Social determinants of health and the exposome shape aging and dementia across global populations

Social determinants of health, the conditions in which people are born, grow, live, work and age, shape brain aging and dementia. Yet evidence is dominated by Global North populations and often relies on single indicators (for example, education or income), limiting risk characterization and generalizability across settings. This Perspective provides a global, integrative overview of multidimensional, multilevel and life-course approaches to social determinants of health and exposome research in brain health. We examine composite indices and social-exposomal factors, their need for harmonization, contextual adaptation and local validation, and biological embedding through stress-related, inflammatory, metabolic, vascular and epigenetic pathways. We also discuss interactions with genetic susceptibility and the analytical challenges of modeling cumulative, time-varying and nonlinear exposures. These advances require feasible, policy-relevant implementation in resource-constrained settings. Moving beyond static, single-domain proxies towards context-sensitive measures and multilevel designs can improve risk characterization and support more equitable, globally relevant strategies for dementia prevention and precision public health.