Authors: Legaz A, Moguilner S, Barttfeld P, Cuadros Castro J, Galván Rial DS, Migeot J, Farina FR, Gonzalez-Gomez R, Salazar-Londoño S, de Souza Azzi T, Alcauter S, Amoruso L, Anghinah R, Bakr M, Behrens MI, Bruno MA, Cardona JF, Chen C, Colliot O, Custodio N, d’Acremont Q, Debette S, Dzianok P, Güntekin B, Huguet J, Jarne C, Joliot M, Karageorgiou E, Khedr EM, Koopowitz SM, Kublik E, Lee J, Aksman L, Lopez S, Margaretic P, Matallana D, Matis S, Miltiadous A, Novotni G, Orio P, Parra MA, Reppermund S, de Paula França Resende E, Abrahão Salum G, Slachevsky A, Sosa Ortiz AL, Takada LT, Toh AQ, Tzallas A, Wen W, Whelan R, Yener G, Zegarra Valdivia JA, Alexoudi A, Arshad F, Atta H, Avila-Funes JA, Bonilla Santos J, Bruña R, Castelblanco-Toro SM, Chino Vilca BN, Coronel-Oliveros C, Crivello F, Cruzat J, Dellavale D, Dhooge C, DiCaterina G, Escudero J, Esquivias Farias JM, Ude Eze L, Evans TE, Farombi T, Fernández A, Fittipaldi S, Portillo F, Forno Martinic G, García AM, Garcia-Cordero I, Gaurav R, Godoy ME, Gonzalez Campo C, González Hernández A, Hanoğlu L, Hazelton JL, Herzog R, Ikiz B, Kongnyu Njamnshi A, Landin-Romero R, López ME, Maito MA, Medel V, Morales Sepúlveda JP, Ochoa Gómez JF, Ogbuagu C, Okada de Oliveira M, Ozansoy M, Palma-Espinosa J, Hilal S, Zhou JH, Piña Escudero SD, Pitman JK, Prado P, Ramírez González D, Reyes P, Santamaría García H, Schröder J, Sitt JD, Soliman RK, Soto-Añari M, Thanissery N, Ito LT, Tsuchida A, Tzourio C, Yırıkoğulları H, Yokoyama JS, Aguillon D, Miller B, Alladi S, Jiang Y, Navarro A, Babiloni C, Huepe Artigas D, Piguet O, Valdes Sosa PA, Mostert CM, Tahmasian M, Li P, Hu K, Genon S, Stein DJ, Maestú F, Pievani M, Salama M, Brodaty H, Sachdev PS, Lawlor B, Eyre HA, Miranda JJ, Baez S, Tagliazucchi E, Duran-Aniotz C, Hernandez H, Ibanez A.​

Abstract: The physical and social exposome affects human aging, and brain clocks may track its effects. However, most studies neglect multidomain exposures (physical, social and political) across diverse settings globally and their associations with brain aging. In this study, we characterized the associations between 73 country-level physical and social exposomal factors and multimodal brain age in 18,701 participants from 34 countries
(healthy individuals and those with Alzheimer’s disease, frontotemporal lobar degeneration or mild cognitive impairment). Exposome effects were assessed using generalized additive models and meta-analytic frameworks. Aggregated exposome models explained up to 15.5-fold more variance than individual exposures (delta Akaike information criterion (ΔAIC): 2,034–3,127). Physical exposome was primarily associated with accelerated structural brain aging (limbic, subcortical and cerebellar regions), whereas social exposome was more strongly associated with functional brain aging (frontotemporal and limbic networks). Exposome burden accounted for 3.3−9.1-fold higher risk of accelerated aging, exceeding effects of clinical diagnoses. Findings were out-of-sample validated in cross-sectional and longitudinal designs, remained consistent across clinical subgroups and persisted after adjustment for demographics, age correction bias, cognition, scanner type and data quality. The exposome accelerates brain aging in health and disease, underscoring the need to address physical, social and political inequities.