Impact of environmental changes forced by pandemic restrictive measures on the development and course of irritable bowel syndrome

Introduction: Irritable Bowel Syndrome (IBS) is a highly prevalent gastrointestinal disorder affecting between 5% and 10% of the general population (1). This functional disorder is characterised by recurrent abdominal pain and altered bowel habits, and greatly affects patients' quality of life, causing a significant burden to the healthcare systems worldwide (2-4). Its pathophysiology is incompletely understood, but is well established that symptoms seem to be the result of an interplay between several environmental-and patient-related factors (5, 6). Aims & Methods: This study aimed to analyse the influence of lockdownforced changes in lifestyle habits and COVID-19 pandemic stress on the development of IBS manifestations. An online survey was sent to three different groups of people representative of the Italian general population. The survey contained questions regarding socio-demographic data, dietary habits, alcohol consumption, smoking habits, physical activity, hours slept per week, working activities, stress level, presence and characteristics of gastrointestinal symptoms, related to both the pre-pandemic period and the first lockdown period. IBS definition was based on Rome IV criteria (7). Statistical analysis was carried out using the statistical software R. A P-value <0.05 was considered statistically significant. Univariate and Multivariate Cox method analysis were used to evaluate the association between exposure categorical variables and occurrence/ resolution of IBS. For the non-binary categorical variables, the Wald test was used to obtain the global value of P. Results: From April 1st to April 30th, 2020, 2,735 participants completed the survey (mean age: 39.7 ± 16.1 years, female gender: 67.6%). In the pre-pandemic era 264 patients complained symptoms consistent with Rome IV criteria for IBS, whereas 2,461 were negative. Among the former group, during lockdown 122 patients (46.2%) reported improvement of symptoms while 118 previously negative subjects (4.8%) developed IBS symptoms. Age, gender, body mass index, type of employment, teleworking and smoking during confinement were not associated with the incidence or resolution of symptoms consistent with IBS. General stress (OR = 0.86, 95%CI 0.79-0.94, P= 0.0014) and reduced fibres intake (OR = 0.33, 95%CI 0.15-0.72, P= 0.005) were associated with a low probability of resolution of IBS. Reduced physical activity (OR = 2.36, 95%CI 1.21-4.60, P= 0.009) and stress linked to COVID-19 (OR = 1.26, 95%CI 1.10-1.45, P= 0.0014) and to work activities (OR = 1.23, 95%CI 1.06-1.43, P= 0.007) were risk factors for the occurrence of IBS, whereas reduced alcohol consumption (OR =0.12, 95%CI 0.03-0.44, P= 0.001) and increased fibres intake (OR = 0.05, 95%CI 0.03-0.07, P= 0.03) showed a protective effect on the occurrence of symptoms consistent with IBS diagnosis. Conclusion: Life-style changes forced by COVID-19 lockdown resulted in a beneficial effect in almost half of patients affected by IBS, whereas they favoured the development of IBS in about 5% of healthy subjects, thus confirming that environmental factors play a pivotal role in the pathophysiology of IBS. In particular, stress, both linked and unrelated to COVID-19, fibres and alcohol intake seem to be able to influence the occurrence or resolution of IBS.