|
Items in cart [0] |
Questions? Call 888-624-8373 |
| ||||||||||||
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 25
2
Epidemiology of Injuries:
The Need for More Adequate Data
Epidemiology is the fundamental science for studying
the occurrence, causes, and prevention of disease.
Injury epidemiology is a young scientific field with a
theoretical basis within the wider framework of
epidemiology ? 2 7 6 7 7 ~ 6 3 This new discipline has
focused on the development of epidemiologic tools to
identify problems, def ine their extent, and determine
causative factors that are amenable to intervention. An
equally important objective has been to develop evaluation
methods to determine the effectiveness of counter
meaSUreS. 2 7 7 ~ 2 0 7
Epidemiologic studies of injury should not exist in
isolation, but must be able to draw ideas and methods
from clinical, laboratory, and biomechanical research,
just as these other forms of research need to draw from
epidemiology. Furthermore, research methods applied to
one segment of injury analysis may be relevant to others.
For example, methods used for air-crash investigation
have been applied to analysis of train crashes. Such
exchange of ideas and methods is common in disease
research, but unfortunately not in injury research.
A prerequisite for the scientific study of injury is
the acquisition of data on which to base priorities and
research. Despite the obvious importance of injury as a
public health problem, information to permit the study of
the epidemiology of most injuries is not available.209
Although there are basic data on time, place, and person
for some injur ies and deaths , even basic information is
often lacking as to the numbers and characteristics of
people injured and the factors that influence injury
causation, especially in nonfatal events. Detailed
information on the groups that are particularly sus-
ceptible to injuries and their effects is not adequate.
25
OCR for page 26
26
:: -I.:
Injuries from motor-vehicle crashes constitute the
only exception to this limitation.: The incidence.
prevalence, and effects of motor-vehicle injur ies, as
well as measures to counter them, are moderately well
understood, compared with the epidemiology of other
injuries, although even here information about long-term
effects is sparse. The acquisition of knowledge about
motor-vehicle injuries is a direct result of the funding
of research on injury epidemiology from two sources whose
primary mandate is the study of automobile injuries--the
National Highway Traffic Safety Administration and the
Insurance Institute for Highway Safety. Little funding
has been available for research into the epidemiology of
other in jur ies; consequently, our knowledge of these
other in jur ies is slight .
HUMAN FACTORS IN INJURY CAUSATION
Injuries, like diseases, do not occur at random. Some
population groups are at increased risk of injury because
of greater exposure to hazards, decreased ability to avoid
hazards, or decreased resistance to injury, and some
groups have a lower likelihood of complete recovery or
survival once injured.
Age differences between injured and uninjured persons
are substantial injury rates are higher among persons
under age 45, but the elderly and persons aged 15-24 have
the highest injury fatality rates. Other demographic and
social factors also influence the risk of in jury. The
risk of fatal in jury is 2.5 times as great for males as
for females; males are also at greater risk of nonfatal
injury, although by a smaller factor. Fracture rates
are higher in older women, because of the greater
prevalence of osteoporosis or bone decalcification in
thin group. The increased likelihood of fracture of the
hip among the elderly is much greater for women than for
men.
Death rates for many injury categories vary by a factor
of 10 or more among the states. Except for homicide and
suicide, death rates are~highest in rural areas, perhaps
because of differences in socioeconomic status, types of
occupational and other exposures, and lower availability
of prompt emergency care.
Socioeconomic 'status can influence the likelihood of
injury. For example, the incidences of homicide,
assaultive injury, pedestrian fatality, and housefire
OCR for page 27
27
fatality are high among the poor. Although wealth can
place people in high-risk categories for some injury
causes, such as crashes of pr ivate planes and incidents
associated with home pools, the burden of in jury rests
disproportionately on Me poor. High-risk jobs, low-
quality housing, older cars, and such hazardous products
as space heaters tend to be concentrated among poorer
people.~3 2~0 The death rate from unintentional injury
as a whole is twice as high in low-income areas as in
high-income areas. 14
The use and abuse of alcoholic beverages influence the
likelihood of virtually all types of in jury, even among
young teenagers. Almost half of fatally injured drivers
and substantial proportions of adult passengers and
pedestr fans k illed in motor-vehicle crashes--as well as
in falls, drownings, fires, assaults , and suicides--have
blood alcohol concentrations of 0.10 percent or
higher . 2 0 6
In a study of emergency-room patients, alcohol was
detected in 30 percent of the patients injured on the
road, 22 percent in jured at home, 16 percent in jured on
the job, and 56 percent injured in fights or assaults.~97
Contrary to popular perception, alcohol can reduce the
human tolerance to impact and increase the risk of perma-
nent paralysis and other serious injuries. This reduced
tolerance is receiving only scant attention and study.
Understanding this might provide clues to methods of
preventing in jury.
In both highway and nonhighway event';, the more severe
ache event, the higher the percentage in which alcohol
plays a role. Alcoholic-beverage use is involved, for
example, in about 10 percent of property-damage crashes,
about 20 percent of crashes with a serious injury to an
occupant, about 50 percent of all fatal crashes, and
about 60 percent of all single-vehicle fatal
crashes .2 ~ 2 0 4
Other chemicals and drugs have not been shown to play
a causal role in a substantial proportion of injuries,
but some evidence suggests that abuse of amphetamines,
marijuana, or other drugs can seriously impair driving
performance, and individual cases of drug contributions
to crashes have been documented.92 208 Use of multiple
drugs, especially the combination of an alcoholic bev-
erage with one or more other drugs, can create additional
problems. Laboratory studies indicate that many drugs in
co~ranon use--such as benzodiazepines, barbiturates, and
phenothiazines--have a harmful additive or synergistic
OCR for page 28
28
effect when used in combination with alcoholic bev-
erages.' 2 2 o ~ 2 ~ 9 Identifying particular groups of
people likely to drive under the influence of drugs is
especially important for effective preventive efforts;
unfortunately, data for such identification are very
limited.
Numerous studies have attempted to correlate per-
sonality traits and other behavioral factors with
injuries; their results have been of limited practical
use in predicting who will be injured. The bulk of the
evidence suggests that the behavioral factors studied are
very transient.~63 Constant monitoring of those
behavioral factors in the population would be necessary
for identifying persons at acute r isk . Such monitor ing
is not feasible or acceptable in this country.
PRODUCT, WHICLE, ~ TROLL
FACTORS IN INKY CAUSATION
Much more attention has been paid to identifying the
role of people in initiating injury events than to
identifying the role of products, vehicles, and other
environmental factors. Only minimal information is
available on the often subtle interaction of human and
environmental factors in event initiation, because the
necessary epidemiologic studies have never been done.
Specific environmental contributions have occasionally
been identified, BS in motor-vehicle or ho~-pr~uct
investigations leading to either voluntary or compulsory
product recalls. More often, excessive injury experience
is found to be associated with an environmental factor
whose exact role cannot be proved. For example, Utah
uses a dense material to build itch roads, with resulting
low coefficients of friction, and has more wet-weather
crashes in which poor road friction is often a factor--
than do surrounding states, which use a less dense
material. Specific design features have been
associated with high error rates not seen with other
designs. The arrangement of knobs on some stoves, for
exile, makes it much easier for people to turn on the
wrong burner and burn themselves or start a fire than it
is with other knob arrangement. In World War lI,
We reverse positioning of controls for landing gear and
flaps resulted in more than 500 plane crasher.'
More in known about characteristics of specific
environmental and vehicle design and construction
features as determinants of the severity of injury,
OCR for page 29
2g
because of the attention, especially dur ing the last 15
years, to features of motor vehicles and the road environ-
ment that produce or prevent in jury . Some studies have
been particularly successful because they have involved
multidisciplinary approaches based on epidemiology,
clinical medicine, pathology, and biomechanics. The
knowledge gained has led to important interventions, such
as improved door locks and windshield glass, energy-
absorbing steer ing columns, removal of roadside obstacles,
and development of breakaway signs and lam
hosts 3 9 S ~ ~ 2 2 ~ 6 6 ~ 7 ~ But important as - cts repin
largely unknown, and we still need information about
product features that contribute to injury and death in
fires, falls, and recreational and other injuries.
EATS OF ~ INJURY S==IL~CE SYSTEM
Injuries have definable and correctable causes.
Local, state, and federal authorities can make decisions
about how to prevent injuries when they understand the
elements of effective preventive measures and know who is
at high risk, what types of injuries are sustained, the
severity of their consequences, and when, where, and
under what circumstances injuries occur. By comparing
such information over time and among different popula-
tions, they can observe changing patterns of injuries and
identify and implement strategies of intervention. When
specific interventions are carried out, the same informa-
tion can be used to evaluate their effectiveness.
Development of effective intervention strategies
requires an adequate national surveillance system for
monitoring injuries, their causes, and their short-term
and long-term consequences. Continued monitoring of the
most severe injuries and of ~ representative sample of
less revere injuries is an essential component of efforts
to implement and evaluate the effectiveness of measures
to reduce injuries. Table 2-1 lists some typical data
needs for effective injury surveillance. The data listed
would not all be developed in a single surveillance
system, but rather would emerge in a coordinated program
involving several systems ~ some continuous and others
periodic, some simple but geographically broad and others
more complex but limited to a few representative com-
munities. Such a mix of systems can yield necessary
information on which to base and evaluate safety programs
at lower cost and with greater feasibility than a single
complex and continuous surveillance system.
OCR for page 30
30
TABLE 2-1 Examples of Data Needs for Injury Surveillance
Category
Data Needs
Time
Place
Person
Types of in jur ies
Causation
Circumstances
Date and time of in jury event
State, county, city; indoor,
outdoor, road, etc.
Demographic character istics of
in jured and unin jured persons:
age, sex, r ace, SES, phys ical
character istics, occupation,
place of res idence
Types and sever ities of in jur ies
Agents caus ing in j ury; other
mediating factors (such as
vectors and vehicles)
Host factors (alcohol, underlying
diseases, debility), intention
(suicide, homicide, accident),
environmental conditions
( Human-environment mismatch.),
vector-vehicle factors (mater ial
failure , misuse, etc. ),
nonmedical emergency activities
Medical care Resuscitation, EMS, ER, hospitaliza
tion, rehabilitation, long-term
care
Health outcome
Death, amputation, permanent
disability, disability days,
costs, causes of morbidity and
mortality
EXISTING INJURY SURVEILLANCE SYSTEMS
AND THEIR LIMITATIONS
Information on injuries and injury-related events must
be obtained from various sources and through different
means. For example, information on severe injuries may
be available only from hospital records, but information
on vehicle crashes typically originates in police reports.
Moreover many reportable and even serious crashes are not
OCR for page 31
31
reported to the police. A surveillance system aimed at
injury prevention therefore requires a combination of
methods for both gather ing and integrating information
from a variety of sources. It also requires the interest
and ability to carry out a collaborative endeavor among
the several groups that may be collecting or analyzing
the data.
Today, no national system can provide comprebensive
information about injuries and disabilities. Surveil-
lance systems have been important in control ling and
studying other serious health problems, especially
infectious disease and cancer. They involve collection
of data at local, state, and federal levels by such
organizations as the Centers for Disease Control, the
National Cancer Institute, and the separate state cancer
r egistr ies .
Most of the data sources currently available for the
study of injury have serious inadequacies. National
mortality statistics on injuries are collected by the
National Center for Health Statistics (NCHS ) and are
based on the International Class if ication of Diseases
(ICD) codes. ~ 9 9 These codes divide fatal in juries,
according to the apparent intent of the persons involved,
into three categories--unintentional, homicide, and
suicide. They specify injury types and also classify the
events and circumstances related to the injuries. The
current codes are seriously limited; for example, there
is no way to identify work- or recreation-related
deaths. In addition, it is not possible to determine
from NCHS files the location or time of an injury; with
respect to location, only the residence of the deceased
and the place and date of death are specified. Another
problem related to the NCRS mortality data is the delay
(typically about 3 years) in their availability. .
More detailed, and Are useful, mortality data are
collected on all motor-vehicle crash deaths by the
National Highway Traffic Safety Administration (MENSA).
The Fatal Accident Reporting System (FARS ) is a com-
puteriied data base that describes fatal crashes since
1975 on the basis of information collected by agencies in
each state government under contract to NETSA.~27 The
sources include police accident reports, state vehicle
registration files, state driver licensing files, state
highway department files, vital statistics, death cer-
tificates, and coroner or medical examiner reports. The
FARS information, which contains 90 data elements for
each fatal crash, has proved invaluable to researchers
OCR for page 32
32
concerned with reducing motor-vehicle crash deaths and
Injuries ~ ~ '
Recently, MESA began another ma jor data collection
program: the National Accident Sampling System (NASS),
which is designed to produce a nationally representative
sample of all tow-away motor-vehicle crashes. ~ .~ The
NASS uses specially trained crash investigation teas at
50 sites across the country to collect data. Each team
is responsible for collecting detailed information about
the people, vehicles, and environment involved in a sandpile
of motor-vehicle crashes. The resulting data are much
more detailed than those available from police reports.
They include specific hospital and other information on
the injuries involved, as well as on the deformation of
vehicles--information that should be invaluable in
relating vehicle crash forces to the injuries sustained.
The NASS teams investigate about 10,000 crashes a year.
Routinely collected data on nonfatal in jur ies are
seriously limited. As part of the National Health
Interview Survey, NCHS collects information on ire juries,
but the samples are small, details are few, and the data
have only slight utility for epidemiologic research.
The Consumer Product Safety Commission (CPSC) collects
data only on injuries and fatalities associated with most
consumer products (excluding automobiles and work-related
equipment not used in the home). Through the National
Electronic Injury Surveillance System, CPSC collects data
on in jury circumstances and the products involved from
sample of 73 hospitals.~° Occupational injuries were
recently included.
CPSC also collects death certificates involving injury,
but reporting is incomplete and state confidentiality
laws limit the amount and type of information about
products associated with those deaths. To understand the
characteristics of products that are involved in injury,
researchers must have detailed information on the
products. With the notable exception of motor vehicles,
however, most injury reporting systems do not record
brands or models of involved products.
The Occupational Safety and Health Administration
(OSRA) reporting forms do not include the type, manufac-
turer, or model of industr ial machines involved in worker
injuries. When information that might identify a manufac-
turer is part of the CPSC files, it must be expurgated
before the file can be made available to anyone outside
that agency, including those seeking information under
OCR for page 33
33
the Freedom of Information Act, unless the manufacturer
gives permission to divulge the information.
Thus, the only national data on injury and death
related to most products cannot be used to identify the
hazardous characteristics that may be peculiar to, or
most common among, specific brands or modern. This lack
of brand or even gener ic information on products associ-
ated with injuries is clearly a major barrier to the
prevention of injuries. In contrast, the presence of
motor-vehicle identification information in police and
national data f iles , available to private researchers,
has resulted in substantial specification of the charac-
teristics of vehicles that are associated with excessive
crashes either alone or in combination with various driver
characteristics. Recalls of vehicles with modifiable
hazards and changes in designs of new vehicles have
resulted from this free flow of information.
EPIDEMIOLOGIC USES OF INJURY DATA
Surveillance systems can enable identification of
important shifts in patterns of injury or injury complica-
tions; e.g., some occur suddenly or locally and others
occur more slowly or over wider geographic areas. If a
system for identifying the immediate cause of death from
injury had been available, it would hare been apparent
much sooner after World War I] that the immediate cause
of death shifted from abock that resulted from blood loss
to kidney failure, then to respiratory failure, and then
to delayed infection caused by usually harmless organisms
that overwhelm immune mechanisms and cause multiple organ
failure. What each surgeon was identifying as an appar-
entry unique problem involving his patients was in each
of the above modes of death, after considerable delay,
found to be a national trend affecting thousands of
patients.
In contrast, the National Electronic Injury Surveil-
lance System (NEISS), a modest surveillance system
developed by CPSC to identify new injury pattern.,
permitted early identification of a true epidemic of
skateboard injuries and resulted in many local programs
to deal quickly with this; new phenomenon. It also helped
to identify quickly a shift away from skateboards to
skates and thus led to avoidance of safety legislation
that had been predicated on continued growth in the
popularity of skateboards. Surveillance systems should
OCR for page 34
' . !
34
be able to identify and respond to new and potentially
threatening patterns, such as the occurrence of death and
injury resulting from apparent outbreaks of suicide
attempts among students attending specific high schools.
To understand whether a particular product, behavior,
or other factor is hazardous, epidemiologists consider it
essential to know not only about the frequency of its
involvement in injuries, but also whether that frequency
is greater than its frequency in nonin jury situations.
This sort of exposure information is not collected by the
NASS, the NEISS, or OSHA and is collected - only rarely by
most other data collection systems.
A number of states have computerized files of police
crash reports that are available for research purposes.
These files contain little information on injuries.
Typically, motor vehicle-related in jur ies are divided
into only four categories--one for death and three to
cover the entire spectrum of nonfatal injuries. Moreover,
police data tend to underestimate--sometimes substan-
tially--the numbers of injuries that occur.~s Despite
these limitations, police data on crashes are valuable,
especially when relatively great sample size is more
important than detailed injury data.
A variety of specialized data sources for specific
ir,jury t "es, such as burns, are available, but all have
serious limitations for epidemiologic research. Trauma
center registries, for example, are not population-based
and cannot relate their selected cases to less seriously
injured or noninjured populations. Indeed, for nonfatal
injuries, there is no alternative to specially focused
and often expensive data collection projects. Little is
known about the less severe injuries that cause most of
the visits to physicians and restriction of normal
activities. The long-term consequences of what may
appear to be minor injury are essentially unknown. For
example, the long-term effects of brain injuries that
initially are considered minor are unknown, although data
from recent studies of boxers suggest that even apparently
minor head injury can have serious long-term
seque}ae.~ ask
Many types of injuries produce a wide range of chronic
disabilities, but the long-term impact of injuries in the
United States is unknown. For many other health problems,
such as cancers and cardiovascular diseases, long-term
longitudinal studies have prc~ided valuable epidemiologic
data on which to base intervention strategies. There is
OCR for page 35
35
every reason to believe that similar studies of injuries
would yield similarly valuable information.
High-quality epidemiologic data are essential for the
planning, development, and evaluation of efforts to
prevent injuries. Despite this essential intertwining of
epidemiology and prevention, many preventive activities
have not been based on epidemiology; nor have they been
evaluated epidemiolog ically. For example, the huge
federal effort supporting high-school driver education as
a means of reducing injuries was not evaluated before
such education was greatly increased. More than 10 years
later, research showed that dr iver-education programs
actually increased injuries by encouraging teenagers to
drive earlier and that such education did not reduce the
crash involvement of those trained. 6 3 Valuable
resources were wasted, because the interventions chosen
were not based on adequate data or sound epidemiology.
However, even with limited resources for research into
injury control, considerable advances in the state of
knowledge have been made in specific cases, through sound
research based on adequate data and epidemiologic
principles. Many more such advances involving a wide
range of injuries are possible.
For almost any generally homogeneous set of injuries
that has been studied, it has been possible to identify
factors that greatly increased risk and factors that
could be changed. For example, when children's fatal
falls in New York City were studied in adequate detail,
researchers found that such fatalities resulted mainly
from falls from windows in multistory buildings. Fatal
falls of children were reduced ';ub';tantially by an inter-
vention program that combined distribution of window
cover ings, education regarding the problem, and required
use of the coverings by landlords.
Drowning is an example of a phenomenon on which more
ref. ined epidemiologic knowledge than is now available is
needed, if better prevention strategies are to be devel-
oped. To prevent drowning, information in needed about
the bodies of water involved, the activities of the
drowned persons and others in their company at the time
of the drownings, and the environmental conditions. If
most children who drowned wandered alone into unfenced,
unattended swimming pools, the appropriate intervention
strategy would be different from that if most children
who drowned did so because they played in streams or
ponds. Unfortunately, where data are available at all ,
OCR for page 36
36
this kind of specification of circumstances is usually
not included.
Injur ies and injury-related deaths can be greatly
reduced in the next several decades. The reductions will
require substantial programs of national surveillance,
epidemiologic analysis, and evaluation. Ma jor research
questions that could be addressed with proper epidemio-
logic data are discussed in the next chapter.
RECOMMENDATIONS
1. The United States requires effective injury sur-
veillance systems for gather ing and integrating informa-
tion from a variety of sources on which to base the
planning and evaluation of control efforts. This would
include long-term longitudinal studies of in juries and
the co' lection of more refined data on specific types and
causes of injuries and exposures to injurious
environments.
2. A national capacity should be developed for the
quick identification and control of outbreaks of specific
Incur yes.
3. A consistent and accurate system for coding the
causes of injuries needs to be used by hospitals.
4. Research is needed to determine the short- and
long-term costs of injuries.
Representative terms from entire chapter:
jur ies
