Comment by dvdkhlng | Hacker News Reader

Comment by dvdkhlng | Hacker News Reader

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I think people are overestimating the merit of normal bicycle helmets. I think the actual effect is something like this ([1]):

> The most reliable estimates indicate that at speeds of up to 20 km/h helmets reduce the risk of head injury by 42%, the risk of brain injury by 53%, and the risk of facial injury by 17%, whereas they increase the risk of neck injury by 32%. These estimates are partly based on research carried out in countries like the United States and Australia, where standards for bicycle helmets are stricter than they are in Europe and can offer protection at higher impact speeds.

In wikipedia [2] I find this quote: "This effect is statistically significant in older studies. New studies, summarised by a random-effects model of analysis, indicate only a statistically non-significant protective effect"

And to the parents around here, make sure your kids know when to not wear a helmet (choking accidents [3])

[1] https://www.helmets.org/stats.htm#effectiveness

[2] https://en.wikipedia.org/wiki/Bicycle_helmet#Effectiveness

[3] https://en.wikipedia.org/wiki/Bicycle_helmet#Accidental_hang...

Bicycle helmet safety is one of those things that will never be accurately covered by statistics, because most cases where the helmet did its job don't end up in the stats as there are no significant injuries.

In the only serious bike accident I have been involved in, the victim would have walked home on their own feet had they worn a helmet. Instead, a fall from the bike on low speed and hitting their head on tarmac ended up in serious head injury and 6 months in the hospital.

Had they walked home, it would have not ended in the stats.

+1 I once landed head first on a mountain bike going downhill. The helmet literally exploded in a million pieces. Walked away home unharmed. Didn't go in the stats.

It was my third time snowboarding and the snow was compact and icy. I was going relatively fast for my control. Caught an edge and fell on my back with my head doing a whiplash. I was probably unconscious for 10 seconds or so. Lay there for another half a minute to gather myself and stood up. Checked the helmet, there was a massive crack. Checked head for bleeding. No bleeding! I walked away and went to the car to get some rest.

The helmet literally saved my life.

I wonder if the neck injury thing is just because a "lesser than" injury is actually getting reported? I haven't seen anything in the article about it, but for example iirc there was this hullabaloo about motorcycle helmet data indicating an increase in back injuries for helmet-wearers, until someone pointed out that dead-on-site riders would be reported as simply "dead," with their injuries unaccounted for.

The helmet sticks out a couple of centimeters and can increase torque if you don't fall straight down. It's plausible that it can cause more serious neck injuries.

I've always wondered why they're designed that way -- it looks like it's asking for trouble.

A flat shell on front and back would not absorb a hit well if at all - and those are relatively common accidents.

Typical fall has the first contact either direct front or direct back based on kinematics which means they're subject to most force. Falling on side of head is somewhat more rare. Falling on top of the head is rare.

That seems very likely. There was a similar effect for armoring airplanes in WW2, and giving soldiers helmets before then...

At least we usually figure it out. "More injuries because less deaths" is simple enough, I guess.

The GP was most likely referring to motorcyclists riding without helmets.

> only a statistically non-significant protective effect

I don't think this phrasing makes sense. A particular study may find a positive effect but with p>0.05, but that depends as much on the size of the study as on the effect itself.

If I'm choosing I'd rather injure my neck than my brain.

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