Head injuries are a significant risk for cyclists around the world, with biking accidents being one of the most common causes of traumatic brain injuries.

Cyclists are especially vulnerable on the road, lacking the protective barriers found in motor vehicles.

Authorities have been promoting cycling for commuting and recreation by launching campaigns to increase bike use and building bicycle-friendly infrastructure to make cycling safer and more appealing.

Despite these efforts, there has been an increase in the number of cyclists hospitalized due to injuries, and head trauma remains the most common injury. In fact, head injuries contribute to the majority of cycling-related fatalities.

The use of helmets has been widely recommended as an effective measure to reduce the risk of serious head injuries, making helmet use a critical focus for improving cycling safety. But how much do the helmets protect you?

The study

A 12-year study at Oslo University Hospital took a look at bicycle accidents, particularly looking at head injuries, brain surgeries, and whether wearing a helmet made a difference in saving lives.

From 2005 to 2016, 1,543 injured cyclists were admitted to the hospital trauma center, of whom 1,256 had information on helmet use. The median age of the injured riders was 41, and 73% were men. Most crashes (67%) were solo acts, while 27% happened during nighttime when visibility is poor, and judgment can be too, if you know what I mean.

About 54% of cyclists were wearing helmets when they had their accidents. The helmet-wearing riders tended to be a little older, less likely to have serious health issues beforehand, and generally avoided nighttime riding.

When it came to the overall severity of injuries, there wasn’t a significant difference between those wearing helmets and those who weren’t. This gave the study a solid foundation for comparing head injuries with or without wearing a helmet.

The results showed that helmets do indeed provide a big benefit when it comes to protecting your noggin. Cyclists with helmets had a 62% lower chance of getting any kind of head injury compared to those riding bareheaded. The difference was even bigger for serious head injuries—only 22% of helmet-wearers had severe head injuries compared to 38% of those without. That’s almost like a one-in-three versus one-in-five kind of deal.

The protective power of helmets was seen across all age groups, though it wasn’t statistically significant for cyclists over 70. But that could just be because there weren’t many senior cyclists in the sample. Whether it was a solo crash, a run-in with another cyclist, or even a collision with a car, helmets showed they could reduce the risk of a serious head injury—most dramatically in bike-on-bike collisions, with a whopping 94% lower risk.

When it came to brain surgeries—a good sign of just how bad a head injury can get—helmet-wearing cyclists had 64% lower odds of needing such procedures compared to those without helmets. The most common surgeries involved placing devices to monitor pressure inside the skull, draining fluid from the brain, or cleaning up bleeding under the skull.

While fewer helmeted cyclists ended up on the operating table, there was a 1:2 difference in the death rates between those with and without helmets. The 30-day mortality rate was 1.5% for helmeted cyclists and 2.9% for those without helmets, but this difference wasn’t statistically significant. In other words, wearing a helmet might not always be the difference between life and death, but it could certainly mean the difference between "I’m okay" and "I need brain surgery."

The frequency of helmet-wearing varies widely by country. In Norway, 54% of injured cyclists were wearing helmets, which puts it in the middle of the pack compared to other countries. In the Netherlands, for instance, only about 4.4–7.7% of cyclists wear helmets, whereas in Australia, where it’s the law, you’ll find nearly everyone in a helmet. That’s partly because Australians know that if a kangaroo doesn’t get you, a bike crash might.

Studies suggest that helmet laws help boost helmet-wearing rates and reduce head injuries. For instance, if the Netherlands introduced mandatory helmet use, it could save an estimated 46 lives and prevent nearly 3,000 cases of traumatic brain injury each year.

Some people argue that mandatory helmet laws might discourage cycling or make cyclists feel invincible, leading them to take more risks. But there isn’t much evidence to back up this "risk compensation" theory. In fact, helmet-wearers are often more cautious and likely to use other protective gear.

Overall, the study makes a pretty solid case for wearing a helmet. So, next time you’re gearing up for a ride, you might want to think twice before leaving your helmet at home. After all, it’s better to be safe, even if your hair gets a little flattened.

About the scientific paper:

First author: Ingar Næss. Norway
Published in: Acta Neurochirurgica. October 2024
Link to paper: https://link.springer.com/article/10.1007/s00701-024-06294-6