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Injury Epidemiology

Injury Epidemiology. Moving from Descriptive to Analytic Research Approaches. Thomas Songer, PhD University of Pittsburgh tjs@pitt.edu. readings. Learning objective. To differentiate between various study designs used in injury epidemiology. Background.

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Injury Epidemiology

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  1. Injury Epidemiology Moving from Descriptive to Analytic Research Approaches Thomas Songer, PhD University of Pittsburgh tjs@pitt.edu readings

  2. Learning objective • To differentiate between various study designs used in injury epidemiology

  3. Background • Epidemiology looks to control or prevent disease • In this endeavor, epidemiology seeks to • describe the frequency of disease and it’s distribution • consider person, place, time factors • assess determinants of disease • consider host, agent, environment

  4. Types of primary studies • Descriptive studies • describe occurrence of outcome • Analytic studies • describe association between exposure and outcome

  5. Basic Question in Analytic Epidemiology Are exposure and disease linked? E D Exposure Disease

  6. Big Picture • To prevent and control disease • In a coordinated plan, look to • identify hypotheses on what is related to disease and may be causing it • formally test these hypotheses • Study designs direct how the investigation is conducted

  7. A Model of Injury Control Identify risk factors Monitor incidence Intervene Evaluate Descriptive Analytic

  8. What designs exist to identify and investigate factors in injuries?

  9. Descriptive Analytic Case report Cohort study RCT Case-Control Case series study Study Designs Descriptive Epidemiology Case-Crossover study Cross-sectional study Before-After study Ecologic study

  10. Framework for Understanding Injuries Cohort Studies Case- Control Studies Increasing Knowledge of Disease/Exposure Cross- Sectional Studies Case Series 1982 84 86 88 90 92 94 1996

  11. Develop hypothesis Descriptive Studies Investigate it’s relationship to outcomes Case-control Studies Increasing Knowledge of Disease/Exposure Define it’s meaning with exposures Cohort Studies Test link experimentally Clinical trials

  12. Descriptive Studies

  13. Injury Surveillance

  14. Descriptive Studies - An Example The Rockets' Red Glare, the Bombs Bursting in Air: Fireworks-related Injuries to Children. Pediatrics 98(1):1-9, 1996

  15. EMS Police Self-Treat Emergency Dept. doctor Injury Hospital Morgue Trauma Center Rehab Center Robertson, 1992

  16. Data Sources and Injury Severity No injury Mild Moderate Severe Fatal Survey Doctor visit Hospital admiss. Trauma center Death certificate Rogams, 1995

  17. One case of unusual injury finding Case Report Multiple cases of injury finding Case Series Descriptive Epidemiology Study Population-based cases with denominator

  18. Causes of Death in Travelers Cardiovascular Injury Medical Cancer Suicide/Homicide Other Hargarten, 1991

  19. Study design Definition of injury Data Sources Population Bias Findings Descriptive study ED visits CPSC-NEISS, IPII (fatal) United States reporting of scooters scooter related injuries have increased over the last 2 yrs Scooter Injuries http://www.cdc.gov/mmwr/preview/mmwrhtml/mm4949a2.htm

  20. Descriptive Studies Analytic Studies

  21. Case-Control Studies Cases: injured Controls: not injured

  22. Case-Control Studies - An Example Characteristics of Fatally Injured Pedestrians Cases Controls Blood Alcohol Concentration No. % No. % None 3 17.6 13 76.5 10-40 5 29.4 1 5.9 50-90 1 5.9 1 5.9 100-140 2 11.8 1 5.9 150-190 5 29.4 - 0.0 200-240 1 5.9 - 0.0 Lab loss - 0.0 1 5.9

  23. Cohort Studies Cases: have exposure Controls: no exposure

  24. Cohort Studies - An Example Rates & Risks of Youth Sports Injury in Allegheny County

  25. Limitations of Existing Studies • Do not take into account the injury risk among non-participants, cannot determine the relative risk of sports participation • Do not quantify the “exposure” or the “dose” of activity, do not know the risk of injury per “activity hour”

  26. Allegheny County Adolescent Injury Surveillance Cases: high physical activity Controls: low physical activity 3 years Baseline

  27. Injury Surveillance • Continuous surveillance - 3 years • Quarterly screening of students during physical education class. • Collected detailed injury information. • Type, diagnosis, treatment, location. • Validated by parent - 92% • Random sample of medical records

  28. Definitions • Injury • Any event that produced bodily damage and required treatment by medical personnel (MD, ED, Specialist, Hospitalization) • Severe Injury • any injury treated within 24 hours of onset of symptoms, seen at an ED, by a specialist, or hospitalized, and results in > 7 day activity restriction.

  29. Injury Incidence Percent Injured

  30. Relation of Team Sport Participation to Injury Risk - Males

  31. Relation of Team Sport Participation to Injury Risk - Females

  32. Sample Size & Low Back Pain Incidence Incidence of LBP (%) Sample Size

  33. Case-Crossover Studies

  34. Conclusions • Descriptive studies are the most common approaches used today in injury research • Analytic designs are often difficult to conduct, but the yield in terms of new information can be great.

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