• uniqueid198x@lemmy.dbzer0.com
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    1 year ago

    I actually think you’ve misinterpreted what I’m saying, unfortunately. The data consistently shows that head injuries are the most common form of injury for all forms of individual transport, that present in hospital. That includes modes where helmets are common like cycling and motorcycling, and modes where they are not common such as walking and driving.

    The data further show that out of all modes of individual transport, cycling results in the least hospital visits per unit distance traveled.

    Further, various studies suggest but can not conclude, that various policies which increase helmet use also contribute to higher rates of hospitalization for cyclists. The data also shows an inverse correlation with unknown cause in populations with lower habitual helmet use and bicycle hospitalization.

    The actual point I would like to make is that the study of bicycle injury and helmet effectiveness is young, and the data are inconclusive at best.

    I certainly don’t want you to not wear a helmet while cycling, but when we talk about public policy, that might be another question entirely. Unfortunately, the received wisdom based on emergency ward studies on the early 80s was itself not comprehensive, and has only become less clear over time.

    • supercheesecake
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      1 year ago

      The data further show that out of all modes of individual transport, cycling results in the least hospital visits per unit distance traveled.

      If we put aside the requirement that, to be meaningfully compared, the different modes of transport would need to be normalised to the number of people participating in each mode of transport, wouldn’t this support the statement that helmets prevent hospitalisation?

      • uniqueid198x@lemmy.dbzer0.com
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        1 year ago

        Well, it shows that either all places in the data set have universal helmet use (they don’t) or that helmet use is not the dominating factor. Further, informing policy, is suggests that it would be better to mandate helmet use for the more dangerous modes such as walking and driving, and focus enforcement there

        • supercheesecake
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          1 year ago

          How do you conclude that walking and driving are more dangerous in terms of head injuries?

          • uniqueid198x@lemmy.dbzer0.com
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            1 year ago

            The article linked at the beginning of this thread lays out a good overview of the available research. This includes causes of head injury hospital visits, over half of which were from driving.

            • supercheesecake
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              1 year ago

              So if activity X has a 1 in 50 chance of injury, and activity Y has a 1 in 500 chance, which would you say is more dangerous?

              • uniqueid198x@lemmy.dbzer0.com
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                1 year ago

                I think I see what you are getting at… We need to look at the rate of injury per use. In traveling, we may want to look at travel times. From the article I mentioned:

                Risk of head injury per million hours travelled

                Cyclist - 0.41
                
                Pedestrian - 0.80
                
                Motor vehicle occupant - 0.46
                
                Motorcyclist - 7.66
                

                Which would you say is more dangerous? Those are probably the ones that should have mandatory helmets laws, no?

                • supercheesecake
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                  1 year ago

                  Do you know what “per million hours traveled” means and how it was calculated? Is it per person, cumulative across the population, something else…?

                  Using my example above, let’s say cycling had a 1:50 chance of injury and driving a 1:500. You’d naturally say cycling is more dangerous. Let’s also imagine on a given day in your city there are 1000 people cycling and 20000 driving (pulling numbers out of my butt, but probably not unreasonable).

                  With the above, the hospital ER would see 20 bike injuries and 40 car injuries per day. I.e. twice as many injuries from cars, even though the chance of being injured is an order of magnitude smaller.

                  That’s mostly the point I was trying to make. And why the details matter.

                  Also another thought on the article: to draw a fair conclusion (apples-to-apples comparison) you actually need to know the bike numbers without helmet. It could be, take the helmets off the cyclists and their injury rate skyrockets towards the motorcyclists.

                  It would certainly be reasonable to expect the head injury rate to go up without helmets on cyclists heads.

                  • uniqueid198x@lemmy.dbzer0.com
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                    1 year ago

                    Yes, it’s calculated across the population, it’s an epidemiological study. That is, for every million hours the population as a whole spent driving, there where 0.46 head injuries (as an average). For every million hours the population as a whole spent cycling, there were 0.41 head injuries. This was before the helmet law went in to place. This means that, on a time sent basis, you where slightly more likely to receive a head injury in an automobile than on a bike. Your math would be correct, but the probabilities you listed are not those the study found.

                    Meanwhile, this study found that whole helmet use in Victoria and NSW increased from roughly 30% to roughly 75%, the proportion of head injuries only dropped by 13%. On the other hand, ridership declined after the helmet laws.

                    Raising more questions, during the same time period, the proportion of head injuries amongst pedestrians also declined by about the same amount, indicating that helmets may have partial or no responsibility for the decline.

                    Again, the available data suggests that without helmets, the rate of head injury stays in line with cars and walking, and with helmets, the rate stays in line with cars and walking.