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CochraneDatabaseofSystematicReviews Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration (Review) EvansJR,LawrensonJG EvansJR,LawrensonJG. Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration. CochraneDatabaseofSystematicReviews2012,Issue6.Art.No.:CD000253. DOI:10.1002/14651858.CD000253.pub3. www.cochranelibrary.com Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. TABLE OF CONTENTS HEADER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 PLAINLANGUAGESUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 SUMMARYOFFINDINGSFORTHEMAINCOMPARISON . . . . . . . . . . . . . . . . . . . 3 BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 ADDITIONALSUMMARYOFFINDINGS . . . . . . . . . . . . . . . . . . . . . . . . . . 9 DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 AUTHORS’CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 CHARACTERISTICSOFSTUDIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 DATAANDANALYSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Analysis1.1.Comparison1Anyantioxidantversusplacebo,Outcome1AMD. . . . . . . . . . . . . . 38 Analysis1.2.Comparison1Anyantioxidantversusplacebo,Outcome2AdvancedAMD. . . . . . . . . . 39 Analysis2.1.Comparison2Alpha-tocopherolversusplacebo,Outcome1AMD. . . . . . . . . . . . . . 40 Analysis2.2.Comparison2Alpha-tocopherolversusplacebo,Outcome2AdvancedAMD. . . . . . . . . . 40 Analysis3.1.Comparison3Beta-caroteneversusplacebo,Outcome1AMD. . . . . . . . . . . . . . . 41 Analysis3.2.Comparison3Beta-caroteneversusplacebo,Outcome2AdvancedAMD. . . . . . . . . . . 42 APPENDICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 WHAT’SNEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 CONTRIBUTIONSOFAUTHORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 DECLARATIONSOFINTEREST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 SOURCESOFSUPPORT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 INDEXTERMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) i Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. [InterventionReview] Antioxidant vitamin and mineral supplements for preventing age-related macular degeneration JenniferREvans1,JohnGLawrenson2 1CochraneEyesandVisionGroup,ICEH,LondonSchoolofHygiene&TropicalMedicine,London,UK.2DivisionofOptometry &VisualScience,CityUniversity,London,UK Contactaddress:JenniferREvans,CochraneEyesandVisionGroup,ICEH,LondonSchoolofHygiene&TropicalMedicine,Keppel Street,London,WC1E7HT,[email protected]. Editorialgroup:CochraneEyesandVisionGroup. Publicationstatusanddate:Newsearchforstudiesandcontentupdated(nochangetoconclusions),publishedinIssue6,2012. Citation: EvansJR,LawrensonJG.Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration. CochraneDatabaseofSystematicReviews2012,Issue6.Art.No.:CD000253.DOI:10.1002/14651858.CD000253.pub3. Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. ABSTRACT Background Thereisinconclusiveevidencefromobservationalstudiestosuggestthatpeoplewhoeatadietrichinantioxidantvitamins(carotenoids, vitaminsCandE)orminerals(seleniumandzinc)maybelesslikelytodevelopage-relatedmaculardegeneration(AMD). Objectives ToexaminetheevidenceastowhetherornottakingantioxidantvitaminormineralsupplementspreventsthedevelopmentofAMD. Searchmethods WesearchedCENTRAL(which contains theCochrane EyesandVision GroupTrialsRegister) (TheCochrane Library2011, Issue 12),MEDLINE(January1950toJanuary2012),EMBASE(January1980toJanuary2012),OpenGrey(SystemforInformationon GreyLiteratureinEurope)(www.opengrey.eu/),themetaRegisterofControlledTrials(mRCT)(www.controlled-trials.com),Clinical- Trials.gov(www.clinicaltrials.gov)andtheWHOInternationalClinicalTrialsRegistryPlatform(ICTRP)(www.who.int/ictrp/search/ en).Therewerenodateorlanguagerestrictionsintheelectronicsearchesfortrials.Theelectronicdatabaseswerelastsearchedon26 January2012. Selectioncriteria We included all randomised controlled trials (RCTs) comparing an antioxidant vitamin and/or mineral supplement (alone or in combination)tocontrol. Datacollectionandanalysis Both review authors independently assessed risk of bias in the included studies and extracted data. One author entered data into RevMan5andtheotherauthorcheckedthedataentry.Wepooleddatausingafixed-effectmodel. Mainresults WeincludedfourRCTsinthisreview;62,520peoplewereincludedintheanalyses.ThetrialswereconductedinAustralia,Finland andtheUSAandinvestigatedvitaminEandbeta-carotenesupplements.Overallthequalityoftheevidencewashigh.Peoplewhotook thesesupplementswerenotatdecreased(orincreased)riskofdevelopingAMD.Thepooledriskratioforanyantioxidantsupplement inthepreventionofanyAMDwas0.98(95%confidenceinterval0.89to1.08)andforadvancedAMDwas1.05(95%CI0.80to 1.39).Similarresultswereseenwhentheanalyseswererestrictedtobeta-caroteneandalpha-tocopherolalone. Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 1 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. Authors’conclusions ThereisaccumulatingevidencethattakingvitaminEorbeta-carotenesupplementswillnotpreventordelaytheonsetofAMD.There is no evidence with respect to other antioxidant supplements, such as vitamin C, lutein and zeaxanthin, or any of the commonly marketedmultivitamincombinations. Althoughgenerallyregardedassafe,vitaminsupplementsmayhaveharmfuleffectsandclear evidenceofbenefitisneededbeforetheycanberecommended.PeoplewithAMDshouldseetherelatedCochranereview’Antioxidant vitaminandmineralsupplementsforslowingtheprogressionofage-relatedmaculardegeneration’writtenbythesamereviewteam. PLAIN LANGUAGE SUMMARY Antioxidantvitaminsandmineralsupplementstopreventthedevelopmentofage-relatedmaculardegeneration Age-related macular degeneration (AMD) is a condition affecting the central area of the retina (back of the eye). The retina can deterioratewithageandsomepeoplegetlesionsthatcanleadtolossofcentralvision.Somestudieshavesuggestedthatpeoplewho eatadietrichinantioxidantvitamins(carotenoids,vitaminsCandE)orminerals(seleniumandzinc)maybelesslikelytogetAMD. Theauthorsidentifiedfourlarge,high-qualityrandomisedcontrolledtrialswhichincluded62,520people.Thetrialswereconducted inAustralia,FinlandandtheUSAandinvestigatedtheeffectsofvitaminEandbeta-carotenesupplementation.Thesetrialsprovide evidencethattakingvitaminEandbeta-carotenesupplementsisunlikelytopreventtheonsetofAMD.Therewasnoevidencefor otherantioxidantsupplementsandcommonlymarketedcombinations.Althoughgenerallyregardedassafe,vitaminsupplementsmay haveharmfuleffectsandclearevidenceofbenefitisneededbeforetheycanberecommended. Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 2 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. CoAn SUMMARY OF FINDINGS FOR THE MAIN COMPARISON [Explanation] pyright©tioxidant 201vita AntioxidantsupplementcomparedwithplaceboforpreventionofAMD 2m Thin ean Patientorpopulation:generalpopulation Cd ocm Settings:community hraine Intervention:vitaminE neral Comparison:placebo Cs ollaboupplem Outcomes Illustrativecomparativerisks* (95%CI) Relativeeffect Noofparticipants Qualityoftheevidence Comments ration.entsfo (95%CI) (studies) (GRADE) Pr ublishpreve Assumedrisk Correspondingrisk edbntin Placebo Antioxidant supple- yg mentation Johage nWiley-related AnyAMD 180per1000 1(18519pteor210040)0 RR0.97(0.85to1.09) 4(40),887 ⊕hi⊕gh⊕⊕ &m Sa oncu AdvancedAMD 6per1000 8per1000 RR1.34(0.84to2.14) 40,887 ⊕⊕⊕⊕ s,Ltdlarde (5to13) (4) high .g e n er *The basis for the assumedrisk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95%confidence interval) is a tio basedontheassumedriskinthecomparisongroupandtherelativeeffectof theintervention(andits95%CI). n (R AMD:age-relatedmaculardegeneration;CI:confidenceinterval;RR:riskratio e v ie w GRADEWorkingGroupgradesof evidence ) Highquality:Furtherresearchisveryunlikelytochangeourconfidenceintheestimateof effect. Moderatequality:Furtherresearchislikelytohaveanimportantimpactonourconfidenceintheestimateof effectandmaychangetheestimate. Lowquality:Furtherresearchisverylikelytohaveanimportantimpactonourconfidenceintheestimateof effectandislikelytochangetheestimate. Verylowquality:Weareveryuncertainabouttheestimate. 3 BACKGROUND Whyitisimportanttodothisreview Antioxidantvitaminandmineralsupplementsareincreasinglybe- ingmarketedforuseinage-relatedeyedisease,includingAMD. Descriptionofthecondition Theaimofthisreviewwastoexaminetheevidenceastowhetheror nottakingvitaminormineralsupplementspreventsthedevelop- Age-relatedmaculardegeneration(AMD)isadiseaseaffectingthe mentofAMD.SeealsotherelatedCochranereview’Antioxidant centralareaoftheretina(macula).Intheearlystagesofthedis- vitaminandmineralsupplementsforslowingtheprogressionof easelipidmaterialaccumulatesindepositsunderneaththeretinal AMD’whichconsiderswhethersupplementationforpeoplewith pigmentepithelium.Thesedepositsareknownasdrusen,andcan AMDslowsdowntheprogressionofthedisease(Evans2006). beseenaspaleyellowspotsontheretina.Thepigmentofthereti- nalpigmentepitheliummaybecomedisturbed,withareasofhy- perpigmentationandhypopigmentation.Inthelaterstagesofthe disease,theretinalpigmentepitheliummayatrophycompletely. OBJECTIVES Thislosscanoccurinsmallfocalareasorcanbewidespread(ge- ographic).Insomecases,newbloodvesselsgrowunderthereti- To determine whetherantioxidant vitamin and/or mineral sup- nalpigmentepitheliumandoccasionallyintothesubretinalspace plementationpreventsthedevelopmentofAMD. (exudativeorneovascular).Haemorrhagecanoccurwhichoften resultsinincreasedscarringoftheretina. Theearlystagesofthediseaseareingeneralasymptomatic.Inthe METHODS laterstagestheremaybeconsiderabledistortionwithinthecentral visualfieldleadingtoacompletelossofcentralvisualfunction. Population-basedstudiessuggestthat,inpeople65yearsandolder, Criteriaforconsideringstudiesforthisreview approximately5%haveadvancedAMD(Owen2012).Itisthe mostcommoncauseofblindnessandvisualimpairmentinindus- trialisedcountries.IntheUKforexample,over30,000peopleare Typesofstudies registeredasblindorpartiallysightedannually,halfofwhomhave Weincludedrandomisedcontrolledtrials(RCTs)comparingan- losttheirvisionduetomaculardegeneration(Bunce2006). tioxidant vitamin and/or mineral supplementation (alone or in combination)tocontrol. Descriptionoftheintervention Typesofparticipants Photoreceptorsintheretinaaresubjecttooxidativestressthrough- Participants in the trialswere people in the general population, out life due to combined exposures to light and oxygen. It has withorwithoutdiseasesotherthanAMD.Weexcludedtrialsin beenproposedthatantioxidantsmaypreventcellulardamagein whichtheparticipantswereexclusivelypeoplewithAMD.These theretinabyreactingwithfreeradicalsproducedintheprocessof trialsareconsideredinaseparateCochranereviewexaminingthe lightabsorption(Christen1996). effect of supplementation on progression of the disease (Evans Thereareanumberofnon-experimentalstudiesthathaveexam- 2006). inedthepossibleassociationbetweenantioxidantmicronutrients andAMD,althoughfewstudieshaveexaminedsupplementation specifically(Chong2007;Evans2001).Dataonvitamin intake Typesofinterventions inobservationalstudiesshouldbeconsideredcautiouslyaspeople Antioxidants were defined as any vitamin or mineral which is whohaveadietrichinantioxidantvitaminsandminerals,orwho knowntohaveantioxidantpropertiesinvivoorwhichisknown choosetotakesupplementsregularly,aredifferentinmanyways tobeanimportantcomponentofanantioxidantenzymepresent fromthosewhodonot;thesedifferencesmaynotbeadequately intheretina.Weconsideredthefollowing:vitaminC,vitaminE, controlledbystatisticalanalysis.Theresultsoftheseobservational carotenoids(includingthemaculapigmentcarotenoidsluteinand studieshavebeeninconclusive. zeaxanthin),seleniumandzinc. Typesofoutcomemeasures Howtheinterventionmightwork Thefollowingoutcomeswereused: The underlying theory is that antioxidant vitamin and mineral 1. numberofparticipantsdevelopingAMD; supplementswillprotecttheretinaagainstoxidativestressandthat 2. numberofparticipantswithvisuallossduetoAMD; thisprotectionwilldelaytheonsetofAMD. 3. qualityoflifemeasures; Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 4 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. 4. anyadverseoutcomesreported. Selectionofstudies Weusedthefollowingdefinitions: Ourinitialsearchesidentifiedalltrialsofantioxidantsupplements AMD:thiswastakenasdefinedbytrialinvestigators.Itiscom- and therefore generated many citations. Each review author as- monly defined as: in the macular area 3000 microns diameter sessedhalfofthetitlesandabstractsresultingfromthesearches fromfovea:drusenwithorwithoutpigmentaryabnormalitiesor andselectedstudiesaccording tothedefinitions inthe’Criteria geographicatrophyorcharacteristicchoroidalneovascularisation forconsideringstudiesforthisreview’.Tocheckthatwewerecon- withnoothercause.Wherepossible, wehaveusedtheAge-Re- sistent,webothassessedasubsetof100recordsandcomparedre- latedEyeDiseaseStudySystemforclassifyingage-relatedmacular sults.Weobtainedfullcopiesofallreportsreferringtocontrolled degeneration(AREDS2001b).Inparticular,theterm’advanced trialsthatdefinitelyorpotentiallymettheinclusioncriteria.We AMD’referstogeographicatrophyorneovascularAMD. assessedthefullcopiesandselectedstudiesaccording tothein- Visualloss:anywell-definedoutcomebasedonvisualacuitywas clusioncriteria.Wewrotetoauthorsoftrialsforwhichtherewere useddependingonthewayinwhichauthorspresentedtrialdata. no published outcome data on AMD to ask whether they had Quality of life: any validated measurement scale which aims to collectedanydataoneyediseaseoutcomes. measure the impact of visual function loss on quality of life of Asnoneofthetrialsrespondedpositively,i.e.gaveusunpublished participants. dataonAMD,forfurtherupdatesofthisreviewweonlyconsid- eredtrialswithpublisheddataonAMD. Inupdatestothisreview,bothauthorswentthroughthetitlesand Searchmethodsforidentificationofstudies abstractsresultingfromthesearchesindependentlyandresolved disagreementsbydiscussion. Electronicsearches Dataextractionandmanagement We searched the Cochrane Central Register of Controlled Tri- We extracted data using methods forms developed by the als (CENTRAL) 2011, Issue 12, part of The Cochrane Library. Cochrane Eyes and Vision Group (http://eyes.cochrane.org/ www.thecochranelibrary.com(accessed26January2012),MED- resources-review-authors).Weextracteddataindependentlyand LINE(January1950toJanuary2012),EMBASE(January1980 resolveddisagreementsbydiscussion.Oneauthorcutandpasted toJanuary 2012), OpenGrey(SystemforInformation onGrey thedatainto RevMan 5(Review Manager 2011)andtheother Literature in Europe) (www.opengrey.eu/), the metaRegister of authorcheckedthatthishadbeendonecorrectly. ControlledTrials(mRCT)(www.controlled-trials.com),Clinical- Trials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/ Assessmentofriskofbiasinincludedstudies search/en). There were no language or date restrictions in the searchfortrials.Theelectronicdatabaseswerelastsearchedon26 Two authors independently assessed risk of bias using the January2012. CochraneCollaboration’stoolforassessingriskofbiasasdescribed See: Appendices for details of search strategies for CENTRAL inChapter8oftheCochraneHandbookforSystematicReviewsof (Appendix1),MEDLINE(Appendix2),EMBASE(Appendix3), Interventions(Higgins 2011).Weresolveddisagreementsbydis- OpenGrey(Appendix5),mRCT(Appendix6),ClinicalTrials.gov cussion.Wecontactedtrialauthorsforclarificationonanyparam- (Appendix7)andtheICTRP(Appendix8). etergradedas’unclear’.Thereviewauthorswerenotmaskedto Fortheupdatein2012wespecificallylookedforadverseeffects anytrialdetails. usingasimplesearchaimedtoidentifysystematicreviewsofad- verseeffectsofvitaminsupplements,seeAppendix(Appendix9) Measuresoftreatmenteffect forsearchstrategy. Ourmeasureoftreatmenteffectwastheriskratiofordichotomous outcomesandthemeandifferenceforcontinuousoutcomes.Cur- Searchingotherresources rentlythereviewonlyincludesanalysisofdichotomousoutcomes. WesearchedtheScienceCitationIndexandthereferencelistsof reportsoftrialsthatwereselectedforinclusion.Wecontactedthe Unitofanalysisissues investigatorsofincludedandexcludedtrialstoaskiftheyknewof anyotherrelevantpublishedorunpublishedtrials. Theinterventions,bydefinition,areappliedtothepersonbutas mostpeoplehavetwoeyestrialscananalysedatafromoneorboth eyes.Thetrialsincludedinthisreviewreportedthedevelopment ofAMDineithereyeofthepersonthereforetheunitofanalysis Datacollectionandanalysis wasthesameastheunitofrandomisation. Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 5 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. Assessmentofheterogeneity Theoriginal searchstrategyinvolvedidentifyingalltrialsofan- Weassessedheterogeneitybyvisualinspectionoftheforestplot, tioxidant interventions and asking trialists if they had collected theχ2testforheterogeneityandtheI2statistic. dataonAMD.Wewrotetotheauthorsof60trialsofantioxidant interventions in people with diseases other than AMD. We re- ceived15responsesandnonehadcollectedanyrelevantdata.All Datasynthesis 60trialsareshownintheexcludedstudiessectionofthisreview. Wesummariseddatausingtheriskratio,aftertestingforhetero- Asthisprovedtobeaninefficientwayofidentifyingrelevanttri- geneitybetweentrialresultsusingastandardChi2test. als,subsequentsearchesincludedtermsforAMD.Threehundred andsixty-sevenreportsoftrialswerefoundinMay2002,343in May 2005 and64reportsinJanuary 2006 butnofurthertrials Subgroupanalysisandinvestigationofheterogeneity wereidentifiedthatwererelevantforinclusioninthisreview.The Nosubgroupanalyseswereplanned.Onlyfourtrialsareincluded resultsofthePHSIstudywerepublishedin2007. atpresentwhichmeansthatitisnotpossibletoinvestigatehet- ThesearcheswererepeatedinAugust2007inwhichatotalof129 erogeneityformally. reportsofstudieswereidentified.TheTrialsSearchCo-ordinator (TSC)scannedthesearchresultsandremoved84referenceswhich werenotrelevanttothescopeofthereview.Wescreenedthetitle Sensitivityanalysis andabstractsoftheremaining45referencesandobtainedfull-text Weplannedtoconductsensitivityanalysestodeterminetheim- copiesoffourreportstoassessforpotentialinclusioninthereview. pactofstudyqualityoneffectsize.Currentlytherearefourhigh- WeidentifiedonenewreportfromthePHSIstudytobeincluded qualitytrialsincludedinthereviewandthereforethisisnotrele- inthereviewandthethreeremainingstudieswereexcluded.For vantatpresent. reasonsofexclusion,see’Characteristicsofexcludedstudies’table. Anupdate searchwas done inJanuary 2012 whichyielded477 titlesandabstracts. TheTSCscannedthesearchresultsandre- moved206referenceswhichwerenotrelevanttothescopeofthe RESULTS review.Wescreenedthetitleandabstractsoftheremaining271 references.Werejected267abstractsasnoteligibleforinclusion inthereview.Weobtainedfull-textcopiesoffourreportsforfur- Descriptionofstudies therexamination.OnenewreportfromtheWHSstudyhasbeen includedinthereviewandthreeotherstudieswereexcluded.For reasonsofexclusion,see’Characteristicsofexcludedstudies’table. Resultsofthesearch Theinitialsearchesresultedin3178titlesandabstracts.Ofthese, Includedstudies 208werereportsofpotentiallyeligibletrialreports.Fromthesere- Seethe’Characteristicsofincludedstudies’tableformoredetailed portsweidentifiedsevenprimarypreventiontrialsofantioxidant information. vitaminormineralsupplements(ATBC1994;CARET;deKlerk 1998; LINXIAN; Nambour 1995; PHS I; WHS). Investigators from three trials have confirmed that they did not collect data Typesofparticipants onAMD(CARET;deKlerk1998;Nambour1995).Thesetrials ThestudiestookplaceinAustralia,USAandFinland.Twostudies havebeenexcludedfromthereview.Wedidnotreceivearesponse recruited men only (ATBC 1994; PHS I), one study recruited fromonetrial(LINXIAN)andthistrialhasbeenexcluded.Three women only (WHS) and one study recruited men and women trialshavepublisheddataonAMDoutcomes(ATBC1994;PHS (VECAT).Peopletakingpartinthetrialswereidentifiedfromthe I;WHS)andareincludedinthisreview.SearchoftheNational general population. Participants in PHS I were male physicians EyeInstituteClinicalResearchregisteridentifiedonefurtheron- and in WHS were female health professionals. In ATBC 1994, goingtrialwhichiscollectinginformationonAMD-theWomen’s arandomsampleof1035menaged65yearsorabovefromthe AntioxidantCardiovascularStudy(WACS).Therearetwotrials mainstudywereinvitedtoparticipatewitharesponserateof91% thathaverecruitedparticipantswithandwithoutAMD(AREDS; (941men).InVECAT,18%hadAMDatbaseline. VECAT).VECATisincludedinthisreviewbecause82%ofpar- ticipantsdidnothavesignsofAMD.AREDSisnotincludedin Typesofintervention thisreviewbecauseAMDoutcomesforpeoplewithoutAMDat baselinewerenotreported;itisincludedintheCochranereview In ATBC 1994, the groups receivedeither alpha-tocopherol 50 examining the effect of supplementation on progression of the mg per day alone, beta-carotene 20 mg per day alone, alpha- disease(Evans2006). tocopherol and beta-carotene or placebo. All formulations were Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 6 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. coloured with quinoline yellow. Treatment duration was five to wasgained tocontact theirophthalmologistor optometristand eightyears(median6.1years).InVECAT,participantswereran- furtherdetailswereobtainedfromthemedicalrecords. domisedtovitaminE(500IUaday)orplacebo.Supplementation InVECAT,photographsweretakenwithaNidek3-DXfundus continued for four years. In PHS I, the groups received aspirin camera on Kodachrome 64 ASA colour film. The photographs 325mgeveryotherday,beta-carotene50mgeveryotherday,as- were graded at baseline independently by two trained graders. pirinandbeta-caroteneorplacebo.Treatmentdurationaveraged EarlyAMD(theprimaryoutcome)wasdefinedassoftdrusen(dis- 12 years. In WHS, participants receivedvitamin E (600 IU on tinctorindistinct)orpigmentarychanges(hyperpigmentationor alternatedays)orplaceboandwerefollowedupfor10years. hypopigmentation)onphotographicgrading.Onclinicalgrading thiswaslarge/softdrusenornon-geographicalretinalpigmentep- itheliumatrophy.VECATusedBailey-Lovievisualacuitycharts Typesofoutcomemeasures #4and#5(NationalVisionResearchInstitute,Australia). InATBC 1994,threephotographs ofeach eyeweretaken with a Canon fundus camera at 40 and 60 degree angles on Kodak Excludedstudies Ektachrome100ASAslidefilm.Thesephotographsweregraded Seethe’Characteristicsofexcludedstudies’tableforfurtherin- byoneobservermaskedtotheparticipant’streatmentgroup.The formation. following grades of maculopathy were used: 0 = none; I = dry maculopathywithharddrusenand/orpigmentarychanges;II= softmaculardrusen;III=disciformdegeneration;IV=geographic Riskofbiasinincludedstudies atrophy. InPHSIandWHS,AMDwasascertainedbyselfreport:“Have Weconsidered allfour trialstobe atlowrisk ofbias (Figure 1; youeverhadmaculardegenerationdiagnosedinyourrightorleft Figure 2). See ’Risk of bias’ tables for each included study for eye?”.Iftheparticipantansweredyestothisquestionpermission detailsoftheassessment. Figure1. ’Riskofbias’graph:reviewauthors’judgementsabouteachriskofbiasitempresentedas percentagesacrossallincludedstudies. Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 7 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd. Figure2. ’Riskofbias’summary:reviewauthors’judgementsabouteachriskofbiasitemforeachincluded study. Antioxidantvitaminandmineralsupplementsforpreventingage-relatedmaculardegeneration(Review) 8 Copyright©2012TheCochraneCollaboration.PublishedbyJohnWiley&Sons,Ltd.

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In WHS, participants received vitamin E (600 IU on alternate days) or placebo and were followed up for 10 years. Types of outcome measures. In ATBC 1994, three photographs of each eye were taken with a Canon fundus camera at 40 and 60 degree angles on Kodak. Ektachrome 100 ASA slide film.
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