Understanding cognitive ageing: individuals, institutions, and inequalities.

Population ageing has drawn growing attention to cognitive ageing as a major public health and social policy issue. However, cognitive ageing is marked by substantial heterogeneity, reflecting not only biological and genetic processes but also the cumulative influence of social, economic, and institutional conditions across the life course. This editorial introduces a Special Issue that advances a social determinants perspective on cognitive ageing by integrating life-course, inequality, and contextual approaches across diverse geographical settings. Drawing on longitudinal surveys, administrative registers, qualitative interviews, ethnography, and mixed-method designs from Europe, North America, Latin America, and Asia, the contributions collectively conceptualize cognitive ageing as a socially structured and relational process shaped by linked lives and institutional environments. Across the collection, studies document the lasting influence of childhood conditions, education, occupational trajectories, family relations, social participation, neighbourhood contexts, and welfare regimes on later-life cognitive functioning. Several contributions highlight how inequalities by gender, race, migration background, and place shape cognitive health trajectories across the life course. Other studies demonstrate the importance of infrastructure, healthcare systems, and broader political-economic transformations for the accumulation of cognitive reserves and the distribution of cognitive risks and protections. Beyond synthesizing these substantive findings, the editorial identifies key priorities for future research, including data quality and comparability, theoretical integration, global representativeness, and the translation of findings into policy and practice. Overall, the Special Issue positions cognitive ageing as an institutionally embedded and socially patterned process unfolding across interconnected lives and broader societal contexts.