Cochrane review of bicycle helmets: an unsound guide
The authors note that helmets are not yet widely recommended for
skiers and snowboarders because of paucity of information on their
effectiveness. Then, citing the Cochrane systematic review "Helmets for
and facial injuries in bicyclists" (Thompson et al., 2000) for guidance,
they conclude that helmet use would seem to be reasonable due to
compelling evidence that helmets are effective in preventing head, brain
and facial injuries in bicyclists.
The review by Thompson et al. is not a reliable guide to the efficacy
of bicycle helmets because Cochrane procedures did not require it to be
subject to peer review in the same way as articles published in refereed
journals. Similarly, the several comments critical of the conclusions of
Thompson et al. that have been submitted to the Cochrane library have been
referred only to the authors, who rebutted all criticisms and refused to
modify the review. In my view, they did not refute the criticisms, in
particular my own which concludes that the review provides no evidence
that the soft helmets predominant since it was published protect the brain
at all. Its claim to establish scientific evidence that all standard types
of bicycle helmet protect against brain injury is therefore not supported.
In an attempt to ensure that my criticisms of the Cochrane review of
bicycle helmets get due consideration, I submitted to the journal Accident
Analysis & Prevention an article entitled "The Cochrane Collaboration
bicycle helmets". Recently it was accepted for publication. It concludes
(a) The critical efficacy of helmets is against fatal and disabling
injury to the brain.
(b) The review's conclusion that its five included studies establish
scientific evidence that standard bicycle helmets of all types protect
against injury to the brain is not supportable because none of the studies
possesses the requisite scientific rigour.
(c) Due to the decline in use of hard-shell helmets, past findings
of their efficacy are not applicable to most helmets now used.
(d) The review is not a reliable guide to interventions and is not
suitable for the Cochrane library.
Contrary to Hagel et al. there is no compelling evidence that bicycle
helmets of current design prevent brain injuries.
Competing interests: No competing interests