Impact of socioeconomic circumstances on risks and life-course consequences of preterm birth: studies into differential exposure and susceptibility

Relevance:

Preterm birth is a significant public health problem. Affecting almost one in ten births, children born preterm are significantly more likely to face developmental problems, health and behavioural issues, and poorer educational outcomes. Preterm birth is a leading cause of mortality, morbidity and healthcare use among children globally, and to further exacerbate the issue, pregnant women who are of a lower socioeconomic status are significantly more likely to give birth preterm than more affluent women. Considering that health and educational outcomes are worse for children who grow up more disadvantaged socioeconomic conditions, and they are more likely to be born preterm, it evident that preterm birth is an important contributor to the generation of health inequalities.

Reducing health inequalities is a key area of policy interest. However, there are currently no policies or interventions to support children born preterm in the UK beyond the health services they may require. Children born preterm have worse outcomes even when they do not have an early life health problem. Thus, there is a cohort of children that needs support but do not receive it. A challenge for this situation is that we do not fully understand the complex pathways from maternal socioeconomic status to preterm birth, or the relationships between preterm birth and childhood socioeconomic conditions, and their influence on outcomes in later life. This limits the ability to intervene effectively through policy action.

Hypotheses:

This research is founded on two hypotheses. First, we can better explain inequalities in the distribution of preterm birth through understanding of how maternal risk factors, such as maternal behaviours (smoking while pregnant), or maternal health status, influence the pathway from maternal socioeconomic status to preterm birth. Second is that the impacts that preterm birth have on later life health and education outcomes is dependent on the childhood socioeconomic circumstances.

Aims:

To test my hypotheses, I have three aims for this research:
- Identify the complex pathways that lead to inequalities in the distribution of preterm birth.
- Understand how preterm birth and childhood socioeconomic conditions interact to lead to inequalities in later life.
- Evaluate the potential impact of policies and interventions at these two policy entry points on health inequalities in later life.

To do this, I will use two rich UK datasets. The UK Millennium Cohort Study is a large follow-up study of children from birth, between 2000 and 2001, through to age seventeen. The SAIL databank is a world leading data linkage capturing data on the entire population of Wales covering health, education and social circumstances. I will apply state of the art statistical techniques to these data to meet my aims.

Outcomes and Benefits:

My research will increase understanding of pathways to inequalities in preterm birth, and how preterm birth interacts with socioeconomic conditions to influence later life inequalities. It will identify children who are most at risk of negative later life outcomes related to preterm birth and socioeconomic conditions. It will also show the potential benefits of intervening at select policy points associated with preterm birth on reducing inequalities in later life. I will work with local policymakers and clinicians to ensure this research is translated into effective action to reduce the negative impacts of preterm birth. The knowledge generated by my research has the potential to reduce inequalities, improve the health of the population, and have wider social and economic benefits.

Aims
To identify the causal pathways from maternal socioeconomic status to preterm birth. To explain and quantify the interaction between preterm birth and socioeconomic conditions on later life health and educational inequalities. To evaluate the potential effectiveness of policy or intervention on reducing inequalities in preterm birth prevalence and health and educational outcomes in later life. Three research questions have been identified:
1- How do key exposures, such as maternal health and behaviours, mediate the pathway from maternal socioeconomic status to preterm birth?
2- How does preterm birth influence the relationship between maternal socioeconomic status and adolescent outcomes for health and education?
3- What is the effect of interventions to improve birth outcomes, and outcomes for children born preterm, on later life inequalities associated with socioeconomic circumstances?

Methods
Secondary analysis of data sources: Millennium Cohort Study (MCS) and the Welsh SAIL databank. The MCS is a birth cohort of almost 19,000 children born in the UK in 2000/01. The SAIL databank is a collection of anonymously linked data across Wales, including birth extracts, health data from primary and secondary care, and educational data. Analysis will be through causal mediation analysis, fourfold decomposition analysis to separate mediated and interactive effects, and simulation of intervention effects. Outcomes will be measured using mortality and morbidity measures (e.g. ICD10 diagnosis), healthcare usage and exam results at Key Stage 3, GCSE and A-Level.

Scientific and Medical Opportunities
Results will be used to inform policymakers, and Obstetric and Paediatric clinicians of potential intervention points to reduce preterm birth burden, and identify a particularly at risk cohort of children who are currently not supported by policy or intervention in the UK. The results will demonstrate the potential benefits of intervention on later life outcomes.

My proposed research will have impact on a number of groups beyond the academic beneficiaries detailed above:
- Children: Almost one in ten children are born preterm in the UK, and there is an inequalities distribution across the socioeconomic gradient; women from a more disadvantaged background are significantly more likely to give birth preterm. Children born preterm are at significantly increased risk for negative health and educational outcomes. My research will identify the interventions that are likely to prevent preterm birth amongst more disadvantaged children and support better educational and health outcomes for disadvantaged children who are born preterm. By the end of the project (three years) evidence will be produced that support effective spending on interventions for children to improve their later life outcomes. This has considerable potential to reduce the burden of preterm birth for many families.
- Health Service: Obstetricians, paediatrics, commissioners and managers all stand to benefit from my research. The research aims to identify factors which influence the prevalence of preterm birth, and the factors which influence healthcare use, health and educational outcomes for children born preterm. This evidence can be used by health service commissioning and planning to improve equity by identifying children with the most need and ensuring availability of, and access to, appropriate services. Reducing health inequalities and inequalities in access to services has been identified as a key aim for the NHS, in the Five Year Forward View, and for Public Health England.
- Policymakers at a local and national setting: By identifying the effects of preterm birth on later life outcomes in health and education, particularly for preterm births without associated health problems, my research will provide evidence for policymakers, demonstrating areas of unmet need and identifying the most effective approach for investment. Through dissemination of this evidence throughout the project, policymakers may be able to use this to lobby politically for increased children's spending in these areas. The research on intervention effects can be used by policymakers at a local level to maximise the impact from their children's spending, which will be important during times of reduced funding.
- Education and Social Care sectors: Similar to the health service, my research will support schools and social care workers in identifying children most in need, and implementing interventions which maximise benefit in a resource-scarce setting. The research will assess educational outcomes, assess the impact of institutional factors (e.g. schools) and assess the influence of social factors on causal pathways, and is therefore highly relevant to these sectors.
- Wider public: There is a potential wider impact that may be achieved through my research. First, there are future economic benefits by maximising the potential for children born preterm to thrive through increased educational attainment, increased potential for employment and reduced need for welfare support. Secondly, reducing health inequalities, and improving health, for children born preterm will lead to reduced healthcare pressures on adult health services. Finally, this research will provide evidence for the hypothesis that social conditions interact with health events to create a differential susceptibility to inequalities. This will be of significance for people with a long-term condition or disability - potentially, there is a differential susceptibility for these groups which provides opportunity for effective intervention.