Identifying Factors Underlying InjuryThomas Songer, PhDUniversity of PittsburghCenter for Injury Research & ControlMoving Towards Competency in Injury PreventionLecture Objectives1. Describe how conceptual models can be used to investigate and portray the multiple factors underlying injury and/or violence2. Explain the importance of collaboration in prevention efforts3. Describe the influence of a variety of factors on injury preventionOn completion of this lecture, …you as a reader and listener should be able to:Core Competencies for Injury and Violence Preventionwww.injuryed.orgCore Competency #1:Ability to describe and explain injury and/or violence as a major social and health problem.I. Using Models to Identify Risk Factors for Injury and Approaches to Injury PreventionWhat comes to mind when you see or hear the term “model”?• Model - (def): schematic description of a system, theory, or phenomenon that accounts for its known or inferred properties and may be used for further study of its characteristicsInjury as a complex system• An injury (event) can be viewed as involving several factors and processes• Thus, injury prevention can be approached by using multiple types of interventions that focus on one or more of these events8Domino Theory of Accidents• HW Heinrich; “injury is the natural culmination of a series of events or circumstances which occur”In Heinrich’s Domino Theory, accidents are viewed to result from a chain of sequential events, similar to a line of dominoes falling over. Removing one of the key events prevents the full chain reaction, and the occurrence of an injury.H. W. Heinrich, “Industrial Accident Prevention: A Scientific Approach” (1950).Heinrich Domino TheoryAncestry & Social EnvironmentFault of PersonUnsafe Act or ConditionAccident InjuryEventInjury Factor aFactor bUnsafeConditionFactor cConceptual Models in Injury PreventionTheory/Models Guiding Injury and Violence Prevention• Epidemiologic Model• Public Health Model• Haddon Model/Matrix• Social-Ecologic Model• Safety Promotion ModelThe Factors UnderlyingInjuries can be examined from an Epidemiologic FrameworkThe visionary of injury epidemiology and injury control was William Haddon. Dr. Haddon was the director of the National Highway Traffic Safety Administration and the Insurance Institute for Highway Safety in the 1960s and 1970s. He used these positions to play a leading role in the cause of traffic safety. The basis behind his work was the simple argument that injuries can be examined within an epidemiologic framework. In it’s classic sense, the epidemiology triad considers the interaction of three factors in the development of disease; the host, the agent, and the environment. Dr. Haddon maintained that these factors also were key elements in the development of injuries.HostEnvironmentAgent – Energy TransferJohn Gordon was also one of the first investigators to view injuries from the epidemiologic triad of host, agent, environment. Initially, the agent of injury was viewed as the object involved (e.g. the car, the piece of machinery, the knife, etc.). In subsequent years, though, the agent of injury was properly understood to be the energy transfer involved in the event. James Gibson generally receives the credit for this insight. The object involved (such as the automobile), then, came to seen as the vehicle through which the energy transfer was enabled. William Haddon subsequently refined this aspect of injury control further.Risk factors for motor vehicle crashesHumanEnvironmentalVehicularFailureDesignSpeedAgeGenderExperienceAlcoholFatigueRoad ConditionsTrafficWeatherFurther illustration of the epidemiology triad and an evaluation of injuries from motor vehicles crashes is presented here. A key element in Dr. Haddon’s work was the contention that the epidemiologic framework couldbe used to identify risk factors for injuries. Moreover, these risk factors were not just those related to the host, but also those pertaining to the vehicle, and the road (environment).Several programs follow the publicmodel for disease control in understanding injuries; their occurrence and their preventionA second basic principle of injury epidemiology is the general framework that shapes the work of researchers in the injury epidemiology field. This framework is called the “Public Health Model for Disease Control”.Public Health Model for Disease ControlMonitoring ofconditionIdentifyrisk factorsIntervene EvaluateIdentifymorbiditymortalitycostsocialgeneticenvironmentalhealth care17Most injury prevention efforts are based on the Haddon MatrixThe Haddon MatrixHuman Vehicle EnvironmentPre-eventEventPost-eventTo understand the factors underlying injuries from motor vehicle accidents, Haddon proposed that the elements of the epidemiology triad should be considered in unison with the crash sequence. The crash sequence can be examined in terms of three items; the circumstances surrounding the event prior to the crash occurring, the circumstances involved during the crash, and those involved after the crash. The Haddon Matrix illustrates how the crash sequence interacts with human, environment, and vehicular factors to define the frequency and severity of injury.Haddon MatrixPost-eventEventPre-eventSocial Environ.Physical Environ.Vehicle/Vector PersonFactorsPhasesThe Haddon MatrixPost-EventEventPre-EventSocial/Cultural EnvPhysical EnvironmentVector(Vehicle)Host(Human)Phase/FactorWill an event with the potential to cause injury occur?Will an injury occur?What will the outcome be (e.g. how severe)?Haddon’s Matrix Slides Adapted From: Community Action Training, Community Health Education Section, San Francisco Department of Public Health, 6/4/02So the goal in using Haddon’s matrix is to identify major modifiable factors that lead to unhealthy outcomes. And when we look at the matrix itself, you can see it is divided into a series of cells. Each of these cells represents an opportunity to think through the prevention possibilities, and encourage you not to devote all of your attention to one or two cells on the matrix.For Factors, we have the host, vector, physical and social or cultural environment. Then we have the phases in this column. And remember this matrix is to get you thinking about the variety of interventions that occur, and to hopefully help you see that you should not be dedicating all of your resources to one cell, such as pre-event education