From exposure to embedding: how interconnected social determinants drive health inequalities-a complex adaptive system dynamics approach.

The social determinants of health (SDOH)-including socioeconomic position, education, housing, and social networks-are fundamental drivers of health inequalities worldwide. These inequalities persist because social determinants interact dynamically across time and context, with health emerging from the interplay of social, political, environmental, and biological processes in which determinants act simultaneously as causes and consequences. Early-life exposures and historical conditions produce enduring physiological vulnerability through biological embedding, encompassing stress dysregulation, inflammation, and epigenetic modifications. Feedback loops, non-linearity, and path dependence stabilise disadvantage across the life course and across generations-mechanisms that explain why interventions targeting isolated risks or single factors often yield modest or context-dependent effects. A complex adaptive systems perspective reconceptualises health inequalities as emergent outcomes of these interacting social-biological processes and identifies leverage points where systemic, multi-level interventions can shift trajectories. Promising approaches include coordinated, place-based strategies, relational continuity in primary care, and strengthened social infrastructure.