1 Intro to Epidemiology.pptx epidemiology
- 1. INTRODUCTION TO EPIDEMIOLOGY YIMER.S (BSC, MPH epi and Bio) 2017 1
- 2. Outline • Definition of Epidemiology • History of Epidemiology • Scope of Epidemiology • Uses of Epidemiology • Fundamental Assumptions in Epidemiology 2
- 3. Objectives At the end of this lesson, learners will be able to: – Define Epidemiology and its components – Distinguish between descriptive and analytic Epidemiology – Understand history and scope of Epidemiology – Describe the basic assumption and uses of Epidemiology 3
- 4. Introduction to Epidemiology • Epidemiology – defined in so many ways! • Epidemiology is the basic science of public health • All the definitions are similar – They focus on: • Health promotion • Disease prevention 4
- 5. What is public health? 5 • The science and art of preventing disease, prolonging life and promoting physical and mental health and efficiency through organized efforts and informed choices of society, organizations, public and private, communities and individuals”.
- 6. • Epidemiology is: – A quantitative basic science – A method of causal reasoning – A tool of public health action 6
- 7. • Public health differs from clinical medicine: – Emphasis on prevention rather than treatment – Focus on populations rather than individuals 7
- 8. Epidemiology • Definition – Epidemiology is the study of frequency, distribution and determinants of disease and health related problems, and its application to disease prevention and health promotion in a specified population – There are a lot of important terms here: study, frequency, distribution, determinant, health related problem, specified population 8
- 9. • Study – Epidemiology is a scientific discipline – It has sound methods of scientific investigation at its foundation – Also called the basic science of public health 9
- 10. • Frequency – It indicates the quantitative aspect of Epidemiology – Related to the number of health related events – Also the rate or risk of disease – Can be split into morbidity and mortality rates 10
- 11. • Distribution – Related to the pattern of health events – Occurrence of health events by time, place and personal characteristics – Time (annual, seasonal, hourly occurrences) – Place (geography, urban-rural variation) – Personal (age, sex, race) 11
- 12. • Determinants – Causes, etiology, predisposing factors, precipitating factors, etc. – The domain of Analytic Epidemiology – The response for how and why questions 12
- 13. • Health related problems • Specified populations How do clinicians and epidemiologists view a patient? 13
- 14. • Application – Epidemiology is more than just ‘the study of’. – It provides data for directing public health action – It is an art as well as a science 14
- 15. • Sometimes Epidemiology is described by the type of studies it is composed of • The key features of epidemiological studies – Quantitative rather than qualitative – Observational rather than experimental – Population based rather than individuals 15
- 16. • Epidemiology has two major branches: – Descriptive Epidemiology • What • Who • When • Where – Analytic Epidemiology • How • Why 16
- 17. • Examples of Analytic Epidemiology – Studying the effects of factors on disease occurrence – Studying the etiology of a particular disease – Verifying the efficacy of a particular vaccine trial 17
- 18. History of Epidemiology • Epidemiology originated from Hippocrates’ observation more than two millennia ago. – Environmental and host factors influence disease occurrence – Disease occurrence was explained from a rational instead of a supernatural viewpoint 18
- 19. • Mortality data analysis was tried in Britain in the 17th century • In the 19th century – An extensive work on mortality data analysis – Measurement of disease conditions in specified human populations – Marked the formal beginnings of Epidemiology – Heralded many fantastic epidemiologic achievements 19
- 20. • John Snow – Assessed cholera epidemic in London in the mid-19th century(1854) – This assessment is an important epidemiologic milestone in history – It earned him the title ‘the father of field epidemiology’ 20
- 21. • Late 19th century and early 20th century – Comparison of disease rates in subgroups of populations became popular – An important tool of linking environmental factors with specific diseases • 2nd half of 20th century – Comparison of disease rates advanced to non communicable chronic diseases 21
- 22. • Epidemiology in recent years – A quantitative science – Focuses on prevention and control of diseases – The association between cigarette smoking and lung cancer is a recent Epidemiologic achievement • Done using long term epidemiological cohort studies – Small pox eradication in the 1960s and 1970s 22
- 23. • Communicable disease epidemiology has become a vital discipline because of – HIV/AIDS – Tuberculosis – Malaria 23
- 24. Scope of Epidemiology • A number of transitions have been seen in the history of Epidemiology: – Epidemiology was initially linked to the study of epidemic diseases mostly of communicable nature – Later on other diseases of non communicable nature were included in the scope – At present epidemiologic methods are being applied to: • Injuries and accidents Nutritional deficiencies • Mental disorders MCH • Congenital anomalies Cancer • Occupational health Environmental health • Health behaviours 24
- 25. Uses of Epidemiology • Epidemiology has a big list of uses some of which are: – Monitoring the public health – Studying the natural history of diseases – Looking for causes of disease, death and disability – etiological agents – Evaluating interventions and health service provision – Planning health services – Decision making in clinical medicine 25
- 26. Fundamental Assumptions in Epidemiology • Human diseases do not occur at random! • Human diseases have causal and preventive factors that can be identified through systematic investigations! 26
- 27. Assignment 27 – Q1. Who are some of the scientists who shaped epidemiologic thought? Discuss their contribution – Q2. Discuss How John Snow Assessed cholera epidemic in London in the mid-19th century(1854) – Q3. Discuss the special fields of epidemiology and their scope?
- 28. 28 THANK YOU