From the public health perspective, injury is not considered an “accident” but rather a disease, much like malaria, tuberculosis and other public health scourges, or cancer and heart disease. Injury, like other diseases, has variants such as blunt or penetrating. It has degrees of severity, rates of incidence, prevalence, and mortality that can differ by race and other sociodemographic factors. Injuries have a pattern of occurrence related to age, gender, alcohol and other drugs, and again, sociodemographic factors, among others.
When public health concepts are applied to this disease of injury, it, like the aforementioned public health diseases, can be controlled to a socially acceptable level. The first step, however, is to characterize the disease such that control strategies can be applied. Epidemiology is the study of patterns of disease occurrence in human populations and the factors that influence these patterns.1
Descriptive epidemiology refers to the distribution of disease over time, place, and within or across specific subgroups of the population. It is important for understanding the impact of injury in a population and identifying opportunities for intervention.
Analytic epidemiology, in contrast, refers to the more detailed study of the determinants of observed distributions of disease in terms of causal factors. The epidemiological framework traditionally identifies these factors as related to the host (i.e., characteristics intrinsic to the person), the agent (physical, chemical, nutritive, or infectious), and the environment (i.e., characteristics extrinsic to the individual that influence exposure or susceptibility to the agent). The environment can be physical or sociocultural.
It is the understanding of how these multiple factors interact to increase the risk of injury and their influence on injury outcome that exemplifies the epidemiological approach to the study of disease and injury. By studying patterns of occurrence across and within populations of individuals, one can learn how best to potentially mitigate them. The concepts of the public health approach applied to injury control seek to modulate factors related to the host and agent and/or their interactions within the environment utilizing a number of strategies. These strategies encompass engineering, education, the enactment and enforcement of laws, and economic incentives and disincentives.
Injuries can result from acute exposure to physical agents such as mechanical energy, heat, electricity, chemicals, and ionizing radiation in amounts or rates above or below the threshold of human tolerance.2 The transfer of mechanical energy accounts for more than three quarters of all injuries.3 The extent and severity of injury is largely determined by the amount of energy outside the threshold of human tolerance. Both the exposure to energy and the consequences of that exposure are greatly influenced by a variety of factors both within and beyond individual or societal control.4
The public health approach as it applies to injury was first conceptualized by William Haddon in the late 1960s.2 He developed and promulgated a phase-factor matrix that incorporated the classic ...