© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Vit-Mar/Shutterstock© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER 2 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FORPractical SALE OR DISTRIBUTION ApplicationsNOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning,of Epidemiology LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION LEARNING OBJECTIVES © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC By the end of this chapter the reader will be able to: NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ■ contrast the seven uses of epidemiology ■ explain how population dynamics influence community health ■ differentiate between uses of epidemiology for health services and disease etiology ■ relate epidemiologic methods to specific clinical applications © Jones & Bartlett■ compare Learning, epidemiologic LLC models of causality © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER OUTLINE © Jones & Bartlett Learning,Introduction LLC © JonesApplications & Bartlett Relevant Learning, to Disease Etiology LLC NOT FOR SALE OR DISTRIBUTIONWhat Are the Key Uses of Epidemiology? NOT FORConclusion SALE OR DISTRIBUTION Applications for the Assessment of the Health Study Questions and Exercises Status of Populations and Delivery of Health References Services © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION KEY TERMS Demographic transition Health disparities Secondary prevention Dynamic population Population dynamics Tertiary prevention © Jones & EpidemiologicBartlett Learning, transition LLCPrimary prevention © Jones & Bartlett Learning, LLC NOT FOR SALEFixed population OR DISTRIBUTIONPrimordial prevention NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning,© Jones LLC & Bartlett Learning LLC, an Ascend Learning© Jones Company. & NOT Bartlett FOR SALE Learning, OR DISTRIBUTION. LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 9781284191127_CH02_Friis.indd 49 20/02/20 8:56 PM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 50 Chapter 2 Practical Applications of Epidemiology ▸ Introduction© Jones & Bartlett Learning,▸ LLCWhat Are the Key© Uses Jones & Bartlett Learning, LLC In two majorNOT sections, FOR this SALE chapter OR provides DISTRIBUTION of Epidemiology?NOT FOR SALE OR DISTRIBUTION a broad overview of the uses of epidemiology in support of public health practice. You will JN Morris encapsulated the uses of epidemi- see how epidemiology provides a method- ology in his brilliant and classic 1975 work ological toolkit for implementation in public titled Uses of Epidemiology.1 This book has © Joneshealth &practice Bartlett and health Learning, sciences LLCmore gen- withstood the test© Jones of time and& Bartlett remains releLearning,- LLC NOTerally. FOR The SALE first ORsection DISTRIBUTION covers applications vant today: MorrisNOT argued FOR that SALE the uses OR could DISTRIBUTION of epidemiology in health status and health be summarized under seven categories, which services. For example, you will discover how remain current in contemporary epidemiol- epidemiology helps public health practi- ogy. (See FIGURE 2-2 and EXHIBIT 2-1 for the tioners and administrators plan for alloca- seven uses of epidemiology.) © Jones & Bartletttion Learning, of resources. LLC Also, you will gain insight © JonesEpidemiologic & Bartlett research Learning, leads to LLCobtain- NOT FOR SALE ORinto DISTRIBUTIONhow epidemiology helps to evaluate NOTing knowledgeFOR SALE that may OR be DISTRIBUTION helpful in efforts to services that have been implemented. The prevent disease and elicits the attention of the second part concerns the uses of epidemiol- popular media. Results of epidemiologic stud- ogy in exploring disease causality, which in ies are often quite newsworthy and sometimes controversial. More and more frequently, medi- many instances© Jones (e.g., some & Bartlett forms of cancer)Learning, LLC © Jones & Bartlett Learning, LLC remains unknown. (See FIGURE 2-1.) You will cal journals such as the New England Journal of find out howNOT epidemiologists FOR SALE in a OR variety DISTRIBUTION of Medicine (NEJM) are publishing reportsNOT ofFOR epi- SALE OR DISTRIBUTION settings (research universities, federal agen- demiologic studies.2 These studies proliferate for cies, private organizations, and elsewhere) a number of key reasons. First, they concentrate continue their quest for clues as to the nature on associations between diseases and possible lifestyle factors, such as a habit, type of behavior, © Jonesof disease. & Bartlett You will Learning,acquire insights LLC into the © Jones & Bartlett Learning, LLC strengths and limitations of applying epide- or some element of the diet, that presumably can NOTmiologic FOR SALE methods OR to theDISTRIBUTION search for causes of be changed. Consequently,NOT FOR “The SALE reports OR are . DISTRIBUTION. disease. Finally, you will learn about some of often of great interest to the popular media and the applications of epidemiology in clinical the public, as well as to physicians interested in decision-making. preventive medicine.”2(p823) A second reason is that the major diseases predominant in American © Jones & Bartlett Learning, LLC © societyJones are & “chronic, Bartlett degenerative Learning, diseases LLC that NOT FOR SALE OR DISTRIBUTION NOTprobably FOR have SALE several OR contributing DISTRIBUTION causes, some of which have to do with lifestyle, operating over long periods.”2(p823) An NEJM editorial noted, It is usually very difficult to investi- © Jones & Bartlett Learning, LLCgate such risk factors through© exper Jones- & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONimental (or interventional) NOTstudies. FOR SALE OR DISTRIBUTION In some cases it is impractical and in some it is unethical. For example, researchers cannot expose half of a group of children to lead for 10 years © Jones & Bartlett Learning, LLC to compare© theirJones IQs &20 Bartlettyears later Learning, LLC NOTFIGURE FOR 2-1 SALE Researching OR theDISTRIBUTION Causes of Diseases Is a with those NOTof the unexposedFOR SALE children. OR DISTRIBUTION Major Activity of Epidemiology We must therefore rely on epidemio- © Gorodenkoff/Shutterstock logic (or observational) studies.2(p823) © Jones & Bartlett Learning,© Jones LLC & Bartlett Learning LLC, an Ascend Learning© Jones Company. & NOT Bartlett FOR SALE Learning, OR DISTRIBUTION. LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 9781284191127_CH02_Friis.indd 50 20/02/20 8:56 PM © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION What Are the Key Uses of Epidemiology? 51 © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE ORSeven DISTRIBUTION uses of epidemiology NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTIONHealth status and NOT FOR SALE OR DISTRIBUTION Disease etiology health services © Jones & Bartlett Learning, LLCStudy Diagnose Examine the© JonesEstimate & BartlettIdentify CoLearning,mplete Search LLC for history of the health working of individual syndromes the clinical causes NOT FOR SALE OR DISTRIBUTIONthe health of the health NOTrisks FORand SALE OR pictuDISTRIBUTIONre of community services chances populations FIGURE 2-2 The Seven Uses of Epidemiology © DataJones from Morris JN. Uses& of EpidemiologyBartlett. 3rd ed. Edinburgh, Learning, UK: Churchill Livingstone;1975:262–263. LLC © 1975, with permission of Elsevier. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION EXHIBIT 2-1 Seven Uses of Epidemiology The epidemiological method is the only way of asking some questions in medicine, one way of asking © Jones & others,Bartlett and no Learning, way at all to ask LLC many. Several uses of epidemiology© Joneshave been & described: Bartlett Learning, LLC NOT FOR SALE1. To studyOR theDISTRIBUTION history of the health of populations, and of the NOTrise and FOR fall of diseases SALE and OR changes DISTRIBUTION in their character. Useful projections into the future may be possible. 2. To diagnose the health of the community and the condition of the people, to measure the true dimensions and distribution of ill-health in terms of incidence, prevalence, disability, and mortality; to set health problems in perspective and define their relative importance; to identify groups needing special attention. Ways of life change, and with them the community’s health; © Jones & Bartlett Learning,new LLC measurements for monitoring them© Jones must therefore & Bartlett constantly Learning,be sought. LLC NOT FOR SALE OR DISTRIBUTION3. To study the working of health services NOTwith a view FOR to their SALE improvement. OR DISTRIBUTION Operational research translates knowledge of (changing) community health and expectations in terms of needs for services and measure [sic] how these are met. The success of services delivered in reaching stated norms, and the effects on community health—and its needs—have to be appraised, in relation to resources. Such knowledge may be applied in action research pioneering better