Introduction to Epidemiology PDF

Introduction to Epidemiology Dr/ fatma Elswerky Assistant professor of family and community health nursing  The historical context Epidemiology originates from Hippocrates' observation more than 2000 years ago that Environmental factors influence the occurrence of disease. The fin...

Introduction to Epidemiology Dr/ fatma Elswerky Assistant professor of family and community health nursing  The historical context Epidemiology originates from Hippocrates' observation more than 2000 years ago that Environmental factors influence the occurrence of disease. The finding by John Snow that the risk of cholera in London was related to the drinking of water supplied by a particular company provides a well- known example  Comparing rates of disease in subgroups of the human population became common practice in the late 19th and early 20th centuries. This approach was initially applied to the control of communicable diseases, but proved to be a useful way of  In the second half of the 20th century, these methods were applied to chronic non- communicable diseases such as heart disease and cancer, especially in middle and high- income countries.  Recent developments in epidemiology Epidemiology in its modern form is a relatively new discipline and uses quantitative methods to study diseases in human populations, to inform prevention and control efforts. For example, Richard Doll and Andrew Hill studied the relationship between tobacco use and lung cancer, beginning in the 1950s. By using long-term cohort studies, Introduction to Epidemiology Dr. Samiha Hamdi  Outline  Definition  Components of epidemiology Disease frequency Distribution of disease Determinants of disease  Uses of epidemiology  Sources of epidemiological data Dr. Samiha Hamdi  Introduction Epidemiology is concerned with the study of causes and distribution of diseases and health problems which are essential for identification of preventive measures also it is concerned with the course and outcome of Dr. Samiha Hamdi It is a basic science for both public health and medicine. Upon People Scienc e Dr. Samiha Hamdi  Definition of epidemiology It is the study of the frequency, distribution and determinants of health related phenomena in human populations and the application of this study for prevention of disease and promotion of health Dr. Samiha Hamdi  Definition of epidemiology "The study of the distribution and determinants of health- related states or events in specified populations, and the application of this study to the prevention and control of health problems" Dr. Samiha Hamdi  Components of epidemiology 1) Frequency The number of time an event occurs. The basic measures of disease Itfrequency answersare the ratesquestion and ratio how (e.g. many? incidence rate, prevalence rate etc.,) Thus epidemiology is a Dr. Samiha Hamdi  p tiv ri Components of c Des e i ol epidemiology d e m of disease Epi gy o  Components of y ti ca l n a l i o l epidemiology A p i d e m 3) Determinants of disease E ogy It concerned with testing the etiological hypothesis and identifying the underlying causes or risk factors of diseases Dr. Samiha Hamdi Dr. Samiha Hamdi  Uses of epidemiology 1-Identification of the magnitude of the health problem through measures of disease frequency 2-Observation and description of the natural history of diseases 3-Help in definition and classification of diseases as viral hepatitis A, B…Dr. Samiha Hamdi  Uses of epidemiology 4- Identification of determinants of diseases through hypothesis testing studies 5- Provision of data necessary for planning and evaluation of health programs 6-Supply the essential data related to availability, accessibility and utilization of health services Dr. Samiha Hamdi  Sources of epidemiological data 1- Census it is the periodic counting of the population of a country. It include information about size, composition (age, sex, marital and socioeconomic status)and distribution of a population Dr. Samiha Hamdi  Sources of epidemiological data 2- Population estimates It is the size of population in inter-censal years. It can be estimated by using the preceding census as starting point and taking into account births, deaths, migration.  Population data is useful in:- - Planning health services - Computing morbidity and mortality rates  Sources of epidemiological data 3- Vital records  Birth registration: essential for computation of rates related to infancy and complications of pregnancy, delivery and puerperium  Death registration: registered after the seventh month of pregnancy and burial permission is only issued after registration  Sources of epidemiological data 4- Notification of infectious diseases Reporting of certain diseases to public health authorities is useful in:-  Indicating the fluctuation in disease occurrence  Providing data for planning and evaluating the  Sources of epidemiological data 5-Disease registers: For patients with diseases of public health concern as TB, cancer 6- Hospital records: It includes inpatients and outpatients records 7-Special subgroups records: for school children, insured workers and armed  Sources of epidemiological data 8- Morbidity survey: field studies of the frequency and distribution of specific diseases 9- Record linkage: the process by which medical records from two or more different sources are brought together to provide single file for individual