1. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Chapter 7 Epidemiology in Community Health Care

2. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Historical Roots of Epidemiology Ancient Times: Hippocrates (460 to 375 BC) Middle Ages:1348 - Plague ( “ Black Death ” ) 18th century: Florence Nightingale (1820 – 1910) 19th century: Modern epidemiology (see Table 8-1) –Causal thinking –Sanitary statistics –Infectious-disease epidemiology –Chronic-disease epidemiology Current: Eco-epidemiology

3. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Host, Agent, and Environment Model Host –Susceptible human or animal who harbors and nourishes a disease-causing agent Agent –A factor that causes or contributes to a health problem or condition Environment –All the external factors surrounding the host that might influence vulnerability or resistance

4. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Theories of Causality in Health and Illness Relationship between a cause and its effect –Chain of causation –Causation in noninfectious disease: environmental exposure and potential health outcomes (9 elements) –Multiple causation Dever ’ s epidemiological model, also called the web of causation

5. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

7. Question Is the following statement true or false? The current thinking of epidemiology focuses on causal thinking.

8. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer False –Current thinking of epidemiology is termed eco- epidemiology and is distinguished by transforming global health patterns and technological advances.

9. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Immunity A host ’ s ability to resist a particular infectious disease-causing agent –Passive immunity: short-term; acquired naturally or artificially –Active immunity: long-term, sometimes lifelong; acquired naturally or artificially –Cross-immunity: immunity to one agent providing immunity to another related agent –Herd immunity: immunity level present in a population group

10. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Risk Probability that a disease or unfavorable health condition will develop Directly influenced by biology, environment, lifestyle, and system of health care. Risk factors: negative influences Epidemiologists studying populations at risk: collection of people among whom a health problem has the possibility of developing because certain influencing factors are present or absent or because there are modifiable risk factors Measurement of relative risk ratio: incidence rate in exposed group/incidence rate in unexposed group

11. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Natural History of a Disease or Health Condition Susceptibility stage Subclinical disease stage –Incubation period –Induction period Clinical disease stage Resolution stage

12. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins

13. Sources of Epidemiologic Information Vital statistics Census data Reportable diseases Disease registries Environmental monitoring National Center for Health Statistics health surveys Informal observational studies Scientific studies

14. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Question During which stage would the community health nurse first expect to see signs of a disease via laboratory testing? a.Susceptibility stage b.Subclinical disease stage c.Clinical disease stage d.Resolution stage

15. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer c. Clinical disease stage During the clinical disease stage, signs and symptoms develop, and in the early phase of this period they may be evident only through laboratory test findings. In the susceptibility stage, the disease is not present and individuals have not been exposed. During the subclinical disease stage, individuals have been exposed but are asymptomatic. During the resolution stage, the disease causes sufficient changes to produce recognizable signs and symptoms.

16. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Methods in Epidemiologic Investigative Process Descriptive epidemiology –Counts –Rates Incidence: refers to all new cases of a disease or health condition appearing during a given time Number of persons developing a disease Total number at risk per unit of time

17. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Methods in Epidemiologic Investigative Process (cont.) –Rates Prevalence: all of the people with a particular health condition existing in a given population at a given point in time Number of persons with a characteristic Total number in population –Computing rates Mortality Morbidity

18. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Methods in Epidemiologic Investigative Process (cont.) Analytic epidemiology –Prevalence studies –Case-control studies –Cohort studies Experimental epidemiology

19. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Research Process for an Epidemiologic Study 1. Identify the problem. 2. Review the literature. 3. Design the study. 4. Collect the data. 5. Analyze the findings. 6. Develop conclusions and applications. 7. Disseminate the findings.

20. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Question Is the following statement true or false? Analytic epidemiology involves cohort studies.

21. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Answer True –Analytic epidemiology attempts to identify associations between a human disease or health problem and its possible causes. Analytic studies include prevalence studies, case-control studies, and cohort studies.

22. Copyright © 2010 Wolters Kluwer Health | Lippincott Williams & Wilkins Internet Resources Association for Professionals in Infection Control and Epidemiology, Inc.: http://www.apic.orghttp://www.apic.org Centers for Disease Control and Prevention: http://www.cdc.gov http://www.cdc.gov Certification Board of Infection Control and Epidemiology, Inc.: http://www.cbic.orghttp://www.cbic.org Environmental Protection Agency: http://www.epa.gov http://www.epa.gov Immunization Action Coalition: http://www.immunize.org http://www.immunize.org National Center for Health Statistics: http://www.cdc.gov/nchs/fastats/Default.htm http://www.cdc.gov/nchs/fastats/Default.htm