Physical and Mental Health as Biopsychosocial Correlates and Pathways Associated With Symptom Severity in Irritable Bowel Syndrome: A Cross-Sectional Structural Equation Modeling Study.

INTRODUCTION

Irritable bowel syndrome (IBS) is a heterogenous disorder of gut-brain interaction, characterized by complex interaction between gastrointestinal symptoms, psychological distress and physical functioning. While physical activity is increasingly recommended as part of IBS management, the pathways through which physical and mental health relate to symptom severity remain incompletely understood.

OBJECTIVE

To explore the interrelationships between physical activity, physical health, mental health and IBS symptom severity using Structural Equation Modeling (SEM) within a biopsychosocial framework, in adults with IBS.

METHODS

In this cross-sectional exploratory study, 106 adults with a clinician-confirmed diagnosis of IBS (Rome IV criteria) completed validated questionnaires assessing IBS severity (IBS-SSS), physical activity (GPAQ), anxiety (GAD-7), depression (PHQ-8), and health-related quality of life (SF-36). Bivariate correlations were examined, followed by SEM to investigate relationships between latent constructs of physical health and mental health on IBS symptom severity.

RESULTS

Participants (mean age: 45 ± 14 years; 82% female) reported high IBS symptom severity (333 ± 89) and wide-ranging physical activity levels (mean: 3382 ± 4482 MET-min/week). Bivariate analysis showed significant correlations between IBS symptom severity and anxiety (r = 0.235, p < 0.05), depression (r = 0.240, p < 0.05) and multiple physical health domains, including pain (r = 0.454, p < 0.001). In the SEM physical health demonstrated a large but non-significant association with IBS symptom severity (β = 0.68, p = 0.065), while mental health showed no statistically significant direct path (β = 0.19, p = 0.261). Physical activity was significantly associated with physical health (β = 0.22, p < 0.001) and physical and mental health latent constructs were strongly correlated (β = 0.72).

CONCLUSION

In this exploratory SEM study physical and mental health were closely interrelated and associated with IBS symptom severity at the correlational level, although direct paths in the SEM did not reach conventional statistical significance. Physical activity was linked to physical health, suggesting a potential indirect pathway influence symptom severity. These findings support a biopsychosocial perspective and highlight the need for integrated, personalized IBS management approaches, while underscoring the important of larger, longitudinal studies to clarify causal pathways.