A study
of admissions to Los Angeles County + USC Medical Center
looked at injuries to bike riders over a 3-year period. It found
that 35% of riders injured while wearing a helmet had significant
head trauma, compared with 34% of those not wearing a helmet.
This was a retrospective study, looking at admissions to the
hospital from 2013-2015. 1,454 bike riders were admitted to the
emergency department during that time. 204 (14%) had been wearing a
helmet, and 1,232 (85%) had not. (Presumably, the information was
not available in the remaining cases).
Helmets don't reduce head injuries - study: mechanism of injury
The most common mechanism of injury was a low speed (less than
20mph) collision with a vehicle (44% of all cases); next most
frequent was collision with a vehicle with impact at more than
20mph, where the rider was thrown from their bike (26% of cases).
Falls not involving a vehicle accounted for 23% of cases.
Helmets don't reduce head injuries - study: injuries
The most common injuries were to extremities due to blunt force
(39% of injuries).
There was significant trauma in 26% of helmeted riders, and in 20%
of those without helmets. As mentioned above, significant head
trauma rates were 35% and 34%. 'Major trauma' rates were 16% for
those with helmets, and 7% for those without.
Helmets don't reduce head injuries - study: discussion
In the 'discussion' section of the report, the authors note that in
this study, wearing a helmet did not appear to reduce head injury.
'This paradoxical observation has also been discovered by Kett et
al., who found helmets do not actually reduce bicycle injuries...The
medical literature is divided on the efficacy of helmet efficacy
[sic] and this highlights the need for more study.'
The discussion also states: 'This data found that 70% of all
injured patients were involved in a collision with a motor vehicle.'
Another interesting point shown by the study was that 78% of
cyclists admitted had extremity fractures (which I guess means
fractures of the bones in the hands and feet, and perhaps arms and
legs). Finally, the authors noted a 13% presence of drugs among the
patients, with 'ethanol' the 'most abused drug', but cocaine at 8%
and amphetamines at 6%. There again, this is Los Angeles.
Helmets don't reduce head injuries - study: my conclusions
This is just one study, and the evidence overall on helmet use is
mixed. We can speculate about why those wearing helmets had higher
injury rates. Perhaps it was just a peculiarity of this particular
medical facility and period. Or maybe some of these people put
helmets on because they knew they had to ride on dangerous roads.
That's speculation, but I suggest there are some solid conclusions
we can draw.
- Since the evidence on helmets is mixed and inconclusive, make
your own decision about whether and when to wear one or not (if
you're an adult). It's not a moral imperative. They should not be
made compulsory, as this will reduce cycling rates, and result in
greater ill-health through inactivity and obesity.
- If national and local governments are keen to reduce injuries,
so as to limit health service costs and show people that cycling
is safe, then they should protect bike riders from motor vehicles.
70% of all injuries in this study were from being hit by a car.
Proper infrastructure with physical protection from vehicles will
have the greatest effect. The Dutch know that already.
- Don't abuse ethanol (i.e. get drunk, I think) and ride your
bike.