Irritable Bowel Syndrome and Non-specific Inflammatory Bowel Diseases Are Not Evolutionarily Related Diseases

Introduction

Irritable bowel syndrome (IBS) shares similar symptoms and certain pathogenetic features with inflammatory bowel disease (IBD). This raises the question of whether these factors also affect IBS. 

Analysis and Findings

Data from 4 systematic reviews were assessed, which dealt with the incidence and prevalence of IBD, the prevalence of IBS, and the distribution of lactase.

Direct comparison using Pearson's correlation coefficient showed no significant correlation between IBD and IBS (for the prevalence of Crohn's disease r = −0.14, for the prevalence of ulcerative colitis r = −0.06, for the incidence of Crohn's disease r = −0.10). Indirect comparison also revealed no relationship between the two diseases (based on lactase distribution r = −0.17, based on sunshine amount r = −0.2, based on geographic latitude r = 0.097). However, a significant correlation was found between lactase distribution and the incidence of Crohn's disease (r = −0.84), the prevalence of Crohn's disease (r = −0.55), and the prevalence of ulcerative colitis (r = −0.59). 

Conclusion

The analysis suggests that IBS and IBD do not have a similar geographical distribution. This indicates that these two diseases do not share a related evolutionary genetic background. 

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Source: Szilagyi A., Xue X. Comparison of geographic distributions of irritable bowel syndrome with inflammatory bowel disease fail to support common evolutionary roots: irritable bowel syndrome and inflammatory bowel diseases are not related by evolution. Med Hypotheses 2018 Jan; 110: 31–37, doi: 10.1016/j.mehy.2017.10.020.