It's all bike safety today! This is Healthcare Triage News.

Today's first story come from an interesting new paper in Health Economics, it's called Effects of Bicycle Helmet Laws on Children's Injuries.
Look, lots of people ride bikes, lots of kids ride bikes, but they can be dangerous. In 2009 alone, bike accidents led to 782 deaths and more than 518,000 visits to emergency rooms in the United States. Kids ages 19 and under account for 57% of those injuries. A lot of the danger is due to head injuries, especially in children. In recent decades we've done a lot to promote the use of bike helmets. We've done such a good job that not wearing a bike helmet is only second to smoking cigarettes in public in arousing the wrath of my children. Even so, according to this paper, less than half of riders are using helmets regularly nationwide. Some places have implemented laws to make their use mandatory. Do those laws work to reduce head injuries?
This study examined the association between bike helmet laws and head injuries. But they also looked at the effect of bike helmet laws on bike-related non-head injuries, and injuries from other wheeled activities not affected by helmet laws like skateboards and inline skates. They found that in kids aged 5-19 years, helmet laws were associated with a 13% reduction in the incidence of bike-related head injuries. But they were also associated with a 9% reduction in bike-related non-head injuries. This means that wearing a helmet either protected the body as well as the head or made people just ride more safely in general. Or that bike helmet laws worked by getting fewer kids to ride bikes. Now the researchers also saw an 11% increase in injuries from other wheeled activities. This would support the idea that some kids just started riding other devices and still kept getting injured.
Now it is still possible to look at these results and argue that bike helmet laws and campaigns lead to safer riding practices, and that has reduced injuries in bikes overall. The data are consistent with that story. But they're also consistent, and perhaps more so when adding in the increase in other wheeled injuries, with the story that bike helmet laws merely get fewer kids to ride bikes and move to other activities where they're being injured just as much. This isn't to say that bike helmets don't work, and I don't know what the answer is to this whole law problem; I don't think this will stop me from getting my kids to wear helmets when they ride their bikes no matter what the laws are in Indiana. For the record, I also make them wear their helmets when they ride their scooters - it's the pediatrician in me. But I do hope people look into this further; we don't want to think we're solving the problem, especially with laws and regulations, if we're really not.

Speaking of bike helmets, someone on Twitter sent me a link to another study called Safety Effects of Permanent Running Lights for Bicycles: a controlled experiment. This was actually a randomised controlled trial of putting permanent or daytime running lights on bicycles. It was what we call cluster-randomised, or where they do it in groups. And over the course of the year, the incidence of accidents for those with the running lights was 19% lower. The incidence of multiparty accidents with injury to the participating cyclist was 47% lower. The study was published in 2013, how do I not know about this? How is this not common knowledge?
Policy sometimes baffles me. This was a randomised controlled trial of almost 4,000 participants. They found a real reduction in an important outcome. There are no randomised controlled trials for bike helmets, because people argue that it would be unethical to do so. In fact I think most of the research is case-controlled. Don't get me wrong, I understand why that is and I'm not recommending that people stop wearing their bike helmets. The odds ratios for preventing head injury are compelling in those studies. But we have a randomised controlled trial here for another intervention with a real reduction in accidents, why aren't we acting on that?