Mar 24 '06 - 1151 W - Vote Good + 9 :: Bad - 9 Helmet Battle Flares Up in British Medical Journal
Published March 24, 2006 by BikeBiz
Australian statistician Dorothy Robinson has a cycle helmet
anti-compulsion paper published in this week's British Medical Journal.
Another paper, from four professors of epidemiology from Canada and the
US, counters her arguments.
Legislating to make bicycle helmets compulsory for all cyclists
reduces bicycle usage and is bad for full-population health, argues
Robinson.
This is a long held position, well known to helmet
anti-compulsionists, but now given three and a half pages in the
influential BMJ.
In June 2005, the doctor delegates at the British
Medical Association's annual representative meeting voted yes to a
motion calling for compulsory helmet wearing for cyclists.
At the close of the five-minute debate on the motion,
Sam Everington, deputy chair of the BMA's council said: "We've had an
enormous amount of letters about serious injuries caused by not using
helmets."
He did not mention the March 2005 letter sent to the
BMA by 45 doctors and PhDs, urging the BMA to reconsider its helmet
compulsion position, now official BMA policy.
The list of docs on the letter included many experts,
including a senior lecturer in paediatric pathology, a professor of
medical statistics, a professor of medicine and metabolism, a
consultant psychiatrist, a consultant in emergency medicine, and a
consultant in public health.
The non-medical docs included a Fellow in system safety engineering, a PhD in risk assessment and a materials engineer.
And statisticians like Dorothy Robinson also worry about the
"contradiction between predicted benefits from case-control studies but
minimal changes in head injury rates when helmet wearing increased
substantially because of legislation."
Robinson - a helmet-wearing cyclist - comes from the
land of the helmet law and is senior statistician at the University of
New England, New South Wales, Australia. She is an expert in
statistical modelling, "especially how biased and misleading results
can be obtained from fitting incorrect or inappropriate models."
Using crash stats from Australia and New Zeland she
said there is no clear evidence that bicycle helmet laws improve public
health.
She reviewed data before and after helmet legislation
and believes helmet laws discourage cycling and produce no obvious
response in the number of head injuries.
She said: "This contradiction may be due to risk
compensation, incorrect helmet wearing, reduced safety in numbers
(injury rates per cyclist are lower when more people cycle), or bias in
case control studies."
She suggested that helmet laws are counterproductive
and that governments should instead focus on measures that lead to huge
drops in mortality figures, such as campaigns to deter motorists who
speed, drink, and fail to obey road rules.
"Helmet laws would be counter productive if they discouraged cycling and increased car use," said Robinson.
"Wearing helmets may also encourage cyclists to take more risks, or motorists to take less care when they encounter cyclists."
Research from the UK's Transport Research Laboratory backs this up:
motorists drive closer to cyclists who wear helmets, believing these
cyclists to be more proficient and "protected" with safety equipment.
The medical academics from the US and Canada who argue
against Robinson - including Frederick Rivara, author of a helmet paper
which released the "85 percent of deaths would be prevented by wearing
helmets" stat to the world, a deeply flawed stat, say anti-compulsion
campaigners - argue that helmet compulsion is sound.
Assistant professor Brent Hagel of Montreal Children's
Hospital Research Institute, and colleagues, said in a one and a half
page piece: "Robinson's opposition to helmet laws is contrary to
published evidence on the effectiveness of bicycle helmets. At least
six independent studies have reported a protective association between
wearing bicycle helmets and head injuries."
The authors appear to agree that helmet compulsion leads to a drop in cycle usage.
Their paper said "let's assume legislation does discourage a large
proportion of cyclists. The crucial question is whether the decision
not to ride, for however long, truly diminishes physical fitness. In
other words is the trade-off between head protection and physical
fitness worth it?"
So, from their point-of-view, it would be OK for
helmet compulsion to lead to less cyclists because the ones that were
left would be "safer." This is a position that ought to worry the bike
trade. Any measure that leads to less cycling would be bad for the bike
trade.
The British Medical Association famously said that the risks of cycling are far outweighed by the health benefits of cycling.
Link to Robinson's Report:
http://bmj.bmjjournals.com/cgi/content/full/332/7543/722-a/DC1
Related article:
Experts Collide over Benefits of Cycle Helmets
Published March 25, 2006 by Sydney Morning Herald
By Ben Cubby
FORCING cyclists to wear helmets damages public health because they discourage many people from riding, an academic says.
Dorothy Robinson, a former senior statistician at the University of New England, found that while laws that make wearing helmets mandatory reduced the seriousness of some head injuries, the cost to public health and fitness outweighed their benefit.
But some researchers suggest Ms Robinson's conclusions "crumble" under scrutiny.
Writing in the British medical journal BMJ, Ms Robinson compares data between countries and regions that have made it illegal to ride without head protection.
"When we brought in helmet laws it discouraged people from cycling; there was a big drop," says Ms Robinson, a keen cyclist who has been struck by a car and wears a helmet.
"The overall effect on public health is bad, with less people getting fit by cycling since the laws came in, and more driving."
One study she used found the number of bicycle riders counted at 25 locations around Sydney fell by 48 per cent between 1991, when mandatory helmet laws were introduced in NSW, and 1996.
In surveys riders frequently said helmets were uncomfortable and expensive, she says.
Mandatory helmet laws were still "very contentious", said Peter Strang, executive director of the Bicycle Federation of Australia. It opposed the laws when they were introduced, but many of its constituent associations have since accepted them.
"[Ms Robinson] certainly makes some claims that I think deserve further research," he said.
A group of researchers - Brent Hagel, Alison Macpherson, Frederick Rivara and Barry Pless - also writing in BMJ, dismisses Ms Robinson's conclusions.
"For example, a fall in the number of bicyclists in the 1990s may simply reflect an increase in in-line skating or other recreational activities," they say.
They also say that there is no proven link between a decrease in cycling and falling fitness levels.
The Roads and Traffic Authority did not respond directly to Herald queries about mandatory helmet use. A correctly worn helmet "can reduce the risk of head and brain injury by up to 85 per cent in a crash", the authority said.
The NSW Minister for Sport and Recreation, Sandra Nori, was sceptical. "I haven't seen the research yet, but it doesn't appear to address the grave problem of head injuries caused by bike accidents."
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