www.jped.com.br
ORIGINAL
ARTICLE
Association
between
electronic
equipment
in
the
bedroom
and
sedentary
lifestyle,
physical
activity,
and
body
mass
index
of
children
夽
Gerson
Luis
de
Moraes
Ferrari
a,b,∗,
Timóteo
Leandro
Araújo
a,
Luis
Carlos
Oliveira
a,
Victor
Matsudo
a,
Mauro
Fisberg
baCentrodeEstudosdoLaboratóriodeAptidãoFísicadeSãoCaetanodoSul(CELAFISCS),SãoCaetanodoSul,SP,Brazil bCentrodeAtendimentoeApoioaoAdolescente(CAAA),DepartmentofPediatrics,EscolaPaulistadeMedicina(EPM),
UniversidadeFederaldeSãoPaulo(UNIFESP),SãoPaulo,SP,Brazil
Received13October2014;accepted28January2015 Availableonline27June2015
KEYWORDS
Physicalactivity; Sedentarylifestyle; Obesity;
Children
Abstract
Objective: Todescribetheassociationbetweenelectronicdevicesinthebedroomwith seden-tarytimeandphysicalactivity,bothassessedbyaccelerometry,inadditiontobodymassindex inchildrenfromSãoCaetanodoSul.
Methods: Thesampleconsistedof441children.Thepresenceofelectronicequipment (televi-sion,personalcomputer,andvideogames)inthebedroomwasassessedbyaquestionnaire.For sevenconsecutivedays,childrenusedanaccelerometertoobjectivelymonitorthesedentary timeandmoderate-to-vigorousphysicalactivity.Bodymassindexwascategorizedassuggested bytheWorldHealthOrganization.
Results: Overall,73.9%,54.2%and42.8%ofchildrenhadTV,computer,andvideogamesinthe bedroom,respectively,andspentanaverageof500.7and59.1min/dayofsedentarytimeand moderate-to-vigorousphysicalactivity.Ofthechildren, 45.3%wereoverweight/obese. Girls withacomputerinthebedroom(45min/day)performedlessmoderate-to-vigorousphysical activitythanthosewithoutit(51.4min/day).Similarresultswereobservedforbodymassindex inboys.Moderate-to-vigorousphysicalactivitywashigherandbodymassindexwaslowerin childrenthathadnoelectronicequipmentinthebedroom.Presenceofacomputer(ˇ=−4.798)
andthecombination TV+computer(ˇ=−3.233) werenegativelyassociated with
moderate-to-vigorousphysicalactivity.Videogamesandthecombinationswithtwoorthreeelectronic deviceswerepositivelyassociatedwithbodymassindex.Sedentarytimewasnotassociated withelectronicequipment.
夽
Pleasecitethisarticleas:FerrariGL,AraújoTL,OliveiraLC,MatsudoV,FisbergM.Associationbetweenelectronicequipmentinthe bedroomandsedentarylifestyle,physicalactivity,andbodymassindexofchildren.JPediatr(RioJ).2015;91:574---82.
∗Correspondingauthor.
E-mail:[email protected](G.L.d.M.Ferrari).
http://dx.doi.org/10.1016/j.jped.2015.01.009
Electronicequipment,sedentarylifestyle,physicalactivity,andBMI 575
Conclusion: Electronicequipmentinthechildren’sbedroomcannegativelyaffect moderate-to-vigorousphysicalactivityandbodymassindexregardlessofgender,school,andannualfamily income,whichcancontributetophysicalinactivityandchildhoodobesity.
©2015SociedadeBrasileiradePediatria.PublishedbyElsevierEditoraLtda.Allrightsreserved.
PALAVRAS-CHAVE
Atividadefísica; Sedentarismo; Obesidade; Crianc¸as
Associac¸ãoentreequipamentoseletrônicosnoquartocomtemposedentário, atividadefísicaeíndicedemassacorporaldecrianc¸as
Resumo
Objetivo: Descreveraassociac¸ãoentreequipamentoseletrônicosnoquartocomtempo seden-tárioeatividadefísica,ambosavaliadosporacelerometria,alémdoíndicedemassacorporal (IMC)emcrianc¸asdeSãoCaetanodoSul.
Métodos: A amostra foi composta por 441 crianc¸as. A presenc¸a de equipamentos eletrôni-cos (televisãoouTV,computador ejogos devídeo) noquarto foiavaliada pormeiode um questionário.Durantesetediasconsecutivos,ascrianc¸asusaramacelerômetroparamonitorar objetivamenteotemposedentárioeatividadefísicademoderadaavigorosa(AFMV).OIMCfoi categorizadoconformesugeridopelaOrganizac¸ãoMundialdeSaúde.
Resultados: Nototal,73,9%,54,2% e42,8% dascrianc¸astinhamTV,computadorejogosde vídeonoquarto,egastavamemmédia500,7e59,1min/diadetemposedentárioedeAFMV. Dascrianc¸as,45,3%tinhamexcessodepeso/obesidade.Meninascomcomputadornoquarto (45min/dia)faziammenosAFMVdoqueasquenãotinham(51,4min/dia).Resultados semel-hantesocorreramparaoIMCnosmeninos.AFMVfoimaioreIMCmenornascrianc¸asquenão tinhamequipamentoseletrônicosnoquarto.Computador(=-4,798)eacombinac¸ãodeTV comcomputador(=-3,233)foramnegativamenteassociadoscomAFMV.Jogosdevídeoeas combinac¸õescomdoisoutrêsequipamentoseletrônicosforampositivamenteassociadoscom IMC.Temposedentárionãofoiassociadocomequipamentoseletrônicos.
Conclusão: Equipamentoseletrônicosnoquartodascrianc¸aspodem afetarnegativamentea AFMVeoIMCindependentementedosexo,escolaerendafamiliaranual,podendocontribuir paraainatividadefísicaeobesidadeinfantil.
©2015SociedadeBrasileiradePediatria.PublicadoporElsevierEditoraLtda.Todososdireitos reservados.
Introduction
Sedentarybehavior,suchastheuseofelectronicequipment (TV,personalcomputer,andvideogames)in thechildren’s bedroom,ishighlyprevalentduringchildhood1andmaybe
associatedwithhealthrisks.2InBrazilandothercountries,
public health guidelines recommend that children should minimizetheamountoftimespentinprolongedsedentary behavior.3,4 The American Academy of Pediatrics
recom-mends that parents should remove electronic equipment fromchildren’srooms.5
Because 78.6% of Brazilian children watch >2h/dayof TV,6 the influence of electronic equipment in the
chil-dren’s lifestyle has been a key area of research7,8; for
instance, theimpactof thepresence of electronic equip-ment in their rooms.9 Studies carried out in developed
countries have found high levels of adiposity10,11 and
low levels of physical activity12 in children that
main-tainelectronicequipmentin thebedroom. Moreover,in a representative sample of English children participating in the study Sport, Physical Activity, and Eating Behaviour: Environmental Determinants in Young People (SPEEDY), Atkin et al.9 reported higher means of sedentary time
(objectively assessed) in children that had a TV and
computerinthebedroom,whencomparedtothosewhodid not.
Theobjectiveassessmentofphysical activitymeasured by an accelerometer provides detailed data representing physical activityintensities, such asmoderate-to-vigorous physicalactivity(MVPA),andeventhesedentarytime. Stud-ies using accelerometers have become more common in researchon childhoodphysical activity worldwide.8
How-ever, thenumber of studiesin developing countries,such as Brazil, which used accelerometers is still very small. Thus,the aim of this study is todescribe the association betweenthepresenceofelectronicdevicesinthebedroom withsedentarytimeandphysicalactivity,bothassessedby accelerometry,inadditiontobodymassindex(BMI)in chil-drenfromSãoCaetanodoSul,Brazil.
Material
and
methods
Samplestudy
conductedintwelvecountries.8ThedetailsofISCOLEhave
beenpreviouslypublished.8
Thepresent studyfocusesondatacollectedinthecity of São Caetano do Sul, in the state of Sao Paulo, Brazil, which hasan area of 15.3km2 anda subtropical climate. Thecity’s population in2013 consistedof 149,263 inhabi-tants,including1557children(812boysand745girls)aged 10years.13 Themaineconomicactivityofthecity consists
of theservice sector,13 andthe municipality has the best
HumanDevelopmentIndexofBrazil(0.86).14
Initially,contactwasmadewiththeDepartmentof Edu-cationandthentheinvitationtoparticipateintheproject wasmade.Aftertheapproval,theprojectwaspresentedat eachschoolaswellasthecouncilofparents;after obtain-ingtheauthorization,theprojectwasimplementedineach school.Allchildrenattendingthe5thgradeofElementary Schoolwereinvitedtoparticipate.
There is some variability in the socioeconomic status betweenschoolsinSãoCaetanodoSul.Publicschools rep-resentthelowestandlower-middlesocioeconomicclasses, while private schools represent the middle and upper-middle classes. Random lists of elementary schools were generated,consideringthenumberofschools(16publicand 4private),andtheywereselectedfromeachlistinafour (public)toone(private)ratio.Whenaschoolrefusedto par-ticipate,itwasreplacedbythefollowingschoolonthelist. Twentyschoolswereselected,inordertoobtainasample of25---30childrenfromeachschool.
Data collection was performed in the period between March 2012 and April 2013 and all measurements were conducted throughout an entire week per school. All data collection and management activities were car-ried out and monitored according to the quality control procedures implemented by the coordinating center of ISCOLE.8
Overall, 564 children (277 boys and 287 girls) were assessedand met thefollowing inclusion criteria: (a) age between9and11yearsold;(B)regularlyattendingaschool in São Caetano do Sul; and (c) no clinical or functional limitationsthat would preventthepracticeof daily phys-icalactivity.Aftertheexclusioncriteria(invaliddatafrom electronicequipmentandaccelerometry),thefinalsample consistedof 441children (216 boysand225 girls). Before participating in the study, the children’s parents and/or guardians signed an informed consent, according to Res-olution 196/96 of Conselho Nacional de Saúde do Brasil (NationalHealthCouncilofBrazil).Thestudyprotocolwas approvedbytheEthicsCommitteeoftheUniversidade Fed-eraldeSãoPaulo,Brazil.
Electronic
equipment
The presence and type (TV, computer, and videogames) of electronic equipment in the children’s bedroomswere reportedthroughtheNeighborhoodandHomeEnvironment Questionnaire.8 To adapt the questionnaire, three health
professionalswereinvitedtoparticipatein therespective phases. Detailed information on the questionnaire were sent and separate meetings were carried out with each professionaluntil a consensus wasreached regarding the questionnairecomposition,thequestions,theformsofthe
requested responses, and the result analysis procedures. Parentsand/orguardiansansweredthequestionsregarding thepresenceofTV,computer,andvideogamesinthe chil-dren’sbedrooms,andtheresponsetoeachitemwas‘‘yes’’ or‘‘no.’’
Accelerometry
The ActigraphGT3Xaccelerometer (ActiGraph®,USA)was usedtoobjectivelymonitorthesedentarytimeandMVPA. The accelerometer wasworn at thewaist attachedtoan elastic belt, in the mid-axillary line on the right side. Participants were encouraged to use the accelerometer 24h/day for at least seven days(plus another day of ini-tialfamiliarizationandduringthemorningofthelastday), including the two weekend days. The minimum amount of accelerometer data considered acceptable for analysis wasfour days(includingat least oneweekend day),with at least 10-h/day of use, after removal during sleeping time.15,16
Afterthelastdayofdatacollection,theresearchteam went to school to remove accelerometers. The research team verified whether the data were complete using the latest version of Actilife software (ActiGraph®, ver-sion 5.6, USA) available. Nine participants who did not providesufficientdataduringtheinitialmonitoringusedthe accelerometerinthesecondweektoensurethatthe mini-mumdatarequirementsweremet.Thedatawerecollected atasamplingrateof80Hz,downloadedatintervalsof1s, andthenaggregatedinperiodsof15s.17
This study used the calculation of counts for the accelerometercutoffpointsestablishedbyEvensonetal.17
forperiodsof15s.Specifically,fordatacalculation,the cut-offpointsof≤25counts/15sfor sedentarytimeand≥574 counts/15sforMVPAwereused.17Cutoffpointscapturethe
sporadicnatureofchildren’sactivitiesandprovidethebest accuracyofclassificationamongthecurrentlyavailable cut-offpointsforphysicalactivityinchildren.15
Body
composition
Thebodycompositionvariablesincludedinthestudywere height, body mass, and BMI. A battery of anthropomet-ricmeasurementswasperformedaccordingtostandardized procedures.8 Height was measured without shoes, using
a portable Seca 213 stadiometer (Seca®, Hamburg, Ger-many), withthe head in the Frankfurt plane. Body mass wasmeasuredusingaTanitaSC-240scale,aportablebody composition analyzer (Tanita®, USA), after the children removedheavyitemsfromthepockets,aswellasshoesand socks.2Twomeasurementswereobtained,andthemeanwas
usedintheanalysis(thethirdmeasurementwasobtainedif thefirsttwomeasurementshadadifferencegreater than 0.5kgor2.0%ofthebodyweight).
Electronicequipment,sedentarylifestyle,physicalactivity,andBMI 577
Covariates
A parent or legal guardian was asked to complete the NeighborhoodandHomeEnvironmentQuestionnaire,which includedquestionsrelatedtothechild’shealthhistoryand annualfamilyincome;thequestionswereaskedseparately totheparents.8Theannualfamilyincome(R$)wasusedas
ameasureofsocioeconomiclevelsandclassifiedintoeight categories that represent increasing levels of income, so thatthefamilieswithlowerincomewereclassifiedin the firstcategory,andthosewithhigherincomewereclassified in the highest category. Due to the variability in socio-economic status between public and private schools, the multivariateanalysiswasadjustedfortheschooltype.
Statistical
analysis
A descriptive analysis was calculated, including mean, standarddeviation(SD)frequencyandpercentage(%),and theKolmogorov---Smirnovtest wasusedtoassess data dis-tribution. Student’st-test wasperformed to compare the meansofcontinuousvariables(sedentarytime,MVPA,and BMI)withthepresenceorabsenceofeachelectronicdevice inthechildren’sbedrooms.19
Intheanalysis,thetotalnumberofelectronicdevicesin thechildren’sbedroomswasalsogroupedintonone, one, two,orthree.Thecomparisonbetweenthetotalnumberof electronicdevicesinthebedroom(none,one,two,orthree) withthemeans ofcontinuous variableswasperformedby analysisofvariance withonefactor,followed bythe Bon-ferronimultiplecomparisonsmethod.
The multiple linear regression analysis, using the ‘‘Enter’’method,wasperformed toassesstheassociation betweenelectronicequipmentinthebedroomwith seden-tarytime,MVPA,andBMI,adjustedforgender,school,and annualfamilyincome. TheStatisticalAnalysisSystem(SAS InstituteInc.,USA)wasusedfortheanalysis,andp<0.0519
wasconsideredsignificant.
Results
Ofthe441children,216(49%)wereboys,andmosthadaTV (326;73.9%)andacomputerinthebedroom(239;54.2%). Asforvideogames,189(42.8%)ofthechildrenhadthemin thebedroom.ThemeansedentarytimeandMVPAwas500.7 and59.1min/day,respectively(Table1).
MeanBMIwas19.8kg/m2.Basedonthecutoffpoints pro-posedbyWHO,1854.7%ofchildrenhadnormalweight,23.1%
wereoverweight,and22.2%wereobese(45.3%ofchildren wereoverweight/obese).
Regardingtheannualfamilyincome,mostofthefamilies hadincomelevelsofR$6540.00---19620.00(138;36.1%)or R$19620.01---32700.00(101;26.4%)peryear.
Table 2 shows thatthere wasno significant difference betweenthemeansofsedentarytimewiththepresenceor absenceof electronicequipment inthe bedroom, bothin theentiresampleandbygender.
ForthemeanMVPA,nosignificantdifferencewasfound regardingthe presence orabsence ofTVin the bedroom. Regardingthepresenceofacomputerinthebedroom,there
Table 1 Descriptivecharacteristics(mean[SD] orn [%])
of electronicequipment,sedentary time,MVPA, BMI, and children’sfamilyannualhouseholdincome.
Mean(SD)orn(%)
Gender(n=441)
Boys 216(49%)
Girls 225(51%)
TVinthebedroom(n=441) 326(73.9%) Computerinthebedroom(n=441) 239(54.2%) Videogamesinthebedroom(n=441) 189(42.8%)
Accelerometry(n=441)
Sedentarytime(min/day) 500.7(66.6)
MVPA(min/day) 59.1(25.7)
BMI(kg/m2;n=441) 19.8(4.5)
BMIcategories(WHOcutoff18;n=441)
Normalweight 241(54.7%)
Overweight 102(23.1%)
Obese 98(22.2%)
Annualfamilyincome(n=382)
<R$6540 8(2.1%)
R$6540.00---19620.00 138(36.1%)
R$19620.01---32700.00 101(26.4%)
R$32700.01---45780.00 49(12.8%)
R$45780.01---58860.00 32(8.4%)
R$58860.01---71940.00 24(6.3%)
R$71940.01---85020.00 16(4.2%)
>R$85020.01 14(3.7%)
MVPA, moderate-to-vigorous physical activity; min, minutes. BMI, body massindex; WHO, WorldHealth Organization; R$, Brazilianreal.
wasnosignificantdifferencebetweenthemeansofMVPAin theentiresampleorinboys.Regardingthegirls,thosethat didnothaveacomputerinthebedroomperformedamean of6.4min/dayofMVPAmorethanthosewithacomputerin thebedroom(p=0.009).Asforthepresenceorabsenceof videogamesinthebedroom,therewassignificantdifference betweenthemeansofMVPA(p<0.001).Thosewhodidnot havevideogamesinthebedroomperformed8min/daymore MVPAthanthosewhodid.
No significant difference was found in mean BMI with thepresence or absenceofTV inthe bedroom.Boys who hada computerin thebedroomhadonaverage 1.2kg/m2 greaterBMI than thosewhohad nocomputerin the bed-room(p=0.030).The meansofBMIshowednodifferences whetherthechildrenhadordidnothavevideogamesinthe bedroom(Table2).
Fig. 1 shows that there was no significant difference betweenthemeansofsedentarytimewiththenumberof electronicdevices in the children’sbedroom, both in the entiresampleandbygender.
Ferrari
GL
et
al.
Table2 Descriptiveanalysis(meanandSD)ofsedentarytime,MVPA,andBMIaccordingtothepresenceorabsenceofelectronicequipmentinthechildren’sbedroom.
TV Computer Videogames
Yes No pa Yes No pa Yes No pa
Sedentarytime (min/day)
Total 501.4(69.4) 497.9(63.8) 0.616 504.6(72.2) 495.0(62.0) 0.130 500.6(66.8) 501.3(66.8) 0.905 Boys 491.7(72.6) 493.4(64.3) 0.870 494.1(73.5) 488.4(65.8) 0.545 494.8(69.3) 491.2(66.2) 0.707 Girls 510.7(65.0) 502.2(63.5) 0.381 515.3(69.6) 501.0(58.0) 0.094 513.9(59.1) 506.5(66.7) 0.429
MVPA(min/day)
Total 58.4(26.4) 61.1(23.8) 0.294 57.3(25.8) 61.2(25.7) 0.117 55.4(27.2) 64.1(24.0) <0.001b
Boys 70.4(28.3) 71.0(24.6) 0.878 69.6(26.1) 72.0(29.0) 0.512 68.1(26.6) 72.2(28.5) 0.283
Girls 46.8(18.0) 51.6(18.7) 0.091 45.0(18.8) 51.4(17.2) 0.009b 49.0(17.9) 45.4(18.4) 0.188
BMI(kg/m2)
Total 19.9(4.5) 19.2(4.0) 0.102 20.1(4.8) 19.3(3.9) 0.054 20.1(4.9) 19.4(3.9) 0.100
Boys 20.0(4.9) 19.2(4.0) 0.185 20.4(5.4) 19.2(3.5) 0.030b 20.0(5.0) 19.4(3.8) 0.325
Girls 19.8(4.2) 19.2(4.1) 0.327 19.7(4.2) 19.5(4.3) 0.609 20.3(4.7) 19.4(4.0) 0.178
TV,television;MVPA,moderate-to-vigorousphysicalactivity;BMI,bodymassindex. a Student’st-test,p<0.05.
Electronicequipment,sedentarylifestyle,physicalactivity,andBMI 579 800 700 600 500 400 0 100 80 60 40 20 0 30 25 20 15 0 506.8 506.1 490.6
480.1496.5 503.1492.7 516.2 507.6 71.1 61.8 52.4 61.3 72.5 50.1 55.6 65.9 45.2 * * * * * *
19.2 19.3 19.1 19.5 19.3 19.5
21.1 20.721.6
Boys Girls Total
Number of electronic devices in the bedroom
None One Two or three
Number of electronic devices in the bedroom
None One Two or three
Number of electronic devices in the bedroom
None One Two or three
Sedentary time (min/day)
MVP
A
(min/day)
BMI (kg/m
2)
A
B
C
Figure 1 Mean sedentary time (A), MVPA (B), and BMI (C)
according tothe number of electronicequipment devices in thechildren’s bedroom. Analysisofvariance with onefactor followedbyBonferronimethod(p<0.05).MVPA, moderate-to-vigorousphysical activity; BMI, body massindex.*Difference betweennoneandtwoorthreeelectronicequipmentdevices. n=77 (no electronic equipment); n=111 (one electronic devices);n=253(twoorthreeelectronicdevices).
ForBMI,asignificantdifferencewasfoundbetweenthe meansaccordingtothenumberofelectronicdevicesinthe bedroom.Childrenwhohadnoelectronicdevicesinthe bed-roomhadlowermeanBMIthanthosewhohadtwoorthree electronicdevicesinthebedroom.
For the entire sample, Table 3 shows the results of the multivariate regression analysis, adjusted for gender, school,and annualfamilyincome, describing the associa-tionbetweenthepresenceofelectronicequipmentin the bedroom withsedentary time,MVPA, and BMI.There was no significant association between any of the electronic
equipmentunits,evenwhencombinedinthemultivariate analysiswithsedentarytime.
The presence of a computer in the bedroom and the combination of TV and computer were negatively associ-atedwithMVPA.Forallotheritemsofelectronicequipment, therewasnosignificantassociationwithMVPA(Table3).
A significant positive association was found for videogamesandthecombinationoftwoorthreeelectronic devicesinthebedroomwiththechildren’sBMI(Table3).
Discussion
The aim of this study was to describe the associa-tion between electronic equipment in the bedroom with sedentary time and physical activity, both assessed by accelerometry, in additionto BMI in children of São Cae-tanodoSul.The resultsdemonstratedthatchildrenspend 500.7min/dayofsedentarytimeand59.1min/dayofMVPA, and45.3% had overweight/obesity. The presence of elec-tronicequipmentinthebedroomwasnegativelyassociated withMVPA. In addition, the presence of videogames and combinationswith twoor threeelectronic devices in the bedroomwerepositivelyassociatedwithchildren’sBMI.
This study confirms previous studies, which showed a negative association between electronic equipment in the children’s bedroom with MVPA, evaluated by an accelerometer.20,21Forinstance,inastudywithchildrenin
theUnitedStates,O’Connoretal.,21 usingadifferent
cut-offpoint(≥2296counts/min)fromthatusedinthepresent study(≥574counts/15s)toclassifyMVPA,foundanegative association(ˇ=−2.33)betweenthepresenceofelectronic equipment(TV,computer,videogames,andDVDplayer)in thechildren’sbedroomwithMVPA.
Thepresentstudyfoundanegativeassociationbetween the presence of the computer (ˇ=−4.798) and the com-binationofTVandcomputer(ˇ=−3.233)inthechildren’s bedroomwithMVPA.Becausesomeotherstudies9,11didnot
findasignificantassociationbetweenelectronicequipment inthebedroomwithMVPA,conflictingresearchresultsmust occur due to individual behavioral differences, including childrenwith‘‘lesshealthy’’behaviorsandhealthier behav-iors,inordertomaintaintheenergybalanceofthebodyand bodymass.11
Althoughthepresent studydidnotshowan association betweenthepresenceofelectronicequipmentinthe bed-roomwithsedentarytime,studies in developedcountries such as Canada11 and the United Kingdom9 showed
simi-lar results to this study. In a study that was part of the SPEEDY trial, Atkin et al.9 found that the presence of
electronic equipmentin the bedroom was not associated withsedentary time (defined as <100 counts/min). Some researchers22,23 suggest thatTVviewing,for instance,can
bea generalindicatorofsedentary lifestyleandmightbe onlyanindicatorofthetotaltimeofsedentarybehavior.24,25
Thepresentresultsareinagreementwithprevious stud-ies showing that the presence of at least two electronic equipmentunitsinthechildren’sbedroomisassociatedwith increasedrisk of excess weight.11,26 For example,
Ferrari
GL
et
al.
Table3 Adjustedanalysisbetweenelectronicequipmentinthebedroomandsedentarytime,MVPA,andBMIofchildren.
Electronicequipment inthebedroom
Sedentarytime MVPA BMI(kg/m2)
ˇcoefficient 95%CI pa ˇcoefficient 95%CI pa ˇcoefficient 95%CI pa
TV 5.289 −10.248,20.825 0.504 −3.240 −8.634,2.155 0.238 0.838 −0.138,1.815 0.092
Computer 8.157 −5.394,21.708 0.237 −4.798 −9.508,−0.088 0.046b 0.804 −0.058,1.666 0.068
Videogames 5.920 −8.357,20.196 0.415 −0.008 −5.081,5.065 0.997 0.943 0.038,1.849 0.041b
TV+PC 4.100 −4.768,12.967 0.364 −3.233 −6.337,−0.128 0.041b 0.661 0.097,1.224 0.022b
TV+VG 4.094 −4.816,13.005 0.367 −1.377 −4.510,1.757 0.388 0.625 0.073,1.178 0.027b
PC+VG 5.340 −3.228,13.908 0.221 −2.135 −5.146,0.876 0.164 0.656 0.117,1.194 0.017b
TV+PC+VG 3.620 −2.785,10.024 0.267 −1.796 −4.044,0.452 0.117 0.521 0.118,0.925 0.011b
MVPA,moderate-to-vigorousphysicalactivity;BMI,bodymassindex;95%CI,95%confidenceinterval;TV,television;PC,personalcomputer;VG,videogames. a Linearregressionadjustedforgender,schoolandannualfamilyincome.
Electronicequipment,sedentarylifestyle,physicalactivity,andBMI 581
estimate excess weight. The authors analyzed the same electronicdevicesassessedinthisstudyandfounda nega-tiveassociationwithbodyfatpercentage.Childrenwithtwo orthreeelectronicdevicesinthebedroomhadhighermean valuesofbodyfatthanthosewhodidnothave electronic devicesinthebedroom(24.5%versus20%).
As accelerometry requires a combination of financial resources and technologicalknowledge, it haschallenged researchers from developing countries. In several previ-ous studies, Brazilian researchers based their studies on questionnairestoquantifythesedentarytimeandphysical activity,concentratingonlyontheamountoftimespentin frontofelectronicdevices,especiallyTV.27---29Thisisthefirst
Brazilianstudytosuggestthatthepresenceofoneormore electronicdevicesinthebedroomisassociatedwithMVPA andBMI.
The authors believe that the strengths of this study includetheobjectivemeasuresofsedentarytimeandMVPA, astheirrespectivetechniques andapproaches arerarein Brazil, considering that the majority of previous studies usedquestionnairesandindirectmeasurestoassessphysical activity.29,30Thisstudyincreasestheknowledgeofthe
exist-ingliteratureontheassociationbetweensedentarytimeand MVPA,assessedbyaccelerometrywiththepresenceof elec-tronicequipmentinthechildren’sbedroom.Althoughit pro-videsaccelerometrydata,ithassomelimitations:the cross-sectionaldesign preventsthe establishmentof cause-and-effectassociationsandthelackofrepresentativenessofthe samplepreventsdataextrapolationtoBrazilianchildren.
Thisstudyprovidesevidenceofassociationsbetweenthe presenceofelectronicequipmentinthebedroomwithMVPA and BMI, regardless of gender, school, and annual family income.Particularly,twoorthreeelectronicdevicesinthe bedroom are associated with low MVPA and high BMI. No significantassociationbetweenelectronicequipmentinthe bedroomandsedentarytimewasfound.
Funding
The ISCOLE Brazil research project was funded by the Coca-Cola Company. The funder had norole in the study design,datacollectionandanalysis,decisiontopublish,or manuscriptpreparation.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
Acknowledgements
The authors wouldlike tothankthe participants,parents and/or guardians,teachers,and coordinatorsof Municipal SecretariatofEducationofSãoCaetanodoSulandtheTown HallofSãoCaetanodoSul.
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