ACCIDENTS

In more precise language, accidents should be referred to as "unintentional injuries." The contention over the use of the word accident has to do with the

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issue of preventability. In common usage, the term accident implies that the event was random and nonpreventable. But for "accidents," whether resulting in death or lesser injury, such an implication is incorrect, hence the term accident is best avoided. In June 2001, the British Medical Journal took the position of "Banning the inappropriate use of 'accident' in our pages" (Davis, p. 1,320). Injuries may be intentional or unintentional. This article focuses on the latter category.

Definition

Injury events are those in which "(1) injury occurs over a relatively short period of time–seconds or, at most, minutes, (2) the harmful outcome was not sought, and (3) the injury resulted either from one of the forms of physical energy in the environment (kinetic, chemical, thermal, electrical, or ionizing radiation) or because normal body mechanisms for using such energy were blocked by external means (such as drowning)" (Waller, p. 8). Unintentional injuries may be described simply as "unforeseen incident(s), where the intent to cause harm, injury or death was absent, but which resulted in injury" (International Classification of External Causes of Injury).

How Injury Is Classified

The World Health Organization's (WHO) International Classification of Diseases (ICD) specifies codes for diseases and injury. Injury, unlike diseases or natural causes, is captured by two distinct sets of codes, those for the nature of the injury and those for the external causes of the injury. For external causes, a single code is assigned that combines both the intentionality or manner of the injury and the

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mechanism or cause of the injury. The intent of injury takes precedence in the classification, with mechanism of injury being coded within an intent category. The manner of the injury can be unintentional or "accidental," intentional (including self-inflicted and assault injuries), or of undetermined intent. For data presentation purposes, a standard framework based on groupings of ICD external cause of injury codes allows for data to be examined separately by intent as well as by mechanism.

The ICD is limited because it is a onedimensional code system (a single code describing intent and cause) and because external cause codes often lack the specificity needed for designing or monitoring injury prevention and control activities. Hence, injury professionals around the world, under the auspices of the World Health Organization, have worked to develop a new multidimensional system for classification, the International Classification of External Causes of Injury (ICECI). The ICECI has the flexibility of coding in settings where minimal data are available as well as in those settings with great detail.

Scope

WHO estimated that there were 3.4 million unintentional injury deaths worldwide in 2000, accounting for 6 percent of all deaths and for two-thirds of all injury deaths. Deaths of males comprised 2.3 million, or two-thirds, of the unintentional injury deaths. Table 1 shows the main causes of death from unintentional injury, on a global basis and categorized by gender, in 2000. There is relatively little regional variation in unintentional injury mortality, with crude death rates ranging from lows of 44 to 50 deaths per 100,000 population per year in the Americas, the Western Pacific, and the Eastern Mediterranean to highs of 69 in Africa and Southeast Asia. Within-region variation can be much higher, however, and was most pronounced in Europe where mortality ranged from an average of 34 in countries with very low child and adult mortality to 117 where adult mortality was very high. In every region except for Europe, road traffic accidents accounted for 30 to 40 percent of all unintentional injury mortality. In Europe they accounted for 24 percent, with deaths from poisoning accounting for 21 percent.

Table 2 shows the unintentional injury death rates in the United States and selected other developed countries. To facilitate comparisons the rates here and below are age-standardized to remove the effects of differences in age distribution. In each country with the exception of Denmark, motor-vehicle traffic deaths were the leading cause of unintentional injury.

U.S. Fatal Injuries

In 1999, 97,860 persons resident in the United States died as the result of an unintentional injury. The death rate in 1999, 35.9 deaths per 100,000 population, was 23 percent lower than in 1979 and 54 percent lower than in 1950 (see Figure 1). Unintentional injury ranked as the fifth-leading cause of death for all ages in 1999, accounting for 4 percent of all

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FIGUR 2

deaths. (The four causes ranked above it were diseases of the heart, malignant neoplasms, cerebrovascular diseases, and chronic lower respiratory diseases.) In contrast, homicide (16,889 deaths) and suicide (29,199 deaths) did not rank in the top ten causes of death.

Among all causes of death in the United States, unintentional injury ranked fourth among males and seventh among females, and third to fifth across racial and ethnic groups. By age, unintentional injury was the leading cause of death for persons 1 to 34 years of age, ranked second for those 35 to 44, and ranked third for persons 45 to 54. As seen in Figure 2, the age distribution of unintentional injury includes three relatively distinct peaks–for infants, for older teens and young adults, and among the elderly.

Motor-vehicle traffic injuries continue to be the leading cause of unintentional injury death for persons 1 to 74 years of age. Between 1979 and 1999, declines in death rates from motor-vehicle traffic injuries were responsible in large part for the overall decline in unintentional injury mortality. For infants, suffocation causes more deaths than other kinds of unintentional injury, and for persons 75 years and older, falls rank highest. For persons 25 to 54, poisoning is one of the leading causes of unintentional injury death.

Nonfatal Injuries

Nonfatal unintentional injuries are more difficult to measure than fatal injuries because, unlike the case of deaths, there is no complete count of them. Usually nonfatal injuries are measured by nationally representative sample surveys, primarily of medical records. Estimates rely on what is written in the patient's medical record, and because health-care providers are often under time pressure, documentation of intent can easily be affected. When intent is not precisely stated, coding often defaults to "unintentional." Thus, estimates of unintentional injury based on surveys are likely to have an upward bias.

In the United States in 1999, there were an estimated 29.3 million visits to emergency departments for unintentional injuries, accounting for about 30 percent of all emergency department visits. In general, visit rates were higher for the younger and older populations than for the middle-aged. Falls were the leading external cause of emergency department visits, followed by motor-vehicle traffic injuries, injuries from being struck by or against an object or person, and injuries from instruments used for cutting or piercing.

Hospital admissions for unintentional injuries are less frequent than emergency department visits. In the United States, during 1998-1999, approximately 6 percent of emergency department visits for an unintentional injury resulted in an admission to the hospital with percentages ranging from about 3 to 4 percent for those younger than 45 years to upwards of 25 percent for those 75 years and older. Falls and motor-vehicle-related injuries are the leading external causes of unintentional injury resulting in hospitalization.

Estimates of the numbers of unintentional injuries and deaths in the United States are produced by the National Center for Health Statistics of the Centers for Disease Control and Prevention (CDC). Additional data on nonfatal injuries are produced by the National Electronic Injury Surveillance System (NEISS) of the U.S. Consumer Product Safety Commission. Prevention of unintentional injuries and deaths falls within the activities of the CDC's National Center for Injury Prevention and Control.

BIBLIOGRAPHY

Anderson, Robert N. 2001. "Deaths: Leading Causes for 1999." National Vital Statistics Reports 49(11). Hyattsville, MD: National Center for Health Statistics.

Centers for Disease Control and Prevention. 1997. "Recommended Framework for Presenting Injury Mortality Data." Morbidity and Mortality Weekly Report 46(RR–14): 1–30.

Davis, Ronald M., and Barry Pless. 2001. "BMJ Bans 'Accidents': Accidents Are Not Unpredictable" (editorial). British Medical Journal 322: 1,320–1,321.

Fingerhut, Lois A., and Elizabeth McLoughlin. 2001. "Classifying and Counting Injury." In Injury Control: A Guide to Research and Program Evaluation, ed. Fred P. Rivara, Peter Cummings, Thomas D. Koepsell, David C. Grossman and Ronald V. Maier. New York: Cambridge University Press.

Hoyert, Donna L., Elizabeth Arias, Betty L. Smith, Sherry L. Murphy, and Kenneth D. Kochanek. 2001. "Deaths: Final Data for 1999." National Vital Statistics Reports 49(8). Hyattsville, MD: National Center for Health Statistics.

Institute of Medicine. 1999. Reducing the Burden of Injury: Advancing Prevention and Treatment, ed. Richard J. Bonnie, Carolyn E. Fulco, and Catharyn T. Liverman. Washington, D.C.: National Academy Press.

McCaig, Linda F., and Cathy W. Burt. 2001. National Hospital Ambulatory Medical Care Survey: 1999 Emergency Department Summary. Hyattsville, MD: National Center for Health Statistics.

Pless, Barry 2001. "Banning Accidents: An Addendum." Injury Prevention 7: 169–170.

Waller, Julian A. 1985. Injury Control: A Guide to the Causes and Prevention of Trauma. Lexington, MA: Lexington Books.

World Health Organization. 1992. International Statistical Classification of Diseases and Related Health Problems, 10th rev. Geneva, Switzerland: World Health Organization.

INTERNET RESOURCES.

Centers for Disease Control and Prevention. National Center for Health Statistics. 2002. <http://www.cdc.gov/nchs/>.

Centers for Disease Control and Prevention. National Center for Injury Prevention and Control.2002. <http://www.cdc.gov/ncipc/>.

Consumer Product Safety Commission. National Electronic Injury Surveillance System (NEISS).2003. <http://www.cpsc.gov/about/clrnghse.html>.

International Classification of External Causes of Injury. 2002. <http://www.iceci.org/>.

World Health Organization. 2001. "World Health Report 2001: Statistical Annex." <http://www.who.int/whr/2001/main/en/annex/index.htm>.