Noise induced hearing loss: An occupational medicine ... · noise-induced hearing loss represents a...
Transcript of Noise induced hearing loss: An occupational medicine ... · noise-induced hearing loss represents a...
Noiseinducedhearingloss:AnoccupationalmedicineperspectiveEmilyZ.StuckenMDMichiganEarInstituteRobertS.HongMD,PhDMichiganEarInstituteCorrespondingauthor:RobertS.HongMD,PhDMichiganEarInstitute30055NorthwesternHighway,Suite#101FarmingtonHills,MI48334Phone(248)865-4444AbstractPurposeofreview:Upto30millionworkersintheUnitedStatesareexposedtopotentiallydetrimentallevelsofnoise.Whilereliablemedicationsforminimizingorreversingnoiseinducedhearingloss(NIHL)arenotcurrentlyavailable,NIHLisentirelypreventable.ThepurposeofthisarticleistoreviewtheepidemiologyandpathophysiologyofoccupationalNIHL.Wewillfocusonat-riskpopulationsanddiscusspreventionprograms.Currentpreventionprogramsfocusonreductionofinnereardamagebyminimizingenvironmentalnoiseproductionandthroughtheuseofpersonalhearingprotectivedevices.Recentfindings:Noiseinducedhearinglossistheresultofacomplexinteractionbetweenenvironmentalfactorsandpatientfactors,bothgeneticandacquired.Theeffectsofnoiseexposurearespecifictoanindividual.Trialsarecurrentlyunderwayevaluatingtheroleofantioxidantsinprotectionfrom,andevenreversalof,NIHL.Summary:OccupationalNIHListhemostprevalentoccupationaldiseaseintheUnitedStates.Occupationalnoiseexposuresmaycontributetotemporaryorpermanentthresholdshifts,thougheventemporarythresholdshiftsmaypredisposeanindividualtoeventualpermanenthearingloss.Noisepreventionprogramsareparamountinreducinghearinglossasaresultofoccupationalexposures.Keywords:occupationalnoiseinducedhearingloss,occupationalnoiseexposure,hearingprotectionprograms
IntroductionHearinglossisthemostwidespreaddisabilityinWesternizedsociety.Noiseexposureisthemostcommonpreventablecauseofhearingloss;someestimatethatonethirdofallcasesofhearinglosscanbeattributedtonoiseexposure.1Occupationalexposuretonoisemakesupagreatproportionofpatientsaffectedbynoiseinducedhearingloss(NIHL),makingNIHLthemostprevalentoccupationaldiseaseintheUnitedStates.2Occupationalnoiseexposurehasbeendocumentedsinceatleastthe18thcentury,whenitwasnotedthatcopperminersdevelopedhearinglossasaresultofthenoisefromhammeringonmetal.3ScopeoftheproblemWorldwide,1.3billionpeopleareaffectedbyhearingloss.4Itisestimatedthat10%oftheworld’spopulationareatriskforNIHL.2WithintheUnitedStates,16-24%ofhearinglossescanbeattributedtooccupationalnoiseexposures.5,6Infact,itisestimatedthat22millionto30millionworkersintheUnitedStatesareexposedtopotentiallydetrimentallevelsofnoise.2,7Theeffectsofoccupationalnoiseexposureplaceatremendousburdenonboththeindividualandsociety.Thefinancialburdentosocietyissignificantandcontinuestorise,withanestimated$242.4millionannualexpenditureincompensationforwork-relatedhearinglossintheUnitedStates.2Followingmilitaryservice,workersaffectedbyNIHLmakeupthemostpopulateddisabilityclassification.In2010,theU.S.DepartmentofVeteransAffairscompensatedmorethan1.4millionveteransforservice-connectedNIHLandtinnitus,resultinginmorethan$1.2billionofcompensation.3WorkersmostatriskforoccupationalNIHLincludethoseemployedinconstruction,manufacturing,mining,agriculture,utilities,transportation,andthemilitary,aswellasmusicians.Aretrospectivecohortstudyevaluatedaudiogramsof1millionemployeesexposedtoloudnoiseandfoundthejobsathighestriskforhearinglossweremining,woodproductmanufacturing,constructionofbuildings,andrealestateandrentalleasing.Withinthisgroupof1millionnoise-exposedworkers,hearinglosswasmoreprevalentamongmenthanwomen,andtheriskofhearinglossincreasedwithage.8TheconsequencesofoccupationalNIHLtotheindividualcanbedire.Hearinglosslimitsanindividual’sabilitytocommunicatewiththesurroundingworld,whichcanleadtoincreasedsocialstress,depression,embarrassment,poorself-esteem,andrelationshipdifficulties.Obstaclesincommunicationareexacerbatedbydifficultlisteningsituationssuchasenvironmentswithexcessivebackgroundnoise.Hearinglosscanaffectattentionandcognition.2Inolderadults,amildhearinglossisassociatedwithatwotimesincreasedriskofdementia,whileaseverehearinglossisassociatedwithafivetimesincreasedriskofdementia.9Associatedauralfullnessandtinnituscanalsobeextremelytroublesomeforsomepeople.
OccupationalNIHLhasbeenassociatedwithanincreasedriskforwork-relatedinjuries.Excessivenoisehamperstheabilitytohearwarningsignals,monitorequipment,respondtoenvironmentalsounds,andcommunicatewithotherworkers.Onestudyof46,550workersexposedtonoisefoundastatisticallysignificantincreaseinriskforinjuryrequiringhospitalizationwitheachdecibelofhearingloss.Thehazardratioforinjurywas1.01foreachdecibelofhearingloss.10Anotherstudyevaluated1,062workersinatractormanufacturingplant.Inthisstudy,workersexposedtosoundintensities>85dBAaveragedover8hourshada1.52foldincreasedriskofinjurycomparedtoworkersexposedto<85dBA.11Undiagnosedhearinglosshasbeenassociatedwithanexcessmortalityof10-20%overthecourseof20years.12Noise-inducedhearinglosshasalsobeenassociatedwithanumberofnon-auditorysequelae.Themostprevalentoftheseareannoyance,cognitiveimpairment,sleepdisturbance,andadversecardiovascularhealth.2Atheoryhasbeenproposedthatnoiseexposureleadstostimulationoftheautonomicnervoussystemandendocrinesystem,leadingtoincreasedstresshormonereleaseandelevationsinbloodpressureandheartrate.This,inturn,mayleadtoanincreasedriskofhypertension,ischemicheartdisease,andstroke.13,14Epidemiologicalstudieshavedemonstratedahigherprevalenceofcardiovasculardiseaseandmortalityinpopulationsexposedtohighnoiselevels.15,16,17,18,19,20,21PathophysiologyNoiseinducedhearinglossmaybeinflictedbyshortburstsofloudsoundorcontinuouslyelevatednoiselevels.2Suchexposuresleadtocochlearhaircelldamage,damagetosurroundingsupportingcells,andultimatelydegenerationofassociatedauditorynervefibers.Thelevelofinnereardamageandassociatedhearinglossarecorrelatedtotheintensityanddurationofnoiseexposure.3Sublethallevelsofnoisedamagemayleadclinicallytotemporarythresholdshifts,inwhichanindividualexperiencesdepressedsensorineuralhearingthatusuallyrecoverswithin24to48hours.Moreseveredamageleadstoapermanentthresholdshift,clinicallymanifestedasanirreversibledecreaseinhearingthresholds.Recentevidencesuggeststhateventemporarythresholdshiftsfromwhichanindividualrecoversarenotinnocuous,assuchinsultsmayacceleratetheprocessofage-relatedhearingloss.22,23,24Theamountofhearinglossinflictedbyaspecifiednoiseexposureisvariableandspecifictoanindividual.Likemanydiseaseprocesses,thepathophysiologyofnoise-inducedhearinglossrepresentsacomplexinteractionbetweengeneticandenvironmentalfactors.Someauthorshaveestimatedthatupto50%ofindividualvariationsinhearinglossduetonoiseexposuremaybeattributedtohereditaryfactors.25Inaddition,otherpatient-relatedfactorssuchasage,pre-existingsensorineuralhearingloss,hypertension,diabetesmellitus,smokinghistory,and
useofototoxicmedicationsmayaltertheamountofdamageincurredtotheinnerearasaresultofnoise.1Noiseexposuretypicallyaffectsthehaircellsnearthebasalturnofthecochlea,leadingtoacharacteristicdecreaseinhearingthresholdsbetween3kHzand6kHz.Thispatternofhearinglosswillproduceadistinctivedipat4kHzonpure-toneaudiometry,oftentermedthe“noisenotch”(Figure1).Thenaturalresonancefrequenciesoftheouterear,inparticulartheearcanal,appeartoemphasizethedamagetothisfrequencyregion.Thelowerfrequencies,includingthemainspeechfrequencies,areoftensparedinitially.Withprogressivedamage,however,thenoisenotchwillflattenasthresholdsdecreaseatthesurroundingfrequencies.3Individualswithseverehearinglossasaresultofnoiseexposuremayhaveaudiogramsthatareindistinguishablefromothercausesofhearingloss.OccupationalNIHListypicallybilateralandsymmetric.Theremaybe,however,someasymmetryinhearingloss,particularlyifthereisdifferentialexposuretosoundbetweenthetwoears.Whenadiscrepancyispresent,occupationalNIHLiscommonlymoresevereintheleftear,thoughthereasonsforthishavenotbeenscientificallybornout.3Somehavehypothesizedthataright-handedmachineoperatormaybemorelikelytolookovertheirrightshoulder,leavingtheleftearturnedtowardamachineengine.Inhuntersorotherswhoshootfirearms,hearinglosstendstobemoresevereintheearclosesttothebarrelofthegun;theoppositeearisrelativelyprotectedbytheheadshadoweffect.Musiciansmayhavediscrepanciesbasedontheirlocationwithinthebandororchestra.Brassplayersgenerallyproducethegreatestamountofnoise,26andmusiciansseatedwithonesideclosertoanoise-producinginstrumentmayhavegreaterexposureinthatear.PreventionProgramsAtthepresenttime,occupationalNIHLisnotatreatabledisease.Itis,however,entirelypreventable.Afocusisplaced,therefore,onpreventionofNIHLbeforepermanentdamagetotheinnerearcanoccur.Preventionstrategiesmaybefocusedonreducingnoiselevelsinanoccupationalenvironmentoronreducingtheamountofenvironmentalnoisethatistransmittedtoanindividual’sinnerearsystem.Manycountrieshaveimplementedlegalstandardsregardingoccupationalnoiseexposureandtheneedforprotectionaboveacertainexposurelevel.IntheUnitedStates,occupationalnoiseexposureisregulatedbytheOccupationalSafetyandHealthAdministration(OSHA,adivisionoftheU.S.DepartmentofLabor)andtheNationalInstituteforOccupationalSafetyandHealth(NIOSH,adivisionoftheU.S.CentersforDiseaseControlandPreventionwithintheU.S.DepartmentofHealthandHumanServices).ThesetwogoverningbodiesworktogethertodevelopandenforceworkplacesafetyregulationsinthepreventionofoccupationalNIHL.Inordertomonitoroccupationalnoiseexposures,noiselevelsmustbequantifiedandexpressedasanumericalvaluethatcanbesubjectedtostandardizedregulations.Forregulatorypurposes,noiselevelsaregenerallymeasuredinthe
dBAscaleandexpressedasan8-hourtime-weightedaverage(TWA).ThedBAscaleisadecibelscaleinwhichthelowfrequenciesarerelativelyde-emphasized.Thisscaleisappliedwhenmeasuringoccupationalnoiseexposurebecausehigh-frequencynoiseexposurescausegreaterthresholdshiftsthanlow-frequencyexposuresofequivalentintensity.27OSHAandNIOSHhavebothsetforthregulatoryguidelinesforacceptableoccupationalnoiseexposuresandrecommendationsforhearingconservationprograms.OSHAregulationscarrytheweightoflaw;however,NIOSHrecommendationsaremorestringentandarethoughttobebackedbystrongerscientificevidence.27UnderOSHAcriteria,themaximum8-hournoiseexposureis90dBA.Fornoiseabove90dBA,exposuretimemustbereducedby50%forevery5dBincrease(e.g.maximumallowableexposuretimefor95dBAnoiseis4hours,etc.).Thisisreferredtoasthe5-dBtradingruleor5-dBexchangerate.Incontrast,NIOSHrecommendationsarecalculatedusinga3-dBexchangerate,inwhichexposuretimemustbehalvedforevery3dBelevationinnoiselevels.Inaddition,NIOSHsetstherecommended8-hourTWAexposureat85dBAratherthan90dBA.27Thesechangesleadtoconsiderablymoreprotectiveregulationsforworkers,asisdemonstratedinTable1.OSHAmandatesthatahearingconservationprogrambeprovidedforworkerswhoareexposedtonoise>85dBoveran8-hourTWA.Thishearingconservationprogrammustincludethefollowingelements:(1)employersmustmeasurenoiselevelsonthepremises,(2)freehearingprotectivedevicesmustbeprovidedifnoiseexceedsexposurelimits,(3)employeesmustbetrainedregardingnoiseexposureandtheuseofpersonalhearingprotectivedevices,(4)employeesmustbeprovidedwithbaselineandannualaudiogramstoassesstheirhearing,and(5)recordsofalltestresultsmustbekeptandmadeavailabletoemployees.27Withregardtonoiseregulation,noisesourcesortheenvironmentmustbealteredasmuchaspossiblethroughengineeringorschedulingchangestodecreasenoiselevelsintheworkplace.28Mechanismstoreducenoiseproductionandexposurethroughengineeringandadministrativecontrolsmayprovidethemosteffectivemeansforreducingworkers’exposuretonoise,butoftenthesemechanismsareunrealisticorimpossibletoimpose.Whentheon-the-jobenvironmentalnoiselevelscannotbebroughtdowntoacceptablestandards,everyemployeemustbeprovidedwithappropriatepersonalhearingprotectivedevicesandinstructedontheiruse.Itmaybethatcurrentregulations,whicharebaseduponrecoveryofpure-tonethresholdsfollowingnoiseexposure,will,inthefuture,needtotakeintoaccounttherecentlyreportedfindingsthatevenrecoveryofthresholdsfollowingtemporarythresholdshiftsdoesnottrulyindicateanundamagedear.22,23,24Personalhearingprotectivedevicesincludebothearmuffsandearplugs.Expandablefoamplugsprovidesimilarnoiseattenuationtoearmuffs,thoughothertypesofearplugsprovidelessprotection.Advertisedattenuationlevelsofhearingprotectivedevicesrangefrom15-28dBwhentestedinalaboratorysetting.Inrealworkplaceconditions,mostearmuffsandexpandablefoamplugswillprovide10to15dBattenuation.Theuseofearmuffsandplugstogetherimprovesattenuationby5to10dBovereitherdevicealone.Aprotectiveeffectof10to15dBisrelevanttoa
noise-exposedworker,as10dBofattenuationwillbringnoiselevelsintotheacceptablerangeinmorethan90%ofexposedworkers.27Datahasshownthatearplugsmaynotprovidetheadvertisedlevelofprotectionifemployeesarenotinstructedontheirproperuse.29ThemostimportantvariableinpreventingoccupationalNIHLwithpersonalhearingprotectivedevicesisconsistentuseofthedevice.DatasuggestthatpersonalhearingprotectivedevicesareeffectiveinpreventingNIHL;29,30,31,32however,studieshavedemonstratedthatmanyworkersdonotregularlyusethesedevices.33,34,35,36,37Non-useofhearingprotectivedevicestendstobemoreprevalentincertainoccupations,particularlyamongagriculturalworkers.38Musiciansrepresentanotherclassofworkersmanyofwhomdonotregularlyusehearingprotectivedevices.26Studiesevaluatingthesuccessofhearingprotectionprogramshavedemonstratedconflictingresults.ACochraneReviewof15studiesincluding79,986participantsfoundthattheregularuseofpersonalhearingprotectivedevicesaspartofastronghearinglosspreventionprogramwasassociatedwithlesshearingloss.29Otherstudieshavedemonstratedsignificantcontinuedhearinglosseveninthepresenceofahearinglosspreventionprogram.Groenewoldandcolleaguesstudiedaudiometricdatafrom19,911workerswhowereexposedtosignificantnoise,stratifiedintogroupsbasedonsurveyresponsesintothoseworkerswhoneverusedhearingprotectionandthosewhoalwaysusedhearingprotection.DatadidnotshowanysignificantdifferenceinOSHAthresholdshiftsbetweenthetwogroups,thoughtherewasasignificanttrendtowardincreasedriskforhighfrequencythresholdshiftwithoutuseofprotectivedevices.39FutureDirectionsResearchintotheunderlyingdiseaseprocesseshasproducedsomeheadwayinachievingpreventativeandtherapeutictreatmentsforoccupationalNIHL.SeveralauthorshavetheorizedthatoxidativestressplaysaroleinthepathogenesisofNIHLonamicrocellularlevel.40,41Accordingly,severalantioxidantcompoundshavebeenexploredfortheirprotectiveproperties.Inastudylookingatthetreatmenteffectoftheantioxidantcompoundmagnesiumafterimpulsenoise,magnesium-treatedguineapigshadimprovedhaircellpreservationcomparedtogroupstreatedwithmethylprednisoloneandwithplacebo.42Theantioxidantprecursorofglutathione,N-acetyl-L-cysteine,hasbeenshowntohaveprotectiveeffectsagainstnoiseexposureinchinchillastudies.43Humanstudiesonsuchcompoundsarepreliminaryandhavehadconflictingresults.Onetrialinwhich31normal-hearingparticipantsweretreatedwithN-acetylcysteineasaprotectivemechanismagainstnightclubmusicexposuredidnotdemonstrateaprotectiveeffect.44Adouble-blind,placebo-controlledcrossoverstudy,however,performedon53noise-exposedworkersdiddemonstratethatN-acetylcysteinesignificantlyreducedtheincidenceoftemporarythresholdshift.45Interestingly,variabilityinresponsetothiscompoundwasassociatedwithgenetic
polymorphisms.ThoseworkerswiththeglutathioneStransferasesnullgenotypedemonstratedincreasedresponsestothetreatmentcompound.Anothercompound,D-methionine,maysoonundergoclinicaltrialswiththeUSArmyforitsuseasanotoprotectiveagent.26D-methionineisaningredientofyogurtandcheesethathasshownaprotectiveeffectagainstNIHLinanimalstudies.46,47Thisagentwaseffectiveevenwhenadministeredafterthenoiseexposure.EachofthesecompoundshasshownpromiseinpreventingorreversingtheeffectsofNIHL,andhopefullyinthefuturewilladdtothearmamentariumofprotectivetoolsagainstoccupationalNIHL.ConclusionOccupationalNIHListhemostprevalentoccupationaldiseaseintheUnitedStates.Theburdenofdiseaseiffeltbyboththeaffectedindividualandbysociety.Treatmentstrategiesareinthedevelopmentalstages;beforetheybecomeuniversallyavailable,themainstayofcareisinprevention.PreventionprogramstoreduceoccupationalNIHLcanbeeffective,buttheyrequirecompliancewithOSHAandNIOSHstandardsandconsistentuseofpersonalhearingprotectivedevices.
KeyPoints- OccupationalNIHListhemostprevalentoccupationaldiseaseintheUnited
States.- OccupationalNIHLcanresultinpsychosocialisolationandanincreasedrisk
ofdementiaintheelderlypopulation,aswellasanincreasedriskofinjury,heartdisease,andstroke.
- Theeffectsofnoiseonanindividual’shearingthresholdaredependentonacomplexinteractionbetweengeneticandenvironmentalfactorsthatisuniquetoanindividual.
- ThemostimportantwaytomitigateoccupationalNIHListhroughpreventionprogramsthatemphasizeexposurereductionsandtheuseofpersonalhearingprotectivedevices.
- AntioxidantcompoundshaveshownpromiseaspreventativeandpossibletherapeuticagentsagainstNIHL.
MaximumExposureDurationMaximumExposureLevelindBA
OSHAHCA(1983)Regulations
NIOSH(1998)Recommendations
85 8hours88 4hours90 8hours 2hours,31minutes95 4hours 47minutes,37seconds97 3hours 30minutes100 2hours 15minutes105 1hour 4minutes,43seconds110 30minutes 1minute,29seconds115 15minutesorless 28secondsTable1.ComparisonofOSHAandNIOSHregulationsfornoiseexposure.
Figure1.Pure-toneaudiogramdemonstratingtheclassic“noisenotch”at4kHz.
References1NationalInstitutesofHealth.ConsensusDevelopmentConferenceStatement:NoiseandHearingLoss.Bethesda,MD;U.S.DepartmentofHealth&HumanServices;1990.2BasnerM,BabischW,DavisA,etal.Auditoryandnon-auditoryeffectsofnoiseonhealth.Lancet2014;383:1325-32.**Adetaileddiscussionoftheeffectsofnoiseinducedhearinglossandtheirimplicationsforpublichealth.3HongO,KerrM,PolingG,DharS.Understandingandpreventingnoise-inducedhearingloss.DisMon2013;59:110-8.**Anexcellentreviewofthemechanismsandeffectsofnoiseinducedhearingloss,aswellaspreventionprograms.4VosT,FlaxmanAD,NaghaviM,etal.Yearslivedwithdisability(YLDs)for1160sequelaeof289diseasesandinjuries1990-2010:asystematicanalysisfortheGlobalBurdenofDiseaseStudy2010.Lancet2012;380:2163-96.5NelsonDI,NelsonRY,Concha-BarrientosM,FingerhutM.Theglobalburdenofoccupationalnoise-inducedhearingloss.AmJIndMed2005;48:446-58.6TakS,CalvertGM.Hearingdifficultyattributabletoemploymentbyindustryandoccupation:AnanalysisoftheNationalHealthInterviewSurvey–UnitedStates,1997to2003.JOccupEnvironMed2008;50:46-56.7NationalInstituteforOccupationalSafetyandHealth(NIOSH).NationalOccupationalResearchAgenda.Cincinnati,OH:NationalInstituteofOccupationalSafetyandHealthPublications1996.96-115.8MastersonEA,TakS,ThemannCL,etal.PrevalenceofhearinglossintheUnitedStatesbyindustry.AmJIndMed2013;56:670-81.9LinFR.Hearinglossinolderadults:who’slistening?JAMA2012;307:1147-8.10GirardSA,LerouxT,CourteauM,PicardM,TurcotteF,RicherO.Occupationalnoiseexposureandnoise-inducedhearinglossareassociatedwithwork-relatedinjuriesleadingtoadmissiontohospital.InjPrev2014;Epubaheadofprint.11Amjad-SardrudiH,DormohammadiA,GolmohammadiR,PoorolajalJ.Effectofnoiseexposureonoccupationalinjuries:Across-sectionalstudy.JResHealthSci2012;12:101-4.12KarpaMJ,GopinathB,BeathK,etal.Associationsbetweenhearingimpairmentandmortalityriskinolderpersons:theBlueMountainsHearingStudy.AnnEpidemiol2010;20:452-9.13BabischW.Cardiovasculareffectsofnoise.In:NriaguJ0,ed.Encyclopediaofenvironmentalhealth.Burlington:Elsevier,2011:532-42.14LuskS,GillespieB,HagertyBM,ZiembaRA.Acuteeffectsofnoiseonbloodpressureandheartrate.ArchEnvironHealth2004;59:392-99.15VanKempenEE,KruizeH,BoshuizenHC,AmelingCB,StaatsenBA,deHollanderAE.Theassociationbetweennoiseexposureandbloodpressureinischemicheartdisease:ameta-analysis.EnvironHealthPerspect2002;110:307-17.
16TomeiG,FioravantiM,CerrattiD,etal.Occupationalexposuretonoiseandthecardiovascularsystem:ameta-analysis.SciTotalEnviron2010;408:681-89.17DaviesH,vanKampIV.Noiseandcardiovasculardisease:areviewoftheliterature2008-2011.NoiseHealth2012;14:287-91.18HussA,SpoerriA,EggerM,RoosliM,fortheSwissNationalCohortStudyGroup.Aircraftnoise,airpollution,andmortalityfrommyocardialinfarction.Epidemiology2010;21:829-36.19SorensenM,HvidbergM,AndersenZJ,etal.Roadtrafficnoiseandstroke:aprospectivecohortstudy.EurHeartJ2011;32:737-44.20GanWQ,DaviesHW,KoehoornM,BrauerM.Associationoflong-termexposuretocommunitynoiseandtraffic-relatedairpollutionwithcoronaryheartdiseasemortality.AmJEpidemiol2012;175:898-906.21SorensenM,AndersenZJ,NordsborgRB,etal.Roadtrafficnoiseandincidentmyocardialinfarction:aprospectivecohortstudy.PLoSOne2012;7:e39283.22KujawaSG,LibermanMC.Accelerationofage-relatedhearinglossbyearlynoiseexposure:evidenceofamisspentyouth.JNeurosci2006;26:2115-23.23CampoP,VenetT,RumeauC,etal.Impactofnoiseorstyreneexposureonthekineticsofpresbycusis.HearRes2011;280:122-32.24KujawaSG,LibermanMC.Addinginsulttoinjury:cochlearnervedegenerationafter“temporary”noise-inducedhearingloss.JNeurosci2009;29:14077-85.25Sliwinska-KowalskaM.Contributionofgeneticfactorstonoise-inducedhearingloss.In:GriefahnB,ed.10thinternationalcongressonnoiseasapublichealthproblemoftheinternationalcommissiononbiologicaleffectsofnoise,London,UK,2011.http://www.icben.org/proceedings.html(accessedApril25,2014).26Sliwinska-KowalskaM,DavisA.Noise-inducedhearingloss.NoiseHealth2012;14:274-80.27Gelfand,SA.Theeffectsofnoiseandindustrialaudiology.In:EssentialsofAudiology,NewYork:Thieme,2001.33;501-541.28U.S.DepartmentofLabor(USDL),OccupationalSafetyandHealthAdministration(OSHA).Occupationalnoiseexposure:hearingconservationamendment;finalrule.FedRegist1983;48:9738-85.29VerbeekJH,KatemanE,MorataTC,DreschlerWA,MischkeC.Interventionstopreventoccupationalnoise-inducedhearingloss.CochraneDatabaseSystRev2012.*Athoroughevidence-basedreviewoftheefficacyandutilityofpreventionprogramsforoccupationalhearingloss.30HongO.HearinglossamongoperatingengineersinAmericanconstructionindustry.IntArchOccupEnvironHealth2005;78:565-574.31BrinkLI,TalbottEO,BurksJA,PalmerCV.Changesovertimeinaudiometricthresholdsinagroupofautomobilestampingandassemblyworkerswithahearingconservationprogram.AmIndHygAssocJ2002;63:482-7.32HesselPA.HearinglossamongconstructionworkersinEdmonton,Alberta,Canada.JOccupEnvironMed2000;42:57-63.33NeitzelR,SeixasN.Theeffectivenessofhearingprotectionamongconstructionworkers.JOccupEnvironHyg2005;2:227-38.
34HongO,RonisDL,LuskSL,KeeGS.Efficacyofacomputer-basedhearingtestandtailoredhearingprotectionintervention.IntJBehavMed2006;13:304-14.35KerrMJ,SavikK,MonsenKA,LuskSL.Effectivenessofcomputer-basedtailoringversustargetingtopromoteuseofhearingprotection.CanJNursRes2007;39:80-97.36McCullaghM,LuskSL,RonisDL.Factorsinfluencinguseofhearingprotectionamongfarmers:atestofthependerhealthpromotionmodel.NursRes2002;51:33-39.37HongO,ChinDL,RonisDL.PredictorsofhearingprotectionbehavioramongfirefightersintheUnitedStates.IntJBehavMed2013;20:121-30.38DepczynskiJ,ChallinorK,FragarL.ChangesinthehearingstatusandnoiseinjurypreventionpracticesofAustralianfarmersfrom1994to2008.JAgromed2011;16:127-42.39GroenewoldMR,MastersonEA,ThemannCL,DavisRR.Dohearingprotectorsprotecthearing?AmJIndMed2014.Epubaheadofprint.40LePrellCG,DolanDF,BennettDC,BoxerPA.Nutrientplasmalevelsachievedduringtreatmentthatreducesnoise-inducedhearingloss.TranslRes2011;158:54-70.41LePrellCG,SpankovichC.Healthydietsanddietarysupplements:recentchangesinhowwemightthinkabouthearingconservation.In:GriefahnB,ed.10thInternationalCongressonNoiseasaPublicHealthProblemoftheInternationalCommissiononBiologicalEffectsofNoise,London,UK,2011.http://www.icben.org/proceedings.html(accessedApril25,2014).42AbaamraneL,RaffinF,GalM,AvanP,SendowskiI.Long-termadministrationofmagnesiumafteracoustictraumacausedbygunshotnoiseinguineapigs.HearRes2009;247:137-45.43KopkeRD,JacksonRL,ColemanJK,LiuJ,BielefeldEC,BaloughBJ.NACfornoise:Fromthebenchtoptotheclinic.HearRes2007;226:114-25.44KramerS,DreisbachL,LockwoodJ,etal.EfficacyoftheantioxidantN-acetylcysteine(NAC)inprotectingearsexposedtoloudmusic.JAmAcadAudiol2006;17:265-78.45LinCY,WuJL,ShihTS,etal.N-acetylcysteineagainstnoise-inducedtemporarythresholdshiftinmaleworkers.HearRes2010;269:42-7.46SamsonJ,Wiktorek-SmagurA,PolitanskiPetal.Noise-inducedtime-dependentchangesinoxidativestressinthemousecochleaandattenuationbyd-methionine.Neuroscience2008;152:146-50.47CampbellK,ClaussenA,MeechR,VerhulstS,FoxD,HughesL.d-methionine(d-met)significantlyrescuesnoise-inducedhearingloss:Timingstudies.HearRes2011;282:138-44.