Rev. paul. pediatr. vol.34 número4

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REVISTA

PAULISTA

DE

PEDIATRIA

www.rpped.com.br

REVIEW

ARTICLE

Effects

of

obesity

on

lung

volume

and

capacity

in

children

and

adolescents:

a

systematic

review

Aline

Dill

Winck

a

_,

_João

_Paulo

_{Heinzmann-Filho}

b,∗

,

Rafaela

Borges

Soares

b

,

Juliana

Severo

da

Silva

b

_,

_Cristhiele

_Taís

_Woszezenki

b

_,

_Letiane

_Bueno

_Zanatta

c

a_Universidade_de_Caxias_do_Sul_(UCS),_Caxias_do_Sul,_RS,_Brazil

b_Pontifícia_Universidade_Católica_do_Rio_Grande_do_Sul_(PUC-RS),_Porto_Alegre,_RS,_Brazil c_Instituto_Cenecista_de_Ensino_Superior_de_Santo_Ângelo_(Iesa),_Santo_Ângelo,_RS,_Brazil

Received4November2015;accepted28February2016 Availableonline25July2016

KEYWORDS

Lungfunctiontests; Lungvolume measurements; Total

plethysmography; Obesity;

Pediatrics

Abstract

Objective: Toassesstheeffectsofobesityonlungvolumeandcapacityinchildrenand adoles-cents.

Datasource: This is a systematic review, carried out inPubmed, Lilacs, Scielo and PEDro databases,usingthefollowingKeywords:Plethysmography;WholeBodyORLungVolume Mea-surementsORTotalLungCapacityORFunctionalResidualCapacityORResidualVolumeAND Obesity.Observational studiesor clinicaltrials thatassessed theeffectsofobesity onlung volumeandcapacity inchildren andadolescents(0---18 years)without anyotherassociated disease;inEnglish;PortugueseandSpanishlanguageswereselected.Methodologicalquality wasassessedbytheAgencyforHealthcareResearchandQuality.

Datasynthesis: Of the 1,030 articles, only four were included in the review. The studies amountedto548participants,predominantlymales,withsamplesizerangingfrom45to327 individuals.100%ofthestudiesevaluatednutritionalstatusthroughBMI(z-score)and50.0% reportedthedataonabdominalcircumference.Alldemonstratedthatobesitycausesnegative effectsonlungvolumeandcapacity,causingareductionmainlyinfunctionalresidualcapacity in75.0%ofthestudies;intheexpiratoryreservevolumein50.0%andintheresidualvolume in25.0%.Themethodologicalqualityrangedfrommoderatetohigh,with75.0%ofthestudies classifiedashavinghighmethodologicalquality.

Conclusions: Obesitycausesdeleteriouseffectsonlungvolumeandcapacityinchildrenand adolescents,mainlyby reducingfunctionalresidualcapacity,expiratoryreservevolumeand residualvolume.

∗_{Corresponding}_author.

E-mail:joaopauloheinzmann@hotmail.com(J.P.Heinzmann-Filho). http://dx.doi.org/10.1016/j.rppede.2016.03.013

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PALAVRAS-CHAVE

Testesdefunc¸ão pulmonar;

Medidasdevolume pulmonar;

Pletismografiatotal; Obesidade;

Pediatria

Efeitosdaobesidadesobreosvolumeseascapacidadespulmonaresemcrianc¸as eadolescentes:umarevisãosistemática

Resumo

Objetivo: Avaliarosefeitosdaobesidadesobreosvolumeseascapacidadespulmonaresem crianc¸aseadolescentes.

Fontesdedados: Trata-sede umarevisão sistemática,atravésdasbases dedadosPubmed, Lilacs,SciELOePEDro,pormeiodasseguintespalavras-chave:Plethysmography,WholeBody OR LungVolumeMeasurementsOR TotalLungCapacity ORFunctionalResidual CapacityOR ResidualVolumeANDObesity.Foramselecionadosestudosobservacionaisouensaiosclínicosque avaliaramosefeitosdaobesidadesobreosvolumeseascapacidadespulmonaresemcrianc¸ase adolescentes(0a18anos),semqualqueroutradoenc¸aassociada,nosidiomasinglês,português eespanhol.AqualidademetodológicafoiavaliadaatravésdaAgencyforHealthcareResearch andQuality.

Síntesedosdados: Dos1.030artigos,apenasquatroforamincluídosnestarevisão.Osestudos totalizaram548participantes,compredomíniodosexomasculinoetamanhoamostralentre45 e327indivíduos;100%dosestudosavaliaramoestadonutricionalatravésdoIMC(escore-z)e50% informaramosdadosdacircunferênciaabdominal.Todosdemonstraramqueaobesidadecausa efeitos negativossobre osvolumes eas capacidades pulmonares, causareduc¸ão, principal-mente,dacapacidaderesidualfuncionalem75%dosestudos,dovolumedereservaexpiratório em50%edovolumeresidualem25%.Aqualidademetodológicavariouentremoderadaealta, com75%dosestudosclassificadoscomaltaqualidademetodológica.

Conclusões: Aobesidadecausaefeitosdeletériossobreosvolumeseascapacidadespulmonares em crianc¸as eadolescentes, comreduc¸ãoprincipalmente dacapacidade residualfuncional, volumedereservaexpiratórioevolumeresidual.

Introduction

Childhoodobesityiscurrentlyamajorpublichealthproblem andincreasesatanalarmingrateintheworld’spopulation, includingtheBrazilianpopulation.1_It_is_estimated_that₁₅₀ millionadultsand15millionchildrenareobese.2_Recently, epidemiologicaldataindicatedthattheprevalenceof obe-sityin theUnited Statesisapproximately17% andaffects about 12.7 million children and adolescents.3 _In _Brazil, some studies show that the prevalence of obesity ranges from2.4to19.2%,affectingmoretheSouthandSoutheast regions.4

AccordingtotheWorldHealthOrganization,obesitycan bedefinedasanabnormalconditionofbodyfator excess fattissue,whichcausesdamagetotheindividual’shealth.1 Somesituationsorclinicalconditionsseemtobeassociated withitsdevelopment,suchassedentarylifestyle,asthma, diabetes,hypertension,cardiovascularandrespiratory dis-eases.Amongthese,therespiratorysystemdeservesspecial attention,asexcessweightbringsdirectchangesto venti-latorymechanics.1,5,6

Inrecentdecades,previousstudiessuggestedthat obe-sity causes a major change in the respiratory system, resulting in loss on thoracoabdominal synchronism.7 _The increaseinbodyweightcauseslimitationofdiaphragmatic mobility andreduced backmovement, withimpaired pul-monary gas exchange and breathing pattern control.7---10 Moreover,excessadiposetissueisassociatedwithincreased inflammatorymediatorsandcytokines,whichcouldalterthe

pulmonaryairwaysofthesesubjectsandcontributetothe developmentofbronchialhyperreactivity.11

Inadditiontotheabovementionedchanges,theresearch onthesubjectpointstothepresenceofimportantlung func-tionalterationsinchildrenandadolescentswithexcessfat, includingreducedforcedexpiratory volumein onesecond (FEV1), forced vital capacity (FVC) and forced expiratory flowbetween25and75%ofFVC(FEF25---75%).12,13

Asystematicreviewpublishedin201214_showed,_through acriticalanalysisoffivestudies,thatobesityleadstolosses mainly in FEV1 and FVC. However, this study only evalu-atedtheeffectsofbodyweightonspirometricvariables.14 Taking into account that the spirometry test directly investigates obstructive pulmonary parameters and that the obesity factor seems to affect more the restrictive pattern,1,5 _the _importance _of _{investigating,} _through ple-thysmography, the effects of body mass on lung volume andcapacityinchildrenisemphasized.Moreover,todate, the results are contradictory in terms of the impact of obesityonthesepulmonary outcomesin samplesofyoung individuals.15

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Method

Thestudyconsistsofasystematicreviewcarriedoutthrough asearchinthePubMed,Lilacs,SciELOandPEDrodatabases. Observational studies and clinical trials were selected in English,PortugueseandSpanish,withoutanyfiltersforage andyearofpublicationofthearticles.Theperiodofstudy selectionwasfromSeptembertoOctober2015.

Thesearchusedfor theselection ofarticleswasbased onsixkeywords associatedwithBooleandescriptors.The followingstrategywasused:plethysmography,wholebody ORlung volume measurementsOR total lung capacityOR functionalresidualcapacityORresidualvolumeANDobesity. Thesedescriptorsshouldbe includedat least inthe title, abstractorinthekeywords.

Studiesthatevaluatedlungfunctionbyplethysmography inobesechildrenandadolescents(0---18years)wereusedas inclusioncriteria.Obesitywasdefinedasbodymass index (BMI)z-score values>+2or≥97thpercentile.On theother hand, review studies, case reports, articles that did not assesslung volumeand capacitythroughbody plethysmo-graphy,studies that assessedrespiratory function through otherevaluationmethods ordidnotnormalizetheresults ofpulmonary function(plethysmography)in z-scores, per-centageofpredictedortheonesthatdidnotcomparethe results with those from a control group were excluded. Studies evaluatingthe adultage group or did notinclude onlychildrenandadolescentswerealsoexcluded.Moreover, studieswithsubjectswithanyotherchronicdiseaseswere excluded.

After identifying the descriptors in the title, abstract and/or keywords, the abstracts of selected articles were readtoassesstheadequacyaccordingtotheeligibility crite-ria.Studiesthatmetthepredeterminedcriteriahadthefull text read for detailed analysis and data extraction. Arti-clesearchandanalysis,according totheabovementioned strategywerecarriedoutindependentlybytworeviewers anddisagreementswereresolvedwithathirdreviewer,by consensus.

The following characteristics of the studies were recorded: first author’s name, year of publication of the study,country(source)ofdatacollection,agerange,sample size,bodymass index(BMI),waistcircumference, plethy-smography equipment, methodology used, type of data presentation (z-score, percentage of predicted or liters), assessed plethysmographic variables [expiratory reserve volume(ERV),inspiratoryreservevolume(IRV),residual vol-ume(RV),functionalresidualcapacity(FRC),vitalcapacity (VC),inspiratorycapacity(IC)andtotallungcapacity(TLC)], extrapulmonarytests, mainplethysmographic resultsand additionalresults.

Methodological quality was assessed by two reviewers andanydivergenceswereresolvedbyconsensus.An appro-priate scale for observational studies by the Agency for HealthCareResearchandQuality(AHRQ)wasused.16 _This tool evaluates nine items related to the study subject, methodologicalaspects, consistency of results, discussion andsponsorship.Thefinalsumofeachevaluateditemtotals a score of 100, with the studies being classified as low (<50points),moderate(50---66points)andhigh(>66points) methodologicalquality.

Results

Atotalof1030articleswereidentified,808inPubmed,218 inLilacs,twoinSciELOandtwoinPEDro.Ofthese,199were excludedforbeingrepeatedintheassesseddatabasesand 827becausetheydidnotmeettheeligibilitycriteriaofthis review.Thus,onlyfourstudieswereincluded,which eval-uatedthe effects ofobesity onlung volume andcapacity inchildrenandadolescentsthroughbodyplethysmography.

Fig.1showsaflowchartrelatedtothetotalnumberof arti-clesfoundintheassesseddatabasesandreasonsfor study exclusion.

Theselectedstudiestotaledasampleof548participants, withaprevalenceof296(54%)ofmaleindividuals.The sam-plesizeofthestudiesvariedgreatly,rangingfrom45to327 subjects.Theageoftheselectedparticipantsrangedfrom 6 to18.9 years.Allstudies evaluatedBMI throughz-score andtwo(50%)reporteddatafromthewaistcircumference. Of the fourstudies, two were carriedout in Asia, one in AmericaandoneinEurope(Table1).

Regardingthecharacteristicsof theequipmentusedto measure lung volume and capacity by plethysmography, three(75%) studiesusedthe SensorMedics equipmentand onlyoneusedaJaegerdevice.Ofthestudies,three(75%) followedtherecommendationsofinternationalguidelines, while one did notreport themethodology usedto obtain the pulmonary data. All studies included normalized the findingsonlungvolumeandcapacitythroughthe percent-ageof predicted,althoughonlyone(25%)evaluatedsome plethysmographicvariablesinabsolutevalues(liters). Addi-tionally,allofthemmeasuredspirometricvariablesand50% measuredthecarbonmonoxidediffusion(DLCO).

The assessed plethysmographic data included VC, ERV, RV,FRCandTLC.Allstudiesshowedthatobesityhasa neg-ative effectonlung volumeandcapacity,mainly reduced FRCin75%ofstudies,ofERVin50%andRVin25%.Overall, thestudieshavealsotestedtheassociationsofventilatory variables and outcomes relatedto obesity,including BMI, waist circumference, fat mass index and waist-to-height ratio(Table2).

Finally, regarding the methodological quality of the selectedarticles(Table3),theaveragescorewas71points, rangingbetween63and83.Ofthese,one(25%)studyhad a scorecompatiblewithmoderate methodologicalquality and three(75%) withhigh quality,according tothe AHRQ scale.Factorsthatloweredthequalityscoreoftheselected studieswereassociatedtoitemsrelatedtothestudy pop-ulation, comparison of subjects, outcome measurement, statistical analysis, discussion of data and informationon supportand/orfundingofthestudy.Itisnoteworthythatof thefourstudies,only onehadjustificationforthesample size,aswellasreportedinformationonblindingregarding whenassessing theresults.Furthermore,only twostudies reportedresearchsupportandfunding,noneof them cal-culated the power of analysis, as well as how potential confoundersandresultbiaseswereassessed.

Discussion

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Pubmed (n=808)

Identification

Included

Eligibility criteria

Lilacs (n=218)

Total of studies (n=1030)

Excluded repeated studies (n=199)

Excluded studies (n=827) Assessed studies

(n=831) Reasons for exclusion 298 studies in adults 225 did not assess volumes

189 associated diseases

75 reviews 26 experimental studies

10 case reports

4 without access to article

Included studies (n=4)

Scielo (n=2)

PEDro (n=2)

Figure1 Flowchartofthetotalnumberofarticlesfoundinthedatabases.

Table1 Identificationandcharacteristicsofthestudiesincludedinthisreview.

Firstauthor Year Country Agerange

(years)

Sample size

BMI(z-score) WaistCircumference

Davidsonetal.17 ₂₀₁₄ _Canada _6---17 ₃₂₇ _2.18_±_0.41 _NA

vandeGriendtetal.18 ₂₀₁₂ _The_Netherlands _8.5---18.9 ₁₁₂ _3.38_±_0.40_{(2.50---4.62)} _122.2_±_15.7

Lietal.19 ₂₀₀₃ _China _7---18 ₆₄ _2.42_{(2.13---2.66)} _NA

Kongkiattikuletal.20 ₂₀₁₅ _Thailand _8.6---17.3 ₄₅ _3.2_±_0.5_(1.9---4.6) _99.1_±_10.4_(81---134)

BMI,bodymassindex;NA,informationnotavailable.

effectsofobesityonlungvolumeandcapacityinchildren andadolescents.17---20_The_findings_showed_a_reduction_mainly in FRC, ERV and RV, indicating negative effects of excess bodyweightonthesepulmonaryoutcomes.

Studies carried out in obese individuals with no associated comorbidities indicate that the increase in adipose tissue in the chest and abdomen area causes an increase in the intra-abdominal pressure, with con-sequent reduction in lung compliance and chest wall mobility.14,15

Thesealterationsresultinthoracoabdominalasynchrony, lead to diaphragmatic contraction impairment due to increasedloadontheabdomenandalsoimpairtheincrease inchestdiameterthroughthemovementoftheribs.Some findingssuggestthattheincreasedbodymassisassociated withhighertensilestrengthanddecreaseddistensibilityof extrapulmonarystructures.15,21

Under normal physiological conditions, the FRC is the pointofbalanceofelasticretractionsbetweenthelungand thechestwall.22_Thus,_whereas_FRC_is_the_sum_of_RV_and_ERV, anychangeintheseventilatoryvariablesimpliesinchanges ofthispointofbalance,asdemonstratedbyDavidsonetal.17 Changesinpulmonarybellowscausereducedlungvolumes, withsubsequentestablishmentofarestrictivepattern.23,24 Kongkiattikuletal.20_also_reported_that_the_reduction_of_FRC leadstoincreasedairresistance,peripheralvascular resis-tanceandimpairsalveolarventilation.Furthermore,these datasuggestthatphysiologicalchangesincreasetheriskof atelectasisandhypoxiainobeseindividuals.20,25_A system-aticreviewcarriedout intheobeseadult populationalso showedreductionofthesameplethysmographicvariables, withtheadditionofTLCandVC.15

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Table2 Characteristicsandmainresultsofthestudiesincludedinthisreview.

Typeof equipment

Methodology used

Data pre-sentation

Plethysmographic variables

Additional pulmonary tests

Main plethys-mographic results

Additionalresults

SensorMedics

620017

American Thoracic Society (ATS)

%ofpredicted andinliters*

TLC,VC*,FRC*, ERV*,RV*

Spirometry DLCO

Mean reductionof 0.44ofFRC, 0.22ofERV and0.20of RV

Reductionof FEV1/FVC(p<0.001). Positivelinear associationbetween BMIandFVC (p<0.001)andDLCO (p=0.015)

Negativelinear associationbetween BMIandFRC (p<0.001),ERV (p<0.001),RV (p<0,001)and FEV1/FVC(p<0.001). JaegerViasys18 _NA _%_of_predicted _TLC,_ERV,_VC _Spirometry _Mean

reductionof 14.3%inERV

Increaseof2.91% (p=0.002)ofFEV1, 3.08%(p=0.001)of FVC,2.27%(p=0.001) ofTLC,14.8% (p<0.001)ofERV afterreductionin bodyweight. Negativecorrelations oftheincreaseinERV withBMI(r=−0.27; p=0.01)andWC (r=−0.34;p=0.002). SensorMedics

620019

British Thoracic Society

%ofpredicted TLC,RV,FRC Spirometry DLCO

Mean reductionof 7%inFRC

Reductionof23.5%in DLCO.Negative correlationswith subtotalbodyand trunkfat,

respectively,of:FRC (r=---0.367;p<0.01; r=−0.337;p<0.01), RV(r=−0.298; p<0.05;r=−0.290; p<0.05),TLC (r=−0.268;p<0.05; r=−0.264;p<0.05). SensorMedics

620020

European Respiratory Society (ERS)

%ofpredicted TLC,FRC,RV Spirometry Mean reductionof 33.1%inFRC

Negativecorrelations betweenFRCwith BMI(r=−0.32; p=0.03),waist-height ratio(r=−0.32; p=0.02),%bodyfat (r=−0.32;p=0.03),% fatintrunk(r=−0.32; p=0.04)andFMI (r=−0.36;p=0.02).

%,Percentage;VC,vitalcapacity;TLC,totallungcapacity; FRC,functionalresidual capacity;RV,residual volume,ERV, expiratory

reservevolume;FEV1,forcedexpiratoryvolumeinonesecond;FVC,forcedvitalcapacity;DLCO,carbonmonoxidediffusioncapacity;

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Table3 Assessmentofthemethodologicalqualityofthestudiesincludedinthesystematicreview.

Criteriaassessed Referencescore Davidsonetal.17 _van_de_Griendt_et_al.18 _Li_et_al.19 _{Kongkiattikul}_et_al.20

Questionofthestudy 2 2 2 2 2

Studypopulation 8 5 5 5 8

Comparabilityof individualsforthe observationalstudies

22 16 14 11 11

Exposureorintervention 11 11 11 11 11

OutcomeMeasures 20 20 15 15 15

StatisticalAnalysis 19 12 9 7 7

Results 8 8 8 8 8

Discussion 5 4 3 4 4

Fundingandsponsorship 5 5 0 0 5

Totalscore 100 83 67 63 71

continents.17,18 _To_date,_no_study_was_found _carried_out_in the Brazilian pediatric population that aimed to evaluate theinfluenceofobesityonlungvolumeandcapacity. Per-hapsthislackofinformationatthenationallevelisbecause therearefewbodyplethysmographsinthecountry,aswell asthehighcostoftheequipmentandalsothefactthatitis hardertoobtainasatisfactorytestinapediatricsample.26 MoststudiesusedSensorMedicsequipment17,19,20_and_all_of them normalized of lung volumeresults through the per-centageof predicted,17---20 _although _a_study_did _not_report theequationused.18

Of the included studies, three followed international guidelinesforbodyplethysmography,includingthe Ameri-canThoracicSociety,EuropeanRespiratorySocietyandthe BritishThoracicSociety.17,19,20_In_general,_the_methods_used seemtoincludethesameventilatorymaneuverstoobtain lung volume and capacity, which contributes to greater externalvalidityoftheresults.

Recently, a systematic review showed the negative effectsofchildhoodobesityonspirometricvariables, indi-catedareductioninFEV1,FVCandFEV1/FVCratio.However, this study did not investigate the effects of the obesity factor onlung volumeandcapacity.14 _Taking_into_account thatobesitymaybeconsideredadiseasewitharestrictive pattern,1,5_the_data_shown_here_add_important_information about the impact of the disease onchildren’s respiratory system, compared to the study published in 2012.14 _It _is expectedthatfutureresearch,particularlyatthenational level,bedesignedtoassesstheeffectsofthischronic condi-tiononthepulmonarysystem.However,weemphasizethe importancethatnewstudiesstratifytheiragegroups (chil-drenandadolescents),toinvestigatethepossibleinfluence ofmaturationalstateontheseoutcomes.

Moreover,itbecomesessentialtodividethesesubjects astodifferentdegreesofobesity,asinthepresentreview it was not possible to assess the influence of these fac-tors. Although it is possible to evaluate the body mass of childrenand adolescentsthroughseveralmethods, BMI quantificationstands out asa simple and low-cost tool.27 Itis alsoknownthatnormalization usingpercentilesor z-scoresisessentialforabetterassessmentofthenutritional statusofthepediatricpopulation.27,28 _All_studies_included in thisreview evaluatedBMIthroughz-scores,which isin accordancewithpediatricrecommendations.27,28_Of_these,

two studies17,20 _showed _the _negative _influence _of _BMI _on FRC, ERV and RV through correlation testing and regres-sionmodels.Theseresultssuggestthatthehigherthebody composition,thelowerthelungvolumeandcapacity. Fur-thermore,previousstudieshaveshownnegativecorrelation betweenBMIandspirometricvariables,includingFEV1,FVC, FEF25---75%andFEV1/FVCratio.10,17,20,29Thesefindingssupport thehypothesisthatincreasedbodymasscauselimitationin diaphragmaticmobility,reductionofcostalmovement,and impairspulmonaryphysiology.7,10 _Griendt_et_al.,18 demon-stratedthatbodyweightreductionisrelatedtosignificant improvements in FEV1,FVC, TLC and ERV, indicating that theBMIreductioncontributestotheincreaseinthese out-comes.The authorsexplain these results due tothe fact that,byreducingbodyweight,oneincreasesthethoracic compartment space and improves lung compliance, thus facilitatingventilatorymechanics.Thecorrelationbetween theincreaseinERVanddecreasedwaistcircumference sup-portsthisrationale.18

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18.9years)withsevereobesity,weighingbetween52.3and 192.2kg.

Overall, the quality of the selected studies was high, ranging between moderate19 _and _high _{methodological} quality.17,18,20_For_this_evaluation,_we_used_a_modified_scale to quantify observational studies.16 _This _scale _has _shown to be adequate for this type of design14 _and _evaluates theresearchquestion, thestudypopulation, the compari-sonofparticipants,exposuremeasures,statisticalanalysis, results,discussionandfunding.16_The_studies_included_in_this reviewseemtohavesomelimitations,althoughitisbelieved thatsuchrestrictionsdidnotinfluencetheassessedresearch question,consideringthegoodmethodologicalqualitythat wasattained.

Some factorsloweredthe qualityscore of thestudies, suchas the absenceof sample calculation17---19 _the _power of analysis,17---19 _the _information _regarding _blinding _in _the quantificationofresults,18---20_the_care_regarding_the_possible confoundingvariables17---20 _and_the_impact_of_biases_on_the results.17---20 _As _most_of _the_studies _included _in _the_review hadacross-sectional design,17,19,20 _none _of _them_assessed subjects for a period of follow-up, except for the study ofvandeGriendtetal.,18 _which_analyzed _the_effect_of_a weightreduction programonpulmonary function parame-tersinobesechildrenandadolescents.Additionally,noneof thestudiesevaluatedtheeffectsofdose-responseandfew carriedoutmultivariatemodelsoranalyses,multiple com-parisontests17,18,20 _and _reported_funding _of _the _study.17,20 Theabovementioneditemsdirectlycollaboratedtoreduce thescoreintheassessedstudies.

In summary, the findings of this review demonstrate thedeleteriouseffectsof obesity onthe lungvolumeand capacityinchildren andadolescents,reducing mainlythe functionalresidualcapacity,expiratoryreservevolumeand residual volume. The results highlight the need to cre-atestrategiceffectivemeasurestofightchildhoodobesity throughintervention programstoprevent or mitigatethe negativeimpactofobesityonlungfunctioninthis popula-tion.

Funding

Thisstudydidnotreceivefunding.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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