www.jped.com.br
ORIGINAL
ARTICLE
Association
between
weather
seasonality
and
blood
parameters
in
riverine
populations
of
the
Brazilian
Amazon
夽
,
夽夽
Poliany
C.O.
Rodrigues
a,∗,
Eliane
Ignotti
c,
Sandra
S.
Hacon
baUniversidadedoEstadodeMatoGrosso(UNEMAT),FaculdadedeCiênciasdaSaúde(FCS),Cáceres,MT,Brazil
bFundac¸ãoOswaldoCruz(FIOCRUZ),EscolaNacionaldeSaúdePública(ENSP),DepartamentodeEndemiasSamuelPessoa
(DENSP),RiodeJaneiro,RJ,Brazil
cUniversidadedoEstadodeMatoGrosso(UNEMAT),ProgramadePós-Graduac¸aoemCiênciasAmbientais,Cáceres,MT,Brazil
Received28July2016;accepted16November2016 Availableonline23May2017
KEYWORDS
Ironhomeostasis; Biomarkers; Climatechange
Abstract
Objective: Toanalyzetheseasonalityofbloodparametersrelatedtoironhomeostasis,
inflam-mation,andallergyintworiverinepopulationsfromtheBrazilianAmazon.
Methods: Thiswasacross-sectionalstudyof120childrenandadolescentsofschoolage,livingin
riverinecommunitiesofPortoVelho,Rondonia,Brazil,describingthehematocrit,hemoglobin,
ferritin, serumiron, totalwhitebloodcellcount,lymphocytes,eosinophils,C-reactive
pro-tein,andimmunoglobulinElevelsinthedryandrainyseasons.Thechi-squaredtestandthe
prevalenceratiowereusedforthecomparisonofproportionsandmeananalysisusingpaired
Student’st-test.
Results: Hemoglobin(13.3g/dL)andhematocrit(40.9%)showedhigheraveragevaluesinthe
dryseason.Anemia prevalencewasapproximately4%and12%inthedry andrainy seasons,
respectively.Serumironwaslowerinthedryseason,withameanof68.7mcg/dL.The
preva-lenceofirondeficiencywas25.8%inthedryseasonand9.2%intherainyseason.Serumferritin
didnotshowabnormalvaluesinbothseasons;however,themeanvalueswerehigherinthedry
season(48.5ng/mL).Theparametersofeosinophils,lymphocytes,globalleukocytecount,
C-reactiveproteinandimmunoglobulinEshowednoseasonaldifferences.C-reactiveproteinand
immunoglobulinEshowedabnormalvaluesinapproximately7%and60%oftheexaminations,
respectively.
夽
Pleasecitethisarticleas:RodriguesPC,IgnottiE,HaconSS.Associationbetweenweatherseasonalityandbloodparametersinriverine populationsoftheBrazilianAmazon.JPediatr(RioJ).2017;93:482---9.
夽夽
Thisarticleispartofthedissertation‘‘Subclinicalalterationsinschoolchildrenexposedtoairpollutantsderivedfromforestfiresinthe BrazilianAmazon’’byRodrigues,PCO,whichwaspresentedin2012atEscolaNacionaldeSaúdePúblicaandwasfundedbytheINOVA/ENSP andCNPq/PapesVIprojects(407747/2012-5).
∗Correspondingauthor.
E-mail:polianyrodrigues@unemat.br(P.C.Rodrigues).
http://dx.doi.org/10.1016/j.jped.2016.11.012
0021-7557/©2017SociedadeBrasileiradePediatria.PublishedbyElsevierEditoraLtda.ThisisanopenaccessarticleundertheCCBY-NC-ND
Conclusion: Hematologicalparametersoftheredcellseriesandbloodironhomeostasishad
seasonalvariation,whichcoincidedwiththedryseasonintheregion,inwhichanincreasein
atmosphericpollutantsderivedfromfiresisobserved.
©2017SociedadeBrasileiradePediatria.PublishedbyElsevierEditoraLtda.Thisisanopen
accessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/
4.0/).
PALAVRAS-CHAVE
Homeostasiadoferro; Biomarcadores; Mudanc¸asclimáticas
Relac¸ãodasazonalidadeclimáticacomparâmetrossanguíneosderibeirinhos residentesnaAmazôniabrasileira
Resumo
Objetivo: Analisar asazonalidade climáticade parâmetrossanguíneosrelacionadosà
home-ostasedoferro,inflamac¸ãoealergiaemduaspopulac¸õesribeirinhasdaAmazôniaBrasileira.
Método: Realizou-seum estudo transversalem 120 crianc¸as eadolescentesem idade
esco-lar, residentes em comunidades ribeirinhas de Porto Velho, Rondônia. Foram analisados
hematócrito, hemoblogina,ferritina,ferro sérico,leucometriaglobal,linfócitos,eosinófilos,
proteínaC-reativaeImunoglobulinaEnasestac¸õessecaechuvosa.Utilizou-seoqui-quadrado
earazãodeprevalênciaparaacomparac¸ãodasproporc¸ões,alémdotestetdestudentpareado
paraaanálisedemédias.
Resultados: Hemoglobina (13,3g/dL) e hematócrito (40,9%) apresentaram maiores valores
médios no período de seca. A prevalência de anemia foi cerca de4% e 12%na seca e na
chuva, respectivamente. O ferro sérico foi menor noperíodo de seca com média de 68,7
mcg/dL.Aprevalênciadedeficiênciadeferrofoiemmédia25,8%,naseca,e9,2%,nachuva.
Aconcentrac¸ãoséricadeferritinanãoapresentouvaloresalteradosemambososperíodos,no
entantoosvaloresmédiosapresentaram-semaiselevadosnaseca(48,5ng/mL).Osparâmetros
doseosinófilos,linfócitos,leucometriaglobal,proteínaC-reativaeImunoglobulinaEnão
apre-sentaramdiferenc¸assazonais.AProteínaC-reativaeaImunoglobulinaEapresentaramvalores
alteradosemcercade7%e60%dosexamesrealizados,respectivamente.
Conclusão: Osparâmetroshematológicosdasérievermelhaeahomeostasiaferrosanguíneo
apresentaramvariac¸ãosazonal,quecoincidecomoperíododesecanaregião,noqual
observa-seaumentodospoluentesatmosféricosderivadosdasqueimadas.
©2017SociedadeBrasileiradePediatria.PublicadoporElsevierEditoraLtda.Este ´eumartigo
OpenAccesssobumalicenc¸aCCBY-NC-ND(http://creativecommons.org/licenses/by-nc-nd/4.
0/).
Introduction
In 2010, Brazil faced a severe drought throughout the country.Intheso-called‘‘deforestationarc,’’thedrought directly interfered in the increase of forest fires. In the municipalityofPortoVelho,thehighestproportionofforest firesoccurredinAugustandSeptemberand,consequently,a highconcentrationofthemeanlevelsofparticulatematter (PM)wasobserved,recordedbytheairmonitoringstation inPortoVelho,withanapproximatepeakof 240g/m3in
the month of September. In 2011, PM concentrations did notexceedthemonthlymeanof10g/m3duringtheentire
rainyseason.1
The scientific literaturecurrently presentsseveral tox-icologicalmechanismsthroughwhich PMcancausehealth damage,mainly damagetotherespiratory and cardiovas-cular systems, triggered by inflammatory, immunological, andgenotoxicityresponses.2Theeffectsinvolvean
inflam-matory response with a serum increase in C-reactive
protein and cytokines3---5 and increased airway reactivity
through immunoglobulins,6 as well as alterations in
sev-eralhematologicalparameterssuchasincreasedeosinophil adhesion7andalteredleukocytecount,8,9hemoglobin,and
hematocrit.10,11
The Brazilian Amazon region historically suffers from forestfiresduring the dry season. In theseregions, some ecologicalstudies haveshown thatbiomassburning isone ofthemainriskfactorsforincreasedmorbidityand mortal-itydue torespiratorydiseases inchildrenandtheelderly, especiallyin the ‘‘deforestation arc.’’12---14 More recently,
mortalityrates fromcardiovascular disease in theelderly wereassociatedwithexposuretoPM2.5.15
parametersrelated tothis seasonalfeature of the region wereretrieved.
Material
and
method
Studydesign
A cross-sectional descriptive study, with a quantitative approach, was carried out in schoolchildren living in the communitiesofCuniãand Belmont,locatedin thecity of Porto Velho, Rondônia, in the southern Brazilian Amazon region,comparingthe valuesofbloodparametersin rela-tiontotheseasonalexposuretopollutantsfromforestfires intheregion.
Studypopulationandarea
The study population comprised individuals from a cen-sus carriedout in the communitiesof Cuniã andBelmont betweenJuneandSeptemberof2010.Childrenand adoles-centsbetween theagesof 6and 16years,whohad been livinginthecommunityforatleastoneyear,were consid-eredeligiblefor thestudy andwererecruited toundergo bloodtestsintwostages:thefirstinthedryseason (Octo-berandNovember,2010)andthesecondintherainyseason (May,2011).Onlyindividualswhoparticipatedinbothstages andwhodidnothaveaninfectiousdiseaseatthetimeofthe examinations(cold, flu, andmalaria, amongothers)were included,totaling120individuals.
The monthsofthe yearweregrouped asdry andrainy months,basedonthemeanmonthlyrainfallrecordsofthe NationalInstituteofMeteorology.The dryseasonrefersto themonthsofJunetoNovemberof2010.Therainyseason referstoDecemberof2010throughMayof2011.
Theclimaticseasonalvariationisacharacteristicfeature oftheregion,beinglimitedtotwodefinedseasons:dryand rainy.Thesecommunitiesarelocatedinisolatedruralareas; sincethe1970s,theysufferthedirectinfluenceofpollutants resultingfromforestfiresintheregionduringthedry sea-son.AlthoughtheBelmontcommunitysufferstheinfluence ofurban pollutants, both communitiesarevery similarin theirhabitsandlivingconditions.
The riverinecommunityof Belmontislocatednearthe fluvial port of Porto Velho and is distributed around the ‘‘Belmontroad’’,which is approximately20km long. The community,despite itsrural characteristics, suffers great urban influence due to its proximity to downtown Porto Velho(approximately5km).Theextractivereserve(Resex) ofCuniãislocatedatapproximately190kmfromthe cap-ital, Porto Velho.As the accessto the community occurs basicallythroughtheriver,thisresultsinthesemi-isolation ofthe population,which isevenworse inthe dryseason, especiallytermsofmedicalcare.16
Bloodtests
Thebloodandserumsampleswerecollectedbytechnicians fromthe clinical laboratory of the Hospital 9de Julho in Porto Velho, and processed in an automated device. For blood analysis, an automated hemogram was performed
usingtheelectricalimpedancemethod,fromwhich hema-tocrit, hemoglobin, general leukometry, eosinophils, and lymphocytes were selected. Hematocrit and hemoglobin wereselectedtohelpevaluateironhomeostasis.Thewhite blood cell parameters --- general leukometry, eosinophils, andlymphocytes---wereselectedtocomplementthe evalua-tionoftheindividuals’inflammatoryandallergicprocesses. Thefollowingparameterswereanalyzedfromtheserum: iron, ferritin,C-reactive protein(CRP) and immunoglobu-lin E (IgE). The iron homeostasis parameters, serum iron andferritin,wereobtainedusingthemodifiedGoodwinand immunoturbidimetry methods, respectively. CRP measure-mentwasobtainedusingthelatexagglutinationmethodand wasusedforinflammationassessment.Fortheallergy eval-uation,multipleIgEforinhalantallergens(HX2)wasused, whichincludessensitizationbyhousedust(H1),dustmites (D1andD2),andcockroaches(I6),andthemethodof analy-sisusedwasenzymaticfluorescence---Immunocap(Thermo FisherScientificInc,Uppsala,Sweden).
Statisticalanalysis
Databaseswerecreatedcontainingalltheinformation col-lected on the field during the two campaigns that were carriedout.Thechi-squaredtestandprevalenceratiowere usedforthecomparisonofproportions,in additiontothe pairedStudent’st-testfortheanalysisofmeansduringthe dry and rainy seasons. Comparisonsbetween the commu-nities were made using Student’s t-test for independent samples.Theanalyseswereperformedusingthestatistical softwareSPSS(IBMCorp.Released2011.IBMSPSSStatistics forWindows,version20.0,NY,USA).
Protocols
ThestudywasapprovedbytheEthicsCommitteeofEscola Nacional de Saúde Pública da Fundac¸ão Oswaldo Cruz (CEP/ENSP89/11 ---CAAE 00830031000-1).All participants had the consentof a parent or guardian, who signed the freeandinformedconsentform.
Results
Generalcharacteristicsofthestudypopulation
Atotalof120childrenandadolescentsparticipatedinthe collectionsinbothperiods,totaling55testscarriedoutin Belmont and65in Cuniã.Approximately 70%of the study population consisted of children (>12 years of age); the meanagewas10yearsinthedryseasonand11yearsinthe rainyseasoninbothcommunities.Bothcommunitieshada higher proportionof female subjects, totaling 52% of the populationofBelmontand60%ofthepopulationofCuniã. Thediagnosisofintestinalparasitosiswaspositivein38%of thepopulation,43%forCuniãand31%forBelmont.
Bloodparameters
43.00 14.00
13.75
13.50
13.25
13.00
12.75 42.00
41.00
40.00
39.00
38.00
Dry season 2010 Rainy season 2011 Dry season 2010 Rainy season 2011 Legend Belmont Cuniã Joint communities
95%CI - Hematocr
it, %
95%CI - Hemoglobin (g/dL) (g%)
Figure1 Distributionofvaluesandconfidenceintervals(CI)forhematocritandhemoglobin,accordingtocommunityandperiod.
*Statisticallysignificantresultforcomparisonofmeansbetweentheperiods(dryandrainyseasons)throughpairedStudent’st-test
andp-value <0.05.#Statistically significantresultfor comparisonofmeansbetween thecommunities (in eachperiod)through
Student’st-testforindependentsamplesandp-value<0.05.
andfor bothcommunitiesconsideredtogether. Theglobal means, approximately 40.9% in the dry season and39.6% intherainyseason,wereconsideredtobewithinthe nor-malrange.Asforthedryseason,therewasadifferencein hematocritvaluesbetweenthecommunities.Regardingthe globalhemoglobinparameters,forthegroupedcommunities and for the Belmont community, astatistically significant decreasewasobservedintherainyseason.Thehighest con-centrations of hemoglobin in blood were observed in the Belmont community in both periods; however, a statisti-callysignificantdifferencewasobservedinconcentrations betweencommunitiesonlyinthedryseason(Fig.1).
The global hemoglobinmeans inthedry andrainy sea-sons werewithinthe normalrange andthe prevalenceof anemiawashigherin Cuniã.Inthe dryseason,the preva-lenceofanemiawasaround4%;intherainyseason,itwas 12%forallcommunities.Itwasobservedthatthe probabil-ityofanemiaoccurrencewas35%lowerinthedry season (95%CI:0.1---0.9).
Considering both communities together, serum ferritin concentrationsshowedastatisticallysignificantdecreasein therainyseason.Themeanconcentrationinthedryseason was48.5ng/mL,whileintherainyseasonitwas41.2ng/mL. Noteventheminimumvaluesinbothperiodscanbe consid-ered outsideof the normalparameters;nevertheless, the serumlevelsobserved inthe communityofBelmont were higherthaninthecommunityofCuniãandinthegroupof thecommunities,inbothperiods.Astatisticallysignificant differencewas observed in serum ferritin levelsbetween thecommunitiesin boththedryandrainyseasons.Serum iron,with global means of 68.7mcg/dL in the dry season and77.5mcg/dLintherainyseason,showedastatistically significantincreaseintherainyseasonwhenthe communi-tieswere considered asa groupand in thecommunityof Belmont(Fig.2).
The mean prevalence of altered values, which consti-tuteirondeficiency, was25.8%inthedryseasonand9.2% intherainyseason.Bothcommunitieshadahigher preva-lence of altered values in the dry season; however, the Belmontcommunity hada higherprevalence of iron defi-ciency(approximately33%inthedryseasonand11%inthe rainyseason).
Thevaluesforleukometry,eosinophils,andlymphocytes didnotshowaseasonaldifferenceforthecommunities con-sideredasagrouporseparately.Inthedryseason,aglobal meanof 7405.8 mm3 was observed,whereas in the rainy season, the mean was 7172.5mm3. Eosinophilia occurred inapproximately70%of thetestsinbothperiodsfor both communities,as well asfor the communities asa group. The global means werearound9.9% in the dry and10.2% intherainyseason.Astatisticallysignificantdifferencewas observedbetweenthecommunitiesduringthedryseason. Theglobalmeansforthedistributionoflymphocytevalues arearound36.1%inthedry seasonand35.1%intherainy season(Fig.3).
TheproportionofalteredCRPtestswasabout7%intotal, andBelmontshowedahigherproportioninthedryseason, whileCuniãhadahigherproportionintherainyseason.IgE wasaltered(reagent)inapproximately60%ofthetestsin bothseasonsandcommunities,withagreaterprobabilityof alterationintherainyperiodinbothcommunities(Table1).
Discussion
85 70.00
60.00
50.00
40.00
30.00
Legend Belmont Cuniã Joint communities 80
75
70
65
60
55
Dry season 2010 Dry season 2010
95%CI - Serum iron (mcg/dL)
95%CI - Ferritin (ng/mL)
Rainy season 2011 Rainy season 2011
Figure2 Distributionofvaluesandconfidenceintervals(CI)for serumironandferritin,accordingtocommunityandperiod.
*Statisticallysignificantresultforcomparisonofmeansbetweentheperiods(dryandrainyseasons)throughpairedStudent’st-test
andp-value<0.05.#Statisticallysignificant resultforcomparison ofmeansbetween thecommunities (ineachperiod) through
Student’st-testforindependentsamplesandp-value<0.05.
Table1 Proportion ofalteredtests forC-reactiveprotein andmultipleIgEfor inhalants,accordingtothecommunityand
period.
Dryseason Rainyseason 2
(p-value)
Prevalenceratio
(95%CI)
n % n %
C-reactiveprotein Belmont
Altered 6 10.91 3 5.45 1.08 2.00
Normal 49 89.09 52 94.55 (0.489) (0.5---7.6)
Total 55 100.00 55 100.00
Cuniã
Altered 2 3.08 3 4.62 0.20 0.7
Normal 63 96.92 62 95.38 (1.000) (0.12---3.9)
Total 65 100.00 65 100.00
Global
Altered 8 6.67 6 5.00 0.30 1.33
Normal 112 93.33 114 95.00 (0.784) (0.5---3.7)
Total 120 100.00 120 100.00
MultipleIgEforinhalantallergens Belmont
Reagent 36 65.45 37 67.27 0.04 0.97
Non-reagent 19 34.55 18 32.73 (1.000) (0.7---1.3)
Total 55 100.00 55 100.00
Cuniã
Reagent 38 58.46 39 60.00 0.03 0.97
Non-reagent 27 41.54 26 40.00 (1.000) (0.7---1.3)
Total 65 100.00 65 100.00
Global
Reagent 74 61.67 76 63.33 0.07 0.97
Non-reagent 46 38.33 44 36.67 (0.894) (0.8---1.2)
Total 120 100.00 120 100.00
8500.0 Legend Belmont Cuniã Joint communities 8000.0
7500.0
7000.0
6500.0
14
12
10
8
6
38
36
34
32
Dry season 2010 Rainy season 2011
Dry season 2010
95%CI - Eosinophils (%)
95%CI - Global leukometry (mm
3)
95%CI - L
ymphocytes (%)
Rainy season 2011
Dry season 2010 Rainy season 2011
Figure 3 Distribution of the values of global leukometry,
eosinophils, and lymphocytes according to community and
period.#Statisticallysignificantresultforcomparisonofmeans
between thecommunities (ineach period)through Student’s
t-testforindependentsamplesandp-value<0.05.
observed an increase in ferritin levels in healthy workers responsibleforheatingapartmentsusingcoalinTurkey.
Ghio et al.17 showed higher serum ferritin levels in
pulmonary lavage of individuals with lung inflammation when comparedto individuals without inflammation. The inverselyproportionalassociationobservedmayberelated tothemobilizationofironstoresbytheincreased intracellu-laruseofiron.Ferritin,althoughconsideredagoldstandard for thequantification ofiron stores,may increase due to inflammatoryorinfectiousprocesses,whichdoesnotmean thatthereisanincreaseinironstores.19Inturn,iron,which
ishighlyusedinmetabolicreactions andin theformation ofbloodelements,canbeacutelyreducedinthepresence of infections or inflammation.20 The blood parameters of
redbloodcells,hemoglobin,andhematocrit,showeda sea-sonalvariationwithanincreaseinthedryseason,whenthe concentrationofPM is usuallyhigher.This result corrobo-ratesthestudiesbySorensenetal.,11inGermany,whofound
anincreaseinthesameparametersinuniversitystudents, relatedtohighconcentrationsofPM2.5,andNeufeldetal.,10 inIndia, who alsoobserved an increase in the proportion ofbloodhemoglobinandhematocritinwomenusingindoor woodstoves.Thisincreasehasbeeninterpretedasa func-tionaladaptationofthebodyinresponsetotissuehypoxia20
caused by the multi-element nature of PM, which could mask,forinstance, thediagnosisof anemia.This increase inhemoglobinandhematocritisalsoassociatedwitha pos-siblehemoconcentration,21 suggestinganincreaseinblood
viscosityatthistime.
Another important findingis the fact that hematocrit, hemoglobin, and ferritin values were higher in the Bel-montcommunity,togetherwithahigherprevalenceofiron deficiency,suggestingagreateruseofironstoresby individ-ualsin thiscommunity.Thisfindingmayberelatedtothe influenceofurbanpollutants inthecommunity,aswell as exposuretoforestfires,sinceBelmontisclosertothecity ofPortoVelhoandthecity’sriverport,whichmaysuggest greaterexposuretootherpollutants,mainlyproductsfrom burningfossilfuels,incontrasttothecommunityofCuniã, whichislocatedinthemiddleoftheforestandhasnocars. Globalleukometry,aswellaslymphocytes,eosinophils, multiple IgE, and CRP, did not show seasonal variation. Theassociationbetweenhematologicalparametersofwhite bloodcellsandairpollutionstillremainscontradictoryinthe scientificliterature.WhileSteinviletal.22foundno
associa-tionbetweenpollutionandalterationsintheseparameters inyoungadultsinIsrael,astudycarriedoutwithchildren andadolescentsinIran byPoursafa etal.9 foundan
asso-ciationbetween atmospheric pollutionand an increase in globalleukometry,forinstance.Moreover,the hematologi-calparametersofthewhitebloodcellsareverynon-specific with respect to diagnoses. In general, these parameters concernthe individual’s overall nutritionalstatus andthe presenceofsomeinflammatoryorinfectiousprocess,such as allergies, viruses, and even intestinal parasitosis.23,24
Therefore,themain reasonfor thisfindingmaybe associ-atedtothefactthatalltheseparametersundergosignificant changesinthepresenceofintestinalparasitosis,sincethe studiedpopulation hasa high andconstant prevalence of intestinalparasites.
Amin,6 in a review on the role of mast cells in allergic
inflammation,indicatedthatcontinuousexposureto pollu-tantsmaypromotetheconstantsynthesisofIgE.However, ZavadniakandRosário25discussedapossibleblockinginthe
productionof allergen-specificIgEinthe presenceof par-asites due tothe production of T-cells. Medeiros et al.26
observed lowerreactivity in skin tests, considered asthe mostspecificallergytests,inasthmaticchildrenwith par-asitosis.Moreover, Genov et al.27 reported that exposure
to helminths would cause cross-reactivity by stimulating IgE-mediatedimmune responsesdue tothehigh similarity betweentropomyosin(aproteininvolvedinvertebrateand invertebratemusclecontractions,knowntobehighly aller-genic)ofhelminthsandseveralallergens.
TheresultsfoundforCRPinthepresentstudydifferfrom otherthat showedanassociation betweenthe increasein CRP and the acute effect of air pollution. These effects wereobserved mainly in adults and elderly patients with cardiovasculardiseases,4,5 in whom ahigh level of CRP is
expected,aswellasgreatersusceptibilitytoairpollutants duetobodyfragilitycausedbythedisease.However,Shima et al.3 observed a significant increase in CRP in healthy
schoolchildren.Conversely,Steinviletal.,22Rudezetal.,28
andHildebrandtetal.29alsofoundnosignificantalterations
inserumCRPconcentrationsinhealthyindividuals,evenin highatmosphericpollutionenvironments,corroboratingthe findingsofthepresentstudy.Thisfactwouldbeexplained by a possible different systemic relationship in the regu-lation of inflammation in healthy and sick individuals, in addition to the fact that CRP does not participate in all aspectsandstagesofinflammation.5,30Anotherexplanation
fortheabsenceofCRPalteration,eveninthepresenceof reagent IgE and eosinophilia, may be relatedto its short half-lifeofjustafewhours,whilethehalf-lifeoftheother parameterslastsfordays.
Amongthelimitationsofthisstudyareitscross-sectional designandtheecologicalnatureoftheassociations,while thenumberoftestsperformedmayhavebeeninsufficient todemonstratetheseasonalalterations.Anotherimportant point is related to the high prevalence of intestinal par-asitosis, the chronic nature of other exposures, and the nonspecific character of some biomarkers that may have maskedorinfluencedsomeofthebloodparameters, espe-ciallythoserelatedtoallergyandinflammation.Moreover, theisolationof somecommunitiesat certaintimesofthe year (Cuniã in the dry season and Belmont in the rainy season),as well as the low socioeconomic status of both communitiescanmake itdifficult tohave accesstofood, physicians,andmedication,negativelyinfluencingthe pop-ulationhealthstatus.
The resultsof thisstudy providehealth assessmentsat twoverycharacteristicmomentsof theBrazilianAmazon, allowing an overview of the possible subclinical effects occurring during periods of more and fewer forest fires, describing their particularities in two riverine communi-tiesof PortoVelho. However, it is necessary to carryout moredetailedanalysesofthevariablesinvestigatedinthe study and a better understanding of the processes that interfere with the dynamics of the health and environ-mentsituationintheriverinecommunitiesoftheBrazilian Amazon.
Itcanbeconcludedthatthehematologicalredbloodcell parameters and blood iron homeostasis of schoolchildren living intheBrazilian Amazonshowedseasonalvariations, which coincides withthe dry season in the region, when there is an increase in atmospheric pollutants originating from fires.CRP, IgE,global leukometry, lymphocytes, and eosinophilswerenotsufficientlysensitiveforthescreening ofsubclinicaleffectsrelatedtoforestfires.
Conflicts
of
interest
Theauthorsdeclarenoconflictsofinterest.
Acknowledgements
TotheCuniãandBelmontcommunitiesandtheentireteam oftheInovaENSPproject.
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