Epidemiology as a Cornerstone of Brain Health: From Measuring Burden to Prevention, Equity and Policy

ABSTRACT Brain health has become a major public health objective across the life course. Yet brain health strategies require more than broad concepts and advocacy: they require population evidence that can measure both impairment and preserved function, follow multidimensional trajectories over time, identify determinants and inequalities, evaluate interventions and monitor policy impact. Epidemiology provides this evidence architecture. Applying it to brain health adds distinctive measurement demands, including cognitive, emotional, behavioural, social and functional outcomes; preclinical or subclinical change; the interdependence of neurological and mental health; and a life‐course perspective. We propose a six‐stage data‐to‐action framework: characterise brain‐health state and burden; map distribution, gaps and inequalities; identify determinants and estimate preventable potential; select and evaluate interventions; assess implementation, value and distributional effects; and translate, monitor and revise policy. Preserved function, life‐course trajectories, data quality, equity and stakeholder involvement are treated as cross‐cutting requirements. Global modelling initiatives and high‐quality local epidemiology are complementary evidence sources. New data sources, geospatial methods and artificial intelligence offer major opportunities, provided representativeness, validity, interoperability and equity remain explicit priorities. Brain‐health strategies should therefore be measurable by design, with epidemiology linking population evidence to effective and equitable action.