Role of maternal health and infant inflammation in nutritional and neurodevelopmental outcomes of

20 Pages·2017·1.85 MB·English

RESEARCHARTICLE
Role of maternal health and infant
inflammation in nutritional and
neurodevelopmental outcomes of two-year-
old Bangladeshi children
JeffreyR.Donowitz1,2,HeatherCook3,MasudAlam4,FahmidaTofail5,MamunKabir4,E.
RossColgate6,MaryaP.Carmolli6,BethD.Kirkpatrick6,CharlesA.Nelson7,8,Jennie
Z.Ma9,RashidulHaque4,WilliamA.Petri,Jr.1*
a1111111111
a1111111111 1 DivisionofInfectiousDiseasesandInternationalHealth,UniversityofVirginia,Charlottesville,Virginia,
UnitedStatesofAmerica,2 DivisionofPediatricInfectiousDiseases,Children’sHospitalofRichmondat
a1111111111
VirginiaCommonwealthUniversity,Richmond,Virginia,UnitedStatesofAmerica,3 DepartmentofStatistics,
a1111111111
UniversityofVirginia,Charlottesville,Virginia,UnitedStatesofAmerica,4 DivisionofParasitology,
a1111111111 InternationalCentreforDiarrhoealDiseaseResearch,Bangladesh,(icddr,b),Dhaka,Bangladesh,5 Child
DevelopmentUnit,InternationalCentreforDiarrhoealDiseaseResearch,Bangladesh,(icddr,b),Dhaka,
Bangladesh,6 DepartmentofMedicine,UniversityofVermontCollegeofMedicine,Burlington,Vermont,
UnitedStatesofAmerica,7 DivisionofDevelopmentalMedicine,BostonChildren’sHospital,Harvard
MedicalSchool,Boston,Massachusetts,UnitedStatesofAmerica,8 HarvardGraduateSchoolofEducation,
Boston,Massachusetts,UnitedStatesofAmerica,9 DepartmentofPublicHealthSciences,Universityof
OPENACCESS Virginia,Charlottesville,Virginia,UnitedStatesofAmerica
Citation:DonowitzJR,CookH,AlamM,TofailF,
*[e-mail]
KabirM,ColgateER,etal.(2018)Roleofmaternal
healthandinfantinflammationinnutritionaland
neurodevelopmentaloutcomesoftwo-year-old
Bangladeshichildren.PLoSNeglTropDis12(5): Abstract
e0006363.https://doi.org/10.1371/journal.
pntd.0006363
Background
Editor:ZulfiqarA.Bhutta,TheHospitalforSick
Children,CANADA
Previousstudieshaveshownmaternal,inflammatory,andsocioeconomicvariablestobe
Received:September8,2017 associatedwithgrowthandneurodevelopmentinchildrenfromlow-incomecountries.How-
Accepted:March4,2018 ever,theseoutcomesaremultifactorialandworkdescribingwhichpredictorsmoststrongly
influencethemislacking.
Published:May29,2018
Copyright:©2018Donowitzetal.Thisisanopen
Methodology/Principalfindings
accessarticledistributedunderthetermsofthe
CreativeCommonsAttributionLicense,which WeconductedalongitudinalstudyofBangladeshichildrenfrombirthtotwoyearstoassess
permitsunrestricteduse,distribution,and
oralvaccineefficacy.Variablespertainingtomaternalandperinatalhealth,socioeconomic
reproductioninanymedium,providedtheoriginal
status,earlychildhoodentericandsystemicinflammation,andanthropometrywerecol-
authorandsourcearecredited.
lected.Bayley-IIIneurodevelopmentalassessmentwasconductedattwoyears.Asasec-
DataAvailabilityStatement:Thedatausedused
ondaryanalysis,weemployedhierarchicalclusterandrandomforeststechniquestoidentify
inthisanalysisisavailableinSupporting
InformationfilesS1–S3Datasets. andrankwhichvariablespredictedgrowthandneurodevelopment.Clusteranalysisdemon-
stratedthreedistinctgroupsofpredictors.Mother’sweightandlength-for-ageZscore(LAZ)
Funding:Thisworkwassupportedbyagrantsto
WPfromtheBill&MelindaGatesFoundation atenrollmentwerethestrongestpredictorsofLAZattwoyears.CognitivescoreonBayley-
(https://www.gatesfoundation.org)andfromNIH IIIwasstronglypredictedbyweight-for-age(WAZ)atenrollment,income,andLAZatenroll-
(https://www.niaid.nih.gov/;R01AI043596)andto
ment.ToppredictorsoflanguageincludedRotavirusvaccination,plasmaIL5,sCD14,
JRDfromthePediatricScientistDevelopment
TNFα,mother’sweight,andmalegender.Motorfunctionwasbestpredictedbyfecalcalpro-
Program(https://www.cincinnatichildrens.org/
education/research/psdp;5K12HD000850).The tectin,WAZatenrollment,fecalneopterin,andplasmaCRPindex.Thestrongestpredictors
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
fundershadnoroleinstudydesign,datacollection forsocial-emotionalscoreincludedplasmasCD14,income,WAZatenrollment,andLAZat
andanalysis,decisiontopublish,orpreparationof enrollment.Basedontherandomforests’predictions,theestimatedpercentageofvariation
themanuscript.
explainedwas35.4%forLAZattwoyears,34.3%forΔLAZ,42.7%forcognitivescore,
Competinginterests:Theauthorshavedeclared 28.1%forlanguage,40.8%formotor,and37.9%forsocial-emotionalscore.
thatnocompetinginterestsexist.
Conclusions/Significance
Birthanthropometryandmaternalweightwerestrongpredictorsofgrowthwhileentericand
systemicinflammationhadstrongerassociationswithneurodevelopment.Birthanthropom-
etrywasapowerfulpredictorforalloutcomes.Thesedatasuggestthatfurtherstudyof
stuntinginlow-incomesettingsshouldincludevariablesrelatingtomaternalandprenatal
health,whileinvestigationsfocusingonneurodevelopmentaloutcomesshouldadditionally
targetcausesofsystemicandentericinflammation.
Authorsummary
Childrenfromlow-incomesettingsexperiencelineargrowthfalteringandneurodevelop-
mentaldelaythathavebeenassociatedwithmaternal,socioeconomic,andinfectious/
inflammatoryvariables.Giventheinterdependentnatureoftheseassociations,under-
standingwhichvariablesarethebestpredictorsofpooroutcomeshasbeendifficult.We
conductedalongitudinalstudyofBangladeshichildrenfrombirthtotwoyearsandcol-
lectedpredictorsassessingmaternal,inflammatory,andsocioeconomicaspectsofearly
childhoodinBangladeshichildren.Weconductedarandomforestsanalysistorankpre-
dictorsassociatedwithgrowthandneurodevelopment.Lineargrowthwasbestpredicted
bybirthanthropometryandmaternalweight.Cognitivefunctionwaspredictedbybirth
anthropometry,socioeconomicstatus,andsystemicinflammation.Thereceiptofthe
rotavirusvaccineandacombinationofsystemicinflammatory,maternal,andsocioeco-
nomicvariablespredictedlanguagescore.Motorscorewaspredictedbysystemic
inflammationwithentericinflammatorymarkershavingareverserelationship.Social-
emotionaldevelopmentwaspredictedbysystemicinflammation,birthanthropometry,
andeconomicmeans.Thisworkdemonstratesthatspecificpathwaysareresponsiblefor
differentaspectsofgrowthanddevelopment.Ourdatasuggestthatstudiesinvestigating
pediatricstuntinginlow-incomesettingsshouldfocusonmaternalandprenatalvariables
whilethosefocusedonneurodevelopmentaloutcomesshouldadditionallytargetcausesof
systemicandentericinflammation.
Introduction
159millionchildrenunderfiveyearsold,or23.8%oftheworld’spopulationinthisagerange,
arestunted(length-for-ageZscore[LAZ]<-2standarddeviations[SD])[1].Inapooled
analysis,stuntingconferredahazardratioof2.28formortalitypriortofiveyearsofagewith
severestunting(LAZ<-3SD)havingahazardratioof5.48[2].Ithasalsobeensuggestedthat
growthdeficitsearlyinlifeleadtoobesity,typeIIdiabetes,andmetabolicdisturbanceslaterin
life[3].Heighthasbeenpositivelyassociatedwithearningssuggestingthatearlylifeadversity
affectinggrowthleadstoanimmenselossof“humancapital”throughoutmuchoftheworld
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
[4].Additionally,stuntingandinfectionhavebeenassociatedwithneurodevelopmentaldefi-
cits,compoundingthelosstoproductivity[3].
Bothgrowthandneurodevelopmentaremultifactorial,whichmakesdesigningeffective
interventionsdifficult,especiallyinlow-andmiddle-incomecountries(LMICs)wherea
varietyofinterconnectedinsultsarepresent.Systemicinflammation,febrileepisodes,lackof
primaryvaccines,lowersocioeconomicstatus,andpoorsanitationhaveallbeendirectly
associatedwithstuntinginchildrenfromLMICs[5–11].Environmentalentericdysfunction
(EED),hallmarkedbyentericinflammation,hasalsobeenshowntobeassociatedwith
deficitsinlineargrowth[6,12–14].Importantly,EEDhasbeenidentifiedasadistinct
entityfromdiarrhealdiseasealthoughpathogencarriagemayplayaroleinitsdevelopment
[15–18].
Inadditiontopostnatalfactorssuchasnutritionandinflammation,prenatalandmaternal
factorshavealsobeencorrelatedwithgrowth.Maternalanthropometricsandmaternaleduca-
tionhavebothbeenassociatedwithstuntinginchildrenlivinginLMICs[7,9,19,20].Ina
multinationalstudy,a1cmincreaseinmaternalheightwasassociatedwitha1.2%decreasein
riskofchildmortality[21].Additionally,birthanthropometryisastrongpredictorofpostna-
talgrowthsuggestingprenatalinsultseffectstunting[6,9].
AssociationsbetweenaspectsofchildhoodlifeinLMICsandneurodevelopmentalout-
comeshavealsobeendescribed.Lowerneurodevelopmentalscoreshavebeenassociatedwith
diarrhealdiseaseinsomestudies[22–24]butnotinothers[25].Theeffectofentericinfection
onneurodevelopmentmaybepathogen-specificasdeficitshavebeenassociatedwithgiardiasis
andcryptosporidiosisspecifically[23,26].Earlychildhoodsystemicinflammationandfebrile
illnesshavealsobeenassociatedwithpoorneurodevelopmentaloutcomes[27,28].Onapopu-
lationlevel,averagenationalIQwasassociatedwithoverallburdenofinfectiousdiseasessug-
gestinganinflammatorypathwaymediatingeffectsonneurodevelopment[29].Additionally,
stuntinghasbeenassociatedwithpoorneurodevelopmentaloutcomesalthoughthenatureof
thisrelationshipremainsundefined[3,30–33].
Differenttypesofinsultsaffectseparateaspectsofneurodevelopment[34].Prenataland
maternalfactorsincludingmaternalmalnutritionhavebeenassociatedwithdecreasedprob-
lemsolvingandmotorfunction[35,36].Earlylifeanthropometricshavebeenassociatedwith
cognitiveandlanguagefunction[34].Inonestudybreastfeedingwasassociatedwithimproved
languageskillsbutnotsocial-emotional/behavioralskills[37].Neonatalsepsishasbeenlinked
todecreasedmotorandcognitivefunctionbutnotsocial-emotionalfunction[38,39].Sys-
temicinflammationinanimalmodelsandincreasedintestinalpermeabilityinhumanshas
beenlinkedtosocial-emotionalfunction[40,41].Thecombinationofthesefindingssuggesta
needtoassessneurodevelopmentdirectlyandwithsubscaleanalysis.
Manyofthevariablesassociatedwithpoorgrowthandneurodevelopmentarenotindepen-
dentbutratherinterdependent[42,43].Thishasmadeanalysisoftheirindividualimportance
intheseoutcomesdifficult.OurobjectivewastoclarifywhichaspectsofchildhoodinLMICs
arethestrongestpredictorsofbothgrowthandneurodevelopment.
Methods
WeconductedalongitudinalstudyfrombirthtotwoyearsinBangladeshiinfantsandcol-
lecteddataassessingmaternalhealth,socioeconomicstatus,sanitaryconditions,andenteric
andsystemicinflammationinearlychildhood.Weutilizedrandomforestsanalysis,anensem-
blemachinelearningmethod,toidentifyandrankpredictorsoflineargrowthandneurodeve-
lopment.Thepredictabilityoftopvariablesfromrandomforestswasestimatedfromalinear
modelandexpressedasthepercentageofvariation.Tovalidateourfindings,thesamesetof
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
predictivevariablesusedforrandomforestswerealsoanalyzedinapenalizedlinearmodel
withsmoothlyclippedabsolutedeviation(SCAD)penalty.
Studydesign
ThePerformanceofRotavirusandOralPolioVaccinesinDevelopingCountries(PROVIDE)
studyisalongitudinalstudyofBangladeshiinfants.TheprimaryobjectiveofthePROVIDE
studywastodetermineiftherewasanassociationbetweenEEDandtheunderperformanceof
oralvaccineswiththeanalysisdescribedherebeingsecondary.Detailedmethodsofthisstudy
havebeenpublishedelsewhere[6,44].Briefly,700childrenwereenrolledwithinoneweekof
birth.ParticipantswererandomizedtoreceivetheRotarixoralrotavirusvaccineornotandall
childrenreceivedtheoralpoliovaccine.ArollingadmissionspannedfromMay2011through
November2014.ResultsofthisstudyexaminingtheassociationofbiomarkersofEEDand
oralpoliovaccinefailure,rotavirusvaccinefailure,growththroughoneyearofage,smallintes-
tinebacterialovergrowth,theimpactofenteropathogensonoralrotavirusandpoliovaccina-
tion,andtheassociationofRotarixvaccinationandserumzinclevelswithsevererotavirus
diarrheahavebeenpublishedelsewhere[6,45–47].
Studypopulation
PROVIDEwasconductedintheurbanboroughofMirpurinDhaka,Bangladesh.Theareais
denselypopulatedwithameanof5peoplelivingin1.5rooms.Over95%oftheconstructionis
oftinormudbrick.Uncoveredsewerdrainsflowthroughouttheareaandabut59%ofdwell-
ings.OursubjectstendedtocomefromthelowersocioeconomicstrataofMirpurduetothe
areainwhichrecruitmentoccurredandthelocationofourstudyclinic.
Rotavirusvaccination
Allchildrenreceivedvaccines,administeredbythestudystaff,includedintheBangladesh
ExpandedProgrammeonImmunization,includingtheoralpoliovaccine.Childrenwereran-
domizedafterenrollmenttoreceivetheoralrotavirusvaccineRotarix(GlaxoSmithKlineplc.,
Middlesex,UK)ornot.ChildrenrandomizedtotheRotarixvaccinearmreceivedtwodosesat
10and17weeksofage.Rotavirusvaccinationwasassessedasadichotomouspredictor,either
receivingthevaccineornot.
Biomarker,socioeconomic,anthropometric,andBayleyassessments
Stoolandserumforbiomarkeranalysiswascollectedwithin7daysofthescheduledstudyvisit
andwereimmediatelystoredat4˚C.SamplesweretransportedfromourfieldofficetoThe
InternationalCentreforDiarrhoealDiseaseResearch,BangladeshParasitologyLaboratory
andstoredat-80˚Cwithin4hoursofcollection.Theywerethenpulledandanalyzedin
batches.
Plasmaactivin,plasmaferritin,plasmaanti-lipopolysaccharide(LPS)antibody,plasmareti-
nolbindingprotein(RBP),plasmasolubleclusterdesignation14(sCD14),plasmazinc,fecal
myeloperoxidase,fecalcalprotectin,fecalalpha-1antitrypsin,fecalneopterin,fecalReg1B,
plasmavitaminD,plasmaC-reactiveprotein(CRP),andCytomegalovirus(CMV)statuswere
assessedviacommerciallyavailableELISAkits.CMVstatuswasdichotomizedtopositiveor
negativepermanufacturer’sspecifications(Abcam,inc.Cambridge,MaUSA).Mannitol
recoverywasassessedviaurinehighperformanceliquidchromatographyaftergivingchildren
astandardizedmannitolload.Plasmacytokineanalysiswasconductedviaacommercially
availableHumanBioPlexProassay[6,44].
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Plasmaactivin,plasmacytokines,andplasmaCRPwerechosenasmarkersofsystemic
inflammation.Plasmaferritin,RBP,andzincwerechosenasbothacutephasereactantsand
keynutritionalvariables.VitaminDwasalsoselectedasakeynutritionalmeasure.Fecalmye-
loperoxidase,fecalcalprotectin,fecalalpha-1antitrypsin,fecalneopterin,andfecalReg1B
wereselectedasmarkersofentericinflammationanddamage.Mannitolrecovery,anti-LPS
Ab,andsCD14wereselectedasmarkersofintestinalpermeability.
Diarrhealsurveillancetocalculatedaysofdiarrheawasconductedbyfieldresearchassis-
tantswhovisitedthehomesoftheparticipantstwiceperweek.Maternalandsocioeconomic
datawerecollectedatthetimeofenrollmentviaquestionnaire.Mother’slevelofeducation
achievedwascollectedthendichotomizedtoanyformaleducationornoformaleducation.
Presenceofanopendraindirectlyoutsidethehome,family’suseofaseptictankortoilet(as
opposedtoslablatrines,pitlatrines,openlatrine,hanginglatrines,oropendefecation),useof
atoiletsharedbyotherfamilies,anduseofanymethodofimprovedwatertreatmentwerealso
assessedviaquestionnaire.Anthropometricassessment(includingmaternalanthropometry)
wasconductedbystudyphysicianstrainedintheprocedureusingmeasuringboards,measur-
ingtape,andcalibratedscalesasappropriateforsizeandage.Anthropometrywasmeasuredat
enrollmentandat16scheduledstudyvisitsthroughoutthe2-yearstudyperiod.
Atrainedpsychologistassessedneurodevelopmentalscoresattwoyearsofageusingaver-
sionoftheBayleyScalesofInfantandToddlerDevelopment,ThirdEdition(Bayley-III)that
wasadaptedtobeculturallyappropriatetoBangladeshichildren.Despiteculturaladaptation,
thisversionwasnotnormalizedtotheBangladeshipopulation.ThisversionoftheBayleyIII
hasbeenusedinotherstudiesbyourgroupandwasshowntohavehighshortterm(within7
days)retestreliability(r>0.80)andhighinter-observerreliability(r=0.99)[27,28].
Statisticalanalysis
LAZ,weight-for-ageZscore(WAZ),andweight-for-heightZscore(WHZ)werecalculated
usingtheWorldHealthOrganizationsoftwareWHOAnthro(version3.2.2).CRPwasmea-
suredat4timepoints(6,18,40,and53weeks).Thevariable“CRPindex”wascreatedasa
measureofsustainedinflammation.Foreachmeasurement,ifachildwasinthetop50thper-
centileforthattimepoint,theyweregivenascoreof1.“CRPIndex”wascreatedbysumming
thescoresgivenforallfourCRPmeasurementsandthusrangedfrom0to4.Cytokineswere
discretizedinto<50thpercentile,the50th–75thpercentile,and>75thpercentile.Allothervari-
ableswereeitherdichotomousorcontinuousbasedonthenatureofthevariables.
Separatedatasetswerecreatedforanthropometricandneurodevelopmentaloutcomes.Any
childwithanincompletedatasetforthespecifiedoutcomewasremovedfromtheanalysis.
Outliersinpredictors,definedasanyvalue>5SDfromthemean,wereexcludedfromthe
analysis.28subjectsforanthropometricanalysisand22subjectsforneurodevelopmental
analysiswereexcluded.Outlierswerenotassessedinoutcomemeasurements.Differencesin
enrollmentcharacteristicsbetweentheremainingsubjectsandtheoriginalcohortwhohad
completeenrollmentdatawereassessedviaMann-WhitneyUtestsandχ2testsasappropriate.
Pearsoncorrelationforallpredictivevariableswascalculatedusingthedatasetconstructed
foranthropometry.Hierarchicalclusteringtoexaminerelationshipsbetweenvariableswas
performedanddepictedasaclusterdendrogram.Adissimilarityindexof1.75waschosenfor
theclusteringcutoffinordertodescribehowlargergroupsofthevariableswererelated.Each
variablewascolor-codedbasedonwhichofthethreeclustersitwasinandthiscolor-coding
wasusedtoidentifyvariablesintherandomforestsplots.
OutcomesofinterestforthepredictivemodelsincludedLAZattwoyearsofage,thechange
inLAZfromenrollmenttotwoyears(ΔLAZ),andthefourcomponentsoftheBayley-III
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(cognitive,language,motor,andsocial-emotional).Aseparaterandomforestsanalysiswas
conductedforeachofouroutcomesofinteresttoselectandrankpredictivevariables.Condi-
tionalrandomforestsanalyseswereperformedtoaccountforthecorrelationsbetweenpredic-
torswithathresholdofPearson’scorrelationcoefficient(cid:21)0.2.Variableimportancevalues
(VIMP)werecalculatedforallpredictorsandthenscaledbasedonthepredictorwiththe
highestVIMPinthatanalysis(sVIMP).Inordertodeterminethedirectionoftheassociation
betweenvariablesandoutcomes,dependenceplotsbetweenpredictorsandoutcomesofinter-
estweregeneratedforthetop15predictors.
Asavalidation,penalizedlinearregressionanalyseswithSCADpenaltywereperformedon
thesamedatasets.ForSCADanalyses,dummyvariablesforcytokinemeasurementswerecre-
atedandifeitherthe50th–75thorthe>75thpercentilewasselected,theotherwasforcedinto
themodel.
Toassessthepredictabilityfromtherandomforestsanalyses,foreachoutcome,amean
squarederrorwascalculatedusingthepredictedvaluefromtherandomforestsmodelandthe
observedvalues,andthenpercentageofvariationexplainedbythepredictorswascalculated.
PercentageofvariationexplainedwasalsocalculatedfromtheSCADmodel.Allanalyseswere
doneusingRsoftware.Thestatisticalpackage‘party’version1.2–2fromFebruary27,2017
wasusedforconditionalrandomforests.Thestatisticalpackage‘grpreg’version3.0–2from
July11,2016wasusedforvariableselectionwithSCAD.
Ethicsstatement
ThePROVIDEstudywasapprovedbytheResearchReviewandEthicsReviewCommitteesat
TheInternationalCentreforDiarrhoealDiseaseResearch,BangladeshandbytheInstitutional
ReviewBoardsattheUniversityofVirginiaandtheUniversityofVermont.Informedconsent
wasobtainedfromparentsfortheirchild’sparticipationinthisstudy.Alldataanalyzedwere
anonymized.
Results
Completedatasetsofpredictorsincludedinthisstudywereavailablefor371subjectsfor
anthropometryand308subjectsforBayley-IIIneurodevelopmentalassessmentonceoutliers
wereremoved(Table1).661subjectshadcompleteenrollmentdatasets.Therewasnosignifi-
cantdifferenceinenrollmentcharacteristicsbetweeneithertheanthropometrydatasetorthe
neurodevelopmentaldatasetusedinthisanalysisandtheoriginalcohortexceptformaternal
education(Table2).TheaverageLAZattwoyearswas-1.7±1.6SD.TheaverageΔLAZfrom
enrollmenttotwoyearswas-0.9±1.6SD.33.3%ofchildrenhadanLAZ<-2SDbytwoyears
ofage(Fig1).TheaverageBayley-IIIscoreswere90.7±5.8,98.6±8.5,94.9±7.4,and91.2±5.8
forcognitive,language,motor,andsocial-emotional,respectively.
Hierarchicalclustering
Thehierarchicalclusteranalysisdemonstratedthreedistinctmajorclusters,similartoprevious
analysisofthisdata[6](S1Fig).Systemiccytokinescontinuedtoclustertightlyasintheprevi-
ousanalysis.However,enrollmentanthropometry,asopposedtoweek18anthropometry
usedpreviously,morecloselycorrelatedwithsanitation.Economicstatus(incomeandexpen-
diture)closelyclusteredwithbiomarkersofentericinflammation.CRPindexwasalsointhis
cluster.Overall,variablesfromeachclustertendedtorepresentthatclusteracrossourrandom
forestsanalyses.
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
Table1. VariablesmeasuredinthePROVIDEstudyutilizedinrandomforestsmodelstopredictlineargrowthandBayley-IIIneurodevelopmentalscoresattwo
yearsofage.
AtEnrollment Week6 Week12 Week18 Week24 Other
-Expenditure -Activin -Alpha-1 -Anti-LPSAb -Mannitol -CMVIgGpositivityatweek40
antitrypsin Recovery
-Gender -Anti-LPS -Calprotectin -DaysofDiarrhea -ElevatedCRPindex(measuredat6,18,
Ab 40,53weeks)
-Income -Ferritin -Mannitol -Daysofexclusivebreastfeeding -Rotarixvaccination(givenat10and17
Recovery through18weeks weeks)
-LAZ -RBP -Myeloperoxidase -Ferritin
-MaternalEducation -Reg1b -Neopterin -IL-10
-Mother’sHeightat -sCD14 -Reg1b -IL-1b
enrollment
-Mother’sWeightat -VitaminD -IL-4
enrollment
-Opendrainoutsidethe -Zinc -IL-5
home
-SepticTank/Toilet -IL-6
-SharedToilet -IL-7
-Watertreatment -MIP1b
-WAZ -RBP
-WHZ -sCD14
-TNFα
-VitaminD
-Zinc
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Table2. Enrollmentcharacteristicsofchildrenwhocompleted2yearanthropomorphicassessmentscomparedwiththosewhodidnot.
Variable ChildrenwithIncompleteDataforAnthropometryat2 ChildrenwithCompleteDataforAnthropometryat2 pvalue
years(n=290) years(n=371)
WAZatEnrollment -1.3±0.8 -1.3±0.8 0.31
LAZatEnrollment -0.9±0.9 -0.9±0.4 0.80
WHZatEnrollment -1.3±0.9 -1.3±0.9 0.14
AgeatEnrollment(days) 4.8±1.7 5.1±1.6 0.09
VaccinatedwithRotarix 131(45.2) 193(52.0) 0.08
AnyMaternalEducation 223(76.9) 347(66.6) 0.004
Expenditure(taka)(cid:3) 11,607±7833 11,529±6,742 0.63
Income(taka)(cid:3) 13,104±10,981 12,621±8,093 0.64
Mother’sWeightatEnrollment 49.4±9.7 49.2±9.2 0.91
(kg)
Mother’sHeightatEnrollment 150.3±5.7 150.4±5.4 0.61
(cm)
Male 164(56.6) 188(51.7) 0.13
TreatedWater 170(58.6) 233(62.8) 0.27
SepticTank/Toilet 147(50.7) 197(53.1) 0.54
NoSharedToilet 247(85.2) 317(85.4) 0.99
NoOpenDrainOutsideHome 118(40.7) 149(40.2) 0.89
Dataareexpressedinmean±SDforcontinuousmeasuresandcount(%)fordiscretemeasures.PvaluescalculatedbyMann-WhitneyUtestforcontinuousvariables
andχ2testfordiscretevariables.
(cid:3)1USD=approximately80.5Taka
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
Fig1.Anthropometryoverthefirst2yearsoflifeforthe371childrenwithcompleteanthropometric
measurements.Heightandweightweretakenat3-monthintervalsandtransformedtostandardizedZscores.TheX-
axisdepictsthechild’sagewhiletheY-axisdepictsthepercentageofchildreninthecohortwhohadaLAZ,WAZ,or
WHZ<-2SD.
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Predictorsidentifiedbyrandomforestsanalysis
sVIMPvaluesfromtheconditionalrandomforestsanalysesaredepictedforthetopranked
variablesinFig2anddependenceplotsforalloutcomesinS2–S7Figs.ForLAZattwoyearsas
astaticmeasure,maternalweight(indexsVIMP,1.0)andLAZatenrollment(sVIMP0.57)
weresubstantiallystrongerpredictorsthantheremainder.Therewasasubstantialdropin
sVIMPbetweenLAZatenrollmentandthenexthighestpredictor,whichwasmannitolrecov-
eryatweek12(sVIMP0.15).ForΔLAZfromenrollmenttotwoyears,LAZatenrollment
becamethestrongestpredictor(indexsVIMP,1.0),followedbymaternalweight(sVIMP
0.33).Overall,birthanthropometryandmaternalweightfarsurpassedallothervariablesin
termsoftheirabilitytopredictanthropometryattwoyearsandgrowth(Fig2A&2B).
InanalysisofBayley-IIIoutcomes,ingeneral,inflammationwasofgreaterimportance.For
cognitivescoreWAZatenrollmentwasthetoppredictor(indexsVIMP,1.0),followedby
income(sVIMP0.77),andLAZatenrollment(sVIMP0.71).Inflammatoryvariablessuchas
TNFαat18weeks(sVIMP0.41),sCD14atweek18(sVIMP0.33),andferritinatweek18
(sVIMP0.27),aswellastheeconomicvariableexpenditure(sVIMP0.36)wereweakerpredic-
tors(Fig2C).
Languagescoreswerepredictedbypresence/absenceoftherotavirusvaccine(index
sVIMP,1.0),IL5atweek18(sVIMP0.87),sCD14atweek18(sVIMP0.75),maternalweight
(sVIMP0.64),TNFαatweek18(sVIMP0.63),malegender(sVIMP0.60),andWHZatenroll-
ment(sVIMP0.56).Languagescoreswereinfluencedbyadiversecombinationoffactors
rangingacrossallthreegroupsofourclusteranalysis(Fig2D).
Formotorfunction,predictorsincludedcalprotectinat12weeks(indexsVIMP,1.0)fol-
lowedbyWAZatenrollment(sVIMP0.95),neopterinatweek12(sVIMP0.79),CRPindex
(sVIMP0.68),TNFαatweek18(sVIMP0.56),daysofdiarrheaatweek18(sVIMP0.51),IL5
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
Fig2.Randomforestsplotsofthetop15variablesselectedforlineargrowthandperformanceontheBayley-IIIscalesofinfantandToddler
Development.RandomforestsmodelswereconstructedforLAZattwoyears(A),thechangeinLAZfromenrollmenttotwoyears(B),andBayley-III
scoresattwoyearsofage.TheBayley-IIIiscomprisedof4components,namelycognitive(C),language(D),motor(E),andsocial-emotional(F).Color-
codingcorrelatestothethreeclustersidentifiedwhenallvariableswereanalyzedusingPearson’scorrelation(S1Fig).
https://doi.org/10.1371/journal.pntd.0006363.g002
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MaternalandinfantpredictorsofgrowthandneurodevelopmentinBangladesh
atweek18(sVIMP0.50),sCD14atweek18(sVIMP0.49),alpha-1antitrypsinatweek12
(sVIMP0.47),andmannitolrecoveryatweek12(sVIMP0.40).Motorscorewasstrongly
predictedbyvariablesthatgroupedtightlyinourhierarchicalclusteranalysisandincluded
biomarkersofentericinflammation.Biomarkersofsystemicinflammationandbirthanthro-
pometrywerealsostrongpredictors(Fig2E).
Thehighest-rankingpredictorofsocial-emotionalfunctionwassCD14(indexsVIMP,1.0)
followedbyincome(sVIMP0.95),WAZatenrollment(sVIMP0.77),LAZatenrollment
(sVIMP0.69),andTNFαatweek18(sVIMP0.47).Social-emotionalscoreappearedtobe
influencedbygutbarrierintegrity,economicmeans,systemicinflammation,andbirthanthro-
pometrics(Fig2F).
Theestimatesofthepercentageofvarianceexplainedinouroutcomesattwoyearsofage
fromtheconditionalrandomforestsanalyseswere35.4%and34.3%forLAZandΔLAZ
respectively;42.7%forcognitivescore,28.1%languagescore,40.8%formotorscore,and
37.9%forsocial-emotionalscore.
Predictorsidentifiedbyvariableselectionusingsmoothlyclippedabsolute
deviation(SCAD)
Inordertoidentifyriskfactorsthatindependentlypredictedoutcomes,variableselectionuti-
lizingSCADwasdone.Overall,SCADselected18of23(78%)ofpredictorsthatrandomfor-
estsassignedsVIMPvalues>0.50.Foranthropometryalone,SCADselected3of3(100%)of
predictorswithsVIMPvalues>0.50.ThisincludedLAZatenrollmentforbothLAZattwo
yearsandΔLAZfromenrollmenttotwoyears.ForLAZattwoyearsitalsoincludedmother’s
weight.
ForBayley-IIIoutcomesalone,SCADselected15of20(75%)ofvariableswithrandomfor-
estssVIMPvalues>0.50.ForthecognitivecomponentbothWAZatenrollmentandincome
wereselectedwhileLAZatenrollmentwasnot.Forlanguage,onlyWHZatenrollmentwas
notselected.SCADconfirmedtheimportanceofrotavirusvaccinestatus,IL5,sCD14,moth-
er’sweight,TNFα,andmalegenderinpredictinglanguagescores.SCADanalysisofBayley-III
motorscoresselectedcalprotectin,WAZatenrollment,neopterin,TNFα,andIL5,allof
whichrandomforestsselectedwithsVIMP>0.50.HoweverSCADfailedtoselectCRPindex
anddaysofdiarrheaatweek18.Forsocial-emotionalpredictors,SCADoverlappedwithran-
domforestson3of4variableswithsVIMP>0.50includingsCD14,income,andWAZat
enrollment.LAZatenrollmentwasnotselected(Table3).
LinearregressionmodelscreatedbySCADforeachoutcomeproducedestimatesofvari-
abilityforeachoutcomethatwere18.0%forLAZattwoyears,17.9%forΔLAZ,17.5%forcog-
nitivescore,12.9%forlanguagescore,13.6%formotorscore,and17.6%forsocial-emotional
score.
Discussion
Thekeydiscoveryofthisworkwasrankingtheimportanceofputativepredictorsofinfant
growthandneurodevelopmentanddemonstratingthattheyweredifferent.LAZattwoyears
ofagewaspredictedpredominantlybymaternalandbirthanthropometrics.Incontrast
developmentalscoresweremostprominentlypredictedbyinflammatorybiomarkers.These
datasuggestthatinterventionsaimedtoimprovegrowthandneurodevelopmentneedtobe
directedatbothimprovementsinmaternalandneonatalnutritionandreductionofgutand
systemicinflammation.
Thefindingthatperinatalchildandmaternalanthropometrypredictedlineargrowthreaf-
firmsseveralstudiesshowingbirthanthropometricsarestrongpredictorsofΔLAZ,suggesting
PLOSNeglectedTropicalDiseases|https://doi.org/10.1371/journal.pntd.0006363 May29,2018 10/20