Elevated manganeseandcognitiveperformanceinschool-agedchildren and theirmothers

Abstract

Background: Growing evidence suggests thatexcessmanganese(Mn)inchildrenisassociatedwithneuro behavioralimpairments.InBrazil,elevatedhairMnconcentrationswerereportedinchildrenlivingneara ferro-manganesealloyplant. Objectives: We investigatedthesechildren’sandcaregivers’cognitivefunctioninrelationtobio- indicators ofMnexposure. Methods: In thiscross-sectionalstudy,theWISC-IIIwasadministeredto83childrenagedbetween6and 12 years;theRavenProgressiveMatrixwasadministeredtotheprimarycaregivers(94%mothers),who likewiserespondedtoaquestionnaireonsociodemographicsandbirthhistory.Mninhair(MnH)and blood (MnB)andbloodlead(PbB)weremeasuredbygraphitefurnaceatomicabsorptionspectrometry (GFAAS). Results: Children’smeanMnBandMnHwere8.2 mg/L (2.7–23.4)and5.83 mg/g (0.1–86.68),respectively. Mean maternalMnHwas3.50 mg/g (0.10–77.45)andcorrelatedtochildren’sMnH(rho¼0.294, p¼0.010).Children’sMnHwasnegativelyrelatedtoFull-ScaleIntelligenceQuotient(IQ)andVerbalIQ; b coefficientsforMnHwere 5.78 (95%CI 10.71to 0.21) and 6.72( 11.81to 0.63),adjusted for maternaleducationandnutritionalstatus.MaternalMnHwasnegativelyassociatedwith performanceontheRaven’s(b¼ 2.69,95%CI 5.43 to0.05),adjustedforeducationyears,family incomeandage. Conclusions: These findingsconfirmthathighMnHinchildrenisassociatedwithpoorercognitive performance,especiallyintheverbaldomain.Primarycaregiver’sIQislikewiseassociatedtoMn exposure,suggestingthat,inthissituation,children’scognitionmaybeaffecteddirectlyandindirectly by Mnexposure.