The Effects of Iron Deficiency and Anemia on Mental and Motor Performance, Educational ...

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The Effects of Iron Deficiency
and Anemia on Mental and
Motor Performance, Educational
Achievement, and Behavior in Children:
An Annotated Bibliography
Catherine Nokes
Claire van den Bosch
Donald A.P. Bundy
ThepubhcatlonofthiSreportISmadepossiblebysupportfromOpportumtlesforMlCronutnent
InterventIOns(OMNI),aprojectoftheOfficeofHealthandNutntlon BureauforGlobalPro
grams FieldSupportandResearch,US AgencyforInternatIOnalDevelopment underContract
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..
butlOnofthePartnershipforChildDevelopmentwasmadepossiblebyagrantfromtheJamesS
...
,.. McDonnellFoundatIOn
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"' For additIOnal mformatlOn contact InternatIOnal NutntlOnal Anemia Consultative Group
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INACGpublicationsareavailablefreeofchargetodevelopmgcountnesandfor$350(US)to
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LrleSCiences ThiSreportISthesummaryofthepresentatlonsanddiSCUSSionsthattookplaceattheconsultatlve
INSTITUTE meetmgattheUmversltyofOxford,onSeptember16-17 1996 anddoesnotnecessarilyreflect
thesClentlficrecommendatIOns orViewsofINACG USAID, orthe InternatIOnalLifeSCiences
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fo Mcronutent
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CONTENTS
ALPHABETICALLISTOFINCLUDEDSTUDIES
INTRODUCTION 1
StudIesIncludedm theBIbhography 1
StructureoftheBIbhography 1
Age 1
ExpenmentalDesIgn 2
Date 3
OtherFeaturesoftheStudIesHIghhghtedm theBIbhography 3
LocatlOn ofStudy 3
IronStatusofChudren 3
LengthofTreatment 3
Developmental,CogmtlVe,orEducatlOnalOutcomeMeasuresUsed 4
HowtoUsetheBIbhographytoFmdSpecIficReferences theNumbenngSystem 4
GlossaryofTermsandKeytoAbbreviatlOns 5
SummaryofexpenmentaldeSIgnbystudIesexammmgtheeffectsofIrondefiCIency 6
INFANTSANDYOUNGCHILDREN(6-24MONTHS) 7
SummaryofFmdmgs 7
Short-termEffects ObservatlOnalStudIes 8
Short-termEffects InterventlOnTnals 10
Short-termEffects PreventatIveTnals 18
Long-termEffects ObservatIonalStudIes 19
Long termEffects Follow upofInterventlOnTnals 21
Long termEffects PreventatIveTnals 22
PRESCHOOLCHILDREN(2-5YEARS) 23
SummaryofFmdmgs 23
InterventlOnTnals 23
SCHOOL-AGECHILDRENANDADOLESCENTS(5-16YEARS) 27
Summaryoffindmgs 27
ObservatlOnal StudIes 27
InterventIOnTnals 28
SATELLITE ISSUES 33
AmmalStudIesandBlOlogICalMechamsms 33
AdultIronDefiCIency 33
OtherOutcomesofIronDefiCIency 34
PhYSICal FItness 34
InfectIOns 34
ConfoundmgandCovarymgFactors 34
References 35
READINGLIST OTHERREVIEWSANDRELATEDPAPERS 37
APPENDIXA TabulatedsummaryofstudIesmvestigatmgtheeffectsofIrondefiCIency(WIthandWithoutanemIa) onthe
developmentofmfantsandyoungchIldren, preschoolchIldren,andschool agechIldrenandadolescents 39
APPENDIXB LIStofStudIesUsed m the BIbhography,bycategory 59
APPENDIXC DescnptlOnofpsychometncanddevelopmenttestsusedm studIesmvestlgatmgtheeffectsofIDandIDA
on these functlOns 60
ALPHABETICAL LIST
OF INCLUDED STUDIES
AukettMA,ParksYA, ScottPH,WhartonSA(1986) IdJradlnata P, Pollitt E (1993) Reversal ofdevelop
Treatment with Iron Increases weight gain and mental delays In Iron-deficient anemic Infants
psychomotor development Arch DIS Child treated With Iron Lancet341 1-4 Reference 15
61 849-857 Reference 12 Johnson DL, McGowan RJ (1983) Anemia and
Bruner AB, Joffe A, Duggan AK, et al (1996) Infant behaVior Nutr Behav 1 185-192 Refer
Randomlsed study of cognitive effects of Iron ence 2
supplementation In non-anemic Iron-deficient KayshapP,GopaldasT(1987) Impactofhemanltlc
adolescentgirlsLancet348 992-996 Reference supplementation on cognitive function In un
42 derprIVIleged school girls (8-15 years of age)
Cantwell RJ (1974) Thelongterm neurological se Nutr Res 7 1117-1126 Reference 38
quelae ofanemiaIn Infancy PedlatrRes8 342 Lozoff B, Bnttenham GM, Vlten FE, Urrutia JJ
Reference 26 (1982a) BehaViouralabnormalitiesInInfantsWith
DelnardAS, GilbertA, DoddsM, Egeland B(1981) Iron defiCiency anemia In Pollitt EL (ed), Brain
IrondefiCiencyanemiaand behaViouraldefiCits biochemistryand behaViour Raven Press, New
Pedlatncs 68 828-833 Reference 1 York, pp 183-195 Reference 8
DelnardAS, ListA, Lindgren B, etal (1986) Cogni Lozoff B, Bnttenham GM, Vlten FE, et al (1982b)
tive defiCits In Iron defiCient and Iron defiCient Developmental defiCits In Iron defiCient Infants
anemic children J Pedlatr 108681-689 Refer effectsofageand seventyofIron lack J Pedlatr
ence 29 101 948-952 Reference 7
Gnndulls H, Scott PH, Belton NR, Wharton BA Lozoff B, Bnttenham GM, Vlten FE, et al (1982c)
(1986) Combined defiCiency of Iron and vita The effects of short-term oral Iron therapy on
min 0 In ASian toddlers Arch DIS Child 61 843 developmental defiCits In Iron-deficient anemic
848 Reference 3 Infants J Pedlatr 100351-357 Reference 6
Groner JA, Holtzman NA, Charney E, Mellltts E Lozoff B, WolfAW, UrrutiaJJ, Vlten FE (1985) Ab
(1986) Arandomized tnaloforal Ironontestsof normal behaVior and low developmental test
shortterm memoryandattentionspanInyoung scores In Iron-defiCient anemic Infants J Dev
pregnant women J Adolesc Health Care 7 44 Behav Pedlatr6 69-75 Reference 11
48 Reference 37 Lozoff B, Klein NK, Prabuckl KM (1986) Iron-defi
Heywood A, Oppenheimer S, Heywood P, Jolley cientanemicInfantsatplay JDevBehavPedlatr
o
(1989) BehaVioral effects of Iron supplemen 7 152-158 Reference 4
tation m mfants In Mandung, Papua New Lozoff B, Bnttenham GM, Wolf AW, et al (1987)
GUinea Am J Clln Nutr 50 630-640 Reference Iron defiCiency anemia and Iron therapy effects
17 on Infant developmental test performance Pe
Hurtado EK (1995) Cross linking a third data set diatriCS79 981-995 Reference 13
long term effects of Iron defiCiency dUring In Lozoff B, Jiminez E, Wolf AW (1991) Long-term
fancy and early childhood [abstract] Biennial developmental outcomeofInfantsWith Iron de
meeting of the Society for Research In Child fiCiency N Engl J Med 325 6876-6894 Refer
Development, Indianapolis, March-Apnl 1995, ence 25
217 Reference 22 Lozoff B, DeAndraca L, WalterT, Plno P (1996a)
n The Effects ofIron Defiexency on Chtld Development An Annotated Btblwgraphy
Does preventing Iron-deficiency anemia (IDA) Iron defiCiency and educational achievement
Improve developmental test scores? [personal In Thailand Am J Clln Nutr 50687-697 Refer
communication] Reference 19 ence 41
Lozoff B, Wolf AW, Jimenez E (1996b) Iron defi Seshadn S, H1rode K, Nalk P, Malhotra S (1982)
ciency anemia and Infant development effects BehaVioural responses ofyoung anemic Indian
ofextendedoralIrontherapy JPedlatr129382 childrentoIron-folicaCidsupplements BrJNutr
389 Reference 16 48233-240 Reference 34
Moffatt MEK, Longstaffe S, Besant J, Dureskl C Seshadri S, Gopaldas T (1989) Impact of Iron
(1994) Prevention of Iron defiCiency and psy supplementation on cognitive functions In pre
chomotor decline In high nsk Infants through school and school aged children the Indian
use of Iron-fortified Infant formula a random expenence Am J Clln Nutr 50675-686 Refer
Ized clinical tnal J Pedlatr 125527-534 Refer ence 39
ence 18 SoemantnAG, PollittE,Kim I(1985) IrondefiCiency
asklTE, HomgAS (1978)Theeffectsofshortterm anemiaandeducationalachievement AmJClln
therapy on the developmental scores of Iron Nutr42 1221-1228 Reference 36
defiCientInfants Pedlatncs92 21-25 Reference Soemantn AG (1989) Preliminaryfindings on Iron
5 supplementation and learning achievement of
askl FA, HonigAS, Helu B, Howanltz P(1983) Ef ruralIndonesianchildren AmJCllnNutr50698
fect of Iron therapy on behaViour performance 702 Reference 40
In non-anemic Iron defiCient Infants Pedlatncs Soewondo S, Husalnl MA, Pollitt E (1989) Effects
71 877-880 Reference 10 ofIrondefiCiencyon attention and learning pro
Paltl H, PevsnerB,Adler B (1983) Does anemiaIn cesses In pre-school children Bandung, Indo
Infancy affect achievement on developmental nesia Am JClln Nutr50667-674 Reference31
and Intelligence tests? Hum Bioi 55 189-194 WalterT, KovalskysJ,StekelA(1983) Effectofmild
Reference 23 Iron defiCiency on Infant mental development
Paltl H, MeijerA, Adler B (1985) Learning achieve scores Pedlatncs 102519-522 Reference 9
ment and behaVior at school of anemic and Walter T, De Andraca I, Chadud P, Perales CG
non-anemicInfants EarlyHumDev10217-233 (1989) Iron defiCiency anemia adverse effects
Reference 20 on Infant psychomotor development Pedlatncs
PollittE, Greenfield 0, Leibel R(1978) BehaVioural 84 7-17 Reference 14
effectsofIrondefiCiencyamongpre-schoolchil WalterT,deAndracaI,CastilloM,etal (1990) Cog
drenInCambndge, Mass FedProc37 487 Ref nitive effect at five years of age In Infants who
erence 27 wereanemicat12months alongitudinal study
Pollitt E, Leibel RL, Greenfield 0 (1983) Iron defi [abstract] PedlatrRes28295 Reference24
ciency and cognitive test performance In pre Wasserman G, GrazianoJH, Factor-Litvak P, etal
school children Nutr Behav 1 137-146 Refer (1992) Independenteffectsofleadexposureand
ence 28 Iron defiCiency anemia on developmental out
Pollitt E, YUniS F, Salem S, Scnmshaw NS (1985) come at age 2 years J Pedlatr 121 695-703
Reported In Pollitt E, Soemantn AG, Yunls F, Reference 21
Scnmshaw NS, Cognitive effects of Iron defi Webb TE, askl F (1973a) Iron defiCiency anemia
ciency anemia Lancet 19158 Reference 35 and scholastiC achievement In young adoles
Pollitt E, Saco-PollittC, Leibel RL, Vlten FE (1986) cents J Pedlatr 82 827-830 Reference 32
Iron defiCiency and behaVioral development In Webb TE, askl FA (1973b) The effect ofIron defi
Infants and pre-school children Am J Clln Nutr ciency anemia on scholastiC achievement
43 555-565 Reference 30 behaVioural stability and perceptual sensitivity
Pollitt E, HathlratP, Kotchabhakdl NJ, etal (1989) [abstract] PedlatrRes 28 294 Reference33
INTRODUCTION
I rondefioency(10)ISamajorpublIchealthproblem perswere selectedIftheywere conSIderedto have used
affectmgmorethan2000mIllionpersonsworldWide astrongexperImentaldeSIgn,wereagoodorrepresenta
IronISanessentialnutnentnotonlyforthenormal tIveexampleofthetypeofresearchmthearea,andgave
growth,health,andSUrvIValofchildren,butalsofortheIr a comprehensIve reVIewofthesubject
normalmentalandmotordevelopmentandcogmtIvefunc
tIonmg IrondefioenCYWIthanemIa(IDA) ISassocIated Structure of the IElUbliography
WithsIgnIficantlypoorerperformanceonpsychomotor
The bIblIographyconSIsts of5parts
andmentaldevelopmentscalesandbehaVIOralratmgsm
1 DetaileddescnptIonofeach expenmentalstudy
mfants,lowerscores on cognItive function tests m pre
schoolchIldren,andlowerscoresoncognItivefunctIon 2 Detailed tabulatIon/summary ofeach study
tests and educatIonal achIevement tests m school-age 3 BneftabulatedsummaryofstudIes
chIldren
4 AlIstofreVIewsgivenm thereadmglIst
Alarge number ofstudIes have been conducted to ex 5 Asummaryofstudies onrelated/satelliteIssues
amme the effects ofID and IDAon mental outcomes,
The followmg descnptIon ofthestructureofthebIblI
yetthe evrdenceIS notalwayscompletenorconclUSIve
ography refers only to those papers that have dIrectly
A need was Identified, therefore, to catalog each ofthe
exammed the relationshIp between Iron status m hu
studies so that they could be easily accessed and con
mansandItSeffectonmentalfunctIonanddevelopment
sulted,allOWingresearchersto reVIewtheavailabledata,
drawtheIrownconclUSIOnsfromtheavailableeVIdence, The bIblIography has been structured to focus on the
andverIfyanydatareVIewedorsummanzedelsewhere ageofsubjectsstudIed,theexperImentaldeSIgn,andthe
dateofpublIcation SpeCIficdetailsoneachofthesede
ThISbIblIographyISmtendedtobeusedm conjunction
scnptors are gIven below
WIth and as a supplement to the Oxford Bne! Chlld
Development and Iron Deficlency (by AlIzon Draper, Age The papers are descnbed and catalogued first ac
ILSI Press, May, 1997) cordingto the three mam age groups bemgstudIed A
diSCUSSIOnandovervIewoftheresultsforeachagegroup
Studies Included in the ISgIvenatthebegmmngofeachsectIOn Theagegroups
Bibliography are as follows
IncludedmthISbIblIographyarestudiesthathavelooked Infantsandyoungchildren SubJectsstudIedwere
directlyattherelatIonshIpbetweenIronstatusandsome childrenbetweenages6and24months,theout
mentalordevelopmentaloutcomem humans Because comemeasureswerementalandmotordevelop
thIS IS the mamfocus ofthebIblIography,asfar aspos mentandbehaVIor
SIble all ofthe papers publIshed m thIS area have been
Preschoolchildren Subjectsstudiedwerechildren
mcludedandmdlVlduallydescnbedandsummarIZed All
ages2to5years, theoutcomemeasurewascog
reVIews on thIS tOpIC are lIsted m the Readmg Listsec
mtIvefunctIon
tIon
School-age children and adolescents Subjects
Atthe endofthebIblIography,a descnptIOnofselected
studIed were children between ages 5 and 16
papersonrelatedtOpICS(SatelliteIssues)ISmcludedsuch
years,theoutcomemeasureswerecogmtIvefunc
asstudiesmvestIgatIngtherelatIOnshIpbetweenIronsta
tionandeducatIonaladllevement
tusandmentalandmotordevelopmentm anImals Pa-
2 The Effects ofIron Defictency on Chtld Development An Annotated BtbllOgraphy
Age IS emphasIzed because It seems to determme the education, and other nutrItIOnal defiCIts) could be re
observed level and type ofdevelopmental or cogmtlve sponsIble for the observeddevelopmentallevel ofchil
responsetoIrontreatment TheageofchIldrenwhomay dren
reqUITepreventaTIveorsupplementaryrrontreatmentalso
InmterventIOnstudies,thegroupsWithIDandIDAare
haslffipOrtantpubhchealthlffiphcaTIonsbecausechIldren
givenIronsupplementsafterthemitIalbasehnedevelop
m drlferent age groups are accessIble through different
mentalorpsychometncassessmentandthenthe devel
channels,thus,agealsodetermmesthemostappropnate
opmentalandpsychometncassessmentsarerepeatedto
dehvery system
determmethedegreeoflffiprovement InterventIOnstud
Expenmental Destgn Wlthm each age group, studIes Iesmaybedouble-bhnd,randomIZed,andtreatmentor
arefurtherclassIfiedundersubheadmgsaccordmgtoex placebo-controlled,butthosethatmcludeallofthesefea
perlffientaldeSIgn Because ofthe complexrange ofm tureswillhavethestrongestexpenmentaldeSIgnandthe
terventIOntrIalSthathavebeenundertaken(partICularly bestabilItyto mfercausalItybetweentheputatIvecause
m studies With mfants), studies have been groupedac (rronstatus)andtheoutcome(cogruTIonordevelopment)
cordingtothefollowmgsubcategones ThISISbecauseeachfeatureISdeSIgnedtoensureequal
Ityamongthegroupsmallrespects(forexample,mso
• ObservaTIonal
CioeconomICstatus(SES),maternaleducaTIon,andnutrI
.. IntervenTIon ThesearefurtherdlVldedmtostud tionalstatus)otherthanthetreatmenttheyweregivenso
Ies assessmg short-term or long-term effects that any confoundmg vanables are equally dIstnbuted
Short-termstudieslookedforanlffiprovementm betweenthe controland expenmentalgroups IfthIS IS
mentalormotoroutcomesfrom1weekto8months ensured, theexpenmentalgroups canbe drrectlycom
afterrronsupplementaTIon IronsupplementaTIon paredandtheumqueeffectoflfontreatmentonchIldren's
mtheseshort-termstudieswaseItherbneforex developmentdetermmed
tended (WithorWIthoutaplacebogroup) WIth
Inadouble-blmdtnal,boththesubjectsandtheperson
bnefsupplementaTIon,chIldrenweresupplemented
who assesses the response are unaware ofwhICh group
With Iron for 5 to 10 days only, With extended
the chlld has been aSSIgned to andwhat treatment has
supplementaTIon,chIldrenweresupplementedWith
been gIVen ThIS means that both groups will be dealt
rronformorethan2months Long-termstudIes
Withbytheexperlffientersmthesamewayandalsothat
looked at the effects ofID and IDAor the ben
onegroupofchildrenwillnotfeelmoreorlesspnvileged
efits ofIron supplementatIOnmorethan 2years
thananother
later ThesestudiesalsomcludeprospecTIvestud
Ies(notreatmentgIven) InarandomIzedtnal,childrenareaSSIgnedrandomlyto
thetreatmentgroups(treatmentandnotreatmentortreat
• PreventaTIve
mentandplacebo) RandomaSSIgnmentshouldensure
AnunderstandmgoftheexpenmentaldeSIgnISlffiportant thatall thecharactenstICsofthe two groupsareSImIlar
formterpretlngtheresultsfromeachstudyandfordraw sothatanydIfferencesamongmdlVlduals, for example,
mgvalIdconclUSIOns Thus,abnefdescnptlonofthead differences m SES, are equally dlstnbuted between the
vantagesanddIsadvantagesofeachexperlffientaldeSIgn two groups
ISgIvenbelow
Inaplacebo-controlledtrIal,aneffectivecontrolISpro
InobservatIOnal,cross-sectIOnal,orcase-controlstudIes, Videdbytheplacebo,anmertpreparationformulatedto
rronandpsychometrICordevelopmentalmeasurements appearmdIstmgmshablefromtheIronsupplement ItIS
are taken from experlffiental groups at one TIme pomt ImportanttogIveaplacebotothecontrolgroupbecause
only ThesetypesofstudiescanshowthatonecondItion It accounts for unspeCific dIfferences m developmental
(developmentalstatus) IS associatedWithanother (Iron orcogmtIveresponsesthatanseslffiplyfromthechildren
status) but they cannot determme the causahty ofthe bemggivensomethmgratherthannothmg Withoutapla
relatIOnshIp Forexample, otherfactors assOCIatedWith cebo group It18 notpOSSIbleto determmewhetherIm
Ironstatus(suchasSOCIOeconomICconditIOns,maternal provementm developmentor cognItIOn observedafter
Introductxon 3
IronsupplementatIOnISduetoImprovementmIronsta (Appendix A) because they are conSIdered Important
tus or to somethmg related to Iron but not Iron Itself, formterpretmgresultsandforcomparmgresultsacross
suchaslowbIrthweIght,lackofbreast-feedmg,orenVi studIes ThesecharactenstIcsmcludethelocationofthe
ronmental dIsadvantage study,the Iron status ofchIldren at baselme,the length
oftreatment,andthedevelopmental,cogmtIve,oredu
The mclusIOn ofa nonanemIc, Iron-sufficIent control
cational outcome measures used
group (whICh mayormaynotbematchedWiththe ID
or IDA group), although not essential to a treatment Locatton ofStudy It IS conceIvable that baselme dIffer
or placebo-controlled tnal, IS Important for two rea encesandresponsesto Irontherapycouldvaryaccord
sons FIrst,themclusIOnofanIron-suffiCientgroupcan mgtotheenVIronmentmwhIChthechIldhasgrownup
helpdetermmewhetherthereISanymitIaldefiCItmde Forexample,someenVIronmentsmayputchIldrenatm
velopmentalorcogmtIveoutcomebetweenthechIldren creased nsk ofanerrua or ID whereas others maypro
With ID or IDA and the Iron-suffiCIent chIldren Ifno VidechIldrenWithpsycholOgicalbuffersthatpreventsuch
defiCIteXistsatbaselme,anImprovementfollowmgtreat hematolOgiCImparrmentImpedmgdevelopment
mentwouldnotbeexpected Second,anIron-suffiCient
Iron Status ofChtldren Whether chIldren recrUIted to
groupcanhelpdetermmewhethertheadverseeffectsof
the study have ID or IDA IS clearly speCified because
ID or IDA on performance are fully or only partially
eVidencesuggeststhattheeffectsofthesecondItIOnson
reverSIble followmgtreatment, that IS, whether the Im
developmentorpsychometrICfunctionmaydIffer Usu
provement m performanceofchIldrenWith ID or IDA
ally,onlyIDAISassOCIatedWithlowerdevelopmentalor
whoreceIvedIrontreatmentISlargeenoughforthemto
cognItivescores,butthISISnotexclUSIvelysoandItISnot
catchuptotheIron-suffiCientcontrolgroupbytheend
easyto dIfferenTIatewhethertheeffectondevelopment
ofthestudy
orcogmtIonISduetotheseventyofthedefiCiencymIron,
IncondItIOnsmWhIChbenefitsfromtreatmenthavenot theageofonsetofdefiCIency,ortheduratIOnofthedefi
been commonly observed, It IS chffi.cult to determme Ciency
whether thIS IS because there are no dIrect effects of
AdIstmctIonhasalsobeenmadebetweensevere,mod
IDA on performance or whether there are effects of
erate,andmIldIDA WherepOSSIble,theauthors'defim
IDAthatarenotcorrectableWithtreatment Ifthelatter
tIons havebeenused, otherWIse, themeanhematolOgiC
ISconSIderedthecase,thIScouldbestudIedmapreven
values WIthm each group as speCIfied m the paper are
tatIvetnalm whIChchIldrenwhoaresupplemented(by
used ThISISbecause,whIletherearemternatIOnalcnte
recelVlngIron-fortlfiedmIlkformula, for example) and
nafordefinmgIDA,(Bb 110glLforchIldrenbetween6
protectedfrombecommgIrondefiCIentWithanemIaare
months and 6 years ofage (WHO, 1972), the studIes
comparedWithchIldrenwhoarenotsupplemented Al
havenotapphedthesecrltenaconSIstently Forexample,
thoughpreventativetnalshavenotbeencommonlyun
accordmgtoLozoffetal (1987),ahemoglobmconcen
dertaken m thIS areaofresearch, theyare wnslderedto
trationless than 100gldL (or 100giL, to convertcon
haveastrongexperImentaldesIgn
venTIonalvalues m gldLto SIvalues mgiL, mulTIplyby
Date Studies are presentedWIthm each ofthe subsec 10)sIgmfiesmoderateanemIaandgreaterthanorequal
TIons(eg,underobservaTIonalstudies,mtervenTIontnals, to 100 g/dL andless than 11 0 g/dL slgmfies mudane
orpreventatIvetrIalS)accordmgtotheyearmwhIChthey mia Ontheotherhand,accordmgtoDemardetal (1981),
were publIshed The date ofpublIcaTIon IS conSIdered valuesofhemoglobmgreaterthan11 0gIdLandaserum
ImportantforputtmgthestudIesmtoahIstoncalperspec ferntlnlessthanorequalto9nglmL(or9 giL,toconvert
tIve and for observmg how the research methods and conventionalvaluesmnglmLtoSIvaluesm giL,multiply
questionsprogressedovertIme by1)SIgnllysevereID,andvaluesforhemoglobmgreater
than11 0gIdLandserumferntmbetween10and19ngl
Other Features of the Studies mLsIgmfymIldID WhenastudymcludessubJectsfrom
Highlighted iII'lI the Bibliography more than one category ofseventy, It IS claSSIfied ac
cordmgto the most severelyIron-defiCIentgroup
Certamkeyfeatures ofeach paperpresentedhavebeen
emphaSIZed m the text and m the tabulated summary
4 TheEffectsofIronDefiCIencyon ChIldDevelopment AnAnnotatedBIblIOgraphy
LengthofTreatment Thelengthoftreatmenthasbeen catIOnalachIevementISan lffiportantoutcomebecause
specIfiedbecauseItISlffiportantfordetermmmgthede effects on school performance have potenoal to mflu
gree oflffiprovement m Iron status and the replemsh encepohey,ItISaglobalmeasureandchildren'sperfor
mentofIronstores ItISsupposedthatvery-short-term mancewillbeheavilymfluencedbyenVIronmentaland
therapyofless than or equalto 10 days (termed "bnef socIO-emooonalcondItIOnsathomeandatschool For
supplementatIOn") willnotresultmanysIgmficantnse example,ImprovementsmeducatIOnalachIevementfol
m hemoglobm levels but will reduce the level ofID lOWingIrontreatmentmaybedIfficulttomeasureIfchil
Longer-term Iron supplementatIOn of2 to 8 months dren are not attending school regularly or Ifthe class
(termed"extendedsupplementatIOn")willresultmanse room IS not conduslveto learnmg
m hemoglobm and should therefore correct anemia If
present Howto Use the Bibliography to
Find Specific References: The
Developmental,CogmtJ.ve,orEducatJ.onalOutcomeMea
Numbering System
suresUsed ThetestsusedneedtobesenSIovetochanges
m Iron status, culturally acceptable, rehable, and valId A numbenng system has been used so that the papers
for thestudypopulatIOn MeeTIngallthesecntenamay descnbed m detail m the mam bodyofthe text can be
beextremelychfficult,whIChmayaccountforthefailure easilylocated EachreferencehasbeenassIgnedanum
ofsomestudiestoshowlffiprovementm the outcomes ber,whIChISgIveneachomethe reference IShsted Ex
measured after Iron supplementaoon amples ofhow to use the numbenng system to find a
referenceareasfollows IfthenameofthefirstauthorIS
TheoutcomesusedtomeasuretheeffectsoflDandIDA
known,lookmthesecoonAlphabeticalListofIncluded
must vary accordmg to the age ofthe children bemg
Studies(onpages1and11)andfindthereferencenumber
studIed MoststudiesWith mfantslookedatdifferences
ofthepaper (gIvenattheendoftheCItatIOn) AwrItten
ontheBayleyScaleofInfantDevelopment(BSID),whICh
summaryofthe papercan be found WIthmthe text, m
prOVIdesmdIcatorsofmentaldevelopment,motordevel
wmchpapersarediscussedm numencalorder
opment,and,mdrrectly,behaVIor Bybemgaglobalmea
sure ofdevelopment, BSID IS often cnocized as bemg Alternaovely,to find, for example,allthe observaoonal
msenSIuvemthecontextofIDbecauseofItsmabihtyto studIesconductedWithmfantsseveraloptIOnsareavaIl
IsolateeffectsonspecIficfunctIOnsandItSlowtest-retest able
rehabilitymchIldrenyoungerthanage18months How
(a) foradetaIleddescnptIOn,lookmtheInfantsand
ever,mtheabsenceofgoodalternaovetestsofdevelop
YoungChildren(6-24months)secoonofthetext
ment, BSIDISthemostcommonlyusedoutcomemea
under the subheadmgs Short-term Effects Ob
surem mfants Thus,ItSWideusagefacilitatescompan
servatIOnal Studies (page 8), and Long-term Ef
sonofresultsacrossstudies Indeed,whendrawmgcom
fects ObservatIOnal Studies (page 19),
pansonsacrossstudies,the term"patternmg" hasbeen
usedtodescnbeSItuatIOnsmwhIChagroupconSIstently (b) for a hst, Table 1m the Infants column and the
faIls certam Items or subtasksofa developmentalmea ObservatIOnal studIes row (page 6), or m Ap
sure StudIesWithpreschoolchildrenhavetendedtofo pendlXAm boththeAgeand StudydeSIgn col
cus on trymg to Isolate the specIfic cogmove functIOns umns (page 39)
whIchareaffectedbyIDandIDA Inpractlce,however,
(c) foradetailedtabulaoon,studIesarehstedmAp
therangeoffunctIOnswhIchcanbemeasuredmanyone
pendIXBaccordmgtotheageofthesubJectsand,
studyISlImItedandtheculturalVahdltyoftheteststhem
for mfants and young chIldren, accordmg to
selves maybequesoonable
whetherthestudIeslookedatshort-termorlong
Studies With school-age children have tended to mea termeffects (page59)
sureeducaoonaland/orcogmovefuncoon Whileedu-
IntroductIOn 5
Glossary of Terms and Key to AcomplementarykeywordsectlonISmcludedWith
Abbreviations each annotatlon Studtes repomng abaselmepOSI
tlve aSSOCIatIOn between hematologIC lillpatrment
Each CItatlon m the text IS annotated at the begmnmg
andlowdevelopmentaltestscores are mdicatedby
accordmg to Its Importance, expenmental deSIgn,
anastensk(*) Studiesrepomnganassociatlonbe
baselmeresults,post-mterventlonandfollow-upresults,
tween trontreatmentanddevelopmentalImprove
and conclusIOns The other subsectlon mcludes detatls
ment are mdtcatedbya dagger (t) Avalue ofp<
ofanynoteworthyfeatures ofthe paper (eg,Ifthe pa o
05 IS consIdered a statisticallysIgmficant result
perusefullydtscussesbiOlOgicalmechanIsmsortherole
ofpotentIally confoundmg vanables) Severalterms and abbreVlatlons are used through
out Thesearedefinedasfollows
Hematology DevelopmentalMeasures Studydeslgn
Hb=hemoglobm BSID =Bayley Scale ofInfant DIfference-usedwhenrepomngresults,referstoa
Development statlstICallySIgmficantdifference (atleastp <005)
ID =Iron defiCiency IBR =Infant BehaVIOr Record Interventlon-theIDAandIDgroupsaregivenIron
Withoutaneillla (subscale ofBSID) supplementatiOn,usuallyafterbaselmeassessment
IDA = Iron defiCiency MDI=MentalDevelopmentIn NonaneilllCcontrol-anonaneilllCgroupISmcluded,
Withaneillla dex (subscale ofBSID) usuallymatchedtotheIDAorIDgroupbyageasa
mmlillUill,andgiventhesamedevelopmentalassess
PDI=PsychomotorDevelopment
ments,mthesestudiesthenonanemlCgroupISoften
Index (subscale ofBSID)
= giventhesameIronorplacebomterventlonsasthe
WISC Wechsler IntellIgence
IDAandIDchildren
ScaleforChildren
ObservatiOnal-onlybaselmehematologICand de
velopmental measurements are taken from groups
tobecompared
Placebo control-a subgroup ofthe IDA and ID
childrenaregiven aplacebo accordmg to thesame
procedureastheadmmistratIonoftheIronsupple
ment
Preventative-anemIa m subjects from an at-nsk
populatIOn IS prevented early m hfe With prophy
lactIC supplementatIOn, and development ofthIS
groupIScomparedWiththedevelopmentofsubjects
fromthesamegroupnotgivensupplements
RandomIzed-subJects are randomly assIgned to
treatmentandplacebogroups
*StudIesthat report abaselmeposItIve assOCiation
betweenhematolOgiClillpatrmentandlowdevelop
mentaltestscores
t StudIesthatreportanassociatlonbetweenIrontreat
mentanddevelopmentallillprovement
Appen<bxC gIvesa summaryofthe allthepsychometnc, developmentandeducatIOnaltestswhIchhavebeen
usedillstudIesofIDandIDA