Statistical bulletin: Excess Winter Mortality in England and Wales : 2014… · 2016-04-28 · lowest in August and September 2014 and July 2015 (1,248, 1,282 and 1,232 respectively)

Statisticalbulletin:

ExcessWinterMortalityinEnglandandWales:2014/15(Provisional)and2013/14(Final)Morepeopledieinthewinterthanthesummer.Wepresentdatabysex,age,regionandcauseofdeath.

Contact:RosieAmery

Releasedate:25November2015

Nextrelease:Tobeannounced

Tableofcontents1. Mainpoints

2. Definitions

3. Excesswintermortality(EWM)trendsinEnglandandWales

4. Excesswintermortality(EWM)andtemperature

5. Excesswintermortality(EWM)andinfluenzarates

6. Excesswintermortality(EWM)bysexandage

7. Excesswintermortality(EWM)in2014/15byunderlyingcauseofdeath

8. Excesswintermortality(EWM)bygeography

9. Causesofexcesswintermortality

10. Methodologicalchanges

11. Policycontext

12. Usesofexcesswintermortality(EWM)data

13. ComparisonswiththerestoftheUK

14. References

15. Backgroundnotes

16. Methodology

MainpointsAnestimated43,900excesswinterdeathsoccurredinEnglandandWalesin2014/15;thehighestnumbersince1999/00,with27%morepeopledyinginthewintermonthscomparedwiththenon-wintermonths

Themajorityofdeathsoccurredamongpeopleaged75andover;therewereanestimated36,300excesswinterdeathsinthisagegroupin2014/15,comparedwith7,700inpeopleagedunder75

Thereweremoreexcesswinterdeathsinfemalesthaninmalesin2014/15,asinpreviousyears.Maleexcesswinterdeathsincreasedfrom7,210to18,400,andfemaledeathsfrom10,250to25,500between2013/14and2014/15

Respiratorydiseasesweretheunderlyingcauseofdeathinmorethanathirdofallexcesswinterdeathsin2014/15

TheexcesswintermortalityindexwashighestintheSouthWestin2014/15andjointlowestinYorkshireandTheHumber,andWales

1.

DefinitionsIncommonwithothercountries,inEnglandandWalesmorepeopledieinthewinterthaninthesummer.Thisstatisticalbulletinpresentsprovisionalfiguresforexcesswinterdeaths(EWD,alsoreferredtoasexcesswintermortality–EWM)inEnglandandWalesforthewinterperiod2014/15andfinalfiguresforthewinterperiod2013/14.Historicaltrendsfrom1950/51onwardsarealsoprovidedforcomparison.Figuresarepresentedbysex,age,regionandcauseofdeath.Informationontemperatureandinfluenzaincidenceisalsogiventoaddcontexttothemortalityfigures.

Methodforcalculatingexcesswintermortality

Excessdeaths

JohnsonandGriffiths(2003)(97.4KbPdf)investigatedseasonalmortalityandreportedthathistorically,aboveaveragemortalityistypicallyseenbetweenDecemberandMarch.Therefore,ourstandardmethoddefinesthewinterperiodasDecembertoMarch,andcomparesthenumberofdeathsthatoccurredinthiswinterperiodwiththeaveragenumberofdeathsoccurringintheprecedingAugusttoNovemberandthefollowingApriltoJuly:

EWM=winterdeaths-averagenon-winterdeaths

Thisproducesthenumberofexcesswinterdeaths(EWDs),whichisthenroundedtothenearest10forfinaldataandtothenearest100forprovisionaldata.

Excesswintermortality(EWM)index

TheEWMindexiscalculatedsothatcomparisonscanbemadebetweensexes,agegroupsandregions,andiscalculatedasthenumberofexcesswinterdeathsdividedbytheaveragenon-winterdeaths:

EWMIndex=(EWM/averagenon-winterdeaths)x100

TheEWMindexispresentedwith95%confidenceintervals,whicharecalculatedas:

EWMindex±1.96x(EWMIndex/√EWM)

TheEWMindexshowsthepercentageofextradeathsthatoccurredinthewinterandisreportedto1decimalplace.

MoredetailsabouthowEWMiscalculatedandhowtointerpretanduseconfidenceintervalsareavailableinBackgroundnotes2,3and4.

2.

Excesswintermortality(EWM)trendsinEnglandandWalesTherewereanestimated43,900excesswinterdeaths(EWDs)inEnglandandWalesin2014/15,representing27%moredeathsinthewinterperiod,comparedwiththenon-winterperiod.ThenumberofEWDswas2.5timeshigherin2014/15thantherecordlowof17,460EWDsin2013/14,andwasthehighestsince1999/00.

TheincreaseinEWMin2014/15appearsmorepronouncedpartlyasaresultofalowerthanaveragenumberofEWDsin2013/14incomparisonwithahigherthanaveragenumberofEWDsthisyear(2014/15).LargeannualfluctuationsinEWDsarenotuncommon,forexamplerecentlyEWDsincreasedbyalmost50%betweenthewintersof2007/08and2008/09andalsointhelate1990sitmorethandoubledbetween1997/98and1998/99.However,EWMin2014/15wasstillnotablyhigh.

HistoricaltrendsinEWDsinEnglandandWalesoccurringbetween1950/51and2014/15arepresentedinFigure1.Afive-yearmovingaverageisalsopresentedtosmoothoutanyshort-termfluctuations.ThisshowsthatasharpdropinEWDsoccurredbetween1960/61and1965/66,followedbyaslightincreaseandanothersharpdropbetween1969/70and1972/73.TheEWMthengraduallydecreased,albeitwithsomefluctuationsfrom1973/74upuntil1996/97.Therewererelativelyhighnumbersofdeathsinthewintersof1998/99and1999/2000,butdeathsdroppedsharplythefollowingwinter.ThisdecreasingtrendinEWMcontinueduntil2005/06.In2006/07,thesmoothedtrendlineincreasedslightlyandhasremainedrelativelystablesince.ItistoosoontosayifthesharpincreaseinEWMin2014/15isthebeginningofanupwardtrend.

3.

Figure1:Numberofexcesswinterdeathsandfive-yearcentralmovingaverage,EnglandandWales,1950/51–2014/15

Source:OfficeforNationalStatistics

Notes:EWMfiguresarebasedondeathsoccurringineachperiod(AugustthroughtothefollowingJuly).NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seebackgroundnote3inthestatisticalbulletin).

1.

Figuresforthelatestwinterareprovis ionalandareroundedtothenearest100,figuresforallotherwintersarefinalandareroundedtothenearest10.

2.

Centralmovingaverageswerecalculatedusingthewinterperiodofinterest,alongwiththetwowinterperiodsbeforeandtwoperiodsafter.

3.

Dataincludenon-residentswhodiedinEnglandorWales.4.

Excesswintermortality(EWM)andtemperatureNumberofdailydeathsAsinpreviouswinters,thepeakinmortalityin2014/15occurredatthebeginningofJanuary;howeveritwasnotablyhigherthaninpreviousyears.

Thenumberofdailydeathsin2014/15wasabovethefive-yearaveragethroughoutmostoftheyear(on304outof365days).Duringthewinterperiod,therewereonly2dayswherethenumberofdailydeathswasbelowthefive-yearaverage:2Decemberand18March.Throughthenon-wintermonthsthenumberofdailydeathswasgenerallysimilartothefive-yearaverage,butduringthewinterdailydeathswerefarhigher.

Around5December,thenumberofdailydeathsbegantoclimbnoticeablyhigherthanthefive-yearaverage.Thenumberofdailydeathspeakedon1January,andremainedabout30%aboveaverageuntil10January,andaround10%aboveaverageuntilearlyMarch.Fromthispeakon1January,thenumberofdailydeathsgraduallydeclineduntilthebeginningofAprilatwhichpointtheyreachedlevelssimilartothefive-yearaverage.Thenumberofdailydeathswashighestabovethefive-yearaverageon10January(38%higher).

4.

Figure2:Numberofdailydeaths,andfive-yearaveragedailydeaths,EnglandandWales,August2014toJuly2015


Notes:

Meannumberofdailydeathseachmonthandmeanmonthlytemperatures

Figuresarebasedondeathsoccurringeachday.NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnote3inthestatisticalbulletin).

1.

Fiveyearaveragesforeachdayarecalculatedusingdatafromthepreviousfiveyears,excludingthecurrentyear.

2.

Mortalitydataincludenon-residentswhodiedinEnglandorWales.3.

Figure3showsthatthemeannumberofdailydeathseachmonthwashigherthanthefive-yearaveragethroughout2014/15,butthisdifferencewassmallerinthenon-wintermonths.TheusualseasonalpeakinmortalityinDecemberandJanuarywasverypronouncedin2014/15,withmortalitylevels12%higherthanaverageinDecember,24%higherinJanuaryand11%higherinFebruary.Consistentwiththefive-yearaverage,thepeakinmonthlymortalityoccurredinJanuaryin2015withanaveragedailynumberofdeathsof1,916.ThemonthwiththesecondhighestmeannumberofdailydeathswasDecemberwith1,712deaths.MeandailydeathswerelowestinAugustandSeptember2014andJuly2015(1,248,1,282and1,232respectively).

Coldertemperatureswerenotthemaincauseoftheincreaseinwinterdeathsin2014/15,asthemeanmonthlytemperaturewasaboveaveragefromSeptemberthroughtoJanuaryandsimilarto,orslightlybelow,theaverageforallothermonths.Moreover,theaveragetemperaturebetweenOctoberandNovember2014,droppedfrom12.2°Cto8.2°C,butmortalityremainedsimilaracrossbothmonths(1,350deathsinOctober2014comparedto1,403deathsinNovember2014).Averagemonthlytemperatureswerelowerinallwintermonthsin2012/13thanin2014/15,andyetthemeannumberofdailydeathseachmonthwashigherin2014/15thanin2012/13.

Figure3:Meannumberofdailydeathseachmonthandmeanmonthlytemperatures,EnglandandWales,August2014toJuly2015

Source:OfficeforNationalStatistics,MetOffice

Notes:

Excesswintermortality(EWM)andaveragewintertemperature

Themeannumberofdailydeathsis basedondeathsoccurringineachmonth.NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seebackgroundnote3inthestatisticalbulletin).

1.

Fiveyearaveragesforeachmontharecalculatedusingdatafromthepreviousfiveyears,excludingthecurrentyear.

2.


Excesswinterdeaths(EWDs)in2014/15werethehighestsince1999/2000,whenfluconsultationrateswereveryhigh.Afteramildwinterin2013/14,thewinterof2014/15wascolderbycomparison.Howevertheaveragewintertemperatureof4.8°Cwasnotparticularlycoldcomparedwiththeprevious10years;duringthisperiodhalfofthewinterswerecolderandhalfwerewarmerthan2014/15.Theaveragenon-wintertemperaturewassimilartopreviousyears(12.4°C),aswasthenon-wintermortality.

Althoughitisoftenthoughtthemaincauseofexcesswinterdeathsistemperature,itisnottheonlyfactoraffectinglevelsofmortality.Thoughtemperatureclearlyhasarole,thelinkbetweenaveragewintertemperatureandEWDsisveryunclearinsomeyears.Forexample,winter2009/10wasexceptionallycold,butexcesswintermortality(EWM)wassimilartoyearswithmildwinters.Incontrast,thehighernumberofEWDsin2012/13waslikelytobeduetocoldweather,butitwastheunusualpatternofasustainedcoldfrommid-JanuaryuntilearlyApril,ratherthanjustacoldJanuaryperiod,thatinfluencedmortality.

Figure4:Numberofexcesswinterdeathsandaveragewintertemperature,EnglandandWales,1999/2000to2014/15

Source:MetOffice,OfficeforNationalStatistics

Notes:EWMfiguresarebasedondeathsoccurringineachperiod(AugustthroughtothefollowingJuly).NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seebackgroundnote3inthestatisticalbulletin).

1.


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Meanwintertemperatureis calculatedusingaveragemonthlytemperaturesfromDecembertoMarch.

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AgreaterproportionofhomesinEnglandnowhavemeasurestoimproveenergyefficiency,suchascavitywallinsulation,moderncentralheatinganddouble-glazingcomparedwith1996.In2013,80%ofhomeshadfulldoubleglazing,upfrom30%in1996.Morethanathird(37%)ofhomeshad200mmormoreofloftinsulationin2013,upfrom3%in1996.Approximately9.6milliondwellingshadcavitywallinsulationin2013,upfromlessthan3millionin1996.Thismeanshomesarebecomingmoreenergyefficient(DepartmentforLocalCommunitiesandGovernment,2015).Itmaybethattheoutdoortemperaturenowhaslessofaneffectonexcesswintermortality,asbetterinsulationandenergyefficiencymeansthathousesareeasiertoheatandkeepwarm,potentiallyresultinginmorestableindoortemperatures.Therehavebeenanumberofschemesaimedatreducingfuelpoverty,whicharesummarisedinthePolicyContextsectionbelow.

Excesswintermortality(EWM)andinfluenzaratesInfluenzaisarespiratorydisease(WorldHealthOrganisation,2008),causedbyaviralinfectionaffectingthelungsandairways.Influenzainfectionisassociatedwithpotentiallylifethreateningcomplications,suchasbacterialpneumonia.Theelderlyandthosewithunderlyinghealthconditionsareparticularlyatriskofdevelopingcomplications(PublicHealthEngland,2014b),whichcanresultinhospitalisationanddeath(PublicHealthEngland,2014c).Respiratorydiseaseisknowntobeoneofthemaincausesofexcesswinterdeaths(EWDs);forexamplein2014/15,respiratorydiseaseswaslistedtheunderlyingcauseofdeathfor36%ofallexcesswinterdeaths,withthemajorityofthesedeathsoccurringinthe75andoveragegroup.Pneumoniawastheunderlyingcausein19%ofallexcesswinterdeathsin2014/15.

AccordingtoPublicHealthEngland,moderatelevelsofinfluenzaactivityoccurredinthecommunityin2014/15,andtheyoccurredearlierinthe2014/15influenzaseasonthanthepreviousyear,withthepeakalsooccurringearlier.Theinfluenza-like-illness(ILI)consultationratepeakedinweek1at29.8consultationsper100,000population.Deathspeakedaweeklater,intheweekbeginning5January,whichisconsistentwiththelageffectdiscussedbytheEurowintergroup(1997).Theweekbeginning29Decemberandtheweekbeginning5January(weeks1and2of2015)had14,428and14,632deathsrespectively–35%and39%higherthanthesameweeksin2013/14.

Thepredominantinfluenzavirusinwinter2014/15wasinfluenzaA(H3N2).Thisstrainoffluhadaparticularlynoticeableeffectontheelderly,resultinginnumerouscare-homeoutbreaksandfarhigherlevelsofexcessmortalitythanthelastnotableH3N2seasonof2008/09(PublicHealthEngland,2015).Bycomparison,inthepreviouswinterof2013/14thepredominantinfluenzaviruswasinfluenzaA(H1N1),whichwasparticularlyvirulentinyoungerpeople(PublicHealthEngland,2014).

5.

Highlevelsofinfluenzaoccurredin1999/2000andwereassociatedwithahighlevelofmortality,asillustratedinFigure5.In2014/15influenza-like-illnessratesroseabovetheepidemicthresholdinweek50andremainedaboveoratthatthresholduntilweek14(PublicHealthEngland,2015).ChangesinthewaythethresholdiscalculatedmeanitisnotunusualfortheILIratetomoveabovethethreshold,andILI-levelsin2014/15werenowherenearthelevelsseenin1999/2000.

Levelsofinfluenzain2014/15werehigherthanrecentyears,aswerepeakintensivecarenumbers,butwerelowerthan2010/11whichsawveryhighlevelsofinfluenza(PublicHealthEngland,2015).Despitethis,EWMwashigherin2014/15thanin2010/11.In2010/11thepredominantinfluenzaviruswasA(H1N1),asin2013/14.OnereasonforthereducedEWMin2010/11whencomparedwith2014/15,isbecausethepredominantstrainofinfluenzain2014/15wasparticularlyvirulentinolderpeople,analreadyat-riskgroup,whilstin2010/11thepredominantstrainofinfluenzawasaparticularprobleminyoungerpeopleandhadlessimpactontheelderly(PublicHealthEngland,2014).Inadditiontothis,theinfluenzavaccinein2010/11wasaround50%effective(PublicHealthEngland,2011),comparedwiththe34%effectivenessin2014/15.Vaccineuptakesweresimilarin2014/15topreviousyears,thoughuptakewasslightlylowerthaninpreviousyearsinthoseunder65inaclinicalriskgroup(PublicHealthEngland,2015).

Figure5:WeeklydeathsfromallcausesandRoyalCollegeofGeneralPractitioners(RCGP)andPublicHealthWales(PHW)influenza-likeillness(ILI)consultationratesper100,000population,EnglandandWales,1999to2015


Notes:Figuresarebasedondeathsoccurringeachweek.NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnote3inthestatisticalbulletin).

1.

ThemethodforcalculatingILIrateschangedfordatafromweeknumber201431,soratesfromthis weekonwardsarenotdirectlycomparabletopreviousweeks.Formoreinformation,seethe'Changestothis bulletin'sectionofthestatisticalbulletin.

2.

Mortalitydataincludenon-residentswhodiedinEnglandorWales.3.

Excesswintermortality(EWM)bysexandageIn2014/15therewere43,900excesswinterdeaths(EWDs).Ofthistotal,42%weremalesofthetotal(18,400EWDs)and58%female(25,500EWDs).

Figure6comparestheexcesswintermortality(EWM)indexformalesandfemalesgroupedbyageforthelast3winters.TheEWMindexisusedtoshowhowmanymorepeoplediedinwinterthaninthenon-wintermonths,expressedasapercentage.Themajorityofthesedeathsforbothsexesoccurredamongstthoseaged75andover,withfemalesaged85andoverhavingthegreatestnumberofEWDs.FemaleEWDsaregenerallyhigherthanmales,especiallyinolderagegroups.Ahigherproportionofthefemalepopulationareaged75andover(9%,comparedwith7%ofmalesin2014),andwomenoutnumbermen2to1forpeopleagedover85(ONS,2015a).Thismaywholly,orpartially,explainthehighernumberofEWDsinwomen.

In2014/15EWMincreasedsignificantlyinallagegroupscomparedwith2013/14.EWMwasabout2.5timeshigherinbothmalesandfemalesin2014/15.TheEWMindexforfemalesincreasedto31%comparedwith24%formales.

AlthoughoverallasimilarincreaseinEWMwasseeninmalesandfemalesin2014/15,adifferentpatternemergeswhenweexaminethetrendsbyage.In2014/15biggerincreaseswereseeninmalesagedunder85,comparedwithfemalesinthisagegroup.Infact,thegreatestpercentageincreaseinEWMbetween2013/14and2014/15wasseeninmalesagedunder65:theEWMindexmorethantripledfrom4%to14%,withexcesswinterdeathsincreasingfrom660in2013/14to1,900in2014/15.Incontrast,femalesinthesameagegroupsawthesmallestpercentageincreaseinEWMincreasingfrom770to1,200.Womenaged85andoverhadabiggerincreaseinEWMin2014/15thanmeninthisagegroup.EWMinwomenaged85was2.8timeshigherin2014/15withtheEWMindexincreasingto41%;whereastheequivalentmaleEWMwas2.3timeshigherin2014/15(EWMindexof35%).

Figure6a:Excesswinterdeathsbysexandagegroup,EnglandandWales,2012/13to2014/15

Males

6.


Notes:EWMfiguresarebasedondeathsoccurringineachperiod(AugustthroughtothefollowingJuly).NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnotes2and3inthestatisticalbulletin).

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Thelowerandupperconfidencelimits (LCLandUCL)formaconfidenceinterval,whichis ameasureofthestatisticalprecis ionofanestimate.Moreinformationonthecalculationandinterpretationofexcesswinterdeaths,theexcesswintermortalityindexandconfidenceintervals canbefoundintheDefinitionssheet.

3.

Totals forallageswillnotbeequaltothesumoftheindividualagegroupsduetorounding.

4.

Theexcesswintermortality(EWM)indexis calculatedasexcesswinterdeathsdividedbytheaveragenon-winterdeaths,expressedasapercentage.

5.


Figure6b:Excesswinterdeathsbysexandagegroup,EnglandandWales,2012/13to2014/15

Females


Notes:EWMfiguresarebasedondeathsoccurringineachperiod(AugustthroughtothefollowingJuly).NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnotes2and3inthestatisticalbulletin).

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Totals forallageswillnotbeequaltothesumoftheindividualagegroupsduetorounding.

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Excesswintermortality(EWM)in2014/15byunderlyingcauseofdeathInpreviousbulletinsEWMhasonlybeenpresentedbyunderlyingcausedeathforthepreviouswinter,astheprovisionaldataforthemostrecentwinterisnotfullyqualityassured.However,weinvestigatedthisfurtheranddecidedthedataisofsufficientqualitytoproducereliableestimatesofEWMfor3broadcauses(circulatorydiseases,respiratorydiseaseandAlzheimer’sdiseaseanddementia)forthemostrecentwinter.Theseprovisionalestimateswillberevisedinnextyear’sbulletin.EWMforinjuryandpoisoningcanstillonlybeproducedforthepreviouswinter,duetothelongregistrationdelaysexperiencedforthesecauses,whichmakestheestimationmethodunreliable.MoreinformationisavailableintheQualityandMethodologypaper(437.8KbPdf).

RespiratorydiseaseisaleadingcauseofdeathinEnglandandWales,(ONS,2015a),anditalsohasthelargestseasonaleffectofallofthecausesincludedinTable1.In2014/15,78%morepeoplediedfromrespiratorydiseasesinthewinter,comparedwiththenon-winterperiod.Pneumoniaaccountedforthelargestproportionofthesedeaths.Thisissignificantlyhigherthanin2013/14,whentherewere30%morerespiratorydiseasedeathsinthewintercomparedwiththenon-winterperiod.Respiratorydiseasesalsocausedthelargestnumberofexcesswinterdeathsin2014/15(15,800),accountingforoverathirdofallEWDs.

Circulatorydiseaseswerealsooneofthemaincausesofmortalityin2014(ONS,2015a),andtheycausedalmostaquarterofallexcesswinterdeathsin2014/15(9,900).Therewasamoderateseasonaleffect–23%morepeoplediedfromcirculatorydiseasesinthewinterthaninthenon-wintermonths,upfrom11%in2013/14.However,thenumberofcirculatorydiseasedeathsremainshighthroughouttheyear,sotheseasonaleffectisnotaslargeasweseewitheitherrespiratorydiseasesordementiaandAlzheimer’sdisease.

7.

DementiaandAlzheimer’sdiseasewasoneoftheleadingcausesofdeathin2014(ONS,2015a),andalsodisplaysmarkedseasonaleffects.EWMfromthesecausesreachedarecordhighin2014/15,with9,100excesswinterdeaths.Theseasonaleffectwasmorethandoublethatseenforcirculatorydiseases,with52%morepeopledyingfromdementiaorAlzheimer’sdiseaseinthewinterthaninthenon-wintermonths,upfrom22%in2013/14.AnICD-10codingchangeintroducedinJanuary2014mayaccountforsomeofthisincrease,butnotall.Formoreinformation,seethe“MethodologicalChanges”section.ThereasonsfortheseasonalpatternindeathsfromdementiaandAlzheimer'sdiseasearenotclear.However,itmayberelatedtothegreatervulnerabilityofpeoplewiththeseconditionstorespiratorydiseases,difficultieswithself-care,andfalls,allofwhichmaybemoreimportantinwintermonths.

Similarrelationshipsbetweenunderlyingcauseandagecanbeseenforbothmalesandfemales.Referencetable1isamoredetailedversionofFigure7andshowsthenumberofexcesswinterdeaths(EWDs)andtheexcesswintermortality(EWM)indexinEnglandandWalesforthewintersof1991/92to2014/15,bysexandagegroupforcirculatorydiseases,respiratorydiseases,dementiaandAlzheimer’sdiseaseandinjuryandpoisoning(upto2013/14).

Figure7:Excesswintermortalityindexbyunderlyingcauseofdeath,EnglandandWales,2012/13to2014/15


Notes:Underlyingcauseofdeathis definedusingtheInternationalClass ificationofDiseases,TenthRevis ion(ICD-10).

1.

Figuresarebasedondeathsoccurringineachperiod(AugustthroughtothefollowingJuly).NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnote3inthestatisticalbulletin).

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3.

Amoredetailedvers ionofFigure7showingexcesswintermortality,brokendownbysexandagegroupcanbefoundintable1inthis Exceldocument.

4.

FiguresforEnglandandWalesincludedeathsofnon-residents.5.

Excesswintermortality(EWM)bygeographyExcesswintermortality(EWM),2012/13to2014/15byregionFigures8aand8bpresentstheexcesswintermortality(EWM)indexforEnglishregionsandWales,forwinter2012/13to2014/15.Moredetaileddatashowingthenumberofexcesswinterdeaths(EWDs)andtheEWMindex,brokendownbyageforregionsofEnglandandWales,from1991/92to2014/15,areavailableinReferenceTable2.

EWMincreasedsignificantlyineveryEnglishregionandWalesin2014/15,althoughthesizeofthisincreasevaried.Unlikewithothermortality-relateddatasets,suchassub-nationallifeexpectancy,EWMdoesnotshowaclear‘north/southdivide’.

Figure8a:ExcesswintermortalityforregionsofEnglandandWales,2014/15


Notes:

8.

Typically,regionalEWMisvariablewithnoconsistenttrendsacrosstime.Forexample,theNorthEasthadthelowestlevelofEWMcomparedwithotherregionsin2013/14,buthadrelativelyhighEWMin2014/15.

TheregionswithhighestEWMindexin2014/15weretheSouthWestandtheEastMidlands,whichhad29.9%and29.0%moredeathsinwintercomparedwiththenon-winterperiod.ThesewerebothsignificantlyhigherthantheEnglandandWalesaverageof27.2%.ThisisthethirdyearrunningthattheEastMidlandshashadoneofthehighestEWMindices,however,theSouthWestoftenranksmuchlower.

ThelargestincreaseintheEWMindexbetween2013/14and2014/15wasseenintheNorthEast,wheretheEWMindexnearlytripledfrom9.5%to28.3%,makingitthethirdhighestinEnglandandWalesin2014/15.

IncommonwiththeincreasingtrendsseenacrosstheEnglishregions,theEWMindexinWalesincreasedfrom10.3%in2013/14to25.4%in2014/15,withEWMlevelssimilartothoseseeninYorkshireandtheHumber(also25.4%)andtheWestMidlands(25.8%).

Figure8b:ExcesswintermortalityforregionsofEnglandandWales,2012/13to2014/15

EWMfiguresarebasedondeathsoccurringineachperiod.NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnotes2and3inthestatisticalbulletin).

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4.

FiguresforEngland,EnglishregionsandWalesexcludedeathsofpersonsusuallyresidentineacharea.FiguresforEnglandandWalescombinedalsoincludedeathsofnon-residents.

5.

BasedonboundariesasofAugust2015.6.


Notes:EWMfiguresarebasedondeathsoccurringineachperiod.NumbersofdeathsfromJanuarytoJuly2015areprovis ional,andhavebeenadjustedtotakeaccountoflateregistrations(seeBackgroundnotes2and3inthestatisticalbulletin).

1.


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4.

FiguresforEngland,EnglishregionsandWalesexcludedeathsofpersonsusuallyresidentineacharea.FiguresforEnglandandWalescombinedalsoincludedeathsofnon-residents.

5.

Excesswintermortality(EWM)in2013/14bylocalauthorityInformationpresentedearlierinthisbulletinreferstoprovisionalexcesswintermortality(EWM)figuresfor2014/15;thissectionreferstofinal2013/14EWMfiguresforlocalauthorities.LocalareaEWMdataarenotavailableforthemostrecentwinter(2014/15),asthesedataareprovisional,andtheestimationmethodusedtoproducenationalandregionalfiguresisnotreliableforsmallgeographicareas.

AswithregionalEWMfigures,thereisnoconsistentpatterninEWMacrosslocalauthoritiesinEnglandandWalesovertime.

ThelocalauthoritieswiththelowestEWMindexin2013/14wereFarehaminEnglandandTorfaeninWales.Infact,noEWMoccurredineitherlocalauthority;inFareham,thereweremoredeathsinthenon-wintermonthsthantherewereinthewinter.Thisprovidesagoodexampleofhowmuchindividuallocalauthoritiesvaryovertime,asin2012/13,therewere24%moredeathsinwintermonthscomparedwithnon-wintermonthsinFareham.

ThelocalauthoritywiththehighestEWMindexinEnglandin2013/14wasCityofLondon,where65%moredeathsoccurredinthewinter,thaninthenon-winterperiod,howevertheconfidenceintervalisverywideandrangesfrom11%to119%,soshouldbetreatedwithcaution.ThesecondhighestEWMindexinEnglandin2013/14wasChorleywith37%moredeathsinthewinterthanthenon-winter.InWales,BlaenauGwenthadthehighestlevelofEWM,with26%moredeathsinwintercomparedwiththenon-winterperiod.

BasedonboundariesasofAugust2015.6.

CausesofexcesswintermortalityAstudybyHealy(2003)showedthatexcesswintermortality(EWM)variedwidelywithinEurope.TheresultsshowthatcountrieswithlowwintertemperaturesinScandinaviaandNorthernEurope,suchasFinlandandGermany,hadverylowratesofEWM.Conversely,countrieswithverymildwintertemperaturesinSouthernEuropesuchasPortugalandSpainhadveryhighratesofEWM.EnglandandWalesbothhavehigherthanaverageEWMandexhibithighvariationinseasonalmortality.TheseresultswereechoedinamorerecentstudybyFowleretal(2014).

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Therearemanyreasonswhycountrieswithmilderwinterclimateshavesuchahighlevelofwintermortality.Forexample,peoplewholiveincountrieswithwarmerwinterstendtotakefewerprecautionsagainstthecold.TheEurowintergroup(1997)reportedthatcomparedwithpeoplelivingincountrieswithcoldwinters,thosefromwarmercountrieswerelesslikelytowearwarmprotectiveclothingincoldweather.

Countrieswithmilderwintersalsotendtohavehomeswithpoorerthermalefficiency(forexample,fewerhomeshavecavitywallinsulationanddoubleglazing),whichmakesithardertokeephomeswarmduringthewinter(Healy,2003).IthasbeenshownthatlowindoortemperatureisassociatedwithhigherEWMfromcardiovasculardiseaseinEngland(Wilkinsonetal.,2001).

AlthoughEWMisassociatedwithlowtemperatures,conditionsdirectlyrelatingtocold,suchashypothermia,arenotthemaincauseofEWM.Themajorityofadditionalwinterdeathsarecausedbycerebrovasculardiseases,ischaemicheartdiseaseandrespiratorydiseases.Althoughcancercausesmorethanaquarterofalldeathsannually,previousresearchbyJohnsonandGriffiths(2003)(97.4KbPdf)foundthattherewasnoclearseasonalpatternforthesedeaths.

Thecoldcanhavevariousphysiologicaleffects,whichmayleadtodeathinvulnerablepeople.Woodhouseetal(1993)reportedthatcolderhometemperaturewasassociatedwithincreasedbloodpressureinolderpeople.TheEurowintergroup(1997)notedthatcoldcauseshaemoconcentration,whichleadstothrombosis,andthatcoldcanalsolowertheimmunesystem’sresistancetorespiratoryinfections.Additionally,thelevelofinfluenzacirculatinginthepopulationincreasesinwinter.Invulnerablegroups,forexampleintheelderlyorthosewithpre-existinghealthproblems,influenzacanleadtolife-threateningcomplications,suchasbronchitisorsecondarybacterialpneumonia(PublicHealthEngland,2014b).

Previousresearchhasshownthatalthoughmortalitydoesincreaseasitgetscolder,temperatureonlyexplainsasmallamountofthevarianceinwintermortality,andhighlevelsofEWMcanoccurduringrelativelymildwintersBrownetal,2010(293KbPdf).CurwenandDevis(1988)showedthatbothtemperatureandlevelsofinfluenzawereimportantpredictorsofexcesswintermortality.Therelationshipbetweentemperature,influenzaandwintermortalityiscomplex.

MethodologicalchangesChangestothisbulletinAnumberofsmallchangeshavebeenmadetothebulletinsincethelastpublicationinNovember2014.Theseincludetheproductionofabackseriesofexcesswintermortalityfiguresbrokendownbyunderlyingcause.

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Inthisyear’sbulletinwehavecalculatedtheEnglandandWalesinfluenza-like-illness(ILI)ratesfromweek31of2014bycombiningdataprovidedbytheRoyalCollegeofGeneralPractitioners(RCGP-EnglandILIincidenceandpopulationdata)andPublicHealthWales(PHW-WalesILIincidenceandpopulationdata).InpreviousbulletinsthecombinedEnglandandWalesILIrateswereprovidedbytheRCGP.WehaveusedthesamemethodsastheRCGP,sothischangehashadminimalimpactonthefigures.

ChangestothecodingofunderlyingcauseofdeathWecodecauseofdeathusingtheWorldHealthOrganization's(WHO)InternationalClassificationofDiseases,TenthRevision(ICD-10).Wherepossible,deathsareautomaticallycodedusingspecialistsoftware,withtheremainingdeathsbeingmanuallycoded.ICD-10wasintroducedinEnglandandWalesinJanuary2001.SincethenvariousamendmentstotheICD-10havebeenauthorisedbyWHOandwehaveupdatedcausecodingsoftwaretoincorporatethesechanges.Between2001and2010,weusedsoftwareversion2001.2;between2011and2013,version2010wasusedandon1January2014,wechangedthesoftwaretoapackagecalledIRIS(version2013).IRISsoftwareversion2013incorporatesallofficialupdatestoICD-10approvedbyWHO,whichweretimetabledforimplementationbefore2014.

Tounderstandtheimpactofthesechangesonmortalitystatistics,wecarriedoutbridgecodingstudiesinwhichsamplesofdeathsthathadpreviouslybeencodedusingtheoldsoftwarewerethenindependentlyrecodedusingthenewversionofICD-10(ONS,2011and2014a).

Themovetov2010in2011hadabigimpactontheassignmentofdeathstoanunderlyingcauseof“MentalandBehaviouralDisorders”.Themajorityofthechangewastheresultofdeathspreviouslycodedas“DiseasesoftheCirculatorySystem”(I00–I99)inICD–10v2001.2nowbeingcodedasdeathsfromdementia(F01andF03)underv2010.Theincreaseinthedementiaandalzheimerscategorywas44%.Deathswithanunderlyingcauseofdeathcodedto“DiseasesoftheCirculatorySystem”decreasedby5%,whilethosecodedto“DiseasesoftheRespiratorySystem”showedanincreaseof2%.

ThemovetoIRIS(version2013)softwarein2014causedthenumberofdeathsallocatedto“DementiaandAlzheimer’sdisease”toincreaseby6.2%.Themainreasonforthisincreaseisthechangetothecodingofchestinfections,sodeathswhichmentionbothachestinfectionanddementiaorAlzheimer’sdiseasearenowallocatedanunderlyingcauseofdementiaorAlzheimer’sdisease,whereasinICD-10v2010(NCHS),thechestinfectionwouldhavebeenassignedastheunderlyingcause.Sincethiscodingchangeinvolveschestinfections,itsimpactislikelytobeslightlymorepronouncedinthewintermonths.Deathscodedwithanunderlyingcauseofdeathofcirculatorydiseasesdecreasedby0.7%betweenv2010andIRIS,anddeathscodedwithrespiratorydiseasesasanunderlyingcauseofdeathdecreasedby2.5%.

Thesecodingchangeswillnothaveaffectedtheoverallnumberofexcesswinterdeathsfromallcauses;norwillithavehadasignificantimpactontheexcesswintermortalityindexasanyimpactwillbespreadfairlyevenlythroughouttheyear.However,thecodingchangeswillhaveaffectedthenumberofexcesswinterdeathsforspecificcauses,withthebiggestimpactbeingfordementiaandAlzheimer’sdisease.Thismeansthatfiguresfor2011onwardsbyunderlyingcauseofdeathwillnotbedirectlycomparablewithfiguresfor2001to2010.

PolicycontextInthe2009annualreportfromtheChiefMedicalOfficer(CMO)forEngland,itwasnotedthat,althoughexcesswinterdeaths(EWDs)havedeclinedoverthelast50years,thenumberwasstilltoohigh(Donaldson,2010).TheCMOarguedthatmanyofthesedeathswerepreventableandthatmoreneededtobedonetoprotectvulnerablepeopleduringcoldwintermonths.

ThispromptedthegovernmenttodevelopanannualColdWeatherPlanforEngland,whichhasbeenpublishedyearlysinceNovember2011.PublicHealthEngland(PHE)publishedthe2015editioninOctober2015inpartnershipwithNHSEngland,theLocalGovernmentAssociationandtheMetOffice.TheColdWeatherPlanaimstopreventavoidableharmtohealthbyalertingpeopletothenegativehealtheffectsofcoldweather.Thisshouldenablethemtoprepareandrespondappropriately,andhelptoreducethenumberofexcesswinterdeaths.TheplansetsoutaseriesofactionstobetakenbytheNHS,socialcareandotheragenciesthroughouttheyear,andinresponsetoforecastoractualseverewinterweather.Italsoencourageslocalcommunitiestosupportthemostvulnerableintheirarea,suchascheckingonthemduringsevereweatherandofferingothersupport.TheMetOfficeissuescoldweatheralertsfromNovembertoMarchtosupporttheColdWeatherPlan(PublicHealthEngland,2015).The‘KeepWarmKeepWell’bookletprovidesadviceonstayingwellduringcoldweather,forexamplehealthylifestyle,heating,fluvaccinations,andmakingsurethatpeopleknowaboutallthebenefitsandservicestowhichtheyareentitled(PublicHealthEngland,2015).

TheUKgovernmentintroducedthe“greendeal”project,wherebyhouseholderscanhaveimprovementworkcarriedoutonheatingandhomeinsulation,paidbackthroughsavingsinenergybills.Thisaimstobenefitaround230,000lowincomefamiliesperyear(DepartmentofEnergyandClimateChange,2014a).InJanuary2013TheEnergyCompaniesObligationwasintroducedtoreducetheUK’senergyconsumptionandsupportpeoplelivinginfuelpoverty.Itwillfundenergyefficiencyimprovementswortharound£1.3billioneveryyearforlow-incomehouseholdsandareas,andinpropertiesthatarehardertotreat(DepartmentofEnergyandClimateChange,2014b).

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AnotherpolicyaimedathelpingthemostvulnerableheattheirhomesistheWarmHomeDiscountscheme(DepartmentofEnergyandClimateChange,2015).Thisisaone-offelectricitybilldiscountforpeopleonalowincomewhomeettheeligibilityrequirements.

Inaddition,thereareanumberofotherpoliciesaimedattacklingexcesswintermortality.Theseincludewinterfuelpayments(Directgov,2015),coldweatherfuelpayments(Directgov,2015),andtheseasonalfluvaccinationprogramme:nasalsprayfluvaccinesarenowavailableforallchildrenaged2,3and4(NHSChoices,2015).

TheWelshGovernmentalsorunsschemestoreducefuelpoverty,suchastheWelshGovernmentWarmHomesNest,whichisanall-Walesschemethatoffersanadvisoryservice,aswellashomeenergyefficiencyimprovementsforeligiblehouseholders.Eligiblehouseholdersarethoseonthelowestincomes,livinginthemostenergyinefficienthomes(Welshgovernment,2014a).Thisschemeiscomplementedbytheareabased“WelshGovernmentWarmHomesArbed”schemewhichseekstomakeenergyefficiencyimprovementstoWelshhomesinthemostdeprivedareas(Welshgovernment,2014b).

Usesofexcesswintermortality(EWM)dataExcesswintermortality(EWM)figuresarewidelyusedtoinformpolicy,planningandresearchinthepublicsector,inparticulartomeasuretheeffectivenessofcoldweatherplanning.LocalauthoritiesandpublichealthorganisationsacrossEnglandandWalesuseourdatatoassesslevelsofexcesswintermortalityintheirarea.Inaddition,charitiesuseexcesswintermortalitystatisticstosupportavarietyofcampaigns.

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ComparisonswiththerestoftheUKUKfiguresarenotavailableasweonlyholdmortalitydataforEnglandandWales.NationalRecordsofScotland(NRS)produceanannualwintermortalityreport.ScotlandsawsimilartrendstothoseinEnglandandWalesin2014/15,withwinter2014/15inScotland,likeEnglandandWales,havingthehighestnumberofexcesswinterdeathssince1999/2000.

NorthernIrelandStatisticsandResearchAgency(NISRA)producedareportonexcesswintermortality(EWM)for2013/14.The2014/15reportwillbepublishedon3December2015.

WintermortalityfiguresforScotlandandNorthernIrelandarebothbasedondeathregistrations,whereasEnglandandWalesfiguresarebasedonoccurrences.InScotlandadeathmustberegisteredwithin8days,andfactofdeathcanberegistered(withacausegivenasunascertained,pendinginvestigations)beforetheProcuratorFiscalhascompletedtheirinvestigations.Therefore,ScottishmortalitydataarenotsubjecttothesameregistrationdelaysasmortalitydataforEnglandandWales.AlmostalldeathsthatoccurredintherelevantperiodwillbeincludedintheScottishfigures,meaningwintermortalityfiguresfromScotlandarecomparablewithourfiguresforEnglandandWales.

ForNorthernIrelandmortalitydata,therecanbeasignificantdelaybetweenwhenthedeathoccurredandwhenitwasregisteredforsomecausesofdeath.NISRAhavecomparedEWMfiguresbasedonoccurrences,andregistrationsandthedifferenceisquitelargeinsomeyears.Therefore,EWMfiguresfromNorthernIrelandandEnglandandWalesarenotdirectlycomparable.

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References1. BrownG,FearnVandWellsC(2010)‘Exploratoryanalysisofseasonalmortality

inEnglandandWales,1998to2007’.HealthStatisticsQuarterly48,58–81,accessedon18October2014.

2. CurwenMandDevisT(1988)‘Wintermortality,temperatureandinfluenza:hastherelationshipchangedinrecentyears?’PopulationTrends54,17–20.

3. DepartmentforCommunitiesandLocalGovernment(2015)‘Englishhousingsurvey2013’accessed28thOctober2015

4. DepartmentofEnergyandClimateChange(2014a)Greendealpolicy,accessedon21stOctober2014

5. DepartmentofEnergyandClimateChange(2014b)EnergyCompanyObligationpolicy,accessedon21stOctober2014

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6. DepartmentofEnergyandClimateChange(2015)WarmHomeDiscountScheme,accessedon20thOctober2015

7. Directgov(2015)–Informationaboutwinterfuelpayments,accessedon20thOctober2015

8. Donaldson,L(2010)‘2009Annualreportofthechiefmedicalofficer–WinterKills’,31-27,accessedon24October2012

9. TheEurowintergroup(1997)‘Coldexposureandwintermortalityfromischaemicheartdisease,cerebrovasculardisease,respiratorydisease,andallcausesinwarmandcoldregionsofEurope’TheLancet349,1341–1346.

10. Fowleretal(2014)‘ExcesswinterdeathsinEurope:amulti-countrydescriptiveanalysis’.

11. HealyJD(2003)‘ExcesswintermortalityinEurope:acrosscountryanalysisidentifyingkeyriskfactors’,accessedon18October2014

12. JohnsonHandGriffithsC(2003)‘EstimatingexcesswintermortalityinEnglandandWales’,HealthStatisticsQuarterly20,19–24,accessed21stOctober2014(97.4KbPdf)

13. TheMetOffice(2015),Meanmonthlydata,accessedon13August2015

14. NHSChoices(2015)–Informationabouttheseasonalfluvaccine,accessedon20thOctober2015

15. ONS(2014)‘ExcesswintermortalityinEnglandandWales,2013/14(provisional)and2012/13(final)’,accessedon20thOctober2015

16. ONS(2015a)‘PopulationEstimatesforUK,EnglandandWales,ScotlandandNorthernIreland,Mid-2014’,accessedon20thOctober2015

17. ONS(2015b)‘MortalityStatistics:DeathsRegisteredinEnglandandWales(SeriesDR),2015’,accessedon28thOctober2015

18. Pebodyetal(2015)‘Effectivenessofseasonalinfluenzavaccineinpreventinglaboratory-confirmedinfluenzainprimarycareintheUnitedKingdom:2014/15endofseasonresults’,accessedon28thOctober2015

19. PublicHealthEngland(2011)‘SurveillanceofinfluenzaandotherrespiratoryvirusesintheUK:2010-2011report’accessed3rdNovember2015

20. PublicHealthEngland(2014)‘SurveillanceofinfluenzaandotherrespiratoryvirusesintheUnitedKingdom:Winter2013/14’,accessed28thOctober15

21. PublicHealthEngland(2015)‘SurveillanceofinfluenzaandotherrespiratoryvirusesintheUnitedKingdom:Winter2014/15’,accessed28thOctober15

22. PublicHealthEngland(2014b)‘Seasonalinfluenza:guidance,dataandanalysis’,accessed07November2014

23. PublicHealthEngland(2014c)‘SourcesofUKFludata-influenzasurveillanceintheUK’accessedon22ndOctober2014

24. PublicHealthEngland(2015)‘ColdWeatherPlanforEngland2015:Protectinghealthandreducingharmfromcoldweather’,accessedon20thOctober2015

25. PublicHealthEngland(2015)‘KeepWarmKeepWellcampaign’,accessed20thOctober2015

26. WelshGovernment(2014a)Nestfuelpovertyscheme,accessed22ndOctober2014

27. WelshGovernment(2013)Arbed-Strategicenergyperformanceinvestmentprogramme,accessed20thOctober2015

28. WilkinsonP,LandonM,ArmstrongB,StevensonS,PattendenS,McKeeMandFletcherT(2001)‘Coldcomfort:ThesocialandenvironmentaldeterminantsofexcesswinterdeathsinEngland,1986–96’,PublishedfortheJosephRowntreeFoundationbyThePolicyPress,Bristol.Accessedon15thOctober2013

29. WilkinsonP,PattendenS,ArmstrongBetal(2004)‘VulnerabilitytowintermortalityinelderlypeopleinBritain:populationbasedstudy’.BritishMedicalJournal,18,329,647–52,accessedon15thOctober2013

30. WoodhousePR,KhawKTandPlummerM(1993)‘Seasonalvariationofbloodpressureanditsrelationshiptoambienttemperatureinanelderlypopulation’.JournalofHypertension11(11),1267–74.

31. WorldHealthOrganisation(2008)‘ICD-10InternationalStatisticalClassificationofDiseasesandRelatedHealthProblems’accessed31October2014

Backgroundnotes1. Mortalitymetadata

Excesswintermortalityfiguresarederivedfromthedatacollectedwhendeathsarecertifiedandregistered.Informationabouttheunderlyingmortalitydata,includingdetailsonhowthedataiscollectedandcodedareavailableinthemortalitymetadata(2.46MbPdf).

2. Calculationofexcesswintermortalityfigures

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PreviousanalysiscomparedmethodsofcalculatingEWMusingdifferentwinterandnon-winterperiods,andfoundthatthedifferentmethodsproducedfairlysimilarresults.However,becauseourcurrentmethodincludesautumnandspringinthenon-winterperiod,ifmortalityishighinanyofthesemonths,ourestimateofEWMisdecreased(JohnsonandGriffiths,2003(97.4KbPdf)).

3. TheexcesswintermortalityextractandcalculationofprovisionalfiguresMortalitydatacomefromtheinformationcollectedwhenadeathisregistered.Mostdeaths(almost95%)areregisteredwithinonemonthofthedateofoccurrence,althoughviolentorunexpecteddeaths,whichneedfurtherinvestigationfromacoroner,cantakemuchlonger.SothattimelyEWMfigurescanbeproduced,wegenerateaspecialextractofmortalitydatainSeptemberfordeathsthatwereregisteredbythismonth,butwhichoccurreduptotheendofJuly.Thesefiguresarethenadjustedusingtheprovisionalnumberofdeathsfromthepreviousyear’sextract,comparedwiththefinalnumberofdeaths.ThisproducesaprovisionalestimatednumberofdeathsforJanuarytoJulyinthecurrentyearsothatEWMcanbecalculatedforthepreviouswinter.Asthesefiguresareprovisionaltheyareroundedtothenearest100andareonlyproducedataregionallevel.Finalfiguresareprovidedinthefollowingyear’sannualexcesswintermortalitystatisticalbulletin.Causeofdeathfigureshavebeenproducedusingfinalfigures(1991/92to2013/14)andareroundedtothenearest10.Figuresforlocalareasbasedonfinalfiguresfor2013/14arealsoavailabletodownloadfromourwebsite.

4. ConfidenceintervalsExcelworkbookscontainingthedatausedtoproduceFigures1to8areavailabletodownloadfromourwebsite.Whereappropriate,tablescontainthenumberofexcesswinterdeaths,theexcesswintermortalityindexandtheupperandlowerconfidencelimits.Theselimitsformaconfidenceintervalaroundtheindex,whichisameasureofthestatisticalprecisionofanestimateandshowstherangeofuncertaintyaroundtheestimatedfigure.Calculationsbasedonsmallnumbersofeventsareoftensubjecttorandomfluctuations.Asageneralrule,iftheconfidenceintervalaroundonefigureoverlapswiththeintervalaroundanother,wecannotsaywithcertaintythatthereismorethanachancedifferencebetweenthetwofigures.Withinthisstatisticalbulletinadifferencewhichisdescribedas“significant”means“statisticallysignificant”,assessedbyexaminingtheconfidenceintervals.

5. Leapyears

Theyears1992,1996,2000,2004,2008and2012wereleapyears,andsothemonthofFebruarycontained29daysinsteadof28.TheextradayinFebruaryhasbeentakenintoaccountinthecalculationofthemeannumberofdailydeaths,andthecorrespondingfive-yearaverageinFigure2.However,theextradayisnottakenintoaccountintheoverallcalculationofexcesswinterdeaths.Thismeansthatinleapyearsthewinterperiod(DecembertoMarch)willcontaindeathsforoneextraday.Itisestimatedthatbetween1,300and1,700deathsoccuron29February,thereforeinleapyears(forexample,thewinterof201112)therewillbearoundanextra1,500excesswinterdeathscomparedwithnon-leapyears.However,otherfactors,suchasverycoldwinters,andhighlevelsofinfluenzaactivityhaveafargreaterimpactontheoveralllevelofexcesswintermortalitythanleapyears.

6. BackdataupdateIn2015,abackseriesofdatafortable1wascreatedbackto1991/92sothatitwasinkeepingwithothertimeseries.Thisupdatewasfedintoseveralotherfigureswhicharemadeofasubsetofthesamedata,namelyfigures1,3,5and7.Itwasnotfoundtohaveaffectedthedatapreviouslypresentedinfigures1and3agreatdealwithamaximumchangeofanincreaseof200deaths2006/07.Themostnoticeablechangeswereseeninthemorerecentyearsduetodeathsbeingincludedthatwerenotyetregisteredatthetimethedatawaslastrevised.

7. SpecialextractsofdataSpecialextractsandtabulationsofexcesswintermortalitydataareavailabletoorderforacharge(subjecttolegalframeworks,disclosurecontrolandagreementofcosts,whereappropriate).Suchrequestsorenquiriesshouldbemadeto:MortalityAnalysisTeam,LifeEventsandPopulationSourcesDivisionOfficeforNationalStatisticsGovernmentBuildingsCardiffRoadNewportGwentNP108XGTel:+44(0)1633651639Email:[email protected]

8. RevisionsTheONSrevisionspolicyisavailableonourwebsite.

9. Pre-releaseaccessAlistofthenamesofthosegivenpre-publicationaccesstothestatisticsandwrittencommentaryisavailableinthispre-releaseaccesslistforExcesswintermortalityinEnglandandWales2014/15(Provisional)and2013/14(Final).Therulesandprincipleswhichgovernpre-releaseaccessarefeaturedwithinthePre-releaseAccesstoOfficialStatisticsOrder2008.

10. NationalStatistics

Contactdetailsforthisstatisticalbulletin

TheUKStatisticsAuthorityhasdesignatedthesestatisticsasNationalStatistics,inaccordancewiththeStatisticsandRegistrationServiceAct2007(393.8KbPdf)andsignifyingcompliancewiththeCodeofPracticeforOfficialStatistics.Designationcanbebroadlyinterpretedtomeanthatthestatistics:

meetidentifieduserneeds

arewellexplainedandreadilyaccessible

areproducedaccordingtosoundmethods

aremanagedimpartiallyandobjectivelyinthepublicinterest

OncestatisticshavebeendesignatedasNationalStatisticsitisastatutoryrequirementthattheCodeofPracticeshallcontinuetobeobserved.

11. FeedbackAsavalueduserofourstatistics,wewouldwelcomefeedbackonthisrelease.Inparticular,thecontent,[email protected].

12. SocialMediaFollowusonFacebookandTwitter.

13. TermsandconditionsYoumayuseorre-usethisinformation(notincludinglogos)freeofchargeinanyformatormedium,underthetermsoftheOpenGovernmentLicence.Toviewthislicence,visittheNationalArchiveswebsite,writeto:TheInformationPolicyTeam,TheNationalArchives,Kew,LondonTW94DU,oremail:[email protected].

14. Detailsofthepolicygoverningthereleaseofnewdataareavailablebyvisitingwww.statisticsauthority.gov.uk/assessment/code-of-practice/index.htmlorfromtheMediaRelationsOfficeemail:[email protected]

MethodologyExcesswintermortalityinEnglandandWalesQMI

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Documents

Statistical bulletin: Excess Winter Mortality in England and Wales : 2014… · 2016-04-28 · lowest in August and September 2014 and July 2015 (1,248, 1,282 and 1,232 respectively)