Dimensions and Pathways

Pathways and mechanisms linking Early Life Adversities (ELAs) and adult health outcomes

This working group is focusing on one of the aims of our Network -- to establish the extent to which (a) different ELAs have similar/differing effects on adult health outcomes and (b) pathways/explanations also differ/are similar. Evidence here will help us to better understand when and where interventions to prevent and remediate adult consequences of ELAs might be effective.

Our theme involves building and interpreting evidence on the processes, pathways and mechanisms that lead to poor adult health among those exposed to adversities in early life.

The rationale for our focus is that the understanding gained will be important to guide interventions to avert or remediate long-term outcomes. Currently, we are exploring two main themes:

Theme One: Dimensions of adversity and specificity of mechanisms

A broad range of ELAs (such as neglect, threat, deprivation, macro/micronutrient deficiencies, maternal low mood) have been linked to major adult health outcomes (e.g. mental health related outcomes, non-communicable disease mortality, ischaemic heart disease). Given the range of adversities suspected to lead to unfavourable long-term outcomes a major obstacle for identifying pathways and mechanisms and their specificity concerns the inter-relatedness of ELAs. One popular response to the problem of inter-relatedness of ELAs has been to examine cumulative types of adversities, an approach that has proved effective in highlighting the increased health burden of those with multiple ELAs.

For the purpose of understanding processes, pathways and mechanisms the cumulative adversities approach has some drawbacks. Notably, we cannot assume that the same mechanisms operate across the range of ELA-adult outcome associations. To advance this field key questions include:

• can meaningful ELA dimensions be identified (and what are they) that would help take forward our efforts to understand mechanisms for ELA-adult outcome associations?
• even if conceptually distinct, are ELA dimensions researchable in general population studies with long-term follow-up?
• what other considerations (such as timing and duration of ELAs) are relevant to understanding mechanisms for later outcome(s)?

Theme Two: Pathways and mechanisms from ELAs to adult outcomes

In parallel to the dimensions of ELAs work, we are focusing on some of the primary pathways and mechanisms that potentially underlie ELA-adult outcome associations.

Given well-documented links of some ELAs with mental health and the growing literature for obesity and related outcomes we plan, initially, to consider emerging evidence relating to three putative mechanisms. These include metabolic, inflammatory and epigenetic processes.

Here, our key questions include:

• what empirical evidence exists, supportive or otherwise, for each of these potential processes acting as a mediator(s) between ELAs and adult health outcome(s)?
• does evidence vary by ELA, outcome and life-stage of outcome(s), i.e. how general or specific to ELAs or outcome(s) is the evidence to date?
• is sufficient evidence available to indicate where interventions might be directed to avert/ remediate negative health outcome(s) and what are the most important gaps for further research?
• which other processes and pathways are a high priority to consider?

Our topics and priorities will be developed following further discussions within and across the Network and its sub-themes.

Mini-project

Understanding pathways from early life adversity to inflammatory profile in mid-life: an illustrative project exploring specific early adversities and potential explanations from the life-course.