Polychlorinated biphenyls and thyroid hormone serum concentrations among people living in highly polluted area: a cross-sectional population-based study

Background: Polychlorinatedbiphenyls(PCBs)mayinteractwithseveralthyroidfunctions.Severe environmentalpollutionbyPCBshasbeenobservedinBrescia,Italy,duetothepresenceofafactory that producedthesecompoundsuntil1984. Objectives: WeaimedtoinvestigatethecorrelationbetweenserumlevelsoftotalPCBsandPCB153and thyroidhormoneserumlevelsinadultsinacross-sectionalpopulation-basedstudy. Methods: A totalof527subjectswereenrolled;theywereface-to-faceinterviewedabouttheirhistory of thyroiddiseaseandprovidedabloodsampleunderfastingconditions.Theserumlevelsoffreeand totaltriiodothyronine(FT3andTT3),thyroxine(FT4andTT4)andthyroid-stimulatinghormone(TSH), anti-thyroperoxidase(anti-TPO)andanti-thyroglobulin(anti-TGA),andlipid-adjustedtotalPCBsand PCB 153weredetermined. Results: There wasnostatisticallysignificantdifferenceintotalPCBandPCB153concentrationsin subjectswithandwithoutthyroiddisease.Inverse,weak,statisticallysignificantcorrelationswere foundbetweentotalPCBsandFT3(Spearman’s r ¼ 0.09) andbetweentotalPCBsandPCB153andTSH (Spearman’s r ¼ 0.16and 0.12,respectively).However,multipleregressionanalysiswithFT3andTSH serum levelsasdependentvariablesandtotalPCBsandPCB153serumlevelsaspredictors,including age, genderandBMI,showedapositive,ratherthannegative,associationofPCBsandPCB153withFT3 and noassociationwithTSH. Conclusions: This studydoesnotsupportthehypothesisthatrelativelyhighPCBenvironmental exposurecandeterminesubstantialalterationsinthyroidfunctionamongadultpeople.