the girasoles (sunflower) study: exploring the physiologic heat … · 2018. 11. 7. · the...
TRANSCRIPT
TheGirasoles(Sunflower)Study:ExploringthePhysiologicHeatStressResponse
LindaMcCauley,RN,PhD,FAAN,FAAOHNDeanandProfessor
NellHodgsonWoodruffSchoolofNursingEmoryUniversity
Friday,October26,2018
TheGirasoles(Sunflower)Study
CenterforDiseaseControlandPrevention|NationalInstituteforOccupationalSafetyandHealth2014-18R01-OH01657-01
OccupationalHeatStress
TheMoultrieObserver
NaplesDailyNews
1. Hazard2. Vulnerabilityfactors:
• Workplaceexposure• Sensitivity(non-modifiable)• Adaptivecapacity(modifiable)
3. HeatStressResponse
FarmworkerVulnerabilitytoHeatHazardsFramework
Mac,ValerieViThien,andLindaA.McCauley."Farmworkervulnerabilitytoheathazards:aconceptualframework."Journalofnursingscholarship49.6(2017):617-624.
5GirasolesStudyRecruitmentLocationsinFlorida Pierson
ApopkaFellsmereImmokaleeHomestead
RecommendedCoreBodyTemperatureLimits
38.0°C(100.4°F)–Forworkersnotacclimatizedormedicallycleared.38.5°C(101.3°F)–Forworkersacclimatized,medicallyscreenedandmonitored.Workercorebodytemperatureshouldneverexceedthislevel.
3WorkdaysofBiomonitoring+SurveysBaseline,Pre-WorkdayandPost-WorkdayBiologicalSamples:- UrineSpecificGravity- Bloodosmolality/Bloodchemistry
Survey:- Heat-relatedIllness
Symptoms- Demographics
ComprehensiveHeatStressMonitoringActigraphAccelerometerrecordsphysicalactivity
Heartratemonitormeasuresheartrateatwork
CorTemp®monitorrecordscorebodytemperature
Homemonitorrecordstheovernighthometemperatures
iButtonrecordsthetemperatureandhumidityatyourworkplace
Hazard:EnvironmentalHeatStress
EnvironmentalHeat• FAWNData:
• RegionalWeatherNetworkDataevery15minutes• MeanHeatIndex:90°F±6
• iButtonData• Immokalee(n=66)andApopka(n=39)• 284Observationdays• Worksite-baseddataevery15minutes=10,000readings• MeanHeatIndex:105°F±9.2
MacVV,HertzbergV,McCauleyLA.ExaminingAgriculturalWorkplaceMicroandMacroclimateDataUsingDecisionTreeAnalysistoDetermineHeatIllnessRisk.JournalofOccupationalandEnvironmentalMedicine,inpress,October2018.
Vulnerability
StudyParticipantCharacteristicsn=248
• MeanAge:38years(SD±9)• Female:62%• YearsinU.S.Agriculture:12years(SD±8)• CountryofOrigin:Mexico(66%),Guatemala(15%),Haiti(10%),Other(7%),U.S.(2%)
• WorkType:Crops(31%),Fernery(26%)andNursery(41%)
MeasuredWorkActivity:Accelerometer• Accelerometerwasplacedattheworker’srightiliaccrestand
recordedaccelerationcountsonthreeplanesofmotion(vertical,antero-posterior,andmedio-lateral)every30secondsduringtheworkday
• Vectormagnitude(VM3):acompositeactivitycountmeasureincorporatingallthreeplanesofmotion
• Timespentinmoderatetovigorousactivity(MV):calculatedbysummingtheminutesreachingaVM3countof≥26901
1SasakiJE,JohnD,FreedsonPS.ValidationandcomparisonofActiGraphactivitymonitors.JSciMedSport.2011;14(5):411-6.doi:10.1016/j.jsams.2011.04.003.PubMedPMID:21616714.
ActivityMeasuresfromAccelerometerData
ProportionofDaySpentinActivityLevels
ActivityPatternOvertheWorkday
HydrationStatus• Urinesamplescollectedbeforeworkandafterworkfromeachparticipant
• UrineSpecificGravity(USG):measurementwidelyusedtomeasurehydrationstatusinthefieldsetting– Valuesrangefrom1.000(purewater)to1.050(maximumconcentrationcapacityofrenalsystem
• USGwascategorizedinto– USG≥1.020:hypohydrationthreshold– USG≥1.030:clinicalindicatorforseveredehydration
USGmeasuresbeforeandafterwork
PlotsdisplayUSGmeasuresforn=248workers,over549workdays
HydrationStatus(n=248,549workdays)
Biomarker Before Work1 After Work1
p value2
USG, mean ± SE 1.020 ± 0.0004 1.024 ± 0.0004 <.0001
USG ≥ 1.020 53% 81% <.0001
USG > 1.030 3% 13% <.0001
1nparticipantsforday1wasn=248,day2wasn=243,andday3wasn=2282adjustedforrandomeffectsduetomultipleparticipantsinhouseholdsandmultipledaysperparticipant
Mix,J.,Elon,L.,ViThienMac,V.,Flocks,J.,Economos,E.,Tovar-Aguilar,A.J.,StoverHertzberg,V.andMcCauley,L.A.,2018.HydrationStatus,KidneyFunction,andKidneyInjuryinFloridaAgriculturalWorkers.Journalofoccupationalandenvironmentalmedicine,60(5),pp.e253-e260.
Response
HeatRelatedIllnessSymptoms• Onthepost-worksurvey,workersreportedHRIsymptomsexperiencedduringtheirworkday:– Excessivesweating– Headache– Dizziness– Nausea/Vomiting– MuscleCramps– Confusion– Fainting
• 84.3%ofworkersreportedatleastonesymptom,42.3%reportedtwoormoresymptoms,and18.6%reportedthreeormore
Heat-RelatedIllnessSymptomsDuringWork
71%
42%
19% 15% 14% 9% 5%EXCESSIVESWEATING
HEADACHE DIZZINESS NAUSEAORVOMITING
MUSCLECRAMPS
CONFUSION FAINTING
Mutic,A.D.,Mix,J.M.,Elon,L.,Mutic,N.J.,Economos,J.,Flocks,J.,Tovar-Aguilar,A.J.andMcCauley,L.A.,2018.ClassificationofHeat-RelatedIllnessSymptomsAmongFloridaFarmworkers.Journalofnursingscholarship,50(1),pp.74-82.
BodyTemperature&HeartRateinOneWorker- Recordedevery30seconds- 2consecutivereadingsover38.0Cor38.5Cconsideredexceedingphysiologiclimitthreshold
- TemperatureorHeartRatefileremovedif>20%ofdatapointsmissing
MethodsforAnalyzingReal-TimeData
CoreTemperatures2015-2017
82%reached38.0°CLengthoftimeover38.0°CMedian=69minutesRange=1-555minutes
24%reached38.5°CLengthoftimeover38.5°CMedian=22minutesRange=1-318minutes
HeartRate2015-2017%WorkerswithaMeanWorkdayHeartRate(HR)>115bpm
(35%ofMaximumAerobicCapacity)on≥1StudyDay0
20
40
60
80
100
MeanHR≥115bpm
MeanHR<115bpm
79.4%
20.6%
WhatVulnerabilityFactorsPredicttheHeatResponse?
• HydrationStatus• WorkIntensity• Gender,Age,BMI• MedicalConditions• BreaksandShade
PhysiologicResponsetoHeat:CoreTemperature>=38°C
SignificantRiskFactors: ChangeinoddsofT≥38 95%CI
ModelconsideredWorkIntensity Per10MinutesMod/VigActivity 5%increase 2%-8%Per1unitBMI 7%increase 1%-13%Per5°FMeanHeatIndex 27%increase 4%-56% ModelconsideredDehydration Per.010UrineSpecificGravityinpm 47% increase 8%-101%Per1unitBMI 6%increase 1%-12%Per5°FMeanHeatIndex 26%increase 3%-54%
PhysiologicResponsetoHeat:CoreTemperature>=38.5°C
SignificantRiskFactors:
ChangeinoddsofT≥38.5 95%CIModelconsideredWorkIntensity Per10MinutesMod/VigActivity 4%increase 0%-7%Per1yearWorkinginAgriculture 8% decrease (-13)%-(-3)%Per1unitBMI 17%increase 7%-27%Per5°FMeanHeatIndex 39%increase 2%-89%Male(comparedtoFemale) 142% increase 20%-386%ModelconsideredDehydration DehydrationwasnotasignificantpredictorofT≥38.5;otherresultssimilar
HeatExposureandKidneyFunction
KidneyFunction:2015-2016Biomarker Before Work1 After Work1
p value2
Serum Creatinine, mean 0.70 ± 0.13 0.80 ± 0.013 <.0001
eGFR, mean 115.2 ± 0.94 104.7 ± 0.94 <.0001
eGFR <90 3% 20% <.0001
BUN, mean 14.4 ± 0.29 15.8 ± 0.29 <.0001
Serum Potassium, mean 4.4 ± 0.02 4.2 ± 0.02 <.0001
Serum Sodium, mean 141.0 ± 0.11 141.2 ± 0.11 .01 1nparticipantsforday1wasn=248,day2wasn=243,andday3wasn=2282adjustedforrandomeffectsduetomultipleparticipantsinhouseholdsandmultipledaysperparticipant
ChronicKidneyDiseaseofUnknownEtiology(CKDu)
• Affecting agricultural workers around the globe • Mainly sugar cane industry • Primarily young men in seemingly good health • Need for dialysis in 30’s and 40’s • > 20,000 premature deaths in Central America alone • California Heat Illness Prevention Study (CHIPS) (n=295)
– 12% with acute kidney injury over the course of one day at work
AKIinGirasolesPresenceofAKI:• 36%ofparticipantshadthecriteriaindicatingAKIonatleastoneworkdayStagesofAKI:• 32%hadstage1AKIonatleastoneworkday• 3%hadstage2AKIonatleastoneworkday• 0.4%hadstage3AKIonatleastoneworkday• TheoddsofAKIincreased22%foreach5bpmincreaseinmeanheartrateand37%foreach
5degree(°F)increaseinmeanheatindex(KIDIGOCriteria:Increaseofpost-shiftserumcreatininebyatleast0.3mg/dLOR≥1.5timesthepre-shiftcreatinine)
Analyses/PapersinProgress• PredictorsforHeatStressSymptomsandCoreBodyTemperatures
• OverallHealthStatusandWorkBehaviorsasPredictorsofHeatResponse
• QuantifyingOccupationalWorkIntensityandHeatStressResponse
• SeasonalDifferencesinWorkIntensityandHeatStressResponse
****CommunityTranslationofResearchFindings*****
NextSteps
• Pilottestinginterventionstoreduceheatrelatedillness• Metabolomicanalysisofworkerswithheatexposure• Heatexposureandthemicrobiome
Acknowledgements• FarmworkersAssociationofFlorida
– JeannieEconomos– AntonioTovar-Aguilar,PhD– NezahualcoyotlXiuhtecutli,MS
• UniversityofFlorida– JoanFlocks,JD
• EmoryUniversity– RoxanaChicas,BSN,RN– LisaElon,MS– VickiHertzberg,PhD,FASA,P.Stat– ValerieMac,PhD,RN– JacquelineMix,PhD,MPH– AbbyMutic,MSN– NathanMutic,MS,MAT,M.Ed– EstefaniIgnacio,BS
• Funders– NIOSHR01OH010657– NIOSHR21OH009830-01
Thankyou!