Epidemiology including health structure and scientific study

epidemiology

1. Epidemiology An Introduction to the Study of Health and Disease in Populations

2. Definition Epidemiology is the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to control health problems.

3. History of Epidemiology • Hippocrates – First to relate environment to disease • John Graunt – Mortality statistics • William Farr – Vital statistics system • John Snow – Father of modern epidemiology

4. Aims of Epidemiology 1. Describe health status of populations 2. Identify causes of diseases 3. Predict future disease occurrence 4. Control and prevent disease distribution

5. Core Concepts • Distribution (time, place, person) • Determinants (causes, risk factors) • Population focus • Application in public health

6. Epidemiological Triad Model for infectious disease causation: • Agent • Host • Environment

7. Types of Epidemiology 1. Descriptive 2. Analytical 3. Experimental

8. Descriptive Epidemiology Focuses on 'What, Who, When, Where' • Case reports • Case series • Surveillance • Population surveys

9. Analytical Epidemiology Focuses on 'Why and How' Study designs: • Case-control studies • Cohort studies • Cross-sectional studies

10. Experimental Epidemiology Involves intervention by the researcher: • Clinical trials • Field trials • Community trials

11. Measures of Disease Frequency • Incidence • Prevalence • Attack rate • Mortality rate

12. Measures of Association • Risk ratio (Relative risk) • Odds ratio • Attributable risk

13. Screening in Epidemiology Early detection of disease: • Sensitivity • Specificity • Predictive values

14. Uses of Epidemiology • Study natural history of disease • Identify determinants • Evaluate health services • Provide evidence for policy • Guide public health practice

15. Steps in an Epidemiological Investigation 1. Define the problem 2. Describe by time, place, person 3. Develop hypotheses 4. Test hypotheses 5. Recommend control measures

16. Applications in Public Health • Outbreak investigation • Program evaluation • Health planning • Risk assessment

17. Challenges in Epidemiology • Bias • Confounding • Ethical issues • Emerging diseases • Global health concerns

18. Conclusion Epidemiology provides the scientific basis for public health action, guiding disease prevention, health promotion, and policy-making.