This project aims to investigate behavioural, environmental, socioeconomic and genetic determinants of irritable bowel syndrome (IBS) and its coexistence with multiple long-term conditions (multimorbidity), as well as the impact of these factors on prognosis. IBS is a common functional gastrointestinal disorder, characterised by chronic abdominal pain and altered bowel habits, and frequently co-occurs with anxiety, depression, chronic pain syndromes and cardiometabolic diseases, yet the mechanisms underlying these complex patterns remain unclear.
The research will address the following questions:
(1) How do lifestyle factors (diet, physical activity, smoking, alcohol, sleep), environmental exposures (air pollution, built environment) and socioeconomic indicators contribute to the incidence and persistence of IBS?
(2) What genetic variants and polygenic risk scores are associated with IBS onset and with specific multimorbidity patterns involving IBS?
(3) How do these behavioural, environmental, socioeconomic and genetic factors jointly influence disease course, development of additional conditions and mortality among individuals with IBS?
Objectives are:
(a) To quantify individual and combined effects of behavioural, environmental, socioeconomic and genetic determinants on IBS risk and IBS-related multimorbidity;
(b) To identify distinct multimorbidity clusters that include IBS and describe their demographic and clinical profiles;
(c) To evaluate prognostic trajectories of IBS and IBS-related multimorbidity using longitudinal follow-up data;
(d) To explore potential causal relationships using Mendelian randomisation where appropriate.
UK Biobank’s large sample size, detailed phenotyping, genomic data, longitudinal linkage to health records and environmental measures provide an excellent resource to address these questions and generate evidence to inform prevention, risk stratification and management of IBS and IBS-related multimorbidity.