北美精算師協(xié)會SOA-美國的“帶病長壽”研究 Unhealthy Longevity in the United States 2023

UnhealthyLongevityintheUnitedStates

AUGUST|2023

UnhealthyLongevityintheUnitedStates

AStudyofMortalitybyHealthStatus

AUTHORSNataliaS.Gavrilova,Ph.D.

SeniorResearchAssociate

NORCattheUniversityofChicago

nsgavril@

SPONSORSMortalityandLongevityStrategic

ResearchProgramSteeringCommittee

LeonidA.Gavrilov,Ph.D.SeniorResearchScientist

NORCattheUniversityofChicago

lagavril@

CaveatandDisclaimer

TheopinionsexpressedandconclusionsreachedbytheauthorsaretheirownanddonotrepresentanyofficialpositionoropinionoftheSocietyof

ActuariesResearchInstitute,SocietyofActuaries,oritsmembers.TheSocietyofActuariesResearchInstitutemakesnorepresentationorwarrantytotheaccuracyoftheinformation.

Copyright?2023bytheSocietyofActuariesResearchInstitute.Allrightsreserved.

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CONTENTS

Introduction 5

ExecutiveSummary 5

KeyTakeaways 5

AnalysisofKeyTakeaways 6

OtherAnalysisHighlights 7

Section1:DefinitionofHealthyandUnhealthyStatus 8

Section2:TheSourceofInformationonPopulationHealth 9

Section3:ConstructionofPeriodLifeTables 10

3.1LifeTableConstructionforHealthyandUnhealthyIndividuals 11

3.2ComparisonofAge-SpecificDeathRatesbyHealthStatus 12

Section4:MortalityandLifeExpectancyofHealthyandUnhealthySubgroupsoftheU.S.Population 14

4.1GeneralDefinitionsofHealth:Self-RatedHealthandFrailtyIndex 14

4.2SpecificDefinitionsofHealth:MentalConditions,DisabilityandChronicDiseases 16

4.3LifeExpectancyin2010-2014and2015-2018byHealthStatus 23

Section5:MultimorbidityandMortality 26

Section6:PrevalenceofUnhealthyStatusbyRaceandRegion 28

6.1PrevalenceofUnhealthyStatusbyRace 28

6.2PrevalenceofUnhealthyStatusbyRegion 32

Section7:HealthStatusandCausesofDeath 37

7.1MortalitybyCausesofDeath 37

7.2ContributionofCVDandCancertoDifferencesinLifeExpectancy 40

Section8:PrevalencebyHealthStatusduringtheCOVID-19PandemicYears 42

8.1PrevalenceofUnhealthyStatusin2020and2021YearsComparedtoPre-Pandemic2019Year 42

8.2PrevalenceofPoorHealthAmongCOVID-19Survivors 47

Section9:Acknowledgments 52

AppendixA:DataSourceandDataPreparation 54

A.1NHISOverview 54

A.2OverviewofVariablesCollectedintheNHIS 55

A.3DataPreparation 57

AppendixB:MeasuresofHealth.LiteratureReviewandDefinitions 59

B.1MeasuresofGeneralHealth:Self-RatedHealth 59

B.2MeasuresofGeneralHealth:RockwoodFrailtyIndex 59

B.3ListofDeficitstoCalculateFrailtyIndexforNHISSurveysConductedBefore2019 62

B.4SpecificMeasuresofHealthImpairment 64

B.5ListofDeficitstoCalculateFrailtyIndexfortheNHISConductedin2019-2021 66

AppendixC:PeriodLifeTables 67

C.1MethodologyofLifeTableConstruction 67

C.2NotesonLifeTableConstructionforSmallPopulations 70

C.3ValidationofLifeTableConstructionMethod 71

C.4DecompositionMethodofLifeExpectancy 72

AppendixD:LifeTablesExcelFile 74

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AppendixE:Limitations 75

AboutTheSocietyofActuariesResearchInstitute 79

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UnhealthyLongevityintheUnitedStates

AStudyofMortalitybyHealthStatus

Introduction

Thepurposeofthisreportistoquantifydifferencesinmortalityanddiseaseprevalencebyhealthstatus.This

projectwasconductedinresponsetoarequestfromtheSocietyofActuaries(SOA)MortalityandLongevitySteeringCommitteeandisintendedtoassistbothpracticingactuariesandthepublictobetterunderstanddifferencesin

mortalityforpeopleingoodandpoorhealth.

Thisprojectusesfivedefinitionsofunhealthystatus,thefirsttwoofwhicharebroad:(1)poororfairself-rated

healthand(2)FrailtyIndex(FI)valuesequaltoorhigherthan0.2(FI≥0.2).Thethreespecificdefinitionsincluded

(1)mentalconditions,(2)disabilityoractivitylimitationsand(3)presenceofchronicdiseases(basedonalistofninediseases).A“healthy”groupwasalsostudiedforcomparisonpurposes.

TheNationalHealthInterviewSurvey(NHIS),oneofthelargestU.S.healthsurveys,wasusedasasourceofdatafortheU.S.populationhealth.Estimatesofmortalityratesforunhealthyandhealthygroupsofadults(ages45and

over)werestratifiedbysexandperiod.Mortalityestimatesbyhealthstatuswereobtainedfortworecentperiods:2010–2014and2015–2018.Age-specificprevalencebyhealthstatuswasestimatedfor2010–2021toincludeyearsimpactedbyCOVID-19.

Theprojectresultswereexpressedintheformoflifeexpectanciesandlifetablesusingaspectrumofindividualhealthmeasures.

ExecutiveSummary

KEYTAKEAWAYS

1.Incomparingtheunhealthyandhealthygroups,regardlessofdefinitionemployed,mortalitywasmuchworsefortheunhealthygroup.

2.Thementalconditionssubgrouphadworselifeexpectancyatage45versusthedisabilityandthechronicdiseasesubgroups.

3.Personswiththreeormorechronicdiseaseshadasignificantincreaseinmortalityversusindividualswithoneortwochronicdiseases.

4.Theself-ratedhealthdefinitionprovedtobejustasgoodofameasureforbeingunhealthyasthemoresophisticatedFrailtyIndexdefinition,whichisbasedon64healthconditions.

5.AhigherprevalenceofpoorhealthwasfoundamongrespondentswhohavehadCOVID-19versusrespondentsindicatingtheyneverhadCOVID-19.

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ANALYSISOFKEYTAKEAWAYS

Unhealthygroupshavemuchhighermortalityandshorterlifeexpectancythanhealthygroups.Thedifferenceinlifeexpectancyatage45betweenhealthyandunhealthysubgroupsusingboththeFrailtyIndexandself-ratedhealth

measuresexceeds15yearsforbothsetsofdataperiodsandforbothmalesandfemales.

Additionallyinexaminingthethreetypesofspecifichealthimpairments,mentalhealth(memoryimpairments)

resultedinthelargestdecreaseinlifeexpectancyatage45.In2015–2018,thelifeexpectancyestimatesatage45were21yearsformalesand25yearsforfemalescomparedto35yearsformalesand44yearsforfemaleswithoutmemoryimpairments.Althoughdisabilityaccountedforthesecondlargestportionoflifeexpectancydecline,thepresenceofchronicdiseaseshadasmallereffectonthelifeexpectancydecreaseamongunhealthysubgroups.Lifeexpectancyestimatesatage45forpersonshavingandnothavingchronicdiseaseswere31versus40yearsfor

malesand39versus45yearsforfemales(Table7).

Analysisofmortalityforpersonshavingthreediseasesormoreshowedanassociationwithasignificantincreaseinmortality.In2015–2018,lifeexpectancyatage45droppedfrom35yearsformaleswithonediseaseto22yearsformaleswiththreeormorediseases.Forfemales,lifeexpectancyatage45droppedfrom36yearsto28years.

Lifeexpectancyat45forunhealthygroups(accordingtoself-ratedhealthandFrailtyIndex[FI]measures)showedadeclineovertimewiththeexceptionoffemaleshavingFI≥0.2.Malesandfemaleswithmemoryimpairmentsandfemaleswithchronicdiseasesdemonstratedanincreaseoflifeexpectancyat45.Malesandfemaleswithdisabilityandmaleswithchronicdiseaseshowedadeclineinlifeexpectancyat45overtime.Allchangesoflifeexpectancyovertimeweresmallandnotstatisticallysignificantforallstudiedhealthgroups.

Thecomparisonofage-specificmortalitytrajectoriesfoundaremarkablesimilarityintrajectoriesbetween

unhealthygroupsbasedonself-ratedhealthandFrailtyIndexdefinitionsofhealth.Itturnsoutthattheverysimple

definitionbasedonself-ratedhealthproducedvirtuallythesamemortalitytrajectoryasusingafarmoresophisticateddefinitionbasedontheFrailtyIndexwith64health-relatedquestions(seeFigureE1).

FigureE1

AGE-SPECIFICMORTALITYINLOGSCALEFORMALESANDFEMALESIN2015–2018ACCORDINGTODIFFERENT

U.S.Females

——SRH,healthy——SRH,unhealthy

FI<0.2——FI≥0.2

Total

0.100

0.010

0.001

45-4955-5965-6975-7985+

DEFINITIONSOFHEALTH:(1)SELF-RATEDHEALTH(SRH)AND(2)FRAILTYINDEX(FI)WITHCUTOFFEQUALTO0.2

U.S.Males

——SRH,healthy——SRH,unhealthy

FI<0.2——FI≥0.2

Total

0.100

0.010

0.001

45-4955-5965-6975-7985+

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ThisprojectanalyzednewlyreleaseddataonhealthdistributionintheCOVID-19pandemic(2020–2021)andpre-pandemic(2019)years.TheNHISquestionnairesin2019–2021aremarkedlydifferentfromthequestionnairesin2018andearliersurveys.Forthisreason,onlythetrendsinhealthindicatorsusing2019–2021datawerestudied.Thiscomparisonshowedanoticeableincreaseintheprevalenceofmentalconditionsin2021comparedto2019and2020.Nonoticeabledifferenceswereobservedfordisability,chronicdiseases,self-ratedhealthandFrailty

Index.

ThedirecteffectsofCOVID-19onhealthwereanalyzedbycomparingCOVID-19survivorswithrespondentswhohadnothadthisdisease.AsignificantincreasewasseeninpoorhealthamongrespondentseverhavingCOVID-19forthosewithmentalconditions,chronicdiseases,self-ratedhealthandfrailty.ForCOVID-19survivorswitha

disability,COVID-19hadnonoticeableeffectonhealth.

OTHERANALYSISHIGHLIGHTS

Changesinlifeexpectancyofunhealthygroupsbetween2010–2014and2015–2018wereverysmall.Similarly,nodifferencewasfoundintheorderofthelifeexpectanciesforthethreegroupsofunhealthyliveswhenmovingfromage45toage65.

Utilizing2015–2018data,thetotaldifferenceinlifeexpectancybetweenhealthyandunhealthysubgroups

accordingtoself-ratedhealthatage45is18years.Thedecompositionoflifeexpectancyatage45yearsshowedthatofthese18years,deathsduetocancercontributefiveyearsanddeathsduetocardiovasculardisease(CVD)contributefouryearstothedifference.Thus,inthecaseofself-ratedhealth,cancerandCVDdeathscombinedrepresenthalfoftheexcessmortalityatage45.

Thetotaldifferenceinlifeexpectancybetweendisabledandnotdisabledsubgroupsatage45is23years.Ofthese23years,deathsduetoCVDcontributesixyearsanddeathsduetocancercontributefiveyears.Thus,inthecaseofdisability,CVDcontributesslightlymorethancancertodifferencesinlifeexpectancybetweendisabledandnot

disabled(unliketheself-ratedhealth).

Thecomparisonoftheprevalenceofpoorhealthstatusbyraceshowedthatage-specificprevalenceofthe

unhealthygroupwasalmostalwayssignificantlyhigheramongtheBlackorAfricanAmericanpopulation(hereafterBlackwillbeusedforbrevity)comparedtothewhitepopulation.Overall,age-specificprevalenceofunhealthy

groupsishigheramongtheBlackpopulationcomparedtothewhitepopulationforallstudieddefinitionsofhealth.

DifferencesinprevalenceofpoorhealthstatusbetweentheBlackandwhitepopulationswerehigherwhenusingtheself-ratedhealthmeasureforunhealthystatusthanwhenusingmoreobjectivemeasuresofunhealthystatussuchaschronicdiseasesanddisability.Prevalenceofunhealthystatusforthe“Other”racialgrouptendstobe

closertothewhitepopulationatyoungeragesandtotheBlackpopulationatolderages.

ThestudyofprevalenceaccordingtohealthstatusbyregionshowedsomewhathigherprevalenceofunhealthygroupsintheSouthregioncomparedtootherregions.Thisobservationagreeswithexistingreportsofhighermortalityandlowerlifeexpectancyinthisregion.

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Section1:DefinitionofHealthyandUnhealthyStatus

Thepurposeofthisprojectwas“toanalyzedifferencesinmortalitypatternsandtrendsbetweenhealthyand

unhealthylivesintheU.S.”asformulatedinthecallbytheSocietyofActuary(SOA)forproposals.Toanalyzethe

mortalityofhealthyandunhealthyindividualsitisimportanttodefinehealth.Manyapproachescouldbefoundforsuchdefinitions.Definitionsofhealthcanconsidermultipledimensions,ortheycanbebasedonasingle

dimension(Crimmins2015).TheFrailtyIndex(FI)isanexampleofamultidimensionalmeasureofhealth

encompassingindicatorsofdisability,diseaseandriskfactors.Similarly,self-ratedhealthisabroadmeasureof

health,butitisbasedonanindividual’sperception,andweassumepeopleincludeallofthesefactorsintheir

assessment.Anotherapproachistoconsideronedimensionofhealthatatime,suchasdisability,mentalconditionsorthepresenceofchronicdiseases.Forthisreport,weconsideredmortalityofunhealthyandhealthygroupsoftheU.S.populationusingbothbroaderandspecificdefinitionsofhealth.AliteraturereviewoftheexistingmeasuresofhealthstatusisavailableinAppendixB.1.

Inthisstudywewerelimitedbytheavailabledatainchoosinghowtodefinehealthyandunhealthystatus.We

assessedtheavailableinformationintheNationalHealthInterviewSurvey(NHIS)andmadechoicesthatwethinkreflecthealthyandunhealthydefinedinmultipleways.Weusedthefollowingdefinitionsofpoorgeneralhealth:

?Self-ratedhealthasfairorpoor.Thisdefinitionofpoorhealthisoftenusedinthescientificliterature.Itwasusedhereforcomparisonwithmoresophisticateddefinitions.Self-ratedhealthisoneoftheoldestmeasuresofhealthstatus.Respondentsaretypicallyaskedtoratetheirperceivedhealthusingafive-pointLikertscale(excellent,verygood,good,fair,poor).Thesefivegroupsareoftencombinedintothreegroups(very

good/excellent,good,fair/poor).Thisisthesimplestwaytomeasureindividualhealthstatus,anditwasshown

tobeagoodpredictorofsubsequentmortality(IdlerandKasl1991,DeSalvo,Bloser,Reynolds,HeandMuntner2005).

?FrailtyIndexequalto0.2orhigher.Empiricalstudiesestimatedthatthecutoffvalueof0.2isrecognizedby

multiplefrailtymeasuresasapproachingafrailstate(Rockwood,etal.2005,RockwoodandMitnitski2006,

Kulminski,Ukraintseva,Akushevich,ArbeevandYashin2007),sothatindividualscanbeclassifiedashavingnofrailty(FI<0.2)andfrail(FI=0.2–1.0).CalculationsoftheFrailtyIndexwerebasedonquestionsavailableintheNHISSampleAdultfile,whichprovidesindexestimatescomparabletothepublishedestimates.Sixty-four

questionsreflectingthreedomainsofhealthwereused:(1)medicalconditions(arthritis,cancer,diabetes

mellitusandothers),(2)healthconditionscausingdifficultywithactivity(hearingdifficulties,poorcognitionetc.)and(3)health-relatedbehaviorssuchassmoking.Overall,theFrailtyIndexcalculationwasbasedon64possiblehealthconditions(deficits)listedinAppendixB.3.DetailsofthecalculationincludingtreatmentofmissingvaluesaredescribedinAppendixB.2.

Inadditiontomeasuresofgeneralhealththisprojectstudiedmortalitybyhealthstatususingthreemorespecificdefinitionsofhealth.Specificdefinitionsofhealthconsideredinthisstudyincludethefollowingthreegroupsofhealthimpairment:(1)disability,(2)mentalconditionsand(3)presenceofchronicdiseases.

Inthisprojectmortalitypatternswerestudiedusingthefollowingspecificdefinitionsofhealth:

Disability.DisabilitywasdefinedashavinganylimitationofactivitymentionedbyaNHISrespondentincluding

activitiesofdailyliving(ADLs)andinstrumentalactivitiesofdailyliving(IADLs)anddifficultyremembering.This

definitionincludesbothphysicalandmentaldisability,whichisinlinewiththedefinitionappliedbylong-termcareinsurance(Stallard2019).

Mentalconditions.Mentalconditionsweredefinedasapositiveanswertoatleastoneofthequestions:(1)Personislimitedbydifficultyremembering;(2)Intellectualdisabilitycausesdifficultywithactivity;(3)Senilitycauses

difficultywithactivity[ICD-9codeforsenilityis797,Senilitywithoutmentionofpsychosis];(4)

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Depression/anxiety/emotionalproblemcausesdifficultywithactivity;and(5)Othermental

conditions/ADD[attentiondeficitdisorder]/bipolar/schizophreniacausesdifficultywithactivity.Memory

impairments(questions1and3)werealsostudiedseparately.IntheNHISquestionnaireallmentionedmentalconditionswereassociatedwithdifficultyofactivity.

Presenceofchronicdiseases.Chronicdiseasesweredefinedasapositiveresponsetoatleastoneofninequestionswhetherrespondenteverhasbeentoldthatheorshehashypertension,coronaryheartdisease,anginapectoris,

heartattack,heartcondition/disease,stroke,emphysema,cancerordiabetes.Theseninediseaseswerechosenoutof12diseasesmentionedintheNHISbecauseoftheirstrongassociationwithaging-relatedmortality.

Foreachofthesehealthsubgroupsage-specificmortalityandremaininglifeexpectancywereestimated.Estimatesweredoneformalesandfemalesseparately.

Section2:TheSourceofInformationonPopulationHealth

SeverallargenationallyrepresentativesurveyscollectindividualhealthinformationsuchasNationalHealth

InterviewSurvey(NHIS),HealthandRetirementStudy(HRS),GeneralSocialSurvey(GSS)andNationalHealthandNutritionExaminationSurvey(NHANES).ComparabilityofmortalityestimatesbasedonthesesurveysandtheU.S.vitalstatisticsdemonstratedagoodconsistencyacrosstimeintheNHISandHRSbutnotGSS(Keyes,Rutherford,Popham,MartinsandGray2018,Brown,LariscyandKalousová2019).WhencomparingtheNHISandHRSsurveys,itshouldbeconsideredthattheHRScollectsdataforrespondentsolderthan50yearswhereastheNHIScollectsdataforadultsaged18yearsandolder.Also,theNHISisconductedeveryyearratherthanbiannuallyastheHRSandhasalargersamplesize.

ComparisonofseveralpopulationsurveysbroughtustotheconclusionthattheNHISisoneofthebestsourcesofdataonU.S.populationhealth.ItisconductedbytheCentersforDiseaseControlandPrevention’sNationalCenterforHealthStatistics(CentersforDiseaseControlandPrevention2016).Thisisanannualcross-sectionalhouseholdinterviewsurvey,whichprovidesdemographic,socioeconomicandhealthcharacteristicsofthecivilian,

noninstitutionalizedpopulationintheUnitedStates.SamplingandinterviewingfortheNHISarecontinuousthroughouteachyear.TheNHISisconductedinaface-to-faceinterviewformat.Toincreasetheprecisionof

estimatesoftheBlackorAfricanAmerican(hereafterBlackwillbeusedforbrevity),Hispanic/LatinoandAsian

Americanpopulations,thecurrentNHISsampledesign(startingin2006)oversamplesBlackpersons,Hispanic/LatinopersonsandAsianAmericanpersons.

TheNHIShasrichinformationonthehealthstatusofrespondents.Itasksrespondentsaboutself-ratedhealthandhasasetofquestionsonhealthconditionsandADLsthatallowsresearcherstoestimatetheFrailtyIndex.TheNHIShasmorethan64questionsonhealthstatusandlimitationofactivityandhealthbehaviors.Summarizing,theNHISprovidesallnecessaryinformationforcalculatingtheRockwoodFrailtyIndexscore,whichiscomparabletoscoresobtainedinotherstudies(Biritwum,etal.2016,Rockwood,etal.2017,Mousa,etal.2018).Italsoincludesseveralquestionsonmentalconditions.

TheNHISmadesignificantchangesofitsquestionnairein2019sothatdefinitionsofmentalconditionsanddisabilityin2019becameincompatiblewithearlierNHISquestionnaires.HealthmeasuresforFrailtyIndex,disabilityand

mentalconditionswereupdatedtoreflectanewNHISquestionnaireintroducedin2019(seeAppendixB.4andB.5).In2020and2021NHISquestionnairesaskedrespondentsiftheyhavehadCOVID-19.ThisinformationwasusedtocomparehealthstatusamongthosewhohadCOVID-19withthosewhohadnothadthisdisease.Thishasbeen

doneforthewholespectrumofhealthstatusmeasuresmentionedabove.

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In2022theNHISreleasedinformationonrespondents’deathsintheformof2019Public-UseLinkedMortalityfilesandallowedustoestimatemortalityofrespondentsbyhealthstatus.Mortalitybyhealthstatuswasestimatedfortworecentperiodscorrespondingtoyearswhenthesurveywasconducted:2010–2014and2015–2018.In2010–2014,5,811deathswererecordedoutof90,404respondentssurveyedin2010–2014andaged45yearsandover.In2015–2019therewere4,404deathsoutof70,678respondentsaged45yearsandoverandsurveyedin2015–2018.

Section3:ConstructionofPeriodLifeTables

Unhealthylongevityinthisprojectwasanalyzedbyconstructionofcross-sectionalorperiodlifetables.Constructionofperiodlifetablesisastandardwayofpresentingmortalitydataindemography(Prestonetal.2001).Withthis

approach,periodlifetablesandlifeexpectanciesinthisreportwerecalculatedinamannerdifferentfromthatwithwhichsomeactuariesareaccustomed.Periodlifetablesshowsurvivalofhypotheticalratherthanrealbirthcohorts.

Lifeexpectancyofahypotheticalbirthcohortshowstheaveragenumberofyearsababyborninaparticular

populationcanbeexpectedtoliveifitexperiencesthecurrentage-specificmortalityratesofthatparticular

populationthroughoutitslife.Itdoesnotreflecttheexpectationsoflifeforarealcohortofindividualsatagivenage.1

Thesetablesaretypicallybasedonofficialgovernmentalsourcesofpopulationcountsanddeathcounts.Cross-sectionalmortalityratescanbeestimateddirectlyusingastandarddemographicapproachwhentheannual

numberofdeathsinaparticularagegroupisdividedbytheexposureinthisagegroup.Thisapproachisappliedlessoftentosurveysdatacomparedtoacohortapproach,althoughexamplesofitssuccessfulapplicationdoexist

(Manton,StallardandCorder1997,Arias,Escobedo,Kennedy,FuandCisewski2018,Steensma,Choi,LoukineandSchanzer2018).Across-sectionallifetableapproachtodataonhealthwasalsoappliedinthestudyof

multimorbidityandmortalityusingMedicaredata(DuGoff,Canudas-Romo,Buttorff,LeffandAnderson2014).This

approachhasnotbeenwidelyappliedtosurveydataalthoughitmaybepromisingforobtainingnationallyrepresentativemortalityestimates.

Aperiodlifetableisthemosteffectivewayofsummarizingmortalityexperienceofapopulationandcanalsobeusedtomakestatisticalinferencesandcomparisonsbetweenmortalityexperienceofdifferentpopulations.The

methodologyusedinthisprojectapplieslifetableconstructionforsmallareaswithasmallpopulationsize(EayresandWilliams2004,Eayres2017)andusedmethodsdescribedbyChiang(Chiang1978,1984).ThemethodologyofperiodlifetableconstructionisdescribedinAppendixC.1.

Constructionofperiodlifetableshascertainadvantagescomparedtoastandardcohortapproach:

?Itispossibletostudychangesinmortalityandlifeexpectancyovertimeinastandardmanner.

?Itispossibletostudymortalityoverlongeragespans(e.g.,fromyears45to85andolder).

1Readersneedtocorrectlyinterpretthelifeexpectanciesinthisreport.Twointerpretationsareconsidered:

1.Forindividualsmatchedonage,sexandothercharacteristics,lifeexpectancyrepresentstheaverageremainingnumberofyearstobelivedbysuchindividuals.Generally,halflivelongerandhalflessthantheindicatedvalue.

2.Forapopulationofindividualsatdifferentattainedageswhoarematched,atthoseages,onsexandothercharacteristics,mortalityoverthenextyearcanyieldasetofage-specificdeathratesandanassociatedlifeexpectancythatservesasasummarizationofthoseage-specific

deathrates.Inthesecondcase,thelifeexpectancyvalueistiedtothegivensetofmortalityrateswithoutassumingthattheentiresetofratesappliestoanygivenindividualorgroup.

Thefirstinterpretationappliestocohortlifetables.Thesecondinterpretationappliestoperiodlifetables.Thelatteristheintendedinterpretationforthelifeexpectanciesinthisreport.

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?Itispossibletocomparemortalityindifferentsubgroupsinastandardmannerusingsuchconventionalindicatorsasremaininglifeexpectancy.

Itisimportanttonotethatperiodlifetableshavecertainlimitationsinthecurrentapplicationbecausetheydonottakeintoaccountpossibletransitionsbetweenthestudiedhealthyandunhealthystatuses.Thecalculationsassumethatallinitiallyhealthypersonsareexposedtothemortalityschedulesonlyforhealthypersons,andallinitially

unhealthypersonsareexposedtothemortalityschedulesonlyforunhealthypersonsforallagesanddurations.Inactuality,substantialchangesingroupmembershipoccurovertimewiththepredominantdirectionofchangebeing

fromhealthytounhealthy.TheNHISdatadonotpermitustostudysuchtransitions.Thus,itisimportantin

interpretingtheresultstorememberthatsuchtransitionsarenotincludedinthecalculations.(seeAppendixEformoredetails).

TheNHIShasinformationaboutdeathcountsforeachsurveycohortfolloweduntil2019.Thisinformationcanbe

usedforcohortanalysisofmortality.Atthesametime,thesedatacanalsobeusedforperiodlifetableconstructionusingexistingmethods.Inthisprojectweusedastandardmethodoflifetableconstructionwithsomemodificationstakingintoaccounttherelativelysmallsizeofthepopulationandthewaythissurveyhasbeenconducted.The

numberofdeathswascalculatedasdeathsoccurringduringthefirstfourquartersafterthesurveyinterviewinthe

age/healthstatus/sexsubgroup;thisreflectsthefactthatNHISinterviewswereconductedatdifferenttimesduringthesurveyyear.Thepopulationunderrisk(exposure)includedallrespondentsinaparticularageandhealth

subgroupminusone-halfofdeathsinthissubgroupdu