The bike helmet lobby and scientific integrity

September 3, 2014

The strong bike helmet lobbying push seems to have started with a widely quoted 1989 paper from Thomson & Rivara, [1] that makes the bold claim that:

“we found that riders with helmets had an 85 percent reduction in their risk of head injury … and an 88 percent reduction in their risk of brain injury”

That finding has been a foundation for helmet legislation calls. Alas, after legislations were passed, be in Australia or in BC, leading to a significant increase in helmet wearing [6][17], numbers suggested by [1] never materialized [6][7][8]. Worse, the bike helmet legislation seems to have no impact on bicycling safety [7][8], the later study justifying a British Medical Journal editorial advising against helmet legislation [9].

It quickly appeared that [1] had many flaws as debunked in [10][11], and effectively recognized in a BMJ editorial [9] …That has not prevented an author of [1], Rivara, to publish many more papers always claiming impressive efficiency for bike helmet, but always presenting similar flaws as identified in [1] (confounding factors) [11]. A meta study published in 2001, [4], was also associating bike helmet with an impressive 64% reduction of risk of head injury and [3] confirmed those results and reported even more impressive reductions in the risk of head injury. Alas the studies included in both [3] and [4] have been demonstrated to be the result of a severe selection bias. After correction of this selection bias, [5] found that a bike helmet was reducing the risk of head injury by ~15%. The US National Highway Traffic Safety Administration (NHTSA)  dropped claim that bike helmets reduce head injury by 85% as this number has no credible basis.

While initial claims on the head injury risk reduction offered by bike helmet has been proven unfounded, and bike helmet legislation shown ineffective at increasing bike safety, it appears that such legislation could discourage cycling [18], what is eventually conductive to lower bike safety and less physical active population with detrimental effect on the population health [23]. Overall, a bike helmet legislation can quickly be considered as having a negative impact on public health [12]. Wherever more general economic impact is considered, the picture can become even bleaker [16].

In despite of the above, the bike helmet controversy has side tracked the research community…which focuses more on the way to mitigate the consequence of bike accidents rather than addressing their causes. As an example, several studies have reported an alarming rate of alcohol intoxication among injured and deceased cyclists, but the helmet lobby has totally seized the debate to a ridiculous point: [15] observing that half of the cyclists who died in Oregon, were alcohol intoxicated, has -in fine- no better recommendation than promoting bike helmet…among drunk cyclists!

It also take considerable energy by cycling promoters to counter misleading claims advanced regularly by the bike helmet lobby. A recent example below:

Following the publication of [19], The University of Washington and Washington State University, issued a press release titled “Study correlates presence of bike-share programs with more head injuries” stating [20]:

“Risk of head injury among cyclists increased 14 percent after implementation of bike-share programs in several major cities ”.

That has quickly being debunked as a flat lie [21], but that has made alarming headline in some media outlet (Washington Post, NPR,..).

The journalists, who are not epidemiologists can’t be reasonably blamed to reporting what is told to them by some unscrupulous researchers, considering that the study has been published, after a peer review (How to argue against that?). However in despite of evidence of misrepresentation of facts reported in various social media, they didn’t issued appropriate correction to their original story (and have preferred to close the comment section) and that is a fault.

The unscrupulous researchers can certainly be blamed for their absence of ethic:
We will pass on the unprofessional self promotion of the previous authors’ publications, such as the now well discredited [1], this, in no uncertain term:

“Solid data from well-designed studies support the effectiveness of bicycle helmets and legislation mandating their use”

As we have seen, that can’t be farther from the true, but the real problem is the thrust of the article and a misplaced conclusion, as well exposed by [22]

However, the bulk of the blame should go to the American Journal of Public Health editor; Dr. Mary Northridge; to have accepted to publish what appears to be a scientific fraud. Such an article should have never been accepted under such a form and it has clearly not been properly peer reviewed:

    Peer reviewing to work, suppose trust in the ethic of the authors (no intention to deceipt…), however, just the name of the authors should have already been sufficient to raise an eyebrow: Frederick P. Rivara, not stranger to deeply flawed studies and scientific controversy, is considered by many as nothing more than a charlatan; noticeably for reason exposed above; and considering this infamous record, the minimum of precaution could have been to choose at least some reviewers showing more scrutinity ability than complacency.


The minimum the American Journal of Public Health can do is to issue a correction, clearly stating the observed reduction in head injury in cities having a public bike share program as pointed by K. Teschke [24], this in a proeminent place and endorsed by its editorial board

In the meantimes, this episode will have helped to make clear how deep is the lack of ethic among the bike helmet supporters, to the point to even embarrasse some of them [25]. It will help to convince more people to be not only very critical of the bike helmet lobby claims, but also aware that a peer review process is unfortunatly not synonym of quality.

[1] “A case control study of the effectiveness of bicycle safety helmets “, Thompson RS, Rivara FP, Thompson DC , New England Journal of Medicine v320 n21 p1361-7; 1989

[2] “Effectiveness of bicycle safety helmets in preventing head injuries: a case-control study “ . Thompson DC, Rivara FP, Thompson RS., JAMA 1996 Dec 25;276(24)

[3] Helmets for preventing head and facial injuries in bicyclists. Cochrane Review. Thompson, D.C., Rivara, F., Thompson, R., 2009. The Cochrane Library (1), 2009

[4] Bicycle helmet efficacy: a metaanalysis. Attewell, R.G., Glase, K., McFadden, M., Accident Analysis and Prevention 33, 345–352, 2001.

[5] Publication bias and time-trend bias in meta-analysis of bicycle helmet efficacy: A re-analysis of Attewell, Glase and McFadden, 2001. Accident Analysis and Prevention 43 1245–1251, 2011

[6] Head injuries and bicycle helmet laws, Robinson DL, Accid Anal Prev. 1996 Jul;28(4):463-75.

[7] “Bicycle-related head injury rate in Canada over the past 10 years” ,Middaugh-Bonney, T.; Pike, I.; Brussoni, M.; Piedt, S.; MacPherson, A. ; Injury Prevention 16: A228 2010

[8] Helmet legislation and admissions to hospital for cycling related head injuries in Canadian provinces and territories: interrupted time series analysis.Dennis J, Ramsay T, Turgeon AF, Zarychanski R. BMJ 2013

[9] Bicycle helmets and the law, Wellcome G. And Spiegelhalter Winton D., BMJ 2013

[10] misguided doctors or marketing agents? June 11th, 2012, Cyclists Rights Action Group

[11] Misleading claims, Bicycle Helmet Research Foundation

[12] The Health Impact of Mandatory Bicycle Helmet Laws, de Jong P. ,Risk Analysis, Vol. 32, No. 5, 2012

[13] New Zealand bicycle helmet law—do the costs outweigh

the benefits? Taylor M. And Scuffham P. Injury Prevention 2002;8:317–320

[14] Bikes, Helmets, and Public Health: Decision-Making When Goods Collide. Bateman-House A. ; American Journal of Public Health ; Vol 104, No. 6, June 2014

[15] Injuries Resulting from Bicycle Collisions Frank E, Frankel P, Mullins RJ, Taylor N. Academic Emergency Medicine, Volume 2, Issue 3, pages 200–203, March 1995

[16] Few study exist – except maybe [13] suggesting that the social cost of outfitting every cyclist with an helmet was not economically justified – But as far as we know, there is no comprehensive study examining the implication of transportation mode substitution, under a transportation economic perspective (time saved or not, infrastructure cost…)

[17] Bicycle helmet use in British Columbia, Foss RD, Beirness DJ, UNC Highway Safety Research Center; Traffic Injury Research Foundation, as cited by

[18] Bicycle helmet legislation: Can we reach a consensus?, Robinson DL, Accid Anal Prev. 2Volume 39, Issue 1, January 2007, Pages 86–93.

[19] Public Bicycle Share Programs and Head Injuries; Janessa M. Graves, Barry Pless, Lynne Moore, Avery B. Nathens, Garth Hunte, and Frederick P. Rivara.; American Journal of Public Health: August 2014, Vol. 104, No. 8, pp. e106-e111

[20] “Study correlates presence of bike-share programs with more head injuries” College of Nursing; Washington State University, June 9, 2014

[21] “As if we needed another example of lying with statistics and not issuing a correction: bike-share injuries”, Phil Price,, June 17, 2014.

[22] “Hard Evidence: do bikeshare schemes lead to more head injuries among cyclists?”, Woodcock J. and Goodman A.; ; August 28, 2014

[23] Health effects of the London bicycle sharing system: health impact modelling study, James Woodcock, Marko Tainio, James Cheshire, Oliver O’Brien and Anna Goodman. BMJ 2014;348:g425

[24] letter to American Journal of Public Health Editor, Dr. Mary Northridge, by K. Teschke and M. Winters, June 24, 2014

[25] Shared Bicycle Rental Systems and Helmets, Bicycle Helmet Safety Institute June 17, 2014.


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