Dietary quality index international and the odds of irritable bowel syndrome: a case-control study

Irritable bowel syndrome (IBS) is a common gut-brain interaction disorder. The aetiology of IBS is not entirely elucidated; however, among the risk factors, dietary factors are regarded as crucial. Previous studies have primarily investigated the association of single nutrients and food groups with the odds of IBS, rather than diet quality, which considers the interaction of food groups in the odds of disease. Thus, this study sought to investigate the association between dietary quality index international (DQI-I) and the odds of IBS in Iranian adults. In this case-control study, dietary intakes of 100 IBS cases and 310 healthy controls were examined using a validated dish-based semi-quantitative FFQ (DB-FFQ). DQI-I score was then calculated based and categorised into tertiles. The Persian version of the Rome IV questionnaire was utilised to assess IBS. Multivariable logistic regression was used to assess the association between DQI-I score and the odds of IBS. After controlling for potential confounders, no significant association was shown between DQI-I scores and IBS odds among whole and gender-stratified groups. Although DQI-I represents a healthy diet, the results of the current case-control study demonstrated that a higher DQI-I score was not associated with reduced odds of IBS in fully adjusted regression models. Considering inherent limitations as well as the scarce evidence regarding the association between DQI-I and odds of IBS, further large-scale, prospective studies are required to confirm our findings.