Adherence to the pro-inflammatory diet in relation to prevalence of irritable bowel syndrome

Objective There is no prior study that examined the association between nutrient-based dietary inflammatory index (DII) and odds of Irritable Bowel Syndrome (IBS). We examined the association between DII score and odds of IBS and its severity among Iranian adults. Methods In this cross-sectional study, dietary intakes of 3363 Iranian adults were examined using a validated Dish-based 106-item Semi-quantitative Food Frequency Questionnaire (DS-FFQ). DII was calculated based on dietary intakes derived from DS-FFQ. IBS was assessed using a modified Persian version of Rome III questionnaire. Results After adjustment for potential confounders, we found that participants in the highest quintile of DII score had greater chance for IBS compared with those in the lowest quintile (OR: 1.36; 95% CI: 1.03-1.80). By gender, we found a significant association between DII score and IBS among women (OR: 1.41; 95% CI: 1.00-2.00). By BMI status, overweight or obese (BMI >= 25 kg/m(2)) individuals in top quintile of DII score had greater odds for IBS than those in the bottom quintile (OR: 1.64; 95% CI: 1.07-2.53). No significant association was observed between a pro-inflammatory diet and severity of IBS symptoms. Conclusions Consumption of a pro-inflammatory diet was associated with increased odds of IBS, in particular among women and those with BMI >= 25 kg/m(2).