Leave it to science to confuse you with data about what you just know is absolute fact.
This time it regards the claim bike helmets save lives. Every cyclist reading this falls into one of two groups:
- The group which has had a bad crash and is convinced that “but for that helmet, I wouldn’t be alive today.”
- Or the group who knows someone in the previous group who proselytizes for helmets because “but for that helmet, I wouldn’t be alive today.”
Many non-cycling friends of cyclists would also fit the latter category. Given that cyclists are encouraged to wear helmets “because it could save your life,” it’s only logical to assume in the wake of a crash that the helmet worked.
And it could well be true that it did. The person making the claim could really be one for whom the helmet was a life saver.
But scientists in California went looking for objective data on how much of a difference helmets truly make, and what they discovered proved surprising.
After combing through the medical files of 1,454 people treated for injuries after bicycle accidents in the Los Angeles area, this is what they found, according to paper published in January in the International Journal of Advanced Research in Orthopaedics:
“Overall, 292 patients had severe trauma. Significant head trauma was diagnosed in 142 patients (10 percent). The prevalence of significant head trauma was 35 percent in the group of patients with helmets and 34 percent in the group without helmets. It should also be noted that the prevalence of all significant trauma was 26 percent in the group of patients with helmets and 20 percent in the group without helmets.”
The small difference between head trauma in the helmeted and unhelmeted groups is statistically meaningless. Much the same could be said of the percentage difference between the significant trauma suffered by helmeted and unhelmeted riders, though the difference there is approaching significance.
That could be due to a couple of things. Helmets could be encouraging cyclists to ride faster and/or take more risks, or helmets could be altering the behavior of motorists.
Other studies, Dr. C. Thomas Vangsness Jr. and colleagues note in their Los Angeles examination, “found that when driving near a helmeted bicyclist, drivers tend to drive closer than when driving near a non-helmeted bicyclist. This may have to do with the driver believing a bicyclist is more protected when wearing a helmet and may lead to more traumatic injuries for helmeted cyclists.”
The real issue
But the key part of the study might have little to do with the hot-button subject of helmets.
“The medical literature is (already) divided on the efficacy of helmet efficacy,” the authors note. Even if the self-appointed safety police of modern society are prone to see helmets as the simple solution to saving lives, the belief in helmets as the silver bullet has been questioned by some previous studies.
Which is not to say a helmet won’t help you. Helmets do offer some protection in crashes. There is no denying that.
As Alyssa DeMarco and Benjamin Elkin observe at MEA Forensic, an engineering firm involved in safety testing, “helmets can attenuate impacts and reduce the forces transmitted to the skull and brain during an impact. Helmets, however, do not guarantee protection in all impact conditions and some helmets provide better injury protection than others.”
The best advise for cyclists might be that now given to downhill skiers, who are involved in a sport where helmets have only recently become regular gear: Wear a helmet, but ski or snowboard like you’re not wearing it.
That’s advice easier to give than to practice, and it is more applicable to skiing – where dangers are fixed – than cycling where the biggest dangers are moving.
“The most common mechanism of injury was collision with a motor vehicle without being thrown off (44 percent) followed by collision with a motor vehicle and subsequently being thrown off (26 percent),” the California researchers reported.
In other words, 70 percent of the injuries came from collisions between motor vehicles and bikes.
The study did not attempt to quantify the number of the cyclists on the roads in Los Angeles, but did note that “bus ridership has been associated with increased bicycle use. (And) Los Angeles is different from all previously studied major urban areas because of its large bus ridership and its remarkable road traffic congestion.
“The seriousness of the issue of bicycling injuries has been underscored by the recent implementation of legislation that mandates drivers in the state of California to maintain a distance of at least three feet from bicyclists on the road.”
“In the past five years alone, more than 180 riders in the metropolitan area have been killed by people driving motor vehicles,” Peter Flax wrote in the story below that headline. “During the last three years that national crash data has been compiled (2014-2016), only three U.S. states have seen more cyclist fatalities than just L.A. County—Florida, New York, and California as a whole.”
The city has begun to take notice. CBS Los Angeles noted an effort to upgrade and improve city bike lanes after paying “out more than $19 million in lawsuits to settle cases involving cyclists injured or killed on city streets” in 2017.
The authors of the bike helmet study, which used data gathered at the Los Angeles County-USC Medical Center, said they were in a unique environment for such a study.
“This study differed from the previous literature as it sought to
investigate variables of bicycle injuries specifically in one of the world’s busiest emergency rooms,” the authors wrote.
Their main finding was not surprising: bike accidents caused a lot of broken bones.
Of the 1454 bicycle injuries in the LAC+USC registry we reviewed, 78 percent had fractures,” the wrote. “The 1140 fractures, including bones of the upper and lower extremities, are consistent with a previous study….
“Cycling on the shared road has previously been found to increase the
chances of injury….In Hong Kong, cycling injuries on public roads (with cars) were more severe than those occurring on cycling tracks.”
The study could be read to indicate that where you ride has a lot more to do with the likelihood of a suffering a serious injury than what you wear on your head.
The wild cards
What the study doesn’t include is much in the way of demographics to define those seriously injured in bicycle accidents other than to note a quarter were age 18 or younger.
But the overall low use of helmets – 14 percent – among the almost 1,500 injured cyclists might indicate a sample weighted toward lower-income Los Angeles residents who tend to live in neighborhoods with lower quality cycling infrastruture and other issues, as Bicycling writer Dan Koeppel pointed out in a lengthy, 2015 story about pedaling the city’s poor neighborhoods.
A 2012 study in Winnipeg, Mantibou, Canada, found helmet use above 50 percent in one of the city’s ritzier suberbs. Use fell to half that in poor neighborhoods.
Income could, as in many previous studies, be skewing the data in one direction or another, although a lot of other studies have found helmets in general over-rated.
Among those who can afford resort skiing or snowboarding, the National Ski Areas Association (NSAA) now reports 80 percent wear helmets. Almost 60 percent of resort skiers are reported to have incomes of $100,000 or more.
The huge increase in ski helmet use since the 1980s has lowered the number of head injuries among this group by only about about 1 percentage point, according to NSAA data. Experts have attributed the lack of a more significant reduction to helmets encouraging skiers to ski more aggressively.
The average fatality on the slopes in Colorado is an experienced, 37-year-old “male skier wearing a helmet and (who) loses control on an intermediate, groomed run and hits a tree,” according to the University of Colorado.
“Helmets protect at lower speeds (less than 12 mph) and skiers or snowboarders are typically hitting trees at 25-40 mph.”
Ski helmets are sturdier than bike helmets and less debated these days, possibly because they’ve taken the place of the wool hat for keeping heads warm. And they are an upgrade on the wool hat; many now come outfitted with first-class sounds systems for listening to your favorite music.
Criticism of bike helmets has focused largely on the idea that best way to make cycling safer is to put more cyclists on the roads – so drivers are constantly aware of unprotected road users – than to put helmets on their heads – which still leaves their bodies exposed to crushing blows from cars.
The new study out of California is sure to stir more debate.