Over one-fifth of injured US adult cyclists were not wearing a helmet

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Mike Sales
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby Mike Sales » 16 Sep 2019, 12:13pm

The writers of this study seem not to have looked at the possibility that those cyclists who choose not to wear a helmet may have a tendency to ride differently and in different places from more risk averse riders.
This mistake has been made before.
Last edited by Mike Sales on 16 Sep 2019, 2:53pm, edited 1 time in total.

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mjr
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby mjr » 16 Sep 2019, 12:23pm

That analysis's conclusions seems very biased. It reminds me of misinterpreting "20% of sick days are taken on Fridays" and concluding "workers are using sick days to steal long weekends". Can someone check my quick-look reasoning below, please?

I think you can calculate from the figures in the first-linked report (20.6% of 81.1% male plus 28.3% of 18.9% female) that 22.06% of the study database used helmets. Anyway, the second link says "less than half of children and adults in the United States report wearing a helmet while riding".

Taking those at face value and assuming sufficiently random distribution of helmet usage (very debatable), if 78% of those injured were using helmets but helmets are used by less than 50% (to take the weaker claim), they're significantly over-represented.

In other words: that report suggests helmet users seem more likely to be injured than non-users.

So save yourself! Helmets: just say No!

Edit to add: I was suspicious about that 22.06% so looked again. The headline is technically accurate, but misleading. The 22.06% is the helmet use rate of those injured, so 78% are not using helmets, which is "over one fifth" but by quite a lot... and broadly proportional to reported usage rates. So without a more precise estimate of usage rate, this report is not saying much. Smoke and mirrors...
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RichK
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby RichK » 16 Sep 2019, 12:59pm

Unless I'm missing something they seem to be saying:

21% of men reporting with head injuries were wearing helmets
next to
21% of men use helmets

so even at this simplistic level, suggests no benefit of doing so.

[Edit]
So I take a quick look at the longer text

Not surprised to see them citing Thompson, Rivara & Thompson.

Enough said
[/Edit]

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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby Vorpal » 16 Sep 2019, 2:46pm

Yet another hospital study which has all of the problems that hospital studies have.

OK, it looks like helmet wearers had shorter hospital time than non wearers, but the data about helmet wearing in the population is too poor to draw any conclusions. For example, they look at helmet wearing rates for those admitted to hospital by ethnicity, but, not in the population.
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Wanlock Dod
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby Wanlock Dod » 16 Sep 2019, 9:39pm

The analysis seems to have been done on data for head and neck injuries without any apparent mention of whether that was a choice or a constraint of the dataset.

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hatless
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby hatless » 17 Sep 2019, 7:58am

Doesn't the obsession with 'race' seem bizarre! I suppose that in some branches of medicine they are finding distributions of illnesses that reflect global genetic variation, but would they really expect it to be relevant in head injuries?

sizbut
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby sizbut » 17 Sep 2019, 6:23pm

Race does seem bizarre but a kind interpretation would be they just used everything they had for free (likely age group, sex, race) just for the sake of it rather than any planned reason or intent.

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Cunobelin
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby Cunobelin » 17 Sep 2019, 7:34pm

These studies continue to be more about reinforcing the investigators bias about cyclists than anything about reducing head injury.

Cohort studies always show that far more head injuries occur in pedestrians... yet no studies about their head injuries, or preventing them

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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby Vorpal » 18 Sep 2019, 10:27am

sizbut wrote:Race does seem bizarre but a kind interpretation would be they just used everything they had for free (likely age group, sex, race) just for the sake of it rather than any planned reason or intent.

In the USA, helmet wearing and cycling behaviour are very different among blacks and whites. This was not accounted for in the Thompson, Rivara, et al. study. And why it could also show that a helmet prevented other injuries than just head injuries :roll: I'm not sure how much of the differences are accounted for by economic conditions (i.e. poor whites likely exhibit behaviours in this regards that are more similar to blacks than middle class whites), education, culture, etc.

Also studies in the USA are often racially biased, so if they don't say something, folks who are conscious of the bias, will assume it is there.
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Cunobelin
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Re: Over one-fifth of injured US adult cyclists were not wearing a helmet

Postby Cunobelin » 18 Sep 2019, 8:49pm

Lets face reality, hospital Stay in the US is about MONEY!

It is well proven that Ethnic minorities in the US are less able to afford healthcare

Yet another confounding fact sacrificed on the Altar of biased Helmet Research