Somatic growth from birth to 6 months in low birth weight, in Bukavu, South Kivu, Democratic Republic of the Congo

Original

article

Somatic

growth

from

birth

to

6

months

in

low

birth

weight,

in

Bukavu,

South

Kivu,

Democratic

Republic

of

the

Congo

Croissance

somatique

de

la

naissance

a` 6

mois

des

nouveau-ne´s

de

faible

poids

de

naissance

a`

Bukavu,

Sud-Kivu,

Re´publique

De´mocratique

du

Congo

R.

Mbusa-Kambale

*

,

M.

Mihigo-Akonkwa

,

N.

Francisca-Isia

,

S.

Zigabe-Mushamuka

,

J.

Bwija-Kasengi

,

A.

Nyakasane-Muhimuzi

,

O.

Battisti

,

B.

Mungo-Masumbuko

a_{FacultyofMedicine,CatholicUniversityofBukavu,Bukavu,South-KivuProvince,DemocraticRepublicofCongo}

b_{DepartmentofPediatrics,ReferenceProvincialGeneralHospitalofBukavu,Bukavu,South-KivuProvince,DemocraticRepublicofCongo} c

DepartmentofPediatrics,UniversityofLiege,Belgium Received29June2017;accepted30November2017

Availableonline30May2018

Abstract

Background.– Lowbirthweight(LBW)isoneoftheleadingcausesofperinatalandinfantmorbidityandmortality,aswellasofimpaired growthandneurocognitivedevelopment.Thisstudyaimedtoevaluatetheevolutionofanthropometricparametersandthenutritionalstatusof LBWinfantsandtoanalyzefactorsinfluencingthegrowthfailureduringtheirfirst6monthsoflife(oradjustedage).

Methods.– Thiswasaprospectivecohortstudyfor6months,including100infantsbornwithLBWand100infantsbornatfull-termandwith normalweight.Thez-scoresweightforage,heightforage,headcircumferenceforageandweightforheightwerecomputedwiththesoftware EpinutandWHOAnthro2005.Descriptivestatistics,bivariateanalysisandmultivariablelogisticregressionanalyseswereemployedtoidentify factorsassociatedwithgrowthfailure.Growthfailurewasdefinedasadecreaseinweightz-score(standarddeviationscore)ofover0.67duringone ofthestudy’speriods.Thestatisticalsignificancethresholdwasfixedat0.05.

Findings.– At6monthsoflife(oradjustedage),15.3%ofLBWwereunderweight,51.4%werestunted,4.2%hadanemaciationand25%had aheadcircumferenceforage<2z-scores.Riskfactorforgrowthfailurewasmalesex(OR=1.56[95%CI:1.03–2.23]).Thesymmetrical intra-uterinegrowthretardationwasaprotectorfactorforgrowthfailure(OR=0.49[95%CI:0.25–0.98]).

Conclusion.– Intheshortterm,LBWinfantsmayhavegrowthdisorders.Itisnecessarytoemphasizetheimportanceofgrowthassessmentof LBWchildrenandpropereducationoftheirmothersaboutnutritionoftheirchildrenforearlyandtimelydiagnosisandmanagementofgrowth retardationandpreventionofsubsequentproblems.

# _{2018ElsevierMassonSAS.Allrightsreserved.}

Keywords:Lowbirthweight;Nutritionalstatus;Somaticcatch-up;Infant

Re´sume´

Introduction.– Lefaiblepoidsdenaissance(FPN)constituel’unedeprincipalescausesdelamorbidite´ etdelamortalite´ pe´rinatales,des troublesdecroissancesomatiqueetdude´veloppementneurocognitifdel’enfant.Cettee´tudevisea` e´valuerlestatutnutritionneldesnourrissonsne´s avecunFPNetlesfacteursinfluenc¸antleure´checdecroissancedurantles6premiersmoisdevie.

Me´thodologie.– E´ tudedecohorte prospectivedynamiqueincluant100 nourrissonsne´savecun FPNet100 nourrissonsne´sa` terme et eutrophiques.Lesindicespoidspouraˆge,taillepouraˆge,pe´rime`trecraˆnienpouraˆgeetpoidspourtailleonte´te´ analyse´savecEpinutetWHO

ScienceDirect

www.sciencedirect.com

Revued’E´ pide´miologieetdeSante´ Publique66(2018)245–253

*Correspondingauthorat:DepartmentofPediatrics,ReferenceProvincialGeneralHospitalofBukavu,Bukavu,South-KivuProvince,DemocraticRepublicof Congo.

E-mailaddress:richkambale7@gmail.com(R.Mbusa-Kambale).

https://doi.org/10.1016/j.respe.2017.11.011

Anthro2005.Desstatistiquesdescriptivesetdesanalysesbivarie´esetmultivarie´esparre´gressionlogistiqueonte´te´ utilise´espourde´terminerles facteursassocie´sauxtroublesdecroissance.L’e´checdecroissanceae´te´ de´finiparunediminutiondel’e´cartre´duitdupoidsdeplusde0,67pendant l’unedespe´riodesd’e´tude.Lavaleurdep<0,05ae´te´ conside´re´ecommesignificative.

Re´sultat.– A` sixmoisdevie,15,3%desFPNavaientunde´ficitponde´ral,51,4%avaientunretarddecroissance,4,2%avaientunee´maciation et25%avaientlepe´rime`trecraˆnienpouraˆge<2z-scores.Eˆ tredesexemasculine´taitunfacteurderisqued’e´checdecroissance(OR=1,56[IC 95%:1,03–2,23]).Leretarddecroissanceintra-ute´rinesyme´triquerepre´sentaitunfacteurprotecteurcontrel’e´checdecroissance(OR=0,49[IC 95%:0,25–0,98]).

Conclusion.– A` courtterme,lesnourrissonsne´savecunFPNpeuventpre´senterdestroublesdecroissance.Lesme`resdesnourrissonsne´savec unFPNdevraienteˆtresensibilise´essurl’importancedusuivire´gulierenvued’unde´pistagepre´cocedecestroublesdecroissance.

# _{2018ElsevierMassonSAS.Tousdroitsre´serve´s.}

Motscle´s: Faiblepoidsdenaissance;Statutnutritionnel;Rattrapagesomatique;Nourrisson

1. Introduction

Lowbirthweight(LBW),definedasbirthweightlessthan 2500g [1], is a real public health issue. It is the result of prematurityorintra-uterinegrowthretardation(IUGR)orbeing smallforgestationalage(SGA)[2].Thecausesofprematurity andthoseofIUGRarewellknown[3–5].LBWisaconcernof bothparentsandhealthprofessionals.It isoneof theleading causesof perinatal andinfant morbidity andmortality, long-termmetabolic disorders, andimpaired growth and neuroco-gnitivedevelopment [5–7].Worldwide,morethan20 million infants are born with LBWeach year, representing a global prevalenceof15.5%.Approximately95%oftheseLBWoccur in low- and middle-income countries (LMICs) [8]. In the DemocraticRepublicofCongo(DRC),theprevalenceofLBW hasvariedovertheyears,rangingfrom11%in2001[9]to7.1% in2014[10].Growthmonitoringisofparticularimportanceina developingcountrysuchasDRCwheretherearehighratesof malnutritionandinfectiousdiseases[11],acrudemortalityrate above the average for sub-Saharan countries [12] and the highest under-5 mortality rate in Africa [13,14]. Growth monitoringinLBWinfantsis,however,complicatedbyseveral factors.Foremostly,thegrowthofLBWinfantsischaracterized byearlysuboptimalgrowth followedbyaperiod ofcatch-up growth [15,16]. Secondly, LBW infants are aheterogeneous groupofvariablebirthweight,sex,gestationalages,associated morbidities and appropriateness for gestational age, all factors which affect growth [15–18]. Thirdly, controversy surrounds the ideal growth of LBW infants: rapid catch-up growthisadvantageous withrespecttoimproved neurodeve-lopmental outcomes, fewer psychosocial problems in later childhoodandlowerriskofpersistentshortstaturebutmaybe associatedwithanincreasedriskofchildhoodobesityandother metabolic complications [15,19]. Almost nothing is known aboutthegrowthofLBWinfantsintheDRC.Theaimofthis studywastoevaluatethegrowthparameters(weight,lengthand headcircumference)frombirthto6monthsofage(or gestation-adjustedage)ofLBWinfantsadmittedtotheneonatologyunit andlaterfollowedinthematernalandchildhealthunit(MCHU) ofReferenceProvincialGeneralHospitalofBukavu(RPGHB). Secondly,thisstudyaimedtoanalyzefactorsinfluencinggrowth failureduringthefirst6monthsoflife.

2. Populationandmethods 2.1. Studyarea

Thisdynamic prospectivecohort study was carriedout in outpatientinfantsintheMCHUofRPGHB.Thishospitalhas 385 beds, handles6400admissionsand 4900outpatientsper year.ItisoneofthemainhealthcarefacilitiesinBukavu,acity of more than 700,000inhabitants in South-KivuProvince in eastern DRC. It organizes tertiary care services. Within the RPGHB,MCHUactivitiesarecarriedoutbythepediatricsand obstetrics departments. This study was carried out in the MCHUofthepediatricsdepartment,whichprovidespre-school counselling andvaccination of children and maternal health education.

2.2. Samplesize

Anexternalfollow-upprogramintheMCHUforallinfants born in RPGHB has been established by the pediatrics department since January 2016 in order to ensure early screening of impaired growth in children. Follow-up is organizedafterinformedconsentfromthemother.Thus,from JanuarytoDecember2016,183LBWinfantsand413infants born at full-term and with normal weight (FTNW) were followed in the MCHU of RPGHB. These newborns were selectedastheyarrivedinRPGHBandeachwasfollowedfor 6monthsintheMCHU.Thesizeofoursamplewascalculated bytheLorentzformula:

n¼t

2_pð1-pÞ

m2 ¼

ð1:96Þ20:070:93 ð0:05Þ2

100 individuals (n: sample size; t: 95% confidence level [typical value 1.96]; P: probability of LBW [7% according toDemographicandHealthSurveysDRC2014];m:marginof error[5%]).

These 100 individuals were randomly selected from this population of 183 LBW infants, based on a simple random sampling.Wealso randomlyselected, fromasimple random sampling, 100 control individuals from this population of 413FTNWinfants(Fig.1).

R.Mbusa-Kambaleetal./Revued’E´ pide´miologieetdeSante´ Publique66(2018)245–253 246

2.3. Inclusionandexclusioncriteria

The study included infants with the following characte-ristics:

birthweightless than2500g and;

informedconsentofthemotherobtained. Infantsfromtwin pregnancies and those whose mothers refused an external follow-uptothe RPGHBwereexcluded.

2.4. Datacollection

2.4.1. Descriptionofpopulation

Intheneonatologyunit,aquestionnairewasadministeredto collectthefollowinginformationonmothers:

maternalage(inyears); parity(primipara/multipara);

education status (unschooled/primary school/secondary school/university);

maritalstatus(married/unmarried); socioeconomicstatus(low/medium/good); siblingsize(5/>5);

interpregnancyinterval(<24months/24months)and; parentoccupation.

Informationonnewbornswerecollectedfrommothersand in medical records of the neonatology unit. Data collected were:

gender(male/female);

gestationalage(preterminfant/full-terminfant); trophicity (SGA/IUGR/AGA);

anthropometric birth parameters: weight (in gram), length (incm) andheadcircumference(cm).

Themother’sschoollevelwassubdividedintotwoclasses: low (for mothers unschooled or primary school), good (for those havingsecondary school or university). The socioeco-nomicstatuswasdeterminedonthebasisofahouseholdwealth scoreasproposedbyBangiranaetal.[20]andFilmeretal.[21]

onthebasisofthehousehold’smaterialassetsandonthebasis

ofseveralcharacteristicsofthehousesuchasmaterialsusedfor walls and for the roof. The household wealth score was obtainedbyaddingupthepointsassignedtotheaboveitems. Preterminfantwasdefinedasaninfantbornbefore37weeksof gestationalageandafull-terminfantasaninfantbornbetween 37 and 42 weeks of gestational age [22]. SGAwas defined, firstly, as a birth weight below the 3rd percentile of the AUDIPOG’sreferenceofbirthweight-for-gestational-age[23], which is gender specific as recommended by the WHO; secondly, SGA was defined by harmonious anthropometry; IUGRwasdefinedasabirthweightbelowthe3rdpercentileof the AUDIPOG’sreferenceof birth weight-for-gestational-age and with non-harmonious anthropometry; AGAwas defined as aninfantwhosebirthweightisbetweenthe3rdpercentile and the 97th percentile of the AUDIPOG’s reference of birth weight-for-gestational-age. Rohrer’s ponderal index in newborns PI¼ Weight ðingÞ

height ðincmÞ3

ð Þ100

 

hasbeenusedtoassess symmetrical orasymmetricalIUGR.

2.4.2. Anthropometricmeasurementsandfeedingpractices After hospital discharge, the newborns were reviewed in consultationtwoweekslaterandthenonceamonthforupto 6 months in the MCHU. Weight was measured using an electronic baby scale(SECA1type 435)withaprecisionof 10g. Lengthwasmeasuredtothe nearestmillimeterusing a gauge(ADE-MechanicalBabyLengthMeasuringgauge).The head circumference (HC) was measured as the maximum occipito-frontal circumference using a non-stretchable tape measure.Weight,lengthandHCweremeasuredaccordingto themethodsrecommendedbyWHO1995[24].Measurements weretakentwice,bytwodifferentoperatorsandthemeanof eachwasnoted.Forinfantsbornpreterm, theanthropometric parametersandthemonthlynutritionalindiceswereconsidered accordingtothegestation-adjustedageofinfants.Thez-scores weightforage(WAZ),heightforage(HAZ),weightforheight (WHZ) and HC for age (HCAZ) were used to define the nutritionalstatus of infants. Acutemalnutrition (emaciation), chronicmalnutrition(stunting)andunderweightweredefined according to the WHO 2006 criteria: for emaciation, a WHZ<2, and/or bilateralnutritional edema.Stunting was defined as a HAZ<2. Underweight was defined as the

Fig.1. FlowchartforinfantsfollowedinMCHU/RPGHB.MCHU:maternalandchildhealthunit;RPGHB:ReferenceProvincialGeneralHospitalofBukavu;LBW: lowbirthweight;SGA:smallforgestationalage;IUGR:intra-uterinegrowthretardation;FTNW:full-termandnormalweight.

WAZ<2[25,26].Assuggested byOngetal.[27],growth failurewasdefinedasadecreaseinweightz-scoreofover0.67 (i.e.over0.67SD)duringanyofstudyperiods.Aquestionnaire was also administered monthly to collect information about breastfeeding and to assess the quality of feeding practices throughaqualitative 24-hour dietaryrecall, according tothe WHOrecommendations[28,29].

2.4.3. Ethicalconsiderations

Thestudywasexplainedtowomenpreviouslyduringtheir stayinneonatologyunitandinthematernity.Ethicalapproval was granted by the Ethical Committee of the Catholic University of Bukavu, DRC. In order to guarantee the confidentiality of the information given by the participants inthe study,datawerereviewedandanalyzedanonymously. 2.5. Statisticalanalysis

ThedatawereanalyzedusingSPSSsoftwareversion20.The nutritional indices WAZ, HAZ, HCAZ and WHZ were computedwiththesoftwareEpinut,version3.3.2(Centerfor Disease Control and Prevention, Atlanta) and WHO Anthro 2005.Proportionswerecomparedbyusingeitherthex2orthe Fisherexacttest.ThenonparametricKruskall–Wallistestwas used for the comparison of quantitative variables. Logistic regressionwasusedtoquantifytheassociationbetweengrowth failure and sociodemographic and nutritional factors in multivariate analysis. Incidence rate ratios (IRR) and their 95%confidenceintervals(95%CI)werecomputedbyusingthe groupinwhichtheincidencewasthelowestasreference.The statisticalsignificancethresholdwasfixedat0.05.

3. Results

The characteristics of all mothersand infantsare summa-rized in Table 1. During the overall follow-up of the 200mother–child pairs, 5144WAZ, HAZ, HCAZandWHZ valueswerecomputed.TherateofmissingWAZ,HAZ,HCAZ andWHZdatawas0.29%tothefirstmonthto20%atthe6th month.

Growthmeasurementsatthevarioustimepointsofthestudy aresummarizedinTable2.Duringtheentirefollow-upperiod, meanz-scoresforWAZandHAZremainednegativeatalltime pointsalong the lineof usual progression according toage, indicating that children in this population were restricted in growth and stunted compared with the reference population (WHO2006).Meanz-scoresforWHZremainednegativefrom birth to 3 months of life (or adjusted age), indicating that children were thinner than the reference population (WHO 2006) during that period. At 6 months of life (or gestation-adjustedage),theprevalencesofunderweight,stuntedgrowth andemaciationwere,respectively,22.3%(15.3%forLBWand 7%fornoLBW),64.3%(51.4%forLBW13%fornoLBW) and7.2%(4.2%forLBW and3%fornoLBW).Eighteen(25%) LBWinfantshadalowHCforage.

Theprogressionofgrowthfailureatthevarioustimepoints ofthestudyissummarizedinFig.2.Seventeen(17%,or17of

100) LBW infants exhibited growth failure during the first month,4(4.9%,or4of81)duringthe3rdmonthand1(1.4%, or 1 of 72) during the 6th month. Forno LBW infants, the prevalenceofgrowthfailurewas24% thefirstmonthand3% the6th month.

Nutritionalcharacteristicsofthe200mother–childpairsare summarized in Table 3. The prevalence of exclusive

Table1

Baselinecharacteristicsofthe200mother-childpairsfollowedintheMCHU/ RPGHBfromJanuarytoDecember2016.

LBW n(%)

NoLBW n(%) Maternalage(inyears)[Median

(min–max)] 25(16–40) 27(16–45) <18 2(2) 1(1) 18–35 94(94) 88(88) 35 4(4) 11(11) Maritalstatus Married 96(96) 95(95) Unmarried 4(4) 5(5)

Parity[Median(min–max)] 2(1–7) 3(1–8)

Primipara 42(42) 34(34)

Multipara 58(58) 66(66)

Mother’sschoolingstatus

Unschooled 5(5) 3(3) Primaryschool 10(10) 14(14) Secondaryschool 42(42) 33(33) Universityschool 43(43) 50(50) Socioeconomicstatus Low 41(41) 29(29) Medium 33(33) 24(24) Good 26(26) 47(47)

Interpregnancyinterval[Median (min–max)]

34(11–108) 18(14–106) <24months 20/58(34.5) 26/65(40)

24months 38/58(65.5) 39/65(60)

Siblingsize[Median(min–max)] 2(1–7) 2(1–11)

<5 93(93) 80(80) 5 7(7) 20(20) Sex Male 52(52) 58(58) Female 48(48) 42(42) Typesofnewborns Preterminfants 74(74) 0

Fullterminfants 26(26) 100(100)

NoIUGR 67(67) 100(100)

IUGR 33(33) 0

AsymmetricalIUGR 7(21.2) 0

SymmetricalIUGR 26(78.8) 0

Birthanthropometricparameters Birthweight(ingrams) [Mean SD]

1997.2 411 3290.4 327 Birthlength(incm)[Mean SD] 43.3 3.7 50.2 1.6 Birthheadcircumference(incm)

[Mean SD]

30.9 1.9 35.0 0.9 MeandailyweightgainandMedian

lengthofstay

Meandailyweightgain(ing/kg/ day)[Median(min–max)]

17(5–31) 22.7(10–33.3) Medianlengthofstay(indays)

[Median(min–max)]

11(2–69) 3(1–5)

MCHU:maternalandchildhealthunit;RPGHB:ReferenceProvincialGeneral Hospitalof Bukavu; LBW:Lowbirthweight; IUGR: Intra-uterinegrowth retardation.

R.Mbusa-Kambaleetal./Revued’E´ pide´miologieetdeSante´ Publique66(2018)245–253 248

Growth measurements and outcomes.

Study time points

Birth 1 month of life (or corrected age) 2 months of life (or corrected age) 3 months of life (or corrected age) 4 months of life (or corrected age) 5 months of life (or corrected age) 6 months of life (or corrected age) LBW (n = 100) No LBW (n = 100) LBW (n = 96) No LBW (n = 100) LBW (n = 84) No LBW (n = 100) LBW (n = 81) No LBW (n = 100) LBW (n = 80) No LBW (n = 100) LBW (n = 73) No LBW (n = 100) LBW (n = 72) No LBW (n = 72) Weight Mean (kg) (SD) 1.9 (0.4) 3.3 (0) 2.9 (0.7) 4.4 (0.5) 3.9 (0.8) 5.3 (0.7) 4.8 (0.8) 6.0 (0.8) 5.5 (0.7) 6.6 (1) 6.1 (0.7) 7.1 (0.9) 6.7 (0.7) 7.6 (1) Mean z score (SD) 3.1 (1.12) 0.04 (0.70) 2.80 (1.32) 0.02 (0.83) 2.42 (1.47) 0.26 (1.05) 2.09 (1.33) 0.22 (1.09) 1.70 (1.17) 0.27 (1.05) 1.40 (1.14) 0.24 (1.08) 1.07 (1.97) 0.29 (1.12) WAZ <2, n (%) 79 (79) 1 (1) 67 (69.8) 0 52 (61.9) 5 (5) 44 (54.3) 7 (7) 32 (40) 6 (6) 19 (26) 6 (6) 11 (15.3) 7 (7) Height Mean (cm) (SD) 43.3 (3.6) 50.2 (1.6) 49.1 (3.9) 53.9 (1.9) 52.4 (3.7) 56.6 (2.1) 55.3 (3.4) 59.1 (2.3) 57.8 (3.9) 61.5 (2.3) 59.8 (4.0) 63.6 (2.4) 61.9 (4.1) 65.6 (2.6) Mean z score (SD) 2.99 (1.51) 0.36 (0.84) 2.94 (1.54) 0.15 (0.94) 2.74 (1.65) 0.65 (1.05) 2.50 (1.48) 0.76 (1.10) 2.33 (1.45) 0.81 (1.07) 2.14 (1.37) 0.73 (1.12) 2.04 (1.43) 0.62 (1.18) HAZ <2, n (%) 74 (74) 2 (2) 55 (58.5) 0 53 (63.1) 13 (13) 50 (61.7) 16 (16) 44 (55) 17 (17) 37 (50.7) 13 (13) 37 (51.4) 13 (13) Head circumference Mean (cm) (SD) 30.9 (1.9) 35.0 (0.9) 34.4 (1.9) 37.3 (0.9) 36.4 (1.9) 38.7 (1.2) 38.1 (1.8) 40.0 (1.4) 39.4 (1.8) 41.2 (1.5) 40.5 (1.7) 42.5 (1.5) 41.8 (1.8) 43.5 (1.6) Mean z score (SD) 2.7 (1.54) 0.7 (0.8) 2.0 (1.52) 0.2 (0.87) 2.2 (1.57) 0.3 (1.02) 1.8 (1.56) 0.3 (1.19) 1.5 (1.42) 0.1 (1.22) 1.3 (1.4) 0.08 (1.24) 0.8 (1.34) 0.3 (1.23) HCAZ <2, n (%) 63 (63) 0 49 (51.0) 0 37 (44.0) 0 34 (42.5) 7 (7) 31 (38.8) 8 (8) 27 (37.5) 7 (7) 18 (25) 4 (4)

Weight for height

Mean z score (SD) 1.84 (1.26) 0.41 (1.0) 1.15 (1.54) 0.35 (1.31) 0.11 (1.61) 0.67 (1.40) 0.38 (1.36) 0.58 (1.45) 0.53 (1.14) 0.38 (1.07) 0.60 (1.21) 0.23 (1.40) 0.65 (1.20) 0.04 (1.35)

WHZ <2, n (%) 80 (80) 7 (7) 40 (42.6) 9 (9) 15 (17.9) 8 (8) 7 (8.6) 10 (10) 6 (7.5) 6 (6) 6 (8.2) 5 (5) 3 (4.2) 3 (3)

LBW: low birth weight; WAZ: weight for age z-score; HAZ: height for age z-score; HCAZ: head circumference for age z-score; WHZ: weight for height z-score.

R. Mb usa-Kambale et al. / Re vue d’E ´ pide ´miologie et de Sante ´ Publique 66 (2018) 245 – 253 249

breastfeedingwas72%forLBWinfantsand63%fornoLBW infants.Seventeen(60.7%,or17of28)infantswerefedwith preterm formula and breastfeeding. The mean age of introducing complementary food was 4.5 months for LBW infants and 5 months for no LBW infants. All mothers continuedbreastfeedingafter6 months.

Table4summarizestheriskfactorsassociatedwithgrowth failure. In multivariate analysis, only male sex (OR=1.56[95%CI:1.03–2.23])wasassociatedwiththerisk ofgrowthfailure.ThesymmetricalIUGRwasaprotectorfactor ofgrowthfailure(OR=0.49[95% CI:0.25–0.98]).

4. Discussion

The main objective of this study was to evaluate the evolution of anthropometric parameters and the nutritional statusofLBWinfantsandtoanalyzefactorsinfluencinggrowth failureduringtheirfirst6monthsoflife.At6monthsoflife(or

adjustedage),15.3%ofLBWinfantswereunderweight,51.4% werestuntedand4.2%exhibitedemaciation.Malegenderwas significantlyassociatedwithgrowthfailure.Wedidnotfindany associationbetweenLBWinfantdietandgrowthfailure.

In a retrospective study of 24,371 preterm infants in the USA, Clark et al.[30]reported stunting (34%), underweight (28%),andalowHCforage(16%).Anotherstudycarriedout inIsraelbyMarksetal.[31]andinvolving5977preterminfants reportedthat10.6%wereunderweight.Highratesofpost-natal stuntingandunderweighthavebeenreportedmostlyinAfrica and Asia. In Senegal, Faye et al. [32] reported extra-uterine growth retardation (86%), underweight (61%), and under-weightat40weekspost-conception(41%),at3monthsandat 6 months of gestation-adjusted age. Other higher rates of underweightwerereportedinMorocco(77.5%)[33],Tunisia (55%)[34],China(56.8%)[35]andJapan(49%) [36].

In the medium term, nutritional disturbances are also of interesttoinfantswithahistoryofIUGR.InNigeria,Olusanya etal.[37],inacross-sectionalsurveytoassess theimpactof IUGR on growth atoneweekof life, showed an association betweenIUGRandnutritionaldisturbances,resultsconfirmed laterinthissamecohortattheageof3months[38].Comparable resultsonvariousanthropometricindiceshavebeendescribed inKenya[39],Ethiopia[40]andMalawi[41].

Inourreport,chronicmalnutritionseemstobemuchmore importantthanacutemalnutritionandthiscouldbeconsidered asacriterionforthevalidityofourdata.However,theseresults areworrisome becausetheyseemtoindicatethatwithintwo years, more than half of the population shows growth disturbances. This is consistent with the demographic and health survey (DHS) of DRC-2014 showing, in South Kivu province,achronic malnutritionrateof 53%amongchildren under5(thehighestintheDRC).Sizegrowthisamorerobust measurebecauseitevolvescumulativelyuntiltheageof2years andthenstabilizesinplateau. Weightisalabilemeasurethat peaks between 12 and 18 months. Acute malnutrition is therefore a condition that can vary rapidly over time and is highly dependentonthe child’shealthor alimitedperiod of nutritionaldeprivation.

The rateof exclusive breastfeeding inour study ishigher thanthe nationalrate. According tothe DHS-DRC, in2014,

Table3

Nutritional characteristics of the 200 mother–child pairs followed in the MCHU/RPGHBfromJanuarytoDecember2016.

LBW n(%)

NoLBW n(%) Exclusivebreastfeeding(Mean SD) 4.5 1.1 5.2 1.6

Until6months 72(72) 63(63)

Under6months 28(28) 37(37)

Complementaryfood n=28 n=37

Pretermformula 17(60.7) 0

Firstinfantformula 11(39.3) 18(48.7)

Protein-enrichedporridge 0 16(43.2)

Nonprotein-enrichedporridge 0 1(2.7)

Solidorsemi-solidfoods 0 2(5.4)

Causesofexclusivebreastfeedingunder6months n=31 n=37 Lowbreastmilkproduction 22(70.9) 11(29.8)

Goingbacktowork 5(16.1) 13(35.1)

Thebabywasnotsatisfiedbybreastmilk 3(9.7) 4(10.8)

Mastitis 1(3.3) 3(8.1)

Ididnotknowthemomentofdietarydiversity 0 6(16.2) Continuedbreastfeeding 100(100) 100(100) MCHU:Maternalandchildhealthunit;RPGHB:ReferenceProvincialGeneral HospitalofBukavu.

Fig.2. Evolutionofgrowthfailureatthevarioustimepointsofthestudy.LBW:lowbirthweight;NoLBW:nolowbirthweight;M:month. R.Mbusa-Kambaleetal./Revued’E´ pide´miologieetdeSante´ Publique66(2018)245–253

48% of children under 6 months of age were exclusively breastfed.The practice of exclusive breastfeedingduring the firstsixmonthsisinagrowingtrend,withanestimated24%in 2001,36% in2007,37% in2010and48%in2014[10].

ManyfactorsinfluencethepostnatalgrowthofLBWinfants. Since 1948, nutritional practices have been identified as the main cause of the postnatal growth restriction observed in preterm infants [42]. This restriction of postnatal growth is explained by the highenergy requirements of these growing childrenandneonatalpathologies[43].In2001,Embletonetal.

[44]demonstratedtheimportanceofthecumulativenutritional deficitthatoccursduringthefirstweeksoflife,stressingthatit does not subside during the hospitalstay of preterm infants. Basedonrecommendationsof 120kcal/kg/dwith3g/kg/dof protein,theauthorsdescribed,afteroneweekoflifeinpreterm infants of30 weeks, a cumulative nutritional deficit of 406 92kcal/kg and 14 3g/kg protein, corresponding to 48%and67%ofthetheoreticalcumulativeintakesofthefirst week, respectively. Other nutritional studiesin very preterm infantsconfirmedthattheyaccumulateamajorprotein-energy deficiencyduringthefirstweekoflife;thisdeficitpersistsandit is associated with severe postnatal growth restriction [45– 47].Thiscumulativedeficitofprotein-energyintakeduringthe firstfewweeksof lifeseemstoberesponsibleforhalf ofthe post-natal growth restriction observed in these very preterm infants[43]and,inparticular,proteindeficiencyinthefirstdays oflife[47,48].

BeingmaleisanotherriskfactorofimpairedgrowthinLBW infantsreportedinsomestudies.Indeed, Kaboreetal.[49]in Burkina Fasoand Kalandaet al.[50] inMalawi described a highprevalence ofstunting andunderweightinmale infants. SimilarobservationswerealsomadebyWamanietal.[51]in Uganda,VandePoeletal.[52]inGhana,Ukwuanietal.[53]in

Nigeria andMedhinet al.[40]in Ethiopia.Thisobservation was confirmed by a meta-analysis in 16 countries in sub-SaharanAfrica[54].Severalhypotheseshavebeenputforward to explain this growth differential between girls and boys: Medhinetal.[40]inEthiopiaandPadonouetal.[55]inBenin reported the high prevalenceof anemiaamong boys intheir study populationstoexplaintheirpoorgrowth.Well[56],on the otherhand,referredtothe hypothesisthatgeneticfactors could explain the relative vulnerability of boys to girls. Recently, Warrington et al.[57] demonstrated an interaction betweengeneticpolymorphismsandsex,indicatingthattheage atwhichgeneticgrowthdisordersoccur,differsbetweenboys andgirls.

OurreportdemonstratedthatthesymmetricalIUGRwasa protector factor of growth failure.Bocca-Tjeertes et al., ina study examining how symmetric growth restriction and asymmetric growthrestriction influencegrowth and develop-mentinpretermsfrombirthto4years,reportedthatuptoage 4years, symmetricgrowthrestrictionandasymmetricgrowth restrictionpreterm-bornchildrenfailedtocatchuponweight andheight sufficiently, andthatthesepretermchildren could not keep up with the growth velocity of their non–growth restrictioncounter-parts.But,ontheotherhand,theHCgrowth of symmetric growthrestrictionexceededthatof asymmetric growth restriction and non–growth restriction, but still remainedloweratage1year[58].

5. Conclusion

Thisstudyfocusedontheanalysisofthesomaticgrowthof LBWinfants,followedbetweenJanuaryandDecember2016in theMCHUofRPGHBinSouth-KivuProvinceineasternDRC. TheaimwastoevaluatenutritionalstatusofinfantsbornLBW

Table4

Comparisonofgrowthofinfantswithandwithoutgrowthfailure.

Growthfailure Nogrowthfailure AdjustedOR(95%CI) P-value Socioeconomicstatus Low 11(27.5) 29(72.5) 0.85(0.42–1.71) 0.65 Medium 11(32.4) 23(67.6) 1 Good 10(38.5) 16(61.5) 1.18(0.59–2.36) 0.62 Interpregnancyinterval <24months 23(37.1) 39(62.9) 1.56(0.81–3.01) 0.16 24months 9(23.7) 29(76.3) 1 Infantsex Male 18(37.5) 30(62.5) 1.56(1.03–2.33) 0.027 Female 14(26.9) 38(73.1) 1 Typeofnewborns Preterminfants 20(27.0) 54(73.0) 0.58(0.33–1.02) 0.07

Fullterminfants 12(46.2) 14(53.8) 1

IUGR 13(39.4) 20(60.6) 1.39(0.78–2.45) 0.27 NoIUGR 19(28.4) 48(71.6) 1 SymmetricalIUGR 1(14.3) 6(85.7) 0.31(0.04–0.9) 0.018 AsymmetricalIUGR 12(46.2) 14(53.8) Complementaryfood Exclusivebreastfeeding 23(31.8) 49(68.1) 0.90(0.43–1.87) 0.79

Firstinfantformula+breastfeeding 3(27.3) 8(72.7) 0.77(0.24–2.46) 0.41

Pretermformula+breastfeeding 6(35.3) 11(64.7) 1

andtoanalyzefactorsinfluencingtheirgrowthduringtheirfirst 6monthsoflife.Differentriskfactorsforimpairedgrowthof LBWinfantshavebeenidentified.Information,educationand communication for mothers about the importance of this follow-upcanbe helpful in rapidlydetecting andremedying thesegrowthproblems.In addition, otherlong-term research involvingtheaspectsofneurocognitivedevelopmentshouldbe carried out to ensure that these infants receive global and optimalcare.

Disclosureofinterest

The authorsdeclarethattheyhavenocompetinginterest. Acknowledgments

We thank the entire staff of the Pediatrics andObstetrics DepartmentsatRPGHBfortheirtechnicalassistance.Wealso gratefullyacknowledgethestudy’s participants.

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