Air Pollution Exposure During Pregnancy and Childhood, Apoe Ε4 Status and Alzheimer Polygenic Risk Score, and Brain Structural Morphology in Preadolescents

Apolipoprotein E; Genetic modifiers; Neurodevelopment Apolipoproteïna E; Modificadors genètics; Neurodesenvolupament Apolipoproteína E; Modificadores genéticos; Neurodesarrollo Background Air pollution exposure is associated with impaired neurodevelopment, altered structural brain morphology in children, and neurodegenerative disorders. Differential susceptibility to air pollution may be influenced by genetic features. Objectives To evaluate whether the apolipoprotein E (APOE) genotype or the polygenic risk score (PRS) for Alzheimer's Disease (AD) modify the association between air pollution exposure during pregnancy and childhood and structural brain morphology in preadolescents. Methods We included 1186 children from the Generation R Study. Concentrations of fourteen air pollutants were calculated at participants’ home addresses during pregnancy and childhood using land-use-regression models. Structural brain images were collected at age 9–12 years to assess cortical and subcortical brain volumes. APOE status and PRS for AD were examined as genetic modifiers. Linear regression models were used to conduct single-pollutant and multi-pollutant (using the Deletion/Substitution/Addition algorithm) analyses with a two-way interaction between air pollution and each genetic modifier. Results Higher pregnancy coarse particulate matter (PMcoarse) and childhood polycyclic aromatic hydrocarbons exposure was differentially associated with larger cerebral white matter volume in APOE ε4 carriers compared to non-carriers (29,485 mm3 (95% CI 6,189; 52,781) and 18,663 mm3 (469; 36,856), respectively). Higher pregnancy PMcoarse exposure was differentially associated with larger cortical grey matter volume in children with higher compared to lower PRS for AD (19436 mm3 (825, 38,046)). Discussion APOE status and PRS for AD possibly modify the association between air pollution exposure and brain structural morphology in preadolescents. Higher air pollution exposure is associated with larger cortical volumes in APOE ε4 carriers and children with a high PRS for AD. This is in line with typical brain development, suggesting an antagonistic pleiotropic effect of these genetic features (i.e., protective effect in early-life, but neurodegenerative effect in adulthood). However, we cannot discard chance findings. Future studies should evaluate trajectorial brain development using a longitudinal design. The Generation R Study is conducted by the Erasmus Medical Center in close collaboration with the Faculty of Social Sciences of the Erasmus University Rotterdam, the Municipal Health Service Rotterdam area, Rotterdam, the Rotterdam Homecare Foundation, Rotterdam, and the Stichting Trombosedienst & Artsenlaboratorium Rijnmond (STAR-MDC), Rotterdam. We gratefully acknowledge the contribution of children and parents, general practitioners, hospitals, midwives, and pharmacies in Rotterdam. The general design of the Generation R Study is made possible by financial support from the Erasmus Medical Center, Rotterdam; the Erasmus University Rotterdam; the Netherlands Organization for Health Research and Development (ZonMw); the Netherlands Organization for Scientific Research (NWO); and the Ministry of Health, Welfare and Sport. A.N. was supported by a grant of the Dutch Ministry of Education, Culture, and Science and the Netherlands Organization for Scientific Research (024.001.003, Consortium on Individual Development), a grant of the Canadian Institutes of Health Research team, and by the Research Foundation Flanders (FWO). S.A. was supported by the Programa Talen_UAB-Banc de Santander. The geocodification of the addresses of the study participants and the air pollution estimations were done within the framework of a project funded by the Health Effects Institute (HEI) (Assistance Award No. R-82811201). We received funding from the Spanish Institute of Health Carlos III (CPII18/00018), the EU Commission (733,206, 824,989), and the Agence Nationale de Securite Sanitaire de l’Alimentation de l’Environnement et du Travail (EST-18 RF-25). We acknowledge support from the Spanish Ministry of Science and Innovation and State Research Agency through the “Centro de Excelencia Severo Ochoa 2019–2023” Program (CEX2018-000806-S), and support from the Generalitat de Catalunya through the CERCA Program”.