P1230 Impact of vegan diet on the incidence of Inflammatory Bowel Diseases among Israeli young adults

Abstract Background Diet is believed to modulate intestinal inflammation through its regulatory effects on the microbiota, gut immune system, and epithelial barrier function. Previous research, mostly based on questionnaires of food consumption, showed that high dietary intake of total fats, meat and processed food is associated with an increased risk of incident IBD, while plant-based , fiber rich-diet is associated with a reduced risk of incident IBD. Between the years 1998-2017, Vegans enlisted to the Israel Defense forces (IDF) were entitled to a special allowance. Strict requirements for confirmation of vegan status were followed. We assessed whether a vegan diet protect against incident IBD in a cohort of young Israeli adults. Methods A historical prospective cohort including all Israeli adolescents enlisted between 1998-2017. The data gathered included age, sex, body mass index (BMI), country of origin, general intelligence tests (GIT), socioeconomic status (SES), and incident IBD. A multivariate logistic regression model and 1:1 propensity score-matched cohorts were utilized to calculate the OR of developing IBD in vegans compared to controls. Results The study population consisted of 1,049,005 subjects, 630,536 (60%) males, and 5941 (0.57%) vegans. The median follow-up duration was 1046 days (IQR 727-1094). Vegans came from higher SES (6.3 vs. 5.9, p<0.001), were more likely to be of European descent (47.2% vs. 25.8%, p<0.001), and had higher GIT results (63.5 vs 52.6, P<0.001). Along the study period, 2039 (0.19%) subjects developed IBD , 17 among vegans (0.29%), and 2022 among controls (0.19%) (p=0.12). In both groups, the distribution of CD and UC cases was exactly the same, with 70% of cases being CD and 30% being UC. IBD patients were more likely to be male (64.3% vs. 60.1%, p<0.001), from European origins (39% vs. 25.9%, p<0.001), and a higher SES (6.15+- 1.54 vs. 5.94+-1,64, p<0.001). Based on a multivariate logistic regression controlling for sex, country of origin, BMI, GIT and SES, a vegan diet was not associated with a reduction in IBD incidence (OR 1.14, 95% CI 0.68-1.78). Analysis of a 1:1 propensity-score-matched cohort of subjects (n=5484) demonstrated no statistically significant differences between vegans and controls regarding IBD incidence (0.29 vs. 0.32%, p=0.87). An exploratory evaluation of the impact of vegan diet on endoscopic severity was performed only in CD patients and revealed a lower incidence of large ulcers in the vegan group (57%) compared to controls (79%). Conclusion In this nationwide cohort of young Israeli adults, a vegan diet was not associated with a reduction in the incidence of IBD. Endoscoppic disease severity might be milder among vegan CD patients. References Hou JK, Abraham B, El-Serag H. Dietary intake and risk of developing inflammatory bowel disease: a systematic review of the literature. Am J Gastroenterol. 2011;106(4):563-573. doi:10.1038/ajg.2011.44 Narula N, Wong ECL, Dehghan M, et al. Association of ultra-processed food intake with risk of inflammatory bowel disease: prospective cohort study. BMJ. 2021;374:n1554. Published 2021 Jul 14. doi:10.1136/bmj.n1554 Chen J, Wellens J, Kalla R, et al. Intake of Ultra-processed Foods Is Associated with an Increased Risk of Crohn's Disease: A Cross-sectional and Prospective Analysis of 187 154 Participants in the UK Biobank. J Crohns Colitis. 2023;17(4):535-552. doi:10.1093/ecco-jcc/jjac167