Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies Rodriguez-Carrillo, Andrea Salamanca-Fernandez, Elena den Hond, Elly Verheyen, Veerle J. Fábelová, Lucia Murinova, Lubica Palkovicova Pedraza-Díaz, Susana Castaño, Argelia García-Lario, Jose Vicente Remy, Sylvie Govarts, Eva Schoeters, Greet Olea Serrano, Nicolás Freire, Carmen Fernández Cabrera, Mariana Fátima Perfluoroalkyl substances Background: Perfluoroalkyl substances (PFAS) and phthalates are synthetic chemicals widely used in various types of consumer products. There is epidemiological and experimental evidence that PFAS and phthalates may alter thyroid hormone levels; however, studies in children and adolescents are limited. Aim: To investigate the association of exposure to PFAS and phthalate with serum levels of thyroid hormones in European adolescents. Methods: A cross-sectional study was conducted in 406 female and 327 male adolescents (14–17 years) from Belgium, Slovakia, and Spain participating in the Aligned Studies of the HBM4EU Project (FLEHS IV, PCB cohort, and BEA, respectively). Concentrations of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA), free thyroxine (FT4), free triiodothyronine (FT3), and thyroid-stimulating hormone (TSH) were measured in sera from study participants, and urinary metabolites of six phthalates (DEP, DiBP, DnBP, BBzP, DEHP, and DiNP) and the non-phthalate plasticizer DINCH® were quantified in spot urine samples. Associations were assessed with linear regression and g-computational models for mixtures. Effect modification by sex was examined. Results: In females, serum PFOA and the PFAS mixture concentrations were associated with lower FT4 and higher FT3 levels; MEP and the sums of DEHP, DiNP, and DINCH® metabolites ( ∑DEHP, ∑DiNP, and ∑DINCH) were associated with higher FT4; ∑DEHP with lower FT3; and the phthalate/DINCH® metabolite mixture with higher FT4 and lower FT3. In males, PFOA was associated with lower FT4 and the PFAS mixture with higher TSH levels and lower FT4/TSH ratio; MEP and ∑DiNP were associated with higher FT4; and MBzP, ∑DEHP, and the phthalate/DINCH® metabolite mixture with lower TSH and higher FT4/TSH. PFOA, mono-(2-ethyl-5-hydroxyhexyl) phthalate (OH-MEHP), mono-(2-ethyl-5-oxohexyl) phthalate (oxo-MEHP), and monocarboxyoctyl phthalate (MCOP) made the greatest contribution to the mixture effect. Conclusions: Results suggest that exposure to PFAS and phthalates is associated with sex-specific differences in thyroid hormone levels in adolescents 2023-09-26T10:08:14Z 2023-09-26T10:08:14Z 2023-08-19 journal article Rodríguez-Carrillo A, Salamanca-Fernández E, den Hond E, Verheyen VJ, Fábelová L, Murinova LP, Pedraza-Díaz S, Castaño A, García-Lario JV, Remy S, Govarts E, Schoeters G, Olea N, Freire C, Fernández MF. Association of exposure to perfluoroalkyl substances (PFAS) and phthalates with thyroid hormones in adolescents from HBM4EU aligned studies. Environ Res. 2023 Aug 19;237(Pt 1):116897. doi: 10.1016/j.envres.2023.116897. Epub ahead of print. PMID: 37598845. https://hdl.handle.net/10481/84668 10.1016/j.envres.2023.116897 eng open access Elsevier