Mental health and incontinence

Context:
It is commonly believed that incontinence (involuntary loss of bladder and/or bowel control) affects only young children and the elderly, but it affects people of all ages. Incontinence can have debilitating effects on quality of life and has been described as "not life threatening, but life ruining". Despite the high prevalence and adverse effects of incontinence, research into the causes, prevention and treatment of incontinence is lacking. There is evidence that continence problems that originate in childhood can often persist into adolescence and adulthood. Our previous research was the first to find strong evidence that psychological factors in early childhood (including emotional and behaviour problems, stressful experiences, and having a mother with depression or anxiety) are associated with incontinence at primary school-age. Clinicians recognise that incontinence is strongly associated with mental health problems, but previous research has been unable to establish whether poor mental health is a cause or consequence of incontinence.

Aims and objectives:
We aim to determine the precise nature of the relationships between mental health and incontinence using existing data that has been collected from cohort studies of children, young people and adults (the Avon Longitudinal Study of Parents and Children- ALSPAC and UK Biobank). ALSPAC, also known as Children of the 90s, is an ongoing health research study that investigates biological and environmental influences on health and development across the life course. Around 14,000 pregnant women joined the study in 1991-1992 and ALSPAC children, mothers and partners have been followed up ever since. ALSPAC provides extensive data from questionnaires, research clinics, biological samples and linkage to health records.
UK Biobank has collected data from over 500,000 adults recruited in 2006-2010 and this data is being used by researchers to improve the prevention, diagnosis and treatment of a wide range of illnesses.
Using these datasets, we will apply novel and robust statistical methods to test whether (i) mental health problems (e.g. depression, anxiety) and stress (e.g. life events, childhood adversities) cause incontinence and if (ii) incontinence causes poor mental health. We will examine a range of factors that might help to explain the relationships between incontinence, mental health and stress such as parenting, toilet anxiety, peer victimisation, relationship problems, and social participation. We will also investigate whether biological factors such as inflammation (part of the body's immune response) and psychological stress reactivity (individual differences in the body's response to stress) explain the links between incontinence and mental health problems.

Potential applications and benefits:
Clinicians who treat incontinence recognise the need to prioritise research into its relationship with mental health problems and stress, because this knowledge will help them to manage their patients more effectively. People with incontinence feel strongly that there is a connection with their mental health, but mental health problems are often ignored or inadequately assessed by clinicians who treat incontinence. Our research will help clinicians to develop preventative interventions and effective therapies for incontinence. Our work will also contribute to the design of care pathways that integrate mental and physical healthcare for patients with incontinence. This could reduce the risk of patients with incontinence developing mental health problems and ensure that any existing mental health problems in these patients are assessed and treated. Understanding the origins of incontinence in childhood and the contribution of emotional/behaviour problems and stress could help to prevent it from becoming chronic. Ultimately, our research could improve the lives of people affected by incontinence and help the NHS make better use of its resources.

The proposed research will examine bi-directional relationships between mental health problems and incontinence. We will examine these associations in childhood, adolescence and adulthood using data collected from children (up to age 19 years), mothers and partners from the Avon Longitudinal Study of Parents and Children and data on incontinence from linked health records. We will conduct complementary analyses in adults using data from UK Biobank to provide us with increased statistical power and the ability to extend our analysis to older adults. The proposed project will be the first to apply novel and robust causal inference methods to examine if the relationships between mental health and incontinence are causal, and to examine the mechanisms underlying these relationships. Wherever possible, we will compare assumptions and conclusions from different methods to strengthen causal inference and to better understand the impact of various potential sources of bias on our conclusions. We will use a latent variable framework of general structural equation models (SEM) to provide maximum flexibility, allowing complex SEMs to be developed incrementally using several smaller sub-models. We will apply a range of statistical methods to examine whether relationships between mental health problems and incontinence are causal, including propensity score-based methods, marginal structural models, negative controls, and Mendelian randomisation (MR) analysis. We will examine potential mediators of the relationships between mental health problems and incontinence in ALSPAC data using a causal mediation approach based on counterfactual theory.