General and abdominal obesity in relation to the prevalence of irritable bowel syndrome

Earlier studies on the obesity-IBS association have mostly been reported from Western nations, and limited data are available in this regard from developing countries. This study was performed to examine the association of general and abdominal obesity with Irritable bowel syndrome (IBS) in a Middle Eastern population.

In this cross-sectional study, 4763 Iranian adults participated. Data on self-reported anthropometric measurements were collected, and BMI was calculated. Overweight and obesity were defined as 25 ≤ BMI < 30 and BMI ≥ 30 kg/m² , respectively. Also, we used WC measurements to define the three categories of normal (<94 cm in men <80 cm in women), abdominal overweight (94 ≤ WC < 102 in men and 80 ≤ WC < 88 in women), and abdominal obesity (WC ≥ 102 cm in men and WC ≥ 88 cm in women). Assessment of different GI symptoms including those related to IBS was done using a validated Persian version of the Rome III questionnaire. IBS was defined as the presence of recurrent abdominal pain or discomfort at least sometimes in the last 3 months associated with 2 or more of the following features: improvement with defecation, pain onset associated with a change in frequency of stool, and pain onset associated with a change in form (appearance) of stool.

Irritable bowel syndrome was more prevalent among individuals with abdominal obesity compared with normal subjects (23.8% vs 19%). Neither in crude nor in adjusted models, we found any significant association between overweight and obesity and IBS [for overweight: OR: 0.95, 95% CI: 0.66-1.36 and for obesity: OR: 1.06, 95% CI: 0.85-1.31]. We observed a significant positive association between abdominally overweight and IBS in crude model (OR: 1.31, 95% CI: 1.09-1.60); however, this association became non-significant after adjustment for potential confounders (OR: 1.09, 95% CI: 0.82-1.44). Across BMI categories, neither in crude nor in adjusted models, we did not find any significant association between overweight (OR: 0.89, 95% CI: 0.62-1.27), obesity (OR: 1.05, 95% CI: 0.58-1.87), and abdominal pain severity. Abdominal overweight (OR: 0.96, 95% CI: 0.65-1.40) and obesity (OR: 1.61, 95% CI: 0.67-1.63) were not associated with abdominal pain severity.

It is concluded that general or abdominal obesity was not associated with odds of IBS. Future longitudinal studies are needed to clarify the association between obesity and IBS.