Bicycling magazine recently republished an article with the clickbait headline “It’s Okay If You Don’t Wear a Bike Helmet”. Clearly, the implication was that helmets are not really very useful.
The article went on to talk about safer bicycling infrastructure – but it doesn’t have to be an either/or situation. Should we stop designing crumple zones into cars because we shouldn’t crash them in the first place? Should we toss out airbags, seatbelts, and carseats for kids? None of those are useful when nothing goes wrong. We work for the best and plan for the worst.
What does the evidence say about helmets? And how good is that evidence? A quick review: when we look at evidence, we consider “levels of evidence”. Different authors define those differently but, generally speaking, the highest level of evidence is a systematic review of randomized controlled trials (Meaning, for the non-scientists among you: looking at not just one, but many studies of the same phenomenon; and not just observing what happens in retrospect, but planning a test, assigning people randomly to groups, and looking at what you are studying in relation to a control group. A few definitions: randomized – people are assigned to one of two or more groups randomly, so that the groups should look the same; double blind – neither the participant nor the observer knows which group the participant is in; placebo-controlled – the group that doesn’t get the test intervention gets something that looks the same but should have no direct effect on the condition studied.) Expert opinion is the other end of that scale.
Randomized controlled trials are not always possible. The article “Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials” (Smith & Pell, British Medical Journal, 2003) points out the difficulty of testing some hypotheses. They concluded:
“As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.” (Smith & Pell 2003)
Further, Yeh, et al (BMJ,2018) in the PARACHUTE trial, conducted a randomized (but not blinded) study of parachute use in “Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial”. Their outcome measures were death and ISS (Injury Severity Score). Come to my workshop for an explanation of ISS. They concluded:
“Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention. However, the trial was only able to enroll participants on small stationary aircraft on the ground, suggesting cautious extrapolation to high altitude jumps. When beliefs regarding the effectiveness of an intervention exist in the community, randomized trials might selectively enroll individuals with a lower perceived likelihood of benefit, thus diminishing the applicability of the results to clinical practice.” (Yeh, et al, 2018)
We can extrapolate from the above studies that we cannot conduct an RCT (Randomized Controlled Trial) to truly test the efficacy of bike helmets. We can also conclude that careful reading is important, lest we draw the wrong conclusions, or accept the conclusions drawn in articles in the popular press about the study .
So what do we have? Olivier and Creighton, writing in the International Journal of Epidemiology (2016), reviewed thousands of studies. 40 met the inclusion criteria and were included in a meta-analysis, with data from >64,000 injured bicyclists. For those who only like to read abstracts, we’ll cut to the chase:
“Bicycle helmet use was associated with reduced odds of head injury, serious head injury, facial injury and fatal head injury. The reduction was greater for serious or fatal head injury. Neck injury was rare and not associated with helmet use. These re- sults support the use of strategies to increase the uptake of bicycle helmets as part of a comprehensive cycling safety plan.” (Olivier & Creighton, International journal of Epidemiology , 2016).
For a few nuggets from that study: “In a recent Australian study of linked police and hospital data for cyclists in motor vehicle collisions, 34% of hospital-admitted cyclists had a head injury and 15% had a serious head injury.2 In a coroner’s review of cycling fatalities in Canada, 55% of deaths were caused by head injuries.3” Also note that “neck injury was rare and not associated with helmet use.” One of the objections to helmets I have seen raised (by both bicyclists and motorcyclists) is that they think they increase the risk of neck injury. Olivier and Creighton found no such correlation.
Looking at individual studies cited, the risk reduction for head injury attributable to wearing a helmet was 85% in one study and about 30% in another (though 70% for severe injury as assessed by the AIS (Abbreviated Injury Scale). Come to my workshop for an explanation of the AIS.
The argument is often made (and is made in the Bicycling article) that wearing a helmet leads to riskier behavior. This is a phenomenon actually studied with all safety devices. Some studies assert “reduced cognitive control” while wearing a helmet. Several of these analyze the behaviors of subjects playing computer games, in which the “risk” is theoretical in the context of playing a game. One which did look at bicycling behaviors noted that male cyclists rode at a slightly higher speed when wearing a helmet. This was not true of female cyclists. It should be noted that the helmeted riders rode at 19.2 km/h (a whopping 11.9 mph) compared to 16.8 km/h (10.4 mph) and that anyone who had previously worn a bike helmet was excluded from the study.
Anecdotal evidence is at the bottom of most evidentiary scales, if included at all. Your author once crashed at about 1 mph (stopping at a stop sign, hitting a patch of ice with front wheel, and falling to the left side, striking the head). It happened so fast that I remember hearing my head bounce off the pavement at about the same time that I realized I was going down. The impact cracked the helmet but caused no ill effects. It was only after trying to get up (and slipping) that I was aware of the ice. The speed of travel did not appear to mitigate the effect. It might be noted that crashing at a higher speed could result in reducing the direct impact of head to pavement (as you could hit it sliding, rather than directly, and the head might not be the first body part to hit). Think about falling directly onto pavement on your head at zero speed. Does that sound harmless?
I grew up in the pre-helmet era. (Truth be told, I remember the first time we got a car with seat belts, and I also remember children’s car seats as being entertainment devices, not safety devices. Our car seats were made of aluminum, lightly padded and covered in vinyl. The belt was a ¾ inch wide vinyl strap. There was a steering wheel with a horn button.)
I moved to California as an adult in 1984. Some people wore helmets out there. Virtually no one did when I left Wisconsin, but they were widespread when I returned. (Let’s just agree to dispense with the “I didn’t have ‘x’ when I was a kid, and I survived…” argument. See paragraph two.)
The first helmets were essentially leather “hairnets” worn by some bike racers. The first consumer bike helmets were hot and heavy. They were worn only by nerds. The Bell V-1 Pro, introduced in the mid-80s, was the first helmet that offered protection and caught on widely (and note that it looks like a sturdier version of the leather hairnet – that was not an accident).
I was riding in the mountains when I came up on a downhill turn, sharper than it first appeared. My bike was in need of a headset at the time, so it chattered under hard braking. I scared myself on that turn and went straight to a bike shop. I dropped off the bike for a new headset and bought a Bell V-1 Pro. I have not ridden without a helmet since then.
Who am I to pontificate about helmet use? So far, I’d say there has been less pontificating and more reviewing evidence. That being said, it is probably clear by now that I come down in favor of helmets. (Especially if you read the title.) We have discussed infrastructure and safety here before. (And will again in a post very soon – written before this one but awaiting final revisions.) Not crashing is better than crashing. Prevention beats mitigation; but we will never prevent 100% of crashes and if you’re the one crashing, despite your best efforts, you might want that mitigation. Very few of us expect to crash. But that’s how I make my living.
I have spent the past 20+ years working in a large teaching hospital. I have spent most of those in a Level 1 Trauma Center. While some people plan to be in a hospital (for elective surgeries) or spend a lot of time in them (for management of chronic conditions), most of the people I work with had no intention of winding up under my care. I have learned, over the years, what injuries are likely to result with and without lap belts, shoulder belts, and airbags. And I learned why school bus drivers used to yell at you to keep your hands inside the bus. I have seen the arms that got trapped under cars and dragged along the pavement, and helped those folks with their rehab. (I no longer rest my arm on the windowsill when I drive, but that’s just me.) I know what you’re likely to break falling from a ladder, the difference in what young and old people tend to break in similar falls. I also have seen that people without helmets tend to have worse head injuries than those with helmets, that other injuries are pretty similar (mostly clavicle and rib fractures), and that those with head injuries tend to fare worse in both the short- and long-term.
We can also look at it from a business perspective – a risk/benefit analysis.
*Risk of not wearing a helmet – brain injury, death. Benefit of not wearing a helmet – better hair or the feeling of the breeze in your hair (probably not both).
*Risk of wearing a helmet – matted hair or not looking cool. (Some would argue that you have a greater chance of doing something stupid, but I’d say alcohol is the hands-down winner for that risk.) Benefit of wearing a helmet – reduced chance of head injury, bigger reduction in the risk of serious head injury or death.
You may consider other risks and benefits, but I think it would be hard to come to a different conclusion.
While we’re at it, how often do you see families out together; the kids are wearing helmets, the parents are not? What message does that send to the kids? The way I see it, you are telling your children “helmets are kids’ stuff.” We know most kids want to feel grown up and many want to be like their parents. You can bet that, as soon as possible, kids will ditch the helmet to feel grown up. I see many middle school kids using helmets as handlebar decorations. If you are a parent and ride a bike, think about helmets – are you putting helmets on your kids because other parents might yell at you if you don’t? Are you doing it because you think helmets will make them safer? If the latter, then why don’t helmets make you safer? If the former, why don’t you have the guts to stand up for your convictions? (And exactly what are those convictions? Do you think you are battling courageously the nanny state?)
So you can take my word for it as an expert, or as someone who has personally experienced crashing and hitting my head, or you can read the literature. In all cases, I think you’ll find that you’re better off with a helmet than without. (And maybe you’ll find one story of someone who was somehow injured by wearing a helmet. An early argument against seatbelts in cars was that you would get trapped in a burning car and die because you wore a seatbelt. Yes, that has happened; but less frequently than people have been thrown from cars – through the windshield, a window, the sunroof – and killed because they weren’t wearing a seatbelt; which is not to mention the multitude of injuries sustained by those flying around in a rolling car even if they don’t fly out through an opening.) Since most of you will not crash and hit your head, you can play the odds if you choose; but then we’d have to look at the public health consequences and the societal costs of your choice. That would be fodder for another post.
(Complete citations available on request – but you oughta be able to find the articles if you try, and have access to PubMed.)