The"HealthyImmigrantParadox"inPerinatalHealth:Evidence
fromDifferencesbetweenNativesandMigrantsinBirthWeightin
SpainandEcuador
HéctorCebolla‐Boado
AssociateProfessor,DepartmentofSocialStructure,UNED,Spain
[email protected]
LeireSalazar
AssociateProfessor,DepartmentofSocialStructure,UNED,Spain
[email protected]
Abstract:
Thispaperexploresdifferencesinperinatalinequalitybetweenmigrant‐and
native‐originnewbornsinSpainand,morespecifically,differencesintheweightat
birth,anoutcomethatishighlycorrelatedwithhealthandeducationinchildhood
andadulthood.Previousliteraturehasshownthat,inlinewiththe"healthy
immigrantparadox",thechildrenofimmigrantmotherstendtohavealowerrisk
oflowbirthweight.
Forouranalysiswebuiltadatasetcombiningtwosourcesofadministrativedata,
oneforSpain,thereceivingcountry,andoneforEcuador,thesendingcountry.On
theonehand,theEcuadorianRegisterofBirthsmadeavailablebytheNational
InstituteofEcuadorianStatistics(InstitutoNacionaldeEstadística),whichresults
fromthesystematizationofbasicinformationofeverybirththattookplaceinthe
country.Ontheotherhand,theSpanishbirthscamefromthePopulation
MovementStatistics(EstadísticadelMovimientoNaturaldelaPoblación,EMNP)in
theChildbirthStatisticsBulletin(BoletínEstadísticodelParto)providedbythe
NationalStatisticsInstitute(InstitutoNacionaldeEstadística).TheSpanishdata
alsohaveanadministrativenature(registers)andcovertheentirepopulationof
newlyborninSpaininacompletenaturalyear.Inbothcasesweanalyzedatafrom
2013,whichisthemostrecentyearavailablesimultaneouslyinbothcountries.We
comparethreerelevantgroupsofnewborns:thosefromSpanish‐bornmothers
(N=265,968),fromEcuadorian‐bornmotherssettledinSpain(N=166,079),and
fromEcuadorianmotherslivinginEcuador(N=4,612).Thecomparisonof
migrantstoSpainwithnon‐migrantsinthecountryoforiginprovidesan
interestingscenariototestthevalidityofthepotentialexistenceofpositive
selectioninthemigrantpopulation.
Figure1.Estimatedaveragebirthweightforthethreegroups
Ourpaperdoesnotonlyconfirmthatthewell‐knownepidemiologicalregularityof
healthierbabiesamongmigrantsinadvancedeconomies,namelyanadvantageof
immigrant‐originbabiesintermsofavoidinglowbirthweight,alsoappliesto
Spain(seetheFigureabove).Byusingquintileregression,itconfirmstheweight
advantagethroughoutthewholedistributionofweight.Intheotherextreme,when
thebaby’sweightisabove4,000grams,athresholdthatisassociatedwith
increasedhealthrisksforthenewborn,migrant‐originbabiesweighabout80
gramsmorethannative‐originonesandover250gramsmorethannewbornsin
Ecuador.Ouranalysisincludesseveralrelevantcontrolsincludingindirect
measuresofdifferences,attheprovincelevel,inthecoverageandqualityofhealth
care.
Wethereforecontributetotheliteraturebyconfirmingtheconsistentlyhigher
birthweightenjoyedbythechildrenofmigrantmothersinacountrysuchas
Spain,whereimmigrationisarecentphenomenonandwhereaccesstoquality
healthcareisuniversalandfreeofcharge.Inaddition,thecomparisonbetween
babiesfromEcuadorianmothersborninSpainandEcuador,respectively,provides
evidenceconsistentwiththeexistenceofpositiveselectionamongmigrants.Last,
theuseofquantileregressionmodelshasallowedtofindoutthatthehigher
averageweightofnewlybornbabiesfromimmigrantmothersbecomesa
disadvantageatthehighestendofthedistributionofweight.