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Introduction to Epidemiology

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Presentation on theme: "Introduction to Epidemiology"— Presentation transcript:

1 Introduction to Epidemiology
Manish Chaudhary

2 Basic Concept in Epidemiology
Epidemiology is the study of the occurrence, distribution and determinants of health problems and diseases in human population or communities and the use of this knowledge for prevention and control of diseases. The primary unit of concern is a group of person not any single person. Therefore epidemiology deals with population pathology not the clinical pathology.

3 Word “Epidemiology” is derived from Greek words:
Epi= upon , on Demos= people Logus= study, knowledge Thus epidemiology in its broadest sense is the study of effects of various things on people.

4 The evolutions of Definitions of Epidemiology
Historical definition “The science and doctorine of epidemics”( New standard dictionary of English Language) The science of epidemics and epidemic disease.( stedmans practical medical dictionary) The science of mass phenomena of infectious disease or the natural history of infectious diseases ( Frost, 1927) The science of infective diseases, their prime causes, propagation and prevention(Stallybrass, 1931) Study of disease, any disease, as a mass phenomena-(Greenwood 1932)

5 Modern Meaning Epidemiology is the science which concerns itself with the natural history of disease as it is expressed in groups of persons related by some common factors of age, sex, race, location or occupation as distinct from the development of disease in an individual.( American Epidemiological Society) Epidemiology is the study of the pattern of diseases and the factors that cause disease in man( CDC, US Public health services) “The study of the frequency, distribution and determinants of disease in human population" - Mac Mohan and Pugh

6 A widely accepted definition is “the study of distribution and determinants of health related states and events in specified populations, and the application of this study to control of health problems"-Last, 1988

7 Three important components included in these definitions are:
Frequency Distribution Determinants

8 The first component to be considered is measurement of disease frequency, which involves quantification of the occurrence of disease. The second component is distribution of disease in terms of time, place, and person- who is getting the disease, where and when the disease is occurring. The third component, the determinant of disease derives from the first two, since knowledge of frequency and distribution of disease is necessary to test an epidemiological hypothesis.

9 Aims of epidemiology To describe the distribution and size of disease problems in human populations. (Descriptive epidemiology) To identify the etiological factors in the pathogenesis of disease (Analytical epidemiology) To provide the data essential in planning, implementation and evaluation of services for the prevention, control and treatment of disease and setting up priorities among those services. (Experimental epidemiology)

10 The ultimate aim of epidemiology is
to eliminate or reduce the health problem or its consequences to improve medical care and provide administrative guidance for community health services to promote the health and well being of society as a whole

11 Functions/Uses of epidemiology
To find causation of the disease To describe natural history Description of health status of populations Evaluation of intervention Community diagnosis Planning and evaluation Investigate epidemics of unknown etiology Elucidate mechanism of disease transmission

12 Scope of epidemiology Disease definition: characteristics or combination of character that best discriminate disease from non diseased Disease occurrence: the rate of development of new case in population. The proportion of current disease within population Disease causation: the risk factors for disease development and their relative strength with respect to an individual and population Disease outcome: the outcome following disease onset and of the risk factors. Disease management: the relative effectiveness of proposed therapeutic interventions Disease prevention: the relative effectiveness of proposed preventive strategies including screening

13 Comparison between Epidemiology and Clinical Medicine
Subjects Epidemiology Clinical Medicine Unit of study Defined population or population at risk Case or cases Examination Survey of particular community patients Concern with Both sick and healthy people Cases with disease pattern Diagnosis People/ community diagnosis Patients diagnosis with the help of signs and symptoms Objective To identify particular source of infection, mode of transmission, aetiological factors, ways of controlling these problems and continuous follow up To diagnose, prognosis and prescribe specific treatment for the diseases within limited period of time Relationship Epidemiological team goes to community to find and solve health problem Patient come to the doctor for treatment Area concern Concern with preventive and promotive measure Concern with curative measure Concept Biostatistical Biomedical Result Symbolized in the form of tables and graphs Symbolized as medical and laboratory report Time Sustainable and long process Quick and short result

14 Thank You

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