A rising tide of research and policy interest in Adverse Childhood Experiences (ACEs, e.g. child maltreatment, parental intimate partner violence or substance misuse) has led to substantial financial investment in services to prevent the health consequences of ACEs. These initiatives rest on estimates of the health burden/costs of ACEs. Yet very little research attempts to interrogate the causality of associations between ACEs and health, despite potential confounding by upstream factors such as poverty and genetics. Robust evidence that ACEs causally affect health would strengthen the rationale for investing in interventions that prevent ACEs or seek to mitigate their adverse effects. Yet if some associations are spurious or over-estimates, this risks: costs of ACEs being overstated, scarce public resources being wrongly diverted away from other upstream determinants of health such as poverty, and perpetuating a stigmatising narrative that those exposed to adversity have uniformly poor health.

In BEYOND-ACES, cutting-edge research using prospective longitudinal and genetic data from 6 international cohorts will generate a step-change in evidence about whether ACEs are causally related to health-related behaviours, physical health, and mental health. We will use robust methodologies: difference in difference (DiD) to avoid time-fixed confounding, marginal structural models (MSM) to avoid time-varying confounding, polygenic scores to evaluate gene-environment correlation, and methods to account for genetic confounding. Underpinning this is a cross-cutting programme of methodological innovation: developing DiD and MSM for use with the composite exposures necessary in ACEs research, and evaluating approaches to interrogate whether the health consequences of ACEs differ according to the timing and duration of exposure. BEYOND-ACES will move beyond the current simplistic narrative about ACEs and health, and yield a step change in the quality of research in this field.