Mitigating the impact of childhood adversity on health outcomes across the lifecourse

Background

Childhood adversities, covering a broad range of factors, from economic hardship to an unfavourable family environment, are associated with increased risk of poor health and social outcomes over the lifecourse. Our research shows that prolonged childhood adversities lead to a 4.5 times increased risk of all-cause mortality in early adulthood. Furthermore, the experience of adversity in childhood explains around half of social inequality in mortality in early adulthood. Trajectories of poor physical and mental health stemming from childhood exposure to adversity ultimately contribute to differences in adult health and societal productivity.

While the association of childhood adversity and health outcomes are clear, there are several evidence gaps. We lack an understanding of the impact of childhood adversity on multiple clustered health and social outcomes relevant for children, for example mental health problems, obesity, educational failure and criminal justice system involvement. Understanding how childhood adversity predicts co-occurrence of these outcomes is important in the context of multi-morbidity prevention in adulthood. Furthermore, evidence on the impact of health promoting or protective factors is lacking. The extent to which interventions at different ecological levels may mitigate the impact of social adversity remains unknown. In addition, we need to better understand the pathways of macro-micro level interventions that may offer the greatest opportunity to improve health outcomes for children and young people experiencing social adversities. Interventions or protective factors that build resilience to childhood adversities may occur at different levels across the lifecourse: the macro-level (e.g., poverty reduction), community level (e.g., social cohesion and empowerment), family level (e.g., emotional and social support) and individual level (e.g., cognitive and personality development). For example, societal and family-level interventions including family emotional support that promote resilience can potentially mitigate some of these harms and adversities, but the evidence base is limited. Interventions focusing on creating a safe and supportive living environment for children may also be crucial in shaping various aspects of a child's development and overall wellbeing in later life. However, there is currently insufficient longitudinal evidence about which targets for intervention are most promising to mitigate the impact of social disadvantage and adversities on health outcomes across the lifecourse.

Aims

To assess factors that mediate or moderate the associations between clustered childhood adversities and outcomes in early adulthood. The following research questions will be addressed:

1. How do trajectories of childhood adversities impact clustered health, social and educational outcomes in adolescence, and to what extent do these effects vary by family socioeconomic status (SECs)?
2. How do factors such as increasing family income, family support and/or improving housing conditions moderate or mediate the relationship between childhood adversities and clustered outcomes in adolescence?
3. How can we work with children, young people, and relevant policy stakeholders to translate the findings from questions 1 and 2 into policy and practice?

Methods

The main focus of the project will be the quantitative analysis of longitudinal datasets. We will also involve young people (from our Liverpool Young Persons Advisory Group) and relevant stakeholders (local and national policymakers, particularly through our Child of the North APPG) throughout the project via online workshops and face-to-face engagements. Practitioners and policymakers will also be engaged in shaping the dissemination and knowledge translation aspects of the project. For the initial quantitative analysis, we will use rich longitudinal data from the UK Millennium Cohort Study on children followed to age 20 years, capturing intergenerational effects of adversity. Previous studies have shown that a small number of common childhood risk factors and adversities (i.e., poverty and parental mental health) explain a large proportion of subsequent inequalities in UK child health (mental health, obesity, cognitive disability). In this proposed project, we will employ modern causal methods, including four-way decomposition, to assess factors that mediate or moderate the associations between clustered childhood adversities and clustered outcomes in early adulthood. As an example, we will assess how outcomes in adolescence are mediated or moderated by family support, influencing the effects of adversity on later health outcomes. The four-way decomposition approach breaks down the overall effect of childhood adversities into four parts: the ‘controlled direct effect’, ‘reference interaction’, ‘mediated interaction’, and ‘pure indirect effect’. These estimates give us the tools we need to derive the ‘overall proportion eliminated’: how much of the exposure's effect can be mitigated by intervening on the mediator. To inform policy, we will further assess how differential exposure to and differential impact of the mediators contribute to inequalities in health outcomes. To address biases inherent to birth cohorts such as sample attrition, we will explore extending analyses to other data sources, including linked datasets such as SAIL, ECHILD and CIPHA, to harmonise findings in routinely collected data sources with population level coverage.