Whatareimportantprognosticfactors?"Answerstosuchquestionsprovidethe basisforbetterpreventionandtreatmentofdiseases. Many people contributed to the writing of this book: medical students in Denmark, studentsofepidemiologyattheIEAEEPEsummercourseinFlorence, Italy, andstudentsofpublichealthinLosAngeles. Withouttechnicalassistance v vi Preface fromGitteNielsen, JenadeShelley, NinaHoheandPamMasangkaythebookwould neverhavematerialized. LosAngeles, California JornOlsen Odense, Denmark KaareChristensen IowaCity, Iowa JeffMurray Stockholm, Sweden AndersEkbom Contents Part I Descriptive Epidemiology 1 Measures of Disease Occurrence . . . . . . . . . . . . . . . . . . . 3 IncidenceandPrevalence . . . . . . . . . . . . . . . . . . . . . . . . 4 Incidence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 RatesandDynamicPopulations . . . . . . . . . . . . . . . . . . . . . 7 CalculatingObservationTime. . . . . . . . . . . . . . . . . . . . . . 9 Prevalence, Incidence, Duration . . . . . . . . . . . . . . . . . . . . . 10 MortalityandLifeExpectancy . . . . . . . . . . . . . . . . . . . . . 11 LifeExpectancy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2 Estimates of Associations . . . . . . . . . . . . . . . . . . . . . . . 15 3 Age Standardization. . . . . . . . . . . . . . . . . . . . . . . . . . 19 4 Causes of Diseases . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5 Descriptive Epidemiology in Public Health. . . . . . . . . . . . . . 29 GraphicalModelsofCausalLinks . . . . . . . . . . . . . . . . . . . 33 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 6 Descriptive Epidemiology in Genetic Epidemiology. . . . . . . . . 37 OccurrenceDatainGeneticEpidemiology . . . . . . . . . . . . . . . 37 ClusteringofTraitsandDiseasesinFamilies . . . . . . . . . . . . . . 38 TheOccurrenceofGeneticDiseases . . . . . . . . . . . . . . . . . . 40 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 7 Descriptive Epidemiology in Clinical Epidemiology. . . . . . . . . 43 SuddenInfantDeathSyndrome(SIDS). . . . . . . . . . . . . . . . . 44 CytologicalScreeningforCervixCancer . . . . . . . . . . . . . . . . 45 ChangesinTreatmentofJuvenileDiabetes . . . . . . . . . . . . . . . 46 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 vii viii Contents Part II Analytical Epidemiology 8 Design Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 CommonDesignsUsedtoEstimateAssociations. . . . . . . . . . . . 51 EcologicalStudy . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Case-ControlStudy. . . . . . . . . . . . . . . . . . . . . . . . . . 54 CohortStudy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 ExperimentalStudy . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 9 Follow-Up Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 TheNon-experimentalFollow-Up(Cohort)Study . . . . . . . . . . . 59 StudyingRiskasaFunctionofBMI . . . . . . . . . . . . . . . . . . 60 LongitudinalExposureData. . . . . . . . . . . . . . . . . . . . . . . 62 DifferentTypesofCohortorFollow-UpStudies. . . . . . . . . . . . 63 10 Case-Control Studies. . . . . . . . . . . . . . . . . . . . . . . . . . 67 Case-CohortSampling . . . . . . . . . . . . . . . . . . . . . . . . . 69 DensitySamplingofControls. . . . . . . . . . . . . . . . . . . . . . 69 Case-Non-caseStudy. . . . . . . . . . . . . . . . . . . . . . . . . . 71 PatientControls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 SecondaryIdenti cationoftheSourcePopulation . . . . . . . . . . . 74 Case-ControlStudiesUsingPrevalentCases. . . . . . . . . . . . . . 74 WhentoDoaCase-ControlStudy? . . . . . . . . . . . . . . . . . . . 77 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 11 The Cross-Sectional Study. . . . . . . . . . . . . . . . . . . . . . . 79 12 The Randomized Controlled Trial (RCT) . . . . . . . . . . . . . . 81 Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . | An Introduction to Epidemiology for Health Professionals by Jorn Olsen, Paperback | Indigo Chapters