Background: Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic conditions influenced by various factors, including diet. This study examined the association between fast food consumption and IBD risk through a case-control study and a meta-analysis of epidemiological evidence.

Methods: We analyzed data from a hospital-based case-control study conducted in Riyadh. The study included 158 UC patients, 244 CD patients, and 395 controls without IBD. Fast food consumption was assessed using a self-administered questionnaire distributed before diagnoses were made. We used logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs) of UC and CD for individuals who reported daily fast food consumption. Then, we merged our results with those from other studies investigating the same association into a meta-analysis.

Results: In the case-control study, daily consumption of fast food was strongly associated with UC and CD among Saudi people: age- and sex-adjusted ORs (95% CIs) = 6.29 (3.89, 10.16) and 5.92 (3.98, 8.80), respectively. The associations remained robust after further adjustments: ORs (95% CIs) = 6.61 (3.93, 11.12) and 5.90 (3.89, 8.94), respectively. Similarly, the meta-analysis revealed higher odds of fast food intake associated with UC and CD, with pooled odds ratios (95% CIs) of 2.41 (1.07, 5.45) and 2.65 (1.23, 5.70), respectively.

Conclusions: Our findings highlight the potential role of fast food consumption in the development of IBD. From a preventive medicine perspective, fast food consumption should be discouraged to reduce the risk of IBD.