Kim Malcolm talks with Dr. Frederick Rivara about whether the increasing popularity of bike sharing has led to more head injuries. Dr. Rivara is professor of pediatrics at the University of Washington.

This interview was inspired by a question from KUOW listener Patricia Boiko.

Has the rising popularity of bike sharing led to more head injuries?

Rivara: We recently looked at about 80 people who were treated for bike injuries at Harborview Medical Center. We found that of those 80, only three were bike-share related.

Why do you think that is?

First of all, I don't want to leave your listeners with the idea that they shouldn't wear helmets. Helmets prevent 85 percent of head injuries.

But with bike shares, it's a combination of factors. I think the bikes are a bit clunky, and they're slower than the typical 18-speed bike that most of us have at home. And I think the people riding them don't want to go fast.

Is that reassuring to you in some way?

Well, there aren't that many people who are being injured on bikes to begin with. So it is reassuring that there's not an increased number of head injuries.

But we’re still in the early stages of bike sharing. I think we're going to see more and more people using bike shares. And as that use increases, we’re going to see more head injuries, unless helmet use increases.

Another KUOW listener wrote to us and said bike share users not wearing helmets is a public health problem. Do you agree?

It is. We've been working at the Harborview Injury Prevention Research Center for about 25 to 30 years on getting people to be safer. One of the first projects we tackled was getting people to wear bicycle helmets. We did the research to show they're very effective, and we did a public education campaign to get people — particularly kids and their parents — to wear helmets. And that was successful.

Unfortunately, I feel with the bike share program, we’re taking a step backwards. Head injuries are a big public health problem. One of the things your listeners should realize is that no physician can reverse what happens with a brain injury. We can't heal the brain. We can't fix the brain. It has to heal itself. The best way to treat a brain injury is to prevent it from happening in the first place.

What’s the solution to get more people to wear helmets?

I think educating people about the need to wear helmets is critically important. I don't think the city is going to require bike-share companies to provide helmets. That's difficult with these non-docking bikes that we now have in the city.

Electric bikes are becoming more popular in Seattle. What's your concern there?

Electric bikes may be a whole different situation. They’re able to go faster than bike share bikes, and I’m worried about these bikes increasing the risk of head injuries.