Supplementary Material for: High ultra-processed food consumption is associated with clinical exacerbation in patients with Crohn's disease in remission - a prospective cohort study

Introduction: Diet can impact the clinical course of Crohn’s disease (CD). However, the importance of food processing level is uncertain. We aimed to evaluate whether ultra-processed foods (UPFs) are associated with an increased risk of relapse amongst patients with CD in clinical remission.
Methods: In this prospective cohort study, adult patients with CD in clinical remission, were followed for one year or until clinical relapse, as assessed by the Harvey Bradshaw index. Dietary intake was assessed using a food frequency questionnaire and a dedicated validated processed food questionnaire to evaluate UPFs consumption. Multivariable Cox proportional hazard models were used to estimate the adjusted hazard ratio of disease relapse according to high or low UPFs consumption.
Results: A total of 111 patients with CD (mean age 37.9±14.0 years) in clinical remission were followed. Over a median period of 12 months [interquartile range, 8-12], 24 patients (21.6%) experienced clinical relapse. Fecal calprotectin levels were increased at relapse visit compared to baseline (193.0 μg/g [114.0-807.0], 79.0 μg/g [17.0-274.5], respectively, P=0.002). A higher intake of UPFs was associated with an increased risk of CD relapse (HR=3.86, 95% CI 1.30-11.47). Ultra-processed breads and pastries, as well as oils and spreads, were the UPF subgroups with the strongest positive associations (HR=3.27, 95% CI 1.26-8.45; HR=2.76, 95% CI 1.02-7.45, respectively).
Conclusion: UPFs consumption is associated with an increased risk of relapse in patients with CD in remission. This study, along with future research, can contribute to establishing nutritional guidelines aimed to reduce UPFs consumption in this population.