Abstract Background Early-life environmental exposures such as breastfeeding (BF) and mode of delivery shape the gut microbiome and may influence the natural history of inflammatory bowel disease (IBD)1,2. Methods This single-center retrospective study analyzed adult patients with IBD. Demographic, clinical, and environmental data were retrieved from a longitudinal hospital database. Breastfeeding was defined as exclusive breastfeeding for more than three months, and mode of delivery as vaginal or cesarean section (CS). The primary outcome was IBD-related surgery; secondary outcomes included extraintestinal manifestations (EIMs), need for biologic therapy and its intensification, and number of relapses. Results A total of 541 patients were included, comprising 301 with Crohn’s disease (CD) and 240 with ulcerative colitis (UC). The CD cohort (mean age 49.4 ± 15.2 years; mean disease duration 15.4 ± 9.2 years) included 148 women (49.2%), while the UC cohort (mean age 49.9 ± 16.8 years; mean disease duration 14.7 ± 11.7 years) included 116 women (48.3%). BF was reported in 82.1% of CD and 83.3% of UC patients, and CS in 15.6% CD and 15.8% UC patients. In UC patients, BF was independently associated with lower odds of EIMs (adjusted OR 0.23; 95% CI 0.01–0.65), but not with surgery or treatment outcomes. In CD, no significant associations were observed between early-life exposures and surgery, EIMs, or treatment parameters. Conclusion BF may confer a long-term protective effect against EIMs in UC, supporting the concept that early-life microbial and immune programming influences IBD expression. Larger, prospective, multicenter studies are warranted to confirm these findings and clarify underlying mechanisms. References: 1. Stewart CJ, Ajami NJ, O’Brien JL, et al. Temporal development of the gut microbiome in early childhood from the TEDDY study. Nature. 2018;562(7728):583-588. doi:10.1038/s41586-018-0617-x 2. Rutayisire E, Huang K, Liu Y, Tao F. The mode of delivery affects the diversity and colonization pattern of the gut microbiota during the first year of infants’ life: a systematic review. BMC Gastroenterol. 2016;16(1):86. doi:10.1186/s12876-016-0498-0 Conflict of interest: Kalakos, Nikolaos: No conflict of interest Tsitsigiannis, Konstantinos: No conflict of interest Thanos, Charalampos: No conflict of interest Georgakopoulou, Nikolia: No conflict of interest Ntailianas, Dimitrios: No conflict of interest Piskopou, Dionysia: No conflict of interest Georgiou, Evgenia: No conflict of interest Triantafyllou, Margarita: No conflict of interest Striki, Athanasia: No conflict of interest Mpraimakis, Anastasios: No conflict of interest Kotzagiannidou, Evanthia: No conflict of interest Argyropoulos, Theodoros: No conflict of interest Theodoropoulos, Loukas: No conflict of interest Michalopoulos, George: No conflict of interest Karoumpalis, Ioannis: No conflict of interest
Kalakos et al. (Thu,) studied this question.