Macperson et al. present valuable findings [1] on rates of helmet use
by Toronto children of different income groups; and how these rates varied
across a period in which a helmet law was passed. The wearing rates rise
to a peak after the law of 1995, followed by a decline back to roughly pre-law levels by 1999. This profile occurred because the law was not
enforced. The City of Toronto Police Service c...
Macperson et al. present valuable findings [1] on rates of helmet use
by Toronto children of different income groups; and how these rates varied
across a period in which a helmet law was passed. The wearing rates rise
to a peak after the law of 1995, followed by a decline back to roughly pre-law levels by 1999. This profile occurred because the law was not
enforced. The City of Toronto Police Service confirmed in 2004 that no
child cyclist had been ticketed for not wearing a cycle helmet in that
city[2].
This history raises two issues that warrant further discussion:
1) Risk in cycling:
The principal cause of head injuries to Canadian children is falls,
followed by pedestrian road accidents[3]. There are about six million
Canadians aged 5-19, amongst which an average of 2,200 were admitted to
hospital annually between 1994 and 1998 following a cycling crash[4]. 35%
had head injuries. This is a (serious) head injury rate of 1 per 7,000
capita per year. Is this injury rate great enough to warrant enforced use
of protective headgear? The City of Toronto Police Service, and most of
Ontario society, apparently thought not.
The authors did not discuss reasons for the absence of enforcement.
Their commentary is limited to: “Finally, the role of law enforcement was
not studied; therefore its impact could not be assessed”. Their data make
it clear that enforcement is required to sustain helmet use above what is
found in voluntary jurisdictions. This is a useful piece of knowledge in
the debate on helmet legislation.
A report[5] issued by the Canadian Institute for Health Information
revealed that between 1997/98 and 2001/2, Ontario child cyclist hospital
admissions declined by 12.5%, but head injury admissions specifically
declined by 26%. This advantageous outcome occurred in a period in which,
the authors report, helmet use declined from a peak in 1996/97 to pre-law
levels by 1999. Other evidence[6] reveals that large changes in helmet use
have not noticeably improved serious head injury trends at the population
level.
2)Timely release of data is important:
In a previous paper[7] of 2001, based on the same dataset, Macpherson
et al reported that the introduction of helmet legislation in Ontario had
not deterred children from cycling. The authors reported numbers of
cyclists counted, rather than the extent of enforcement or helmet wearing
rates. However, the conclusion was cited (and still is cited) by
influential bodies in support of the introduction of enforced helmet
legislation. For instance, the British Medical Association reversed its
long opposition to helmet laws and cited the 2001 paper alone in its
change of stance[8]:
“In our 1999 report, significant emphasis was placed on the BMA's
wish not to discourage cycling by making helmets compulsory. The advice
was based on evidence from Australia indicating that cycling levels
decreased following the introduction of legislation. The evidence is now
outdated ... A study from Ontario, Canada has demonstrated that
introduction of helmet legislation did not reduce numbers of children
cycling [referenced to Macpherson et al 2001].
“As with any other legislation, enforcement is as important as the
law itself. Without compliance, the law is at best ineffective...”
The BMA assumed the research referred to an enforced law, when in
fact it referred to an unenforced law, which of course the BMA explicitly
did not wish to see. Such confusion would likely have been avoided had the
2001 paper mentioned that the helmet law was not enforced and helmet
wearing rates returned to pre-law levels by 1999.
References
1.Macpherson A, Macarthur C, To T, Chipman M, Wright J, Parkin P.
Economic disparity in bicycle helmet use by children six years after the
introduction of legislation. Injury Prevention 2006;12:231-35.
2.Personal correspondence with City of Toronto Police Service by A.
Macpherson.
3.Canadian Institute for Public Health data, presented at:
http://secure.cihi.ca/cihiweb/en/media_30aug2006_tab3_e.html
4.Macpherson A, Teresa M, Macarthur C, Chipman M, Wright J, Parkin P.
Impact of mandatory helmet legislation on bicycle-related head injuries in
children; a population-based study. Pediatrics 2002;110:60.
5.“Bicycle-related injuries among Ontario children declining”.
Canadian Institute for Health Information.
http://secure.cihi.ca/cihiweb/dispPage.jsp?cw_page=media_19mar2003_e
6.Robinson DL, No clear evidence from countries that have enforced
the wearing of helmets. BMJ 2006;332:722-25.
7.Macpherson A, Parkin P, To T. Mandatory helmet legislation and
children's exposure to cycling. Injury Prevention 2001;7:228-30.
8.“Legislation for the Compulsory Wearing of Cycle Helmets”. The
British Medical Association 2005.
http://www.bma.org.uk/ap.nsf/Content/cyclehelmetslegis
Hagel and Rowe reject(1) my criticisms(2) of their study of the
impact of a child bicycle helmet law in Alberta, Canada(3). However they
appear to have missed the point.
The first issue raised in my letter concerning reduced cycling as a
result of Alberta's helmet law, Hagel and Rowe say there could have been
confounders which would discount the drawing of a conclusion from the
smaller propo...
Hagel and Rowe reject(1) my criticisms(2) of their study of the
impact of a child bicycle helmet law in Alberta, Canada(3). However they
appear to have missed the point.
The first issue raised in my letter concerning reduced cycling as a
result of Alberta's helmet law, Hagel and Rowe say there could have been
confounders which would discount the drawing of a conclusion from the
smaller proportion of children observed cycling. Actually I did not
suggest the drawing of a conclusion, but rather commented that there was a
red flag deserving of attention considering the reported negative impact
of legislation on cycling that had occurred elsewhere(4). Similar or other
confounders could equally apply to the authors' own conclusion that the
proportion of children wearing helmets increased as a result of Alberta's
law.
Hagel et al also argued that the increased proportion of children
wearing helmets was due to legislation not education or enforcement, yet
they admit there were educational programs in the Alberta area studied and
there was some police enforcement. The authors supported their view by
citing Maryland work(5) which concluded that legislation was more
effective than education. In that case however the legislation was
enforced and therefore is inconsistent with Hagel et al's conclusion.
Other evidence exists which contradicts their conclusion also. A Canadian
survey(6) found educational programs actually do account for increases in
helmet use. I had cited the Ontario evidence which showed helmet use
increases are not sustained by legislation alone anyway in my first
letter.
There were other inconsistencies. Police enforcement in Alberta may
have been more than the authors pointed out. They say 48 tickets were
issued by the Edmonton Police. Were the authors aware that persons under
the age of 16 cannot be charged in Canada? The tickets could only have
been validly issued to a subset of the age group covered in the original
study. It is probable that enforcement among the lower age group took
another form, possibly stern police lecturing. In addition, the Edmonton
Police Service does not and do not have jurisdiction over all of the areas
covered, some of the latter are outside of City boundaries. It must be
assumed that the authors did not contact the RCMP who police the remainder
of the areas to obtain a count of tickets. These two factors suggest Hagel
et al underestimated the degree of police enforcement.
Regarding the second issue concerning their errors in logic, Hagel
and Rowe say that it was their intention to illustrate the degree of
variation in helmet use depending on the helmet and age characteristics of
companions. If that were the case they should have stated so in the
report. Instead they and their colleagues chose to say, "considering that
children riding with helmeted adults are almost 10 times more likely to be
wearing a helmet than children riding with nonhelmeted child companions,
policy makers should consider extending current children-only helmet
legislation in Alberta and other locations." I stated that the relevant
comparison was with non-helmeted adults and showed that children were only
slightly more likely to wear a helmet when with adults. That information
was available from the first Alberta observations yet the authors chose to
use an irrelevant comparison from another jurisdiction, and used it to
reinforce a weak case to extend a helmet law to adults.
References
1. Brent Hagel, Brian Rowe, Emergency Medicine, University of
Alberta (5 September 2006), Re: Alberta helmet article - logic problem and
missing data. Authors reply.
http://ip.bmj.com/cgi/eletters/12/4/262 (accessed 16 December 2006)
2. Avery Burdett (5 September 2006), Alberta helmet article - logic
problem and missing data http://ip.bmj.com/cgi/eletters/12/4/262 (accessed
16 December 2006)
3. Hagel BE, Rizkallah JW, Lamy A, Belton KL, Jhangri GS, Cherry N,
et al. Bicycle helmet prevalence two years after the introduction of
mandatory use legislation for under 18 year olds in Alberta, Canada. Inj
Prev 2006;12(4):262-265
4. Robinson DL. No clear evidence from countries that have enforced
the wearing of helmets. BMJ 2006;332:722-725.
5. Cote´ TR, Sacks JJ, Lambert-Huber DA, et al. Bicycle helmet use
among Maryland Children: effect of legislation and education. Pediatrics
1992;89:1216–20.
6. Parkin PC, Spence LJ, Hu X, Kranz KE, Shortt LG and Wesson DE,
Evaluation of a promotional strategy to increase bicycle helmet use by
children. Pediatrics 1993; Vol 91, 772-777.
Malcom Wardlaw asks if a serious head injury rate of 1 per 7,000
capita per year is great enough to warrant enforced use of protective
headgear. My view is that there is no magic number; even 1 per 70,000
would be too many if the injury had serious sequelae, as undoubtedly many
do. I am certain most sensible parents and most pediatricians who treat
these children would agree. The opinions of the City of Toronto Police
S...
Malcom Wardlaw asks if a serious head injury rate of 1 per 7,000
capita per year is great enough to warrant enforced use of protective
headgear. My view is that there is no magic number; even 1 per 70,000
would be too many if the injury had serious sequelae, as undoubtedly many
do. I am certain most sensible parents and most pediatricians who treat
these children would agree. The opinions of the City of Toronto Police
Service and even that of "most of Ontario society" (which, apparently
Wardlaw has knowledge of) is entirely irrelevant. Police in my city fail
to enforce speeding, red light, and stop sign violations. Why safety is
not their priority remains one of life's great mysteries. It is hardly
surprising then that the authors did not discuss other reasons for lack of
enforcement. If Wardlaw cares to speculate on what he believes these
reasons to be, he should do so.
The decline in head injury admissions noted by Wardlaw only serves to
reinforce the need to enforce helmet legislation, not, as he implies, to
abandon it. The BMA's reversal of its position indicates that it agrees
with this reasoning. Moreover, to suggest that without enforcement laws
are "at best, ineffective..." flies in the face of much evidence to the
contrary. Laws work even when unenforced; they work better when enforced.
It is as simple as that.
How it is possible for Wardlaw to know what the BMA assumed is beyond
my comprehension, as is the confused logic in the sentence in which this
assertion appears. Nonetheless, I continue to struggle to understand why
Wardlaw and others work so consistently to oppose helmet legislation. And,
by the way, I struggle to understand how or why "timely release" figures
into the argument.
My name is Master Sergeant Chairat Noppakovat and I am stationed at
the Madigan Army Medical Center located at Fort Lewis, Washington. I am
in the United States Army and have served proudly for nearly 22 years. The
reason I am writing this letter is to share with you the story of my son.
His name is Apichai Kevin Noppakovat. He was just 18 years old and passed
away on 14 August 2006. He had just g...
My name is Master Sergeant Chairat Noppakovat and I am stationed at
the Madigan Army Medical Center located at Fort Lewis, Washington. I am
in the United States Army and have served proudly for nearly 22 years. The
reason I am writing this letter is to share with you the story of my son.
His name is Apichai Kevin Noppakovat. He was just 18 years old and passed
away on 14 August 2006. He had just graduated from the Clover Park High
School (CPHS) in Lakewood, Washington this past summer. While attending
CPHS, he joined the Air Force Junior ROTC program for four years and
served as a Wing Commander, in the rank of Cadet Lieutenant Colonel.
While at CPHS, he provided tremendous leadership and mentorship to his
fellow ROTC cadets within the program and to all other students inside and
outside of the school. He is the only cadet who has earned the most
ribbons, medals, and other decorations since the AF Junior ROTC has been
in existence at CPHS. Apichai’s dedication and devotion has inspired so
many of his friends, ROTC instructors, school staff, and people in the
community.
My son and his best friend, Nicholas Morales (who was also 18) were
killed on Monday, 14 August 2006 in the University Place located in
Tacoma, Washington. Apichai and his best friend were passengers in the
back seat of his own car. Apichai has a big heart and always allowed his
friends to drive his own car. There were four teens in the car; the
driver, Chris Smith, is 16 and another front seat passenger, John Simpson,
is 17. They were supposed to go bowling that evening until someone drove
past Chris illegally. Chris got upset with that driver and started to
chase him down. It quickly became a road race exceeding the speed of 67
miles in a 35 mile zone. Chris lost control of the vehicle when the other
driver tried to cut him off. The car spun around and the back of the
vehicle struck an oncoming vehicle. It then proceeded to hit a guard rail
and lastly a traffic pole where it finally came to a halt. Apichai and
Nick died instantly; John and Chris survived the crash.
It is a tragic lost for both my family and Ms. Morales (Nick's
mother). The students, ROTC Cadets, school staff, and other friends were
also in so much of pain with these losses. Apichai had made so much
impact for the past four years at Clover Park School District. He led the
team to win the first ever regional unarmed drill team competition. I
cannot describe all of the things that he has done for the school, ROTC
program, and his friends. The Clover Park School District would like to
keep his legacy going so they are planning to create an "Apichai Kevin
Noppakovat" Scholarship at the Clover Park High School. This scholarship
will be dedicated to a senior student at CPHS who has demonstrated the
best leadership, mentorship, and maintained the highest academic
achievement to attend a four year college.
Mitchell, Williamson and Olivier's (2010) study estimated drowning
rates for the Australian state of New South Wales (NSW) in 2005 based on
resident population person-time exposure to swimming. The authors state
(p. 261) that "failure to adjust injury rates for exposure to a hazard
necessarily results in poor estimates of risk", and based on their
findings, conclude (p. 264) drowning mortality rates to be "more than 200...
Mitchell, Williamson and Olivier's (2010) study estimated drowning
rates for the Australian state of New South Wales (NSW) in 2005 based on
resident population person-time exposure to swimming. The authors state
(p. 261) that "failure to adjust injury rates for exposure to a hazard
necessarily results in poor estimates of risk", and based on their
findings, conclude (p. 264) drowning mortality rates to be "more than 200
times higher than equivalent exposure-adjusted rates for road traffic
fatalities." This fact is cited in the Royal Life Saving Society's 2010
National Drowning Report (Royal Life Saving, 2010, p. 3).
However, comparison data detailed below suggest the reported time-
exposure drowning rate presents a gross overestimation of swimming risk.
This is due to deficiencies in reported numerator data and denominator
estimates.
The majority of unintentional drowning death cases included in the
reported numerator would be unlikely to come from the population
denominator (swimmers). This is a key principle for calculating population
rates (Robertson, 2007). Australia-wide unintentional drowning deaths
reported for July 2004 to June 2005 identified 97 (37.5%) of 259 victims
engaged in a swimming / leisure activity (Royal Life Saving, 2005). In the
following 12 month period (2005-2006) this figure was 54 (20.4%) of 265
unintentional drownings (Royal Life Saving, 2006). NSW drowning mortality
data, as a subset of national data, would be expected to follow a similar
pattern. Mitchell et al. (2010) did not report the numerator frequency for
drowning deaths.
Mitchell et al. (2010) report a rate of 90,000 drowning deaths per 10
million hours of swimming in NSW for 2005 (p. 264). The rate indicates
that for every thousand hours of swimming at a NSW public pool, river,
beach or other location, nine swimmers will drown. But Sydney's Bondi
beach alone caters to thousands of bathers most days during summer--yet
drowning remains a relatively rare, and not daily, event. Drowning
protection at this beach, given the risk of swimming indicated by the
reported rate, may be explained by regular surf lifesaver patrols. Even
so, the NSW population, which numbers many millions concentrated in
coastal areas experiencing a mild to warm climate, will likely spend
numerous hours swimming in unpatrolled locations.
The reported rate of 90,000 drowning deaths per 10 million hours of
swimming must be questioned given that the annual frequency of drowning
among swimmers in NSW is probably well below one-hundred. Fortunately, a
check of this rate is readily available using swimming participation data
reported by the Australian Bureau of Statistics (2007) for 2005-2006.
These data were collected using a method and time period consistent with
exposure data relied upon by Mitchell et al. (2010).
In the previous 12 months for Australia (2005-2006), 1,447,300
persons aged 15 and over residing in private dwellings (9% of the national
population) were estimated to have participated in organised (13%) or
unorganised (87%) swimming. (The swimming participation rate for NSW was
estimated by the Australian Bureau of Statistics (ABS) to be marginally
higher at 10 percent of the population or 556,400 persons.) For national
swimmer estimates in the 12 months prior to sample interview, 1.1 million
(76%) reported swimming 53 times or more, 186,300 (13%) 27 to 52 times,
89,500 (6%) 13 to 26 times, and 71,500 (5%) 12 or less times. This
estimate equates to a minimum of 64,565,100 swimming episodes in Australia
by residents for the 12 month period.
Based on minimum participation frequencies reported by the ABS, I
have estimated person-time exposure and drowning rates (using a numerator
of 80 drowning deaths while swimming--the average over a five year period
to 2006 [Royal Life Saving, 2006]) for mean bathing-time exposures per
swimming episode of 30 minutes. The calculation was based on conservative
estimates (lowest swimming frequency by frequency group) and ignores what
is likely to be millions of bathing hours undertaken by international
visitors to Australia (note that drownings of international tourists were
included in numerator data). This produced a rate of 24.8 drownings per 10
million hours of swimming. (Note: Mean swimming episodes at 15 minutes
yielded a rate of 49.6 and at 60 minutes 12.4, per 10 million hours of
swimming.)
Substantial differences between the person time-exposure rate
reported by Mitchell et al. (2010) and that listed above (respectively,
90,000 drowning deaths in NSW compared with 25 drowning deaths in
Australia, per 10 million hours of swimming) are unlikely to be explained
by differences in water exposure or drowning patterns between NSW and
other Australian states and territories. Perhaps Mitchell et al. applied
sample exposure data in the denominator without extrapolation to the
population?
In comparison with reported traffic mortality time-exposure rates,
the time-exposure rate of drowning mortality for persons exposed to
swimming in Australia appears higher. But rather than being 200 times
higher as reported in the study, it's more likely to be a factor below 10.
Mitchell et al. (2010) rightly state (p. 264) that "In terms of
policy development, under- or overestimation of the true risk of injury
can lead to poor identification of priorities for developing injury
prevention policies and interventions, and inadequate resource
allocation." The reported rates emphasize the need for precision so as not
to perpetuate these challenges to injury problems including drowning.
A spreadsheet with supporting data is available on request.
References cited:
Australian Bureau of Statistics (2007). Participation in Sports and
Physical Recreation, 2005-06 (cat. no. 4177.0). Canberra: ABS.
Mitchell, R. J., Williamson, A. M., & Olivier, J. (2010).
Estimates of drowning morbidity and mortality adjusted for exposure to
risk. Injury Prevention, 16(4), 261-266.
Robertson, L. S. (2007). Injury Epidemiology: Research and Control
Strategies (3rd ed.). New York: Oxford University Press.
Royal Life Saving (2005). The National Drowning Report 2005. Sydney:
Royal Life Saving Society.
Royal Life Saving (2006). The National Drowning Report 2006. Sydney:
Royal Life Saving Society.
Royal Life Saving (2010). The National Drowning Reports 2010. Sydney:
Royal Life Saving Society.
In his zeal to defend bicycle helmet laws, Editor Barry Pless ignored
two important issues identified by Malcom Wardlaw and in doing so raises
one of even more vital importance.
First, child cyclist head injuries declined in Ontario while data
from Macpherson showed a declining rate of bicycle helmet use. This
suggests a factor other than helmet use and helmet laws was responsible
for the decline
in head injurie...
In his zeal to defend bicycle helmet laws, Editor Barry Pless ignored
two important issues identified by Malcom Wardlaw and in doing so raises
one of even more vital importance.
First, child cyclist head injuries declined in Ontario while data
from Macpherson showed a declining rate of bicycle helmet use. This
suggests a factor other than helmet use and helmet laws was responsible
for the decline
in head injuries. Second, the authors of the 2001 Injury Prevention study
which concluded that Ontario's helmet law had not negatively impacted
levels of cycling, however they were aware but failed to mention two
critical factors in evaluating the effect of helmet laws - (a) within four
years the law had reached a null impact on helmet use, and (b) the lack of
police enforcement.
In an editorial, Pless has admitted his own biases and sensitivities
in dealing with issues concerning bicycle helmets[1] and Macpherson
recently appeared in the Ontario Legislature[2] in support of a motion to
impose a helmet law on adults. Such activism raises questions about
whether personal biases are taking priority ahead of scientific findings
and criticisms.
Pless says that he struggles to understand why Wardlaw and others
work so consistently to oppose helmet legislation. This is an astonishing
statement given Wardlaw along with Robinson, myself and others restrict
ourselves to questioning the science upon which helmet laws are based. If
Pless doesn't understand the fundamental objection to having the state
unjustifiably impose a requirement on its citizens, then what he's really
saying is that he struggles to understand human nature.
Please, let's restrict ourselves to facts. Political activism doesn't
belong in a scientific journal.
References
1. Pless B, Are Editors free from bias? The special case of Letters
to the Editor, Inj Prev 2006 12: 353-354. doi:10.1136/ip.2006.014472
2. Hansard, Legislative Assembly of Ontario, 14 December 2006
I welcome the paper by Chotani et al on violence in Pakistan and the empirical nature of the exploration.[1] It is also encouraging to see Injury Prevention raise the issue of violence in developing countries, as it is a neglected health problem. However, from the Pakistani context, there are several contextual and explanatory points that are needed to clarify some of the issues raised in the paper...
I welcome the paper by Chotani et al on violence in Pakistan and the empirical nature of the exploration.[1] It is also encouraging to see Injury Prevention raise the issue of violence in developing countries, as it is a neglected health problem. However, from the Pakistani context, there are several contextual and explanatory points that are needed to clarify some of the issues raised in the paper and also to add to them.
Macro-economic changes have affected the Pakistani society for the past two decades with important impacts on the health and social sectors.[2] One of the impacts is on the levels of violence and unintentional injuries - trends that have not been appropriately studied in the developing world. The imapact of adjustment programs like the Social Action Program in Pakistan therefore merit discussion in a dialogue exploring the nature and patterns of violence.
I disagree with the claim made in the paper that there have been no comparisons of police data with other data sources in Pakistan. National burden of disease analysis for Pakistan included all types of injuries and used such a comparative analysis.[3] Moreover, innovative sources of data have also been compared to police data on violence, in the literature.[4] Indeed more work needs to be done in this area to enhance the internal consistency of data from Pakistan - a research agenda for the country.
I was surprised to note the lack of attention to the role of firearms in the discussion and prevention part of the paper. The influx of firearms since the eighties, the relationship with substance abuse, and the drug trade are important considerations for exploring violence in Pakistan. There are major economic relationships between these factors and all of them facilitate and potentiate the occurence and impact of violence in the country, including political and ethnic violence. Most importantly, the control of firearms and their use is a potential preventive strategy which needs to be explored in the Pakistani context.
Although not the intent of the study, it is worth reflecting that there are enormous costs to violence everywhere. In addition to the direct and indirect medical and treatment costs to those injured or dead, there are societal costs in the form of preventive, rehabilitative, structural, and quality of life factors. If such an assessment was to be done in Karachi, I am sure one could attribute a large cost amount to violence. We must begin to use economic arguments as well, to enhance the case for greater attention to violence in the developing world.
As suggested by the authors, it is time to analyze the causes and consequences of violence in Pakistan systematically. The use of evidence in doing such analysis is critical; the development of a framework to link the different causative and impact pathways is vital; and finally the ability to mobilize Pakistani society to reject such violence and develop their own capacity for preventing it, is probably the most important.
References
(1) Chotani HA, Razzak JA, Luby SP. Patterns of violence in Karachi, Pakistan. Injury Prevention 2002;8:57-59
(2) Bhutta Z. Structural adjustment and the impact on health and society: perpsective from Pakistan. Int J Epidemiol 2001;30:712-16
(3) Hyder AA, Morrow RH. Applying burden of disease methods in developing countries: a case study from Pakistan. Am J Public Health 2000;90:1235-40
(4) Ghaffar A, Hyder AA, Bishai D. Newspaper reports as a source for injury data in developing countries. Health Policy Planning 2001;16(3):322-325
The Editor of IP does not like the fact that a debate exists about
cycle
helmets. (1) He would like not to publish correspondence from helmet
sceptics. He describes the letters he has received as frustrating and
irritating
“repeated almost boilerplate arguments”. It is welcome and honest of the
Editor to state his willingness to publish helmet sceptic eletters despite
his
dislike for this view. It compares with the a...
The Editor of IP does not like the fact that a debate exists about
cycle
helmets. (1) He would like not to publish correspondence from helmet
sceptics. He describes the letters he has received as frustrating and
irritating
“repeated almost boilerplate arguments”. It is welcome and honest of the
Editor to state his willingness to publish helmet sceptic eletters despite
his
dislike for this view. It compares with the actions of a recent editor of
the
British Medical Journal, the flagship journal of IP’s parent company. When
criticized for publishing controversial eletters about passive smoking
Smith
spoke of the journal’s deep commitment to unfettered debate (2). He went
on to quote Milton, “Truth was never put to the worse in a free and open
encounter”.
The eletters section of IP is a great place for the cycle helmet
debate to unfold
and might attract more interest to the eletters page. A look at this page
today shows only 5 postings on 3 topics over the last 90 days, one of
which is
from the editor. In contrast the paper by Robinson (3) and critique by
Hagel
and Pless (4) in the BMJ has generated 45 rapid responses of varying
points of
view, from people all over the world. The sad thing for IP is that the
editor
does not want a debate on helmets, in part I think because he is convinced
of
the infallibility of his own personal beliefs on the issue. The debate
will just
take place elsewhere instead.
A debate exists because interpretations of the scientific evidence
differ.
Partly this is due to philosophical differences, what Adams calls
‘cultural
filters’. These make more difference when ‘the state of the evidence is
contested, ambiguous or inconclusive, a description that covers most
controversies about safety.’ (5)
Contested, ambiguous and inconclusive pretty much describes the state
of
the cycle helmet literature. We have several case control studies
comparing
head injuries in cyclists who crashed with and without helmets (6). These
are
beloved of helmet enthusiasts because they generally conclude helmets are
very effective at reducing head injuries in the event of a crash. They
are
quoted by charities and authorities that want to encourage helmet wearing
and those who want us to pass laws forbidding cycling without helmets.
Sceptics point out there is no ‘real world’ evidence that helmets actually
work
when a population of cyclists starts to wear them. The four most recent
ecological studies looking at this examined both head injuries and
fatalities in
cyclists (7-10). None of these studies provides evidence that helmets
make a
difference.
Pless says that ecological studies are weaker than case control
studies. The
Centre for Evidence Based Medicine in Oxford disagrees. It places
ecological
studies above systematic reviews of case control studies. In a table,
ranking
hierarchies of evidence ecological studies are 2c and reviews of case
control
studies with homogeneity 3a (11). The conflict between what case control
studies predict should happen and what has actually happened needs
explaining. As Pless states “The moral here is that solid research
designs
cannot be discounted just because you don’t like the answers they give.”
Indeed. The results of the ecological studies need debating and
explaining
not dismissing. The challenge for helmet enthusiasts is to explain why
helmet wearing has not resulted in lower head injury rates.
Whether this debate is allowed to unfold on IP or in other fora, I
hope it will
be conducted using temperate language in an atmosphere of mutual respect.
References
1. Pless, B. Inj Prev 2006;12:353-354
2. Smith , R. BMJ 2003;327:505
3. Robinson, R. BMJ 2006;332:722-725
4. Hagel, B Pless, B. BMJ 2006;332:725-726
5. Adams, J Risk Routledge 1995: p 81.
6. Helmets for preventing head and facial injuries in bicyclists, The
Cochrane Library, Issue 4, 2006. Thompson DC, Rivara FP, Thompson R.
7. Cycle helmets and road casualties in the UK ?
Hewson PJ. Traffic Injury Prevention, 2005;6(2):127-134.
8. Investigating population level trends in head injuries amongst
child
cyclists in the UK ?
Hewson PJ. Accident Analysis & Prevention. 2005;37(5):807-815.
9. Do enforced bicycle helmet laws improve public health? ?
Robinson DL. . BMJ, 2006;332:722.
10. Trends in helmet use and head injuries in San Diego County: the
effects
of bicycle helmet legislation, Ji M, Gilchick R, Bender S. AA&P (38) 2006,
128-134.
I would suggest that if there is a risk compensation affect with
respect to bicycle helmets it would be very short lived. As any cyclist
knows even with a helmet it still hurts like hell when you fall off!
There is a plausible case that television affects the individual road-user's attitudes to safety-related issues, so McGwin et al [1] provide a
useful survey of television content regarding the portrayal of seatbelt
and helmet use. Whether McGwin et al should make such strong assertions
about the value of these devices raises arguments which have been aired
elsewhere [2].
There is a plausible case that television affects the individual road-user's attitudes to safety-related issues, so McGwin et al [1] provide a
useful survey of television content regarding the portrayal of seatbelt
and helmet use. Whether McGwin et al should make such strong assertions
about the value of these devices raises arguments which have been aired
elsewhere [2].
Such surveys could be extended to other issues. Speed could be an
excellent example, but is difficult to assess with any accuracy from TV
material. Another issue is driver distraction, which may be more amenable
to observation. Driver distraction is depicted commonly in filmed fiction:
an example at random is Stephen Daldry's movie "The Hours", in which a
driver and her passenger partake in intense dialogue, leading to steadily
more erratic and dangerous driving.
However, the issue of distraction extends beyond the requirements of
a film's plotline: monologues and interviews while driving have become
quite a common custom in factual broadcasting. A recent BBC example
concerned historical battle sites. The presenter was filmed making an in-depth commentary while driving through locations associated with the
battle. The camera provided a side view of the presenter within the
vehicle, but views of the locations were meagre. Worryingly, but not
surprizingly, the presenter's gaze frequently shifted from the road to the
camera. One must conclude that the commentary would have been just as
effective if it had been recorded in a studio - and safety would not have
been compromised.
The issue of how far TV should convey accepted safety norms raises a
number of issues; three examples: (a) Should depiction of safe behaviour
necessarily override the plotline requirements of a piece of fiction?
(b) Would the fantastical road scenarios portrayed in the likes of James
Bond movies and Homer Simpson cartoons really influence viewers' attitudes
to safety? (c) Can the above-cited scene from "The Hours" in fact act as a
warning leading to better driving behaviour?
What can surely be accepted is that gratuitous broadcasting customs
can be curtailed with no loss to anyone; if there is a small gain in
safety-relative attitudes, then that is all to the good.
References
1. McGwin G, Modjarrad K, Reiland A, Tanner S, Rue LW. Prevalence of
transportation safety measures portrayed in primetime US television
programs and commercials. Inj Prev 2006;12:400-3.
2.Reinhardt-Rutland A H. Seat-belts and behavioural adaptation: the
loss of looming as a negative reinforcer. Safety Sci 2001;39:145-55.
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I would suggest that if there is a risk compensation affect with respect to bicycle helmets it would be very short lived. As any cyclist knows even with a helmet it still hurts like hell when you fall off!
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There is a plausible case that television affects the individual road-user's attitudes to safety-related issues, so McGwin et al [1] provide a useful survey of television content regarding the portrayal of seatbelt and helmet use. Whether McGwin et al should make such strong assertions about the value of these devices raises arguments which have been aired elsewhere [2].
Such surveys could be...
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