Research

LINC will investigate how genes, neurodevelopmental conditions, people’s living environment, and life events influence the link between physical and mental health conditions, helping policy makers and service providers develop targeted education, health, and social care interventions.

Purpose of the study

With multiple long-term conditions becoming more common as society ages, global healthcare providers face challenges in providing the right type of care.

More than half of people over the age of 65 now live with multiple long-term physical and/or mental health conditions. As our population ages this proportion will only increase.

A number of institutions, such as the World Health Organisation and the Academy of Medical Sciences, identified multiple long-term conditions as one of the greatest challenges facing global health services both now and in the future. This has been echoed by Sir Christopher Whitty, Chief Medical Officer for England.

People with multiple health conditions often have more complex care or treatment needs as their various conditions need to be considered together, rather than individually. As a result, they often struggle to get the best care, are seen to have a worse quality of life than those with a single condition and are at risk of lower life expectancy.

While living with multiple health conditions is frequently a consequence of ageing, in some cases it can also start in childhood. For example, neurodevelopmental conditions (such as intellectual disability and autism) and children’s environmental factors (poverty, physical or sexual abuse) are known risk factors for developing multiple long-term conditions in later life.

Understanding multimorbidity

LINC will focus on a common, but serious, type of multiple long-term condition (MLTC) seen between internalising conditions (depression and anxiety)  and cardiometabolic conditions (such as heart disease and diabetes).

It has been found that approximately 80% of people with internalising conditions also develop cardiometabolic conditions. Whilst approximately 40% of people with cardiovascular disorders are seen to develop an internalising disorder. This type of multimorbidity is also more likely to be seen in people of South Asian heritage.

Both internalising and cardiometabolic disorders tend to originate in childhood. For example, certain conditions that start early in life such as neurodevelopmental conditions (such as intellectual disability or autism) are known to increase the risk of developing these conditions.

A child’s environment can also increase this risk through, for example, stressful experiences such as poverty and physical or sexual abuse. Lastly, some people are also born with a greater genetic risk of internalising, cardiometabolic and/or neurodevelopmental disorders than others.

But how exactly genes, neurodevelopmental conditions and early environmental risks influence the development of multiple long-term mental and physical health conditions is still not understood. LINC will draw on experts across the UK and Europe to explore how these factors may influence the risk of developing this type of multiple long-term conditions.

Our aims

Our study will help us understand how this type of multiple long-term condition develops and which factors make us more or less likely to develop it.

Key to LINC is that it is a collaborative, with the project benefitting from medical and research expertise at a number of research institutions. Our objectives are to better understand why the co-occurrence of internalising (e.g., depression and anxiety) and cardiometabolic conditions (e.g., cardiovascular disease, type 2 diabetes) is so common and some of the risk factors involved. Briefly, we will:

1. Investigate how it develops at different stages of life (i.e., childhood, young adulthood, later adulthood)
2. Explore the genetic, neurodevelopmental and environmental risks factors which may affect its development
3. Examine sex differences and differences between ethnic groups which may also affect the development of this type of multiple long-term condition
4. Involve a wide range of stakeholders throughout the project to help ensure our findings bring about meaningful change to policy and service delivery (e.g., health, education, social care)

What we learn will be important for the prevention of this type of multiple long-term condition in later life by identifying children who are at risk because of genetics, their sex, ethnic or economic reasons.

Exploring the risk factors

Following the health of large numbers of people over many years allows us to identify potential risks and other influencing factors.

To really explore the risk factors for this type of multiple long-term condition we need to tap into existing studies of people, of all ages, whose health has been followed over many years (known as a longitudinal study).

Large-scale studies are needed in which detailed information on health and environmental factors has been collected repeatedly, and in which genetic information has been collected from the participants.

LINC will draw on five studies which have followed the health over time of large numbers of children, adolescents and adults:

• UK Biobank
• East London Genes & Health
• Avon Longitudinal Study of Parents and Children
• Born in Bradford
• iPSYCH

By applying advanced statistical techniques to this data, we can identify which conditions occur together. This is called a disease cluster. We can then investigate whether these clusters change from childhood through to later life. Because the children and adults who took part in these studies have different ethnic and economic backgrounds, we can also look at how the disease clusters within different groups in society differ. Finally, statistical techniques also allow us to identify genetic and environmental risk factors which affect how disease clusters change over time. This knowledge can then be used to identify which people are more likely to develop this type of multiple long-term health condition.

This gives policy makers and service providers the information needed to reduce the how many people live with this type of multi long-term health condition through targeted education and health, and social care interventions.