Background:
Diet undoubtedly plays an important role in irritable bowel syndrome (IBS). Whether regional dietary habits influence the prevalence of IBS remains unclear. Previous studies have tended to focus on individual foods. However, we hypothesized that examining food frequency patterns in relation to the worldwide prevalence of IBS may offer a more meaningful insight into this issue.

Aim:
To understand if distinct dietary clusters are associated with variation in the worldwide prevalence of IBS.

Methods:
54,127 participants from 26 countries completed online questionnaires including the Rome IV diagnostic questionnaire and the consumption frequency of 10 food groups, as part of the Rome Foundation Global Epidemiology Study (RFGES). Correspondence analysis, a data-driven clustering method based on latent class analysis (LCA) of the 10 food groups adjusted for Rome-IV IBS status and country, was employed to assess the separation of countries within these dietary clusters.

Results:
We identified four unique clusters which demonstrated marked geographical and regional differences in dietary patterns worldwide and an association with relative IBS prevalence (Figure 1). There was a significant difference in IBS prevalence between the four dietary pattern groups (P<0.001, Table 1). Cluster C had the highest IBS prevalence at 5.5% (95%CI: 5.1-5.9) with a diet rich in bread, pasta, fruit and eggs, closely followed by cluster A with a mean IBS prevalence of 5.0% (95%CI: 4.5 - 5.5) with diet including high consumption of dairy, fruits, and vegetables. Regions most represented in these two high prevalence clusters included South American, Latin American, African and Mediterranean countries (Figure 1). These were followed by cluster D predominantly represented by European and North American countries (USA and Canada), as well as Australia, with a mean IBS prevalence of 3.5% (95% CI: 3.3 - 3.7) and a diet characterized by lower consumption of tofu, rice, and eggs. Lastly, cluster B with the lowest IBS prevalence (2.6% (95%CI: 2.3 - 2.9) had a diet characterised by a high consumption of rice, eggs, fish, tofu, and vegetables, and was strongly represented by Asian countries.

Conclusion:
This study demonstrates the impact of national and regional dietary habits on the global prevalence of Rome-IV IBS. The utilization of RFGES, a robust and diverse dataset, enhances the study's findings' generalizability and validity.

Figure 1. Correspondence analysis plot illustrating the variation of dietary patterns worldwide and the association between dietary patterns and Rome IV IBS prevalence. This plot demonstrates that dietary cluster membership was very strongly influenced by country, and that dietary cluster membership is also associated with the relative prevalence of IBS.

Table 1. Summary table for the clustered 10 food types using latent class analysis adjusted for Rome IV IBS prevalence and the 26 countries.

Olafur Palsson

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