Analysis And Comment

Arguments against helmet legislation are flawed

BMJ 2006; 332 doi: https://doi.org/10.1136/bmj.332.7543.725 (Published 23 March 2006) Cite this as: BMJ 2006;332:725

Health benefits of utility cycling: evidence overlooked

Hagel et al[1] attempt to rebut Dorothy Robinson's evidence[2] that
helmet laws in Australia have had a serious negative effect on public
health, by deterring cycle use whilst failing to improve cyclists’ safety.
In their response, it appears that they do at least accept the evidence
(summarised at [3]) that laws requiring cyclists to wear helmets do indeed
discourage substantial numbers of people from cycling. However they then
go on to argue this does not necessarily indicate damage to public health,
as it is unclear by how much those people reduce their cycle use, or for
how long.

Hagel et al cite a "rule of thumb" (derived from an item of
unpublished personal correspondence) that one needs to cycle for 45
minutes a day, 6 days a week to gain health benefits, and then suggest
that few leisure cyclists are doing this much, implying (presumably) that
the health benefits that we might stand to loose through helmet compulsion
are pretty meagre. Surely though it is not right to refer solely to
“leisure cyclists”, when their own “rule of thumb” suggests that the best
way to gain health benefits is in fact by riding regularly as part of
one’s day-to-day routine – for journeys to work, to school or college, to
the shops? A two-way cycle commute of 20-30 minutes each way is not
unusual, and would easily cover the 1 hour or 40km per week which they
cite as being necessary to reduce CHD risks in 45 to 64 year olds. In any
case, there is other published evidence that cycling for as little as 3km,
3 days a week can still provide benefits[4].

Given that only 35% of men and 24% of women are meeting the national
recommendations for physical activity[5], the threat from helmet-
compulsion is not just that it would reduce existing cycle use, but that
it would seriously undermine efforts to encourage more people to cycle
more often. Cycling, together with walking, is one of the few forms of
physical activity (aside from a few minority activities: jogging, inline
skating etc) which can readily be undertaken in the course of ordinary
daily travel. Unlike gym attendance or most "sporting" activities,
cycling does not require any special outlay of either time or money, and
can readily be fitted into ones normal routines. Once adopted, it is a
habit which is easy to maintain. Moreover, cycle use provides the
greatest benefits in other policy areas besides health – e.g. reduced
congestion, air pollution, road danger and greenhouse emissions – when
undertaken not as a leisure activity but as way of reversing the
inexorable growth of unnecessarily car use, especially for short journeys.

A comprehensive literature review of the health benefits of
cycling[6] provides references to many similar findings, several of them
suggesting that there is a “dose-response” relationship between cycle use
and health gains, but that low levels of cycle use are still beneficial.
A key reference however is a population-wide study from Copenhagen which
found that, compared with people who cycled regularly to work, those who
did not do so had a 39% higher mortality rate, regardless of any other
cycling or other physical activity undertaken by those in each group[7].
This indicates that cycling provides very substantial reductions in all-
cause mortality, which in turn suggests that its health benefits must far
outweigh the risks involved.

That was indeed what the BMA found in its report on Cycling and
Health[8]. Other evidence indicates that those who cycle into middle
adulthood can have a level of fitness equivalent to being 10 years
younger[9] and a life-expectancy 2 years above the average[10]. The
author of the BMA report later estimated that, thanks to these extra life-
years, the health benefits of cycling outweigh the risks by a factor of
around 20:1[11].

When we learn that, two years after helmet laws were introduced,
there was a 43% reduction in cycle use among under 16 year olds in New
South Wales[12] and a 46% reduction among teenagers in Melbourne[13], it
surely does not take a full epidemiological study to realise that those
teenagers growing up after the law are vastly less likely to cycle in
later life than their predecessors (in any case, I dread to think how one
could isolate the effects of a helmet law in a long time-series study of
the type Hagel et al are suggesting, or what it would cost to conduct it).
What is clear is that we need to find ways to support increased cycle use,
both to encourage children to retain the cycling habit through their
teenage years and into adulthood, and indeed for adults to rediscover
cycling, so that exercise becomes part of their daily norm. Cycle
training is a good way to encourage this[14], whereas helmet-compulsion
clearly has exactly the opposite effect.

Hagel et al also fail to note that heart disease due to physical
inactivity kills 42,000 people a year[15], that obesity shortens the lives
of 30,000 people by an average of 9 years per person[16], and that the
costs of physical inactivity and obesity are £8.2bn and £2.5bn
respectively[17]. The numbers killed while cycling are tiny by comparison
– typically around 130 p.a. in recent years[18]. Even then, it is unknown
how many of these could be prevented by helmet-wearing, however helmets
are only designed for impact speeds equivalent to falling from a
stationary riding position[19], whereas around 90% of cyclists’ fatal and
serious injuries involve colissions with motor vehicles[20], making it
very unlikely that helmets could prevent many of the fatal or really
serious injuries which occur, even on the most optimistic assumptions
about their effectiveness. Indeed, we do not know how many of the
cyclists killed are wearing helmets at the time, although media reports
often mention that a helmet was in fact being worn.

In short, helmet laws have the evident potential to shorten hundreds,
if not thousands more lives than they could ever hope to save. Their
effect is not only to reduce existing cycle use but also to deter new
people from becoming regular cycle users. Cycle use for day-to-day travel
is rare – just 1.5% of trips in Britain are cycled[21]. Yet Britain still
has relatively high levels of recreational cycle use – around 9 million
adults (aged over 16) in Britain cycle at least once a year and about half
of them cycle at least once a week[22]. Given concerns not only about
obesity and heart disease, but also congestion, air quality and climate
change, we need to encourage more people to adopt the habit of cycling as
a regular activity, and the large numbers of occasional recreational
cyclists (including children and teenagers) are the obvious “target
group”. We need to achieve rates of cycle use similar to those of
continental neighbours such as Sweden, Germany, Denmark or the Netherlands
(countries which incidentally have much lower helmet-wearing rates, and
better cycle safety – see graph at www.cyclehelmets.org.uk). The vast
majority of Britain’s current adult and child cyclists do not wear
helmets, particularly when riding on minor roads[23]. The last thing we
should be doing is criminalising them any further into car-dependent,
sedentary lifestyles.

Roger Geffen

Campaigns & Policy Manager

CTC, the national cyclists’ organisation

REFERENCES

[1] Hagel B et al. “Arguments against helmet legislation are
flawed.” BMJ vol 332 pp725-726, 2006.

[2] Robinson DL. “No clear evidence from countries that have
enforced the wearing of helmets.” BMJ vol 332 pp 722-5, 2006.

[3] Bicycle Helmet Research Foundation. “How helmet promotion
affects cycle use.” www.cyclehelmets.org/mf.html?1021.

[4] Blair S et al. “Changes in Physical Fitness and All-Cause
Mortality: A prospective study of healthy and unhealthy men.” Journal of
the American Medical Association 1995; vol. 273 pp 1093-98, 1995.

[5] Joint Health Surveys Unit. “Health survey for England 2004 –
updating of trend tables to include 2004 data.” The Stationary Office,
2004.

[6] Cavill N & Davis A. “Cycling and health: a briefing paper
for the Regional Cycling Development Team.” ERCDT, 2003.

[7] Andersen L et al. “All-cause mortality associated with physical
activity during leisure time, work, sports and cycling to work.” Archives
of Internal Medicine vol. 160 pp 1621-8, 2000.

[8] British Medical Association. “Cycling: towards health and
safety.” Oxford University Press, 1992.

[9] Tuxworth W et al. “Health, fitness, physical activity and
morbidity of middle aged male factory workers.” British Journal of
Industrial Medicine vol 43. pp 733-753, 1986.

[10] Paffenbarger R et al. “Physical activity, all-cause mortality
and longevity of college alumni.” New England Journal of Medicine, vol.
314(10) pp 605-613, 1986.

[11] Hillman M. “Cycling and the promotion of health.” PTRC 20th
Summer Annual Meeting, Proceedings of Seminar B, pp 25-36, 1992.

[12] Smith N & Milthorpe F. “An observational survey of law
compliance and helmet wearing by bicyclists in New South Wales.” New South
Wales Roads and Traffic Authority, Sydney, 1993.

[13] Finch F et al. “Bicycle use and helmet wearing rates in
Melbourne, 1987 to 1992: the influence of the helmet wearing law.”
Accident Research Centre report no. 45, pp 35, 36, 43. Monash
University,1993.

[14] Cycle Training UK. “Survey on the effectiveness of cycle
training.” CTUK 2004.

[15] Britton A & McPherson K. “Monitoring the progress of the
2010 target for coronary heart disease mortality: estimated consequences
on CHD incidence and mortality from changing prevalence of risk factors. A
report for the Chief Medical Officer.” National Heart Forum, 2001.

[16] National Audit Office. “Tackling obesity in England.”
Stationary Office, 2001.

[17] Department of Health. “At least five a week: evidence on the
impact of physical activity and its relationship to health.” DoH, London
2004.

[18] National Audit Office. “Tackling obesity in England.”
Stationary Office, 2001.

[19] Glanville H and Harrison N. “Cycle helmets.” British Medical
Association, 1999.

[20] Department for Transport. “Road Casualties Great Britain 2004.”
Table 23. DfT, 2005.

[21] Department for Transport. “Transport statistics Great Britain
2005” Table 1.4. DfT, 2005.

[22] Fox K & Rickards L. “Sport and leisure: Results from the
sport and leisure module of the 2002 General Household Survey.” Office for
National Statistics, 2004.

[23] Inwood C et al. “Cycle helmet wearing in 2004”. Report TRL 644
for the Department for Transport, Transport Research Laboratory, 2005.

Competing interests:
None declared

Competing interests: No competing interests

03 April 2006
Roger N Geffen
Campaigns & Policy Manager
CTC, the national cyclists' organisation (currently GU37 3HS, moving next week to GU2 9JX)
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