Notescourse‘IntroductionDescriptive
EpidemiologyandPublicHealth’
(HNH-28303)
Content
Notesweek1 2
1.1Introductiontoepidemiologyandpublichealth 2
1.2Historyofepidemiologyandpublichealth 4
1.3Descriptiveandanalyticalepidemiology 6
1.4Measuresofdiseaseoccurrence/frequency 6
1.5Diabetesprevalence 12
1.6Self-test 14
Summaryofthemoderator 16
Learninggoalsweek1: 17
Notesweek2 20
2.1Standardization 20
2.2Mortalityandmorbidity 28
2.3Assignment‘cancer’ 30
2.4Epidemiology,publichealthandprevention 32
2.5Studydesignsindescriptiveepidemiology 33
2.6Healthinelderlypeople 35
2.7Self-test 38
Summaryofthemoderator 40
Learninggoalsweek2: 41
Notesweek3 42
3.1Lifeexpectancy(LE)andCVD 42
3.2DFLE,DALEandHALE 48
3.3Disability-adjustedlifeyears(DALYs)andQuality-adjustedlifeyears(QALY) 50
3.4Globalburdenofdiseaseandinfectiousdiseases 54
3.5Self-test 60
Summaryofthemoderator 61
Learninggoalsweek3: 61
AppendixI-Assignment1.4g 62
AppendixII-Assignment3.3d 64
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IntroductionDescriptiveEpidemiologyandPublicHealth(HNH-28303)
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Note:Allreadingchaptersinthissummaryarederivedfrom:
WebbC.&BainP.(2017).Essentialepidemiology:anintroductionforstudentsandhealth
professionals.CambridgeUniversityPress,3rdor4thedition;andHaveman-Nies,A.,
Jansen,S.,vanOers,H.,&van'tVeer,P.(Eds.)(2017).Epidemiologyinpublichealth
practice.WageningenAcademicPublishers.Otherinformationisderivedfromthe
WageningenUniversityandResearch(WUR).
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Notesweek1
1.1Introductiontoepidemiologyandpublichealth
1.1aWhatisepidemiologyabout
Epidemiologyisas tudyofup/uponpeople.Thisfocusesonthequestion:whatarethe
distributionanddeterminantsofhealthrelatedstatesandeventsofpopulations(regarding
healthproblems)?Amorerecentdefinitionis:epidemiologyisaboutmeasuringhealth,
identifyingthecausesofill-health,andinterveningtoimprovehealth.Thisisdoneby
systematicallydiscoveringpatternsinalargeamountofinformation.Afterthat,youanalyse
thedatatounderstandthepatternsinordertoprevent/intervenedisease.Ane pidemicis
aboutthen ewcasesofadiseaseinagivenpopulationduringagiventimeperiodoccurata
ratethatsubstantiallye xceedswhatis‘’expected’’(basedonrecentexperience).A
pandemicisanepidemicthatspreadsacrossalargeregion,forexampleacontinentor
evenworldwide.Ane ndemic(infectious)diseaseiscommonataspecificplace(like
malaria).
1.1bEpidemiology:anacademicandappliedscience
Differentwaysofusingepidemiology.Thec liniciantranslatesthescientificknowledgeand
proceduresto:‘whatistheb esttreatmentforthiss pecificpatient?’.Thee
pidemiologistin
academicsettingthinksaboutthequestion:‘howcanIbesureaboutthisspecific
exposure-effect,independentofthecontextofthispersonorpopulation?’.Andthe
epidemiologistinpublichealthsettingthinksabout:‘thebestpreventionstrategyforthis
specificp opulation/riskgroup’.Thedifferencebetweenthelasttwoisthattheacademic
settingtriestoe
liminateotherfactors,contextandvalues,whilstthepublichealthsetting
triestoincorporateallthesefactors.
Scientificdetective Crimeprevention
Epidemiologistina
cademicsetting Epidemiologistinp
ublichealthsetting
Epidemiologyisabouta
nalysingpatterns Epidemiologyisaboutusingthis
andcauses informationforp
reventioninpopulations
A‘detective’aimstoanalyzeand Preventionthroughpolicies,programs,and
understandthesepatterns(who?where? interventions
when?why?what?)
Focusonknowledgeg
eneration Focusonknowledgea
pplication
Important: Important:
● Validity,precision,causation ● Generalizability,importance
● Relevanttomankind,anytime, ● Bestpractice
anyplace ● Relevanttome,hereandnow
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Thechainof‘food→health’isdescribedbelow,togetherwiththeplacewherepublichealth
andacademicepidemiologyispositioned.Thecyclecanalsobeexplainedbytheword
DISH.Theleftsideofthechainismostlyaboutthes
ocialfactorandtherightsideofthe
chainismostlyaboutthem edicalpart.
Source:WUR
1.1cEssentialepidemiology
Epidemiology,therefore,isaboutmeasuringhealth,identifyingthecausesofill-healthand
interveningtoimprovehealth.
Forexample,156outof343peoplewhoatehotchickenbecameilland156÷343=0.45
=45%.So45%ofpeoplewhoatehotchickenbecamesick.Thisisknownasthea ttack
rateforhotchicken,i.e.45%ofhot-chickeneaterswere‘attacked’byfoodpoisoning.
Forexample,45%ofpeoplewhoatehotchickenbecameill,comparedwith32%of
peoplewhodidnoteathotchicken.Hot-chickeneatersweretherefore1.4times(45%÷
32%=1.4)morelikelytobecomeillthanpeoplewhodidnoteathotchicken.This
measuregivesustheriskofsicknessinhotchickeneatersrelativetonon-eaters,henceits
name–relativerisk.
Descriptiveepidemiologyfocuseson‘person,placeandtime’.A nalyticstudieslookfor
associationsbetweenpotentialcausalagentsanddiseases.Epidemiologistsalsoe valuate
newpreventivemeasures,programsortreatmentsthataredesignedtoreduceillhealthor
promotegoodhealth.Theymonitortheeffectivenessofthese‘intervention’programsafter
theyhavebeenimplemented.
Inconclusion:
Againwehaveavividpictureofamasterepidemiologistatwork.Notsatisfiedthathis
hypothesishadbeenadequatelytested,Snowidentifiedtheopportunitytoconductaneven
morerigoroustest–his‘GrandExperiment’–andindoingsoheaddressedthemajor
epidemiologicalissuesthatstillconcernustoday.
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IntroductionDescriptiveEpidemiologyandPublicHealth(HNH-28303)