Registre du Rhone: some bike helmet datas from France

September 5, 2014

Below we provide mainly some number coming from [1], using a data base; the “registre du Rhone” (Lyon district, France); recording detailed information for 14 478 cyclist victims of road accident in the Rhone county (France). The data under studies have been collected from 1996 to 2007. The level of detail is very high compared to some other data base, and they can help to clarify the helmet debate:

see wikipedia for the AIS and IIS definition and meaning

Injured Body part among cyclists
reported numbers are only for cyclist where the helmeted/unhelmeted status is known

helmeted 1461 unhelmeted 5620 helmeted 1461 unhelmeted 5620
Body region %yes %AIS3+ %yes %AIS3+ yes AIS3+ yes AIS3+
head 16,6% 1,0% 19,5% 2,3% 242 15 1095 128
face 18,3% 0,1% 24,3% 0,2% 268 1 1367 9
neck 3,3% 2,7% 0,0% 48 0 152 1
Thorax 9,6% 1,8% 6,3% 1,0% 140 26 355 55
abdomen 3,9% 0,1% 3,6% 0,2% 57 2 200 14
spine 7,5% 0,3% 5,0% 0,1% 110 5 281 8
Upper Extremity 53,5% 3,2% 44,7% 3,4% 781 47 2513 189
Lower Extremity 33,7% 1,8% 31,2% 1,9% 493 27 1751 107
skin 17,8% 15,2% 260 0 857 0

This table shows that the helmeted cyclist are less often severely injured to the head, less often injured and seevrely injured to the face. But they are more often injured and severely injured to the Thorax and spine, and more often injured to the upper extremity. This suggesthelemeted cyclist get involved in more severe accident. 2 reasons can be advanced for it

    • Helmeted cyclists have a different cyclist practice that non helmeted one (that relate to the infamous MAMIL)
    • There is a risk compensation at play along helmeted cyclist

the effect of it is to give an over estimate of the helmet efficiency

The figure below illustrates the % of head injuries oberved for injuried cyclists with an helmet and without:

The bike helmet seems to have no significant effect at reducing superficial head injuries but it reduces the risk of severe head injury (AIS3+) by 50%. However such severe head injuries represent less than 2% of the total cyclists injuries

So we are looking at a global effect of 1%, but severe head injuries can have long term disabilities consequence, so a reduction by 50% of severe head injuries could be considered a worth endeavour:

Below a more detailled view of the head and face injuries specificities:

Head or face Injuried cyclist: type of lesion according to helmet wearing or not

Helmeted 238 Unhelmeted 1078
lesions N = % N %
Unconsciousness without additional descripted lesion or head trauma without further indication 194 73,5% 668 49,3%
skin lesion 43 16,3% 459 33,9%
brain 21 8,0% 150 11,1%
skull 6 2,3% 65 4,8%
little brain 0 4 0,3%
nerves 0 4 0,3%
brainstem 0 2 0,1%
Destruction skull and brain 0 2 0,1%
Total 264 100% 1354 100%

In despite of a pretty huge database, significativity is not reached on many lesions types.

According to [1], Among the 222 cyclists injuried to the skull or its content

  • 30 are dead
  • 42 will have severe heavy brain disabilities (IIS3) – that represents 0.3% of the injuried cyclist
  • 146 will have light brain disabilities – that represents 1% of the injuired cyclist

The effect of the helmet on long term disabilities seems to be measured on a very small cohort:

unhelmeted 35 helmeted 3
fatalities 15 0
%fatalities among total injuried 0,3%
%fatalities among head injuries 1,4%
Severe head disabilities (IIS3+) 20 3
% Severe disabilities among total injuried 0,4% 0,2%
% Severe disabilities among head injuried 1,9% 1,3%
% Other severe disabilities in addition of severe head disabilities [10] 19,8% 21,4%

Again, we don’t reach significativity to be able to conclude that a “bike helmet saves life”, but it could well reduce significantly the risk of severe head disabilities. The number could suggests 50%, but again with very little confidence.

In anycase, the effect is measured in tenth of 1% of the total injuries: the absolute number of victim is very small.

How bike injuries compare to other transportation mode?

When involved in an accident, cyclists have the lowest fatailities rate compared to other individual transportation mode. They have also the best chance to survive an accident without long term disabilities. Urban cyclists are even much safer than rural or suburban cyclists:

Cyclists
Injury severities Uurban 6584 Rural 1726 0-10years 3364 Pedestrians 10131 car 53151 Mopette Motorbike 21831
MAIS 1 63,7% 53,7% 72,5% 60,4% 81,6% 61,7%
MAIS 2 28,7% 35,3% 22,4% 24,7% 13,4% 27,0%
MAIS 3 5,8% 7,9% 4,2% 10,0% 2,8% 8,6%
MAIS 4 and 5 0,9% 2,0% 0,3% 2,3% 1,0% 1,5%
fatalities 0,6% 0,8% 0,1% 2,6% 1,2% 1,1%
no disabilities 78,4% 73,8% 88,2% 66,1% 55,3% 73,7%
light diabilities (MIIS1-2) 20,2% 23,8% 11,1% 29,6% 42,8% 23,8%
severe disabilities (MIIS3-6) 0,6% 1,2% 0,2% 1,6% 0,7% 1,3%

When urban cycling is considered alone, helmeted cyclists are observed to have 20% less chance to be severly injured that non helmeted one, whenever involved in an accident, however significativity is not reached [1].

The figures below eventually help to compare the different pattern of injuries, according to transportation mode, and eventually relativize the impact of a bike helmet on the total number of both severe head injuries and severe disabilities.

AIS4plusandTransportationMode

Injuries type according to transportation mode (from [2])

Long term severe disabilities type according to transportation mode (from [2])- head injuries represents ~60% of the long term disabilities fro both pedestrians and cyclists

those figures provide absolute numbers for the Rhone district (1.7Millions) inhabitant for years 2007-2010…
Even if a bike helmet is able to reduce the severe head injuries and disabilities, by 50%, the saving in term of public health could be relatively insignificant but the more generalized economic cost can be real: It has became clear that an helmet legislation is counterproductive, but even promotion campaigns in favor of bike helmet could be counter productive:

  • The money spend on helemet couldn’t justify the health care saving, and could be better invested somewhere else
  • Helmet campaign promotions paint cycling as a dangerous transportation, discouraging people to cycle, conducting to a less healthy population

One could object that a low absolute bike injuries number is due to a relatively low cycle ridership. The dramatic increase in cycle ridership over the last decade, especially in urban area, is well documented, and still the number of total injuries has not increased but is decreasing [2]:

Bike accident evolution in France

Bike accident evolution in France

The more people bike, the more a bike helmet becomes irrelevant…unless you believe pedestrians should wear an helmet too!


More citation to come

[1] Vélo et casque, Journée spécialisée, jeudi 28 mai 2009, Rapport UMRESTTE 0908, May 2009

[2] Bilan 2011 de la sécurité routière en France

[10] doesn’t express it like it, but I am assuming it is due to a typo.

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