horizon wrote:I was hoping for some investigative evidence relating to a helmet actually used in an accident and/or conversely an accident not involving a helmet. My presumption is that minor accidents don't get investigated at all but I'm wonderting if it is these accidents where the best evidence might lie: yes, you had a fall, no you weren't injured: but why not?
Even if it is purported to be shown in some other way that helmets prevent minor injury but especially if no such evidence is currently available for serious injury, I personally would conclude that helmets are effectively useless.
The issue not that there isn't any evidence or investigation, but that the evidence and investigation doesn't produce clear, consistent and reproducible results. So what Ben Goldacre describes as "the complex contradictory mess of evidence on the impact of bicycle helmets
" gives us this kind of issue:
This finding of “no benefit” is superficially hard to reconcile with case-control studies, many of which have shown that people wearing helmets are less likely to have a head injury. Such findings suggest that, for individuals, helmets confer a benefit. These studies, however, are vulnerable to many methodological shortcomings. If the controls are cyclists presenting with other injuries in the emergency department, then analyses are conditional on having an accident and therefore assume that wearing a helmet does not change the overall accident risk. There are also confounding variables that are generally unmeasured and perhaps even unmeasurable. People who choose to wear bicycle helmets will probably be different from those who ride without a helmet: they may be more cautious, for example, and so less likely to have a serious head injury, regardless of their helmets.
horizon wrote:(BTW I'm quite astonished that no such investigations take place and I feel confident that this forum would know of such studies had they occurred).
As noted, there are plenty of them. If only they agreed with one another...
As Goldacre and Spiegelhalter conclude:
In any case, the current uncertainty about any benefit from helmet wearing or promotion is unlikely to be substantially reduced by further research. Equally, we can be certain that helmets will continue to be debated, and at length. The enduring popularity of helmets as a proposed major intervention for increased road safety may therefore lie not with their direct benefits—which seem too modest to capture compared with other strategies—but more with the cultural, psychological, and political aspects of popular debate around risk.
If you want to consider "useful" as being the same as "giving me a significantly reduced risk of a trip to A&E" then what we know is... that we don't really know. The best description I've seen on helmet efficacy changing risk of "normal" cyclists is "about zero, plus or minus error bars". For non-normal cyclists, i.e., sporting, there's not actually much in the way of data. Too few hospital admissions and data not routinely collected as so much is off-road, plus numbers are relatively small.
It's worth noting that they were developed as an improvement on the racer's hairnet (a low benchmark) rather than to do a specific job. They were not designed with the fundamental point of saving commuters or similar from fatal head injury.
Wanlock Dad wrote:I think that the source of the problem is basically the discrepancy between the perceived level of protection and the actual level of protection.
It's my feeling that that's a significant chunk of it.
Often seen riding a bike around Dundee...