Re-analysis challenges key helmet research
A peer-reviewed paper accepted for publication in Accident Analysis & Prevention
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Thompson RS, Rivara FP & Thompson DC. Cochrane Database of Systematic Reviews, The Cochrane Library.
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This page gives information about this paper and summarises the key criticisms.
The Cochrane database has established a reputation as a key resource for medical research. This particular review, however, has attracted considerable criticism. Some of this criticism is included with the reviewers' paper on the Cochrane database and thus forms an integral part of the review. However, submissions were sometimes shortened and summarised in a way that omits key concerns. See here for the full version of one detailed critique (BHRF, 1243).
Elvik, 2011 has criticised the criteria used for the inclusion of studies in this review, noting that most of the included studies were the work of the reviewers themselves. Citing criteria estalished by Littell, Corcoran and Pillai, 2008, Elvik suggests that the authors had a conflict of interest in carrying out the review which they have not declared. In considering the assessment of quality of the same papers used by Towner et al, 2002, Elvik, 2011 finds that it is not at all clear that the omitted studies were of lower quality than the studies included. A more transparent process would have included all the papers together with the publication of quality scores and a sensitivity analysis.
As part of his re-analysis of Attewell, Glase and McFadden, 2001, Elvik, 2011 considered the same studies used in the Cochrane Review and also more recently published studies. Later studies show no net benefit from helmets with regard to injuries to the head, face and neck.
Curnow, 2005 examines the Cochrane Review in detail. He concludes that the review takes no account of scientific knowledge of the types and mechanisms of brain injury. It provides, at best, evidence that hard-shell helmets, now rarely used, protect the brain from injury consequent upon damage to the skull. The review therefore is not a reliable guide to the efficacy of helmets and to interventions concerning their use.
Injury patterns in cyclists attending an accident and emergency department: a comparison of helmet wearers and non-wearers.
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See: Brief Notes
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A case-control study on the effectiveness of bicycle safety helmets.
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Principal criticisms of the review are:
Attewell RG, Glase K, McFadden M, 2001. Bicycle helmet efficacy: a meta-analysis. Accident Analysis & Prevention 2001-05 v33 n3 p345-52.
Curnow WJ, 2005. The Cochrane Collaboration and bicycle helmets. Accident Analysis & Prevention 2005;37(3):569-573.
Elvik R, 2011. Publication bias and time-trend bias in meta-analysis of bicycle helmet efficacy: A re-analysis of Attewell, Glase and McFadden, 2001. Accident Analysis & Prevention 2011;43(3):1245-1251.
Gregory K, Inwood C, Sexton B, 2003. Cycle helmet wearing in 2002. Transport Research Laboratory Report 578.
Littell JH, Corcoran J, Pillai V, 2008. Systematic reviews and meta-analysis. Oxford University Press ISBN13: 9780195326543.
Mok D, Gore G, Hagel B, Mok E, Magdalinos H, Pless IB, 2004. Risk compensation in children's activities: A pilot study. Paediatr Child Health 2004;9(5):327-330.
Towner E, Dowswell T, Burkes M, Dickinson H, Towner J, Hayes M, 2002. Bicycle helmets - a review of their effectiveness: a critical review of the literature. Department for Transport Road Safety Research Report 30.