Saturday, November 28, 2015

BMJ Article Finds No Benefit to Bicycle Helmet Laws

I have read countless scientific studies since embarking on this bike helmet discovery journey more than ten years ago, so when I find one that is readable, concise, and easy to understand, I just have to share. This one, recently published in the British Medical Journal (BMJ), clearly shows the important finding that bike helmet laws have little if any effect on head injury rates.

To give you an idea of how thorough the study is, here is an excerpt:

“…Helmet legislation was not associated with hospitalization rates for all injury or traffic-related injury causes. We separately examined potential associations for each body region expected to be protected by helmet use (brain, head, scalp, skull or face; brain; head, scalp or skull; face) as well as for the neck which, in some studies, has had elevated odds of injury with helmet use. 7 8 There was variation in helmet use with helmet legislation, and this may have been related to municipal by-laws mandating helmet use within some provinces or territories without helmet laws (table 3). We therefore also examined the relationship between hospitalization rates and helmet use proportions in the strata, and again did not find the expected protective effect. Studies among those injured in a cycling crash consistently show lower odds of head, brain or face injuries among those who wore a helmet,7 8 though the potential for uncontrolled confounding in observational studies of a health behaviour suggests that confidence in the effect estimates should not be unquestioning.47 Before–after studies of the impact of helmet legislation have shown weaker and less consistent effects. Some have found reductions in brain or head injuries of 8–29% related to legislation,10–13 whereas others have found no effect for some or all outcomes.9 11 13 Differences may be attributable to study design features including location, the selection of a control group unexposed to helmet legislation, whether baseline trends in injury rates were modelled, and whether surrogates were used for cycling rates and if so, which ones. Our study compared bicycling hospitalisation rates across jurisdictions rather than within a jurisdiction before and after legislation, and used exposure-based denominators to control for differences in cycling rates.”

To read the whole article, click here. Great stuff.


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