Course SS1978 u
Principles of Epidemiology u u
in Public Health Practice
u u u
Third Edition u
An Introduction
u
to Applied Epidemiology and Biostatistics
u u u u
Octoberu2006
UpdateduMayu2012
U.S.uDEPARTMENTuOFuHEALTHuANDuHUMANuSERVICES
CentersuforuDiseaseuControluanduPreventionu(CD
C)uOfficeuofuWorkforceuanduCareeruDevelopmentu
Atlanta,uGAu30333
,CONTENTS
Acknowledgments ................................................................................................................v
Introduction ...................................................................................................................... viii
Lesson One: Introduction to Epidemiology
u u u u
LessonuIntroduction .......................................................................................................... 1-1
LessonuObjectives............................................................................................................. 1-1
MajoruSections
DefinitionuofuEpidemiology ........................................................................................ 1-2
HistoricaluEvolutionuofuEpidemiology ........................................................................ 1-7
Uses .......................................................................................................................... 1-12
CoreuEpidemiologicuFunctions ................................................................................. 1-15
TheuEpidemiologicuApproach ................................................................................... 1-21
DescriptiveuEpidemiology ........................................................................................ 1-31
AnalyticuEpidemiology ............................................................................................. 1-46
ConceptsuofuDiseaseuOccurrence .............................................................................. 1-52
NaturaluHistoryuanduSpectrumuofuDisease ................................................................. 1-59
ChainuofuInfection ..................................................................................................... 1-62
EpidemicuDiseaseuOccurrence .................................................................................. 1-72
Summary .................................................................................................................. 1-80
ExerciseuAnswers ........................................................................................................... 1-81
Self-AssessmentuQuiz..................................................................................................... 1-85
AnswersutouSelf-AssessmentuQuiz .................................................................................. 1-90
References ...................................................................................................................... 1-93
Lesson Two: Summarizing Data
u u u
LessonuIntroduction .......................................................................................................... 2-1
LessonuObjectives............................................................................................................. 2-1
MajoruSections
OrganizinguData.......................................................................................................... 2-2
TypesuofuVariables ...................................................................................................... 2-4
FrequencyuDistributions ............................................................................................. 2-7
PropertiesuofuFrequencyuDistributions ...................................................................... 2-11
MethodsuforuSummarizinguData ................................................................................ 2-15
MeasuresuofuCentraluLocation ................................................................................... 2-16
MeasuresuofuSpread .................................................................................................. 2-36
ChoosingutheuRightuMeasureuofuCentraluLocationuanduSpread .................................. 2-53
Summary .................................................................................................................. 2-58
ExerciseuAnswers ........................................................................................................... 2-59
Self-AssessmentuQuiz..................................................................................................... 2-64
AnswersutouSelf-AssessmentuQuiz .................................................................................. 2-69
References ...................................................................................................................... 2-71
Lesson Three: Measures of Risk
u u u u
Introduction
Pageuii
,LessonuIntroduction .......................................................................................................... 3-1
LessonuObjectives............................................................................................................. 3-1
MajoruSections
FrequencyuMeasures ................................................................................................... 3-2
MorbidityuFrequencyuMeasures ................................................................................ 3-10
MortalityuFrequencyuMeasures ................................................................................. 3-20
Natalityu(Birth)uMeasures ......................................................................................... 3-38
MeasuresuofuAssociation ........................................................................................... 3-39
MeasuresuofuPublicuHealthuImpact ............................................................................ 3-48
Summary .................................................................................................................. 3-51
ExerciseuAnswers ........................................................................................................... 3-52
Self-AssessmentuQuiz..................................................................................................... 3-56
AnswersutouSelf-AssessmentuQuiz .................................................................................. 3-62
References ...................................................................................................................... 3-65
Lesson Four: Displaying Public Health Data
u u u u u
LessonuIntroduction .......................................................................................................... 4-1
LessonuObjectives............................................................................................................. 4-1
MajoruSections
IntroductionutouTablesuanduGraphs.............................................................................. 4-2
Tables ......................................................................................................................... 4-3
Graphs ...................................................................................................................... 4-22
OtheruDatauDisplays.................................................................................................. 4-42
UsinguComputeruTechnology.................................................................................... 4-63
Summary .................................................................................................................. 4-66
ExerciseuAnswers ........................................................................................................... 4-72
Self-AssessmentuQuiz..................................................................................................... 4-79
AnswersutouSelf-AssessmentuQuiz .................................................................................. 4-84
References ...................................................................................................................... 4-87
Lesson Five: Public Health Surveillance
u u u u
LessonuIntroduction .......................................................................................................... 5-1
LessonuObjectives............................................................................................................. 5-1
Majoru u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u u Sections:u u Introduction . 5-2
PurposeuanduCharacteristicsuofuPublicuHealthuSurveillance ........................................ 5-4
IdentifyinguHealthuProblemsuforuSurveillance............................................................. 5-6
IdentifyinguoruCollectinguDatauforuSurveillance ........................................................ 5-13
AnalyzinguanduInterpretinguData............................................................................... 5-23
DisseminatinguDatauanduInterpretations .................................................................... 5-34
EvaluatinguanduImprovinguSurveillance.................................................................... 5-38
Summary .................................................................................................................. 5-42
AppendixuA. CharacteristicsuofuWell-ConducteduSurveillance .............................. 5-43
AppendixuB. CDCuFactuSheetuonuChlamydia ......................................................... 5-45
AppendixuC. ExamplesuofuSurveillance ................................................................. 5-48
Introduction
Pageuiii
, AppendixuD. MajoruHealthuDatauSystemsuinutheuUniteduStates .............................. 5-52
AppendixuE. LimitationsuofuNotifiableuDiseaseuSurveillanceuand
RecommendationsuforuImprovement ................................................ 5-53
ExerciseuAnswers ........................................................................................................... 5-57
Self-AssessmentuQuiz..................................................................................................... 5-63
AnswersutouSelf-AssessmentuQuiz .................................................................................. 5-68
References ...................................................................................................................... 5-73
Lesson Six: Investigating an Outbreak
u u u u
LessonuIntroduction .......................................................................................................... 6-1
LessonuObjectives............................................................................................................. 6-1
MajoruSections:
IntroductionutouInvestigatinguanuOutbreak .................................................................. 6-2
StepsuofuanuOutbreakuInvestigation ............................................................................. 6-8
Summary .................................................................................................................. 6-57
ExerciseuAnswers ........................................................................................................... 6-59
Self-AssessmentuQuiz..................................................................................................... 6-64
AnswersutouSelf-AssessmentuQuiz .................................................................................. 6-71
References ...................................................................................................................... 6-75
Glossary
Introduction
Pageuiv