Injury: Magnitude and Characteristics of the Problem

Injury is caused by acute exposure to energy, such as heat, electricity, or the kinetic energy of a crash, fall, or bullet. It may also be caused by the sudden absence of essentials, such as heat or oxygen, as in the case of drowning. Injury may be either unintentional (accidental) or deliberate (assaultive or suicidal).

Each year, more than 140,000 Americans die from injuries and 70 million sustain nonfatal injuries. Injury causes almost half the deaths of children aged 1-4, more than half the deaths of children aged 5-14, and nearly four-fifths of the deaths of persons aged 15-24 (Figure 1). Thus, injury is the leading cause of death among children.

Figure 1

Percentages of deaths from injury and other causes in the United States in 1980, by age. Modified from Baker, S. P., B. O'Neill, and R. Karpf. The Injury Fact Book (Lexington, Mass.: Lexington Books, 1984).

As infectious diseases have come under control during the last century, the relative importance of injury has increased to the point where it is now the most prominent cause of death for more than half the human lifespan (ages 1-44). For more than three decades of life (ages 1-34), motor-vehicle crash injuries alone are the leading cause of death. For all ages combined, the injury death rate is surpassed only by the rates for heart disease, cancer, and stroke.

Injury greatly surpasses all major disease groups as a cause of prematurely lost years of life, because it is the preeminent cause of death among children and young adults. More years of future worklife are lost to injury than to heart disease and cancer combined. Each year, over 4 million years of future worklife are lost to injury, compared with 2.1 million to heart disease and 1.7 million to cancer (Figure 2). The impact of nonfatal injury is of similar proportions.

Figure 2

Percentages of years of potential life lost to injury, cancer, heart disease, and other diseases before age 65. Modified from Centers for Disease Control. Table V. Morb. Mort. Weekly Rep. 31:599, 1982.

Injury is the leading cause of physician contacts. It is the most common cause of hospitalization among people less than 45 years old. The personal, family, and societal costs of mental and physical disability and disfigurement are huge.

Although injury is the most costly of all major health problems (about $75-$100 billion per year), support for injury research has been minimal. The total annual expenditure for injury-related research by the National Institutes of Health (NIH), about $34 million, is less than 2 percent of the NIH research budget. The total expenditure by all nonmilitary federal agencies is about $112 million—less than $2 for every $1,000 of the cost of injuries themselves.

Epidemiology of Injury: the Need for More Adequate Data

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. Although there are basic data on time, place, and person for some injuries 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 susceptible to injuries and their effects is not adequate. Injuries from motor-vehicle crashes constitute the only exception to this limitation. The incidence, prevalence, and effects of motor-vehicle injuries, 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 injuries; consequently, our knowledge of these other injuries is slight.

Continuous, systematic data collection is essential for planning and evaluating preventive programs. The lack of appropriate data systems has led to the institution of some expensive but ineffective preventive programs.

Prevention of Injury

Injuries can be prevented with a variety of strategies. The effectiveness of these strategies varies inversely with the extra effort required to keep people from being harmed and the degree to which people must change their usual behavior patterns.

Three general strategies are available to prevent injuries:

• Persuade persons at risk of injury to alter their behavior for increased self-protection—for example, to use seatbelts or install smoke detectors.
• Require individual behavior change by law or administrative rule—for example, by laws requiring seatbelt use or requiring the installation of smoke detectors in all new buildings.
• Provide automatic protection by product and environmental design—for example, by the installation of seatbelts that automatically encompass occupants of motor vehicles or built-in sprinkler systems that automatically extinguish fires.

Each of these general strategies has a role in any comprehensive injury-control program; however, a basic finding from research is that the second strategy— requiring behavior change—will generally be more effective than the first, and that the third—providing automatic protection—will be the most effective. A fundamental reason for this is that members of high-risk groups tend to be the hardest to influence with approaches that involve either voluntary or mandated changes in individual behavior. Teenagers, for example, are much less likely than adults to wear seatbelts, whether or not a law requires them to do so. Programs intended to change alcohol-related behavior voluntarily have not produced sustained reductions in death rates. Elderly pedestrians admonished by police for jaywalking were no less likely to do it again. Scofflaw drivers whose licenses had been revoked were more likely than the average licensed driver to be involved in fatal crashes. And not only are young children hard to influence, but intensive efforts at a well-baby clinic, for example, had no effect on dangerous maternal behavior, such as leaving knives and matches within the reach of small children.

The shortage of health professionals and scientists with relevant training is a major impediment to injury control. Without knowledgeable and interested persons trained in the relevant sciences, the injury toll will continue ·

Injury Biomechanics Research and the Prevention of Impact Injury

Impact injury of the human body occurs by deformation of tissues beyond their failure limits, which results in damage of anatomic structures or alteration in normal function. Injury biomechanics research uses the principles of mechanics to explore the mechanisms of physical and physiologic responses to impact, including both penetrating and nonpenetrating blows to the body. Although injury can occur by slow deformation, in crushing, the predominant feature of impact injury is the fast, violent nature of the event, whether it is the rapid impact of a person's chest on the instrument panel of an automobile or a bullet's penetration of the chest cavity.

Improved protection could be realized with a better understanding of the biomechanics of injury and disability. Design of less injurious environments depends partly on knowledge of the effects of specific kinds and amounts of energy on specific human tissues. Although we know the approximate limits of forces that can be tolerated by young healthy males in rapid deceleration, we do not have refined data on other elements of the population, on the extent of reversibility of damage, or on effects on nervous tissues or tissues outside particular size and structural ranges.

Treatment

Except when death occurs immediately, the outcome of an injury depends not only on its severity, but also on the speed and appropriateness of treatment. Communication systems are needed to facilitate decision making, injury management at the site, and the rapid delivery of the patient to a hospital that can provide the needed care.

Once a severely injured person arrives at a hospital, treatment requires the effort of a team that includes specialists in various aspects of injury management. Designated trauma centers with experienced teams available and necessary backup facilities, such as well-stocked blood banks, are essential. In addition to the development and evaluation of such systems, there is a need to ensure that patients treated in hospitals other than trauma centers receive the most up-to-date care, so that unnecessary morbidity, mortality, and residual disability are avoided.

The most important topic to be addressed with regard to treatment is control of swelling of the brain; improvements could substantially reduce injury mortality. Understanding of the immune system and prevention and control of infection also warrant high priority as does control of spinal cord swelling and research in spinal cord regeneration.

Rehabilitation

Rehabilitation is the process by which physical, sensory, and mental functional capacities are restored or developed after damage. In the context of injury control, rehabilitation is the process by which biologic, psychologic, and social functions are restored or developed to permit an injured person to achieve maximal personal autonomy and an independent noninstitutional lifestyle. Rehabilitation is achieved not only through functional change in the person (e.g., development of compensatory muscular strength, use of prosthetic limbs, and treatment of postinjury behavioral disturbances), but also through changes in the physical and social environment, such as reductions in architectural and attitudinal barriers that hamper those requiring use of a wheelchair.

In the last decade, improvements in emergency medical systems, in immediate management by trauma centers, and in care of the injured en route to hospitals have increased the survival of persons with nervous system injuries, multiple injuries of the musculoskeletal system and viscera, or extensive burns. Trauma units have increased the need for defined referral to special rehabilitation programs and follow-up services. More persons survive major injuries, and survivors often have severely disabling effects from the injuries themselves and from uncreated complications. Many need functional restoration of cognition, sensation, movement control, and mobility after brain, spinal cord, and musculoskeletal injury. Further negative effects on health and performance in daily life that result from the loss of body parts and from inactivity and immobility must be prevented.

Preventable disability is not an uncommon consequence of inadequate management of the injury patient—for example, limitation of motion due to contracture in burned patients or paralysis in patients with unrecognized injury of cervical vertebrae. Pressure sores, or ''bedsores,'' are an entirely preventable complication that occurs in 35-40 percent of persons with spinal cord injury, at an average cost of $25,000-$28,000 per pressure sore, inestimable misery, and increased debilitation.

With comprehensive care, the profound biologic, psychologic, and social responses to paralysis and movement disorders, disfigurement, and loss of body parts are controllable to a remarkable extent. Although limited resources for clinical programs have been provided through private and publicly supported efforts, parallel research and educational resources for the development and dissemination of knowledge and technology have been seriously inadequate. The development of expanded special regional centers and programs has been lacking for the large number of unserved persons who could benefit.

Current Federal Expenditures for Injury-Related Research

To assess federal support for injury-related research, the committee reviewed federal research expenditures for fiscal 1983.

The total federal expenditures for nonmilitary research on injury were approximately $112 million in fiscal 1983. Expenditures in 1 year are more relevant when compared with other expenditures in the same year. For example, although injury research in fiscal 1983 accounted for approximately $34.4 million of expenditures at the National Institutes of Health (NIH), that was less than 2 percent of the total NIH research budget. Although injuries are responsible for the loss of more economically productive years of life than heart disease and cancer combined, the federal expenditure for research in injury control is relatively small—approximately one-tenth of that for cancer and less than one-fifth of that for heart disease and stroke (Figure 3). Thus, when one compares the relative research expenditures and the years of life lost to these causes of death before age 65, it is apparent that the smallest portion of the funds is being allocated to the largest problem—injury.

Figure 3

Preretirement years of life lost annually and federal research expenditures for major causes of death in the United States. Years of life lost derived from age-at-death distributions in the National Center for Health Statistics Vital Statistics of the (more...)

The committee believes that substantial decreases in current injury rates would result from research requiring substantially less support than is now expended on cancer and cardiovascular disease. An increment in current funding with close monitoring of the application of the research results could illustrate the investment value of such expenditures for the entire population.

The committee does not advocate a reduction in federal expenditures for health research in cancer or heart disease and stroke. It does feel, however, that federal expenditures for injury research and injury control are seriously inadequate. The committee believes that substantial progress could be made in the reduction of the incidence of injury and its associated morbidity and mortality if adequate funding, direction, and support were given to a coordinated federal program of injury research.

Administration of Injury Research

The committee discussed the advantages and disadvantages of various models for managing injury research in the federal government. Criteria were established for a unit that could effectively manage a large-scale federal program in injury research, and the selected models were compared for suitability. After consideration of the various alternatives, the committee recommended the establishment of a new "Center for Injury Control" (CIC) in the Centers for Disease Control (CDC). The function of the Center for Injury Control would be to carry out a national injury research program in the following manner:

• Support research in biomechanics, injury epidemiology and prevention, acute care, and rehabilitation.
• Establish injury surveillance systems and conduct injury prevention projects.
• Improve and expand professional education and training.
• Establish centers of excellence in injury biomechanics, prevention, and care.
• Collect and analyze data on injury.
• Serve as a clearinghouse and lead agency among federal agencies and private organizations interested in injury research and prevention.

The structure of CIC is visualized along the lines of the diagram in Figure 4. Divisions dedicated to the major sectors of needed research—epidemiology, prevention, biomechanics, acute care, and rehabilitation—would be coordinated by a director. The CIC director would report administratively to CDC and would convene an advisory council consisting of representatives of federal agencies and other organizations engaged in injury research.

Figure 4

Suggested location and organizational structure of proposed center for injury control.

The CIC director and staff would review priorities, establish specific research goals, identify scientists capable of implementing the research, and coordinate peer review. It is imperative that all appropriate disciplines be represented and that the CIC director be a scientist with recognized research accomplishments and successful experience in interdisciplinary investigations of injury. No single discipline or disciplinary orientation can produce the broad spectrum of research needed for injury control.

Clearinghouse and coordinating functions in CIC are essential, although the injury research problem is much more than a matter of insufficient coordination.

CIC should foster and support research directed to filling the knowledge gaps that inhibit the control of injury. To do this, it should contain special study sections and a granting mechanism in each that would provide for continued, rather than year-by-year, funding of research projects. Funding should cover demonstration programs, multiple centers of excellence, and training of researchers in appropriate fields. CIC funds should supplement, rather than replace, funds currently allocated to other agencies, such as the Department of Transportation (DOT), the Department of Defense (DOD), and NIH; and their funding related to injury research should not be channeled through CIC.

The director and the advisory council should be charged with the development of an annual plan and report to Congress—an approach similar to that followed by the National Toxicology Program. This administrative mechanism would encourage the CIC director and representatives of other agencies to consider the scope of what is being done, in view of the various agency mandates, and to avoid inappropriate duplication of effort.

An independent review of CIC should be conducted within 5 years of its establishment to assess its progress in accomplishing the objectives recommended in this report. At that time, consideration should also be given to the elevation of this center to independent agency status.

Injury is the major health problem facing young Americans today. The opportunity exists to create a focused, coordinated research effort with the potential to save lives, improve productivity, and reduce costs and long-term losses to the injured, their families, and society. The alternative is the continued loss of health and life to predictable, preventable, or modifiable injuries. The committee firmly believes that it is time to plan and undertake a national program to address this problem.