for my safety. It happened fairly soon after I started wearing a helmet because of the law. From a safe, pleasant activity, commuting by bike became like too dangerous an activity for a normal, sane woman.
This may explain the gender imbalance of cyclists in Australia. Census data show cycling to work in Australia is still much lower than pre-law levels – http://cyclehelmets.org/1194.html
The main people you see on bikes are fit, you, sports cyclists wearing helmets and the lycra uniform. The only bikes you see in the shops have no mudguards or luggage racks, so are quite uncomfortable for commuting or shopping. People who buy them for this purpose probably give up before they get anywhere. This explains the high bike ownership, but low usage.
Because of reduced safety in numbers, exacerbated by the dramatic drop in children’s cycling, drivers have forgotten how to share the road with unprotected road users.
Helmet laws are a lose-lose-lose-lose situation, making life less convenient for cyclists, less safe because of reduced safety in numbers, less safe because of increased driver aggression, and less safe because there are few cyclists to work with local authorities on the design of improved cycling facilities. The average highway engineer’s idea of “cycling facilities” costs heaps of money but little, if anything, to make cycling more attractive or convenient! If, as your poll suggests, there was only one problem with helmet laws, it might not have been all that bad. Unfortunately, it’s *all of the above*, and much, much more.
Other countries take advantage in the renewed interest in public bike schemes and cycling for transport for health and the environment, Despite helmet laws, injury rates per kilometre cycled are much higher in Australia than countries with more cyclists, and improvements continue to be held back by a silly law that has had the opposite effect to what was intended.
Thanks for that thoughtful reply! Good to hear from the women in the crowd as well!
It seems that Commuter Cyclist may be suffering from a nocebo-like effect, possibly brought on by exposure to the misinformation at cyclehelmets.org.
Your comment that you have ‘especially appreciated the voices that avoid references to Hitler and religious zealotry and instead share with me evidence from the medical literature on the issue’ reminded me of this article http://therivardreport.com/hell-yes-and-hell-no-to-bike-helmets/. Robert Rivard describes one of the people commenting on an earlier helmet article as ‘He drifts off into unflattering comparisons of pro-helmet advocates with Nazi propagandists . . . cites the Bicycle Helmet Research Foundation and its website, cyclehelmets.org, which he calls the most comprehensive website on the subject. My reading of the site is that it would be more accurate to label it the Anti-Bicycle Helmet Research Foundation. All of its content appears to attack the helmet industry and any industry or independent researchers whose studies draw clear links to increased risk of head injuries for cyclists who don’t wear a helmet’.
Some examples of BHRF material that is, at best, ‘misleading’ (and frightening, given that people may be using the site to ‘inform’ their helmet-wearing decisions) . . .
One page on the site describes this study http://www.ncbi.nlm.nih.gov/pubmed/?term=elvik+meta+helmet as ‘Attewell et al influenced by publication and time-trend biases. When controlled for, the protective effects of helmets are smaller. Adding new studies, no overall benefit of helmets found’. In fact, the differences between Elvik’s and Attewell’s results were trivial. It is appalling that the BHRF site fails to note the BIG benefits for the most serious of (head) injuries, brain and fatal injuries. The (fixed-effects) ORs in Elvik’s paper were 0.42 (95% CI 0.34-0.53) for brain injury, and 0.23 (95% CI 0.08-0.66) for fatal injury. (As described at http://blogs.bmj.com/injury-prevention/2013/03/12/the-never-ending-bike-helmet-saga/, the random-effects results were not reproducible, 2 whole of article corrigendums have been published, but do not appear in PubMed.)
Another page on the site claims that, with respect to this study http://www.monash.edu.au/miri/research/reports/muarc076.pdf, ‘Researchers in Victoria found a similar trend, but mistakenly concluded helmets were remarkably effective. They didn’t bother to check that the same trend was evident for pedestrians, so had nothing to do with helmets!’. In fact, the authors included both cyclist non-head and pedestrian head injury hospital admissions in their models to control for the trend. The site also fails to note that
– the proportion of serious/severe (AIS3/4) cyclist head injury hospital admissions dropped by 40%
– the number of AIS3/4 cyclist head injury admissions dropped by 60%, when the number of pedestrian head and cyclist non-head admissions each dropped by 20%
Yet another page down-plays the injury reductions in this study https://www.bicyclenetwork.com.au/media/vanilla/file/SA%20Helmet%20eval%201994%20SA%20Marshall.pdf, neglecting to note that Marshall and White reported that in the 2 years after the law, compared to the 2 years before the law
– there was a 27% reduction in non-cyclist concussion admissions, and a 54% reduction in cyclist concussion admissions
– cyclist non-preventable injuries reduced by 9%, and cyclist potentially preventable injuries excluding concussion reduced by 41%
The site also fails to note that the household survey in the Marshall study (which were not subject to the vagaries of the weather) showed that 18 months after the law the level of cycling was the same as 18 months before the law (p<0.05)
The site also fails to note that with respect to the census data
– in Melbourne (our 2nd biggest capital city), there was no change in the % cycling to work in the censuses either side of the helmet law
– in Canberra, the % of people cycling to work was higher in the post-law census than the pre-law census
– other modes of travel to work decreased by at least as much as cycling
– between 1986 and 1996, cycling to work dropped by about the same amount as bus and train (and less than ferry/tram) travel to work
– at the 1991 census, jurisdictions with helmets laws comprised about 70% of the Australian population, between 1986 and 1991 cycle travel to work dropped by 7%, bus travel to work dropped by 14%.
– between 1991 and 1996, when the remaining 30% of the population was also subject to helmet laws, cycle travel to work dropped by 38%, walking to work fell by 36%.
The site contains a reference to this article ('sceptical' of helmet efficacy), which was published a few months ago, http://www.ncbi.nlm.nih.gov/pubmed/23674137 (Dennis), yet still contains references to an article (which found against helmets), despite the fact that the article was retracted almost 3 years ago: (http://www.safetylit.org/citations/index.php?fuseaction=citations.viewdetails&citationIds%5B%5D=citjournalarticle_302065_22).
The site fails to mention these studies, which were published BEFORE the Dennis study, and completely discredits Curnow’s DAI ‘theory’: http://www.ncbi.nlm.nih.gov/pubmed/23377086, http://www.ncbi.nlm.nih.gov/pubmed/23697898, http://www.ncbi.nlm.nih.gov/pubmed/23339779. (Curnow is a member of the BHRF ‘Editorial Board’ http://www.cyclehelmets.org/1121.html.)
Rivard’s comment that it wood be more accurate to label the BHRF ‘the Anti-Bicycle Helmet Research Foundation’ reminds me of the Australian Vaccination Network, which ‘claims to be a lobby and support group that promotes health choices. But the New South Wales Fair Trading Department says that is misleading because it is, in fact, an anti-vaccination group’ (http://www.abc.net.au/news/2013-06-13/anti-vaccination-campaigners-trying-to-overturn-nsw-name-change/4752844).
Like many polls the result depends on how the question is crafted. In this case of multiple choice answers, and how the answers are crafted too. Comments as follows,
1. “Focus on helmets put the onus on the wrong group: bike safety should start with safe roads and changed car driver behavior”
This is too narrow and exclusionary. Helmet promotion certainly has the effect of blaming the victim, but bike safety starts with the cyclist and skills acquisition, along with the other two mentioned – see Peter Clinch’s video.
2. “Bicycle helmets do not do what they are purported to do: they have minimal benefit in reducing head trauma”
Again narrow, since it has not been demonstrated they do no harm. Until they do, I shall apply the precautionary principle. Why not “… : they have minimal benefit and may exacerbate head trauma”?
3. “Biking is an inherently safe activity: insistence on helmet use sends the message that it is risky behavior”
Fine, although the public and many cyclists perceive it as dangerous as opposed to risky.
4. “I see MHL as an unjustified infringement on personal liberty”
Although I agree with this, I would prefer it asked if MHL is seen as placing a limit on freedom of choice. “Personal liberty” is a red flag to some as it is associated with the Civil Libertarian movement.
5. “The evidence I see demonstrates that MHL reduces rates of bicycle ridership.”
Fine.
Thanks, and yes, agreed, writing questions/taking polls is always a tricky subject, nothing perfect about it. I hope nevertheless enough people share what’s on their mind so that i/we can get a better sense of what the issues may be.
Jim,
I haven’t had a chance to read all the dissenting views from Australia in detail, but a quick scan reveals the usual highly selective set of citations used by the small but very vocal anti-helmet/anti-helmet-law lobby here in Oz.
Following are links to some additional papers on bicycle helmets and helmet laws from the last few years. These papers are primarily the work of statisticians and safety researchers at the University of NSW (full disclosure: I am a co-author on several of these papers). The anti-helmet/anti-helmet-law lobby here in Australia is well aware of these papers (or of at least all but the most recent two), but curiously rarely mention them.
http://www.sciencedirect.com/science/article/pii/S0001457511001485 (full text available at http://handle.unsw.edu.au/1959.4/50858 )
http://www.sciencedirect.com/science/article/pii/S0001457512004198 (full text available at http://handle.unsw.edu.au/1959.4/52350 )
http://www.sciencedirect.com/science/article/pii/S0001457512003107 (full text available at http://handle.unsw.edu.au/1959.4/52030 )
http://www.sciencedirect.com/science/article/pii/S0001457513000183 (full text available at http://handle.unsw.edu.au/1959.4/52348 )
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0075424
http://www.tandfonline.com/doi/abs/10.1080/15389588.2012.727217
Click to access 28_Wang_PR.pdf
Click to access 26_Olivier_PR.pdf
The antepenultimate paper in the list, for the first time ever, reports empirical tests of Curnow’s armchair theory that bicycle helmets increase angular acceleration of the head in an accident and thus increase the risk of DAI (diffuse axonal injury). Curnow’s theory is found to be incorrect.
The penultimate paper (a peer-reviewed conference paper) provides a detailed critique of the key studies of bicycle helmet/helmet law effects in New Zealand.
The last paper (also peer-reviewed) provides a comprehensive review of anti-helmet and anti-helmet law arguments, and surveys the scientific literature with respect to each of these arguments.
Regards,
Tim Churches
Sydney, Australia
Tim
thanks very much for that, really appreciate your sharing that listing of articles, haven’t had too many responses from the ‘pro-‘ crowd. I’ll be taking a look at those references, hope the folks following on the blog will as well. Cheers.
A shame Tim Churches didn’t encourage some real debate on the issue and reference the opposing papers by Chris Rissell at Sydney University. (Although Chris’s work not without error either.) (Jim, for some background information, Sydney & UNSW are historical rivals. I studied at UNSW.)
I’ve read some of UNSW reports and other people’s reviews of them. Unfortunately UNSW seems to have a very biased view of helmets. The problem with statistics is that it can be twisted to whatever viewpoint the author wants.
What’s that old saying – “Lies, damned lies & statistics.”
Thanks for writing, it’s not Tim’s responsibility to encourage some debate on this platform, it’s mine. I appreciate your input, I appreciate Tim’s, I appreciate everyone’s when the opinions have been shared in a civil manner. Tim’s citations are helpful to the overall discussion.
Are you familiar with procon.org? A USA website that looks at controversial issues (marijuana legalization, gun safety, etc.) and puts forth the evidence for and against, in other words gives a platform to both ‘sides’ I’ve contacted them as I think they would be a great potential vehicle for this controversial topic.
I think (and I say this for myself as well as anyone) we all need to acknowledge the inherent bias with which we approach a subject, all sides on any controversial subject need to do that. The wisdom of St. Paul (without religious overlays): “we now see through a glass darkly.”
Thanks for your contribution to the discussion.
I’m sorry, I didn’t mention the rejoinder by Rissel to our 2011 paper in Accident Analysis and Prevention because it had already been mentioned as reference [4] here: https://cjsmblog.com/2013/11/14/mandatory-bicycle-helmets-for-cyclists-tell-us-what-you-think/#comment-1805
In fact, our interest in a thorough and careful examination of the helmet data was sparked by a paper by Chris Rissel – see http://www.smh.com.au/nsw/authors-admit-errors-in-study-on-bike-helmets-and-head-injuries-20101229-19a9x.html – the Voukelatos and Rissel paper was subsequently formally retracted by the journal that published it.
For the sake of completeness, here are some other papers by Rissel on the helmet issue of which I am aware (and various commentaries and critiques of them):
[1] http://sydney.edu.au/medicine/public-health/prevention-research/pdf/HPJA_2011_Rissel.pdf
[2] Our critique of [1]: http://www.publish.csiro.au/?act=view_file&file_id=HE12076.pdf
[3] Rissel’s commentary on [1]: http://theconversation.com/make-helmets-optional-to-double-the-number-of-cyclists-in-australia-4578
[4] My critique of [3]: http://blogs.crikey.com.au/croakey/2011/12/19/the-cycle-helmet-debate-continues/
[5] p5 of http://www.eco-logica.co.uk/pdf/wtpp18.3.pdf
[6] Our critique of [5]: http://www.abc.net.au/environment/articles/2012/07/18/3546884.htm
That’s how scientific discourse ought to proceed. It isn’t a University of NSW versus a University of Sydney thing. In fact, one of the authors of one of the papers I mentioned earlier (Bambach et al.) is an injury researcher at the University of Sydney.
Tim C
thanks for sharing those references tim.
It is more than a little ‘ironic’ that BK Rydar criticised Tim Churches for not citing Rissel’s papers, then proceeded to accuse UNSW of being ‘very biased’ and manipulating their results, without providing any supporting evidence.
In addition to posting the evidence to this forum, BK Rydar should also post the incriminating evidence to http://injurystats.wordpress.com/ – ‘A Discussion of Statistical Issues Related to Injury Research’.
linda thank you for that link to injurystats very interesting. i have been first and foremost a physician, practicing clinical sports medicine, only recently stepped into the public health fold after earning my mph, so i’m still learning a lot about the details, methodology, etc. of epidemiology, injury prevention….i found that injurystats reference to be very informative, helpful to me in my learning curve.
it’s been very interesting for me–sitting several time zones and many degrees of longitude & latitude away from you all down in AUS–to see the passion this issue invokes. i have been an active bike commuter for over 20 years, have biked in africa and nz as well as usa, i’ve logged thousands of miles….i say this to note i have a ‘personal’ stake in this too, and my ultimate bias is not really about bicycle helmets but it is about the triple goals of 1) increasing physical activity in the entire population, but especially children; 2) making our environments more friendly and conducive to physical activity; 3) keeping folks safe, especially children, while they are physically active.
i try to put the personal aside though when thinking or writing about these issues. i have appreciated the postings in this commentary thread that have focused on a more dispassionate discussion of the evidence, both for and against helmets and/or MHL.
i am hopeful as this discussion continues, both ‘down under’ as well as in n. america (after all, the position statement that ignited this blog discussion was a Canadian one, not directly addressing AUS MHL) that it remains civil.
thanks for the various references you contributed in your comments.
PS here’s one of Chris’s paper. You can probably find more of them on CRAG or at the University of Sydney or the CRAG website others have mentioned.
Rissel C: The impact of compulsory cycle helmet legislation on cyclist head injuries in New South Wales, Australia: A rejoinder. Accident Analysis and Prevention 2012, 45.
Also try http://cyclehelmets.org/
One of the other problems not mentioned on the MHL debate is that it gives yet another excuse to the cyclist haters to whinge about “cyclists breaking road rules”. I have a medical exemption so I don’t wear a bike helmet. Last Friday on a social ride (on race bikes in lycra) I had a least 6 people (mostly car drivers & construction workers) yell out “put your helmet on”. I don’t see too many drivers yelling out for other drivers to stop speeding, stop talking on the phone or stop breaking all the other road rules that drivers break more often than bikes break road rules.
MHL also gives police an excuse to harass kids and adults. I don’t recall the paper reference but I remember reading a few years ago how American police were booking a very high percentage of African Americans and Hispanic people in poor neighbourhoods but very few whites. I doubt the helmet wearing rates between them is that dissimilar?
On the Sunshine Coast in Australia a couple of years ago there was a well publicised case in the media where a policeman let down the tyres of a teenage boy on his bike because he didn’t have a helmet. No big issue you think, police just made the boy walk 5 or so miles home. Well not quite. Look up the case of Daniel Morecombe who was raped a killed about 10 years ago now. (There’s now a foundation named after him & doing stranger danger education.) Daniel had been forcedly picked up by the murderous paedophiles on a busy road after a public bus hadn’t stopped to pick him up. The bike boy without his helmet was left stranded by police on the same section of road. At that point in time Daniel’s body & his killers hadn’t yet been found. Can you imagine what the teenager & parents would have thought about the teenager being left in the same area that another teenager had been killed in?
Do you really want to introduce another law that subjects kids to unwarranted police & driver harassment? We need better relationships between youths and police to encourage youth onto the right path. Being harassed by police for not having a helmet will only make the situation worse.
thanks for that
When I read that rejoinder in AAP, I thought ‘whoever wrote this seems to know next to nothing about stats’. The response to the rejoinder, which is not mentioned on the cyclhelmets.org page that contains a link to Rissel’s rejoinder, re-inforces that view. For example, in response to Rissel’s ‘criticism’ that the exact ‘pivot point’ is not specified, and that the time point used by Walter et al. is ‘arbitrary . . . does not accurately reflect the real-time experience of the impact of the legislation, Walter et al. point out that Rissel got it (embarrassingly) wrong: “We clarify this by reference to our original paper (p. 2066): “Eighteen months of pre- and post-law data was therefore included for both age groups resulting in a 36 month analysis period centred on the date that the legislation came into effect and taking into account the different dates for adults and children. Thus for adults the period was from July 1989 to June 1992 and for children from January 1990 to December 1992.”’
Walter et al. also pointed out that Rissel’s claim that the Elvik results showed that helmets protect ‘at best’ 15% was absolutely incorrect. In fact, Elvik’s results show that the protection offered by helmets is 63% against fatal injury, 58% against brain injury, and 50% against head injury.
The CRAG web site is as (outrageously) biased as the BHRF/cyclehelmets site, which is not suprising, given that it Curnow’s ‘baby’ (and that Curnow is also a member of the BHRF ‘Editorial Board’). This is what a Cochrane review had to say about Curnow’s ‘contribution’ to the helmet debate:
‘His commentary contains factual errors and misinterpretations of the data. In contrast to Curnow’s claims, the Thompson 1996 study found that all types of bicycle helmets (hard shell, soft shell and foam) provided substantial protection against head, brain and severe brain injuries for bicyclists involved in motor vehicle crashes and crashes due to other causes (Thompson 1996: Tables 3 and 4). In Curnow’s Table 1 (Curnow 2005) he compares brain-injured cases to head injured cases without brain injury. He interprets the 1.06 odds ratio from this exercise as showing that helmets don’t protect against brain injury. The correct interpretation is that the protective effect of helmets is similar for both head and brain injury. Cummings 2006 explains that many of Curnow’s criticisms stem from misconceptions about the studies that have been done and about case-control studies in general. . . Hagel 2006 rebuts Curnow’s arguments and points out the advantages that well conducted case-control studies have over ecologic study designs. In reply, Curnow 2006 continues the discussion and repeats arguments which have been addressed both in this review and the comments which follow at the end of the review.’
With respect to Curnow’s 2005 article, Hagel (2006) commented that “Ironically, and most damingly, Curnow’s paper would not comply with the rigorous criteria required of a Cochrane systematic review because he fails to present all relevant evidence for the effect of bike helmet use and legislation in a balanced way”.
These 3 studies, which discredit Curnow’s DAI ‘theory’ do not rate mention on either the BHRF or CRAG sites: http://www.ncbi.nlm.nih.gov/pubmed/23377086, http://www.ncbi.nlm.nih.gov/pubmed/23697898, http://www.ncbi.nlm.nih.gov/pubmed/23339779.
Jim,
We’re not the “pro-” crowd, we’re public health and safety science researchers who are attempting to carefully and critically evaluate the evidence. We don’t have any pre-determined ideological position or belief about helmets or helmet laws. However, that said, the vast majority of research to date indicates that helmets do work as intended, although they are clearly not the complete solution to the vexing problem of cyclist safety, just one part of a solution. There is no evidence that helmets actually increase the risk of brain injury, as some claim, and we have found studies which purport to show that helmets increase the risk of an accident to be flawed or unconvincing (admittedly, it is a very difficult question to study rigorously). Similarly, mandatory helmet laws in Australia and New Zealand appear to have worked, although that is also a difficult question to evaluate rigorously than helmet efficacy or effectiveness, due to the need to rely on available data from two decades ago. Whether other countries should introduce such laws is a matter for each country – as Australians, we don’t feel it is our place to comment on policy questions elsewhere. But we understand that other countries are very interested in the Antipodean experience, which is one of the reasons why this series of new studies have been undertaken, as well as the careful re-evaluation of already published data and analyses.
Tim C
Forgive me, yes, I see what you are saying. I think I have been in the mode of fielding mostly commentaries from folks who are saying ‘no’ to MHL, ‘my bad’ as they say that I reflexively am using the words ‘pro’ and ‘anti.’
Mostly just wanted to thank you for posting a dispassionate response and good survey of the existing literature. I do want to see the evidence drive this, I understand we all have biases (impossible not to as a human being), but by all means the goal of this blog and the journal itself is to present evidence, stimulate discussion, and do it dispassionately. Your comment added to that conversation. Appreciated.
My main objection to MHL isn’t on the list, although it is closely related to the “reduces rate of bicycle ridership” option.
In my opinion, MHL is incompatible with my goal for cycling advocacy – a society where 70% of people cycle as a matter of their everyday transport. Whether or not MHL depresses ridership when cycling modeshare is around 0-5% is debatable, but it’s also irrelevant. At this level the only people who cycle are enthusiasts, and their attitudes to helmet wearing are likely to be unrepresentative of the population at large.
The issue is whether MHL prevents cycling mode share ever getting to the levels of the Dutch (approaching 70%), and we have no evidence for that either way. But nobody who wants to see that level of cycling could reasonably expect it to occur while we criminalise unhelmeted cycling.
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