Chapter 7 Epidemiology in Community Health Care

1. Chapter 7Epidemiology in Community Health Care

2. 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. 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. 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

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

8. Answer • False • Current thinking of epidemiology is termed eco-epidemiology and is distinguished by transforming global health patterns and technological advances.

9. 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. 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. Natural History of a Disease or Health Condition • Susceptibility stage • Subclinical disease stage • Incubation period • Induction period • Clinical disease stage • Resolution stage

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. Question During which stage would the community health nurse first expect to see signs of a disease via laboratory testing? • Susceptibility stage • Subclinical disease stage • Clinical disease stage • Resolution stage

15. 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. 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 diseaseTotal number at risk per unit of time

17. 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. Methods in Epidemiologic Investigative Process (cont.) • Analytic epidemiology • Prevalence studies • Case-control studies • Cohort studies • Experimental epidemiology

19. 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. Question Is the following statement true or false? • Analytic epidemiology involves cohort studies.

21. 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. Internet Resources • Association for Professionals in Infection Control and Epidemiology, Inc.: http://www.apic.org • Centers for Disease Control and Prevention: http://www.cdc.gov • Certification Board of Infection Control and Epidemiology, Inc.: http://www.cbic.org • Environmental Protection Agency: http://www.epa.gov • Immunization Action Coalition: http://www.immunize.org • National Center for Health Statistics: http://www.cdc.gov/nchs/fastats/Default.htm