index (r=-0.36;p UIC per school were negatively correlated with stunting prevalence (r = -0.39;p of requirements of iodine intake wasof requirementsiodineintake found(medianUIC297μg/L).Iodinestatuswas foundasde ensino fundamentalde10 municípiosdoestadodeQuerétaro,noMéxico. indicadores denutriçãogeralecomoíndicedesigualdadesocial (IDS)de50escolasestaduais em 2,4,19 Setenta e25escolas,respectivamente. eseteporcentodeamostrassalmesamos deiododeterminado foideficiente,adequado,maisdoqueadequadoeexcessivo 297 μg/L).Onível total de1.544 criançaseencontrou-seumaingestãoacimadasnecessidadesdeiodo(CIU medianade consumo dealimentosourefeições ricos(as)emenergiaesaliodado. de pesoeaobesidadenãofoidescrita anteriormenteepoderiaserexplicadapeladisponibilidade e Em nosso conhecimento,a correlação entreaCIU,de iodo(insuficienteeexcessiva). positiva oexcesso Arq Bras Metab. Endocrinol 2013;57/6 vamente comaCIU(p modelos deregressãomúltiplamostraram queaDPdoIMCealturaforamrelacionadossignificati desnutrição (r=-0.39;p < 0,05). As medianas deCUIporescolaforamcorrelacionadas negativamentecomaprevalência de p as medianasdoíndicedemassacorporal(IMC)usandoodesvio-padrão dacontagem(DP)(r=0,47; de iodo baixo (<15 ppm). As medianasdeCIU por escolaforamcorrelacionadas com positivamente traram umaquantidadede iodo adequada(20-40ppm),enquanto9,6%das amostras tinhamumteor Objetivo emétodos: RESUMO bility andconsumptionofsnack foodrich inenergyandiodized salt. nificantly relatedwithUIC(p height SDS(r=0.41;p medians ofbodymassindex(BMI)byusingthestandarddeviationscore(SDS)(r=0.47;p samples hadlowiodinecontent(<15 ppm).MediansofUICperschool correlated werepositively with seven percentoftablesaltsamplesshowedadequateiodinecontent(20-40ppm),while9.6%the in2,4, ficient, adequate,morethanadequateandexcessive 19 and25schools, respectively. Seventy Objective andmethods: ABSTRACT Pablo García-Solís estado nutricional geral eoíndicede desigualdadesocial México: correlação entre aconcentração deiodo, urinária o Consumo deiodoemescolasensinofundamental deQuerétaro, status andsocialgapindex concentration withglobalnutrition correlations between iodine urinary schools ofQueretaro, Mexico: Iodine nutrition inelementary state Villarreal-Ríos Nutrição comiodo;obesidade; concentraçãourináriadeiodo;crianças emidadeescolar;desnutrição;índice dedesigualdadesocial Descritores Gaytán Iodine nutrition; obesity; urinary iodineconcentration;schoolchildren;stunting;socialgapindex Iodine nutrition;obesity;urinary Keywords municipalities intheStateofQueretaro,Mexico. andsocialgapwith globalnutritionindicators index(SGI)in50elementarystateschools from10 UIC andoverweight andobesityhasnotbeendescribedbefore,couldbeexplainedbythe availa (insufficientiodine intake andexcessive). correlationTo ourknowledge,theobservedpositive between < 0.005), oDPdaaltura(r=0,41;p <0.005), 1 , VanessaA. Reyes-Mendoza <0.05).BestmultipleregressionmodelsshowedthatBMISDSandheightweresig 2 , LuisaLeal-García Estimar a concentração de iodo urinário (CIU) mediana e correlacioná-la com os Estimar aconcentraçãodeiodourinário(CIU)medianaecorrelacioná-la comos <0,05). <0.05),andoverweight andobesityprevalence(r=0.41;p = 005) ecomoíndicededesigualdadesocial(r=-0.36;p =005) 1 , Juan Solís-S Carlos To estimatemedianurinaryiodineconcentration(UIC),andtocorrelate it <0.05). Conclusão: <0.05)eaprevalênciadesobrepesoobesidade(r=0,41;p Conclusions: 3 Existe uma convivência entre os dois extremos de ingestão Existe umaconvivênciaentreosdois extremosdeingestão , LuisHernández-Montiel Hebert 1 , LudivinaRobles-Osorio Results: 1 There is coexistence between the two extremes of There iscoexistencebetweenthetwoextremesof , García-Ana Cristina 1,544 students were enrolled and an above 1,544 studentswereenrolledandanabove Arq Bras Endocrinol Metab. 2013;57(6):473-82 Arq BrasEndocrinolMetab. 2013;57(6):473-82 Resultados: 1 , Enrique = 005) and social gap andsocial gap =005) < 0,05). Os melhores <0,05).Osmelhores < 0.05). Medians of <0.05).Mediansof 1 Utilizou-se um Utilizou-se um < 0.005), <0.005), - - - - - de Querétaro, Méxicode Querétaro, Universidad AutónomaMedicina, de Biomédica, Facultad Autónoma México deQuerétaro, Administración, Universidad MéxicoSeguro Social,Querétaro, de Salud,Instituto Mexicano del Epidemiológica yenServicios 1 Accepted onJuly/11/2013 Receivedon Apr/11/2013 [email protected] C.P. 76176. México Querétaro. de laCapilla,Querétaro, Clavel,Querétaro Fracc. 200. Prados Medicina, Universidad Autónoma de Investigación Biomédica,Facultad de de y Nutrición,Departamento Laboratorio deEndocrinología Pablo García-Solís Correspondence to: 3 2 Departamento deInvestigaciónDepartamento Facultad de Contaduría y Facultad deContaduría Unidad deInvestigación original article original 473

Copyright© ABE&M todos os direitos reservados. Copyright© ABE&M todos os direitos reservados. 474 in2006it was16.6%(3,9).Thisnu 19.5%, whereas was significantly; in1999,anemiaprevalence improved havenot deficiencies, suchasanemia inschoolchildren in 2006 it was 9.9% (3,9). However, other nutritional in 1999 was 16.1%, whereas valence in schoolchildren stuntingpre in thelastyears.Inthisregard, improved hasbeennotably undernutrition ofchronic the control ght andobesityof26.2%(3,9).Ontheotherhand, ofoverwei aprevalence reported trition Survey-2006 18.4%; sevenyearslater, theNationalHealthandNu (5to11yearsofage) and obesityinschoolchildren of overweight a prevalence The NNS-1999 reported of infectiousdiseasesandnutritionaldeficiencies(8). andobesityareduction ofoverweight problems withserious anutritiontransitioncountry considered iodized saltispoorlyunderstood.Moreover, Mexicois of households ofMexico,andtheconsumption pattern aboutiodinecontentintablesalt national surveys norecent are tee adequateiodinecontent(7).There thatdonotguaran producers artisanal local andfrom oftablesaltare thesources salt (7).Intheseregions, iodinecontentintable withstillinsufficient regions than15ppmofiodine(6);however,more are there mated that94%tablesaltavailableinthemarkethas in Mexico, it is esti to the USI program According (3-5). median UIC of235and176μg/L, respectively a (with23sentinelsites),reported mobile program andtheThyro survey) (NNS-1999) (aprobabilistic tween 1998and1999,theNationalNutritionSurvey be performed iodinenutrition were studies regarding national sample(2).InMexico,thelasttwo yearsinarepresentative three mended atleastevery dine deficiency,recom and themonitoring ofUICis indicatesio UIC below100μg/Linschoolchildren andlactatingwomen(2).Amedian value of pregnant andboth vulnerable population,suchasschoolchildren iodineconcentration(UIC)in assessment ofurinary monitoring of iodine intake bymeansofthe permanent andthe universalsaltiodization(USI)program tory toestablishamanda to eradicateiodinedeficiencyare ventable braindamage(2).Two ofthemainstrategies (ICCIDD), iodinedeficiencyis themain causeof pre of Iodine Deficiency Disorders nal Council for Control I INTRODUCTION Iodine nutrition inMexican schoolchildren Nations Children Fund(Unicef),andtheInternatio Nations Children to theWorld HealthOrganization (WHO),theUnited nutritional deficiencies worldwide (1). According nutritional deficienciesworldwide(1).According odine deficiencyisstilloneofthemostimportant ------(10), approximately 270 km to the northwest of Me 270 km to the northwest (10), approximately (20°40’-20º1’N,99°2’-100º36’W) the country islocatedatthecenter of man. ThestateofQueretaro Escobedo,PinaldeAmoles,SanJoaquin, andTolidro Pe , , , Amealco,Colon,ElMarques, nicipalities studiedwere Mexico.The mu the state ofQueretaro, palities from in10munici studywasperformed This cross-sectional Setting andsubjects SUBJECTS ANDMETHODS tus andthesocialgapindex,asocioeconomicindicator. withtheglobalnutritionsta ciency anditsrelationship vulnerabletoiodinedefi in municipalitiesconsidered stateschools elementary from tus inMexicanchildren study,cross-sectional we describe iodine nutrition sta situationofiodinenutritioninMexico.Inthis current to describe the tritional contextmakes it mandatory based on this criterion were Amealco, PinaldeAmo based on thiscriterionwere (9). The municipalities selected national prevalence thanthecurrent >10%,whichismore as aprevalence a second criterion. Highstuntingratewasconsidered used as were (18,19), highratesofstunting prevalence undernutrition andchronic associated withpoverty (17). Ontheotherhand,becauseiodinedeficiencyis commoninmountainousareas Iodine-deficient soilsare mountainrange. Oriental,animportant Madre Sierra de Amoles,SanJoaquin,andToliman ofthe part are Pinal LandadeMatamoros, acteristics. JalpandeSerra, and SanJoaquinisassociatedwithgeographicalchar goiter inthesemunicipalities,andPinaldeAmoles andTolimanLanda deMatamoros, (15,16).Endemic JalpandeSerra, ties selectedbasedonthiscriterionwere the criteriadescribedbelow. to vulnerabletoiodinedeficiencyaccording more red state,weselected10municipalitiesconside Queretaro onUICinthe information cause ofthelackrecent range ofaltitude(14)eachmunicipalitystudied.Be of stunting (13), and gap index(SGI) (12), prevalence (12),social poverty population(11),extreme children characteristics, suchastotalpopulation(10),school Table 1showsmajorgeographicandsociodemographic senting 24.2%ofthetotalpopulationstate(10). total populationofthe10municipalitiesstudiedrepre has1,827,937inhabitants,with the state ofQueretaro xico City. tothe2010 national census,the According Historic records ofendemicgoiter:themunicipali Historic records Arq Bras Metab. Endocrinol 2013;57/6 ------Arq Bras Metab. Endocrinol 2013;57/6 Reference: 10*, 11**, 12***, 13 Table 1. Socio-demographicandgeographiccharacteristicsofthestudiedmunicipalities voluntarilytook Allparticipants versity ofQueretaro. tee oftheSchoolMedicineAutonomousUni May2010toJuly2011. collectedfrom were andall data eachschoolwas23to36children, from older than12yearsold.Therangeofsubjectssampled younger than 6 years old, and only 2.5% were ied were stud day ofthedatacollection.Only1.2%children availableonthe we decidedtoincludeallthechildren totheselocations, return to Because ofthedifficulties in somecases,agerangewasbetween5to16yearsold. in the day of data collection was less than 30, and part However, thattook in7cases,thenumberofchildren enoughtocalculatethemedianofUIC(2). ples are the study. Ingeneral,itisacceptedthat30urinesam in ofbothgendersto participate select 30-35children eachschoolwasasked torandomly The Principalfrom includedinthisstudy(11). to 12yearsofagewere between6 than30children Only schoolswithmore site. schoolwasselectedasthesurvey state elementary eachmunicipality.(14), 5from eachlocality, From one and24%urban) randomly selectedlocalities(76%rural Escobedo(22,23). and Pedro Huimilpan, Colon, El Marques, on this criterion were 2007,andthemunicipalitiesselectedbased data from (20,21).Forthisselectionweused tional prevalence thantheaverageofna whichismore live births; asarate>4.2/10,000 wasconsidered hypothyroidism criterionofselection.Highratecongenital a third usedas were high ratesofcongenitalhypothyroidism les, SanJoaquin,andToliman (Table 1)(13).Finally, Toliman San Joaquin Landa deMatamoros Jalpan deSerra Huimilpan El Marques Colon Pinal de Amoles Pinal Amealco Municipality This study was approved bytheBioethicalCommit This studywasapproved We 50 from studiediodinenutritioninchildren Total population* + , 14 ++ 116,458 26,372 63,966 19,929 25,550 35,554 58,171 27,093 62,197 8,865 . Schoolchildren population** 15,580 10,216 3,932 1,365 8,873 3,464 3,983 5,738 8,904 5,278 poverty***, % Extreme - - - - - 17.3 25.3 24.2 18.2 12.4 11.4 34.9 25.4 8.8 7.2 from at least one parent or guardian. orguardian. atleastoneparent from inthestudyandwrittenconsentwasobtained part assessment of the analytical procedure ofUICwas car assessment oftheanalyticalprocedure qualitycontrol perliter(µg/L).External micrograms 6% and8%,respectively. in MedianUICwasexpressed ofvariationwere (24). Intra-andinterassaycoefficients toPinoandcols. with ammoniumpersulfate,according method aftersampledigestion by theSandell-Kolthoff performed were analysis.UICdeterminations further the laboratory, at -20°C until stored they were where to ethylene tubesandkeptat4-10°Cuntilarriving placed inpoly urine samplecontainers.Sampleswere in40-mLsterileplastic schoolchildren tained from the sodiumthiosulfatetitrationmethod(2). using performed titative iodineanalysesoftablesaltwere iodine concentration.Quan to quantitativelydetermine each municipality was randomly selected 24.6%), from tive subsampleoftablesaltsamples(between10.9and (Bioteccsa Laboratorios,Sonora,Mexico).Arepresenta ofiodateusingakit qualitatively toidentifythepresence analyzed their homes.Alltablesaltsampleswere salt from We tobringasampleof≈40gtable askedthechildren Laborator Resource LaboratoriesforIodineNetwork. Resource fortheInternational Laboratory Regional Resource andisamemberof the andPrevention, ease Control oftheCentersfor Dis Quality ofIodineProcedures isincludedintheEnsuring ofMicrutrients ratory University. Peruvian the CayetanoHeredia TheLabo (LM)of ofMicronutrients ried outbytheLaboratory On the other hand, spot urine samples were ob On theotherhand,spoturinesampleswere Social gapindex -0.72830 -0.00523 -0.45104 -0.23528 -0.22066 -0.72304 0.30120 0.34660 0.68236 0.52864 *** y anal y sis Iodine nutrition inMexican schoolchildren Schoolchildren prevalence stunting 12.5 15.6 19.7 14.7 12.1 9.6 7.5 7.9 9.7 5.5 + , % Altitude range 1,468 -1,937 1,597 -2,450 1,661 -2,337 2,356 -2,770 1,933 -2,431 1,859 -2,206 1,751 -2,573 1,033 -1,612 1,915 -2,200 756 -1,503 ++ , m 475 ------

Copyright© ABE&M todos os direitos reservados. Copyright© ABE&M todos os direitos reservados. 476 of theCONEVAL (12). homepage apublic databaseattheinternet ned from and foodaccess.SGIdatafor eachlocalitywasobtai because itdoesnotconsider income,socialsecurity, lity andlocality. measurement SGIisnotapoverty levels:state,municipa different atthree information theNationalCensus2010,andprovidetained from used byCONEVAL ob tocalculatetheSGIwere SGI valuesindicatepoorsocialdevelopment.Data lity andspaceshomeassets(4indicators).High (3indicators),andd)housingqua to basicservices (1indicator),c)accesstors), b)accesstohealthcare gorized infourdimensions:a)education(3indica ponent analysisthatsummarizes11indicatorscate obtainedbymeansofaprincipalcom measurement (12).TheSGIisa ofpoverty tion, andmeasurement guidelines andcriteriaforthedefinition,identifica to establishtheseauthority andhastheresponsibility totheMexicanlaw,that, according the represents luation ofSocialDevelopmentPolicy(CONEVAL) bytheNationalCouncilforEva SGI wascreated Social gapindex (SGI) (27,28). WHO standard totheheight-for-agewas definedas≤-2SD,according BMI-for-age WHO 2007 criteria (27). A stunted child byusingthe determined were and obesityprevalence toCacciariandcols.(26).Overweight lated according calcu (SDS).SDSwere deviationstandards as standard expressed height and BMI were homogeneity reasons, mass index(BMI)wasestimatedforeachsubject.For centimeter. 100gandheighttothenearest rest Body light indoorclothing.Weight tothenea­ wasrecorded theirpocketsemptied,andtheywore removed, were shoesof the subjects measurements, anthropometric (25). For the procedures anthropometric by standard determined were The weightandheightofthechildren status indicators Anthropometric measurementsandglobalnutrition ≥ 300µg/L. 200-299 µg/L;andexcessiveintakeofiodineasUIC asUIC µg/L; iodineintakeabovetherequirements µg/L; adequateintakeofiodineasUIC100-199 take wasdefinedasapopulationmedianUIC<100 iodinein ICCIDD criteria(2),asfollows:insufficient WHO/Unicef/ totherecommended mined according Iodine nutrition inMexican schoolchildren The iodine nutrition status in children wasdeter The iodinenutritionstatusinchildren ------We geo-politicalle tothree dataaccording grouped with medians of BMI SDS and height SDS and SGI. medianUIC torelate performed tests were correlation Because medianshadaGaussiandistribution,Pearson distribution. se thesevariablesdidnotshowanormal obesityandstunting becau ofoverweight, prevalence medianUICwiththe tocorrelate performed were tests correlation of UIC. Spearman groups unpaired and Kruskal-Wallis usedforcomparisonsof testswere U test.Non-parametric Mann-Withney bus normality distributed weusedD’AngostinoandPersonomni tributed. To analyzeifdatashowGaussian(normal) dis notnormally ght SDSdataofeachchildthatare and rangesincasesofindividualUIC,BMISDS,hei deviation,orasmedians means±standard shown are thestatisticalanalyses. La Jolla,CA)toperform Inc. IL), andGraphPadPrism5(GraphPadSofware, tion, Redmond,WA), SPSS16.0(SPSSInc.Chicago, We Corpora Excel2007(Microsoft usedMicrosoft Statistical analysis age oftablesalt samplesnegativetoiodate wasPinal the municipality with the highest percent vertheless, (Tablesamples showingnegativeiodate results 3).Ne­ withonly5%ofthe the studiedchildren, lected from Escobedo(36%). found inPedro andobesitywas ence ofoverweight the highestpreval of stunting was found in Pinal de Amoles (12.3%), and andobesity.ting, overweight, The highestprevalence lowest BMI.Table ofstun 2alsoshowstheprevalence hadthe the lowestheight.Inaddition,JalpandeSerra and Pinal de Amoles had cipalities of Jalpan de Serra themuni SDS andBMISDS.Asitmaybeobserved, 9.3 ±2.1yearsofage.Table 2showsthemedianheight cluded, withamale/femaleratioof1.07,andmean in Mexico,were nicipalities) ofthestateQueretaro, In thisstudy, 50localities(10mu from 1,544children RESULTS statisticallysignificant. considered < 0.05were (Model 1 and Model 2).P values reported analysis are The bestmodelsobtainedduringtheexploration ght SDSandSGIasindependentvariables(Table 5). altitude, iodinecontentintablesalt,BMISDSorhei each school as a dependent variable, andof UIC from usingthe median performed analyseswere regression vels: locality, municipality, andstate.Multiplelinear Nine hundred sixteen samples of table salt were col sixteensamplesoftablesaltwere Nine hundred Arq Bras Metab. Endocrinol 2013;57/6 Values ------Table 3. Qualitativeandquantitativeanalysisofiodinecontentintablesaltsamples bymunicipality * Mean±standarddeviation. BMI: bodymassindex;F: female;M: male. SDS: standarddeviationscore. Table 2. Generalcharacteristicsofthelocationsandscholarsbymunicipality median valueandmultiplecomparisontests(Kruskal-Wallis andDunn’s tests). 95%CI: 95%Confidenceinterval. Arq Bras Metab. Endocrinol 2013;57/6 intheUICcom andfoundnodifferences years group range (5to16years)weanalyzedseparatelythe6-12 sites.Duetothewideage obtained inthe50survey pality, ofUICmedianvalues includingthe frequencies respectively. Colon andPinaldeAmoleswith26.320%, were iodinecontent(<15ppm) salt sampleswithinsufficient of table percentage The municipalities with thegreatest and salt sampleshadiodinecontentbetween20-40ppm, sample oftablesalt(Table 3).Atotalof77.8%table the quantitativeanalysisofiodinecontentinsub with inagreement de Amoles(14.7%).Thesedataare Amealco Municipality All Toliman San Joaquin de Amoles Pinal Pedro Escobedo Landa deMatamoros Jalpan deSerra Huimilpan El Marques Colon Amealco Colon El Marques Huimilpan Jalpan deSerra Landa deMatamoros Pedro Escobedo Pinal de Amoles Pinal San Joaquin Toliman All Table foreachmunici 4showsdetailedUICresults Municipality 9.6% ofthesampleshadiodinecontent<15ppm. 1,544 150 149 153 154 161 156 150 153 164 154 117 128 109 916 Qualitative analysis 81 79 86 89 61 79 87 n n Age (years)* negative, % 9.4 ±2.1 9.3 ±2.1 9.1 ±1.9 9.6 ±2.0 9.2 ±2.2 9.4 ±1.9 9.5 ±2.1 9.5 ±2.1 8.9 ±2.2 9.3 ±2.0 9.2 ±2.0 Iodate 14.7 3.4 4.9 2.5 0.0 9.0 2.3 8.2 0.0 9.2 5.1 Height SDS (median) -0.261 -0.254 -0.442 -0.412 -0.256 -0.300 -0.632 -0.606 -0.228 -0.193 -0.360 167 18 19 18 18 14 14 18 15 15 18 n a,b a,b a,b a,b a,b a,b b b a a 23.8 ±12.3 30.8 ±11.4 28.0 ±11.1 26.2 ±11.2 29.0 ±10.6 Mean ±SD 32.9 ±6.0 25.1 ±5.8 31.2 ±5.0 26.5 ±8.3 30.4 ±7.5 28.4 ±9.4 (median) BMI SDS 0.099 -0.005 0.532 0.326 0.485 0.249 0.323 0.038 -0.268 - - - 0.508 0.248 a,b,c a,b a,b a,b a,b a,b b,c b,c a c vidual analysis. apopulationanalysisinsteadofindi school toperform each dine intake,weusedUICmedianvalues from notusefulto estimate individualio urine samplesare spot other hand,becauseUICvaluesobtainedfrom andtheotherinPinaldeAmoles.On Matamoros ficient iodineintake(50-100μg/L),oneinLandade the 50 studied, with insuf found twolocalities,from in 4municipalities(≥300μg/L).Inspiteofthis,we μg/L) in6municipalities,andexcessiveiodineintake than adequateiodineintake(medianUICof200-299 225 μg/Lto531μg/L.Thesevaluesindicatemore above200µg/L,andrangewasfrom medians were withthe whole sample.Inall municipalities, UIC pared a, b, c b, a, Differentlettersindicatestatisticallysignificantdifferences(p<0.05), accordingto Iodine concentration, ppm Median 12.3 10.0 6.1 4.7 8.5 1.9 7.7 7.2 1.8 1.9 5.3 33 24 25 30 34 29 24 27 25 30 29 Quantitative analysis % Stunting 7.1-17.5 5.2-14.8 4.1-12.9 3.5-11.9 3.1-11.3 -0.2-4.0 -0.2-3.8 -0.3-4.1 95% CI 4.9-7.3 1.3-8.1 1.7-8.9 <15, % 26.3 14.3 11.1 20.0 13.3 0.0 5.6 0.0 7.1 0.0 9.6 Iodine nutrition inMexican schoolchildren ≥ 20-40, % Overweight andobesity 24.7 11.7 17.3 31.5 20.9 36.0 15.7 20.3 34.7 26.0 21.3 100.0 83.3 63.2 83.3 64.3 71.4 72.2 73.3 80.0 83.3 77.8 % 22.5-26.9 11.3-23.5 24.0-39.0 14.5-27.3 28.6-43.4 10.0-21.4 13.9-26.7 27.4-42.0 19.1-32.9 14.8-27.9 6.6-16.8 95% CI > 40, % 16.7 21.4 16.7 5.2 0.0 0.0 0.0 6.7 6.7 5.6 7.8 477 - - -

Copyright© ABE&M todos os direitos reservados. Copyright© ABE&M todos os direitos reservados. 478 d c, b, a, Table 4. iodineconcentrationsbymunicipalityandschool Urinary effect ofaltitude. find anysignificant other dependent variables, wedidnot When weexplored withUIC. significantlycorrelated = 99.94<0.05)were cases BMISDS(β was includedasadependentvariableinModel2.Inboth (Model 1).Similarly, aninsteadofBMISDS,heightSDS content intablesalt,andBMISDSasdependentvariables with UICastheindependentvariableandSGI,iodine was negative(Pearsonr=-0.36;p between UIC with SGI coefficient hand, the correlation ( valuesofr=0.37(p Spearman yielded andobesityprevalence prevalence overweight p r = 0.41; (Spearman and obesity prevalence overweight betweenUIC and coefficient significant correlation 2Dshowsapositiveand = 0.003).Incontrast,figure r= -0.39; p (Spearman UIC and stuntingprevalence between coefficient negative andsignificant correlation 0.001) ineachlocality. 2Cshowsa Figure Furthermore, 0.002), andthemedianBMISDS(Pearsonr=0.47;p UIC andthemedianHeightSDS(Pearsonr=0.41;p betweenthemedian positive andsignificantcorrelation 2AandBshowa 2and3.Figures showninFigures are the50schools status indicatorsandSGIusingdatafrom analysesbetweenUICandglobalnutrition Correlation tion ofUICmedianvaluesobtainedineachschool. 1BshowstheGaussiandistribu urine samples.Figure spot bution ofindividualUICvaluesobtainedfrom Iodine nutrition inMexican schoolchildren p Amealco All Toliman San Joaquin de Amoles Pinal Pedro Escobedo Landa deMatamoros Jalpan deSerra Huimilpan El Marques Colon = 0.002). Correlation coefficients between UIC and betweenUICand coefficients =0.002).Correlation = 0.03), respectively (data not shown). On the other (datanotshown). On theother =0.03),respectively Differentlettersindicate statisticallysignificantdifferences(p<0.05), accordingtomedianvalueand multiplemediancomparisontests(Kruskal-Wallis andDunn’s tests). Figure 1A showsatypicalnon-Gaussiandistri Figure Table analysis 5 shows a multiple linear regression Municipality Schoolchildren (6-12yearsold) =111.36<0.05)andheightSDS(β 1488 142 147 149 144 159 149 141 149 158 150 n 287 (10-1205) (range), µg/L 352 (5-1519) 297 (5-1519) 519 (5-1213) 282 (5-1282) 228 (6-1250) 260 (5-1124) 265 (5-1164) 295 (5-1166) 294 (5-1039) 346 (8-1450) UIC, median = 0.008) and r = 0.30 =0.008)andr0.30 = 0.005) (Figure 2). 2). =0.005)(Figure 1544 150 149 153 154 161 156 150 153 164 154 n 290 (10-1205) 352 (5-1519) = 282 (5-1282) 260 (5-1124) 262 (5-1164) 294 (5-1166) 302 (5-1257) 346 (8-1450) 225 (6-1250) (range), µg/L 531 (5-1213) < 297 (5-1519) UIC, median - -

normally distributed(K2=5.198;p0.07). state schools(B). UICmedianvaluesobtainedfromeachschoolwere Mexican schoolchildren (A) and from median values of 50 elementary Figure 1. iodineconcentration(UIC)from1,544 Histogramsofurinary B A Frequency a,b b,c c,d c,d b,c b,c b,c b,c d a Frequency 100 200 300 12 0 0 4 8 0 0 Classification ofeachschoolaccordingtoUICmedian, µg/L Schools 50 n 5 5 5 5 5 5 5 5 5 5 200 100 400 50-99, 200 n 0 0 1 0 1 0 0 0 0 0 2 600 Arq Bras Metab. Endocrinol 2013;57/6 300 UIC (µg/L) UIC (µg/L) 100-199, 800 n 0 1 1 1 0 0 0 1 0 0 4 400 1000 200-299, 500 1200 19 n 2 3 2 2 3 3 3 1 0 0 1400 600 ≥ 300, 25 1600 n 3 1 1 2 1 2 2 3 5 5 700 A C straight-line representsthebest-fitlineobtainedbylinearregressionanalysis. social gap index. school (n=50), Eachdot represents oneelementary the Figure 3. iodine concentration (UIC)and Correlationbetweenmedianurinary Arq Bras Metab. Endocrinol 2013;57/6 national data that indicateasustainedelimination of consistentwithprevious ofthisstudyare The results DISCUSSION represents thebest-fitlineobtainedbylinearregressionanalysis. (B), prevalenceofstunting(C), andprevalenceofoverweight D).and obesity( school(n=50), Eachdotrepresentsoneelementary thestraight-line Figure 2. iodineconcentration(UIC)andmedianheightstandarddeviationscores(SDS)(A), Correlationsbetweenmedianurinary bodymass(BMI)SDS Prevalence of stunting (%) Median of heigth SDS Social gap index -2.0 -1.5 -1.0 -0.5 0.0 0.5 -1.5 -1.0 -0.5 10 20 30 0.0 0.5 1.0 1.5 0 0 0 0 100 100 100 Speaman r=-0.39;p0.003 200 200 200 Median UIC(µg/L) Median UIC(µg/L) Pearson r=0.36;p=0.005 Pearson r=0.41;p0.002 Median UIC(µg/L) 300 300 300 r 2 r = 0.13 2 400 400 = 0.16 400 500 500 500 600 600 600 700 700 700 D B iodine deficiency disorders (IDD)inMexico(3-5);ne iodine deficiencydisorders and inthislapse oftimeseveralanddramatic changes 14yearsago, performed thosestudieswere vertheless, SE: standarderror. *pvaluewascalculatedwithone-tailedtest. variables andUICasdependentvariable indicators, socialgapindex, andiodinecontentintablesaltasindependent Table 5. Bestmultiplelinearregressionmodelsbetweenglobalnutrition Independent variable R square Constant Social gapindex salt, ppm Iodine intable BMI SDS Height SDS Prevalence of overweight and obesity (%) Median of BMI SDS -2 10 20 30 40 50 -1 0 1 2 0 0 0 111.37 219.06 -47.19 1.52 0.26 100 100 β - Model 1 41.14 65.35 31.4 1.81 200 200 Iodine nutrition inMexican schoolchildren SE - Median UIC(µg/L) Median UIC(µg/L) Pearson r=0.47;p<0.001 300 300 0.001 0.004 0.001 0.07 0.20 p - r 2 400 400 = 0.22 Speaman r=0.41;p0.002 295.12 -46.98 99.95 1.31 0.20 β - 500 500 Model 2 35.63 75.10 54.01 1.88 SE - 600 600 0.009 0.000 0.10 0.25 0.04 700 700 p - 479 -

Copyright© ABE&M todos os direitos reservados. Copyright© ABE&M todos os direitos reservados. 480 the samplesize employedtocalculatethe medianUIC In addition,apotentiallimitation tothisstudyisthat influence iodizedsaltacquisition and/orconsumption. question socio-culturaland economic factorsthatcould inthisstudy,without iodine.Nevertheless, wedidnot opment. Asmentioned,we identified tablesaltsamples the lowerSGIandsubsequenthighersocialdevel food,considering ofiodine,suchasprocessed sources diction couldbeexplainedbytheaccesstootherdietary iodinecontent.Thisseeminglycontra had insufficient dine intake,although26%oftablesaltsamplesanalyzed andlowerSGI, had excessive io er stuntingprevalence iodine nutrition.Otherplaces,suchasColon,withlow of highqualityiodizedtablesalttoguaranteeadequate localitiesthatdependontheintake are notion thatthere the Thisfindingsupports vated SGIandundernutrition. ficiently iodizedtablesaltishigherinlocalitieswithele mote areas. foodinre the availabilityofprocessed which increases trading, andcommercial construction including road decades,ofthepublic infrastructure, ment, inrecent totheimprove couldberelated discrepancy apparent in the south of Italy (31). This in a study performed andcols. obtainedbyAghini-Lombardi to theresults tion forthealtitudeonUIC,whichisinaccordance in soil.However, wedidnotfindasignificantassocia iodineavailability factorsregarding bed asimportant geography andaltitudehavebeentraditionallydescri andpoverty,tient, andundernutrition respectively. The was associated with height SDS and intelligence quo (19) andIndia(30).Inthesestudies,iodinedeficiency Indonesia such as those from reports, ce with previous Thisfinding isinaccordan and stuntingprevalence. which hadthelowestmedianUICandhighestSGI in places such as Pinal de Amoles, relevant particularly iodinecontent.Thisis ples analyzedhadinsufficient ≥20%tablesaltsam placeswhere are because there intakecouldbeexplained 99 µg/L).Thisinsufficient iodineintake(medianUIC50- schools hadinsufficient gs. However, weshowedthat2of50(4%)elementary withourfindin iodine (6),andthisisinagreement 90% themarketedtablesaltsampleshave>15ppmof than thatguaranteesmore vely inanUSIprogram in Mexico isbasedalmostexclusi (8,29). IDDcontrol ofnutritionaldeficiencies and obesityareduction country, ofoverweight inprevalence withanincrease Currently, a nutrition transition Mexico is considered atanationallevel(8,29). in nutritionhaveoccurred Iodine nutrition inMexican schoolchildren As stated above, we found that the presence ofinsuf As statedabove,wefoundthatthepresence ------it isthefirsttimethatexcessiveiodineintakewasas andobesitywithUIC.Tooverweight ourknowledge, between BMI SDS, height SDS, significant correlation anaccurateassessmentofiodinestatus. prevent was lessthan30subjectsinafewlocations,whichcould assume that snack foods are iodinerich, too.Unfortu assume thatsnackfoodsare we Therefore, to employiodizedsalt in theirproducts. forthefoodindustry (33). InMexico,itiscompulsory foods richinenergy, carbohydrates,fat,andiodizedsalt thatsellsnack smallstores are schools,there ementary 533% (32).Besides,insideornearmostMexicanel increased availability ofindustrialized food products 1989to2004),the over aperiodof15years(from areas, 29%(29).Moreover,sumption dropped inrural andvegetablecon fruit 6.3%,whereas foods increased 1989to2006,theconsumptionofindustrialized from (8,29,32,33). Atanationallevel,itisestimatedthat, intheMexicanpopulation patterns changes indietary this associationcouldbeexplainedbythedramatic sociated withunhealthyweight.We hypothesizedthat tributes for almost a third of total iodineintake(38). tributes foralmost athird con since 2009,anditisestimated thatthismeasure withiodizedsaltis mandatory ofbread the fortification in New Zealand only (36). In this regard, iodine source as role seemtoplayanimportant products USA, dairy isnotmandatory. Onthe otherhand,inthe industry humanconsumptionorforfood dine tosaltfordirect cause in the USA andSwitzerland, the addition of io in someLatinAmericancountries,andthismaybe lowerthan (36,37).TheseUIClevelsare respectively is 211and120µg/L, median UIC in schoolchildren countries, suchas the USA and Switzerland, national or country. region Forexample,indeveloped a certain specificof should betakenintoaccountandthatare (34,35). 262 and166µg/L,respectively showed median UIC of USI program, comprehensive andVenezuela,American countries,Peru obtainedina otherLatin datafrom recent 40 ppmofiodine.More above In ourcaseonly7.8%oftablesaltsampleswere than50ppm ofiodine(5). table saltsampleshadmore 47%of an excessofiodinecontentintablesalt,where with iodine intake,medianUIC360µg/L,wasrelated this hypothesis. Moreover, in Brazil, excessive support andobesitySGI BMI SDS,heightoverweight However, thepositiveandsignificantassociationwith sumption ofindustrializedfoodinthestudiedschools. nately, wedidnotquantifytheacquisitionand/orcon On the other hand, we describe here apositiveand On theotherhand,wedescribehere There are other circumstances orvariablesthat othercircumstances are There Arq Bras Metab. Endocrinol 2013;57/6 ------schoolchildren, becausebothobesityandexcessivein schoolchildren, in toidentifysaltandiodinesources patterns the dietary Arq Bras Metab. Endocrinol 2013;57/6 4. 3. 2. 1. REFERENCES was reported. relevant tothisarticle nopotentialconflictofinterest Disclosure: -CONACYT-2009-117897). and Technology-Mixed Funds(grantnumberFOMIXQRO bytheNationalCouncilonScience This studywassupported andValeriaClaudia Alarcon fortheirtechnicalsupport. Perez, alsogratefultotheundergraduate iodinestudygroup, thors are Theau totranslate thetitleandabstractintoPortuguese. port andDr.determination Tercia CesariaReisdeSouzaforhersup versity, iodine for their technical advice and training in urinary and Dr. Uni Peruvian theCayetanoHeredia from AnaColarossi, Acknowledgments: wewouldliketothankDr. Pretell Eduardo consumption oftablesaltwithadequateiodinecontent. neededtoguaranteetheavailabilityand are programs educativeandnormative tion, intensiveandpermanent isapriority.trition bymeansofanUSIprogram Inaddi andkeep adequate iodine nu toreach iodine excretion formonitoringurinary generation ofanationalprogram and excessive).Becauseofthis,weconsiderthatthe of iodine intake (insufficient between the two extremes energy andiodizedsalt.Moreover, iscoexistence there the availabilityandconsumption of snackfood rich in tween UICandunhealthyweightcanbeexplainedby function. thyroid iodine excessinchildren needed todocumenttheimpactofbothobesityand studiesare (41).Further and autoimmunethyroiditis in cumulative subclinical hypothyroidism with increase other hand,excessiveiodineintakehasbeenrelated alterations(39,40).Onthe structure vels andthyroid (TSH)le­ hormone ofthyroid-stimulating an increase with function. On onehand,obesityhasbeenrelated onthyroid take ofiodinecouldhavedeleteriouseffects

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