Early life adversity and life course health: an investigation of adversity clustering and associations with health

Early life adversities, such as child maltreatment, are all too common in the UK. Research to date suggests that such adversities can have long-term effects on health. For instance, adversities experienced in childhood and even during pregnancy may alter the way the body deals with stress throughout life. This can result in an increased risk of diseases such as heart disease, depression and type 2 diabetes. It is therefore important to investigate how early life adversities might be linked to poorer health to better inform the development of interventions.

Previous research into the health effects of early life adversities has been limited in a number of ways. Firstly, many studies have added up the number of adversities a child has experienced to create a score indicating 'total stress'. Unfortunately many children who experience one adversity are also more likely to experience another. The approach of tallying adversities does not help us to understand how adversities might affect health and what we can do about this. We also don't know whether experiencing adversities at certain ages (e.g. during pregnancy) has a greater effect on health than when experienced at other points in early life. There is also little evidence on whether associations between early life adversities and health are different for boys and girls. Also different types of early life adversity are likely to have different associations with health.

The aim of this project is to develop a more valid measure of early life adversity and investigate how it is related to health at different points of life. This new measure will take account of the way in which children who experience one adversity are more likely to experience another. This measure will then be applied to look at associations with health. The research will focus on mental health from childhood onwards, as well as biological markers of stress from childhood and into adulthood.

The research will use three of the UK's world-renowned longitudinal studies: the Millennium Cohort Study (MCS), Avon Longitudinal Study of Parents and Children (ALSPAC), and National Child Development Study (NCDS). These are all large studies with >15,000 participants. Each study has followed the same group of people over time. ALSPAC will be used to assess associations between early life adversities in relation to biological markers of stress from childhood into adolescence. The MCS will be used to assess whether children who experience early life adversities are more likely to have mental health problems across childhood and into adolescence. Finally, the NCDS will be used to test associations between early life adversities and both biological markers of stress in middle-age and mental health across adulthood.

The proposed project will be undertaken at the Department of Epidemiology and Public Health at UCL under the mentorship of Prof. Yvonne Kelly, with support from a network of experts in social statistics, biology and sociology in the International Centre for Life Course Studies in Society and Health. Non-academic partners will be involved from the beginning of the research process. These partners include Barnardo's, the Association of Young People's Health and the Department of Health, who will be able to feed the findings of the research into their work with vulnerable families. Outputs from the project will include at least six academic papers, presentations at six conferences, a briefing note for non-academic audiences, an end of project policy seminar for academics and non-academics, and contributions to blogs and Twitter. The project also has a strong training element to enable the principal investigator to make the transition to independent researcher.

In summary, this project has the potential to advance research in the field of early life adversities and health. It will be the first to provide evidence on how early life adversities increase the risk of poor health.

This important research project has the potential to benefit a wide range of key stakeholders, including policy makers, public organisations, the general public and the charitable sector.

1. Policymakers
The analyses on the clustering of early life adversities will represent the first step in being able to investigate life course pathways linking adversities to health. This will be done using high quality UK longitudinal data and appropriate analytical methods which have the potential to greatly advance the existing evidence base. This research will equip policymakers with good quality evidence to inform future interventions and policy development in order to prevent later health problems and subsequent costs to society, both financial and non-financial. The Department of Health will be particularly relevant to this project. Dr Ray Earwicker, Lead for Troubled Families, Homelessness and Wider Health Inequalities, will be involved as a non-academic partner from the beginning of the project. His input will be valuable to ensure the research is as policy relevant as possible and he will be able to feed the project outputs to his departmental colleagues.

2. Public organisations
It will also be important to engage with other public organisations, such as Public Health England (PHE), to further disseminate the research. PHE's remit is to reduce health inequalities and improve the nation's health and wellbeing, therefore the research is likely to be highly relevant for their work. The office of the Children's Commissioner would also be interested in this project. Their role is to promote children's rights in England, particularly those of the most vulnerable children. This research will provide further evidence for their work, particularly promoting childhood has a priority policy area.

3. General public
This research will be of significance to the general public, particularly children at risk of, or who have experienced, adversities. In particular, the research will show how early life adversity can have lifelong health impacts. The investigation of clustering of adversities will enable the basis for investigating mechanisms linking adversities to health, therefore providing information and opportunities to target interventions. This has the potential to alleviate the long-term health consequences of early life adversity at the population level.

4. Charitable sector
Charities, particularly those who work with vulnerable families, will benefit from this research. This research will provide good quality evidence to strengthen their missions to support the UK's most at risk families. To ensure that this is done successfully, two such charities (Barnardo's and the Association for Young People's Health) will be involved in this research from the outset in the form of a project advisory group. This will ensure that the research is of practical use to these organisations and they will be able to provide valuable input and feedback to this work throughout. The Association for Young People's Health champions the health and wellbeing of UK adolescents, and promotes evidence-based practice. Barnardo's offers family support and counselling services, and lobbies the government on issues affecting vulnerable families, therefore the findings of this project have the potential to feed into these activities and to the activities of similar organisations.

This exciting interdisciplinary project therefore has a wide range of beneficiaries who will be engaged with throughout the project. The ultimate impact aim of this project is to improve the health of people experiencing early life adversities. The involvement of the stakeholders above is key to ensuring the greatest possible impact of this project in attempting to reach this aim. Further information on how these stakeholders will be reached is included in the Pathways to Impact.