Please note: In 2003, the CTF updated its Grades of Recommendations to include an "I Recommendation" for situations where insufficient evidence exists to allow a recommendation to be made. (Formerly, these situations were captured under a "C Recommendation".) This change is not retroactive, and all "C Recommendations" made prior to 2003 have not been reevaluated in light of the new "I" recommendation grade. For a discussion of these recommendation grades, please link to the 2003 article in the Canadian Medical Association Journal here.
Overview
In 1979,
the Canadian Task Force on the Periodic Health Examination recommended
that physicians attempt to control underlying medical conditions, counsel
the disabled, and encourage the use of seat belts by all drivers and passengers
(C Recommendation). In 1989,
the U.S. Preventive Services Task Force recommended that all individuals
be urged to use occupant restraints (safety belts and child safety seats)
for themselves and others, to wear safety helmets when riding motorcycles,
and to refrain from driving while under the influence of alcohol or other
drugs.< 1
The Canadian Task Force concurs with these recommendations.
Burden of
Suffering
Of the ten industrialized
western countries Canada has the fourth highest injury mortality rate (37.5/100,000)
and the sixth highest motor vehicle accident (MVA) fatality rate (15.8/100,000).
In 1987,
the crude fatality rate for males was 18.4/100,000
and 9.6/100,000
for females. Figure 1displays
the fatal injury rate from MVA according to the various age groups. Although
the gender curves are of similar shape, the rate for males is consistently
almost twice that of females. The risk of motor vehicle crashes is also
increased for persons over age 60, but elderly motorists account for only
10%
of fatal crashes, primarily because they drive less distance than younger
persons.<2 Fatalities are but the tip of the iceberg; Figure
2 displays the nonfatal injury rate for the various age groups.
The gender curves closely approximate each other except for the young adult
group (19-34
yr). Motor vehicle injuries occur most commonly in males and in persons
aged 15-24.
This age group has the highest mortality rate and accounts for one-third
of all deaths from motor vehicle crashes. Motor vehicle crashes are the
leading cause of death in persons aged 5-24; in 1986
they accounted for 38% of all deaths in young persons aged 15-24.<3
High Risk Behaviours
The relationship between seatbelt
use and the severity of injury is displayed in Figure
3. The rate of seat belt use among those persons fatally injured
was considerably less than among those with nonfatal or no injuries from
MVAs. The pattern of seatbelt use in Canada closely parallels the introduction
of seatbelt legislation in the various provinces. For example, the rate
in Alberta rose from 28% in 1986
to 83% in 1988
after the introduction of mandatory seatbelt legislation in July 1987
(Figure 4). About 40% of persons
killed in motor vehicle crashes are intoxicated by alcohol.<4 Studies
have consistently shown that fatally injured drivers are more likely to
have a blood alcohol level of at least 0.10%
than are drivers who are not killed. In addition to its role as a risk
factor for causing motor vehicle crashes, alcohol intoxication increases
the risk of death or serious injury during and after a crash, and can limit
the ability of the victim to escape from the vehicle. Alcohol-intoxicated
survivors with severe brain injuries appear to have longer hospitalizations
and more persistent neurologic impairment than those who were not intoxicated.
(For more information on problem drinking consult Chapter 42).
Medical Impairment
Impaired vision, impaired
hearing, decreased flexibility and dexterity, and slowing of information
processing capability result in abnormally high accident rates in the elderly
when exposure is taken into account.<5 Less than 0.5% of all deaths
of elderly people are the result of road accidents, but elderly drivers
are over represented in low velocity, property-damage-only collisions.
Whether drivers with concomitant medical conditions have excessive motor
vehicle accidents is less clear. Most studies show that there is an excess
of crashes among drivers whose medical condition is known to Departments
of Motor Vehicles compared to drivers not reported to have medical problems.<6
An examination of the driving performance of drivers with selected medical
impairments has resulted in the requirement for medically impaired drivers
to obtain medical report forms from their physicians, and the development
of tables of assigned weights for comorbid conditions. These tables are
used by insurance companies and motor vehicle branches to designate different
levels of restriction. Practitioners must comply with the obligation to
report to the regional Department of Motor Vehicles patients who do not
meet the criteria for maintaining a driver’s license.
Off Road Vehicles
Most injuries associated with
all-terrain vehicles (ATVs) occur when the driver loses control, the vehicle
falls over, the driver is thrown from the vehicle, or the vehicle collides
with fixed objects such as fences or trees. The 1987
data for numbers of vehicles in use and mortality, without reference to
patterns of vehicle use, yielded annual death rates of 1.7/1000
for 3-wheeled and 1.2/1000
for 4-wheeled ATVs.<7 A review of data in 1986
identified 23 deaths and 572 hospitalizations in Quebec. Males accounted
for 85% of hospitalizations. Canadian and U.S. studies have revealed the
following risk factors: excessive speed, improper apparel and nonuse of
helmets, inexperience, and alcohol abuse.<8
Effectiveness
of Prevention Maneuvers
The effectiveness of occupant
protection systems has been demonstrated in a variety of study designs
that include laboratory experiments (using human volunteers, cadavers,
and anthropomorphic crash dummies), postcrash comparisons of injuries sustained
by restrained and unrestrained occupants, and postcrash judgements by crash
analysts regarding the probable effects of restraints had they been used.<9
Based on such evidence it has been estimated that proper use of lap and
shoulder belts can decrease the risk of moderate to serious injury to front
seat occupants by 45-55% and can reduce crash mortality by 40-50%. When
brought to the hospital, crash victims who were wearing safety belts at
the time of the crash had less severe injuries, were less likely to require
admission, and had lower hospital charges.<10
Airbags are in effect 100%
of the time, whereas it is estimated that currently the 3-point seat belt
is not worn by 25% of Canadians. Seat belts and airbags are not alternatives
– they complement each other. The primary advantage of airbags is that
they require no active participation by the occupants of the vehicle. High
risk groups, in light-trucks and in rural areas are particularly vulnerable
because of their lower rate of seat belt usage. The overall safety benefit
of the combination of lap-shoulder belt and airbag system use has not yet
been determined from field accident data, however, estimates based on the
analysis of fatal crashes involving belted front seated occupants, a potential
additional fatality prevention of 3-5% when a combination lap-shoulder
belt and airbag system is used.<11
Child safety seats also appear to be effective. It has been reported that
unrestrained children are over 10
times as likely to die in a motor vehicle crash than are restrained children,<12
although these data come from studies with important design limitations.
Other studies suggest that child safety seats can reduce serious injury
by 67% and mortality by 71%.
Child restraints may also reduce noncrash injuries to child passengers
by preventing falls both within and out of the vehicle. By wearing safety
helmets, persons who operate or ride on motorcycles or ATVs can reduce
their risk of injury or death from head trauma in the event of a crash.
In regions where their use is required by law, such helmets have been shown
to reduce mortality by about 30%. Head injury rates are reduced by about
75% among motorcyclists who wear safety helmets.<13
Regions that have repealed mandatory motorcycle helmet laws have experienced
significant increases in motorcycle fatalities.
Effectiveness
of Counselling
There is a paucity of information
from clinical studies on the ability of physicians to influence patients
to refrain from driving while intoxicated. Similarly, there have been few
studies examining the effectiveness of physician counselling to use safety
belts.<14
The strongest evidence that clinician counselling can be effective comes
from programs that have encouraged parents to use infant safety seats before
the practice became widely mandated by law. Results from such programs
suggest that significant short-term improvements are possible immediately
after newborns are discharged, but the effect is rarely maintained for
more than a few months.<15
A controlled trial without randomization found that the combined intervention
of pediatrician counselling, a prescription for an infant restraint, and
a pamphlet on crash protection was associated with increased correct use
of infant safety seats as assessed at the first two monthly well-baby visits.
A small randomized study demonstrated that a "loaner seat" and instruction
provided by a nurse resulted in increased use after two to four weeks.
The same researchers in a subsequent trial found that a comprehensive hospital
program combined with recent state legislation was effective in improving
correct usage, but intensive counselling from pediatricians and nurses
was of no additional benefit. Another controlled study found that personal
discussion was of limited value; a subgroup receiving free infant restraints
and literature demonstrated slightly higher correct usage at discharge,
but there was no significant difference between the groups in two to four
months. Finally, another study found that pediatrician counselling resulted
in an immediate increase in safety belt use, but there was no difference
in usage rates between the study group and controls at one-year follow-up.<16>
Recommendations
of Others
The use of safety belts and
child safety seats is widely recommended by organizations and agencies
concerned with injury prevention. Child safety seats are required by law
in all 50 states and all 10
Canadian provinces. Mandatory safety belt laws are in effect in most states
and all the provinces of Canada. Recommendations specifically urging physicians
to counsel patients to use occupant restraints have been issued by a number
of organizations, including the Canadian Medical Association, the College
of Family Physicians, and the National Highway Traffic Safety Administration.
The Canadian Medical Association has made recommendations on a wide range
of vehicle safety standards – restraint systems, running lights, motorcycle
helmets, mopeds, all-terrain vehicles, minivans and light trucks; and supports
legislation aimed at decreasing the incidence of drinking and driving.
General Council resolutions have also been made regarding airbags and elimination
of seat belt use exemptions for police officers and taxi drivers. The American
Academy of Pediatrics also recommends counselling adolescents to abstain
from intoxicants when driving; advising parents and children to discuss
the proper use of alcohol at teen parties; and suggesting alternatives
to driving while intoxicated or riding in a vehicle operated by an intoxicated
driver.<17>
Conclusions
and Recommendations
There is good (grade I) evidence
that persons who use occupant protection<9,10
and avoid driving while intoxicated<4,18
are at significantly decreased risk of injury or death from motor vehicle
accidents. There is fair (grade II-2) evidence that wearing safety helmets
when operating/riding motorcycles or all-terrain vehicles reduces the risk
of accidental injury or death.<7,8 Expert opinion (grade III) suggests
that many patients seen by clinicians could benefit from counselling to
modify their behaviours as drivers and passengers in motorized vehicles.<15
Since motor vehicle crashes represent a leading cause of death and nonfatal
injury, even modest successes through clinical interventions could have
major public health value. In actual practice, however, it is not known
how effectively clinicians can alter these behaviours. Counselling is most
relevant for those at increased risk of motor vehicle injury, such as adolescents
and young adults, persons who use alcohol or other drugs, and patients
with medical conditions that may impair motor vehicle safety.<5 The
optimal frequency for counselling patients about motor vehicle injury has
not been determined and is left to clinical discretion.
Unanswered
Questions (Research Agenda)
Ideally, the effectiveness
of physician counselling concerning a number of efficacious practices related
to the prevention of motor vehicle accident injuries should be evaluated.
However, because many of the preventive maneuvers have become widely mandated
by law, the evidence that clinician counselling can influence patient behaviour
concerning these practices is unlikely to be defined.
Evidence
The Medline search strategy
for this review identified articles for the years 1981-1991
using
the following MESH headings:
This review was initiated in June 1991 and recommendations were finalized in November 1992. A technical report with a full reference list dated February, 1993 is available upon request.
Full Citation
Elford RW. Prevention of motor vehicle accident
injuries. In: Canadian Task Force on the Periodic Health Examination. Canadian
Guide to Clinical Preventive Health Care. Ottawa: Health Canada,
1994; 514-24.