Stress, Diet, and Sleep Shape Irritable-Bowel-Syndrome-Specific Symptoms: The Lockdown "Cocoon Effect".

Background/Objectives: Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder affecting almost 10% of the general population, characterized by recurrent abdominal pain and altered bowel habits. Its pathophysiology is incompletely understood, but it is established that symptoms result from an interplay between several environmental- and patient-related factors. This study aimed to analyze the influence of a widespread shift in lifestyle habits and multidimensional stress on IBS manifestations. Methods: An online survey was administered during the COVID-19 lockdown in 2020 to three groups of people representative of the general population. The survey contained questions regarding socio-demographic data, dietary habits, alcohol, smoking, physical activity, sleeping, working activities, stress level, and the characteristics of gastrointestinal symptoms related to both the pre-pandemic period and the lockdown period. The definition of IBS was based on the Rome IV criteria. Multivariate analyses were used to evaluate the association between environmental variables and the occurrence/resolution of IBS. Results: A total of 2735 participants were enrolled. Among them, 122 patients (46.2%) reported symptoms' improvement during the observation period, while 118 previously healthy subjects (4.8%) developed IBS symptoms. Reduced general stress (OR = 2.2, 95%CI 1.1-4.6, p = 0.029), increased fiber intake (OR = 2.8, 95%CI 1.6-5.0, p < 0.001), and increased hours of sleep (OR = 2.0, 95%CI 1.1-3.8, p = 0.031) were associated with a high probability of IBS resolution, while increased anxiolytic pill intake (OR = 0.14, 95%CI 0.04-0.46, p = 0.001) showed a low likelihood of IBS resolution. Reduced physical activity (OR = 2.0, 95%CI 1.3-3.2, p = 0.002), increased anti-inflammatory effects (OR = 2.4, 95%CI 1.4-4.1, p = 0.002), anxiolytic pill intake (OR = 3.5, 95%CI 2.1-5.9, p < 0.001), and increased work-related stress (OR = 1.8, 95%CI 1.2-2.8, p = 0.009) were risk factors for IBS symptoms' occurrence. Reduced alcohol consumption was a protective factor (OR = 0.5, 95%CI 0.3-0.8, p = 0.006). The resolution of IBS did not affect upper gastrointestinal functional symptoms (OR = 0.2, 95%CI 0.1-0.3, p < 0.001). Conclusions: The widespread lifestyle change forced by the pandemic created a protective "Cocoon Effect", resulting in a beneficial effect in almost half of patients with IBS. Our findings provide large-scale evidence that environmental factors play a pivotal role in the pathophysiology of IBS. Specifically, stress levels, fiber intake, sleep patterns, and alcohol consumption are key modifiable drivers of symptom occurrence and resolution.