Early life exposure to perfluoroalkyl substances (PFAS) and ADHD: a meta-nalysis of nine european population-based studies
Introduction: To date, the evidence for an association between perfluoroalkyl substances (PFAS) exposure and attention deficit and hyperactivity disorder (ADHD) is inconclusive. Objective: We investigated the association between early life exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), and ADHD in a collaborative study including nine European population-based studies, encompassing 4,826 mother-child pairs. Methods: Concentrations of PFOS and PFOA were measured in maternal serum/plasma during pregnancy, or in breast milk, with different timing of sample collection in each cohort. We used a validated pharmacokinetic model of pregnancy and lactation to estimate concentrations of PFOS and PFOA in children at birth and at 3, 6, 12, and 24 months of age. We classified ADHD using recommended cutoff points for each instrument used to derive symptoms scores. We used multiple imputation for missing covariates, logistic regression to model the association between PFAS exposure and ADHD in each study, and combined all adjusted study-specific effect estimates using random-effects meta-analysis. Results: A total of 399 children were classified as having ADHD, with a prevalence ranging from 2.3% to 7.3% in the studies. Early life exposure to PFOS or PFOA was not associated with ADHD during childhood [odds ratios (ORs) ranging from 0.96 (95% CI: 0.87, 1.06) to 1.02 (95% CI: 0.93, 1.11)]. Results from stratified models suggest potential differential effects of PFAS related to child sex and maternal education. Conclusion: We did not identify an increased prevalence of ADHD in association with early life exposure to PFOS and PFOA. However, stratified analyses suggest that there may be an increased prevalence of ADHD in association with PFAS exposure in girls, in children from nulliparous women, and in children from low-educated mothers, all of which warrant further exploration. https://doi.org/10.1289/EHP5444. ; This research was primarily supported by a grant from the European Community's Seventh Framework Program (FP7/2007–2013) under grant agreement Developmental Neurotoxicity Assessment of Mixtures in Children (DENAMIC) no. 282957. M.-A.V. is the recipient of a Research Scholars J1 Award from the Fonds de recherche du Québec–Santé. Norwegian Human Milk Study (HUMIS) research was funded by a grant from the Norwegian Research Council, under the NEVRINOR program grant agreement no. 226402; by PROTECTion against Endocrine Disruptors: Detection, mixtures, health effects, risk assessment and communication, and by European Union (EU) Horizon 2020 Marie Skłodowska-Curie Actions Innovative Training Networks–European Training Network no. 722634. We thank Anteneh Desalegn for his work in the HUMIS biobank. The study was approved by the Regional Ethics Committee for Medical Research in Norway (ref. S-02122) and the Norwegian Data Inspectorate (refs. 2002/1398), and participation did not occur until after informed consent was obtained. The Infancia y Medio Ambiente (INMA) study was funded by grants from the EU: NEWGENERIS FP6-2003-Food-3-A-016320, FP7-ENV-2011 cod 282957, HEALTH.2010.2.4.5-1; and by grants from Spain: Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041, FIS-FEDER:PI 03/1615, PI04/1509, PI04/1112, PI04/1436, PI04/1931, PI/04/2018, PI05/1079, PI05/1052, PI06/0867, PI06/1213, PI07/0314, PI/08/1151, PI09/02647, FIS-PI041436, FIS-PI081151, FISS-PI042018, FISS-PI09/02311, FISPI06/0867 FIS-PS09/00090, FIS-PI07/0252, PS09/00090, PI11/01007, PI11/02591, PI11/02038, PI13/1944, PI13/2032, PI14/00891, PI14/01687, PI16/1288, PI17/00663 and Miguel Servet-FEDER: CP11/00178, MS13/00054, and MSII16/00051), Generalitat de Catalunya-CIRIT 1999SGR 00241, La Fundació La Marató de TV3 (090430), Alicia Koplowitz Foundation 2017, Conselleria de Sanitat Generalitat Valenciana, Department of Health of the Basque Government (2005111093 and 2009111069), Provincial Government of Gipuzkoa (DFG06/004 and DFG08/001), Obra Social Cajastur, Universidad de Oviedo, Consejería de Salud de la Junta de Andalucía (grant no. 183/07), EU Commission (QLK4-1999-01422, QLK4-2002-00603, and CONTAMED FP7-ENV-212502), and Fundación Roger Torné. Global Health Institute Barcelona (ISGlobal) is a member of the CERCA Programme, Generalitat de Catalunya. A full roster of the INMA Project Investigators can be found at http://www.proyectoinma.org/presentacion-inma/listadoinvestigadores/en_listado-investigadores.html. The INUENDO study was funded by the European Commission's Seventh and Fifth Framework Programmes (FP7-ENV-2008-1-226217 and QLK4-CT-2001-00202). The polychorinated biphenyl (PCB) cohort was funded by the U.S. National Institutes of Health (grants R01 CA096525 and R03 TW007152), the EU Seventh Framework Programme FP7/2007-2023 (grant agreement OBELIX, no. 227391), Slovak Research and Development Agency (grants APVT-21-016804, APVV-0571-12, APVV-0444-11), and by the ITMS project (no. 26240120033) based on the supporting operational research and development program from the European Regional Development Fund. ; This research was primarily supported by a grant from the European Community's Seventh Framework Program (FP7/2007–2013) under grant agreement Developmental Neurotoxicity Assessment of Mixtures in Children (DENAMIC) no. 282957. M.-A.V. is the recipient of a Research Scholars J1 Award from the Fonds de recherche du Québec–Santé. Norwegian Human Milk Study (HUMIS) research was funded by a grant from the Norwegian Research Council, under the NEVRINOR program grant agreement no. 226402; by PROTECTion against Endocrine Disruptors: Detection, mixtures, health effects, risk assessment and communication, and by European Union (EU) Horizon 2020 Marie Skłodowska-Curie Actions Innovative Training Networks–European Training Network no. 722634. We thank Anteneh Desalegn for his work in the HUMIS biobank. The study was approved by the Regional Ethics Committee for Medical Research in Norway (ref. S-02122) and the Norwegian Data Inspectorate (refs. 2002/1398), and participation did not occur until after informed consent was obtained. The Infancia y Medio Ambiente (INMA) study was funded by grants from the EU: NEWGENERIS FP6-2003-Food-3-A-016320, FP7-ENV-2011 cod 282957, HEALTH.2010.2.4.5-1; and by grants from Spain: Instituto de Salud Carlos III (Red INMA G03/176 and CB06/02/0041, FIS-FEDER:PI 03/1615, PI04/1509, PI04/1112, PI04/1436, PI04/1931, PI/04/2018, PI05/1079, PI05/1052, PI06/0867, PI06/1213, PI07/0314, PI/08/1151, PI09/02647, FIS-PI041436, FIS-PI081151, FISS-PI042018, FISS-PI09/02311, FISPI06/0867 FIS-PS09/00090, FIS-PI07/0252, PS09/00090, PI11/01007, PI11/02591, PI11/02038, PI13/1944, PI13/2032, PI14/00891, PI14/01687, PI16/1288, PI17/00663 and Miguel Servet-FEDER: CP11/00178, MS13/00054, and MSII16/00051), Generalitat de Catalunya-CIRIT 1999SGR 00241, La Fundació La Marató de TV3 (090430), Alicia Koplowitz Foundation 2017, Conselleria de Sanitat Generalitat Valenciana, Department of Health of the Basque Government (2005111093 and 2009111069), Provincial Government of Gipuzkoa (DFG06/004 and DFG08/001), Obra Social Cajastur, Universidad de Oviedo, Consejería de Salud de la Junta de Andalucía (grant no. 183/07), EU Commission (QLK4-1999-01422, QLK4-2002-00603, and CONTAMED FP7-ENV-212502), and Fundación Roger Torné. Global Health Institute Barcelona (ISGlobal) is a member of the CERCA Programme, Generalitat de Catalunya. A full roster of the INMA Project Investigators can be found at http://www.proyectoinma.org/presentacion-inma/listadoinvestigadores/en_listado-investigadores.html. The INUENDO study was funded by the European Commission's Seventh and Fifth Framework Programmes (FP7-ENV-2008-1-226217 and QLK4-CT-2001-00202). The polychorinated biphenyl (PCB) cohort was funded by the U.S. National Institutes of Health (grants R01 CA096525 and R03 TW007152), the EU Seventh Framework Programme FP7/2007-2023 (grant agreement OBELIX, no. 227391), Slovak Research and Development Agency (grants APVT-21-016804, APVV-0571-12, APVV-0444-11), and by the ITMS project (no. 26240120033) based on the supporting operational research and development program from the European Regional Development Fund.